一种数字化矿井透地通信系统实现方案

针对矿井通信困难,提出了一种采用扩频技术、可数字化实现的矿井透地通信系统方案,并对该方案进行了理论分析和总体仿真,仿真结果及误码率分析表明了该系统设计方案的可行性,为系统的设计实现奠定了基础。     

SPKI2.0信任模型的改进及应用

本文简要介绍了SPKI证书,同时提出使用SPKI证书进行访问控制时容易出现的问题,即查找证书链失败的问题,并提出了对SPKI授权认证模型改进的方法,使得当授权证书链不存在时客户端建立新的证书链访问资源服务器,并将此模型应用于网上电子商务中。     

Effects of Lanthanum on Bone Resorbing Activity of Rabbit Mature Osteoclasts Co-Cultured with Osteoblasts

The effects of lanthanum (Ⅲ) on the bone resorbing activity of rabbit mature osteoclasts (OCs) in the presence of osteoblasts (OBs) were studied in vitro by measuring the number and area of absorption pits. La(Ⅲ) at concentrations ranging from 1.00×10-5 to 1.00×10-8 mol·L-1 show no effect on mature OC number (P＞0.05). In the OC-OB co-culture systems without La(Ⅲ), osteoblasts alone did not influence the pit number and area whether the two kinds of cells were in contact or not (P＞0.05). Under the OC-OB not-in-contact condition, the effect of La(Ⅲ) on the bone-resorbing activity of OCs was similar to that of La(Ⅲ) in the absence of OBs (P＞0.05). However, while OCs were in direct contact with OBs, the inhibitory effects of La(Ⅲ) on OCs' bone-resorbing activity decreased at the concentrations of 1.00×10-5, 1.00×10-6 and 1.00×10-7 mol·L-1, and the promotion effects increased at 1.00×10-8 mol·L-1 (P＜0.05). The results suggest that direct cell-cell contact between OC and OB be essential for OBs to play their role in regulating the response of OCs to La(Ⅲ).     

电价及电费计算

电费计算工作政策性很强 ,本文依据现行电价制度及有关电费电价的政策法规精神 ,对不同的客户在不同用电方式下的电费计算问题 ,进行了归类总结。     

圆锥相贯线的数控切割原理

对圆锥面上的两种相贯线进行了分析，获得了数控切割加工的理论模型，并介绍了为解决这类空间曲线切割加工而研制的数控切割设备，以及该设备在宝山钢铁公司３号高炉制造中的成功使用     

利用模型驱动体系架构开发分布仿真系统

作为现有分布交互仿真的标准，尽管HLA的原理非常优秀，但由于其实现上存在的一些问题，致使HLA的应用仅仅局限于军队的某些仿真领域。HLA所倡导的可重用性也受限于特定的仿真支撑平台，如果仿真平台改变，则现在基于HLA开发的仿真组件的可重用性将无法得到很好的体现。模型驱动体系架构(MDA)是对象管理组织(OMG)提出的一种先进的软件开发模式，其核心思想是将系统的行为逻辑模型与特定的目标平台分离，此模型仅需建立一次，然后可以重用于现有的或将来可能推出的不同的软件平台。将MDA技术应用到HLA将会带来诸多的好处。该文简要介绍了MDA的概念，阐述了MDA将会给仿真领域带来的巨大影响，最后给出了利用MDA开发分布仿真系统的一般步骤。     

小企业并非一筹莫展

小型企业的群体力量在所有国家中都是不容忽视的,不过,虽然越来越多的小企业感受到了电子商务的巨大吸引力,但普遍的应用却尚未展开     

集 CAD/CAM/CNC 于一体的板材下料系统

为了实现板材下料的自动化，我们研制了一套集ＣＡＤ／ＣＡＭ／ＣＮＣ于一体的板材下料系统。本文介绍了该系统的硬件组成，软件设计及其应用     

Microstructure and mechanical properties of poly (vinyl chloride) modified by silica fume / acrylic core-shell impact modifier blends

This research explored replacing acrylic core-shell impact modifier (AIM) by silica fume to toughen PVC. 100%, 75%, 50% and 25% of AIM (8 phr) were substituted by silica fume in PVC respectively, and then processed by dry blending and twin-screw extrusion. Severe silica fume agglomeration was observed by scanning electron microscope (SEM) in the PVC matrix when 8 phr pure silica fume was used and processed by screw speed of 20 rpm. Its tensile strength was thereby reduced by 38% comparing to unmodified PVC. The silica fume was successfully dispersed while the screw speed was slowed down to 10 rpm to give a stronger screw torque and a longer melt residential time in the extruder. The tensile strength was ’recovered’ to a level comparable to unmodified PVC. Impact test were performed on all formulations extruded at 10 rpm screw speed and synergetic toughening effect was found with 50% substitution and it had the impact strength that was comparable to 8 phr pure AIM toughened PVC.     

稀土相关专利分析

稀土金属作为我国重要的战略资源和优势资源之一,其战略意义不言而喻。本文利用汤姆森数据分析器,分析了近年来稀土相关专利,涉及年度申请趋势、重要国家/地区专利申请态势、领先机构研发重点以及专利技术布局等方面信息。