切纵流联合收割机清选室内气流场的模拟仿真

切纵流联合收割机存在损失率大和含杂率高等问题,为分析清选性能较低的原因,对切纵流清选室内气流场分布进行模拟仿真,运用CFD仿真软件对清选室气道气流进行分析.仿真结果表明,清选室内气流在筛面宽度方向呈对称分布,沿筛面高度方向气流速度逐渐减小,沿筛长度方向筛前段气流速度较低,在接近筛中部时气流速度达到最大.并对清选室内气流场进行了测量试验,验证了气流场仿真的准确性.     

木材干燥室内部风速场的数值模拟与优化

为了改善木材干燥室内部风速场的均匀性以提高干燥质量,对材堆到侧墙距离为0.30 m,风机风速分别为2.0、3.0、4.0 m/s的工况下木材干燥室内部风速场,采用Fluent进行数值模拟与分析,得到风速分布最佳时的工况。此外,在最优风速场工况下,通过改变材堆到侧墙距离(0.25、0.30、0.35 m),对试验结论进行验证。结果表明:对于顶风式木材干燥室,选择风机风速为3.0 m/s、材堆到侧墙距离0.30 m时,木材内部风速场最均匀,采用Fluent得到的模拟值与实际值相差不大。通过Fluent方法对木材干燥室内部风速场进行数值模拟,可有效优化风速场的均匀性。     

径向进气风扇与筛子配合性能的试验研究

用单因素试验和正交试验法研究了径向进气风扇与筛子的工作参数对清选性能的影响规律,获得了较优参数的组合。研究指出,径向进气风扇出口风速的分布特性有利于筛面风速的合理分布和谷粒的清选。性能试验表明,径向进气风扇与筛子配合具有良好的清选效果,其清选能力和性能指标高于传统的离心风扇。所研究的径向进气风扇模型可在脱粒机、清选机和大型联合收割机上实际应用。     

基于珠-杆模型的喷气涡流纺喷嘴气流场中的纤维运动规律

采用有限体积法对喷气涡流纺喷嘴中的高速气流场进行数值模拟,通过Fluent软件获得了喷嘴中气流场的流动特征,并对气流场中的纤维模型进行动力学分析,在此基础上建立纤维/气流力学模型,求解纤维运动方程,从而对纤维在涡流纺喷嘴气流场中的运动轨迹进行追踪.模拟结果表明:喷气涡流纺喷嘴内部气流呈中心对称分布,纤维在喷嘴内部呈波浪形运动,纤维尾端越靠近加捻室区域,其摆动越明显;当纤维全部进入空心管后摆动不明显.     

风力发电机叶片的转动特性分析研究

本文以流体力学为基础,利用Fluent对叶片周围的流体域数值计算,将风机转速、来流风速和转动力矩三个参数结合DOE方法进行响应面优化分析,为风机的转动特性分析、故障诊断和预报以及结构动力特性的优化设计提供相关数据.通过数值计算表明,风机转速与来流风速共同决定风机的转动力矩,进而影响风力发电机的功率.     

袋式除尘器流场动态测试及优化

采用热线风速仪及建立袋式除尘器实验装置对袋式除尘器内部流场气流分布进行测试,应用CFD对其气流分布进行数值模拟与实验对比。利用计算机模拟诊断得出流场分布不均匀产生的原因,提出流场改进措施及结构优化参数。研究结果表明:流场的不均匀性主要是入口风速过高和袋室的结构不合理造成的;计算机模拟结果与实验结果基本吻合,表明用CFD模拟方法替代试验进行流场的研究是可行的。     

沈阳某小区室外气流场模拟及室内环境相关性研究

目的研究建筑室外环境与室内环境的相关性,以期通过室外环境的优劣来分析建筑室内环境,使人们有一个较良好的室内生活环境.方法运用数值模拟Fluent软件模拟建筑室外气流场,得出在不同高度处小区风速及风压分布,通过分析不同高度处小区风速和风压的变化来研究建筑小区室外环境.结果建筑室外环境与室内环境有较大关联,建筑室外气流场的不同会直接影响建筑室内环境.结论模拟建筑室外气流场不仅可以评价建筑室外环境,而且对行人的日常出行会有一定的指导作用.     

风送式果园喷雾机气流场优化及试验

针对采用轴流风机的风送式果园喷雾机气流场分布难以和果树冠层区域喷雾要求相吻合的问题,提出一种风机气流场优化方法.通过在风机内部的中导流板、后导流板及出风口处添加并优化导风板的方法来提高气流场与果树冠层喷雾要求的匹配效果,以提升喷雾质量.通过Solid-Works、PolyWorks和Geomagic Studio共同建立风机三维模型,采用κ-ε湍流模型并利用Fluent软件进行气流场仿真分析,最后试制样机并进行实际气流速度的测量和对比.结果表明:通过优化导流装置后,喷雾机左、右侧气流速度在果树冠层最稠密的100～190 cm高度范围内平均气流速度分别提升29.1％和32.5％,有助于提升气流对果树冠层的穿透能力,提高喷雾效果.     

离心通风机内部流场数值模拟

为降低离心通风机的能耗,在不同体积流量参数条件下应用Fluent软件对WDLH-450型离心通风机内部流场进行了数值模拟,得到风机效率、总压力和叶轮功率等数据.结果表明,总压力和效率等性能参数的模拟结果与实验测量数值非常吻合,验证了数值模拟的正确性.由于风机叶片为不规则几何体,使得风机在工作时内部流场非常复杂,叶片旋转时会产生不规则的气流,形成蜗壳区域气体的二次流动和叶轮前盘区域的涡流,造成叶轮和蜗壳区域流动能量的损失.同时,各叶轮流道的流场由于气流流动分布的不均匀性而存在压力不对称的现象.     

QLJ500型清粮风机的设计计算

从能量的角度,推导出清粮风机的理论全压HT∞,考虑到风机工作时各种能量的损失,得出实际压力HT。计算出风机的空气流量Q,确定了出风口气流速度V,并以HT、Q、V为主要参数,依据风机在清粮机上的总体配置和传动设计要求,结合各种性能系数,计算出风机设计的主要数据。对设计制造出的风机进行了出风口风速均匀性能测试。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

正~~