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Optimal pressure-sensitive cuts for surface acoustic waves on langasite

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Science in China(Series F) 2006年第2期49卷 254-261页

作者： han tao JI Xiaojun SHI Wenkang School of Electronic Information and Electrical Engineering Shanghai Jiaotong University Shanghai200240 China

The crystal langasite manifests its unique advantages and potentials for high temperature applications due to a high electromechanical coupling coefficient, temperature compensated orientations for surface acoustic wave （SAW）, and temperature stability. In order to analyze the pressure-induced frequency shift in SAW resonator type sensors at high temperature, this paper presents the electroelastic wave equations employing the effective material constants for small vibrations superimposed on biases originated from homogeneous temperature and external pressure fields in the Lagrangian description. Incorporated with the first-order perturbation integration, a model including both the mechanical and electrical perturbation items originating from thermal biases and small pressure fields is proposed. This universal model is suitable for substrate with high piezoelectricity and can be applied at either room temperature or high temperature circumstance. The criteria of optimal cuts for SAW pressure sensitivity, i.e., high electromechanical coupling coefficient and low temperature coefficient of delay, are proposed. A thorough investigation in trebly rotated cuts has shown that optimal pressure sensitive crystallographic areas can be obtained. The areas suitable for pressure sensors at room temperature are defined with Euler angles Ω1： φ=0°-0.6°, θ=144.4°-145.8°, ψ =23.2°-24.1°,Ω2： φ=59.4°-61.°, θ=34.2°-36.2°, ψ =24.1°-22.3°,Ω3： φ=119°-120°, θ=143.8°-145.5°, ψ =22.3°-23.5° The areas suitable for pressure sensors at high temperature are defined with Euler angles Ⅰ： φ=8°-30°, θ=24°-36°, ψ =4°-25°Ⅱ： φ=30°-55°, θ=144.4°-158°, ψ =4°-28° A set of experiments employing LGS （0, 150°, 22°） and （0, 90°, 0） has been performed to check the validity of the proposed calculation. The experimental relative sensitivity is in excellent agreement with the theoretical results.

关键词： surface acoustic wave langasite pressure sensitivity high temperature.

Simulating experiment on the enrichment of precious metals in Lower Cambrian black shale series of Hunan and Guizhou provinces

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Chinese Journal Of Geochemistry 2011年第3期30卷 375-381页

作者： han tao ZHU Xiaoqing LI Zengsheng The State Key Laboratory of Ore Deposzt Geochemtstry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

Adsorption experiments were made at room temperature and neutral pH value on different types of min-erals associated with the Lower Cambrian black shale series polymetallic layers in Hunan and Guizhou provinces on nanometer-sized Pt colloids and PtCl42--bearing ionic solutions with an attempt to constrain the relationship between the different types of minerals in the polymetallic layers and the enrichment of platinum group elements (PGEs). Experimental results showed that the different types of minerals show strong selectivity to the adsorption of nano-meter-sized Pt colloids and PtCl42--bearing ionic solutions. Metallic sulfides, organic matter and clay minerals are the strong adsorbents of PGEs, while quartz, albite, muscovite and other silicate minerals show a week adsorbility to both of them. This phenomenon is well consistent with the geological fact that metallic sulfides, organic matter and clay minerals in the polymetallic layers of the black shale series are the major carrier minerals of PGEs, giving a thorough explanation to the mechanism of enrichment of previous metal elements. Adsorption may be a principal mechanism of enrichment of precious metal elements under lower temperature conditions. The presence of the aforementioned strong adsorbents is the good geochemical barriers for the enrichment of PGEs.

关键词：黑色岩系金属富集模拟实验下寒武统贵州湖南铂族元素金属硫化物

The occurrence of gold in pyrite from the Liulincha gold ore belt,western Hunan Province,China

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Chinese Journal Of Geochemistry 2013年第4期32卷 392-397页

作者： LI Zengsheng ZHU Xiaoqing LU Huanzhang han tao State Key Laboratory of Ore Deposit Geochemistry Institute of GeochemistryChinese Academy of Sciences University of Chinese Academy of Sciences University of Quebec at Chicoutimi

In this study,an electron microprobe analyzer(EMPA) was used to map the spatial distribution and the occurrence of invisible gold in pyrite from the Liulincha gold ore *** data show that gold mainly occurs as submicroscopic-microscopic *** the contrast of the major guide elements of pyrite from the Liulincha gold ore belt and those from four hydrothermal-type gold deposits in the Jiaodong region,we can see the pyrites were formed in two stages:the pyrite from wall rock is mainly sedimentogenic,with simple structure;and the pyrite from ore body experienced early sedimentary process to late hydrothermal activity,the pyrite is regular in crystal form and exhibits fractured structure.

关键词：黄铁矿金矿带湖南省电子探针分析西部中国断裂结构空间分布

Embrittlement and toughening in CGHAZ of ASTM4130 steel

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Science China(Physics,Mechanics & Astronomy) 2011年第8期54卷 1447-1454页

作者： LI LiYing WANG Yong han tao LI ChaoWen College of Mechanical and Electronic Engineering China University of Petroleum Dongying 257061 China

In the present investigation, a thermal welding simulation technique was used to investigate the mechanical properties and microstructure features of the coarse-grained heat-affected zone (CGHAZ) of ASTM4130 steel. The effect of post welding heat treatment (PWHT) and welding heat inputs on the toughness of CGHAZ was also analyzed. The results show that CGHAZ has the lowest toughness, which is only 5.5%-7.1% of the base metal. CGHAZ is mainly composed of dislocation martensite, up-per and lower bainite, and M-A constituents. But after PWHT, carbides precipitate from non-equilibrium microstructures of CGHAZ accompanying some retained austenite which transforms into low bainite, thereby enhancing toughness over the base metal. Therefore, the key microstructure factors affecting fracture toughness are lathlike non-equilibrium microstructure and lowered supersaturation before and after PWHT respectively. When welding heat input is between 12 kJ/cm and 28 kJ/cm, the mechanical properties in CGHAZ of ASTM4130 with single-pass welding can satisfy the requirements when PWHT is applied.

关键词： ASTM4130 steel coarse-grained heat-affected zone embrittlement toughening

Occurrence modes of silver in the Ni-Mo-PGE polymetallic layer of the Lower Cambrian black shales in Zunyi, Guizhou Province, South China

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Chinese Journal Of Geochemistry 2014年第4期33卷 387-392页

作者： han tao ZHU Xiaoqing LIU Shirong LI Xiaoxia State Key Laboratory of Ore Deposit Geochemistry Institute of Geochemistry Chinese Academy of Sciences University of Chinese Academy of Sciences

The Ni-Mo-PGE polymetallic mineralization of the Lower Cambrian black shales locate in Zunyi, South China and contain abundant noble metals such as Ag, Au and PGE, and especially Ag with average concentration of 64×10-6. The occurrence modes of Ag have been investigated using methods of selective chemical dissolution and transmission electron microscopy. The results demonstrate that the occurrence modes of Ag are complex and diversiform. It might be associated with clay minerals, organic matter, sulfides and also occurred as native silver and sulfides with nanometer in size. Combined with results of previous studies, we suggest that the sulfides, clay minerals and organic matter which hosted in the Ni-Mo-PGE polymetallic ores of black shales can play the roles of important reduction and adsorption geochemical barriers for the enrichment and distribution of silver. This study further implies that the selective chemical dissolution and transmission electron microscopy may pave the way to study the occurrence modes of other noble metals in black shales.

关键词：多金属矿化黑色页岩下寒武统中国南方 PGE 白银镍钼遵义

Stego key searching for LSB steganography on JPEG decompressed image

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Science China(Information Sciences) 2016年第3期59卷 60-74页

作者： Jiufen LIU Yuguo TIAN tao han Junchao WANG Xiangyang LUO Zhengzhou Information Science and Technology Institute State Key Laboratory of Mathematical Engineering and Advanced Computing

At present, steganalysis research focuses on detecting the existence of a hidden message. However,extracting the hidden information, i.e., an extracting attack, is crucial in obtaining effective evidence in computer forensics. Due to the difficulty of an extracting attack, research in this field is limited. In steganography with a stego key, an extracting attack is equivalent to recovering the stego key. In this paper we study a method for recovering the stego key in least significant bit(LSB) steganography with a decompressed JPEG image as the cover image. Firstly, the recovery of the stego key is translated into a cryptanalysis problem for a sequential cipher. The method for recovering the stego key is based on estimating the modification positions. The minimum size of the data used to recover the stego key successfully is discussed. Secondly, when a decompressed JPEG image is used as the cover image, the probability of recovering the cover pixels using recompression is *** is used to compute the error of the estimated sequence. Finally, an algorithm to recover the stego key in LSB steganography with a decompressed JPEG image as the cover image is proposed. The experimental results for the steganographic software, Hide and Seek 4.1 and its variant, which is a typical representative of LSB steganography, show that the proposed method can successfully recover the stego key in LSB replacement and LSB matching, i.e., the extracting attack is successful, and it outperforms three previous methods in terms of computational complexity.

关键词： steganalysis extracting attack LSB steganography decompressed JPEG image recompression stego key

Cathepsin B-responsive nanodrug delivery systems for precise diagnosis and targeted therapy of malignant tumors

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Chinese Chemical Letters 2020年第12期31卷 3027-3040页

作者： Yanan Li Ting Mei Shupeng han tao han Yongbing Sun Hui Zhang Feifei An Department of Radiology First Hospital of Shanxi Medical UniversityTaiyuan 030001China College of Medical Imaging Shanxi Medical UniversityTaiyuan 030001China Institute of Medical Engineering Department of Biophysicschool of Basic Medical ScienceHeatih Science Center Xi'an Jiaotong UniverstyXi'an 710061China College of Chemistry and Life Science Institute of Functional MoleculesChengdu Normal UniversityChengdu 611130China Division of Pharmaceutics National Pharmaceutical Engineering Center for Solid Preparation in Chinese Hierbal MedicimeJiamgpri Unverity of Truditional Chinese MedicinveNanchang 330006China

The tumor microenvironment(TME)significantly influences cancer evolution and therapeutic *** biofunctional molecules to the TME has long been appreciated as a means of raising local drug concentrations and reducing systemic *** booming nanotechnology field has realized the importance of cathepsin B to derive a variety of intelligent enzyme-responsive nanosized drug delivery systems(nanoDDS)to improve treatment responses and clinical *** this tutorial review,after introducing the molecular structure and physiological/pathological functions of cathepsin B,the outstanding achievements of cathepsin B-responsive nanoplatforms in the precise diagnosis,targeted therapy,and synergistic theranostics of malignant tumors are systematically ***,the challenges of enzyme-substrate incompatibility,low diagnostic sensitivity,mass production and biocompatibility of multifunctional nanoDDS are considered in order to successfully promote them to clinical applications.

关键词： Tumor microenvironment Cathepsin B Theranostics Precise diagnosis Targeted therapy

Feasibility of medical radioisotope production based on the proton beams at China Spallation Neutron Source

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Nuclear Science and Techniques 2024年第6期35卷 26-39页

作者： Bing Jiang Bin-Bin Tian han-tao Jing Qi-Fan Dong Spallation Neutron Source Science Center Dongguan 523803China Institute of High Energy Physics Chinese Academy of Sciences(CAS)Beijing 100049China University of Chinese Academy of Sciences Beijing 100049China

The utilization of a proton beam from the China Spallation Neutron Source(CSNS)for producing medical radioisotopes is appealing owing to its high current intensity and high *** medical isotope production based on the proton beam at the CSNS is significant for the development of future radiopharmaceuticals,particularly for theα-emitting *** production yield and activity of typical medical isotopes were estimated using the FLUKA *** results indicate that the 300-MeV proton beam with a power of 100 kW at CSNS-II is highly suitable for proof-of-principle studies of most medical *** particular,this proton beam offers tremendous advantages for the large-scale production of alpha radioisotopes,such as 225Ac,whose theoretical production yield can reach approximately 57 Ci/*** on these results,we provide perspectives on the use of CSNS proton beams to produce radioisotopes for medical applications.

关键词： CSNS proton beam Medical isotope production α-Emitting radionuclides Nuclidic purity analysis

Numerical simulation of coupling heat transfer and thermal stress for spent fuel dry storage cask with different power distribution and tilt angles

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Nuclear Science and Techniques 2023年第2期34卷 109-127页

作者： Wei‑Hao Ji Jian‑Jie Cheng han‑Zhong tao Wei Li College of Urban Construction Nanjing Tech UniversityNanjing 211800China School of Energy Science and Engineering Nanjing Tech UniversityNanjing 211800China

Dry storage containers must be secured and reliable during long-term storage,and the effect of decay heat released from the internal spent fuel on the cask has become an important research *** this paper,a 3D computational fluid dynamics model is presented,and the accuracy of the calculation is verified,with computational errors of less than 6.2%.The thermal stress of the dry storage cask was estimated by coupling it with a transient temperature *** total power remained constant and adjusting the power ratio of the inner and outer zones had a small effect on the stress results,with a maximum equivalent stress of approximately 5.2 kPa,which occurred at the lower edge of the *** the case of tilt,the temperature gradient varied in a wavy distribution,and the wave crest moved from right to *** the tilt angle affects the air distribution in the annular gap,leading to the shell temperature being transformed,with a maximum equivalent stress of 202 MPa at the bottom of the ***,the equivalent stress in both cases was less than the yield stress(205 MPa).

关键词： Thermal stress CFD simulation Spent nuclear fuel Dry storage cask