全文获取类型
收费全文 | 65篇 |
免费 | 3篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 2篇 |
综合类 | 1篇 |
化学工业 | 5篇 |
金属工艺 | 3篇 |
机械仪表 | 2篇 |
建筑科学 | 3篇 |
能源动力 | 4篇 |
轻工业 | 32篇 |
无线电 | 4篇 |
一般工业技术 | 7篇 |
自动化技术 | 6篇 |
出版年
2021年 | 2篇 |
2020年 | 1篇 |
2018年 | 3篇 |
2017年 | 2篇 |
2016年 | 1篇 |
2015年 | 2篇 |
2013年 | 10篇 |
2012年 | 4篇 |
2011年 | 3篇 |
2010年 | 1篇 |
2009年 | 5篇 |
2008年 | 7篇 |
2007年 | 3篇 |
2006年 | 3篇 |
2005年 | 2篇 |
2004年 | 3篇 |
2003年 | 1篇 |
2002年 | 1篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1986年 | 2篇 |
1982年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有69条查询结果,搜索用时 15 毫秒
11.
This work presents a theoretical study of two coherent schemes which allow the manipulation of wave packets created in atomic systems by strong ultrashort pulses. Our three-state system is composed of a ground state and two excited states simultaneously excited by the laser pulses. The corresponding dynamics are described in the bright state-dark state formalism where spectacular effects appear. (1) The wave packet created initially by a first pulse can be completely frozen through the action of a second strong pulse. (2) For pulses with a generalized pulse area equal to (2 p +1)2π (p integer), the population is preferentially transferred from the ground state to the dark state whatever the pulse duration. This is in complete disagreement with the physical interpretation valid in the weak field regime where the wave packet created by an ultrashort pulse is localized in the bright state at the end of the pulse. This effect can be revealed with wave packet interference induced by a second identical pulse. A simple analytical model using squared pulses is used to highlight the physical insight. This model is ‘reinforced’ by numerical simulations on the (4s–4p 2 P 1/2,1/3) transitions in potassium atoms excited with Gaussian pulses. 相似文献
12.
The effect of gamma radiation on aflatoxin production by Aspergillus flavus EA-81 in maize with different initial moisture levels was determined over a 15-day period. The viability of A. flavus on maize decreased over time with increasing moisture contents and storage at 8C. After 45 days at 28C, levels of viable conidiospores of A. flavus increased from 4.5 × 107 to about 3.0 × 108 per gram of maize. Levels of aflatoxin B1 produced by A. flavus were 10 μg kg-1 in the maize stored at 8C after 45 days. Production of aflatoxin was highest at 40% moisture and 28C. Irradiation of 1.0 or 2.0 kGy greatly reduced the level of mold growth relative to unirradiated controls. A dose of 4.0 kGy eliminated all viable fungi. Aflatoxin B1 production decreased with increased levels of irradiation and was negligible at 4.0 kGy. When maize was inoculated after irradiation and stored, the spore counts and aflatoxin levels were higher than in unirradiated and inoculated controls after 30 days. Apparently, the natural competitive microflora prevented growth and thus limited higher concentrations of aflatoxin in maize. 相似文献
13.
FAZLUR RAHMAN SHAMS TABREZ RAHAT ALI SAJJADUL KADIR AKAND MOHAMMED A. ALAIDAROUS MOHAMMED ALSAWEED BADER MOHAMMED ALSHEHRI SAEED BANAWAS ABDUR RUB ABDUL AZIZ BIN DUKHYIL 《Biocell》2021,45(6):1601-1610
Leishmaniasis is a vector-borne parasitic neglected tropical disease caused by a group of about 30 different
species of the genus Leishmania. It is transmitted by the bite of female phlebotomies sand fly. Three main clinical
manifestations of leishmaniasis include cutaneous, visceral, and mucocutaneous leishmaniasis. Visceral leishmaniasis
(VL) caused by Leishmania donovani, is an infection of reticuloendothelial system and fatal if untreated. Cholesterol,
a sterol that is prominent in the mammalian cell membranes whereas stigmasterol and ergosterol are more prevalent
in plants, yeast, and protozoa, respectively. Ergosterols which is absent in human being, is an important constituent of
parasite membrane. Sterol C-24 reductase (LdSR) enzyme catalyzes the final step in the ergosterol biosynthesis pathway.
The inhibition of biosynthesis of ergosterol may lead to decreased cell viability and growth. Here, we performed the
molecular docking-based virtual screening of a library of natural ligands against LdSR to identify a potential inhibitor to
fight leishmaniasis. Capsaicin, prenyletin, flavan-3-ol, resveratrol, and gingerol showed the top binding affinity towards
LdSR. Based upon ADME properties and bioactivity score, gingerol showed the best lead-likeness and drug-likeness
properties. Hence, we further annotated its leishmanicidal properties. We found that gingerol inhibited the growth and
proliferation of promastigotes as well as intra-macrophagic amastigotes. Gingerol exerted its antileishmanial action
through the induction of reactive oxygen species (ROS) in concentration-dependent manner. Gingerol induced ROS led
to apoptosis. Overall, this study described that gingerol would act as possible inhibitor to LdSR. 相似文献
14.
The defect structure and dielectric properties of BaTiO3 with 1 to 10 mol% Nd2 O3 additions were studied. The results indicated that neodymium occupies the barium site and charge compensation takes place by creation of titanium vacancies. The dependence of inverse electric susceptibility, spontaneous polarization, and specific heat on temperature for samples containing more than 2 mol% of Nd2 O3 were characteristic of a diffuse transformation resulting from a disordering of defects. The addition of Nd2O3 leads to a very drastic sfiift in the Curie temperature ( Tc ) of BaTiO3 ; 3 mel% Nd2 O3 addition moves Tc below room temperature. 相似文献
15.
16.
RIADH AL‐TAHIRI SHARAF OMAR ABDULLAH REWASHDEH 《International Journal of Dairy Technology》2008,61(4):347-351
The occurrence of bacteria from the genus Listeria in raw sheep milk and traditional local cheese was studied in three regions of the Karak district of Jordan. Conventional plating methods for the detection of Listeria species were followed to determine the average and the percentage of the contaminated samples. The result shows that there were significant differences between the regions in the study concerning the average and the percentage of positive occurrences of Listeria species in raw sheep milk. The results also showed that mainly L. monocytogenes and, to a lesser degree, L. ivanovii and L. innocua were found in the milk samples, while the occurrence of L. monocytogenes in cheese samples was very low. 相似文献
17.
The effect of γ-irradiation for controlling the production of aflatoxin B1 by Aspergillus flavus in ground beef stored at 5C for 2 weeks was investigated. Aspergillus, Penicillium, Cladosporium, Mucor, Scopulariopsis, Candida and Rhodotorula were the most common fungal genera contaminating ground beef. A. flavus and A. niger were the most common Aspergillus spp. Aspergillus flavus isolates were able to produce aflatoxin B1 in ground beef. Only 3 (20%) samples of ground beef were contaminated with aflatoxin B1 (25–45 μg/Kg). Gamma irradiation dose levels resulted in an immediate reduction in the total numbers of A. flavus. No growth or aflatoxin B1 production occurred at 1.50 kGy during storage. 相似文献
18.
This paper is concerned with the study of controllability of linear systems with delay in the control function. It has been illustrated that many of the techniques which proved to be useful in the study of linear systems with no delay (alman et al. 19G2, Kroindlcr and Sarachik 1964) can be generalized when dealing with systems having delay in the control. An explicit expression is given for transferring a given state to any desired state using minimum control energy. The corresponding conditions for linear time-invariant systems (ebakhy and Bayoumi 1971) are obtained as a special case. Extensions to multiple- delays systems are also included. A new degree of controllability is introduced and the corresponding criteria are obtained. 相似文献
19.
Laser peening and shot peening effects on fatigue life and surface roughness of friction stir welded 7075-T7351 aluminum 总被引:1,自引:0,他引:1
OMAR HATAMLEH JED LYONS ROYCE FORMAN 《Fatigue & Fracture of Engineering Materials & Structures》2007,30(2):115-130
The effects of laser peening, shot peening, and a combination of both on the fatigue life of Friction Stir Welds (FSW) was investigated. The fatigue samples consisted of dog bone specimens and the loading was applied in a direction perpendicular to the weld direction. Several laser peening (LP) conditions with different intensities, durations, and peening orders were tested in order to obtain the optimum peening parameters. The surface roughness resulting from various peening techniques was assessed and characterized. The results indicate a significant increase in fatigue life using LP compared to shot peening when tested on their native welded specimens. 相似文献
20.
ROBERTO?C. DANTEEmail author JOCHEN?LEHMANN OMAR?SOLORZA-FERIA 《Journal of Applied Electrochemistry》2005,35(3):327-337
A method to estimate the efficiency of a stack of several identical cells is described on the basis of the electrochemical behavior of a single cell. Efficiency of fuel cell stacks is defined by means of a combination of semi-empirical models of polarization curves and dimensionless variables such as reaction extent and utilization. The connection of flows among the cells is basically divided in two extreme cases and one intermediate case. Higher efficiencies are obtained when the same main flow (both anodic and cathodic) passes consecutively through the stack cells (Chain Flow), because it is favored thermodynamically. It is less favored when the main flow is strictly divided among all the cells (Separate Flow). In the intermediate case, the main flow is divided among all the stack cells and all the outlets are collected in one flow. The latter can spontaneously evolve to the more thermodynamically stable behavior of Chain Flow. 相似文献