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Porosity and Pore Networks in Tight Dolostone—Mudstone Reservoirs:Insights from the Devonian Three Forks Formation,Williston Basin,USA 被引量:2
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作者 Adedoyin Adeyilola Stephan Nordeng Qinhong Hu 《Journal of Earth Science》 SCIE CAS CSCD 2022年第2期462-481,共20页
This study was performed to evaluate pore systems of reservoir lithofacies within the Devonian Three Forks Formation in the Williston Basin through micro-scale pore characterization.These lithofacies are from the Uppe... This study was performed to evaluate pore systems of reservoir lithofacies within the Devonian Three Forks Formation in the Williston Basin through micro-scale pore characterization.These lithofacies are from the Upper Three Forks section,which is a prominent drilling target within the BakkenThree Forks Petroleum System.Samples from the Formation were examined by(1)physical core description,(2)petrographic thin section microscopy,(3)x-ray diffractometry(XRD)minerals analysis,(4)scanning electron microscopy(SEM),and(5)porosity measurements from helium porosimetry,nuclear magnetic resonance(NMR),gas adsorption and mercury intrusion porosimetry(MIP).These were done to provide better understanding of the local variations in pore structures and how such structures impact reservoir quality within the Three Forks Formation.Seven reservoir lithofacies were identified and described,including laminated lithofacies,massive dolostone,mottled dolostone,massive mudstone,mottled mudstone,mudstone conglomerates,and brecciated mudstone.Samples show a diverse variation in mineralogical composition,pore types,porosity,and pore-size distribution.Six types of pores were identified:interparticle,intercrystalline,intracrystalline,vuggy,microfractures,and mudstone microporosity.Dolostone-rich lithofacies have abundant dolomite and less siliciclastic minerals such as quartz,feldspar,and clays.They also have relatively low porosity and generally larger pore size.A general positive trend exists between porosity with clay minerals and feldspar,in contrast to a negative trend with dolomite,and no clear relationship with quartz content.Results from the gas adsorption analysis,NMR and MIP pore-size distribution confirm an abundance of macropores(>50 nm in diameters)in dolostone dominated lithofacies while other lithofacies generally have abundant mesopores(2–50 nm). 展开更多
关键词 DOLOSTONE MUDSTONE POROSITY pores clay minerals dolomite lithofacies bakken-three forks petroleum system petroleum geology
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Design and Development of a Vision-based Hydraulic Operated Mending Machine for Repairing 3W Forks 被引量:1
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作者 Nirode MANAGE Nimali T.MEDAGEDARA 《Instrumentation》 2020年第4期1-10,共10页
Three wheelers(3 Ws)are widely used in low and middle-income countries,particularly in Asia Pacific region as a comparatively cheap method to passenger transportation and goods delivery.The frequent use of 3 Ws in day... Three wheelers(3 Ws)are widely used in low and middle-income countries,particularly in Asia Pacific region as a comparatively cheap method to passenger transportation and goods delivery.The frequent use of 3 Ws in day-to-day activities have caused a large number of accidents causing injuries to their passengers.Less research has been carried out to identify the reasons behind 3 W accidents.The survey carried out prior to this research has identified that the stability control and speed control are the two key factors which the 3 W accidents attributed to.3 W fork is the main mechanical element that controls the balance and the stability of the vehicle.A damaged 3 W fork(a physical damage or a slight deformation)unbalances the 3 W and had been identified as one of the reasons for large number of accidents.Therefore,correctly reforming the damaged fork is of paramount importance,when concerning the safety of the 3 Ws.Traditionally,both heat-treating and cold-working techniques are used in the mending processes.Not only this manual-labor repairing process weakens the strength of the fork,but also the profile produced is inaccurate.This paper discusses a hydraulic operated fork mending machine with an image processing technique to reform the damaged forks in 3 Ws.An image comparator-based imaging technique is used for this machine vision-based visually guided fork repairing process.Three cameras have been used to capture the images from three perpendicular directions.A contour sketch of the original fork(before the deformation occurs)has been compared against the faulty fork,to assist the worker to carry out the repairing process.The preliminary experimentations have shown that the proposed technique can improve the repositioning of the camber angle by repairing the damaged fork. 展开更多
关键词 Three-wheeler Fork Mending Machine Vision Visually Guided Fork Repairing
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VIBRATION MEASUREMENT OF DOUBLE-ENDED TUNING FORKS RESONATOR
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作者 LENG Changlin ZHANG Guoxiong +2 位作者 ZHONG Ying JIANG Chengzhi YU Fusheng 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2006年第1期128-130,共3页
To enhance the coherence and reliability of the double-ended tuning fork(DETF)resonator,a measurement system of resonator vibration is presented to check its dynamic characteristics.Laser Doppler techniques are utiliz... To enhance the coherence and reliability of the double-ended tuning fork(DETF)resonator,a measurement system of resonator vibration is presented to check its dynamic characteristics.Laser Doppler techniques are utilized and the relation between DETF vibration velocity and output current of photodetector is obtained.Resonator vibration equation is also analyzed and its driving power only depends on the direct current bias voltage and the amplitude of alternative voltage.Furthermore,a special resonator driving control circuit based on measurement is designed.The amplitude and frequency of circuit is controlled by a computer so that highly stable and strong driving signal can be output.Experiments on driving and measuring double-ended tuning fork have been done,The frequency of driving signal is 8 kHz and the peak-to-peak value of driving voltage is 140 V.Experimental results indicate resonator can be drived stably by driving control circuit and dynamic characteristics of DETF may be measured in real time. 展开更多
关键词 RESONATOR Optical measurement Tuning fork MEMS Laser doppler
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Fast step heterodyne light-induced thermoelastic spectroscopy gas sensing based on a quartz tuning fork with high-frequency of 100 kHz
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作者 Yuanzhi Wang Ying He +4 位作者 Shunda Qiao Xiaonan Liu Chu Zhang Xiaoming Duan Yufei Ma 《Opto-Electronic Advances》 2026年第1期36-48,共13页
In this paper,a fast step heterodyne light-induced thermoelastic spectroscopy(SH-LITES)sensor using a high-frequency quartz tuning fork(QTF)with resonant frequency of~100 kHz is reported for the first time.The theoret... In this paper,a fast step heterodyne light-induced thermoelastic spectroscopy(SH-LITES)sensor using a high-frequency quartz tuning fork(QTF)with resonant frequency of~100 kHz is reported for the first time.The theoretical principle of heterodyne LITES(H-LITES)signal generation is analyzed firstly,and an acetylene(C_(2)H_(2))H-LITES sensor is established to verify its performance.Experimental comparisons between the high-frequency QTF and a standard commercial QTF with resonant frequency of~32.768 kHz reveal that the high-frequency QTF exhibits a tenfold faster response time.Specifically,the H-LITES sensor with this QTF achieves a 33 ms measurement cycle,90%shorter than commercial counterparts.Furthermore,The SH-LITES technique is proposed to further shorten the scanning time to 15 ms,which achieves the shortest LITES measurement time known to date.To demonstrate its advantages in dynamic gas detection,an H_(2)O-LITES system integrating both QTF types is constructed for real-time monitoring of H_(2)O concentration during different respiration patterns.Comparative measurements show that the SH-LITES more accurately captures dynamic H_(2)O concentration fluctuations during respiration,outperforming the commercial QTF-based H-LITES sensor in rapid response scenarios. 展开更多
关键词 fast heterodyne light-induced thermoelastic spectroscopy(H-LITES) high-frequency quartz tuning fork(QTF) step heterodyne light-induced thermoelastic spectroscopy(SH-LITES) respiration detection
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Highly sensitive laser spectroscopy sensing based on a novel four-prong quartz tuning fork 被引量:1
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作者 Runqiu Wang Shunda Qiao +1 位作者 Ying He Yufei Ma 《Opto-Electronic Advances》 2025年第4期6-16,共11页
In this paper,a novel four-prong quartz tuning fork(QTF)was designed with enlarged deformation area,large prong gap,and low resonant frequency to improve its performance in laser spectroscopy sensing.A theoretical sim... In this paper,a novel four-prong quartz tuning fork(QTF)was designed with enlarged deformation area,large prong gap,and low resonant frequency to improve its performance in laser spectroscopy sensing.A theoretical simulation model was established to optimize the design of the QTF structure.In the simulation of quartz-enhanced photoacoustic spectroscopy(QEPAS)technology,the maximum stress and the surface charge density of the four-prong QTF demonstrated increases of 11.1-fold and 15.9-fold,respectively,compared to that of the standard two-prong QTF.In the simulation of light-induced thermoelastic spectroscopy(LITES)technology,the surface temperature difference of the four-prong QTF was found to be 11.4 times greater than that of the standard QTF.Experimental results indicated that the C_(2)H_(2)-QEPAS system based on this innovative design improved the signal-to-noise-ratio(SNR)by 4.67 times compared with the standard QTF-based system,and the SNR could increase up to 147.72 times when the four-prong QTF was equipped with its optimal acoustic micro-resonator(AmR).When the average time of the system reached 370 s,the system achieved a MDL as low as 21 ppb.The four-prong QTF-based C_(2)H_(2)-LITES system exhibited a SNR improvement by a factor of 4.52,and a MDL of 96 ppb was obtained when the average time of the system reached 100 s.The theoretical and experimental results effectively demonstrated the superiority of the four-prong QTF in the field of laser spectroscopy sensing. 展开更多
关键词 four-prong quartz tuning fork C2H2 detection quartz-enhanced photoacoustic spectroscopy light-induced thermoelastic spectroscopy
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基于Fork/Join模式的模幂算法并行化实现
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作者 张翔 《计算机应用文摘》 2025年第20期244-246,249,共4页
公钥加密与数字签名算法普遍依赖于模幂运算,而大整数模幂运算的核心瓶颈在于高计算复杂度的乘法与幂运算.在现有研究基础上,文章系统分析了二元法、Karatsuba算法及快速傅里叶变换(FFT)在模幂运算中的应用特点,并针对其计算效率与资源... 公钥加密与数字签名算法普遍依赖于模幂运算,而大整数模幂运算的核心瓶颈在于高计算复杂度的乘法与幂运算.在现有研究基础上,文章系统分析了二元法、Karatsuba算法及快速傅里叶变换(FFT)在模幂运算中的应用特点,并针对其计算效率与资源消耗进行了相应优化.进一步地,基于Java语言环境,采用多线程Fork/Join框架实现改进算法,以提升并行计算性能与整体运算效率. 展开更多
关键词 模幂 Karatsuba FFT JAVA Fork/Join
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One-step quartz-MEMS micro-fabrication strategy for a grooved tuning fork
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作者 Yide Dong Chunyan Yin +1 位作者 Guangbin Dou Litao Sun 《Nanotechnology and Precision Engineering》 2025年第3期117-130,共14页
Grooved tuning forks with hierarchical structures have become some of the most widely used piezoelectric quartz microelectromechanical system devices;however,fabricating these devices requires multi-step processes due... Grooved tuning forks with hierarchical structures have become some of the most widely used piezoelectric quartz microelectromechanical system devices;however,fabricating these devices requires multi-step processes due to the complexity of etching of quartz,particularly in specific orientations of the crystal lattice.This paper proposes a one-step fabrication strategy that can form a complete hierarchical structure with only a single etching process using novel lithography patterns.The core principle of this strategy is based on the effect of the size of the groove patterns on quartz etching,whereby trenches of varying depths can be created in a fixed etching time by adjusting the width of the hard mask.Specifically,the device outline and grooved structure can be completed using a seamlessly designed etching pattern and optimized time.Furthermore,the etching structure itself influences the etching results.It was found that dividing a wide trench by including a wall to separate it into two narrow trenches significantly reduces the etching rate,allowing for predictable tuning of the etching rate for wider grooves.This effectively increases the usability and flexibility of the one-step strategy.This was applied to the manufacture of an ultra-small quartz grooved tuning fork resonator with a frequency of 32.768 kHz in a single step,increasing production efficiency by almost 45%and reducing costs by almost 30%compared to current methods.This has great potential for improving the productivity of grooved tuning fork devices.It can also be extended to the fabrication of other quartz crystal devices requiring hierarchical structures. 展开更多
关键词 Quartz crystal Quartz MEMS MICROFABRICATION Grooved tuning fork
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Photoacoustic spectroscopy and light-induced thermoelastic spectroscopy based on invertedtriangular lithium niobate tuning fork
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作者 Junjie Mu Guowei Han +3 位作者 Runqiu Wang Shunda Qiao Ying He Yufei Ma 《Opto-Electronic Science》 2025年第12期62-72,共11页
In this paper,a novel self-designed inverted-triangular lithium niobate tuning fork(LiNTF)was used to construct gas sensing system for the first time.The optimal ratio of the upper and lower boundaries of the inverted... In this paper,a novel self-designed inverted-triangular lithium niobate tuning fork(LiNTF)was used to construct gas sensing system for the first time.The optimal ratio of the upper and lower boundaries of the inverted-triangular LiNTF is found by scanning through finite element analysis(FEA).The surface charge density and stress value of the inverted-triangular LiNTF are both higher than those of the standard quartz tuning fork(QTF).In the lithium niobate-enhanced photoacoustic spectroscopy(LiNPAS)sensing system,the 2f peak and signal-to-noise ratio(SNR)of the inverted-triangular LiNTF are 7.41 times and 5.89 times those of the standard QTF,respectively.After forming acoustic standing wave field with the acoustic micro-resonator(AmR),the LiNPAS system achieves an SNR 56.16 times higher than without the AmR.Based on Allan variance analysis,the system achieves a minimum detection limit(MDL)of 7.25 ppb with an averaging time of 800 seconds.In the light-induced thermoelastic spectroscopy(LITES)sensing system,the 2f peak and SNR of the inverted-triangular LiNTF are 7.82 times and 6.03 times those of the standard QTF,respectively.When the averaging time reaches 100 s,the MDL of the system is found to be 25.78 ppb. 展开更多
关键词 lithium niobate tuning fork lithium niobate-enhanced photoacoustic spectroscopy light-induced thermoelastic spectroscopy C_(2)H_(2)detection
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祁连山区冰沟流域积雪分布特征及其属性观测分析 被引量:36
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作者 郝晓华 王建 +6 位作者 车涛 张璞 梁继 李弘毅 李哲 白云洁 白艳芬 《冰川冻土》 CSCD 北大核心 2009年第2期284-292,共9页
以祁连山冰沟流域为研究区,通过在流域内布设花杆观测积雪深度,调查了山区积雪分布情况;利用雪特性分析仪测量了区内积雪密度、介电常数、液态水含量等积雪参数,光谱仪测量了不同类型积雪的光谱特征,手持反照率测量计观测积雪表面反照率... 以祁连山冰沟流域为研究区,通过在流域内布设花杆观测积雪深度,调查了山区积雪分布情况;利用雪特性分析仪测量了区内积雪密度、介电常数、液态水含量等积雪参数,光谱仪测量了不同类型积雪的光谱特征,手持反照率测量计观测积雪表面反照率,带刻度手持放大镜测量积雪粒径,红外温度计和针式温度计测量雪层的温度和实地测量积雪属性.同时,在研究区内选择加强观测区挖雪坑,对雪层内部属性和雪剖面分层特性作了进一步研究,计算了流域内积雪等效密度;最后对试验中所使用的野外实测积雪的各种方法进行了评价.研究表明:山区积雪分布很不均匀,在阴坡山谷雪深最深,阳坡雪积累最少,即使在同一样区,积雪分布也不均匀;研究区的积雪属于潮雪,体积含水量在3%以下;不同粒径、类型和表面粗糙度的积雪反射率不同,验证了积雪光谱是雪颗粒、污染物和地面粗糙度的函数;积雪反照率随太阳高度角升高逐步降低,在没有新降雪的情况下,日反照率也逐渐降低;雪分层比较明显,雪下冰晶层发育良好.当深度达到20 cm时,积雪具有保温作用;冰沟流域的积雪等效密度随时间和空间变化不大,经计算为0.16 g.cm-3. 展开更多
关键词 冰沟流域 积雪分布特征 积雪属性 SNOW FORK 积雪等效密度
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阿尔泰山融雪期不同下垫面积雪特性观测与分析研究 被引量:26
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作者 张伟 沈永平 +4 位作者 贺建桥 贺斌 努尔兰.哈再孜 吴雪娇 王国亚 《冰川冻土》 CSCD 北大核心 2014年第3期491-499,共9页
2014年3月融雪期间在阿尔泰山额尔齐斯河河源区,基于已有的气象和积雪(雪深、雪密度)观测,利用Snow Fork雪特性仪和便携式温度计TP3001,选择草地、水泥地和河冰三种不同的下垫面分别观测了分层积雪密度、液态水含量和雪层温度变化.结果... 2014年3月融雪期间在阿尔泰山额尔齐斯河河源区,基于已有的气象和积雪(雪深、雪密度)观测,利用Snow Fork雪特性仪和便携式温度计TP3001,选择草地、水泥地和河冰三种不同的下垫面分别观测了分层积雪密度、液态水含量和雪层温度变化.结果表明:三种下垫面上表层积雪的温度、液态水含量和密度变化规律基本一致.积雪特性的差异主要体现在积雪层底部,河冰和草地与积雪接触面温度日变化过程呈现出"单峰型",而与水泥地接触面上的温度日变化呈现出"双峰型";河冰上积雪底部的液态水含量最小且日变化幅度较小,草地次之,水泥上积雪底部液态水含量的波动最大;水泥和草地上底部积雪的密度变化趋势一致,为密实化过程,而河冰上积雪底部的积雪因深霜层的形成致使雪密度逐渐减小.对同一下垫面上的积雪而言,水泥和草地上积雪温度的极大值出现在雪层中间,河冰上雪层的温度廓线沿雪深有波动上升的趋势,最大值出现在积雪与河冰的接触面处.三种下垫面上积雪的液态水含量最大值均出现在中间雪层,雪密度均呈现沿雪深增加而递减的变化趋势.液态水含量受积雪温度的控制,当积雪温度低于-3℃时,积雪中的液态水可以忽略不计;当积雪温度低于-1℃时,积雪的液态水含量低于1%;当积雪温度大于-1℃时,积雪中出现液态水的比例显著增加,且液态水含量的波动范围较大,最高可到6.2%. 展开更多
关键词 阿尔泰山 季节性积雪 雪密度 液态水含量 积雪温度 Snow FORK
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大规模电力系统潮流转移比多核并行批处理方法 被引量:9
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作者 罗彬 李刚 +3 位作者 苗树敏 程春田 吴琛 王森 《中国电机工程学报》 EI CSCD 北大核心 2015年第21期5446-5454,共9页
实现各类预想故障下潮流转移比快速仿真分析是电网安全稳定运行的重要保证。针对现有实际运行方式中潮流转移分析困难问题,提出大规模电力系统潮流转移比多核并行批处理方法。该方法基于广泛使用的商业大系统分析工具,在参数解析分类、... 实现各类预想故障下潮流转移比快速仿真分析是电网安全稳定运行的重要保证。针对现有实际运行方式中潮流转移分析困难问题,提出大规模电力系统潮流转移比多核并行批处理方法。该方法基于广泛使用的商业大系统分析工具,在参数解析分类、故障自动设置及结果解析的基础上,引入深度优先搜索(depth first search,DFS)算法进行孤立节点和孤岛区域检测以保证网络完整性,结合潮流计算合理性的自动判别以实现潮流转移比的批处理分析;同时在多核环境下,构建基于Fork/Join的并行框架,采用"分治模式"递归分解计算任务,从而实现分析方法的多核并行。算例仿真和在云南电网的实际应用验证了所提方法的有效性和快速性。 展开更多
关键词 潮流转移 深度优先搜索 多核并行 Fork/Join框架 PSD-BPA
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基于任务复制的调度算法 被引量:10
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作者 张建军 李庆华 瞿勇 《计算机工程与设计》 CSCD 北大核心 2009年第8期1896-1899,2029,共5页
任务调度是并行分布式计算系统中最具挑战性的NP完全问题之一。基于任务复制的调度是一种有效的调度方法。在通信开销较小的情况下,现已有许多算法能产生最优调度。但其最优条件要么比较苛刻,要么比较复杂。因此,针对这些算法存在的问题... 任务调度是并行分布式计算系统中最具挑战性的NP完全问题之一。基于任务复制的调度是一种有效的调度方法。在通信开销较小的情况下,现已有许多算法能产生最优调度。但其最优条件要么比较苛刻,要么比较复杂。因此,针对这些算法存在的问题,提出一个新的基于任务复制的聚集调度(TDCS)算法,不仅其最优条件简单、宽松,而且该算法具有更小的时间复杂度O(log),其中,和分别表示任务集中任务的个数和最大入度。 展开更多
关键词 最优调度算法 任务复制 最优条件 任务聚集 Fork—Join任务图
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调度Fork-Join任务图的贪心算法 被引量:6
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作者 杨斌 张建军 杨峰 《计算机工程与设计》 CSCD 北大核心 2008年第15期3864-3866,3894,共4页
任务调度算法的目标是把组成并行程序的一组任务分配到多个处理器以使得程序的完成时间最短,这是一个NP完全问题。虽然许多算法在任务满足某些条件时能产生最优调度,但大多都忽略了节省处理器个数和最小化程序总的完成时间等问题。Fork-... 任务调度算法的目标是把组成并行程序的一组任务分配到多个处理器以使得程序的完成时间最短,这是一个NP完全问题。虽然许多算法在任务满足某些条件时能产生最优调度,但大多都忽略了节省处理器个数和最小化程序总的完成时间等问题。Fork-Join结构是一种并行处理的基本结构。因此,专门针对Fork-Join任务图,提出了一个能产生最优调度的新的贪心调度算法,该算法具有高的加速比和总体效率,时间复杂度为2,其中,表示任务集中任务的个数。实验结果表明,相比其它算法,该算法具有较短的调度长度、较短的完成时间,使用的处理器数较少。 展开更多
关键词 最优调度算法 任务复制 Fork—Join任务图 关键任务 加速比
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Forking引理与一类基于身份签名体制的安全性证明(英文) 被引量:4
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作者 顾纯祥 祝跃飞 潘晓豫 《软件学报》 EI CSCD 北大核心 2007年第4期1007-1014,共8页
在随机谕示模型下,研究一类基于身份的签名体制(称为基于身份的一般签名体制)的安全性.所得理论成果可以被看作Pointcheval和Stern提出的Forking引理在基于身份签名体制研究领域的扩展,有助于理解和简化一些现有的基于身份签名体制的安... 在随机谕示模型下,研究一类基于身份的签名体制(称为基于身份的一般签名体制)的安全性.所得理论成果可以被看作Pointcheval和Stern提出的Forking引理在基于身份签名体制研究领域的扩展,有助于理解和简化一些现有的基于身份签名体制的安全性证明,如Cha-Cheon的体制、Hess的体制1及Cheon-Kim-Yoon的体制等. 展开更多
关键词 基于身份的签名 Forking引理 可证安全 存在性伪造
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Homologous recombination in DNA repair and DNA damage tolerance 被引量:35
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作者 Xuan Li Wolf-Dietrich Heyer 《Cell Research》 SCIE CAS CSCD 2008年第1期99-113,共15页
Homologous recombination (HR) comprises a series of interrelated pathways that function in the repair of DNA double-stranded breaks (DSBs) and interstrand crosslinks (ICLs). In addition, recombination provides c... Homologous recombination (HR) comprises a series of interrelated pathways that function in the repair of DNA double-stranded breaks (DSBs) and interstrand crosslinks (ICLs). In addition, recombination provides critical support for DNA replication in the recovery of stalled or broken replication forks, contributing to tolerance of DNA damage. A central core of proteins, most critically the RecA homolog Rad51, catalyzes the key reactions that typify HR: homology search and DNA strand invasion. The diverse functions of recombination are reflected in the need for context-specific factors that perform supplemental functions in conjunction with the core proteins. The inability to properly repair complex DNA damage and resolve DNA replication stress leads to genomic instability and contributes to cancer etiology. Mutations in the BRCA2 recombination gene cause predisposition to breast and ovarian cancer as well as Fanconi anemia, a cancer predisposition syndrome characterized by a defect in the repair of DNA interstrand crosslinks. The cellular functions of recombination are also germane to DNA-based treatment modalities of cancer, which target replicating cells by the direct or indirect induction of DNA lesions that are substrates for recombination pathways. This review focuses on mechanistic aspects of HR relating to DSB and ICL repair as well as replication fork support. 展开更多
关键词 DNA repair double-strand breaks genome stability homologous recombination interstrand crosslinks stalled replication forks
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Dalvik虚拟机进程模型分析 被引量:18
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作者 周毅敏 陈榕 《计算机技术与发展》 2010年第2期83-86,共4页
Android手机操作系统是Google于2008年推出的智能手机操作系统,它的所有应用都是基于Java语言的,它的类Java虚拟机Dalvik提供了所有应用的运行时环境。Dalvik是一个面向Linux作为嵌入式操作系统设计的虚拟机,尤其是它的面向进程的设计,... Android手机操作系统是Google于2008年推出的智能手机操作系统,它的所有应用都是基于Java语言的,它的类Java虚拟机Dalvik提供了所有应用的运行时环境。Dalvik是一个面向Linux作为嵌入式操作系统设计的虚拟机,尤其是它的面向进程的设计,充分利用了Linux进程管理的特点。介绍了Dalvik所依赖的基础,即Linux操作系统内核中进程管理的一些特性和传统Java程序对进程的控制;进而论述了Dalvik的进程模型的特点,从API和本地代码两个层面具体阐述了进程运行、创建和之间通信的部分细节。文中旨在为Dalvik的研究和应用提供参考。 展开更多
关键词 Dalvik 虚拟机 结合子 FORK 写时复制
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面向Fork/Join框架的软件重构及性能分析 被引量:2
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作者 张冬雯 柳晨光 张杨 《计算机应用》 CSCD 北大核心 2015年第11期3172-3177,共6页
针对目前对于Fork/Join框架应用和性能分析的相关工作还不多的现状,以JGF基准测试程序套件为基础,对其中的series、crypt、sparsematmult和sor等程序使用Fork/Join框架进行重构,并以series程序为例,详细地说明了重构的过程。在实验中,首... 针对目前对于Fork/Join框架应用和性能分析的相关工作还不多的现状,以JGF基准测试程序套件为基础,对其中的series、crypt、sparsematmult和sor等程序使用Fork/Join框架进行重构,并以series程序为例,详细地说明了重构的过程。在实验中,首先,测试了每个程序在不同阈值下使用Fork/Join框架分别递归1、2、3次执行程序的时间,进而选择相对较好的阈值;然后,对每个程序使用Fork/Join框架和使用Thread的执行时间进行了对比;此外,测试了重构后的程序在执行过程中任务窃取的情况。实验结果表明,Fork/Join框架执行时间与多线程执行时间相比,平均降低了14.2%;对于series程序,当数据大小为size C且线程个数为2时,Fork/Join框架执行时间比多线程执行时间降低高达40%,可见,在多核处理器平台上应用Fork/Join框架比使用多线程将获得更好的性能。 展开更多
关键词 Fork/Join框架 软件重构 工作窃取 性能分析
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Finite Element Simulation of the Vibratory Characteristics for Quartz Tuning Fork Gyroscope 被引量:2
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作者 王莹 孙雨南 秦秉坤 《Journal of Beijing Institute of Technology》 EI CAS 2002年第2期155-158,共4页
The micro quartz crystal tuning fork gyroscope is a new type of vibratory gyroscope. The gyroscope should be analyzed and simulated early in the design stage in order to offer reliable basis for design and to shorten ... The micro quartz crystal tuning fork gyroscope is a new type of vibratory gyroscope. The gyroscope should be analyzed and simulated early in the design stage in order to offer reliable basis for design and to shorten the period of development. Thus the vibratory characteristics of the gyroscope is simulated with the finite element method of coupled field. The optimum exciting frequency and the factors which influence the gyroscope sensitivity are determined. The method for adjusting the frequency deviation between driving and detecting modes is also proposed. 展开更多
关键词 quartz gyroscope tuning fork finite element method
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LL-Ⅲ模型在美国Baron Fork流域的应用 被引量:1
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作者 赵英虎 李兰 +2 位作者 周浩澜 杨超 武见 《人民长江》 北大核心 2008年第6期46-48,共3页
有物理基础的流域分布式水文模型对流域产汇流以及对洪水过程的模拟与预报一直是水文研究的重点。分析了美国Baron Fork流域的降雨产汇流特性,应用基于DEM的LL-Ⅲ水文模型对Baron Fork流域进行产汇流模拟及洪水预报,结果表明,从模型模... 有物理基础的流域分布式水文模型对流域产汇流以及对洪水过程的模拟与预报一直是水文研究的重点。分析了美国Baron Fork流域的降雨产汇流特性,应用基于DEM的LL-Ⅲ水文模型对Baron Fork流域进行产汇流模拟及洪水预报,结果表明,从模型模拟精度来看,该水文模型在Baron Fork流域洪水预报、流量模拟应用中取得了较好的效果,可以在水文、地质、地貌、气候等方面与该地区类似的流域推广。 展开更多
关键词 流域数字化 DEM水文分析 分布式水文模型 Baron FORK
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广义Fork-Join任务图的调度问题研究 被引量:2
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作者 杨峰 张建军 《兵工自动化》 2009年第12期37-40,共4页
Fork-Join结构是一种并行处理的基本结构。为处理传统方法难以解决的复杂和非线性问题,缩短整个程序的总完成时间,针对广义Fork-Join任务图提出了基于遗传算法的调度算法,该算法将遗传算法和任务复制相结合,有效地缩短了得到最优结果的... Fork-Join结构是一种并行处理的基本结构。为处理传统方法难以解决的复杂和非线性问题,缩短整个程序的总完成时间,针对广义Fork-Join任务图提出了基于遗传算法的调度算法,该算法将遗传算法和任务复制相结合,有效地缩短了得到最优结果的时间。实验结果表明,与其他算法相比,该算法具有较短的调度长度。 展开更多
关键词 任务调度 任务复制 遗传算法 广义Fork—Join任务图
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