Synthesis and aqueous solution behaviors of sodium sulfonate‐terminated dendritic poly(ester‐amine)

Sodium sulfonate‐terminated dendritic poly(ester‐amine) (SPEA) was synthesized by sulfonation of acrylic double bond‐terminated dendritic poly(ester‐amine) (APEA) with sodium hydrogen sulfite (NaHSO₃) in mixture of diglycol and 2‐butanone under normal pressure. The structure of SPEA was characterized by IR, ¹H‐NMR, and elemental analysis. SPEA was water‐soluble. 1.0–40.0% (mass) SPEA aqueous solutions appeared as dilatant fluid. When pH value varied from 1.5 to 12.0, the viscosity of 1–5% (mass) SPEA aqueous solutions changed very small, and the electric conductivity almost kept stable within pH 3.0–10.0. The relationship between the viscosity and the concentration of SPEA water solutions was similar to that of NaCl water solutions. The surface tension of SPEA water solutions was lower than that of polyethylene glycol 2000 water solutions with the same concentration. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

用改进的预分频器和前置放大器实现低相位噪声的CMOS频率合成器

一种低相位噪声锁相环频率合成器的设计与实现,该设计利用了新型的前置放大器与预分频器,在采用TSMC0.35!mCMOS工艺的情况下,带宽为20MHz～920MHz。     

连轧管机轧辊轴承的调整、维护及保养

本文介绍了应用于MPM连轧机轧辊上的四列圆锥滚子轴承的结构特性及其调整、维护、保养，旨在提高轴承的使用寿命。     

高速列车风量控制式通风系统的探讨

介绍了能够减轻乘坐高速列车时产生的耳朵不适感的风量控制式通风系统，该系统通过检测车内外的压力来控制进排气量，并且由模拟计算证实，该系统能够控制车内压力的波动，满足高速列车的舒适性需要。     

水溶液中硅酸溶解和胶结的实验研究

本研究了几种不酸ＰＨ值对硅酸胶结的影响。结果表明，草酸浓度增大时，硅酸胶结速度变缓，至ＰＨ３－４时，硅酸不再胶结；而ＨＣＬ浓度增大，虽然胶结速度变缓，但最终仍胶结。     

准分子激光心血管治疗机的研究

研制了一台准分子激光心血管治疗机（ＸｅＣｌ３０８ｎｍ），单脉冲能量：８０－２００ｍＪ，平均功率５Ｗ，重复频率：手动单次，１－１００Ｈｚ，单次充气工作寿命：＞１０６脉冲数，脉冲－脉冲的能量不稳定度３％，激光脉宽１５０ｎｓ，光斑发散角（半角）：１．８×０．６ｍｒａｄ，光纤耦合输出＞２０ｍＪ。     

Study on phase behavior–impact strength relationship of unsaturated polyester/polyurethane hybrid polymer network

The phase behavior of a hybrid polymer network (HPN) composed of poly[(propylene glycol maleate)-co-(propylene glycol phthalate)] crosslinked with styrene and polyester–urethane crosslinked with methylene-bis-ortho-chloroaniline was examined. The correlation between phase separation and impact strength of the HPNs is discussed. The composition of HPNs has an effect on their properties.     

图象信息与光电子技术

本文阐述图象信息的重要性，说明它与光电子技术的关系，包括图象信息的获取、传输、存储与显示，展望了未来。     

三峡地区脆弱生态环境问题初探

脆弱生态环境是一种对环境因素改变的反应敏感而维持自身稳定的可塑性小的生态环境系统，三峡地区脆弱生态环境的基本特征为：侵蚀作用强烈；抗干扰能力弱；土地退化，土地生产力衰减；森林生态系统衰退，环境灾害加剧，灾种增多，频次增高，形成三峡地区脆弱生态环境的因素包括地质地貌因素，气候因素以及人为因素和社会经济因素，三峡地区生态环境的整治措施主要包括：控制人口增长；调整产业结构；开展综合治理；唤起环境意识，依