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Effects of Health Education with Problem-Based Learning Approaches on the Knowledge, Attitude, Practice and Coping Skills of Women with High-Risk Pregnancies in Plateau Areas
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作者 Ying Wu Suolang Sezhen +5 位作者 Renqing Yuzhen Hong Wei Zhijuan Zhan Baima Hongying Yuhong Zhang Lihong Liu 《Open Journal of Nursing》 2024年第5期192-199,共8页
Objective: Given the unique cultural background, way of life, and physical environment of the Tibetan Plateau, this study aims to investigate the effects of health education using problem-based learning (PBL) approach... Objective: Given the unique cultural background, way of life, and physical environment of the Tibetan Plateau, this study aims to investigate the effects of health education using problem-based learning (PBL) approaches on the knowledge, attitude, practice, and coping skills of women with high-risk pregnancies in this region. Methods: 76 high-risk pregnancy cases were enrolled at Tibet’s Linzhi People’s Hospital between September 2023 and April 2024. 30 patients admitted between September 2023 and December 2023 were selected as the control group and were performed with regular patient education. 46 patients admitted between January 2024 and April 2024 were selected as the observation group and were performed regular patient education with problem-based learning approaches. Two groups’ performance on their health knowledge, attitude, practice and coping skills before and after interventions were evaluated, and patient satisfaction were measured at the end of the study. Results: There was no statistical significance (P P P Conclusions: Health education with problem-based learning approaches is worth promoting as it can help high-risk pregnant women in plateau areas develop better health knowledge, attitude and practice and healthier coping skills. Also, it can improve patient sanctification. 展开更多
关键词 Plateau areas Patients with high-risk Pregnancies Problem-Based Learning Health Education Health Knowledge Attitude and Practice Coping Skills
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Cost-benefit analysis of esophageal cancer endoscopic screening in high-risk areas of China 被引量:33
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作者 Juan Yang wen-Qiang wei +3 位作者 Jin Niu Zhi-Cai Liu Chun-Xia Yang You-Lin Qiao 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第20期2493-2501,共9页
AIM:To estimate the cost-benefit of endoscopic screening strategies of esophageal cancer(EC)in high-risk areas of China. METHODS:Markov model-based analyses were conducted to compare the net present values(NPVs)and th... AIM:To estimate the cost-benefit of endoscopic screening strategies of esophageal cancer(EC)in high-risk areas of China. METHODS:Markov model-based analyses were conducted to compare the net present values(NPVs)and the benefit-cost ratios(BCRs)of 12 EC endoscopic screening strategies.Strategies varied according to the targeted screening age,screening frequencies,and follow-up intervals.Model parameters were collected from population-based studies in China,published literatures,and surveillance data. RESULTS:Compared with non-screening outcomes,all strategies with hypothetical 100 000 subjects saved life years.Among five dominant strategies determined by the incremental cost-effectiveness analysis,screening once at age 50 years incurred the lowest NPV(international dollar-I$55 million)and BCR(2.52).Screening six times between 40-70 years at a 5-year interval[i.e., six times(40)f-strategy]yielded the highest NPV(I$99 million)and BCR(3.06).Compared with six times(40)fstrategy,screening thrice between 40-70 years at a 10-year interval resulted in relatively lower NPV,but the same BCR. CONCLUSION:EC endoscopic screening is cost-beneficial in high-risk areas of China.Policy-makers should consider the cost-benefit,population acceptance,and local economic status when choosing suitable screening strategies. 展开更多
关键词 Cost-benefit analysis Esophageal cancer ENDOSCOPY SCREENING high-risk area
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Quantitative analysis of biotechnical reinforcement for a steep slope consisting of composite coal-gangue-soil medium adjacent to a mined-out area 被引量:3
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作者 Xingping Lai Mowen Xie +1 位作者 Fenhua Ren Meifeng Cai 《Journal of University of Science and Technology Beijing》 CSCD 2005年第6期489-494,共6页
The engineering and geological characteristics of a steep slope consisting of coal gangue, rock and soil medium in Huating coal mine have been comprehensively investigated. Owing to humid weather, heavy rainfall, vege... The engineering and geological characteristics of a steep slope consisting of coal gangue, rock and soil medium in Huating coal mine have been comprehensively investigated. Owing to humid weather, heavy rainfall, vegetation and porous characteristics of the soil and rock mass, the steep slope will be destabilized and induce mud-rock flow or derive hazard easily. Firstly, based on the classical slope reinforcement theory, some regularity between the shear and displacement in the destabilized zone of the slope with or without root strength contribution is presented. Then, based on the experimental and statistical analysis of root strength, hydrological characteristics and stability status, etc., some possible biotechnical techniques for reinforcement of the steep slope have been suggested. These methods are important for quantitative analysis of destabilization of the slope and design of the biotechnical reinforcement. 展开更多
关键词 mined-out area coal-gangue-soil composite medium steep slope root-soil effect biotechnical reinforcement
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Reflections on the New Classification of Tumors by the WHO and Changes in Esophageal Cancer in a High-risk Area 被引量:1
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作者 Zhifeng Chen 《Chinese Journal of Clinical Oncology》 CSCD 2006年第1期61-65,共5页
ABSTRACT In year 2000, a book entitled the Pathology and Genetics of Tumors of the Digestive System was published by the WHO, presenting some new diagnostic criteria and treatment principles. I have analyzed the epide... ABSTRACT In year 2000, a book entitled the Pathology and Genetics of Tumors of the Digestive System was published by the WHO, presenting some new diagnostic criteria and treatment principles. I have analyzed the epidemiologic change of tumors in over 30 years in the high-risk area with esophageal cancer. The following phenomenon was found: accompanied by the sharp decrease in the incidence and mortality of esophageal cancer, there was an increase in the incidence and death rate of stomach cancer involving cardiac cancer. This fact should be considered when analyzing the sharp decrease in esophageal cancer incidence and mortality rate. More attention was given to diagnosis of cardiac cancer; at the same time it is more practical to improve the early screening of cancers. To observe the development of high and low - grade intraepithelial neoplasms will be an urgent task for esophageal cancer research in the high risk area, according to WHO's new classification. 展开更多
关键词 WHO tumor new classification epidemiology esophageal cancer the high-risk area.
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Hot ductility behavior of a Fe-0.3C-9Mn-2Al medium Mn steel 被引量:6
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作者 Yong-jin Wang Shuai Zhao +1 位作者 Ren-bo Song Bin Hu 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2021年第3期422-429,共8页
The hot ductility of a Fe-0.3C-9Mn-2Al medium Mn steel was investigated using a Gleeble3800 thermo-mechanical simulator.Hot tensile tests were conducted at different temperatures(600-1300℃)under a constant strain rat... The hot ductility of a Fe-0.3C-9Mn-2Al medium Mn steel was investigated using a Gleeble3800 thermo-mechanical simulator.Hot tensile tests were conducted at different temperatures(600-1300℃)under a constant strain rate of 4×10^(−3)s^(−1).The fracture behavior and mechanism of hot ductility evolution were discussed.Results showed that the hot ductility decreased as the temperature was decreased from 1000℃.The reduction of area(RA)decreased rapidly in the specimens tested below 700℃,whereas that in the specimen tested at 650℃was lower than 65%.Mixed brittle-ductile fracture feature is reflected by the coexistence of cleavage step,intergranular facet,and dimple at the surface.The fracture belonged to ductile failure in the specimens tested between 720-1000℃.Large and deep dimples could delay crack propagation.The change in average width of the dimples was in positive proportion with the change in RA.The wide austenite-ferrite intercritical temperature range was crucial for the hot ductility of medium Mn steel.The formation of ferrite film on austenite grain boundaries led to strain concentration.Yield point elongation occurred at the austenite-ferrite intercritical temperature range during the hot tensile test. 展开更多
关键词 medium Mn steel hot ductility reduction of area fracture behavior microstructure characterization
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Prediction of the position of coal particles in an air dense medium fluidized bed system 被引量:5
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作者 Prusti Pallishree Sahu Ashok K. Biswal Surendra K. 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2015年第3期421-427,共7页
An air dense medium fluidized bed separator(ADMFBS) is used for dry beneficiation of coal using ultrafine magnetite particles as a pseudo-fluid medium. In this process, the coal particle gains additional weight due to... An air dense medium fluidized bed separator(ADMFBS) is used for dry beneficiation of coal using ultrafine magnetite particles as a pseudo-fluid medium. In this process, the coal particle gains additional weight due to coating on its surface and deposition at dead zone area by fine magnetite particles.Hence, the effective density of coal particle increases and the position of coal particle changes accordingly. In this work, an attempt was made to predict the position of coal particle in non-bubbling condition dense medium fluidized bed system. Coal particles of different shape such as cubical, rectangular prism,spherical and triangular prism with different projected area and density were used. The results show that the position of coal particle in air dense medium fluidized bed follows descending order with respect to the increase of density, projected area of coal particle and different shapes(i.e., triangular prism, cubical,rectangular prism and spherical). Empirical mathematical correlations were developed to predict the position of coal particle. 展开更多
关键词 Coal beneficiation Pseudo-fluid medium Dead zone area Effective density
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Energy-Efficieng MAC Protocols for Wireless Body Area Networks: A Survey
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作者 Sai Anand Gopalan Jong-Tae Park 《China Communications》 SCIE CSCD 2011年第5期1-10,共10页
In this paper, we provide a comprehensive survey of key energy-efficient Medium Access Control (MAC) protocols for Wireless Body Area Networks (WBANs). At the outset, we outline the crucial attributes of a good MAC pr... In this paper, we provide a comprehensive survey of key energy-efficient Medium Access Control (MAC) protocols for Wireless Body Area Networks (WBANs). At the outset, we outline the crucial attributes of a good MAC protocol for WBAN. Several sources that contribute to the energy inefficiency of WBAN are identified, and features of the various MAC protocols qualitatively compared. Then, we further investigate some representative TDMA-based energy-efficient MAC protocols for WBAN by emphasizing their strengths and weaknesses. Finally, we conclude with a number of open research issues with regard to WBAN MAC layer. 展开更多
关键词 medium Access Control (MAC) Wireless Body area Networks (WBANs) ENERGY-EFFICIENCY
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MAC Layer Resource Allocation for Wireless Body Area Networks
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作者 Qinghua Shen Xuemin (Sherman) Shen +1 位作者 Tom H.Luan Jing Liu 《ZTE Communications》 2014年第3期13-21,共9页
Wireless body area networks (WBANs) can provide low-cost, timely healthcare services and are expected to be widely used for e-healthcare in hospitals. In a hospital, space is often limited and multiple WBANs have to... Wireless body area networks (WBANs) can provide low-cost, timely healthcare services and are expected to be widely used for e-healthcare in hospitals. In a hospital, space is often limited and multiple WBANs have to coexist in an area and share the same channel in order to provide healthcare services to different patients. This causes severe interference between WBANs that could significantly reduce the network throughput and increase the amount of power consumed by sensors placed on the body. There-fore, an efficient channel-resource allocation scheme in the medium access control (MAC) layer is crucial. In this paper, we devel-op a centralized MAC layer resource allocation scheme for a WBAN. We focus on mitigating the interference between WBANs and reducing the power consumed by sensors. Channel and buffer state are reported by smartphones deployed in each WBAN, and channel access allocation is performed by a central controller to maximize network throughput. Sensors have strict limitations in terms of energy consumption and computing capability and cannot provide all the necessary information for channel allocation in a timely manner. This deteriorates network performance. We exploit the temporal correlation of the body area channel in order to minimize the number of channel state reports necessary. We view the network design as a partly observable optimization prob-lem and develop a myopic policy, which we then simulate in Matlab. 展开更多
关键词 medium access control (MAC) wireless body area networks (WBANs) resource allocation interference mitigation partially observable optimization
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DQCA:a New Medium Access Control Protocol for MANs
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作者 孙海荣 《High Technology Letters》 EI CAS 1996年第1期42-46,共5页
A new medium access control protocol for MANs named DQCA(Distributed QueueCyclic Access)is presented in this paper.When the users of DQCA MAN transfer long files,the network will reach a steady state which is fair aft... A new medium access control protocol for MANs named DQCA(Distributed QueueCyclic Access)is presented in this paper.When the users of DQCA MAN transfer long files,the network will reach a steady state which is fair after a transient period.The transient pe-riod is shorter than that of DQDB.DQCA MAN has the flexibility in bandwidth allocation:the users can achieve different throughputs if the parameters,Pmax(i),are set to be differ-ent.The implementation of priority mechanism is simpler than that of DQDB. 展开更多
关键词 Metropolitan area network medium access control protocol DQDB
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中深层稠油水平井前置CO_(2)蓄能压裂技术 被引量:4
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作者 杨兆臣 卢迎波 +5 位作者 杨果 黄纯 弋大琳 贾嵩 吴永彬 王桂庆 《岩性油气藏》 CAS CSCD 北大核心 2024年第1期178-184,共7页
利用准噶尔盆地西北缘乌夏地区中深层稠油油藏参数,对水平井前置CO_(2)蓄能压裂技术的开发机理、关键操作参数及开发效果进行了详细研究。研究结果表明:①伴随压裂—焖井—生产等开发阶段的延伸,前置CO_(2)蓄能压裂后的油井逐步显现出... 利用准噶尔盆地西北缘乌夏地区中深层稠油油藏参数,对水平井前置CO_(2)蓄能压裂技术的开发机理、关键操作参数及开发效果进行了详细研究。研究结果表明:①伴随压裂—焖井—生产等开发阶段的延伸,前置CO_(2)蓄能压裂后的油井逐步显现出增能改造、扩散降黏、膨胀补能、释压成泡沫油流等特性,井底流压提高了2~4MPa,CO_(2)扩散至油藏的1/3,原油黏度降至500mPa·s以下,泡沫油流明显;②研究区最优压裂段间距为60m、裂缝半长为90m、裂缝导流能力为10t/m,CO_(2)最佳注入强度为1.5m3/m,注入速度为1.8m3/min,油井焖井时间为30d,油藏采收率提高了2%~3%;③通过与常规压裂生产效果进行对比,前置CO_(2)蓄能压裂技术可使产油量提高5.2t/d,预测CO_(2)换油率达2.45,开发效果显著提升。 展开更多
关键词 中深层稠油 水平井 二氧化碳蓄能压裂 低碳采油 乌夏地区 准噶尔盆地
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中远海区域水雷威胁分析 被引量:1
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作者 崔鹏 刘鹏 +2 位作者 王义涛 胡易舟 刘殿文 《舰船电子工程》 2024年第2期10-13,54,共5页
根据布雷作战方在远离大陆港岸依托的较远大陆架和一岛链海区及一岛链以外中远海区域的布雷作战形式,针对海区环境特点对中远海主要水雷威胁区的水雷类型和障碍样式进行分析,可为海上编队中远海对水雷防御需求提供依据,对中远海反水雷... 根据布雷作战方在远离大陆港岸依托的较远大陆架和一岛链海区及一岛链以外中远海区域的布雷作战形式,针对海区环境特点对中远海主要水雷威胁区的水雷类型和障碍样式进行分析,可为海上编队中远海对水雷防御需求提供依据,对中远海反水雷能力建设具有重要意义。 展开更多
关键词 中远海 水雷 威胁 需求分析
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削痂清创与水刀清创治疗中面积深Ⅱ度烧伤创面的临床效果比较 被引量:1
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作者 刘礼平 邓涛 朱鹏 《中国医学创新》 CAS 2024年第15期131-135,共5页
目的:比较中面积深Ⅱ度烧伤患者应用削痂清创与水刀清创治疗的临床效果。方法:选取2021年1月—2023年3月吉安市中心人民医院收治的中面积深Ⅱ度烧伤患者,共82例,按照随机数字表法分成水刀清创组(41例)与削痂清创组(41例)。水刀清创组采... 目的:比较中面积深Ⅱ度烧伤患者应用削痂清创与水刀清创治疗的临床效果。方法:选取2021年1月—2023年3月吉安市中心人民医院收治的中面积深Ⅱ度烧伤患者,共82例,按照随机数字表法分成水刀清创组(41例)与削痂清创组(41例)。水刀清创组采用水刀清创治疗,削痂清创组采用削痂清创治疗。比较两组临床指标、预后情况、创面愈合质量、炎症因子及疼痛介质。结果:水刀清创组每1%面积清创时间、创面愈合时间、住院时间均较削痂清创组短,创面细菌菌落数更少,差异均有统计学意义(P<0.05)。相较削痂清创组,水刀清创组二次清创率更低,差异有统计学意义(P<0.05)。相较削痂清创组,水刀清创组改良温哥华瘢痕评估量表(mVSS)评分均更低,差异均有统计学意义(P<0.05)。治疗后,两组降钙素原(PCT)、C反应蛋白(CRP)水平均较治疗前下降,相较削痂清创组,水刀清创组均更低,差异均有统计学意义(P<0.05)。治疗后,两组5-羟色胺(5-HT)、神经肽Y(NPY)水平均较治疗前下降,相较削痂清创组,水刀清创组均更低,差异均有统计学意义(P<0.05)。结论:与削痂清创比较,中面积深Ⅱ度烧伤患者应用水刀治疗的效果更好,能够改善临床指标及预后情况,促进创面良好愈合,调节炎症因子、疼痛介质水平。 展开更多
关键词 中面积深Ⅱ度烧伤创面 削痂清创 水刀
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贵州普克金矿区黄铁矿和方解石地球化学特征及地质意义
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作者 刘旭 戢兴忠 +1 位作者 陈强 李源洪 《现代地质》 CAS CSCD 北大核心 2024年第4期977-990,共14页
贵州普克金矿区位于我国著名的滇-黔-桂“金三角”地区泥堡大型金矿西南方向的外围区域,与泥堡金矿处于相同的大地构造环境,地层特征、构造样式基本相同,成矿地质条件良好,对其开展成矿流体性质和物质来源研究,有助于理解普克矿区金的... 贵州普克金矿区位于我国著名的滇-黔-桂“金三角”地区泥堡大型金矿西南方向的外围区域,与泥堡金矿处于相同的大地构造环境,地层特征、构造样式基本相同,成矿地质条件良好,对其开展成矿流体性质和物质来源研究,有助于理解普克矿区金的成矿作用,并为下一步找矿勘探提供新的参考。本文在对普克金矿区地表发育的(褐铁矿化)黄铁矿-方解石脉进行野外地质调查的基础上,开展矿物学、方解石稀土元素以及黄铁矿电子探针与微区原位LA-ICP-MS分析,结果显示普克金矿区内大部分方解石脉显示出与泥堡金矿床不含矿方解石脉相似的稀土元素配分特征,少数方解石样品显示出与黔西南卡林型金矿成矿期方解石稀土元素一样的中稀土元素富集和Eu正异常特征。该类方解石脉中的黄铁矿Au元素含量高出平均地壳丰度及沉积成因黄铁矿中Au的含量几个数量级,且Au在黄铁矿中以Au+离子形式存在,表明这些黄铁矿形成于金成矿期的热液环境。含金方解石出现中稀土元素富集模式和Eu正异常特征,表明金成矿流体系还原性质。由于地壳抬升剥蚀的影响,普克金矿区内中稀土元素富集、Eu正异常的方解石脉在地表的露头较少,也可能与普克金矿有利成矿地层层位(二叠系峨眉山玄武岩组)埋深较大、能运移到现今地表层位(三叠系永宁镇组)的成矿热液相对较少有关,指示深部有较好的金成矿潜力。 展开更多
关键词 地球化学 热液方解石 黄铁矿 中稀土元素富集 普克金矿区
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高比例分布式电源配电网中低压柔性互联协调规划
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作者 彭寒梅 尹棠 +3 位作者 肖千皓 谭貌 苏永新 李辉 《中国电力》 CSCD 北大核心 2024年第8期117-129,共13页
柔性互联技术是解决高比例分布式电源(distributed generation,DG)配电网面临诸多问题的有效手段之一。提出了一种基于多层优化的配电网中压与低压柔性互联协调规划方法。首先,建立基于电力电子柔性互联设备(flexible interconnected de... 柔性互联技术是解决高比例分布式电源(distributed generation,DG)配电网面临诸多问题的有效手段之一。提出了一种基于多层优化的配电网中压与低压柔性互联协调规划方法。首先,建立基于电力电子柔性互联设备(flexible interconnected devices,FID)的中低压柔性互联配电网潮流模型。然后,构建三层协调规划模型,上层以低压FID年运行成本及台区变压器负载率的年方差最小为目标,中层以中压FID年运行成本及从上级电网年购电成本最小为目标,分别决策低压和中压FID的安装位置与容量,下层以各场景的从上级电网购电成本最小为目标优化系统运行,并采用自适应粒子群优化和二阶锥规划相结合的混合算法求解。最后,采用含高比例DG的IEEE 33节点配电网进行算例分析,通过柔性互联规划系统的年综合运行成本降低了19.01%,台区变压器负载率的年方差减少了82.59%,验证了所提规划模型的有效性。 展开更多
关键词 分布式电源 中低压柔性互联 协调规划 电力电子柔性互联设备 台区变压器负载率
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大中型灌区量测控设施整体规划与总体布局探讨
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作者 谢崇宝 武前明 +1 位作者 郝振刚 朱洁 《中国农村水利水电》 北大核心 2024年第9期90-93,共4页
大中型灌区供水服务应全面考虑水资源的流动性、循环性、系统性等自然属性,从系统治理的视角,统筹考虑灌区上下游、左右岸、地表地下等水流全过程的配置效率。针对目前大中型灌区量测水设施在建设布局中的常见问题,提出了灌区量测控设... 大中型灌区供水服务应全面考虑水资源的流动性、循环性、系统性等自然属性,从系统治理的视角,统筹考虑灌区上下游、左右岸、地表地下等水流全过程的配置效率。针对目前大中型灌区量测水设施在建设布局中的常见问题,提出了灌区量测控设施整体规划要点,研究了灌区量测控设施总体布局考量因素,提炼了渠道量测控设施现场布置模式,以期实现灌区灌溉用水的高效配置和节约集约利用,可为大中型灌区量测控设施建设整体规划和总体布局提供参考。 展开更多
关键词 大中型灌区 测量 整体规划 布局模式
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基于概率增益模型的强震概率预测研究
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作者 钱晓东 贺素歌 《地震研究》 CSCD 北大核心 2024年第2期223-232,共10页
为提高云南地区及邻区强震中短期预测的准确度,通过强震发生前不同地震前兆指标的对比研究,发现仅用单项指标很难提高预测的准确度。挑选出能从不同侧面反映强震发生规律的6项指标,采用概率增益模型对这些指标进行综合处理,通过估算每... 为提高云南地区及邻区强震中短期预测的准确度,通过强震发生前不同地震前兆指标的对比研究,发现仅用单项指标很难提高预测的准确度。挑选出能从不同侧面反映强震发生规律的6项指标,采用概率增益模型对这些指标进行综合处理,通过估算每种地震前兆的概率增益来定量判定地震发生的可能性,最终得到可用来预测云南地区及邻区M≥6.0地震未来中短期发生可能性大小的综合概率P指标。计算分析表明:①使用综合概率P预测未来半年云南地区及邻区M≥6.0强震,能通过R值检验;②取P异常阀值为20%、30%,可对强震进行不同级别预警,P值小于20%为安全,P值为20%~30%为黄色预警,为云南地区及邻区未来存在发生M≥6.0地震的可能性;P值大于30%为红色预警,表示未来半年云南地区及邻区将发生M≥6.0地震。 展开更多
关键词 概率增益模型 综合概率 中短期预测 云南地区及邻区 M≥6.0地震
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1991—2020年新疆中小湖泊面积变化时空特征及趋势分析
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作者 马元植 覃小林 +2 位作者 凌红波 闫俊杰 张广朋 《干旱区研究》 CSCD 北大核心 2024年第6期905-916,共12页
湖泊作为陆地生态系统中的关键组成部分,是区域经济发展和生态安全的重要保障。本研究分析了1991—2020年间新疆地区74个中小湖泊的面积动态,对不同海拔和地理特征的湖泊进行了综合分析。研究发现,1991—2020年间,新疆湖泊总面积从167.9... 湖泊作为陆地生态系统中的关键组成部分,是区域经济发展和生态安全的重要保障。本研究分析了1991—2020年间新疆地区74个中小湖泊的面积动态,对不同海拔和地理特征的湖泊进行了综合分析。研究发现,1991—2020年间,新疆湖泊总面积从167.98 km^(2)增加至400.51 km^(2),尤以山区湖泊面积增长最为显著。月度尺度分析山区湖泊面积变化具有明显的季节性特征。统计分析显示,新疆不同海拔的湖泊对气候变化的响应各异。新疆山区湖泊面积显著扩大,主要受气候变化的影响,尤其是年均温度上升。在平原湖泊区域,人类活动(特别是灌溉)是湖泊面积变化的主要驱动因素,而气候因素的影响则相对较小。 展开更多
关键词 中小湖泊 面积变化 遥感监测 新疆
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考虑变形/侵蚀耦合的弹体横截面积理论模型
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作者 徐恒威 卢永刚 +2 位作者 李军润 冯晓伟 卢正操 《兵工学报》 EI CAS CSCD 北大核心 2024年第S01期97-104,共8页
弹体以中高速侵彻混凝土介质时,弹靶之间的高压作用导致弹体出现严重变形。同时,剧烈的摩擦作用使得弹体质量出现侵蚀,进一步导致侵彻性能显著下降。为深入研究中高速条件下弹体的侵彻行为,基于空穴膨胀理论和Alekseevskii-Tate模型,分... 弹体以中高速侵彻混凝土介质时,弹靶之间的高压作用导致弹体出现严重变形。同时,剧烈的摩擦作用使得弹体质量出现侵蚀,进一步导致侵彻性能显著下降。为深入研究中高速条件下弹体的侵彻行为,基于空穴膨胀理论和Alekseevskii-Tate模型,分别获得侵彻模式转变时对应的临界速度。在此基础上,考虑中高速侵彻下弹体变形和质量侵蚀的耦合效应,进而构建中高速侵彻下弹体横截面积的理论模型。为验证理论模型的合理性及可靠性,与文献实验数据进行对比分析。实验结果表明:临界速度理论模型的预测结果与文献[6,11]实验数据吻合较好,证明了模型的准确性。中高速侵彻下弹体在变形、侵蚀效应的共同作用下,侵彻后横截面积随初始撞击速度近似呈指数增大。变形效应导致弹体镦粗,侵蚀效应使得弹体表面材料被逐渐剥落。 展开更多
关键词 中高速侵彻 弹体变形 质量侵蚀 临界侵彻速度 横截面积
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不同驱替介质在演23区延7储层中的应用
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作者 索步森 卞小强 +3 位作者 曾永平 王雪艳 何万春 张全培 《非常规油气》 2024年第3期107-113,共7页
针对演23区油藏目前存在水驱油效率、单井产量及采出程度普遍较低的问题,急需开展控水稳油技术攻关,减缓含水上升速度,探索新注入介质,提高驱油效率,提高最终采收率。选取主力产油层位延7储层样品开展不同驱替介质的室内实验,并根据实... 针对演23区油藏目前存在水驱油效率、单井产量及采出程度普遍较低的问题,急需开展控水稳油技术攻关,减缓含水上升速度,探索新注入介质,提高驱油效率,提高最终采收率。选取主力产油层位延7储层样品开展不同驱替介质的室内实验,并根据实验结果进行现场先导性试验论证。结果表明:纯水驱平均驱油效率为45.45%,驱油效率延7_(1)高于延7_(2),结合核磁共振实验可知孔喉半径及分布规律对驱油效率影响较大;相较单纯水驱,水驱后转氮气驱、聚合物驱或表面活性剂驱的驱油效率均有一定程度的增加,其中,聚合物驱油效率增加最高,为38.72%,氮气驱次之,增加16.20%,表面活性剂驱最低,只增加4.39%,且延7_(2)储层驱油效率提高大于延7_(1)储层;现场开展聚合物驱先导性试验,表现出地层压力上升、增产降水、见效比高,与驱油实验结果较相符,整体表现为研究区对聚合物驱的适应性较强。研究结论对于研究区后期现场高效开发具有指导性意义。 展开更多
关键词 演23区 驱替介质 提高采收率 驱油效率
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滇南一次暖区暴雨过程的雷达反演风场分析
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作者 高正南 杨素雨 +1 位作者 王飞 业红伟 《云南大学学报(自然科学版)》 CAS CSCD 北大核心 2024年第4期709-719,共11页
利用自动气象站资料、ERA5再分析资料、探空资料和CINRAD/CC普洱天气雷达数据等多源资料,对2020年8月7日滇南大暴雨过程进行天气尺度和中小尺度系统综合分析.结果表明:①此次强降水是典型的暖区暴雨过程;②500 hPa东风波和700 hPa低涡... 利用自动气象站资料、ERA5再分析资料、探空资料和CINRAD/CC普洱天气雷达数据等多源资料,对2020年8月7日滇南大暴雨过程进行天气尺度和中小尺度系统综合分析.结果表明:①此次强降水是典型的暖区暴雨过程;②500 hPa东风波和700 hPa低涡系统是主要的影响系统,200 hPa高空辐散特征加强了低层系统的发展;③本次过程发生在高湿、高能、强垂直运动的大气环境背景下,孟加拉湾低压为滇南局地强降水提供充足的水汽,水汽通量散度强度达-4.6×10^(-6) g·cm^(-2)·hPa^(-1)·s^(-1);副高在滇南地区向北凹陷有利于不稳定能量积累,∑θ_(se)≥260℃的区域与地面6 h强降水落区对应一致;特大暴雨发生期间伴随有能量和强暖平流输送;④中尺度对流系统生命史完整且漫长,回波原地生消,中心稳定少动,“列车效应”明显,低质心暖云回波贡献了短时高效的降水,导致地面降水持续时间长、强度大、落区局地性强;对流发展旺盛阶段存在明显小尺度次级环流和水平气旋式辐合,二者投影位置一致,呈现出对流系统三维立体运动特征;地面投影附近集中出现20 mm·h^(-1)以上短时强降水,最大78.6 mm·h^(-1);⑤滇南地形对东(抬升)、西(降低)两股气流截然不同的影响加剧了辐合区垂直运动发展,在“喇叭口”地形隔挡下两股气流长时间交汇对峙,为特大暴雨的形成提供了有利的地形条件. 展开更多
关键词 暖区暴雨 天气诊断 雷达风场三维变分反演 中小尺度系统 地形 滇南地区
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