全文获取类型
收费全文 | 174篇 |
免费 | 0篇 |
专业分类
化学 | 127篇 |
晶体学 | 3篇 |
力学 | 4篇 |
数学 | 11篇 |
物理学 | 29篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 4篇 |
2020年 | 3篇 |
2018年 | 1篇 |
2017年 | 3篇 |
2016年 | 3篇 |
2015年 | 6篇 |
2014年 | 7篇 |
2013年 | 18篇 |
2012年 | 8篇 |
2011年 | 6篇 |
2010年 | 7篇 |
2009年 | 7篇 |
2008年 | 4篇 |
2007年 | 11篇 |
2006年 | 9篇 |
2005年 | 3篇 |
2004年 | 6篇 |
2003年 | 3篇 |
2002年 | 2篇 |
2001年 | 2篇 |
2000年 | 3篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 5篇 |
1995年 | 3篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1989年 | 1篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1981年 | 5篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1968年 | 2篇 |
1967年 | 1篇 |
1962年 | 2篇 |
1957年 | 3篇 |
1918年 | 1篇 |
排序方式: 共有174条查询结果,搜索用时 15 毫秒
21.
Publications on Adsorption Science and Technology 总被引:2,自引:0,他引:2
S. Sircar 《Adsorption》2000,6(4):359-365
A key word search of Chemical Abstracts Registry and Derwent Patent Index on various topics of Adsorption Science and Technology between 1970–2000 reveals an immense volume of patents and publications in this area. A detailed breakdown of this search is provided. 相似文献
22.
23.
Sircar S Wu H Li J Lueking AD 《Langmuir : the ACS journal of surfaces and colloids》2011,27(23):14169-14179
The intriguing hysteretic adsorption-desorption behavior of certain microporous metal-organic frameworks (MMOFs) has received considerable attention and is often associated with a gate-opening (GO) effect. Here, the hysteretic adsorption of N(2) and Ar to Zn(2)(bpdc)(2)(bpee) (bpdc = 4,4'-biphenyldicarboxylate; bpee = 1,2-bipyridylethene) shows a pronounced effect of allowed experimental time at 77 and 87 K. When the time allowed is on the order of minutes for N(2) at 77 K, no adsorption is observed, whereas times in excess of 60 h is required to achieve appreciable adsorption up to a limiting total coverage. Given sufficient time, the total uptake for N(2) and Ar converged at similar reduced temperatures, but the adsorption of Ar was significantly more rapid than that of N(2), an observation that can be described by activated configurational diffusion. N(2) and Ar both exhibited discontinuous stepped adsorption isotherms with significant hysteresis, features that were dependent upon the allowed time. The uptake of H(2) at 77 K was greater than for both N(2) and Ar but showed no discontinuity in the isotherm, and hysteretic effects were much less pronounced. N(2) and Ar adsorption data can be described by an activated diffusion process, with characteristic times leading to activation energies of 6.7 and 12 kJ/mol. Fits of H(2) adsorption data led to activation energies in the range 2-7 kJ/mol at low coverage and nonactivated diffusion at higher coverage. An alternate concentration-dependent diffusion model is presented to describe the stepwise adsorption behavior, which is observed for N(2) and Ar but not for H(2). Equilibrium is approached very slowly for adsorption to molecularly sized pores at low temperature, and structural change (gate opening), although it may occur, is not required to explain the observations. 相似文献
24.
S. Sircar 《Adsorption》1996,2(4):323-326
The capital and energy costs of production of oxygen enriched air by a rapid pressure swing adsorption (RPSA) process can be reduced by decoupling the air drying and the air separation duties of the process. Integration of the oxygen-RPSA process with an enhanced combustion application system allows thermal swing adsorption drying of air feed to the RPSA process. The air separation process then can be run using an ad(de)sorption pressure envelope of 2:1 atmospheres, which significantly reduces the cost and energy of operation of the air compressor. 相似文献
25.
The performance of a novel nanoporous carbon membrane for separation of hydrogen-hydrocarbon gas mixtures is described. The membrane selectively adsorbs hydrocarbons from hydrogen at the high pressure side and the adsorbed molecules then diffuse along the pore walls to the low pressure side. Pressure levels at thigh gh and low pressure sides of the membrane and the type and flow rate of the sweep gas at the low pressure side of the membrane were varied. The effects of these variables on the hydrogen recovery and hydrocarbon rejection by the membrane were investigated. 相似文献
26.
One vision of clean energy for the future is to produce hydrogen from coal in an ultra-clean plant. The conventional route
consists of reacting the coal gasification product (after removal of trace impurities) with steam in a water gas shift (WGS)
reactor to convert CO to CO2 and H2, followed by purification of the effluent gas in a pressure swing adsorption (PSA) unit to produce a high purity hydrogen
product. PSA processes can also be designed to produce a CO2 by-product at ambient pressure. This work proposes a novel concept called “Thermal Swing Sorption Enhanced Reaction (TSSER)”
which simultaneously carries out the WGS reaction and the removal of CO2 from the reaction zone by using a CO2 chemisorbent in a single unit operation. The concept directly produces a fuel-cell grade H2 and compressed CO2 as a by-product gas. Removal of CO2 from the reaction zone circumvents the equilibrium limitations of the reversible WGS reaction and enhances its forward rate
of reaction. Recently measured sorption-desorption characteristics of two novel, reversible CO2 chemisorbents (K2CO3 promoted hydrotalcite and Na2O promoted alumina) are reviewed and the simulated performance of the proposed TSSER concept using the promoted hydrotalcite
as the chemisorbent is reported. 相似文献
27.
The usefulness of the pseudo SU(3) weak coupling limit for the study of even-even nuclei for which the protons and neutrons fill different major oscillator shells is examined. The content of proton and neutron configurations in the total wave function of the coupled space is estimated in order to understand their relative importance. The structure of 144Ba is investigated in detail. Our calculations show that both proton and neutron configurations are important to study the collective excitations in nuclei and perhaps the strong coupling limit is more appropriate for nuclei such as those considered in this work. 相似文献
28.
B. R. Ratna 《Molecular Crystals and Liquid Crystals》2013,570(3-4):205-210
Abstract Magnetic (ΔnH ) and electric birefringence (ΔnE ) in the isotropic phase of strongly positive (Δ 8)trans-p-n-octyloxy α-methyl-p'-cyanophenyl cinnamate (8 OMCPC) have been measured. It is established that they both exhibit a (T - T*)?1 dependence, T NI - T* being 1.4 K. Also, the induced birefringence is found to be proportional to the square of the applied field, magnetic or electric. 相似文献
29.
AbstractThis paper studies the problem of understanding implied volatilities from options written on leveraged exchanged-traded funds (LETFs), with an emphasis on the relations between LETF options with different leverage ratios. We first examine from empirical data the implied volatility skews for LETF options based on the S&P 500. In order to enhance their comparison with non-leveraged ETFs, we introduce the concept of moneyness scaling and provide a new formula that links option implied volatilities between leveraged and unleveraged ETFs. Under a multiscale stochastic volatility framework, we apply asymptotic techniques to derive an approximation for both the LETF option price and implied volatility. The approximation formula reflects the role of the leverage ratio, and thus allows us to link implied volatilities of options on an ETF and its leveraged counterparts. We apply our result to quantify matches and mismatches in the level and slope of the implied volatility skews for various LETF options using data from the underlying ETF option prices. This reveals some apparent biases in the leverage implied by the market prices of different products, long and short with leverage ratios two times and three times. 相似文献
30.
Adsorption of Cr(III) from both synthetic and real samples of tannery wastewater treatment's effluent on chitin-humic acid (chitin-HA) hybrid has been carried out. Rate constant and capacity of adsorption of Cr(III) from the synthetic sample were investigated and removal of Cr(III) from the real sample was tested at optimum medium acidity equivalent to pH 3.5. Characterization using Fourier transform infra red (FT-IR) spectroscopy revealed that both COO− and N-acetyl originated from respectively humic acid (HA) and chitin were involved on the adsorption of Cr(III), and hence the Freundlich's multilayer and multi-energy adsorption model was more applicable to treat the adsorption data than the Langmuir's monolayer and mono-energy model. The quantification of adsorption capacity and rate constant using Freundlich isotherm model and first order adsorption reaching equilibrium yielded values of 6.84 × 10−4 mol g−1 (35.57 mg g−1) and 1.70 × 10−2 min−1, respectively. Removal test for the real wastewater treatment's effluent showed that the maximum amount of Cr(III) could be removed by 1 g of chitin-HA hybrid was 2.08 × 10−4 mol or equivalent to 10.82 mg. 相似文献