玉米淀粉基阴离子高分子絮凝剂的合成及应用

研究了以玉米淀粉、氯乙酸和氢氧化钠的原料,利用溶液剂法合成羧甲基淀粉钠的方法及其在污水处理方面的初步应用,讨论了反应投料比、温度、时间等对反应取代度的影响。实验所得,优化条件为：投料比：m(淀粉）:m（氯乙酸）:m(氢氧化钠）=10:1.2:1.44,反应渡为50℃,反应时间为16h,所得的产物转化率可达75%。     

玉米淀粉基阴离子高分子絮凝剂的合成及应用

研究了以玉米淀粉、氯乙酸和氢氧化钠为原料 ,利用溶剂法合成羧甲基淀粉钠的方法及其在污水处理方面的初步应用 ,讨论了反应投料比、温度、时间等对反应取代度的影响。实验所得 ,优化条件为 :投料比 :m(淀粉 )∶m (氯乙酸 )∶m(氢氧化钠 ) =10∶1.2∶1.44 ,反应温度为 5 0℃ ,反应时间为 16h ,所得的产物转化率可达 75 %     

一种新型全集成高速双模分频器

A fully integrated 2n/2n+1 dual-modulus divider in GHz frequency range is presented.The improved structure can make all separated logic gates embed into correlative D flip–flops completely.In this way,the complex logic functions can be performed with a minimum number of devices and with maximum speed,so that lower power consumption and faster speed are obtained.In addition,the low-voltage bandgap reference needed by the frequency divider is specifically designed to provide a 1.0 V output.According to the design demand,the circuit is fabricated in 0.18 m standard CMOS process,and the measured results show that its operating frequency range is 1.1–2.5 GHz.The dual-modulus divider dissipates 1.1 m A from a 1.8 V power supply.The temperature coefficient of the reference voltage circuit is 8.3 ppm/°C when the temperature varies from40 to C125°C.By comparison,the dual-modulus divide designed in this paper can possess better performance and flexibility.     

文氏棒塔板流体力学性能研究

Dual flow trays are usually used in separation processes with serious fouling problem. The structure of the tray, typically the open slot configuration, is important factor to affect the performance. In this paper, one type of venturi-rod deck tray was designed. The hydrodynamic characteristics of this tray were investigated with experiment and compared with conventional sieve tray. Results showed the turndown ratio of this tray was at the range of 2.71~3.77, which was 9% higher than the sieve tray. Besides, the pressure drop of this tray was more than 50% lower than the sieve tray. Based on the experiment data, correlation functions for the pressure drop and froth height were obtained, respectively. Industrial scale up practice of this tray in the flue gas desulfurization (FGD) process was presented and demonstrated the efficiency of this tray.     

海绵城市建设评估要点分析与研究

根据政策与技术标准,秉持理念化、系统化、全域推进的指导方针,对海绵城市建设成效指标体系进行分析解读,并提供本底资料收集、排水分区划分、下垫面分析与年径流总量控制率评估、天然水域分析与效果评估的可行性方法,以此对海绵城市建设成效进行科学评价.     

煤炭企业应该特别关注的两个纳税筹划项目

纳税筹划是企业在合法的前提下,通过对经营事项的事先筹划、选择和管理,追求税收负担最小化的经济管理活动。而享受税收优惠政策是筹划中的重要技术,如何享受并充分利用政策的优惠幅度是企业应该关注的。鉴于煤炭企业的生产经营特点,笔者认为在技术改造国产设备投资抵免和资源综合利用项目上有充分的筹划空间,值得企业特别关注。     

秸秆接枝丙烯酸丁酯制备吸油树脂

以玉米秸秆为反应基材、丙烯酸丁酯为接枝单体、二甲基丙烯酸1,4-丁二醇酯(BDDMA)为交联剂,采用悬浮聚合方法合成了吸油材料。考察了物料配比、引发剂用量、交联剂用量、反应温度等因素对合成材料吸油性能的影响,用傅里叶变换红外光谱仪和扫描电镜分别对材料的化学结构及表面形貌进行了表征。结果表明,吸油材料的最佳合成条件为m(秸秆)∶m(丙烯酸丁酯)=1∶1、w(引发剂)=0.6%、w(交联剂)=0.2%、反应温度75℃、反应时间6h,在此条件合成的吸油材料对甲苯的吸油率为5.8g/g。     

EVA类降凝剂对生物柴油低温流动性的作用机理

通过预筛选试验确定了乙烯-醋酸乙烯酯(EVA)类降凝剂对生物柴油低温流动性的改善作用。采用差热分析(DSC)、低温X光衍射仪(XRD)、偏光显微镜等表征方法研究了EVA类降凝剂对生物柴油的降凝机理。实验结果表明,降凝剂加入生物柴油后没有减少蜡晶的析出量,而是通过与脂肪酸甲酯之间的共晶作用,改变了蜡晶的生长习性和聚集方式。蜡晶的外观呈现类球状,表现出优异的分散性,蜡晶之间不易交联,进而降低了生物柴油的冷滤点和冷凝点。     

利用玉米秸秆制备羧甲基纤维素

以玉米秸秆为原料,预处理后原料中纤维素质量分数由39%提高至81%,探讨了物料配比、醚化与碱化反应温度及时间等因素对产品取代度和黏度影响。实验结果表明,最佳反应条件为m(纤维素)∶m(NaOH)∶m(ClCH2COOH)=1∶1∶1,以异丙醇为溶剂,采用二次加碱法的工艺,两次加碱的质量比为2∶1,碱化温度30℃、时间60 min,醚化温度65℃、时间120 min。按最佳条件反应制得的产品取代度可达1.34,25℃下2%水溶液黏度可达690 mPa.s,并通过红外谱图验证了产品的结构。