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Ballistic response of skin simulant against fragment simulating projectiles

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Defence Technology（防务技术） 2023年第12期30卷 70-82页

作者： Punit kumar Pandey Atul Harmukh M.k.khan M.A.Iqbal S.G.Ganpule Department of Mechanical and Industrial Engineering Indian Institute of Technology Roorkee247667India Department of Civil Engineering Indian Institute of Technology Roorkee247667India Department of Design Indian Institute of Technology Roorkee247667India

The response of biological phantoms against high velocity impact is actively sought for applications in defense,space,soft robotics and *** this end,we study the ballistic response of silicone based skin simulant against fragment *** a pneumatic gas gun setup,six chisel-nosed and three regular shaped(sphere,cylinder,and cube)fragments were impacted on the skin *** resulting skin simulant response was studied in terms of ballistic limit velocities,energy densities,failure pattern,and the mechanics of *** results indicate that the shape of the fragment affects the ballistic limit *** ballistic limit velocities,energy densities of the chisel-nosed fragment simulating projectiles were relatively insensitive to the size(mass),except for the smallest(0.16 g)and largest(2.79 g)chisel-nosed *** the same size(1 g),ballistic limit velocities and failure are dependent on the shape of the *** skin simulant failed by combined plugging and elastic hole *** in the spherical fragment was dominated by the elastic hole enlargement,whereas plugging failure was dominant in all other *** spherical,cylindrical,and chisel-nosed fragments created circular cavities,and the cubical fragment created a square *** the case of the spherical fragment,slipping of the fragment within the skin simulant was *** fragments created lateral cracks emanating from the corners of the square ***,for all the fragments,the maximum deformation corresponding to the perforation was lower than the non-perforation indicating rate dependent,stress driven *** maximum deformation was also dependent on the shape of the ***,these results provide unique insights into the mechanical response of a soft simulant against ballistic *** have utility in the calibration and validation of computational models,design of personal protective equipment,and antipersonnel syste

关键词： Skin simulant Fragment Impact Ballistic limit velocity Energy density Failure

TOTAL ENERGIES AND ELECTRONIC STRUCTURES OF CO_3Ti AND HYDROGENIZED Co_3Ti

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Acta Metallurgica Sinica(English Letters) 1998年第3期11卷 197-201页

作者： S.Q.Duan S.J.Liu B.k.Ma Beijing Normal Univ Beijing China

Electronic structure calculations using the tighting-binding linear muffin-tin orbital (TB-LMTO) method have been performed for Co3Ti and its hydride CO3Ti. The computed values of lattice constants and bulk moduli agree with the experiment values. The theoritical excess enerpy and lattice staid due to hydrogen absorption consequently obtained hem the ab initio results indicate that H has the tendency to stay in Co3Ti and the ionicities of Co atomic spheres due to hydmpen absorption change from the canons to the ations. On the other hand, the changes of band structures due to hydrogenation are found to be remarkable.

关键词： total enerpy electronic structure hydrogenized Co3Ti

Crystallization kinetics of Sn_(40)Se_(60) thin films for phase change memory applications

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Journal of Semiconductors 2015年第6期36卷 17-20页

作者： Joshua M.kundu Patrick M.karimi Walter k.Njoroge Department of Physics Kenyatta University

The crystallization kinetics of Sn4oSe6o thin films has been successfully investigated using sheet resis- tance versus temperature measurements. Thermal evaporation was used to deposit the films on ordinary glass sub- strates. The crystallization temperature for Sn4oSe60 thin film was found to be 156.6 -t- 0.3 ~C. In the as-deposited state, the sheet resistance was found to be 195 Mf2/[2, this value declined to 1560 f2/[2] upon annealing. The value of activation energy obtained from the kissinger plot was 0.62 ＋ 0.07 eV. From the results obtained, SnaoSe60 is a promising alloy for PCM application because of its high electrical contrast, high crystallization temperature, and relatively high activation energy.

关键词： crystallization temperature activation energy electrical contrast phase change memory

Prediction of the residual strength of clay using functional networks

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Geoscience Frontiers 2016年第1期7卷 67-74页

作者： S.Z.khan Shakti Suman M.Pavani S.k.Das Civil Engineering Department BIETBPUT Civil Engineering Department National Institute of Technology Rourkela

Landslides are common natural hazards occurring in most parts of the world and have considerable adverse economic effects. Residual shear strength of clay is one of the most important factors in the determination of stability of slopes or landslides. This effect is more pronounced in sensitive clays which show large changes in shear strength from peak to residual states. This study analyses the prediction of the residual strength of clay based on a new prediction model, functional networks（FN） using data available in the literature. The performance of FN was compared with support vector machine（SVM） and artificial neural network（ANN） based on statistical parameters like correlation coefficient（R）, Nash–Sutcliff coefficient of efficiency（E）, absolute average error（AAE）, maximum average error（MAE） and root mean square error（RMSE）. Based on R and E parameters, FN is found to be a better prediction tool than ANN for the given data. However, the R and E values for FN are less than SVM. A prediction equation is presented that can be used by practicing geotechnical engineers. A sensitivity analysis is carried out to ascertain the importance of various inputs in the prediction of the output.

关键词： Landslides Residual strength Index properties Prediction model Functional networks

Do Chinese Retail Option Traders know Anything about Market Volatility？

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Frontiers of Business Research in China 2012年第4期6卷 508-526页

作者： Ming-Hua Liu Nanda k. Rangan Faculty of Business and Law Auckland University of Technology Auckland 1020 New Zealand School of Business Virginia Commonwealth University Richmond VA 23284-4000 USA

This paper examines the information content of implied volatility in the Chinese covered warrant market and finds that the implied volatility is consistently higher than the realized volatility for .all warrants and across all maturities. The implied volatility has very little information content for future volatility in the Chinese warrant market which is dominated by retail investors. Possible explanations for the results are regulatory issues such as restrictions on the short-selling of warrants, differential trading rules for stocks and warrants, high leverage and low trading costs and a market dominated by retail investors.

关键词： covered warrants equity warrants implied volatility option trading

Spatial distribution of display sites of Grey Peacock-pheasant in relation to micro-habitat and predators during the breeding season

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Avian Research 2018年第2期9卷 111-122页

作者： Somying Thunhikorn Matthew J.Grainger Philip J.k.McGowan Tommaso Savini Conservation Ecology Program School of Bioresources and Technology King Mongkut’s University of Technology Thonburi School of Biology Newcastle University

Background： The destruction and fragmentation of forest in Southeast Asia is accelerating biodiversity loss, resulting in a range of management and conservation actions. For some species, a detailed understanding of microhabitat selection is critical for this, especially in the breeding ***： To understand the factors that explain how specific habitats are used by the Grey Peacock-pheasant（Polyplectron bicalcaratum） in the breeding season, we used camera trapping and microhabitat sampling to assess the microhabitat selection of males. We also looked at their interaction with predators in an area of 1200 m × 1200 m at the Hua kha khaeng Wildl fe Sanctuary, Tha land, between January and May ***： We show that display scrapes are situated on flatter open areas with small saplings and some vines, typified by low horizontal understory density. We hypothesise that this allows a trade-off between courtship display and the avoidance of predators. Our study showed that the position of Grey Peacock-pheasant display scrapes regularly overlapped with predators within the same microhabitat. We hypothesise that the species＇ behavioural responses to temporal variation in predation risk allows them to avoid most ***： Particular microhabitats are required for Grey Peacock-pheasant *** avoid predators at these places by being active when predators are not.

关键词： Huai kha khaeng Wildlife Sanctuary Display scrape Species accumulation Predator-prey Polyplectron bicalcaratum

Duodenal heterotopic pancreatic tissue:a case report and literature review

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Gastroenterology Report 2015年第3期3卷 262-265页

作者： Rohit Mehra Aswini k.Pujahari Shyam S.Jaiswal Department of Surgery Armed Forces Medical CollegeWanowrieIndia

Heterotopic pancreas is an aberration in the developmental profile of the *** entity is rarely symptomatic and its malignant transformation is even ***,when present,it poses a diagnostic dilemma to clinicians,as little help comes from gastroenteroscopy and *** exploration remains the only option at times,and it is the histopathological examination that finally clears the *** case report reveals the elusive nature of malignancy in heterotopic pancreas in the duodenum.

关键词： heterotopic pancreas malignant transformation small bowel obstruction

Modulated orientation-sensitive terahertz spectroscopy

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Photonics Research 2016年第3期4卷 1-8页

作者： Rohit Singh Deepu koshy George Chejin Bae k.A.Niessen A.G.Markelz Department of Physics and Astronomy Depauw University Department of Physics Virginia Tech Department of Electrical Engineering University at Buffalo Department of Physics University at Buffalo

Intramolecular vibrations of large macromolecules reside in the terahertz range. In particular, protein vibrations are closely spaced in frequency, resulting in a nearly continuous vibrational density of states. This density of vibrations interferes with the identification of specific absorption lines and their subsequent association with specific functional motions. This challenge is compounded with the absorption being dominated by the solvent and local relaxational motions. A strategy for removing the isotropic relaxational loss and isolating specific vibrations is to use aligned samples and polarization-sensitive measurements. Here, we demonstrate a technique to rapidly attain the anisotropic resonant absorbance using terahertz time domain spectroscopy and a spinning sample. The technique, modulated orientation-sensitive terahertz spectroscopy(MOSTS), has a nonzero signal only for anisotropic samples, as demonstrated by a comparison between a silicon wafer and a wire grid polarizer. For sucrose and oxalic acid molecular crystals, the MOSTS response is in agreement with modeled results for the intermolecular vibrations. Further, we demonstrate that, even in the presence of a large relaxational background, MOSTS isolates underlying vibrational resonances.

关键词： THz Modulated orientation-sensitive terahertz spectroscopy

Metallurgical analysis of a failed maraging steel shear screw used in the band separation system of a satellite launch vehicle

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Defence Technology（防务技术） 2016年第5期12卷 380-387页

作者： S.V.S. Narayana MURTY Sushant k. MANWATkAR E Ramesh NARAYANAN Material Characterization Division Materials and Metallurgy Group Vikram Sarabhai Space Centre Trivandrum 695 022 India

Maraging steels have excellent combination of strength and toughness and are extensively used for a variety of aerospace applications. In one such critical application, this steel was used to fabricate shear screws of a stage separation system in a satellite launch vehicle. During assembly preparations, one of the shear screws which connected the separation band and band end block has failed at the first thread. Microstructural analysis revealed that the crack originated from the root of the thread and propagated in an intergranular mode. The failure is attributed to combined effect of stress and corrosion leading to stress corrosion cracking.

关键词： M250 grade maraging steel Shear screw Separation system Mermen band Stress corrosion cracking