Method of adaptive PLL bandwidth adjustment without phase slipping

In a system based on the phase lock loop（PLL）, a trade-off must be made between the tracking precision and the dynamic performance if constant parameters are adopted. To overcome this drawback, a new method called no phase slipping adaptive bandwidth（NPS-AB） is proposed, which can adjust the loop bandwidth adaptively for different working conditions. As a result, both the tracking precision and the dynamic performance can be achieved concurrently. NPS-AB has two features to keep the loop stable： one is the capability of quick response to dynamics; the other is a series of additional constraints when the bandwidth is switched. Compared with other methods, there is no phase slipping during the adjustment process for NPS-AB. The phase integer ambiguity can be avoided and the phase value is kept valid. It is meaningful for carrier ranging systems. Simulation results show that NPS-AB can deal with sudden dynamics and keep the pseudo-range value stable in the entire dynamic process.     

State transfer control of quantum systems on the Bloch sphere

The state transfer under control fields is analyzed based on the Bloch sphere representation of a single qubit. In order to achieve the target from an arbitrary initial state to a target state, the conditions that parameters should satisfy are deduced separately in two different requirements: One is in the case of the rotation angle around the x-axis being fixed and another is in the situation with a given evolution time. Several typical states trajectories are demonstrated by numerical simulations on the Bloch sphere. The relations between parameters and the trajectories are analyzed.     

大型结构地震历时分析的Ritz缩减技术

把Ｒｉｔｚ向量直接迭加法与静力子结构法相结合．建立缩减结构动力方程直接积 分的近似算法．算例表明，这一方法对于诸如混凝土坝等大型结构地震反应的历时分 析是很有效的．     

一类三次Kolmogorov系统的定性分析

本文讨论了一类三次Kolmogorov系统(Ⅰ),在第一象限得到了可行平衡点的全局稳定性,正平衡点的全局稳定性以及围绕正平衡点极限环的存在性与唯一性。推广了[2]、[3]、[4]中的结论,并对所得结论给予了生物解释。     

CrNiMo钢缺口根部疲劳裂纹萌生的研究

本文采用单边缺口板状试样研究了四种含碳量的CrNiMo钢缺口根部的疲劳裂纹萌生寿命及其萌生机制。裂纹萌生可能有四种方式—沿驻留滑移带压入挤出、微孔聚集型切变、准解理和沿晶机制。文中论述了钢的含碳量、热处理规范及外加应力水平对裂纹形核机制的影响。研究表明:在双对数坐标中,表观循环应力范围和萌生寿命的关系可用两段不同斜率的直线来描述,两段萌生线的分界点随钢的强度水平提高而迅速向低周次范围推移,但两段的裂纹萌生均仍属于应力疲劳范畴。文中分析了微观塑性变形对缺口根部实际循环应力范围和应力循环比的影响,给出了对它们进行修正估算的方法。修正后的实际循环应力范围和萌生寿命的关系可用一条直线反映出来。在此基础上,提出了一种用光滑试样应力疲劳曲线估算缺口根部裂纹萌生寿命的新方法。     

高精度裂纹闭合测试仪的研制及应用

在材料的断裂与疲劳问题的研究中,裂纹尖端的闭合行为一直是人们十分关注的课题,它是深入研究材料断裂和疲劳机理的重要基础,然而精确地检测裂纹闭合行为的重要参数——裂纹张开载荷P_(op)仍是一个研究课题。高精度裂纹闭合测试仪的研制成功,则提供了有效的研究手段。本文重点介绍仪器的设计原理,电路的设计及其应用实例。     

碳还原锆英石分离SiO2和ZrO2

进行了配碳量，温度，时间和颗粒大小及试样形式对碳还原锆英石中ＳｉＯ２的实验研究，得到相应脱硅率的影响规律，理论上，脱硅率的极大值可达到９７．２２％，碳还原锆石的表现反应活化能，在１６００～２０００℃温度范围内为２８２．０４ｋｊ／ｍｏｌ。锆英石被碳还原的限制环节是锆英石的热分解，而不是它裂解成ＳｉＯ２之后再与碳的反应。     

十种（株）杜氏藻β－胡萝卜素的提取及含量比较

建立了从杜氏藻鲜藻中直接提取、纯化β－胡萝卜素及快速检测其含量的新方法，发现在十种（株）杜氏藻Ｄｕｎａｌｉｅｌｌａｂａｒｄａｕｉｌ中生成β－胡萝卜素的量最高，达藻干重的４．１９％，在最佳条件下可达１３％，经动物急性毒性实验测得小鼠对杜氏藻β－胡萝卜素的最大耐受量＞２４０ｍｇ·ｋｇ￣（－１）．     

A_r~+激光诱导氯气刻蚀硅

本文通过被局域刻蚀硅表面形貌的精确测量,考察了刻蚀速率对于激光功率、波长、反应室气压的依赖关系,讨论了在不同光斑尺寸和刻蚀深度下反应机理的变化,给出了衬底晶向和表面氧化层对刻蚀效果影响的一些新的结果。