双圆弧齿轮基于柔性轮缘的动态接触模型研究

基于柔性轮缘和ANSYS/LS-DYNA建立了双圆弧齿轮动态接触应力的分析方法和模型,分析了影响动态模型建立的因素。研究了动态模型中约束和载荷的处理方法及施加相当于扭矩的跟随载荷的具体方法,计算了实际运转过程中两种动态模型的齿面接触应力。计算分析表明,这种柔性体的齿轮接触模型能真实模拟齿轮啮合过程,为双圆弧齿轮动态性能研究奠定了理论基础。     

D290大孔阴离子交换树脂吸附钽的性能及动力学研究

研究了D290大孔阴离子交换树脂从草酸水溶液中吸附钽草酸配合物的性能和动力学。实验结果表明，在[（NH4）2C2O4]＝0．13mol／L、[K2S2O7]＝0．03mol／L、[Ta]＝8×10－5mol／L，pH＝1．0条件下，钽的吸附率有最大值。测得Freundlish常数K＝11．59，吸附速率常数k25℃＝1．5×10－4s－1，吸附活化能Ea＝46．64kJ／mol，钽的饱和吸附容量为每克干树脂170．4mg。载钽饱和柱可用6mol／L硫酸洗脱，洗脱率可达98．92％。     

耐酸耐氧双歧杆菌突变株的选育与冷冻浓缩发酵剂的制备

应用紫外线、60Co辐照育种,选育出1株耐酸、耐氧的长双歧杆菌突变株GKSW1101.该菌株在pH4.5的液体培养基中,37.5℃培养24h,活菌数达到4.2×108cfu/mL.采用加碱中和保持培养液pH6.0～6.进行发酵,在4℃、6000r/min离心15min收集菌体,添加脱脂奶粉、甘油、蔗糖,L-半胱氨酸盐酸盐为冷冻保护剂,-25℃冷冻保藏,制备成双歧杆菌冷冻浓缩发酵剂,活菌数达到2.4×1010.cfu/g,-25℃贮存3个月后,活菌存活率为50%.     

基于卷积神经网络的物流货物图像分类研究

基于卷积神经网络(CNN)针对物流环境下货物的图像分类问题进行了研究.首先,在实际物流环境下收集了13种货物的ROI图像,并通过每隔10°旋转的方式来扩充数据集以防止过拟合现象的发生;然后,在考虑了实际硬件条件的情况下构建了轻量级CNN,并进行了基于自建数据集的训练,训练实验发现,轻量级CNN模型具有很快的收敛速度并在验证集取得了100％的准确率;最后,研究了旋转对货物图像分类性能的影响,并进行了可视化分析,验证了CNN对旋转操作基本不具备一致性.     

燃机端面齿联轴器刚度特性参数化建模与实验

为研究刚度特性对重型燃机端面齿联轴器工作行为的影响,构建端面齿联轴器刚度分析参数化模型,对端面齿接触压力、扭转刚度、压缩变形等重要参数进行计算分析.采用有限元方法研究联轴器结构变形与刚度的变化规律.用实验装置对联轴器的变形和刚度进行了直接测试,刚度模型计算结果与有限元结果以及实验结果吻合较好.研究结果表明:螺栓预紧过程中端面齿及轮盘圆柱发生了不同程度的扭转,导致联轴器各部件刚度特性各有不同,其中端面齿压缩刚度随预紧力增大明显增大,而其它部件的刚度略微减小.由于扭转的存在,端面齿联轴器在变形、刚度变化规律、接触应力及接触状态等特征上有别于一般的联轴器.     

Numerical investigation of spinneret geometric effect on spinning dynamics of dry‐jet wet‐spinning of cellulose/[BMIM]Cl solution

In this study, the effect of spinneret geometry, including the entrance angle α of the entrance channel, the length L_s, and the diameter D₀ of the exit channel, on the spinning dynamics of dry‐jet wet‐spinning of cellulose/1‐butyl‐3‐methylimidazolium chloride ([BMIM]Cl) solution was simulated by using finite element method. Based on the mathematical model of dry‐jet wet‐spinning established in our previous work (Xia et al., Cellulose 2015, 22, 1963) the radial and axial profiles of velocity, pressure, and shear rate in the spinneret and the profiles of diameter, temperature, and tensile stress in the air‐gap region were obtained. From the simulated profiles, the effect of spinneret geometric parameters on the flow behavior and the pressure drop of polymer solution in the spinneret and the die‐swell ratio near the spinneret was discussed. The entrance angle α of the entrance channel mainly influences the flow behavior of polymer solution in the spinneret and the die‐swell effect near the spinneret. As the decrease of the entrance angle α of the entrance channel, the vortices in the spinneret could be removed and the die‐swell ratio decreases. The increase of the length L_s of the exit channel results in the increase of pressure drop in the spinneret and the decrease of the die‐swell ratio. It is also found that the increase of the diameter D₀ of the exit channel reduces the flow velocity of polymer solution and decreases the pressure drop in the spinneret at a constant mass flow rate. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43962.     

土遗址防风化加固材料的应用研究

表面加固是防止土遗址风化的一种重要手段,加固材料的选择关系到土遗址能否耐久保存。为了筛选出适合潮湿环境土遗址土体的防风化加固材料,本文采用TEOS、SD528、31J和BYG1003等4种常用防风化加固材料对取自潮湿环境土遗址的土样进行了加固实验。通过比较加固前后土样的重量变化、颜色变化、渗透深度、抗压强度和耐水性等指标评价各种材料的加固效果。结果表明,BYG1003是潮湿环境土体加固的合适材料,可以用作现场实验。     

2-(苯甲基)-7-氯茚并[1,2-e][1,3,4]噁二嗪-2,4a(3H,5H)-二羧酸4a甲酯的合成

以5-氯-1-茚酮为起始原料,经羰基化、不对称氧化、腙化和缩合反应合成了高效杀虫剂茚虫威的关键中间体2-(苯甲基)-7-氯茚并[1,2-e][1,3,4]噁二嗪-2,4a(3H,5H)-二羧酸4a甲酯。以5-氯-1-茚酮计,产品总收率达61.1%,产品结构经核磁共振分析验证。探讨了原料配比、溶剂的选择、氧化剂等因素对反应收率的影响。     

不同浸麦方式对麦芽酶活的影响

对大麦不同的浸麦方式即浸二断六、浸四断四、浸四断八和重浸法进行了研究,并将其对大麦麦芽质量的影响进行了比较.结果证明,采用浸四断八的浸麦工艺制作的成品麦芽具有较高的淀粉酶活力和蛋白酶活力.     

Study of thin cloud removal method for CBERS-02 image

The China Brazil Earth Resources Satellite (CBERS) ended the dependence on foreign satellites. Along with the series of CBERS and the enhancement of satellite applications, it is necessary to search correlative data processing methods. Because cloud appears in the atmosphere, an image with clear sky conditions is often hard to obtain. How to remove cloud is an important sector of increasing image quality. An improved homomorphism filtering method is adopted to remove thin cloud qualitatively at first, and all bands are selected to classify pixels. Based on the fact that visible band images contain more aerosol effects than infrared bands, visible bands are used to determine clear or hazy regions and the reflectances of different surface classes in clear regions are calculated. At last the mean reflectance of the same classes in clear and hazy regions is matched to remove cloud. The image visual effect is improved; meanwhile, the ground reflectance is retrieved to meet the needs of remote sensing quantification.