环境因素对复合绝缘子积污特性的影响

复合绝缘子在电力系统中被广泛应用,研究复合绝缘子积污特性与影响因素对降低绝缘子污闪事故的发生有着重要意义。基于FXBW4-10/100型复合绝缘子,建立了欧拉双相流绝缘子积污模型,对不同风速、粒径、浓度下绝缘子的表面积污特性进行研究。结果表明：污秽颗粒主要集中在绝缘子的迎风侧以及背风侧,绝缘子侧风侧积污较少;下表面积污体积分数高于上表面;随着风速的增加,绝缘子迎风侧与背风侧积污体积分数逐渐增大,侧风侧的积污体积分数先增加后减小;绝缘子表面的污秽程度随颗粒浓度的增加近似呈线性增加,整体积污均呈伞形分布;背风侧的积污程度随着颗粒粒径的增加呈现先增大后减小的情况。     

兰州城区街道峡谷内流场及机动车排放污染物扩散规律研究

利用数值模拟方法对兰州城区街道峡谷内流场及机动车排放污染物扩散特征与街道峡谷风场、几何结构及两侧建筑物对称性这间的复杂关系进行了数值实验。结果表明：在街道峡谷特殊地形和当地气象条件共同作用影响之下，峡谷内会形成一个完整的涡旋流场，其强度随着街道两侧建筑物屋顶来流强度的增大而增大，机动车排放污染物浓度的高层建筑物背风面及街道地面产生堆积，形成高浓度区，随着建筑物屋顶来流风速的增大，涡旋强度增大，湍流混合加强，大气扩散速率增大，峡谷内污染物浓度相对减小。     

障碍物对孤立山丘三维风场的影响

采用数值计算软件FLUENT研究障碍物的尺寸、障碍物与山坡坡底的距离对山丘风场的影响.根据计算结果绘制山顶上方50m处的湍流强度和速度变化图,山丘表面风速值线图以及来流方向分风速等值线图.分析结果表明:障碍物越高,距离山坡坡底越近,山顶风速减小幅度越大,越不稳定;山丘上游存在障碍物时,迎风坡和背风坡均出现低速区;障碍物距离山坡坡底较近时,迎风面上还出现了回流现象.迎风面、背风面的速度变化较大,不适合安装风力机;山丘两侧风速一直变化不大,比较适合安装风力机.     

带斜顶建筑物的城市街道峡谷内部气流场数值研究

基于S.R afa ilid is和M.Schatzm ann在风洞中所采用的城市街道峡谷物理模型,数值模拟了6种带有斜顶建筑物的城市街道峡谷内部气流场。模拟结果表明:①建筑物斜顶显著影响峡谷内部的气流场,由于气流绕过斜顶时产生剧烈分离,使得处于背风面的斜顶与处于迎风面的斜顶相比,前者对峡谷内部的气流漩涡结构影响更大;②斜顶建筑物高度与峡谷宽度的比是决定峡谷内部漩涡结构的重要因素,其比值愈大愈易于在峡谷内部生成两个旋转方向相反的漩涡(其中峡谷上部为顺时针漩涡,而下部为逆时针漩涡)。     

横向双极静电除尘器空气动力增效

为明确横向双极静电除尘器的空气动力增效机理,基于电除尘器的经典效率公式研究了空气动力对横向双极静电除尘器除尘效率的影响。数值模拟结果表明：横向双极电除尘器内荷电粒子的驱进速度是电场驱进速度与空气动力驱进速度之和。极板迎风面的空气动力增效幅度强于背风面,而极板背风面的低速回流区是主要的收尘区。实验结果表明：空气动力驱进速度与电场风速呈二次曲线分布关系。电场风速小于1.5 m/s时,气流运动强化了空气动力增效幅度;而电场风速大于1.5 m/s后,二次扬尘作用减弱了空气动力增效幅度。横向双极电除尘器除尘效率修正公式表明：在横向双极电除尘器结构参数一定的情况下,除尘效率受静电力和空气动力的共同影响。     

建筑体型廓线对建筑物表面粒子沉积特性的影响

选取典型建筑体型,利用计算流体力学方法研究了建筑体型对气溶胶粒子在建筑表面沉积速度和沉积通量的影响.结果表明:迎风面宽度是影响气溶胶粒子在建筑表面沉积速度和沉积通量的重要因素,且迎风面和背风面对其的影响规律不同;建筑表面上气溶胶粒子的沉积通量随着其粒径的变化而变化,且不同建筑表面最小沉积通量对应的粒径不同.     

包兰铁路沙坡头段防护体系近地面流场特征

基于地形和流场实测，研究了包兰铁路沙坡头段铁路防护体系近地面流场沿NNW-SSE方向的变化．结果表明，由于地形变化以及人工植被和草方格的存在，防护带内等风速线沿风向呈逐渐变疏和抬高的趋势，各高度的风速总体上呈递减趋势，风速放大率为负；沙丘迎风坡风速放大率为正，流动沙丘迎风坡风速放大率高于固定沙丘迎风坡．沙丘背风坡2．5m高度内风速放大率总体为负．防护带内的固定沙丘背风坡气流通体减速，各高度的风速放大率全部为负，平均为一1．48％／m．防护带内地表空气动力学特征发生变化，其中沙丘迎风坡地表风速廓线接近于对数率；人工植被带地表空气动力学粗糙度显著高于流沙区．     

风电机组塔筒结构绕流风场的数值模拟研究

为研究风电机组塔筒结构的气动力特性,基于ANSYS软件,建立了塔筒结构的简化模型并对其进行绕流风场的数值模拟分析,主要探讨了塔筒结构表面风压分布特征,风场风速、湍流度及不同高度比对塔筒表面风压分布的影响.结果显示,圆锥塔筒结构背风面在绕流作用下沿高度方向由上向下形成连续几个回流区,导致背风面受到正压作用;不同风速只有对塔筒背风表面压力大小有较之明显影响,而对塔筒迎风面及侧风面压力大小影响很小;湍流强度对模型表面风压系数大小有不同程度的影响,随着湍流强度的增加,模型侧面(大部区域)、背风表面的压力绝对值相应减小;不同高度比对模型表面风压分布有显著影响.研究结论可为风力发电机塔筒结构的设计提供参考.     

中继法解决临近空间Ka波段通信黑障问题

为解决航天器在临近空间的通信黑障问题,根据ARD等实测数据,分别建立再入航天器迎风面、背风面均匀等离子鞘套模型,分析再入航天器迎风面、背风面的等离子鞘套厚度、电子密度、等离子体碰撞频率等参数对Ka波段的传输透射率、反射率和衰减值的影响。分析结果表明:Ka波段工作信号在航天器背风面传输显著优越于在航天器迎风面传输,在航天器再入过程中,提高信号通信频段以及Ka波段工作信号从背风面传输的透射率相比从迎风面传输的透射率至少提高88%,衰减值至少降低19dB,为研究再入航天器通信问题提供了理论参考。     

低矮建筑非定常绕流大涡模拟影响因素研究

掌握结构周围风场及其特性,是开展建筑结构抗风设计的基础。借助采用大涡模拟（LES）的方法,对低矮建筑非定常绕流进行了大涡数值模拟研究,分别分析了不同运算时间、建筑物不同高度处及不同风速因素,对低矮建筑非定常绕流特性的影响。结果表明：（1）随着时间的增加,建筑物迎风侧的速度和压力均增大,背风侧的压力出现了负值,速度最小值出现在背风侧的涡中心位置;（2）随着建筑物高度逐渐增加,涡的位置逐渐向上偏移,由于风速比较均匀,当遇到建筑物时,在建筑物迎风侧,速度流线会形成一种上升的趋势,背风侧的压力逐渐增加;（3）随着风速的增加,建筑物的背风侧出现了大涡且速度逐渐增大,背风侧的压力最小值逐渐减小。     

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.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

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.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

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.     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.