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排序方式: 共有213条查询结果,搜索用时 15 毫秒
21.
A pharmaceutical formulation containing metformin hydrochloride (MET), hydroxypropyl cellulose (HPC), and microcrystalline cellulose (MCC) was wet granulated with varying amounts of water and the structure of the obtained granules was characterized by Raman chemical mapping. Univariate Raman mapping was found to be satisfactory for producing the images of the two components of interest (HPC and MCC). In addition to the images, the average Raman spectra from the maps as well as the micro-Raman spectra from the hot pixels were analyzed. HPC is found to strongly respond to the addition of water, with its domain dissipating and Raman bands becoming weaker as the water addition increases. MCC is also responsive to water, reacting similarly to HPC but to a much smaller extent and only for the largest amounts of water. Granules made with increasing water content also have improved tabletting properties and flow. 相似文献
22.
The present investigation deals with the effect of Al2O3 particle reinforcement on the lubricated sliding behavior of ZA-27 alloy. The composites with 3, 5, and 10 wt% of Al2O3 particles were produced by the compocasting procedure. Tribological properties of alloy and composites were studied, using
block-on-disk tribometer at different specific loads and sliding speeds. The test results revealed that composite specimens
exhibited significantly lower wear rate, but higher coefficient of friction than the matrix alloy specimens in all the combinations
of applied loads and sliding speeds. The improved antiwear characteristics of the composites were influenced by positive effects
of higher frictional heating on compatibility of the composite phases and suppressing micro-cracking tendency. Due to that,
effects of reinforcing hard particles were manifested through the reduced wear rate of composites, especially in conditions
of higher load, lower sliding speeds and higher Al2O3 particle content. In present wear tests, the significant forming of mechanically mixed layers was not noticed, what is confirmed
by the SEM microphotographs. 相似文献
23.
Zlatko Stuni Veljko Djuri
kovi Slobodan Majstorovi Vlado Buljan 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1982,32(2):393-398
The behaviour of sodium thiosulphate pentahydrate in the course of repeated use as a heat-storing medium can be predicted, cycle by cycle, on the basis of a generalised phase-transition equation adapted for incongruently melting material. An indice is derived for this purpose and named ‘coefficient of true phase-transition reversibility’. Its predictive value is shown for three additional incongruently melting materials well known as heat-storing media: CaCl2.6H2O, Na2SO4.10H2O and the mixture Na2SO4.10H2O + 2/3NH4Cl + 2/3NaCJ. 相似文献
24.
Ribaric S Fratric I 《IEEE transactions on pattern analysis and machine intelligence》2005,27(11):1698-1709
This paper presents a multimodal biometric identification system based on the features of the human hand. We describe a new biometric approach to personal identification using eigenfinger and eigenpalm features, with fusion applied at the matching-score level. The identification process can be divided into the following phases: capturing the image; preprocessing; extracting and normalizing the palm and strip-like finger subimages; extracting the eigenpalm and eigenfinger features based on the K-L transform; matching and fusion; and, finally, a decision based on the (k, l)-NN classifier and thresholding. The system was tested on a database of 237 people (1,820 hand images). The experimental results showed the effectiveness of the system in terms of the recognition rate (100 percent), the equal error rate (EER = 0.58 percent), and the total error rate (TER = 0.72 percent). 相似文献
25.
In present study, the effect of Al2O3 particle reinforcement on the sliding behavior of ZA-27 alloy composites was investigated. The composites with 3, 5, and
10 wt% of Al2O3 particles were produced by the compocasting procedure. Tribological properties of unreinforced alloy and composite were studied,
using block-on-disk tribometer under unlubricated sliding conditions at different specific loads and sliding speeds. The worn
surfaces of samples were examined by the scanning electron microscopy (SEM). The test results revealed that those composite
specimens exhibited significantly lower wear rate than the ZA-27 matrix alloy specimens in all combinations of applied loads
and sliding speeds. The difference in the wear resistance of composite with respect to the matrix alloy, increased with the
increase of the applied load/sliding speed and Al2O3 particle content. The highest degree of improvement of the ZA-27 alloy tribological behavior corresponded with change of
the Al2O3 particles content from 3 to 5 wt%. At low sliding speed, moderate lower wear rate of the composites over that of the matrix
alloy was noticed. This has been attributed to micro cracking tendency of the composites. Significantly reduced wear rate,
experienced by the composite over that of the matrix alloy at the higher sliding speeds and loads, could be explained due
to enhanced compatibility of matrix alloy with dispersoid phase and greater thermal stability of the composite in view of
the presence of the dispersoid. Level of wear rate of tested ZA-27/Al2O3 samples pointed to the process of mild wear, which was primarily controlled by the formation and destruction of mechanical
mixed layers (MMLs). 相似文献
26.
In this paper we derive new semi‐analytical expressions for calculating the electromagnetic torque between inclined circular coils in air. The torque calculation has been obtained from the corresponding mutual inductance between inclined circular coils using the filament method. The coils of rectangular cross‐section whose centers are at the same and the different axes have been considered. From this general case it is possible to calculate the torque between all possible coil combinations either with rectangular or neglected cross‐section. Results obtained by the presented approach are in very good agreement with already published data. This method can be used for industrial electromagnetic devices such as torque sensors, transducers and torque‐measuring devices. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
27.
Slobodan D. Dolić Dragana J. Jovanović Krisjanis Smits Biljana Babić Milena Marinović-Cincović Slavica Porobić Miroslav D. Dramićanin 《Ceramics International》2018,44(15):17953-17961
Monoclinic scheelite-type BiVO4 is currently considered as one of the most promising non-titania photocatalysts, wheras tetragonal zircon-type BiVO4 is still poorly understood. Herein, a new and simple synthetic approach was applied and nanostructured single-phase zircon-type BiVO4 was successfully prepared by a controllable ethylene-glycol colloidal route. In addition, nanostructured monoclinic scheelite-type BiVO4 powders were also fabricated through annealing of the as-prepared samples. A comparative study of the two BiVO4 polymorphs was conducted and it turned out that the novel synthetic approach had a significant impact on porosity and photocatalytic performance of zircon-structured BiVO4. All the prepared materials, as-prepared and annealed, were mesoporous, while measured values of specific surface area of some zircon-structured samples (~34?m2/g) were ~7 times higher than those reported thus far for this phase. Interestingly, for the first time, zircon-type BiVO4, previously considered to be a poor photocatalyst, exhibited a better overall performance in degradation of methyl orange compared to monoclinic scheelite-type BiVO4. Hence, it could be expected that the here-presented synthesis and observations will both arouse interest in scarcely studied tetragonal zircon-type BiVO4 and facilitate as well as speed up further research of its properties. 相似文献
28.
Nina ukanovi Slobodan Obradovi Marija Zdravkovi Sinia uraevi Maja Stojkovi Tomislav Tosti Neboja Jasni Jelena orevi Zoran Todorovi 《International journal of molecular sciences》2021,22(6)
Lipids play an essential role in platelet functions. It is known that polyunsaturated fatty acids play a role in increasing platelet reactivity and that the prothrombotic phenotype plays a crucial role in the occurrence of major adverse cardiovascular events. The ongoing increase in cardiovascular diseases’ incidence emphasizes the importance of research linking lipids and platelet function. In particular, the rebound phenomenon that accompanies discontinuation of clopidogrel in patients receiving dual antiplatelet therapy has been associated with changes in the lipid profile. Our many years of research underline the importance of reduced HDL values for the risk of such a rebound effect and the occurrence of thromboembolic events. Lipids are otherwise a heterogeneous group of molecules, and their signaling molecules are not deposited but formed “on-demand” in the cell. On the other hand, exosomes transmit lipid signals between cells, and the profile of such changes can be monitored by lipidomics. Changes in the lipid profile are organ-specific and may indicate new drug action targets. 相似文献
29.
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