远程分布式光纤温度传感系统的设计和制造

为了测量长距离大范围空间分布温度场,设计制造出30km远程光纤温度传感器。基于光纤放大的反斯托克斯背向拉曼自发散射测温原理,对系统进行了优化设计。用1550nm掺铒光纤激光器作为抽运源,采用高速瞬态波形采样技术,累加平均等信号处理技术,解决了远处背向反斯托克斯弱信号的检测问题。采用了智能化恒温技术,使主要元器件在恒温条件下工作,解决了工程应用中环境的适应性。远程分布光纤拉曼温度传感器系统已达到的主要技术指标如下:光纤长度31km,测温范围0-100℃(可扩展),温度测量不确定度为±2℃,温度分辨力为0.1℃,测量时间为432s,空间分辨力为4m。     

青霉素发酵过程的模型仿真与补料优化

补料分批式青霉素发酵的机理模型已得到深入研究,但是模型往往难以用于补料的优化和批次内的控制。为了对模型进行优化控制,针对Birol等提出的青霉素发酵非结构动力学模型,合理调整了温度和pH变化的影响,得到了青霉素发酵过程的简化机理模型。反应基质的补料是青霉素优化控制的关键,选择对补料速率进行优化来提高青霉素的产量。由于机理模型具有非线性和约束条件,采用序贯二次规划算法来进行求解,其中将补料轨线进行分段处理提高了优化效率。优化计算结果表明改进的补料过程可以提高青霉素的浓度和产量。     

面向GIS基于专有名词优先的中文分词方法

提出了一种面向地理信息系统领域的基于专有名词优先的中文分词方法：利用专业词典、通用词典和同义词词典相结合的词典机制,优先切分专有名词,对粗分结果利用Trigram模型进行消歧而获取最终结果。实验证明,该分词算法对专业文献的分词处理具有较好速度和准确性。     

Effect of process parameters on electrical, optical properties of IZO films produced by inclination opposite target type DC magnetron sputtering

IZO films were deposited onto PET substrate at room temperature with the inclined opposite target type DC magnetron sputtering equipment, in which a sintered oxide IZO target (doped with 10% ZnO, packing density of 99.99%) was used. The effects of total sputtering pressure and film thickness on IZO films properties were studied. All the films produced at room temperature have a amorphous structure, irrespective of the total sputtering pressure and film thickness. A resistivity of the order of 10⁻⁴ Ω·cm was obtained for IZO films deposited at lower pressure (film thickness of 190 nm). The resistivity of IZO films deposited at room temperature depends on film thickness and shows a minimum at a thickness of 530 nm.     

Effects of TiN film coating on electrochemical behaviors of nanotube formed Ti-xHf alloys

Ti-xHf (x=10%, 20%, 30% and 40%, mass fraction) alloys were prepared by arc melting, and the microstructure was controlled for 24 h at 1 000 °C in argon atmosphere. The formation of nanotube was conducted by anodizing on Ti-Hf alloys in 1.0 mol/L H₃PO₄ electrolytes with small amounts of NaF at room temperature. And then TiN coatings were coated by DC-sputtering on the anodized surface. Microstructures and nanotube morphology of the alloys were examined by field emission scanning electron microscopy(FE-SEM) and X-ray diffractometry(XRD). The corrosion properties of the specimens were examined through potentiodynamic test (potential range from −1 500 to 2 000 mV) in 0.9 % NaCl solution by potentiostat. The microstructure shows the acicular phase and α′ phase with Hf content. The amorphous oxide surface is transformed to crystalline anatase phase. TiN coated nanotube surface has a good corrosion resistance.     

Electrodeposited Ni,Fe,Co and Cu single and multilayer nanowire arrays on anodic aluminum oxide template

The Ni, Fe, Co and Cu single and multilayer nanowire arrays to make perpendicular magnetic recording media were fabricated with nanoporous anodic aluminum oxide (AAO) templates from Watt solution and additives by the DC electrodeposition. The results show that the diameters of Ni, Fe, Co and Cu single and multilayer nanowires in AAO templates are 40–80 nm and the lengths are about 30 μm with the aspect ratio of 350–750. The magnetic properties of the prepared nanowires are different under different electrodepositing conditions. The remanences (B_r) of Ni/Cu/Fe multilayer nanowires are lower than those of others multilayer nanowires, and coercivity (H_c) of Ni/Cu/Fe multilayer nanowires are lower than those of others multilayer nanowires. These are compatible with the required conditions of high density magnetic media devices that should have the low coercivity to easily success magnetization and high remanence to keep magnetization after removal of magnetic field.     

Effect of second non-singular term of mode I near the tip of a V-notched crack

The effect of a second non-singular term of mode I in the vicinity of the tip of a V-notched crack is discussed. The undetermined eigenvector coefficients of singular and non-singular terms of eigenfunction expansion were calculated by the numerical analysis method using the reciprocal work contour integral method (RWCIM) based on Betti's reciprocal work theorem and finite-element analysis. This study demonstrates that the second non-singular term of mode I can have a significant effect on the size and shape of plastic zones as an additional fracture mechanics parameter along with the conventional parameter K .     

Cu enrichment behavior at steel-scale interface during high temperature oxidation of Cu containing steel

In order to suppress the surface cracking induced by Cu during reheating and hot rolling process,Cu enrichment and its migration at the steel-scale interface was investigated during heating of steel cast at temperatures between 1000℃and 1200℃in N₂-O₂ and N₇-H₂O atmospheres.For oxidation of Cu containing steel,Cu enriched phase was formed by the preferential oxidation of Fe and the enrichment and migration behavior of Cu depends on the oxidation temperature,steel chemistry and atmosphere condition.Ni in steel induced the formation of solid Cu and Ni enriched phase at steel/scale interface and in scale layer and the formation of uneven steel/scale interface, which suppresses the Cu enrichment because of extrusion of Cu enriched region before the formation of liquid phase.On the other hand,Sn addition promotes the liquid Cu formation at steel/scale interface and penetration into grain boundary of Cu enriched phase by decreasing solidus temperature and solubility limit.In addition,for oxidation at 1 200℃,the behavior of Cu at and around the steel-scale interface was found dependent to a large extent on morphology of the oxide scale formed during oxidation.At the early stage of oxidation,Cu-rich phase formed and accumulated at the steel scale interface under both O₂-N₂ and H₂O-N₂ atmospheres.As the oxidation proceeded,however,Cu enrichment at and its migration from the steel-scale interface were vastly different for different oxidizing atmospheres.In the case of O₂-N₂ oxidation,an oxide layer formed initially at the steel surface, but soon after a gap was developed at the steel-scale interface and grew in its size,which practically separated the scale from the steel substrate.The scale layer formed under this condition was porous.The Cu-rich phase initially formed at the interface was found migrating to the scale layer,leaving no Cu-rich phase at the interface.In the case of H₂O-N₂ oxidation,however,the scale layer formed was dense and tightly attached to the steel surface,and the Cu rich-phase continued to accumulate at the interface.Regarding the behavior of Cu-rich phase formed at the interface,it is proposed with experimental evidences that,when a gap forms at the steel-scale interface,it is the vaporization of Cu in the Cu-rich phase through the gap that brings Cu to the scale.     

冰结构蛋白对湿面筋蛋白冻藏稳定性的影响

研究冬小麦冰结构蛋白(ISP)对湿面筋蛋白冻藏稳定性的影响。采用差示扫描量热仪、动态流变仪、扫描电子显微镜分别研究空白湿面筋蛋白(未添加ISP)和添加ISP 的湿面筋蛋白冻藏不同时间后可冻结水含量、流变学特性及超微结构的变化。结果表明：1)随着冻藏时间延长,湿面筋蛋白可冻结水含量逐渐增大;冻藏时间相同时,添加ISP 湿面筋蛋白的融化焓小于空白湿面筋蛋白。2)湿面筋蛋白的弹性模量、黏性模量和蠕变均随冻藏时间的延长而降低;冻藏时间相同时,含ISP 湿面筋蛋白的蠕变明显小于空白湿面筋蛋白的相应参数。3)湿面筋蛋白网络经过冻藏后,不规则的孔洞更大,引入ISP 后,冰晶形成的不规则孔洞相对于空白湿面筋蛋白更加细小和均匀。说明ISP 能够通过减少湿面筋蛋白体系中的可冻结水含量,抑制冰晶形成和重结晶,从而减小冻藏过程中湿面筋蛋白网络遭受的破坏。