碳酸

Degradation test in vitro was carried out in phosphate buffer solution (0.1M, pH7. 4) at 37 ℃. The buffer solution was changed daily. Degradation test in vivo was implanted the sample to subdermal in adult ICH rat in the scapular area lateral to the dorsal midline. At suitable time the samples were recovered. Molecular weight changes in surface layer and bulk of polymer sample were measured by GPC and weight loss was determined gravimetrically. It was found that the degradation behavior can be regulated by changing the composition of copolymers. The critical compositions from surface to bulk degradation behavior for PGCA, PLCA, PLMCA, PLDCA systems were 15-20, 20-30, 30- 40, 40 of mol percent GA or LA unit in copolymers, respectively. The degradation behavior of PGCA, PLCA, PLMCA, PLDCA systems were compared and analysed. Some factors influencing the degradation character, such as copolymer composition, hydrophobicity, crystallinity and enzyme affect etc. played important role.

体外实验中材料降解环境为37℃，0.1M，pH7.4磷酸缓冲溶液，每天换液，定期取样；体内实验中将聚合物试样埋置于ICH小白鼠背部肩胛骨皮下部位，定期处死小鼠，取样，将体内体外样品进行重量损失及试样内外层分子量变化测定，分析各聚合物试样降解行为特性，实验结果证明，改变共聚物组成，可以调节各聚合体系降解行为特性，对PGCA，PLCA，PLMCA，PLDCA共聚体系，交酯摩尔百分含量15-20％，20-30％，30-40％，40％分别为各体系内降解行为特性由表面降解型向本体降解型过渡的临界转折点，交酯含量较低的聚合物不同程度地表现表面降解行为特性，论文对各共聚体系体内外降解行为作了分析对照，例如共聚物组成对材料降解速度与降解行为的影响；生物体内酶对降解行为的影响；材料亲疏水性，聚合物链段结晶行为及碳酸酯结构对材料降解行为的影响等，得出交酯/环碳酸酯共聚体系降解行为一些共性和规律。

Methods 92 patients with GERD were randomly divided into the treated group with Danzhi Xiaoyao pill and hydrotalcite and the control group with hydrotalcite only.

方法92例胃食管反流病患者随机分为丹栀逍遥丸联合铝碳酸镁治疗组(46例)及铝碳酸镁对照组(46例)。

Using manganous sulfate(MnSO4) as raw material,ammonium hydrogen carbonate(NH4HCO3) as precipitating agent and sodium dodecyl sulfate as particle size controller and through the process of quick addition of MnSO4 and NH4HCO3 solutions at same time,monodisperse submicron manganous carbonate(MnCO3) spherical particles were prepared by controlling suitable reaction crystallization conditions.

以硫酸锰为锰源，碳酸氢铵为沉淀剂，十二烷基硫酸钠为粒径控制剂，采用硫酸锰和碳酸氢铵两种溶液快速同时加入的方式，通过控制合适的反应结晶条件，制备出亚微米级单分散球形碳酸锰颗粒。借助扫描电镜、X射线衍射、粒度分析仪等研究了反应结晶条件对碳酸锰粒径和形貌的影响。

By combining resolution and protection of DBSPINOL with menthyl chloroformate, the enantiopure SPINOL and other 4,4'-derivatives have been synthesized effectively via (1S)--4,4'-dibromo-l,r-spirobiindane-7,7'-diyl bis-menthyl carbonate with n-BuLi following reacting with electrophiles of I2, MeI, CO2 and water.

在制备其它衍生物反应中，薄荷醇碳酸酯成为羟基的保护基，DBSPINOL碳酸酯用正丁基锂处理后，再和亲电试剂作用合成了其它4，4'位二碘代、二甲基取代和二羧基取代SPINOL新化合物。

ABSTRACT Purpose By adding additives in carbonated hydroxyapatite cement to increase its rheology to prepare injectable carbonated hydroxyapatite cement.(1) Test the physicochemistry characteristics of ICHA cement.(2) Evaluate the biocompatibility of ICHA cement.(3) Biomechanieal appreciation of ICHA cement used in distal radius fracture.(4) Study the mechanical stability, degradation and bone formation ability of ICHA cement used in goat lateral tibial plateau compression fracture.

目的 在碳酸化羟基磷灰石(Carbonated hydroxyapatite，CHA)水泥原位固化基础上进行改性研究，通过改变其流变学特性，达到具有良好注射性能的可注射性碳酸化羟基磷灰石(Injectable carbonated hydroxyapatite，ICHA)水泥，为骨科的微创治疗提供新方法：(1)制备ICHA水泥，完成理化性质的检测；(2)进行ICHA水泥的生物相容性评价；(3)探讨ICHA水泥在桡骨远端骨折应用的生物力学固定强度；(4)研究ICHA水泥在实验性大动物胫骨平台压缩性骨折中应用的力学稳定性、降解性能及成骨性能。

And a novel synthesis process of dimethyl carbonate from urea and methanol was proposed. Polyphosphoric acid is used as the catalyst and the coupling reagent in the process.

应用共生耦合理论对尿素醇解法制备碳酸二甲酯的合成反应体系进行了分析，提出了一种由尿素和甲醇制备碳酸二甲酯的新工艺。

The source,existing form and equilibrium of carbonic acid in natural water are presented in this article,which points out that alkalinity is determined by double indicator that indicates purply at the first terminal point,while at the second terminal point should use methyl red-bromocresol green mixed indicator.

介绍了天然水体中碳酸的来源、存在形式及平衡关系；指出用&双指示剂&法测定水中碱度的第一终点应显粉紫色，第二终点宜采用甲基红-溴甲酚绿混合指示剂；测定游离二氧化碳要用双样测定并严格控制滴定终点；各种碳酸的含量可与pH值、硬度的测定结果进行校核。

Experimental study on effect of acetic acid and carbonic acid on clay's geotechnical behaviors;2. The source,existing form and equilibrium of carbonic acid in natural water are presented in this article,which points out that alkalinity is determined by double indicator that indicates purply at the first terminal point,while at the second terminal point should use methyl red-bromocresol green mixed indicator.

介绍了天然水体中碳酸的来源、存在形式及平衡关系；指出用&双指示剂&法测定水中碱度的第一终点应显粉紫色，第二终点宜采用甲基红-溴甲酚绿混合指示剂；测定游离二氧化碳要用双样测定并严格控制滴定终点；各种碳酸的含量可与pH值、硬度的测定结果进行校核。

Currently, with its mature condition and complete infrastructure, more than 10 enterprises have entered the town, including China Science Research Institute Guangzhou Chemical Research Institute. A newly-risen industry products group has been formed, including vinyl esters, dimethyl ester, saleratus, degradable polyurethane foam etc.

目前开发利用条件成熟、设施完备，中科院广州化学研究所及10多家生产企业在镇内落户，已初步形成碳酸乙烯酯、丙烯酯、二甲酯以及小苏打、脂肪族聚碳酸亚乙酯、降解型聚氨酯泡沫塑料等新兴产业产品群。

Accordingly a further feature of the invention is a combined process wherein a dialkyl phenylethylmalonate is made from an alkyl phenylacetate and a dialkyl carbonate by a process comprising adding to a quantity of sodium which is covered with a hydrocarbon solvent boiling above 100°C, at least a chemically equivalent proportion of a lower aliphatic alcohol, subsequently adding an approximately equivalent proportion of a dialkyl carbonate and of an alkyl phenylacetate, heating the mixture to induce reaction and continuously distilling out the alcohol formed from the reaction zone and finally causing the sodio diethyl phenylmalonate so obtained to interact with an ethylating agent, such as ethyl halide, diethyl sulphate of ethyl p-toluene-sulphonate.

因此，本发明的另一个应用是一个组合工艺过程：二烷基苯基乙基丙二酸酯由烷基乙酸苯酯和二烷基碳酸酯得到，具体工艺过程是：向覆盖有沸点超过一百摄氏度的团庆化合物溶剂的金属钠中添加至少化学平衡的低级脂肪族醇，然后加入大约相同当量的二烷基碳酸酯和烷基乙酸苯酯，加热混合物引导反应进行，持续蒸馏把形成的醇类从反应区域移出，最后使获得的二乙基苯基丙二酸酯和乙基化试剂如卤代乙烷，二乙基硫酸酯形成乙基p-甲苯磺酸酯。

They weren't aggressive, but I yelled and threw a rock in their direction to get them off the trail and away from me, just in case.

他们没有侵略性，但我大喊，并在他们的方向扔石头让他们过的线索，远离我，以防万一。

In slot 2 in your bag put wrapping paper, quantity does not matter in this case.

在你的书包里槽2把包装纸、数量无关紧要。