Non-Steady Equilibrium during Pro-Eutectoid Ferrite Formation in Fe-0.2C Alloy

Ｔｈｅｐｒｅｃｉｐｉｔａｔｉｏｎｏｆｐｒｏ ｅｕｔｅｃｔｏｉｄｆｅｒｒｉｔｅｆｒｏｍａｕｓｔｅｎｉｔｅｉｓｃｏｎｔｒｏｌｌｅｄｂｙｄｉｆｆｕｓｉｏｎｉｎＦｅ Ｃａｌｌｏｙｓ .Ｗｉｔｈｔｈｅａｓｓｕｍｐｔｉｏｎｔｈａｔｔｈｅｍｉｇｒａｔｉｎｇｉｎｔｅｒｆａｃｅｉｓａｌｗａｙｓｉｎｌｏｃａｌｅｑｕｉｌｉｂｒｉｕｍ ,ｅａｒｌｙｉｎ 194 9,ＺｅｎｅｒＣ[1] ｅｘｐｌａｉｎｅｄｔｈｅｄｉｆｆｕｓｉｏｎａｌｇｒｏｗｔｈｏｆｐｒｏ ｅｕｔｅｃ ｔｏｉｄｆｅｒｒｉｔｅｂｙｕｓｉｎｇｔｈｅＦｉｃｋ’ｓｌａｗ .Ｓｉｎｃｅ…     

田口-灰关联法应用于Inconel 718微放电铣削参数最佳化(英文)

应用田口-灰关联法对Inconel 718微放电铣削多重质量特性如电极消耗率、材料去除率和扩口量进行最佳化,分析放电电流、脉冲时间、休止时间和极间间隙对加工Inconel 718之电极消耗率、材料去除率和扩口量的影响。实验结果表明,以最佳微放电铣削参数进行加工,其电极消耗率由5.6×10-9mm3/min降低到5.2×10-9mm3/min,材料去除率由0.47×10-8mm3/min增加到1.68×10-8mm3/min,扩口量由1.27μm降低到1.19μm。研究结果显示,应用田口-灰关联法,可以改善微放电铣削多重质量特性。     

高尔夫球头材质综述

高尔夫球运动是一项经过数个世纪的演变历史悠久的运动。一套高尔夫球具通常会准备不同功能的14支球杆,以便在多变且复杂的高尔夫球场上打出最少杆数。近23年以来将近有60几种的材料用于高尔夫球具,大致上可分为钛合金、不锈钢、碳钢、铜合金及非金属材料。文章综述了高尔夫球头的打击面所用材质,并分析其力学性能和特性演变。木杆头主要应用材料为钛合金,比强度介于（1.92.25）×104 MPa/（g·cm-3）,延伸率介于10%20%,密度介于4.374.5 g/cm3,杨氏模量介于110120 GPa。球道木杆主要应用材料为高强度不锈钢,比强度介于（178303）×104 MPa/（g·cm-3）,延伸率介于9%16%。铁杆头主要应用材料为不锈钢及碳钢,机械性质有高比强度（1.82.4）×104 MPa/（g·cm-3）及高延伸率（30%50%）的特性。推杆比强度不超过1.1×104 MPa/（g·cm-3）,延伸率则介于4...     

Pole assignment using dynamic output feedback compensators

The design of dynamic output feedback compensators for the pole assignment of linear time-invariant multivariable systems is considered. A systematic procedure is developed for the synthesis of the transfer function matrix of the compensator. A certain number of poles can be arbitrarily assigned by the proposed compensator. Moreover, in order to assign more poles using a compensator of the same order as before, a new approximate assignment approach based on the least-square-error algorithm is proposed. A numerical example is given to demonstrate the effectiveness of the proposed approaches.     

Convergence of the block-pulse series solution of a linear distributed parameter system

The convergence of the block-pulse series expansion of a function f(x, y) and its integral with respect to x and y is proved first. Then the convergence of the block-pulse series solution of a distributed parameter system obtained by the block-pulse series expansion method is proved.     

Landing domain analysis of shuttle re-entry vehicles

With increasing frequency in space shuttle operation, it is of interest to have more than one or two landing fields within the boundary of the reachable area of the reentry vehicle. This boundary, called the footprint, depends on the aerodynamic characteristics of the vehicle. It has been investigated previously but unfortunately was not completely constructed, especially the minimum range on the longitudinal axis and the left end portion of the footprint. In this paper, the previous work using the facilities of the continuation method and the multiple shooting method is extended, and a complete footprint is constucted. At first, the optimal trajectories are solved in the vertical plane and in the three-dimensional space to minimize the final range on the longitudinal axis, θ _{? min},. After comparison of the obtained minimum longitudinal ranges, we find that the three-dimensional optimal trajectory is the global optimal trajectory for θ _{? min},. With the application of the techniques of rotating the coordinates, based on this θ _{? min}, we obtain the complete footprint by the optimal lift and bank modulations for three-dimensional re–entry trajectories with lift constraint.     

Swelling and Gas Release in ZnO

Swelling and gas release in a model ceramic system, ZnO, were studied under known internal and external pressures, oxygen partial pressures, and temperatures. When gas was not released, the instantaneous swelling strain rate was: εα( DF exp-Q/RT) where DF is the instantaneous pressure driving force for swelling, Q = 141 ± 13 kcal/mol, and RT has its usual meaning. For a fixed initial driving force for swelling, the strain rate decreased as t^−1/3 where t is time. Volumetric swelling strains of ≥ 11% were measured prior to gas release, indicating that swelling is not simply reversed sintering. Gas release was usually observed and occurred by the interconnection of inter-granular porosity. A resintering process immediately followed gas release, but at a slower rate than the initial sintering rate at the same density. Analysis of the swelling experiments yielded a surface energy of ∼0.3 J/m² at 920°C for ZnO.     

ANISOTHERMAL TRANSFORMATION OF AUSTENITE

在珠光体转变的温度范围内,除下珠光体区域的停留促进上珠光体区的形核过程外,奥氏体在非连续冷却时,转变的形核过程具有相加性。在下珠光体区的形核过程中,可能先形成与奥氏体共格的核胚。 在贝菌体转变的温度范围内,较高温度的停留延缓较低温度时的形核过程,延缓作用随温度间隔及停留时间的增加而增大。较低温度的停留促进较高温度时的形核过程,促进作用随温度间隔的增加而增大,但随时间的延长而减小。建议贝茵体的核胚和马氏体的相同,即位错圈所包围的体心立方结构区域。 下珠光体区停留促进贝茵体的形核过程。     

FISH OIL WITH ESSENCE OF CHICKEN DECREASES SERUM AND HEPATIC TRIACYLGLYCEROL IN HAMSTERS FED AN ATHEROGENIC DIET

The aim of the present study was to investigate the effect of a mixture of dietary chicken essence and fish oil on possible lowering of blood and hepatic lipids in hamsters. Forty male hamsters were randomly divided into four groups and fed a chow diet, high fat/cholesterol diet (HFC), HFC diets containing 4% (HFC4) or 8% (HFC8) fish oil with essence of chicken for 42 days. The experimental diets contained 10% (w/w) fat. Hamsters fed HFC diets containing either 4 or 8% fish oil with essence of chicken showed significantly decreased serum triacylglycerols (TG) compared to hamsters fed HFC diets. In addition, hamsters fed HFC8 diets exhibited significantly reduced hepatic TG than those fed HFC diet. However, hamsters fed HFC4 or HFC8 diets significantly increased low density lipoprotein cholesterol (LDL-C) and decreased high density lipoprotein cholesterol (HDL-C) when compared with those on HFC diet. These results suggest that 4% (or more) fish oil with essence of chicken might significantly lower serum TG and hepatic TG in hamsters, but seem to increase serum cholesterol levels on HFC diets.     

EFFECT OF REARING CONDITIONS ON PRODUCTION OF STERNAL GLAND SECRETION,AND IDENTIFICATION OF MINOR COMPONENTS IN THE STERNAL GLAND SECRETION OF THE PREDATORY STINK BUG <Emphasis Type="Italic">Eocanthecona furcellata</Emphasis>

Production of the male specific compound, 6,10,13-trimethyltetra- decyl isovalerate by the predatory stink bug Eocanthecona furcellata (Wolff) was dramatically affected by rearing conditions. Male bugs kept isolated after eclosion produced an average of 1,948 ng of 6,10,13-trimethyltetradecyl isovalerate per bug, whereas male bugs reared in groups of 5–8 bugs produced an average of only 4 ng of 6,10,13-trimethyltetradecyl isovalerate per bug. Same-sex or mixed-sex pairs of bugs produced less than 50 ng per bug. Male bugs kept isolated for 1~wk and then grouped for 1~wk produced 3 ng of 6,10,13-trimethyltetradecyl isovalerate per bug, whereas male bugs grouped first and then isolated produced 135 ng of 6,10,13-trimethyltetradecyl isovalerate. A total of 11 minor components in relative amounts of less than 1% of the major 6,10,13-trimethyltetradecyl isovalerate were found in the sternal gland secretion. These included 6,10,13-trimethyltetradecanol, acetate, propionate, and butyrate esters of 6,10,13-trimethyltetradecanol, and isovalerate or valerate esters of homologs of 6,10,13-trimethyltetradecanol.