Dealing with Thermal Exchange in Temperature Field Simulation in Low Pressure Die-casting Process

The main effort is to develop numerical simulation software of low pressure die casting on Windows platform in Personal Computer, based on the production of aluminum wheel in Die cast wheel manufacture Co. Ltd.. The heat conduction calculation is the basis of solidification simulation. A 3 dimentional model including the refrigeration medium block is set up based on the study of boundary heat exchange. Various calculation method is analyzed for different types of boundary element. A comprehensive calculation model is set up according to practically manipulable parameters in production.     

Connect Technique of Laminated Object Manufacturing Using Metallic Materials as Modeling Materials

To solve some key problems existed in the manufacturing of metallic functional part via Laminated Object Manufacturing (LOM), a new technique using vacuum solid-state pressure diffusion weld technique to connect the metallic slice sheets is presented in this paper. The following conclusions can be draw from the experiments introduced specially: the size in the stack direction shrink at the rate of less than 1% and the shrinking is owed to regularly error, the atom-diffusion between two combined interface occurred clearly and new crystallites shaped meanwhile, shearing intension of well connected diffusion section is more than 100 MPa and micro hardness of well-knit portion is the same to matrix's. It can be proved from the result above that the vacuum solid-state pressure diffusion technique weld is a perfect technique for connecting metallic slice sheets used in the manufacturing of metallic functional part via LOM.     

Study on the Sand Duct Pressure and Energy Dissipation for Tongkou Hydro Power Station

Tongkou power station is an all-round hydro project,where the mixed exploitation mode is adopted with mainly for power generation.Integrated with the model test result,the duct discharge capacity and flow coefficient in various discharge hole are discussed,the influence of duct shape on inlet pressure,energy dissipation and tail water is analyzed,the improvement measures on conveyer way pressure and energy dissipation are put forward too.The achievements of this study have been adopted by the designers.     

增压溶样—ICP—AES法同时测定茶叶中多种微量元素含量的研究

研究了增压溶样-ICP-AES法同时测定茶叶中Al,As,Ba,Cd,Cu,Fe,Mn,Ni,Pb,Se和Zn等12种矿质营养元素及重金属元素,确定仪器最佳工作参数,并对基体干扰及共存元素的光谱干扰等进行了探讨。方法准确度、精密度符合痕量分析要求;灵敏度适合进行茶叶分析。     

高压对水稻种子萌发的影响

以籼稻品种粤丰占、粳稻品种秋光、粤丰占的高压后代压诱1号和压诱2号的种子为材料，研究了高压处理对不同浸种时间种子萌发的影响。结果表明：高压处理后，所有品种种子的发芽势和发芽率均随处理压力的升高而降低；相同的压力处理后，发芽势和发芽率在同一品种不同浸种时间的种子之间也存在显著差异；相同高压条件下秋光的发芽势和发芽率都比粤丰占的高；高压后代压诱1号和压诱2号种子对高压的耐受性与非高压后代粤丰占种子的没有显著差异，说明高压能够影响种子的萌发，并且不同类型的水稻品种种子的耐压性不同，高压处理不能明显提高其后代的耐压性。     

食品工程用超高压设备的设计及性能试验

为了提高超高压设备的稳定性和处理效率,促进超高压技术应用于食品加工,该文阐述了HHP-700-400L型食品工程用大型超高压设备的工作原理、设计要求、主体结构和工作过程,分析并确定了双向水介质增压器、直推式容器堵头及其密封系统、承压容器材料和结构等相关参数。设备单体容积为100L,总容积为400L;最高工作压力为600MPa;处理能力达到1.68t/h。经性能试验表明:设备性能稳定、操作方便、安全可靠。研究结果为大型商业化超高压设备的设计和制造提供参考。     

基于空间信息技术的县域生态环境监测与评价

[目的]探究生态环境监测数据精准获取方法,构建生态环境质量评价指标体系,为生态环境精准保护提供科学依据。[方法]基于多源遥感影像数据,利用InVEST模型、裸土植被指数模型、综合指数法等多种模型与方法,从生态系统质量、生态系统服务、生境压力和环境质量4项一级指标及植被覆盖度、固碳能力、道路压力指数、霾指数等14项二级指标分析河北省阜平县生态环境质量。[结果](1)生态系统质量一般和较差区分布最广,集中在东部水库区和西部中山、低山区。(2)生态系统服务较差区面积最大,主要分布在县中部和东部。(3)生境压力较差区比例最高,以未利用地为主。(4)环境质量为良的区域在全域均有大面积分布。(5)阜平县生态环境质量整体较好,一般区广泛分布,占总面积的77.04%,主要为耕地、草地和未利用地。[结论]基于空间信息技术与多源遥感数据的生态环境监测与评价方法可以快速、有效地反映县域生态环境质量。     

Pulmonary artery wedge pressure during treadmill exercise in warmblood horses with atrial fibrillation

The heart rate and the pulmonary artery wedge pressure (PWP) was measured in 10 healthy warmblood horses and in six warmblood horses with atrial fibrillation (AF) at rest and during standardised treadmill exercise. During treadmill exercise, the increase in heart rate was significantly higher in the horses with AF than in the healthy horses. Horses with AF showed a significantly higher increase in PWP at treadmill velocities of 5m/s and faster, than did the healthy horses. The differences in PWP between both groups increased with treadmill strain. The present study demonstrates that there is an influence on the haemodynamics in horses with AF during treadmill exercise, which could explain exercise intolerance in some horses with lone AF.     

Controls on latent heat flux and energy partitioning at a peat bog in eastern Canada

Surface and atmospheric controls on latent heat flux (Q_E) and energy partitioning were assessed during three growing seasons at the Mer Bleue peat bog. The surface consisted of a sparse canopy (maximum leaf area index 1.3) of low, mostly evergreen shrubs over moss-covered hummocks and hollows. Available energy was partitioned mostly to Q_E (Bowen ratio often less than 0.5) throughout the growing seasons over an extensive range of water table fluctuation (as much as 50 cm). Q_E was often at or below the equilibrium rate due to surface (low moss water content, strong vascular stomatal control) and/or atmospheric (low vapour pressure deficit (D_a)) factors. Turbulent energy fluxes varied with net radiation and the magnitude of the fluctuations were affected by D_a and moss water content. It is suggested that a change in source partitioning for Q_E led to a change in Q_E − D_a dynamics. Early in the growing season the moss was wet and the vascular canopy was replacing leaves, thus Q_E increased as D_a increased because moss, which reacts passively to D_a, contributed strongly to Q_E. Later in the growing season as water table declined and the evaporation load reduced moss and fibric peat water contents, moss contributed less strongly to Q_E and vascular contribution became more important. Also, stomatal control became more influential in reducing bulk surface conductance for water vapour and Q_E in response to increasing D_a.     

稀释液溶质和渗透压对鸡精液低温保存效果的影响

观察15种物质不同渗透压（300mOsm、400mOsm、500mOsm）对鸡精子低温保存的精子活力、生存指数、存活时间和30h精子畸形率的影响。结果表明,对鸡精子低温保存生存指数大于50的物质由高到低依次为果糖、甘露醇、谷氨酸钠、山梨醇和氯化钾;精子总存活时间大于120h的物质由高到低依次是果糖、甘露醇、谷氨酸钠、山梨醇、氯化钾、磷檬酸钠和乙酸钾;30h精子畸形率小于0．2的物质由低到高依次为L-谷氨酸钠、甘露醇、蔗糖、乳糖。渗透压分析结果表明,各指标均随渗透压升高而降低。在300mOsm时,30h精子畸形率、精子生存指数和存活时间均极显著高。