Synthesis of ZnWO4 nano-particles by a molten salt method

ZnWO₄ nano-particles were successfully synthesized by a molten salt method at 300 °C. The as-prepared powders were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and photoluminescent spectra techniques (PL), respectively. The size and morphology of ZnWO₄ nano-particles were affected by such conditions as the calcining time and the weight ratio of the salt to the ZnWO₄ precursor. The resultant sample is a pure phase of ZnWO₄ without any impurities. The PL spectra results showed that the optical property of ZnWO₄ crystallites obviously relied on their particle sizes.     

大型金相试样切割机控制系统设计

针对大型金相试样切割机的控制要求，采用OMRONCPM2APLC和NS10-V1触摸屏相结合的控制方式，为该型金相试样切割机设计了控制系统。控制系统以PLC为核心，触摸屏作人机交互界面，PLC用于完成数据处理和控制任务，触摸屏完成操作和显示功能。采用变频调速技术对驱动切割片的电机进行无级调速。采用细分式驱动技术控制X向、Y向、Z向的步进电机运动。     

Assessing photosynthetic light-use efficiency using a solar-induced chlorophyll fluorescence and photochemical reflectance index

Photosynthetic light-use efficiency (LUE) is an important indicator of plant photosynthesis, but assessment by remote sensing needs to be further explored. In this study, two protective mechanisms for photosynthesis, chlorophyll fluorescence (ChlF) and heat dissipation in the deep oxidation state of the xanthophyll cycle, were explored to estimate photosynthetic LUE from canopy radiance spectra. Four independent experiments were carried out on summer maize (C4 plant) on 5 July 2008, and winter wheat (C3 plant) on 18 April 2008, 16 April 2010, and 13 May 2010, by synchronously measuring daily canopy radiance spectra and photosynthetic LUE. The competitive relationship between ChlF and photochemical yield made it possible to estimate photosynthetic LUE. LUE–ChlF models were developed for ChlF at 688 nm (R ² = 0.72) and 760 nm (R ² = 0.59) based on the experimental data from 13 May 2010 at the Guantao flux site. The LUE–ChlF models were validated by three independent experiments, and the results showed that the LUE–ChlF relationship was weakened, possibly by variation in species, canopy density, and environmental conditions. As an easy, rapid, non-intrusive method, a photochemical reflectance index (PRI) provides an instantaneous assessment of dynamic photosynthetic LUE. The significant negative relationship between non-photochemical quenching and PRI was confirmed. Although there was a significantly positive relationship between LUE and PRI in all four independent experiments, this was evidently weakened by the canopy and environmental conditions. Difference in PRI (ΔPRI) from the minimum reference PRI around noontime can largely eliminate interference factors. The LUE–ΔPRI model was developed based on experimental data from 13 May 2010 at the Guantao flux site (with an R ² value of 0.85), and validated by the three other independent experiments. The validation result indicated that different species can markedly affect the precision of the PRI difference method.     

保定市城市生活垃圾处理现状及对策建议

城市生活垃圾的科学处理,对城市的生态环境和居民的身心健康有着重大意义.本文对保定市当前城市生活垃圾的收集、运输和处理状况进行分析,指出了存在的问题,在此基础上借鉴国内外生活垃圾处理方面的先进经验,提出了对策和建议,促进保定市生活垃圾处理的科学发展和进步。     

基于极限平衡法的折线形滑坡体 稳定性分析

应用极限平衡法推导出当无粘性土坡部分浸水时，其滑动面为两直线组成的折线形滑动面稳定安全系数的计算模型，并提出确定最小安全系数以及相应滑动面的方法。通过实例分析表明，其计算结果符合工程实际。     

Efficient reductions of various nitroarenes with scrap automobile catalyst and NaBH4

The effect of scrap automobile catalyst (SAC), a waste material, was investigated as a catalyst for the reduction of nitroarenes to the corresponding amines with sodium borohydride in aqueous ethanol at 5–25 °C. Along with the observed high conversions, the SAC and NaBH₄ combination also exhibits a selectively catalyzed reduction in compounds containing other reducible functionalities, such as CN, Br, Cl and I. Recycling automobile wastes into a catalyst for organic reactions will offer both environmental protection and economic advantages. As a result, an effective, easy to use, low-priced and reliable method has been developed.     

辣椒疫霉对杀菌剂抗药性研究进展

综述了近年来国内外辣椒疫霉菌对苯基酰胺类、甲氧基丙烯酸酯类、丙烯酰胺类内吸性杀菌剂的抗药性发生现状、抗药机理、抗药遗传等方面的研究进展.对辣椒疫霉菌抗药性研究和制定抗药性治理对策以及化学防治具有一定的参考价值,同时指出了今后的研究方向和发展前景.     

浅谈坝上地区节水型农业模式

近年来随着人口的增长和社会经济的快速发展,目前人类正面临着越来越多的来自社会经济系统的水资源问题。河北省张家口市坝上地区位于内蒙古高原南缘,干旱、少雨、低温是制约当地农业生产的主要因素。该区工业基础薄弱,经济欠发达,是河北省水资源短缺,生态环境脆弱的地区。全社会用水总量逐年增加势头加剧,供用水矛盾,行业间用水矛盾日益突显。如何处理经济社会可持续发展与人水和谐相处之间的关系,是摆在各级政府面前的重要课题。以近年来在该区开展的不同灌溉类型用水效率测试资料为依据,总结了农业定额管理,总量控制和政策节水方面的经验和成果。提出了行之有效的节水型农业发展模式,以逐渐解决水资源供需矛盾,从而实现区域经济社会的可持续发展。     

Improving performance of proton ceramic electrolysis cell perovskite anode by Zn doping

As an important renewable energy, hydrogen energy becomes an important part of the future energy system. Proton ceramic electrolysis cell (PCEC) enables the efficient, clean, large-scale preparation of hydrogen, which is a new type of energy conversion device, attracting the attention of many researchers. Sr₂Fe_1.4Zn_0.1Mo_0.5O_6-δ (SFZM) anode materials were developed to investigate the effect of B-site doping of Zn on the electrochemical properties of the Sr₂Fe_1.5Mo_0.5O_6-δ (SFM) materials. The results reveal that the doping of Zn increases the concentration of oxygen vacancies and improves the electrocatalytic activity, which in turn improves the performance of the material. A current density of 408 mA cm⁻² has been achieved at 1.3 V when the SFZM-based single cell was operated in an electrolysis mode (50% H₂O in air) at 600 °C, higher than SFM-based single cells (286 mA cm⁻² at 1.3 V). In addition, the SFZM-based single cell exhibited good durability in a stability test at an electrolysis current density of 408 mA cm⁻². This work confirms that SFZM is a promising material for proton ceramic electrolysis cell anode.