Effect of slag composition on the cleanliness of 28MnCr5 gear steel in the refining processes

The equilibrium reaction between CaO—Al₂O₃—SiO₂—MgO slag and 28MnCr5 molten steel was calculated to obtain the suitable slag composition which is effective for decreasing the oxygen content in molten steel. The dissolved oxygen content [O] in molten steel under different top slag conditions was calculated using a thermodynamic model and was measured using an electromotive force method in slag–steel equilibrium experiments at 1873 K. The relations among [O], the total oxygen content (T.O), and the composition of the slag were investigated. The experimental results show that both [O] and T.O decrease with decreasing SiO₂ content of the slag and exhibit different trends with the changes in the CaO/Al₂O₃ mass ratio of the slag. Increasing the CaO/Al₂O₃ mass ratio results in a decrease in [O] and an increase in T.O. To ensure that T.O ≤ 20 ppm and [O] ≤ 10 ppm, the SiO₂ content should be controlled to <5wt%, and the CaO/Al₂O₃ mass ratio should be in the range from 1.2 to 1.6.     

一种超弹性SMA复合阻尼器的设计与试验

根据形状记忆合金(SMA)的超弹性特性,设计、制造了一种SMA复合摩擦阻尼器,该阻尼器利用SMA超弹性阻尼与SMA丝的约束作用使阻尼器内部产生摩擦来共同耗散振动能量.介绍了阻尼器的结构构造及工作原理.通过试验研究了加载频率、位移幅值对阻尼器力学性能的影响.试验结果表明,在试验频率范围内,阻尼器的刚度、输出力、耗能等主要力学参数随加载频率的改变而变化较小;位移幅值是影响这些力学参数的主要因素,当阻尼器在小位移的情况下,其刚度变化较小,而输出力和耗能与位移基本成线性关系.但在大位移的情况下,阻尼器的输出力变化较小,而其割线刚度减小,耗能有大幅度的增加.分析表明,该SMA复合阻尼器是一种位移相关性的变刚度阻尼器.     

挛缩膝关节髌韧带应力松弛及蠕变特性的实验研究

探讨兔挛缩膝关节髌韧带的应力松弛和蠕变特性。通过将兔膝关节伸直位制动６周,复制伸直型挛缩膝关节动物模型,然后分别在３７℃、４２℃的条件下,对正常组和制动组髌韧带行应力松弛和蠕变试验。正常组和制动组髌韧带均表现出较明显的应力松弛和蠕变现象;无论是正常组还是制动组,３７℃与４２℃之间髌韧带的最大应力松弛率和最大蠕变率均无显著性差异（Ｐ＞０．０５）,制动组４２℃髌韧带的最大蠕变率较正常组４２℃有显著性增加（Ｐ＜０．０１）。１．髌韧带的这种应力松弛和蠕变特性从机制上解释了牵引、夹板等疗法在挛缩关节康复治疗中的有效性;２．３７℃和４２℃的温差对髌韧带的最大应力松弛率和最大蠕变率均无显著影响     

独塔斜拉桥动力分析

为探讨索面单元法在结构动力分析中应用的可行性,以我国在高烈度区修建的第一座独塔斜拉桥-兰州银滩黄河大桥为工程背景,用索面单元和“脊梁”模型两种不同的有限元模型对进行了动力特性分析;用索面单元对结构体系和震中距的不同对独塔斜拉桥地震反应的影响进行了分析。并探讨了高烈度区独塔斜拉桥地震反应的一些特点。     

Quantale中的L-模糊滤子及其相关性质

基于完备格L,在Quantale中引入了L-模糊滤子的概念,并研究了L-模糊滤子的基本性质.在L是闭集格的条件下,得到了Quantale中的L-模糊滤子的等价刻画;在L是空间式Frame且Q是幂等左半可换Quantale的条件下,证明了LQ上的生成滤子映射是Quantale核映射,进而全体L-模糊滤子构成的Quantale FilL(Q)是LQ的幂等的商Quantale;在Quantale中定义了L-模糊滤子拓扑,并得到了Quantale同态关于相应的L-模糊滤子拓扑连续的结论.     

RNA interference-mediated inhibition of Hepatitis B Virus replication

Persistent and recurrent infection of hepatitis B virus (HBV) represents one of the most common and severe viral infections of humans, and has caused a formidable health problem in the affected countries. Currently used antiviral drugs have a very limited success on controlling HBV replication and infection. RNA interference (RNAi), a process by which double-stranded RNA (dsRNA) directs sequence-specific degradation of target mRNA in mammalian and plant cells, has recently been used to knockdown gene expression in various species. In this study, we sought to determine whether RNAi-mediated silencing of HBV viral gene expression could lead to the effective inhibition of HBV replication. We first developed RNAi vectors that expressed small interfering RNA (siRNA) and targeted the HBV core or surface gene sequence. Our results demonstrated that these specific siRNAs efficiently reduced the levels of corresponding viral RNAs and proteins, and thus suppressed viral replication. Treatment with siRNA gave the greatest reduction in the levels of HBsAg (92%) and in HBeAg (85%) respectively in the cultured cell medium. Our findings further demonstrated that the RNAi-mediated antiviral effect was sequence-specific and dose-dependent. Therefore, our findings strongly suggest that RNAi-mediated silencing of HBV viral genes could effectively inhibit the replication of HBV, hence RNAi-based strategy should be further explored as a more efficacious antiviral therapy of HBV infection.     

地磁感应地电场时频变换快速计算方法

随着中国特高压输电线路的建设,中国电网建设遭受地磁感应电流(geomagnetically induced current, GIC)影响的风险将大大增加。基于大地电阻模型利用有限元计算地磁扰动感应地电场(geomagnetic disturbance, GMD)地电场的方法,建模复杂,利用有限元法计算感应地电场成本过高。地磁测深数据得到的视电阻率综合反映了大地的电性结构,现提出基于视电阻数据及地磁台实测数据直接计算GMD地磁感应地电场的方法。仿真实验表明,该方法可以极大缩短计算时间,减小计算成本,对中国电网应对地磁暴侵害提供了有效算法。计算结果表明地磁暴对各地地电场的影响不均匀,与当地的地质电性结构有很大的关系,同时南北走向的电网将产生更大的GIC,更易受到地磁暴的侵害,应作为主要的关注对象。     

玉米乳的加工工艺优化设计

对玉米乳饮料的工艺流程和方法进行阐述，采用正交试验、线性回归和分析比较法确定了玉米在７０℃下用０．４％Ｎａ２ＣＯ３溶液及液固比为３１的条件下浸泡３５ｍｉｎ，获得了最佳浸泡效果．确定了其它各单元操作的适宜工艺条件，并对玉米乳中的沉淀问题提出了相应的解决方法．     

东海银鲳个体生殖力的研究

本文研究了东海银鲳个体生殖力的分布以及个体生殖力与各体征指标的关系。结果表明：银鲳的个体绝对生殖力ｒ、相对生殖力ｒ／Ｌ（绝对生殖力／体长）、ｒ／ｗ（绝对生殖力／体重）均服从正态分布。个体绝对生殖力ｒ和相对生殖力ｒ／Ｌ与各度量指标均为幂函数关系，与各称量指标则为线性相关，而个体相对生殖力ｒ／ｗ除了与性腺重、成熟系数相关外，与其它体征指标均不相关。本文还进一步给出了个体生殖力ｒ、ｒ／Ｌ、ｒ／ｗ均值的９５％置信区间及个体生殖力ｒ与各指标的多元回纳方程。     

Numerical Simulation of the Morphology and Moving Velocity for Electrospun Stable Jet

GAMBIT,POLYFLOW and FLUENT POST were used to simulate the morphology and the velocity of electrospun stable jet.Simulation results shows that jet diameter decreases with the increased draw force acted on the stable jet.But too great draw force would lead to thick knots appearing along the jet or stable jet disappearing during electrospinning.There is a linear relationship between the velocity and the moving distance.But the linear relationship does not exist under great draw force.