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排序方式: 共有43条查询结果,搜索用时 15 毫秒
1.
Studies have been made of the effect of Cd2+ on the oxidation rate of C3H8 in 80% H3PO4 at 130 C on platinized Pt electrodes.Dissolved Cd2+ discharges, probably as Cd0, and forms a stable sub-monolayer on a Pt electrode at potentials as high as 0·5 V versus RHE. Although this Cd0 layer is apparently substantially desorbed in favor of adsorbed hydrocarbon, C3H8 adsorption is inhibited in its presence. C3H8 oxidation is also inhibited. However, the C3H8 oxidation rate is observed to increase under some circumstances, and this appears to be because Cd isabsorbed into the Pt lattice. Co-plating of Cd and Pt leads to an electrode which, once the excess Cd has been removed, appears to be stable, and which catalyses C3H8 oxidation by about a factor of three at 0·25 V. Above 0·3 V, this absorbed Cd somewhat inhibits C3H8 oxidation.  相似文献   
2.
Renewable bioenergy could be supplied by high yielding grass crops, such as switchgrass (Panicum virgatum L.). Successful development of a bioenergy industry will depend on identifying cultivars with high yield potential and acceptable biofuel quality. The objective of this study was to evaluate 20 switchgrass populations in a field study planted in May 1997 in southern Iowa, USA. The populations included released cultivars and experimental germplasm of both upland and lowland ecotypes. Yield, plant height, stand, lodging, leaf:stem ratio, cell wall fiber, total plant nitrogen, and ash were determined on all entries between 1998 and 2001. Ultimate and proximate analyses together with chlorine and major oxide determinations were made on three cultivars in 2000 and 2001. Biomass yield was determined from a single autumn harvest each year. The lowland cultivars ‘Alamo’ and ‘Kanlow’ produced the most biomass, exceeding the production of the widely recommended upland cultivar ‘Cave-In-Rock’. Other traits differed among the cultivars, although the range was less than that for yield. The differences among years were substantially greater for the ultimate, proximate, and major oxide analyses than differences among cultivars. The highest yielding cultivars had low ash, slightly lower fiber concentrations, and moderate levels of important minerals, suggesting that excellent germplasm is available for biofuel production. The persistence of the lowland cultivars in southern Iowa may need more research because the winters during the experiment were mild.  相似文献   
3.
A model of pulmonary blastomycosis in the mouse, in which the portal of entry is the same as natural human infection, was used to study resistance to challenge after subcutaneous infection. One week after subcutaneous infection, mice were partially resistant to pulmonary challenge, and mice challenged two weeks after infection were resistant. Measurement of cellular and humoral immune responses to Blastomyces dermatitidis antigens after subcutaneous infection showed the following. (i) Delayed-type hypersensitivity appeared 1 week after infection, and responses increased for 3 weeks thereafter. (ii) Proliferative responses in vitro appeared in spleen cells at 1 week and in contralateral lymph node cells at 3 weeks, (iii) Serum antibody, detected by an enzyme-linked immunosorbent assay, appeared 1 week after infection and then increased in titer. (iv) Peritoneal macrophages were activated to inhibit replication of B. dermatitidis in vitro by the first week after infection. Prior subcutaneous infection also resulted in rapid clearing of a second subcutaneous challenge, as well as resistance to a lethal intraperitoneal challenge. This resistance was associated with the development of cell-mediated and humoral immune responses. These data provide a chronological framework for selective transfer experiments.  相似文献   
4.
<正>大米作为世界范围内的主要食物。但在碾白 和抛光过程中,许多有价值的营养物质因此损失。 现在一项新的布勒生产工艺可以使碎米转换成维 生素强化营养米粒。此开发合作伙伴为帝斯曼营 养产品部(DSM Nutritional Products),罗氏维生 素公司(Rochc Vitamins Ltd.)前身。  相似文献   
5.
A technique is presented for automatic detection of the longitudinal fissure in tomographic scans of the brain. The technique utilizes the planar nature of the fissure and is a three-dimensional variant of the Hough transform principle. Algorithmic and computational aspects of the technique are discussed. Results and performance on coronal and transaxial magnetic resonance data show that the algorithm is robust with respect to variations in image contrast in the data and to slight anatomic anomalies. A crucial resolution requirement in the data for accurate parameter estimations is a sufficient number of slices covering the whole brain. The Sobel magnitude edge operator, used for preprocessing, proved adequate for magnetic resonance scans with positive and negative brain/cerebrospinal fluid contrast.  相似文献   
6.
Waste gasses containing volatile organic compounds (VOC) are arising mainly form industrial production in which organic materials are processed. These VOC must be treated to levels so that they meet the local applicable legislation limits. Momentive specialty chemicals is a company which produces acrylic acid, acrylic acid esters, and acrylate polymers in Sokolov (Czech Republic). A mixed waste stream which contains 6,000–10,000 mg TOC/Nm3 of VOC is treated. The management would like to lower the operating costs of the thermal incineration unit used. It seems suitable in this case to replace the existing incinerator with a catalytic oxidation unit with use of a Pt–Pd/Al2O3 catalyst for VOC abatement. A full-scale unit was designed according to the waste gas composition and flow. Mass and energy balances were carried out, and it was discovered that the catalytic bed must be divided into two parts to prevent the reactor overheating and irreversible damage to the catalyst. A pilot plant was designed and implemented due to the potential threat of catalyst fouling by solid impurities and to confirm the expected conversion of VOC and CO. It also proves the long-term reliability of the catalytic reactor. The performed pilot tests confirmed that catalytic oxidation is suitable for the disposal of waste gas from acrylic acid and acrylates production (for this application and treated inlet concentration of VOC). VOC and CO removal efficiencies during pilot trials were 98.3 and 98.5 %, respectively.  相似文献   
7.
The instability of emulsions is basically clarified by a phase separation. The separated phase can either cream or sediment. Destabilization is mostly compounded by coalescence and gives a first indication through extension of droplets. In the cosmetics industry as well as many other branches of industry such as the food industry and paint and coatings industry, product stability is one of the most important quality criteria. Many stability tests have already been performed with the widest variety of methods from different fields of technology. In research and development it is especially important to obtain quick results on the stability of a formulation. Such results represent a tool that can help developers find an optimal formulation in a short time. In addition, they can shorten development times, leading to quicker introduction of a product in the market. Moreover, they can help to reduce storage stability tests to minimum, making less climatized rooms, space and work required to predict shelf-lives. The cycle test is an example of such a method developed in the field of rheology [1]. In this test the sample is subjected to continuously changing temperatures and its behavior observed. However, other methods can also conceivably used to predict stabilities. The aim of this work is to find a new model to predict the long-term stability. This model should be based on empirical data and it should determine the applicability of the time temperature superposition (TTS) principle to emulsions.  相似文献   
8.
Clean Technologies and Environmental Policy - Catalytic oxidation of volatile organic compounds (VOCs) is a widely used method for VOC emissions mitigation essential for the long-term...  相似文献   
9.
Kilkens TO  Honig A  Maes M  Lousberg R  Brummer RJ 《Lipids》2004,39(5):425-431
Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder with a high co-occurrence with affective dysregulation. Affective disorders have been associated with specific changes in the PUFA and cholesterol profile. In IBS, similar changes may be present as have been reported in patients with affective disorders. This exploratory study investigates (i) the level of affective dysregulation (AD) in IBS patients and healthy controls; (ii) PUFA and cholesterol profiles in IBS patients compared with controls; and (iii) associations between PUFA and cholesterol parameters with the level of AD. Blood samples were obtained for determination of the FA composition of plasma phospholipids and serum cholesterol in 23 diarrheapredominant IBS patients and 23 healthy matched controls. AD was scored using the Symptom Check List depression scale, the Hospital Anxiety and Depression Scale, and the Hamilton Depression Rating Scale. The level of AD was higher in IBS patients compared with controls. PUFA and cholesterol profiles did not differ significantly between groups. Total n−3 PUFA and cholesterol were significantly negatively associated and the ratio of n−6 to n−3 PUFA and the ratio of arachidonic acid to EPA were significantly positively associated with the level of AD. The findings of the present study reveal that AD was higher in IBS patients compared with healthy controls and that changes in PUFA and cholesterol profiles were significantly associated with the level of AD. These results warrant further studies regarding the role of PUFA and cholesterol status in the co-occurrence of AD and functional gastrointestinal disorders.  相似文献   
10.
The weather research and forecasting (WRF) model and the maximum likelihood ensemble filter (MLEF) data assimilation approach are used to examine the potential impact of observations from the future Geostationary Operational Environmental Satellite, generation R (GOES-R) on improving our knowledge about clouds. Synthetic radiances are assimilated from the 10.35 μm channel of the GOES-R advanced baseline imager (ABI) employing a ‘non-identical twins’ experimental setup. The experimental results are examined for an extratropical cyclone named Kyrill that produced unusually strong winds, widespread damage and fatalities in Western Europe in January 2007. The data assimilation problem is especially challenging for this case, as there is a large error in the model-simulated radiances resulting from incorrect cloud location. Although this problem is difficult to eliminate, data assimilation results indicate the potential of GOES-R data to significantly reduce these errors.  相似文献   
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