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81.
82.
This work investigates the role of crystallization layers’ periodicity and thickness on functional response in chemical solution‐deposited lead zirconate titanate thin films, with periodic, alternating Zr and Ti gradients normal to the surface of the film. The films were processed with a range of layer periodicities and similar total film thickness, in order to relate the number of layers and compositional oscillations to structural and functional response changes. Trends of increased extrinsic contributions to the dielectric and ferroelectric responses are observed with increasing layer periodicity, but are counterpointed by simultaneous reduction in intrinsic contributions to the same. Transmission electron microscopy reveals in‐plane crystallographic discontinuity at individual crystallization interfaces. Samples with smaller periodicity, and thus thinner layers, potentially suffer from grain size refinement and subsequent reduction in domain size, thereby limiting extrinsic contributions to the response. The strong compositional oscillations in samples with larger periodicity result in deep fluctuations to the tetragonal side of the phase diagram, potentially reducing intrinsic contributions to the response. Conversely, piezoresponse force microscopy results suggest that large chemical oscillations in samples with larger periodicity also result in closer proximity to the morphotropic phase boundary, as evidenced by local acoustic softening at switching, signaling potential field‐induced phase transitions.  相似文献   
83.
This research describes the interesterification of Malaysian mango seed oil (MSO) and palm oil mid‐faction (POMF) to develop a cocoa butter equivalent. Fat blends, formulated by binary blends of palm oil mid‐fraction and mango seed oil at different ratios ({100:0}, {60:40}, {50:50}, {40:60}, {0:100}), were subjected to enzymatic interesterification. The solid fat content revealed that all interesterified blends except 100% POMF {0:100} melted completely at body temperature. The interesterified {50:50} blend exhibited a slip melting point (30.35 °C) and saponification value (186.89) close to cocoa butter (P < 0.05). Thermal behaviour analysis by differential scanning calorimetry showed fusion and crystallisation behaviour similar to cocoa butter. Moreover, both the blend and cocoa butter scavenging abilities were based on the 2,2‐diphenyl‐1‐picrylhydrazyl assay, with the concentration required to reduce radical absorbance by 50% (IC50) of 43.08% and 41.1%, respectively. Therefore, the MSO: POMF blend may have use as a health‐promoting food in human diets.  相似文献   
84.
In this paper evaluation of surface active and application properties in liquid detergent formulations containing binary mixtures of anionic–nonionic, and anionic–cationic surfactants is discussed. Surfactants used include: linear alkylbenzene sulfonate (LAS), alcohol ether sulfate (AES-2EO), alcohol ethoxylate (AE-7EO), lauryl dimethyl amine oxide, and alkyl hydroxyethyl dimethyl ammonium chloride (AHDAC). Surface active parameters relating to the effectiveness and efficiency of surface tension reduction were determined from the surface tension data. Non-ideal solution theory was used to determine the degree of interactions between the two surfactants, and the conditions under which a mixture of two surfactants show synergism in surface active properties. Our data indicated that synergism in mixed surfactants increases with the degree of charge difference between the surfactants. In both mixed micelle and mixed monolayer formation, the degree of interactions between the two surfactants in the mixture increased in the following order: LAS/AE < AES-2EO/amine oxide < AES-2EO/AHDAC. This synergistic behavior as presented in this paper leads to unique application properties and improved performance in terms of foam volume, and soil removal which has applications in formulation of dishwashing liquids, and laundry detergents.  相似文献   
85.
The goal of this paper is to emphasize and present briefly the nanotechnology science and its potential impact on the automotive industry in order to improve the production of recent models with an optimization of the safety performance and a reduction in the environmental impacts. Nanomaterials can be applied in car bodies as light weight constructions without compromising the stiffness and crashwortiness, which means less material and less fuel consumption. This paper outlines the progress of nanotechnology applications into the safety features of more recent vehicle models and fuel efficiency, but also emphasis the importance of sustainable development on the application of these technologies and life cycle analysis of the considered materials, in order to meet the society trends and customers demands to improve ecology, safety and comfort.  相似文献   
86.
Pilot contamination (PC) is one of the most crucial problems in massive multiple‐input multiple‐output (MIMO) systems, due to a limited source of the coherence block. In the current study, two pilot assignment schemes proposed for massive MIMO uplink transmission. We divided each cell into two groups of edge and center users under distance‐based user grouping algorithm (DUG), which the aim is finding the best user grouping boundary. The best boundary is where both signal to interference plus noise Ratio (SINR) of edge and center users is maximum, according to the user's distance to base stations (BS). We investigated the location‐aware pilot assignment (LPA) scheme to enhance the quality of services for both groups. In LPA by assuming three pilot groups for adjacent cells and determining the user's distance to BS, the planned pilots assigned to the users according to their distance to the BS. Then, we optimized pilot schedules in each group by maximizing uplink (UL) rate of each user with auction‐based optimization pilot assignment (AOPA). Simulation results show that both DUG and LPA improve the rate of edge users about 70% and the rate of center users about 30%. Joint DUG and AOPA enhance the rate of the edge and center users about 100% and 80% in each group than conventional schemes and about 50% and 10%, compared with the LPA method. Simulation results show that the proposed method is efficient in reducing PC and improving spectral efficiency.  相似文献   
87.
The behavior of micellization of chlorpromazine hydrochloride (CPH) as an antiemetic drug and its inclusion complex formation with β-cyclodextrin (β-CD) was studied using conductometric technique. The binding or association constant of the complexation equilibrium is evaluated from conductometric measurements by using a nonlinear regression method. The resulting K values for micellization as well as complexation are analyzed. The experiments were carried out at different temperatures. It has been found that CPH form only the 1:1 complex. The association constant values are used for evaluation of thermodynamic parameters of complexation, such as ΔGcomplex°, ΔHcomplex° and ΔScomplex°.  相似文献   
88.
In this study, a novel thin-film nanocomposite (TFN) membrane is developed consisting of a cross-linked nano-modified polyvinyl alcohol (PVA) selective layer on an organic acid-modified polyvinylidene fluoride (PVDF) membrane. The nano-modification of the PVA layer is performed via incorporating different amounts of the amine-functionalized multiwalled carbon nanotubes (MWCNTs-NH2) into the PVA matrix. The effect of citric acid on the chemical structure and morphology of the PVDF support is also investigated. The performance of the resultant membranes in the nanofiltration (NF) of MgSO4 and acid yellow-17 aqueous solutions is also studied. The results indicate that the modification of the support with 0.5 wt% of citric acid increased the water permeance from 1.59 L m−2 h−1 bar−1 (LMH/bar) for PVA/PVDF to 4.49 LMH/bar for the PVA/modified PVDF membrane. Furthermore, the optimum value of MWCNT-NH2 (0.6 wt%) increases the permeance of the resultant TFN membrane to 4.94 LMH/bar while maintaining a high rejection. Interestingly, the incorporation of MWCNT-NH2 into the PVA layer and citric acid into the PVDF solution results in a membrane with the highest permeance of 6 LMH/bar.  相似文献   
89.
A generalized form of a semiquantitative method has been developed based on the multilinear least‐squares regression technique applied on the entire FTIR absorbance spectrum of a gaseous mixture to determine components concentration. Thermal degradation of poly(vinyl alcohol) samples with high, PVA(98), and low degree of hydrolysis, PVA(80), has been investigated by TG‐FTIR simultaneous analysis performed in an inert atmosphere. Analysis of gaseous products was carried out using a routine developed in Matlab and this routine returns the product concentration with a reasonable RMS error. The correlation coefficients of the original mixture spectrum with the mixed output were obtained at some specific peak temperatures using irAnalysis software. The first process is the loss of physically adsorbed water which followed by two main processes of thermal degradation. In spite of the similarity of evolved gaseous products, two samples showed some differences in components concentrations identified in the volatile mixture. Acetaldehyde has been identified as the main volatile product in the first thermal degradation step of PVA(98) and PVA(80). The second major degradation product of PVA(80) is acetic acid due to presence of more residual acetate group while 2‐butenal have been identified for PVA(98). Water was mainly produced in the first stage of thermal degradation of PVA(98) while it was identified in the first and second stages for PVA(80). This might be attributed to existence of a competition between water and residual acetate group for elimination that postpones the complete elimination of OH group to the second degradation stage. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42117.  相似文献   
90.
One of the most successful surgeries during the 21st century is total joint replacement (TJR) with material combination of polymer‐on‐metal (PoM). Despite its success, wear particle generation at the interface of the polymer and metal causes eventually implant loosening. Investigating and understanding the wear particles distribution should help in designing implants with better performances. First step towards characterising wear particle distribution is deriving the lubricant behaviour and velocity distribution inside implant gap. Different hyaluronic acid (HA) solutions were subjected to a sinusoidal movement in straight rectangular channels. The velocity profiles along the channel width were measured with Micro Particle Image Velocimetry. HA solution behaviour was found to be dependent on the concentration. Results showed significant differences between the water (Newtonian) and HA behaviour in unsteady flow. The unsteady behaviour of the lubricant depended strongly on its non‐Newtonian viscoelastic behaviour which was due to the time dependent nature of HA solution. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   
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