摆杆活齿传动啮合刚度分析

基于Hertz理论,分别建立了激波器活齿啮合副及活齿中心轮啮合副的啮合刚度模型,推导出啮合副啮合刚度计算公式,分析了各主要结构参数对啮合副啮合刚度的影响规律,对于改进结构设计及改善啮合性能具有指导意义.     

挖掘机斗齿的磨损机理与材质

在对矿山、工地、码头使用的挖掘机斗齿进行了测试和解剖的基础上 ,探讨了斗齿的失效机理 ,并分析了斗齿的形状、结构及材料     

微线段齿廓的非圆齿轮齿廓曲线及其图形仿真

在建立具有微线段齿廓的基本齿条数学模型基础上 ,应用齿轮啮合原理 (啮合方程 ) ,在齿轮坐标系中获得具有微线段齿廓的非圆齿轮齿廓曲线的数学模型。并用计算机图形仿真的方法 ,绘制出微线段齿廓的椭圆齿轮和高阶椭圆齿轮的齿廓曲线     

用球形滚刀滚切内齿轮

分析了球形滚刀滚切内齿轮的切削机理，探讨了齿槽断面的求解方法，用此方法在个人计算机上能高效率地绘制齿形创成图。分析表明，滚刀安装位置不影响滚切渐开线齿形。通过绘制齿形创成图，还可掌握各刀齿的切削负荷以及切屑的形状、厚度和长度。     

挖掘机斗齿复合生产工艺

挖掘机斗齿是挖掘机中的易磨损件,铸件要求齿尖高硬度,具有高耐磨性,其他部位有高的强韧性。基于真空熔模钢丸激冷振动复合铸造工艺,成功生产出高强度、高韧性挖掘机斗齿。经过热处理后,性能明显优于其他方法生产出的产品性能,硬度(HRC)为50,冲击韧度为21.3J.cm-2,抗拉强度为1673MPa,且获得了更多的马氏体组织。相对普通熔模铸件,耐磨性提高了70%。     

Fluoridated ground water and its toxic effects on domesticated animals residing in rural tribal areas of Rajasthan,India

Ground water sources (wells and handpumps) for drinking water in 12 villages of tribal areas of Rajasthan (India) were analysed for evidence of fluoride (F) content. These sources revealed mean F concentration in the range of 1.0 to 5.2 ppm. The toxic effects of fluoride (fluoride toxicity) in the form of osteo‐dental fluorosis were observed in the domesticated immature and mature animals, viz., cattle, buffaloes, goats and sheep. The prevalence of dental fluorosis in calves (< 1 year age) was found to be relatively higher than for adult cattle and buffaloes. Cent percent calves (7/7) were revealed with enamel mottling with varying grades at 3.0 ppm F concentration in ground water, whereas cattle (40/40) and buffaloes (14/14) were at 3.2 ppm. The older buffaloes showed brownish black teeth, not creamy yellow as found in calves and cattle. Out of 516 goats and 468 sheep and their 236 lambs, none showed evidence of osteo‐dental fluorosis. The overall prevalence of skeletal fluorosis was 36.2%, with the highest prevalence of 56.0% in cattle and 59.6% in buffaloes at a mean F concentration of 5.2 ppm. At or more 4.0 ppm F concentration only 28 (7.16%) buffalo calves were found to be affected with skeletal fluorosis. Intermittent lameness occurred in most of the higher age group of animals (>7 years age) at 1.8 ppm F or more in the water. None of the fluorotic animals was found to be affected with hypothyroidism. The prevalence and severity of osteo‐dental fluorosis in these animals was progressive with age. Different effects of fluoride toxicity in cattle and buffaloes are also discussed.     

悬臂打壳机行走蜗轮失效原因分析

分析蜗轮的受力，对接触应力、轮齿弯曲应力进行计算及校核，指出失效原因，提出解决办法。     

Chemical and structural composition of Atlantic Canadian moose (Alces alces) incisors with patterns of high breakage

Analysis of mammalian teeth can provide information regarding local environmental conditions. For example, a high incidence of breakage and wear within a population may indicate poor food quality. Individuals consuming a diet causing high mechanical stress on their teeth, and/or lacking the appropriate minerals for proper development, could experience degradation of tooth condition. Previously, we documented a high rate of incisor tooth breakage, with age, in two genetically distinct moose populations in Atlantic Canada. In this study, multi-element (¹¹B, ⁶³Cu, ⁶⁴Zn, ⁷⁵As, ⁸⁵Rb, ⁸⁸Sr, ¹¹¹Cd, ¹¹⁸Sn, ¹³⁷Ba, ²⁰⁸Pb, ²³²Th, and ²³⁸U) analyses using laser ablation ICP-MS were performed on moose incisors from multiple North American regions. The purpose was to determine whether the elemental composition of moose incisors varies among regions, and whether that variation is related to tooth degradation among Atlantic Canadian populations. A principal components analysis revealed that nearly 50% of the elemental variation in the inner enamel matrix of moose teeth was explained by three groupings of elements. The element groupings revealed differences among geographic regions, but did not explain the variation between incisors that were broken and those that were not. Regression models indicate that the elemental group which includes Cu, Pb, and Zn is related to decreases in incisal integrity. It is likely that other environmental factors contribute to the occurrence of increased incisor breakage in affected populations. The relationship between food resource quantity and quality, as a function of moose density, is hypothesized to explain loss of tooth integrity.     

谐波式齿轮泵的流量脉动分析

运用轮齿啮合理论几何运动规律对谐波式齿轮泵的流量特性进行研究,推导出了瞬时流量的计算公式,并与内啮合齿轮泵的流量脉动进行对比。     

Moisture and fat content,marbling level and color of boneless rib cut from Nellore steers varying in maturity and fatness

This study analyzed rib steaks (M. longissimus thoracis) of Nellore steers (n = 60) for intramuscular moisture and fat content, marbling level, and visual and instrumental color. Carcass sides were classified on the kill floor according to teeth maturity (2, 4 and 6 permanent incisors), and fatness (2 — slight and 3 — average). The cranial end of the boneless cut was aged for 14 days, and frozen. Steaks of 2.5 cm thick were cut and thawed for analysis. Moisture and fat content were determined in minced lean. CIE color was measured with a MiniScan XE™, and visually evaluated by an eight-member panel, which also assessed marbling. In this type of cattle and ranges of maturity and fatness considered, increasing either maturity or fatness causes a slight reduction in moisture and an increment in lipid content. But neither maturity nor fatness seems to affect the visual perception of meat color on display.