Interaction of Impurity (Li, Be, B and C) and Hydrogen Isotope Pellet Injection with Reactor-relevant Plasmas

Based on the two-dimensional kinetic ablation theory of the hydrogen pellet ablation developed by Kuteev [B.V. Kuteev, Nuclear Fusion, 35 (1995) 431], an algorithm of erosion speed and ablation rate calculations for Li, Be, and B impurity pellets in reactor-relevant plasma has been derived. Results show compatibilities of lithium pellet injection used in α-particle diagnostics are positive in comparison with other solid impurity pellets (e.g. Be, B and C). Using the 2-D Kuteev lentil model, including kinetic effects, we find that currently existing pellet injection techniques will not meet core-fueling requirements for ITER-FEAT. A pressure as high as 254 MPa must be applied to a pellet accelerator with a 200 cm-long single-stage pneumatic gun, in order to accelerate a pellet with a radius rpo = 0.5 cm to a velocity of vpo, 24 × 105 cm/s penetrating 100 cm into the ITER plasma core. Comparisons of pellet velocity- and radius-dependent penetration depth between the Neutral Gas Shielding and the Kuteev's models are made. However, we find that the isotopic effects can lead to a 33% lower pellet speed for solid DT, compared to an identical H2 pellet penetrating the same length in ITER-FEAT plasma, and our calculations show that HFS injection will much improve core fueling efficiency.

Fuelling and Diagnostics with Pellet Injection in the HL-1M Tokamak

The pellet injection experiments for fuelling and diagnostics have been carried out on the HL-1M tokamak. The eight-pellet injector was installed on HL-1M. A reliable monitordetector and camera system was set up to take initial pellet photographs and measure the initial pellet speed and size. High fuelling efficiency of 60 % - 100 % and a density profile with a peaking factor of 1.8 - 2.0 were obtained. The maximum density close to 10^14/cm^3 in HL-1M was achieved with newly optimized combined fuelling techniques. Two typical models of pellet ablation have been utilized for simulative calculation of the ablation rates in HL-1M. In comparison with the distribution of the measured Hα emission intensity from the digital data of the CCD camera, the experimental result seems more optimistic for core fuelling than theoretical predictions by the two models. The safety factor profile q（r） has been extracted from the information provided by the CCD camera during the pellet injection. The reliability of the measured results depends mainly on the calibration of the imaging space position. Based on the calibration, the measured q-profile becomes more reasonable than those published previously for the same shot number and same photograph.

预热竖窑气固传热与水分蒸发数值模拟

通过对一种新型预热竖窑的预热脱水研究,建立了气固两相传热和水分蒸发收缩核模型.在气体速度分别为10,15和20 m/s与993 K的温度条件下,针对预热竖窑的气体温度分布,以铬铁球团为主的固体混合物料温度分布和水分蒸发情况进行模拟分析.结果表明,该预热竖窑在20 m/s与993 K的条件下,固体物料温度达到850 K以上并实现球团干燥,可以满足物料预热的温度和含水量要求.通过合理的预热工序,防止了冶炼过程中因含水率过高导致球团出现爆裂影响生产安全的问题,也满足了企业对冶炼过程中产生的高温尾气的余热利用的目标.

针刺对NIDDM大鼠作用的形态学观察

目的 :探讨针刺对非胰岛素依赖型糖尿病 (NIDDM)大鼠胰岛素B细胞形态的影响。方法 :采用生化、放免等技术观察针刺对NIDDM大鼠空腹血糖 (FBS)、空腹胰岛素 (FINS)、C -肽 (C -P)、胰岛素敏感性指数 (IAI)的变化 ,同时用电子显微镜观察针刺对NIDDM大鼠胰岛B细胞形态学的改变。结果 :NIDDM大鼠B细胞体积增大 ,内分泌颗粒增多 ,苍白颗粒减少 ,芯颗粒与分泌颗粒的面积之比也明显增多 ,可见胰岛外分泌细胞可化生B细胞。针刺治疗后NIDDM大鼠FBS ,FINS ,C -P均显著下降 ,而IAI显著回升。与此同时 ,上述形态学的异常均出现逆转。结论

离心造粒法制备微晶纤维素空白丸核的工艺研究

目的研制一种无糖型空白丸核为药物粉末层积提供便捷、优质的母核。方法用国产实验室规模的离心包衣造粒机研究了制备微晶纤维素空白丸核的工艺。以产率、粒径分布、堆密度、粒密度、表面形态和圆整度及脆碎度为评价指标 ,用完全析因设计实验讨论了重要工艺参数主机转速、鼓风流量对空白丸核物理性质的影响。结果和结论主机转数对丸核产率、粒径分布有显著影响 ;鼓风流量则影响丸核的表面形态、圆整度和堆密度 ;

单颗粒结焦催化剂再生过程粒内温度

考察了球形单颗粒结焦催化剂粒内温度随再生时间的变化，并提出了颗粒直径上各点在再生过程中的温升均有最大值，且离球心越近，最大温升越大，以及最大温升出现的时间越晚，其再生过程呈现未反应蕊缩蕊模型的特征。

生物矿石颗粒浸矿方法研究

真菌具有生长速率快、生物量大、适应性强、发酵产生有机酸等特点,可应用于低品位矿石及尾矿中有价金属的提取.根据真菌浸矿过程中,真菌菌丝可以包裹矿石形成多个以矿石颗粒为内核,真菌菌丝为外壳的核-壳结构的生物矿石颗粒的特征,提出了生物矿石颗粒浸矿新方法.介绍了生物矿石颗粒浸矿方法的原理,及其在铜尾砂和铀矿石浸出中的应用.

稳定的新型雷贝拉唑钠肠溶微丸

目的制备在肠道内更稳定的可释放两次的雷贝拉唑钠。方法用挤出滚圆法制备雷贝拉唑钠载药微丸丸芯并优化其处方及工艺。载药丸芯包裹隔离层后分别包裹两种肠溶层,制成雷贝拉唑钠肠溶微丸,混合后对释放度和稳定性进行测定。结果载药丸芯处方为10%无水碳酸钠,10%甘露醇,20%雷贝拉唑钠,20%低取代羟丙基纤维素,40%微晶纤维素,以5%羟丙基甲基纤维素的水-乙醇(65:35,W/W)溶液为黏合剂。以欧巴代胃溶型包衣液为隔离层,增重8%,欧巴代肠溶型94系列和尤特奇S100包衣材料为肠溶层,增重15%和20%,得到的微丸含量为97%。混合微丸在p H6.8的磷酸盐缓冲液中60min释放度为40%,120min释放度为70%,在p H8.0的三羟甲基氨基甲烷缓冲液中60min释放度大于80%,且较为稳定。结论成功制备了雷贝拉唑钠肠溶微丸,可在更稳定的p H环境下释放,并具有潜在的两次释放的特征。

中心复合设计法优化微晶纤维素空白母核的制备工艺

目的优化制备微晶纤维素(microcrystalline cellulose,MCC)空白母核的工艺条件。方法采用实验室规模的离心造粒机制备MCC空白母核,以产率(Y1)为主要评价指标,应用中心复合设计法优化制备工艺。结果鼓风流量(X1)对评价指标有非常显著影响(P<0.01),主机离心速度(X2)对评价指标有显著影响(P<0.05),拟合所得多元二次方程为Y1=72.7+5.004 X1-4.2925 X2-3.25 X12-4.2 X22,相关系数为0.912 0。在优化区域内选择一点安排1次验证试验,以检验优化工艺条件的有效性。验证试验表明,本优化方程有良好的预测性。结论中心复合设计法优化的制备条件良好,制得的MCC空白母核符合要求。

核壳结构Fricke凝胶剂量计小球的制备及扩散限制的研究

设计制备了一种具有物理扩散限制层结构的核壳结构小球,将存在扩散的Fricke凝胶剂量计包裹在聚二甲基硅氧烷壳层内,最大限度解决Fe3+的扩散问题。制备过程简单,利用双微流控通道制备核壳小球,实验可重复性好,制备的小球大小形貌良好,小球平均直径约为2.90 mm,壁厚为0.22 mm,有限元模拟结果研究表明此核壳结构可应用于剂量验证。

转底炉内冶金粉尘还原过程数值模拟

基于计算流体力学方法并以收缩核模型为基础建立了转底炉内燃烧、烟气流动、气体与冶金粉尘球团传热传质及冶金粉尘球团化学反应的全耦合数学模型,计算了中径36 m的转底炉内流场、温度场及冶金粉尘球团内铁氧化物的还原反应,重点分析了球团内部各种铁氧化物浓度及球团的金属化率.采用文献中球团在高温硅钼炉内进行的还原实验验证了模型的可靠性.结果表明,在本文工况下,经过一个工作周期(25 min),炉膛内烟气流速随流动方向逐渐增大,转底炉中径处球团温度为1416.7 K,铁的浓度由3477.50 mol/m^(3)增长至9719.94 mol/m^(3),冶金粉尘球团的金属化率最高可达90.85%,平均金属化率为81.42%.

Fabrication of Thorium and Thorium Dioxide

Thorium based nuclear fuel is of immense interest to India by virtue of the abundance of Thorium and relative shortage of Uranium. Thorium metal tubes were being cold drawn using copper as cladding to prevent die seizure. After cold drawing, the copper was removed by dissolution in nitric acid. Thorium does not dissolve being passivated by nitric acid. Initially the copper cladding was carried out by inserting copper tubes inside and outside the thorium metal tube. In an innovative development, the mechanical cladding with copper was replaced by electroplated copper with a remarkable improvement in thorium tube acceptance rates. Oxalate derived thoria powder was found to require lower compaction pressures compared to ammonium diuranate derived urania powders to attain the same green compact density. However, the green pellets of thoria were fragile and chipped during handling. The strength improved after introducing a ball milling step before compaction and maintaining the green density above the specified value. Alternatively, binders were used later for greater handling strength. Magnesia was conventionally being used as dopant to enhance the sinterability of thoria. The normal sintering temperature for magnesia doped thoria was 1600℃ - 1700℃, which was achieved in electrically heated molybdenum element sintering furnaces with reducing atmosphere. 0.25 mole percent addition of niobia to the thoria was found to bring down the sintering temperature to 1150℃. Sintering could be done in ordinary furnaces in air atmosphere using silicon carbide or Kanthal heating elements. Electrical conductivity was measured for both magnesia and niobia doped sintered thoria and used in interpreting differences in sintering behavior.

钢带烧结料层的干燥氧化过程仿真

针对钢带烧结机内铬铁球团的干燥氧化过程,建立一套多尺度的欧拉-欧拉双流体数学模型.基于收缩核模型计算单个球团的物理化学反应,模型预测结果与现场数据吻合.结果发现生球层的干燥可以分为两阶段:不均匀升速干燥阶段和降速干燥阶段.在生球层底部,第二干燥阶段会出现干燥速率又升高的现象,此时湿核表面温度为383 K.而当湿核半径小于4.75 mm后干燥速率又开始下降.过湿区的最大水分质量分数为10.2%,比初始值高7.4%.当铬铁球团的温度达到焦炭的燃点后,焦炭的氧化优先于磁铁矿.生球层在烧结区出口的平均温度达到1698 K,满足生产需求.

含铁黏结剂对磁铁矿球团氧化动力学的影响

通过改变磁铁矿球团中含铁黏结剂的配比(0%、4%和8%),进行了球团氧化的动力学研究。首先利用TG-DTG-DSC分析确定了磁铁矿粉氧化的温度范围为240.1~1029.7℃,其后在温度400~1000℃和时间0~15 min内对球团进行了等温氧化动力学试验。根据反应过程中球团FeO含量随氧化时间的变化数据,分析了球团氧化度的变化规律以及含铁黏结剂对球团氧化度的影响。分别采用0级、1级和2级基元反应级数的f(C)-t图(C为质量分数,t为时间)对试验数据进行了拟合。结果表明,球团氧化反应符合1级反应的动力学规律,并确定了不同含铁黏结剂配比条件下反应的速率常数k。最后根据未反应核收缩模型和Arrhenius方程计算了反应的活化能,并判断了反应的限制性环节。研究显示,在低温段(400~700℃),含铁黏结剂配比为0%、4%和8%时,氧化反应的活化能依次为23.40、20.83、20.73 kJ/mol,表明含铁黏结剂可以加速球团的氧化进程,原因在于黏结剂结晶水的析出增加了球团内部的孔隙率,使气体O_(2)与磁铁矿的接触更加充分,球团氧化速率更快;但含铁黏结剂配比由4%增加到8%时,球团氧化速率增加幅度较小,原因在于黏结剂中结晶水的分解和扩散影响了球团的氧化。在高温段(800~1000℃),不同含铁黏结剂的反应活化能依次为43.37、35.16、35.98 kJ/mol,呈先降后升的趋势,表明过量的含铁黏结剂反而不利于氧化反应的进行。研究结果对优化含铁黏结剂配比、改善球团矿质量和指导球团矿生产具有重要意义。

High-Temperature Oxidation Behavior of Vanadium,Titanium-Bearing Magnetite Pellet

By means of isothermal oxidation and chemical analysis, great importance was attached to the parameters that made effects on the oxidation degree of vanadium, titanium-bearing magnetite pellet in high-temperature processing （1 073- 1 323 K）. Based on the experimental data, oxidation kinetics of pellet was analyzed according to shrinking unreacted-core model subsequently. Experiment results display that the oxidation degree of pellet increases with increasing of oxidation time, oxidation temperature and oxygen content, as well as shrinking of pellet diameter. Under the condition of oxidation time 20 min, oxidation temperature 1223 K, oxygen content 15%, and pellet diameter 12 mm, oxidation degree of pellet reaches 92.92%. The analysis of oxidation kinetics indicates that oxidation process of pellet is controlled by chemical reaction with activation energy 68.64 kJ/mol at a relatively lower temperature （1073-1 173 K）. Oxidation process of pellet is mixed-controlled by chemistry reaction and diffusion with activation energy 39.66 kJ/mol in the temperature range of 1 173-1 273 K. When oxidation temperature is higher than 1 273 K, the limited link of oxidation reaction is the diffusion control with the activation energy 20.85 kJ/mol. These results can serve as a reference to the production of vanadium, titanium-hearing magnetite pellet.

Effect of MgO on Oxidation Process of Fe_3O_4 in Pellets

Induration process of oxidized pellets involves the oxidation of Fe3O4 and re-crystallization of Fe2O3.The oxidation process of Fe3O4 is significant for pellets to obtain better ambient strength.Thus,the effect of MgO on oxidation process of Fe3O4 was investigated.The unreacted core model was applied to analyze the oxidizing induration process of pellets.The experimental results show that MgO plays a negative role in the oxidation process of Fe3O4.The oxidation rate of Fe3O4 in MgO-fluxed pellets（95.0% Fe3O4 ＋5.0% MgO）is slower than that in standard acid pellets（100% Fe3O4）.The relation between oxidation ratio of Fe3O4 and time was calculated based on the unreacted core model for both MgO-fluxed pellets and standard acid pellets.According to verification experiments,the values calculated by model coincide well with the experimental values.Therefore,the unreacted core model could be applied to describe the oxidizing induration process of pellets.

Theoretical Foundation of Carbonation Pellet Process for Ferrous Sludge Recycling

For the recycling of ferrous sludge from steel industry,the carbonation pellet process should be considered as a ＂green＂ process,since no impurities are added as well as CO2 can be sequestrated and consumed.Through the thermodynamic calculation,the carbonation reaction can occur spontaneously and is an exothermic reaction.Based on the kinetic analysis through unreacted core model,the interfacial chemical reaction was the rate controlling step in the initial fast stage of carbonation,and the CO2 diffusion through the CaCO3 product layer was the rate controlling step in the following extremely slow stage.For the carbonation bonded mechanism,the pellet strength was gained by the formation and growing of CaCO3 product layer.Since the interfacial chemical reaction was the critical stage of the entire carbonation process,the emphasizes should be focused on the improvement of sorbent activity and the optimization of process parameters,such as pore structure,pore surface area,and total pressure,CO2 partial pressure,reaction temperature,etc to accelerate the reaction rate and to improve the quality of carbonation pellets.

武钢球团矿还原反应动力学

采用热失重法在900～1100℃的范围和CO的体积分数为100％的气氛条件下，对武钢球团矿进行恒温还原实验，通过阿伦尼乌斯（Arrhenius）图和未反应核模型公式分别计算了还原反应的表观活化能和反应速率常数、扩散系数，并判断反应速度的限制性环节，使用场发射扫描电子显微镜（FESEM）和能谱分析（EDS）观察了球团矿在还原过程不同阶段的微观形貌和铁的氧化物的形式，分析了球团矿的反应机理。结果表明：在球团矿还原反应前期至中后期的大部分时问内，反应的限制性环节为界面化学反应，而后期限制性环节改变为固相扩散；球团矿还原是按照铁的氧化物从高级到低级的顺序进行的，采用未反应核模型进行动力学分析是正确的。

4种辅料空白丸芯制备工艺的优选及差异性分析

目的:优选不同辅料空白丸芯的制备工艺,探索微丸母核制备工艺和制剂原料之间的适宜性。方法:采用离心造粒法分别制备微晶纤维素、淀粉、糊精和乳糖4种辅料空白丸芯,以粒径分布在0.25～0.355 mm的丸芯得率为主要评价指标,采用单因素试验、均匀设计试验和多元线性回归统计法优化4种辅料空白丸芯的制备工艺,并分析其差异性。结果:适宜4种辅料丸芯制备的工艺参数为微晶纤维素以水为黏合剂,其他3种辅料均以50%～60%蔗糖溶液为黏合剂,喷浆速度12～16 r.min-1,微晶纤维素、糊精和乳糖起母的主机转速225 r.min-1,淀粉起母的主机转速275 r.min-1,喷气压力0.025～0.05MPa,温度25℃,鼓风流量选小或中。结论:制备的4种不同辅料空白丸芯存在普遍适宜的工艺参数范围,研究为离心造粒法制备含药微丸的处方筛选和工艺参数优化提供参考。

琥珀酸美托洛尔微丸型缓释包衣片的制备及其在Beagle犬体内的药动学

以粒度分布、圆整度和包衣增重为评价指标,分别采用Box-Behnken设计-响应面法和单因素法优化琥珀酸美托洛尔微丸型缓释包衣片的丸芯制备工艺与缓释层包衣工艺。优化工艺制备的含药丸芯粒度分布均匀、圆整性好,包衣后微丸增重稳定、粒度分布均匀。微丸压片前后在水中的释放曲线无显著性差异。3批自制缓释包衣片在4种pH值介质中的释放曲线与原研制剂(倍他乐克)相似,表明本工艺重现性良好。以Beagle犬为模型,采用双周期交叉试验设计,考察了空腹和进食状态下自制制剂与原研制剂的体内药动学行为,并进一步评价了体内外相关性和生物等效性。结果显示,空腹和进食状态下自制制剂均具有良好的体内外相关性,并与参比制剂生物等效。