Study on liquid-filled structure target with shaped charge vertical penetration

Based on the characteristic expanded hole of a shaped charge jet(SCJ) for target penetration and the reflow characteristics of liquids,the liquid-filled structure of a target disturbs the stability of the SCJ acquired in two independent parts.The interference jet speed interval,the escape jet speed interval,and the surplus depth are calculated on the basis of the virtual origin theory.The experimental results,including the velocity of the escaped jet tip and the surplus depth of penetration,are consistent with the theoretical results.Experiments show that the theory can describe the interaction process of the target with a shaped charge jet.

Design and comparison of minimal symmetric model-subset for maneuvering target tracking

Model-set is utilized in state estimation for maneuver- ing target tracking. Two minimal symmetric model-subsets are designed and investigated by moment matching method, which include hypersphere-symmetric model-subset and axis-symmetric model-subset, if system mode is a random variable and obeys certain probability distribution. They can be used as the fun- damental model-subset for multiple models estimation with fixed structure, variable structure and moving bank. The model-groups constructed by above designed subsets are given, which give the practical guidance for use of model-set in multiple models ap- proach with a variable structure. Simulation results show that the performances of two minimal model-set significantly outperform the corresponding model-sets with fixed spacing.

Investigation of system structure and information processing mechanism for cognitive skywave over-the-horizon radar

Based on the cognitive radar concept and the basic connotation of cognitive skywave over-the-horizon radar（SWOTHR）, the system structure and information processingmechanism about cognitive SWOTHR are researched. Amongthem, the hybrid network system architecture which is thedistributed configuration combining with the centralized cognition and its soft/hardware framework with the sense-detectionintegration are proposed, and the information processing framebased on the lens principle and its information processing flowwith receive-transmit joint adaption are designed, which buildand parse the work law for cognition and its self feedback adjustment with the lens focus model and five stages informationprocessing sequence. After that, the system simulation andthe performance analysis and comparison are provided, whichinitially proves the rationality and advantages of the proposedideas. Finally, four important development ideas of futureSWOTHR toward ＂high frequency intelligence information processing system＂ are discussed, which are scene information fusion, dynamic reconfigurable system, hierarchical and modulardesign, and sustainable development. Then the conclusion thatthe cognitive SWOTHR can cause the performance improvement is gotten.

Research on One-Piece Structure Target Flow Sensing Technology Based on Fiber Bragg Grating

In view of problems existing in the detection of the traditional hydraulic system, such as the large volume of sensor and the low measurement accuracy, a new one-piece target type flow sensor is designed and researched based on fiber Bragg grating （FBG）. A compact structure is designed, which is convenient to be dismantled, processed, and installed, based on the analysis of the principle of FBG and the structure of target type flow sensor. The force of target put in fluid flow is turned into the FBG wavelength drift, with a corresponding relationship. The problem on the cross sensitivities of the temperature and strain is solved effectively by using double FBG symmetrically pasted on the both surfaces of the cantilever. The impact on the fluid state is analyzed through simulation in the software FLUENT, and the results show that the impact was smaller than that of the traditional structure. The results of experiments in the hydraulic system show that there is a good linear relationship between the change in the dual FBG central wavelength and mass loading on the target sheet has a good linear relationship, and the sensitivity is twice that of a single FBG sensitivity.

Synthesis of hollow and mesoporous structured NaYF4：Yb,Er upconversion luminescent nanoparticles for targeted drug delivery

In this paper, we demonstrated a one-step template-free strategy to fabricate a hollow mesoporous structured NaY F4：Yb,Er nanoparticles with excellent upconversion luminescence. Folic acid（FA）, a commonly used cancer-targeting agent, was conjugated on the surface of the nanoparticles based on the presence of free amine groups, which were labeled as NaY F4：Yb,Er-FA HMUCNPs. The properties were extensively studied, which indicated the obtained samples showed a typical hollow mesoporous structure and excellent upconversion luminescence that were useful for cell imaging and drug delivery. The L929 cells viability, hemolysis assay and coagulation test demonstrated good biocompatibility of the samples. The anti-cancer drug doxorubicin hydrochloride（DOX） storage/release properties were demonstrated to be pH-responsive, in which, the drug release might be beneficial at the reduced pH for targeted release and controlled therapy. Moreover, it was found that DOX-loaded NaY F4：Yb,Er-FA HMUCNPs exhibited greater cytotoxicity to KB cells than free DOX due to the specific cell uptake by KB cells via folate receptor-mediate endocytosis. Therefore, the multifunctional nanoparticles combining upconversion luminescent property and hollow mesoporous structure have potential for simultaneous targeted anti-cancer drug delivery and cell imaging.

The Skills of Practical Writing for TourGuide(Ⅱ) ——Points for Attention

This thesis is about the skills of practical writing for Tour Guide.This article dissertates several points--the interpretation of the source language,structure of the target language and choice of the right word,that should be given more attention in translation.As a Tour Guide,one needs to have these skills and the ability of describing sceneries beautifully and accurately by writing.

3D geological suitability evaluation for underground space based on the AHP-cloud model

Urban development continues to reduce the amount of available ground space.The development of underground space is thus gath-ering increasing attention to alleviate ground congestion.However,there is currently a lack of a three-dimensional(3D)evaluation method to systematically evaluate the geological conditions of underground space and possible geological disaster risks caused by rock and soil masses.This paper presents an engineering geological suitability assessment framework based on 3D geological modeling and an analytic hierarchy process(AHP)-cloud model.As the basis for 3D evaluation,a 3D structural model of the study area is established based on the drilling data and geological profiles.Then the structural model is partitioned to obtain interpolation grids,and the ordinary Kriging interpolation method is applied to attribute interpolation.All the attributes are exported from the geological model,and the rock and soil masses are divided into four categories according to their engineering properties,namely soft soil,sandy soil,cohesive soil,and rock,upon which a targeted hierarchy structure is established based on the attributes that impact the suitability.This paper intro-duces the cloud model to characterize the uncertainty of these evaluation indexes,which synthesizes an AHP method,thus it is referred to as the AHP-cloud model.This new model is used to evaluate the geological suitability of underground space in the Sanlong Bay district,Foshan City,Guangdong,China.In addition,we also determine the excavation difficulty at different depths according to the lithology and weathering degree of the study area.The limitations and future directions of the proposed method are discussed,including the influ-encing factors and weight determination.

Relativistic electron acceleration by surface plasma waves excited with high intensity laser pulses

The process of high energy electron acceleration along the surface of grating targets(GTs)that were irradiated by a relativistic,high-contrast laser pulse at an intensity I=2.5×10^20 W/cm^2 was studied.Our experimental results demonstrate that for a GT with a periodicity twice the laser wavelength,the surface electron flux is more intense for a laser incidence angle that is larger compared to the resonance angle predicted by the linear model.An electron beam with a peak charge of∼2.7 nC/sr,for electrons with energies>1.5 MeV,was measured.Numerical simulations carried out with parameters similar to the experimental conditions also show an enhanced electron flux at higher incidence angles depending on the preplasma scale length.A theoretical model that includes ponderomotive effects with more realistic initial preplasma conditions suggests that the laser-driven intensity and preformed plasma scale length are important for the acceleration process.The predictions closely match the experimental and computational results.

Fabrication of micrometre-sized periodic gratings in free-standing metallic foils for laser-plasma experiments

Engineered targets are expected to play a key role in future high-power laser experiments calling for joined, extensive knowledge in materials properties, engineering techniques and plasma physics. In this work, we propose a novel patterning procedure of self-supported 10 μm thick Au and Cu foils for obtaining micrometre-sized periodic gratings as targets for high-power laser applications. Accessible techniques were considered, by using cold rolling, electronbeam lithography and the Ar-ion milling process. The developed patterning procedure allows efficient control of the grating and foil surface on large area. Targets consisting of patterned regions of 450 μm × 450 μm, with 2 μm periodic gratings, were prepared on 25 mm × 25 mm Au and Cu free-standing foils, and preliminary investigations of the microtargets interacting with an ultrashort, relativistic laser pulse were performed. These test experiments demonstrated that,in certain conditions, the micro-gratings show enhanced laser energy absorption and higher efficiency in accelerating charge particle beams compared with planar thin foils of similar thickness.

Design and synthesis of novel coumarin analogs and their nematicidal activity against five phytonematodes

The presence of hydroxyl groups at the C4 and C7 positions in coumarin backbone has been proposed as a potential modification site for providing excellent bioactivity according to previous studies. A series of novel coumarin derivatives were rationally designed and synthesized by use of a complex catalytic system for a targeted modification at the above sites. These derivatives were assayed for nematicidal activity. As predicted, the derivatization enhanced the activity of the coumarins against five nematodes.Compounds 7b, 9a, 10 c and 11 c showed significant strong nematicidal broad spectrum activity against all tested nematodes. Compound 10 c was the most effective with the lowest LC50 values against Meloidogyne incognita（5.1 mmol/L）, Ditylenchus destructor（3.7 mmol/L）, Bursaphelenchus mucronatus（6.4 mmol/L）, Bursaphelenchus B. xylophilus（2.5 mmol/L） and Aphelenchoides besseyi（3.1 mmol/L）,respectively. A brief investigation on the structure–activity relationships（SAR） revealed that the targeted modification by a C7 hydroxyl was optimum compared with that of a C4 hydroxyl and that the coupling chain length was crucial for the nematicidal activity.