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At present,the rate laws and reaction mechanisms of pyrite oxidation,pyrite and chalcopyrite formation,uraninite and magnetite dissolution in aqueous solutions are mainly studied,and it is discovered that (1)oxidation rate of pyrite controlled by surface reaction assume fractional dependence on Fe3+ and O2 molalities in acid solutions;(2)Pyrite cannot nucleate directly from solutions below 300 ℃,it can only form initially through sulfidation of a FeS precursor. The rate equation of reaction between FeS and H2S to form pyrite is of the second order;(3)Chalcopyrite is formed by reactions of pyrrhotite or pyrite with Cu2+,the former proceeds via a series of mediate metastable phases of Cu-Fe sulfide,whereas the rate equation of the latter is apparently of the first order which is controlled by surface reaction;(4)The nonlinear behavior of magnetite dissolution at acid pH can be represented by a shrinking core model coupling with surface reaction and diffusion transport.

目前主要研究了水溶液中黄铁矿氧化、黄铁矿和黄铜矿形成、晶质铀矿和磁铁矿溶解的速率定律和反应机理，发现：(1)酸性溶液中黄铁矿的氧化速率对Fe3+和O2浓度呈分数依赖并受表面反应的控制；(2)低于300 ℃时黄铁矿不能从溶液中直接成核，而需初始地通过FeS先驱物的硫化生成，FeS与H2S反应形成黄铁矿的速率方程为二级；(3)磁黄铁矿或黄铁矿与Cu2+反应均可形成黄铜矿，前者经历了一系列准稳的Cu-Fe硫化物的中间物，后者的速率方程为表观一级并受表面反应的控制；(4)酸性pH时磁铁矿的非线性溶解行为可采用表面反应扩散输运耦合的收缩核模型来描述。

Gray matter damage was assessed on the basis of the number of normal neurons in the ventral horn. White matter damage was assessed on the basis of the extent of vacuolation and amyloid precursor protein immunoreactivity in the ventral and ventrolateral white matter.

根据腹角内正常神经元的数目评估灰质损伤程度，而白质损伤则根据空泡形成的程度以及腹内和腹外侧白质的淀粉样前质蛋白免疫原性来评估。

In the case of coat color, cells descended from a particular precursor stay together and thus form a patch of the same color, creating the pattern of visible variegation.

甲基化状况可以因两种方式而丧失。甲基可能被一种去甲基酶主动除去，或者甲基化在复制产生的半甲基化位点不能发生。

BALTIMORE, MD -- December 15, 2006 -- A drug commonly used to slow the loss of central ision has shown promise in stemming a common precursor of blindness in diabetics, which inoles the same central light-sensitie area of retina, Johns Hopkins Wilmer Eye Institute scientists report.

马里兰州，巴尔地摩，2006年12月15日讯据约翰霍普金斯Wilmer眼科研究所的科学家报道，一种目前被广泛用来延缓中心视觉丧失的药物有希望用来防治导致糖尿病患者致盲的视网膜早期病变，该病变也发生在视网膜中心的光敏区。

Since the start of the business in 1982, Qingyuan Lianbian Wire Factory of Copper and Aluminum, the precursor of Guangzhou Xinshi Lianbian Electromechanical Device and Equipment Plant which is the most famous glass fiber covered wire manufacturer in south region, now develops to the largest manufacturer in China.

清远市新城联边线材厂前身是广州新市联边机电设备器材厂，是华南地区最著名的玻璃丝包线生产厂。成立于改革开放初期的一九八二年，经过四分一世纪的不断发展、壮大，现已发展为全国产销最大的玻璃丝包线生产厂家。

This yellow fatty streak seen in childhood is not necessarily a precursor of adult atherosclerosis and occurs in populations in which atherosclerosis is uncommon; it is presumably reversible at this stage.

孩童时期便可见到的这种黄色脂纹，并不一定是成年后动脉粥样硬化的先兆，若发生在动脉粥样硬化病不常见的人群中，可能在此阶段是可逆转的病变。

More sinterable yttria powders can be synthesized by calcining the hydroxide precursor with platelet-shaped structure.

添加适量的（NH4）2SO4能够减轻Y2O3粉体的团聚，沉淀的同时控制pH值在9以下，所得到的粉体具有更好的烧结性能。

Porous ceramic was prepared from TZP fine powder which is stabilized by ceria and yttria composite dopant with organic foam as precursor.

以CeO2/Y2O3复合添加剂共稳定的TZP超细粉末为主要原料，用有机泡沫前驱体浸渍法制备多孔陶瓷。

The use of cheap raw materials, simple processes and simple equipment, while in the legal system for a Zirconia-based ceramic materials of valuable hardware, through the precursor decomposition by zirconium oxide ceramic micro base, and on this basis, the use of dry-pressed shaped and without pressure sinter prepared for the implications for sinter explore sintering processes.

本文使用价格低廉的原料、简单的工艺和简易的设备，固相法制备出氧化锆基陶瓷粉体的前驱体，通过前驱体分解得到氧化锆基陶瓷粉体，并在此基础上，利用干压成型和无压烧结对所制备的粉体进行烧结，探讨烧结工艺。

Super-fine K-doped Li2ZrO3 powders were synthesized via the citric acid-ethylene glycol complexing, with the nitrates of lithium, zirconyl and potassium as the materials. Then, the precursor of K-doped Li2ZrO3 and the K-doped Li2ZrO3 powders were characterized by means of TG-DSC, XRD and SEM. Moreover, the thermal decomposition of the gel and the formation of the tetragonal crystalline form were analyzed.

采用柠檬酸－乙二醇络合法，以硝酸锂、硝酸氧锆、硝酸钾为原料制备了掺钾Li2ZrO3超细晶体粉末，采用TG-DSC、XRD、SEM等方法对掺钾Li2ZrO3的前驱体及掺钾Li2ZrO3晶体粉末进行了表征，分析了凝胶的热分解变化过程和四方晶形结构的形成过程。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。