PLC在氧化锌晶须加工中的应用

针对氧化锌晶须加工的工艺要求,结合生产实际设计了一套以西门子S7-300 PLC为控制器、带死区的增量式PID为控制算法的自动控制系统,实现了氧化锌晶须加工的自动监控与管理。实际生产的四针状晶须针长较长,针与针之间的空间角度接近理论值,产品质量为上等。     

比例阀和伺服阀在圆盘浇铸系统中的应用

随着工业自动化技术的不断发展,对设备控制的位置、速度以及精度要求越来越高,电液比例阀和电液伺服阀很好地达到了对工业控制的要求,在冶化工程公司研制的圆盘浇铸机以及电解机组中,都应用到了电液比例阀和电液伺服阀,从这些项目中的应用情况来分析电液比例阀以及电液伺服阀的原理性能以及在PLC控制系统中的具体应用。     

智能混合型控制器在温度控制的研究与应用

炉温控制系统具有温度时滞、非线性等特点，结合传统PID控制和模糊控制的优缺点，设计出一种混合控制器，解决炉温控制温度稳定性问题。当温度偏差值大于切换值时，模糊控制器做主控制器，以加快系统的温度响应特性。当温度偏差值小于切换值时，PID控制器做主控制器，以提高温度的控制精度。该控制器应用在焦炭反应性强度测定装置中，提高了控制温度的响应特性和精度，具有较强的鲁棒性，控制效果较好。     

料流阀控制系统性能分析

介绍电液比例方向阀用于梅山３号高炉料流调节阀的控制，通过对比例阀控制电流的控制，油缸速度及行程，料流阀开度的关系分析及与普通阀，伺服阀的比较，证明了使用电液比例阀控制料流阀的精确性和可靠性。     

基于模糊PID控制的摩擦负载系统的研究

提出一种采用电液伺服阀控制的液压摩擦负载系统,此系统利用液压缸作为执行机构时制动盘提供摩擦转矩.为了达到理想的控制效果,设计了模糊PID控制器,通过对电液伺服阀进行调节,来控制液压缸的跟随性能.在两种不同的控制算法下,对QDJ2815起动机进行恒转矩控制试验,得到相应的控制响应曲线,并分析了该闭环控制系统的实现情况,结果表明：模糊PID控制算法比常规PID控制算法具有更小的超调量,整个系统运行稳定可靠.     

模糊自适应PID电液位置伺服系统研究

基于电液位置伺服系统平台,引入模糊自适应PID控制器,建立了系统数学模型.利用Matlab/Simulink将其和常规PID控制器进行了仿真、比较分析.最后通过西门子PLC S7-300进行了试验验证.证明模糊自适应PID控制器具有响应快、超调小、稳定快、震荡小等优点.     

重载管片旋转液压系统的近似内模控制

针对盾构重载管片拼装旋转运动控制系统的强非线性和工作点的变化,设计了系统模型近似逆的内模控制器。该系统逆控制器能够体现出系统工作点的变化,其影响在控制系统中可以得到补偿,反馈量由原来的输出量反馈成为扰动量,容易设计控制器。对管片拼装旋转运动的控制仿真研究表明,与传统PID控制器相比,系统的近似内模控制器具有更好的动态控制性能,对工作点的变化具有更强的鲁棒性。     

基于复合干扰观测器的轧机液压伺服位置系统终端滑模控制

针对轧机液压伺服位置系统,考虑参数不确定性、负载扰动和输入饱和非线性的影响,提出一种基于复合干扰观测器的终端滑模控制方法。将轧机液压伺服位置系统中的参数不确定性、负载扰动以及输入饱和非线性视为复合干扰,通过选用快速终端滑模干扰观测器对其进行逼近估计,并将输出的估计值引入到所设计的控制器中进行补偿。通过稳定性理论分析表明,在所设计的控制器的作用下,闭环系统全局渐趋稳定。最后,基于某650 mm可逆冷带轧机液压伺服位置系统的实际参数进行仿真研究,结果表明,所设计的控制器能够实现系统输出对期望位置的准确跟踪。     

集总干扰下六旋翼飞行器的轨迹跟踪控制

针对复杂集总干扰下六旋翼飞行器轨迹跟踪控制问题,给出了混合积分反步法控制与线性自抗扰控制的控制算法. 首先,通过牛顿-欧拉方程建立六旋翼飞行器的非线性动力学模型,并剖析系统输入输出的数学关系. 其次,根据六旋翼飞行器动力学模型的特点,将其分为位置与姿态两个控制环. 位置环采用积分反步法控制理论设计控制器,通过引入积分项来提高系统的抗干扰能力,消除轨迹跟踪的静态误差;姿态环采用线性自抗扰控制技术设计控制器,通过线性扩张观测器估计和补偿集总干扰影响,提高系统的鲁棒性. 最后,通过2组仿真算例和1组飞行试验验证了本文所提飞行控制算法的有效性. 研究结果表明:该控制算法对集总干扰有较好的抑制作用,能够使六旋翼飞行器既快又稳地跟踪上参考轨迹,具有一定的工程应用价值.      

基于遗传PID的动静液复合转向优化控制研究

由于履带车辆常运行于恶劣的环境中,采用动静液复合转向机构的某型履带车辆在转向过程中,静液系统压力存在较大的波动,严重影响了车辆的转向等性能.为了使履带车辆动、静液系统配合平稳,采用电液比例阀替代实车上采用的充油阀,并在Matlab仿真平台下建立了动静液复合转向的系统模型,对转向过程的静液系统压力变化等情况进行了仿真.为了改善系统的综合性能,设计了遗传PID控制器,控制器可根据静液系统压力渡动状况实时控制进入液力耦合器的油量.仿真结果表明,改进后的系统工作过程平稳,动态响应迅速,能够很好地抑制了转向过程中静液系统压力的波动,提高了车辆转向的综合性能.     

Voices of fear and anxiety and sadness and depression: The effects of speech rate and loudness on fear and anxiety and sadness and depression.

Two studies investigated the role of expressive vocal behavior (specifically, speech rate and loudness) in fear and anxiety and in sadness and depression. In the 1st study, participants spoke about personally experienced fear and anxiety-arousing and neutral events using 3 different voice styles: fast and loud, normal, and slow and soft. In the 2nd study, participants spoke about personally experienced sad or depressing and neutral events using the same 3 voice styles. In both studies, the participants' highest levels of subjective affective and cardiovascular (CV) arousal occurred when they spoke about the emotional events in a mood-congruent voice style: fast and loud in the case of fear and anxiety, and slow and soft in the case of sadness or depression. Mood-incongruent voice styles canceled the heightened levels of CV arousal normally associated with these negative emotions. The voice-style manipulation had no significant effect on the participants' levels of CV arousal during the neutral discussions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Synthesis and analysis of mixed chlorinated-fluorinated dibenzo-p-dioxins and dibenzofurans and assessment of formation and occurrence of the fluorinated and chlorinated-fluorinated dibenzo-p-dioxins and dibenzofurans

Despite the use of multimodal therapy, higher-grade glioma is still uniformly fatal in the adult population. There is a considerable difference between the length of survival in each given patient, even within the same tumor type and malignancy grade group, suggesting that there are factors that might differentially influence outcome. To identify such factors, 107 patients with anaplastic or malignant glioma were retrospectively investigated. Clinical parameters and paraclinical data on the p53, mdm2, and EGFR genes at the DNA or protein level were evaluated by univariate analysis and Cox proportional hazards regression modeling. Kaplan-Meier survival estimation demonstrated that immunohistochemical positivity for mdm2 protein in patients with anaplastic astrocytoma or with glioblastoma multiforme was associated with a shorter survival time (p = 0.02). P53 gene mutations and immunopositivity for the epidermal growth factor receptor (EGFR) protein were not significantly related to poor prognosis. The Cox proportional hazards model revealed immunohistochemical positivity for p53, mdm2, or for both of them, the presence of postoperative irradiation, and the extent of surgical resection of tumor to be variables significantly associated with prolonged survival. EGFR overexpression, age over 60 years, and Karnofsky performance score below 40 points did not significantly shorten survival time. In conclusion, the present study identified immunohistochemically detected mdm2-protein overexpression as a statistically significant negative prognostic parameter in patients bearing anaplastic or malignant glioma. Association analysis of variables revealed a possible correlation between mdm2 and p53, which is also consistent with the biological interaction mode of both proteins in vivo.     

Sexuality and aging--usual and successful

BACKGROUND: As aging research increasingly reflects an effort to dissociate true time-driven changes from those that can be improved, sexuality in later life remains largely unexplored. Several problems are evident. There is a lack of normative data, a lack of a conceptual framework relating to the biology, psychology, and sociology of sex, and an attitudinal resistance that obscures the entire topic. METHODS: We conducted a three-part instructional series on major topics involved with sexuality and aging. We surveyed our group of attendees (n 158, average age 68 for males, 65 for females) before and after the series. RESULTS: A remarkably robust sex life was evidenced by both the men and the women, even until advanced old age. Yet, a substantially decreased involvement was reported from 10 years earlier. Despite current activities, people of both sexes wished they were participating even more than they currently were. Impotency was identified as the major negative feature for the men; relationship problems were for the women. A questionnaire 6 months after the series reported improved sexual attitudes, but no change in sexual activities from the earlier survey. CONCLUSION: Sexuality is a major quality-of-life issue which persists into old age. Our study showed that the usual sexual practices reported by our group were not considered by them to be ideal. The intervention of this instructional series provided improved sexual attitudes but not performance. Additional studies are encouraged.     

Spondylolysis and spondylolisthesis and sports

Spondylolysis and spondylolisthesis occur predominantly in the lower lumbar spine. Besides congenital defects such as predisposition of spondylolysis the correlation between competitive sports activities and an increased incidence of spondylolysis is proved. In early stages, complete healing can be achieved by conservative treatment (abstinence from sports activities for 3 months, orthesis). Persistence of pain, neurologic symptoms and progression of vertebral slipping are indications for operative treatment (reconstruction of the isthmus, dorso-ventral spondylodesis). The exercise tolerance depends on the extent of instability, progression of vertebral slipping and clinical symptoms. The limits of exercise tolerance vary among the individual athletes and require the decision of the physician. Backstroke swimming, abdominal and back muscle strengthening exercises, and types of sport involving smooth movements are advisable. Sports education in school is possible without restriction in patients with stable spondylolysis and in those with spondylolisthesis without unfavourable concomitant factors.     

Larks and owls and health, wealth, and wisdom

OBJECTIVE: To test the validity of Benjamin Franklin's maxim "early to bed and early to rise makes a man healthy, wealthy, and wise." DESIGN: Cross sectional analysis of sleeping patterns in a nationally representative group of elderly people, and longitudinal investigation of mortality. SETTING: Eight areas in Britain (five in England, two in Scotland, and one in Wales). SUBJECTS: 1229 men and women aged 65 and over who in 1973-4 had taken part in a survey funded by the Department of Health and Social Security and for whom data on sleeping patterns, health, socioeconomic circumstances, and cognitive function had been recorded. MAIN OUTCOME MEASURES: Self reported income, access to a car, standard of accommodation, performance on a test of cognitive function, state of health and mortality during 23 years of follow up. RESULTS: 356 people (29%) were defined as larks (to bed before 11 pm and up before 8 am) and 318 (26%) were defined as owls (to bed at or after 11 pm and up at or after 8 am). There was no indication that larks were richer than those with other sleeping patterns. On the contrary, owls had the largest mean income and were more likely to have access to a car. There was also no evidence that larks were superior to those with other sleeping patterns with regard to their cognitive performance or their state of health. Both larks and owls had a slightly reduced risk of death compared with the rest of the study sample, but this was accounted for by the fact that they spent less time in bed at night. In the study sample as a whole, longer periods of time in bed were associated with increased mortality. After adjustment for age, sex, the presence of illness, and other risk factors, people who spent 12 or more hours in bed had a relative risk of death of 1.7 (1.2 to 2.5) compared with those who were in bed for 9 hours. The lowest risk occurred in people who spent 8 hours in bed (adjusted relative risk 0.8; 0.7 to 1.0). CONCLUSION: These findings do not support Franklin's claim. A "late to bed and late to rise" lifestyle does not seem to lead to socioeconomic, cognitive, or health disadvantage, but a longer time spent in bed may be associated with increased mortality.     

Craniometaphyseal and craniodiaphyseal dysplasia, head and neck manifestations and management

Mechanical allodynia (MA) following hand injury is a well-documented clinical problem. The purpose of this pilot study was to examine the relationship between hand MA and the upper limb tension test (ULTT). The ULTT mechanically stresses the neural structures from the C5/6/7 neural foramina to the median nerve distally. This study examined 29 subjects with unilateral hand MA before and after a 2-week neural self-mobilization programme. There was a significant difference between the subjects' affected and unaffected sides when tested using the ULTT, both in reproduction of symptoms and in reduced range of motion of the ULTT. Following the self-mobilization program, there was an improvement in the range of the ULTT, and subjects reported a reduction in their symptoms. Complete recovery was not obtained in all cases. The results of this study suggest that the ULTT is a useful tool both in assessment and treatment of subjects with hand MA.     

深云立交桥梁检测及加固改造

根据深云立交桥梁的检测结果，对该桥目前的整体状况、工作状态，及其使用情况做出综合评价，对桥的病害原因进行了分析，并提出合理的加固方案。     

关于摩尔浓度及其与硬度转换关系问题的讨论

众所周知，国际单位制物质的量采用摩尔(mol)表示，近几年出版的给排水专业书籍，为了与国际单位制接轨，逐渐将摩尔的使用频率不断提高，被给排水技术人员广泛应用的新版给排水设计手册，将表示物质浓度的单位“当量／升”或“毫克当量／升”．改为mol／l或mmol／l，虽然编者对其基本单元定义作了说明，但在实际运用上仍会出现误解，     

《儿子与情人》的语码转换与男女二元对立

劳伦斯小说《儿子与情人》一个鲜明的语言特色就是标准英语和当地方言频繁的语码转换。莫瑞尔用方言来对抗妻子,而妻子坚持用标准英语,偶尔也用方言来讽刺、挖苦丈夫。语码转换反映了劳伦斯男女二元对立的哲学思想。