酸值

In this paper, a moving-boundary problem occurring under the acidifying was discussed, which was transformed into a coupled problem of an initial-boundary value problem of nonlinear parabolic equation and an initial value problem of differential equation.

建立了油气层酸化过程中的动边界模型，经Landau变换后，将所求问题转化为定边界上的非线性抛物型方程初边值问题和常微方程的初值问题的耦合问题，并给出了耦合问题的全离散格式。

Acid rain has a pH of 2or less and is responsible for acidifying streams and lakes and ,thus,not only killing fish but leaving the waterway too acidic to be reinhabited.

2酸雨的pH值为2甚至更小，它能使河流湖泊酸化，因此不但会导致鱼类死亡，还会令水流经之处的土壤酸性过强而无法生长植被。

At the same time, the fouling mechanism of membranes given in this thesis can give a reasonable explanation on the change of membrane performance. Our results show that the magnetization of membranes can effectively improve the anti-fouling ability of the PAN- Fe_3O_4 membrane. The obtained result may give insight to the development of new membranes with a good anti-fouling performance in the filtration of blood solution. No chemical bond was found between PAN and Fe_3O_4 in the membrane at room temperature. The addition of Fe_3O_4 can improve the temperatures of dehydrogenated reaction and decomposition of PAN but dot change the glassy transition temperature. The resistance against acid is stronger than the resistance to base for a PAN- Fe_3O_4 membrane.

结果表明在PAN- Fe_3O_4超滤膜制备过程中使用外加磁场作用能有效提高膜的耐污染能力，这一结果为开发适用于血液处理的耐污染超滤膜提供了一种新途径；在PAN- Fe_3O_4超滤膜中，四氧化三铁与PAN在室温下没有形成化学键，也不存在官能团之间的相互作用；添加Fe_3O_4对膜的玻璃化温度没有影响，但能提高PAN环化脱氢反应的温度和分解温度；PAN- Fe_3O_4超滤膜的耐酸性强于耐碱性，在pH值为10以上的溶液中由于水解作用而溶解，使得膜失去使用价值，膜的耐酸性与酸的种类、浓度和氧化性有关。

Compounds 3a-3d, 4a-4d, 5a-5d, 6a-6e and 7a-7e were prepared with a new efficient method, in which the aromatic amines were diazotized with isoamyl nitrite in EtONa/EtOH under refluxing condition, and mono -, bis -and tetrakis -substituted calix [4] arenes were obtained respectively as main product by diazo-coupling in different molar ratio to calix [4] arene.

一，提出了一个有效的新方法合成含有芳香偶氮基团的杯[4]芳烃衍生物3a-3d；4a-4d；5a-5d；6a-6e和7a-7e：即在非水溶剂乙醇中用亚硝酸异戊酯，在强碱乙醇钠存在下对芳香胺进行重氮化，得到芳香重氮酸盐沉淀，过滤，然后加入杯[4]芳烃的四氢呋喃溶液，通入CO〓气体调节溶液的pH值为7-9，使其发生偶联反应。

The HPLC method has been used to investigate the stability of etimicin in 0.9% sodium chloride, 5% glucose, 10% glucose, compound sodium chloride, glucose sodium chloride and so on. In the experiment, the ODS-C18 column (4.6mm×250mm), mobile phase: methanol/water/acetic acid=80/16/4 (containing heptane sulfonic sodium 0.02mol/L), UV detection with wavelength of 330nm were employed. After integrating each of the menstruums with etimicin, the content and pH value were measured after 1h, 2h, 4h, 6h and 8h at a temperature of 17, 25 and 35℃, respectively.

实验采用HPLC法，以C18柱为色谱柱，CH3OH：H2O：HAc=80：16：4（含0.02mol/L庚烷磺酸钠）为流动相，检测波长330nm；对依替米星在生理盐水，5%葡萄糖，10%葡萄糖，复方氯化钠，葡萄糖氯化钠等溶媒中进行了稳定性研究，在室温(17℃)，25℃，35℃情况下，将依替米星与不同的溶媒配伍后，在1h，2h，4h，6h，8h分别测定它们的含量及pH值。

The octahedrons, spheres, rods and hollow spheres of K_2HOF_4 were obtained by controlling the experimental parameters.

通过实验还研究了体系的酸、碱性对物相形成的影响，适宜的pH值大约是7-8。

The measurement of acid dispersion index indicates that the pseudo-boehmite powder canbe peptized completely. When n_H+/n_AlOOH·nH2O =0.097, the corresponding pH value is 3.4. The calculated potential barrier is 6.31 ×10~-18J according to DLVO model. The size of the colloidal particulates is around 5-10nm, being cross-link as is shown by TEM.

酸分散指数的测定表明当n_/n_(AlOOH·nH_2O)=0.097时，拟薄水铝石可以完全胶溶，稳定水溶胶的pH值为3.4；根据DLVO模型计算的位能势垒为6.31×10~(-18)J；TEM观察溶胶的胶粒为5-10nm，且部分粒子相互网联。

Pseudo-boehmite was prepared with nitric acid and sodium aluminate under the same precipitation conditions but different ageing and washing conditions. The influences of ageing temperature, ageing time and ageing media were studied. It was shown that pronging the ageing time and increasing temperature lead to improve crystallinity of PB., the pore diameter of PB can be increased after NH4HCO3 is added in the ageing medium.

在相同成胶条件下利用铝酸钠溶液和硝酸制备拟薄水铝石，而在不同条件下进行老化，研究了老化温度、老化时间及老化介质的影响，结果表明延长老化时间、提高老化温度和老化pH值有助于结晶度的提高，使用NH4HCO3等具有扩孔作用的溶液作为老化介质会降低产品的堆密度和增加孔径、孔容、比表面积。

It was found that the content of γ-amino butyric acid in brown rice reached the maximum value after soaking for 4 hours at the ratio of brown rice and sodium glutamate 1 200 g/mol, and under the soaking!conditions of pH 5~6, Ca~ 2+ Conceutritio...

发现糙米在浸泡温度40~50℃，Ca2+浓度为0.5mmol/L，pH值为5~6，糙米与谷氨酸钠的比值为1200g/mol的浸泡液中浸泡4h后，其γ-氨基丁酸含量分别达最高。

Results］ The optimal process condition of the hydrolysis of phytic acid was:the temperature, 37 ℃; the pH value, 5.0; the substrate concentration, 10% and the best reaction time, 16 hours.

结果］水解植酸的最佳工艺条件是：温度为37 ℃、pH值为5.0、底物浓度为10%、反应时间为16 h。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。