活性中心

The special interest devoted to acrolein arises from the fact that it is the shortest unsaturated aliphatic aldehyde.

如果氧化镁可表面中心和酸性沸石存在互补作用，这样催化剂的活性就可以得到解释。

In general, catalytic activities of iron complexes bearing electron-donating alkyl groups increase with the net charges increasing.

取代基的电子效应占主导作用的催化剂，活性与中心金属原子净电荷有较好的相关性。

These ligands were found to be very effective in construction of quaternary carbon centers by using asymmetric allylic alkylation.

这类配体在前手性亲核试剂的不对称烯丙基化构筑手性季碳中心的反应中，显示了较好的反应活性及对映选择性。

The ligands were found to be effective in palladium-catalyzed asymmetric allylic alkylation to construct chiral quaternary carbon center.

这类配体在前手性亲核试剂的不对称烯丙基化构筑手性季碳中心的反应中，显示了较好的反应活性及对映选择性。

A data acquisition and data analysis software for the fast fluorscence kinetics fluorometer of our laboratory is redesigned and recompiled using assembly and BASIC language. The data acquisition rate in the fast rising part of the fluorescence kinetics curves is one order faster (100μs/point) than the old one. It can measure fluorescence parameters, such as Fo and Fi more accurately for calculation of the relative content of inactive PSⅡ, etc.

用N80-BASIC语言结合汇编语言重新编写了本室快速叶绿素动力学荧光计的测控程序，使快速荧光上升曲线的采样速度提高了一个数量级（达到100μs／点），可对Fo、Fi等关键荧光参数进行精确测定，为无活性PS Ⅱ中心相对含量的准确测定奠定了基础。

Clinical Medicine Laboratory Center,The People's Hospital of Guangxi Zhuang Nationality Autonomous RegionAbstract:Objective To study relationship with the gastric cancer patients stool Helicobacter pyloripositive rate and changed Glycyl proline dipeptidyl aminoeptidas activities of serum.

广西壮族自治区人民医院临床医学实验中心目的探讨胃癌患者粪便Hp检出率与血清GPDA活性变化的关系。

Effects of three levels of nitrogen nutrition on xanthophyll cycle and the antioxidant system in strawberry leaves growth in elevated CO2.(4) Response of Dl turnover to high light in strawberry leaves.

结果表明，Fm、Fv/Fm、PS Ⅱ无活性反应中心数量和Q_A的还原速率在强光下降低，在暗恢复时升高；而PS Ⅱ反应中心非还原性Q_B的比例在强光下增加，在暗恢复时降低。

The study shows that: evergreen broad-leaved species during the middle and later period succession have better adaptability under the different light surroundings, such as Elaeocarpus glabripetalus, Ilex integra, Photinia prunifolia, Cinnamommum camphora. And Fluorescent Characteristics also verifies the above result. The experiment results indicate that: PSⅡreaction centers of majority tree species are not marked oxidized under the full light surroundings. Photosynthetic electron transport activity can maintain highly, in this way, it is helpful to enhance radiant energy dissipation and thus dissipate excess light energy. That is to say, the increase of non-photochemical quenching coefficient can conduce to protect PSⅡ, and mitigate the effect of high light on photosynthesis.

研究发现处于演替中后期的常绿阔叶树种幼苗，对光环境的变化均有着较强的适应能力，秃瓣杜英、全缘冬青、小叶铁冬青、桃叶石楠、香樟等树种的表现尤为突出；荧光特性的研究也应证了这一观点，测定结果表明多数树种的PSⅡ反应中心并未受到明显氧化破坏，在全光照条件下仍能维持较高的光合电子传递活性，能通过提高非辐射性热耗散，消耗PSⅡ吸收的过剩的光能，从而保护PSⅡ反应中心免受因吸收过多光能而引起的光氧化伤害。

A modified γ-Al〓O〓 was prepared by a special precipitation method with aluminum nitrate solution containing a certain amounts of orthosilicic acid and ammonia aqueous solution. Compared with commercial γ-Al〓O〓, the modified γ-Al〓O〓 was an effecient catalyst for dehydration of tetrahydrofurfuryl alcohol to dihydropyran. The results revealed that the strong acid sites on the surface of the catalyst may play a crucial role in this reaction.

并以硝酸铝和氨水为原料，用沉淀法制备出一种高比表面和拥有较多强酸中心的γ-Al〓O〓，它在四氢糠醇开环脱水制备二氢吡喃的反应中有优良的催化活性，通过比较此γ-Al〓O〓和普通商业γ-Al〓O〓的Py-TPD图，发现强酸中心在制备二氢吡喃的反应中可能具有关键的作用。

In the Aldol condensation of acetone with 4-nitrobenzaldehyde, two different hybrid secondary amine-functionalized mesoporous materials displayed enhanced catalytic performance in comparison to primary amine-functionalized materials. The possible reason is that the presence of organic functional groups with larger steric hindrance led to the enhanced catalytic performance of basic amino groups.

在对硝基苯甲醛和丙酮的羟醛缩合反应中，相对于一级胺功能化的材料，二级胺功能化的SBA-15展示了极大改进的催化活性，这可能是由于具有更大空间位阻效应的有机功能团的引人导致了碱性胺中心催化活性增强。

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％。