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Effect and mechanism of on-chip electrostatic discharge protection circuit under fast rising time electromagnetic pulse
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作者 Mao Xinyi Chai Changchun +3 位作者 Li Fuxing Lin Haodong Zhao Tianlong Yang Yintang 《强激光与粒子束》 CAS CSCD 北大核心 2024年第10期44-52,共9页
The electrostatic discharge(ESD)protection circuit widely exists in the input and output ports of CMOS digital circuits,and fast rising time electromagnetic pulse(FREMP)coupled into the device not only interacts with ... The electrostatic discharge(ESD)protection circuit widely exists in the input and output ports of CMOS digital circuits,and fast rising time electromagnetic pulse(FREMP)coupled into the device not only interacts with the CMOS circuit,but also acts on the protection circuit.This paper establishes a model of on-chip CMOS electrostatic discharge protection circuit and selects square pulse as the FREMP signals.Based on multiple physical parameter models,it depicts the distribution of the lattice temperature,current density,and electric field intensity inside the device.At the same time,this paper explores the changes of the internal devices in the circuit under the injection of fast rising time electromagnetic pulse and describes the relationship between the damage amplitude threshold and the pulse width.The results show that the ESD protection circuit has potential damage risk,and the injection of FREMP leads to irreversible heat loss inside the circuit.In addition,pulse signals with different attributes will change the damage threshold of the circuit.These results provide an important reference for further evaluation of the influence of electromagnetic environment on the chip,which is helpful to carry out the reliability enhancement research of ESD protection circuit. 展开更多
关键词 fast rising time electromagnetic pulse damage effect electrostatic discharge protection circuit damage location prediction
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Residence time distribution of high viscosity fluids falling film flow down outside of industrial-scale vertical wavy wall: Experimental investigation and CFD prediction 被引量:5
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作者 Shichang Chen Lihao Zhang +2 位作者 Yongjun Wang Xianming Zhang Wenxing Chen 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2019年第7期1586-1594,共9页
The flow behavior of gravity-driven falling film of non-conductive high viscosity polymer fluids on an industrial-scale vertical wavy wall was investigated in terms of film thickness and residence time distribution by... The flow behavior of gravity-driven falling film of non-conductive high viscosity polymer fluids on an industrial-scale vertical wavy wall was investigated in terms of film thickness and residence time distribution by numerical simulation and experiment.Falling film flow of high viscosity fluids was found to be steady on a vertical wavy wall in the presence of the large film thickness.The comparison between numerical simulation and experiment for the film thickness both in crest and trough of wavy wall showed good agreement.The simulation results of average residence time of falling film flow with different viscous fluids were also consistent with the experimental results.This work provides the initial insights of how to evaluate and optimize the falling film flow system of polymer fluid. 展开更多
关键词 falling FILM flow High viscosity polymer fluid RESIDENCE time distribution FILM thickness Numerical simulation
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Homing Guidance Law with Falling Angle and Flying Time Control 被引量:3
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作者 Peng-Yun Liu Rui-Sheng Sun Wei-Ming Li 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2014年第1期55-61,共7页
In this paper,a new homing guidance method is used to control the flying time and falling angle for guided missiles. Through this approach,it finds the approximate solution to the quadratic equation of time-togo,which... In this paper,a new homing guidance method is used to control the flying time and falling angle for guided missiles. Through this approach,it finds the approximate solution to the quadratic equation of time-togo,which is used for the formula derivation of the flying time control command. In this guidance law design,the acceleration rate control command is adopted. The guidance law is composed of a PN guidance command and a flying time control command. Firstly,it obtains a desired falling angle with accurate guidance. Secondly,it introduces to satisfy the constraint of flying time. The flying time control requires an assumption on the future evolution of missile,which is called time-to-go. To cope with the time-varying speed of missiles,a method of compensating the estimation of time-to-go is presented. The new guidance law is evaluated by using a simulation of typical terminal guidance for rocket-propelled torpedo. The simulation results show that the guidance achieves excellent control performance and exhibits insensitivity to initial trajectory parameter over a widen flight envelope. 展开更多
关键词 homing guidance law falling angle flying time rocket-propelled torpedo time-TO-GO
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Navigating Temporal and Spatial Dimensions:Unveiling the Fictional Essence and Authenticity in the Narrative of The Rise and Fall of Wing Shing Street
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作者 Xiaohan Lu Jing Yang 《Journal of Contemporary Educational Research》 2023年第11期6-10,共5页
The novel The Rise and Fall of Wing Shing Street delves into the reality of Hong Kong residents deeply attuned to spatial awareness but detached from temporal significance,entangling emotions surrounding time and spac... The novel The Rise and Fall of Wing Shing Street delves into the reality of Hong Kong residents deeply attuned to spatial awareness but detached from temporal significance,entangling emotions surrounding time and space.Through narrative interruption and extension,the author portrays the genuine struggles of Hong Kong inhabitants-juxtaposing the blurred boundaries of time and space and the inherent rootlessness of reality within a fictionalized framework.Emphasizing the 20th-century human condition,wherein spatial awareness overshadows temporal understanding,the novel underscores the consequences:a loss of history and cultural identity.With a fresh perspective,the narrative explores the interplay of time and space,accentuating both the fictitious and authentic dimensions.This prompts readers to reconsider their history,culture,and the current moment,ultimately highlighting the pivotal role of temporal awareness. 展开更多
关键词 The Rise and fall of Wing Shing Street Spatial awareness Temporal awareness Rootlessness Cultural identity Return of the heart
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Partial Bell Polynomials, Falling and Rising Factorials, Stirling Numbers, and Combinatorial Identities
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作者 Siqintuya Jin Bai-Ni Guo Feng Qi 《Computer Modeling in Engineering & Sciences》 SCIE EI 2022年第9期781-799,共19页
In the paper,the authors collect,discuss,and find out several connections,equivalences,closed-form formulas,and combinatorial identities concerning partial Bell polynomials,falling factorials,rising factorials,extende... In the paper,the authors collect,discuss,and find out several connections,equivalences,closed-form formulas,and combinatorial identities concerning partial Bell polynomials,falling factorials,rising factorials,extended binomial coefficients,and the Stirling numbers of the first and second kinds.These results are new,interesting,important,useful,and applicable in combinatorial number theory. 展开更多
关键词 Connection EQUIVALENCE closed-form formula combinatorial identity partial Bell polynomial falling factorial rising factorial binomial coefficient Stirling number of the first kind Stirling number of the second kind problem
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Effect of pulse voltage rising time on discharge characteristics of a helium-air plasma at atmospheric pressure 被引量:1
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作者 Muyang QIAN Gui LI +4 位作者 Sanqiu LIU Yu ZHANG Shan LI Zebin LIN Dezhen WANG 《Plasma Science and Technology》 SCIE EI CAS CSCD 2017年第6期102-107,共6页
In this paper,the influence of voltage rising time on a pulsed-dc helium-air plasma at atmospheric pressure is numerically simulated.Simulation results show that as the voltage rising time increases from 10 ns to 30 n... In this paper,the influence of voltage rising time on a pulsed-dc helium-air plasma at atmospheric pressure is numerically simulated.Simulation results show that as the voltage rising time increases from 10 ns to 30 ns,there is a decrease in the discharge current,namely 0.052 A when the voltage rising time is 10 ns and 0.038 A when the voltage rising time is 30 ns.Additionally,a shorter voltage rising time results in a faster breakdown,a more rapidly rising current waveform,and a higher breakdown voltage.Furthermore,the basic parameters of the streamer discharge also increase with voltage rise rate,which is ascribed to the fact that more energetic electrons are produced in a shorter voltage rising time.Therefore,a pulsed-dc voltage with a short rising time is desirable for efficient production of nonequilibrium atmospheric pressure plasma discharge. 展开更多
关键词 atmospheric pressure plasma discharge voltage rising time numerical simulation
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Scaling of rise time of drive current on development of magneto-Rayleigh–Taylor instabilities for single-shell Z-pinches 被引量:1
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作者 Xiaoguang Wang Guanqiong Wang +4 位作者 Shunkai Sun Delong Xiao Ning Ding Chongyang Mao Xiaojian Shu 《Chinese Physics B》 SCIE EI CAS CSCD 2022年第2期471-479,共9页
In fast Z-pinches,rise time of drive current plays an important role in development of magneto-Rayleigh–Taylor(MRT)instabilities.It is essential for applications of Z-pinch dynamic hohlraum(ZPDH),which could be used ... In fast Z-pinches,rise time of drive current plays an important role in development of magneto-Rayleigh–Taylor(MRT)instabilities.It is essential for applications of Z-pinch dynamic hohlraum(ZPDH),which could be used for driving inertial confinement fusion(ICF),to understand the scaling of rise time on MRTs.Therefore,a theoretical model for nonlinear development of MRTs is developed according to the numerical analysis.It is found from the model that the implosion distance L=r_(0)-r_(mc)determines the development of MRTs,where r_(0)is the initial radius and rmc is the position of the accelerating shell.The current rise timeτwould affect the MRT development because of its strong coupling with the r;.The amplitude of MRTs would increase with the rise time linearly if an implosion velocity is specified.The effects of the rise time on MRT,in addition,are studied by numerical simulation.The results are consistent with those of the theoretical model very well.Finally,the scaling of the rise time on amplitude of MRTs is obtained for a specified implosion velocity by the theoretical model and numerical simulations. 展开更多
关键词 magneto-Rayleigh-Taylor instability rise time Z-PINCH MAGNETOHYDRODYNAMIC
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Effects of drive current rise-time and initial load density distribution on Z-pinch characteristics 被引量:1
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作者 段耀勇 郭永辉 +1 位作者 王文生 邱爱慈 《Chinese Physics B》 SCIE EI CAS CSCD 2005年第9期1856-1861,共6页
A two-dimensional, three-temperature radiation magneto-hydrodynamics model is applied to the investigation of evolutional trends in x-ray radiation power, energy, peak plasma temperature and density as functions of dr... A two-dimensional, three-temperature radiation magneto-hydrodynamics model is applied to the investigation of evolutional trends in x-ray radiation power, energy, peak plasma temperature and density as functions of drive current rise-time and initial load density distribution by using the typical experimental parameters of tungsten wire-array Z- pinch on the Qiangguang-I generator. The numerical results show that as the drive current rise-time is shortened, x-ray radiation peak power, energy, peak plasma density and peak ion temperature increase approximately linearly, but among them the x-ray radiation peak power increases more quickly. As the initial plasma density distribution in the radial direction becomes gradually flattened, the peak radiation power and the peak ion-temperature almost exponentially increase, while the radiation energy and the peak plasma density change only a little. The main effect of shortening drive current rise-time is to enhance compression of plasma, and the effect of flattening initial load density distribution in the radial direction is to raise the plasma temperature. Both of the approaches elevate the x-ray peak radiation power 展开更多
关键词 Z-PINCH drive current rise-time initial load density distribution numerical simulation
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Night-time Rise in Rat Pineal N-Acetyltransferase due to Carbaryl Administration Is Reduced by Propranolol Treatment
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作者 AHMED M. ATTIA MOSTAFA H. MOSTAFA +2 位作者 BRUCE A. RICHARDSON AND RUSSEL J. REITER(Department of Environmental Studies, Institute of Graduate Studies and Research, P.O.Box 832, Alexandria, Egypt Department of Cellular and Structural Biology, University of Texas, 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 1995年第1期45-53,共9页
The purpose of the present study was to examine the effects of administration of sublethal doses of carbaryl on nighttime rat pineal melatonin synthesis in the presence and absence of propranolol, a β-adrenergic rece... The purpose of the present study was to examine the effects of administration of sublethal doses of carbaryl on nighttime rat pineal melatonin synthesis in the presence and absence of propranolol, a β-adrenergic receptor antagonist. Two groups of adult male albino rats were administered orally N-methyl-l-naphthylcarbamate (carbaryl) (8. 33mg/kg BW daily in corn oil) for six successive days; another two groups received corn oil only.On the last day of carbaryl treatment, half of the animals received an intraperitoneal injection of propranolol (20 mg/kg body weight, one hour before lights off). The other two groups were given a saline injection. Four hours after darkness onset, pineal N-acetyltransferase (NAT) and hydroxyindole-O-methyltransferase (HIOMT) activities as well as pineal concentrations of 5-hydroxytryptophan (5HTP), serotonin (5HT),5-hydroxyindole acetic acid (5HIAA) and pineal and serum melatonin levels were measured. Nocturnal NAT activity was increased due to carbaryl administration but the pesticide was ineffective in stimulating NAT activity in rats treated with propranolol.Pineal 5HT was decreased due to carbaryl administration but 5HTP and 5HIAA levels were unaffected. Pineal and serum melatonin levels were decreased due to propranolol treatment. The results indicate that carbaryl may influence pineal NAT activity by a mechanism that involves β-adrenergic neural transmission. 展开更多
关键词 time Night-time Rise in Rat Pineal N-Acetyltransferase due to Carbaryl Administration Is Reduced by Propranolol Treatment
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A RISE TO THE TIMES Harnessing the power of all civilizations is a savvy strategy to tackle today’s global challenges
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作者 Fan Zongding 《China Report ASEAN》 2019年第6期16-17,共2页
“Civilizations only vary from each other, just as human beings are different only in terms of skin color and the language used,” declared Xi Jinping in his May 15 keynote speech at the opening ceremony of the Confer... “Civilizations only vary from each other, just as human beings are different only in terms of skin color and the language used,” declared Xi Jinping in his May 15 keynote speech at the opening ceremony of the Conference on Dialogue of Asian Civilizations (CDAC) in Beijing, to a boisterous response.“No civilization is superior over others,” he continued as the enthusiasm swelled. 展开更多
关键词 RISE THE timeS CIVILIZATIONS
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On the Rise and Fall of Great Britain
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作者 张颖 《海外英语》 2019年第17期196-198,共3页
From the Industrial Revolution to the World War,the past three centuries have witnessed the development and rise and fall of Great Britain.Great Britain,an island country with a total area of about 240,000 square kilo... From the Industrial Revolution to the World War,the past three centuries have witnessed the development and rise and fall of Great Britain.Great Britain,an island country with a total area of about 240,000 square kilometers,enjoys a very important place in the world in modern history.Great Britain was the first industrial country and created the epoch-making laissez-faire capitalism and built a sun-never-set empire.It was also the leadership of the world from the middle of 18^th and to the middle of 19^th century.In retrospect to the rise of Great Britain,we can easily see that it was by relying on an innovative culture that the island country became a great power in Europe and then became the dominant empire in the world.This innovative character permeates in all kinds of culture including industrial,military,technological,politic and diplomatic.As for the main cause of Great Britain’s rise,this thesis attempts to analyze from three aspects,that is,the emancipation of mind,the advancement of military power,and the development of technology.After the World War,Great Britain began to suffer a decline in status and was reduced to a second class developed country.That is also because the conservative factor in its culture which blocks its development and the potential to innovate new things.The past years has witnessed the fall of the empire and also left us much inspiration.Take the history as a mirror,the thesis will focus on the“English disease”and influence of the World War to make an analysis on Great Britain’s fall.A conclusion of inspiration would also be included. 展开更多
关键词 GREAT BRITAIN RISE fall INSPIRATION
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Analog rise-time discriminator for CdZnTe detector
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作者 Chuan-Hao Hu Guo-Qiang Zeng +4 位作者 Liang-Quan Ge Shi-Long Wei Jian Yang Qiang Li Hong-Zhi Li 《Nuclear Science and Techniques》 SCIE CAS CSCD 2017年第4期59-65,共7页
Due to variable time for charge collection,energy resolution of nuclear detectors declines,especially compound semiconductor detectors like cadmium zinc telluride(CdZnTe) detector.To solve this problem,an analog rise-... Due to variable time for charge collection,energy resolution of nuclear detectors declines,especially compound semiconductor detectors like cadmium zinc telluride(CdZnTe) detector.To solve this problem,an analog rise-time discriminator based on charge comparison principle is designed.The reference charge signal after attenuation is compared with the deconvoluted and delayed current signal.It is found that the amplitude of delayed current signal is higher than that of the reference charge signal when rise time of the input signal is shorter than the discrimination time,thus generating gating signal and triggering DMCA(digital multi-channel analyzer) to receive the total integral charge signal.When rise time of the input signal is longer than discrimination time,DMCA remains inactivated and the corresponding total integral charge signal is abandoned.Test results show that combination of the designed rise-time discriminator and DMCA can reduce hole tailing of CdZnTe detector significantly.Energy resolution of the system is 0.98%@662 keV,and it is still excellent under high counting rates. 展开更多
关键词 ANALOG rise-time DISCRIMINATOR CDZNTE detector Charge comparison PRINCIPLE
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The effect of pulse voltage rise rate on the polypropylene surface hydrophilic modification by ns pulsed nitrogen DBD
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作者 刘峰 李舒豪 +3 位作者 赵昱雷 Shakeel AKRAM 张丽 方志 《Plasma Science and Technology》 SCIE EI CAS CSCD 2023年第10期6-14,共9页
The nanosecond(ns) pulsed nitrogen dielectric barrier discharge(DBD) is employed to enhance the hydrophilicity of polypropylene(PP) surface and improve its application effect.The discharge characteristics of the ns pu... The nanosecond(ns) pulsed nitrogen dielectric barrier discharge(DBD) is employed to enhance the hydrophilicity of polypropylene(PP) surface and improve its application effect.The discharge characteristics of the ns pulsed nitrogen DBD with different pulse rise times(from 50to 500 ns) are investigated by electrical and optical diagnostic methods and the discharge uniformity is quantitatively analyzed by image processing method.To characterize the surface hydrophilicity,the water contact angle(WCA) is measured,and the physical morphology and chemical composition of PP before and after modification are analyzed to explore the effect of plasma on PP surface.It is found that with increasing pulse rise time from 50 to 500 ns,DBD uniformity becomes worse,energy efficiency decreases from 20% to 10.8%,and electron density decrease from 6.6 × 10^(11)to 5.5 × 10^(11)cm^(-3).The tendency of electron temperature is characterized with the intensity ratio of N_(2)/N_(2)^(+)emission spectrum,which decreases from 17.4 to15.9 indicating the decreasing of T_(e) with increasing pulse rise time from 50 to 500 ns.The PP surface treated with 50 ns pulse rise time DBD has a lower WCA(~47°),while the WCA of PP treated with 100 to 500 ns pulse rise time DBD expands gradually(~50°–57°).According to the study of the fixed-point WCA values,the DBD-treated PP surface has superior uniformity under50 ns pulse rise time(3° variation) than under 300 ns pulse rise time(8° variation).After DBD treatment,the increased surface roughness from 2.0 to 9.8 nm and hydrophilic oxygencontaining groups on the surface,i.e.hydroxyl(-OH) and carbonyl(C=O) have played the significant role to improve the sample’s surface hydrophilicity.The short pulse voltage rise time enhances the reduced electric field strength(E/n) in the discharge space and improves the discharge uniformity,which makes relatively sufficient physical and chemical reactions have taken place on the PP surface,resulting in better treatment uniformity. 展开更多
关键词 dielectric barrier discharge pulse rise time material surface modification POLYPROPYLENE UNIFORMITY
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基于子循环自适应串行交错时间匹配算法的油浸式变压器绕组瞬态温升计算 被引量:3
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作者 刘刚 郝世缘 +2 位作者 胡万君 刘云鹏 李琳 《电工技术学报》 EI CSCD 北大核心 2024年第4期1185-1197,共13页
针对传统算法存在的步长调整及耦合点选择问题,该文提出基于子循环自适应串行交错(SCAS)的时间匹配算法。首先,在步长调整方面,通过加入自适应(ATS)-启发式(HTS)混合变步长算法,解决步长无法实时调整的问题;然后,针对耦合点选择问题,该... 针对传统算法存在的步长调整及耦合点选择问题,该文提出基于子循环自适应串行交错(SCAS)的时间匹配算法。首先,在步长调整方面,通过加入自适应(ATS)-启发式(HTS)混合变步长算法,解决步长无法实时调整的问题;然后,针对耦合点选择问题,该文在传统常规串行交错(CSS)时间匹配算法及现有改进方案子循环常规串行交错(SCSS)的基础上,提出SCAS时间匹配算法,采用自适应方案确定计算时间窗及预定耦合点,并引入指数平滑法对其精度进行保证;最后,该文基于110 kV油浸式电力变压器建立二维瞬态单分区分匝绕组模型,并将所提算法与其他传统方法进行对比分析。结果表明:在精度方面,与传统CSS算法相比SCAS算法的流场及温度场最大平均相对误差均不超过0.45%,在可接受误差范围内;在效率方面,SCAS算法总体计算效率较CSS算法提高了近20倍。同时,为了说明所提算法的工程价值,该文搭建基于110 kV变压器绕组模型的温升实验平台,将SCAS时间匹配算法应用于该模型中,实验结果表明:在精度方面,SCAS算法与实验达到稳态时最大绝对误差为2.7 K;在计算效率上,本文所提算法的计算效率较传统算法提升约46倍,计算步数约为传统的1/47,减少了计算冗余。 展开更多
关键词 子循环自适应串行交错 混合变步长 二维瞬态流热耦合问题 快速计算方法 温升实验
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自我革命:跳出治乱兴衰历史周期率的第二个答案 被引量:1
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作者 赵卯生 范明洋 《新疆师范大学学报(哲学社会科学版)》 CSSCI 北大核心 2024年第2期37-47,F0002,共12页
中国共产党在百余年奋斗历程中始终保持高度的居安思危意识,从未停止对跳出历史周期率的探索和思考,并以实际行动回应这一重大考题。在毛泽东同志给出“人民监督”民主新路跳出历史周期率的第一个答案的基础上,习近平总书记给出“自我... 中国共产党在百余年奋斗历程中始终保持高度的居安思危意识,从未停止对跳出历史周期率的探索和思考,并以实际行动回应这一重大考题。在毛泽东同志给出“人民监督”民主新路跳出历史周期率的第一个答案的基础上,习近平总书记给出“自我革命”从严治党跳出历史周期率的第二个答案。自我革命彰显了党始终坚守人民立场的价值取向与历史自觉,构成中国共产党区别于其他政党的显著标志,成为管党治党兴党强党的集中体现。自我革命与人民监督同心同源、情理相依,内呼外应、水乳交融,共同归向人民幸福与民族复兴,一道构成长治久安的动力源泉,协同彰显党鲜明的历史主动精神与创造精神。新时代党的自我革命应在坚持党性与人民性的统一、集中领导与党内民主的统一、思想武装与制度保障的统一、问题导向与全面深化的统一中进行到底,确保党跳出历史周期率实现长期执政,始终成为中国特色社会主义事业的坚强领导核心,永远做中国人民和中华民族的主心骨。 展开更多
关键词 中国共产党 历史周期率 长期执政 自我革命 人民监督
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大党“破题之钥”:以全过程人民民主健全全面从严治党体系 被引量:1
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作者 刘伟 何頔 《党政研究》 北大核心 2024年第4期50-60,125,126,共13页
如何跳出治乱兴衰历史周期率,破解大党独有难题,是中国共产党坚持探索的重要问题,也是关系民族复兴大业的关键所在。基于对大党独有难题理论意蕴的把握,可以发现,全过程人民民主和全面从严治党是在实践中形成的跳出历史周期率的“两个... 如何跳出治乱兴衰历史周期率,破解大党独有难题,是中国共产党坚持探索的重要问题,也是关系民族复兴大业的关键所在。基于对大党独有难题理论意蕴的把握,可以发现,全过程人民民主和全面从严治党是在实践中形成的跳出历史周期率的“两个答案”:全面从严治党具有从严以尚贤、任贤而兴民、民主护安邦的思想基础,并蕴含在其全面性、严格性和治理性的内在特质之中;而全过程人民民主既为全面从严治党提供了实践标尺,同时其发展也需要以全面从严治党作为保障。未来应通过发展维护党的全面领导的有效体制机制,探索人民群众监督与党内监督有机结合的有效方式,拓宽全面从严治党“靠人民”的有效渠道,进一步以全过程人民民主健全全面从严治党体系,将中国共产党的执政优势转化为实现中华民族伟大复兴的强大动能。 展开更多
关键词 全过程人民民主 全面从严治党 大党独有难题 历史周期率 自我革命
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不同浓度离子溶液中气泡运动特性的实验研究
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作者 高丹 戈立宁 +2 位作者 潘勇 张衡 张宇宁 《华北电力大学学报(自然科学版)》 CAS 北大核心 2024年第5期134-142,共9页
气泡运动特性可以分析流型形成和演化,是探究两相流模型构建的基础。为了进一步研究气泡在多种溶液内的运动特性,搭建了气泡运动特性实验平台。在3种浓度的FeCl_(3)、CaCl_(2)、NH_(4)Cl离子溶液及去离子水内,对单个气泡运动特性进行了... 气泡运动特性可以分析流型形成和演化,是探究两相流模型构建的基础。为了进一步研究气泡在多种溶液内的运动特性,搭建了气泡运动特性实验平台。在3种浓度的FeCl_(3)、CaCl_(2)、NH_(4)Cl离子溶液及去离子水内,对单个气泡运动特性进行了实验研究,利用高速相机拍摄图片并导入MATLAB软件进行了计算。据此,分析了离子溶液内单个气泡的上升时间,脱离时间,初始当量直径,以及纵横比。结果表明:离子溶液,尤其是CaCl_(2)溶液在一定程度上可以促进气泡在喷嘴处的脱离,使得脱离时间减少,当喷嘴为1.5 mm时,促进作用最为明显;三种离子溶液和去离子水比较,气泡上升时间都有所缩短,但是相差不大;三种离子溶液中,FeCl_(3)溶液中气泡纵横比变化最大;NH_(4)Cl溶液对气泡的当量直径促进作用最强,CaCl_(2)溶液会抑制气泡当量直径的发展,因此在特殊流体机械内部,应适当增加钙离子以降低冲击带来的腐蚀与振动;在去离子水和三种离子溶液中气泡的纵横比δ都会有一个“L”型分布,且最大值均出现在气泡脱离喷嘴的瞬间。 展开更多
关键词 气泡 运动特性 上升时间 脱离时间 纵横比
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大国兴衰与国际秩序的历史演进
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作者 刘德斌 《学术前沿》 CSSCI 北大核心 2024年第6期10-25,共16页
大国兴衰与国际秩序的历史演进有着非常密切的联系。尽管近代以来国际秩序的具体形态不断发生演变,大国之间的力量对比不断发生改变,但欧洲和西方大国始终是国际秩序的主导力量。二战结束之后,摆脱了殖民地或半殖民地地位的非西方大国... 大国兴衰与国际秩序的历史演进有着非常密切的联系。尽管近代以来国际秩序的具体形态不断发生演变,大国之间的力量对比不断发生改变,但欧洲和西方大国始终是国际秩序的主导力量。二战结束之后,摆脱了殖民地或半殖民地地位的非西方大国开始登上世界舞台。冷战结束后,一批非西方大国在新一轮的经济全球化进程中乘势而起,改变了大国之间力量对比结果,促成了“世界百年未有之大变局”的到来。相比于西方大国,非西方大国不仅具有更为广阔和长远的发展优势,更有不同的历史经验和价值追求,从而为国际秩序的发展变化注入了新的活力。而中国提出“人类命运共同体”理念构想和“全球发展倡议”“全球安全倡议”“全球文明倡议”,更是为超越当今世界所面临的挑战和困局,构建更为公正、合理的国际秩序,提供了令人鼓舞的发展目标和前景。 展开更多
关键词 国际秩序 大国兴衰 帝国 西方国家 新兴大国
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民初新式知识分子重释“天下兴亡匹夫有责”论
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作者 赵炎才 《河北学刊》 CSSCI 北大核心 2024年第5期106-114,共9页
民初一些知识分子以报刊为阵地大声疾呼并努力诠释“天下兴亡匹夫有责”。他们赋予此一流行话语以时代新义,其中“天下”与“国家”由异趋同聚合为近代共和国,而“匹夫”则由传统臣民一跃而为近代国民。“天下”与“匹夫”的关系遂转变... 民初一些知识分子以报刊为阵地大声疾呼并努力诠释“天下兴亡匹夫有责”。他们赋予此一流行话语以时代新义,其中“天下”与“国家”由异趋同聚合为近代共和国,而“匹夫”则由传统臣民一跃而为近代国民。“天下”与“匹夫”的关系遂转变为国家与国民的新关系。而近代语境下的“匹夫有责”的“责”则凸显为自觉弘扬中华民族传统优秀道义精神,视其为天赋人权精神中应有之义,具体外现为职责、责任、良心与诚信等道德素养,蕴含着浓郁的政治文化与社会文化等价值诉求。这从一个侧面透露出“天下兴亡匹夫有责”渐成中国近代爱国主义的代名词。 展开更多
关键词 民初 新式知识分子 报刊 “天下兴亡匹夫有责”
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跳出“革命的悖论”和历史周期率——论马克思主义革命党的内涵、使命与价值
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作者 陶元浩 《内蒙古社会科学》 CSSCI 北大核心 2024年第5期84-91,共8页
在人类过往的政治实践中,“革命的悖论”与历史周期率犹如无形之手作用其中,无数政治集团未能逃脱从建政到执政再到丢失政权的命运。与一般政党将执掌政权作为自己最主要的政治目标不同,马克思主义革命党并非“一次革命论”者,不止步于... 在人类过往的政治实践中,“革命的悖论”与历史周期率犹如无形之手作用其中,无数政治集团未能逃脱从建政到执政再到丢失政权的命运。与一般政党将执掌政权作为自己最主要的政治目标不同,马克思主义革命党并非“一次革命论”者,不止步于夺取政权的政治革命胜利,还有更宏伟的社会革命理想以及始终贯穿其中的党的自我革命。基于“革命之后还有革命”的社会革命使命和党自身的革命性锻造,中国共产党努力实现对过往一切政治组织的超越和自我超越,跳出“革命的悖论”和历史周期率成为一种理论和现实的必然。 展开更多
关键词 革命的悖论 历史周期率 马克思主义革命党 政治革命 社会革命 自我革命
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