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Real-Time PCR Technique and Its Application in Quantification of Plant Nucleic Acid Molecules 被引量:8
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作者 刘进元 《Acta Botanica Sinica》 CSCD 2003年第6期631-637,共7页
Real-time PCR is a closed DNA amplification system that skillfully integrates biochemical, photoelectric and computer techniques. Fluorescence data acquired once per cycle provides rapid absolute quantification of ini... Real-time PCR is a closed DNA amplification system that skillfully integrates biochemical, photoelectric and computer techniques. Fluorescence data acquired once per cycle provides rapid absolute quantification of initial template copy numbers as PCR products are generated. This technique significantly simplifies and accelerates the process of producing reproducible quantification of nucleic acid molecules. It not only is a sensitive, accurate and rapid quantitative method, but it also provides an easier way to calculate the absolute starting copy number of nucleic acid molecules to be tested. Together with molecular bio-techniques, like microarray, real-time PCR will play a very important role in many aspects of molecular life science such as functional gene analysis and disease molecular diagnostics. This review introduces the detailed principles and application of the real-time PCR technique, describes a recently developed system for exact quantification of AUX/IAA genes In Arabidopsis, and discusses the problems with the real-time PCR process. 展开更多
关键词 real-time PCR technique quantification of plant nucleic acid molecules gene expression molecular medicine
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Comparative study on efficacy of three sperm-separation techniques 被引量:3
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作者 LanXU Ren-KangLU +1 位作者 LingCHEN Yan-LuanZHENG 《Asian Journal of Andrology》 SCIE CAS CSCD 2000年第2期131-134,共4页
Aim: To evaluate the comparative effectiveness of real-time sperm separation technique (Wang's tube method) andother two conventional methods in isolating high-quality sperm preparation, and to compare the spouse ... Aim: To evaluate the comparative effectiveness of real-time sperm separation technique (Wang's tube method) andother two conventional methods in isolating high-quality sperm preparation, and to compare the spouse pregnancy ratein intrauterine insemination (IUI) with sperm preparations isolated by these methods. Methods: The effectivenessof the real-time sperm separation technique, the conventional swim-up and the Percoll discontinuous density gradientmethods in isolating sperm preparations from 60 infertile patients (20 with apparently normal semen and 40, abnormalsemen contaminated with microorganisms and other impurities) was evaluated and compared. The microorganisms to beremoved included bacteria, vires, Chlamydia trachomaticum, Ureaplsama urealyticum, etc. The spouse pregnancyrates in IUI with sperm preparations isolated by these three techniques from 80 oligoasthenoteratospermic patients werealso compared. Results: The quality (including the percentages of normal form, normal-chromatin and motilesperm, and the grade of motility) of sperm obtained by the real-time sperm separation technique was much higher ( P< 0.01) as compared with those by the other two methods. The Wang's tube method was also more effective in remov-ing microorganisms and other impurities. The method provided a higher IUI pregnancy rate than the other two spermseparation techniques ( P < 0.05). Conclusion: The real-time sperm separation technique is the most effectivemethod so far available in isolating high-quality sperm samples to be used in assisted reproduction. 展开更多
关键词 techmiques real-time sperm separation technique swim-up method Percoll gradient method Wang's tube REPRODUCTION
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Clinical significance and influencing factors of linked color imaging technique in real-time diagnosis of active Helicobacter pylori infection 被引量:12
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作者 Li Wang Xiang-Chun Lin +7 位作者 Hai-Long Li Xue-Song Yang Lei Zhang Xin Li Peng Bai Yan Wang Xue Fan Yi-Ming Ding 《Chinese Medical Journal》 SCIE CAS CSCD 2019年第20期2395-2401,共7页
Background:Determining the Helicobacter pylori (H. pylori) infection state during the gastroscopic process is important but still challenging. The linked color imaging (LCI) technique might emphasize the mucosal color... Background:Determining the Helicobacter pylori (H. pylori) infection state during the gastroscopic process is important but still challenging. The linked color imaging (LCI) technique might emphasize the mucosal color change after H. pylori infection, which might help the diagnosis. In the present study, we aimed to compare the LCI technique with traditional white light imaging (WLI) endoscopy for diagnosing active H. pylori infection.Methods:We collected and analyzed gastroscopic images from 103 patients in our hospital from November 2017 to March 2018, including both LCI and WLI modes. All images were randomly disordered and independently evaluated by four endoscopists who were blinded to the H. pylori status of patients. In addition, the H. pylori state was determined by both rapid urease test and pathology staining. The sensitivity, specificity, positive prediction value (PPV), and negative prediction value (NPV) were calculated for the detection of H. pylori infection. Moreover, the kappa value and interclass correlation coefficient (ICC) were used to evaluate the inter-observer variety by SPSS 24.0 software.Results:Of the 103 enrolled patients, 27 of them were positive for H. pylori infection, while the 76 patients were negative. In total, 388 endoscopic images were selected, including 197 WLI and 191 LCI. The accuracy rate for H. pylori evaluation in the corpus LCI group was significantly higher than other groups (81.2% vs. 64.3%-76.5%, χ2 = 34.852, P < 0.001). Moreover, the corpus LCI group had the optimal diagnostic power with the sensitivity of 85.41% (95% confidence interval [CI]: 76.40%-91.51%), the specificity of 79.71% (95% CI: 74.38%-84.19%), the PPV of 59.42% (95% CI: 50.72%-67.59%), and the NPV of 94.02% (95% CI: 89.95%-96.56%), respectively. The kappa values between different endoscopists were higher with LCI than with WLI (0.433-0.554 vs. 0.331-0.554). Consistently, the ICC value was also higher with LCI than with WLI (0.501 [95% CI: 0.429-0.574] vs. 0.397 [95% CI: 0.323-0.474]). We further analyzed the factors that might lead to misjudgment, revealing that active inflammation might disturb WLI judgment (accuracy rate: 58.70% vs. 76.16%, χ2 = 21.373, P < 0.001). Atrophy and intestinal metaplasia might affect the accuracy of the LCI results (accuracy rate: 66.96% vs. 73.47%, χ2 = 2.027;68.42% vs. 73.53 %, χ2 = 1.594, respectively);however, without statistical significance (P = 0.154 and 0.207, respectively).Conclusions:The application of LCI at the corpus to identify H. pylori infection is reliable and superior to WLI. The inter-observer variability is lower with LCI than with WLI. 展开更多
关键词 HELICOBACTER PYLORI Image ENHANCEMENT technique Linked COLOR imaging real-time diagnosis
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Real-time and dynamic transduction technique for simultaneous detection of O_2 and CO_2
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作者 LIU Wenjun and ZHOU ZhongbaiDepartment of Chemistry, Wuhan University, Wuhan 430072, China 《Chinese Science Bulletin》 SCIE EI CAS 1997年第14期1175-1180,共6页
OXYGEN and carbon dioxide are the coexistent gases closely related to life processes. In our pre-
关键词 real-time and DYNAMIC TRANSDUCTION technique carbon dioxide oxygen MODULATED POTENTIAL PULSE coulometry (MP-PC) MODULATED POTENTIAL PULSE amperometry (MPPA).
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井群出水量减少原因分析及治理——以北京某应急备用地下水源地为例 被引量:4
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作者 查恩来 张秋建 《水文地质工程地质》 CAS CSCD 北大核心 2005年第2期115-117,共3页
近来,为缓解北京市日趋紧张的供水情况,需启用1995年建成的北京某应急备用地下水源地。该水源地建有30眼水井,属第四系河旁非承压含水层,当时静水位埋深为4m,单井平均出水量超过4000m3h。近年来由于各种原因,尤其是2003年该水源井出水... 近来,为缓解北京市日趋紧张的供水情况,需启用1995年建成的北京某应急备用地下水源地。该水源地建有30眼水井,属第四系河旁非承压含水层,当时静水位埋深为4m,单井平均出水量超过4000m3h。近年来由于各种原因,尤其是2003年该水源井出水量大幅减少的主要原因是含铁碳质化合物附着对井壁的堵塞。针对这一情况,通过试验确定了以强力正反冲洗活塞洗井工艺为核心的复合洗井方案,对17眼水井实施洗井处理,使井群出水量恢复到了建井初期的水平,取得了良好的效果。 展开更多
关键词 应急备用水源地 测试分析 附着物 复合洗井技术
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GNSS CV精密时间服务系统的可靠性改进
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作者 林思佳 王玉林 +2 位作者 王平利 卢建福 刘彪 《时间频率学报》 CSCD 2013年第2期84-91,共8页
为了提高中国科学院国家授时中心基于GNSS CV精密时间服务系统的可靠性,提出并采用了主备服务器双机热备的技术方案。阐述了服务器主从模式双机热备的工作模式,包括主、备服务器间的数据备份、服务器运行状态的检测和切换。根据系统中... 为了提高中国科学院国家授时中心基于GNSS CV精密时间服务系统的可靠性,提出并采用了主备服务器双机热备的技术方案。阐述了服务器主从模式双机热备的工作模式,包括主、备服务器间的数据备份、服务器运行状态的检测和切换。根据系统中数据类型和备份要求的不同,采用了相应的备份策略和备份程序实现主备服务器间数据备份;设计了主备服务器的运行状态检测和切换控制流程。测试表明,采用服务器双机热备技术显著提高了GNSS CV精密时间服务系统的可靠性。 展开更多
关键词 GNSS CV 精密时间 双机热备技术 数据备份
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基于半马尔可夫过程的冷备系统维护策略优化 被引量:5
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作者 綦法群 周宏明 +1 位作者 庞继红 徐文杰 《中国机械工程》 EI CAS CSCD 北大核心 2020年第3期336-343,共8页
为了提高系统的可靠性,构建了两机冷备系统,提出了基于半马尔可夫过程的冷备系统预防性维护模型,该模型考虑随机失效、退化失效两种失效形式,采用了小修、大修、预防性维护相结合的维护方式。基于半马尔可夫理论及再生点技术分析了系统... 为了提高系统的可靠性,构建了两机冷备系统,提出了基于半马尔可夫过程的冷备系统预防性维护模型,该模型考虑随机失效、退化失效两种失效形式,采用了小修、大修、预防性维护相结合的维护方式。基于半马尔可夫理论及再生点技术分析了系统运行中的状态变化过程,建立了马尔可夫更新方程组。通过拉普拉斯变换求得系统首次平均失效时间和稳态可用度的函数表达式,并分别以系统首次平均失效时间和稳态可用度为可靠性指标求解最佳预防性维护策略。最后通过实例分析了不同参数变化对系统可靠性及最佳预防性维护周期的影响。实验结果表明,所提出的建模方法对解决冷备系统维护决策具有指导意义。 展开更多
关键词 冷备系统 半马尔可夫过程 再生点技术 预防性维护 维护策略优化
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Multiplex qPCR for serodetection and serotyping of hepatitis viruses: A brief review 被引量:5
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作者 Mohammad Irshad Priyanka Gupta +1 位作者 Dhananjay Singh Mankotia Mohammad Ahmad Ansari 《World Journal of Gastroenterology》 SCIE CAS 2016年第20期4824-4834,共11页
The present review describes the current status of multiplex quantitative real time polymerase chain reaction(q PCR) assays developed and used globally for detection and subtyping of hepatitis viruses in body fluids. ... The present review describes the current status of multiplex quantitative real time polymerase chain reaction(q PCR) assays developed and used globally for detection and subtyping of hepatitis viruses in body fluids. Several studies have reported the use of multiplex q PCR for the detection of hepatitis viruses, including hepatitis A virus(HAV), hepatitis B virus(HBV), hepatitis C virus(HCV), hepatitis D virus(HDV), and hepatitis E virus(HEV). In addition, multiplex q PCR has also been developed for genotyping HBV, HCV, and HEV subtypes. Although a single step multiplex q PCR assay for all six hepatitis viruses, i.e., A to G viruses, is not yet reported, it may be available in the near future as the technologies continue to advance. All studies use a conserved region of the viral genome as the basis of amplification and hydrolysis probes as the preferred chemistries for improved detection. Based on a standard plot prepared using varying concentrations of template and the observed threshold cycle value, it is possible to determine the linear dynamic range and to calculate an exact copy number of virus in the specimen. Advantages of multiplex q PCR assay over singleplex or other molecular techniques in samples from patients with co-infection include fast results, low cost, and a single step investigation process. 展开更多
关键词 CO-INFECTION Viral genome Quantitative real-time polymerase chain reaction Genotyping techniques SEROTYPING Hepatitis viruses
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城域数据网BRAS热备技术和组网方案研究 被引量:2
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作者 陈琛 王宾 杨阳 《邮电设计技术》 2013年第7期72-74,共3页
随着IP技术的飞速发展及城域数据网业务量的剧增,如何提高BRAS的可靠性,已成为重点关注问题。根据BRAS热备技术原理、组网方案研究及现网测试结果,给出了目前BRAS热备推荐方案,保障了各类业务在BRAS上的安全承载,提升了城域数据网的可... 随着IP技术的飞速发展及城域数据网业务量的剧增,如何提高BRAS的可靠性,已成为重点关注问题。根据BRAS热备技术原理、组网方案研究及现网测试结果,给出了目前BRAS热备推荐方案,保障了各类业务在BRAS上的安全承载,提升了城域数据网的可靠性。 展开更多
关键词 城域数据网 BRAS 热备技术 组网方案
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Dorsal root ganglion neurons promote proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells 被引量:4
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作者 Pei-xun Zhang Xiao-rui Jiang +3 位作者 Lei Wang Fang-min Chen Lin Xu Fei Huang 《Neural Regeneration Research》 SCIE CAS CSCD 2015年第1期119-123,共5页
Preliminary animal experiments have confirmed that sensory nerve fibers promote osteoblast differentiation, but motor nerve fibers have no promotion effect. Whether sensory neurons pro- mote the proliferation and oste... Preliminary animal experiments have confirmed that sensory nerve fibers promote osteoblast differentiation, but motor nerve fibers have no promotion effect. Whether sensory neurons pro- mote the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells remains unclear. No results at the cellular level have been reported. In this study, dorsal root ganglion neurons (sensory neurons) from Sprague-Dawley fetal rats were co-cultured with bone marrow mesenchymal stem cells transfected with green fluorescent protein 3 weeks after osteo- genic differentiation in vitro, while osteoblasts derived from bone marrow mesenchymal stem cells served as the control group. The rat dorsal root ganglion neurons promoted the prolifera- tion of bone marrow mesenchymal stem cell-derived osteoblasts at B and 5 days of co-culture, as observed by fluorescence microscopy. The levels of mRNAs for osteogenic differentiation-re- lated factors (including alkaline phosphatase, osteocalcin, osteopontin and bone morphogenetic protein 2) in the co-culture group were higher than those in the control group, as detected by real-time quantitative PCR. Our findings indicate that dorsal root ganglion neurons promote the proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells, which pro- vides a theoretical basis for in vitro experiments aimed at constructing tissue-engineered bone. 展开更多
关键词 nerve regeneration bone marrow mesenchymal stem cells bone OSTEOBLASTS GANGLION spine neurons co-culture techniques PROLIFERATION differentiation real-time quantitative PCR NSFC grants neural regeneration
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DECnet-VAX网络节点双机系统的实现
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作者 马欢 徐甲同 《西安电子科技大学学报》 EI CAS CSCD 北大核心 1994年第A06期60-66,共7页
基于对DECnet—VAX网络路由层软件的分析,采用双机热备份方法,建立了网络节点双机系统.该系统使用了修改后的路由层协议,使DECnet—VAX网络节点双机系统在路由层上得到实现.
关键词 计算机网络 双机系统 容错技术
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开关电源的待机控制 被引量:1
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作者 陈洁 《电源技术应用》 2012年第10期57-59,共3页
介绍了电流模式控制器UC3842的特点,分析控制器的特色之一-关机技术,提出了可以通过单片机控制开关电源待机的两种方法,并给出了实验结果。
关键词 开关电源 UC3842 关机技术 单片机 待机 切换
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Real-time optimization using gradient adaptive selection and classification from infrared sensors measurement for esterification oleic acid with glycerol
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作者 Iwan Aang Soenandi Taufik Djatna +1 位作者 Ani Suryani Irzaman 《International Journal of Intelligent Computing and Cybernetics》 EI 2017年第2期130-144,共15页
Purpose-The production of glycerol derivatives by the esterification process is subject to many constraints related to the yield of the production target and the lack of process efficiency.An accurate monitoring and c... Purpose-The production of glycerol derivatives by the esterification process is subject to many constraints related to the yield of the production target and the lack of process efficiency.An accurate monitoring and controlling of the process can improve production yield and efficiency.The purpose of this paper is to propose a real-time optimization(RTO)using gradient adaptive selection and classification from infrared sensor measurement to cover various disturbances and uncertainties in the reactor.Design/methodology/approach-The integration of the esterification process optimization using self-optimization(SO)was developed with classification process was combined with necessary condition optimum(NCO)as gradient adaptive selection,supported with laboratory scaled medium wavelength infrared(mid-IR)sensors,and measured the proposed optimization system indicator in the batch process.Business Process Modeling and Notation(BPMN 2.0)was built to describe the tasks of SO workflow in collaboration with NCO as an abstraction for the conceptual phase.Next,Stateflow modeling was deployed to simulate the three states of gradient-based adaptive control combined with support vector machine(SVM)classification and Arduino microcontroller for implementation.Findings-This new method shows that the real-time optimization responsiveness of control increased product yield up to 13 percent,lower error measurement with percentage error 1.11 percent,reduced the process duration up to 22 minutes,with an effective range of stirrer rotation set between 300 and 400 rpm and final temperature between 200 and 210℃ which was more efficient,as it consumed less energy.Research limitations/implications-In this research the authors just have an experiment for the esterification process using glycerol,but as a development concept of RTO,it would be possible to apply for another chemical reaction or system.Practical implications-This research introduces new development of an RTO approach to optimal control and as such marks the starting point for more research of its properties.As the methodology is generic,it can be applied to different optimization problems for a batch system in chemical industries.Originality/value-The paper presented is original as it presents the first application of adaptive selection based on the gradient value of mid-IR sensor data,applied to the real-time determining control state by classification with the SVM algorithm for esterification process control to increase the efficiency. 展开更多
关键词 Gradient technique Infrared sensor real-time optimization Simulation and modelling Support vector machine
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Implementation of Dynamic Line Rating in a Sub-Transmission System for Wind Power Integration
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作者 Saifal Talpur Carl Johan Wallnerstrom +1 位作者 Patrik Hilber Christer Flood 《Smart Grid and Renewable Energy》 2015年第8期233-249,共17页
Based on conventional static line rating method, the actual current carrying capability of overhead conductors cannot be judged. Due to continuous increment in electricity demand and the difficulties associated with n... Based on conventional static line rating method, the actual current carrying capability of overhead conductors cannot be judged. Due to continuous increment in electricity demand and the difficulties associated with new line constructions, the overhead lines are therefore required to be rated based on a method that should establish their real-time capability in terms of electricity transmission. The method used to determine the real-time ampacity of overhead conductors not only can enhance their transmission capacity but can also help in allowing excessive renewable generation in the electricity network. In this research work, the issues related to analyzing an impact of wind power on periodical loading of overhead line as well as finding its static and dynamic ampacities with line current are investigated in detail. Moreover, the investigation related to finding a suitable location for the construction of a 60 MW wind farm is taken on board. Thereafter, the wind park is integrated with a regional grid, owned by Fortum Distribution AB. In addition to that, the electricity generated from the wind park is also calculated in this project. Later on, the work is devoted to finding the static and dynamic line ratings for “VL3” overhead conductor by using IEEE-738-2006 standard. Furthermore, the project also deals with finding the line current and making its comparison with maximum capacity of overhead conductor (VL3) for loading it in such a way that no any violation of safe ground clearance requirements is observed at all. Besides, the line current, knowing the conductor temperature when it transmits the required electricity in the presence of wind power generation is also an important factor to be taken into consideration. Therefore, based on real-time ambient conditions with actual line loading and with the help of IEEE-738-2006 standard, the conductor temperature is also calculated in this project. At the end, an economic analysis is performed to evaluate the financial advantages related to applying the dynamic line ratings approach in place of traditional static line ratings technique across an overhead conductor (VL3) and to know how much beneficial it is to temporarily postpone the rebuilding and/or construction of a new transmission line. Furthermore, an economic analysis related to wind power system is taken into consideration as well to get familiar with the costs related to building and connecting a 60 MW wind farm with the regional grid. 展开更多
关键词 Overhead Conductor STATIC and DYNAMIC Ampacities real-time Weather Conditions STATIC and DYNAMIC LINE RATING techniques WIND Power Integration Regional Grid LINE Current. Conductor Temperature WIND Power ECONOMICS DYNAMIC LINE RATING ECONOMICS
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GB 20943标准发布促进电源行业能效提升
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作者 罗勇进 邓以成 《中国标准化》 2015年第S1期109-112,共4页
GB 20943外置电源能效标准的发布,它限制了高耗能产品的生产、销售和进口,并最终将它们从市场中淘汰,引导消费者购买低损耗、高能效的优质产品,有助于促进电源产品效率的提升、节能技术的进步,加快了电源行业的健康发展,增强了产品的竞... GB 20943外置电源能效标准的发布,它限制了高耗能产品的生产、销售和进口,并最终将它们从市场中淘汰,引导消费者购买低损耗、高能效的优质产品,有助于促进电源产品效率的提升、节能技术的进步,加快了电源行业的健康发展,增强了产品的竞争能力,提升了消费者节能减排意识,使电源产品市场管理更加合理、规范、高效。当前,能效标准GB 20943已与欧美先进能效标准的要求保持同步。它一方面促进我国电源产品生产企业逐步与国际水平接轨,提高国际竞争力。另一方面可以着手建立国际间的相互认可,减少贸易障碍。同时可以为企业制订先进的节能目标,正确引导企业制定合理的发展规划,加强管理,提升企业品牌形象和知名度。 展开更多
关键词 能效标准 能效限定值 能效评价值 节能技术 待机功耗 节能减排 技术性贸易壁垒
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具有温储备失效特征和单重休假Min(N,V)-控制策略的M/G/1可修排队系统 被引量:22
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作者 蔡晓丽 唐应辉 《应用数学学报》 CSCD 北大核心 2017年第5期702-726,共25页
本文考虑具有温储备失效特征和单重休假Min(N,V)-控制策略的M/G/1可修排队系统.在该系统中,服务台有两类故障:一类是服务台在服务员"广义忙期"中可能发生的故障,另一类是服务台在没有为顾客服务的时间段内可能发生的温储备故... 本文考虑具有温储备失效特征和单重休假Min(N,V)-控制策略的M/G/1可修排队系统.在该系统中,服务台有两类故障:一类是服务台在服务员"广义忙期"中可能发生的故障,另一类是服务台在没有为顾客服务的时间段内可能发生的温储备故障,且假设两类故障具有不同的故障率和修复率.运用全概率分解技术、拉普拉斯变换工具以及更新过程理论,研究了系统的瞬态队长分布和稳态队长分布,获得了瞬态队长分布的拉普拉斯变换的递推表达式,得到了在系统容量的优化设计中有重要应用价值的稳态队长分布的递推结果,并证明了稳态队长的随机分解性质.同时还讨论了当休假时间V=0,V→∞与温储备寿命时间Y→∞时的特殊情形.最后,建立了系统长期单位时间内总成本费用函数,用数值计算例子讨论了最优控制策略N~*. 展开更多
关键词 可修排队系统 温储备失效 Min(N V)-控制策略 队长分布 全概率分解技术
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两个三状态部件组成的热贮备可维修系统的可靠性分析和价值分析
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作者 刘承胤 黄万风 曹尔璞 《吉林工业大学学报》 CSCD 1991年第1期1-5,共5页
本文研究由两个相同部件、一个修理工和一个转换开关组成的热贮备系统。用再生点技术求出了系统首次故障前时间分市;系统的可用度和稳态可用度;(0,t]时间内系统平均故障次数和修理工忙的概率。并对系统进行了价值分析,得到(0,t]时间内... 本文研究由两个相同部件、一个修理工和一个转换开关组成的热贮备系统。用再生点技术求出了系统首次故障前时间分市;系统的可用度和稳态可用度;(0,t]时间内系统平均故障次数和修理工忙的概率。并对系统进行了价值分析,得到(0,t]时间内系统获得的平均利润。 展开更多
关键词 热贮备 可靠性分析 可维修系统
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