4-溴-4~’碘联苯的合成研究

对两种不同体系下合成4-溴-4’碘联苯进行了研究。通过对比发现,浓硫酸做催化剂,I2/KIO4为碘化试剂的反应体系具有可行性。对该体系的反应温度和浓硫酸的用量进行了优化。原料4溴联苯,在浓硫酸催化下,与碘/碘酸钾在冰醋酸水溶液中,于100℃下反应2h,紫色褪尽,过滤得到白色固体粗品34g,纯度98%(HPLC),收率为95%。该方法降低了原料成本,简化操作,缩短反应时间,是较为理想4-溴-4’碘联苯的工业合成方法。     

共沉淀法合成ZrO2-ZrW2O8复合材料的工艺研究

以硝酸氧锆[ZrO(NO₃)₂·5H₂O]和钨酸铵(H₄₀N₁₀O₄₁W₁₂·xH₂O)为原料,采用共沉淀法合成了低热膨胀的ZrO₂-ZrW₂O₈复合陶瓷, 着重研究了不同热处理条件对前驱体转变为ZrO₂-ZrW₂O₈复合陶瓷的影响, 并探讨了前驱体生成及其转变的反应历程. 通过X射线衍射仪(XRD)、热重-差示扫描量热(TG-DSC)、扫描电子显微镜(SEM)、热膨胀仪等分析手段对样品的晶体结构、物相转变、断面微观形貌和热膨胀性能进行表征. 结果表明: 采用共沉淀法制备的前驱体在1150℃热处理2h可以合成高纯度、混合均匀的ZrO₂-ZrW₂O₈复合陶瓷; 随烧结时间的延长, ZrW₂O₈衍射峰半高宽逐渐减小, 晶粒在不断长大; ZrO₂-50wt%ZrW₂O₈复合陶瓷在30～600℃内的平均热膨胀系数为-3.2295×10^-6K^-1.     

天生五味饮结合60分钟游泳运动对大鼠抵抗素的影响研究

目的:研究营养结合运动对胰岛素低抗素水平及CHO、TG的影响。方法:以天生五味饮结合中强度运动来干预用高脂饲料饲养的大鼠,观察其对大鼠血清抵抗素水平及血脂水平的作用。结果:天生五味饮中剂量组、高剂量组、中量合剂加运动组比实验对照组抵抗素水平明显下降(p<0.05);天生五味饮中剂量组比实验对照组CHO有显著下降(p<0.01);运动组比实验对照组TG大幅下降(p<0.01)。结论:营养与运动相结合对抵抗素及CHO、TG有良好的调节作用。     

凉拌毛笋改善大鼠血脂环境及抗氧化作用研究

目的:研究凉拌毛笋在调节血脂和抗氧化方面的保健作用,为应用毛笋进行营养配膳提供科学依据。方法:将凉拌毛笋掺和到饲料中饲养实验性高脂大鼠30d,测定血清TC、TG、HDL-c含量、肝脏SOD活力、GSH-Px活力、睾丸MDA含量。结果:凉拌毛笋能显著降低高脂模型大鼠血清中的TC、TG水平;能提高SOD、GSH-Px活力,降低MDA含量。结论:凉拌毛笋能够改善大鼠的血脂环境,有较好的抗氧化能力。     

基于RS-485的数字伺服驱动器通讯控制技术的研究

研究了伺服驱动器的RS-485通讯技术,实现了一台PC机控制多台伺服电机,利用C语言阐述了其编程方法和过程,结果表明控制伺服电机可行。     

Diversifying Top-k Routes with Spatial Constraints

Journal of Computer Science and Technology - Trip recommendation has become increasingly popular with the rapid growth of check-in data in location-based social networks. Most existing studies...     

Ammonium removal by a novel magnetically modified excess sludge

Disposal of nitrogen nutrient and excess sludge is a keen concern in wastewater treatment plants. This study describes a simple method of preparing an economical adsorbent, i.e., magnetic excess sludge (MES) by compounding the excess sludge with Fe₃O₄ nanoparticles. Ammonia–nitrogen removal from simulated wastewater was investigated by using the MES as an adsorbent. The MES had an adsorption efficiency of up to 90% for ammonium removal. Highly efficient separation of adsorbed ammonium on the MES could be magnetically separated from wastewater within 30 s. The operating conditions for ammonium adsorption were optimized at MES dose of 20 g/L, initial ammonium concentration of 45 mg/L and operating temperature of 298–308 K. The equilibrium data of ammonium adsorption on the MES showed a good agreement with the Langmuir isotherm, while the kinetic data were best fitted by the pseudo-second-order model. FTIR analysis indicated that various functional groups, such as hydroxyl and carboxyl groups, existed on the surface of the MES and contributed to the excellent capability for ammonium adsorption. These results suggest that the MES is a promising candidate for removing ammonium from wastewater and recycling excess sludge to ease its disposal at low cost.     

ISP1581与单片机接口在机械手示教盒中的应用

阐述了USB接口芯片ISP1581的特性和工作原理,并介绍了它与AVR单片机的软、硬件接口设计,该芯片与单片机接口连接方便,程序设计简单,实现了高速通信.     

基于孟塞尔色理论的产品调和配色研究

通过对孟塞尔色立体的分析,对产品色彩设计评价环节进行研究,以孟氏色系调和理论为基础,通过色力矩和审美度计算等方式,构建了色彩设计计算机评价的基础平台.