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Search Results: 1 - 10 of 61404 matches for " 向书杰 "
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基于时频原子灰色关联的小电流接地故障选线方法
王晓卫,侯雅晓,,李玉东,,
煤炭学报 , 2014,
Abstract: 提出一种时频原子灰色关联的小电流接地故障选线方法。根据当前小电流接地系统分支线路数目,计算故障线与非故障线的线路基准值;以Gabor原子库为索引,利用匹配追踪法将各分支线路故障后首个1/4周期内的暂态零序电流进行时频原子分解,求得表征各分支线路故障特征信息的衰减正弦量原子;采用改进灰色关联分析对各衰减正弦量原子进行关联度分析,求得各分支线路的特征值;将各特征值分别与故障线和非故障线的基准值求欧式距离并比较大小,通过所求欧式距离大小的比较,可实现准确选线。仿真结果表明,该方法计算量小,选线精度高,尤其适用于多分支线路的小电流接地系统。
纳米纤维素基导电材料及其在电子器件领域的研究进展
杨全岭,杨俊伟,石竹群,,熊传溪
- , 2018, DOI: 10.13360/j.Issn.2096-1359.2018.03.001
Abstract: 为了应对全球日益严重的环境污染和资源短缺,近年来,可再生、环境友好的生物质材料受到越来越多的关注。纤维素是地球上产量最大的生物质,在自然界中分布广泛且含量丰富,具有资源优势的同时还具有可生物降解、无毒等优点。纳米纤维素是一种可通过物理、化学或生物方法从原纤维中分离出的直径为纳米级的纤维素材料,其优异的力学、光学和热稳定性使其在电子器件领域具有广阔的应用前景。纳米纤维素结构的基本属性对其在新兴应用设计和产品制造上至关重要。因此, 笔者在介绍纳米纤维素不同维度结构的基础上,对纳米纤维素基导电材料制备过程中的改性和炭化处理研究进展,以及其在电子、储能器件领域所取得的应用研究进展进行了综合评述,并对其在应用过程中存在的问题进行了分析。最后,就纳米纤维素基导电材料未来应用研究的重点和方向阐述了自己的观点, 认为应该在降低纳米纤维素材料的制备成本以提高纳米纤维素的生产效率,以及开发既能方便储存运输又不会导致纳米纤维素聚集的新方法等方面加强投入。
In response to the global increasingly severe environmental pollution, resource shortage, and ecological damage, which have severely affected human's activity and health, in the past 40 years, renewable and environment-friendly biomass materials, such as cellulose, starch, soy protein isolate(SPI), lignin, and chitin, have received more and more attention. Cellulose is the most abundant biomass on earth and widely distributed in nature. It has the advantages of renewability, non-toxicity, biocompatibility, biodegradability, and derivable properties. Therefore, the cellulose is promising to be used as the potential replacement for petroleum-derived synthetic polymer plastics, which are non-biodegradable or carbon neutral and non-renewable. Nanocellulose is nanosized cellulose material that can be obtained from the physical, chemical, or biological treatment of cellulose fibrils. The nanocelluloses have recently attracted attention as nano-sized and bio-based materials prepared from abundant biomass resources. They are roughly categorized as cellulose nanofibrils(CNFs)and cellulose nanocrystals(CNCs)with high and low aspect ratios, respectively. The high mechanical strength and modulus, low coefficient of thermal expansion, superior gas-barrier properties, and high electrical resistivity make nanocellulose attractive in the application as electronic devices. Furthermore, the basic structures and properties of the nanocellulose are crucial to their design and manufacturing of products for emerging applications. Therefore, based on the introduction of the different dimensions and structures of the nanocellulose, this paper reviews the preparation of nanocellulose-based conductive materials, as well as their applications in the fields of electronic and energy storage devices. Two main methods commonly used to prepare nanocellulose-based conductive materials are modifing the nanocellulose with conductive materials, such as polyacetylene, polypyrrole(PPy), polyaniline(PANI), polythiophene(PTh)carbonizing the nanocellulose materials to make them conductivity. Moreover, two critical applications of nanocellulose-based materials are also
一类新的双层纺织材料厚度设计反问题
A New Inverse Problem of Thickness Design for Bi-Layer Textile Material
 [PDF]


Advances in Applied Mathematics (AAM) , 2013, DOI: 10.12677/AAM.2013.22012
Abstract:

本文基于低温环境下平行圆柱孔结构的纺织材料热湿传递稳态模型,研究了一类双层纺织材料厚度设计反问题。首先给出了一个双层纺织材料热湿传递稳态模型,并采用有限差分方法求解该问题。然后,根据服装热湿舒适性指标,将纺织材料内层厚度看成一个未知量,提出了一类双层纺织材料厚度设计反问题,将该反问题归结为一个最大概率最小模问题,采用罚函数法将该约束优化问题转换为无约束的优化问题,并采用粒子群算法求解。数值结果说明了双层纺织材料厚度设计反问题提法的合理性,以及粒子群算法的有效性和鲁棒性。
This paper studies a new inverse problem of estimating bi-layer textile fabrics thickness based on a steady-state heat and moisture transfer model. We first present a heat and moisture transfer model for bi-layer textile materials with boundary conditions and solve them by finite difference method. According to the requirement of clothing’s thermal and moisture comfort, we formulate the inverse heat and moisture transfer problem that estimate the thickness of inner fabric as a minimum norm problem with a maximum probability constraint model. We use a static penalty method to convert the constrained problem into an equivalent unconstrained minimization problem and obtain the solution for the optimization problem by a stochastic search method, known as particle swarm optimization algorithm. Numerical experiments show that our new model is quiet acceptable, and the proposed numerical method’s validity and robustness.

富硒绿茶对大鼠非酒精性脂肪肝ca2+-atpase活性和表达的影响
王凤,陈显兵,,谭志鑫,国敏,刘锦红
食品科学 , 2014,
Abstract: ?目的:研究恩施富硒绿茶对大鼠非酒精性脂肪肝病(nonalcoholicfattyliverdisease,nafld)中肝脏肌浆网/内质网ca2+-atpase(sarco(endo)plasmicreticulumca2+-atpase,serca)活性及其表达的影响,探讨富硒绿茶防治nafld的可能作用机制。方法:将32只wistar大鼠分成4组,分别饲喂标准饲料+常规饮水(nc组)、高脂饲料+常规饮水(hc组)、高脂饲料+普通绿茶(tc组)、高脂饲料+富硒绿茶(sec组)。9周后处死,观察大鼠一般情况,测定肝细胞内ca2+含量、肿瘤坏死因子-α(tumornecrosisfactor-α,tnf-α)水平、肝脏组织atpase活性;采用免疫组化染色和westernblotting检测肝脏内总serca蛋白表达,观察各指标变化情况。结果:hc组大鼠肝细胞内ca2+含量明显增高,na+-k+-atpase、ca2+-atpase活性降低,serca蛋白表达降低;富硒绿茶干预后ca2+含量降低,酶活性升高,表达增加,较普通绿茶效果明显。结论:富硒绿茶对高脂饮食诱导的大鼠非酒精性脂肪肝病具有干预作用,可能是通过降低肝细胞内ca2+和tnf-α含量而改善肝脏能量代谢障碍,同时提高了serca活性,增强其蛋白表达而实现的。
1982~2010年京津冀地区气候背景与变化特征分析
Analysis of Climate Background and Characteristics in Beijing-Tianjin-Hebei Region during 1982-2010
 [PDF]

, 吴云龙, , 牛树倩
Climate Change Research Letters (CCRL) , 2014, DOI: 10.12677/CCRL.2014.34024
Abstract:
根据京津冀地区近29年(1982~2010年)83个气象站点的月平均气温和月降水量数据,运用趋势分析、突变检验、经验正交函数(EOF)分解等方法,研究了该地区气温和降水时空变化特征。结果表明:1) 京津冀地区气温空间分布差异较大,近29年研究区平均气温年际变化整体呈增加趋势,1993年为气温突变年;各季气温均呈上升趋势,其中冬季上升趋势最为明显,其次是春季和夏季,秋季上升趋势最小。2) 降水量空间分布不均,年降水量整体呈下降趋势,年际波动较大;四季中,夏季呈减少趋势,其他季节均为弱的增加趋势。3) EOF分析表明,整个研究区气温空间分布呈一致性变化,气温明显增加的区域位于中西部地区,1983~1987年为下降趋势,1988年以后呈增加趋势,特别是1993年以后气温增加显著;降水空间分布差异较大,且存在较大的年际变化,1997年以前以增加为主,1998~2002年为偏少期,2003年以后降水增加。
According to the data of Beijing-Tianjin-Hebei region in recent 29 years (1982-2010) of 83 me-teorological stations in the monthly average temperature and monthly precipitation, using trend analysis, mutation test, the empirical orthogonal function (EOF) method, the characteristics of temperature and precipitation change were studied. The results showed that: 1) The difference of spatial distribution of temperature in Beijing-Tianjin-Hebei region is big. In the recent 29 years, the average annual temperature variation has increased. In 1993, there was an abrupt change in temperature. Seasonal temperature was rising, and the upward trend in winter was the most ob-vious, followed by the spring and summer. The rise in autumn was the minimum. 2) Precipitation was uneven according to spatial distribution; the overall annual precipitation showed a decreasing trend; the interannual fluctuation is big. In the four seasons, precipitation in summer was de-creasing, and that in other seasons was weakly increasing; 3) EOF analysis showed that in the study area, the spatial distribution of temperature was consistent with changes in temperature. In the central and western regions, the temperature increased obviously; however, from 1983 to 1987, it declined; it showed an increasing trend after 1988, especially after 1993. The difference in spatial distribution of precipitation was big, and there were large interannual variations. Before 1997, the precipitation mainly increased; from 1998 to 2002, it increased less; after 2003 it increased again.
留置导尿管相关性尿路感染目标监测结果与分析
,刘萍
华西医学 , 2013, DOI: 10.7507/1002-0179.20130367
Abstract: 目的 了解留置导尿管相关性尿路感染发生率,为制定预防控制措施提供参考依据。方法 2012年3月-8月在神经内科、神经外科、老年内科、泌尿外科对留置导尿管的患者进行医院感染目标性监测。结果 导尿管相关尿路感染发病率为6.46%,感染率最高的科室为老年内科13.95%,其次为神经外科12.96%和泌尿外科3.59%。神经内科导尿管0.00%。结论 针对监测结果,采取适当的干预措施,可有效降低留置导尿管相关性感染的发生率。
论马克思主义内含着的社会和谐思想
自强,军?
天府新论 , 2005,
Abstract: 马克思主义的社会和谐思想,是辩证唯物主义和历史唯物主义的和谐思想。社会生活实践是社会和谐的基础和纽带,社会和谐是社会进步和人类文明的和谐,是人与自然界关系的和谐。马克思主义的社会和谐思想是构建社会主义和谐社会重要的世界观和方法论。
政府资产负债表的核算主体范围研究
罗胜,
中央财经大学学报 , 2017,
Abstract: 摘要 编制政府资产负债表对于政府资产负债存量核算具有重要意义。政府资产负债表编制相关问题亟待突破解决,核算主体范围是首要问题。笔者围绕政府范围的规范统一问题开展探索性分析。笔者分析认为:编制目的是确定编制政府资产负债表理论基础的重要依据,政府活动属性决定了政府资产负债表的编制理论基础,将SNA体系、GFS体系与IPSAS准则结合起来,有利于政府范围的规范统一。在此基础上,笔者通过比较分析三种不同核算体系中的政府范围,发现GFS体系多层次政府范围划分有助于政府范围界定的规范化。结合中国组织机构的活动属性和功能,将中国政府资产负债核算主体范围划分为三个层次,能够实现编制政府资产负债表的目的。
综合医院多重耐药菌目标性监测与分析
Monitor and analysis of multi-drug resistant organisms in general hospitals

刘萍,
- , 2015,
Abstract: 摘要:目的 监测多重耐药菌(MDRO)流行特征及医院内分布,分析其耐药性以控制医院内感染。方法 采用目标监测方法对2013年1-12月检出6种MDRO的监测情况进行分析。结果 共分离出病原菌3 194株,其中MDRO 1 911株,目标监测的MDRO 516株,占27.0%(516/1 911),包括产超广谱β-内酰胺酶(ESBLs)的大肠埃希菌52.1%(214/411)和肺炎克雷伯菌16.0%(119/744)、耐甲氧西林金黄色葡萄球菌16.1%(42/261)、耐万古霉素肠球菌(0%)、耐碳青霉烯类鲍曼不动杆菌38.9%(84/216)及多耐药铜绿假单胞菌20.4%(57/279);主要分布在ICU(18.9‰)、肿瘤科(4.9‰)、儿科(4.5‰)、呼吸内科(3.6‰);MDRO医院感染占17.6%(91/516);产-ESBLs的大肠希菌和肺炎克伯菌对阿米卡星、头胞替坦及β-内酰胺酶抑制剂的复方抗生素制剂、碳青霉烯类有较高敏感性。大肠埃希菌对头胞唑啉、头胞曲松耐药;鲍曼不动杆菌对亚胺培南耐药率为25.2%;铜绿假单胞菌耐药性严重;金黄色葡萄球菌对利奈唑胺、万古霉素全部敏感。结论 应加强对MDRO的监管尤其是社区的MDRO的监管,合理使用抗菌药物,控制耐药性的增加,防止MDRO医院内感染。
家电行业上市公司财务报表综合分析——以白色家电板块为例

财会月刊 , 2011,
Abstract:   本文重点对白色家电板块的8家上市公司2009年的财务报表进行综合分析,分别从企业的盈利能力、偿债能力、营运能力等进行评价,并对如何改善家电行业财务管理和财务状况提出了一些建议。  【关键词】家电行业白色家电上市公司财务报表  家电行业的发展在我国经济发展中具有重要的标杆作用,是当今我国市场化程度最高、竞争最激烈的行业。《中国家用电器工业“十二五”发展规划的建议》提出从家电大国向家电强国转变的目标。“家电强国,白电先行”,白电即白色家电,是我国家电行业中最具竞争力的子行业,总体来看,其已经具备初步的全球竞争力。以海尔冰箱、洗衣机,格力U型超薄空调为代表的中国白电产品已经开始争夺全球高端市场。但最近几年,科龙、创维等家电企业出现的财务危机已反映出我国家电行业内部仍存在诸多经营与财务上的问题。企业若能及早发现这些财务问题,就可以避免破产倒闭的风险。本文从投资者的角度对我国家电行业8家上市公司2009年的财务报表进行综合分析,并提出相应的改进建议。  一、数据选择  本文重点选取了白色家电板块(以下简称“白电板块”)的8家具有代表性的公司2009年的财务数据,它们分别是格力电器、美的电器、青岛海尔、美菱电器、合肥三洋、小天鹅A、澳柯玛、ST科龙。
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