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Numerical Calculation of Concrete Slab Response to Blast Loading

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Transactions of Tianjin University 2006年第B9期12卷 94-99页

作者： ZHOU Xiaoqing HAO Hong KUZNETSOV Valerian A WASCHL John School of Civil and Resource Engineering The University of Western Australia Australia Weapons System Division Defence Science and Technology Organisation Department of Defence Australia

In the present paper, a dynamic plastic damage model for concrete has been employed to estimate responses of a reinforced concrete slab subjected to blast loading. The interaction between the blast wave and the concrete slab is considered in 3D simulation. In the first stage, the initial detonation and blast wave propagation is modelled in 2D simulation before the blast wave reaches the concrete slab, then the results obtained from 2D calculation are remapped to a 3D model. The calculated blast load is compared with that obtained from TM5-1300. Numerical results of the concrete slab response are compared with the explosive test carried out- in the Weapons System Division, defence Science and Technology Organisation, Department of defence, Australia.

关键词： blast loading damage concrete 3 D simulation

Feasibility analysis of WDM links for radar applications

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defence Technology（防务技术） 2015年第1期11卷 76-84页

作者： D.MEENA FREDY FRANCIS K.T.SARATH E.DIPIN T.SRINIVAS Applied Photonics Lab ECE Department Indian Institute of Science(IISc) Electronics and Radar Development Establishment (LRDE) DRDO(Ministry of Defence) Bangalore India Model Engineering College Thrikkakara Cochin India

Active phased array antennas enhances the performance of modern radars by using multiple low power transmit/receive modules in place of a high power transmitter in conventional radars. Fully distributed phased array radars demand the distribution of various signals in radio frequency(RF) and digital domain for real time operation. This is normally achieved through complex and bulky coaxial distribution networks. In this work, we intend to tap the inherent advantages of fiber links with wavelength division multiplexed(WDM) technology and a feasibility study to adapt these links for radar applications is carried out. This is done by analysing various parameters like amplitude, delay, frequency and phase variation response of various radar waveforms over WDM links. This also includes performance evaluation of non-linear frequency modulation(NLFM) signals, known for better signal to noise ratio(SNR) to specific side lobe levels. NLFM waveforms are further analysed using pulse compression(PC) technique. Link evaluation is also carried out using a standard simulation environment and is then experimentally verified with other waveforms like RF continuous wave(CW), pulsed RF and digital signals. Synchronization signals are generated from this variable duty cycle digital signals during real time radar operation. During evaluation of digital signals, variable transient effects for different duty cycles are observed from an amplifier configuration. A suppression method is proposed to eliminate this transient effects. Further, the link delay response is investigated using different lengths of fiber spools. It can be inferred from the experimental results that WDM links are capable of handling various signals significant to radar applications.

关键词： WDM Radar RF over fiber EDFA transient Delay CW Pulsed CW NLFM

Implications of fine water mist environment on the post-detonation processes of a PE4 explosive charge in a semi-confined blast chamber

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defence Technology（防务技术） 2018年第5期14卷 366-372页

作者： Zetu Jiba Tleyane Jonas Sono Frederik Johannes Mostert Council for Scientific and Industrial Research (CSIR) Defence Peace Safety and Security

The effects of a fine water mist environment in a semi-confined blast chamber on the chemical and thermodynamic processes following detonation of a 20 g PE4 explosive charge have been *** effects were quantified by the analysis of pressure profiles recorded where several parameters including arrival time of the shock at the sensors, peak overpressures, specific impulse of the positive phase, period of the negative phase and the specific impulse of the multiple reflections were *** effect of the fine water mist on the arrival time, peak pressures and the specific impulse of the positive phase agrees with previous findings in literature. In this paper, the focus is on the implications of the fine water mist on the negative phase and the impulse of multiple pressure reflections. The period of the negative phase was found to have increased by 40% and with higher negative peak pressure in the mist condition compared to the atmospheric condition. The activities of the multiple pressure reflections were found to have decreased considerably, both in number and in amplitude leading to lower impulses(by about 60%) for the water mist conditions.

关键词： Fine water mist Blast mitigation Semi-confined blast chamber Negative phase pressure Multiple pressure reflections

Spin-Relaxation of NiO Encapsulated Gd_2O_3 Core–Shell Nanoparticles

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Acta Metallurgica Sinica(English Letters) 2014年第2期27卷 253-258页

作者： A.Rajesh M.Manivel Raja K.Gurunathan Department of Nanoscience and Technology Science BlockAlagappa University defence Metallurgical Research Laboratory

Nickel oxide encapsulated gadolinium oxide （Gd203~IiO） core-shell nanoparticles （Nps） has been synthesized by polyol method and analyzed by transmission electron microscopy. The particle size is found to vary from 25 to 35 nm. Raman spectra show the gadolinium oxide core material peaks are found to be diminished by the mass effect of the NiO shell material. The dynamics of the magnetic moment has been studied with the help of temperature dependent electron paramagnetic resonance （EPR） spectroscopy. Peak-to-peak line width （AHpp） value of the EPR spectra increases with decreasing temperature. Temperature dependence of line width shows the dominance of spin-lattice relaxation in these systems, and it can be used as T~ contrast agent. Spin number estimated from EPR studies increases with the decrease of the temperature. The interfacial exchange coupling between the core and shell region is found to be existing at very low temperatures as determined by EPR studies in this non-magnetic/antiferromagnetic （NM/AFM） core/shell nanosystem. The effects of the temperature on the magnetic properties of the Gd203/NiO core/shell NPs and the underlying mechanism have been discussed.

关键词： Nanocomposite Magnetic material Raman spectroscopy Electron paramagnetic resonance(EPR) Spin-relaxation

Multi-policy threshold signature with distinguished signing authorities

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The Journal of China Universities of Posts and Telecommunications 2011年第1期18卷 113-120页

作者： WANG Feng ZHOU You-sheng GU Li-ze ZHENG Shi-hui YANG Yi-xian Information Security Center State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing 100876 China Key Laboratory of Network and Information Attack and defence Technology Ministry of Education Beijing University of Posts and Telecommunications Beijing 100876 China

Threshold signature plays an important role to distribute the power of a single authority in modem electronic society. In order to add functions and improve efficiency of threshold signatures, a multi-policy threshold signature scheme with distinguished signing authorities is proposed. In the scheme two groups can sign and verify each other, so the scheme is two-way signing and verifying. Moreover, the threshold values of the two groups can change with the security classification of the signing document, every discretionary signatory only signs a small part of the document instead of the whole one, so the bandwidth of data transmission for group signature construction can be reduced and the size of group signature is equivalent to that of any individual signature.

关键词： threshold signature multi-policy group verified distinguished signing authorities

Dengue virus non-structural 1 protein interacts with heterogeneous nuclear ribonucleoprotein H in human monocytic cells

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Asian Pacific Journal of Tropical Medicine 2016年第2期9卷 109-114页

作者： Drishya Diwaker Mishra K P Ganju L Singh S B Immunomodulation Lab Defence Institute of Physiology & Allied Sciences

Objective: To study protein-protein interaction between heterogeneous nuclear ribonucleoprotein H(hn RNP H) and Dengue virus(DENV) proteins. Methods: DENV proteins were screened against the host hn RNP H protein, in order to identify the host-viral protein-protein interactions in DENV infected THP-1 cells by co-immunoprecipitation. The co-localization of the interacting proteins was further confirmed by immunofluorescence microscopy. Results: The host protein hn RNP H was found to interact with DENV nonstructural 1 protein and help the virus to multiply in the cell. Conclusions: The non-structural 1 glycoprotein is a key modulator of host immune response and is also involved in viral replication. Therefore, disruption of this key interaction between hn RNP H and DENV nonstructural 1 could be an important therapeutic strategy for management of DENV infection.

关键词： Dengue virus Non-structural 1 protein Heterogeneous nuclear ribonucleoprotein H Protein interactions

Uniform fabrication of Ge nanocrystals embedded into SiO2 film via neutron transmutation doping

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Progress in Natural Science:Materials International 2014年第5期24卷 226-231页

作者： Wei Liu Tiecheng Lu Qingyun Chen Youwen Hu Shaobo Dun Issai Shlimak Department of Physics and Key Laboratory for Radiation Physics and Technology of ministry of Education Sichuan University School of National defence and Technology Southwest University of Science and Technology Minerva Center and Jack and Pearl Resnick Institute of Advanced Technology Department of Physics Bar-Ilan University

Nanocrystalline74Ge embedded SiO2 films were prepared by employing ion implantation and neutron transmutation doping *** electron microscopy, energy dispersive x-ray spectroscopy, and photoluminescence of the obtained samples were measured. The existence of As dopants transmuted from74 Ge is significant to guarantee the uniformity and higher volume density of Ge nanocrystals by tuning the system’s crystallinity and activating mass transfer process. It was observed that the photoluminescence intensity of Ge nanocrystals increased first then decreased with the increase of arsenic concentration. The optimized fluence of neutron transmutation doping was found to be5.5 1017 cm 2to achieve maximum photoluminescence emission in Ge embedded SiO2 film. This work opens a route in the three-dimensional nanofabrication of uniform Ge nanocrystals.

关键词： Ge nanocrystals Ion implantation Neutron transmutation doping Photoluminescence property

Altered Host Resistance to Listeria monocytogenes In Mice Exposed to 1-Chloroacetophenone (CN) Vapours

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Biomedical and Environmental Sciences 1992年第2期5卷 142-148页

作者： PRADEEP KUMAR PRAVIN KUMAR K.ZACHARIAH G.P.RAI R.VIJAYRAGHAVAN defence Research and Development Establishment Tansen RoadDefence Research and Development Establishment Tansen RoadDefence Research and Development Establishment Tansen RoadDefence Research and Development Establishment Tansen RoadDefence Research and Development Establishment Tansen Road Gwalior 474002 India Gwalior 474002 India Gwalior 474002 IndiaGwalior 474002 IndiaGwalior 474002 India

Short term repeated exposure of 1-chloroacetophenone (CN) vapours at a concentration of 0.153 mg per litre for 15 minutes daily on 10 consecuitve days in Swiss albino male mice resulted in increased mortality to Listeria monocytogenes. Significantly elevated bacterial growth was observed in the spleen and liver of the CN exposed animals. The increased bacterial count in these organs was evident within 4-6 days post challenge as compared to vehicle exposed infected and unexposed infected animals. Increased susceptibility to infection has been considered to be the function of immune alteration due to cumulative short term effects ofCN vapour inhalation. This may be attributed to immunotoxic effects of CN on Tcells mediated macrophage functions.

关键词： CN Vapours Altered Host Resistance to Listeria monocytogenes In Mice Exposed to 1-Chloroacetophenone

Simulation and Experimental Research of a Novel Vircator

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Chinese Physics Letters 2008年第7期25卷 2566-2568页

作者：李志强钟辉煌樊玉伟舒挺杨建华袁成卫许流荣赵延宋 College of Optoelectric Science and Technology National University of Defence Technology Changsha 410073

A new configuration of an axially-extracted vircator with three resonant cavities is put forward and optimized by simulation with the PIC code. The output power of over 1 GW is obtained at around 4.1 GHz in the experiment, in agreement well with the PIC simulation results. The beam to wave power conversion efficiency is more than 6.6%.

关键词： VIRTUAL CATHODE OSCILLATOR BAND