Effect of rubber particles on cement stabilized gravel system

The primary objective of this paper was to study the mechanical properties and durability of the cement stabilized gravel by different compact method. The influence of rubber particle content on mechanical properties of samples was studied by compaction tests and freezing thawing recycle tests. Pore structure and fractal characteristic of mixture were analyzed quantitatively using mercury intrusion porosimetry （MIP）. X-ray diffraction （XRD） was adopted to identify the composition phases. The morphology analysis in micro scale and elemental analysis of samples were carried out by scanning electron microscope （SEM）. The optimum compressive strengths of rubber cement stabilized gravel （RCSG） with static compaction method and with vibratory compaction method were obtained by controlling compaction degree and vibration time, respectively. From the compaction tests, the vibratory compaction method is preferred compared with the static compaction method as better compressive strength can be improved by about 340%-360%. Besides, test results also reveal that compressive strength of samples with vibratory compaction method or static compaction method will decrease with the rubber particle bulk content increasing. The freezing thawing recycle tests indicate that freezing thawing resistance has been improved （frozen stability coefficient K has been increased from 0.89 to 0.97） by the addition of rubber particles. MIP tests show that the mean pore diameter and porosity of mixture have been increased from 70 to 250 nm and 9% to 24% respectively, with the rubber particles content increasing. Component analysis shows that the calcium silicate hydrate （CSH） is the predominant hydrate product with or without the addition of rubber particles.     

Thermal Insulation and Strength of Autoclaved Light Concrete

The primary objective of this study was to develop an autoclaved light concrete (ALC) material with ultra-thermal insulation property and to investigate the relationship between its physical characteristics and mechanical properties. Through tests of dry bulk density and compressive strength, relationship of physical characteristics and mechanical properties of samples were studied, resulting in a material with ultra-thermal insulation property. Scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDX) were applied to analyze the micro-morphology and elemental composition of samples. To identify the product phases, X-ray diffraction (XRD) was engaged. The test results showed that compressive strength and thermal coefficient were reduced with the increasing of aluminum powder within the mixtures. As a result the optimal thermal coefficient and compressive strength of samples were improved to 0.061 W/(m·k) and 1.2 MPa, respectively. SEM, EDX and XRD analyses showed that calcium silicate hydrate and tobermorite crystal were main resultant phases.     

手性色谱柱法测定L-苯丙氨酸的光学纯度

目的建立用手性色谱柱法(CSP)来测定L-苯丙氨酸光学纯度的方法。方法采用SUMICHIRAL OA-5000手性色谱柱,流动相为1mmol/L硫酸铜水溶液-异丙醇(87:13),检测波长为254 nm,结果 L-苯丙氨酸与D-苯丙氨酸分离度为4.615,保留时间L-苯丙氨酸10.383 min,D-苯丙氨酸16.067 min。结论本法简单快捷,重现性好,可用于生产中控制L-苯丙氨酸的光学纯度。     

正交设计法筛选克感愈胶囊提取工艺的研究

目的筛选克感愈胶囊的最佳提取条件,以确保生产工艺节能降耗,保护城市环境。方法对影响提取效果的主要因素加水量、煎煮时间和醇沉浓度进行三因素三水平设计,以绿原酸百分含量为指标,用L9(34)表安排实验,筛选最佳提取工艺。结果最佳提取工艺条件为水提取2次,每次水量10倍,每次提取2 h,醇沉浓度为70%。结论该工艺合理、可靠,操作简单,成本低,排放污染物少,适合工业化生产。     

正交设计法筛选克感愈胶囊提取工艺的研究

目的 筛选克感愈胶囊的最佳提取条件,以确保生产工艺节能降耗,保护城市环境.方法 对影响提取效果的主要因素加水量、煎煮时间和醇沉浓度进行三因素三水平设计,以绿原酸百分含量为指标,用L9(34)表安排实验,筛选最佳提取工艺.结果 最佳提取工艺条件为水提取2次,每次水量10倍,每次提取2h,醇沉浓度为70％.结论 该工艺合理、可靠,操作简单,成本低,排放污染物少,适合工业化生产.     

无功补偿与去磁电流协同控制的改进DFIG高电压穿越策略

为解决双馈感应发电机(DFIG)难以满足严重电网电压骤升故障时穿越测试要求问题,提出了基于无功补偿与去磁电流协同控制的改进DFIG高电压穿越控制策略。在网侧变换器无功补偿稳定直流母线电压的基础上,协同转子侧变换器去磁电流控制,确保有功功率平衡及RSC容量完全利用情况下向转子注入无功。对比传统方法,改进控制策略有严重骤升故障适应性强与转子侧变换器(RSC)容量利用率高的双重优势。最后在Matlab/Simulink搭建模型,仿真结果验证所提方案能更好地满足风电机组HVRT的测试要求,实现高电压穿越。     

改性橡胶混凝土的物理力学性能

通过对橡胶表面进行改性处理,改善了其与水泥基材的界面黏结,提高了混凝土的强度;研究了橡胶粒径、掺量、龄期等对橡胶混凝土物理性能和力学性能的影响,以及橡胶混凝土的变形性能.结果表明,5 d龄期时,15%～60%橡胶掺量(体积分数,下同)下的改性橡胶混凝土抗折强度可提高13%～39%,抗压强度可提高11%～40%;35 d龄期时,30%橡胶掺量下的韧性可提高31%.     

注重地域性城市建筑环境建设

期待未来的建筑环境建设应具有北方的地域和风情 ,标志性建筑、环境 ,是城市 ,也是旅游者寻求的亮点 ,单体建筑与总体环境和谐协调 ,是今后城市建筑环境建设所应注重的     

蛤蜊中金属营养元素的影响因素及来源

探讨产地、季节、品种对蛤蜊中金属营养元素含量的影响,解析蛤蜊中金属营养元素含量与养殖地淤泥和海水中相关元素含量间的关系。于2014年5月和9月在青岛市、南通市和大连市海岸采集花蛤、文蛤及养殖地淤泥和海水样品,测定样品中金属营养元素含量,分别进行方差分析和Pearson相关分析。结果显示,蛤蜊中Mg、K、Ca、Mn、Fe、Cu、Zn含量受产地的影响,Ca、Cu、Zn含量受季节的影响,Mg、Ca、Mn、Fe、Cu、Zn含量与品种有关;Na、Mg、Ca、Co、Cu含量与淤泥中相关元素的含量密切相关,而10 种金属营养元素含量与海水中相关元素含量相关性均不显著。本研究表明,蛤蜊中金属营养元素含量受产地、季节、品种的影响,其来源除淤泥、海水外,还有其他途径。