全文获取类型
收费全文 | 82篇 |
免费 | 3篇 |
专业分类
化学工业 | 25篇 |
金属工艺 | 4篇 |
机械仪表 | 1篇 |
建筑科学 | 3篇 |
能源动力 | 1篇 |
轻工业 | 3篇 |
无线电 | 7篇 |
一般工业技术 | 18篇 |
冶金工业 | 16篇 |
自动化技术 | 7篇 |
出版年
2022年 | 5篇 |
2021年 | 4篇 |
2018年 | 2篇 |
2017年 | 3篇 |
2015年 | 2篇 |
2014年 | 3篇 |
2013年 | 5篇 |
2012年 | 5篇 |
2011年 | 4篇 |
2010年 | 5篇 |
2008年 | 8篇 |
2007年 | 2篇 |
2006年 | 4篇 |
2005年 | 2篇 |
2004年 | 2篇 |
2003年 | 1篇 |
2002年 | 1篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 3篇 |
1998年 | 5篇 |
1997年 | 1篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1988年 | 3篇 |
1980年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有85条查询结果,搜索用时 0 毫秒
1.
Anubhav Jain Ivano E. Castelli Geoffroy Hautier David H. Bailey Karsten W. Jacobsen 《Journal of Materials Science》2013,48(19):6519-6534
We examine the performance of genetic algorithms (GAs) in uncovering solar water light splitters over a space of almost 19,000 perovskite materials. The entire search space was previously calculated using density functional theory to determine solutions that fulfill constraints on stability, band gap, and band edge position. Here, we test over 2500 unique GA implementations in finding these solutions to determine whether GA can avoid the need for brute force search, and thereby enable larger chemical spaces to be screened within a given computational budget. We find that the best GAs tested offer almost a 6 times efficiency gain over random search, and are comparable to the performance of a search based on informed chemical rules. In addition, the GA is almost 10 times as efficient as random search in finding half the solutions within the search space. By employing chemical rules, the performance of the GA can be further improved to approximately 12–17 better than random search. We discuss the effect of population size, selection function, crossover function, mutation rate, fitness function, and elitism on the final result, finding that selection function and elitism are especially important to GA performance. In addition, we determine that parameters that perform well in finding solar water splitters can also be applied to discovering transparent photocorrosion shields. Our results indicate that coupling GAs to high-throughput density functional calculations presents a promising method to rapidly search large chemical spaces for technological materials. 相似文献
2.
Alla Popova Ghita Geoffroy Marie-France Renou-Gonnord Pascal Faucon Ellis Gartner 《Journal of the American Ceramic Society》2000,83(10):2556-2560
To better understand the mechanism of interaction between hydrating silicate-based cements and polymeric dispersants of the type used as superplasticizers in modern construction concretes, two different types of polymeric dispersant were added (at concentrations of 1 and 10 g/L) during the synthesis of calcium silicate hydrate (C-S-H) via the pozzolanic reaction in dilute slurries of lime and reactive silica, at Ca/Si ratios in the range of 0.66–1.50. Although both polymers gave degrees of adsorption of >79% in all cases studied, no significant structural modifications of the resulting C-S-H products were observed via X-ray diffraction or 29 Si magic angle spinning–nuclear magnetic resonance. These results differ from recent work in which it was shown that similar types of polymer could intercalate into the interlayers of C-S-H that was made using an alternative process. It is suggested that the process by which the C-S-H is formed may have a strong influence on whether C-S-H can intercalate polymers. This observation is relevant to understanding the fate of such polymers in concrete. 相似文献
3.
Robertson Shannon D.; Zelaznik Howard N.; Lantero Dawn A.; Bojczyk Kathryn Gadacz; Spencer Rebecca M.; Doffin Julie G.; Schneidt Tasha 《Canadian Metallurgical Quarterly》1999,25(5):1316
Three experiments were conducted to examine whether timing processes can be shared by continuous tapping and drawing tasks. In all 3 experiments, temporal precision in tapping was not related to temporal precision in continuous drawing. There were modest correlations among the tapping tasks, and there were significant correlations among the drawing tasks. In Experiment 3, the function relating timing variance to the square of the observed movement duration for tapping was different from that for drawing. The conclusions drawn were that timing is not an ability to be shared by a variety of tasks but instead that the temporal qualities of skilled movement are the result of the specific processes necessary to produce a trajectory. These results are consistent with the idea that timing is an emergent property of movement. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
4.
Alla Popova Ghita Geoffroy Ellis M. Gartner A. Lapp 《Journal of the American Ceramic Society》2002,85(5):1303-1305
Small-angle neutron scattering (SANS) was used to study calcium silicate hydrate (C-S-H) formed via pozzolanic reaction between calcium oxide and ultrafine silica in water or polymer solutions at a temperature of 20°C. The SANS profile of this product was consistent with a structure that consisted of platelets with maximum diameters of ∼20 nm (± 5 nm) in the x – y plane, which was similar to a structure that had been deduced in previous work via X-ray diffractometry. The presence of two different types of superplasticizer in solution (at a concentration of 10 g/L) had no significant effect on its formation kinetics or its SANS profile. 相似文献
5.
JM Tronchet L Brenas F Barbalat-Rey M Zsély M Geoffroy 《Canadian Metallurgical Quarterly》1998,17(6):1019-1031
Bicyclonucleosides bearing a 5-deoxy-5-N-hydroxyamino-3,N5-(1,1-ethano)-beta-D-furanosyl sugar moiety (15-18) have been prepared by glycosidation of the corresponding bicyclosugars obtained via an intramolecular reverse Cope elimination. The configuration of the asymmetric carbon of the 1,1-ethano bridge is the most important factor directing the conformation of the N-hydroxypyrrolidine ring and its invertomers ratio as shown by variable temperature H NMR experiments. 相似文献
6.
Recombinant human interleukin-1 alpha (rIL-1 alpha), at concentrations that were not growth-inhibitory when given alone (100-10,000 U/ml), enhanced the growth inhibition resulting from a 72-h fluorouracil (FUra) exposure in HCT116 colon cancer cells. Median-effect analysis of clonogenic assays indicated that rIL-1 alpha, given 24 h prior to and following a 24-h exposure to FUra, increased lethality in a more than additive fashion. rIL-1 alpha did not appear to significantly affect [3H]-FUra metabolism, total [3H]-FUra-RNA incorporation or RNA retention after drug removal, inhibition of thymidylate synthase, or thymidine triphosphate pool depletion. During continuous exposure to rIL-1 alpha, transient stimulation of RNA and DNA synthesis was observed at 72 h, with a return to normal by 96 h. A 24-h exposure to 10 microM FUra altered the elution profile of newly synthesized DNA as monitored by pH step alkaline elution. An accumulation of lower-MW single-stranded DNA species was noted with FUra compared to control, accompanied by a significantly decreased proportion of DNA retained on the polycarbonate filter: 10% retained vs. 32% for control (P = 0.01). A 48-h exposure to rIL-1 alpha alone did not affect the elution profile of nascent DNA species, nor did it enhance the effects of FUra. Although FUra did not appreciably affect pulse [3H]-uridine incorporation into RNA for the initial 8-24 h of FUra exposure, progressive inhibition of net RNA synthesis was observed thereafter. FUra prevented the stimulatory effect of rIL-1 alpha on RNA synthesis, and net RNA synthesis was significantly inhibited (by 64-79% after 72 and 96 h) with the combination compared to rIL-1 alpha alone. Continuous exposure to 10 microM thymidine did not rescue cells from the lethality of FUra alone or the combination of FUra plus rIL-1 alpha, suggesting that depletion of deoxythymidine triphosphate as a consequence of thymidylate synthase inhibition was not the most important component of FUra toxicity. In contrast, 1 mM uridine provided partial protection against the toxicity of FUra alone or with rIL-1 alpha. Although uridine did not affect FUra metabolism, it decreased FUra-RNA incorporation by 42-60%, presumably as a consequence of the 2-fold expansion of UTP pools. [125I]-rIL-1 alpha binding was nonspecific; with a 24-h exposure, however, internalized [125I]-rIL-1 alpha exceeded cell surface-bound material by 2-fold.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
7.
ML Hawkins JJ Wynn DC Schmacht RS Medeiros TR Gadacz 《Canadian Metallurgical Quarterly》1998,64(6):552-6; discussion 556-7
Changes in the management of trauma over the past few years are significantly affecting postgraduate surgical education, with the lack of operative trauma experience being a major concern in some programs. This problem is accentuated in residency programs that obtain their trauma caseload primarily from blunt injury. Our experience over the past 6 years confirms that the growing trend toward nonoperative management of blunt liver and spleen injuries in adults is likely to exacerbate this problem. Blunt trauma admissions to our Level I trauma center increased from 2888 from 1991 through 1993 (group A) to 3587 from 1994 through 1996 (group B). Liver and/or splenic injuries occurred with equal frequency in both groups. Whereas diagnostic peritoneal lavage was used in 26 per cent of group A, its use dropped to 2 per cent in group B as abdominal computerized tomography was used more frequently to evaluate these patients. Nonoperative management increased from 10 per cent of group A to 54 per cent of group B. As a result, therapeutic laparotomies dropped from 85 in group A (58% of patients with liver/splenic injuries) to 74 (35%) in group B and nontherapeutic laparotomies from 48 (33%) to 23 (11%). While the evolution in the management of blunt liver and splenic injuries has resulted in the avoidance of nontherapeutic laparotomies, the operative caseload available to surgical housestaff has been adversely affected. Although the Residency Review Committee has stressed the importance of the critical care management of these patients, the criteria used to evaluate the number of trauma cases in postgraduate surgical education may need to be revised. 相似文献
8.
Tobin S.P. Vernon S.M. Bajgar C. Haven V.E. Geoffroy L.M. Lillington D.R. 《Electron Device Letters, IEEE》1988,9(5):256-258
Tandem cells of GaAs grown by metalorganic chemical vapor deposition (MOCVD) on thin Ge to address both higher efficiency and reduced weight are discussed. GaAs/Ge monolithic tandem cells of 4-cm 2 area have been produced with independently verified efficiencies up to 21.7% (AM0, one sun, 25°C, total area). Under AM1.5 global conditions, efficiencies are up to 24.3%. These are believed to be the highest one-sun efficiencies reported for GaAs/Ge cells, and the highest efficiency for a two-terminal monolithic tandem cell 相似文献
9.
Thomas C. van den Ende Jeroen M. M. Heuts Dr. Geoffroy P. P. Gential Marten Visser Michel J. van de Graaff Dr. Nataschja I. Ho Prof. Dr. Wim Jiskoot Dr. A. Rob P. M. Valentijn Nico J. Meeuwenoord Prof. Dr. Herman S. Overkleeft Prof. Dr. Jeroen D. C. Codée Prof. Dr. Sjoerd H. van der Burg Dr. Els M. E. Verdegaal Prof. Dr. Gijsbert A. van der Marel Prof. Dr. Ferry Ossendorp Dr. Dmitri V. Filippov 《Chembiochem : a European journal of chemical biology》2021,22(7):1215-1222
Synthetic vaccines, based on antigenic peptides that comprise MHC−I and MHC-II T-cell epitopes expressed by tumors, show great promise for the immunotherapy of cancer. For optimal immunogenicity, the synthetic peptides (SPs) should be adjuvanted with suitable immunostimulatory additives. Previously, we have shown that improved immunogenicity in vivo is obtained with vaccine modalities in which an SP is covalently connected to an adjuvanting moiety, typically a ligand to Toll-like receptor 2 (TLR2). SPs were covalently attached to UPam, which is a derivative of the classic TLR2 ligand Pam3CysSK4. A disadvantage of the triply palmitoylated UPam is its high lipophilicity, which precludes universal adoption of this adjuvant for covalent modification of various antigenic peptides as it renders the synthetic vaccine insoluble in several cases. Here, we report a novel conjugatable TLR2 ligand, mini-UPam, which contains only one palmitoyl chain, rather than three, and therefore has less impact on the solubility and other physicochemical properties of a synthetic peptide. In this study, we used SPs that contain the clinically relevant neoepitopes identified in a melanoma patient who completely recovered after T-cell therapy. Homogeneous mini-UPam-SP conjugates have been prepared in good yields by stepwise solid-phase synthesis that employed a mini-UPam building block pre-prepared in solution and the standard set of Fmoc-amino acids. The immunogenicity of the novel mini-UPam-SP conjugates was demonstrated by using the cancer patient's T-cells. 相似文献
10.
C?té Sylvana M.; Borge Anne I.; Geoffroy Marie-Claude; Rutter Michael; Tremblay Richard E. 《Canadian Metallurgical Quarterly》2008,44(1):155
The authors examined the role of familial risk and child characteristics in the association between the type of child care in infancy (maternal care [MC]) versus nonmaternal care [NMC]) and emotional/behavioral difficulties at 4 years old. Canadian families (N=1,358) with children between 1 and 12 months old were followed over 4 years. Family risks were found to moderate the association between type of child care and physical aggression. MC in infancy was associated with lower levels of physical aggression among children from a low-risk family background but not among those from a high-risk family background. The effect size was small (d=-0.16; confidence interval [CI]=-0.3, -0.01). Family risk and the sex of the child moderated the association between child care and emotional problems. MC in infancy was associated with a lower level of emotional difficulties among girls from low-risk families but not among boys or among children from high-risk families. The effect size was moderate (d=-0.44; CI=-0.65, -0.23). The study indicates that the effect of child care type in infancy varies by family and child characteristics. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献