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101.
The mechanism of partial dispersion of uncoated flake graphite particles was investigated and compared with that of carbon microballoons (carbospheres) investigated earlier. Two types of flake graphite particles and the same base metals as previously used were investigated. The dispersive power of uncoated flake graphites was relatively small compared with that of spherical carbon balloons. For dispersion a temperature of 50 – 100 °C above the melting point with G = 1500 (where G is a non-dimensional gravity variable) is required with pure aluminium and its alloys. The variation in surface roughness of cast aluminium alloys containing flake graphites is due mainly to the magnitude of the centrifugal forces; the roughness decreases with increase in the acceleration (expressed in terms of G). The dispersive width of the graphitic layers and the clearance ratio are related; the width increases with ratio up to D/d = 2.5. 相似文献
102.
Effects of controlled-release coated urea (CRCU) on soil microbial biomass N in paddy fields examined by the 15N tracer technique 总被引:1,自引:0,他引:1
Kazuyuki Inubushi Solomon Acquaye Satoru Tsukagoshi Fujiyoshi Shibahara Shigeo Komatsu 《Nutrient Cycling in Agroecosystems》2002,63(2-3):291-300
Experiments were conducted in paddy fields at Shiga and Chiba Prefectures to study the effects of controlled-release coated urea (N-LP100) on soil microbial biomass and N uptake of rice plants by the 15N-tracer technique, during one cropping season. Three field fertilizer treatments (Zero N: 0 kgN ha–1, 15N-LP100: 64 kg N ha–1 and 15NH4Cl: 100 kg N ha–1) were set-up in the Shiga field experiment. After transplanting in the paddy fields at Shiga and Kashiwa (Chiba), a number of rice hills with standard growth were selected randomly and enclosed by polyacryl-plastic frames designated as microplots. 15N-LP100 (64 kg N ha–1) was applied in the Shiga and Kashiwa microplot experiments and the Shiga field experiment as deep-side placement (5 cm away from rice hill and 5 cm soil depth). Total N uptake of rice plants was analyzed in the course of plant growth. In addition, soils from the field fertilizer treatment plots and microplots (divided into 11 blocks) were taken and analyzed for microbial biomass N (BN) and biomass 15N (B15N). The results indicated that; (1) Plant N uptake from basal-applied fertilizers at the end of the study in the Shiga field experiment was 71.9 and 26.0% for 15N-LP100 and 15NH4Cl, respectively. In the Kashiwa microplot experiment, plant N uptake from applied 15N-LP100 was 51.2% at 67 days after transplanting (DAT) (2) Throughout the cropping season, BN was the highest, intermediate and the lowest for 15NH4Cl, 15N-LP100 and Zero N field experimental plots in the Shiga experiment, respectively. (3) In the micro-plot experiments, BN and B15N were generally higher in the soil block with deep-side application of 15N-LP100 compared with the other soil blocks. The deep-side placement of 15N-LP100 ensured a high efficiency of utilization of its N by rice plants. The method of 15N-LP100-placement also affected the spatial heterogeneity of microbial biomass N in the microplots. 相似文献
103.
The hydrogenation of benzene and methyl-benzenes was performed over a nickel catalyst supported on the porous glass prepared from borosilicate glass with an alumina content ranging from 3% to 5%. The micropore size of the porous glass decreased with increasing alumina content. Although the overall reaction rates of benzene and toluene did not significantly change with the alumina content in the borosilicate glass, the rate of 1,3,5-trimethylbenzene, which is the bulkiest molecule among the hydrocarbons tested, decreased as the content of the alumina in the support increased. This result indicates that a catalyst support with molecular shape selectivity can be prepared from borosilicate glass containing alumina. 相似文献
104.
An improved rapid procedure to determine the fatty acid composition of glycerolipids is described. The procedure includes
KOH-catalyzed transesterification and high-speed gas chromatography. Glycerolipids (20–40 mg) were mixed with 2 mL of hexane
and 0.2 mL of 2 M methanolic KOH at room temperature for 1–2 min. The fatty acid methyl esters in the hexane layer were analyzed
by gas chromatography on 10% SP-2340 at 240°C. Methyl linolenate and docosahexaenoate eluted within 2 and 5 min, respectively.
Analysis was thus completed with 5 min for common vegetable oils and 8 min for fish oils.
An erratum to this article is available at . 相似文献
105.
Double-bond localization in heneicosapentaenoic acid by a gas chromatography/mass spectrometry (GC/MS) method 总被引:1,自引:1,他引:1
Double-bond locations in heneicosapentaenoic acid from eel lipids were determined by a method involving gas chromatography/mass
spectrometry (GC/MS). The methyl esters of the pentaenoate fraction were first partially reduced with hydrazine. The resultingcis-monoenoates were then methylthiolated, and the resultant adducts were analyzed by GC/MS. The key fragmentation ions generated
by the cleavage between the methylthio-substituted carbons were used to ascertain the original double-bond positions in the
native fatty acid esters. Based on mass spectral evidence, the acid was identified as all-cis-6,9,12,15,18-heneicosapentaenoic acid. 相似文献
106.
Kohei Yamamoto Akira Shibahara Akiko Sakuma Takao Nakayama Goro Kajimoto 《Lipids》1990,25(10):602-605
The pulp lipids of jujube (Zizyphus jujuba var.inermis) fruit have been shown by chromatographic, spectrometric and chemical analyses to contain a series ofcis-monoenoic fatty acids with n−5 unsaturation as major acyl moieties. The total concentration of these n−5 fatty acids, such
as 14∶1n−5, 16∶1n−5 and 18∶1n−5, ranged from 22 to 54% of total fatty acids in the pulp lipids of 11 different sources. The
main component of the n−5 homologues was 16∶1n−5 in all cases. Other monoenoic acids with n−7 unsaturation, namely palmitoleic
(cis-9-hexadecenoic) acid andcis-vaccenic (cis-11-octadecenoic) acid, as well as with n−9 unsaturation, namely oleic acid, were also identified. In the seed lipids of jujube
fruit, none of the n−5 monoenoic acids could be detected. Thus the jujube pulp lipids are characterized by the predominance
of n−5 monoenoic acid isomers. 相似文献
107.
Tsuno M. Suga M. Tanaka M. Shibahara K. Miura-Mattausch M. Hirose M. 《Electron Devices, IEEE Transactions on》1999,46(7):1429-1434
A reliable method to determine the threshold voltage Vth for MOSFETs with gate length down to the sub-0.1 μm region is proposed. The method determines Vth by linear extrapolation of the transconductance gm to zero and is therefore named “GMLE method”. To understand the physical meaning of the method and to prove its reliability for different technologies 2-D simulation was applied. The results reveal that determined Vth values always meet the threshold condition, i.e., the onset of inversion layer buildup 相似文献
108.
Yuji Ohkubo Masafumi Shibahara Kento Ishihara Asahiro Nagatani Koji Honda Katsuyoshi Endo 《The Journal of Adhesion》2019,95(3):242-257
Although heat-assisted plasma treatment enables drastic improvement of the adhesion property of polytetrafluoroethylene (PTFE), plasma-treated PTFE does not strongly adhere to any adherend. To clarify which rubber compounding agents positively affect the adhesion strength of a plasma-treated PTFE/rubber assembly, six types of unvulcanised rubbers were prepared and thermally compressed to a plasma-treated PTFE sheet. Thus, it was found that SiO2 addition to rubber drastically increased the adhesion strength of a plasma-treated PTFE/rubber assembly and cohesion failure of rubber occurred with large fractions of SiO2 although no adhesives were used. To confirm the reaction between plasma-treated PTFE and SiO2 powder, X-ray photoelectron spectroscopy (XPS) measurements were performed for the thermally compressed SiO2/PTFE assembly after repeated washing. The XPS results indicated that hydrophilic SiO2 powder strongly adhered to the plasma-treated PTFE, whereas hydrophobic SiO2 powder did not adhere to the PTFE. In this paper, a model was proposed for a possible mechanism of strong adhesion of a PTFE/rubber assembly through both hydrogen and covalent bonds between silanol groups of the SiO2 powder surface in the rubber and hydroxyl or carboxyl groups on the plasma-treated PTFE. 相似文献
109.
Daiki Chiba Takeshi Yagi Mitsuaki Akiyama Toshiki Shibahara Tatsuya Mori Shigeki Goto 《International Journal of Information Security》2018,17(6):661-680
Domain names are at the base of today’s cyber-attacks. Attackers abuse the domain name system (DNS) to mystify their attack ecosystems; they systematically generate a huge volume of distinct domain names to make it infeasible for blacklisting approaches to keep up with newly generated malicious domain names. To solve this problem, we propose DomainProfiler for discovering malicious domain names that are likely to be abused in future. The key idea with our system is to exploit temporal variation patterns (TVPs) of domain names. The TVPs of domain names include information about how and when a domain name has been listed in legitimate/popular and/or malicious domain name lists. On the basis of this idea, our system actively collects historical DNS logs, analyzes their TVPs, and predicts whether a given domain name will be used for malicious purposes. Our evaluation revealed that DomainProfiler can predict malicious domain names 220 days beforehand with a true positive rate of 0.985. Moreover, we verified the effectiveness of our system in terms of the benefits from our TVPs and defense against cyber-attacks. 相似文献
110.