电窑烧制SiC-Si3N4材料升温过程的数值模拟

用数值仿真的方法模拟SiC-Si3N4材料烧制过程的加热阶段,分析窑内的温度场,发现窑内热棒的位置及供热功率变化对温度分布影响较大.比较了有无对流换热对窑内温度分布的影响,得出对流换热对改善温度场和减小砖坯的表面温差有一定作用;由于发热棒的不合理布置,使得窑内的温度场均匀性较差,升温速率较慢,电窑热效率偏低.     

Power supply for generating frequency-variable resonant magnetic perturbations on the J-TEXT tokamak

To further research the response of the tearing mode(TM) to dynamic resonant magnetic perturbation(DRMP) on the J-TEXT tokamak, a modified series resonant inverter power supply(MSRIPS) with a function of discrete variable frequency is designed for DRMP coils in this study. The MSRIPS is an AC–DC–AC converter, including a phase-controlled rectifier, an LC filter, an insulated gate bipolar transistor(IGBT) full bridge, a matching transformer, three resonant capacitors with different capacitance values, and three corresponding silicon controlled rectifier(SCR) switches. The function of discrete variable frequency is realized by switching over different resonant capacitors with corresponding SCR switches while matching the corresponding driving frequency of the IGBT full bridge. A detailed switching strategy of the SCR switch is put forward to obtain sinusoidal current waveform and realize current waveform smooth transition during frequency conversion. In addition, a resistor and thyristor bleeder is designed to protect the SCR switch from overvoltage. Manufacturing of the MSRIPS is completed, and the MSRIPS equipment can output current with an amplitude of 1.5 kA when its working frequency jumps among different frequencies. Moreover, the current waveform is sinusoidal and can smoothly transition during frequency conversion. Furthermore, the transition time when the current amplitude rises from zero to a steady state is less than 2 ms during frequency conversion. By using the MSRIPS, the expected discrete variable frequency DRMP is generated, and the phenomenon of the TM being locked to the discrete variable frequency DRMP is observed on the J-TEXT tokamak.     

阳极焙烧炉火道数值模拟研究

根据阳极焙烧炉火道内的热工过程,建立了相应的数值仿真模型。运用Fluent软件对焙烧炉火道进行了数值模拟计算,研究了火道内的温度场、流场、浓度场的分布规律。计算结果表明,火道内的挡墙和挡砖对火道内的温度场、流场分布影响很大。     

海南黑山羊瘤胃液中乳酸菌的分离和鉴定

以海南黑山羊瘤胃液为研究对象,对其进行乳酸菌的分离和鉴定,为黑山羊饲料的青贮提供优质的乳酸菌菌株。通过形态学观察及H2O2酶、糖发酵等生理生化试验对所分得菌株进行初步鉴定,并对分离得到的菌株进行16S r DNA基因扩增与测序。结果表明从黑山羊胃液中筛选出15株革兰氏阳性、H2O2酶阴性的乳酸菌疑似菌株,除菌株HBG20不能在p H 3.0条件下生长,其余菌株均能生长;三株代表菌株HBG11、HBG46和HBG86在低温5℃和高温55℃条件以及p H2.5时均能生长,同时在盐浓度为6.5%时也能生长。16S r DNA基因测序结果表明,菌株HBG11与耐久肠球菌(Enterococcus durans)同源性最高,菌株HBG46与植物乳杆菌(Lactobacillus plantarum)同源性最高,菌株HBG86与干酪乳杆菌(Lactobacillus casei)同源性最高。     

多阶梯被动变阻尼装置设计、试验及结构风振控制分析

针对粘滞阻尼器出力范围窄，磁流变等变阻尼装置需能量输入和反馈控制的局限性，在前期单阶梯被动变阻尼装置研制基础上，设计制作了一种多阶梯被动变阻尼耗能装置（Multi-stage Passive Variable Damping Device，MPVDD），该装置采用被动控制方式，在不同速度区间拥有不同的阻尼系数变化规律。对其进行了相关性能验证试验和基于该装置结构风振控制效果的数值计算，试验和分析表明:装置可根据外部激励速度变化，实时机械式改变阻尼系数，实现宽域值变阻尼力的输出，且不需外部能源供给和状态反馈；安装耗能装置高层结构风振下的加速度和位移响应均得到有效控制，保证了风载下结构的舒适性和安全性要求。所做研究为该装置的应用打下了良好的试验和理论基础。     

Numerical simulation of busbar configuration in large aluminum electrolysis cell

Various busbar configurations were built and modeled by the custom code based on the commercial package ANSYS for the 500 kA aluminum electrolysis cell. The configuration parameters, such as side riser entry ratio, number of cathode bars connected to each riser, vertical location of side cathode busbar and short side cathode busbar, distance between rows of cells in potline, the number of neighboring cells, ratio of compensation busbar carried passing under cell and its horizontal location under cell along with large magnetohydrodynamic（MHD） computation based on the custom evaluation function were simulated and discussed. The results show that a cell with riser entry ratio of 11：9：8：9：11 and cathode busbar located at the level of aluminum solution, 50% upstream cathode current passing under cell for magnetic field compensation, the distance between rows of 50 m is more stable.     

对羟基苯海因生产废水的处理

采用盐析／树脂吸附处理对羟基苯海因生产废水。在温度为40℃、芒硝投量为54％、搅拌0．5h至溶解、静置1h后进行油水分层的盐析条件下，对母液挥发酚和COD的去除率分别达到83．40％和87．50％。盐析后母液与洗涤废水按一定比例混合，采用NDA99树脂进行吸附处理，吸附流量为1BV／h，可进一步去除COD和挥发酚，处理效率〉99％，处理床体积为20BV左右。实际工程运行结果表明，采用该技术处理对羟基苯海因生产废水可获得较好的效果。     

铝电解槽内结块物的测试与分析

铝电解过程中产生的结块会在铝电解槽底积聚,影响电解槽中化学反应的平衡,降低工业炼铝的生产效率,加大槽底电压降,加大耗能,磨损电极,影响新添加进铝电解槽的氧化铝的溶解。对氧化铝在电解槽中的溶解和结块行为进行理论分析并采用X射线衍射分析得出了结块混合物中各种的物相和各自所占百分比,结果表明结块物中包含氧化铝和电解质,其中氧化铝占比为39.9%,高于正常指标。使用TEM、SEM对氧化铝、电解质结块进行表面结构分析,得出了结块物由片状物和堆叠而成,堆叠的片物中间有空隙,表面粗糙且不规则。氧化铝厂可以改善原料品质,控制加入原料数量,控制工艺,定期清除电解槽内结块物来达到更高的生产效率。     

古宅深院的江湖菜

<正>醋渍马齿苋把入锅焯过水的马齿苋沥水装盘后,取青二荆条辣椒段和红二荆条辣椒段放上面,另外加入用蒜茸、盐、味精、保宁醋、香油、芝麻等调出来的鲜辣香醋汁,即成。