Purpose: Needle-stick injury (NSI) is one of the most potential occupational hazards for healthcare workers because of the transmission of blood-borne pathogens. As per recent data, around 30 lakh healthcare workers s...Purpose: Needle-stick injury (NSI) is one of the most potential occupational hazards for healthcare workers because of the transmission of blood-borne pathogens. As per recent data, around 30 lakh healthcare workers sustain Needle stick injuries each year. This study was conducted to assess healthcare workers’ knowledge, attitude and practices regarding needle stick injury. Materials & Methods: A cross-sectional study was conducted in a Tertiary Care Hospital over the period of 3 months. The study population consisted of Intern Doctors, Post Graduate resident Doctors, Staff Nurses, laboratory technicians of Government Medical College and New Civil Hospital, Surat (n = 300). The data were collected using a self-administered questionnaire via the means of Google Forms. Questionnaire was made with prior review literature. The data obtained were entered and analysed in Microsoft Excel. Results: The prevalence of NSI in our study was 46%, with a higher prevalence among the PG residents (72%). Overall scores regarding knowledge and attitude were better in PG residents (knowledge score > 7 in 71% and Attitude Score > 7 in 68% of PG Residents). Even though the PG residents scored highest in the knowledge category, the majority of them suffered needle stick injuries as a result of poor practice scores. Among those who had NSI (n = 139/300), 70% of study participants had superficial injuries, only 9% reported the incident, 18% got medical attention within 2 hours of the incident, and 7% followed up to recheck their viral markers status. Most incidents of NSI were due to hypodermic needles while recapping needles. Conclusion: Exposure to needle stick injuries and their underreporting remains a common problem. It is imperative that healthcare workers receive regular training on the proper handling of sharp objects. We can also draw the conclusion that preventing NSIs requires putting knowledge into practice.展开更多
To investigate the freeze-thaw(F-T)damages and failure characteristics of rock mass with arc-shaped joints in cold regions,three types of cement mortar specimens with different central angles and prefabricated arc-sha...To investigate the freeze-thaw(F-T)damages and failure characteristics of rock mass with arc-shaped joints in cold regions,three types of cement mortar specimens with different central angles and prefabricated arc-shaped flaws are subjected to uniaxial compressive tests under different F-T cycles.Experimental observations show that the uniaxial compressive strength of specimens are significantly influenced by F-T cycles and their failure modes are mainly affected by the central angleαof the prefabricated flaws.Unlike the specimens with a central angle of 60°,the specimens with a central angle of 120°and 180°have greater curvature of flaws,so tensile cracks occur in the arc-top area of their prefabricated flaws.According to experimental images observed by environmental scanning electron microscope(ESEM),as the number of F-T cycles increases,the deterioration effect of the specimen becomes more obvious,which is specifically reflected in the increase of the mass loss,peak stress loss,and damage variables as a power function,and the peak strain decreases as a quadratic polynomial.According to numerical results using two-dimensional particle flow code(PFC2D),it is found that F-T cycles cause more damage to the specimen in the early stages than in the later ones.The area of the concentrated compressive stress zone in the middle is decreased due to the increased number of F-T cycles,while the area of the surrounding tensile-shear stress zone is increased.The models appear different failure modes due to the release of concentrated stress in different tensile-shear zones.展开更多
MXene,a transition metal carbide/nitride,has been prominent as an ideal electrochemical active material for supercapacitors.However,the low MXene load limits its practical applications.As environmental concerns and su...MXene,a transition metal carbide/nitride,has been prominent as an ideal electrochemical active material for supercapacitors.However,the low MXene load limits its practical applications.As environmental concerns and sustainable development become more widely recognized,it is necessary to explore a greener and cleaner technology to recycle textile by-products such as cotton.The present study proposes an effective 3D fabrication method that uses MXene to fabricate waste denim felt into ultralight and flexible supercapacitors through needling and carbonization.The 3D structure provided more sites for loading MXene onto Z-directional fiber bundles,resulting in more efficient ion exchange between the electrolyte and electrodes.Furthermore,the carbonization process removed the specific adverse groups in MXenes,further improving the specific capacitance,energy density,power density and electrical conductivity of supercapacitors.The electrodes achieve a maximum specific capacitance of 1748.5 mF cm-2 and demonstrate remarkable cycling stability maintaining more than 94%after 15,000 galvanostatic charge/discharge cycles.Besides,the obtained supercapacitors present a maximum specific capacitance of 577.5 mF cm^(-2),energy density of 80.2μWh cm^(-2)and power density of 3 mW cm^(-2),respectively.The resulting supercapacitors can be used to develop smart wearable power devices such as smartwatches,laying the foundation for a novel strategy of utilizing waste cotton in a high-quality manner.展开更多
In the northern part of the Ordos Basin, there is a 325 km long arc-shaped Langshan uplift and a 15 km-deep Linhe Trench in front of Langshan, which are rare geological phenomena for which origins no one has explained...In the northern part of the Ordos Basin, there is a 325 km long arc-shaped Langshan uplift and a 15 km-deep Linhe Trench in front of Langshan, which are rare geological phenomena for which origins no one has explained. This article comprehensively analyzes the research achievements over the past 40 years of geology, geomorphology, seismic exploration, paleogeography, and oil and gas exploration in the Ordos Basin and Langshan. It recognizes that the northern part of the Ordos Basin experienced a meteorite impact in the Late Cretaceous period. The impact pushed the block northwest ward, subducting after colliding with igneous rocks in the north. This sudden event formed a clear arc-shaped mountain zone in the north and a wedge-shaped trench in front of the mountain. The chaotic layers, prolonged and continuous faults, and numerous thrust layers in the Langshan, a negative anomaly area in the center of the northern Ordos, abnormal orientation of crystalline basement structures in the north of Ordos, Moho uplift, and distribution of meteorite fragments in the northwest of Langshan, all of these geological phenomena support the occurrence of the meteorite impact event, forming the arc-shaped Langshan and the Trench.展开更多
Needle chlorosis(NC)in Pinus taeda L.systems in Brazil becomes more frequent after second and third harvest rotation cycles.In a study to identify factors contributing to yellowing needle chorosis(YNC),trees were grow...Needle chlorosis(NC)in Pinus taeda L.systems in Brazil becomes more frequent after second and third harvest rotation cycles.In a study to identify factors contributing to yellowing needle chorosis(YNC),trees were grown in soils originating from contrasting parent materials,and soils and needles(whole,green and chlorotic portions)from 1-and 2-year-old branches and the first and second needle flush release at four sites with YNC on P.taeda were analyzed for various elements and properties.All soils had very low base levels(Ca^(2+),Mg^(2+)and K^(+))and P,suggesting a possible lack of multiple elements.YNC symptoms started at needle tips,then extended toward the needle base with time.First flush needles had longer portions with YNC than second flush needles did.Needles from the lower crown also had more symptoms along their length than those higher in the canopy.Symptoms were similar to those reported for Mg.In chlorotic portions,Mg and Ca concentrations were well below critical values;in particular,Mg levels were only one third of the critical value of 0.3 g kg^(-1).Collectively,results suggest that Mg deficiency is the primary reason for NC of P.taeda in various parent soils in Brazil.展开更多
In this paper,self-designed multi-hollow needle electrodes are used as a high-voltage electrode in a packed bed dielectric barrier discharge reactor to facilitate fast gas flow through the active discharge area and ac...In this paper,self-designed multi-hollow needle electrodes are used as a high-voltage electrode in a packed bed dielectric barrier discharge reactor to facilitate fast gas flow through the active discharge area and achieve large-volume stable discharge.The dynamic characteristics of the plasma,the generated active species,and the energy transfer mechanisms in both positive discharge(PD)and negative discharge(ND)are investigated by using fast-exposure intensified charge coupled device(ICCD)images and time-resolved optical emission spectra.The experimental results show that the discharge intensity,number of discharge channels,and discharge volume are obviously enhanced when the multi-needle electrode is replaced by a multihollow needle electrode.During a single voltage pulse period,PD mainly develops in a streamer mode,which results in a stronger discharge current,luminous intensity,and E/N compared with the diffuse mode observed in ND.In PD,as the gap between dielectric beads changes from 0 to250μm,the discharge between the dielectric bead gap changes from a partial discharge to a standing filamentary micro-discharge,which allows the plasma to leave the local area and is conducive to the propagation of surface streamers.In ND,the discharge only appears as a diffusionlike mode between the gap of dielectric beads,regardless of whether there is a discharge gap.Moreover,the generation of excited states N_(2)^(+)(B^(2)∑_(u)^(+))and N2(C^(3)Π_(u))is mainly observed in PD,which is attributed to the higher E/N in PD than that in ND.However,the generation of the OH(A^(2)∑^(+))radical in ND is higher than in PD.It is not directly dominated by E/N,but mainly by the resonant energy transfer process between metastable N_(2)(A^(3)∑_(u)^(+))and OH(X^(2)Π).Furthermore,both PD and ND demonstrate obvious energy relaxation processes of electron-to-vibration and vibration-to-vibration,and no vibration-to-rotation energy relaxation process is observed.展开更多
In the early 20th century,French vice-consul George Souliéde Morant encountered acupuncture during his visit to China,and then brought it back to France.After more than a century,his collection was transported fr...In the early 20th century,French vice-consul George Souliéde Morant encountered acupuncture during his visit to China,and then brought it back to France.After more than a century,his collection was transported from Paris,France to Kunming,China,and later recognized as a Chinese national third-class precious cultural heritage.Currently housed in the Museum of Western Studies on Chinese Medicine at Yunnan University of Chinese Medicine,this set of instruments includes one needle holder converted from a fan-shaped holder,ten acupuncture needles,and eleven paper tags handwritten in English with names of diseases and body parts.This article attempts to present the foundational information and historical significance of this collection of this set of late Qing dynasty acupuncture instruments by reviewing the collection and related research on acupuncture instruments,consulting acupuncture professionals,measuring the detailed information of the set of instruments,and employing a method of translating and summarizing the content of the attached tags.展开更多
The development of a nanosecond discharge in a pin-to-pin gap filled with air at atmospheric pressure has been studied with high temporal and spatial resolutions from a breakdown start to the spark decay.Positive and ...The development of a nanosecond discharge in a pin-to-pin gap filled with air at atmospheric pressure has been studied with high temporal and spatial resolutions from a breakdown start to the spark decay.Positive and negative nanosecond voltage pulses with an amplitude of tens of kilovolts were applied.Time-resolved images of the discharge development were taken with a fourchannel Intensified Charge Coupled Device(ICCD)camera.The minimum delay between the camera channels could be as short as≈0.1 ns.This made it possible to study the gap breakdown process with subnanosecond resolution.It was observed that a wide-diameter streamer develops from the high-voltage pointed electrode.The ionization processes near the grounded pin electrode started when the streamer crossed half of the gap.After bridging the gap by the streamer,a diffuse discharge was formed.The development of spark leaders from bright spots on the surface of the pointed electrodes was observed at the next stage.It was found that the rate of development of the spark leader is an order of magnitude lower than that of the wide-diameter streamer.Long thin luminous tracks were observed against the background of a discharge plasma glow.It has been established that the tracks are adjacent to brightly glowing spots on the electrodes and are associated with the flight of small particles.展开更多
BACKGROUND The overlap of imaging manifestations among distinct splenic lesions gives rise to a diagnostic dilemma.Consequently,a definitive diagnosis primarily relies on his-tological results.The ultrasound(US)-guide...BACKGROUND The overlap of imaging manifestations among distinct splenic lesions gives rise to a diagnostic dilemma.Consequently,a definitive diagnosis primarily relies on his-tological results.The ultrasound(US)-guided coaxial core needle biopsy(CNB)not only procures sufficient tissue to help clarify the diagnosis,but reduces the incidence of puncture-related complications.CASE SUMMARY A 41-year-old female,with a history of pulmonary tuberculosis,was admitted to our hospital with multiple indeterminate splenic lesions.Gray-scale ultrasono-graphy demonstrated splenomegaly with numerous well-defined hypoechoic ma-sses.Abdominal contrast-enhanced computed tomography(CT)showed an en-larged spleen with multiple irregular-shaped,peripherally enhancing,hypodense lesions.Positron emission CT revealed numerous abnormal hyperglycemia foci.These imaging findings strongly indicated the possibility of infectious disease as the primary concern,with neoplastic lesions requiring exclusion.To obtain the precise pathological diagnosis,the US-guided coaxial CNB of the spleen was ca-rried out.The patient did not express any discomfort during the procedure.CONCLUSION Percutaneous US-guided coaxial CNB is an excellent and safe option for obtaining precise splenic tissue samples,as it significantly enhances sample yield for exact pathological analysis with minimum trauma to the spleen parenchyma and sur-rounding tissue.展开更多
BACKGROUND Acute injuries to the tibiofibular syndesmosis,often associated with high ankle sprains or malleolar fractures,require precise diagnosis and treatment to prevent long-term complications.This case report exp...BACKGROUND Acute injuries to the tibiofibular syndesmosis,often associated with high ankle sprains or malleolar fractures,require precise diagnosis and treatment to prevent long-term complications.This case report explores the use of needle arthroscopy as a minimally invasive technique for the repair of tibiofibular syndesmosis injuries.CASE SUMMARY We report on a 40-year-old male patient who presented with a trimalleolar fracture and ankle subluxation following a high ankle sprain.Due to significant swelling and poor soft tissue quality,initial management involved external stabilization.Subsequently,needle arthroscopy was employed to assess and treat the tibiofibular syndesmosis injury.The procedure,performed under spinal anesthesia and fluoroscopic control,included nanoscopic evaluation of the ankle joint and reduction of the syndesmosis using a suture button.Follow-up assessments showed significant improvement in pain levels,range of motion,and functional scores.At 26 weeks post-procedure,the patient achieved full range of motion and pain-free status.Needle arthroscopy offers a promising alternative for the management of acute tibiofibular syndesmosis injuries,combining diagnostic and therapeutic capabilities with minimal invasiveness.CONCLUSION This technique may enhance clinical outcomes and reduce recovery times,warranting further investigation and integration into clinical practice.展开更多
Background: As the population age structure gradually ages, more and more elderly people were found to have pulmonary nodules during physical examinations. Most elderly people had underlying diseases such as heart, lu...Background: As the population age structure gradually ages, more and more elderly people were found to have pulmonary nodules during physical examinations. Most elderly people had underlying diseases such as heart, lung, brain and blood vessels and cannot tolerate surgery. Computed tomography (CT)-guided percutaneous core needle biopsy (CNB) was the first choice for pathological diagnosis and subsequent targeted drugs, immune drugs or ablation treatment. CT-guided percutaneous CNB requires clinicians with rich CNB experience to ensure high CNB accuracy, but it was easy to cause complications such as pneumothorax and hemorrhage. Three-dimensional (3D) printing coplanar template (PCT) combined with CT-guided percutaneous pulmonary CNB biopsy has been used in clinical practice, but there was no prospective, randomized controlled study. Methods: Elderly patients with lung nodules admitted to the Department of Oncology of our hospital from January 2019 to January 2023 were selected. A total of 225 elderly patients were screened, and 30 patients were included after screening. They were randomly divided into experimental group (Group A: 30 cases) and control group (Group B: 30 cases). Group A was given 3D-PCT combined with CT-guided percutaneous pulmonary CNB biopsy, Group B underwent CT-guided percutaneous pulmonary CNB. The primary outcome measure of this study was the accuracy of diagnostic CNB, and the secondary outcome measures were CNB time, number of CNB needles, number of pathological tissues and complications. Results: The diagnostic accuracy of group A and group B was 96.67% and 76.67%, respectively (P = 0.026). There were statistical differences between group A and group B in average CNB time (P = 0.001), number of CNB (1 vs more than 1, P = 0.029), and pathological tissue obtained by CNB (3 vs 1, P = 0.040). There was no statistical difference in the incidence of pneumothorax and hemorrhage between the two groups (P > 0.05). Conclusions: 3D-PCT combined with CT-guided percutaneous CNB can improve the puncture accuracy of elderly patients, shorten the puncture time, reduce the number of punctures, and increase the amount of puncture pathological tissue, without increasing pneumothorax and hemorrhage complications. We look forward to verifying this in a phase III randomized controlled clinical study. .展开更多
Introduction: The frequent late-stage diagnosis of chronic kidney disease (CKD) constrains the treatment choices for nephrologists. Renal biopsy (RB) is crucial for accurately identifying renal lesions. This key nephr...Introduction: The frequent late-stage diagnosis of chronic kidney disease (CKD) constrains the treatment choices for nephrologists. Renal biopsy (RB) is crucial for accurately identifying renal lesions. This key nephrological procedure, however, is invasive and not without potential complications. The purpose of this study was to evaluate the indications, frequency, and histological lesion profiles of renal biopsies in Togo. Materials and Methods: We conducted a descriptive cross-sectional study encompassing all renal biopsies performed in Togo from the inception of nephrology services to the present. Data were compiled from the medical records of the patients. Results: From 2015 to 2023, 68 high-quality renal biopsies were executed in Togo. The patients had an average age of 30.6 years, with a predominance of males (69.1%). The most common indication was nephrotic syndrome, accounting for 66.2% of cases. Histologically, glomerulopathies were predominant, representing 61.8% of lesions, followed by vascular nephropathies (25%) and tubulointerstitial nephropathies (13.2%). The most frequently observed primary glomerulopathy was focal segmental glomerulosclerosis (FSGS). Gross hematuria was the sole complication, occurring in 1.4% of the cases. Conclusion: RB is an evolving practice in Togo. Glomerulopathies are the most commonly observed lesions. The histological categorization of renal lesions is vital for clinicians in their diagnostic reasoning and approach.展开更多
[Objectives]To observe the clinical effect of the lotus needle cupping therapy for removing blood stasis in Zhuang medicine in treating PHNand its influence on inflammatory factors.[Methods]96 patients with PHN were r...[Objectives]To observe the clinical effect of the lotus needle cupping therapy for removing blood stasis in Zhuang medicine in treating PHNand its influence on inflammatory factors.[Methods]96 patients with PHN were randomly divided into three groups:lotus nee-dle cupping therapy group,TCM surrounding acupuncture group and gabapentin group.Venous blood and acupoint blood were collected at 0,21 and 42 d of treatment,and the expression levels of 5-HT,SP and CGRPinflammatory mediators were detected before and after treatment.The changes of VAS scores before,during and after treatment and the clinical efficacy were observed.[Results]The total effective rate of the lotus needle cupping group was 87.50%,which was better than that of the TCM acupuncture group(81.25%)and the gabapentin group(62.50%);after treatment,the VAS scores and the expression of inflammatory mediators in the three groups of patients were lower than those before treatment,and the decrease was more significant in the treatment group(P<0.05).[Conclusions]The lotus needle cupping therapy for removing blood stasis in Zhuang medicine is effective in treating PHN,and its mechanism is to reduce the release of inflammatory media-tors,reduce hyperalgesia,relieve pain and improve the quality of life of patients.展开更多
MANCHESTER,UK-Having successfully demonstrated its WebSpector automated fabric inspection system detecting faults on camouflage fabrics at speeds of up to 100metres a minute during ITMA 2023,BTMA member Shelton Vision...MANCHESTER,UK-Having successfully demonstrated its WebSpector automated fabric inspection system detecting faults on camouflage fabrics at speeds of up to 100metres a minute during ITMA 2023,BTMA member Shelton Vision has secured an unprecedented number of new orders in many fields of the textile industry.The company has subsequently been recruiting additional staff in order to beef up its operations to meet delivery times and to grow capacity for the ongoing increased demand.展开更多
Dear Editor,Submacular hemorrhage(SMH)is the accumulation of blood in the macular region caused by changes in retinal or choroidal circulation[1].SMH may be caused by age-related macular degeneration(AMD),pathological...Dear Editor,Submacular hemorrhage(SMH)is the accumulation of blood in the macular region caused by changes in retinal or choroidal circulation[1].SMH may be caused by age-related macular degeneration(AMD),pathological myopia,polypoid choroidal angiopathy(PCV)or retinal macroaneurysm[2].展开更多
BACKGROUND Genetic tests are increasingly performed for the management of unresectable pancreatic cancer.For genotyping aimed samples current guidelines recommend using core specimens,although based on moderate qualit...BACKGROUND Genetic tests are increasingly performed for the management of unresectable pancreatic cancer.For genotyping aimed samples current guidelines recommend using core specimens,although based on moderate quality evidence.However,in clinical practice among the endoscopic ultrasound(EUS) guided tissue acquisition methods,fine needle aspiration(FNA) is the most widely performed.AIM To assess the adequacy for next generation sequencing(NGS) of the DNA yielded from EUS-FNA pancreatic adenocarcinoma(PDAC) samples.METHODS Between November 2018 and December 2021,105 patients with PDAC confirmed by EUS-FNA were included in the study at our tertiary gastroenterology center.Either 22 gauge(G) or 19G FNA needles were used.One pass was dedicated to DNA extraction.DNA concentration and purity(A260/280,A260/230) were assessed by spectrophotometry.We assessed the differences in DNA parameters according to needle size and tumor characteristics(size,location) and the adequacy of the extracted DNA for NGS(defined as A260/280 ≥ 1.7,and DNA yield:≥ 10 ng for amplicon based NGS,≥ 50 ng for whole exome sequencing [WES],≥ 100 ng for whole genome sequencing [WGS]) by analysis of variance and ttest respectively.Moreover,we compared DNA purity parameters across the different DNA yield categories.RESULTS Our cohort included 49% male patients,aged 67.02 ± 8.38 years.The 22G needle was used in 71%of the cases.The DNA parameters across our samples varied as follows:DNA yield:1289 ng(inter quartile range:534.75-3101),A260/280 = 1.85(1.79-1.86),A260/230 = 2.2(1.72-2.36).DNA yield was > 10 ng in all samples and > 100 ng in 93% of them(one sample < 50 ng).There were no significant differences in the concentration and A260/280 between samples by needle size.Needle size was the only independent predictor of A260/230 which was higher in the 22G samples(P =0.038).NGS adequacy rate was 90% for 19G samples regardless of NGS type,and for 22G samples it reached 89% for WGS adequacy and 91% for WES and amplicon based NGS.Samples with DNA yield > 100 ng had significantly higher A260/280(1.89 ± 0.32 vs 1.34 ± 0.42,P = 0.013).Tumor characteristics were not corelated with the DNA parameters.CONCLUSION EUS-FNA PDAC samples yield DNA adequate for subsequent NGS.DNA amount was similar between 22G and 19G FNA needles.DNA purity parameters may vary indirectly with needle size.展开更多
This study proposes a hypodermic needle(HN)as a sorbent holder and an electrospray(ESI)emitter,thus combining extraction and analysis in a single device.A novel nylon 6-cellulose(N6-Cel)composite sorbent is proposed t...This study proposes a hypodermic needle(HN)as a sorbent holder and an electrospray(ESI)emitter,thus combining extraction and analysis in a single device.A novel nylon 6-cellulose(N6-Cel)composite sorbent is proposed to extract methadone from oral fluid samples.The cellulosic substrate provides the composite with high porosity,permitting the flow-through of the sample,while the polyamide contributes to the extraction of the analyte.The low price of the devices(considering the holder and the sorbent)contributes to the affordability of the method,and their small size allows easy transportation,opening the door to on-site extractions.Under the optimum conditions,the analyte can be determined by high-resolution ambient ionization mass spectrometry at a limit of detection(LOD)as low as 0.3 mg/L and precision(expressed as relative standard deviation,RSD)better than 9.3%.The trueness,expressed as relative recovery(RR),ranged from 90%to 109%.As high-resolution mass spectrometers are not available in many laboratories,the method was also adapted to low-resolution spectrometers.In this sense,the direct infusion of the eluates in a triple quadrupole-mass spectrometry provided an LOD of 2.2 mg/L.The RSD was better than 5.3%,and the RR ranged from 96%to 121%.展开更多
The relationship between the microstructure and the practical performance of two different copper-beryllium alloys including their lifetime has been investigated.Herein,two valves made of two different alloys with ver...The relationship between the microstructure and the practical performance of two different copper-beryllium alloys including their lifetime has been investigated.Herein,two valves made of two different alloys with very similar compositions and the same heat treatment methods were investigated by various standard techniques including metallography,X-ray diffraction,chemical composition,microhardness,and thermal conductivity measurements.Although both alloys experienced the same heat-treatment processes,they revealed different thermal and mechanical properties due to the minor difference in their chemical composition.The alloy providing a longer lifetime (40%more) as the tip had a higher thermal conductivity of 280.3 W(m·K)^(-1) (about two times that of the other alloy).Regarding the metallography images and the measured thermal conductivity values of the alloys,the extended lifetime of the nozzle with the optimum performance is ascribed to its biphasic microstructure and the minor grain boundaries and interfacial thermal resistance.And important difference in the chemical composition was investigated in this study.展开更多
Corona discharge, as a common means to obtain non-equilibrium plasma, can generally obtain high-concentration plasma by increasing discharge points to meet production needs. However,the existing numerical simulation m...Corona discharge, as a common means to obtain non-equilibrium plasma, can generally obtain high-concentration plasma by increasing discharge points to meet production needs. However,the existing numerical simulation models used to study multi-point corona discharge are all calculations of small-scale space models, which cannot obtain the distribution characteristics of plasma in large space. Based on our previous research, this paper proposes a hybrid model for studying the distribution of multi-point discharge plasma in large-scale spaces, which divides the computational domain and computes separately with the hydrodynamic model and the ion mobility model. The simulation results are verified by a needle–ball electrode device. Firstly, the electric field distribution and plasma distribution of the needle electrodes with single tip and double tips are compared and discussed. Secondly, the plasma distribution of the needle electrode with the double tip at different voltages is investigated. Both computational and experimental results indicate that the charged particle concentration and current of the needle electrode with double tips are both twice as high as those of the needle electrode with a single tip. This model can extend the computational area of the multi-point corona discharge finite element model to the sub-meter(25 cm) or meter level, which provides an effective means to study the plasma distribution generated by multiple discharge points in large-scale space.展开更多
文摘Purpose: Needle-stick injury (NSI) is one of the most potential occupational hazards for healthcare workers because of the transmission of blood-borne pathogens. As per recent data, around 30 lakh healthcare workers sustain Needle stick injuries each year. This study was conducted to assess healthcare workers’ knowledge, attitude and practices regarding needle stick injury. Materials & Methods: A cross-sectional study was conducted in a Tertiary Care Hospital over the period of 3 months. The study population consisted of Intern Doctors, Post Graduate resident Doctors, Staff Nurses, laboratory technicians of Government Medical College and New Civil Hospital, Surat (n = 300). The data were collected using a self-administered questionnaire via the means of Google Forms. Questionnaire was made with prior review literature. The data obtained were entered and analysed in Microsoft Excel. Results: The prevalence of NSI in our study was 46%, with a higher prevalence among the PG residents (72%). Overall scores regarding knowledge and attitude were better in PG residents (knowledge score > 7 in 71% and Attitude Score > 7 in 68% of PG Residents). Even though the PG residents scored highest in the knowledge category, the majority of them suffered needle stick injuries as a result of poor practice scores. Among those who had NSI (n = 139/300), 70% of study participants had superficial injuries, only 9% reported the incident, 18% got medical attention within 2 hours of the incident, and 7% followed up to recheck their viral markers status. Most incidents of NSI were due to hypodermic needles while recapping needles. Conclusion: Exposure to needle stick injuries and their underreporting remains a common problem. It is imperative that healthcare workers receive regular training on the proper handling of sharp objects. We can also draw the conclusion that preventing NSIs requires putting knowledge into practice.
基金Funded by the National Key Research and Development Program of China(No.2023YFB260012602)the Shandong Provincial Natural Science Foundation(No.ZR2023ME208)。
文摘To investigate the freeze-thaw(F-T)damages and failure characteristics of rock mass with arc-shaped joints in cold regions,three types of cement mortar specimens with different central angles and prefabricated arc-shaped flaws are subjected to uniaxial compressive tests under different F-T cycles.Experimental observations show that the uniaxial compressive strength of specimens are significantly influenced by F-T cycles and their failure modes are mainly affected by the central angleαof the prefabricated flaws.Unlike the specimens with a central angle of 60°,the specimens with a central angle of 120°and 180°have greater curvature of flaws,so tensile cracks occur in the arc-top area of their prefabricated flaws.According to experimental images observed by environmental scanning electron microscope(ESEM),as the number of F-T cycles increases,the deterioration effect of the specimen becomes more obvious,which is specifically reflected in the increase of the mass loss,peak stress loss,and damage variables as a power function,and the peak strain decreases as a quadratic polynomial.According to numerical results using two-dimensional particle flow code(PFC2D),it is found that F-T cycles cause more damage to the specimen in the early stages than in the later ones.The area of the concentrated compressive stress zone in the middle is decreased due to the increased number of F-T cycles,while the area of the surrounding tensile-shear stress zone is increased.The models appear different failure modes due to the release of concentrated stress in different tensile-shear zones.
基金The authors acknowledge the financial support from the National Natural Science Foundation of China(Nos.52073224,32201491)the Textile Vision Basic Research Program of China(No.J202110)+3 种基金the Scientific Research Project of Shaanxi Provincial Education Department,China(No.22JC035)the Advanced Manufacturing Technology Program of Xi’an Science and Technology Bureau,China(No.21XJZZ0019)the Research Fund for the Doctoral Program of Xi’an Polytechnic University(No.BS202053)the Youth Innovation Team of Shaanxi Universities and Institute of Flexible electronics and Intelligent Textile.
文摘MXene,a transition metal carbide/nitride,has been prominent as an ideal electrochemical active material for supercapacitors.However,the low MXene load limits its practical applications.As environmental concerns and sustainable development become more widely recognized,it is necessary to explore a greener and cleaner technology to recycle textile by-products such as cotton.The present study proposes an effective 3D fabrication method that uses MXene to fabricate waste denim felt into ultralight and flexible supercapacitors through needling and carbonization.The 3D structure provided more sites for loading MXene onto Z-directional fiber bundles,resulting in more efficient ion exchange between the electrolyte and electrodes.Furthermore,the carbonization process removed the specific adverse groups in MXenes,further improving the specific capacitance,energy density,power density and electrical conductivity of supercapacitors.The electrodes achieve a maximum specific capacitance of 1748.5 mF cm-2 and demonstrate remarkable cycling stability maintaining more than 94%after 15,000 galvanostatic charge/discharge cycles.Besides,the obtained supercapacitors present a maximum specific capacitance of 577.5 mF cm^(-2),energy density of 80.2μWh cm^(-2)and power density of 3 mW cm^(-2),respectively.The resulting supercapacitors can be used to develop smart wearable power devices such as smartwatches,laying the foundation for a novel strategy of utilizing waste cotton in a high-quality manner.
文摘In the northern part of the Ordos Basin, there is a 325 km long arc-shaped Langshan uplift and a 15 km-deep Linhe Trench in front of Langshan, which are rare geological phenomena for which origins no one has explained. This article comprehensively analyzes the research achievements over the past 40 years of geology, geomorphology, seismic exploration, paleogeography, and oil and gas exploration in the Ordos Basin and Langshan. It recognizes that the northern part of the Ordos Basin experienced a meteorite impact in the Late Cretaceous period. The impact pushed the block northwest ward, subducting after colliding with igneous rocks in the north. This sudden event formed a clear arc-shaped mountain zone in the north and a wedge-shaped trench in front of the mountain. The chaotic layers, prolonged and continuous faults, and numerous thrust layers in the Langshan, a negative anomaly area in the center of the northern Ordos, abnormal orientation of crystalline basement structures in the north of Ordos, Moho uplift, and distribution of meteorite fragments in the northwest of Langshan, all of these geological phenomena support the occurrence of the meteorite impact event, forming the arc-shaped Langshan and the Trench.
基金the National council for scientific and technological development(CNPq)and Higher Education Personnel Improvement Coordination(CAPES)。
文摘Needle chlorosis(NC)in Pinus taeda L.systems in Brazil becomes more frequent after second and third harvest rotation cycles.In a study to identify factors contributing to yellowing needle chorosis(YNC),trees were grown in soils originating from contrasting parent materials,and soils and needles(whole,green and chlorotic portions)from 1-and 2-year-old branches and the first and second needle flush release at four sites with YNC on P.taeda were analyzed for various elements and properties.All soils had very low base levels(Ca^(2+),Mg^(2+)and K^(+))and P,suggesting a possible lack of multiple elements.YNC symptoms started at needle tips,then extended toward the needle base with time.First flush needles had longer portions with YNC than second flush needles did.Needles from the lower crown also had more symptoms along their length than those higher in the canopy.Symptoms were similar to those reported for Mg.In chlorotic portions,Mg and Ca concentrations were well below critical values;in particular,Mg levels were only one third of the critical value of 0.3 g kg^(-1).Collectively,results suggest that Mg deficiency is the primary reason for NC of P.taeda in various parent soils in Brazil.
基金supported by National Natural Science Foundations of China(Nos.51977023 and 52077026)the Fundamental Research Funds for the Central Universities(No.DUT23YG227)。
文摘In this paper,self-designed multi-hollow needle electrodes are used as a high-voltage electrode in a packed bed dielectric barrier discharge reactor to facilitate fast gas flow through the active discharge area and achieve large-volume stable discharge.The dynamic characteristics of the plasma,the generated active species,and the energy transfer mechanisms in both positive discharge(PD)and negative discharge(ND)are investigated by using fast-exposure intensified charge coupled device(ICCD)images and time-resolved optical emission spectra.The experimental results show that the discharge intensity,number of discharge channels,and discharge volume are obviously enhanced when the multi-needle electrode is replaced by a multihollow needle electrode.During a single voltage pulse period,PD mainly develops in a streamer mode,which results in a stronger discharge current,luminous intensity,and E/N compared with the diffuse mode observed in ND.In PD,as the gap between dielectric beads changes from 0 to250μm,the discharge between the dielectric bead gap changes from a partial discharge to a standing filamentary micro-discharge,which allows the plasma to leave the local area and is conducive to the propagation of surface streamers.In ND,the discharge only appears as a diffusionlike mode between the gap of dielectric beads,regardless of whether there is a discharge gap.Moreover,the generation of excited states N_(2)^(+)(B^(2)∑_(u)^(+))and N2(C^(3)Π_(u))is mainly observed in PD,which is attributed to the higher E/N in PD than that in ND.However,the generation of the OH(A^(2)∑^(+))radical in ND is higher than in PD.It is not directly dominated by E/N,but mainly by the resonant energy transfer process between metastable N_(2)(A^(3)∑_(u)^(+))and OH(X^(2)Π).Furthermore,both PD and ND demonstrate obvious energy relaxation processes of electron-to-vibration and vibration-to-vibration,and no vibration-to-rotation energy relaxation process is observed.
基金financed by the grants from Scientific Research Fund Project of Yunnan Provincial Department of Education(No.2022Y377)Youth Fund for Humanities and Social Sciences Research Project of the Ministry of Education(No.20YJCZH246)National Social Science Fund Project(No.16BXW055)。
文摘In the early 20th century,French vice-consul George Souliéde Morant encountered acupuncture during his visit to China,and then brought it back to France.After more than a century,his collection was transported from Paris,France to Kunming,China,and later recognized as a Chinese national third-class precious cultural heritage.Currently housed in the Museum of Western Studies on Chinese Medicine at Yunnan University of Chinese Medicine,this set of instruments includes one needle holder converted from a fan-shaped holder,ten acupuncture needles,and eleven paper tags handwritten in English with names of diseases and body parts.This article attempts to present the foundational information and historical significance of this collection of this set of late Qing dynasty acupuncture instruments by reviewing the collection and related research on acupuncture instruments,consulting acupuncture professionals,measuring the detailed information of the set of instruments,and employing a method of translating and summarizing the content of the attached tags.
基金performed within the framework of the State assignment of the IHCE SB RAS,project No.FWRM-2021-0014.
文摘The development of a nanosecond discharge in a pin-to-pin gap filled with air at atmospheric pressure has been studied with high temporal and spatial resolutions from a breakdown start to the spark decay.Positive and negative nanosecond voltage pulses with an amplitude of tens of kilovolts were applied.Time-resolved images of the discharge development were taken with a fourchannel Intensified Charge Coupled Device(ICCD)camera.The minimum delay between the camera channels could be as short as≈0.1 ns.This made it possible to study the gap breakdown process with subnanosecond resolution.It was observed that a wide-diameter streamer develops from the high-voltage pointed electrode.The ionization processes near the grounded pin electrode started when the streamer crossed half of the gap.After bridging the gap by the streamer,a diffuse discharge was formed.The development of spark leaders from bright spots on the surface of the pointed electrodes was observed at the next stage.It was found that the rate of development of the spark leader is an order of magnitude lower than that of the wide-diameter streamer.Long thin luminous tracks were observed against the background of a discharge plasma glow.It has been established that the tracks are adjacent to brightly glowing spots on the electrodes and are associated with the flight of small particles.
文摘BACKGROUND The overlap of imaging manifestations among distinct splenic lesions gives rise to a diagnostic dilemma.Consequently,a definitive diagnosis primarily relies on his-tological results.The ultrasound(US)-guided coaxial core needle biopsy(CNB)not only procures sufficient tissue to help clarify the diagnosis,but reduces the incidence of puncture-related complications.CASE SUMMARY A 41-year-old female,with a history of pulmonary tuberculosis,was admitted to our hospital with multiple indeterminate splenic lesions.Gray-scale ultrasono-graphy demonstrated splenomegaly with numerous well-defined hypoechoic ma-sses.Abdominal contrast-enhanced computed tomography(CT)showed an en-larged spleen with multiple irregular-shaped,peripherally enhancing,hypodense lesions.Positron emission CT revealed numerous abnormal hyperglycemia foci.These imaging findings strongly indicated the possibility of infectious disease as the primary concern,with neoplastic lesions requiring exclusion.To obtain the precise pathological diagnosis,the US-guided coaxial CNB of the spleen was ca-rried out.The patient did not express any discomfort during the procedure.CONCLUSION Percutaneous US-guided coaxial CNB is an excellent and safe option for obtaining precise splenic tissue samples,as it significantly enhances sample yield for exact pathological analysis with minimum trauma to the spleen parenchyma and sur-rounding tissue.
文摘BACKGROUND Acute injuries to the tibiofibular syndesmosis,often associated with high ankle sprains or malleolar fractures,require precise diagnosis and treatment to prevent long-term complications.This case report explores the use of needle arthroscopy as a minimally invasive technique for the repair of tibiofibular syndesmosis injuries.CASE SUMMARY We report on a 40-year-old male patient who presented with a trimalleolar fracture and ankle subluxation following a high ankle sprain.Due to significant swelling and poor soft tissue quality,initial management involved external stabilization.Subsequently,needle arthroscopy was employed to assess and treat the tibiofibular syndesmosis injury.The procedure,performed under spinal anesthesia and fluoroscopic control,included nanoscopic evaluation of the ankle joint and reduction of the syndesmosis using a suture button.Follow-up assessments showed significant improvement in pain levels,range of motion,and functional scores.At 26 weeks post-procedure,the patient achieved full range of motion and pain-free status.Needle arthroscopy offers a promising alternative for the management of acute tibiofibular syndesmosis injuries,combining diagnostic and therapeutic capabilities with minimal invasiveness.CONCLUSION This technique may enhance clinical outcomes and reduce recovery times,warranting further investigation and integration into clinical practice.
文摘Background: As the population age structure gradually ages, more and more elderly people were found to have pulmonary nodules during physical examinations. Most elderly people had underlying diseases such as heart, lung, brain and blood vessels and cannot tolerate surgery. Computed tomography (CT)-guided percutaneous core needle biopsy (CNB) was the first choice for pathological diagnosis and subsequent targeted drugs, immune drugs or ablation treatment. CT-guided percutaneous CNB requires clinicians with rich CNB experience to ensure high CNB accuracy, but it was easy to cause complications such as pneumothorax and hemorrhage. Three-dimensional (3D) printing coplanar template (PCT) combined with CT-guided percutaneous pulmonary CNB biopsy has been used in clinical practice, but there was no prospective, randomized controlled study. Methods: Elderly patients with lung nodules admitted to the Department of Oncology of our hospital from January 2019 to January 2023 were selected. A total of 225 elderly patients were screened, and 30 patients were included after screening. They were randomly divided into experimental group (Group A: 30 cases) and control group (Group B: 30 cases). Group A was given 3D-PCT combined with CT-guided percutaneous pulmonary CNB biopsy, Group B underwent CT-guided percutaneous pulmonary CNB. The primary outcome measure of this study was the accuracy of diagnostic CNB, and the secondary outcome measures were CNB time, number of CNB needles, number of pathological tissues and complications. Results: The diagnostic accuracy of group A and group B was 96.67% and 76.67%, respectively (P = 0.026). There were statistical differences between group A and group B in average CNB time (P = 0.001), number of CNB (1 vs more than 1, P = 0.029), and pathological tissue obtained by CNB (3 vs 1, P = 0.040). There was no statistical difference in the incidence of pneumothorax and hemorrhage between the two groups (P > 0.05). Conclusions: 3D-PCT combined with CT-guided percutaneous CNB can improve the puncture accuracy of elderly patients, shorten the puncture time, reduce the number of punctures, and increase the amount of puncture pathological tissue, without increasing pneumothorax and hemorrhage complications. We look forward to verifying this in a phase III randomized controlled clinical study. .
文摘Introduction: The frequent late-stage diagnosis of chronic kidney disease (CKD) constrains the treatment choices for nephrologists. Renal biopsy (RB) is crucial for accurately identifying renal lesions. This key nephrological procedure, however, is invasive and not without potential complications. The purpose of this study was to evaluate the indications, frequency, and histological lesion profiles of renal biopsies in Togo. Materials and Methods: We conducted a descriptive cross-sectional study encompassing all renal biopsies performed in Togo from the inception of nephrology services to the present. Data were compiled from the medical records of the patients. Results: From 2015 to 2023, 68 high-quality renal biopsies were executed in Togo. The patients had an average age of 30.6 years, with a predominance of males (69.1%). The most common indication was nephrotic syndrome, accounting for 66.2% of cases. Histologically, glomerulopathies were predominant, representing 61.8% of lesions, followed by vascular nephropathies (25%) and tubulointerstitial nephropathies (13.2%). The most frequently observed primary glomerulopathy was focal segmental glomerulosclerosis (FSGS). Gross hematuria was the sole complication, occurring in 1.4% of the cases. Conclusion: RB is an evolving practice in Togo. Glomerulopathies are the most commonly observed lesions. The histological categorization of renal lesions is vital for clinicians in their diagnostic reasoning and approach.
基金Supported by Guangxi Natural Science Foundation(2018GXNSFAA050141)Basic AbilityImprovement Project for Young and Middle-aged Teachers in Guangxi Zhuang Autonomous Region(2019KY0336)Guangxi Famous Tradi-tional Chinese Medicine Inheritance Studio-Qin Zujie[GuiZhongYiYaoKeJiao-Fa(2021)No.6].
文摘[Objectives]To observe the clinical effect of the lotus needle cupping therapy for removing blood stasis in Zhuang medicine in treating PHNand its influence on inflammatory factors.[Methods]96 patients with PHN were randomly divided into three groups:lotus nee-dle cupping therapy group,TCM surrounding acupuncture group and gabapentin group.Venous blood and acupoint blood were collected at 0,21 and 42 d of treatment,and the expression levels of 5-HT,SP and CGRPinflammatory mediators were detected before and after treatment.The changes of VAS scores before,during and after treatment and the clinical efficacy were observed.[Results]The total effective rate of the lotus needle cupping group was 87.50%,which was better than that of the TCM acupuncture group(81.25%)and the gabapentin group(62.50%);after treatment,the VAS scores and the expression of inflammatory mediators in the three groups of patients were lower than those before treatment,and the decrease was more significant in the treatment group(P<0.05).[Conclusions]The lotus needle cupping therapy for removing blood stasis in Zhuang medicine is effective in treating PHN,and its mechanism is to reduce the release of inflammatory media-tors,reduce hyperalgesia,relieve pain and improve the quality of life of patients.
文摘MANCHESTER,UK-Having successfully demonstrated its WebSpector automated fabric inspection system detecting faults on camouflage fabrics at speeds of up to 100metres a minute during ITMA 2023,BTMA member Shelton Vision has secured an unprecedented number of new orders in many fields of the textile industry.The company has subsequently been recruiting additional staff in order to beef up its operations to meet delivery times and to grow capacity for the ongoing increased demand.
文摘Dear Editor,Submacular hemorrhage(SMH)is the accumulation of blood in the macular region caused by changes in retinal or choroidal circulation[1].SMH may be caused by age-related macular degeneration(AMD),pathological myopia,polypoid choroidal angiopathy(PCV)or retinal macroaneurysm[2].
基金The Executive Agency for Higher Education,Research,Development and Innovation Funding-research,No.PN-Ⅲ-P1-1.2-PCCDI-2017-0797 (PANCNGS)
文摘BACKGROUND Genetic tests are increasingly performed for the management of unresectable pancreatic cancer.For genotyping aimed samples current guidelines recommend using core specimens,although based on moderate quality evidence.However,in clinical practice among the endoscopic ultrasound(EUS) guided tissue acquisition methods,fine needle aspiration(FNA) is the most widely performed.AIM To assess the adequacy for next generation sequencing(NGS) of the DNA yielded from EUS-FNA pancreatic adenocarcinoma(PDAC) samples.METHODS Between November 2018 and December 2021,105 patients with PDAC confirmed by EUS-FNA were included in the study at our tertiary gastroenterology center.Either 22 gauge(G) or 19G FNA needles were used.One pass was dedicated to DNA extraction.DNA concentration and purity(A260/280,A260/230) were assessed by spectrophotometry.We assessed the differences in DNA parameters according to needle size and tumor characteristics(size,location) and the adequacy of the extracted DNA for NGS(defined as A260/280 ≥ 1.7,and DNA yield:≥ 10 ng for amplicon based NGS,≥ 50 ng for whole exome sequencing [WES],≥ 100 ng for whole genome sequencing [WGS]) by analysis of variance and ttest respectively.Moreover,we compared DNA purity parameters across the different DNA yield categories.RESULTS Our cohort included 49% male patients,aged 67.02 ± 8.38 years.The 22G needle was used in 71%of the cases.The DNA parameters across our samples varied as follows:DNA yield:1289 ng(inter quartile range:534.75-3101),A260/280 = 1.85(1.79-1.86),A260/230 = 2.2(1.72-2.36).DNA yield was > 10 ng in all samples and > 100 ng in 93% of them(one sample < 50 ng).There were no significant differences in the concentration and A260/280 between samples by needle size.Needle size was the only independent predictor of A260/230 which was higher in the 22G samples(P =0.038).NGS adequacy rate was 90% for 19G samples regardless of NGS type,and for 22G samples it reached 89% for WGS adequacy and 91% for WES and amplicon based NGS.Samples with DNA yield > 100 ng had significantly higher A260/280(1.89 ± 0.32 vs 1.34 ± 0.42,P = 0.013).Tumor characteristics were not corelated with the DNA parameters.CONCLUSION EUS-FNA PDAC samples yield DNA adequate for subsequent NGS.DNA amount was similar between 22G and 19G FNA needles.DNA purity parameters may vary indirectly with needle size.
基金The grant“Biopolymer substrates for the determination of opioids in biofluids by ambient mass spectrometry”(Grant No.:PID2020-112862RB-I00)funded by MCIN/AEI/10.13039/501100011033(Feder“Una manera de hacer Europa”)is gratefully acknowledged。
文摘This study proposes a hypodermic needle(HN)as a sorbent holder and an electrospray(ESI)emitter,thus combining extraction and analysis in a single device.A novel nylon 6-cellulose(N6-Cel)composite sorbent is proposed to extract methadone from oral fluid samples.The cellulosic substrate provides the composite with high porosity,permitting the flow-through of the sample,while the polyamide contributes to the extraction of the analyte.The low price of the devices(considering the holder and the sorbent)contributes to the affordability of the method,and their small size allows easy transportation,opening the door to on-site extractions.Under the optimum conditions,the analyte can be determined by high-resolution ambient ionization mass spectrometry at a limit of detection(LOD)as low as 0.3 mg/L and precision(expressed as relative standard deviation,RSD)better than 9.3%.The trueness,expressed as relative recovery(RR),ranged from 90%to 109%.As high-resolution mass spectrometers are not available in many laboratories,the method was also adapted to low-resolution spectrometers.In this sense,the direct infusion of the eluates in a triple quadrupole-mass spectrometry provided an LOD of 2.2 mg/L.The RSD was better than 5.3%,and the RR ranged from 96%to 121%.
文摘The relationship between the microstructure and the practical performance of two different copper-beryllium alloys including their lifetime has been investigated.Herein,two valves made of two different alloys with very similar compositions and the same heat treatment methods were investigated by various standard techniques including metallography,X-ray diffraction,chemical composition,microhardness,and thermal conductivity measurements.Although both alloys experienced the same heat-treatment processes,they revealed different thermal and mechanical properties due to the minor difference in their chemical composition.The alloy providing a longer lifetime (40%more) as the tip had a higher thermal conductivity of 280.3 W(m·K)^(-1) (about two times that of the other alloy).Regarding the metallography images and the measured thermal conductivity values of the alloys,the extended lifetime of the nozzle with the optimum performance is ascribed to its biphasic microstructure and the minor grain boundaries and interfacial thermal resistance.And important difference in the chemical composition was investigated in this study.
基金supported by National Natural Science Foundation of China (Nos.52207158 and 51821005)the Fundamental Research Funds for the Central Universities (HUST: No.2022JYCXJJ012)the National Key Research and Development Program of China (Nos.2016YFC0401002 and 2016YFC0401006)。
文摘Corona discharge, as a common means to obtain non-equilibrium plasma, can generally obtain high-concentration plasma by increasing discharge points to meet production needs. However,the existing numerical simulation models used to study multi-point corona discharge are all calculations of small-scale space models, which cannot obtain the distribution characteristics of plasma in large space. Based on our previous research, this paper proposes a hybrid model for studying the distribution of multi-point discharge plasma in large-scale spaces, which divides the computational domain and computes separately with the hydrodynamic model and the ion mobility model. The simulation results are verified by a needle–ball electrode device. Firstly, the electric field distribution and plasma distribution of the needle electrodes with single tip and double tips are compared and discussed. Secondly, the plasma distribution of the needle electrode with the double tip at different voltages is investigated. Both computational and experimental results indicate that the charged particle concentration and current of the needle electrode with double tips are both twice as high as those of the needle electrode with a single tip. This model can extend the computational area of the multi-point corona discharge finite element model to the sub-meter(25 cm) or meter level, which provides an effective means to study the plasma distribution generated by multiple discharge points in large-scale space.
