铝电解大功率整流供电系统稳定性技术研究

在大型铝电解企业生产过程中一旦整流供电间断,将带来严重的经济损失.通过对铝电解大功率整流供电系统稳定性进行研究分析,结合实际运行中的关键问题,提出了提高铝电解整流供电系统稳定性的有效策略,保障整流供电系统安全经济稳定运行.     

进口铝电解整流变压器总烃严重超标的原因及其消除

针对引进BBC公司铝电解整流变压器油中总烃含量严重超标问题，分析产生可燃性气体的原因，指出变压器内部存在的缺陷和故障部位，经过改造处理，消除了故障点，降低了油中产气速率，使之安全可靠运行。     

鞍钢供电系统高次谐波的危害及其应采取的对策

近十年来,为适应鞍钢的技术改造,不断地采用了可控硅整流装置。这些运行在供电系统的可控硅整流装置,在某种意义上讲就是个高次谐波发生器。这些高次谐波对各种用电设备会产生许多不良影响,如使电气设备产生过载、过热;使电压波形畸变,影响控制装置等。对变压器、电容器、电机等也有不利影响。因此,必须采取相应的对策。在安装可控硅整流设备的同时,安装消除谐波的滤波装置,以消除谐波,保证供电系统安全、可靠的运行。     

铝行业大容量整流电源保护综述

大容量整流电源通常由变压器、整流柜及用于整流柜、变压器冷却的泵、风机等辅机部分组成。大容量整流电源在冶金行业,特别在铝电解行业具有举足轻重的地位,其正常运行直接关系到整个生产系列的安全稳定,一个年产15万吨的电解系列,停电5个小时其损失可达几千万元,因此,要采取一切可能的措施保证整流电源的正常运行,完善、可靠的保护设置可以及早发现机组异常情况,及时切除故障,防止事故扩大,对保证系统安全运行具有重要意义,下面对大容量整流电源所需设置的保护作具体介绍:电压保护Voltage protection 1.采用氧化锌压敏电阻、快熔组成过压吸收回路,吸收电网过电压、操作过电压以及雷电过电压,由快熔所带的微动开关发出故障信号。     

基于变压器在线监测技术检测研究

随着供电系统逐渐向特高压、大容量等方面发展,及社会的发展趋势和对电源安全性要求的增加,重要设备突发故障的预防、监测及控制是确保可靠供电的重要手段。电力系统中电力变压器的正常运行对电网运行、用户供电有着极其重要的作用。所以,即时并定期地在线监控电力变压器的工作状况,以及时发现变压器设备早期绝缘问题,从而防止事故发生,缩短了不必要的停电维护和时间,增强电源安全性,防止电气设备非正常停机,对电网的安全运营和用户的安全供电都有着重要意义。本文分析了电力变压器常见的故障,提出了变压器故障在线监测方式。     

电弧光保护装置在电解铝行业硅整流柜中的应用特点

硅整流装置是电解铝供电整流系统中的主体设备。整流柜发生弧光短路事故给企业带来巨大损失,而现有的保护系统不能满足整流机组快速切除弧光故障和保护覆盖范围的要求。包铝股份供电公司结合行业特点和整流供电系统存在的特殊情况,在电弧光保护装置的应用过程中开发出了不同于普通配电系统的电弧光保护装置,在电弧光保护系统应用方面形成了独特的技术,弥补了电解铝整流系统的保护设计缺陷。     

引进整流变压器存在的问题及处理方法

介绍引进整流变压器的基本结构,通过对故障情况下变压器事故分析,解决了变压器结构上存在的严重问题,介绍了处理过程中采取的措施。     

铝电解引进大型整流变压器技术交流会在青海铝厂召开

铝电解引进大型整流变压器技术交流会在青海铝厂召开１９９５年９月２７～２８日，受中国有色金属工业总公司委托，结合我国铝冶炼生产企业引进整流变压器的运行情况及青海铝厂一期引进ＢＢＣ公司的３＃整流变压器（１１５ｋＶ直降、调主合一、ＴＵ型有载开关调压，型号：...     

电解铝整流柜事故浅析

近年来随着国内整流行业相关设备的装备技术水平不断提高，整流机组运行相对趋于稳定，但从现已投运的大电流机组看仍然暴露出不少的问题，尤其在整流供电设备方面，已经出现了许多设备事故，造成这一局面的因素很多，但设备因素是导致事故发生的主要原因，我们通过分析研究对大电流整流机组采取了一系列的措施，有效地预防了整流柜事故的发生。     

浅析整流变压器中间回路跳闸原因

中国铝业青海分公司二期为大型预焙烧电解槽,直流系列电流为160kA,系列电压为1150V。为SIEMENS公司成套引进大型整流设备,于1993年投入运行。正常四台机组全部运行,设备检修时三台机组也可满足电解生产要求。由于设备老化和故障频繁,严重影响了对电解的正常可靠供电,于是2000年增加了第一台整流变压器给二期电解供电,但随着第九台变压器投入运行以来,“中间回路过流”引起二期整流变压器跳闸现象时有发生,给电解正常供电带来了新的隐患,因此,有必要明确“中间回路过流”跳闸的原因和采取的预防措施。     

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。