The application of nitrogen fertilizers in agricultural fields can lead to the release of nitrogen-containing gases(NCGs),such as NO_(x),NH_(3) and N_(2)O,which can significantly impact regional atmospheric environmen...The application of nitrogen fertilizers in agricultural fields can lead to the release of nitrogen-containing gases(NCGs),such as NO_(x),NH_(3) and N_(2)O,which can significantly impact regional atmospheric environment and con-tribute to global climate change.However,there remain considerable research gaps in the accurate measurement of NCGs emissions from agricultural fields,hindering the development of effective emission reduction strategies.We improved an open-top dynamic chambers(OTDCs)system and evaluated the performance by comparing the measured and given fluxes of the NCGs.The results showed that the measured fluxes of NO,N_(2)O and NH_(3)were 1%,2%and 7%lower than the given fluxes,respectively.For the determination of NH_(3) concentration,we employed a stripping coil-ion chromatograph(SC-IC)analytical technique,which demonstrated an absorption efficiency for atmospheric NH_(3) exceeding 96.1%across sampling durations of 6 to 60 min.In the summer maize season,we utilized the OTDCs system to measure the exchange fluxes of NO,NH_(3),and N_(2)O from the soil in the North China Plain.Substantial emissions of NO,NH_(3) and N_(2)O were recorded following fertilization,with peaks of 107,309,1239 ng N/(m^(2)·s),respectively.Notably,significant NCGs emissions were observed following sus-tained heavy rainfall one month after fertilization,particularly with NH_(3) peak being 4.5 times higher than that observed immediately after fertilization.Our results demonstrate that the OTDCs system accurately reflects the emission characteristics of soil NCGs and meets the requirements for long-term and continuous flux observation.展开更多
In a rapid cycling synchrotron(RCS),the magnetic field is synchronized with the beam energy,creating a highly dynamic magnetic environment.A ceramic chamber with a shielding layer(RF shield),composed of a series of co...In a rapid cycling synchrotron(RCS),the magnetic field is synchronized with the beam energy,creating a highly dynamic magnetic environment.A ceramic chamber with a shielding layer(RF shield),composed of a series of copper strips connected to a capacitor at either end,is typically employed as a vacuum chamber to mitigate eddy current effects and beam coupling impedance.Consequently,the ceramic chamber exhibits a thin-walled multilayered complex structure.Previous theoretical studies have suggested that the impedance of such a structure has a negligible impact on the beam.However,recent impedance measurements of the ceramic chamber in the China Spallation Neutron Source(CSNS)RCS revealed a resonance in the low-frequency range,which was confirmed by further theoretical analysis as a source of beam instability in the RCS.Currently,the magnitude of this impedance cannot be accurately assessed using theoretical calculations.In this study,we used the CST Microwave Studio to confirm the impedance of the ceramic chamber.Further simulations covering six different types of ceramic chambers were conducted to develop an impedance model in the RCS.Additionally,this study investigates the resonant characteristics of the ceramic chamber impedance,finding that the resonant frequency is closely related to the capacitance of the capacitors.This finding provides clear directions for further impedance optimization and is crucial for achieving a beam power of 500 kW for the CSNS Phase-Ⅱ project(CSNS-Ⅱ).However,careful attention must be paid to the voltage across the capacitors.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
AIM:To identify topographic determinants of the anterior chamber angle(ACA)in patients with keratoconus(KCN).METHODS:Four hundred and ten eyes of 294 patients with KCN were recruited for this study.First,complete ocul...AIM:To identify topographic determinants of the anterior chamber angle(ACA)in patients with keratoconus(KCN).METHODS:Four hundred and ten eyes of 294 patients with KCN were recruited for this study.First,complete ocular examinations were performed for all patients,including visual acuity measurement,refraction,and slit-lamp biomicroscopy.Then,all participants underwent corneal imaging by the Oculus Pentacam HR.RESULTS:The mean age of the participants was 32.40±8.52y(15-60y)and 69.5%of them were male.The mean ACA was 38.47°±5.75°(range:14.40°to 56.50°)in the whole sample,38.24°±6.00°in males,and 38.98°±5.11°in females(P=0.447).The mean ACA was significantly different among different groups of cone morphology,as patients with nipple cones showed the lowest mean ACA.Moreover,there were statistically significant differences in the mean ACA among different groups of cone locations,with patients having central cones exhibiting the lowest mean ACA(P<0.001).Anterior and posterior Q values were significantly,directly correlated with ACA(anterior Q:r=0.122,P=0.014,posterior Q:r=0.192,P<0.001).CONCLUSION:This study provides critical insights into the risk factors for ACA narrowing in KCN patients,which is essential for planning intraocular surgeries.Patients with nipple and central cones exhibited the most significant ACA narrowing.Additionally,more negative Q-values are associated with increased ACA narrowing,highlighting the need for targeted diagnostic and therapeutic strategies.展开更多
To fundamentally alleviate the excavation chamber clogging during slurry tunnel boring machine(TBM)advancing in hard rock,large-diameter short screw conveyor was adopted to slurry TBM of Qingdao Jiaozhou Bay Second Un...To fundamentally alleviate the excavation chamber clogging during slurry tunnel boring machine(TBM)advancing in hard rock,large-diameter short screw conveyor was adopted to slurry TBM of Qingdao Jiaozhou Bay Second Undersea Tunnel.To evaluate the discharging performance of short screw conveyor in different cases,the full-scale transient slurry-rock two-phase model for a short screw conveyor actively discharging rocks was established using computational fluid dynamics-discrete element method(CFD-DEM)coupling approach.In the fluid domain of coupling model,the sliding mesh technology was utilized to describe the rotations of the atmospheric composite cutterhead and the short screw conveyor.In the particle domain of coupling model,the dynamic particle factories were established to produce rock particles with the rotation of the cutterhead.And the accuracy and reliability of the CFD-DEM simulation results were validated via the field test and model test.Furthermore,a comprehensive parameter analysis was conducted to examine the effects of TBM operating parameters,the geometric design of screw conveyor and the size of rocks on the discharging performance of short screw conveyor.Accordingly,a reasonable rotational speed of screw conveyor was suggested and applied to Jiaozhou Bay Second Undersea Tunnel project.The findings in this paper could provide valuable references for addressing the excavation chamber clogging during ultra-large-diameter slurry TBM tunneling in hard rock for similar future.展开更多
AIM:To measure the optimal anterior chamber pressure(ACP)for safe phacoemulsification using a new tube chamber system with internal pressure measurement function in the porcine eye.METHODS:The 20-gauge and 21-gauge st...AIM:To measure the optimal anterior chamber pressure(ACP)for safe phacoemulsification using a new tube chamber system with internal pressure measurement function in the porcine eye.METHODS:The 20-gauge and 21-gauge straight tips with yellow and orange sleeves,respectively,were covered by a test chamber combined with a pressure sensor for measuring ACP.This was measured for 20s from 10s after starting aspiration in the linear mode using vacuum levels of 200 and 150 mm Hg with a 20-gauge tip,and 300 and 250 mm Hg with a 21-gauge tip.Using a porcine eye,a pressure sensor fixed with a 0.9 mm corneal incision measured ACP.For the posterior capsule contact assay,porcine eyes were treated as described above,and the ultrasonic needle tip was held at the height of the iris and aspirated for 30s in linear mode at a vacuum of 200 and 150 mm Hg for the 20-gauge tip,and 300 and 250 mm Hg for the 21-gauge tip.The bottle height at which the posterior capsule accidentally contacted the ultrasonic tip was recorded,and the estimated ACP was calculated.RESULTS:The internal pressure of the new tube chamber system and ACP from the porcine eye closely matched proportional changes at vacuum levels of 200 and 150 mm Hg with 20-gauge tips.Similarly,proportional changes at vacuum levels of 300 and 250 mm Hg with the 21-gauge tip were nearly equal.The bottle height at which the posterior capsule contacted with the tip and estimated ACP were 57.5±12.6 cm(20.2±7.9 mm Hg)at 200 mm Hg with a 20-gauge tip,35.0±10.0 cm(16.6±6.3 mm Hg)at 150 mm Hg with a 20-gauge tip,47.5±12.6 cm(18.7±8.7 mm Hg)at 300 mm Hg with a 21-gauge tip,and 32.5±5.0 cm(15.7±3.5 mm Hg)at 250 mm Hg with a 21-gauge tip.CONCLUSION:A comprehensive understanding of this chamber system’s characteristics and usage can resolve anterior chamber instability caused by changing preoperative settings on the phaco machine.展开更多
On January 11,2025,the 2025 Bejing Roundtable Meeting for International Exhibition Organisations was held in Beijing.The event was co-hosted by the CCPIT Bejing,the Bejing Municipal Commerce Bureau,the Shunyi District...On January 11,2025,the 2025 Bejing Roundtable Meeting for International Exhibition Organisations was held in Beijing.The event was co-hosted by the CCPIT Bejing,the Bejing Municipal Commerce Bureau,the Shunyi District People's Government and the Beijing Chamber of International Commerce.展开更多
James Joyce’s poetry collection, Chamber Music, which he defines as “chambermade music,” epitomizes his literary pursuit of musicality and resonates with his dual identity as both a lyric poet and an Irishman. Musi...James Joyce’s poetry collection, Chamber Music, which he defines as “chambermade music,” epitomizes his literary pursuit of musicality and resonates with his dual identity as both a lyric poet and an Irishman. Musicality in Chamber Music can first be seen in allusions to musical elements which contribute to the musical revelation of emotions. Furthermore, repetition pervades Chamber Music both in themes and structure, resonating with the cyclical nature of Irish music. Under the influence of the Irish Revival, Joyce creatively navigates the realm of musical lyrics, draws a balance between English and Irish traditions, and provides a seminal model for his further exploration of musical writing in his later masterpieces.展开更多
EMC anechoic chamber is used for radiation emission and radiation immunity test,and the wireless performance of products needs to be tested in OTA anechoic chamber.With more and more electronic and electrical equipmen...EMC anechoic chamber is used for radiation emission and radiation immunity test,and the wireless performance of products needs to be tested in OTA anechoic chamber.With more and more electronic and electrical equipment with wireless communication function,the rapid construction of a compatible OTA test system in the existing EMC anechoic chamber can save the cost and space of enterprises and third-party laboratories that already have EMC anechoic chamber.In this paper,the OTA test system is built in the existing EMC anechoic room,the ripple calibration test is carried out according to the OTA standard,the TRP and TIS tests are carried out on two test samples with different wireless communication standards,and the test samples are taken to the OTA anechoic room for a comparison test.The comparison between the ripple calibration data and the OTA test data showed that the EMC anechoic chamber could perform OTA test without affecting the original test ability.The data results provide a basis for the implementation of EMC anechoic chamber compatibility upgrade OTA test,and provide reference for further optimization of the compatible test system,reduction of test differences,and the design of anechoic chamber integrating two test functions.展开更多
The particle identification(PID)of hadrons plays a crucial role in particle physics experiments,especially in flavor physics and jet tagging.The cluster counting method,which measures the number of primary ionizations...The particle identification(PID)of hadrons plays a crucial role in particle physics experiments,especially in flavor physics and jet tagging.The cluster counting method,which measures the number of primary ionizations in gaseous detectors,is a promising breakthrough in PID.However,developing an effective reconstruction algorithm for cluster counting remains challenging.To address this challenge,we propose a cluster counting algorithm based on long short-term memory and dynamic graph convolutional neural networks for the CEPC drift chamber.Experiments on Monte Carlo simulated samples demonstrate that our machine learning-based algorithm surpasses traditional methods.It improves the K/πseparation of PID by 10%,meeting the PID requirements of CEPC.展开更多
Angela Carter’s short story,The Bloody Chamber,was created by rewriting the fairy tale Bluebeard,which expressed her strong feminist views.Based on the theory of spatial criticism,this paper is meant to interpret the...Angela Carter’s short story,The Bloody Chamber,was created by rewriting the fairy tale Bluebeard,which expressed her strong feminist views.Based on the theory of spatial criticism,this paper is meant to interpret the growth of the heroine in The Bloody Chamber.It analyzes the nameless bride’s growth process of searching for her true self in the novel from the three levels:social space,physical space and psychological space.展开更多
Compressed air energy storage(CAES)has emerged as a grid-scale energy storage linchpin,providing diurnal-to-seasonal timescale energy buffering for renewable power integration.Diverging from conventional salt cavernde...Compressed air energy storage(CAES)has emerged as a grid-scale energy storage linchpin,providing diurnal-to-seasonal timescale energy buffering for renewable power integration.Diverging from conventional salt caverndependent approaches,artificial cavern-based CAES unlocks geographical adaptability through engineered underground containment.This study systematically reviews critical technologies in chamber construction,including site selection,structural design,excavation methods,and post-construction evaluation.Site selection employs a multi-criteria matrix that combines geological and environmental factors.Structural design integrates spatial layout,burial depth,sealing system,and component compatibility to ensure chamber stability.Excavation prioritizes controlled blasting for homogeneous rock,while a tunnel boring machine is deployed in fractured zones to preserve integrity.Postconstruction assessments validate load-bearing capacity,sealing performance,and operational readiness,supported by data-driven maintenance strategies.Ongoing challenges include site-specific geological risks,sealing system durability under cyclic loading,equipment integration,field-scale validation,standardization gaps,and cost-efficiency optimization.These innovations will establish best practices for building large-scale,high-efficiency CAES plants with ultra-long duration and grid resilience,accelerating the transition to carbon-neutral power systems.展开更多
According to the World Health Organization(WHO)manual,sperm concentration should be measured using an improved Neubauer hemocytometer,while sperm motility should be measured by manual assessment.However,in China,thous...According to the World Health Organization(WHO)manual,sperm concentration should be measured using an improved Neubauer hemocytometer,while sperm motility should be measured by manual assessment.However,in China,thousands of laboratories do not use the improved Neubauer hemocytometer or method;instead,the Makler counting chamber is one of the most widely used chambers.To study sources of error that could impact the measurement of the apparent concentration and motility of sperm using the Makler counting chamber and to verify its accuracy for clinical application,67 semen samples from patients attending the Department of Andrology,West China Second University Hospital,Sichuan University(Chengdu,China)between 13 September 2023 and 27 September 2023,were included.Compared with applying the cover glass immediately,delaying the application of the cover glass for 5 s,10 s,and 30 s resulted in average increases in the sperm concentration of 30.3%,74.1%,and 107.5%,respectively(all P<0.0001)and in the progressive motility(PR)of 17.7%,30.8%,and 39.6%,respectively(all P<0.0001).However,when the semen specimens were fixed with formaldehyde,a delay in the application of the cover glass for 5 s,10 s,and 30 s resulted in an average increase in the sperm concentration of 6.7%,10.8%,and 14.6%,respectively,compared with immediate application of the cover glass.The accumulation of motile sperm due to delays in the application of the cover glass is a significant source of error with the Makler counting chamber and should be avoided.展开更多
The semicylindrical time projection chamber(scTPC)is designed to measure the angular distribution of the cross section for intermediate-energy(3He,t)charge-exchange reactions in inverse kinematics.The scTPC prototype ...The semicylindrical time projection chamber(scTPC)is designed to measure the angular distribution of the cross section for intermediate-energy(3He,t)charge-exchange reactions in inverse kinematics.The scTPC prototype comprises a cathode,field cage,drift region,amplification structure based on a multilayer thick gas electron multiplier(THGEM),and a readout plane with 886 zigzag-shaped pads.The gain uniformity of the THGEM and the drift velocity of electrons were calibrated.Track recognition based on the Hough transform was then developed to reconstruct cosmic ray tracks and determine their position resolution.The position resolution of secondary particle tracks resulting from collisions between the heavy-ion beam and the 3He target was measured,yielding an x-resolution of 0.71 mm and a z-resolution of 0.73 mm.The scTPC demonstrates sufficient energy and spatial resolution to support charge-exchange reaction experiments in inverse kinematics.展开更多
AIM:To describe the alterations of the vitreous pathology and anterior chamber(AC)angle structures following transscleral cyclophotocoagulation(TSCP)and better understand the mechanism of post-laser intraocular pressu...AIM:To describe the alterations of the vitreous pathology and anterior chamber(AC)angle structures following transscleral cyclophotocoagulation(TSCP)and better understand the mechanism of post-laser intraocular pressure(IOP)reduction in angle-closure glaucoma(ACG).METHODS:Porcine eyes ex vivo and rabbit eyes in vivo were used.In porcine eyes,permeability rates of the anterior vitreous cortex(AVC)and anterior hyaloid membrane(AHM)were assessed using Schirmer’s strips.Permeability rates in the circumlental space were compared with or without TSCP bursts.Fluorescein diffusion times from the vitreous to the AC were compared between eyes with and without TSCP.In rabbit eyes,changes in IOP and AC angle structures under ultrasound biomicroscopy(UBM)were evaluated at intervals of 30min,7d,and 14d after TSCP.Vitreous pathology was examined using scanning electron microscopy(SEM)immediately and 14d after TSCP.RESULTS:In porcine eyes(n=20),the median(range)permeability rates were 10.3(range 9.8–10.8)mm/min for the AVC and 4.3(range 3.9–4.9)mm/min for the AHM(P=0.009).Permeability rates in the circumlental space were 4.2(range 3.8–4.9)mm/min in areas without TSCP,6.2(range 5.7–6.8)mm/min in areas with non-burst TSCP,and 11.3(range 10.9–11.8)mm/min in areas with burst TSCP(P=0.002).The median(range)fluorescein diffusion time was 5(range 3–8)min in eyes undergoing TSCP,whereas it was 40min(range 35–68)in eyes without TSCP(P<0.001).In rabbit eyes(n=20),SEM showed immediate localized damage to the AHM,AVC,and posterior lens zonules in areas subjected to TSCP bursts,and obvious lens zonule loss with cellular infiltration and possible vitreous liquefaction by post-op day 14.Persistent widening of AC angles was noted at postoperative days 7 and 14,although a significant reduction in IOP was only observed at postoperative day 7.CONCLUSION:TSCP-induced damage on the zonules,AHM,and AVC potentially enhances fluid outflow from the vitreous,leading to a widened AC angle and vitreous liquefaction in rabbits.These observations offer insights into mechanisms of TSCP in lowering IOP and pathogenic roles of vitreous in ACG.展开更多
A half-size prototype of the multi wire drift chamber for the cooling storage ring external-target experiment(CEE)was assembled and tested in the 350 MeV/u Kr+Fe reactions at the heavy-ion research facility in Lanzhou...A half-size prototype of the multi wire drift chamber for the cooling storage ring external-target experiment(CEE)was assembled and tested in the 350 MeV/u Kr+Fe reactions at the heavy-ion research facility in Lanzhou.The prototype consists of six sense layers,where the sense wires are stretched in three directions X,U,and V;meeting 0?,30?,and-30?,respectively,with respect to the vertical axis.The sensitive area of the prototype is 76 cm×76 cm.The amplified and shaped signals from the anode wires were digitized in a serial capacity array.When operating at a high voltage of 1500 V on the anode wires,the efficiency for each layer is greater than 95%.The tracking residual is approximately 301±2μm.This performance satisfies the requirements of CEE.展开更多
AIM:To assess whether the implantation of a posterior chamber phakic intraocular lens produces changes in optical coherence tomography(OCT)measurements of macular thickness(MT)and two parameters that define the struct...AIM:To assess whether the implantation of a posterior chamber phakic intraocular lens produces changes in optical coherence tomography(OCT)measurements of macular thickness(MT)and two parameters that define the structure of the optic nerve,the peripapillary nerve fiber layer(RNFL)and the Bruch’s membrane opening-minimum rim width(BMO-MRW).METHODS:This nonrandomized prospective pre-post study included 86 eyes of 48 patients(age,20-47y;axial length:23.10-28.95 mm)scheduled for myopia or myopic astigmatism correction with implantation of the implantable collamer lens(ICL).Eyes with glaucoma or any other ocular disease that could alter OCT results were excluded.RNFL,BMO-MRW and MT were measured preoperatively,and at 1 and 6mo after surgery using spectral-domain OCT.Changes between preoperative and postoperative values were evaluated.RESULTS:There was a significant increase in BMOMRW at 1mo(mean change:3.48±15.07μm,P=0.041).No significant changes were found during the rest of followup(1-6mo postop.,P=0.623).There was also a significant increase in RNFL thickness at 1mo af ter surger y(1.45±2.18μm,P<0.001),but with a significant reduction from 1 to 6mo postoperatively(P=0.002).Regarding MT,it increased significantly at 1mo(2.46±3.76μm,P<0.001),with a significant decrease afterwards(P=0.048).Measurements of the three parameters at 6mo were slightly superior to preoperative values(P<0.01).CONCLUSION:Minimal changes are induced in BMOMRW,RNFL and MT after ICL implantation in healthy eyes,confirming the safety of the surgical procedure regarding the structure of the optic nerve head and the macula,and indicating that this phakic intraocular lens seems to have a slight impact on OCT measurements.展开更多
基金supported by the National Key Research and Develop-ment Program(No.2022YFC3701103)the National Natural Science Foundation of China(Nos.42130714 and 41931287).
文摘The application of nitrogen fertilizers in agricultural fields can lead to the release of nitrogen-containing gases(NCGs),such as NO_(x),NH_(3) and N_(2)O,which can significantly impact regional atmospheric environment and con-tribute to global climate change.However,there remain considerable research gaps in the accurate measurement of NCGs emissions from agricultural fields,hindering the development of effective emission reduction strategies.We improved an open-top dynamic chambers(OTDCs)system and evaluated the performance by comparing the measured and given fluxes of the NCGs.The results showed that the measured fluxes of NO,N_(2)O and NH_(3)were 1%,2%and 7%lower than the given fluxes,respectively.For the determination of NH_(3) concentration,we employed a stripping coil-ion chromatograph(SC-IC)analytical technique,which demonstrated an absorption efficiency for atmospheric NH_(3) exceeding 96.1%across sampling durations of 6 to 60 min.In the summer maize season,we utilized the OTDCs system to measure the exchange fluxes of NO,NH_(3),and N_(2)O from the soil in the North China Plain.Substantial emissions of NO,NH_(3) and N_(2)O were recorded following fertilization,with peaks of 107,309,1239 ng N/(m^(2)·s),respectively.Notably,significant NCGs emissions were observed following sus-tained heavy rainfall one month after fertilization,particularly with NH_(3) peak being 4.5 times higher than that observed immediately after fertilization.Our results demonstrate that the OTDCs system accurately reflects the emission characteristics of soil NCGs and meets the requirements for long-term and continuous flux observation.
基金supported by the Guangdong Basic and Applied Basic Research Foundation,China(No.2021B1515140007).
文摘In a rapid cycling synchrotron(RCS),the magnetic field is synchronized with the beam energy,creating a highly dynamic magnetic environment.A ceramic chamber with a shielding layer(RF shield),composed of a series of copper strips connected to a capacitor at either end,is typically employed as a vacuum chamber to mitigate eddy current effects and beam coupling impedance.Consequently,the ceramic chamber exhibits a thin-walled multilayered complex structure.Previous theoretical studies have suggested that the impedance of such a structure has a negligible impact on the beam.However,recent impedance measurements of the ceramic chamber in the China Spallation Neutron Source(CSNS)RCS revealed a resonance in the low-frequency range,which was confirmed by further theoretical analysis as a source of beam instability in the RCS.Currently,the magnitude of this impedance cannot be accurately assessed using theoretical calculations.In this study,we used the CST Microwave Studio to confirm the impedance of the ceramic chamber.Further simulations covering six different types of ceramic chambers were conducted to develop an impedance model in the RCS.Additionally,this study investigates the resonant characteristics of the ceramic chamber impedance,finding that the resonant frequency is closely related to the capacitance of the capacitors.This finding provides clear directions for further impedance optimization and is crucial for achieving a beam power of 500 kW for the CSNS Phase-Ⅱ project(CSNS-Ⅱ).However,careful attention must be paid to the voltage across the capacitors.
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 Iranian University of Medical Sciences(code:IR.IUMS.REC.1401.371).
文摘AIM:To identify topographic determinants of the anterior chamber angle(ACA)in patients with keratoconus(KCN).METHODS:Four hundred and ten eyes of 294 patients with KCN were recruited for this study.First,complete ocular examinations were performed for all patients,including visual acuity measurement,refraction,and slit-lamp biomicroscopy.Then,all participants underwent corneal imaging by the Oculus Pentacam HR.RESULTS:The mean age of the participants was 32.40±8.52y(15-60y)and 69.5%of them were male.The mean ACA was 38.47°±5.75°(range:14.40°to 56.50°)in the whole sample,38.24°±6.00°in males,and 38.98°±5.11°in females(P=0.447).The mean ACA was significantly different among different groups of cone morphology,as patients with nipple cones showed the lowest mean ACA.Moreover,there were statistically significant differences in the mean ACA among different groups of cone locations,with patients having central cones exhibiting the lowest mean ACA(P<0.001).Anterior and posterior Q values were significantly,directly correlated with ACA(anterior Q:r=0.122,P=0.014,posterior Q:r=0.192,P<0.001).CONCLUSION:This study provides critical insights into the risk factors for ACA narrowing in KCN patients,which is essential for planning intraocular surgeries.Patients with nipple and central cones exhibited the most significant ACA narrowing.Additionally,more negative Q-values are associated with increased ACA narrowing,highlighting the need for targeted diagnostic and therapeutic strategies.
基金supported by the Fundamental Research Funds for the Central Universities(Grant No.2023YJS053)the National Natural Science Foundation of China(Grant No.52278386).
文摘To fundamentally alleviate the excavation chamber clogging during slurry tunnel boring machine(TBM)advancing in hard rock,large-diameter short screw conveyor was adopted to slurry TBM of Qingdao Jiaozhou Bay Second Undersea Tunnel.To evaluate the discharging performance of short screw conveyor in different cases,the full-scale transient slurry-rock two-phase model for a short screw conveyor actively discharging rocks was established using computational fluid dynamics-discrete element method(CFD-DEM)coupling approach.In the fluid domain of coupling model,the sliding mesh technology was utilized to describe the rotations of the atmospheric composite cutterhead and the short screw conveyor.In the particle domain of coupling model,the dynamic particle factories were established to produce rock particles with the rotation of the cutterhead.And the accuracy and reliability of the CFD-DEM simulation results were validated via the field test and model test.Furthermore,a comprehensive parameter analysis was conducted to examine the effects of TBM operating parameters,the geometric design of screw conveyor and the size of rocks on the discharging performance of short screw conveyor.Accordingly,a reasonable rotational speed of screw conveyor was suggested and applied to Jiaozhou Bay Second Undersea Tunnel project.The findings in this paper could provide valuable references for addressing the excavation chamber clogging during ultra-large-diameter slurry TBM tunneling in hard rock for similar future.
文摘AIM:To measure the optimal anterior chamber pressure(ACP)for safe phacoemulsification using a new tube chamber system with internal pressure measurement function in the porcine eye.METHODS:The 20-gauge and 21-gauge straight tips with yellow and orange sleeves,respectively,were covered by a test chamber combined with a pressure sensor for measuring ACP.This was measured for 20s from 10s after starting aspiration in the linear mode using vacuum levels of 200 and 150 mm Hg with a 20-gauge tip,and 300 and 250 mm Hg with a 21-gauge tip.Using a porcine eye,a pressure sensor fixed with a 0.9 mm corneal incision measured ACP.For the posterior capsule contact assay,porcine eyes were treated as described above,and the ultrasonic needle tip was held at the height of the iris and aspirated for 30s in linear mode at a vacuum of 200 and 150 mm Hg for the 20-gauge tip,and 300 and 250 mm Hg for the 21-gauge tip.The bottle height at which the posterior capsule accidentally contacted the ultrasonic tip was recorded,and the estimated ACP was calculated.RESULTS:The internal pressure of the new tube chamber system and ACP from the porcine eye closely matched proportional changes at vacuum levels of 200 and 150 mm Hg with 20-gauge tips.Similarly,proportional changes at vacuum levels of 300 and 250 mm Hg with the 21-gauge tip were nearly equal.The bottle height at which the posterior capsule contacted with the tip and estimated ACP were 57.5±12.6 cm(20.2±7.9 mm Hg)at 200 mm Hg with a 20-gauge tip,35.0±10.0 cm(16.6±6.3 mm Hg)at 150 mm Hg with a 20-gauge tip,47.5±12.6 cm(18.7±8.7 mm Hg)at 300 mm Hg with a 21-gauge tip,and 32.5±5.0 cm(15.7±3.5 mm Hg)at 250 mm Hg with a 21-gauge tip.CONCLUSION:A comprehensive understanding of this chamber system’s characteristics and usage can resolve anterior chamber instability caused by changing preoperative settings on the phaco machine.
文摘On January 11,2025,the 2025 Bejing Roundtable Meeting for International Exhibition Organisations was held in Beijing.The event was co-hosted by the CCPIT Bejing,the Bejing Municipal Commerce Bureau,the Shunyi District People's Government and the Beijing Chamber of International Commerce.
文摘James Joyce’s poetry collection, Chamber Music, which he defines as “chambermade music,” epitomizes his literary pursuit of musicality and resonates with his dual identity as both a lyric poet and an Irishman. Musicality in Chamber Music can first be seen in allusions to musical elements which contribute to the musical revelation of emotions. Furthermore, repetition pervades Chamber Music both in themes and structure, resonating with the cyclical nature of Irish music. Under the influence of the Irish Revival, Joyce creatively navigates the realm of musical lyrics, draws a balance between English and Irish traditions, and provides a seminal model for his further exploration of musical writing in his later masterpieces.
基金Yancheng Science and Technology Bureau(YCBK2023027)。
文摘EMC anechoic chamber is used for radiation emission and radiation immunity test,and the wireless performance of products needs to be tested in OTA anechoic chamber.With more and more electronic and electrical equipment with wireless communication function,the rapid construction of a compatible OTA test system in the existing EMC anechoic chamber can save the cost and space of enterprises and third-party laboratories that already have EMC anechoic chamber.In this paper,the OTA test system is built in the existing EMC anechoic room,the ripple calibration test is carried out according to the OTA standard,the TRP and TIS tests are carried out on two test samples with different wireless communication standards,and the test samples are taken to the OTA anechoic room for a comparison test.The comparison between the ripple calibration data and the OTA test data showed that the EMC anechoic chamber could perform OTA test without affecting the original test ability.The data results provide a basis for the implementation of EMC anechoic chamber compatibility upgrade OTA test,and provide reference for further optimization of the compatible test system,reduction of test differences,and the design of anechoic chamber integrating two test functions.
基金supported by National Natural Science Foundation of China(NSFC)(Nos.12475200 and 12275296)Joint Fund of Research utilizing Large-Scale Scientific Facility of the NSFC and CAS(No.U2032114)Institute of High Energy Physics(Chinese Academy of Sciences)Innovative Project on Sciences and Technologies(Nos.E3545BU210 and E25456U210).
文摘The particle identification(PID)of hadrons plays a crucial role in particle physics experiments,especially in flavor physics and jet tagging.The cluster counting method,which measures the number of primary ionizations in gaseous detectors,is a promising breakthrough in PID.However,developing an effective reconstruction algorithm for cluster counting remains challenging.To address this challenge,we propose a cluster counting algorithm based on long short-term memory and dynamic graph convolutional neural networks for the CEPC drift chamber.Experiments on Monte Carlo simulated samples demonstrate that our machine learning-based algorithm surpasses traditional methods.It improves the K/πseparation of PID by 10%,meeting the PID requirements of CEPC.
文摘Angela Carter’s short story,The Bloody Chamber,was created by rewriting the fairy tale Bluebeard,which expressed her strong feminist views.Based on the theory of spatial criticism,this paper is meant to interpret the growth of the heroine in The Bloody Chamber.It analyzes the nameless bride’s growth process of searching for her true self in the novel from the three levels:social space,physical space and psychological space.
基金National Natural Science Foundation of China,Grant/Award Number:52474080National Key R&D Program of China,Grant/Award Number:2024YFB4007100。
文摘Compressed air energy storage(CAES)has emerged as a grid-scale energy storage linchpin,providing diurnal-to-seasonal timescale energy buffering for renewable power integration.Diverging from conventional salt caverndependent approaches,artificial cavern-based CAES unlocks geographical adaptability through engineered underground containment.This study systematically reviews critical technologies in chamber construction,including site selection,structural design,excavation methods,and post-construction evaluation.Site selection employs a multi-criteria matrix that combines geological and environmental factors.Structural design integrates spatial layout,burial depth,sealing system,and component compatibility to ensure chamber stability.Excavation prioritizes controlled blasting for homogeneous rock,while a tunnel boring machine is deployed in fractured zones to preserve integrity.Postconstruction assessments validate load-bearing capacity,sealing performance,and operational readiness,supported by data-driven maintenance strategies.Ongoing challenges include site-specific geological risks,sealing system durability under cyclic loading,equipment integration,field-scale validation,standardization gaps,and cost-efficiency optimization.These innovations will establish best practices for building large-scale,high-efficiency CAES plants with ultra-long duration and grid resilience,accelerating the transition to carbon-neutral power systems.
基金supported by the Natural Science Foundation of China(No.32171264 and No.81974226)the Sichuan Science and Technology Program(2023NSFSC1609)。
文摘According to the World Health Organization(WHO)manual,sperm concentration should be measured using an improved Neubauer hemocytometer,while sperm motility should be measured by manual assessment.However,in China,thousands of laboratories do not use the improved Neubauer hemocytometer or method;instead,the Makler counting chamber is one of the most widely used chambers.To study sources of error that could impact the measurement of the apparent concentration and motility of sperm using the Makler counting chamber and to verify its accuracy for clinical application,67 semen samples from patients attending the Department of Andrology,West China Second University Hospital,Sichuan University(Chengdu,China)between 13 September 2023 and 27 September 2023,were included.Compared with applying the cover glass immediately,delaying the application of the cover glass for 5 s,10 s,and 30 s resulted in average increases in the sperm concentration of 30.3%,74.1%,and 107.5%,respectively(all P<0.0001)and in the progressive motility(PR)of 17.7%,30.8%,and 39.6%,respectively(all P<0.0001).However,when the semen specimens were fixed with formaldehyde,a delay in the application of the cover glass for 5 s,10 s,and 30 s resulted in an average increase in the sperm concentration of 6.7%,10.8%,and 14.6%,respectively,compared with immediate application of the cover glass.The accumulation of motile sperm due to delays in the application of the cover glass is a significant source of error with the Makler counting chamber and should be avoided.
基金was supported by National Key R&D Program of China(No.2022YFE0103900)the National Natural Science Foundation of China(Nos.11875301,11875302,U1867214,U1832105,U2032166 and U1832167)+2 种基金the Fundamental Research Funds for the Central Universities(No.lzujbky-2022-sp06)the CAS“Light of West China”Programthe Heavy Ion Research Facility in Lanzhou。
文摘The semicylindrical time projection chamber(scTPC)is designed to measure the angular distribution of the cross section for intermediate-energy(3He,t)charge-exchange reactions in inverse kinematics.The scTPC prototype comprises a cathode,field cage,drift region,amplification structure based on a multilayer thick gas electron multiplier(THGEM),and a readout plane with 886 zigzag-shaped pads.The gain uniformity of the THGEM and the drift velocity of electrons were calibrated.Track recognition based on the Hough transform was then developed to reconstruct cosmic ray tracks and determine their position resolution.The position resolution of secondary particle tracks resulting from collisions between the heavy-ion beam and the 3He target was measured,yielding an x-resolution of 0.71 mm and a z-resolution of 0.73 mm.The scTPC demonstrates sufficient energy and spatial resolution to support charge-exchange reaction experiments in inverse kinematics.
基金Supported by National Natural Science Foundation of China(No.82201171,No.82171050,No.82471072).
文摘AIM:To describe the alterations of the vitreous pathology and anterior chamber(AC)angle structures following transscleral cyclophotocoagulation(TSCP)and better understand the mechanism of post-laser intraocular pressure(IOP)reduction in angle-closure glaucoma(ACG).METHODS:Porcine eyes ex vivo and rabbit eyes in vivo were used.In porcine eyes,permeability rates of the anterior vitreous cortex(AVC)and anterior hyaloid membrane(AHM)were assessed using Schirmer’s strips.Permeability rates in the circumlental space were compared with or without TSCP bursts.Fluorescein diffusion times from the vitreous to the AC were compared between eyes with and without TSCP.In rabbit eyes,changes in IOP and AC angle structures under ultrasound biomicroscopy(UBM)were evaluated at intervals of 30min,7d,and 14d after TSCP.Vitreous pathology was examined using scanning electron microscopy(SEM)immediately and 14d after TSCP.RESULTS:In porcine eyes(n=20),the median(range)permeability rates were 10.3(range 9.8–10.8)mm/min for the AVC and 4.3(range 3.9–4.9)mm/min for the AHM(P=0.009).Permeability rates in the circumlental space were 4.2(range 3.8–4.9)mm/min in areas without TSCP,6.2(range 5.7–6.8)mm/min in areas with non-burst TSCP,and 11.3(range 10.9–11.8)mm/min in areas with burst TSCP(P=0.002).The median(range)fluorescein diffusion time was 5(range 3–8)min in eyes undergoing TSCP,whereas it was 40min(range 35–68)in eyes without TSCP(P<0.001).In rabbit eyes(n=20),SEM showed immediate localized damage to the AHM,AVC,and posterior lens zonules in areas subjected to TSCP bursts,and obvious lens zonule loss with cellular infiltration and possible vitreous liquefaction by post-op day 14.Persistent widening of AC angles was noted at postoperative days 7 and 14,although a significant reduction in IOP was only observed at postoperative day 7.CONCLUSION:TSCP-induced damage on the zonules,AHM,and AVC potentially enhances fluid outflow from the vitreous,leading to a widened AC angle and vitreous liquefaction in rabbits.These observations offer insights into mechanisms of TSCP in lowering IOP and pathogenic roles of vitreous in ACG.
基金supported by the National Natural Science Foundation of China(Nos.11927901,11875301,11875302,U1867214,U1832105,U1832167)the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB34000000)+2 种基金the National Key R&D Program of China(No.2018YFE0205200)the CAS"Light of West China"Programthe Tsinghua University Initiative Scientific Research Program。
文摘A half-size prototype of the multi wire drift chamber for the cooling storage ring external-target experiment(CEE)was assembled and tested in the 350 MeV/u Kr+Fe reactions at the heavy-ion research facility in Lanzhou.The prototype consists of six sense layers,where the sense wires are stretched in three directions X,U,and V;meeting 0?,30?,and-30?,respectively,with respect to the vertical axis.The sensitive area of the prototype is 76 cm×76 cm.The amplified and shaped signals from the anode wires were digitized in a serial capacity array.When operating at a high voltage of 1500 V on the anode wires,the efficiency for each layer is greater than 95%.The tracking residual is approximately 301±2μm.This performance satisfies the requirements of CEE.
文摘AIM:To assess whether the implantation of a posterior chamber phakic intraocular lens produces changes in optical coherence tomography(OCT)measurements of macular thickness(MT)and two parameters that define the structure of the optic nerve,the peripapillary nerve fiber layer(RNFL)and the Bruch’s membrane opening-minimum rim width(BMO-MRW).METHODS:This nonrandomized prospective pre-post study included 86 eyes of 48 patients(age,20-47y;axial length:23.10-28.95 mm)scheduled for myopia or myopic astigmatism correction with implantation of the implantable collamer lens(ICL).Eyes with glaucoma or any other ocular disease that could alter OCT results were excluded.RNFL,BMO-MRW and MT were measured preoperatively,and at 1 and 6mo after surgery using spectral-domain OCT.Changes between preoperative and postoperative values were evaluated.RESULTS:There was a significant increase in BMOMRW at 1mo(mean change:3.48±15.07μm,P=0.041).No significant changes were found during the rest of followup(1-6mo postop.,P=0.623).There was also a significant increase in RNFL thickness at 1mo af ter surger y(1.45±2.18μm,P<0.001),but with a significant reduction from 1 to 6mo postoperatively(P=0.002).Regarding MT,it increased significantly at 1mo(2.46±3.76μm,P<0.001),with a significant decrease afterwards(P=0.048).Measurements of the three parameters at 6mo were slightly superior to preoperative values(P<0.01).CONCLUSION:Minimal changes are induced in BMOMRW,RNFL and MT after ICL implantation in healthy eyes,confirming the safety of the surgical procedure regarding the structure of the optic nerve head and the macula,and indicating that this phakic intraocular lens seems to have a slight impact on OCT measurements.
