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排序方式: 共有318条查询结果,搜索用时 23 毫秒
31.
Nico Vieweg Mehmet Ali Celik Sabine Zakel Vineet Gupta Gernot Frenking Martin Koch 《Journal of Infrared, Millimeter and Terahertz Waves》2014,35(5):478-485
We present the first systematic study of cyanobiphenyls (CBs) and the phenylcyclohexanes in the range between 50 cm-1 (1.5 THz) and 500 cm-1 (15 THz). The impact of the alkyl chain length and of variations in the core structure on the spectrum is investigated using liquid crystals from the cyanobiphenyl and phenylcyclohexane families. Our measurements are supported by calculations based on density functional theory. This enables us to shine light on the vibrational dynamics of liquid crystal molecules in the terahertz frequency range. 相似文献
32.
Eight experiments examined the conditions under which a color singleton that is presented for the 1st time without prior announcement captures attention. The main hypothesis is that an unannounced singleton captures attention to the extent that it deviates from expectations. This hypothesis was tested within a visual-search paradigm in which set-size effects were used to infer attentional capture. The results showed that attentional capture by an unannounced color singleton was due to a mismatch with expectations concerning the color of the object and not due to its being a singleton. Thus, the results imply that theories of attention have to consider expectation discrepancy as a determinant of attention shifts. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
33.
SE Kim J Norfray WJ Heiser J Foran S Roychowdhury 《Canadian Metallurgical Quarterly》1994,13(5):405-407
In a 48-year-old Japanese man there was an uncontrollable and recurrent bleeding from a gastric ulcer and laparoscopic surgery was done. Two cannulae were placed in the gastric cavity through the abdominal wall and suture ligation of the bleeding vessel at the posterior wall of the stomach was done under video-visual control with endoscopic guidance. The bleeding ceased, complications were nil, and he remains well. This article reports on surgery done to repair uncontrollable, recurrent bleeding from a gastric ulcer. Two cannulae were placed in the gastric cavity through the abdominal wall and suture of the vessel at the posterior wall of the stomach was done with videovisual control and endoscopic guidance. This approach is concluded to have supplied minimal-access surgery, cost effectiveness, early discharge, less pain, and doctor-patient satisfaction. 相似文献
34.
35.
D. G. Konitzer K. W. Walters E. L. Heiser H. L. Fraser 《Metallurgical and Materials Transactions B》1984,15(1):149-153
A new technique, termed laser spin atomization, for the production of rapidly solidified prealloyed powders is described.
The results of experiments involving the production of powders of two alloys, one based on Ni, the other on Ti, are presented.
The powders have been characterized using light optical metallography, scanning electron microscopy, energy dispersive X-ray
spectroscopy, and Auger elec-tron spectroscopy, and these various observations are described. 相似文献
36.
Hans Harvig Gernot Kirchner Mats Hillert 《Metallurgical and Materials Transactions B》1972,3(1):329-332
The thermodynamics of ferrite containing dissolved copper is analyzed theoretically, taking into account the effect of copper
on the Curie temperature. By combination with experimental information on the solubility of copper in austenite, this model
is used to predict the solubility of copper in ferrite. The result shows good agreement with experimental data but indicates
that the data should be extrapolated in a manner different from that which has been previously suggested. The effects of copper
and cobalt on the relative stability of the α and γ phases in iron-rich alloys are compared. It is concluded that their difference
is mainly caused by the difference in their effects on the Curie temperature of α-iron. 相似文献
37.
David J. Heiser 《Color research and application》1981,6(4):237-243
This article presents a review of the present federal regulatory situation for a group of materials having particular interest for colorists: the cadmium sulfoselenide pigments. In recent years, use of cadmium has been subject to criticism based on adverse health effects. Accordingly, government has responded, as it has generally to human health and environmental concerns, with a proliferation of regulatory activity. Policies, programs, and rules of the FDA, EPA, and OSHA covering cadmium pigments are reviewed with respect to both current status and near-term future outlook. Although cadmiums have been and will continue to be caught up in a great many proposals for regulation, the actual level of rules in effect, at least up to the present, has been relatively modest. 相似文献
38.
S. McCoard A. Heiser K. Lowe A. Molenaar P. MacLean P. Johnstone S. Leath S.O. Hoskin M.A. Khan 《Journal of dairy science》2019,102(7):6076-6087
This study aimed to evaluate intake, body growth, and the development of the rumen, mammary gland, and immune system in Holstein Friesian calves reared for 100 d on the commercially available feed FiberStart (conserved alfalfa, Medicago sativa; Fiber Fresh Feeds Ltd., Reporoa, New Zealand) and fed calf milk replacer (CMR) for either 56 or 91 d. Eighty calves (40 bulls and 40 heifer calves) were reared indoors in groups (n = 5 of the same sex/pen). All calves were fed 4 L of CMR/d (175 g/L of CMR) in 2 feeds/d for the first 10 d and then 1 feed/d until d 49 or 84. The calves were gradually weaned by d 56 (earlier weaned; n = 8 pens) and d 91 (later weaned; n = 8 pens). All calves were fed FiberStart ad libitum as the only solid feed source from d 1 to 100 of the study. Irrespective of treatment, all calves had similar body weights at d 0 (40.9 ± 3.0 kg) and d 49 (74.2 ± 5.1 kg) of the study. Calf sex had no effect on intake, growth, blood, and immune system parameters. Earlier-weaned calves consumed 18% more solid feed dry matter but had 16% lower body weight gain (28.9 vs. 38.5 kg, respectively) from d 56 to 100 relative to later-weaned calves, resulting in different body weight at 100 d (104 vs. 121 ± 1.3 kg). Although earlier-weaned calves could compensate for the loss of CMR dry matter and crude protein intake from d 56 to 100 by increasing forage intake, they were unable to compensate for the loss of energy from the CMR by increasing solid feed consumption. Plasma β-hydroxybutyrate concentrations were 52% greater in earlier-weaned calves than in later-weaned calves at d 84, indicating greater metabolic activity of the rumen wall. The duration of CMR feeding had no influence on humoral or cell-mediated immune functions of the calves, as evidenced by a lack of effect on antivaccine antibody responses as well as on immune gene expression. Earlier- versus later-weaned heifer calves had 5% lower mammary gland mass, indicating that greater energy supply increased mammary mass. The results of this experiment demonstrate the ability to artificially rear dairy calves on a conserved alfalfa as the only solid feed. Furthermore, earlier weaning off CMR promotes solid feed intake and an associated increase in blood β-hydroxybutyrate, an indicator of rumen development, but increasing the duration of CMR feeding improves growth and mammary gland mass by d 100. The implications of these findings on lifetime growth, health, and milk production in dairy heifers warrant further investigation. 相似文献
39.
Sebastian Granitzer Raimund Widhalm Martin Forsthuber Isabella Ellinger Gernot Desoye Markus Hengstschlger Harald Zeisler Hans Salzer Claudia Gundacker 《International journal of molecular sciences》2021,22(4)
The placental barrier can protect the fetus from contact with harmful substances. The potent neurotoxin methylmercury (MeHg), however, is very efficiently transported across the placenta. Our previous data suggested that L-type amino acid transporter (LAT)1 is involved in placental MeHg uptake, accepting MeHg-L-cysteine conjugates as substrate due to structural similarity to methionine. The aim of the present study was to investigate the antioxidant defense of placental cells to MeHg exposure and the role of LAT1 in this response. When trophoblast-derived HTR-8/SVneo cells were LAT1 depleted by siRNA-mediated knockdown, they accumulated less MeHg. However, they were more susceptible to MeHg-induced toxicity. This was evidenced in decreased cell viability at a usually noncytotoxic concentration of 0.03 µM MeHg (~6 µg/L). Treatment with ≥0.3 µM MeHg increased cytotoxicity, apoptosis rate, and oxidative stress of HTR-8/SVneo cells. These effects were enhanced under LAT1 knockdown. Reduced cell number was seen when MeHg-exposed cells were cultured in medium low in cysteine, a constituent of the tripeptide glutathione (GSH). Because LAT1-deficient HTR-8/SVneo cells have lower GSH levels than control cells (independent of MeHg treatment), we conclude that LAT1 is essential for de novo synthesis of GSH, required to counteract oxidative stress. Genetic predisposition to decreased LAT1 function combined with MeHg exposure could increase the risk of placental damage. 相似文献
40.
Gernot Christoph 《Grundwasser》1997,2(4):167-175
The time and depth depending temperature distribution in an isolated expolratory hole in the dump of former open-cast lignite mine Cospuden is analyzed and interpreted. By means of hydrodynamical modeling several model assumptions are tested on following influences: seasons, hydraulic situation, geochemical processes, sampling regime, specific features of drilling, and support of bore hole. Best correspondence between measured temperature distribution and model assumptions is obtained by the following primary processes: seasonal influences of earth's surface and reactive processes in the dump. Then are favored: Slow exothermic reactions with an high extant of reaction heat in the depth of 2 to 6 m, slow strongly exothermic reactions above the piezometric water level in 9 to 13 m depth with a maximum near 11 m, and simultaneously run of fast endothermic and slow weakly exothermic reactions in the zone of saturation of the bore hole. It is tried to assign chemical reactions to these processes. 相似文献