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11.
The decision to outsource applications development and support to a foreign vendor involves not only the myriad issues pertinent to outsourcing in general, but a host of additional risks and challenges unique to firms operating in different legal and cultural environments. Careful assessment of these issues helps determine whether offshore outsourcing will realize its potential to reduce costs, improve software quality, and achieve economies of scale in skills acquisition.  相似文献   
12.
In a systematic study on silico‐ferrites of calcium aluminum and magnesium (SFCA phases) this investigation focuses on synthesis of silicon‐free SFCA‐type compounds with low‐MgO contents (~1.00 apfu—atoms per formula unit). Previous studies revealed the existence of iron‐rich SFCA phases similar to the SFCA‐I structure with the chemical composition Ca3MgAl6Fe10O28 (Metall Mater Trans B. 2017;48:2207). The experimental results in the quaternary Fe2O3‐CaO‐Al2O3‐MgO system confirm large stability fields of 2 silicon‐free ferrites FCAM‐I and FCAM‐III, which are members of the homologous series M14+6nO20+8n (n = 1, 2). Starting with compositions corresponding to Ca3MgAlxFe16‐xO28 (with increasing aluminum content from x = 0‐12 apfu), it was possible to synthesize these phases with an x‐value ≥2 apfu, which corresponds to Al2O3 contents ≥7.14 wt%. Synthesis of pure silicon‐free ferrites with n = 1 (FCAM‐I) and 2 (FCAM‐III) and silicon‐bearing ferrites with n = 0 (SFCA) was possible. Samples were characterized by electron probe microanalysis, powder diffraction, and subsequently studied using relaxation calorimetry measurements in combination with differential scanning calorimetry for determination of the heat capacities and standard entropies S°(298). The corresponding values are S°(298) = 650.3 ± 4.6 J/mol·K for SFCA, S°(298) = 864.5 ± 6.1 J/mol·K for FCAM‐I, and S°(298) = 1206.2 ± 8.4 J/mol·K for FCAM‐III. These thermodynamic data are a step toward a rigorous quantitative thermodynamic modeling of the iron ore sintering process.  相似文献   
13.
Fluoro-complexes of titanium, zirconium, tin, and antimony improve the natural flame-resistance of wool when applied by a water-in-oil emulsion exhaustion technique in which common dry-cleaning solvents are used. Evaluations of limiting-oxygen and limiting-nitrous-oxide indices indicate that these complexes act predominantly in the solid phase, The treatments are fast to dry-cleaning but only the fluorotitanate and fluorozirconate treatments are fast to washing. Zinc fluoroborate is an effective flame-retardant for wool, cotton, and their blends, and it can be applied by exhaustion or spraying from solvent emulsions. This treatment is fast to dry-cleaning but is affected by washing.  相似文献   
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delta 5-3-Ketosteroid isomerase from Pseudomonas putida is subject to photoinactivation by light of wavelengths greater than 300 nm, specifically in the presence of the competitive inhibitor, 1,4,6-androstatrien-3-one-17 beta-ol (TEO). In the absence of this steroid or in the presence of the nonchromophoric steroidal competitive inhibitor, deoxycholate, the enzyme activity is essentially unaffected by irradiation. Deoxycholate protects the enzyme from the TEO-dependent reaction to a degree which is predictable from the concentrations of deoxycholate and TEO and their respective competitive inhibition constants, thus demonstrating that the inititial velocity of the photoinactivation is dependent upon the fraction of enzyme active sites occupied by TEO. Cholate, which is not a competitive inhibitor, does not protect enzyme activity. Amino acid analyses of hydrochloric acid hydrolysates of the photoinactivated enzyme show no significant differences from that of the native enzyme. However, the fraction of initial enzyme activity remaining correlates quantitatively with the disappearance of one of the four thiol groups in each polypeptide chain of the enzyme. Enzyme irradiated under the same conditions in the absence of TEO does not lose thiol groups.  相似文献   
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17.
The concentration of the residual CrVI and Or111 in the dye-bath can be decreased to acceptable levels by incorporating a-hydroxymonocarboxylic acids in afterchrome dyeing using the normal dye to dichromate ratios, the most suitable being lactic acid. The mechanism is based on the reduction ofCrVI to Cr111 which appears to take place predominantly on the wool fibre. The optimum pH range for the treatment is 3.4 to 3.6. Compounds which are substantive to the wool fibre, such as sulphates, or form stable complexes with CrIII such as ethylenediaminetetracetic acid, may increase the amount of the residual chromium in the bath. Other dicarboxylic and hydroxycarboxylic acids, which are also effective in reducing the concentration of the CrVI in the bath, form stable complexes with Cr111, adversely affecting the concentration of the residual Cr111 in the bath.  相似文献   
18.
Artur Benisek  Edgar Dachs 《低温学》2008,48(11-12):527-529
Low-temperature heat capacities were measured on milligram-sized samples of various mineralogical materials with a heat-pulse calorimeter. The third law entropy was then calculated by fitting and integrating the cp data. In order to determine the uncertainty of the third law entropy, a Monte Carlo technique was adopted to propagate errors through the integration process.Using single crystals, the relative uncertainty of the third law entropy is smallest and only little mass-dependent and amounts to ~0.2% of the total. Sample powders have a larger uncertainty that increases exponentially with decreasing sample mass. For heat-pulse calorimetric measurements on powders weighing 20 mg, derived standard entropies have a relative uncertainty of 0.9% increasing to 4%, if only 6 mg powder were used.  相似文献   
19.
A new class of molecular magnets based on aniline and aminonaphthalene sulfonic acid was previously reported. In the present work, a nonlocal density functional theory study was performed on simple molecular models, to determine the mechanism that stabilizes the parallel alignment of the spin component. The role played by transition metals on the magnetic properties of this kind of systems was also studied within this approximation. The results obtained show a high sensitivity of the magnetic coupling on the molecular geometry as well as on the nature and oxidation state of the metallic atom.  相似文献   
20.
Dachs E  Benisek A 《低温学》2011,51(8):460-464
An experimental method is described for determining the low-temperature heat capacity (Cp) of mg-sized powder samples using the Quantum Design “Physical Properties Measurement System” (PPMS). The powder is contained in an Al pan as an ∼1 mm thick compressed layer. The sample is not mixed with Apiezon N grease, as compared to other methods. Thus, it is not contaminated and can be used for further study. This is necessary for samples that are only available in tiny amounts. To demonstrate the method various samples, all insulating in nature, were studied including benzoic acid, sapphire and different silicate minerals. The measurements show that the method has an accuracy in Cp to better than 1% at T above 30–50 K and ±3–5% up to ±10% below. The experimental procedure is based on three independent PPMS and three independent differential scanning calorimetry (DSC) measurements. The DSC Cp data are used to slightly adjust the PPMS Cp data by a factor . This is done because heat capacities measured with a DSC device are more accurate around ambient T (?0.6%) than PPMS values and is possible because the deviation of PPMS heat capacities from reference values is nearly constant between about 50 K and 300 K. The resulting standard entropies agree with published reference values within 0.21% for the silicates, by 0.34% for corundum, and by 0.9% for powdered benzoic acid. The method thus allows entropy determinations on powders with an accuracy of better than 1%. The advantage of our method compared to other experimental techniques is that the sample powder is not contaminated with grease and that heat capacity values show less scatter at high temperatures.  相似文献   
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