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Experimental study on the TNT equivalence for blast parameters in a confined space
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作者 Yu-lei Zhang Yan Liu +5 位作者 Pu Song Hao-zhe Liang Di Yang Lu Han Hai-yan Jiang Kai Zhong 《Defence Technology(防务技术)》 2025年第6期238-249,共12页
The concept of TNT(Trinitrotoluene,C_7H_5N_3O_6)equivalence is often invoked to evaluate the performance and predict the explosion parameters of different types of explosives.However,due to its low prediction accuracy... The concept of TNT(Trinitrotoluene,C_7H_5N_3O_6)equivalence is often invoked to evaluate the performance and predict the explosion parameters of different types of explosives.However,due to its low prediction accuracy and limited application range,the use of TNT equivalence for predicting explosion parameters in a confined space is rare.Compared with explosions in free fields,the process of explosive energy release in a confined space is closely related to various factors such as oxygen balance,combustible components content,and surrounding oxygen content.Studies have shown that in a confined space,negative oxygen balance explosives react with surrounding oxygen during afterburning,resulting in additional energy release and enhanced blast effects.The mechanism of energy release during afterburning is highly complex,making it challenging to determine the TNT equivalence for blast effects in a confined space.Therefore,this remains an active area of research.In this study,internal blast experiments were conducted using TNT and three other explosives under both air and N_2(Nitrogen)conditions to obtain explosion parameters including blast wave overpressure,quasi-static pressure,and temperature.The influences of oxygen balance and external oxygen content on energy release are analyzed.The author proposes principles for determining TNT equivalence for internal explosions while verifying the accuracy of obtained blast parameters through calculations based on TNT equivalence.These findings can serve as references for predicting blast performance. 展开更多
关键词 Explosion in confined space AFTERBURNING Oxygen balance Blast parameters TNT equivalence
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A General View of the Equivalence Between Chinese and English 被引量:1
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作者 郭英杰 《陕西师范大学学报(哲学社会科学版)》 CSSCI 北大核心 2002年第S3期71-77,共7页
This paper briefly presents a study of the relationship between English and Chinese, which is put forward from the point of the equivalence in both languages. By observing and analyzing the examples in the parts of fu... This paper briefly presents a study of the relationship between English and Chinese, which is put forward from the point of the equivalence in both languages. By observing and analyzing the examples in the parts of full equivalence and partial equivalence, we can surely conclude that English and Chinese have close relationship with each other. However, the equivalence reflected in the languages is, to some extent, greatly influenced by their respective culture, which still needs us to do more research about it. 展开更多
关键词 equivalence INTERPRETATION PRINCIPLE CULTURE CONTEXT
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The Dynamic Equivalence Translation Theory in Film Name Translation 被引量:1
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作者 郑晓云 《陕西师范大学学报(哲学社会科学版)》 CSSCI 北大核心 2004年第S2期415-417,共3页
Eugene Nida’s dynamic equivalence translation theory has become a mainstream in translation theory field, and is found applied in various fields. The paper is to discuss its application in translating foreign film na... Eugene Nida’s dynamic equivalence translation theory has become a mainstream in translation theory field, and is found applied in various fields. The paper is to discuss its application in translating foreign film names. 展开更多
关键词 Dynamic equivalence TRANSLATION THEORY FOREIGN FILM NAME Chinese version
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Certainty-equivalence方法对经理股票期权价值的确定以及相应激励效果分析 被引量:1
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作者 袁雪璐 李忠民 《科学技术与工程》 2005年第24期1916-1918,1923,共4页
经理股票期权是一种较为先进的薪酬管理制度,但由于其本身所具有的特点,使得利用BS模型对其进行定价会偏离经理人员的人力资本,现介绍Certainty-Equivalence方法来确定ESO的价值,使其更接近人力资本。同时,利用博弈的方法确定经理股票... 经理股票期权是一种较为先进的薪酬管理制度,但由于其本身所具有的特点,使得利用BS模型对其进行定价会偏离经理人员的人力资本,现介绍Certainty-Equivalence方法来确定ESO的价值,使其更接近人力资本。同时,利用博弈的方法确定经理股票期权数量的最佳值,分析了影响经理人员努力程度的相关因素。 展开更多
关键词 经理股票期权价值 Certainty—equivalence方法 激励效果
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Effects of total pressures and equivalence ratios on kerosene/air rotating detonation engines using a paralleling CE/SE method 被引量:11
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作者 Fang Wang Chun-sheng Weng +3 位作者 Yu-wen Wu Qiao-dong Bai Quan Zheng Han Xu 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2021年第6期1805-1816,共12页
In this paper,the kerosene/air rotating detonation engines(RDE)are numerically investigated,and the emphasis is laid on the effects of total pressures and equivalence ratios on the operation characteristics of RDE inc... In this paper,the kerosene/air rotating detonation engines(RDE)are numerically investigated,and the emphasis is laid on the effects of total pressures and equivalence ratios on the operation characteristics of RDE including the initiation,instabilities,and propulsive performance.A hybrid MPI t OpenMP parallel computing model is applied and it is proved to be able to obtain a more effective parallel performance on high performance computing(HPC)systems.A series of cases with the total pressure of 1 MPa,1.5 MPa,2 MPa,and the equivalence ratio of 0.9,1,1.4 are simulated.On one hand,the total pressure shows a significant impact on the instabilities of rotating detonation waves.The instability phenomenon is observed in cases with low total pressure(1 MPa)and weakened with the increase of the total pressure.The total pressure has a small impact on the detonation wave velocity and the specific impulse.On the other hand,the equivalence ratio shows a negligible influence on the instabilities,while it affects the ignition process and accounts for the detonation velocity deficit.It is more difficult to initiate rotating detonation waves directly in the lean fuel operation condition.Little difference was observed in the thrust with different equivalence ratios of 0.9,1,and 1.4.The highest specific impulse was obtained in the lean fuel cases,which is around 2700 s.The findings could provide insights into the understanding of the operation characteristics of kerosene/air RDE. 展开更多
关键词 Kerosene/air rotating detonation waves Total pressure equivalence ratio INSTABILITIES MPItOpenMP
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Effect of equivalence ratio on diesel direct injection spark ignition combustion 被引量:2
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作者 CHEN Zheng QIN Tao +1 位作者 HE Ting-pu ZHU Li-jing 《Journal of Central South University》 SCIE EI CAS CSCD 2020年第8期2338-2352,共15页
Aviation heavy-fuel spark ignition(SI)piston engines have been paid more and more attention in the area of small aviation.Aviation heavy-fuel refers to aviation kerosene or light diesel fuel,which is safer to use and ... Aviation heavy-fuel spark ignition(SI)piston engines have been paid more and more attention in the area of small aviation.Aviation heavy-fuel refers to aviation kerosene or light diesel fuel,which is safer to use and store compared to gasoline fuel.And diesel fuel is more suitable for small aviation application on land.In this study,numerical simulation was performed to evaluate the possibility of switching from gasoline direct injection spark ignition(DISI)to diesel DISI combustion.Diesel was injected into the cylinder by original DI system and ignited by spark.In the simulation,computational models were calibrated by test data from a DI engine.Based on the calibrated models,furthermore,the behavior of diesel DISI combustion was investigated.The results indicate that diesel DISI combustion is slower compared to gasoline,and the knock tendency of diesel in SI combustion is higher.For a diesel/air mixture with an equivalence ratio of 0.6 to 1.4,higher combustion pressure and faster burning rate occur when the equivalence ratios are 1.2 and 1.0,but the latter has a higher possibility of knock.In summary,the SI combustion of diesel fuel with a rich mixture can achieve better combustion performance in the engine. 展开更多
关键词 DIESEL direct injection spark ignition equivalence ratio COMBUSTION KNOCK
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Approximate trace and singleton failures equivalences for transition systems 被引量:2
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作者 Chao Wang Jinzhao Wu Hongyan Tan 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2015年第4期886-896,共11页
Established system equivalences for transition systems, such as trace equivalence and failures equivalence, require the ob- servations to be exactly identical. However, an accurate measure- ment is impossible when int... Established system equivalences for transition systems, such as trace equivalence and failures equivalence, require the ob- servations to be exactly identical. However, an accurate measure- ment is impossible when interacting with the physical world, hence exact equivalence is restrictive and not robust. Using Baire met- ric, a generalized framework of transition system approximation is proposed by developing the notions of approximate language equivalence and approximate singleton failures (SF) equivalence. The framework takes the traditional exact equivalence as a special case. The approximate language equivalence is coarser than the approximate Slc equivalence, just like the hierarchy of the exact ones. The main conclusion is that the two approximate equiva- lences satisfy the transitive property, consequently, they can be successively used in transition system approximation. 展开更多
关键词 approximate equivalence TRACE singleton failures(SF) transition systems.
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Numerical simulation on the combustion characteristics of scramjet at high Mach number
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作者 Jiahang Li Zhaoyang Xia +3 位作者 Mi Yan Hao Zhang Jinfeng Dang Majie Zhao 《Defence Technology(防务技术)》 2025年第8期155-165,共11页
To investigate the problem of ethylene jet mixing and combustion in the scramjet at high Mach number(Ma = 8), numerical simulations were carried out for different equivalent ratios at cold and combustion conditions, i... To investigate the problem of ethylene jet mixing and combustion in the scramjet at high Mach number(Ma = 8), numerical simulations were carried out for different equivalent ratios at cold and combustion conditions, in which three-dimensional steady compressible RANS and k-ω SST turbulence model were adopted. It demonstrates that as the equivalence ratio increases from 0.42 to 1.08, the combustion becomes more intensified, and the higher backpressure pushes flame to propagate upstream. The supersonic combustion region in the combustor decreases from 92% to 85% with the increase of equivalence ratio from 0.42 to 1.08, resulting in the transition of the combustor from scram-mode to dual-mode. Both mixing and combustion efficiencies decrease by 35% and 16% respectively when the equivalence ratio increases from 0.42 to 1.08, indicating that the high equivalence ratio is unfavorable to the mixing and combustion processes. Combustion mode analysis reveals that the flame in the cavity under the high Mach number is dominated by non-premixed flames, i.e., more than 95% behaves as non-premixed mode, and the heat release is also mainly contributed by non-premixed flame. Increasing the equivalence ratio is beneficial to the thrust performance. Although the viscous force hardly changes with equivalence ratio, the percentage of pressure force used to balance the viscous force increases gradually,which limits the engine performance. 展开更多
关键词 SCRAMJET High Mach number equivalence ratio Combustion mode Flame structure
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Dynamic behavior of a battery pack based on single reference impact testing of a secondary cell
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作者 Zhen Xiao Wen-rong Fan Wei-song Hu 《中国科学技术大学学报》 北大核心 2025年第2期44-50,43,I0002,共9页
The mechanical properties of secondary cells are crucial to the safety and reliability of battery packs,which can fail due to extrusion and vibration in a vehicle crash.To analyze the structural response of the second... The mechanical properties of secondary cells are crucial to the safety and reliability of battery packs,which can fail due to extrusion and vibration in a vehicle crash.To analyze the structural response of the secondary cell and its other dynamic behaviors,the experiment and some numerical simulations were carried out based on single reference impact testing.Then,an equivalent constitutive relationship of the secondary cell was proposed to reveal the dynamic properties and used to guide the safety estimation of the battery pack.As the input parameter to the finite element model,the equivalent constitutive relationship,including but not limited to the elastic modulus and stain-stress curve,determines the simulation precision of the battery packs.Compared to the experimental results of the natural frequency of the battery pack,the simulation error is below 2%when the elastic modulus of the secondary cell in the battery pack has been verified. 展开更多
关键词 equivalent constitutive relationship secondary cell dynamic property
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Health Phys. Abstracts,Volume 128,Number 5
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《辐射防护》 北大核心 2025年第4期440-444,共5页
Evaluation of a Commercially Available Radiochromic Film for Use as a Complementary Dosimeter for Rapid In-field Low Photon Equivalent Radiation Dose (≤50 mSv) Monitoring Nicky Nivi1, Helen Moise1,2, Ana Pejovic'... Evaluation of a Commercially Available Radiochromic Film for Use as a Complementary Dosimeter for Rapid In-field Low Photon Equivalent Radiation Dose (≤50 mSv) Monitoring Nicky Nivi1, Helen Moise1,2, Ana Pejovic'-Milic'1(1. Department of Physics, Toronto Metropolitan University, 350 Victoria Street, Toronto, Ontario, M5B 2K3;2. Autonomous and Radiological Technologies Section, Defense Research and Development Canada, PO Box 4000 Stn Main,Medicine Hat, Alberta, T1A 8K6). 展开更多
关键词 low photon equivalent radiation dose autonomous radiological technologies complementary dosimeter DOSIMETER field monitoring radiochromic film
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论三种翻译模式的主要异同(英文) 被引量:6
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作者 区林 陈燕 《思想战线》 CSSCI 北大核心 2010年第S1期267-269,共3页
The Jerome model, the Horace model and the Schleiermacher model are among the most popular translation models, which have exerted their different influences at different historical periods. This paper analyzes their m... The Jerome model, the Horace model and the Schleiermacher model are among the most popular translation models, which have exerted their different influences at different historical periods. This paper analyzes their main differences and similarities that find expression in their different criteria of "faithfulness" or "equivalence"and discusses their different roles in translation practice. The paper concludes that no single translation model is really better than another because the criteria of translation are dynamic rather than static. 展开更多
关键词 Jerome MODEL HORACE MODEL Schleiermacher MODEL FAITHFULNESS equivalence
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论“杰罗姆模式”和“贺拉斯模式”的主要异同--以大学英语翻译教学为例(英文) 被引量:5
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作者 区林 陈燕 《思想战线》 CSSCI 北大核心 2010年第S2期219-220,共2页
The Jerome model and the Horace model are very popular translation models and have exerted different influences on translation theories and practice.This paper analyzes their main differences and similarities in terms... The Jerome model and the Horace model are very popular translation models and have exerted different influences on translation theories and practice.This paper analyzes their main differences and similarities in terms of their different criteria of'faithfulness'and'equivalence'.Through a case study,it concludes that a proper application of the two models to College - English Translation Teaching will help improve the teaching quality and the students’ translation ability. 展开更多
关键词 Jerome MODEL HORACE MODEL TRANSLATION FAITHFULNESS equivalence
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Equivalent loading method for the thin-walled floors of armored vehicles with bottom explosion impacts
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作者 Weiwei Qin Jiahao He +6 位作者 Shaoyan Zhang Tuzao Yao Jing Tang Xianhui Wang Xiaowang Sun Tao Wang Qiang Zhou 《Defence Technology(防务技术)》 2025年第10期184-206,共23页
The high cost and low efficiency of full-scale vehicle experiments and numerical simulations limit the efficient development of armored vehicle occupant protection systems.The floor-occupant-seat local simulation mode... The high cost and low efficiency of full-scale vehicle experiments and numerical simulations limit the efficient development of armored vehicle occupant protection systems.The floor-occupant-seat local simulation model provides an alternative solution for quickly evaluating the performance of occupant protection systems.However,the error and rationality of the loading of the thin-walled floor in the local model cannot be ignored.This study proposed an equivalent loading method for the local model,which includes two parts:the dimensionality reduction method for acceleration matrix and the joint optimization framework for equivalent node coordinates.In the dimensionality reduction method,the dimension of the acceleration matrix was reduced based on the improved kernel principal component analysis(KPCA),and a dynamic variable bandwidth was introduced to address the limitation of failing to effectively measure the similarity between acceleration data in conventional KPCA.In addition,a least squares problem with forced displacement constraints was constructed to solve the correction matrix,thereby achieving the scale restoration process of the principal component acceleration matrix.The joint optimization framework for coordinates consists of the error assessment of response time histories(EARTH)and Bayesian optimization.In this framework,the local loading error of the equivalent acceleration matrix is taken as the Bayesian optimization objective,which is quantified and scored by EARTH.The expected improvement acquisition function was used to select the new set of the equivalent acceleration node coordinates for the self-updating optimization of the observation dataset and Gaussian process surrogate model.We reduced the dimension of the acceleration matrix from 2256 to 7,while retaining 91%of the information features.The comprehensive error score of occupant's lower limb response in the local model increased from 58.5%to 80.4%.The proposed equivalent loading method provides a solution for the rapid and reliable development of occupant protection systems. 展开更多
关键词 Armored vehicles Local model Equivalent loading Dimensionality reduction Bayes optimization
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A new theory for determining large deformation area of roof at intersection and verification analysis
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作者 WU Yi-yi GAO Yu-bing +2 位作者 MA Xiang ZHANG Xing-xing HE Man-chao 《Journal of Central South University》 2025年第2期656-677,共22页
The intersection is a widely used traffic line structure from the shallow tunnel to the deep roadway,and determining the subsidence hidden danger area of the roof is the key to its stability control.However,applying t... The intersection is a widely used traffic line structure from the shallow tunnel to the deep roadway,and determining the subsidence hidden danger area of the roof is the key to its stability control.However,applying traditional maximum equivalent span beam(MESB)theory to determine deformation range,peak point,and angle influence poses a challenge.Considering the overall structure of the intersection roof,the maximum equivalent triangular plate(METP)theory is proposed,and its geometric parameter calculation formula and deflection calculation formula are obtained.The application of the two theories in 18 models with different intersection angles,roadway types,and surrounding rock lithology is verified by numerical analysis.The results show that:1)The METP structure of the intersection roof established by the simulation results of each model successfully determined the location of the roof’s high displacement zone;2)The area comparison method of the METP theory can be reasonably explained:①The roof subsidence of the intersection decreases with the increase of the intersection angle;②The roof subsidence at the intersection of different roadway types has a rectangular type>arch type>circular type;③The roof subsidence of the intersection with weak surrounding rock is significantly larger than that of the intersection with hard surrounding rock.According to the application results of the two theories,the four advantages of the METP theory are compared and clarified in the basic assumptions,mechanical models,main viewpoints,and mechanism analysis.The large deformation inducement of the intersection roof is then explored.The J 2 peak area of the roof drives the large deformation of the area,the peak point of which is consistent with the center of gravity position of the METP.Furthermore,the change in the range of this peak is consistent with the change law of the METP’s area.Hence,this theory clarifies the large deformation area of the intersection roof,which provides a clear guiding basis for its initial support design,mid-term monitoring,and late local reinforcement. 展开更多
关键词 roadway intersection roof deformation equivalent span theory triangular plate structure numerical analysis stress partial tensor
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Experimental and numerical study on external explosions of cylindrical versus spherical charges at tunnel entrance
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作者 Dan Luo Jinsheng Hu +4 位作者 Anbao Wang Xiao Yu Mengmeng Zhang Meili Yao Chun Li 《Defence Technology(防务技术)》 2025年第4期227-243,共17页
Most of the existing studies on tunnel blast wave are based on spherical or grouped charges, however,conventional weapons are mostly cylindrical rather than spherical. In order to analyze the impact of cylindrical cha... Most of the existing studies on tunnel blast wave are based on spherical or grouped charges, however,conventional weapons are mostly cylindrical rather than spherical. In order to analyze the impact of cylindrical charges on the tunnel blast wave loads and to develop a quantitative calculation method, this study carried out experimental and numerical research. Initially, external explosion experiments were conducted using both 35 kg spherical charges and cylindrical charges with aspect ratio of 4.8 at two different distances from the tunnel entrance. Comparative analysis of the blast wave parameters in the tunnel revealed that the explosive equivalent of the cylindrical charges was significantly higher than that of the spherical charges. To address this, an equivalent coefficient κ based on the spherical charges was proposed for the cylindrical charges. Subsequently, numerical simulations were conducted for the experimental conditions, and the numerical simulation results match the experiments well. Through numerical calculations, the reliability of the equivalent coefficient κ under the experimental conditions was verified, and comparison analysis indicated that the explosion energy of cylindrical charges spreads more radially, resulting in more explosion energy entering the tunnel, which is the fundamental reason for the increase in tunnel blast wave loads. Additionally, analyzing the explosion energy ratio entering the tunnel is an effective method for calculating the equivalent coefficient κ. Finally, through more than one hundred sets of numerical calculation results, the impact of the proportional distance λ and the ratio of charge mass to the tunnel cross-section dimension φ on the equivalence coefficients κ was investigated. An empirical formula for the equivalence coefficient κ was derived through fitting, and the accuracy of the formula was validated through literature experimental results. The research findings of this paper will provide valuable guidance for the calculation of blast wave loads in tunnel. 展开更多
关键词 Cylindrical charges Tunnel blast wave Equivalent coefficient Empirical formula Experiment and numerical simulation
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An optimized run-length based algorithm for sparse remote sensing image labeling 被引量:1
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作者 Shen-shen Luan Bo-wen Cheng +3 位作者 Shuai Jiang Yu-hang Wu Zong-ling Li Ji-yang Yu 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2022年第4期663-677,共15页
Labeling of the connected components is the key operation of the target recognition and segmentation in remote sensing images.The conventional connected-component labeling(CCL) algorithms for ordinary optical images a... Labeling of the connected components is the key operation of the target recognition and segmentation in remote sensing images.The conventional connected-component labeling(CCL) algorithms for ordinary optical images are considered time-consuming in processing the remote sensing images because of the larger size.A dynamic run-length based CCL algorithm(Dy RLC) is proposed in this paper for the large size,big granularity sparse remote sensing image,such as space debris images and ship images.In addition,the equivalence matrix method is proposed to help design the pre-processing method to accelerate the equivalence labels resolving.The result shows our algorithm outperforms 22.86% on execution time than the other algorithms in space debris image dataset.The proposed algorithm also can be implemented on the field programming logical array(FPGA) to enable the realization of the real-time processing on-board. 展开更多
关键词 Connected-component labeling Label equivalence resolving Hardware implementation equivalence matrix On-board processing
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翻译中实现社会语用等效(英文)
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作者 赵蓉 《思想战线》 CSSCI 北大核心 2011年第S2期278-279,共2页
As a medium between two different languages, between peoples of two countries, translation is not only a matter of language, but also of cross-cultural transference. According to Professor He Ziran, socio-pragmatic tr... As a medium between two different languages, between peoples of two countries, translation is not only a matter of language, but also of cross-cultural transference. According to Professor He Ziran, socio-pragmatic translation is the kind of translation which examines the conditions on language use that stem from the social and cultural situations to serve cross-cultural communication. This paper focuses on the ways used to achieve socio-pragmatic equivalence in translation practice. 展开更多
关键词 socio-pragmatic equivalence culture-specific EXPRESSIONS SYNONYMS adaptation ANNOTATION
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受潮过程中复合绝缘子的有效附盐密度研究 被引量:8
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作者 梁曦东 仵超 +3 位作者 姚一鸣 高岩峰 王家福 刘瑛岩 《中国电机工程学报》 EI CSCD 北大核心 2015年第21期5632-5640,共9页
硅橡胶复合绝缘子的憎水性迁移特性使其污层具有憎水性,污层中盐分的溶出和流失过程都变得复杂。绝缘子的污闪特性与表面污层受潮时溶解并参与导电的盐分紧密相关,对有效附盐密度(effective equivalent salt deposit density,EESDD,标... 硅橡胶复合绝缘子的憎水性迁移特性使其污层具有憎水性,污层中盐分的溶出和流失过程都变得复杂。绝缘子的污闪特性与表面污层受潮时溶解并参与导电的盐分紧密相关,对有效附盐密度(effective equivalent salt deposit density,EESDD,标记为ρEESDD)进行了更深入的研究。用溶出盐密减去流失盐密来表征有效附盐密度,通过试验研究了憎水性迁移时间和绝缘子表面灰密对ρEESDD的影响,以及自然积污绝缘子受潮过程中的ρEESDD。结果发现:绝缘子受潮时ρEESDD先增大后减小,最终趋于稳定;污层憎水性导致受潮时有效附盐密度的变化过程持续时间更长;灰密的增大会导致有效附盐密度的最大值更晚出现;自然积污绝缘子ρEESDD的最大值仅为污层总等值盐密的15%,说明较低的等值盐密也是复合绝缘子污闪电压高的原因之一。 展开更多
关键词 硅橡胶绝缘子 有效附盐密度(effective EQUIVALENT SALT DEPOSIT density EESDD) 受潮 盐分溶出 盐分流失
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可消半模的正合列 被引量:2
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作者 敖忠平 陈培慈 蔡述平 《江西师范大学学报(自然科学版)》 CAS 北大核心 2008年第6期702-704,共3页
设A和B是S-半模,f:A→B是半模同态.ΔA和Kf分别定义为ΔA={(a,b)∈A×A|a+m=b+m,存在m∈A}和Kf={(a,b)∈A×A|f(a)+m=f(b)+m,存在m∈B}.将Kf和ΔA同时缩小为所规定的Kerf和ΔA,重新给出了monic和epic不同的定义,从不同的角度对... 设A和B是S-半模,f:A→B是半模同态.ΔA和Kf分别定义为ΔA={(a,b)∈A×A|a+m=b+m,存在m∈A}和Kf={(a,b)∈A×A|f(a)+m=f(b)+m,存在m∈B}.将Kf和ΔA同时缩小为所规定的Kerf和ΔA,重新给出了monic和epic不同的定义,从不同的角度对某类特殊的半模—可消半模的正合列进行了刻画. 展开更多
关键词 可消半模 正合列 monic EPIC equivalance
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重庆雪玉洞氡浓度变化特征及其危害防护 被引量:1
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作者 杨晓霞 子涛 +2 位作者 陈炳清 向旭 王晓晓 《中国岩溶》 CAS CSCD 2013年第4期472-479,共8页
利用PRM-2100氡子体监测仪对重庆市丰都县雪玉洞氡子体平衡当量浓度进行连续12个月的监测。研究表明:(1)雪玉洞洞内氡子体平均平衡当量浓度为2 135.7Bq/m3;取平衡因子为0.5,则其平均氡浓度为4 271.4Bq/m3;(2)氡子体平衡当量浓度总体呈... 利用PRM-2100氡子体监测仪对重庆市丰都县雪玉洞氡子体平衡当量浓度进行连续12个月的监测。研究表明:(1)雪玉洞洞内氡子体平均平衡当量浓度为2 135.7Bq/m3;取平衡因子为0.5,则其平均氡浓度为4 271.4Bq/m3;(2)氡子体平衡当量浓度总体呈现出夏季高、冬季低及洞层越高,浓度越高的特点,而且氡子体平衡当量浓度变化与洞内温度变化相关性不明显,但与洞外的相关性则较强;(3)雪玉洞游客因吸入氡子体所致的年均有效剂量当量为0.02mSv/a,只是联合国原子辐射效应科学委员会(UNSCEAR)估计的氡子体对公众产生危害的年有效剂量界限值(1.30mSv/a)的1.54%,因此短时间游览对游客的健康不会产生影响。但是,由于洞穴讲解员、保安、拍照人员在洞内工作时间较长,接受氡子体照射的年均有效剂量当量分别为7.69mSv/a、11.96mSv/a、59.48mSv/a,均高于UNSCEAR的年有效剂量。因此,需要合理安排洞穴内工作人员工作时间和科学地制订出他们的年工作时间上限;加强氡危害相关知识的普及与洞穴工作人员的个人防护;在高氡浓度析出区域进行屏蔽防护或在适当位置安装空气净化器;与此同时,还要加强氡及其子体浓度的分析和监测等。 展开更多
关键词 氡子体 平衡当量浓度 变化特征 防护 重庆雪玉洞 equivalently EFFECTIVE concentration(EECRn )
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