全文获取类型
收费全文 | 56篇 |
免费 | 4篇 |
专业分类
化学 | 35篇 |
力学 | 2篇 |
数学 | 6篇 |
物理学 | 17篇 |
出版年
2023年 | 1篇 |
2021年 | 2篇 |
2020年 | 2篇 |
2017年 | 1篇 |
2016年 | 5篇 |
2015年 | 2篇 |
2014年 | 5篇 |
2013年 | 1篇 |
2012年 | 2篇 |
2011年 | 1篇 |
2010年 | 4篇 |
2009年 | 3篇 |
2007年 | 2篇 |
2003年 | 2篇 |
2000年 | 1篇 |
1994年 | 1篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 3篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1969年 | 1篇 |
1965年 | 1篇 |
1936年 | 1篇 |
1894年 | 1篇 |
1888年 | 2篇 |
1887年 | 1篇 |
1884年 | 1篇 |
排序方式: 共有60条查询结果,搜索用时 125 毫秒
1.
Devendra KC Deb Kumar Shah M. Shaheer Akhtar Mira Park Chong Yeal Kim O-Bong Yang Bishweshwar Pant 《Molecules (Basel, Switzerland)》2021,26(11)
This paper numerically explores the possibility of ultrathin layering and high efficiency of graphene as a back surface field (BSF) based on a CdTe solar cell by Personal computer one-dimensional (PC1D) simulation. CdTe solar cells have been characterized and studied by varying the carrier lifetime, doping concentration, thickness, and bandgap of the graphene layer. With simulation results, the highest short-circuit current (Isc = 2.09 A), power conversion efficiency (η = 15%), and quantum efficiency (QE~85%) were achieved at a carrier lifetime of 1 × 103 μs and a doping concentration of 1 × 1017 cm−3 of graphene as a BSF layer-based CdTe solar cell. The thickness of the graphene BSF layer (1 μm) was proven the ultrathin, optimal, and obtainable for the fabrication of high-performance CdTe solar cells, confirming the suitability of graphene material as a BSF. This simulation confirmed that a CdTe solar cell with the proposed graphene as the BSF layer might be highly efficient with optimized parameters for fabrication. 相似文献
2.
Shekhar KC Roshan K. Dhungana Namrata Khanal Ramesh Giri 《Angewandte Chemie (International ed. in English)》2020,59(21):8047-8051
We report a Ni‐catalyzed regioselective α‐carbonylalkylarylation of vinylarenes with α‐halocarbonyl compounds and arylzinc reagents. The reaction works with primary, secondary, and tertiary α‐halocarbonyl molecules, and electronically varied arylzinc reagents. The reaction generates γ,γ‐diarylcarbonyl derivatives with α‐secondary, tertiary, and quaternary carbon centers. The products can be readily converted to aryltetralones, including a precursor to Zoloft, an antidepressant drug. 相似文献
3.
Phenothiazine–BODIPY–Fullerene Triads as Photosynthetic Reaction Center Models: Substitution and Solvent Polarity Effects on Photoinduced Charge Separation and Recombination 下载免费PDF全文
Chandra B. KC Gary N. Lim Dr. Vladimir N. Nesterov Prof. Dr. Paul A. Karr Prof. Dr. Francis D'Souza 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(51):17100-17112
Novel photosynthetic reaction center model compounds of the type donor2–donor1–acceptor, composed of phenothiazine, BF2‐chelated dipyrromethene (BODIPY), and fullerene, respectively, have been newly synthesized using multistep synthetic methods. X‐ray structures of three of the phenothiazine‐BODIPY intermediate compounds have been solved to visualize the substitution effect caused by the phenothiazine on the BODIPY macrocycle. Optical absorption and emission, computational, and differential pulse voltammetry studies were systematically performed to establish the molecular integrity of the triads. The N‐substituted phenothiazine was found to be easier to oxidize by 60 mV compared to the C‐substituted analogue. The geometry and electronic structures were obtained by B3LYP/6‐31G(dp) calculations (for H, B, N, and O) and B3LYP/6‐31G(df) calculations (for S) in vacuum, followed by a single‐point calculation in benzonitrile utilizing the polarizable continuum model (PCM). The HOMO?1, HOMO, and LUMO were, respectively, on the BODIPY, phenothiazine and fullerene entities, which agreed well with the site of electron transfer determined from electrochemical studies. The energy‐level diagram deduced from these data helped in elucidating the mechanistic details of the photochemical events. Excitation of BODIPY resulted in ultrafast electron transfer to produce PTZ–BODIPY.+–C60.?; subsequent hole shift resulted in PTZ.+–BODIPY–C60.? charge‐separated species. The return of the charge‐separated species was found to be solvent dependent. In nonpolar solvents the PTZ.+–BODIPY–C60.? species populated the 3C60* prior to returning to the ground state, while in polar solvent no such process was observed due to relative positioning of the energy levels. The 1BODIPY* generated radical ion‐pair in these triads persisted for few nanoseconds due to electron transfer/hole‐shift mechanism. 相似文献
4.
5.
R. Benedikt F. Ulzer Focke Finkener Th. Morawski Alfred H. Allen O. Schweissinger R. Marzahn Dieterich Hazura F. W. A. Woll Bruno Röse Ch. Dubois L. Padé R. Bensemann Audoynaud Levallois T. Leone A. Longi F. Benecke Joseph Herz P. Soltsien C. Schädler C. L. Reimer W. Will und H. Hager 《Fresenius' Journal of Analytical Chemistry》1888,27(1):524-539
Ohne Zusammenfassung 相似文献
6.
7.
A multiobjective combinatorial optimization (MOCO) formulation for the following location-routing problem in healthcare management is given: For a mobile healthcare facility, a closed tour with stops selected from a given set of population nodes has to be found. Tours are evaluated according to three criteria: (i) An economic efficiency criterion related to the tour length, (ii) the criterion of average distances to the nearest tour stops corresponding to p-median location problem formulations, and (iii) a coverage criterion measuring the percentage of the population unable to reach a tour stop within a predefined maximum distance. Three algorithms to compute approximations to the set of Pareto-efficient solutions of the described MOCO problem are developed. The first uses the P-ACO technique, and the second and the third use the VEGA and the MOGA variant of multiobjective genetic algorithms, respectively. Computational experiments for the Thiès region in Senegal were carried out to evaluate the three approaches on real-world problem instances. 相似文献
8.
N. Bräuer B. Focke B. Lehmann K. Nishiyama D. Riegel 《Zeitschrift für Physik A Hadrons and Nuclei》1971,244(4):375-382
The γ-ray angular correlation of the 9/2+, 37 μs state in81Br and of the 181 keV, 120 μs state in78Br was disturbed by nuclear magnetic resonance. Theg-factors were determined to be ¦g¦=1.297±0.015 for the 37 μs level in81Br and ¦g¦=1.025±0.003 for the 120 μs state in78Br. 相似文献
9.
F. Dimmling N. Bräuer B. Focke T. Kornrumpf K. Nishiyama D. Riegel 《Zeitschrift für Physik A Hadrons and Nuclei》1974,271(2):103-105
The isomeric 731 keV, 11/2? state in113Sn was populated by the reaction113In(p, n). The halflife of the state was measured to be T1/2=89(3) ns and the magnetic moment was determined by means of the pulsed beam PAD method as μ=?1.293(22) n.m. 相似文献
10.
Beverly S Colley Melissa A Cavallin KC Biju David R Marks Debra A Fadool 《BMC neuroscience》2009,10(1):8