大容量同步电动机的软起动控制

为了减小大容量同步电动机起动电流并缩短起动时间，提出用恒剩余角控制方法代替恒超前角控制方法，分析了恒剩余角数字控制系统中的一些主要问题： 稳定性、转子位置信号生成、逆变器控制及励磁控制，并给出了解决方法。用在线辨识方法获得的电机参数计算换流超前角，提高了计算的准确性。设计制作了一台７．８ Ｍ Ｗ 同步电动机软起动的数字控制系统。分析和现场运行表明，采用恒换流剩余角控制是减小起动电流并缩短起动时间的有效方法     

自控式同步电动机高性能控制方式的实现

分析了恒换流剩余角和恒气隙磁通控制相结合的高性能控制方式。提出了基于端电压相位检测的恒换流剩余角控制方法，讨论了端电压相位检测的低速运行问题。得出了计及气隙磁场饱和效应时恒气隙磁通控制的励磁调节规律，给出了一种无刷励磁结构及馈电主回路。采用８０８６微机与８０３１单片机构成的全数字控制系统实现了恒换流剩余角和恒气隙磁通控制。实验结果表明采用此控制方式的自控式同步电动机可获得最优性能指标。     

液压蓄能式风力机组并网转速解耦优化控制

针对在风速、同步发电机负载变化情况下,液压蓄能式风力机组并网转速控制问题,提出一种新型并网转速控制方法——解耦广义预测优化控制方法（Decoupled Generalized Predictive Optimization Control, DGPOC）.首先,DGPOC利用基于广义预测的前馈解耦方法解除变量马达摆角和蓄能器比例阀开度之间的耦合关系,进而调节蓄能器比例阀,依靠蓄能器吸收波动流量,同步调节变量马达摆角实现恒转速控制,解决因风速、同步发电机负载变化引起的变量马达转速波动问题; 其次,将蓄能器比例阀的能量损耗作为性能约束项,加入到优化目标函数中,求取最优控制量,从而提高液压蓄能式风力机组风能利用率; 最后,利用建立的MATLAB-AMESim联合仿真实验平台验证DGPOC方法的有效性.实验结果表明： DGPOC方法不仅可以实现变量马达摆角和蓄能器比例阀开度两个变量的解耦,提升变量马达转速控制的快速性及鲁棒性,而且能够降低系统的能量损耗.     

基于国产荧光分光光度计应用导数--恒能量同步荧光法测定苯并（a）芘

该方法利用同步荧光分析法中的导数-恒能量同步荧光法，基于上海棱光技术有限公司F97Pro荧光分光光度计产品，通过对食品样品进行简单的萃取处理，在选定的同步荧光扫描参数下直接测定，运用标准加入法定量计算，实现了对食品中苯并（a）芘的快速测定。该方法检出极限为0.1n g/g。     

新型扫描电镜分辨率的蒙特卡罗模拟

用蒙特卡罗方法模拟计算了利用高能同轴背散射电子的扫描电子显微镜的空间分辨率，点源模型的模拟结果显示小的入射能量、探测能量窗口及探测角值对应较好的分辨率，对由两种不同元素构成的边界而言，模拟结果显示：好的分辨率对应较小的探测能量窗口和较大的探测角，最佳的入射能量是10keV。在合理优化电镜工作参数的前提下，最佳空间分辨率可达束斑大小的量级。     

水中多环芳烃混合物快速恒能量同步荧光分析

建立了咔唑、1,2-苯并蒽、苯并[a]芘和2,3-苯并蒽四种多环芳烃同时快速测定的恒能量同步荧光分析法.选择能量差Δυ-=1400cm-1,仅需一次扫描,就可同时鉴别和定量测定四种多环芳烃.四种多环芳的线性范围依次为0.5-300ng·mL-1、0.2-250ng·mL-1、0.05-50ng·mL-1和0.5-350ng·mL-1,检出限在0.0046-0.023ng·mL-1之间.该方法简单快速、灵敏度高,无需对多环芳烃混合物进行预分离,可用于实际水样的直接分析,效果良好,回收率为83.0%-105.3%.     

同步锯齿波发生器电路的改进

利用NE555定时电路和恒流充电的积分单元电路，设计了一种线性良好的锯齿波发生电路；该电路克服了文献[1]中电路的缺点，实现了作为扫描电路所要求锯齿波的同步与良好的线性．     

凸轮驱动的液压全可变气门机构研究

考虑到电液式可变气门大多需要高响应性的电磁阀,成本高昂控制复杂,而目前市面上技术较为成熟且应用较广VVT和VVL技术,对于配气参数的调节是有限且有级的.作者设计了一种凸轮驱动的可变液压气门机构,并进行了台架试验研究.该可变液压气门机构的提前泄油量的调节可以使气门升程和关闭角同时可变,而延后压油量的调节可以使气门升程,开启角和关闭角均可变.结果表明,所设计的可变气门机构实现了气门开启角,关闭角和气门升程的配气参数全无极可变,并且该系统成本低廉、控制方便.      

红外导数光谱法测定二甲苯异构体含量

<正> 导数光谱法(Derivative Spectrometry)是近年来发展较为迅速的一种技术。早在50年代中期,Giese等就利用微分方法解决了光谱的重叠问题。随着现代电子技术的迅速发展,特别是分析仪器上使用了计算机,导数光谱的应用更为广泛。尤其在可见——紫外分光光度法中的应用更为突出。目前导数光谱法在红外     

同轴背散射电子相互作用体积的蒙特卡罗模拟

根据利用高能同轴背散射电子的扫描电子显微镜的工作原理，用蒙特卡罗方法模拟了电子束在样品中的相互作用范围，分析被探测电子的出射深度分布、计算了逸出面密度分布、平均进入深度和平均逸出距离，讨论了上述量与入射电子能量、能量损失窗口、探测角及样品体密度之间的关系，结果表明，入射电子能量、能量损失窗口和样品体密度对相互作用范围影响较大，而探测角对相互作用范围基本没有影响，最后指明了改变分析范围的途径。     

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.     

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.     

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。     

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.     

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.