成熟度、施肥量、留叶数与烟叶组织结构和比叶重的关系

对不同成熟度、施肥量、留叶数处理的烟叶组织结构、比叶重进行研究,结果表明:烟叶的厚度、栅栏组织和海绵组织厚度以完熟叶>初熟叶>过熟叶,并随施肥量增加而变厚。成熟度提高,上二棚叶比叶重下降;施肥量与腰叶比叶重负相关,与上二棚叶比叶重正相关。留叶数增多.上二棚叶厚度交薄,腰叶和上二棚叶比叶重均降低。     

改进的开关性能：快速IGBT带来新的挑战

降低动态功耗需要快速地开关功率半导体,但是,快速开关IGBT带来的新挑战,就是对关断电压峰值有特别强烈的影响。关断过程中uce-和ic测量分析说明了直流母线寄生电感和模块电感之间的相互作用。这使得在给定的应用中非常容易分析出的薄弱环节并在模拟中发现最大的潜力。     

The critical transmural pressure of the abirway

The critical transmural pressure (Ptm) is defined as the transmural pressure of the airway at the site where and when flow is limited during a forced expiration. According to the presented theory, the maximal expiratory flow (Vmax) can be calculated from the relation between Ptm and the corresponding cross-sectional area of the airway (A). By means of a pitot-static tube, Ptm-A curves were constructed for several locations in the elastic airway of a mechanical model. From these curves local Vmax was calculated at different values of Ptm and compared with actual flow, i.e. measured Vmax for the entire airway. In the downstream part of the airway, the actual flow equalled calculated Vmax at most Ptm values. The site of flow limitation, being the most upstream point where actual flow equals calculated local Vmax could therefore be located. Theory and experiments showed positive as well as negative Ptm not influenced by change in upstream or downstream resistance. Flow limitation could therefore be initiated at distending as well as compressing pressures across the wall of the airway. V was regarded as a function of Ptm and the elastic recoil pressure of the lung (Pel). Measured and calculated iso-Pel, Ptm-V curves agreed well with one major exception: when Ptm less than Ptm measured curves were distorted due to a concomitant downstrean compression of the collapsible airway.     

金属斜板极限载荷的统一解析解

用统一屈服准则(俞茂宏,1991)对斜板进行塑性极限分析,得到斜板的统一极限载荷解析式。从而得到一系列从单剪屈服准则(特雷斯卡,1864)到三剪屈服准则(米泽斯,1913)再到双剪屈服准则(俞茂宏,1961)的各种斜板的极限载荷,并得到矩形板和菱形板的极限均布载荷p随不同屈服准则的变化曲线,文献中已有的解均为统一解析解的特例。本文得到一系列有规则变化的新的解析解,可以适合于各种拉压强度相同的材料以及从方板、矩形板到不同角度的各种斜形板。它的工程应用可以得到显著的经济效益。     

晶须碳酸钙的开发

利用碳酸化合成方法开发了文石型碳酸钙晶须材料,并对氯化镁浓度的影响和反应过程进行了详细研究。实验表明,氯化镁的加入有利于石石相碳酸钙的形成,在浓度为０．４ｍｏｌ／Ｌ以上可以得到单一文石晶须;反应终点可以通过ＰＨ值的测定加以检测。     

MSAP构建融合接入网

通信技术的不断发展、客户需求的快速变化以及大量新业务的产生,对运营商现有的本地网技术和应用提出了新的挑战,特别是投资规模最大、应用最为复杂的本地网接入层目前正面临着四大挑战：如何适应数据业务发展的要求、如何适应业务综合接入与汇聚的要求、如何适应向客户提供差异化服务的要求及如何适应网络灵活扩展的要求。而传统的PDH、光纤收发器、协转等接入设备及组网方案存在的技术单一、网络适应能力不足、运维成本高、管理功能不完善的问题日渐突出,已无法适应新的变化。因此,本地网的建设和发展对接入层设备和解决方案提出了新的要求：     

家庭智能化系统

由新加坡鸿城宝德胜有限公司生产的家庭智能化系统由保安、通讯和管理控制3个系统组成.其中保安系统具有如下功能:①防盗检测,触发警笛、警灯并通过电话通知保安公司;②当电话线或电源发生故障时系统会及时发出警告;③火警检测;④遥控关注模式,当子女分居时,可通过遥控按钮,使老人得到及时的援助.