掘进机截齿表面合金熔覆强化研究

为强化掘进机截齿表面的力学性能,基于激光熔覆技术提出一种涂层制备工艺,并对表面合金的金相组织、显微硬度和元素相分布等特性进行了研究与分析。通过试验分析可知:涂层与母材之间的结合性良好,涂层晶粒细小,分布均匀;在三相化合物Mo2Ni3Si的作用下,涂层表面在不同磨损量下的显微硬度均保持稳定,且相比母材区提升了20%以上。     

Co40Ni33.5Al26.5合金马氏体相变、磁性与淬火温度的关系

Co-Ni-Al合金不仅可以作为铁磁性形状记忆合金,也是传统和高温形状记忆合金的候选材料,本文通过金相显微分析,DSC和VSM方法,研究了Co40Ni33.5Al26.5合金马氏体相变和Curie点随淬火温度变化的情况,结果发现该合金马氏体相变温度和Curie点与淬火温度成正比关系.马氏体相变的4种温度,即Ms、Mf、As和At基本平行变化,淬火温度每升高10℃,马氏体相变温度升高8～9℃,而Curie点升高6～7℃.其马氏体相变温度和Curie点随淬火温度的变化与基体相β的成分变化有关,β相中Al的含量随淬火温度升高而降低,因而马氏体相变温度和Curie点升高.并且发现随着淬火温度升高,Co40Ni33.5Al26.5合金马氏体相的磁晶各向异性有减弱的倾向.     

Silicon-29 solid-state nuclear magnetic resonance spectroscopy of composite interfaces

The types of structures and bonds that are formed with silicons in the composite interface were studied using ²⁹Si cross-polarization/magic angle sample spinning (CP/MAS) nuclear magnetic resonance spectroscopy (NMR). The change in mobility of silane coupling agent bonded to silica, as compared with bulk hydrolyzed silane coupling agent, can be monitored by the change in line width and the shift of resonances to higher fields, as well as by the change in the silicon-proton cross-polarization time T_SiH. In the silane coupling agent-matrix resin interface, the T_SiH values reflect the change in mobility as a function of the concentration and degree of hydrolysis of the silane coupling agent. It has been demonstrated that quantitative measurements of T_SiH can be used to investigate relative mobilities.     

海绵城市低影响开发措施综合效益评价体系及应用

为对低影响开发(LID)措施综合效益进行量化评价,综合考虑生态、经济及社会等因素,选取径流量削减率、污染物削减率、成本投资、运行效益、雨水利用、生态价值等16项LID措施评价指标,采用层次分析法和熵权法确定指标权重,基于云模型构建了 LID措施综合效益评价体系.将评价体系应用于南京一住宅小区的4个LID措施初步设计方案...     

鼓泡床生化反应器中壳聚糖的固定化Penicillium sp.ZD-Z1降解及性能表征

采用多孔聚氨酯泡沫对Penicillium sp．ZD-Z1菌进行了固．定化,在鼓泡床生化反应器中同时产酶降解壳聚糖,在30℃下pH5．0通气量为0．1m^3／h条件下,连续进行18批同时产酶降解试验,结果发弧壳聚糖酶活力和壳聚糖降解效率能保持稳定,每批产生的壳聚糖酶活力可达0．128U／mL（发酵液）以上,壳聚糖的粘均分子量可以降解到4ku以下,通过控制培养时间就可以得到重均分子量为120172、28425、16448、5599,峰尖分子量17579、111583、111235、3351的壳低聚糖。利用酶法降解所得的低分子量壳聚糖在经初步的分离纯化后,经红外光谱分析后,壳聚稽在酶解前后主要峰位置没有变化——壳聚糖的化学结构并未发生改变,这表明固定化Penicillium sp ZD-Z1菌产酶降解壳聚糖反应易于控制,不改变壳聚糖的化学结构,是一种有效的制备高品质壳低聚糖的方法。     

磁悬浮式针织提花驱动方式理论研究与探讨

摘要 基于磁悬浮理论,提出将电磁力直接作用在织针上的悬浮式驱动织针理论研究,探讨针织圆纬机的悬浮驱动选针控制原理的可行性研究;针对磁悬浮式驱动织针方式,提出了一种悬浮式织针基本结构,通过磁悬浮式织针装置磁路分析、织针摩擦热及热分析,获得了织针的热运动分析结果;文中还介绍了织针位置检测与控制模型的研究、以及采用陶瓷作为动织针的位移传感器的绝缘基底材料,传感器极片涂层方法等,为后续进一步研究磁悬浮式驱动织针理论,实现织针在狭小空间内织针提花驱动方式提供可靠的理论依据。     

降血脂鼠李糖乳杆菌的筛选及其对高脂模型地鼠血脂的影响

该实验旨在筛选出一株具有较强降血脂功能的乳杆菌。试验采用的菌株分离自健康婴儿肠道,通过邻苯二甲醛比色法测定菌株降胆固醇能力、单试剂法测定降甘油三酯能力,并测定了其对酸及胆盐的耐受性,从中筛选出具有降胆固醇和降甘油三酯功能较强的菌株进行16S rDNA鉴定。通过建立高血脂地鼠模型,研究菌株体内降血脂能力。结果表明,鼠李糖乳杆菌HCS01-013的降胆固醇和甘油三酯能力较强,其胆固醇降解率达到35.40%;甘油三酯降解率达到44.32%;在0.3%和1.5%的胆盐环境下培养17 h的存活率分别为99.67%和96.79%,在pH 3.0和pH 2.0环境下培养17 h后存活率能达到88.76%和71.34%;黄金地鼠喂养高脂饲料建立的高脂地鼠模型后,喂养鼠李糖乳杆菌HCS01-013各剂量组与喂养生理盐水的模型对照组相比甘油三酯含量均明显降低。鼠李糖乳杆菌HCS01-013具有一定的降血脂功能,且耐逆环境能力较强,为该菌株相关研究及产品研发提供理论依据。     

气态烃自热转化炉冷态实验研究与数值模拟

采用恒温式热线风速仪测自热转化炉内速度分布,用Realizable κ-ε湍流模型对流场进行模拟,其模拟结果和实验结果比较吻合.轴距小于21d0(喷嘴直径)时,轴线速度的衰减规律不受催化剂床层高度和气速的影响.转化炉内回流量随着轴距的增加,先增大后减小;随着催化剂床层高度的增高,回流比分布曲线变窄,回流量最大值为进口流量的6～7倍;轴距小于20d0,催化剂床层高度对回流比大小的影响不大.在实验条件范围内,改变气速,回流比的大小不变.     

Formation Processes of β-C2S by the Decomposition of Hydrothermally Prepared C-S-H with Ca(OH)2

A mixture of CaO and silicic acid prepared with a Ca/Si ratio of 2.0 was hydrothermally synthesized at 80° to 200°C, and the thermal decomposition behavior of the products (C-S-H with Ca(OH)₂) was analyzed using XRD, ²⁹Si MAS NMR, and the trimethylsililation method (TMS). It was found that the main silicate anion structure of C-S-H was a mixture of a dimer and a single-chain polymer (larger than Si₅O₁₆) and that polymerization advanced with an increase of the synthesizing temperature. On heating, the products decomposed to form β-C₂S. It was found that the decomposition was gradual and that the-higher the temperature of hydrothermal synthesis, the lower was the temperature of the decomposition into β-C₂S. Although the decomposition proceeded to form a monomer (β-C₂S) from the polymer and dimer, this dimer was resistant to heat and did not decompose unless heated to above 400°C.     

Color and Vanadium Valency in V-Doped ZrO2

The distribution and chemical states of vanadium in V-doped ZrO₂ were studied to clarify the origin of the color of vanadium-zirconium yellow pigment in comparison with vanadium-tin yellow pigment. ESCA data and measurements of lattice constants of V-doped ZrO₂ revealed that vanadium was dissolved mainly as V⁴⁺ substituting for Zr in ZrO₂ lattice, and its solubility limit was 0.5 wt% as V₂O₅. It was found that the yellow color of vanadium-zirconium yellow was produced predominantly by the dissolved vanadium and that the contribution of vanadium oxide on ZrO₂ grains to the yellow color was about 1/30 of that of the dissolved vanadium when compared on the basis of equimolar quantity of vanadium. Most of the undissolved vanadium oxide was in an amorphous or a poorly crystallized state.