全文获取类型
收费全文 | 34篇 |
免费 | 1篇 |
专业分类
化学工业 | 9篇 |
机械仪表 | 1篇 |
建筑科学 | 2篇 |
轻工业 | 3篇 |
水利工程 | 1篇 |
无线电 | 1篇 |
一般工业技术 | 10篇 |
冶金工业 | 6篇 |
原子能技术 | 1篇 |
自动化技术 | 1篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 2篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 4篇 |
2016年 | 2篇 |
2015年 | 1篇 |
2014年 | 1篇 |
2013年 | 4篇 |
2012年 | 1篇 |
2011年 | 3篇 |
2010年 | 2篇 |
2007年 | 2篇 |
2005年 | 1篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1985年 | 1篇 |
排序方式: 共有35条查询结果,搜索用时 109 毫秒
1.
Mariem Nafti Chiraz Hannachi Jaber Hsaini Béchir Hamrouni Habib Nouaïgui 《分离科学与技术》2020,55(15):2772-2778
ABSTRACT A new approach of cloud point extraction CPE procedure is optimized for hexavalent chromium determination in airborne dusts. Triton X-114 is used as a surfactant and 1-(2-pyridylazo)-2-naphthol as a specific complexing agent for the trivalent chromium’s removal from the aqueous phase to isolate hexavalent chromium compounds. The parameters influencing the extraction protocol (pH, surfactant concentration, and temperature are optimized. The obtained detection and quantification limits are 0.1 and 0.4 μg/L, respectively. The linearity is verified, with a regression coefficient close to 0.999 and the extraction recovery exceeds 99%. The method was successfully applied to analyze airborne samples collected from workplaces. 相似文献
2.
Yassine Slimani Sagar E. Shirsath Essia Hannachi Munirah A. Almessiere Moustafa M. Aouna Nouf E. Aldossary Ghulam Yasin Abdulhadi Baykal Bekir Ozçelik Ismail Ercan 《Journal of the American Ceramic Society》2021,104(11):5648-5658
Two phase-based nanocomposites consisting of dielectric barium titanate (BaTiO3 or BTO) and magnetic spinel ferrite Co0.5Ni0.5Nb0.06Fe1.94O4 (CNNFO) have been synthesized through solid state route. Series of (BaTiO3)1-x + (Co0.5Ni0.5Nb0.06Fe1.94O4)x nanocomposites with x content of 0.00, 0.25, 0.50, 0.75, and 1.00 were considered. The structure has been examined via X-rays diffraction (XRD) and indicated the occurrence of both perovskite BTO and spinel CNNFO phases in various nanocomposites. A phase transition from tetragonal BTO structure to cubic structure occurs with inclusion of CNNFO phase. The average crystallites size of BTO phase decreases, whereas that for the CNNFO phase increases with increasing x in various nanocomposites. The morphological observations revealed that the porosity is highly reduced, and the connectivity between grains is enhanced with increasing x content. The optical properties have been investigated by UV−vis diffuse reflectance spectroscopy. The deduced band gap energy (Eg) value is found to reduce with increasing the content of spinel ferrite phase. The magnetic as well as the dielectric properties were also investigated. The analysis showed that CNNFO ferrite phase greatly affects the magnetic properties and dielectric response of BTO material. The obtained findings can be useful to enhance the performances of magneto-dielectric composite-based systems. 相似文献
3.
Yasser Hannachi Amina Rezgui Taoufik Boubaker 《Korean Journal of Chemical Engineering》2014,31(7):1211-1218
The biosorption characteristics of copper(II) ions using Posidonia oceanica biomass were investigated. Experimental parameters affecting the biosorption process such as pH level, contact time, biosorbent dosage and temperature were studied. The equilibrium data were applied to the Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherm models. The Langmuir model fitted very well the equilibrium data, and the maximum uptake of Cu(II) by Posidonia oceanica was found to be 76.92 mg/g. The mean free energy E (10.78 kJ/mol) from the D-R isotherm indicated a chemical ion-exchange mechanism. Kinetic results showed that the pseudo-second-order kinetic model was well fitted to the experimental data. Thermodynamic parameters depicted the exothermic nature of biosorption and the process was feasible and spontaneous. The results of FTIR (Fourier-transform infrared spectroscopy) revealed that carboxyl, amine, and hydroxyl groups on the biomass surface were involved in the biosorption of Cu(II) ions. 相似文献
4.
Elfalleh W Tlili N Nasri N Yahia Y Hannachi H Chaira N Ying M Ferchichi A 《Journal of food science》2011,76(5):C707-C713
This article aims to determine the phenolic, tocopherol contents, and antioxidant capacities from fruits (juices, peels, and seed oils) of 6 Tunisian pomegranate ecotypes. Total anthocyanins were determined by a differential pH method. Hydrolyzable tannins were determined with potassium iodate. The tocopherol (α-tocopherol, γ-tocopherol, and δ-tocopherol) contents were, respectively, 165.77, 107.38, and 27.29 mg/100 g from dry seed. Four phenolic compounds were identified and quantified in pomegranate peel and pulp using the high-performance liquid chromatography/ultraviolet method: 2 hydroxybenzoic acids (gallic and ellagic acids) and 2 hydroxycinnamic acids (caffeic and p-coumaric acids). Juice, peel, and seed oil antioxidants were confirmed by ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC) methods. The highest values were recorded in peels with 25.63 mmol trolox equivalent/100 g and 22.08 mmol TE/100 g for FRAP and ORAC assay, respectively. Results showed that the antioxidant potency of pomegranate extracts was correlated with their phenolic compound content. In particular, the highest correlation was reported in peels. High correlations were also found between peel hydroxybenzoic acids and FRAP ORAC antioxidant capacities. Identified tocopherols seem to contribute in major part to the antioxidant activity of seed oil. The results implied that bioactive compounds from the peel might be potential resources for the development of antioxidant function dietary food. 相似文献
5.
N. Loudhaief H. Labiadh E. Hannachi M. Zouaoui M. Ben Salem 《Journal of Superconductivity and Novel Magnetism》2018,31(8):2305-2312
Cadmium sulfide (CdS) nanoparticles were synthesized by hydrothermal process and have been characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), and energy-dispersive x-ray spectroscopy (EDXS) system. The effect of added CdS nanoparticles on the superconducting properties and flux pinning capability in (Bi,Pb)2Sr2Ca2Cu3Oy system (denoted as (Bi,Pb)-2223) has been reported. Hydrothermal method is an effective route to synthesize CdS nanoparticles with good crystallinity and having average grain size of about 12 nm. Then, small amounts (0–0.4 wt%) of nanosized CdS particles were added to Bi-2233 samples using a solid-state reaction route. The transport critical current densities and the electrical resistivity ρ(T, H) were performed using the four-probe technique. The results show that samples sintered by small amount of CdS nanoparticles (≤?0.3 wt%) exhibit the higher critical current densities and energy pinning in applied magnetic fields compared to free added sample. Consequently, the addition of CdS could introduce effective pinning centers which account for the improvement in superconducting properties in the Bi-2223 materials. 相似文献
6.
7.
Synthesis, crystal structure, vibrational study, 13C, 111Cd CP-MAS-NMR analysis and electrical properties of the compound [N(C3H7)4]2Cd2Cl6, are reported. The latter crystallizes in the triclinic system (space group , Z = 2) with the following unit cell dimensions: a = 9.530(1) Å, b = 11.744(1) Å, c = 17.433(1) Å, α = 79.31(1)°, β = 84.00(1)° and γ = 80.32(1)°. Besides, its structure was solved using 6445 independent reflections down to R = 0.037. The atomic arrangement can be described by alternating organic and inorganic layers parallel to the plan, made up of tetrapropylammonium groups and Cd2Cl6 dimers, respectively. In crystal structure, the inorganic layer, built up by Cd2Cl6 dimers, is connected to the organic ones through van der Waals interaction in order to build cation-anion-cation cohesion. Impedance spectroscopy study, reported in the sample, reveals that the conduction in the material is due to a hopping process. The temperature and frequency dependence of dielectric constants of the single crystal sample has been investigated to determine some related parameters to the dielectric relaxation. 相似文献
8.
Inès Thabti Walid Elfalleh Hédia Hannachi Ali Ferchichi Maria Da Graça Campos 《Journal of Functional Foods》2012,4(1):367-374
The total polyphenol and flavonoids in leaves of Morus alba var. alba, Morus alba var. rosa and Morus rubra were determined and identification of their components was carried out. The total content of phenolics varied between 345.20 and 631.53 mg gallic acid equivalents (GAE)/100 g dry weight (DW) basis. The total amount of flavonoids ranged between 193.87 and 398.33 mg rutin equivalents (RE)/100 g DW. Thirteen compounds were isolated by chromatography, and their structures determined to be mainly flavonol glycosides and phenolic acids. Three novel components were identified as kaempferol-7-O-glucoside, quercetin-3-O-β-glucoside-7-O-α-rhamnoside and quercetin-3-O-rhamnoside-7-O-glucoside, for the first time from mulberry leaves. Others known compounds were also identified. 相似文献
9.
A framework for damage mechanics of concrete is applied to simulate the nonlinear elastic deformation behavior of concrete using finite element method (FEM). A rather simple isotropic damage model containing essentially no adjustable parameters is shown to produce results in remarkably good agreement with sample experimental data: the damage law requires only the fracture energy to be defined completely. The model is achieved by introducing a damage surface that is similar to the yield function in the conventional theory of plasticity. A special form of damage surfaces is constructed to illustrate the application of the model. A new damage criterion, defined as an equivalent strain norm, is proposed, in order to take into consideration the asymmetric behavior of concrete. For verifying the FEM program including the model, deformations predicted by this model are compared with both the experimental ones for the concrete structural model and the ones calculated without application of the continuum damage mechanics.__________Translated from Problemy Prochnosti, No. 3, pp. 57 – 74, May – June, 2005. 相似文献
10.
Bernard Silvi Marcel Allavena Yacine Hannachi Philippe D'Arco 《Journal of the American Ceramic Society》1992,75(5):1239-1246
Periodic pseudopotential Hartree–Fock calculations have been performed on the cristobalite strucure of silica and germanium dioxide in order to investigate the topology of the ground-state Born–Oppenheimer energy surface. For both oxides the averaged X–O bond lengths, the two unequivalent O–X–O bond angles, and the tilt angle have been optimized. The tilt angle, which measures the rotation of the XO4 tetrahedra around their local C 2 axes, is directly related to the O–X–O bond angle and connects the low-temperature phase twin structures; its zero corresponds to the ideal β-phase. For SiO2 the calculated values of these coordinates agree within 1% with 10 K experimental data whereas for GeO2 the agreement between calculation and experiment is much less satisfactory. It is shown that the tilt angle is the most important structural parameter. The structure of β-cristobalite is rationalized on the basis of the energy dependence upon tilt angle and the absence of β-structure in GeO2 is explained. The one-electron properties, i.e., band structure and density of states, have been calculated and are compared with the results of previous calculations carried out by other methods. As expected in Hartree-Fock calculations, the band gap is overestimated. The analysis of the calculated electron density and of density of states projected onto basis orbitals indicates that these oxides are mostly ionic. It is also shown that the GeO bond is more covalent than the SiO one, which explains the different behavior of these two oxides. 相似文献