栓焊混合连接狗骨式梁柱钢节点残余应力有限元分析

焊接作为结构连接的一种重要形式被广泛应用于钢结构中.焊接过程中由于温度梯度产生的焊接残余应力,给实际工程安全带来很大的威胁,所以研究钢结构在焊接过程中产生的残余应力是十分必要的.利用有限元数值模拟软件ANSYS建立狗骨式梁柱节点顶底角钢、焊缝、螺栓混合连接的三维有限元模型,模拟梁柱节点焊接的温度场,在热弹塑性理论基础上求解焊接残余应力.结果表明：构件在焊接过程中主要受拉,并且在不同位置的应力各不相同.由于狗骨式节点的存在,削弱了节点对梁部分的约束.在梁上翼缘螺栓上出现焊接残余应力的最大值,在腹板角钢与柱连接的中间螺栓处出现最小值.这与规范中的规定基本相符.     

Recovery of flavonoids from grape skins by enzyme-assisted extraction

Grape skin contains large amounts of different flavonoids so it can be used for their recovery. Optimization of enzyme-assisted extraction of flavonoids was conducted using oenological enzyme preparations with respect to enzyme dosage, temperature, extraction time, pH, and enzyme preparation. Optimal conditions were obtained using enzyme preparation Lallzyme EX-V, at the temperature of 45°C, time of 3 h, pH 2.0, and enzyme dosage of 10.52 mg/g. The new optimized extraction method is less expensive, simple, accurate, and selective for the recovery of simple flavonoids. It is based on an environmentally-friendly extraction solvent which may provide a valuable alternative to conventional methods.     

Immunologic Effects of Stereotactic Body Radiotherapy in Dogs with Spontaneous Tumors and the Impact of Intratumoral OX40/TLR Agonist Immunotherapy

Stereotactic body radiotherapy (SBRT) is known to induce important immunologic changes within the tumor microenvironment (TME). However, little is known regarding the early immune responses within the TME in the first few weeks following SBRT. Therefore, we used the canine spontaneous tumor model to investigate TME responses to SBRT, and how local injection of immune modulatory antibodies to OX40 and TLR 3/9 agonists might modify those responses. Pet dogs with spontaneous cancers (melanoma, carcinoma, sarcoma, n = 6 per group) were randomized to treatment with either SBRT or SBRT combined with local immunotherapy. Serial tumor biopsies and serum samples were analyzed for immunologic responses. SBRT alone resulted at two weeks after treatment in increased tumor densities of CD3+ T cells, FoxP3+ Tregs, and CD204+ macrophages, and increased expression of genes associated with immunosuppression. The addition of OX40/TLR3/9 immunotherapy to SBRT resulted in local depletion of Tregs and tumor macrophages and reduced Treg-associated gene expression (FoxP3), suppressed macrophage-associated gene expression (IL-8), and suppressed exhausted T cell-associated gene expression (CTLA4). Increased concentrations of IL-7, IL-15, and IL-18 were observed in serum of animals treated with SBRT and immunotherapy, compared to animals treated with SBRT. A paradoxical decrease in the density of effector CD3+ T cells was observed in tumor tissues that received combined SBRT and immunotherapy as compared to animals treated with SBRT only. In summary, these results obtained in a spontaneous large animal cancer model indicate that addition of OX40/TLR immunotherapy to SBRT modifies important immunological effects both locally and systemically.     

等离子体预处理对狗毛吸附铁离子性能的影响

采用低温等离子体对狗毛进行预处理,研究了等离子体预处理条件对狗毛吸附Fe3+性能的影响.结果表明:等离子体处理条件对狗毛Fe3+的吸附性能有很大影响,经适当条件等离子体预处理的狗毛对Fe3+的吸附能力及吸附速率显著提高,最大吸附量可达36.96 mg/g,比未处理狗毛的Fe3+吸附量提高了15.23 mg/g;而且脱吸附后的狗毛还可以重复利用.     

Science & Islam: A History

Nile perch (Lates niloticus) skin is a major substitute for whole fish especially among low-income groups who are especially vulnerable to protein and micronutrient deficiencies. The object of this study was to determine the extent of nutrient alterations that occur in Nile perch skins when subjected to various processing and cooking techniques. Whereas the study showed that Nile perch skins are rich sources of zinc, iron, calcium and lipids, their content is significantly altered by the various preparative methods currently in use.     

Preparative separation and purification of lycopene from tomato skins extracts by macroporous adsorption resins

In order to separate and purify lycopene from tomato skins extracts (lycopene oleoresin) with macroporous adsorption resins (MARs), the adsorption properties of twenty-four kinds of MARs were evaluated. The results showed that LX-68 had higher separation efficiency than other resins. Based on the static experiments with LX-68, it was found that the experimental data fitted best to the pseudo-second-order kinetics model and Langmuir isotherm model. The separation parameters of lycopene from tomato skins extracts were optimised through dynamic adsorption/desorption experiments with the column packed by LX-68. Through only one cycle treatment, the lycopene content in lycopene oleoresin increased 30.4-fold from 0.21% to 6.38%, with a recovery yield of 66.9%, which were determined by HPLC method. The results showed that MARs would provide useful help for the development of large-scale manufacture in the separation of lycopene from tomato skins extracts.     

基于AVR单片机的步进电机控制

对AVR单片机AT90S8515进行编程，实现对35BYJ46型四相八拍步进电机的控制，以达到精确定位的目的．使AT90S8515单片机并行口C口高四位PC7～PC4分别与驱动接口芯片ULN2803的输入引脚A、B、C、D相连，并使驱动芯片的4个输出引脚分别与步进电机的4、3、2、1四个励磁线圈的引脚相连．通过对单片机进行编程，使数据从C口高四位输出经驱动电路放大后控制步进电机，使其按照单片机编写的程序进行按步骤的正序旋转或逆序旋转．     

狗股骨近侧端动脉血液供应的初步观察

应用动脉灌注法，观察股骨近侧端动脉血液供应有关的动脉血管来源，分支及走向，观察结果表明，供应股骨近侧端的血管主要有5条，股深动脉，旋股内动脉，旋股外动脉，臀前动脉和臀后动脉，在以上动脉中旋股内动脉是最主要的供血动脉，股后动脉后部发出的升支与臀后动脉，股深动脉和旋股内动脉的肌支在股后肌群中存在大量吻合支，故可认为，股后动脉也与股骨近侧端血液供应有关。     

胎压报警系统的电池节能方案设计

首先介绍了胎压报警系统的总体监控流程和系统的应用前景，分析了胎压监控流程对于电池能耗的严重影响，监控流程设计不当将减少装置的使用寿命。最后提出了使用睡眠功能和看门狗定时唤醒的节能方案，并利用数据分析了系统程序优化之后的节能性。     

淡水鱼皮胶原蛋白提取工艺研究(Ⅰ)

研究了罗非鱼、鳙鱼、草鱼和鲫鱼4种淡水鱼皮胶原蛋白的提取工艺。结果表明,鱼皮用乙醚2次除脂效果显著,除脂率依次为92.4%、95.1%、66.8%和76.7%,除脂后胶原蛋白的提取率和得率都略有增加。除非胶原蛋白的工艺为:先用NaOH浸泡6h,再用NaCl浸泡6h,4种鱼皮胶原蛋白对应的提取率分别为34.4%、28.7%、31.5%和42.5%,得率依次为8.4%、8.0%、8.2%和6.1%,比其他处理相应高出0.4-2.3倍、0.04-1.6倍、0.1-0.9倍和0.07-0.5倍。乙酸的提取效果优于柠檬酸,对应提取率分别为34.8%、23.6%、33.6%、43.0%,得率依次为8.5%、6.6%、8.63%、6.19%,比柠檬酸相应高2.4-4.3倍、1.7-4.0倍。温度对罗非鱼、鳙鱼和草鱼鱼皮胶原蛋白提取影响较大,最佳提取温度都为20℃,其对应提取率依次为34.05%、27.05%、33.38%,得率分别为8.32%、7.54%、8.58%;温度对鲫鱼鱼皮胶原蛋白的提取影响较小,在520℃范围内提取率和得率分别约为42%和6%左右。