Stabilization of UV-curable vinyl compositions by transition metal compounds

A UV-curable composition, which has a shelf life of greater than six months at 60°C for bonding or coating glass surfaces, was developed. The formulation consists of a dimethacrylate monomer, a methacryltrialkoxysilane, a photoinitiator, MEHQ, DLTDP, a water scavenger, and FeCl₃. In the absence of FeCl₃, gelation occurs within 24 hr at 25°C. Gelation is caused by the formation of a crosslinked vinyl addition polymer having a methacrylate diester/silane monoester mole ratio of 20:3. Analogous stability is achieved if instead of FeCl₃ a number of heavy metal compounds are used, including CrCl₃, CoCl₂, NiCl₂, RuCl₃, Pr(fod)₃, and Eu(fod)₃. Nontransition metal compounds, e.g., AlCl₃, BCl₃, and SnCl₂, are poor or ineffective stabilizers. Gelation is initiated by free radicals. When MEHQ and DLTDP are present, less Fe³⁺ is converted to Fe²⁺ than in their absence. This indicates that a complex interaction is operating among these substances. A scheme is presented in which recycling of Fe³⁺ and phenolic and thioether antioxidants is proposed.     

Fine Tuned Nanolayered Metal/Metal Oxide Electrode for Semitransparent Colloidal Quantum Dot Solar Cells

Semitransparent photovoltaics have great potential, for example, in building‐integration or in portable electronics. However, the front and back contact electrodes significantly affect the light transmission and photovoltaic performance of the complete device. Herein, the use of a semitransparent nanolayered metal/metal oxide electrode for a semitransparent PbS colloidal quantum dot solar cell to increase the light transmission and power conversion efficiency is reported. The effect of the nanolayered electrode on the optical properties within the solar cells is studied and compared to a theoretically model to identify the origin of optical losses that lower the device transmission. The results show that the light transmission in the visible region and the photovoltaic performance are significantly enhanced with the nanolayered electrode. The solar cell shows an efficiency of 5.4% and average visible transmittance of 24.1%, which is an increase by 28.6% and 59.6%, respectively, compared to the device with a standard Au film as the electrode. These results demonstrate that the optical and electrical modification of transparent electrode is possible and essential for reducing the light reflection and absorption of the electrode in semitransparent photovoltaics, and, meanwhile the demonstrated nanolayered materials may provide an avenue for enhancing the device transparency and efficiency.     

Preparation of Fine Grained SiC Layer by Fluidized Bed Chemical Vapor Deposition with Pulsed Propylene

A novel strategy named pulsed propylene method was developed to prepare fine grained SiC layer. The SiC layer was uniformly coated on ceramic microspheres by fluidized bed chemical vapor deposition. Propylene was introduced into the deposition system in pulsed form at proper time intervals. By adjusting the propylene concentration and the pulse interval, the grain size of SiC can be controlled from micrometer scale to nanometer scale and the microstructure of the SiC layer changed from large columnar grains to fine equiaxed grains. The SiC layer with average grain size less than 300 nm was obtained with the pulsed propylene under a volume concentration of 5% at an injection time interval of 2 min. The as‐prepared fine grained SiC layer exhibited higher hardness and higher oxidation resistance than that of columnar grained SiC.     

Organic matter chlorination rates in different boreal soils: the role of soil organic matter content

Transformation of chloride (Cl(-)) to organic chlorine (Cl(org)) occurs naturally in soil but it is poorly understood how and why transformation rates vary among environments. There are still few measurements of chlorination rates in soils, even though formation of Cl(org) has been known for two decades. In the present study, we compare organic matter (OM) chlorination rates, measured by (36)Cl tracer experiments, in soils from eleven different locations (coniferous forest soils, pasture soils and agricultural soils) and discuss how various environmental factors effect chlorination. Chlorination rates were highest in the forest soils and strong correlations were seen with environmental variables such as soil OM content and Cl(-) concentration. Data presented support the hypothesis that OM levels give the framework for the soil chlorine cycling and that chlorination in more organic soils over time leads to a larger Cl(org) pool and in turn to a high internal supply of Cl(-) upon dechlorination. This provides unexpected indications that pore water Cl(-) levels may be controlled by supply from dechlorination processes and can explain why soil Cl(-) locally can be more closely related to soil OM content and the amount organically bound chlorine than to Cl(-) deposition.     

复合中空热管冷凝侧传热特性

复合中空热管能够有效解决普通重力热管换热设备的酸露点腐蚀问题,在回收低温烟气（<200℃）余热领域有重要的应用。建立了复合中空热管传热实验平台,对复合中空热管冷凝侧传热特性进行了实验研究。实验所用热管管长1080mm,不锈钢材质,工作介质为甲醇;热管蒸发侧和冷凝侧分别采用电加热和水冷却方式,K型热电偶被用于测量管壁温度和冷却水进出口温度,真空压力传感器测量管内蒸气饱和压力;研究了充液率（15%≤V+≤40%）和蒸发侧热流密度（9.48kW/m2≤q≤37.91kW/m2）对冷凝侧传热特性的影响。结果表明：当充液率为20%时,复合中空热管冷凝侧均温性能最好,冷凝侧换热系数最大,传热性能最佳;随着蒸发侧热流密度的增大,复合中空热管有效冷凝长度增大,冷凝侧换热系数增大。实验研究为工业应用提供了基础。     

Differential Expression of Peroxisomal Proteins in Distinct Types of Parotid Gland Tumors

Salivary gland cancers are rare but aggressive tumors that have poor prognosis and lack effective cure. Of those, parotid tumors constitute the majority. Functioning as metabolic machinery contributing to cellular redox balance, peroxisomes have emerged as crucial players in tumorigenesis. Studies on murine and human cells have examined the role of peroxisomes in carcinogenesis with conflicting results. These studies either examined the consequences of altered peroxisomal proliferators or compared their expression in healthy and neoplastic tissues. None, however, examined such differences exclusively in human parotid tissue or extended comparison to peroxisomal proteins and their associated gene expressions. Therefore, we examined differences in peroxisomal dynamics in parotid tumors of different morphologies. Using immunofluorescence and quantitative PCR, we compared the expression levels of key peroxisomal enzymes and proliferators in healthy and neoplastic parotid tissue samples. Three parotid tumor subtypes were examined: pleomorphic adenoma, mucoepidermoid carcinoma and acinic cell carcinoma. We observed higher expression of peroxisomal matrix proteins in neoplastic samples with exceptional down regulation of certain enzymes; however, the degree of expression varied between tumor subtypes. Our findings confirm previous experimental results on other organ tissues and suggest peroxisomes as possible therapeutic targets or markers in all or certain subtypes of parotid neoplasms.     

Short communication: Variation in the composition and properties of Swedish raw milk for ultra-high-temperature processing

The composition and properties of raw milk are of great importance for the quality and shelf life of the final dairy product, especially in products with a long shelf life [e.g., ultra-high-temperature (UHT)-treated milk]. The objective of this study was to investigate the compositional variation in raw milk samples before processing at the dairy plant. Moreover, we wanted to investigate the effect of the UHT process on this variation (i.e., if the same variation could be observed in the corresponding UHT milk). The quality traits analyzed included detailed milk composition, counts of total and psychrotrophic bacteria, proteolytic activity, and color, as well as predictive measures of stability (i.e., ethanol stability and heat coagulating time). Samples of raw milk and the corresponding produced UHT milk were collected and analyzed on a monthly basis during 1 yr. Principal component analysis was used to identify months showing similarities and differences with respect to total variation. In contrast to previous studies, we observed only small variations between months and no clear effect of season for the raw milk. For the UHT milk, July and the winter months (December, January, and February) tended to separate from the other months. Quality traits showing significant variation were only to some extent identical in raw milk and UHT-processed milk. A better understanding of the natural variation in raw milk quality will provide opportunities to improve the shelf life of UHT-treated milk products.     

光纤法测量气-固两相流中的固含率

基于光线照射到颗粒上会发生漫反射这一现象,制作了一种测量气 固两相流中固含率的单光纤探针。对于自由堆积的催化剂颗粒,信号强度随催化剂与探针末端距离的减少而增加。对于其他物体,信号强度随物体与光纤距离的减少先增加后降低,在约1 mm处有极大值。采用板状单摆考察光纤探针对运动物体响应的灵敏性和准确性,实验结果与计算结果一致。分别用压差法和光纤法测量流化床中的固含率并进行比较,固含率较高时,压差法与光纤法的固含率基本相当;受颗粒间遮挡的影响,当固含率较低时,光纤法测得的固含率偏高。提供了一种一定范围内气 固两相流固含率的在线测量方法及原理,丰富了多相流测量理论和实践体系。     

Growth and characterization of n-type InP/InGaAs quantum well infrared photodetectors for response at 8.93 µm

We present experimental results on the growth and characterization of n-type InGaAs/InP quantum-well intersubband photodetectors for use at 8.93 μm. High-quality InGaAs/InP multiple quantum wells were grown by gas source molecular beam expitaxy, and then characterized by double-crystal x-ray diffraction and cross-sectional transmission electron microscopy. Based upon the structural parameters determined by these methods, the photocurrent response spectra were simulated using a six-band effective bond-orbital model. The theoretical results are in excellent agreement with experimental data. Additional important device characteristics such as dark current, spectral response, and absolute responsivity are also presented.