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金 属 改 性 的Pd / γ Al2 O3 催 化 剂 在 转 移 加 氢 中 的 应 用  [PDF]
郑纯智,张国华,赵德建,张春勇,文颖频
分子催化 , 2009,
Abstract: 研 究 了 Cu、 La、 Ba、 Ce 和 Co 等 多 种 金 属 氧 化 物 对 Pd / γ Al2 O3 催 化 剂 在 3, 5 二 羟 基 苯 甲 酸 转 移 加 氢 制 备3, 5 二 氧 代 环 己 烷 羧 酸 反 应 中 的 活 性 影 响 , 发 现 镧 的 改 性 效 果 最 明 显 . 得 到 的 Pd LaOx / γ Al2 O3 催 化 剂 在 150 ℃下 还 原 , 催 化 3, 5 二 羟 基 苯 甲 酸 转 移 加 氢 反 应 的 转 化 率 和 选 择 性 分 别 达 到 了 90. 6% 和 98. 2% . 在 150 ℃ 下 PdCl2被 还 原 为 Pd, 而 La 保 持 氧 化 态 . 经 TPR、 SEM、 TEM、 XPS 等 手 段 分 析 后 认 为 , 引 入 的 La 使 Pd 具 有 适 宜 的 粒 度 ,低 温 还 原 时 保 持 氧 化 态 的 La 与 载 体 产 生 相 互 作 用 , 并 对 Pd 的 转 移 加 氢 活 性 的 提 高 有 利 , 而 高 温 下 被 还 原 的 La则 对 提 高 Pd 的 活 性 不 利 .
热处理对卵转铁蛋白抑菌效果的影响  [PDF]
唐清,刘枫,周蓓,杨严俊,苏宇杰
- , 2017, DOI: 10.3969/j.issn.1673-1689.2017.03.008
Abstract: 卵转铁蛋白(OVT)是一种具有结合铁能力的球蛋白,具有广谱的抗菌功能,其抑菌活性与其结构密切相关。作者研究热处理对卵转铁蛋白抑菌效果的影响,并通过对其二级结构和疏水作用的分析来揭示其抑菌效果的变化机理。结果表明:随着处理温度的升高,卵转铁蛋白对沙门氏菌和大肠杆菌的抑菌效果呈降低趋势;热处理后卵转铁蛋白的二级结构和疏水作用都发生了变化,随着处理温度的升高以及处理时间的延长,α-螺旋含量呈降低趋势,β-折叠含量呈升高趋势,表面疏水性明显增大,而热处理时间则与卵转铁蛋白的结构与活性明显关联。
Ovotransferrin, an iron-binding globulin, had a broad spectrum of antibacterial activity. Its antibacterial activity was closely related with its structure. In this study, the impact of heat treatment on the structure and antibacterial activity of ovotransferrin was studied, and the change mechanism of the antibacterial effect was revealed through the analysis of its secondary structure and hydrophobic effect. Results showed that the antibacterial activity of ovotransferrin on Escherichia coli and Salmonella was decreased with the increase of treatment temperature. The structure of ovotransferrin got changed after the heat treatment, the contents of α-helix and random coil of ovotransferrin were decreased due to the high temperature, meanwhile the contents of β-sheet and the β-turn were increased. Besides, surface hydrophobicity of ovotransferrin was significantly increased. As processing time extension, the antibacterial activity of ovotransferrin had no significant change at the same temperature
一移两转平板折展柔性铰链的建模及优化  [PDF]
刘凯,曹毅,周睿,葛姝翌,丁锐
- , 2017, DOI: 10.3785/j.issn.1008-973X.2017.12.012
Abstract: 为提高平板折展机构(LEMs)的灵活性,提出一种一移两转三自由度平板折展柔性铰链.综合考虑各柔性片段的变形特点,设计一移两转平板折展柔性铰链的外形结构;利用等效弹簧模型推导该铰链沿x轴、y轴方向的转动等效刚度及沿x轴方向的移动等效刚度的理论计算模型,并通过设计实例的理论计算结果和仿真分析结果对比,验证刚度计算模型的正确性;探讨各结构参数对3种等效刚度的影响灵敏度;以提高铰链的转动性能和移动性能为目标,构建一移两转平板折展柔性铰链的多目标加权优化模型,并利用基于罚函数的粒子群算法对各结构参数进行优化.结果表明:优化后的一移两转平板折展柔性铰链的各项性能都有较大提升,优化模型具备可行性.
Abstract: A new one-translational and two-rotational lamina emergent mechanisms (LEMs) flexure hinge with three degrees of freedom was presented in order to increase the flexibility of LEMs. The configuration of one-translational and two-rotational LEMs flexure hinge was designed considering the deformation feature of compliant fragments. The theoretical models of two equivalent rotational stiffness around x-axis and y-axis and one equivalent translational stiffness along x-axis were deducted. By comparing the theoretical calculation results with finite element simulation results of the design example, the validity of the theoretical calculation models was proved. The sensitivy of impact of structural parameters on the three kinds of equivalent stiffness was discussed in detail. In order to enhance the rotational capacity and mobility ability of the one-translational and two-rotational LEMs flexure hinge, a multi-objective optimization model was constructed, and the structural parameters were optimized based on particle swarm algorithm with penalty function. Results show that the properties of the one-translational and two-rotational LEMs flexure hinge are improved significantly and the optimization model is feasible.
露天转地下过渡期岩移危害控制方法  [PDF]
李海英,任凤玉,严国富,赵云峰
- , 2015, DOI: 10.12068/j.issn.1005-3026.2015.03.026
Abstract: 摘要 在露天转地下过渡期,由于露天地下同时生产的岩移干扰,经常导致安全生产条件差和产量衔接困难.针对露天转地下过渡期露天开采境界内底部矿量、地下开采挂帮矿的实际生产条件,系统地研究了地下开采与岩移特点,提出了应用诱导冒落技术控制挂帮矿地采岩移的方法,不仅改善了露天地下安全生产条件,而且扩展了露天地下同时开采时间与空间.这一方法应用于小汪沟铁矿,有效解决了露天转地下过渡期产量衔接的难题,并实现了安全高效开采.
Abstract:Due to mutual interferences between the open pit & underground mining operations during the transition period from open pit to underground mining, poor safety production and difficult production continuation occur much more frequently. Aiming at the production conditions of ore-body at the open pit bottom and hanging-wall ore-body of underground mining during transition period, a method was proposed to control the hanging rock caving with the induced caving mining technology through the systematic study on the underground mining and rock caving. In this way, the safety conditions of open pit & underground mining could be improved, and the time and space of open pit & underground mining are also extended. The proposed method was adopted in Xiaowanggou Iron Mine to solve the problem of production discontinuation. The applied results show that a highly efficient and safe mining is realized during the transition from open pit to underground mining.
涡流空气分级机转笼结构对其分级性能的影响  [PDF]
刘圣照,刘家祥,冯永国,王奎升
化工学报 , 2007,
Abstract: :研究了涡流空气分级机底盘开口与封闭两种型式的转笼对分级指标的影响。重质CaCO3物料试验表明:采用底盘开口转笼时,切割粒径小,分级精度低;随着分级转速增加,切割粒径对风速的敏感性下降。另外,用激光多普勒测速计测量了上述两种转笼结构的分级机环形区的流场特性,结果表明:转笼底盘开口,环形区气流出现旁路,进入转笼径向风速减小,造成分级物料切割粒径减小;底盘封闭的分级机环形区内靠近转笼处,切向风速突变增大,特别是轴向上湍流度的增大,有利于团聚物料的分散和分级精度的提高。
短小芽胞杆菌DX01菌株Tn5转座突变株的抑菌活性筛选体系的建立  [PDF]
胡晓璐,陈云鹏,沈新迁,刘通,顾振芳
植物保护学报 , 2012,
Abstract: 为建立短小芽胞杆菌BacilluspumilusDX01菌株的Tn5转座突变株抑菌活性的高效筛选体系,采用发酵液平板抑菌法研究了各突变株发酵液对稻瘟病菌Magnaporthegrisea生长的影响,并测定了目标突变株的几丁质酶和蛋白酶活性及发酵液对稻瘟病菌分生孢子萌发的抑制率。从2633个突变株中筛选出6个抑菌活性较对照菌株DX01显著变化的突变株。对照DX01发酵液对真菌孢子萌发的抑制率为36%,而突变株Tn5-901和Tn5-194则分别为96%和3%,抑菌活性与对照的差异达到极显著水平。其余4个突变株的几丁质酶、蛋白酶活性多重比较结果与发酵液平板抑菌结果并不完全一致,但发酵液平板抑菌法简单、高效,适用于短小芽胞杆菌突变株的抑菌活性初筛。
中间移热式非定态SO_2转化器(Ⅰ)──转化器性能与操作条件的关系  [PDF]
王辉,肖博文,袁渭康
化工学报 , 1998,
Abstract: 以作者开发的可用于非定态SO2转化器模拟计算的通用软件包USSC为基础,对中间移热式与单段绝热式两种结构的非定态SO2转化器进行了比较,研究了气体组成、气速换向周期、冷却量等参数对转化器操作性能的影响.气体中SO2含量越高,床层的整体温度越高,SO2含量较高时(0.03左右),宜采用两点移热式结构的转化器.相同气体组成条件下,移波速度与气速成正比.对于两点移热式转化器,冷却量与换向周期均是可用来优化反应的操作变量,而原料气入口温度与床层预热温度对非定态转化影响较小.
小麦旗叶直立转披动态过程对其高光效的影响  [PDF]
刘永康,李明军,李景原,李晓娟,杨兴洪,童依平,张爱民,李滨,林金星,匡廷云,李振声
科学通报 , 2009,
Abstract: 以旗叶直立转披型小麦小偃81(Xy81)、旗叶直立转半披型(中间型)小偃41(Xy41)和旗叶直立型小麦小偃6号(Xy6)为材料,对旗叶的生长动态变化、解剖结构特征、光合速率、叶绿素含量、群体光合速率以及透光率等进行比较观察和测定.通过对Xy81与Xy41及Xy6进行比较结果显示,旗叶的叶片厚度、叶面积、叶肉细胞形态、叶绿体中类囊体垛叠数、光合速率和叶绿素含量等参数之间无显著区别.特别值得注意的是,Xy81的旗叶叶片生长角度在灌浆期具有明显的动态变化规律,即从直立转为下披.在此过程中,该品种的叶绿素含量无显著变化,其光合效率仍维持在较高水平,由此说明旗叶角度的变化非衰老所致.此外,在生长后期,Xy81的群体光合速率和透光率明显高于Xy41和Xy6.上述结果说明,Xy81旗叶生长的动态变化对灌浆期群体光合作用具有一定的增强效果,从而有助于小麦产量的增加.
中间移热式非定态SO_2转化器(Ⅱ)──两点移热式转化器的控制策略  [PDF]
王辉,肖博文,袁渭康
化工学报 , 1998,
Abstract: 确定了两点移热式转化器调节通道的传递函数,明确了非定态转化器是一个大时间常数的系统.将该转化器应用于某冶炼厂的尾气处理,作了三种控制方案的比较,发现阀门的双位控制较为简单,容易实现且控制效果较好.
O-GlcNAc modification: why so intimately associated with phosphorylation?
Suresh Mishra, Sudharsana R Ande, Neil W Salter
Cell Communication and Signaling , 2011, DOI: 10.1186/1478-811x-9-1
Abstract: O-GlcNAc cycling in proteins, mediated by the enzymes O-GlcNAc transferase (OGT) and O-GlcNAc amidase (OGA), is dynamically regulated in response to various stimuli and is remarkably similar to phosphorylation [1]. It has been more than 25 years since it was first discovered by Torres and Hart [2]. However, relative development in this field has remained sluggish for almost two decades, mainly due to the lack of tools and techniques for the identification and quantification of O-GlcNAc modification in proteins. As a result, our knowledge of the site-specific functions of O-GlcNAc modified proteins is very limited. Development of an O-GlcNAc specific antibody in 2001 by Hart and colleagues [3] has added some momentum in this field and contributed significantly in the identification of O-GlcNAc modified proteins. As O-GlcNAc modification in protein occurs at serine/threonine residues, the potential for interplay between serine/threonine phosphorylation and O-GlcNAc modification has been realized very early on [4]. Then it was indeed found to be the most common feature associated with O-GlcNAc modification and attributed to the further development in this area [5-7]. However, unlike phosphorylation which is regulated by hundreds of kinases and phosphatases, O-GlcNAc cycling has only two mediators: OGT and OGA [1]. This would imply that there must be fundamental differences in the way O-GlcNAc modification in proteins is regulated in relation to phosphorylation.Earlier evidence regarding the interplay between O-GlcNAc modification and serine/threonine phosphorylation has pointed towards an inverse relationship between these two modifications [4-6]. However, emerging evidence suggests that the relationship between O-GlcNAc modification and serine/threonine phosphorylation is more extensive than initially thought [7,8]. Recently we have reported that tyrosine phosphorylation interacts with O-GlcNAc modification, a phenomenon which was previously not known [9]. Subsequentl
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