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排序方式: 共有794条查询结果,搜索用时 15 毫秒
1.
N. A. Sivov A. I. Martynenko G. N. Bondarenko M. P. Filatova E. Yu. Kabanova N. I. Popova A. N. Sivov E. B. Kruts’ko 《Petroleum Chemistry》2006,46(1):41-59
Structures and compositions of the monomers guanidine acrylate and guanidine methacrylate, their homopolymers, and copolymers with diallyldimethylammonium chloride enriched in acrylate comonomer units were determined. It was shown that ampholytic copolymers, owing to their ionic nature, contained comonomeric guanidine acrylate or methacrylate units and diallyldimethylammonium chloride units, as well as the acrylate comonomer with the diallyl counterion and polymeric acrylate and diallyl ion pairs. It follows from IR and 1H NMR data that guanidine methacrylate has the same structure (with two hydrogen bonds) in the solid state and in solutions. Guanidine acrylate structures in the solid state and in dimethylsulfoxide are identical and analogous to guanidine methacrylate structure in this solvent. In water, the guanidine acrylate structure has another type of hydrogen bonding (with one hydrogen bond, where the proton is shifted toward the guanidine group). These features of hydrogen bonding of guanidine acrylate and guanidine methacrylate are also retained in their homopolymers and copolymers with diallyldimethylammonium chloride. It was shown that the thermal stability of the copolymers was higher than that of their homopolymers, confirming the formation of intramolecular ion pairs of oppositely charged units of ampholytic copolymers. Moreover, the thermal stability of guanidine methacrylate-diallyldimethylammonium chloride copolymers is higher than that of guanidine acrylate-diallyldimethylammonium chloride copolymers. 相似文献
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3.
YV Panchin YI Arshavsky TG Deliagina GN Orlovsky LB Popova AI Selverston 《Canadian Metallurgical Quarterly》1996,109(2):361-365
The locomotor activity in the marine mollusc Clione limacina has been found to be strongly excited by serotonergic mechanisms. In the present study putative serotonergic cerebropedal neurons were recorded simultaneously with pedal locomotor motoneurons and interneurons. Stimulation of serotonergic neurons produced acceleration of the locomotor rhythm and strengthening of motoneuron discharges. These effects were accompanied by depolarization of motoneurons, while depolarization of the generator interneurons was considerably lower (if it occurred at all). Effects of serotonin application on isolated locomotor and non-locomotor pedal neurons were studied. Serotonin (5 x 10(-7) to 1 x 10(-6) M) affected most pedal neurons. All locomotor neurons were excited by serotonin. This suggests that serotonergic command neurons exert direct influence on locomotor neurons. Effects of serotonin on nonlocomotor neurons were diverse, most neurons being inhibited by serotonin. Some effects of serotonin on locomotor neurons could not be reproduced by neuron depolarization. This suggests that, along with depolarization, serotonin modulates voltage-sensitive membrane properties of the neurons. As a result, serotonin promotes the endogenous rhythmical activity in neurons of the C. limacina locomotor central pattern generator. 相似文献
4.
R. G. Grebenshchikov V. F. Popova A. K. Shirvinskaya 《Glass Physics and Chemistry》2003,29(5):479-483
The phase equilibria in the LnAlO3–CaTiO3 (Ln = Dy, Y, Lu) systems are investigated and their phase diagrams are constructed for the first time. The thermal stability of the prepared solid solutions with a perovskite structure is studied. 相似文献
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6.
V. Z. Kutsova N. V. Popova A. G. Krimmel T. P. Chaikovskaya 《Metal Science and Heat Treatment》1992,34(11):704-707
Dnepropetrovsk Metallurgical Institute. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 11, pp. 31–33, November, 1992. 相似文献
7.
K Ivanov M Popova P Denev C Kratchanov 《Zeitschrift für Lebensmittel-Untersuchung und -Forschung》1992,195(5):455-458
Laboratory experiments have been carried out for the removal of heavy metals from hydrogenated vegetable oils using hydrated polyuronides (degree of swelling from 4 to 12.8 ml/g) such as alginic acid, pectic and pectinic acids. The effect of the type of polyuronide, degree of esterification and oil treatment on the degree of demetalization has been studied. It has been shown that with increase in the degree of esterification of the polyuronide the efficiency of demetalization decreases. The second and third treatment of the hydrogenated oil with pectinic acid resulted in a high degree of heavy metal removal. The possibility of efficient demetalization of hydrogenated oils by treatment with water solutions of pectinic acids has also been demonstrated. The degree of metal ion removal increases with decreasing concentration of pectinic acids in the water solution. 相似文献
8.
In order to determine the differences in histological grade of activity and the stage of fibrosis in patients with chronic liver diseases due to multiple hepatitis virus infection and single infection of HBV and HCV we assessed the 68 liver biopsies samples according to Knodell and Scheuer scoring systems. Retrospectively, 216 liver biopsies reports from consecutive patients with chronic viral hepatitis were analysed. Histological activity index (HAI) in HBV/HCV coinfection was higher than in a single HCV infection; it did not differ in groups of HBV/HBC and HBV. The difference was due to the interface hepatitis; lobular activity and portal inflammation were the same. In HDV superinfection HAI was high due to both portal-periportal and lobular hepatitis. HAI depended mainly upon the presence of HBV replication; in patients with chronic hepatitis C with HBV-DNA HAI was also higher than in single HCV group. No difference in HAI between triple and dual hepatitis virus infection was found. In patients with HBV/HCV coinfection and especially with HDV superinfection the advanced stages occurred more than often than in patients with single infections. 相似文献
9.
A. A. Nikitin O. V. Zausova N. V. Titova A. B. Shapovalov E. B. Vlasova L. A. Popova 《Glass and Ceramics》2007,64(9-10):373-374
The possibility of using the granulated form of biocompatible material made of calcium-phosphate glass ceramic BGC for treatment of maxillary cysts was demonstrated. 相似文献
10.
1. | Increasing the concentration of manganese to 1.0% in steel 10KhSND increases the ultimate strength without changing the yield point. |
2. | An increase in the ultimate strength and the yield point while maintaining the same levels of ductility can be achieved by adding 0.03–0.07% Ti to steel 10KhSND. In order to increase the strength of steel 10KhSND in the hot-rolled condition, we recommend the addition of Ti in amounts close to the maximum allowable according to State Standard 19282-73 (0.03%). |
3. | The increased strength of steel 10KhSND containing increased amounts of Ti of 0.025–0.030% occurs as a result of decreased grain boundary elongation and a decreased tendency toward grain growth. |