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Search Results: 1 - 10 of 19348 matches for " 贾非 "
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1991~1995年大连市饮服行业人员检出结核病的动态分析
迟美华,
中国公共卫生 , 1996,
Abstract: ?我们对大连市1991~1995年饮服行业人员检出结核病进行了动态分析.现将结果报告如下.
泥岩巷道围岩弹塑性参数反演分析与长期稳定性预测
,善坡
岩土力学 , 2014,
Abstract: 以实测的围岩蠕变变形资料为基础,基于现场监测所获得的蠕变本构模型,对某一矿区泥岩体的力学参数进行了弹塑性反演分析,得到的巷道围岩体基本力学参数分别为弹性模量e=2.0gpa,凝聚力c=1.31mpa,内摩擦角?=24o。待反演参数水平均值的极差结果显示,通过极差的大小可以判断岩土力学参数的敏感性,对蠕变的影响而言,凝聚力最敏感,其次是内摩擦角,弹性模量再次之。在此基础上,利用反演所得的围岩基本力学参数进行了正演,计算得到了各测点处对应的蠕变位移增量,与实测值相比吻合较好,表明反分析所获得的岩体材料参数综合反映了巷道围岩的力学特性。最后,对巷道围岩变形大小及塑性区范围进行了预测。
引入补偿策略的风险共担配送中心选址问题研究
,王丽萍,
公路交通科技 , 2010,
Abstract: 在LMRPVCC问题优化模型基础上,在目标函数与约束条件中引入运输补偿成本项及服务半径Dr,将模型扩展为引入补偿策略的LMRPVCC选址-库存问题的非线性整数规划模型。利用所设计的粒子群算法对Daskin和Shen的文章中的49节点、88节点算例求解,并对补偿系数W、服务半径Dr及运输成本系数β进行敏感性分析,认为服务半径Dr越小,超出服务半径的零售商数量越多,配送中心需额外支出的补偿费用越高;服务半径Dr越大,超出服务半径的零售商数量越少,配送中心需支出的补偿费用越少。补偿成本系数W、运输成本系数β与模型目标函数值正相关。
冬季白马鸡群体夜栖地特征分析
,王楠,郑光美
生态学杂志 , 2005,
Abstract: ?2003年1~4月,对分布于四川省甘孜藏族自治州稻城县著杰寺周围的白马鸡(crossoptiloncrossoptilon)群体的夜栖地特征进行了分析.随机跟踪黄昏时发现的白马鸡群体直至其上树夜栖来确定夜栖地的位置.通过系统取样的样线法调查整个研究区域环境变量的特征.共获得172个200m×200m的栅格,栅格中有夜栖地出现的定义为活动栅格(37个),赋值为1;反之为非活动栅格(135个),赋值为0.通过逻辑斯蒂回归建立白马鸡群体夜栖地选择的预测模型.该模型的数学表达式为ln[p/(1-p)]=-3.938+0.083×坡度+0.037×乔木盖度+0.11×乔木高度-0.003×草本盖度(p为白马鸡群体夜栖地的出现概率).模型表明坡度、乔木盖度、乔木高度和草本盖度显著影响白马鸡群体的夜栖地选择.白马鸡群体的夜栖地选择与坡度、乔木盖度和乔木高度正相关,与草本盖度负相关.该预测模型具有较高的预测准确性.
幼儿数学思维能力培养
成子娟,,冯志坚
心里发展与教育 , 1990,
Abstract: 儿童思维能力培养是当今举世瞩目的重大研究课题之一。我们选择幼儿数学思维能力培养的课题作为儿童思维能力培养的一个方面和突破口,在我国具有重要的理论意义和实践价值,下面我们从四个方面来简述这项工作。
辛基三甲基溴化铵与辛基硫酸钠混合水溶液的相行为
胡尚林,,戴乐蓉
物理化学学报 , 2002,
Abstract:
科技期刊国际影响力提升初探——以《应用天然产物》为例
,刘静,田宏,吴茵杰?
中国科技期刊研究 , 2014,
Abstract: 中国科技期刊数量众多,但国际影响力有待提升。中国科技期刊国际影响力提升计划是由“六部委”联合实施的大型英文科技期刊资助项目,《应用天然产物》获2014年该计划d类支持。《应用天然产物》在期刊管理体制、办刊机制和模式、资金投入方式、办刊人才组成、科研政策支持等方面进行了有益探索。
狐尾藻对园林水景污染水体的净化作用
Purification Function of Myriophyllum on Contaminated Gardening Waterscape

,袁涛,马映东
- , 2015, DOI: doi:10.3969/j.issn.1001-7461.2015.06.45
Abstract: 园林水景植物不仅能美化景观,其治理水体富营养化现象也不可忽视。利用水生植物狐尾藻净化水体污染是近年来治理水质恶化的有效生态方法。以麦积区渭河城区段水面“翠湖”为研究区域,以狐尾藻为去污材料,运用点抽样―水槽培养方法开展室外试验,试验时间在2014年6-9月。结果表明,1~60 d,水体总氮、总磷、铵态氮、化学需氧量浓度整体呈下降趋势,而试验后期水体出现轻微的反弹污染;试验期始末,表层水体营养物质含量较底层的低。狐尾藻生命力强,适宜条件下繁殖速度较快。为防止狐尾藻后期腐烂,水体二度污染,保证狐尾藻去污时间相对持久,需对狐尾藻定期采割。
While beautifying the waterscape, the application of aquatic plants can also control the contamination of the waters where they grow due to eutrophication. Myriophyllum is one of such plant species used recently. Taking “Cuihu Lake” in Maiji District of Tianshui, Gansu Province as research object, Myriophyllum was adopted to control water contamination from June to September in 2014. After the application of myriophyllum, the contents of total nitrogen(TN), total phosphorus (TP), ammonium nitrogen (NH4+-N), chemical oxygen demand (COD) decreased during 1 to 60 d of the application. Slight rebound water pollution was observed in the later stage of experiment. The nutrient contents in surface water were lower than the deep one at the early stage. Myriophyllum has a strong vitality and breeds rapidly under suitable conditions. In order to ensure the function time of myriophyllum relatively longer, the decomposition and the second pollution of water must be avoided, therefore, it is imperative to collect newly grown myriophylum regularly
内积空间与最小二乘法
Inner Product Space and the Least Square Method
 [PDF]


Pure Mathematics (PM) , 2013, DOI: 10.12677/PM.2013.31011
Abstract:
最小二乘法在一般的线性代数中存在标准的推导过程。本文从内积空间的结构出发去发现最小二乘法的本质问题,并且给出了最小二乘法取值的快速算法。同时我们给出了在内积空间中多个点到子空间的最小距离的求法,这是对一般最小二乘的延托。The least square method has a standard method in most of books about linear algebra. In this paper we introduce the element definitions of inner product space and the standard least square method. And in this document we also give a fast calculation for the least square method in inner product space. In the least part we give a method for calculating the smallest distance of the sum of finite points to a subspace. This is an extension for the least square method.
强化污泥厌氧消化性能的预处理技术研究进展
Progress in the Pretreatment of Sludge Anaerobic Digestion
 [PDF]


Sustainable Development (SD) , 2016, DOI: 10.12677/SD.2016.63017
Abstract:
随着我国城市污水处理厂污水处理量的逐年增加,剩余污泥产量也日益增大,导致其处理处置难。污泥因为其含水率高、富含有机质及病原体,在处理处置之前,必须进行稳定化处理。厌氧消化是污泥稳定化的常用技术,特别是针对大中型污水处理厂,并且可以通过产甲烷,实现能源回收。但由于细胞壁的存在,使得污泥水解成为厌氧消化的重要限速步骤。通过一定的预处理作用,可有效地提高细胞壁的破解效率,促进胞内有机物的溶出,大幅缩短污泥厌氧消化周期,提高污泥厌氧消化性能。本文综述了污泥厌氧消化预处理的各种主要技术的优缺点,包括生物处理、热水解、机械处理、化学氧化处理和碱处理等技术。目前研究的重点主要集中在预处理后污泥的性质变化及产甲烷性能的改善方面。
With the increase of wastewater treatment capacity of wastewater treatment plant in China, the production of excess sludge is increasing day by day, leading to the difficulty in treatment and disposal. The sludge must be stabilized before final disposal because of its high moisture content and rich in organic matter and pathogens. Anaerobic digestion is a common technology for sludge stabilization, especially for large and medium sized wastewater treatment plants, and can be used for production of methane to achieve energy recovery. However, because of the presence of the cell wall, the hydrolysis of sludge is key limited step of anaerobic digestion rate. The pretreatment technologies of sludge can effectively enhance the damage of the cell wall, promoting the intracel-lular organic matter releasing into aqueous phase, improving the sludge anaerobic digestion per-formance. The advantages and disadvantages of various pretreatment technologies of sludge an-aerobic digestion were reviewed in this study, including biological treatment, thermal hydrolysis, mechanical treatment, chemical oxidation treatment and alkali treatment. At present, the research focuses on the characteristics of the sludge after pretreatment and the improvement of methane production.
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