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101.
In order to improve the low temperature ductility and high temperature strength ofMoSi2 while keeping its superior high temperature oxidation resistance, the present work attempts to combine MoSi2with the C40 type disilicides of transition metals including Cr, V, Nb, Ta and Ti. The possibility of producing a thermally compatible composite of MoSi2 and the C40 disilicides is discussed by critical assessment of MoSi2-TSi2(T=Cr, V,Nb,Ta, Ti) pseudo-binary phase diagrams. Relative phase stability between the CIIb MoSi2 and the C40 TSi2 is investigated and lamellar MoSi2/TSi2 two-phase microstructures are obtained by appropriate choice of composition and heat-treament. Preliminary result on the microhardness of MoSi2/TSi2two-phase alloys is also discussed.  相似文献   
102.
In order to study the relationship between physical fitness/sport-specific skills and sports injuries 136 physical education students were studied during their 4-years of training in a prospective investigation. Physical fitness was measured every year using a battery of fitness tests, and the performance marks of a number of sports scored at the exams of the academy were used as parameters for the sport-specific skills. Sports injuries were recorded every 3 weeks on standard forms. Relative risk ratios were calculated between the tertile groups good, average and poor for all variables of physical fitness and sport-specific skills. Injury-proneness was defined for all and for acute and chronic injuries separately near the median number of injuries sustained. In only 6 out of 126 computed relative risks was a significant difference found. Discriminant analysis revealed an explanation of 16%, 14% and 11% of the variance for respectively all, acute and chronic injuries, at which 5 or 6 variables in varying combination were included. From our findings it may be concluded that physical fitness and sport-specific skills have little impact on sports injuries for the following two main reasons. Firstly, subjects at risk for sports injuries participate per definition in sports activities and have consequently developed their fitness and skills compared to the sedentary population. Thus, the range in physical fitness or sports skills in the population at risk is relatively small (physical education students belong to the 7th-10th decile in fitness test scores within a general college student population) and therefore an effect is hard to show. Secondly, the total number of sports injuries is very small and moreover, it should be distributed over several categories for analysis. The favourable advantages of using physical education students to study intrinsic risk factors (comparable and varied sports program, excellent compliance) appeared to be insufficient to compensate for drawbacks of selection.  相似文献   
103.
The catalytic steam gasification of four different coals using potassium and sodium carbonates as catalysts was carried out in a semi-flow type fixed-bed reactor. The coal was gasified with or without the catalyst under a steam—argon atmosphere at a heating rate of 50°C/s at 700–800°C. The catalytic activity of carbonates for gasification was remarkable for Japanese high-volatile coals (Miike and Takashima coals), and moderate for Australian medium-volatile coal (New Lithgow coal); however, the carbonates had little effect on gasification of Japanese lignite (Taiheiyo coal). It is assumed that Miike and Takashima coals soften and melt during the heating process to make the contact between char and catalyst better. New Lithgow and Taiheiyo coals do not have this property. Gasification was promoted significantly at lower temperatures when the catalyst was used. In both catalyzed and uncatalyzed runs the main products were hydrogen and carbon dioxide; the reaction temperature did not affect the composition of the gases much. A water—gas shift reaction occurred during gasification resulting in a large amount of carbon dioxide under a large excess of steam flow.  相似文献   
104.
FRIENDS (Flexible, Reliable and Intelligent ENergy Delivery System) is a new concept for a future power delivery system in which so‐called QCC (Quality Control Center) plays an important role to realize the customized power quality services and to connect a large number of distributed generators to distribution systems. In FRIENDS, QCCs are connected as a network through distribution cables to realize a reliable power supply. In this paper, a method to find the optimal network configuration of FRIENDS is proposed. The method can minimize the sum of facility installation cost and operational cost (distribution loss) under the constraint that the expected power interruption cost is less than a predetermined endurable value. The solution algorithm is based on tabu search, and employs a sensitivity analysis to select efficient facilities to be installed or to eliminate constraint violations. In the algorithm, single and double faults of power distribution system are taken into account to calculate the power supply reliability or expected power interruption cost. Several numerical real‐world examples are shown to demonstrate the validity of the algorithm. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 156(3): 32–40, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20264  相似文献   
105.
The Proximity between the central business district and the settlement has led to many changes in the local Bantik community. These include changes in the function of settlements, population size, location of residence, and the movement of local culture. This study aims to examine the spatial changes that occur in local neighborhoods with a focus on the Bantik tribal community in Malalayang. Data were obtained from a series of field observations, questionnaires and structured interviews. This study conducted a series of analyses on spatial patterns, sociocultural factors and urban policy. The results show that the dynamic changes are natural and hard to avoid, since they are related to the community's needs and development of the city. In order to face the changes, adjustments in the values of the local community towards the settlement terms and conditions are necessary. In addition, an increase in internal resources for those local communities is needed.  相似文献   
106.
著: 《风景园林》2019,26(10):35-39
了解环境并对我们熟悉的环境产生兴趣,对于察知环境问题并采取恰当的行动非常重要。本文涉及作者以往参与的几个研究实例,介绍关于身边自然环境和农作物的知识、认知、经验。在对花草游憩活动的调查中表明,人们使用植物进行的活动逐渐减少。对于外来植物的调查显示,许多人无法识别外来植物。在一项父母对于蔬菜的态度和经验的调查中表明,能够自发栽种蔬菜的人并不多,而父母对蔬菜的经验和意识可能会影响他们的孩子。基于上述结果得出,自然体验活动需要成年人提供适当的支持,并且有必要在家庭和社区中增加成年人的参与机会。  相似文献   
107.
This study calculated the carbon (C) input to farmland soils in Japan in an effort to investigate the potential increase in soil C of farmland soils by proper application of crop residues (straw and root) and manure. The calculation was based on inventory and activity data obtained from statistics, literature sources and inquiry reports for the year 2005. The total C resources from crop residues and manure in Japan were 6.1 Tg C year−1 and 2.3 Tg C year−1, of which 4.9 Tg C year−1 and 1.9 Tg C year−1, respectively, were applied to farmland soil. The average C application rate was 1.7 ± 1.6 Mg C ha farmland−1 year−1 and the proportion of manure was 23 ± 26%. One scenario that improved the allocation of manure and crop residue input to farmland soil increased the average C input to farmland soil to 1.8 ± 1.3 Mg C ha farmland−1 year−1. This agricultural C flow represented only a small percentage of the global warming potential of the whole of Japan. Thus, management of C resources in the agricultural sector should focus on the sustainable use of soil rather than the C sequestration potential of soil. To improve the C flow for areas with high C input, the transportation of manure to neighboring municipalities failed to reduce the excessive amount of manure since those areas are concentrated in only a few regions. Other measures were required to reduce environmental problems due to the over-supply of manure to farmland soils. For areas with low C input, the introduction of green manure, changes in cultivation methods, and land use type itself must be considered in relation to the individual C requirements specific to land use, soil type and climate conditions.  相似文献   
108.
Summary Possibility of living metathesis polymerization by Mo catalysts was examined for (p-n-butyl-o,o,m,m-tetrafluorophenyl)acetylene, which has two fluorine atoms at both ortho positions. The MoOCl4-n-Bu4Sn-EtOH (1:1:1) catalyst yielded a polymer with narrow molecular weight distribution ( ), but the corresponding MoCl5-based catalyst did not formed such a polymer. With the former catalyst, the number-average molecular weight of polymer increased in direct proportion to monomer conversion, while the molecular weight distribution remained narrow; this proves the livingness of the polymerization. The optimal conditions for the living polymerization were [n-Bu4Sn]/[MoOCl4]=∼1.0, [EtOH]/[MoOCl4]=0.5–1.5, and temperature≤30 °C. n-Butyl acetate and acetone as well as EtOH were effective as third catalyst components.  相似文献   
109.
The effect of different chemical compositions on the microwave dielectric properties of Ba(Zn1/3Ta2/3)O3xCaTiO3 and xMgTiO3yCaTiO3z(Nd2O3,wTiO2) was studied. High fQ dielectrics were designed by optimizing composition and firing conditions. Adding up to 1 mol % CaTiO3 to Ba(Zn1/3Ta2/3)O3 increased εr from 25 to 30 at a firing temperature of 1450 °C, and produced very high fQ values of more than 100 000 GHz at a firing temperature of 1550 °C. EPMA and XRD suggested that ceramics based on Ba(Zn1/3Ta2/3)O3 with CaTiO3 had mixed phases of Ba(Zn1/3Ta2/3)O3 and Ca–Ti–Zn–O. Addition of CaTiO3 increased the Ba(Zn1/3Ta2/3)O3 peak observed in XRD and decreased the Ba3Ta2O8 peak. Prolonged sintering of Ba(Zn1/3Ta2/3)O3 with CaTiO3 increased the fQ value but kept εr constant. 0.5MgTiO3–0.5CaTiO3z(Nd2O3,wTiO2) showed a high dielectric constant εr>40 and fQ>20 000 GHz. When w=1, τf decreased linearly with z around 0 ppm/ °C in 0.5MgTiO3–0.5CaTiO3z(Nd2O3,TiO2) (0.25≤z≤0.5). X-ray and EDX analysis revealed a mixed phase matrix of MgTiO3 and (Ca1?αNd2α/3)TiβO3. It was concluded that εr of the high fQ materials Ba(Zn1/3Ta2/3)O3xCaTiO3 and xMgTiO3yCaTiO3z(Nd2O3,wTiO2) would be increased by varying their chemical compositions, x, y, z, and w, and that their fQ value would be improved by appropriate choices of heating temperature and time.  相似文献   
110.
BACKGROUND: Studies have shown that nitric oxide (NO) and NO synthase (NOS) inhibitors injure and protect organs after endotoxin (lipopolysaccharide [LPS]) challenge. OBJECTIVE: To test the hypothesis that LPS-induced gut injury and bacterial translocation (BT) are mediated through activation of inducible NOS (iNOS). DESIGN: A randomized, controlled study using genetically altered, iNOS gene knockout mice. SETTING: University research laboratory. METHODS: Forty-five wild-type (iNOS+/+) or homozygous mutant (iNOS-/-) mice weighing 25 to 35 g were challenged with Escherichia coli LPS or saline (10 mg/ kg) intraperitoneally (n = 8/group). In a second set of experiments, a bacterial overgrowth model of BT (E coli monoassociation) was tested (n = 6-7/group). The mesenteric lymph nodes and cecums were cultured, and liver, ileal, and blood nitrite and nitrate levels measured 24 hours after LPS or E coli monoassociation. RESULTS: After LPS challenge, 87.5% of the iNOS+/+ mice but 0% of the iNOS-/- mice had BT to their mesenteric lymph nodes (P < .01; chi 2 analysis). Nitrite and nitrate levels of the liver, ileum, and blood were higher in the iNOS+/+ mice (P < .05). In the E coli overgrowth model, BT to mesenteric lymph nodes occurred in 100% of iNOS-/- and iNOS+/+ mice. CONCLUSIONS: In this limited study, LPS-induced BT did not occur in iNOS-deficient mice, suggesting that LPS induction of increased iNOS activity is necessary for LPS-induced BT to occur. In contrast, iNOS activation does not seem to be necessary in a bacterial overgrowth model of BT.  相似文献   
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