Design and analysis of a novel cascade control algorithm for braking-by-wire system based on electromagnetic direct-drive valves

In order to improve the response speed and control precision of the braking system with parameters uncertainty and nonlinear friction, a braking-by-wire system based on the electromagnetic direct-drive valve and a novel cascade control algorithm was proposed in this paper. An electromagnetic linear actuator directly drives the valve spool and rapidly adjusts the pressure of braking wheel cylinders. A dynamic model of electromagnetic direct-drive valve considering improved LuGre dynamic friction is established. A novel cascade control algorithm with an outside loop pressure fuzzy controller and an inside loop electromagnetic direct-drive valve position controller was proposed. An adaptive integral robust inside loop controller is designed by combining friction compensation adaptive control law, linear feedback, and integral robust control. The uncertainty parameters and the friction state are estimated online. The stability of the cascade controller is proved by the Lyapunov method. Then a multi-objective opitimizemization design method of control parameters is proposed, which combines a multi-objective game theory and a technique for order preference by similarity to ideal solution (TOPSIS) based on entropy weight. The results show that the pressurization time of cascade control is less than 0.09 s under the 15 MPa step target signal. The control precision is improved effectively by the cascade controller under the ARTEMIS condition.     

一类特殊半鞅驱动的随机微分方程解的存在唯一性

研究了随机微分方程dXt=F(X)tdZt解的存在唯一性,其中F为非Lipschitz系数,Z属于一类特殊半鞅.     

疏筋活血汤加减方治疗126例腰腿痛气滞血瘀证患者的临床疗效观察

目的:探讨疏筋活血汤加减方治疗腰腿痛气滞血瘀证的临床疗效研究。方法:腰腿痛气滞血瘀证患者126例,将其随机分为观察组68例和对照组58例。对照组口服双氯芬酸钠双释放肠溶胶囊,观察组内服中药疏筋活血汤加减方,并将药渣敷于患处。观察指标为临床疗效评价,VAS评分,M-JOA评分,ODI评分,IL-6和NO,血液流变学。结果:患者经治疗后观察指标具有显著变化,临床总有效率高于对照组;VAS评分、ODI评分明显降低,M-JOA评分升高IL-6、NO和血液流变学均下降,观察组变化幅度明显高于对照组,有统计学意义(P0.05)。结论:疏筋活血汤加减方治疗腰腿痛气滞血瘀证能有效缓解患者的临床症状,改善患者腰腿部功能,疗效满意。     

零被引论文产生的原因分析——以《植物营养与肥料学报》为例

摘 要 【目的】通过综合定量分析同行评审专家对零被引论文学术价值和学术质量的评审意见,阐明科技论文发生零被引的内在原因。【方法】利用CNKI学术文献总库提取了《植物营养与肥料学报》1994—2012年发表的零被引论文,统计分析了零被引论文与论文第一作者类型的关系,利用保存的2008—2012年期间的同行专家审稿意见,对零被引论文的学术价值和学术质量评价指标进行了归纳总结和定量分析。【结果】 不同类型作者对零被引论文贡献大小为研究生（47％）>副高（23％）>初中级（17％）>正高（13％）;44%的同行评审专家认为,零被引论文涉及的科学问题属于国内领先,但超过90%的专家认为零被引论文的试验设计、研究方法和结果分析存在严重缺陷。【结论】严重的稿件质量问题与零被引论文产生密切相关,减少科技期刊论文的零被引率,需要“作者-审稿专家-编辑协同控制”。     

基于三次成本函数和时空相依的城市土地供应经济性评价——以282 个地级及以上城市为例

城市土地供应的经济性不仅是土地一级供应的核心问题,也是至关重要的土地供需影响因素和土地市场要素,直接决定了土地市场调控的成效。基于三次多项式成本函数建立计量模型,并使用考虑了土地供给、需求和价格影响因素存在时间、空间相关性的实证计量方法和经济性评价指标,得出2003年-2008年我国282个地级及以上城市中90%存在土地供应规模过低而产生的不经济现象,而少数大型城市又存在明显的规模报酬递减,并且,协议供应的规模经济性程度相对高于“招挂拍”供应,二者都表现出了“先上升再下降”的非单调变化趋势,其最优规模区间分别处于95%～99%分位和中位～80%分位,同时,城市土地供应仍然存在较为明显的范围不经济现象。研究结果表明我国城市土地集约化供应具有极大潜力,应着力探索集约供应新机制。     

—种利用白光光谱仪测量绝对距离的方法研究

本文研究利用一种白光光谱仪测量绝对距离和位移的方法。利用迈克耳逊干涉结构,使用光谱仪S2000,进行光谱分析,在知道光学元件的群折射率和厚度的情况下,利用均衡波长的概念就可以得出绝对距离。该方法不需要应用相位重现程序,其测量范围大大超过传统白光干涉技术的测量范围,为绝对距离的测量提供一些详尽的参考。     

Development of a rapid and inexpensive plasma glucose estimation by two-point kinetic method based on glucose oxidase-peroxidase enzymes

A rapid and inexpensive plasma glucose estimation by two-point kinetic method based on glucose oxidase and peroxidase enzymes has been developed it takes only 11/2 minutes of time and validity of the method has been discussed.     

技能衰退与人员流动对于组织遗忘的影响研究——一个数学框架

对于组织遗忘的研究旨在找到导致组织经验流失的潜在因素.确定了两项对于组织遗忘产生影响的主要因素,即技能衰退与人员流动,并构建了相关的数学框架,用以研究这两项因素对于组织遗忘发生作用的区别及其之间的联系,以实现企业资源的有效配置.     

Increased density and coverage uniformity of viruses on a sensor surface by using U-type, T-type, and W-type microfluidic devices

Microorganisms, molecules, or viruses in the fluidic environment are usually at considerably low Reynolds numbers because of small diameters. The viscous forces of molecules and viruses dominate at considerably low Reynolds numbers. This study developed three microfluidic devices, that is, T type, U type, and W type devices, to control the flow movement, which can increase the adhesion density of viruses on the surface of the sensor. The linker 11-mercaptoundecanoic acid (11-MUA) and Turnip yellow mosaic virus (TYMV) were used in this study and measured by a confocal microscope. Fluorescent intensity and coverage of 11-MUA and TYMV were used to identify the adhesion density quantitatively. Results indicate that 11-MUA layers and TYMV disperse randomly by the dipping method. Attachment tests for T-, U-, and W-type devices demonstrated average fluorescence intensities of 1.56, 2.18, and 2.67, respectively, and average fluorescence coverage of 1.31, 1.87, and 2.55 times those of dipping techniques, respectively. The T-type device produced the lowest fluorescence coverage uniformity (10%-80%), whereas the W-type device produced the highest fluorescence coverage uniformity (80%-90%). Fluorescence intensity correlates positively with flow within a specified flow range; however, the exact relationship between fluorescence intensity and flow requires further study. Attachment tests for TYMV virus samples indicated that the W-type device produced an average fluorescence intensity of 3.59 and average fluorescence coverage of 19.13 times greater than those achieved through dipping techniques. Traditional immersion methods achieved fluorescence coverage of 0%-10%, whereas that of the W-type device reached 70%-90%.     

高校科研机构面临的困境和多层次结构科研机构体系的构建

近十年来，我国高校科研机构的数量和规模增长迅速。随着经济体制改革的深入和科技的日新月异，高校科研机构的问题和弊端也日益突现。为适应这些变化，在高校内建立多层次的科研机构和对不同类型的科研机构实施不同的管理模式是一种值得尝试的方式。     

提高教师科技创新能力 构建职业教育立交桥

在完善职业教育体系、构建职业教育立交桥的改革进程中,各级教育行政管理部门及各高等职业院校受制于高职院校的总体实力、师资水平、课程设置、经费来源等因素而举步维艰。要大力提高教师科技创新能力,以迎接构建职业教育立交桥进程中的机遇与挑战。     

光学显微镜和扫描电镜下的星肋小环藻(新种)的研究

A new diatom species, Cyclotella asterocostata is described in the paper. The species was collected from Miyan Reservoir in Beijing, Tangshan in Hebei, Shanyang in Liaoning, Suzhou in Jiangsu, Guilin in Guangxi.  It is characterized by a wide marginal region, with the width of the marginal region about half of the valve radius.  There are radiate rows of costa alternate with alveola on the surface of valve central region and marginal one.  The species has not an isolated punctum, but has some scattered puncta, on the surface of valve central region.