Impact of Aspen Log Storage with and without Protection on OSB Performance

Outdoor log storage without protection can change the mechanical and chemical properties of wood due to infection by various fungi. To understand how outdoor log storage affects the wood and, subsequently, the strandboard quality, two piles of aspen logs were set up outside and stored for a period of four months (July to November). One of the piles was treated with a biological solution to prevent fungal growth. The other one was stored without treatment. Both piles contained non-debarked and partially debarked logs. Evaluation of sap stain development indicated that all logs had been colonized by staining fungi with average stain coverage of 9.37 to 57.18% and maximum stain penetration of 3.58 to 7.27 cm over the log cross section. The variation of fungal colonization depended on log treatment and bark condition. The most effective way to prevent stain growth was the combination of biological treatment and partial debarking. A series of strandboard was prepared from fresh and aged aspen logs. All boards made from stored logs were statistically comparable to or superior to the control boards made from fresh aspen logs. The boards made from treated/partially debarked and untreated/non-debarked logs were statistically comparable to each other except for wet MOR. In addition, these two board types were statistically stronger than other boards made from treated/non-debarked and untreated/partially debarked logs in terms of IB and water resistance. Some individual stained strands were observed on the finished board surface. Less staining was found in the boards prepared from biologically treated and partially debarked logs, compared with those made from other stored logs.     

加强电炉钢短流程生产工艺研究与技术开发的建议

论述了加强电炉钢短流程生产工艺研究与技术开发的必要性和主要课题，并提出关于组织合金钢短流程生产工艺研究与技术开发“九五”国家科技攻关及提高高研究开发投资强度的建议。     

基于遗传算法的工作辊温度场参数优化模型

针对热连轧机工作辊热辊形计算中温度场模型的热交换等参数难以确定的问题 ,建立了基于遗传算法的参数优化模型 ,可以解决复杂条件下的热参数的求解问题。利用优化参数计算的轧辊温度场与实际测量结果一致。     

ARCGIS环境下基于DEM的流域特征提取

研究选取位于陕西省延安城南12 km处的万花乡向阳沟小流域。采用1∶10000大比例尺的比例尺5 m分辨率的DEM作为基本的地形数据,应用ESR I公司开发的ARCG IS地理信息系统软件进行流域特征的提取。经分析得到了研究区域河网特征以及研究区其它常用的流域特征信息,与实际河流水系特征基本吻合,认为应用DEM划分的流域结果是合理的。     

A disposable sensor based on immobilization of acetylcholinesterase to multiwall carbon nanotube modified screen-printed electrode for determination of carbaryl

A simple method has been devised for immobilization of acetylcholinesterase (AChE) covalent bonding to a multiwall carbon nanotube (MWNT)-cross-linked cellulose acetate composite on a screen-printed carbon electrode (SPCE) and a sensitive and disposable amperometric sensor for rapid determination of carbaryl pesticide is proposed. The immobilized enzyme was preserved on this film because of the excellent biocompatibility and non-toxicity of cellulose acetate. Based on the inherent conductive properties of the MWNT, the immobilized AChE had greater affinity for ATCl and excellent catalytic effect in the hydrolysis of ATCl. MWNT improved the interface enzymatic hydrolysis reaction and increased the amperometric response of the sensor. Under optimum conditions, the inhibition of carbaryl on AChE increased linearly with the increasing concentration of carbaryl in two ranges, from 0.01 to 0.5 μg mL⁻¹ and from 2 to 20 μg mL⁻¹, with the correlation coefficients of 0.9985 and 0.9977, respectively. The detection limit was 0.004 μg mL⁻¹ taken as the concentration equivalent to 10% decrease in signal. The sensor showed acceptable stability, accuracy and could be fabricated in batches, thus it is economic and portable. This type of disposable enzyme-based amperometric sensor has extensive application potential in environmental monitoring of pesticides.     

Synthesis and characterization of a novel proton‐exchange membrane for fuel cells operating at high temperatures and low humidities

The synthesis of a p‐toluidine/formaldehyde (PTF) resin was performed, and the effects of the molar ratio of the individual monomers and the polymerization conditions on the structure of the PTF resin were studied. Fourier transform infrared and ¹³C‐NMR spectra were used to characterize the PTF. Wide‐angle X‐ray diffraction patterns revealed the crystalline structures of various PTFs. Polarized optical microscopy revealed that the molar ratio of the monomers had a strong effect on the crystalline morphologies. A longer polymerization time turned out a polymer with a higher intrinsic viscosity and molecular weight, which led to differences in the proton conductivity. All of the PTFs showed a higher proton conductivity than a commercial Nafion membrane at 90–100°C and 0% relative humidity. The proton conductivity of the PTF series could be improved by sulfonation with sulfuric acid and could be maintained after blending with polyurethane. Pure methanol could be used as a fuel source because of the insolubility and nonwetting properties of PTF in methanol to increase the output current density for a PTF membrane electrode assembly. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

氧气顶吹转炉吹炼过程动态模型

通过炉气流量和成分的在线采样信息，用积分法计算熔池排出碳量，并根据熔炼体系中碳的守恒，动态推算熔池含碳量，由此来预报吹炼终点。较深入研究了提高炉气流量检测精度的方法，如心平衡修正和钢液成分反馈修正等，并采用了滤波算法，这些措施有利于提高动态模型的精度。     

Modeling Multiterminal Spintronic Devices

We are encountering tremendous opportunities and challenges in combining emerging nanotechnology for developing nanoelectronic devices. Researchers are designing nanoelectronic circuits based on newly discovered nanoscale building blocks, such as spintronic devices. In this paper, we calculate conductance in spintronic gates using the nonequilibrium Green's function and show useful operations for "multiterminal" logic gates. These spintronic devices can be used to design complicated spin circuits     

EXPLO-500T型拖拉机式地震钻机

万程欣,EXPLO-500T型拖拉机式地震钻机．物探装备，2006，16（4）：314-316 EXPLO—500T型拖拉机式地震钻机采用大马力拖拉机底盘、全液压控制，结构紧凑、操作简单、可靠性强、钻井效率高，特别适合林带、丘陵地区施工。