采用模型设计医用固态硅橡胶充填矫治额鼻部凹陷畸形

为探索可靠有效的矫治鼻部凹陷畸形的方法 ,用模型设计医用固态硅橡胶充填矫治额鼻部凹陷 .结果额鼻部凹陷完全消失 ,外形良好 ,患者无任何自觉症状 .模型设计可缩短手术时间 ,减轻患者痛苦 .     

空腔物体保温节能效果研究

通过理论分析，提出利用空腔物体内壁的辐射反射作用来提高聚胺脂泡沫绝热材料的保温绝热效果，并对空腔内贴有铝箔的聚胺脂与单纯聚胺脂进行对比实验，证实了聚胺脂内空腔能有效地提高其绝热保温效果，达到节能目的。     

拖拉机变速箱空心花键轴的优化设计

本文用随机方向法对拖拉机变速箱空心花键轴进行优化设计,为拖拉机变连箱抽的设计计算提供参考。     

Statistical properties of large published classifications

Large published classifications typically consist of sets (called taxa) hierarchically arranged according to taxonomic rank. A statistical survey of 23 such classification reveals the following distinctive properties. The pattern of mandatory and optional taxonomic ranks is similar to a Guttman scale. Mean taxon size (defined as the number of next-lower-rank taxa per higher-rank taxon) is a U-shaped function of mandatory rank, and averages about seven across ranks with no significant differences between classifications. The variability of taxon size is a decreasing function of mandatory rank. The generality of these properties across classifications suggests that they are determined by the psychology of the classification process. In contrast, there are significant differences between classifications in the variability of taxon size and in the prevalence of optional ranks, both of which are greater in biological than in nonbiological classifications. These differences may reflect the nature of the materials classified. This research was supported by a research grant from the UCLA Academic Senate and by computer time from the UCLA Office of Academic Computing.     

高速钢表面涂层的工艺与性能

运用空心阴极离子镀设备在高速钢表面以不同的工艺沉积了(Ti,Al)N涂层,并对该涂层的硬度、结合力、耐磨性、抗氧化性以及切削寿命进行了试验,获得了本试验条件下最佳工艺参数。     

不同应力路径下砂岩的宏细观力学响应特性

为了研究应力路径对砂岩的宏观、细观力学响应的影响,基于颗粒离散元方法构建了空心圆柱试样并开展了6组不同应力路径的试验,分别研究了砂岩试样在不同应力路径下的宏观应力-应变响应,以及细观法向与切向接触力的分布规律。研究结果表明：当试样内围压相同时,随着外围压的增加,试样破坏时的体积应变也随之增加,即试样的膨胀现象愈加明显;当试样的外围压相同时,随着试样内围压的增加,试样破坏时的体积应变随之先增长后减小。在中主应力系数不为0时,中主应力系数越大,试样的径向应变与环向应变之和的绝对值越大。在内围压相等的情况下,随着外围压的增加,试样的法向接触力增加。当外围压相等,内围压增大时,试样的法向接触力减小。     

Highly sensitive ZnO nanoparticles-loaded In2O3 hollow microsphere for detecting ppb-level NO2 at low working temperature

This paper presents a NO₂ sensor operating at low temperature, which was fabricated by ZnO nanoparticles-loaded In₂O₃ hollow microspheres composites. SEM, XRD, XPS and HRTEM were executed to determine the morphology and microstructure of ZnO–In₂O₃. The sensing performance of pure In₂O₃ and ZnO–In₂O₃ composite sensors was tested. The NO₂ sensing properties of the composite were greatly improved in contrast with the pure In₂O₃ sensor at the optimized operating temperature (75 °C). ZnO–In₂O₃ composite sensor exhibited an obviously higher response (805.2 for 100 ppb NO₂) than that of the pure In₂O₃ sensor (14 for 100 ppb NO₂). In particular, the response/recovery rate of ZnO–In₂O₃ composite sensor was greatly improved in contrast with the pure In₂O₃ sensor. The n-n heterojunctions created at ZnO–In₂O₃ interfaces improved the sensing performance.     

Combustion forming hollow nanospheres as a ceramic fortress for flame-retardant fiber

Simple, effective and safe flame retardants are required to improve flame retardant properties of polymer fibers.However, traditional additive flame retardants, such as halogen-flame retardants and intumescent flame retardants, are likely to cause phase separation of functional phases due to their poor dispersibility and compatibility, or are difficult to be suitable for the high temperature processing conditions of melt-spun fibers. Here, in an effort to develop a practical flame retardant system in which zinc diphosphinate(DEPZn) and D-glucose(DG)were selectively incorporated into polyethylene terephthalate(PET) fiber was developed. As a result, the dense nano-scale zinc phosphate microspheres were formed on the surface and inside the residual carbon during combustion. Thus, PET fibers were endowed with excellent flame retardancy through a thermal barrier and enhancement of physical strength for the carbon layer. Moreover, a synergistic flame-retardant effect was found between DEPZn and DG. DG reduced the size of the zinc phosphate nanosphere from 200 nm to 50 nm, making the carbon layer denser and smoother. As a result, the peak heat release of the resultant PET composite fiber decreased to 410 k W/m~2 compared 1276 k W/m~2 for neat PET fiber. Moreover, the total smoke release also dropped from 71 MJ/kg of neat PET fiber to 64 MJ/kg for PET composite fibers. These results provide a promising strategy for the production of industrialized PET flame retardant fibers.     

基于ObjectARX建筑构件中圆管相贯算法研究与实现

在建筑过程中需要对空心圆管、空心矩形管等构件进行处理,当构件的数量很庞大时,如果在AutoCAD中一个一个地处理将会耗费极大的人力和时间,因此有必要根据构件结构的特点研究相关的算法。根据实例研究和实现了使用ObjectARX在AutoCAD中可以快速有效地对构件进行处理的算法。     

一种新型空心钻头的设计

针对常规孔加工方法的缺陷，设计了一种新型空心钻头，给出了结构及其主要参考参数，为刀具（主要是钻头）的结构型式设计提供了一种新的思路。