期刊文献+
共找到2,426篇文章
< 1 2 122 >
每页显示 20 50 100
Energy-Efficient Cluster in Wireless Sensor Network Using Life Time Delay Clustering Algorithms
1
作者 V.Kumar N.Jayapandian P.Balasubramanie 《Computer Systems Science & Engineering》 SCIE EI 2022年第10期77-86,共10页
Through Wireless Sensor Networks(WSN)formation,industrial and academic communities have seen remarkable development in recent decades.One of the most common techniques to derive the best out of wireless sensor network... Through Wireless Sensor Networks(WSN)formation,industrial and academic communities have seen remarkable development in recent decades.One of the most common techniques to derive the best out of wireless sensor networks is to upgrade the operating group.The most important problem is the arrangement of optimal number of sensor nodes as clusters to discuss clustering method.In this method,new client nodes and dynamic methods are used to determine the optimal number of clusters and cluster heads which are to be better organized and proposed to classify each round.Parameters of effective energy use and the ability to decide the best method of attachments are included.The Problem coverage find change ability network route due to which traffic and delays keep the performance to be very high.A newer version of Gravity Analysis Algorithm(GAA)is used to solve this problem.This proposed new approach GAA is introduced to improve network lifetime,increase system energy efficiency and end delay performance.Simulation results show that modified GAA performance is better than other networks and it has more advanced Life Time Delay Clustering Algorithms-LTDCA protocols.The proposed method provides a set of data collection and increased throughput in wireless sensor networks. 展开更多
关键词 WSNS Gravity analysis algorithm-GAA life time delay clustering algorithms-LTDCA end to end delay energy efficient
下载PDF
Phase Wise Supply Chain Model of EOQ with Normal Life Time for Queued Customers: A Computational Approach
2
作者 Sant Sharan Mishra Prem Prakash Mishra 《American Journal of Operations Research》 2012年第3期296-307,共12页
In this paper, we mainly aim to compute the optimal inventory in the phase wise supply chain for queued customers in the interval of lower and upper bounds with particular life of the items. Important performance meas... In this paper, we mainly aim to compute the optimal inventory in the phase wise supply chain for queued customers in the interval of lower and upper bounds with particular life of the items. Important performance measures such as total optimal cost of the system and total expected delivery have also been computed by applying the dynamic programming and Drichlet theorem. Finally, numerical demonstration and sensitivity analysis have also been presented to gain the better perspective of the model. 展开更多
关键词 Supply Chain Correlation NORMAL life time Dynamic PROGRAMMING
下载PDF
Modified DS np Chart Using Generalized Multiple Dependent State Sampling under Time Truncated Life Test
3
作者 Wimonmas Bamrungsetthapong Pramote Charongrattanasakul 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第3期2471-2495,共25页
This study presents the design of a modified attributed control chart based on a double sampling(DS)np chart applied in combination with generalized multiple dependent state(GMDS)sampling to monitor the mean life of t... This study presents the design of a modified attributed control chart based on a double sampling(DS)np chart applied in combination with generalized multiple dependent state(GMDS)sampling to monitor the mean life of the product based on the time truncated life test employing theWeibull distribution.The control chart developed supports the examination of the mean lifespan variation for a particular product in the process of manufacturing.Three control limit levels are used:the warning control limit,inner control limit,and outer control limit.Together,they enhance the capability for variation detection.A genetic algorithm can be used for optimization during the in-control process,whereby the optimal parameters can be established for the proposed control chart.The control chart performance is assessed using the average run length,while the influence of the model parameters upon the control chart solution is assessed via sensitivity analysis based on an orthogonal experimental design withmultiple linear regression.A comparative study was conducted based on the out-of-control average run length,in which the developed control chart offered greater sensitivity in the detection of process shifts while making use of smaller samples on average than is the case for existing control charts.Finally,to exhibit the utility of the developed control chart,this paper presents its application using simulated data with parameters drawn from the real set of data. 展开更多
关键词 Modified DS np chart generalizedmultiple dependent state sampling time truncated life test Weibull distribution average run length average sample size
下载PDF
A Method in Mixed Frequency-time domain for Fatigue Life Estimation of Steel Girders of Cable-stayed Bridges Due to Buffeting 被引量:1
4
作者 顾明 陈礼忠 项海帆 《应用基础与工程科学学报》 EI CSCD 1998年第4期70-79,共10页
发展了斜拉桥钢主梁抖振疲劳寿命的混合时-频域方法.在本方法中,首先建立了桥面处的风速风向概率密度函数,导出的应力谱因其包括背景分量而不再是窄带谱.据应力谱模拟出了疲劳应力的时间历程,并用雨流计数法统计了其幅值特性.基... 发展了斜拉桥钢主梁抖振疲劳寿命的混合时-频域方法.在本方法中,首先建立了桥面处的风速风向概率密度函数,导出的应力谱因其包括背景分量而不再是窄带谱.据应力谱模拟出了疲劳应力的时间历程,并用雨流计数法统计了其幅值特性.基于修正的Miner定理导出了考虑风速风向作用的桥梁主梁抖振疲劳寿命的估算公式,并用此分析了杨浦大桥钢主梁的抖振疲劳寿命.结果表明,风向对抖振疲劳寿命有很大影响;杨浦大桥主梁的疲劳寿命远大于设计寿命. 展开更多
关键词 斜拉桥 钢主梁 抖振 疲劳寿命 混合时-频域
下载PDF
A Multi-Hop Dynamic Path-Selection (MHDP) Algorithm for the Augmented Lifetime of Wireless Sensor Networks
5
作者 Perumal Kalyanasundaram Thangavel Gnanasekaran 《Circuits and Systems》 2016年第10期3343-3353,共12页
In Wireless Sensor Networks (WSN), the lifetime of sensors is the crucial issue. Numerous schemes are proposed to augment the life time of sensors based on the wide range of parameters. In majority of the cases, the c... In Wireless Sensor Networks (WSN), the lifetime of sensors is the crucial issue. Numerous schemes are proposed to augment the life time of sensors based on the wide range of parameters. In majority of the cases, the center of attraction will be the nodes’ lifetime enhancement and routing. In the scenario of cluster based WSN, multi-hop mode of communication reduces the communication cast by increasing average delay and also increases the routing overhead. In this proposed scheme, two ideas are introduced to overcome the delay and routing overhead. To achieve the higher degree in the lifetime of the nodes, the residual energy (remaining energy) of the nodes for multi-hop node choice is taken into consideration first. Then the modification in the routing protocol is evolved (Multi-Hop Dynamic Path-Selection Algorithm—MHDP). A dynamic path updating is initiated in frequent interval based on nodes residual energy to avoid the data loss due to path extrication and also to avoid the early dying of nodes due to elevation of data forwarding. The proposed method improves network’s lifetime significantly. The diminution in the average delay and increment in the lifetime of network are also accomplished. The MHDP offers 50% delay lesser than clustering. The average residual energy is 20% higher than clustering and 10% higher than multi-hop clustering. The proposed method improves network lifetime by 40% than clustering and 30% than multi-hop clustering which is considerably much better than the preceding methods. 展开更多
关键词 Wireless Sensor Networks (WSN) Cluster Based WSN Multi-Hop Mode Residual Energy Average Delay Multi-Hop Dynamic Path-Selection Algorithm life time
下载PDF
A Novel Multiple Dependent State Sampling Plan Based on Time Truncated Life Tests Using Mean Lifetime 被引量:1
6
作者 Pramote Charongrattanasakul Wimonmas Bamrungsetthapong Poom Kumam 《Computers, Materials & Continua》 SCIE EI 2022年第12期4611-4626,共16页
The design of a new adaptive version of the multiple dependent state(AMDS)sampling plan is presented based on the time truncated life test under the Weibull distribution.We achieved the proposed sampling plan by apply... The design of a new adaptive version of the multiple dependent state(AMDS)sampling plan is presented based on the time truncated life test under the Weibull distribution.We achieved the proposed sampling plan by applying the concept of the double sampling plan and existing multiple dependent state sampling plans.A warning sign for acceptance number was proposed to increase the probability of current lot acceptance.The optimal plan parameters were determined simultaneously with nonlinear optimization problems under the producer’s risk and consumer’s risk.A simulation study was presented to support the proposed sampling plan.A comparison between the proposed and existing sampling plans,namely multiple dependent state(MDS)sampling plans and a modified multiple dependent state(MMDS)sampling plan,was considered under the average sampling number and operating characteristic curve values.In addition,the use of two real datasets demonstrated the practicality and usefulness of the proposed sampling plan.The results indicated that the proposed plan is more flexible and efficient in terms of the average sample number compared to the existing MDS and MMDS sampling plans. 展开更多
关键词 Adaptive version of multiple dependent state sampling plan time truncated life test quality level weibull distribution mean lifetime
下载PDF
Physical activity, screen time and pediatric health-related quality of life in the Mississippi Delta 被引量:3
7
作者 Tamara T. Perry Page C. Moore +2 位作者 Karen M. Redwine James M. Robbins Judith L. Weber 《Open Journal of Preventive Medicine》 2012年第1期105-111,共7页
Background: The association of physical activity (PA) and screen time (ST) on health-related quality of life (HRQOL) among predominantly low-income children in the Mississippi Delta region has not been previously desc... Background: The association of physical activity (PA) and screen time (ST) on health-related quality of life (HRQOL) among predominantly low-income children in the Mississippi Delta region has not been previously described. Methods: We performed a cross-sectional survey to assess health risks from a representative sample of the population ≥3 years old in the Delta Region of Arkansas, Louisiana, and Mississippi. Linear models were utilized to examine Pediatric Quality of Life Inventory (PedsQL) scores based on reported PA and ST. Results: Median age of the 371 participants was 9.8 years, 57% were African American, and 26% had annual household income ≤$14,999. Overall, 262 (75%) were categorized as physically active and 48% reported >2 hours ST per day. Children reporting exercising 5 - 7 days per week had significantly better PedsQL total score (84.3 vs 80.8;p 2 hours per day) did not significantly impact HRQOL. Conclusions: Findings suggest that PA among children living in the Mississippi Delta was related to higher HRQOL;however, the positive effects of PA on HRQOL may be less for minority and low-income children. 展开更多
关键词 PHYSICAL ACTIVITY SCREEN time Quality of life PEDIATRICS
下载PDF
Sensitivity of the half-life time of water exchange in coastal waters
8
作者 Zhenhua CHEN Fangli QIAO +1 位作者 Gang WANG Changshui XIA 《Science China Earth Sciences》 SCIE EI CAS CSCD 2019年第4期643-656,共14页
A three-dimensional model was established to investigate water exchange in coastal waters, and applied to Qinzhou Bay(QZB) in the South China Sea. Given the strong tidal current in QZB, a half-life time was calculated... A three-dimensional model was established to investigate water exchange in coastal waters, and applied to Qinzhou Bay(QZB) in the South China Sea. Given the strong tidal current in QZB, a half-life time was calculated for water exchange by filtering the tidal signal from the concentrations of a conservative substance. In a control run driven by the tide, without external inputs and an open boundary concentration of zero, it was estimated that the average half-life time in QZB was 54.8 d. Numerical experiments showed that wind accounted for an 11.9% reduction in the half-life time to 48.3 d. When rivers were included in the model, the half-life time decreased by 74.6% to 13.9 d. Sensitivity experiments showed that the half-life time for water exchange was greatly affected by the concentration of the conservative substance which was used at the open boundary. In response to 10,20, 30, and 40% increases in the boundary concentration, the half-life time increased to 91.5, 168.3, 186.2, and 229.1 d,respectively. Results also suggested that for coastal bays with large intertidal areas such as QZB, consideration of the wet and dry processes produced more accurate simulations of the hydrodynamics and the half-life times. Simulations, which did not incorporate wet and dry processes, were more than likely to have overestimated or underestimated the half-life times for water exchange. 展开更多
关键词 Sensitivity CONVECTION-DIFFUSION model Water exchange HALF-life time Qinzhou BAY SOUTH China SEA
原文传递
Extending the Network Lifetime Using Optimized Energy Efficient Cross Layer Module (OEEXLM) in Wireless Sensor Networks
9
作者 T. V. PADMAVATHY 《Wireless Sensor Network》 2009年第1期27-35,共9页
In wireless sensor network, the primary design is to save the energy consumption as much as possible while achieving the given task. Most of recent researches works have only focused on the individual layer issues and... In wireless sensor network, the primary design is to save the energy consumption as much as possible while achieving the given task. Most of recent researches works have only focused on the individual layer issues and ignore the importance of inter working between different layers in a sensor network. In this paper, we use a cross-layer approach to propose an energy-efficient and extending the life time of the sensor network. This protocol which uses routing in the network layer, and the data scheduling in MAC layer. The main ob-jective of this paper is to provide a possible and flexible approach to solve the conflicts between the require-ments of large scale, long life-time, and multi-purpose wireless sensor networks. This OEEXLM module gives better performance compared to all other existing protocols. The performance of OEEXLM module compared with S-MAC and directed diffusion protocol. 展开更多
关键词 ROUTING MEDIUM ACCESS Control life time of the Network Energy Efficiency OEEXLM MODULE Wireless Sensor Networks
下载PDF
A Time Dependent Inventory Model for Exponential Demand Rate with Constant Production Where Shelf-Life of the Product Is Finite
10
作者 Mohammad Ekramol Islam Shirajul Islam Ukil Md. Sharif Uddin 《Open Journal of Applied Sciences》 2016年第1期38-48,共11页
In this paper a time dependent inventory model is developed on the basis of constant production rate and market demands which are exponentially decreasing. It advances in quest of total average optimum cost considerin... In this paper a time dependent inventory model is developed on the basis of constant production rate and market demands which are exponentially decreasing. It advances in quest of total average optimum cost considering those products which have finite shelf-life. The model also considers the small amount of decay. Without having any sort of backlogs, production starts. Reaching at the desired level of inventories, it stops production. After that due to demands along with the deterioration of the items it initiates its depletion and after certain periods the inventory gets zero. The decay of the products is level dependent. The objective of this paper is to find out the optimum inventory cost and optimum time cycle. The model has also been justified with proving the convex property and by giving a numerical example. 展开更多
关键词 Production Inventory Shelf-life time Dependent Demand Class Production Rate
下载PDF
基于频域和时域法的电池包随机振动疲劳计算对比研究
11
作者 吴光强 李超 +1 位作者 丁丰 章蕾 《湖南大学学报(自然科学版)》 EI CAS CSCD 北大核心 2024年第2期208-218,共11页
针对频域法和时域法在随机振动疲劳计算中的适用性问题,以某型号电池包为研究对象,综合研究了2种方法的计算精度和计算效率.首先,建立电池包有限元模型,并通过模态试验进行验证;其次,以国标GB 38031―2020加速度功率谱密度(PSD)载荷谱... 针对频域法和时域法在随机振动疲劳计算中的适用性问题,以某型号电池包为研究对象,综合研究了2种方法的计算精度和计算效率.首先,建立电池包有限元模型,并通过模态试验进行验证;其次,以国标GB 38031―2020加速度功率谱密度(PSD)载荷谱作为频域载荷输入,并利用傅里叶逆变换技术将其转换为加速度时域载荷;最后,分别基于频域法和时域法计算电池包的振动加速度、应力和疲劳寿命,并进行了计算精度、效率的对比分析和精度的试验验证.结果表明,在电池包总振级和应力均方根值(RMS)方面,频域法和时域法计算结果相近,相对误差小于16%;在加速度和应力峰值方面,频域法“3σ”计算结果与时域法差距较大,若采用“4σ”或“5σ”原则,计算结果与时域法相近,相对误差小于15%;在振动疲劳方面,频域法计算寿命约为时域法的3~6倍,主要原因包括Dirlik模型和应力响应PSD谱差异,其中Dirlik模型造成的差距小于1.5倍;在计算效率方面,频域法比时域法高约134倍.试验数据表明,时域法计算精度更高,适用于结构危险位置振动疲劳的精确计算,而频域法计算效率更高,适用于结构危险位置的快速预测. 展开更多
关键词 电池包 随机振动 疲劳寿命 时域分析 频域分析
下载PDF
载人潜水器有机玻璃视窗蠕变-疲劳特性分析
12
作者 谌伟 张毅 +3 位作者 罗良 高华轩 徐双喜 吴轶钢 《船海工程》 北大核心 2024年第5期29-32,共4页
通过对棒状有机玻璃试样进行短期蠕变试验,揭示载人潜水器视窗玻璃材料的蠕变特性。开展有机玻璃蠕变断裂试验,获得有机玻璃材料的蠕变断裂寿命,给出蠕变断裂时间和保载应力水平成双对数线性相关的结论及相应的线性拟合方程,并开展拉伸... 通过对棒状有机玻璃试样进行短期蠕变试验,揭示载人潜水器视窗玻璃材料的蠕变特性。开展有机玻璃蠕变断裂试验,获得有机玻璃材料的蠕变断裂寿命,给出蠕变断裂时间和保载应力水平成双对数线性相关的结论及相应的线性拟合方程,并开展拉伸疲劳试验获得不同峰值应力下的拉伸疲劳寿命。对300 m观光潜器有机玻璃视窗在不同下潜深度下的应力水平进行分析,并结合基于线性累计损伤理论的时间寿命分数法,实现对300 m载人潜水器有机玻璃视窗考虑保载蠕变的疲劳寿命估算。 展开更多
关键词 有机玻璃视窗 载人潜水器 疲劳寿命 蠕变-疲劳 时间寿命分数法
下载PDF
多发性骨髓瘤组织中miR-29c、miR-195表达水平变化及其与临床病理特征及预后的关系
13
作者 石瑞平 陈兴华 李真 《实用癌症杂志》 2024年第3期425-429,共5页
目的 探讨多发性骨髓瘤(MM)组织中miR-29c、miR-195表达水平变化及其与临床病理特征及预后的关系。方法 选取75例MM患者作为病例组,另选取同期就诊的75例骨髓象检查为正常的非血液系统疾病患者作为对照组。采用实时荧光定量PCR(q-PCR)... 目的 探讨多发性骨髓瘤(MM)组织中miR-29c、miR-195表达水平变化及其与临床病理特征及预后的关系。方法 选取75例MM患者作为病例组,另选取同期就诊的75例骨髓象检查为正常的非血液系统疾病患者作为对照组。采用实时荧光定量PCR(q-PCR)检测骨髓组织中miR-29c、miR-195表达水平,根据检测平均值将miR-29c、miR-195分为高水平组和低水平组,分析miR-29c、miR-195表达水平与临床病理特征及预后的相关性。结果 病例组骨髓组织miR-29c、miR-195表达水平低于对照组(P<0.05)。miR-29c低水平组中ISS分期Ⅲ期及血清白蛋白水平<35 g/L的患者占比高于高水平组(P<0.05);miR-195低水平组中ISS分期Ⅲ期及血清白蛋白水平<35 g/L的患者占比高于高水平组(P<0.05);miR-29c低水平组的生存期低于高水平组(P<0.05),miR-195低水平组的生存期低于高水平组(P<0.05)。miR-29c、miR-195表达水平与ISS分期呈负相关(P<0.05),与血清白蛋白、生存期呈正相关(P<0.05)。结论miR-29c、miR-195均在MM患者骨髓组织中低表达,且低表达miR-29c、miR-195患者的生存期较短。miR-29c、miR-195表达水平与ISS分期呈正相关,与血清白蛋白、生存期呈负相关。 展开更多
关键词 多发性骨髓瘤 miR-29c miR-195 生存期
下载PDF
1990—2019年亚洲主要国家与全球宫颈癌疾病负担变化趋势分析
14
作者 何贤英 王振博 +2 位作者 初云天 赵杰 崔芳芳 《中国卫生统计》 CSCD 北大核心 2024年第4期487-490,496,共5页
目的分析1990—2019亚洲主要国家及全球宫颈癌疾病负担,为制定宫颈癌防控策略提供科学依据。方法收集1990—2019年全球疾病负担研究(global burden of disease,GBD)数据,利用发病、死亡、伤残调整寿命年(disability-adjusted life years... 目的分析1990—2019亚洲主要国家及全球宫颈癌疾病负担,为制定宫颈癌防控策略提供科学依据。方法收集1990—2019年全球疾病负担研究(global burden of disease,GBD)数据,利用发病、死亡、伤残调整寿命年(disability-adjusted life years,DALY)等指标定量评估宫颈癌的疾病负担情况,采用估计百分百变化(estimated annual percent change,EAPC)分析疾病负担时间变化趋势。结果1990—2019年,全球宫颈癌标化发病率从7.64/10万下降至6.81/10万,标化死亡率从4.46/10万降低至3.40/10万,标化DALY率从139.98/10万下降至107.20/10万,年平均降低分别为0.39%、0.96%、0.94%(EAPC<0,P<0.05)。亚洲主要国家中,中国的标化发病率从4.20/10万上升至5.53/10万,平均每年增长1.63%(EAPC>0,P>0.05)。中国宫颈癌的死亡数从2.64万增加到5.34万,相对增长1.02倍,全球及亚洲主要国家标化死亡率、标化DALY率均呈逐年下降趋势,而中国未出现下降趋势。相关分析显示,发病率与社会人口指数(socio-demographic index,SDI)无明显相关性(ρ=-0.13,P=0.11),死亡率与SDI呈负相关(ρ=-0.74,P<0.001),DALY与SDI也呈负相关(ρ=-0.77,P<0.001)。结论中国宫颈癌的标化发病率、死亡率逐年增加,疾病负担呈上升趋势,应积极采取科学有效的防控措施,降低宫颈癌疾病负担。 展开更多
关键词 宫颈癌 伤残调整寿命年 疾病负担 时间趋势
下载PDF
马克思自由时间理论与精神生活共同富裕的实现
15
作者 高晓红 单鑫 《南昌大学学报(人文社会科学版)》 CSSCI 北大核心 2024年第4期42-52,共11页
在马克思的理论中,自由时间指不被生活资料的直接生产占去,劳动者可以自由支配、在其中自主活动,并能够用于自我发展的时间,其价值旨向在于促进人的自由全面发展。在资本主义社会中,劳动者深受工作日延长与劳动强度增加的双重挤压,不仅... 在马克思的理论中,自由时间指不被生活资料的直接生产占去,劳动者可以自由支配、在其中自主活动,并能够用于自我发展的时间,其价值旨向在于促进人的自由全面发展。在资本主义社会中,劳动者深受工作日延长与劳动强度增加的双重挤压,不仅无法在劳动中享受自由,而且在资本的规训中丧失生命活动原有的丰富性。劳动时间与自由时间之间对立的扬弃关键在于资本主义生产方式的彻底变革。当前,精神生活共同富裕的实现需要有充裕的自由时间,并把这种自由时间的运用作为必要的基础。然而,由于工作与生活边界的模糊化,消费主义下的空虚与不安,加上不稳定的生活状态,自由时间量的增长与质的提升都面临挑战。在新时代新征程中,不断满足人民群众多样化、多层次、多方面的精神文化需求,需要坚持数字经济赋能社会高质量发展,以保障自由时间量的增长,将社会主义核心价值观融入日常生活,以实现自由时间质的丰盈,引导人民群众在体面劳动中提升精神境界,创造新的美好生活。 展开更多
关键词 马克思 自由时间 劳动 精神生活 共同富裕
下载PDF
基于MsTCN-Transformer模型的轴承剩余使用寿命预测研究 被引量:2
16
作者 邓飞跃 陈哲 +1 位作者 郝如江 杨绍普 《振动与冲击》 EI CSCD 北大核心 2024年第4期279-287,共9页
剩余使用寿命(remaining useful life, RUL)预测是PHM的核心问题之一,复杂的运行工况往往导致设备部件经历不同的故障退化过程,给RUL准确预测带来了巨大挑战。为此,提出了一种多尺度时间卷积网络(multi-scale temporal convolutional ne... 剩余使用寿命(remaining useful life, RUL)预测是PHM的核心问题之一,复杂的运行工况往往导致设备部件经历不同的故障退化过程,给RUL准确预测带来了巨大挑战。为此,提出了一种多尺度时间卷积网络(multi-scale temporal convolutional network, MsTCN)与Transformer(MsTCN-Transformer)融合模型用于变工况下滚动轴承RUL预测。该方法设计了一种新的多尺度膨胀因果卷积单元(multi-scale dilated causal convolution unit, MsDCCU),能够自适应地挖掘滚动轴承全寿命信号中固有的时序特征信息;然后构建了基于自注意力机制的Transformer网络模型,在克服预测序列记忆力退化的基础上,准确学习时序特征与轴承RUL之间的映射关系。此外,通过对轴承不同故障退化阶段所提取的时序特征可视化分析,验证了所提方法在变工况下所提取的时序特征泛化性较好。多种工况条件下滚动轴承RUL预测试验表明,所提方法能够较为准确地实现变工况下轴承的RUL预测,相比当前多种方法RUL预测结果准确性更高。 展开更多
关键词 剩余使用寿命 时序特征 时间卷积网络 Transformer网络 滚动轴承
下载PDF
高含水油田“二三结合”转换时机优化
17
作者 蔡明俊 何书梅 +4 位作者 刘同敬 李晓良 魏朋朋 李健 冯国君 《中国科技论文》 CAS 2024年第1期57-62,共6页
针对现有转换时机研究方法无法满足高含水期老油田“二三结合”转换时机优化设计需要的问题,在综合分析三次采油转换时机和技术经济评价方法的基础上,考虑工程技术可行性和经济效益可行性,提出综合考虑技术、经济、社会价值的“二三结... 针对现有转换时机研究方法无法满足高含水期老油田“二三结合”转换时机优化设计需要的问题,在综合分析三次采油转换时机和技术经济评价方法的基础上,考虑工程技术可行性和经济效益可行性,提出综合考虑技术、经济、社会价值的“二三结合”全生命周期开发价值链理念,建立高含水期老油田“二三结合”全生命周期效益稳产开发价值链模型,并实例分析“二三结合”转换时机对油藏最终采收率和生命周期的敏感性。结果表明,稳产、效益、生命周期是“二三结合”全生命周期效益稳产开发的主要考虑因素,转换时机对效益和稳产的影响是相对立的。 展开更多
关键词 二三结合 转换时机 优化理论 全生命周期 开发价值链模型
下载PDF
复方红豆杉胶囊维持治疗气虚痰瘀证晚期非小细胞肺癌的多中心、大样本、前瞻性队列研究
18
作者 王学谦 张英 +14 位作者 董军 王维 焦智民 张勇 蒋益兰 杨祖贻 薛文翰 王慧娟 都振利 王新杰 李润浦 孙红梅 曹晓红 张美英 侯炜 《现代肿瘤医学》 CAS 2024年第9期1631-1637,共7页
目的:探讨复方红豆杉胶囊维持治疗气虚痰瘀证晚期非小细胞肺癌(non-small cell lung cancer,NSCLC)的临床疗效和安全性。方法:采用多中心、大样本、前瞻性队列研究方法,纳入一线化疗4~6周期后疗效评价疾病稳定以上进入维持治疗阶段患者... 目的:探讨复方红豆杉胶囊维持治疗气虚痰瘀证晚期非小细胞肺癌(non-small cell lung cancer,NSCLC)的临床疗效和安全性。方法:采用多中心、大样本、前瞻性队列研究方法,纳入一线化疗4~6周期后疗效评价疾病稳定以上进入维持治疗阶段患者,根据患者意愿分为治疗组160例,对照组109例。对照组根据鳞癌和非鳞癌分别给予吉西他滨和培美曲塞单药化疗维持治疗,治疗组给予复方红豆杉胶囊维持治疗。均以21天为1个疗程,两组干预至少2个疗程,每周期进行生活质量评价,每2疗程进行影像学疗效评价。比较两组疾病无进展生存时间(progression-free survival time,PFS)、生活质量,同时进行药物安全性评价。结果:269例入组患者中,246例患者出现PFS终点事件(91.45%),其中治疗组145例,中位PFS为106天,对照组101例,中位PFS为120天,两组PFS比较差异无统计学意义(P>0.05)。采用美国肺癌生存质量量表(FACT-L4.0版)和欧洲五维健康量表中视觉模拟量表(EQ-5D-VAS)对两组患者生活质量评分进行比较,两种生活质量评价量表均提示治疗组较对照组在提高生活质量方面存在优势(P<0.05)。治疗期间两组共有19例患者出现ADR,治疗组7例(占治疗组人数4.38%),对照组12例(占对照组人数11.01%),ADR发生率在治疗组中更低,尤其表现在骨髓抑制不良反应的发生率方面。结论:在延长PFS方面,复方红豆杉胶囊维持治疗气虚痰瘀证晚期NSCLC的疗效非劣于现代医学单药维持化疗,且在高生活质量、低不良反应方面,复方红豆杉胶囊更具有一定优势。 展开更多
关键词 复方红豆杉胶囊 非小细胞肺癌 维持治疗 疾病无进展生存时间 生活质量 队列研究
下载PDF
论湖南近代社会
19
作者 周秋光 陈国连 《云梦学刊》 2024年第2期9-21,共13页
湖南近代社会构成是湖南近代社会体系各组成部分中具有稳定的结构与秩序的基本状态和社会结构,主要包括人口、家庭、宗族、社群,它起着推动社会整体发展、形成社会情状面貌的基础性作用。湖南近代社会生活是湖南近代的个人、群体为满足... 湖南近代社会构成是湖南近代社会体系各组成部分中具有稳定的结构与秩序的基本状态和社会结构,主要包括人口、家庭、宗族、社群,它起着推动社会整体发展、形成社会情状面貌的基础性作用。湖南近代社会生活是湖南近代的个人、群体为满足多方面、多层次的需要而进行的全部生活活动,涵盖了湖南近代社会的个人、群体浅层次的日常生活活动和深层次的人际交往活动,如衣食住行、风俗礼仪、休闲娱乐等,呈现出中西结合、新旧混杂的发展特征和中西融合变通的价值趋向。湖南近代社会功能是在湖南近代社会构成的基础上满足湖南近代社会生活多重需要所须具有的功能,包括社会教化功能、社会救济功能、社会控制功能和社会治理功能。 展开更多
关键词 湖南近代 社会构成 社会生活 社会功能
下载PDF
结合加速时温数据和加权外推的橡胶老化寿命预测
20
作者 吕向飞 任琪 +1 位作者 张博 邓钦文 《机械科学与技术》 CSCD 北大核心 2024年第6期1072-1077,共6页
针对加速数据外推合理性瓶颈,在高温加速试验数据的基础上,提出加权外推的方法实现橡胶寿命的准确预测。首先,建立橡胶性能的非线性加速退化模型,并采用非线性最小二乘法实现对不同温度下的加速因子进行识别;其次,建立加速因子和加速温... 针对加速数据外推合理性瓶颈,在高温加速试验数据的基础上,提出加权外推的方法实现橡胶寿命的准确预测。首先,建立橡胶性能的非线性加速退化模型,并采用非线性最小二乘法实现对不同温度下的加速因子进行识别;其次,建立加速因子和加速温度的阿累尼乌斯模型,根据误差特性进行活化能的加权推算;最后,由活化能推算出使用温度下的寿命,通过已有数据的建模验证了方法的有效性。研究可为提升橡胶零部件的加速寿命预测的准确性提供支撑,同时也可为其他机械零部件的可靠性评估提供参考。 展开更多
关键词 橡胶 老化寿命 时温叠加 加速退化 加权外推
下载PDF
上一页 1 2 122 下一页 到第
使用帮助 返回顶部