化

Three methodsconventional direct acylation,acylation by phase transfer catalyst(PTC,and ionexchange-acylation were selected for the purpose of acetylating κ-carrageenan with 30kDa molecular weight.

选择常规直接酰化、相转移催化酰化和离子交换-酰化共3种方法对3万中等分子量的κ-卡拉胶进行了乙酰化反应。

"Acetylating H3K4 and demethylating H3K9 can actiate a gene; deacetylating H3K4 and methylating H3K9 can silence it," Karpen explains."Multiply modified at arious locations, these histones are a major factor in changing the functions of chromatin, independent of DNA sequence."

&H3K4的乙酰化和H3K9的去甲基化使基因活化；而H3K4去乙酰化和H3K9的甲基化则使基因沉默，& Karpen讲解道，&组蛋白的多部位多重调节是改变染色质功能的主要因素，并与DNA的序列无关&

Methods After treated with a specific demethylating agent,Aza and acetylating agent, TSA, the status of 5'CpC island methylation of ING1b gene in HT29 human colon cancer cell line was analyzed using methylation specific polymerase chain reaction,and the level of histone acetylation was analyzed by chromatin immunoprecipitation,and reverse transcription polymerase chain reactionwas used to examine ING1b mRNA expression.

应用特异性DNA甲基转移酶抑制剂5-氮-2'-脱氧胞苷（5-Aza-2'-dc，以下简称Aza）及组蛋白去乙酰化酶抑制剂曲古抑菌素A作用人结肠癌细胞株HT29后，用甲基化特异性PCR检测该ING1b基因核心启动子区域CpG岛甲基化情况，用染色质免疫沉淀检测其乙酰化组蛋白绑定的DNA情况，并用逆转录聚合酶链反应检测ING1bmRNA表达。

Introduce of actual acidification velocity(H~+ produced) for evaluating the acidifying effects of soil tested,only the stimulated acid rain with pH2.5 could lead to soil acidifying,however,acid rains with pH≥3.5 played a buffering role to soils tested,with the weakening of soil acidity.

引进土壤的实际酸化速率H产生+值衡量供试土壤的酸化，只有pH2.5的模拟酸雨淋溶促进了土壤的酸化，而pH≥3.5的模拟酸雨处理对土壤的酸化具有一定的缓冲作用，且土壤酸度减弱。

The fluidization characteristics of ultrafine particles are reviewed and the agglomerating process is analyzed.

首先阐述了超细颗粒的流化特性(初始流化速度、床膨胀等)及团聚流化过程，然后重点对近年来国内外在改善粘性颗粒流化质量方面所作的研究工作进行了总结。

A one-step method for the synthesis of aromatic indolizine derivatives byintramolecular 1,5-dipolar cyclization reaction of 2-(2-arylethenyl)pyridinium N-ylidesin the presence of an oxidant has been studied for the first time. In the presence ofelectron-deficient olefins, however, 2-(2-phenylethenyl)pyridinium N-ylides underwent1,3-dipolar cycloadditions and then aromatized in situ by TPCD to produce indolizinederivatives, indicating 1,3-dipolar cycloaddition proceed more readily than 1 ,5-dipolarcyclization in these conditions. Pyridinium disubstituted N-ylides, readily obtainedfrom corresponding pridinium and β-chlorovinyl ketone, underwent thermalintramolecular 1,5-dipolar cyclization to give indolizine derivatives easily.Indolizinecarbaldehyde derivatives were synthesized starting from 2-pyridinecarbaldehyde in four-steps involving 1,3-dipolar cycloaddition reaction.

本文首次研究了2-(2-芳基乙烯基)吡啶N-叶立德在氧化剂存在下的分子内1，5-偶极环化反应，采用一锅法合成了中氮茚衍生物；研究了这些N-叶立德的1，5-偶极环化和1，3-偶极环加成反应的选择性，发现当有缺电子烯烃存在时，优先进行1，3-偶极环加成反应，而不再发生分子内1，5-偶极环化反应；由β-氯乙烯酮方便地得到了烯丙基N-叶立德，他们在加热时进行分子内1，5-偶极环化反应而得到中氮茚衍生物；由2-吡啶甲醛为起始原料，通过1，3-偶极环加成反应等四步反应，得到了重要的中氮茚甲醛衍生物，这些反应都具有条件温和和操作简便的特点，是合成中氮茚衍生物的新方法。

Essay discusses the development trends of service trade in the process of economic globalization, include acceleration trend,high technology trend,unbalancing trend,structural optimizing trend and trade barrier enshrouding trend.

全球化时代服务贸易的发展趋势——兼论我国服务贸易的发展思路论文全球化，服务贸易的趋势主要有五个方面，即发展加速化、高化、非平衡化、结构优化和贸易壁垒的隐蔽化。

In the step of esterification, dehydration of boric acid and then esterifying with phenol were carried out in order to increase conversion of esterification. Effect of reaction temperature, consumption of boric acid, kinds and consumption of dehydrolating agent on the yield of esterification was studied. The experimental results showed that high conversion of 98% of esterification was obtained.

本实验将酯化反应分解为脱水反应步骤和酯化反应步骤，以便提高酯化反应收率，同时，考察了反应温度、硼酸用量、带水剂种类及用量对酯化反应收率的影响，实验结果表明，该步反应条件简便易操作，反应转化率达98%。

The influence of CFC-12 content, effect of fluorination temperature and fluorinating time on the structure and hydrodesulfurization activity of the catalysts were examined systematically. The results revealed that hydrodesulfurization activity of the catalyst fluorinated by 1% CFC-12 at 623 K was obviously improved With an increase of 20%-30% as compared With that of the unfluorinated catalyst, the commercially available BY2 catalyst, and NH4F-fluorinated catalysts.

通过对0.5%~7%各种氟里昂浓度和473~773K各种温度及不同时间氟化处理的样品进行详细考察，发现在623K下由含氟里昂1%的湿空气氟化的载体制备的催化剂样品，其噻吩的加氢脱硫的活性有明显改善，相对於非氟化样品、BY-2工业催化剂以及氟化铵溶液浸渍处理的催化剂活性提高20%~30%，且非常稳定。

Chiral nonracemic fluoro-organic molecules with a fluorine atom on a stereogenic center are readily prepared via chiral electrophilic fluorinating reagent-mediated enantioselective fluorinations, substrate-controlled enantioselective electrophilic fluorinations, chiral metal complexes and asymmetric catalyst—directed catalytic enantioselective fluorinations.

高光学活性的手性氟化物可通过手性亲电氟化试剂诱导的立体选择性氟化反应，基于底物的手性氟化反应以及手性催化剂诱导的不对称催化氟化反应等来制备。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。