Objective: The aim of this study was to describe the use of the postpartum intrauterine device in the maternity ward of the Ratoma communal medical center in Conakry. Methods: This was a descriptive cross-sectional st...Objective: The aim of this study was to describe the use of the postpartum intrauterine device in the maternity ward of the Ratoma communal medical center in Conakry. Methods: This was a descriptive cross-sectional study carried out between July 1<sup>st</sup> 2015 and June 30 2016, i.e. a duration of one year. Results: A total of 551 patients received advice on various contraceptive methods. Most of this advice was given in the post-partum period (40.2%) and during antenatal care (39.1%). Of the patients advised, 87 (15.8%) used the intrauterine device. The majority of users (93%) were married and uneducated (63.2%), and 39.1% were poor. The majority (56.3%) of intra-uterine devices were inserted in the immediate post-partum period. The majority of women had no adverse events either during the first six weeks (n = 57;65.5%) or at 3<sup>rd</sup> months (n = 75;86.2%) or 6<sup>th</sup> months (n = 76;87.4%) after IUD insertion. Most users remained complication-free throughout the follow-up period (n = 76;87.4% at 6<sup>th</sup> weeks and 3<sup>rd</sup> months, and n = 77;88.5% at 6<sup>th</sup> months). The continuation rate was 89.7% at 6 weeks and 3<sup>rd</sup> months, and 87.4% at 6<sup>th</sup> months after insertion. The majority of users (87.0%) were satisfied with the care they received. Conclusion: This study showed very few complications among intrauterine device users, and high continuation and satisfaction rates. The intrauterine device is a long-acting, effective, reversible and safe contraceptive that can be used by most women for birth spacing in Guinea, where women do not regularly visit health facilities.展开更多
A cystic lesion arising from the myometrium of the uterus,termed as cystic adenomyosis,has chocolate-like,thick viscous contents and contains various amounts of endometrial stroma below the glandular epithelium.It is ...A cystic lesion arising from the myometrium of the uterus,termed as cystic adenomyosis,has chocolate-like,thick viscous contents and contains various amounts of endometrial stroma below the glandular epithelium.It is an extremely rare type of adenomyosis.CASE SUMMARY Herein,we report an unusual case of a giant cystic mass in the pelvic cavity after uterine myomectomy.The patient complained of abnormal uterine bleeding and severe dysmenorrhea.After a levonorgestrel-containing intrauterine device(LNG-IUD)was inserted,her symptoms were greatly alleviated.However,the LNG-IUD was detected in the cystic cavity during the follow-up.For fear of the intrauterine device migrating into and damaging the surrounding viscera,surgical treatment was proposed.Therefore,laparoscopic resection of the lesion and removal of the LNG-IUD were performed and cystic adenomyosis with an LNG-IUD out of the uterine cavity was diagnosed.CONCLUSION We believe that myomectomy breaking through the endometrial cavity may have been a predisposing factor for the development of cystic adenomyosis in this case.展开更多
BACKGROUND An intrauterine device(IUD)is a commonly used contraceptive among women in China.It is widely used because it is safe,effective,simple,economic,and reversible.Among the possible complications,an ectopic IUD...BACKGROUND An intrauterine device(IUD)is a commonly used contraceptive among women in China.It is widely used because it is safe,effective,simple,economic,and reversible.Among the possible complications,an ectopic IUD in the bladder is rare.It occurs insidiously,has a long course,is associated with a high risk for injury,and is difficult to treat.CASE SUMMARY A 44-year-old woman was admitted for repeated episodes of urinary frequency,urgency,and dysuria over three months.Laboratory tests revealed significantly elevated urine leukocytes and bacteria.Urine culture suggested colonization with Enterococcus faecalis.Abdominal computed tomography images suggested an abnormally positioned IUD that was protruding into the bladder.Cystoscopy revealed a metallic foreign body with multiple stones on its surface in the left posterior bladder wall.The foreign body measured approximately 1 cm.Hysteroscopy revealed the arm of a V-type metal IUD embedded in the middle and upper sections of the anterior wall of the cervical canal.The majority of the IUD was located in the uterine cavity.Cystoscopy was performed,and a holmium laser was utilized to break the stones attached to the portion of the IUD in the bladder.The IUD was then removed through hysteroscopy.CONCLUSION Ectopic IUDs in the bladder can be diagnosed with thorough imaging and safely removed through cystoscopy or hysteroscopy.展开更多
<strong>Objective: </strong><span><span><span style="font-family:""><span style="font-family:Verdana;">The purpose of this study was to analyze the opinions...<strong>Objective: </strong><span><span><span style="font-family:""><span style="font-family:Verdana;">The purpose of this study was to analyze the opinions of gynecologists, midwives, and interns/Specialist students practicing in Senegal about the use of IUD, and to assess factors that stand as obstacles to IUD prescribing. </span><b><span style="font-family:Verdana;">Patients and methods: </span></b><span style="font-family:Verdana;">An online questionnaire was developed to assess providers’ IUD practices and attitudes. The questionnaire was based on the one used in a Swiss study on the same topic. The platform used was Google forms. The questionnaire was shared in associative platforms involving gynecologists, midwives and interns/Specialist students. </span><b><span style="font-family:Verdana;">Results and comments: </span></b><span style="font-family:Verdana;">We received 292 feedbacks. Gynecologists represented 13.7% of the sample, interns and specialist students 11.3% and midwives 76%. Parity is a determining factor in IUD selection. The care-providers were concerned about the followings, which might have prevented the use of IUD, even </span><span style="font-family:Verdana;">though it </span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">was</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> indicated: infections (75.7%), pelvic pain (61.3%), expulsion (48.3%), increased risk of perforation (46.9%), women’s appreciation </span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">(45.2%), ectopic pregnancy (33.9%) and sexual behavior (28.4%). </span><b><span style="font-family:Verdana;">Conclusion: </span></b><span style="font-family:Verdana;">Our study reveals that providers’ apprehensions and concerns severely limit the availability of IUDs. These concerns are often unfounded, based on personal experiences and not on official recommendations. Parity is a major obstacle.</span></span></span></span>展开更多
Effects of two types of intrauterine device (IUD) on the prostaglandins and endothelin (ET) in uterus and on the endometrial morphology in rats and rabbits, and Cu 2+ releasing amounts of both IUDs in vitro were obser...Effects of two types of intrauterine device (IUD) on the prostaglandins and endothelin (ET) in uterus and on the endometrial morphology in rats and rabbits, and Cu 2+ releasing amounts of both IUDs in vitro were observed. The results showed that the inhibiting action of the indomethacin releasing copper IUD (FICu IUD) on the PGI 2 was stronger than that on the TXA 2, the ratio of 6 keto PGF 1α /TXB 2 was reduced with the increase of the doses. There were significant differences between the groups. The FICu IUD could inhibit the rising of the ET level and lighten the endometrial impairment caused by the FCu IUD, and promote copper ion release. It was suggested that indomethacin released by FICu IUD could effectively reduce abnormal uterine bleeding.展开更多
Objective: The purpose of this study was to determine the barriers to intrauterine device (IUD) use at a University-Based Women’s Clinic. Methods: This study is a cross-sectional survey of a convenience sample of sub...Objective: The purpose of this study was to determine the barriers to intrauterine device (IUD) use at a University-Based Women’s Clinic. Methods: This study is a cross-sectional survey of a convenience sample of subjects receiving obstetrical care at a University-Based Women’s Clinic. Eligible women who consented to participate self-administered a 16-question survey during a routine prenatal visit. Descriptive statistics were used to report participants’ demographics and history of contraception use. Additionally, subjects were asked if they would consider IUD use in the future. Results: A total of 160 women participated in this study. The average age of this sample was 24.9 (SD = 6.3). The majority were in low income and low education categories. Only 5% of women reported previous IUD use. 27% of women surveyed desired more information regarding IUD contraception. 19% of participants would consider using an IUD in the future and 25% would consider?IUD in the future if they knew more about them. Insurance and financial constraints were cited as barriers to IUD use. 4% of the sample reported that they had used an IUD previously and were unhappy with it due to pain and discomfort. 18% would not consider an IUD because they had heard about side effects. 68%?of the surveyed sample reported unintended pregnancies. Conclusion: The two most common barriers to IUD use in this patient population was lack of knowledge?and concern about side effects. Increasing patients’ knowledge of IUDs has the potential to increase IUD utilization in this clinic population which reported a 68% rate of unintended pregnancy.展开更多
Intraunterine device (IUD) is a safe, effective and feasible method used for reversible contraception worldwide. Transvesical migration of an Intrauterine device (IUD) is a rare complication. We describe a case in who...Intraunterine device (IUD) is a safe, effective and feasible method used for reversible contraception worldwide. Transvesical migration of an Intrauterine device (IUD) is a rare complication. We describe a case in whom initially a plain abdominopelvic radiography demonstrated calcified string of an IUD in a 42-year-old woman with recurrent lower urinary symptoms (LUTS) and urinary tract infection since 2 years earlier. The IUD had been inserted 12 years earlier and 3 years after placement of the IUD, the patient experienced an uneventful pregnancy and a successful delivery. Sonographic images and later on the cystoscopic procedure confirmed the diagnosis of transvesical migration of the IUD. The IUD was removed using cystoscopic procedure, leaving no complication.展开更多
Objective: To assess levonorgestrel-releasing intrauterine system LNG-IUS (Mirena?) application at caesarean section (CS). Design: Randomized, comparative study. Setting: Department of obstetrics and gynecology in a p...Objective: To assess levonorgestrel-releasing intrauterine system LNG-IUS (Mirena?) application at caesarean section (CS). Design: Randomized, comparative study. Setting: Department of obstetrics and gynecology in a primary reference hospital at Puebla City, Mexico. Sample: 396 women requiring CS signed informed consent and were randomly allocated to the post-placental application of LNG-IUS (198) or Copper T 380 A (198). Methods: Follow up visits at 6 weeks, and 6 and 12 months were performed. Main Outcomes Measures: IUDs expulsion, maternal and babies’ health conditions, breastfeeding and menstrual patterns, adverse effects and pregnancies. Differences between groups were analyzed by Fisher and X2 tests, Odds ratios, relative risk and 95% confidence limits, as appropriate. Results: After one year of follow up, no pregnancies were reported. The IUD expulsion rate was 4.5% in each group. LNG-IUS users had a higher incidence of amenorrhea (OR 2.5 95% CI 2.2 - 3) and menstrual patterns significantly brief and lighter than Copper T 380 A (p < 0.001) with lower incidence of dysmenorrhea (OR 0.1 95% CI 0.04 - 0.2). No detrimental effects of LNG-IUS on breastfeeding was observed and interestingly babies weights of LNG-IUS users was slightly above the average for age compared with Copper T 380 A users. This was probably related with a major proportion of women with normal ferritin serum levels (94% vs 68%) leading to better mother’s general condition. Conclusions: LNG-IUS inserted during CS provides high efficacy contraception with additional benefits, mainly reducing menstrual bleeding and doing so, faster recovery of ferrous homeostasis after CS.展开更多
AIM: To review the safety(infection, perforation) andefficacy(expulsion, continuation rates, pregnancy) of intrauterine device(IUD) insertion in the postpartum period. METHODS: MEDLINE, Pub Med and Google Scholar were...AIM: To review the safety(infection, perforation) andefficacy(expulsion, continuation rates, pregnancy) of intrauterine device(IUD) insertion in the postpartum period. METHODS: MEDLINE, Pub Med and Google Scholar were searched for randomized controlled trials and prospective cohort studies of IUD insertions at different times during the postpartum period. Time of insertion during the postpartum period was documented specifically, immediate post placenta period(within 10 min), early post placenta period(10 min to 72 h), and delayed/interval period(greater than 6 wk). Other study variables included mode of delivery, vaginal vs cesarean, manual vs use of ring forceps to insert the IUD. RESULTS: IUD insertion in the immediate postpartum(within 10 min of placental delivery), early postpartum(10 min up to 72 h) and Interval/Delayed(6 wk onward) were found to be safe and efficacious. Expulsion rates were found to be highest in the immediate postpartum groups ranging from 14% to 27%. Immediate post placental insertion found to have expulsion rates that ranged from 3.6% to 16.2%. Expulsion rate was significantly higher after insertion following vaginal vs cesarean delivery. The rates of infection, perforation and unplanned pregnancy following postpartum IUD insertion are low. Method of insertion such as with ring forceps, by hand, or another placement method unique to the type of IUD did not show any significant difference in expulsion rates. Uterine perforations are highest in the delayed/interval IUD insertion groups.Breastfeeding duration and infant development are not affected by delayed/interval insertion of the nonhormonal(copper) IUD or the Levonorgestrel IUD. Timing of the Levonorgestrel IUD insertion may affect breastfeeding. CONCLUSION: IUD insertion is safe and efficacious during the immediate postpartum, early postpartum and delayed postpartum periods. Expulsion rates are highest after vaginal delivery and when inserted during the immediate postpartum period. IUD associated infection rates were not increased by insertion during the postpartum period over interval insertion rates.There is no evidence that breastfeeding is negatively affected by postpartum insertion of copper or hormonesecreting IUD. Although perforation rates were higher when inserted after lactation was initiated. Randomized controlled trials are needed to further elucidate the consequence of lactation on postpartum insertion. Despite the concerns regarding expulsion, perforation and breastfeeding, current evidence indicates that a favorable risk benefit ratio in support of postpartum IUD insertion. This may be particularly relevant for women for whom barriers exist in achieving desired pregnancy spacing.展开更多
Three hundred and eighty four women in Shanghai who delivered vaginally and chose IUD for contraception received the copper T 380A IUD inserted vaginally within 10 min after delivery of the placenta(i.e.,immediate pos...Three hundred and eighty four women in Shanghai who delivered vaginally and chose IUD for contraception received the copper T 380A IUD inserted vaginally within 10 min after delivery of the placenta(i.e.,immediate postplacental insertion, IPPI). Among them, 98.70% were primipara. The women were randomly divided into two groups: IUD inserted by hand and IUD insreted by ring forceps. Using Life Table Method and χ 2 test, expulsion and other discontinuation rates were compared at 6, 12, 24, and 36 months post insertion between these two different groups. No uterine perforation, infection or prolonged period of lochia occurred in the 384 cases. Expulsions were the main reason for discontinuation. From 6 months to 36 months, the gross cumulative rates of all discontinuation events (expulsion, pregnancy, removal for bleeding/pain, etc.) were not statistically significantly different (P>0.05). The results suggest that these two different insertion techniques do not significantly affect discontinuation rate in vaginal IPPI using the TCu 380 A, which appears to be suitable for postpartum insertion in Chinese women. Other relevant issues, such as breast feeding and IUD position in uterine cavity, are also analyzed and discussed in this paper.展开更多
Setting: Provincial General Reference Hospital of Bukavu, General Reference Hospital of Panzi, General Reference Hospital of Ciriri, General Reference Hospital of Nyatende and Biopharm Hospital Center. Objective: Cont...Setting: Provincial General Reference Hospital of Bukavu, General Reference Hospital of Panzi, General Reference Hospital of Ciriri, General Reference Hospital of Nyatende and Biopharm Hospital Center. Objective: Contribute to the improvement of the anesthetic ECP of patients benefiting from MVA for incomplete abortion, Describe the methodology used for adoption of the dosage formula in Anesthesia for MVA, present the mathematical demonstration leading to the dosage formula in anesthesia for MVA. Materials and Methods: Our study was descriptive by mathematical demonstration of obtaining the equilibrium constant of the dosage formula of bipuvacaine 0.1% and Fentanyl 50 µg% adapted to the weight and specific size of patients treated anesthetically in MVA cases for incomplete abortion. We also carried out an operational research by first determining the interval where our equilibrium constant is included and secondly by means of the ends of the intervals found correlated to the ends of intervals of possible weights and sizes in the being normal human female of childbearing age to arrive at the real numerical value of the equilibrium constant of the BUKAVU Dosage Formula in the case of anesthesia for MVA during the management of incomplete abortions. Results: TWO-STAGE OPERATIONAL RESEARCH: • Determination of the interval where the equilibrium constant x = −0.95 x x by crossing the means between the extremes of volumes of anesthetic drugs giving a satisfactory sensory block without hemodynamic disturbance and the extremes of normal weight and height for women of childbearing age. We ended up with X = 0.37. Conclusion: At the end of our study which had the general objectives of contributing to the improvement of the anesthetic PEC of patients receiving MVA for incomplete abortion and specific objectives of describing the methodology used for adoption of the dosage formula in Anesthesia for MVA and present the mathematical demonstration which resulted in the dosage formula in nesthesia for MVA, it appears that the dosage formula of Bukavu, in case of intrathecal spinal analgesia of MVA for incomplete abortion provides precision on the specificity of the doses of bipuvacaine hypobarre 0.1% and Fentanyl 50 µg% reported to each patient according to her weight and height. Its application could therefore reduce morbidity and mortality and improve patient-practitioner comfort in the event of MVA for incomplete abortion following the dosage precision it provides.展开更多
The HIT-PSI is a linear plasma device built for physically simulating the high heat flux environment of future reactor divertors to test/develop advanced target plate materials.In this study,the geometry-modified SOLP...The HIT-PSI is a linear plasma device built for physically simulating the high heat flux environment of future reactor divertors to test/develop advanced target plate materials.In this study,the geometry-modified SOLPS-ITER program is employed to examine the effects of the magnetic field strength and neutral pressure in the device on the heat flux experienced by the target plate of the HIT-PSI device.The findings of the numerical simulation indicate a positive correlation between the magnetic field strength and the heat flux density.Conversely,there is a negative correlation observed between the heat flux density and the neutral pressure.When the magnetic field strength at the axis exceeds 1 tesla and the neutral pressure falls below 10 Pa,the HIT-PSI has the capability to attain a heat flux of 10 MW·m-2 at the target plate.The simulation results offer a valuable point of reference for subsequent experiments at HIT-PSI.展开更多
Two-dimensional(2D)materials have attracted tremendous interest in view of the outstanding optoelectronic properties,showing new possibilities for future photovoltaic devices toward high performance,high specific powe...Two-dimensional(2D)materials have attracted tremendous interest in view of the outstanding optoelectronic properties,showing new possibilities for future photovoltaic devices toward high performance,high specific power and flexibility.In recent years,substantial works have focused on 2D photovoltaic devices,and great progress has been achieved.Here,we present the review of recent advances in 2D photovoltaic devices,focusing on 2D-material-based Schottky junctions,homojunctions,2D−2D heterojunctions,2D−3D heterojunctions,and bulk photovoltaic effect devices.Furthermore,advanced strategies for improving the photovoltaic performances are demonstrated in detail.Finally,conclusions and outlooks are delivered,providing a guideline for the further development of 2D photovoltaic devices.展开更多
The current investigation offers an innovative synthetic solution regarding electrochromic(EC)and energy storage applications by exploring phenoxazine(POZ)moiety.Subsequently,three POZ-based polymers(polyimide,polyazo...The current investigation offers an innovative synthetic solution regarding electrochromic(EC)and energy storage applications by exploring phenoxazine(POZ)moiety.Subsequently,three POZ-based polymers(polyimide,polyazomethine,and polyamide)were synthesized to ascertain the superior performer.The polyamide exhibited remarkable attributes,including high redox stability during 500 repetitive CVs,optical contrast of 61.98%,rapid response times of 1.02 and 1.38 s for coloring and bleaching,EC efficiency of 280 cm^(2)C^(-1).and decays of the optical density and EC efficiency of only 12.18%and 6.23%after 1000 cycles.Then,the energy storage performance of polyamide PA was tested,for which the following parameters were obtained:74.7 F g^(-1)(CV,scan rate of 10 mV s^(-1))and 118 F g^(-1)(GCD,charging current of 0.1 A g^(-1)).Then,the polyamide was tested in EES devices,which yielded the following EC parameters:an optical contrast of 62.15%,response times of 9.24 and 5.01 s for coloring and bleaching,EC efficiency of 178 cm^(2)C^(-1),and moderate decays of 20.25%and 23.24%for the optical density and EC efficiency after 500 cycles.The energy storage performance included a capacitance of 106 F g^(-1)(CV,scan rate of 0.1 mV s^(-1))and 9.23 F g^(-1)(GCD,charging current of 0.1 A g^(-1)),capacitance decay of 11.9%after500 cycles,and 1.7 V retention after 2 h.Also,two EES devices connected in series powered a 3 V LED for almost 30 s.展开更多
Non-magnetic semiconductor materials and their devices have attracted wide attention since they are usually prone to exhibit large positive magnetoresistance(MR)effect in a low static magnetic field environment at roo...Non-magnetic semiconductor materials and their devices have attracted wide attention since they are usually prone to exhibit large positive magnetoresistance(MR)effect in a low static magnetic field environment at room temperature.However,how to obtain a large room-temperature negative MR effect in them remains to be studied.In this paper,by designing an Au/n-Ge:Sb/Au device with metal electrodes located on identical side,we observe an obvious room-temperature negative MR effect in a specific 50 T pulsed high magnetic field direction environment,but not in a static low magnetic field environment.Through the analysis of the experimental measurement of the Hall effect results and bipolar transport theory,we propose that this unconventional negative MR effect is mainly related to the charge accumulation on the surface of the device under the modulation of the stronger Lorentz force provided by the pulsed high magnetic field.This theoretical analytical model is further confirmed by regulating the geometry size of the device.Our work sheds light on the development of novel magnetic sensing,magnetic logic and other devices based on non-magnetic semiconductors operating in pulsed high magnetic field environment.展开更多
Atomically thin MoSe_(2) layers,as a core member of the transition metal dichalcogenides(TMDs)family,benefit from their appealing properties,including tunable band gaps,high exciton binding energies,and giant oscillat...Atomically thin MoSe_(2) layers,as a core member of the transition metal dichalcogenides(TMDs)family,benefit from their appealing properties,including tunable band gaps,high exciton binding energies,and giant oscillator strengths,thus pro-viding an intriguing platform for optoelectronic applications of light-emitting diodes(LEDs),field-effect transistors(FETs),sin-gle-photon emitters(SPEs),and coherent light sources(CLSs).Moreover,these MoSe_(2) layers can realize strong excitonic emis-sion in the near-infrared wavelengths,which can be combined with the silicon-based integration technologies and further encourage the development of the new generation technologies of on-chip optical interconnection,quantum computing,and quantum information processing.Herein,we overview the state-of-the-art applications of light-emitting devices based on two-dimensional MoSe_(2) layers.Firstly,we introduce recent developments in excitonic emission features from atomically thin MoSe_(2) and their dependences on typical physical fields.Next,we focus on the exciton-polaritons and plasmon-exciton polaritons in MoSe_(2) coupled to the diverse forms of optical microcavities.Then,we highlight the promising applications of LEDs,SPEs,and CLSs based on MoSe_(2) and their heterostructures.Finally,we summarize the challenges and opportunities for high-quality emis-sion of MoSe_(2) and high-performance light-emitting devices.展开更多
High-performance ion-conducting hydrogels(ICHs)are vital for developing flexible electronic devices.However,the robustness and ion-conducting behavior of ICHs deteriorate at extreme tempera-tures,hampering their use i...High-performance ion-conducting hydrogels(ICHs)are vital for developing flexible electronic devices.However,the robustness and ion-conducting behavior of ICHs deteriorate at extreme tempera-tures,hampering their use in soft electronics.To resolve these issues,a method involving freeze–thawing and ionizing radiation technology is reported herein for synthesizing a novel double-network(DN)ICH based on a poly(ionic liquid)/MXene/poly(vinyl alcohol)(PMP DN ICH)system.The well-designed ICH exhibits outstanding ionic conductivity(63.89 mS cm^(-1) at 25℃),excellent temperature resistance(-60–80℃),prolonged stability(30 d at ambient temperature),high oxidation resist-ance,remarkable antibacterial activity,decent mechanical performance,and adhesion.Additionally,the ICH performs effectively in a flexible wireless strain sensor,thermal sensor,all-solid-state supercapacitor,and single-electrode triboelectric nanogenerator,thereby highlighting its viability in constructing soft electronic devices.The highly integrated gel structure endows these flexible electronic devices with stable,reliable signal output performance.In particular,the all-solid-state supercapacitor containing the PMP DN ICH electrolyte exhibits a high areal specific capacitance of 253.38 mF cm^(-2)(current density,1 mA cm^(-2))and excellent environmental adaptability.This study paves the way for the design and fabrication of high-performance mul-tifunctional/flexible ICHs for wearable sensing,energy-storage,and energy-harvesting applications.展开更多
Tunable Airy beams with controllable propagation trajectories have sparked interest in various fields,such as optical manipulation and laser fabrication.Existing research approaches encounter challenges related to ins...Tunable Airy beams with controllable propagation trajectories have sparked interest in various fields,such as optical manipulation and laser fabrication.Existing research approaches encounter challenges related to insufficient compactness and integration feasibility,or they require enhanced tunability to enable real-time dynamic manipulation of the propagation trajectory.In this work,we present a novel method that utilizes a dual metasurface system to surpass these limitations,significantly enhancing the practical potential of the Airy beam.Our approach involves encoding a cubic phase profile and two off-axis Fresnel lens phase profiles across the two metasurfaces.The validity of the proposed strategy has been confirmed through simulation and experimental results.The proposed meta-device addresses the existing limitations and lays the foundation for broadening the applicability of Airy beams across diverse domains,encompassing light-sheet microscopy,laser fabrication,optical tweezers,etc.展开更多
Identifying a device and detecting a change in its position is critical for secure devices management in the Internet of Things(IoT).In this paper,a device management system is proposed to track the devices by using a...Identifying a device and detecting a change in its position is critical for secure devices management in the Internet of Things(IoT).In this paper,a device management system is proposed to track the devices by using audio-based location distinction techniques.In the proposed scheme,traditional cryptographic techniques,such as symmetric encryption algorithm,RSA-based signcryption scheme,and audio-based secure transmission,are utilized to provide authentication,non-repudiation,and confidentiality in the information interaction of the management system.Moreover,an audio-based location distinction method is designed to detect the position change of the devices.Specifically,the audio frequency response(AFR)of several frequency points is utilized as a device signature.The device signature has the features as follows.(1)Hardware Signature:different pairs of speaker and microphone have different signatures;(2)Distance Signature:in the same direction,the signatures are different at different distances;and(3)Direction Signature:at the same distance,the signatures are different in different directions.Based on the features above,amovement detection algorithmfor device identification and location distinction is designed.Moreover,a secure communication protocol is also proposed by using traditional cryptographic techniques to provide integrity,authentication,and non-repudiation in the process of information interaction between devices,Access Points(APs),and Severs.Extensive experiments are conducted to evaluate the performance of the proposed method.The experimental results show that the proposedmethod has a good performance in accuracy and energy consumption.展开更多
文摘Objective: The aim of this study was to describe the use of the postpartum intrauterine device in the maternity ward of the Ratoma communal medical center in Conakry. Methods: This was a descriptive cross-sectional study carried out between July 1<sup>st</sup> 2015 and June 30 2016, i.e. a duration of one year. Results: A total of 551 patients received advice on various contraceptive methods. Most of this advice was given in the post-partum period (40.2%) and during antenatal care (39.1%). Of the patients advised, 87 (15.8%) used the intrauterine device. The majority of users (93%) were married and uneducated (63.2%), and 39.1% were poor. The majority (56.3%) of intra-uterine devices were inserted in the immediate post-partum period. The majority of women had no adverse events either during the first six weeks (n = 57;65.5%) or at 3<sup>rd</sup> months (n = 75;86.2%) or 6<sup>th</sup> months (n = 76;87.4%) after IUD insertion. Most users remained complication-free throughout the follow-up period (n = 76;87.4% at 6<sup>th</sup> weeks and 3<sup>rd</sup> months, and n = 77;88.5% at 6<sup>th</sup> months). The continuation rate was 89.7% at 6 weeks and 3<sup>rd</sup> months, and 87.4% at 6<sup>th</sup> months after insertion. The majority of users (87.0%) were satisfied with the care they received. Conclusion: This study showed very few complications among intrauterine device users, and high continuation and satisfaction rates. The intrauterine device is a long-acting, effective, reversible and safe contraceptive that can be used by most women for birth spacing in Guinea, where women do not regularly visit health facilities.
文摘A cystic lesion arising from the myometrium of the uterus,termed as cystic adenomyosis,has chocolate-like,thick viscous contents and contains various amounts of endometrial stroma below the glandular epithelium.It is an extremely rare type of adenomyosis.CASE SUMMARY Herein,we report an unusual case of a giant cystic mass in the pelvic cavity after uterine myomectomy.The patient complained of abnormal uterine bleeding and severe dysmenorrhea.After a levonorgestrel-containing intrauterine device(LNG-IUD)was inserted,her symptoms were greatly alleviated.However,the LNG-IUD was detected in the cystic cavity during the follow-up.For fear of the intrauterine device migrating into and damaging the surrounding viscera,surgical treatment was proposed.Therefore,laparoscopic resection of the lesion and removal of the LNG-IUD were performed and cystic adenomyosis with an LNG-IUD out of the uterine cavity was diagnosed.CONCLUSION We believe that myomectomy breaking through the endometrial cavity may have been a predisposing factor for the development of cystic adenomyosis in this case.
文摘BACKGROUND An intrauterine device(IUD)is a commonly used contraceptive among women in China.It is widely used because it is safe,effective,simple,economic,and reversible.Among the possible complications,an ectopic IUD in the bladder is rare.It occurs insidiously,has a long course,is associated with a high risk for injury,and is difficult to treat.CASE SUMMARY A 44-year-old woman was admitted for repeated episodes of urinary frequency,urgency,and dysuria over three months.Laboratory tests revealed significantly elevated urine leukocytes and bacteria.Urine culture suggested colonization with Enterococcus faecalis.Abdominal computed tomography images suggested an abnormally positioned IUD that was protruding into the bladder.Cystoscopy revealed a metallic foreign body with multiple stones on its surface in the left posterior bladder wall.The foreign body measured approximately 1 cm.Hysteroscopy revealed the arm of a V-type metal IUD embedded in the middle and upper sections of the anterior wall of the cervical canal.The majority of the IUD was located in the uterine cavity.Cystoscopy was performed,and a holmium laser was utilized to break the stones attached to the portion of the IUD in the bladder.The IUD was then removed through hysteroscopy.CONCLUSION Ectopic IUDs in the bladder can be diagnosed with thorough imaging and safely removed through cystoscopy or hysteroscopy.
文摘<strong>Objective: </strong><span><span><span style="font-family:""><span style="font-family:Verdana;">The purpose of this study was to analyze the opinions of gynecologists, midwives, and interns/Specialist students practicing in Senegal about the use of IUD, and to assess factors that stand as obstacles to IUD prescribing. </span><b><span style="font-family:Verdana;">Patients and methods: </span></b><span style="font-family:Verdana;">An online questionnaire was developed to assess providers’ IUD practices and attitudes. The questionnaire was based on the one used in a Swiss study on the same topic. The platform used was Google forms. The questionnaire was shared in associative platforms involving gynecologists, midwives and interns/Specialist students. </span><b><span style="font-family:Verdana;">Results and comments: </span></b><span style="font-family:Verdana;">We received 292 feedbacks. Gynecologists represented 13.7% of the sample, interns and specialist students 11.3% and midwives 76%. Parity is a determining factor in IUD selection. The care-providers were concerned about the followings, which might have prevented the use of IUD, even </span><span style="font-family:Verdana;">though it </span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">was</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> indicated: infections (75.7%), pelvic pain (61.3%), expulsion (48.3%), increased risk of perforation (46.9%), women’s appreciation </span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">(45.2%), ectopic pregnancy (33.9%) and sexual behavior (28.4%). </span><b><span style="font-family:Verdana;">Conclusion: </span></b><span style="font-family:Verdana;">Our study reveals that providers’ apprehensions and concerns severely limit the availability of IUDs. These concerns are often unfounded, based on personal experiences and not on official recommendations. Parity is a major obstacle.</span></span></span></span>
基金This project was supported by a grant from Hubei Science and Technology Com mittee(No.96 1P190 1)
文摘Effects of two types of intrauterine device (IUD) on the prostaglandins and endothelin (ET) in uterus and on the endometrial morphology in rats and rabbits, and Cu 2+ releasing amounts of both IUDs in vitro were observed. The results showed that the inhibiting action of the indomethacin releasing copper IUD (FICu IUD) on the PGI 2 was stronger than that on the TXA 2, the ratio of 6 keto PGF 1α /TXB 2 was reduced with the increase of the doses. There were significant differences between the groups. The FICu IUD could inhibit the rising of the ET level and lighten the endometrial impairment caused by the FCu IUD, and promote copper ion release. It was suggested that indomethacin released by FICu IUD could effectively reduce abnormal uterine bleeding.
文摘Objective: The purpose of this study was to determine the barriers to intrauterine device (IUD) use at a University-Based Women’s Clinic. Methods: This study is a cross-sectional survey of a convenience sample of subjects receiving obstetrical care at a University-Based Women’s Clinic. Eligible women who consented to participate self-administered a 16-question survey during a routine prenatal visit. Descriptive statistics were used to report participants’ demographics and history of contraception use. Additionally, subjects were asked if they would consider IUD use in the future. Results: A total of 160 women participated in this study. The average age of this sample was 24.9 (SD = 6.3). The majority were in low income and low education categories. Only 5% of women reported previous IUD use. 27% of women surveyed desired more information regarding IUD contraception. 19% of participants would consider using an IUD in the future and 25% would consider?IUD in the future if they knew more about them. Insurance and financial constraints were cited as barriers to IUD use. 4% of the sample reported that they had used an IUD previously and were unhappy with it due to pain and discomfort. 18% would not consider an IUD because they had heard about side effects. 68%?of the surveyed sample reported unintended pregnancies. Conclusion: The two most common barriers to IUD use in this patient population was lack of knowledge?and concern about side effects. Increasing patients’ knowledge of IUDs has the potential to increase IUD utilization in this clinic population which reported a 68% rate of unintended pregnancy.
文摘Intraunterine device (IUD) is a safe, effective and feasible method used for reversible contraception worldwide. Transvesical migration of an Intrauterine device (IUD) is a rare complication. We describe a case in whom initially a plain abdominopelvic radiography demonstrated calcified string of an IUD in a 42-year-old woman with recurrent lower urinary symptoms (LUTS) and urinary tract infection since 2 years earlier. The IUD had been inserted 12 years earlier and 3 years after placement of the IUD, the patient experienced an uneventful pregnancy and a successful delivery. Sonographic images and later on the cystoscopic procedure confirmed the diagnosis of transvesical migration of the IUD. The IUD was removed using cystoscopic procedure, leaving no complication.
文摘Objective: To assess levonorgestrel-releasing intrauterine system LNG-IUS (Mirena?) application at caesarean section (CS). Design: Randomized, comparative study. Setting: Department of obstetrics and gynecology in a primary reference hospital at Puebla City, Mexico. Sample: 396 women requiring CS signed informed consent and were randomly allocated to the post-placental application of LNG-IUS (198) or Copper T 380 A (198). Methods: Follow up visits at 6 weeks, and 6 and 12 months were performed. Main Outcomes Measures: IUDs expulsion, maternal and babies’ health conditions, breastfeeding and menstrual patterns, adverse effects and pregnancies. Differences between groups were analyzed by Fisher and X2 tests, Odds ratios, relative risk and 95% confidence limits, as appropriate. Results: After one year of follow up, no pregnancies were reported. The IUD expulsion rate was 4.5% in each group. LNG-IUS users had a higher incidence of amenorrhea (OR 2.5 95% CI 2.2 - 3) and menstrual patterns significantly brief and lighter than Copper T 380 A (p < 0.001) with lower incidence of dysmenorrhea (OR 0.1 95% CI 0.04 - 0.2). No detrimental effects of LNG-IUS on breastfeeding was observed and interestingly babies weights of LNG-IUS users was slightly above the average for age compared with Copper T 380 A users. This was probably related with a major proportion of women with normal ferritin serum levels (94% vs 68%) leading to better mother’s general condition. Conclusions: LNG-IUS inserted during CS provides high efficacy contraception with additional benefits, mainly reducing menstrual bleeding and doing so, faster recovery of ferrous homeostasis after CS.
文摘AIM: To review the safety(infection, perforation) andefficacy(expulsion, continuation rates, pregnancy) of intrauterine device(IUD) insertion in the postpartum period. METHODS: MEDLINE, Pub Med and Google Scholar were searched for randomized controlled trials and prospective cohort studies of IUD insertions at different times during the postpartum period. Time of insertion during the postpartum period was documented specifically, immediate post placenta period(within 10 min), early post placenta period(10 min to 72 h), and delayed/interval period(greater than 6 wk). Other study variables included mode of delivery, vaginal vs cesarean, manual vs use of ring forceps to insert the IUD. RESULTS: IUD insertion in the immediate postpartum(within 10 min of placental delivery), early postpartum(10 min up to 72 h) and Interval/Delayed(6 wk onward) were found to be safe and efficacious. Expulsion rates were found to be highest in the immediate postpartum groups ranging from 14% to 27%. Immediate post placental insertion found to have expulsion rates that ranged from 3.6% to 16.2%. Expulsion rate was significantly higher after insertion following vaginal vs cesarean delivery. The rates of infection, perforation and unplanned pregnancy following postpartum IUD insertion are low. Method of insertion such as with ring forceps, by hand, or another placement method unique to the type of IUD did not show any significant difference in expulsion rates. Uterine perforations are highest in the delayed/interval IUD insertion groups.Breastfeeding duration and infant development are not affected by delayed/interval insertion of the nonhormonal(copper) IUD or the Levonorgestrel IUD. Timing of the Levonorgestrel IUD insertion may affect breastfeeding. CONCLUSION: IUD insertion is safe and efficacious during the immediate postpartum, early postpartum and delayed postpartum periods. Expulsion rates are highest after vaginal delivery and when inserted during the immediate postpartum period. IUD associated infection rates were not increased by insertion during the postpartum period over interval insertion rates.There is no evidence that breastfeeding is negatively affected by postpartum insertion of copper or hormonesecreting IUD. Although perforation rates were higher when inserted after lactation was initiated. Randomized controlled trials are needed to further elucidate the consequence of lactation on postpartum insertion. Despite the concerns regarding expulsion, perforation and breastfeeding, current evidence indicates that a favorable risk benefit ratio in support of postpartum IUD insertion. This may be particularly relevant for women for whom barriers exist in achieving desired pregnancy spacing.
文摘Three hundred and eighty four women in Shanghai who delivered vaginally and chose IUD for contraception received the copper T 380A IUD inserted vaginally within 10 min after delivery of the placenta(i.e.,immediate postplacental insertion, IPPI). Among them, 98.70% were primipara. The women were randomly divided into two groups: IUD inserted by hand and IUD insreted by ring forceps. Using Life Table Method and χ 2 test, expulsion and other discontinuation rates were compared at 6, 12, 24, and 36 months post insertion between these two different groups. No uterine perforation, infection or prolonged period of lochia occurred in the 384 cases. Expulsions were the main reason for discontinuation. From 6 months to 36 months, the gross cumulative rates of all discontinuation events (expulsion, pregnancy, removal for bleeding/pain, etc.) were not statistically significantly different (P>0.05). The results suggest that these two different insertion techniques do not significantly affect discontinuation rate in vaginal IPPI using the TCu 380 A, which appears to be suitable for postpartum insertion in Chinese women. Other relevant issues, such as breast feeding and IUD position in uterine cavity, are also analyzed and discussed in this paper.
文摘Setting: Provincial General Reference Hospital of Bukavu, General Reference Hospital of Panzi, General Reference Hospital of Ciriri, General Reference Hospital of Nyatende and Biopharm Hospital Center. Objective: Contribute to the improvement of the anesthetic ECP of patients benefiting from MVA for incomplete abortion, Describe the methodology used for adoption of the dosage formula in Anesthesia for MVA, present the mathematical demonstration leading to the dosage formula in anesthesia for MVA. Materials and Methods: Our study was descriptive by mathematical demonstration of obtaining the equilibrium constant of the dosage formula of bipuvacaine 0.1% and Fentanyl 50 µg% adapted to the weight and specific size of patients treated anesthetically in MVA cases for incomplete abortion. We also carried out an operational research by first determining the interval where our equilibrium constant is included and secondly by means of the ends of the intervals found correlated to the ends of intervals of possible weights and sizes in the being normal human female of childbearing age to arrive at the real numerical value of the equilibrium constant of the BUKAVU Dosage Formula in the case of anesthesia for MVA during the management of incomplete abortions. Results: TWO-STAGE OPERATIONAL RESEARCH: • Determination of the interval where the equilibrium constant x = −0.95 x x by crossing the means between the extremes of volumes of anesthetic drugs giving a satisfactory sensory block without hemodynamic disturbance and the extremes of normal weight and height for women of childbearing age. We ended up with X = 0.37. Conclusion: At the end of our study which had the general objectives of contributing to the improvement of the anesthetic PEC of patients receiving MVA for incomplete abortion and specific objectives of describing the methodology used for adoption of the dosage formula in Anesthesia for MVA and present the mathematical demonstration which resulted in the dosage formula in nesthesia for MVA, it appears that the dosage formula of Bukavu, in case of intrathecal spinal analgesia of MVA for incomplete abortion provides precision on the specificity of the doses of bipuvacaine hypobarre 0.1% and Fentanyl 50 µg% reported to each patient according to her weight and height. Its application could therefore reduce morbidity and mortality and improve patient-practitioner comfort in the event of MVA for incomplete abortion following the dosage precision it provides.
基金Project supported by the National Key Research and Development Program of China(Grant No.2018YFE0303105)the Fundamental Research Funds for the Central Universities(Grant No.2022FRFK060021)the National MCF Energy Research and Development Program(Grant No.2019YFE03080300).
文摘The HIT-PSI is a linear plasma device built for physically simulating the high heat flux environment of future reactor divertors to test/develop advanced target plate materials.In this study,the geometry-modified SOLPS-ITER program is employed to examine the effects of the magnetic field strength and neutral pressure in the device on the heat flux experienced by the target plate of the HIT-PSI device.The findings of the numerical simulation indicate a positive correlation between the magnetic field strength and the heat flux density.Conversely,there is a negative correlation observed between the heat flux density and the neutral pressure.When the magnetic field strength at the axis exceeds 1 tesla and the neutral pressure falls below 10 Pa,the HIT-PSI has the capability to attain a heat flux of 10 MW·m-2 at the target plate.The simulation results offer a valuable point of reference for subsequent experiments at HIT-PSI.
基金supported by the National Natural Science Foundation of China(52322210,52172144,22375069,21825103,and U21A2069)National Key R&D Program of China(2021YFA1200501)+1 种基金Shenzhen Science and Technology Program(JCYJ20220818102215033,JCYJ20200109105422876)the Innovation Project of Optics Valley Laboratory(OVL2023PY007).
文摘Two-dimensional(2D)materials have attracted tremendous interest in view of the outstanding optoelectronic properties,showing new possibilities for future photovoltaic devices toward high performance,high specific power and flexibility.In recent years,substantial works have focused on 2D photovoltaic devices,and great progress has been achieved.Here,we present the review of recent advances in 2D photovoltaic devices,focusing on 2D-material-based Schottky junctions,homojunctions,2D−2D heterojunctions,2D−3D heterojunctions,and bulk photovoltaic effect devices.Furthermore,advanced strategies for improving the photovoltaic performances are demonstrated in detail.Finally,conclusions and outlooks are delivered,providing a guideline for the further development of 2D photovoltaic devices.
基金supported by a grant of the Ministry of Research,Innovation and Digitization,CNCS–UEFISCDI,project number PNIII-P1-1.1-TE-2021-1110PNCDI III,contract number TE 83/2022,and project number PN-III-P2-2.1-PED-2019-3520PNCDI III,contract number 438PED/2020。
文摘The current investigation offers an innovative synthetic solution regarding electrochromic(EC)and energy storage applications by exploring phenoxazine(POZ)moiety.Subsequently,three POZ-based polymers(polyimide,polyazomethine,and polyamide)were synthesized to ascertain the superior performer.The polyamide exhibited remarkable attributes,including high redox stability during 500 repetitive CVs,optical contrast of 61.98%,rapid response times of 1.02 and 1.38 s for coloring and bleaching,EC efficiency of 280 cm^(2)C^(-1).and decays of the optical density and EC efficiency of only 12.18%and 6.23%after 1000 cycles.Then,the energy storage performance of polyamide PA was tested,for which the following parameters were obtained:74.7 F g^(-1)(CV,scan rate of 10 mV s^(-1))and 118 F g^(-1)(GCD,charging current of 0.1 A g^(-1)).Then,the polyamide was tested in EES devices,which yielded the following EC parameters:an optical contrast of 62.15%,response times of 9.24 and 5.01 s for coloring and bleaching,EC efficiency of 178 cm^(2)C^(-1),and moderate decays of 20.25%and 23.24%for the optical density and EC efficiency after 500 cycles.The energy storage performance included a capacitance of 106 F g^(-1)(CV,scan rate of 0.1 mV s^(-1))and 9.23 F g^(-1)(GCD,charging current of 0.1 A g^(-1)),capacitance decay of 11.9%after500 cycles,and 1.7 V retention after 2 h.Also,two EES devices connected in series powered a 3 V LED for almost 30 s.
基金Project supported by the Special Funding for Talents of Three Gorges University(Grant No.8230202)the National Natural Science Foundation of China(Grant No.12274258)National Key R&D Program of China(Grant No.2016YFA0401003).
文摘Non-magnetic semiconductor materials and their devices have attracted wide attention since they are usually prone to exhibit large positive magnetoresistance(MR)effect in a low static magnetic field environment at room temperature.However,how to obtain a large room-temperature negative MR effect in them remains to be studied.In this paper,by designing an Au/n-Ge:Sb/Au device with metal electrodes located on identical side,we observe an obvious room-temperature negative MR effect in a specific 50 T pulsed high magnetic field direction environment,but not in a static low magnetic field environment.Through the analysis of the experimental measurement of the Hall effect results and bipolar transport theory,we propose that this unconventional negative MR effect is mainly related to the charge accumulation on the surface of the device under the modulation of the stronger Lorentz force provided by the pulsed high magnetic field.This theoretical analytical model is further confirmed by regulating the geometry size of the device.Our work sheds light on the development of novel magnetic sensing,magnetic logic and other devices based on non-magnetic semiconductors operating in pulsed high magnetic field environment.
基金This work is supported by the National Natural Science Foundation of China(No.61904151)the National Key Research and Development Program of China(No.2021YFA1200803)the Joint Research Funds of the Department of Science&Technology of Shaanxi Province and Northwestern Polytechnical University(No.2020GXLH-Z-020).
文摘Atomically thin MoSe_(2) layers,as a core member of the transition metal dichalcogenides(TMDs)family,benefit from their appealing properties,including tunable band gaps,high exciton binding energies,and giant oscillator strengths,thus pro-viding an intriguing platform for optoelectronic applications of light-emitting diodes(LEDs),field-effect transistors(FETs),sin-gle-photon emitters(SPEs),and coherent light sources(CLSs).Moreover,these MoSe_(2) layers can realize strong excitonic emis-sion in the near-infrared wavelengths,which can be combined with the silicon-based integration technologies and further encourage the development of the new generation technologies of on-chip optical interconnection,quantum computing,and quantum information processing.Herein,we overview the state-of-the-art applications of light-emitting devices based on two-dimensional MoSe_(2) layers.Firstly,we introduce recent developments in excitonic emission features from atomically thin MoSe_(2) and their dependences on typical physical fields.Next,we focus on the exciton-polaritons and plasmon-exciton polaritons in MoSe_(2) coupled to the diverse forms of optical microcavities.Then,we highlight the promising applications of LEDs,SPEs,and CLSs based on MoSe_(2) and their heterostructures.Finally,we summarize the challenges and opportunities for high-quality emis-sion of MoSe_(2) and high-performance light-emitting devices.
基金the National Natural Science Foundation of China(11875138,52077095).
文摘High-performance ion-conducting hydrogels(ICHs)are vital for developing flexible electronic devices.However,the robustness and ion-conducting behavior of ICHs deteriorate at extreme tempera-tures,hampering their use in soft electronics.To resolve these issues,a method involving freeze–thawing and ionizing radiation technology is reported herein for synthesizing a novel double-network(DN)ICH based on a poly(ionic liquid)/MXene/poly(vinyl alcohol)(PMP DN ICH)system.The well-designed ICH exhibits outstanding ionic conductivity(63.89 mS cm^(-1) at 25℃),excellent temperature resistance(-60–80℃),prolonged stability(30 d at ambient temperature),high oxidation resist-ance,remarkable antibacterial activity,decent mechanical performance,and adhesion.Additionally,the ICH performs effectively in a flexible wireless strain sensor,thermal sensor,all-solid-state supercapacitor,and single-electrode triboelectric nanogenerator,thereby highlighting its viability in constructing soft electronic devices.The highly integrated gel structure endows these flexible electronic devices with stable,reliable signal output performance.In particular,the all-solid-state supercapacitor containing the PMP DN ICH electrolyte exhibits a high areal specific capacitance of 253.38 mF cm^(-2)(current density,1 mA cm^(-2))and excellent environmental adaptability.This study paves the way for the design and fabrication of high-performance mul-tifunctional/flexible ICHs for wearable sensing,energy-storage,and energy-harvesting applications.
文摘Tunable Airy beams with controllable propagation trajectories have sparked interest in various fields,such as optical manipulation and laser fabrication.Existing research approaches encounter challenges related to insufficient compactness and integration feasibility,or they require enhanced tunability to enable real-time dynamic manipulation of the propagation trajectory.In this work,we present a novel method that utilizes a dual metasurface system to surpass these limitations,significantly enhancing the practical potential of the Airy beam.Our approach involves encoding a cubic phase profile and two off-axis Fresnel lens phase profiles across the two metasurfaces.The validity of the proposed strategy has been confirmed through simulation and experimental results.The proposed meta-device addresses the existing limitations and lays the foundation for broadening the applicability of Airy beams across diverse domains,encompassing light-sheet microscopy,laser fabrication,optical tweezers,etc.
基金This work is supported by Demonstration of Scientific and Technology Achievements Transform in Sichuan Province under Grant 2022ZHCG0036National Natural Science Foundation of China(62002047).
文摘Identifying a device and detecting a change in its position is critical for secure devices management in the Internet of Things(IoT).In this paper,a device management system is proposed to track the devices by using audio-based location distinction techniques.In the proposed scheme,traditional cryptographic techniques,such as symmetric encryption algorithm,RSA-based signcryption scheme,and audio-based secure transmission,are utilized to provide authentication,non-repudiation,and confidentiality in the information interaction of the management system.Moreover,an audio-based location distinction method is designed to detect the position change of the devices.Specifically,the audio frequency response(AFR)of several frequency points is utilized as a device signature.The device signature has the features as follows.(1)Hardware Signature:different pairs of speaker and microphone have different signatures;(2)Distance Signature:in the same direction,the signatures are different at different distances;and(3)Direction Signature:at the same distance,the signatures are different in different directions.Based on the features above,amovement detection algorithmfor device identification and location distinction is designed.Moreover,a secure communication protocol is also proposed by using traditional cryptographic techniques to provide integrity,authentication,and non-repudiation in the process of information interaction between devices,Access Points(APs),and Severs.Extensive experiments are conducted to evaluate the performance of the proposed method.The experimental results show that the proposedmethod has a good performance in accuracy and energy consumption.
