超声环流法提取牛蒡菊糖的研究

以牛蒡等外根为原料,经过预处理后,利用实验室自制超声环流反应器从中提取菊糖。选择超声功率、提取温度、提取时间、料液比和通气量等5个因素,在不同的水平下分次进行单因素试验,确定各因素的适宜范围,再由此采用正交设计法优化提取条件,结果表明：提取牛蒡菊糖的最佳因素组合为超声功率300 W,提取温度70℃,提取时间30 min,料液比1：20;在最佳因素组合下提取率达到57.89%,显著高于同等条件下传统热水浸提提取率5.23%及超声辅助提取提取率24.83%,为该方法的大规模工业化应用提供了理论依据。     

10%灭蝇胺悬浮剂急性毒性及致敏实验观察

按照《农药登记毒理学试验方法》（GB15670—1995）,对10％灭蝇胺悬浮剂进行急性经口、经皮、吸入毒性试验,眼睛刺激试验和致敏试验,了解10％灭蝇胺悬浮剂急性毒性及致敏性。大鼠经口LD50雌雄性均〉4640mg／kg,大鼠经皮LD50〉2000mg／ks,对家兔眼有轻度刺激作用,但无皮肤刺激作用。对豚鼠致敏试验,致敏率为0％。结果表明灭蝇胺属低毒农药。     

环氧琥珀酸共聚物的制备及对硫酸钡的阻垢作用

将环氧琥珀酸(ESA)、丙烯酸(AA)、丙烯酸羟丙酯(HPA)三种单体共聚,再将该三元共聚物与膦羧酸(PBTCA)复配,制备了一种阻垢剂EAHP。初步探讨了该阻垢剂对硫酸钡垢的阻垢机理。结果表明,在m_ESA:m_AA:m_HPA:m_PBTCA=1:0.5:0.5:0.5、催化剂的质量分数0.3%、温度88~93℃和反应时间4h时,可制得阻垢性能优异的阻垢剂。阻垢剂的加入量为15mg/L时,其对硫酸钡的阻垢率达到100%,远优于各种常见的阻垢剂,从而为原油开采中遇到的硫酸钡阻垢难题提供了一种解决办法。该阻垢剂对硫酸钡的优异阻垢性可能是—OH和—COOH基团及—O—基团共同作用的结果。。     

SD模型在陕西省土地利用总体规划中的应用

目的探讨系统动力学模型在省级土地利用总体规划中的应用。方法依据陕西省土地利用系统的现状和特点,在因果关系分析的基础上,建立陕西省土地利用系统动态仿真模型。结果应用动态仿真模型,分别从耕地保护、生态平衡和城乡建设发展的角度出发,设计了3个结构特征明显的规划方案。结论系统动力学模型用于省级土地利用总体规划是较为理想的方法,应用系统动力学模型做出的陕西省土地利用规划方案充分地体现了其土地利用的实际和未来发展变化的趋势。     

城市设计影响下的分层控规中土地使用强度评价研究——以宝鸡市陈仓组团为例

从编制技术层面对城市设计没有纳入新的分层控规编制体系和控规指标对城市空间形态控制方面的不足进行分析,构建了城市设计影响下土地使用强度的评价技术体系,运用定量评价融合定性判断的评价技术方法加强对土地使用强度的控制,分别从管理单元、地块层次验证具体操作方法。     

Risk-analysis-based research and application of land use planning

The establishments which produce,store and use kinds of inflammable,explosive or toxic materials may induce accident,such as fire,explosion or poisonous gas dispersion,etc. Therefore,there is a need to locate these establishments appropriately and conduct land use planning in the vicinity of these establishments based on risk analysis. Consulting advanced experience which obtained from land-use planning in European countries,this paper studied on locating hazardous establishment based on risk index,land-use...     

NI Multisim 10软件在单片机学习中的应用

重点介绍用电路仿真软件EWB的最新版本Multisim 10对单片机(51系列)做实时仿真;利用该软件可以随时随地进行单片机实验,这对单片机的学习和提高都有很大的帮助.     

NI Multisim 10软件在单片机学习中的应用

重点介绍用电路仿真软件EWB的最新版本Multisim 10对单片机（51系列）做实时仿真；利用该软件可以随时随地进行单片机实验。这对单片机的学习和提高都有很大的帮助．     

Microstructure and electrical conductivity of 10% Yb-doped SrCeO3 ceramics

As a candidate material for hydrogen separation, Yb-doped SrCeO₃ has attracted increasing attention in recent decades. In the present study, Yb-doped SrCe_0.9Yb_0.1O_3-α ceramics were prepared by the dry pressing and sintering approach, with the microstructure evolution and the micro morphology investigated. It was indicated that the ceramics sintered in air were of a pure perovskite structure, and that the sintering temperature had a significant effect on the growth of ceramic grains. The average grain size increased from 1 ​μm to 10 ​μm with an increase in sintering temperature from 1300 to 1500 ​°C. Further investigation of the thermodynamics and kinetics of grain growth revealed that the grain boundary diffusion was the main driving force of grain growth during solid phase sintering, with a grain growth index of 4 and an activation energy of approximately 61.23 ​kJ ​mol⁻¹. These results illustrate an obvious tendency of grain size growth. By electrochemical workstation with different atmospheres the effects of sintering temperature on the conductivity were characterized in the temperature range of 700–900 ​°C. The electrical conductivities σ of SrCe_0.9Yb_0.1O_3-α ceramics in different atmospheres were as follows: σ(wet hydrogen) ​> ​σ(dry hydrogen) ​> ​σ(dry air) ​> ​σ(wet air). In the test atmosphere containing water and hydrogen the conductivity of protons increased with increasing temperature because of the protons jump between lattices in the form of interstitial hydrogen ions or bare protons.     

顺应自然、因势利导,科学规划黄山现代国际旅游城市

黄山市具有旅游、生态、文化三位一体的独特优势,目前正在加快建设风景秀丽山水城市、历史悠久文化城市、现代国际旅游城市.该文从自然、文化、旅游资源特色等方面,探讨黄山城乡规划设计导向与原则,以促进黄山的健康持续发展.