化学

In the cyclization process,α-acylamino radicals preferred to attack acylsilanes from the face opposite to the β-substituent, and the stereoselectivity of the bridgehead is excellent. The orientation of the hydroxy group formed in the cyclization process was mainly exo.

生物碱架桥上立体化学的建立，可透过环上取代基立体障碍的影响，使得环化过程只会从立障较小的一面进行，因此可得到单一立体化学的结果，而环化所形成的羟基则是以exo的产物为主。

Efficacious drugs were made of these species for treatment of cough, phlegm, breathe heavily, especially, to cure lung disease. We have investigated on the Chemical constituents of Adenophora stenanthina subspecies xifengsis collected from Gansu Qingyang, and twenty four compounds were isolated from ethanol extraction by chromatography technigues. Twenty compounds were identified by means of chemical and spectra methods（IR, FAB-MS, EI-MS,〓,〓, DEPT , among which three compounds were new as 3βvanilloyloxy-stigmast-5-ene-7β-one; 3β-Vanilloyloxy-stigmast-5-en-7 β-ol; 3β-vanilloyloxy-stigmast-5-en-7β, 15 〓-diol.

我们对采自甘肃庆阳的西峰沙参Adenophorastenanthina subsp.xifengensis）进行了化学成分的研究，利用现代层析手段从该植物的乙醇浸膏中分离出二十四个化合物，经化学方法和波谱技术（红外，质谱，核磁共振谱）鉴定了二十个化合物的结构，其中三个为新的化合物，它们分别是：豆甾-5-烯-7-酮-3β-香草酸酯；7β-羟基-豆甾-5-烯-3β-香草酸酯；7β，15ξ-二羟基-豆甾-5-烯-3β-香草酸酯。

The SEM-EDS showed that the content of surface elements was changed after treated with glutaraldehyde or albumin indicated that argon plasma only had surface cleaning effect and did not change surface composition and the allylamine deposition thickness was too thin to show the difference in SEM-EDS findings. The XPS results confirmed the argon plasma cleaning effect and revealed that the ratio and the binding energy of surface elements changed with different treatment procedures and were similar to what expected to coat on the titanium surface.

XPS更进一步证实，氩气电浆只有清洁钛金属表面的作用，并不会改变其表面化学组成；其余各组的钛、碳、氮、氧的比例及键结能量随著处理程序而改变，可知表面上有化学组成之改变，且随不同处理程序所得到表面元素之百分比及键结能量，与预期的表面披覆物元素百分比及键结能量相近。

Chelate fiber with amidoxime group,which is obtained from chemical modification of PAN fiber,is treated with mercury nitrate to prepare anion-exchange fiber.The optimum conditions of the anion-exchange fiber absorption of the thiocyanate ion,such as ion concentration,time,the pH value were studied.

以聚丙烯腈纤维进行NH2OH化学改性制得的含有偕胺肟基的螯合纤维为原料，经Hg(NO3)2化学处理，制得阴离子交换纤维；并以硫氰酸根离子为研究对象，系统地探讨和研究了阴离子交换纤维吸附硫氰酸根离子的最佳条件参数：离子浓度、时间、pH值等。

Methods: cell biological assay, histochemical staining of senescence associated-β-galactosidase and immunohistochemical staining of proliferating cell nuclear antigen wereused. Results: chondrocytes exhibited various types of amitotic figures.

应用细胞生物学方法、衰老相关-β-半乳糖苷酶组织化学染色和增殖细胞核抗原免疫组织化学方法，研究正常成人和正常成体大鼠气管软骨组织动力学。

Objective To examine the important roles of microRNAs in regulating amphid structure and function, we performed a computational analysis for the genetic loci required for the sensory perception and their possibly corresponding miRNAs in C.

目的 为了系统评价microRNA在调控化学传感器结构和功能方面的重要作用，我们进行了线虫中有关影响化学传感器结构与功能的遗传位点以及和其可能对应的miRNA的生物信息学分析。

At the same time seventeen normal ampullary oviducts during mid-secretory phase were included as control group. The routine two-step immunohistochemical technique was performed.

采用电化学发光法检测术前血β-HCG及免疫组织化学二步法测定各组标本中VEGF的表达，根据阳性率和表达强度进行组织化学评分和相关性分析。

The experiment results show that the active reaction groups in chemical degradation canbe restrained by a little auxiliaries of ultraviolet resistant, heatproof antioxdant and antiager etc. which addedin PP.

加工温度选择是有效利用化学阵解剂来改善PP熔体流动性的重要条件之一，同时PP分子链与化学活性基团的降解现象是有温度依赖性的。

The hygienic and toxinfree Xinli PP-R pipes serial products are green and environmental construction materials, which have been recommended by the four ministries and commissions of the State Department, The products are heatresistant which means that the temperature of the supplied water can reach 95℃ under the specified long-term working hours, They are also corrosion-resistant and antiscale and can prevent any corrosion and rust in pipes, lavers and bathtubs.

&鑫利&PPR给水管系列产品，质量轻，20℃时的密度为0.89—0.91g/cm3，重量仅为钢管的九分之一，紫铜管的十分之一。由于重量轻，可大大减轻工人的施工强度。耐热性能好：瞬间使用水温可达95℃，长期使用时，当工作压力不大于0.6mpa时，水温可达75℃。这可满足一般生活、生产水温的需要，所以建筑给水PPR管一种较理想的热水管材。耐腐蚀性好：对水中的所有离子和建筑物内的化学物质均不起化学作用，不生锈、不会腐蚀。

In the expansive spaces,the sudden changes of chemical,physical and biochemical conditions lead to final destruction of the auriferous complex compounds and facilitate the precipitation and accumulation of natural gold in the shear belt.

在这些剪切带扩张空间内，由于化学的、物理的及生物化学条件发生突变，导致热液的地球化学平衡被破坏，促使自然金沉淀析出，并聚集在剪切带内构成矿床。

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％。