环

Nitratomethyl-3-ethyloxetane was synthesized by the process of cyclization, nitation from trimethlolpropane and diethyl carbonate, and the homopolymer of 3-nitratomethyl-3-ethyloxetane was synthesized with 1,4-butanediol as initator and boron trifluoride etherate as an catalyst by cationic ring-opening polymerization.

以三羟-甲基丙烷和碳酸二乙酯为原料经环化、硝化两步反应合成了化合物3-硝酸酯甲基－3-乙基氧丁环；采用1，4-丁二醇为引发剂，三氟化硼乙醚(BF3Et2O)为催化剂，NIMEO发生阳离子开环聚合得到一种端羟硝酸酯均聚醚PNIMEO。

The catalysts such as tetraphenyl tin,aluminium isopropoxide and boron trifluoride etherate complex were used to catalyze the copolymerization.In addition,the copolyester can be given by copolycondensation after monomers were hydrolyzed by phosphoric acid.Boron trifluoride etherate complex was chosen as the catalyst because the catalytic activity was the best among the catalysts.

由于γ-戊内酯为五元环结构，难以进行开环聚合，因此分别考察了四苯基锡、异丙醇铝、三氟化硼乙醚络合物等催化剂，以及以磷酸为催化剂的水解缩聚反应，结果发现三氟化硼乙醚络合物的催化活性最高，因此选择三氟化硼乙醚为本体开环聚合的催化剂。

He TSS is designed to replace cheaper and simpler sealing products available on the market.

SS 索环旨在替换目前市场上价格低廉、设计简单的索环产品。TSS 索环是一种新型的，适用

Snap hook, quick link, shackle, rigging screw, turnbuckle,"S" hook, swing hook, thimble, swivel hair pin, linch pin, clip, wire rope, chain.

8E14 8E16 弹簧钩，连接环，卸扣，花兰，"S"钩，秋千钩，套环，转环，发夹，折叠扣，卡头，钢丝绳，链条。

This paper studied on domestication of plantlets in tissue culture and rapid propagation of Dendrobium loddigesii Rolfe which dealed with the different medium composed of gravel, rotten soil, perlite, turves, sawdust and china clay, in the different light intensity and temperature. The results showed that the best selection of medium on the domestication was 10cm gravel in bottom, rotten soil + sawdust + perlite,(5:1:1) in the middle part ,5cm greenness bryophyte on the surface.the best selection of medium on the transplantaion of plantlets in vitro of bramble,and light intensity was employed harf overshadow by adumbral net,temperature confined 14℃－28℃.

本文研究了环草石斛组培苗炼苗的影响因素如光照强度，温度以及基质等，初步获得环草石斛组培苗炼苗生产技术：能进行人工光、温、水控制的如塑料薄膜大棚内进行环草石斛组培苗炼苗，光照强度的要求是使用遮阳网半遮阴；温度控制在14℃－28℃；出瓶苗要求株高2～5cm，叶片4～7，根数3～8；组培苗炼苗基质为底层是约10cm厚的碎石，在碎石上面是腐殖土+锯末+珍珠岩(5：1：1)，最上面是一层5cm厚的新鲜苔藓。

RESULTS: The AF cells cultured in different substrates were morphologically undistinguishable. Toluidine blue staining showed that there was also no difference between AF cells cultured on flexible silicone membranes and in plastic plates. The cells growing in different substrates expressed the same levels of collagen typeⅠ,Ⅱ and aggrecan mRNA and integrin β1. AF cells grew well on silicone membranes.

结果：种植于不同基质的纤维环细胞形态学观察无明显差别；在两种基质上的纤维环细胞甲苯胺蓝染色无差异；Ⅰ，Ⅱ型胶原及聚集蛋白聚糖mRNA及细胞膜整合素β1的表达亦无明显差异；纤维环细胞可以黏附于硅橡胶膜上生长。

The study of fluorescence spectrum proved that the excited phenylenerings of amorphous PES copolymer with high density phenylenerings in its main chain could form an excimer with the surrounding unexcited phenylenerings, and the emission peak intensity of excimer was strengthened with the increase of aging time.

荧光光谱的研究证明，非晶态聚醚砜共聚物由于主链苯环密度较高，苯环受激处于激发态时易与周围激态苯环相互作用形成激基缔合物，缔合物发射峰的强度随老化时间增加而增强。

The study of fluorescence spectrum proved that the excited phenylene-rings of amorphous PES copolymer with high density phenylene-rings in its main chain could form an excimer with the surrounding unexcited phenylene-rings, and the emission peak intensity of excimer was strengthened with the increase of aging time.

荧光光谱的研究证明，非晶态聚醚砜共聚物由于主链苯环密度较高，苯环受激处于激发态时易与周围激态苯环相互作用形成激基缔合物，缔合物发射峰的强度随老化时间增加而增强。

We discussed the stability of the system balance, used the Poincare-Bendixson's annular region theorem to prove the existence, and used the Zhang Zhifen unicity theorem to prove the uniqueness of limit cycle, at the same time give meaning to the corresponding conclusions on the ecology.

讨论了系统平衡点的稳定性，用Bendixson环域定理证明极限环的存在性，借助张芷芬唯一性定理证明极限环的唯一性，同时对相应结论的生态学意义给予说明。

The existence and uniqueness of the limit cycle are proved by applying Poincare-Bendixson theorem and Zhang Zhifen's Uniqueness theorem.

运用Poincare-Bendixson环域定理，证明了极限环的存在性。这用张芷芬惟一性定理，注明了极限环的惟一性。

Do you know, i need you to come back

你知道吗，我需要你回来

Yang yinshu、Wang xiangsheng、Li decang,The first discovery of haemaphysalis conicinna.

1〕 杨银书，王祥生，李德昌。安徽省首次发现嗜群血蜱。