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机械与机械化:近代中国农业现代化的共识及忧虑

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社会科学战线 2024年第5期 124-139页

作者：李金铮南开大学历史学院天津300192

近代以降,在清末洋务运动至南京国民政府结束的80年间,中国各界尤其是知识界一直没有停止对农业机械的讨论,成为中国农业现代化道路探索进程的重要组成部分。其中,最为强烈的追求和共识是与传统农具决裂,使用农业机械乃至实现机械化,具... 详细信息

近代以降,在清末洋务运动至南京国民政府结束的80年间,中国各界尤其是知识界一直没有停止对农业机械的讨论,成为中国农业现代化道路探索进程的重要组成部分。其中,最为强烈的追求和共识是与传统农具决裂,使用农业机械乃至实现机械化,具体则经历了从直觉到自觉再到科学化论证的演变。在推广农业机械的设想及实践上,又有一个从简单地向西方购买,到仿造、制造,以及重视调查研究、增强自主性的过程。对合作社与农业机械的关系、大农场与农业机械之间的关系,讨论和认识尤为丰富。然而,理想与实践之间的差距是巨大的,农业机械推广的成就非常有限,传统农具依旧占有统治地位。正因为此,也出现了质疑乃至反对推广农业机械的声音,这些分歧多是对传统与现代、对未来必然趋势和当下社会经济环境制约乃至改良与革命的不同认识的反映。

关键词：农业机械农业现代化大农场合作社

中共抗日根据地的简体字——以一份手写油印本为基础的量化分析

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抗日战争研究 2024年第1期 13-26,M0003页

作者：李金铮南开大学历史学院暨中国社会史研究中心

简体字的使用并非始于中国共产党,而是自汉字产生以来一直就有的演化趋势,甚至南京国民政府也颁布过简体字表。只是国民政府并没有实际推行,而中国共产党在革命时期即有使用简体字的实践。不过从中共抗日根据地来看,对简体字并无统一的... 详细信息

简体字的使用并非始于中国共产党,而是自汉字产生以来一直就有的演化趋势,甚至南京国民政府也颁布过简体字表。只是国民政府并没有实际推行,而中国共产党在革命时期即有使用简体字的实践。不过从中共抗日根据地来看,对简体字并无统一的态度和政策,有的根据地时而肯定、时而否定,有的坚决反对使用,反映了简体字使用过程中的矛盾和张力。以一份手写油印稿《考察晋察冀边区统一累进税报告》为例进行统计,在3.5万余字中,使用简体字190个。其中有84个字渊源甚早,在先秦至明清时期就陆续出现了。与国民政府颁布的简体字表324个字比较,有87个相同,73个为新增。与根据地文字学家罗竹风统计的300余个简体字比较,有86个相同,54个为新增。根据地简体字的使用,为新中国成立后的简体字改革提供了经验。

关键词：汉字简体字抗日战争根据地中共革命

Analysis and control of inter-electrode gap during leveling process in counter-rotating electrochemical machining

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Chinese Journal of Aeronautics 2019年第11期32卷 2557-2565页

作者： Dengyong WANG jinzheng li Bin HE Di ZHU College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technology Nanjing 210016China

The inter-electrode gap(IEG) is an essential parameter for the anode shaping process in electrochemical machining(ECM) and directly affects the machining accuracy. In this paper, the IEG during the leveling process of an oval anode workpiece in counter-rotating ECM(CRECM)is investigated. The variation of the minimum IEG is analyzed theoretically, and the results indicate that rather than reaching equilibrium, the minimum IEG in CRECM expands constantly when a constant feed speed is used for the cathode tool. This IEG expansion leads to a poor localization effect and has an adverse influence on the roundness of the machined workpiece. To maintain a small constant IEG in CRECM, a variable feed speed is used for the cathode based on a fitted equation. The theoretical results show that the minimum IEG can be controlled at a small value by using an accelerated feed speed. Experiments have been conducted using a specific experimental apparatus in which the cathode tool is designed as a combined structure of two sectors and a thin sheet. By detecting the machining currents flowing through the minimum IEG, how the latter varies is obtained indirectly. The results indicate that using an accelerated feed speed is effective for controlling the IEG, thereby improving the roundness of the machined workpiece.

关键词： Counter-rotating Electrochemical machining Inter-electrode gap Leveling process Variable feed speed

Therapeutic potential of stem cell in liver regeneration

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Frontiers of Medicine 2011年第1期5卷 26-32页

作者： jinzheng li Min li Bolin NIU Jianping GONG Chongqing Key Laboratory of Hepatobiliary Surgery and Department of Hepatobiliary Surgery Second Affiliated HospitalChongqing Medical UniversityChongqing 400010China

liver transplantation is the only life-saving procedure for patients with end-stage liver disease.However,its potential benefits are hampered by many disadvantages,such as the relative shortage of donors,operative risks,and high costs.These issues have prompted the search for new alternative therapies for irreversible liver disease.Stem cell therapy,with the ability for self-renewal and potential for multilineage differentiation,is a promising alternative approach.Several studies have demonstrated that transplantation of hepatic stem/progenitor cells or hepatocyte-like cells derived from multipotent stem cells leads to donor cell-mediated repopulation of the liver and improved survival rates in experimental models of liver disease.However,a registered clinical application based on stem cell technology will take at least an additional 5 to 10 years because of some limitations;e.***.the lack of suitable cell sources and risk of teratoma formation.This review summarizes the general understanding of the therapeutic potentials of stem cells in liver disease,including the sources,mechanisms,and delivery methods of hepatic stem cells in liver regeneration,and discusses some challenges for their therapeutic application.

关键词： stem cell liver disease regenerative medicine

Hypoxia regulates reactive oxygen species levels in SHG-44 glioma cells

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Neural Regeneration Research 2013年第6期8卷 554-560页

作者： Haitao Jiang Jiangtao Xie Gaofeng Xu Yongyong Su jinzheng li Mang Zhu Maode Wang First Affiliated Hospital Xi'an Jiaotong University Xianyang Central Hospital Xi'an Central Hospital

In the present study, cultured human SHG-44 glioma cells were subjected to a hypoxic environment simulated using the CoOl2 method. Flow cytometry showed increased reactive oxygen species production in these cells. Real-time reverse transcription-PCR showed significantly increased hypoxia-inducible factor-la mRNA expression in cells exposed to the hypoxic condition. The antioxidant N-acetylcysteine significantly inhibited reactive oxygen species production and reduced hypoxia-inducible factor-la mRNA expression in normoxic and hypoxic groups, especially in the latter group. These findings indicate that hypoxia induces reactive oxygen species production and hypoxia-inducible factor-la mRNA expression in human SHG-44 glioma cells, and that the antioxidant N-acetylcysteine can inhibit these changes.

关键词： neural regeneration basic research central nervous system reactive oxygen species hypoxia-inducible factor-l a hypoxia N-acetylcysteine glioma antioxidant photographs-containingpaper neuroregeneraion

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肝胆外科理论课程中线上教学的应用

继续医学教育 2024年第4期38卷 101-104页

作者：何堃李金政重庆医科大学附属第二医院肝胆外科重庆400010

目的探讨新型BOPPPS(bridge-in、objective、pre-assessment、participatory-learning、post-assessment、summary)教学模式在肝胆外科线上教学中的应用价值。方法选取2022年3-7月重庆医科大学2019级临床医学二系本科生(205名)及2018级临床医学二系本科生(200名)为研究对象,2019级学生为线上教学,为研究组,2018级学生为线下教学,为对照组。教研室师资创新性地将BOPPPS教学模式拆分融入线上教学课程3个阶段的设计中,并对课前、课中、课后3个阶段的教学进行细分、优化,提出了“分组讨论”的参与式教学方法,加强了师生互动。通过直播软件、学习平台、微信群等线上教学工具进行授课及答疑,提出了“云查房”“在线问诊”等线上医学实践方法,同时,课程组师资在课程中融入了“课程思政”的内容。结果线上教学总体取得了较好的教学成效,线上教学的2019学生成绩和及格率与线下教学的2018级学生成绩相比,差异有统计学意义(P<0.05)。学生们对线上教学的满意度较高。结论课程组师资创新性地将BOPPPS教学模式拆分融入线上教学课程3个阶段的设计中,加强了师生互动,“课程思政”内容的有机融入进一步提升了教学效果,为今后的线上教学工作提供了丰富的经验与新的思路。

关键词：线上教学课程设计肝胆外科课程思政云查房在线问诊

标准化病人在肝胆外科急重症临床教学中的应用价值

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中国继续医学教育 2024年第7期16卷 129-134页

作者：何堃丁雄李金政重庆医科大学附属第二医院肝胆外科重庆400010

目的探讨标准化病人在肝胆外科急重症临床教学中的应用价值。方法选取2022年4—5月在重庆医科大学附属第二医院肝胆外科轮转的规范化培训学员为研究对象,共40名。将其随机分为研究组与对照组,各20名。研究组教学引入标准化病人,对照组... 详细信息

目的探讨标准化病人在肝胆外科急重症临床教学中的应用价值。方法选取2022年4—5月在重庆医科大学附属第二医院肝胆外科轮转的规范化培训学员为研究对象,共40名。将其随机分为研究组与对照组,各20名。研究组教学引入标准化病人,对照组采用传统的教学方法。出科时比较2组学员的病史采集及体格检查水平,以及标准化病人对学员的医患沟通能力及人文关怀进行评分。结果研究组病史采集成绩高于对照组[(88.70±0.61)分vs.(82.00±0.41)分],体格检查成绩高于对照组[(89.40±0.61)分vs.(82.55±0.39)分],差异有统计学意义(P<0.05)。研究组在医患沟通及人文关怀方面的得分高于对照组,[(13.15±0.32)分vs.(9.15±0.29)分],差异有统计学意义(P<0.05)。问卷调查结果显示,研究组100%(20/20)的学员认为标准化病人的应用可以提高学习兴趣,95%(19/20)的学员认为可以提高临床思维能力,90%(18/20)的学员认为可以提高医患沟通技巧。结论在肝胆外科急重症临床教学中应用标准化病人,可以提高学员的病史采集、体格检查、医患沟通等能力,尤其增强了人文关怀的意识,提高了学员的综合素质。

关键词：标准化病人肝胆外科急重症人文关怀病史采集体格检查

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非合作线谱声源分布式定位方法

应用声学 2024年第3期43卷 654-660页

作者：邹男于金正桑志远李娜苏薪元杨嘉轩惠云梦哈尔滨工程大学水声技术全国重点实验室哈尔滨150001 海洋信息获取与安全工信部重点实验室(哈尔滨工程大学)工业和信息化部哈尔滨150001 哈尔滨工程大学水声工程学院哈尔滨150001

非合作目标定位是水声定位领域的研究热点。为充分挖掘并利用各类可观测参数,提高非合作目标定位能力,提出一种基于目标频率变化信息的非合作目标定位方法。该方法针对匀速直线运动目标的定位问题,首先根据多普勒频移原理,建立观测频率... 详细信息

非合作目标定位是水声定位领域的研究热点。为充分挖掘并利用各类可观测参数,提高非合作目标定位能力,提出一种基于目标频率变化信息的非合作目标定位方法。该方法针对匀速直线运动目标的定位问题,首先根据多普勒频移原理,建立观测频率与目标辐射频率、目标运动速度、位置之间的函数映射关系,利用最小均方准则建立目标函数,通过优化算法估计分布式定位系统中各个测量单元与目标运动轨迹的致近点距离,最后综合各观测节点的测距结果,构建几何定位模型,求得目标运动轨迹的解析解。通过仿真分析,证明了该方法的有效性,并指出了该方法需要目标通过与各测量单元的致近点才能获得较好的距离估计能力。文中分析了不同频率估计精度对定位精度的影响,结果表明,提出的定位方法对测频精度具有一定的容限,是一种高精度的非合作线谱声源定位方法。

关键词：非合作定位被动定位信赖域优化方法被动测距目标运动分析

Study on influencing factors and prediction of peak particle velocity induced by roof pre-split blasting in underground

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Underground Space 2022年第6期7卷 1068-1085页

作者： Jiliang Kan linming Dou Xuwei li Jinrong Cao jinzheng Bai Yanjiang Chai Key Laboratory of Deep Coal Resource Mining Ministry of EducationChina University of Mining and TechnologyXuzhou 221116China School of Mines China University of Mining and TechnologyXuzhou 221116China

Blasting technology is widely used to prevent coal bursts by presplitting the overburden in underground coal mines.The control of blasting intensity is important in achieving the optimal pre-split effectiveness and reducing the damage to roadway structures that are subjected to blasting vibrations.As a critical parameter to measure the blasting intensity,the peak particle velocity(PPV)of vibration induced by blasting,should be accurately predicted,and can provide a useful guideline for the design of blasting parameters and the evaluation of the damage.In this paper,various factors that influence PPV,induced by roof pre-split blasting,were analyzed using engineering blasting experiments and numerical simulations.The results showed that PPV was affected by many factors,including charge distribution design(total charge and maximum charge per hole),spacing of explosive centers,as well as propagation distance and path.Two parameters,average charge coefficient and spatial discretization coefficient were used to quantitatively characterize the influences of charge distribution and spacing of explosive centers on the PPV induced by roof pre-split blasting.Then,a model consisting of the combination of artificial neural network(ANN)and genetic algorithm(GA)was adopted to predict the PPV that was induced by roof presplit blasting.A total of 24 rounds of roof pre-split blasting experiments were carried out in a coal mine,and vibration signals were collected using a microseismic(MS)monitoring system to construct the neural network datasets.To verify the efficiency of the proposed GA-ANN model,empirical correlations were applied to predict PPV for the same datasets.The results showed that the GA-ANN model had superiority in predicting PPV compared to empirical correlations.Finally,sensitivity analysis was performed to evaluate the impacts of input parameters on PPV.The research results are of great significance to improve the prediction accuracy of PPV induced by roof pre-splitting blasting.

关键词： Roof pre-split blasting Peak particle velocity GA-ANN model Sensitivity analysis