The circular electron-positron collider(CEPC)is designed to precisely measure the properties of the Higgs boson,study electroweak interactions at the Z-boson peak,and search for new physics beyond the Standard Model.A...The circular electron-positron collider(CEPC)is designed to precisely measure the properties of the Higgs boson,study electroweak interactions at the Z-boson peak,and search for new physics beyond the Standard Model.As a component of the 4th conceptual CEPC detector,the drift chamber facilitates the measurement of charged particles.This study implemented a Geant4-based simulation and track reconstruction for the drift chamber.For the simulation,detector construction and response were implemented and added to the CEPC simulation chain.The development of track reconstruction involves track finding using the combinatorial Kalman filter method and track fitting using the tool of GenFit.Using the simulated data,the tracking performance was studied.The results showed that both the reconstruction resolution and tracking efficiency satisfied the requirements of the CEPC experiment.展开更多
Active target time projection chambers are state-of-the-art tools in the field of low-energy nuclear physics and are particularly suitable for experiments using low-intensity radioactive ion beams or gamma rays.The Fu...Active target time projection chambers are state-of-the-art tools in the field of low-energy nuclear physics and are particularly suitable for experiments using low-intensity radioactive ion beams or gamma rays.The Fudan multi-purpose active target time projection chamber(fMeta-TPC)with 2048 channels was developed to studyα-clustering nuclei.This study focused on the photonuclear reaction with a laser Compton scattering gamma source,particularly for the decay of the highly excitedαcluster state.The design of fMeta-TPC is described in this paper.A comprehensive evaluation of its offline performance was conducted using an ultraviolet laser and ^(241)Amαsource.The results showed that the intrinsic angular resolution of the detector was within 0.30°,and the detector had an energy resolution of 6.85%for 3.0 MeVαparticles.The gain uniformity of the detector was approximately 10%(RMS/Mean),as tested by the ^(55)Fe X-ray source.展开更多
Enhancing plasma uniformity can be achieved by modifying coil and chamber structures in radio frequency inductively coupled plasma(ICP)to meet the demand for large-area and uniformly distributed plasma in industrial m...Enhancing plasma uniformity can be achieved by modifying coil and chamber structures in radio frequency inductively coupled plasma(ICP)to meet the demand for large-area and uniformly distributed plasma in industrial manufacturing.This study utilized a two-dimensional self-consistent fluid model to investigate how different coil configurations and chamber aspect ratios affect the radial uniformity of plasma in radio frequency ICP.The findings indicate that optimizing the radial spacing of the coil enhances plasma uniformity but with a reduction in electron density.Furthermore,optimizing the coil within the ICP reactor,using the interior point method in the Interior Point Optimizer significantly enhances plasma uniformity,elevating it from 56%to 96%within the range of the model sizes.Additionally,when the chamber aspect ratio k changes from 2.8 to 4.7,the plasma distribution changes from a center-high to a saddleshaped distribution.Moreover,the plasma uniformity becomes worse.Finally,adjusting process parameters,such as increasing source power and gas pressure,can enhance plasma uniformity.These findings contribute to optimizing the etching process by improving plasma radial uniformity.展开更多
A dedicated weak current measurement system was designed to measure the weak currents generated by the neutron ionization chamber.This system incorporates a second-order low-pass filter circuit and the Kalman filterin...A dedicated weak current measurement system was designed to measure the weak currents generated by the neutron ionization chamber.This system incorporates a second-order low-pass filter circuit and the Kalman filtering algorithm to effectively filter out noise and minimize interference in the measurement results.Testing conducted under normal temperature conditions has demonstrated the system's high precision performance.However,it was observed that temperature variations can affect the measurement performance.Data were collected across temperatures ranging from -20 to 70℃,and a temperature correction model was established through linear regression fitting to address this issue.The feasibility of the temperature correction model was confirmed at temperatures of -5 and 40℃,where relative errors remained below 0.1% after applying the temperature correction.The research indicates that the designed measurement system exhibits excellent temperature adaptability and high precision,making it particularly suitable for measuring weak currents.展开更多
Cancer is a major societal public health and economic problem, responsible for one in every six deaths. Radiotherapy is the main technique of treatment for more than half of cancer patients. To achieve a successful ou...Cancer is a major societal public health and economic problem, responsible for one in every six deaths. Radiotherapy is the main technique of treatment for more than half of cancer patients. To achieve a successful outcome, the radiation dose must be delivered accurately and precisely to the tumor, within ± 5% accuracy. Smaller uncertainties are required for better treatment outcome. The objective of the study is to investigate the uncertainty of measurement of external radiotherapy beam using a standard ionization chamber under reference conditions. Clinical farmers type ionization chamber measurement was compared against the National Reference standard, by exposing it in a beam 60Co gamma source. The measurement set up was carried out according to IAEA TRS 498 protocol and uncertainty of measurement evaluated according to GUM TEDDOC-1585. Evaluation and analysis were done for the identified subjects of uncertainty contributors. The expanded uncertainty associated with 56 mGy/nC ND,W was found to be 0.9% corresponding to a confidence level of approximately 95% with a coverage factor of k = 2. The study established the impact of dosimetry uncertainty of measurement in estimating external radiotherapy dose. The investigation established that the largest contributor of uncertainty is the stability of the ionization chamber at 36%, followed by temperature at 22% and positioning of the chamber in the beam at 8%. The effect of pressure, electrometer, resolution, and reproducibility were found to be minimal to the overall uncertainty. The study indicate that there is no flawless measurement, as there are many prospective sources of variation. Measurement results have component of unreliability and should be regarded as best estimates of the true value. .展开更多
Objective:To explore the corrective effect of posterior chamber intraocular lens implantation with phakic eyes in the treatment of high myopia and astigmatism.Methods:From May 2023,the hospital began to collect the ca...Objective:To explore the corrective effect of posterior chamber intraocular lens implantation with phakic eyes in the treatment of high myopia and astigmatism.Methods:From May 2023,the hospital began to collect the case data of diagnosis and treatment of high myopia and astigmatism.By May 2024,310 cases were included,all of which were treated with posterior chamber intraocular lens implantation.The visual acuity,astigmatism and axial position of the intraocular lens were observed before and after treatment.Results:At different time points after the operation,the patient’s vision was significantly improved compared with that before the operation(P<0.05),and the vision level was equal to or greater than the best-corrected vision before the operation.At different time points after the operation,the average rotation of the intraocular lens was less than 5 degrees.Astigmatism was significantly lower than that before the operation(P<0.05).After the operation,the intraocular pressure increased in 11 cases,accounting for 3.55%,with no adverse complications such as lens turbidity,glare and obvious halo occurring.Conclusion:The posterior chamber intraocular lens implantation with phakic eyes has an ideal correction effect in the treatment of high myopia and astigmatism,which can effectively improve the vision level of patients and reduce the degree of astigmatism,and has high effectiveness and safety.展开更多
The impacts of different 03 concentration on the biomass and yield of rice were studied by using OTC-1 open-top chambers. Experimental treatments included the activated charcoal-filtered air. (CFA), 50 nl/L (CF50), 10...The impacts of different 03 concentration on the biomass and yield of rice were studied by using OTC-1 open-top chambers. Experimental treatments included the activated charcoal-filtered air. (CFA), 50 nl/L (CF50), 100 nl/L ( CF100) and 200 nl/L (CF200) concentrations of O-3. The O-3 treatments significantly decreased the total biomass per plant. The. elevated O-3 exposure resulted in a more decrease in the root growth than in the shoot growth. Assessments of yield characteristics at the final harvest revealed an O-3-induced decrease in the number of grains per plant, resulting from fewer ears per plant, fewer grains per ear and more unfilled grains per ear. The 1000 grain dry weight and the harvest index (HI) were not changed significantly under 50 nl/L or 100 nl/L O-3 exposure, but reduced by 17.0% and 4.8% by 200nl/L O-3 treatment, respectively. Compared to the CFA treatment, CF50, CF100 and CF200 treatments caused a 8.2%, 26.1%, 49.1% decrease of the grain yield per plant, and a 14.2%, 31.7%, 51.7% decrease of the total biomass per plant, respectively. Linear regression showed that the 7h - daily mean O-3 concentration exposure for 3 months ( July-September) and AOT40 ( cunulative exposure accumulation over threshold 40 nl/L) were well correlated with the relative grain yield. A yield loss of 10% was estimated to be at 46.9 nl/L O-3 for 7h-daily mean O-3 concentration exposure or at 12930nl/(L(.)h) O-3 for AOT40.展开更多
In this article,novel emulation strategies for the sectored multiple probe anechoic chamber(SMPAC)are proposed to enable the reliable evaluation of the massive multiple-input multiple-output(MIMO)device operating at b...In this article,novel emulation strategies for the sectored multiple probe anechoic chamber(SMPAC)are proposed to enable the reliable evaluation of the massive multiple-input multiple-output(MIMO)device operating at beamforming mode,which requires a realistic non-stationary channel environment.For the dynamic propagation emulation,an efficient closed-form probe weighting strategy minimizing the power angular spectrum(PAS)emulation errors is derived,substantially reducing the associated computational complexity.On the other hand,a novel probe selection algorithm is proposed to reproduce a more accurate fading environment.Various standard channel models and setup configurations are comprehensively simulated to validate the capacity of the proposed methods.The simulation results show that more competent active probes are selected with the proposed method compared to the conventional algorithms.Furthermore,the derived closedform probe weighting strategy offers identical accuracy to that obtained with complicated numerical optimization.Moreover,a realistic dynamic channel measured in an indoor environment is reconstructed with the developed methodologies,and 95.6%PAS similarity can be achieved with 6 active probes.The satisfactory results demonstrate that the proposed algorithms are suitable for arbitrary channel emulation.展开更多
AIM:To determine the normative distribution of axial length(AL),anterior chamber depth(ACD),anterior chamber volume(ACV),anterior chamber angle(ACA),and some of their associated factors in subjects aged 60 and over.ME...AIM:To determine the normative distribution of axial length(AL),anterior chamber depth(ACD),anterior chamber volume(ACV),anterior chamber angle(ACA),and some of their associated factors in subjects aged 60 and over.METHODS:In this cross-sectional study,160 clusters were sampled using multi-stage cluster sampling in Tehran,Iran.After a preliminary interview,the participants underwent optometric examinations including visual acuity and refraction measurement followed by slit lamp biomicroscopy.Finally,ocular imaging was done using the Pentacam AXL to measure AL,ACD,ACV,and ACA.RESULTS:A total of 4519 eyes of 2436 participants were evaluated,of whom 58.0%(n=1412)were female.The mean age of the subjects was 67.32±6.05y(range:60-95y).The mean AL,ACD,ACV,and ACA was 23.22 mm(23.18-23.27 mm),2.61 mm(2.59-2.62 mm),126.56 mm3(125.08-128.04 mm3),and 30.61°(30.3°-30.92°),respectively.In the multivariable model,after adjusting for the effect of both eyes,the longest and shortest AL was seen in myopic and hyperopic subjects,respectively.AL,ACD,ACV and ACA were significantly larger in men compared to women(P<0.001).Except ACA,other evaluated parameters showed an inverse correlation with age(P<0.001),however,this correlation was insignificant for AL(P=0.623).CONCLUSION:Normative value of AL,and other biometric parameters are specific for each ethnicity,age and sex group.Any alteration in these parameters and their effect on refraction should be considered in this age group,especially in case of cataract surgery.展开更多
AIM:To describe the outcome of using low-dose laser cycloplasty(LCP)in chronic angle-closure glaucoma(CACG).METHODS:A retrospective case series.Medical charts of CACG patients who underwent LCP in the Eye Hospital of ...AIM:To describe the outcome of using low-dose laser cycloplasty(LCP)in chronic angle-closure glaucoma(CACG).METHODS:A retrospective case series.Medical charts of CACG patients who underwent LCP in the Eye Hospital of Wenzhou Medical University were reviewed.The main outcomes included intraocular pressure(IOP),the number of glaucoma medication,anterior segment parameters and surgery-related complications.RESULTS:A total of 7 eyes of 7 CACG patients(age 38.9±11.0y)underwent LCP with a mean follow-up of 27.1±13.7mo(range 16-48mo).Following LCP,mean IOP and glaucoma medications decreased from 26.1±6.1 mm Hg with 3.1±1.1 glaucoma medications pre-treatment to 14.9±3.1 mm Hg(P=0.027)with 0.4±1.1 glaucoma medications(P=0.001)at final follow-up.The anterior chamber depth(ACD),angle opening distance500 and trabecular-iris angle increased from 1.65±0.33 mm,0.05 mm(range 0-0.30 mm)and 5.1°(range,0-31.97°)at baseline to 1.98±0.43 mm(P=0.073),0.53 mm(range 0.42-0.91 mm,P=0.015),45.9°(range,40.2°-59.4°),(P=0.015)in the long-term follow-up,respectively.The deepening of ACD and reopening of anterior chamber angle(ACA)was observed in 6 eyes(85.7%).CONCLUSION:LCP is a promising treatment option for patients with CACG via reducing IOP and glaucoma medication without serious complications.In addition,LCP can bring a significant deepening in ACD and reopening of ACA.展开更多
Hydrogen peroxide synthesis by electro-reduction of O_(2) to substitute the current anthraquinone process has attracted a great deal of attention. Low oxygen utilization rate and low hydrogen peroxide production remai...Hydrogen peroxide synthesis by electro-reduction of O_(2) to substitute the current anthraquinone process has attracted a great deal of attention. Low oxygen utilization rate and low hydrogen peroxide production remain obstacles to electro-Fenton application. In situ H_(2)O_(2) generated by electrochemical reaction depends on the electrochemical performance of the cathode and the structure of the reactor. Here, novel graphite felt(GF) modified by La-doped CeO_(2)(La-CeO_(2)) was developed as a cathode. A new double chamber electro-Fenton reactor was proposed, where an organic ultrafiltration membrane was used to prevent H_(2)O_(2) from spreading to the anode. The effects of hydrothermal temperature, time and urea concentration on the electrochemical properties of graphite felt were investigated. The accumulated concentration of H_(2)O_(2) on the modified cathode reached 218.4 mg·L^(-1)in 1 h when the optimal conditions of hydrothermal temperature 120 ℃ and urea concentration 0.55%(mass) in 24 h. The degradation rate of methyl orange reached 98.29%. The new electro-Fenton reactor can efficiently produce hydrogen peroxide to degrade various organic substances and has a high potential for treating wastewater in the chemical industry.展开更多
AIM:To evaluate the postoperative refractive prediction error(PE)and determine the factors that af fect the refractive outcomes of combined pars plana vitrectomy(PPV)or silicone oil removal(SOR)with cataract surgery.M...AIM:To evaluate the postoperative refractive prediction error(PE)and determine the factors that af fect the refractive outcomes of combined pars plana vitrectomy(PPV)or silicone oil removal(SOR)with cataract surgery.METHODS:The study is a retrospective,case-series study.Totally 301 eyes of 301 patients undergoing combined PPV/SOR with cataract surgery were enrolled.Eligible individuals were separated into four groups according to their preoperative diagnoses:silicone oil-filled eyes after PPV(group 1),epiretinal membrane(group 2),macular hole(group 3),and primary retinal detachment(RD;group 4).The variables af fecting postoperative refractive outcomes were analyzed,including age,gender,preoperative best-corrected visual acuity(BCVA),axial length(AL),keratometry average,anterior chamber depth(ACD),intraocular tamponade,and vitreoretinal pathology.The outcome measurements include the mean refractive PE and the proportions of eyes with a PE within±0.50 diopter(D)and±1.00 D.RESULTS:For all patients,the mean PE was-0.04±1.17 D,and 50.17%of patients(eyes)had a PE within±0.50 D.There was a significant difference in refractive outcomes among the four groups(P=0.028),with RD(group 4)showing the least favorable refractive outcome.In multivariate regression analysis,only AL,vitreoretinal pathology,and ACD were strongly associated with PE(all P<0.01).Univariate analysis revealed that longer eyes(AL>26 mm)and a deeper ACD were correlated with hyperopic PE,and shorter eyes(AL<26 mm)and a shallower ACD were correlated with myopic PE.CONCLUSION:RD patients have the least favorable refractive outcome.AL,vitreoretinal pathology,and ACD are strongly associated with PE in the combined surgery.These three factors affect refractive outcomes and thus can be used to predict a better postoperative refractive outcome in clinical practice.展开更多
The results of analysis of technical possibilities to increase engine efficiency were presented in this article. This problem was connected with kinematics properties of air inflow to the combustion chamber. The possi...The results of analysis of technical possibilities to increase engine efficiency were presented in this article. This problem was connected with kinematics properties of air inflow to the combustion chamber. The possibilities of intake airflow modulation have a positive impact on combustion process, level of engine usable parameters and emission. This issue was presented on the results of experimental research. Results of baseline research gave information about the flow resistance. On the basis of results of experimental research, conclusions were formulated.展开更多
Contaminated or infected patients present a risk of cross-contamination for emergency responders, attending medical personnel and medical facilities as they enter a treatment facility. The controlled conditions of an ...Contaminated or infected patients present a risk of cross-contamination for emergency responders, attending medical personnel and medical facilities as they enter a treatment facility. The controlled conditions of an aerosol test chamber are required to examine factors of contamination, decontamination, and cross-contamination. This study presents the design, construction, and a method for characterizing an aerosol test chamber for a full-sized manikin on a standard North Atlantic Treaty Organization litter. The methodology combined air velocity measurements, aerosol particle counts and size distributions, and computational fluid dynamics modeling to describe the chamber’s performance in three dimensions. This detailed characterization facilitates future experimental design by predicting chamber performance for a variety of patient-focused research.展开更多
Radon is the most important source of natural radiation to human beings and the second major causative agent of lung cancer other than smoking. In recent years, the hazards of human exposure to thoron (Rn-220), anothe...Radon is the most important source of natural radiation to human beings and the second major causative agent of lung cancer other than smoking. In recent years, the hazards of human exposure to thoron (Rn-220), another isotope of radon, and its progeny have gained consensus. To accurately evaluate the dose level and hazards of Rn-220 and its progeny, a standard Rn-220 chamber with strong regulation ability for Rn-220 and its progeny needs to be established for the scale or calibration of measurement instruments. This paper describes the hazards, sources, behavioral characteristics of Rn-220 and its progeny, and some representative Rn-220 chambers established in various countries.展开更多
Background: The burden of cataract and glaucoma has been increasing. Primary angle closure occurs as a result of crowded anterior segment anatomy causing appositional contact between peripheral iris and trabecular mes...Background: The burden of cataract and glaucoma has been increasing. Primary angle closure occurs as a result of crowded anterior segment anatomy causing appositional contact between peripheral iris and trabecular meshwork. Lens extraction has been proposed as a method of deepening anterior chamber and managing intraocular pressure. Purpose: To assess changes in anterior chamber depth after phacoemulsification with intraocular lens implantation in narrow angle eyes. Design: Prospective controlled trial (before-after) study. Method: The study was conducted from March 2015 to August 2017 among the patients of department of Ophthalmology of BSMMU who were diagnosed as cataract with narrow angles. Anterior chamber angle grading of 2 or less (Shaffer grading) in 3 or more quadrants was considered narrow angle (NA). The purposive type sampling technique was applied to collect sample from the study population, as per inclusion and exclusion criteria. Complete clinical evaluation including history, physical examination, relevant ocular examinations and systemic examinations were performed. In this prospective study, subjects underwent phacoemulsification with foldable lens implantation. A scan ultrasonography was performed preoperatively and 10<sup>th</sup> and 30<sup>th</sup> postoperative days of surgery. Results: Thirty eyes of 29 patients included in the study, male: female ratio was 1:1, with an overall mean age of 62.03 ± 8.95 years. The mean preoperative central ACD was 2.95 ± 0.35 mm. At 10<sup>th</sup> and 30<sup>th</sup> POD mean central ACD were 3.94 ± 0.32, and 3.92 ± 0.28 mm respectively. Mean of increase in central ACD at final follow-up was 0.96 mm (p Conclusion: Phacoemulsification with posterior chamber in bag lens implantation can deepen the anterior chamber depth in patients with narrow angles. Based on these findings, it is concluded that phacoemulsification with foldable intraocular lens implantation is an effective tool in deepening the anterior chamber.展开更多
The plenum chamber of a heat setting machine is a key structure for distributing hot air to different air channels.Its outlet velocity uniformity directly determines the heating uniformity of textiles,significantly af...The plenum chamber of a heat setting machine is a key structure for distributing hot air to different air channels.Its outlet velocity uniformity directly determines the heating uniformity of textiles,significantly affecting the heat setting performance.In a traditional heat setting machine,the outlet airflow maldistribution of the plenum chamber still exists.In this study,a novel plenum chamber with an airfoil baffle was established to improve the uniformity of the velocity distribution at the outlet in a heat setting machine.The structural influence of the plenum chamber on the velocity distribution was investigated using a computational fluid dynamics program.It was found that a chamber with a smaller outlet partition thickness had a better outlet velocity uniformity.The structural optimization of the plenum chamber was conducted using the particle swarm optimization algorithm.The outlet partition thickness,the transverse distance and the longitudinal distance of the optimized plenum chamber were 20,686.2 and 274.6 mm,respectively.Experiments were carried out.The experimental and simulated results showed that the optimized plenum chamber with an airfoil baffle could improve the outlet velocity uniformity.The air outlet velocity uniformity index of the optimized plenum chamber with an airfoil baffle was 4.75%higher than that of the plenum chamber without an airfoil baffle and 5.98%higher than that of the conventional chamber with a square baffle in a commercial heat setting machine.展开更多
Radon(Rn)is a naturally occurring radioactive inert gas in nature,and^(222)Rn has been routinely used as a powerful tracer in various aquatic environmental research on timescales of hours to days,such as submarine gro...Radon(Rn)is a naturally occurring radioactive inert gas in nature,and^(222)Rn has been routinely used as a powerful tracer in various aquatic environmental research on timescales of hours to days,such as submarine groundwater discharge.Here we developed a new approach to measure^(222)Rn in discrete water samples with a wide range of^(222)Rn concentrations using a Pulsed Ionization Chamber(PIC)Radon Detector.The sensitivity of the new PIC system is evaluated at 6.06 counts per minute for 1 Bq/L when a 500 mL water sample volume is used.A robust logarithmic correlation between sample volumes,ranging from 250 mL to 5000 mL,and system sensitivity obtained in this study strongly suggests that this approach is suitable for measuring radon concentration levels in various natural waters.Compared to the currently available methods for measuring radon in grab samples,the PIC system is cheaper,easier to operate and does not require extra accessories(e.g.,drying tubes etc.)to maintain stable measurements throughout the counting procedure.展开更多
Passive-warming, open-top chambers(OTCs) are widely applied for studying the effects of future climate warming on coastal wetlands. In this study, a set of six OTCs were established at a Phragmites wetland located in ...Passive-warming, open-top chambers(OTCs) are widely applied for studying the effects of future climate warming on coastal wetlands. In this study, a set of six OTCs were established at a Phragmites wetland located in the Yellow River Delta of Dongying City, China. With data collected through online transmission and in-situ sensors, the attributes and patterns of realized OTCs warming are demonstrated.The authors also quantified the preliminary influence of experimental chamber warming on plant traits.OTCs produced an elevated average air temperature of 0.8°C(relative to controls) during the growing season(June to October) of 2018, and soil temperatures actually decreased by 0.54°C at a depth of 5 cm and 0.46°C at a depth of 30 cm in the OTCs. Variations in diel patterns of warming depend greatly on the heat sources of incoming radiation in the daytime versus soil heat flux at night. Warming effects were often larger during instantaneous analyses and influenced OTCs air temperatures from-2.5°C to 8.3°C dependent on various meteorological conditions at any given time, ranging from cooling influences from vertical heat exchange and vegetation to radiation-associated warming. Night-time temperature depressions in the OTCs were due to the low turbulence inside OTCs and changes in surface soilatmosphere heat transfer. Plant shoot density, basal diameter, and biomass of Phragmites decreased by23.2%, 6.3%, and 34.0%, respectively, under experimental warming versus controls, and plant height increased by 4.3%, reflecting less carbon allocation to stem structures as plants in the OTCs experienced simultaneous wind buffering. While these passive-warming OTCs created the desired warming effects both to the atmosphere and soils, pest damages on the plant leaves and lodging within the OTCs were extensive and serious, creating the need to consider control options for these chambers and the replicated OTCs studies underway in other Chinese Phragmites marshes(Panjin and Yancheng).展开更多
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.12025502 and 12341504)。
文摘The circular electron-positron collider(CEPC)is designed to precisely measure the properties of the Higgs boson,study electroweak interactions at the Z-boson peak,and search for new physics beyond the Standard Model.As a component of the 4th conceptual CEPC detector,the drift chamber facilitates the measurement of charged particles.This study implemented a Geant4-based simulation and track reconstruction for the drift chamber.For the simulation,detector construction and response were implemented and added to the CEPC simulation chain.The development of track reconstruction involves track finding using the combinatorial Kalman filter method and track fitting using the tool of GenFit.Using the simulated data,the tracking performance was studied.The results showed that both the reconstruction resolution and tracking efficiency satisfied the requirements of the CEPC experiment.
基金supported by the National Key R&D Program of China(Nos.2022YFA1602402,2020YFE0202001,2023YFA1606900)the National Natural Science Foundation of China(NSFC)(Nos.12235003,11835002,11925502,11705031,12275053,12147101).
文摘Active target time projection chambers are state-of-the-art tools in the field of low-energy nuclear physics and are particularly suitable for experiments using low-intensity radioactive ion beams or gamma rays.The Fudan multi-purpose active target time projection chamber(fMeta-TPC)with 2048 channels was developed to studyα-clustering nuclei.This study focused on the photonuclear reaction with a laser Compton scattering gamma source,particularly for the decay of the highly excitedαcluster state.The design of fMeta-TPC is described in this paper.A comprehensive evaluation of its offline performance was conducted using an ultraviolet laser and ^(241)Amαsource.The results showed that the intrinsic angular resolution of the detector was within 0.30°,and the detector had an energy resolution of 6.85%for 3.0 MeVαparticles.The gain uniformity of the detector was approximately 10%(RMS/Mean),as tested by the ^(55)Fe X-ray source.
基金supported by the Scientific Research Foundation of Xijing University,China(No.XJ19T03)the Opening Project of Science and Technology on Reliability Physics and Application Technology of Electronic Component Laboratory(No.ZHD201701)the Natural Science Basic Research Plan in Shaanxi Province of China(No.2024JC-YBMS-342).
文摘Enhancing plasma uniformity can be achieved by modifying coil and chamber structures in radio frequency inductively coupled plasma(ICP)to meet the demand for large-area and uniformly distributed plasma in industrial manufacturing.This study utilized a two-dimensional self-consistent fluid model to investigate how different coil configurations and chamber aspect ratios affect the radial uniformity of plasma in radio frequency ICP.The findings indicate that optimizing the radial spacing of the coil enhances plasma uniformity but with a reduction in electron density.Furthermore,optimizing the coil within the ICP reactor,using the interior point method in the Interior Point Optimizer significantly enhances plasma uniformity,elevating it from 56%to 96%within the range of the model sizes.Additionally,when the chamber aspect ratio k changes from 2.8 to 4.7,the plasma distribution changes from a center-high to a saddleshaped distribution.Moreover,the plasma uniformity becomes worse.Finally,adjusting process parameters,such as increasing source power and gas pressure,can enhance plasma uniformity.These findings contribute to optimizing the etching process by improving plasma radial uniformity.
基金supported by the Youth Science Foundation of Sichuan Province(Nos.2022NSFSC1230 and 2022NSFSC1231)the Science and Technology Innovation Seedling Project of Sichuan Province(No.MZGC20230080)+1 种基金the General project of the National Natural Science Foundation of China(No.12075039)the Key project of the National Natural Science Foundation of China(No.U19A2086)。
文摘A dedicated weak current measurement system was designed to measure the weak currents generated by the neutron ionization chamber.This system incorporates a second-order low-pass filter circuit and the Kalman filtering algorithm to effectively filter out noise and minimize interference in the measurement results.Testing conducted under normal temperature conditions has demonstrated the system's high precision performance.However,it was observed that temperature variations can affect the measurement performance.Data were collected across temperatures ranging from -20 to 70℃,and a temperature correction model was established through linear regression fitting to address this issue.The feasibility of the temperature correction model was confirmed at temperatures of -5 and 40℃,where relative errors remained below 0.1% after applying the temperature correction.The research indicates that the designed measurement system exhibits excellent temperature adaptability and high precision,making it particularly suitable for measuring weak currents.
文摘Cancer is a major societal public health and economic problem, responsible for one in every six deaths. Radiotherapy is the main technique of treatment for more than half of cancer patients. To achieve a successful outcome, the radiation dose must be delivered accurately and precisely to the tumor, within ± 5% accuracy. Smaller uncertainties are required for better treatment outcome. The objective of the study is to investigate the uncertainty of measurement of external radiotherapy beam using a standard ionization chamber under reference conditions. Clinical farmers type ionization chamber measurement was compared against the National Reference standard, by exposing it in a beam 60Co gamma source. The measurement set up was carried out according to IAEA TRS 498 protocol and uncertainty of measurement evaluated according to GUM TEDDOC-1585. Evaluation and analysis were done for the identified subjects of uncertainty contributors. The expanded uncertainty associated with 56 mGy/nC ND,W was found to be 0.9% corresponding to a confidence level of approximately 95% with a coverage factor of k = 2. The study established the impact of dosimetry uncertainty of measurement in estimating external radiotherapy dose. The investigation established that the largest contributor of uncertainty is the stability of the ionization chamber at 36%, followed by temperature at 22% and positioning of the chamber in the beam at 8%. The effect of pressure, electrometer, resolution, and reproducibility were found to be minimal to the overall uncertainty. The study indicate that there is no flawless measurement, as there are many prospective sources of variation. Measurement results have component of unreliability and should be regarded as best estimates of the true value. .
文摘Objective:To explore the corrective effect of posterior chamber intraocular lens implantation with phakic eyes in the treatment of high myopia and astigmatism.Methods:From May 2023,the hospital began to collect the case data of diagnosis and treatment of high myopia and astigmatism.By May 2024,310 cases were included,all of which were treated with posterior chamber intraocular lens implantation.The visual acuity,astigmatism and axial position of the intraocular lens were observed before and after treatment.Results:At different time points after the operation,the patient’s vision was significantly improved compared with that before the operation(P<0.05),and the vision level was equal to or greater than the best-corrected vision before the operation.At different time points after the operation,the average rotation of the intraocular lens was less than 5 degrees.Astigmatism was significantly lower than that before the operation(P<0.05).After the operation,the intraocular pressure increased in 11 cases,accounting for 3.55%,with no adverse complications such as lens turbidity,glare and obvious halo occurring.Conclusion:The posterior chamber intraocular lens implantation with phakic eyes has an ideal correction effect in the treatment of high myopia and astigmatism,which can effectively improve the vision level of patients and reduce the degree of astigmatism,and has high effectiveness and safety.
文摘The impacts of different 03 concentration on the biomass and yield of rice were studied by using OTC-1 open-top chambers. Experimental treatments included the activated charcoal-filtered air. (CFA), 50 nl/L (CF50), 100 nl/L ( CF100) and 200 nl/L (CF200) concentrations of O-3. The O-3 treatments significantly decreased the total biomass per plant. The. elevated O-3 exposure resulted in a more decrease in the root growth than in the shoot growth. Assessments of yield characteristics at the final harvest revealed an O-3-induced decrease in the number of grains per plant, resulting from fewer ears per plant, fewer grains per ear and more unfilled grains per ear. The 1000 grain dry weight and the harvest index (HI) were not changed significantly under 50 nl/L or 100 nl/L O-3 exposure, but reduced by 17.0% and 4.8% by 200nl/L O-3 treatment, respectively. Compared to the CFA treatment, CF50, CF100 and CF200 treatments caused a 8.2%, 26.1%, 49.1% decrease of the grain yield per plant, and a 14.2%, 31.7%, 51.7% decrease of the total biomass per plant, respectively. Linear regression showed that the 7h - daily mean O-3 concentration exposure for 3 months ( July-September) and AOT40 ( cunulative exposure accumulation over threshold 40 nl/L) were well correlated with the relative grain yield. A yield loss of 10% was estimated to be at 46.9 nl/L O-3 for 7h-daily mean O-3 concentration exposure or at 12930nl/(L(.)h) O-3 for AOT40.
基金supported by National Natural Science Foundation of China(No.62090015,No.61821001)BUPT Excellent Ph.D.Students Foundation under Grant(CX2021216)。
文摘In this article,novel emulation strategies for the sectored multiple probe anechoic chamber(SMPAC)are proposed to enable the reliable evaluation of the massive multiple-input multiple-output(MIMO)device operating at beamforming mode,which requires a realistic non-stationary channel environment.For the dynamic propagation emulation,an efficient closed-form probe weighting strategy minimizing the power angular spectrum(PAS)emulation errors is derived,substantially reducing the associated computational complexity.On the other hand,a novel probe selection algorithm is proposed to reproduce a more accurate fading environment.Various standard channel models and setup configurations are comprehensively simulated to validate the capacity of the proposed methods.The simulation results show that more competent active probes are selected with the proposed method compared to the conventional algorithms.Furthermore,the derived closedform probe weighting strategy offers identical accuracy to that obtained with complicated numerical optimization.Moreover,a realistic dynamic channel measured in an indoor environment is reconstructed with the developed methodologies,and 95.6%PAS similarity can be achieved with 6 active probes.The satisfactory results demonstrate that the proposed algorithms are suitable for arbitrary channel emulation.
基金Supported by National Institute for Medical Research Development(NIMAD)affiliated with the Iranian Ministry of Health and Medical Education(No.963660).
文摘AIM:To determine the normative distribution of axial length(AL),anterior chamber depth(ACD),anterior chamber volume(ACV),anterior chamber angle(ACA),and some of their associated factors in subjects aged 60 and over.METHODS:In this cross-sectional study,160 clusters were sampled using multi-stage cluster sampling in Tehran,Iran.After a preliminary interview,the participants underwent optometric examinations including visual acuity and refraction measurement followed by slit lamp biomicroscopy.Finally,ocular imaging was done using the Pentacam AXL to measure AL,ACD,ACV,and ACA.RESULTS:A total of 4519 eyes of 2436 participants were evaluated,of whom 58.0%(n=1412)were female.The mean age of the subjects was 67.32±6.05y(range:60-95y).The mean AL,ACD,ACV,and ACA was 23.22 mm(23.18-23.27 mm),2.61 mm(2.59-2.62 mm),126.56 mm3(125.08-128.04 mm3),and 30.61°(30.3°-30.92°),respectively.In the multivariable model,after adjusting for the effect of both eyes,the longest and shortest AL was seen in myopic and hyperopic subjects,respectively.AL,ACD,ACV and ACA were significantly larger in men compared to women(P<0.001).Except ACA,other evaluated parameters showed an inverse correlation with age(P<0.001),however,this correlation was insignificant for AL(P=0.623).CONCLUSION:Normative value of AL,and other biometric parameters are specific for each ethnicity,age and sex group.Any alteration in these parameters and their effect on refraction should be considered in this age group,especially in case of cataract surgery.
基金Supported by the Program for Zhejiang Leading Talent of S&T Innovation(No.2021R52012)Key Research and Development Projects of Zhejiang Province(No.2022C03112)the Basic Scientific Research Program of Wenzhou(No.Y2020365).
文摘AIM:To describe the outcome of using low-dose laser cycloplasty(LCP)in chronic angle-closure glaucoma(CACG).METHODS:A retrospective case series.Medical charts of CACG patients who underwent LCP in the Eye Hospital of Wenzhou Medical University were reviewed.The main outcomes included intraocular pressure(IOP),the number of glaucoma medication,anterior segment parameters and surgery-related complications.RESULTS:A total of 7 eyes of 7 CACG patients(age 38.9±11.0y)underwent LCP with a mean follow-up of 27.1±13.7mo(range 16-48mo).Following LCP,mean IOP and glaucoma medications decreased from 26.1±6.1 mm Hg with 3.1±1.1 glaucoma medications pre-treatment to 14.9±3.1 mm Hg(P=0.027)with 0.4±1.1 glaucoma medications(P=0.001)at final follow-up.The anterior chamber depth(ACD),angle opening distance500 and trabecular-iris angle increased from 1.65±0.33 mm,0.05 mm(range 0-0.30 mm)and 5.1°(range,0-31.97°)at baseline to 1.98±0.43 mm(P=0.073),0.53 mm(range 0.42-0.91 mm,P=0.015),45.9°(range,40.2°-59.4°),(P=0.015)in the long-term follow-up,respectively.The deepening of ACD and reopening of anterior chamber angle(ACA)was observed in 6 eyes(85.7%).CONCLUSION:LCP is a promising treatment option for patients with CACG via reducing IOP and glaucoma medication without serious complications.In addition,LCP can bring a significant deepening in ACD and reopening of ACA.
基金supported by the Tianjin Synthetic Biotechnology Innovation Capacity Improvement Project (TSBICIP-KJGG003)Qinglan Plan of the Jiangsu Education Department。
文摘Hydrogen peroxide synthesis by electro-reduction of O_(2) to substitute the current anthraquinone process has attracted a great deal of attention. Low oxygen utilization rate and low hydrogen peroxide production remain obstacles to electro-Fenton application. In situ H_(2)O_(2) generated by electrochemical reaction depends on the electrochemical performance of the cathode and the structure of the reactor. Here, novel graphite felt(GF) modified by La-doped CeO_(2)(La-CeO_(2)) was developed as a cathode. A new double chamber electro-Fenton reactor was proposed, where an organic ultrafiltration membrane was used to prevent H_(2)O_(2) from spreading to the anode. The effects of hydrothermal temperature, time and urea concentration on the electrochemical properties of graphite felt were investigated. The accumulated concentration of H_(2)O_(2) on the modified cathode reached 218.4 mg·L^(-1)in 1 h when the optimal conditions of hydrothermal temperature 120 ℃ and urea concentration 0.55%(mass) in 24 h. The degradation rate of methyl orange reached 98.29%. The new electro-Fenton reactor can efficiently produce hydrogen peroxide to degrade various organic substances and has a high potential for treating wastewater in the chemical industry.
基金Supported by the National Natural Science Foundation of China (No.81770972,No.81970843)。
文摘AIM:To evaluate the postoperative refractive prediction error(PE)and determine the factors that af fect the refractive outcomes of combined pars plana vitrectomy(PPV)or silicone oil removal(SOR)with cataract surgery.METHODS:The study is a retrospective,case-series study.Totally 301 eyes of 301 patients undergoing combined PPV/SOR with cataract surgery were enrolled.Eligible individuals were separated into four groups according to their preoperative diagnoses:silicone oil-filled eyes after PPV(group 1),epiretinal membrane(group 2),macular hole(group 3),and primary retinal detachment(RD;group 4).The variables af fecting postoperative refractive outcomes were analyzed,including age,gender,preoperative best-corrected visual acuity(BCVA),axial length(AL),keratometry average,anterior chamber depth(ACD),intraocular tamponade,and vitreoretinal pathology.The outcome measurements include the mean refractive PE and the proportions of eyes with a PE within±0.50 diopter(D)and±1.00 D.RESULTS:For all patients,the mean PE was-0.04±1.17 D,and 50.17%of patients(eyes)had a PE within±0.50 D.There was a significant difference in refractive outcomes among the four groups(P=0.028),with RD(group 4)showing the least favorable refractive outcome.In multivariate regression analysis,only AL,vitreoretinal pathology,and ACD were strongly associated with PE(all P<0.01).Univariate analysis revealed that longer eyes(AL>26 mm)and a deeper ACD were correlated with hyperopic PE,and shorter eyes(AL<26 mm)and a shallower ACD were correlated with myopic PE.CONCLUSION:RD patients have the least favorable refractive outcome.AL,vitreoretinal pathology,and ACD are strongly associated with PE in the combined surgery.These three factors affect refractive outcomes and thus can be used to predict a better postoperative refractive outcome in clinical practice.
文摘The results of analysis of technical possibilities to increase engine efficiency were presented in this article. This problem was connected with kinematics properties of air inflow to the combustion chamber. The possibilities of intake airflow modulation have a positive impact on combustion process, level of engine usable parameters and emission. This issue was presented on the results of experimental research. Results of baseline research gave information about the flow resistance. On the basis of results of experimental research, conclusions were formulated.
文摘Contaminated or infected patients present a risk of cross-contamination for emergency responders, attending medical personnel and medical facilities as they enter a treatment facility. The controlled conditions of an aerosol test chamber are required to examine factors of contamination, decontamination, and cross-contamination. This study presents the design, construction, and a method for characterizing an aerosol test chamber for a full-sized manikin on a standard North Atlantic Treaty Organization litter. The methodology combined air velocity measurements, aerosol particle counts and size distributions, and computational fluid dynamics modeling to describe the chamber’s performance in three dimensions. This detailed characterization facilitates future experimental design by predicting chamber performance for a variety of patient-focused research.
文摘Radon is the most important source of natural radiation to human beings and the second major causative agent of lung cancer other than smoking. In recent years, the hazards of human exposure to thoron (Rn-220), another isotope of radon, and its progeny have gained consensus. To accurately evaluate the dose level and hazards of Rn-220 and its progeny, a standard Rn-220 chamber with strong regulation ability for Rn-220 and its progeny needs to be established for the scale or calibration of measurement instruments. This paper describes the hazards, sources, behavioral characteristics of Rn-220 and its progeny, and some representative Rn-220 chambers established in various countries.
文摘Background: The burden of cataract and glaucoma has been increasing. Primary angle closure occurs as a result of crowded anterior segment anatomy causing appositional contact between peripheral iris and trabecular meshwork. Lens extraction has been proposed as a method of deepening anterior chamber and managing intraocular pressure. Purpose: To assess changes in anterior chamber depth after phacoemulsification with intraocular lens implantation in narrow angle eyes. Design: Prospective controlled trial (before-after) study. Method: The study was conducted from March 2015 to August 2017 among the patients of department of Ophthalmology of BSMMU who were diagnosed as cataract with narrow angles. Anterior chamber angle grading of 2 or less (Shaffer grading) in 3 or more quadrants was considered narrow angle (NA). The purposive type sampling technique was applied to collect sample from the study population, as per inclusion and exclusion criteria. Complete clinical evaluation including history, physical examination, relevant ocular examinations and systemic examinations were performed. In this prospective study, subjects underwent phacoemulsification with foldable lens implantation. A scan ultrasonography was performed preoperatively and 10<sup>th</sup> and 30<sup>th</sup> postoperative days of surgery. Results: Thirty eyes of 29 patients included in the study, male: female ratio was 1:1, with an overall mean age of 62.03 ± 8.95 years. The mean preoperative central ACD was 2.95 ± 0.35 mm. At 10<sup>th</sup> and 30<sup>th</sup> POD mean central ACD were 3.94 ± 0.32, and 3.92 ± 0.28 mm respectively. Mean of increase in central ACD at final follow-up was 0.96 mm (p Conclusion: Phacoemulsification with posterior chamber in bag lens implantation can deepen the anterior chamber depth in patients with narrow angles. Based on these findings, it is concluded that phacoemulsification with foldable intraocular lens implantation is an effective tool in deepening the anterior chamber.
基金National Natural Science Foundation of China(No.62173307)the Key R&D Projects of Science and Technology Department of Zhejiang Province,China(Nos.2023C01158,2022C01065 and 2022C01188)the Fundamental Research Funds of Zhejiang Sci-Tech University,China(No.22242298-Y)。
文摘The plenum chamber of a heat setting machine is a key structure for distributing hot air to different air channels.Its outlet velocity uniformity directly determines the heating uniformity of textiles,significantly affecting the heat setting performance.In a traditional heat setting machine,the outlet airflow maldistribution of the plenum chamber still exists.In this study,a novel plenum chamber with an airfoil baffle was established to improve the uniformity of the velocity distribution at the outlet in a heat setting machine.The structural influence of the plenum chamber on the velocity distribution was investigated using a computational fluid dynamics program.It was found that a chamber with a smaller outlet partition thickness had a better outlet velocity uniformity.The structural optimization of the plenum chamber was conducted using the particle swarm optimization algorithm.The outlet partition thickness,the transverse distance and the longitudinal distance of the optimized plenum chamber were 20,686.2 and 274.6 mm,respectively.Experiments were carried out.The experimental and simulated results showed that the optimized plenum chamber with an airfoil baffle could improve the outlet velocity uniformity.The air outlet velocity uniformity index of the optimized plenum chamber with an airfoil baffle was 4.75%higher than that of the plenum chamber without an airfoil baffle and 5.98%higher than that of the conventional chamber with a square baffle in a commercial heat setting machine.
基金The National Natural Science Foundation of China under contract Nos 42130410,41876075 and U1906210the Fundamental Research Funds for the Central Universities under contract No.201962003.
文摘Radon(Rn)is a naturally occurring radioactive inert gas in nature,and^(222)Rn has been routinely used as a powerful tracer in various aquatic environmental research on timescales of hours to days,such as submarine groundwater discharge.Here we developed a new approach to measure^(222)Rn in discrete water samples with a wide range of^(222)Rn concentrations using a Pulsed Ionization Chamber(PIC)Radon Detector.The sensitivity of the new PIC system is evaluated at 6.06 counts per minute for 1 Bq/L when a 500 mL water sample volume is used.A robust logarithmic correlation between sample volumes,ranging from 250 mL to 5000 mL,and system sensitivity obtained in this study strongly suggests that this approach is suitable for measuring radon concentration levels in various natural waters.Compared to the currently available methods for measuring radon in grab samples,the PIC system is cheaper,easier to operate and does not require extra accessories(e.g.,drying tubes etc.)to maintain stable measurements throughout the counting procedure.
基金jointly funded by the Marine S&T Fund of Shandong Province for the Pilot National Laboratory for Marine Science and Technology (Qingdao)(2022QNLM 040003-3)the National Key R&D Program of China (2016YFE0109600)+3 种基金National Natural Science Foundation of China (U22A20558, 41240022, 41876057, 40872167, 41602143)China Geological Survey (1212010611402, GZH201200503, and DD20160144)by in-kind support from the Land Carbon ProgramLand Change Science R&D Program of the United States Geological Survey。
文摘Passive-warming, open-top chambers(OTCs) are widely applied for studying the effects of future climate warming on coastal wetlands. In this study, a set of six OTCs were established at a Phragmites wetland located in the Yellow River Delta of Dongying City, China. With data collected through online transmission and in-situ sensors, the attributes and patterns of realized OTCs warming are demonstrated.The authors also quantified the preliminary influence of experimental chamber warming on plant traits.OTCs produced an elevated average air temperature of 0.8°C(relative to controls) during the growing season(June to October) of 2018, and soil temperatures actually decreased by 0.54°C at a depth of 5 cm and 0.46°C at a depth of 30 cm in the OTCs. Variations in diel patterns of warming depend greatly on the heat sources of incoming radiation in the daytime versus soil heat flux at night. Warming effects were often larger during instantaneous analyses and influenced OTCs air temperatures from-2.5°C to 8.3°C dependent on various meteorological conditions at any given time, ranging from cooling influences from vertical heat exchange and vegetation to radiation-associated warming. Night-time temperature depressions in the OTCs were due to the low turbulence inside OTCs and changes in surface soilatmosphere heat transfer. Plant shoot density, basal diameter, and biomass of Phragmites decreased by23.2%, 6.3%, and 34.0%, respectively, under experimental warming versus controls, and plant height increased by 4.3%, reflecting less carbon allocation to stem structures as plants in the OTCs experienced simultaneous wind buffering. While these passive-warming OTCs created the desired warming effects both to the atmosphere and soils, pest damages on the plant leaves and lodging within the OTCs were extensive and serious, creating the need to consider control options for these chambers and the replicated OTCs studies underway in other Chinese Phragmites marshes(Panjin and Yancheng).
