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1.
依据水利水电施工相关技术规范和安全法规,提出水利水电工程施工重大危险源辨析矩阵法。该方法首先利用LEC法对水利施工过程中的危险源进行初步判定,再用AHP法结合专家评定法对初定的危险源进行量化分析,得出综合安全指数,以此判定某项施工过程或作业是否是重大危险源。最后,利用该方法对大岗山水电站压力管道施工的危险性进行分析。 相似文献
2.
用AB腐蚀液对SI GaAs晶片进行AB微缺陷显示 (AB微缺陷密度AB EPD :10 3~ 10 4 cm- 2 量级 ) ,用KOH腐蚀液显示位错 (位错密度EPD :10 4cm- 2 量级 ) ,发现衬底上的位错对器件跨导没有明显的影响 ,而用AB腐蚀液显示的AB微缺陷对器件性能及均匀性有明确的影响 :低AB EPD的片子跨导大 ;高AB EPD的片子跨导小。AB EPD有一临界值 ,当AB EPD高于此值时 ,跨导陡然下降。另外 ,还利用扫描光致发光光谱 (PLmapping)对衬底进行了测量 ,得出了与上述结果相符的结果。 相似文献
3.
如何强化实验室风险管理,保证检测机构检验人员及自身安全,是实验室管理者在风险社会背景下面临的严峻挑战。本文把LEC法和RPN法相结合对硫磺中砷含量的检测过程和检测结果中的风险识别与评价进行应用研究,分析其危害及原因,旨在为实验室风险评估提供方法借鉴,以期提高检测实验室风险评估能力的充分性和有效性。 相似文献
4.
5.
X. J. Bao T. E. Schlesinger W. A. Bonner R. E. Nahory H. L. Gilchrist E. Berry E. A. Beam S. Mahajan 《Journal of Electronic Materials》1991,20(2):207-210
Bulk single crystals of InxGa1-xAs (0.01 <x < 0.12) were successfully grown by the Liquid Encapsulated Czochraski (LEC) technique. These crystals are of high quality
and can provide tunable substrate material for epitaxial application, since the lattice constant may be adjusted by varying
the composition. Nominally undoped crystals were semi-insulating as grown ifx is less than about 0.05. Semi-insulating crystals with higher In composition can be obtained by chromium doping during crystal
growth. The asgrown crystals were studied by 4.2 K photoluminescence spectroscopy (PL) and thermally stimulated current spectroscopy
(TSC). Results from PL measurements indicate good crystal quality and impurity control. TSC spectra reveal several bulk traps
in undoped and Cr doped semi-insulating samples. The activation energies of these traps decrease as In composition is increased.
The amount of change in activation energy is about one third of the bandgap shrinkage due to increased In concentration. 相似文献
6.
砷化镓材料的发展与前景 总被引:2,自引:0,他引:2
综述了世界GaAs材料的生长技术发展状况、生产状况、应用和市场状况及发展趋势。 相似文献
7.
Takashi Fujii Masato Nakajima Tsuguo Fukuda Kouichi Nitta Takeshi Komatsubara 《Journal of Electronic Materials》1987,16(4):219-222
Dislocation-free and low dislocation densityn-type conductive GaAs crystals, 50 mm in diameter, were grown by the In and Si co-doping LEC technique. Two-dimensional LED
arrays were fabricated on substrates obtained from these crystals by the MOCVD technique and the influence of the In doping
on the LED characteristics was examined. The light output power of LEDs fabricated on co-doped substrate with an In concentration
of 1 ×1020atoms/cm3 are low and are non-uniformly distributed, as compared with the boat-grown substrate, even though the co-doped substrate
is dislocation-free. However, the LED properties of a substrate with an In concentration of 2 × 1018atoms/cm3 are the same as those of a boat-grown substrate. The light output power of the LEDs becomes higher as the In concentration
in the substrate decreased. 相似文献
8.
Life-cycle carbon and cost analysis of energy efficiency measures in new commercial buildings 总被引:4,自引:0,他引:4
Joshua Kneifel 《Energy and Buildings》2010,42(3):333-340
Energy efficiency in new building construction has become a key target to lower nation-wide energy use. The goals of this paper are to estimate life-cycle energy savings, carbon emission reduction, and cost-effectiveness of energy efficiency measures in new commercial buildings using an integrated design approach, and estimate the implications from a cost on energy-based carbon emissions. A total of 576 energy simulations are run for 12 prototypical buildings in 16 cities, with 3 building designs for each building-location combination. Simulated energy consumption and building cost databases are used to determine the life-cycle cost-effectiveness and carbon emissions of each design. The results show conventional energy efficiency technologies can be used to decrease energy use in new commercial buildings by 20-30% on average and up to over 40% for some building types and locations. These reductions can often be done at negative life-cycle costs because the improved efficiencies allow the installation of smaller, cheaper HVAC equipment. These improvements not only save money and energy, but reduce a building’s carbon footprint by 16% on average. A cost on carbon emissions from energy use increases the return on energy efficiency investments because energy is more expensive, making some cost-ineffective projects economically feasible. 相似文献
9.
Growth of large-diameter ZnTe single crystals by liquid-encapsulated melt growth methods 总被引:1,自引:0,他引:1
The 80-mm-diameter ZnTe single crystals were successfully obtained by the liquid-encapsulated Kyropoulos (LEK) method. Both
〈100〉- and 〈110〉-oriented single crystals were reproducibly grown by using ZnTe seed crystals. Furthermore, 80-mm-diameter,
〈100〉 and 〈110〉 ZnTe single crystals were obtained by the pulling method. The etch pit densities (EPDs) of the grown crystals
by the LEK and pulling methods were lower than 10,000 cm−2. The strain in the grown crystals by the pulling method was lower than that of LEK crystals. 相似文献
10.
Mingwei Li Wenrui HuNuohu Chen Danling ZengZemei Tang 《International Journal of Heat and Mass Transfer》2002,45(13):2843-2851
A set of numerical analyses for momentum and heat transfer for a 3 in. (0.075 m) diameter Liquid Encapsulant Czochralski (LEC) growth of single-crystal GaAs with or without an axial magnetic field was carried out using the finite-element method. The analyses assume a pseudosteady axisymmetric state with laminar flows. Convective and conductive heat transfers, radiative heat transfer between diffuse surfaces and the Navier-Stokes equations for both melt and encapsulant and electric current stream function equations for melt and crystal are considered together and solved simultaneously. The effect of the thickness of encapsulant, the imposed magnetic field strength as well as the rotation rate of crystal and crucible on the flow and heat transfer were investigated. 相似文献