组合式电磁连铸结晶器内夹杂物运动的数值模拟

采用数值模拟方法对组合式电磁连铸结晶器内夹杂物的运动轨迹和夹杂物在铸坯内的最终分布状态进行了模拟·对静磁场磁感应强度和两种磁场的不同相对位置对夹杂物分布状态的影响进行了分析·分析结果表明:随着静磁场磁感应强度的增强,夹杂去除率提高,皮下夹杂减少,铸坯内的夹杂物分布变得均匀;当静磁场由水口中心逐渐下移时,夹杂去除率降低,皮下夹杂增多,但对内部夹杂物的分布状态影响不明显     

水中空化单泡的磁场效应

基于Navier-Stokes(N-S)方程,推导了稳恒磁场存在时水中空化单气泡的动力学方程,同时数值分析了磁场对气泡运动的影响,并从能量角度讨论了能对水中气泡产生有效抑制作用的磁感应强度范围。结果表明:磁场对气泡振动产生抑制;随着磁场增大,气泡的振动幅度及振动周期减小;磁场能对水中气泡行为产生有效抑制效应的下限应大于0.5T。     

强磁场对镓流体中气泡振动的阻尼效应

基于磁流体动力学,忽略流体磁化效应,建立了有限幅度超声场驱动下均匀磁场环境中气泡的动力学方程,并数值模拟了镓流体中磁场、表面张力、静态压及黏性力对气泡运动的影响,同时基于能量关系分析了磁场对气泡能产生有效抑制作用的理论下限.结果表明:强磁场对气泡振动具有阻尼效应,尤其对气泡的小振幅回弹振动具有强阻尼作用,与表面张力、静态压及黏性力作用相比,磁场作用和黏性力作用类似,可认为,磁场主要通过改变黏性力影响气泡的运动状态;另外,磁场能对镓流体中气泡振动产生有效抑制效应的下限约为0.5T,与数值计算结果一致,即在实验室常用磁感应强度条件下,磁场对气泡振动影响微弱,只有在强磁场(大于0.5T)条件下,对气泡振动的阻尼效应比较明显.     

“磁筛”作用富氧结构磁场优化

对利用"磁筛"作用从空气中富集氧气的永磁体结构进行优化研究.在由两块方形永磁体叠放构成的磁场空间中,中心磁感应强度以及磁场空间对氧气分子的拦截能力随着磁体厚度的增加逐渐提高,但提高速率逐渐减缓,通过增加永磁体厚度增强磁场强度存在一定的饱和度.方形永磁体厚、长尺寸一定时,增加磁体宽度方向的尺寸使磁场空间内的磁感应强度逐渐降低,且在宽度方向上磁场均匀度降低,只有当永磁体厚宽比大于1时,磁场空间内磁场才能满足"磁筛"结构磁场空间内磁场均匀度的要求.永磁体厚度、宽度一定时,磁体长度变化对磁场空间磁感应强度影响较小,可以通过适当增加磁体长度,延长"磁筛"结构对空气的作用时间,增强"磁筛"结构的富氧效果.     

磁共振用Halbach永磁阵列的仿真分析

阐述了Halbach永磁阵列的原理及所产生的静磁场的特点,利用Maxwell仿真软件对一种可用于核磁共振小型化的圆柱型Halbach阵列进行了静磁场仿真分析——首先对理想情况下圆柱型Halbach阵列在不同离散磁块数、磁性材料和磁块尺寸时所产生的磁感应强度进行了对比,然后将充磁方向和磁块性能存在误差的非理想情况与理想情况下的Halbach阵列产生的静磁场进行了对比,最后将Halbach阵列与H型常规永磁体进行了对比.结果表明:组成Halbach阵列的磁块数目、磁性材料的性能和磁块尺寸是影响磁感应强度的主要因素;磁块选材、充磁等加工工艺对Halbach阵列的磁场均匀性有很重要的影响;相比于常规永磁体,Halbach阵列在用料和产生的磁场强度方面具有一定的优势.     

电磁发射制导控制器件强磁场特性分析与离线测试方法

针对电磁发射中脉冲强磁场对制导控制器件的破坏性影响且缺乏重复测试手段的问题,在磁场特性分析的基础上,提出了一种离线测试制导控制器件抗磁场能力的方法。基于电磁发射实际工况,分析给出磁感应强度峰值、磁感应强度变化率和持续时间等综合性能要求;基于系统电路分析、磁场计算建模,提出兼顾磁感应强度峰值和磁感应强度变化率、电源规模以及工作空间的磁场发生装置多目标优化设计方法;并利用有限元仿真对所得设计方案进行验证;最终研制出一套孔径160mm,磁感应强度峰值10.2T、磁感应强度变化率5 487.5T/s并在最大值范围内灵活可调的离线测试装置,实验与仿真结果吻合。该离线测试方法可为电磁发射中制导控制器件在脉冲磁场环境下的保护研究提供灵活高效的测试条件;与原有方式相比,该方法摆脱了发射装置限制,有效降低了成本并提高了测试效率。     

电磁软接触连铸圆坯结晶器磁场分布数值模拟研究(Ⅱ)——结构参数和操作参数的影响

系统地研究了三维圆坯连铸结晶器内磁场分布,分别考察了结晶器切缝长度、切缝宽度、切缝数和结晶器壁厚等结构参数,钢液液面高度、电流强度等操作参数对结晶器内磁场分布的影响.切缝长度从130mm增加到220 mm,磁感应强度最大值从0.056 T增加到0.071 T;切缝宽度从0.3 mm增加到1.1 mm,磁感应强度最大值从0.058 T增加到0.089 T;切缝数从8增加到32,磁感应强度增加明显,32后不再明显;结晶器壁厚从10 mm增加到19 mm,磁感应强度最大值降低近50%;钢液液面应该位于线圈中心位置从而获得最大磁感应强度;磁感应强度最大值随电流强度线性增加.     

超强静磁场对小鼠抗氧化和免疫功能的影响

研究超强静磁场对一周龄小鼠抗氧化和免疫功能的影响.采用磁感应强度为12 T的超强静磁场分别照射小鼠8,12,16 h,照射结束后6,12,24 h,分别取肝脏检测过氧化氢酶（CAT）、谷胱甘肽过氧化物酶（GSH-Px）的活力和丙二醛（MDA）含量,取胸腺和脾脏,测定胸腺、脾脏指数和脾淋巴细胞增殖率.结果表明,超强静磁场可以显著提高小鼠肝脏的CAT和GSH-Px的活力,降低MDA含量,提高机体处理自由基的能力,减少脂质过氧化产物的生成;磁场显著提高小鼠的脾淋巴细胞增殖率,脾脏和胸腺指数也有所升高.试验表明,超强静磁场可以提高机体的抗氧化能力和免疫功能,从而增强机体抗病能力,对延缓衰老有积极作用.     

外加静磁场离心式中间包的流场数值模拟

中间包的流动形态不仅影响钢液成分及温度的均匀,而且也直接影响夹杂物能否漂浮致钢渣层去除。本文以离心式中间包为对象,采用ANSYS CFX研究了均匀静磁场下中间包的流动形态。结果表明:在外加均匀静磁场情况下,中间包内钢液的流动变得更加稳定,有利于对自由液面波动的控制;随着坝高的增加,80%左右区域的自由液面波动会逐渐趋于零,采用较小的磁感应强度更有利于去除夹杂物。     

"静磁场中通过无限大平面的磁通量恒等于零"在特殊对称性磁场中的应用

论述在静磁场中，如何运用“通过任意无限大平面的磁通量恒等于零”的结论，求解某些特殊对称性磁场中的磁感应强度B，为求解静磁场中该类问题提供了一种新的方法．     

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.     

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.     

The Analects and the Moment in Peking——The influence of a Confucian education system on the personality formation,the way of thinking and the fate of the main characters

0.Preface China has long been boasting of its colorful and immense culture which comprises of Taoism,Confucianism and Buddhism.The interwoven influence among the religions on Chinese way of thinking,on the nation＇s behavior in their social life throughout the long history is beyond list.