Comparative field study on precipitation, throughfall, stemflow, fog water, and atmospheric aerosol and gases at urban and rural sites in Japan

Precipitation collected by a wet-only sampler (WP), precipitation collected by a filtering-type bulk sampler (BP), throughfall (TF), stemflow (SF), fog water (FW), and atmospheric aerosol and gases were collected at two sites with different site classifications: an urban site (Mt. Rokko) and a rural site (Mt. Awaga) to investigate canopy-atmosphere interactions and to study the chemistry of precipitation in forested areas located in different atmospheric conditions. Compared to those at the rural site, the monthly volume-weighted pH values at the urban site were not significantly (p>0.05) different for WP, higher (p<0.05) for BP, not significantly (p> 0.05) different for TF, lower (p<0.01) for SF, and lower (p<0.01) for FW. The order of mean pH values at the urban site was FW相似文献   

Locational disadvantage of the hub

We show how spatial evolution is different between the two representative models of economic geography: [Krugman 99:483–499, 1991] and [Ottaviano et al. 43:409–436, 2002]. We analyze the impacts of falling transport costs on the spatial distribution of economic activities and welfare for a network economy consisting of three regions located on a line. It is normally considered that a hub city, i.e., a central region, always has locational advantage and manufacturing workers gain from trade. This is true in the former model, but not in the latter when markets are opened up to trade. This is because the price competition is so keen in the central region that the manufacturing sector moves to the peripheral regions, which aggravates the social welfare. We then show that when goods are close substitutes and share of manufacturing is of an intermediate level, the manufacturing activities completely disappear from the central region leading to a full agglomeration in one peripheral region.

An application of a homogenization method to the estimation of effective thermal conductivity of a hydrogen storage alloy bed considering variation of contact conditions between alloy particles

A homogenization method is applied to the estimation of effective thermal conductivity of a hydrogen storage alloy bed. By including the contact conditions between the alloy particles, the effect of contact conditions on the thermal conductivity is investigated.     

Substrate temperature dependence of electrical and structural properties of Ru films

Microstructures and resistivities of sputtered Ru films were investigated as a function of substrate temperature to obtain a single-layered Ru barrier without a Ta/TaN under layer. High resistivity Ru films with a high density of crevices, which enhances Cu diffusion along the crevices, were formed by the conventional sputtering process, i.e., sputtering at room temperature and annealing at 400 °C-700 °C for 30 min in Ar + 3%H₂. But, crevice-free and smooth Ru films with low resistivity, the same as that for the bulk phase, were formed when substrate temperature add sputtering was raised to 700 °C. Ru films formed by this process had (002) preferred orientation and then Cu (111) was formed by plating. This result corresponded to the tendency predicted by ab initio calculations.     

Influence of water and nitrogen deficit on fruit ripening and aroma potential of Vitis vinifera L cv Sauvignon blanc in field conditions

S‐Cysteine conjugate precursors of three volatile thiols were monitored in Vitis vinifera L cv Sauvignon blanc grapes during fruit ripening to assess the influence of vine water and nitrogen status on the grape aroma potential in field conditions. Four dry farmed plots were studied in the Pessac‐Léognan and Graves appellations (Bordeaux area) in 1998, which was a very dry vintage, and in 1999, when regular summer rainfall occurred. Soil water‐holding capacity ranged from very low to high. Soil total nitrogen content was related to soil organic matter content, which was highly variable on the four plots. Vine vigour was enhanced by both high water and nitrogen status. Major compounds in grapes depended mainly on vine water status. Water deficit‐stressed vines produced small berries with low sugar and low total acidity. Grape aroma potential was highest in vines under mild water deficit and moderate nitrogen supply. Severe water deficit stress seemed to limit aroma potential, as did nitrogen deficiency. Consequences for site selection and irrigation management for Sauvignon blanc are discussed. Copyright © 2004 Society of Chemical Industry     

Determination of 4-hydroxycoumarin rodenticides in animal products, fishery products, and honey by liquid chromatography-tandem mass spectrometry

A sensitive and selective method for the determination of 4-hydroxycoumarin-type rodenticides (warfarin, coumatetralyl, bromadiolone, and brodifacoum) in animal products, fishery products, and honey was developed. 4-Hydroxycoumarin rodenticides were extracted with acidified acetone, and the crude extract was purified by liquid-liquid partitioning followed by PSA column cleanup. Gradient liquid chromatographic separation was performed by using an Inertsil ODS-4 column, with methanol and water containing ammonium acetate as the mobile phase. Detection was carried out on a tandem mass spectrometer with electrospray ionization in the negative mode. Average recoveries from bovine muscle, bovine liver, bovine fat, swine muscle, salmon, eel, freshwater clam, egg, milk, and honey spiked at 0.0005-0.001 mg/kg were in the range of 79-108%, and the relative standard deviations were 2-8%. The limits of quantitations of the developed method were 0.0005 mg/kg for brodifacoum, 0.001 mg/kg for warfarin, coumatetralyl, and bromadiolone.     

超临界甲醇中PBT的分解行为研究

在超临界甲醇中考察了反应温度，反应压力对聚对苯二甲酸二丁酯（PBT）的分解及单体对苯二甲酸二甲酯（DMT）收率的影响，在此基础上对PBT熔点前后的反应速度常数进行了求解，PBT的分解效果以DMT单体的生成量评价，并采用气相色谱和凝胶色谱（GPC）对液相产物的组成进行分析。结果表明：随反应温度的增加，单体对苯二甲酸二甲酯的回收率增加，250℃，10min时可达92%；反应压力对PBT的分解几乎无影响；在PBT熔点以上，分解反应速度常数明显增大，分解反应速度显著提高；熔点以上进行反应时，分解产物中低聚物的分子量降低，单体收率增加。     

The Tensile Properties of an Fe-4 Pct Mo-0.2 Pct C Martensite Tempered under Applied Stress

In Fe-4 pct Mo-0.2 pct C martensite which is a typical secondary hardening steel, premature failure occurred in tensile test at 600 °C to 700 °C where solute atoms could diffuse easily. To clarify this phenomenon, the quenched specimens were tempered under applied stress and tensile-tested at room temperature. The following results were obtained: (1) Typical intergranular fracture was observed in specimens tempered in a temperature range of 600 °C to 650 °C with tempering times of five minutes to 10 minutes and applied stress (70 MPa to 140 MPa). (2) Based on Auger analysis, this phenomenon was considered to be caused by segregation of P, S, and Mo on prior austenite grain boundaries due to applied stress. (3) The direction of applied stress was found to be very significant. Namely, when the tensile direction was parallel to the applied stress during tempering, the specimen was more brittle, and when tensile direction was normal to the applied stress, the specimen was not so brittle. (4) To reduce this embrittlement, solution treatment temperature was adjusted, and it was found that the embrittlement was considerably reduced both in specimens with fine prior austenite grains and with some ferrite phase on prior austenite grain boundaries. Formerly with Kyoto University Formerly with Kyoto University This paper is based on a presentation made at the “Peter G. Winchell Symposium on Tempering of Steel” held at the Louisville Meeting of The Metallurgical Society of AIME, October 12-13, 1981, under the sponsorship of the TMS-AIME Ferrous Metallurgy and Heat Treatment Committees.     

Dynamic observations of welding phenomena and finite element analysis in high-frequency electric resistance welding

High-frequency electric resistance welding (hereinafter referred to as HFW) pipes and tubes are used for high-grade line pipes. To cope with the high need for weld seam reliability, the clarification of welding phenomena is important. To clarify the HFW phenomena, at first we developed a HFW simulation system by using electromagnetic, heat conductive and elastic plastic finite element analysis (FEA) methods. Continuous electromagnetic and heat conduction analysis was conducted by subdividing the cross section containing the electrode and the welding point into a large number of two-dimensional models. The temperature distribution in the HFW pipe welding procedure can be successfully simulated by this system. The deformation behaviour in which a portion of the weld rises to the inner and outer surfaces as the result of pressurization from welding rolls can be analysed with this system. Secondly, HFW phenomena have been visualized dynamically using a high-speed video camera technique. The high-intensity part visualized by high-speed images has good accordance with the temperature distribution of the FEA result. High-speed images have visualized the dynamic phenomena of molten metal flow and sputtering of molten steel. Very rapid movement of molten metal in the forming direction along the welding line was observed at the V-convergence point with a speed of 2–50 m s^?1, which was far faster than the welding speed. This rapidly moved molten metal generated the peculiar sputtering which spread the molten metal particles as describing an arc perpendicular to the welding line. These phenomena were assumed to be caused by the electromagnetic force concerning the molten steel at the V-convergence point.     

Determination method for ractopamine in swine and cattle tissues using LC/MS

Simple and reliable methods using LC/MS have been developed for the determination of the beta-agonist ractopamine in swine and cattle tissues. Ractopamine was extracted with ethyl acetate from muscle and liver, and the ethyl acetate layer was evaporated to dryness. The residue was purified by partition with acetonitrile/n-hexane. In the case of fat, ractopamine was extracted and purified by partition with acetonitrile/n-hexane. The resulting acetonitrile solutions were evaporated to dryness. The residue was dissolved in methanol, and subjected to LC/MS. The LC separation was performed on a Wakosil-II 3C18HG column (150 x 3 mm i.d.) in isocratic mode with 0.05% trifluoroacetic acid-acetonitrile (80:20) as a mobile phase at a flow rate of 0.4 mL/min. The MS detection was performed in the selected ion recording (SIR) mode, with detection of the M + H+ ion of ractopamine (m/z 302) produced by electrospray ionization (ESI). The mean recoveries of the drug from swine muscle (0.01 microg fortified), fat (0.01 microg fortified) and liver (0.04 microg/g fortified) were 99.7%, 99.5% and 100.8%, and those from cattle samples were 108.3%, 97.0% and 109.4%, respectively. The relative standard deviations (RSDs) ranged from 0.1% to 9.5%. The limit of quantification (LOQ) of the drug was 1 ng/g.