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排序方式: 共有583条查询结果,搜索用时 31 毫秒
81.
Hammad Ahmed H. Azooz M. A. Marzouk S. Y. Elbatal H. A. 《Journal of Materials Science: Materials in Electronics》2022,33(9):6389-6402
Journal of Materials Science: Materials in Electronics - Novel zinc borate glass doped with mixed rare-earth ions such as erbium (Er3+) and ytterbium (Yb3+) ions were prepared by conventional melt... 相似文献
82.
Multimedia Tools and Applications - Ideally, sophisticated image forgery methods leave no perceptible evidence of tampering. In response to such stringent context, researchers have proposed digital... 相似文献
83.
Gossypol has been identified as a component of bract (FDB) from frost-killed, field-grown cotton by its chromatographic behavior
on films of silica and cellulose (four eluents and five methods of detection). In addition, a derivative of gossypol was detected,
and it was shown chromatographically that gossypol was removed from extracts of FDB by a divalent metal and by aniline. The
total gossypol content, by spectrophotometric determination of gossypol-aniline complex, of FDB was 0.93%, but for a sample
of bract from a cotton plant that had been grown in a hothouse it was only 0.048%. However the free gossypol contents in both
were similar (0.065% and 0.044%, respectively). Both bract samples were from glanded cotton varieties. It is worthwhile to
investigate the effect of gossypol on lung tissue to see if it can contribute to the acute response of byssinosis. In addition,
it is noted that the waste from ginned cotton which is sometimes used as livestock feed may contain gossypol. 相似文献
84.
Imran Memon Qasim Ali Arain Muhammad Hammad Memon Farman Ali Mangi Rizwan Akhtar 《International Journal of Communication Systems》2017,30(16)
The mobile vehicle is gaining popularity nowadays using map services like Google Maps and other mapping services. However, map services users have to expose sensitive information like geographic locations (GPS coordinates) or address to personal privacy concerns as users share their locations and queries to obtain desired services. Existing mix zones location privacy protection methods are most general purposed and theoretical value while not applicable when applied to provide location privacy for map service users. In this paper, we present new (multiple mix zones location privacy protection) MMLPP method specially designed for map services on mobile vehicles over the road network. This method enables mobile vehicle users to query a route between 2 endpoints on the map, without revealing any confidential location and queries information. The basic idea is to strategically endpoints to nearby ones, such that (1) the semantic meanings encoded in these endpoints (eg, their GPS coordinates) change much, ie, location privacy is protected; (2) the routes returned by map services little change, ie, services usability are maintained. Specifically, a mobile client first privately retrieves point of interest close to the original endpoints, and then selects 2 points of interest as the shifted endpoints satisfying the property of geoindistinguishability. We evaluate our MMLPP approach road network application for GTMobiSim on different scales of map services and conduct experiments with real traces. Results show that MMLPP strikes a good balance between location privacy and service usability. 相似文献
85.
Studenovská H Slouf M Rypácek F 《Journal of materials science. Materials in medicine》2008,19(2):615-621
The technique for fabrication of soft porous hydrogels, in which both the size and the orientation of inner pores can be controlled,
was developed. Three-dimensional hydrophilic gels based on poly[2-hydroxyethyl methacrylate] are designed as scaffolds for
regeneration of soft tissues, e.g., nerve tissue. Anisotropic macropores of the size ranging from 10 to 50 μm were formed
(1) by using a porogen-leaching method with a solid organic porogen, (2) by phase-separation during gelation in solvent-nonsolvent
mixture, or (3) by combination of solid porogen elimination and phase-separation. As a porogen, poly(l-lactide) fibers were applied and consequently washed away under mild conditions to obtain desired spatial orientation of
pores. Highly water-swollen polymer gels were characterized with high pressure (low vacuum) scanning electron microscopy (AquaSEM).
The morphology of voids remaining after removing the solid PLLA porogen (the macropores) was clearly shown. 相似文献
86.
Mohamed M. El Nady Fatma S. Ramadan Mahomoud M. Hammad Doaa A. Mousa Naira M. Lotfy 《Petroleum Science and Technology》2018,36(16):1250-1257
The objectives of this study are the correlation between the oil samples recovered from the Lower Cretaceous reservoirs and Lower and Upper Cretaceous source rocks. The investigated biomarkers of five oils indicated the oils were derived from mixed marine and terrigenous (lacustrine) organic matter and deposited under suboxic to anoxic conditions. These oils were also generated from source rocks of high thermal maturity at the peak oil window. So, based on the molecular indicators of organic source input,depositional environment and maturity parameters of oils and extracts, we can conclude that the oil recovered from Al Baraka oil field were derived from Lower Cretaceous source rocks especially KomOmbo (B) source rocks where it reached the oil window. Furthermore, we can indicate that the other lower Cretaceous formations as Abu Ballas Formation will have the opportunity to generate and expel oil at the deeper part of the basin as shown in the eastern part of the basin. 相似文献
87.
Hana Sebestova Hana Chmelickova Libor Nozka Jiri Moudry 《Journal of Materials Engineering and Performance》2012,21(5):764-769
Laser welding is a high power density technology of materials joining that has many advantages in comparison with conventional
fusion welding methods, for example, high accuracy, flexibility, repeatability and especially very narrow heat-affected zone
which results in minimal workpiece distortions. Since it is still quite expensive technology, minimal spoilage is required.
Effective system of quality control and processing parameters optimization must be established to reduce total costs, which
is particularly required in industrial production. In this article some results of pulsed Nd:YAG laser welding process monitoring
based on the measurement of plasma electron temperature are presented. The ability of designed sensor to detect weld penetration
depth has been demonstrated. Plasma spectral lines intensities measurement can discover gap instabilities as well as local
sheet thickness reduction. 相似文献
88.
One of the most important issues in a liquid propellant rocket is to measure the amount of remaining liquid propellant under low gravity environment during space mission. This paper presents the results of experiment and analysis of a pressure–volume–temperature (PVT) method which is a gauging method for low gravity environment. The experiment is conducted using 7.4 l tank for liquid nitrogen with various liquid-fill levels. To maximize the accuracy of a PVT method with minimum hardware, the technique of a helium injection with low mass flow rate is applied to maintain stable temperature profile in the ullage volume. The PVT analysis considering both pressurant and cryogen as a binary mixture is suggested. At high liquid-fill levels of 72–80%, the accuracy from the conventional PVT analysis is within 4.6%. At low fill levels of 27–30%, the gauging error is within 3.4% by mixture analysis of a PVT method with specific low mass flow rate of a helium injection. It is concluded that the proper mass flow rate of a helium injection and PVT analyses are crucial to enhance the accuracy of the PVT method with regard to various liquid-fill levels. 相似文献
89.
Ayman A. Abu Hammad Souma M. Alhaj Ali Ghaleb J. Sweis Rateb J. Sweis 《Canadian Metallurgical Quarterly》2010,26(2):105-112
A probabilistic model is proposed to predict the risk effects on time and cost of public building projects. The research goal is to utilize a real history data in estimating project cost and duration. The model results can be used to adjust floats and budgets of the planning schedule before project commencement. Statistical regression models and sample tests are developed using real data of 113 public projects. The model outputs can be used by project managers in the planning phase to validate the schedule critical path time and project budget. The comparison of means analysis for project cost and time performance indicated that the sample projects tend to finish over budget and almost on schedule. Regression models were developed to model project cost and time. The regression analysis showed that the project budgeted cost and planned project duration provide a good basis for estimating the cost and duration. The regression model results were validated by estimating the prediction error in percent and through conducting out-of-sample tests. In conclusion, the models were validated at a probability of 95%, at which the proposed models predict the project cost and duration at an error margin of ±0.035% of the actual cost and time. 相似文献
90.
Microribonucleic acids (miRNAs) have been linked with various regulatory functions and disorders, such as cancers and heart diseases. They, therefore, present an important target for detection technologies for future medical diagnostics. We report here a novel method for rapid and sensitive miRNA detection and quantitation using surface plasmon resonance (SPR) sensor technology and a DNA*RNA antibody-based assay. The approach takes advantage of a novel high-performance portable SPR sensor instrument for spectroscopy of surface plasmons based on a special diffraction grating called a surface plasmon coupler and disperser (SPRCD). The surface of the grating is functionalized with thiolated DNA oligonucleotides which specifically capture miRNA from a liquid sample without amplification. Subsequently, an antibody that recognizes DNA*RNA hybrids is introduced to bind to the DNA*RNA complex and enhance sensor response to the captured miRNA. This approach allows detection of miRNA in less than 30 min at concentrations down to 2 pM with an absolute amount at high attomoles. The methodology is evaluated for analysis of miRNA from mouse liver tissues and is found to yield results which agree well with those provided by the quantitative polymerase chain reaction (qPCR). 相似文献