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排序方式: 共有517条查询结果,搜索用时 12 毫秒
31.
Kakimoto Y Naetoko Y Hara H Miyatake M Sato A Tatsuguchi H Takahata R Yamamoto R Joh T 《Shokuhin eiseigaku zasshi. Journal of the Food Hygienic Society of Japan》2004,45(3):165-174
A collaborative study involving 8 laboratories was conducted to evaluate a method for the simultaneous determination of pesticide residues in 6 types of fruits and vegetables (spinach, tomato, apple, radish, cabbage and carrot). The method of analysis was the same as reported by Kakimoto et al. in 2003. One hundred and thirty-nine pesticides were spiked by each of 8 laboratories at levels of 0.1 microg/g (pesticides analyzed by GC/MS) or 0.5 microg/g (pesticides analyzed by HPLC) into the 6 kinds of samples. Statistical analysis showed that 111 pesticides could be analyzed with practical precision by this method. For screening purposes, the method could analyze 118 pesticides. The median values of the limits of detection were 0.001-0.041 microg/g. The calibration curves were linear in the range of 0.5-5 microg/mL for most pesticides with median correlation coefficients of 0.983-1.000. 相似文献
32.
Thermal Diffusion of Si Atoms at the Interface of Mo/Si Bilayers Studied with a Soft X-ray Emission Microscope 总被引:1,自引:1,他引:0
1 Introduction Thepropertyofthedeviceswithalayerstruc turesuchassuperlattices,multilayercoatings,andsemiconductordevicesisdependentuponthequali tyoftheinterfacebetweenadjacentlayers.Fromtheviewpointoftheirpracticalusage,thermalsta bilityoftheinterfaceis… 相似文献
33.
The authors have demonstrated photochemical deposition of aluminum oxides from Trimethylaluminum (TMA) and N2O by using a pulsed ArF excimer laser (193 nm). Both TMA and N2O are efficiently photodissociated by the 193 nm light. The films are grown on Si and InP wafers contained in a low pressure
flowing cell with a heated substrate. The incident laser beam is focused and parallel to the substrate surface. Typical deposition
rates are 80–150 A/min. Stripes of aluminum oxide 30 mm wide are uniformly grown on 7.5 cm Si-wafers. The film composition
and purity have been investigated using Auger and Infra-red spectroscopy analysis. Surprising results are the relatively low
concentration of carbon. Refractive index and thickness have been determined by an ellipsometer. Typical values for the films
are 1.54–1.62. Metal-oxide-semiconductor capacitors have been fabricated and characterized. The C-V curves for n-InP/aluminum
oxide have clockwise hysteresis, and minimum loop width is less than 0.5 V. The surface state densities are 1 × 1011 cm-2 eV−1 at the mid band gap. 相似文献
34.
Kosuke Nagaya Sadahiko Takeda Yoshitaka Nakata 《International journal for numerical methods in engineering》1986,23(6):1081-1099
This paper is concerned with the method for solving the vibration problem of coil springs of arbitrary shape. In the analysis the exact field transfer matrix is derived from the solution of the fundamental equation of the three-dimensional curved beam theory. The transfer matrix is given by combining this field transfer matrix and the point transfer matrix. The analysis derives the frequency equation which is applicable to coil springs of general shape. Numerical calculations have been carried out for hyperboloidal springs and barrel springs. Experimental tests also have been carried out to verify the present results. 相似文献
35.
Yuji Yabuki Yoshitaka Mukaida Yoshinori Saito Kazunori Oshima Tatsuo Takahashi Eiichi Muroi Kei Hashimoto Yasushi Uda 《Food chemistry》2010
To characterise the composition of sulphur-containing constituents in Chinese chive (Allium tuberosum Rottler), GC–MS and HPLC analyses were carried out, using 12 varieties of Chinese origin, 4 varieties of Japanese origin and 6 commercially available cultivars. Five disulphides (dimethyl, allyl methyl, methyl 1-(E)-propenyl, diallyl, and allyl 1-(E)-propenyl), two trisulphides (dimethyl and allyl methyl), and two vinyldithiins (3-vinyl-[4H]-1,2- and 2-vinyl-[4H]-1,3-) were identified on the basis of their mass spectral and GC-retention data. Among the detected sulphur compounds, sulphides with a methyl group predominated over those with an allyl group. This was supported by the HPLC estimations, suggesting that all cultivars examined had much greater amounts of methiin than alliin. Also, two novel compounds were tentatively identified as [3H,4H]-1,2-dithiin and [2H,4H]-1,3-dithiin on the basis of their mass spectral features, GC-retention data, and some experimental results on their formation in reaction mixtures with different proportions of methiin and alliin. Their formation mechanism was proposed. 相似文献
36.
Asabranchofsuperamolecularchem istry ,lanthanidecalixarenechemistryhasat tractedconsiderableresearchinterestforsever alyears[1~ 5 ] .Inthisrespect,Harrowfieldetal.[6~ 13] synthesizedalotoflanthanidecal ixarenecomplexes ,andrevealedtheircrystalstructures .Amongstt… 相似文献
37.
Iwaji Y. Sukegawa T. Okuyama T. Ikimi T. Shigyo M. Tobise M. 《Industry Applications, IEEE Transactions on》1999,35(3):606-612
In an asynchronous pulsewidth modulation (PWM) method, the ratio of the carrier frequency to the fundamental frequency must be at least 15-20 in order to suppress the beat phenomenon. However, it is impossible to achieve this condition for large-capacity inverters (e.g., gate-turn-off thyristor inverters), when the fundamental frequency is high. Assuming that the beat phenomenon is caused by an error generated in the PWM process, the authors have introduced a compensator to reduce the error. As a result, beat phenomenon can be decreased for a low carrier frequency. Effectiveness of the proposed method is shown by experimental results 相似文献
38.
Kenta Arima Katsuyoshi Endo Toshihiko Kataoka Kikuji Hirose Hidekazu Goto Yasushi Oshikane Haruyuki Inoue Yoshitaka Tatara Yuzo Mori 《Computational Materials Science》1999,14(1-4):236-240
Local density of states (LDOS) is obtained by the first principles calculation based on the density functional theory on the Si(0 0 1)2 × 1 surface and on the surface with an Al dimer. At an Al dimer, LDOS has a high intensity in the conduction band region, which cannot be seen on the Si(0 0 1)2 × 1 surface. This tendency is observed in STS measurements as well. The possibility for a microelementary analysis is presented by applying this method to other metal atoms on the Si surface. Furthermore, it is pointed out that STS measurements should be always performed at the same tip-sample separation to obtain reproducible STS spectrums. 相似文献
39.
Atsushi Ohma Tetsuya Mashio Kazuyuki Sato Hiroshi Iden Yoshitaka Ono Kei Sakai Ken Akizuki Satoshi Takaichi Kazuhiko Shinohara 《Electrochimica acta》2011,(28):10832
The biggest issue that must be addressed in promoting widespread use of fuel cell vehicles (FCVs) is to reduce the cost of the fuel cell system. Especially, it is of vital importance to reduce platinum (Pt) loading of catalyst layers (CLs) in the membrane electrode assembly (MEA) of a proton exchange membrane fuel cell (PEMFC). In order to lower the Pt loading of the MEA, mass transport of reactants related to the performance in high current density should be enhanced significantly as well as kinetics of the catalyst, which can result in the better Pt utilization and effectiveness. In this study, we summarized our analytical approach and methods for reduction of Pt loading in CLs. Microstructure, mass transport properties of the reactants, and their relation in CLs were elucidated by applying experimental analyses and computational methods. A simple CL model for I–V performance prediction was then established, where experimentally elucidated parameters of the microstructure and the properties in CLs were taken into account. Finally, we revealed the impact of lowering the Pt loading on the transport properties, polarization, and the I–V performance. 相似文献
40.
Nobuyoshi Ohno Sobahan Mia Kazuo Masuhara Kentaro Sonoda Yuji Yamashita Yoshitaka Tamura 《摩擦学汇刊》2013,56(5):722-730
The tribological properties of a new and unique thermoreversible gel lubricant (TR gel lube) were investigated. TR gel lube, which includes 10–40% of amide-type gelling agent in base fluid, is able to repeatedly alter or convert phase from gel state to liquid state at the melting point of the gelling agent. High-pressure rheological tests were performed in order to characterize the behavior of base oil and TR gel lube as a function of pressure and temperature. The effect of TR gel lube on ball bearing fatigue life was carried out by systematic tests using thrust ball bearings. The results of L 10 life tests of TR gel lube showed a longer life than the conventional greases. This result was investigated from the oil film formation. It was found that the gelling agent played a key role in the lubricating properties. Some mechanisms such as adsorbed film formation and solid-like formation are proposed. 相似文献