Preparation and properties of CuInS2 thin film prepared from electroplated precursor

Thin CuInS₂ films were prepared by sulfurization of Cu/In bi-layers. First, the precursor layer was electroplated onto the treated surface of Mo-coated glass. Observation of the cross-section prepared by focused ion beam (FIB) etching revealed that the void-free film was initially formed on the top surface of the precursor layer and continued to grow until the advancing front of the film reached the Mo layer. The nucleation of voids near the bottom of the CuInS₂ film followed. To determine whether the condition of the Cu/In alloy influences the CuInS₂ quality we investigated the Cu/In alloy state using FIB. We found that the annealed precursor of low Cu/In ratio (1.2) has several voids in the mid position in the layer compared with Cu-rich precursor (1.6). The cross-sectional view of the Cu-rich absorber layer is uniform compared with the low copper absorber layer. Thin film solar cells were fabricated using the CuInS₂ film (Cu/In ratio: 1.2) as an optical absorber layer. It was found that the optimization of a sulfurization period is important in order to improve the cell efficiency. We have not yet obtained good results with high Cu-rich absorber because of a blister problem. This blister was found before sulfurization. So, we are going to solve this blister problem before sulfurization.     

河道疏浚淤泥固化处理设备、流程及应用

河道疏浚中产生的淤泥如采取抛弃处理会造成资源浪费。介绍一种淤泥固化系统,可对城市污泥、淤泥、隧洞和建筑工程等产生的污泥在工地现场进行瞬间造粒后固化。以图示方式简单描述了淤泥投入、固化出料及养护的处理流程。根据强度试验结果,经系统固化后改良土的强度达到第3类工程用土。总结了淤泥固化系统具有体积小、高机动性、无副产物和处理数据自动记录等特点。介绍了该系统在日本应用的工程实例。最后指出,污泥固化处理成本取决于污泥特性、产物用途及环境指标等因素。     

Differences in Sterol Composition between Male and Female Gonads of Dominant Limpet Species

The present study demonstrated here for the first time that there are statistically significant differences in sterol composition between male and female gonads of the dominant limpets Cellana grata and Cellana toreuma, which are intertidal gastropods. Among 11 different sterols identified in this study, unusually high levels (11.2–19.8% of total sterols) of the Δ⁸-sterols 5α-cholest-8-en-3β-ol (zymostenol) and 5α-cholesta-8,24-dien-3β-ol (zymosterol), which have never been reported in aquatic invertebrate gonads, were present in only the male gonads.     

Self oscillation phenomena of turbulent jets in a channel

A new method based on the Coanda effect for self oscillation of a circular jet bounded by rectangular enclosure is suggested. The experiments in both air and water reveal regions of stable oscillation wherein relationships are obtained between the Strouhal number and the shape factor of the channel. This oscillation method can also be used to mix different liquids in a vessel. For such applications, an improvement of mixing by oscillation is shown by means of a residual concentration diagram for a salt solution.     

Simulation of high speed deformation of copper single crystals

Plastic deformation of copper single crystals was simulated by molecular dynamics using an embedded atom potential. The time step of molecular dynamics is on the order of 1 fs which corresponds to ultra high speed deformation. This paper reports the results of tension, bending, and compression tests. On notched tension surfaces, Heidenreich-Shockley partial dislocations formed near the tip of the notch as expected. In the absence of notch, creation of dislocations was quite difficult under tension. On compression surfaces, partial dislocations were generated near the wrinkle of the possibly redundant slip plane.     

Polymers degradable under environmental conditions through end-modification of poly(α-methylstyrene) derivatives

To induce degradabilities in polymers in response to environmental conditions, the end-modification reactions of poly(α-methylstyrene) derivatives were carried out. When diphenylphosphine chloride was used as a modifier for the living end of para-substituted PMS, the coupling efficiency was ca. 50%. 2-Phenylallyl halide derivatives such as 2-phenylallyl bromide, 2-(4-tolyl)allyl bromide, and α-trifluoromethylstyrene were found to be suitable end-modification agents. For example, ω-2-phenylallyl PMS was prepared with almost quantitative functionality by the reaction of the living PMS with 2-phenylallyl bromide. In a similar way, ω-3,3-difluoro-2-phenylallyl and ω-2-(4-tolyl)allyl PMS derivatives were synthesized. Based on thermogravimetric analysis, onset of the degradation temperature of the end-modified PMS derivatives decreased in the following order: ω-hydrogen- > ω-3,3-difluoro-2-phenylallyl- > ω-2-phenylallyl- > ω-2-(4-tolyl)allyl-PMS. Actually, the onset temperature of ω-2-(4-tolyl)allyl-PMS derivatives was 50°C lower than that of ω-H-PMS derivatives. These results indicate that the active species is produced effectively at the end unsaturated bond, which initiates the depolymerization of the polymer at rather low temperatures. Ionic degradation of these polymers was also investigated using butyllithium as an anionic initiator and methanesulfonic acid as a cationic initiator. Tendencies similar to the thermal degradation were observed. Therefore, it is concluded that a 2-phenylallyl substituent at the end of the PMS chain induces effective degradation through several mechanisms such as radical, anionic and cationic depolymerization reactions.     

Synthesis of KTiOPO4 (KTP) Thin Films Using Metallo-organics

Crack-free and highly transparent KTiOPO₄ (KTP) thin films were synthesized by the sol-gel method using a homogeneous precursor solution prepared from ("BuO)₂-P(O)(OH), Ti(OEt)₄, and KOEt in EtOH. Precipitated powders from the solution crystallized directly to KTP above 550°C. Polycrystalline KTP thin films were obtained at 600°C on various substrates. On NdAlO₃(100) substrates, KTP films with (101) and (240) preferred orientations were formed at 600°C. KTP films on glass substrates showed a refractive index of 1.75 and an absorption edge of 350 nm. KTP films exhibited the second harmonic generation of the 532 nm light on irradiaton with 1064 nm light.     

Energy analysis of a Kori-tofu plant

Consumption of energy was analysed on a Kori-tofu plant which processed 6 tons of soybeans per day, involving 13 operations such as wetmilling, extraction-denaturation of soy protein, coagulation, compression, freezing, thawing, drying and waste-water treatment. Total energy consumption per 1 kg of the dry Kori-tofu was 27·1 MJ of fuel energy (27·9 MJ of exergy) plus 8·3 MJ of electrical energy. Energy-intensive operations were the extraction-denaturation of soy protein and the drying for thermal energy, and the refrigeration and the waste-water treatment for electrical energy. The extraction-denaturation of soy protein consumed twice as much thermal energy as the drying. The waste-water treatment consumed more electrical energy than the whole manufacturing process. Points for energy conservation are discussed.