基于双齿面传动误差的侧隙连续测量与预测

提出了基于双偏心误差齿轮副的驱动齿面与齿背面（双齿面）无负载传动误差计算模型,建立与时变侧隙计算公式的等价关系,从理论上证明了基于双齿面传动误差的侧隙测量方法。通过实验方法测量不同负载力矩、不同初始啮合面的双面传动误差并获得相应载荷下的初始回差。基于双齿面传动误差实验曲线,实现了对齿轮副整个大周期侧隙的连续测量与预测。结果表明,连续侧隙曲线与机械滞后回差法测量结果吻合良好,而侧隙预测较好地反应了侧隙值变化范围和变化趋势。同时,侧隙连续测量方法及侧隙预测均证明了理论模型的正确性,提高了侧隙测量效率并获得了更全面的侧隙数据,对齿轮传动的非线性研究、消隙控制以及齿轮精度研究等均具有指导意义和参考价值。      

改善弧齿锥齿轮齿面接触区的加工方法

改善弧齿锥齿轮齿面接触区,提高锥齿轮的啮合性能,是保证轮齿质量的关键。 1.零度弧齿锥齿轮接触区修正 与直齿锥齿轮相比,弧齿锥齿轮齿与齿的啮合状态好,轮齿强度高,重合度也可加大。它适于高速、高负载运转。近年来,不少用户为改善锥齿轮传动中的噪音和工作平稳性,常把机械传动中的直齿锥齿轮改为零度弧齿锥齿轮(以下简称零度齿)。过去使用12″铣齿刀盘切齿,接触区很难调整好。后来,我改用9″刀盘,计算调整卡切齿,调接触区,缩小了刀盘直径,使切出的齿形较12″刀盘切出的“弯”些,虽然齿中点螺旋角基本不变,但加大了齿小端和大端的螺旋角,使接触区由原来灵敏度高、难调变得较易调整。根据铣齿工反映,一套零度齿(三     

新型摆线转子泵啮合特性的研究

对一种新型圆弧摆线内啮合转子泵进行了研究.新型转子泵在保证连续传动的基础上,将密封与传动的功能赋予齿廓的不同部分,从而避免了内转子的每个齿始终与外转子接触,使得其啮合特性得到极大改善--从根本上消除了普通转子泵所特有的外转子滑动系数出现极大值的现象,并使啮合角的变化范围更加合理.与普通转子泵相比,新型转子泵大大减少了磨损,降低了对转子制造安装精度的要求.因此,新型转子泵可以采用较普通转子泵更高的工作转速、更多的齿数,并获得更大的流量、更小的波动和更小的磨损.分析了新型圆弧摆线内啮合转子泵内外转子齿廓的构成及啮合原理,并与普通摆线转子泵进行了啮合特性对比分析.     

啮合齿轮的模数和齿数的合理选择

齿轮强度的校核计算可以得出，在保证啮合齿轮中心距不变、传动速比相近似的情况下，通过合理减小啮合齿轮模数和增加啮合齿轮齿数的方法，可以适量提高啮合齿轮的齿面接触强度。在实际应用中，用上述方法对啮合齿轮进行设计改进，可以解决齿轮由点蚀而引发疲劳失效的问题。     

消除齿侧间隙的几种措施

就消除一对啮合齿轮齿侧间隙的几种方法加以论述．并推导出消除多级啮合齿轮齿侧间隙的方法，供设计、改造冶金、矿山设备参考。     

弧齿锥齿轮在φ2.2M圆锥破碎机的应用

φ2.2M弹簧圆锥破碎机传动轴部的传动齿轮为直齿锥齿轮传动,相互啮合的轮齿是线接触,由于齿轮制造,安装的误差以及传动时的变形,容易产生仅轮齿一端接触的现象,从而引起载荷集中,传动不平稳,承载能力低,传动效率也比较低,容易产生断齿等现象.通过改造直齿锥齿轮传动为格里森弧齿锥齿轮传动,提高齿轮的重合度,从而增大了接触比,减轻了冲击,使传动更平稳,并且降低了噪音:负荷比压降低,磨损较均匀,相应增大了齿轮的负载能力,使用寿命更长:并且可以进行齿面的研磨,以降低噪音,改善接触区和提高齿面光洁度.     

基于模糊综合决策的直齿圆柱齿轮齿廓最佳修形

在时变啮合刚度和Blok闪温理论的基础之上,系统地分析齿廓修形参数对齿间载荷分配、传动误差和齿面闪温的影响,并确定在单目标条件下齿廓修形的最佳修形参数.基于模糊综合决策理论,确定了综合考虑多目标条件下齿廓修形最佳修形参数.引入多目标条件下修形量的修正系数X_c,确定修正系数X_c的值,并给出多目标条件下修形量的计算公式.综合最佳修形参数的最大修形量,取单双齿啮合区交替点B和D的变形量乘以修正系数X_c,修形指数取1.43,修形方式为长修形.      

BUSS混捏机G160减速机锥齿轮齿间隙的调整

BUSS连续混捏机G160减速机机体庞大,齿间隙调整复杂,作业困难。本文主要通过对圆柱直齿轮副几何分析及相关公式推导,利用类比法得出圆锥齿轮副的啮合关系,进而导出其中某一齿轮轴向移动量与啮合间隙变化量之间的函数关系,为准确、高效地调整G160减速机齿间隙提供理论依据。     

如何消除球磨机大小新旧齿轮啮合振动

球磨机是选矿公司生产的主要设备,多金属选别作业区球磨机自投产已使用40多年,球磨机大齿轮磨损。因受到厂房高度和起吊设施吨位限制,作业区球磨机很难整体更换新大齿轮。在更换了新的小齿轮后,因大齿轮齿面已磨损,造成齿形误差,齿廓不是“严格”的渐开线,新旧大小齿轮啮合造成啮合冲击,出现强烈振动,甚至出现小齿轮轴断轴现象。本文主要介绍球磨机新旧大小齿轮啮合后振动强烈时,通过现场对齿面啮合情况观察和分析,找出产生振动的主要原因。依据大小齿轮啮合情况,适当放大大小齿轮啮合的齿顶间隙,避免顶齿现象,消除振动,降低噪音,延长小齿轮及轴承的使用寿命,确保安全平稳生产,也为以后类似检修过程积累经验。     

大中型齿式联轴器的保护性拆卸

通过一台轧机主传动齿轮座输入轴齿式联轴器外齿圈的成功拆卸的例子,阐述了现场采用传统方法对大中型齿式联轴器进行保护性拆除的理论计算方法与工艺要点。     

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.     

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。     

抗腐蚀高强耐磨涂料研发与应用

介绍了抗腐蚀高强度耐磨涂料的研制和开发，以及用作柳钢球团回转烘干机刮板保护涂层的应用效果。