电容器引线焊接机冲压切边凸轮的三维精确造型

根据电容器引线焊接机冲压切边模具中的凸轮设计要求,利用Pro/ENGINEER软件找出凸轮随动件滚子中心的轨迹,通过可变截面扫描间接得到凸轮的三维精确模型。为类似零件的建模提供一种行之有效的方法,并为后续的仿真分析和制造加工提供一种依据。     

Robust sparse principal component analysis

The model for improving the robustness of sparse principal component analysis（PCA） is proposed in this paper. Instead of the l2-norm variance utilized in the conventional sparse PCA model,the proposed model maximizes the l1-norm variance,which is less sensitive to noise and outlier. To ensure sparsity,lp-norm（0 p 1） constraint,which is more general and effective than l1-norm,is considered. A simple yet efficient algorithm is developed against the proposed model. The complexity of the algorithm approximately linearly increases with both of the size and the dimensionality of the given data,which is comparable to or better than the current sparse PCA methods. The proposed algorithm is also proved to converge to a reasonable local optimum of the model. The efficiency and robustness of the algorithm is verified by a series of experiments on both synthetic and digit number image data.     

窄带滤光片光学极值法直接监控的光学设计

窄带滤光片是应用于光谱学、激光、天文物理学、通信等各个领域的光学组件,精确控制每一层膜厚是制备滤光片的困难所在.采用光学极值法直接监控工件,可以同时制备多件滤光片.设计了监控光路和信号获得电路,通过探测到的测试信号,监控薄膜膜厚,实现了直接监控.     

基于Kanai-Tajimi模型的地震作用荷载新型识别方法

目的研究一种识别地震作用荷载的方法,为地震作用荷载的识别与相应结构的动力特性、损伤的识别提供一种新的途径,进一步为结构的安全性、损伤进程和耐久性等研究提供理论参考.方法利用Kanai-Tajimi模型将单位强度白噪声过程模拟为未知的地震作用,并将其作用在结构上,然后根据数值模拟计算得到的结构体系响应作为观测量,采用Kalman滤波对未知荷载状态加以识别.结果最终可以利用结构的加速度响应反演得出地震作用的等效荷载,在人工添加5%观测噪声的条件下,最大误差率为7%左右,而在人工添加10%观测噪声的条件下,最大误差率为8%左右.结论通过算例的验证,说明笔者所采用的方法精度较高,获得了较好的识别效果.     

Bone Tissue Response to the Bone-like Tissue Coating on Titanium

The objective of this study was to investigate the effects of mineralized bone nodules, formed in vitro by bone marrow stromal cells(BMSCs), on the new bone formation in bone defect and on implant surface. The mineralized bone nodules were generated by culture of Lewis rats BMSCs on titanium disks in osteogenic induction medium. The gap-healing animal model was used to create the bone defect facing the disk. The titanium disks in the presence of B group or in the absence of NB group bone nodules were randomly placed into one of the rat distal femurs. This self-control design was used to compare the bone formation in defects and on titanium surface, by Micro-CT, fluorescence staining, histological and histomorphometric analysis. The new bone formation parameters in bone defect area of B group were significantly higher than those of NB group at 2 weeks, including bone volume fraction, trabecular thickness and bone area ratio. The bone nodules pre-stained with Alizarin red disappeared mostly at 2 weeks, while the red fluorescence reappeared in the newly formed bone away from the disk surface. For the bone-implant contact, B group showed lower values than NB group at 2 weeks, but no significant difference was found at 4 weeks. Our results indicate that the mineralized bone nodules can be resorbed in vivo and promote the early osteogenesis in the bone defects, and bone nodules may be applicable for new bone generation in bone defect or modification of tissue engineering scaffold.     

民族传统体育项目引入高校体育课的研究

在高校开展少数民族传统优秀体育项目教学,不仅能使少数民族传统体育走向规范化、科学化,较好地展现学生的运动能力,培养民族文化情感,激发民族热情,更重要的是还能提高学生的身心健康和综合素质,有利于对民族传统体育的继承、发展和广泛地传播。     

红色文化:马克思主义中国化的文化棱镜

马克思主义基本原理的理论自觉、中国传统文化的文化自觉、人民群众的实践自觉的三者和谐互动与有机统一,创造与发展了中国主流意识形态与文化的特殊形态,二者构成了马克思主义中国化历程中的两个主要面相,在此进程中,生成了两种主要形态,即中国化的马克思主义理论形态和以革命遗迹为"底板"的红色文化形态。作为一种特殊的文化形态,红色文化不仅是马克思主义中国化的文化自觉和文化再造的产物,也是继续推进马克思主义中国化的文化展望的对象。     

Weathering modification of acrylic emulsion by introducing UV absorbing groups

A new kind of UV-absorbing silicon-fluorinated acrylic emulsion was prepared by emulsion polymerization with 4-allyloxy-2-hydroxybenzophenone, 3-methacryloxypropyltrimethoxysilane (MPS) and hexafluorobutyl methacrylate (HFMA) as functional monomers. The emulsion and its coating were characterized by transmission electron microscope, Fourier transform infrared spectrum (FTIR), X-ray photoelectron spectroscopy, ultraviolet absorption spectrum,thermo-gravimetric analysis, water contact angle (CA), and artificial accelerated aging test. The results indicated that the emulsion with core-shell structure was synthesized and showed prominent absorption peaks at 320 and 350 nm. The water CA of the coating was increased from 70.2° to 86.7° because of the incorporated HFMAs and MPSs. Both of the initial and final decomposition temperatures of the coating were increased by more than 20°C compared with those of the unmodified coating. After 10 days of accelerated aging, the color difference (ΔE) and rate of loss of gloss (ΔG) were only 2.78% and 5.22%, while those of the unmodified coating were as high as 22.94% and 78.57%, respectively. Because of the UV absorbers were incorporated by chemical reaction, the new coating had a more durable and effective anti-ultraviolet performance compared with the coatings the UV absorbers were introduced by physical blending.     

基于嵌入式的电网自动调度信息分级采集系统设计

传统系统在电网调度信息采集的过程中,未对其进行分级,导致系统采集数据误差较大,准确度较低.为了提高电网自动调度信息分级采集能力,提出基于嵌入式的电网自动调度信息分级采集系统.构建电网自动调度信息的大数据挖掘模型,结合嵌入式调度方法,实现电网自动调度信息分级采集和优化检索.仿真结果表明,电网自动调度信息分集采集的准确度较高,自适应性较好,具有一定可行性,数据准确性满足系统设计需要,达到实用效果.     

TiCp/Al预制块在Mg中熔化过程研究

将TiCp／Al预制块以不同的工艺加入到Mg液中进行熔化试验。结果表明，未搅拌时TiCp／Al预制块在800℃的Mg液中保温60min后仍不熔化，采用合适的搅拌工艺可使TiCp／Al预制块熔化，并且使TiC粒子在熔体中均匀分布。TiCp／Al预制块在Mg液中的熔化过程机理为：基体Al通过熔化和对淹扩散进入到Mg液中，TiC粒子间的结合力需通过搅拌产生的剪切力才能破坏，并随Mg液流动进入到Mg液中，机械搅拌可使TiC粒子Mg液中均匀分布。