检索结果-南通市图书馆

在线全文

学校读者我要写书评

暂无评论

儿童咯咯笑尿失禁的诊治进展

中华儿科杂志 2024年第6期62卷 580-582页

作者：吴雨涵马骏上海交通大学医学院附属上海儿童医学中心发育行为儿科上海200127

儿童咯咯笑尿失禁是日间尿失禁的一种,由于发病率低,临床上对其认识不足,容易与其他日间尿失禁亚型混淆导致误诊,故明确诊断十分关键。目前咯咯笑尿失禁主流治疗方案为标准泌尿疗法及生物反馈,药物哌甲酯可作为二线治疗。

关键词：尿失禁哌甲酯生物反馈二线治疗儿童明确诊断泌尿诊治进展

IGBT电力电子系统小时间尺度动态性能分析与计算的电磁场-电路耦合模型

在线全文

学校读者我要写书评

暂无评论

电工技术学报 2017年第13期32卷 14-22页

作者：马瑜涵陈佳佳胡斯登杨仕友浙江大学电气工程学院杭州310027

为了解决现有模型不完全适用于小时间尺度电力电子系统瞬态性能分析与计算的不足,建立用于IGBT电力电子系统小时间尺度动态特性分析、计算的三维电磁场-电路耦合计算模型,并提出其求解的迭代计算方法。为精确描述小时间尺度下IGBT内部... 详细信息

为了解决现有模型不完全适用于小时间尺度电力电子系统瞬态性能分析与计算的不足,建立用于IGBT电力电子系统小时间尺度动态特性分析、计算的三维电磁场-电路耦合计算模型,并提出其求解的迭代计算方法。为精确描述小时间尺度下IGBT内部瞬态电磁场及其分布规律,建立的IGBT本体三维有限元模型考虑位移电流、趋肤效应和引线邻近效应等复杂因素的影响;为考虑极小时间尺度下线路中杂散参数的电磁效应,高阶杂散参数电路模型采用多段等效电路模拟杂散参数的影响,同时采用谐态电磁场数值分析计算方法提取模型参数以考虑趋肤效应等的影响。基于IGBT内部电磁暂态过程的分析,提出一种改进的IGBT电路模型;为兼顾计算精度和计算时间的要求,提出等效高阶电路模型的一种降阶方法。仿真计算和实验测试结果证明了所建模型及求解方法的有效性和正确性。

关键词：绝缘栅双极型晶体管杂散参数有限元方法降阶技术位移电流

基于长间隙放电试验适用于大尺寸输电线路的改进电气几何模型

在线全文

学校读者我要写书评

暂无评论

中国电机工程学报 2017年第12期37卷 3654-3661页

作者：王羽邓冶强文习山马宇晗蓝磊安韵竹鄂盛龙武汉大学电气工程学院湖北省武汉市430072 山东理工大学电气与电子工程学院山东省淄博市255000 广东电力科学研究院广东省广州市510080

电气几何模型(electric geometry model,EGM)作为解决雷电屏蔽问题的工程模型,广泛应用于计算评估高压、超高压输电线路的雷电绕击性能。然而,随着特高压输电线路杆塔高度的提高和空气间隙的增长,运用现有EGM得到的绕击率和实际观测数... 详细信息

电气几何模型(electric geometry model,EGM)作为解决雷电屏蔽问题的工程模型,广泛应用于计算评估高压、超高压输电线路的雷电绕击性能。然而,随着特高压输电线路杆塔高度的提高和空气间隙的增长,运用现有EGM得到的绕击率和实际观测数据有较大出入。鉴于此,该文基于1~10m的棒-棒长空气间隙负极性20/2500μs操作冲击50%放电电压试验数据,并引入Idone的雷电通道回击速度概率分布,修正了现有击距公式;再根据棒-棒间隙和棒-板间隙的50%放电电压在4m处发生翻转的特点,结合试验结果修正了大地的击距系数,提出了一种适用于大尺寸输电线路的改进EGM。最后运用该文提出的改进EGM分别对日本500、1000和中国1000k V交流输电线路的绕击率进行计算,与日本长期的雷击观测数据对比表明:该文提出的改进EGM较现有EGM更加适合大尺寸输电线路,尤其是各相导线绕击比例和观测数据更加吻合。该文提出的改进EGM能为大尺寸输电线路雷电屏蔽设计提供参考。

关键词：特高压输电线路绕击率电气几何模型击距负极性长间隙冲击放电

Uniform decomposition of velocity gradient tensor

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2024年第1期36卷 24-34页

作者： Chenxi ma Chaoqun Liu Department of mathematics University of Texas at ArlingtonArlingtonTXUSA

In this paper,the principal decomposition of the velocity gradient tensor[∇v]is discussed in 3 cases based on the discriminant∆:∆0 with 3 distinct real eigen values,and∆=0 with 1 or 2 distinct real eigen *** velocity gradient tensor can also be classified as rotation point,which can be decomposed into three parts,i.e.,rotation[R],shear[S]and stretching/compression[SC],and non-rotation point,we defined a new resistance term[L],and the tensor can be decomposed into three parts,i.e.,resistance[L],shear[S]and stretching/compression[SC].Example matric are also displayed to demonstrate the new *** of principal decomposition between 3 different cases,and between Resistance and Liutex will also be discussed.

关键词： Velocity gradient Liutex resistance fluid kinematics

VOC emitted by biopharmaceutical industries:Source profiles,health risks,and secondary pollution

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2024年第1期135卷 570-584页

作者： Jiawei ma Lin Li State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China University of Chinese Academy of Sciences Beijing 100049China National Engineering Laboratory for VOCs Pollution Control material&Technology University of Chinese Academy of SciencesBeijing 101408China

The biopharmaceutical industry contributes substantially to volatile organic compounds(VOCs)emissions,causing growing concerns and social developmental *** study conducted an on-site investigation of the process-based emission of VOCs from three biopharmaceutical *** the workshops of the three enterprises,26 VOCs were detected,which could be sorted into 4 classes:hydrocarbons,aromatic hydrocarbons,oxygen-containing compounds,and nitrogen-containing *** were the main components of waste gases,accounting for 44.13%-77.85%of the overall ***-based source profiles were compiled for each process unit,with the fermentation and extraction units of tiamulin fumarate being the main source of VOC *** heptanone,vinyl acetate,diethylamine,propylene glycol methyl ether(PGME),and benzene were screened as priority pollutants through a fuzzy comprehensive evaluation *** level concentration simulation results of the Gauss plume diffusion model demonstrated that the diffusivity of VOCs in the atmosphere was relatively high,indicating potential non-carcinogenic and carcinogenic risks 1.5-2 km ***,the process-based formation potentials of ozone and secondary organic aerosols(SOAs)were determined and indicated that N-methyl-2-pyrrolidone,dimethyl heptanone,and PGME should be preferentially controlled to reduce the ozone formation potential,whereas the control of benzene and chlorobenzene should be prioritized to reduce the generation of *** results provide a basis for understanding the characteristics of VOC emission by biopharmaceutical industries and their diffusion,potentially allowing the development of measures to reduce health risks and secondary pollution.

关键词： Biopharmaceutical Volatile organic compound Priority pollutant Exposure risk Secondary pollution

Deterministic and Robust Volt-var Control Methods of Power System Based on Convex Deep Learning

在线全文

学校读者我要写书评

暂无评论

Journal of Modern Power Systems and Clean Energy 2024年第3期12卷 719-729页

作者： Qing ma Changhong Deng the School of Electrical Engineering and Automation Wuhan UniversityWuhanChina

Volt-var control(VVC)is essentially a non-convex optimization problem due to the non-convexity of power flow(PF)constraints,resulting in the difficulty in obtaining the optimum without convexity *** existing second-order cone method for the convexity conversion often leads to a sharp increase in PF constraints and optimization variables,which in turn increases the optimization difficulty or even leads to optimization *** paper first proposes a deterministic VVC method based on convex deep learning power flow(DLPF).This method uses the input convex neural network(ICNN)to establish a single convex mapping between state parameters and node voltage to complete the convexity conversion while the optimization variables only correspond to reactive power equipment,which can ensure the global optimum with extremely fast computation *** cope with the impact brought by the uncertainty of distributed energy and omit the additional worst scenario search of traditional robust VVC,this paper proposes robust VVC method based on convex deep learning interval power flow(DLIPF),which continues to adopt ICNN to establish another convex mapping between state parameters and node voltage *** DLIPF with DLPF,this method decreases the modeling and optimization difficulty of robust VVC *** results on 30-bus,118-bus,and 200-bus systems prove the correctness and rapidity of the proposed methods.

关键词： Volt-var control convexity conversion convex deep learning power flow

Copper slag assisted coke reduction of phosphogypsum for sulphur dioxide preparation

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2024年第1期65卷 43-53页

作者： Dong ma Qinhui Wang State Key Laboratory of Clean Energy Utilization Institute for Thermal Power EngineeringZhejiang UniversityHangzhou 310027China

The reduction of phosphogypsum(PG)to lime slag and SO_(2)using coke can effectively alleviate the environmental problems caused by ***,the PG decomposition temperature remains high and the product yield remains *** adding additives,the decomposition temperature can be further reduced and PG decomposition rate and product yield can be ***,the use of current additives such as Fe_(2)O_(3)and SiO_(2)brings the problem of increasing economic ***,it is proposed to use solid waste copper slag(CS)as a new additive to reduce PG to prepare SO2,which can reduce the cost and meet the environmental benefits at the same *** effects of proportion,temperature and thermostatic time on PG decomposition are investigated by experimental and kinetic analysis combined with FactSage thermodynamic calculations to optimize the roasting ***,the reaction mechanism is *** is found that adding CS to the coke and PG system can increase the rate of PG decomposition and SO_(2)yield while lowering the PG decomposition *** example,when the CS/PG mass ratio increases from 0 to 1,PG decomposition rate increases from 83.38%to 99.35%,SO_(2)yield increases from 78.62%to 96.81%,and PG decomposition temperature decreases from 992.4℃to 949.6℃.The optimal reaction parameters are CS/PG mass ratio of 1,Coke/PG mass ratio of 0.06 at 1100℃for 20 min with 99.35%PG decomposition rate and 96.81%SO_(2) *** process proceeds according to the following reactions:2CaSO_(4)+ 0.7C + 0.8Fe_(2)SiO_(4)→0.8Ca_(2)SiO_(4)+ 0.2Ca_(2)Fe_(2)O_(5)+ 0.4Fe_(3)O_(4)+2SO_(2)+ 0.7CO_(2)Finally,a process for decomposing PG with coke and CS is proposed.

关键词： Phosphogypsum Sulfur dioxide Copper slag Fluidized-bed Reduction Waste treatment

On the Security of Homomorphic Encryption Schemes with Restricted Decryption Oracles

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2024年第5期37卷 2240-2261页

作者： ma Guangsheng LI Hongbo School of mathematics and Physics North China Electric Power UniversityBeijing 100096China Academy of mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Fully homomorphic encryption(FHE)can be used for privacy-preserving aggregation of medical *** this typical application,the security against passive attacks has been well studied by Li and Micciancio(2021).In this paper,the authors further consider a“nearly passive”kind of attack,where the attacker may behave like a passive attacker in the view of the third-party *** capture the security against this hard-to-detect attack,the authors propose a new notion of IND-CPA^(rD)*** authors show that the standard LWE encryption and its related FHE schemes can not defend against IND-CPA^(rD)attack,even under a stricter rule limiting the content and number of queries made by the *** make the application of FHE schemes more secure,the authors discuss some possible modifications that may serve as countermeasures to IND-CPA^(rD)attack.

关键词： Homomorphic encryption privacy secure cloud computing security

A review of recent advances in the effects of surface and interface properties on marine propellers

在线全文

学校读者我要写书评

暂无评论

Friction 2024年第2期12卷 185-214页

作者： manfu ZHU Liran ma State Key Laboratory of Tribology in Advanced Equipment Tsinghua UniversityBeijing 100084China

marine propellers are important propulsion devices for both surface ships and underwater *** severe environmental problems have required further performance enhancement for ***,traditional methods to improve propeller performances through geometrical and structural optimizations have been extensively investigated,while the underlying mechanisms of the effects of surface and interface properties on marine propellers are still far from being fully *** paper presented a comprehensive review of recent advances in the effects of surface and interface properties,such as surface roughness and surface wettability,on marine propellers with an emphasis on the significant improvements in both hydrodynamic and cavitation performances,hoping to arouse more in-depth investigations in the field of surface/interface science and technologies on marine propellers,and also promote the state-of-the-art technologies,such as superlubricity technology,into practical applications.

关键词： marine propellers hydrodynamics cavitation surface roughness surface wettability