Theoretically,copper–niobium(Cu-Nb)composite superconducting cavities have excellent potential for high thermal and mechanical stability.They can appropriately exploit the high-gradient surface processing recipes dev...Theoretically,copper–niobium(Cu-Nb)composite superconducting cavities have excellent potential for high thermal and mechanical stability.They can appropriately exploit the high-gradient surface processing recipes developed for the bulk niobium(Nb)cavity and the thick copper(Cu)layer’s high thermal conductivity and rigidity,thereby enhancing the operational stability of the bulk Nb cavities.This study conducted a global review of the technical approaches employed for fabricating Cu-Nb composite superconducting cavities.We explored Cu-Nb composite superconducting cavities based on two technologies at the Institute of Modern Physics,Chinese Academy of Sciences(IMP,CAS),including their manufacturing processes,radio-frequency(RF)characteristics,and mechanical performance.These cavities exhibit robust mechanical stability.First,the investigation of several 1.3 GHz single-cell elliptical cavities using the Cu-Nb composite sheets indicated that the wavy structure at the Cu-Nb interface influenced the reliable welding of the Cu-Nb composite parts.We observed the generation and trapping of magnetic flux density during the T_c crossing of Nb in cooldown process.The cooling rates during the T_c crossing of Nb exerted a substantial impact on the performance of the cavities.Furthermore,we measured and analyzed the surface resistance R_(s)attributed to the trapped magnetic flux induced by the Seebeck effect after quenching events.Second,for the first time,a low-beta bulk Nb cavity was plated with Cu on its outer surface using electroplating technology.We achieved a high peak electric field E_(pk)of~88.8 MV/m at 2 K and the unloaded quality factor Q_(0)at the E_(pk)of 88.8 MV/m exceeded 1×10^(10).This demonstrated that the electroplating Cu on the bulk Nb cavity is a practical method of developing the Cu-Nb composite superconducting cavity with superior thermal stability.The results presented here provide valuable insights for applying Cu-Nb composite superconducting cavities in superconducting accelerators with stringent operational stability requirements.展开更多
BACKGROUND Preoperative distinguishing between benign and malignant gastrointestinal stromal tumors(GISTs)poses a challenge.Ultrasound elastography has emerged as a promising diagnostic tool;however,further investigat...BACKGROUND Preoperative distinguishing between benign and malignant gastrointestinal stromal tumors(GISTs)poses a challenge.Ultrasound elastography has emerged as a promising diagnostic tool;however,further investigation is needed to assess its diagnostic accuracy in evaluating GISTs.AIM To evaluate the accuracy of ultrasound elastography for differentiating between benign and malignant GISTs.METHODS This prospective study included 110 patients with 103 histopathologically confirmed GISTs between January 2021 and December 2023.All tumors underwent conventional ultrasound examination,strain elastography(SE),and shearwave elastography(SWE)before surgical resection.The study evaluated elastographic parameters such as strain ratio,elastographic patterns,mean elastic modulus,and heterogeneity index.Diagnostic performance was evaluated using receiver operating characteristic curve analysis,with histopathological diagnosis as the reference standard.RESULTS Of the 103 GISTs,45(43.7%)were benign and 58(56.3%)were malignant based on modified National Institutes of Health criteria.Malignant GISTs exhibited significantly higher strain ratios(4.82±1.73 vs 2.31±0.89;P<0.001)and mean elastic modulus values(45.6±15.8 kPa vs 21.3±8.4 kPa;P<0.001)than benign tumors.The optimal cutoff values were 3.45 for the strain ratio(sensitivity:84.5%,specificity:86.7%)and 32.5 kPa for the mean elastic modulus(sensitivity:87.9%,specificity:88.9%).The areas under the curve were 0.892 and 0.918,respectively.Interobserver agreement was excellent for both SE[intraclass correlation coefficient(ICC)=0.88]and SWE(ICC range:0.85-0.93)measurements.CONCLUSION Ultrasound elastography shows high diagnostic accuracy in distinguishing between benign and malignant GISTs.Combining SE and SWE provides complementary parameters for preoperative risk stratification.展开更多
Since the new curriculum reform,labor education has gradually shed its marginalized position in the“five educations,”and the labor curriculum has become an independent course officially separated from comprehensive ...Since the new curriculum reform,labor education has gradually shed its marginalized position in the“five educations,”and the labor curriculum has become an independent course officially separated from comprehensive practical activity courses.Exploring the practical path of labor curriculum in compulsory education in China has become the primary task of labor education in China.Based on the practical situation of labor curriculum in compulsory education in China,drawing on the theory of overlapping influence domains,and from the perspective of collaborative education among family,school,and community,this paper proposes a curriculum practical path of“school-led”family-school-community collaboration and a curriculum practical path guided by“student-centered”sentiment,in order to provide references for the practice of labor curriculum in compulsory education in China.展开更多
对双主动全桥DAB(dual active bridge)双向DC/DC变换器的调制方案进行了研究,DAB变换器的主要优势在于具有对称结构、双向潮流能力、宽软开关区域和灵活的控制能力等特点。控制这种拓扑结构最简单的方法是通过控制变换器原副边全桥之间...对双主动全桥DAB(dual active bridge)双向DC/DC变换器的调制方案进行了研究,DAB变换器的主要优势在于具有对称结构、双向潮流能力、宽软开关区域和灵活的控制能力等特点。控制这种拓扑结构最简单的方法是通过控制变换器原副边全桥之间的移相角来控制功率传输的方向和大小。然而在轻载条件下,当变换器的输入或输出电压变化较大时,会产生大量的无功功率,同时部分开关管的零电压开关ZVS(zero voltage switching)操作会丢失而直接导致转换效率变低。因此,为了提高DAB变换器的效率,提出了一种混合单移相调制PSM(phase shift modulation)方案,在保持控制简单的基础上,通过减小电感电流有效值,扩大软开关的范围,提高了变换器的效率。首先,通过让拓展移相EPS(extended phase shift)、双移相DPS(dual phase shift)以及三移相TPS(triple phase shift)调制方案中的可控变量相等,从而形成了4种不同的PSM方案。接着,对这些调制方案进行了稳态特征的比较分析,包括传输功率容量、电感电流水平以及软开关性能等。在此基础上,提出了一种混合PSM方案。最后,通过搭建实验平台验证了所提出调制方案的有效性和正确性。展开更多
This study explores the application value of Zhao Shi Lei-huo-jiu in managing common postoperative gastrointestinal symptom clusters following rectal cancer surgery,under the framework of the Enhanced Recovery After S...This study explores the application value of Zhao Shi Lei-huo-jiu in managing common postoperative gastrointestinal symptom clusters following rectal cancer surgery,under the framework of the Enhanced Recovery After Surgery(ERAS)concept.By detailing the development,core elements,and application of ERAS in colorectal surgery,combined with the historical origins,unique techniques,and mechanisms of Zhao Shi Lei-huo-jiu,this paper highlights the innovation of integrating traditional Chinese medicine treatments with modern surgical recovery principles.Through a rigorously designed research process,rectal cancer postoperative patients were selected as research subjects,and the data collection and implementation steps were explicitly outlined.The study results provide scientific evidence for the practical efficacy and advantages of Zhao Shi Lei-huo-jiu in postoperative rehabilitation for rectal cancer,offering significant practical implications for guiding clinical practice and promoting early patient recovery.展开更多
基金supported by the Large Research Infrastructures China initiative Accelerator Driven System(No.2017-000052-75-01-000590)the Youth Innovation Promotion Association of Chinese Academy of Sciences(No.2022422)+1 种基金the Young Scientists of National Natural Science Foundation of China(No.12005275)the Advanced Energy Science and Technology Guangdong Laboratory(No.HND22PTZZYY)。
文摘Theoretically,copper–niobium(Cu-Nb)composite superconducting cavities have excellent potential for high thermal and mechanical stability.They can appropriately exploit the high-gradient surface processing recipes developed for the bulk niobium(Nb)cavity and the thick copper(Cu)layer’s high thermal conductivity and rigidity,thereby enhancing the operational stability of the bulk Nb cavities.This study conducted a global review of the technical approaches employed for fabricating Cu-Nb composite superconducting cavities.We explored Cu-Nb composite superconducting cavities based on two technologies at the Institute of Modern Physics,Chinese Academy of Sciences(IMP,CAS),including their manufacturing processes,radio-frequency(RF)characteristics,and mechanical performance.These cavities exhibit robust mechanical stability.First,the investigation of several 1.3 GHz single-cell elliptical cavities using the Cu-Nb composite sheets indicated that the wavy structure at the Cu-Nb interface influenced the reliable welding of the Cu-Nb composite parts.We observed the generation and trapping of magnetic flux density during the T_c crossing of Nb in cooldown process.The cooling rates during the T_c crossing of Nb exerted a substantial impact on the performance of the cavities.Furthermore,we measured and analyzed the surface resistance R_(s)attributed to the trapped magnetic flux induced by the Seebeck effect after quenching events.Second,for the first time,a low-beta bulk Nb cavity was plated with Cu on its outer surface using electroplating technology.We achieved a high peak electric field E_(pk)of~88.8 MV/m at 2 K and the unloaded quality factor Q_(0)at the E_(pk)of 88.8 MV/m exceeded 1×10^(10).This demonstrated that the electroplating Cu on the bulk Nb cavity is a practical method of developing the Cu-Nb composite superconducting cavity with superior thermal stability.The results presented here provide valuable insights for applying Cu-Nb composite superconducting cavities in superconducting accelerators with stringent operational stability requirements.
文摘BACKGROUND Preoperative distinguishing between benign and malignant gastrointestinal stromal tumors(GISTs)poses a challenge.Ultrasound elastography has emerged as a promising diagnostic tool;however,further investigation is needed to assess its diagnostic accuracy in evaluating GISTs.AIM To evaluate the accuracy of ultrasound elastography for differentiating between benign and malignant GISTs.METHODS This prospective study included 110 patients with 103 histopathologically confirmed GISTs between January 2021 and December 2023.All tumors underwent conventional ultrasound examination,strain elastography(SE),and shearwave elastography(SWE)before surgical resection.The study evaluated elastographic parameters such as strain ratio,elastographic patterns,mean elastic modulus,and heterogeneity index.Diagnostic performance was evaluated using receiver operating characteristic curve analysis,with histopathological diagnosis as the reference standard.RESULTS Of the 103 GISTs,45(43.7%)were benign and 58(56.3%)were malignant based on modified National Institutes of Health criteria.Malignant GISTs exhibited significantly higher strain ratios(4.82±1.73 vs 2.31±0.89;P<0.001)and mean elastic modulus values(45.6±15.8 kPa vs 21.3±8.4 kPa;P<0.001)than benign tumors.The optimal cutoff values were 3.45 for the strain ratio(sensitivity:84.5%,specificity:86.7%)and 32.5 kPa for the mean elastic modulus(sensitivity:87.9%,specificity:88.9%).The areas under the curve were 0.892 and 0.918,respectively.Interobserver agreement was excellent for both SE[intraclass correlation coefficient(ICC)=0.88]and SWE(ICC range:0.85-0.93)measurements.CONCLUSION Ultrasound elastography shows high diagnostic accuracy in distinguishing between benign and malignant GISTs.Combining SE and SWE provides complementary parameters for preoperative risk stratification.
文摘Since the new curriculum reform,labor education has gradually shed its marginalized position in the“five educations,”and the labor curriculum has become an independent course officially separated from comprehensive practical activity courses.Exploring the practical path of labor curriculum in compulsory education in China has become the primary task of labor education in China.Based on the practical situation of labor curriculum in compulsory education in China,drawing on the theory of overlapping influence domains,and from the perspective of collaborative education among family,school,and community,this paper proposes a curriculum practical path of“school-led”family-school-community collaboration and a curriculum practical path guided by“student-centered”sentiment,in order to provide references for the practice of labor curriculum in compulsory education in China.
文摘This study explores the application value of Zhao Shi Lei-huo-jiu in managing common postoperative gastrointestinal symptom clusters following rectal cancer surgery,under the framework of the Enhanced Recovery After Surgery(ERAS)concept.By detailing the development,core elements,and application of ERAS in colorectal surgery,combined with the historical origins,unique techniques,and mechanisms of Zhao Shi Lei-huo-jiu,this paper highlights the innovation of integrating traditional Chinese medicine treatments with modern surgical recovery principles.Through a rigorously designed research process,rectal cancer postoperative patients were selected as research subjects,and the data collection and implementation steps were explicitly outlined.The study results provide scientific evidence for the practical efficacy and advantages of Zhao Shi Lei-huo-jiu in postoperative rehabilitation for rectal cancer,offering significant practical implications for guiding clinical practice and promoting early patient recovery.
