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71.
Biaoan Shan Li Cai Donald E. Hatfield Shuqin Tang 《Information Technology and Management》2014,15(2):99-108
Despite the fact that the resource-based view has drawn a great deal of attention in studying new ventures, our understanding on resource management in the emerging economies is limited and there are many unsolved issues. In this paper, theoretical reasoning approach is applied to analyze the relationship between the entrepreneurial resources and the organizational capabilities (including operating and dynamic capabilities) for new ventures. An empirical study in the context of emerging economy in China is conducted to verify the theoretical reasoning. As information technology becomes a key element for new ventures, the enterprise resources relevant to the network technology and e-commerce are especially focused, as well as the impact of information acquisition on the resource combination. The results from the theoretical and empirical study have shown that resource combination mediates the relationship of entrepreneurial resources and organizational capability. It is also found that the information acquisition affects the organizational capabilities significantly; however, there is an inverted U-shape relationship between the information acquisition and the resource combination in emerging economies . 相似文献
72.
Processing of Silicon Carbide-Mullite-Alumina Nanocomposites 总被引:2,自引:0,他引:2
Yoshio Sakka Donald D. Bidinger Ilhan A. Aksay 《Journal of the American Ceramic Society》1995,78(2):479-486
Nanocomposite materials in the form of nanometer-sized second-phase particles dispersed in a ceramic matrix have been shown to display enhanced mechanical properties. In spite of this potential, processing methodologies to produce these nanocomposites are not well established. In this paper, we describe a new method for processing SiC-mullite-Al2 O3 nanocomposites by the reaction sintering of green compacts prepared by colloidal consolidation of a mixture of SiC and Al2 O3 powders. In this method, the surface of the SiC particles was first oxidized to produce silicon oxide and to reduce the core of the SiC particles to nanometer size. Next, the surface silicon oxide was reacted with alumina to produce mullite. This process results in particles with two kinds of morphologies: nanometer-sized SiC particles that are distributed in the mullite phase and mullite whiskers in the SiC phase. Both particle types are immersed in an Al2 O3 matrix. 相似文献
73.
Lynnette S. Walsh Hentges Donald C. Beitz Norman L. Jacobson A. Dare McGilliard Jeffrey J. Veenhuizen 《Lipids》1985,20(11):735-742
In a 2×2 factorial arrangement, miniature pigs were fed four diets containing vegetable protein/fat (soybean) and animal protein
(egg white)/fat (beef tallow) to demonstrate the effects of protein and fat source on total plasma cholesterol, lipoprotein
distribution, low density lipoprotein (LDL) composition, and plasma clearance of LDL-cholesterol and protein. Beef tallow
consumption resulted in greater plasma cholesterol concentration, decreased LDL-cholesterol concentration, and a lower LDL-cholesterol
to LDL-protein ratio than did consumption of soybean oil. High density lipoprotein (HDL)-cholesterol concentration was increased
by beef tallow consumption. Cholesterol percentage by weight in LDL was significantly greater in pigs consuming soybean oil
than those consuming beef tallow. Percentages by weight of protein, triglyceride and phospholipid in LDL were not significantly
different in any group. Dietary protein source had no significant effect on total plasma cholesterol concentration, lipoprotein
concentration or LDL composition. Egg white consumption decreased fractional catabolic rate and irreversible loss of LDL-cholesterol
and LDL-protein when compared with consumption of soy protein. Dietary fat source had no consistent effect on LDL clearance
from plasma. Dietary fat and protein seemed to influence lipoprotein metabolism by different mechanisms. Fat source altered
lipoprotein concentration and LDL composition, whereas protein source affected the removal rate of LDL from plasma.
Data taken from a dissertation submitted to Iowa State University by L. S. Walsh Hentges as partial fulfillment of the requirements
for the Ph.D. degree. A preliminary paper, was presented at the meeting of the American Oil Chemists' Society in Dallas, Texas,
May, 1984. 相似文献
74.
子午线轮胎出现不久,就采用钢丝带束层代替了纤维带束层,这对于实现子午线轮胎提高使用寿命和改善操纵性能的潜能是必要的。 相似文献
75.
本文介绍了加工助剂莱茵塑分T和增塑剂A在全钢载重子午线轮胎胎面配方中的胶料性能对比,并着重考察了对胎面挤出性能和外胎性能的影响。试验结果表明,使用加工助剂能降低胎面的挤出温度,提高胎面的挤出速度;两种加工助剂相比,含莱茵塑分T的胶料老化性能、疲劳性能和分散性以及胎面挤出温度和断面气孔情况均比增塑剂A好;外胎的耐久试验均超过国家标准。 相似文献
76.
Two copolyimides, LARC-STPI and STPI-LARC-2, with flexible backbones were prepared and characterized as adhesives. The processability and adhesive properties were compared to those of a commercially available form of LARC-TPI.
Lap shear specimens were fabricated using adhesive tape prepared from each of the three polymers. Lap shear tests were performed at room temperature, 177°C, and 204°C before and after exposure to water-boil and to thermal aging at 204°C for up to 1000 hours.
The three adhesive systems possess exceptional lap shear strengths at room temperature and elevated temperatures both before and after thermal exposure. LARC-STPI, because of its high glass transition temperature provided high lap shear strengths up to 260°C. After water-boil, LARC-TPI exhibited the highest lap shear strengths at room temperature and 177°C, whereas the LARC-STPI retained a higher percentage of its original strength when tested at 204°C [68% versus 50% (STPI-LARC-2) and 40% (LARC-TPI)].
These flexible thermoplastic copolyimides show considerable potential as adhesives based on this study and because of the ease of preparation with low cost, commercially available materials. 相似文献
Lap shear specimens were fabricated using adhesive tape prepared from each of the three polymers. Lap shear tests were performed at room temperature, 177°C, and 204°C before and after exposure to water-boil and to thermal aging at 204°C for up to 1000 hours.
The three adhesive systems possess exceptional lap shear strengths at room temperature and elevated temperatures both before and after thermal exposure. LARC-STPI, because of its high glass transition temperature provided high lap shear strengths up to 260°C. After water-boil, LARC-TPI exhibited the highest lap shear strengths at room temperature and 177°C, whereas the LARC-STPI retained a higher percentage of its original strength when tested at 204°C [68% versus 50% (STPI-LARC-2) and 40% (LARC-TPI)].
These flexible thermoplastic copolyimides show considerable potential as adhesives based on this study and because of the ease of preparation with low cost, commercially available materials. 相似文献
77.
Geraniums (Pelargonium xhortorum Bailey) possess a pest-resistance mechanism, based on glandular trichomes and the exudate they produce, that has been shown to be effective against the two-spotted spider mite (Tetranychus urticae Koch). Using an intact plant bioassay, the effectiveness of the resistance mechanism was determined for another potential pest, the foxglove aphid (Acyrthosiphon solani Kaltenbach). Comparisons were made between plant lines previously analyzed for their degree of resistance to mites, as well as their glandular trichome density and trichome exudate production. Over 100 aphid adults were bioassayed on each of the five plant lines used in the experiment. In addition to adult aphid survival, the production and survival of nymphs was determined in this bioassay. The results indicate that plant lines that are resistant to the two-spotted spider mite are also resistant to the foxglove aphid, while lines susceptible to mites are susceptible to the aphids. To evaluate the physical impediment features of the trichome exudate, the behavior of foxglove aphid nymphs was compared on two geranium lines, one a resistant line with high trichome densities and large quantities of exudate and the second a susceptible line with few trichomes and reduced exudate. A third leaf surface type was produced by washing the exudate from resistant leaves using a mildly basic buffer solution prior to the bioassay. Aphid behavior was divided into five categories: feeding or probing, resting, wandering, struggling, and immobilized. On both susceptible leaves and resistant leaves from which the exudate had been removed by washing, the aphids settled quickly and were observed with inserted stylets during most of the observation intervals. In contrast, aphids on the unwashed resistant leaf surfaces often became ensnared in the sticky trichome exudate and had difficulty in settling to probe the leaf. Physical entrapment by glandular trichome exudate appears to be an important aspect of aphid resistance in geraniums. 相似文献
78.
Gudrún V. Skúladóttir Du Shi-Hua Ann E. Brodie Donald J. Reed Rosemary C. Wander 《Lipids》1994,29(5):351-357
Weanling male Sprague-Dawley rats were fed diets for four weeks which differed in their content of n−6 (corn oil; CO) and
n−3 fatty acids (fish oil; FO), but were similar in their content of saturated and monounsaturated fatty acids and vitamin
E. At the end of the four-week feeding period, each dietary group was subdivided into two groups. One group received a single
placebo injection of α-tocopherol-stripped corn oil (TSCO); the other group received a single injection of the free radical
generator, methyl ethyl ketone peroxide (MEKP), in TSCO. Twenty-four hours after injection, the effect of dietary oil and
MEKP treatment on endogenous lipid peroxide (LPO) production (measured as methylene blue formed by the “Determiner LPO” assay),
glutathione (GSH) and vitamin E content, and fatty acid composition of phosphatidylcholine and phosphatidylethanolamine in
heart and liver from unfasted animals were measured. FO-fed rats had significantly heavier hearts and livers, increased levels
of n−3 fatty acids in membrane phospholipids, and higher liver LPO levels than CO-fed rats. MEKP treatment resulted in significantly
lower body weights and liver GSH levels. The data indicate that dietary n−3 fatty acids increase lipid peroxidation in liver
somewhat more than in heart. The study also demonstrates that the effect of induced oxidative stress due to a single dose
of MEKP on lipid peroxide formation and antioxidant status in tissues from unfasted animals was independent of the dietary
oils. 相似文献
79.
Nathan S. Jacobson rew J. Eckel Ajay K. Misra Donald L. Humphrey 《Journal of the American Ceramic Society》1990,73(8):2330-2332
The reactions of a sintered α-SiC with 5% H2 /H2 O/Ar at 1300°C were studied. Thermomchemical modeling indicates that three reaction regions are expected, depending on the initial water vapor or equivalently oxygen content of the gas stream. A high oxygen content ( P (O2 ) > 10−22 atm) leads to a SiO2 formation. This generally forms as a protective film and limits consumption of the SiC (passive oxidation). An intermediate oxygen content (10−22 atm > P (O2 ) > 10−26 atm) leads to SiO and CO formation. These gaseous products can lead to rapid consumption of the SiC (active oxidation). Thermogravimetric studies in this intermediate region gave reaction rates which appear to be controlled by H2 O gas-phase transport to the sample and reacted microstructures showed extensive grain-boundary attack in this region. Finally, a very low oxygen content ( P (O2 ) < 10−26 atm) is thermochemically predicted to lead to selective removal of carbon and formation of free silicon. Experimentally low weight losses and iron silicides are observed in this region. The iron silicides are attributed to reaction of free silicon and iron impurities in the system. 相似文献
80.
Garrett BC Dixon DA Camaioni DM Chipman DM Johnson MA Jonah CD Kimmel GA Miller JH Rescigno TN Rossky PJ Xantheas SS Colson SD Laufer AH Ray D Barbara PF Bartels DM Becker KH Bowen KH Bradforth SE Carmichael I Coe JV Corrales LR Cowin JP Dupuis M Eisenthal KB Franz JA Gutowski MS Jordan KD Kay BD Laverne JA Lymar SV Madey TE McCurdy CW Meisel D Mukamel S Nilsson AR Orlando TM Petrik NG Pimblott SM Rustad JR Schenter GK Singer SJ Tokmakoff A Wang LS Wettig C Zwier TS 《Chemical reviews》2005,105(1):355-390