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Strength characteristics of rock anchored by NPR bolt with different preloads

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Journal of Mountain Science 2023年第3期20卷 834-844页

作者： SUN Xiao-ming CUI Li ZHANG Yong WANG Lei jiang ming State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and Technology(Beijing)Beijing 100083China School of Mechanics and Civil Engineering China University of Mining and Technology(Beijing)Beijing 100083China

This study compares the strength characteristics of rocks anchored by NPR bolts and ordinary bolts with varied preloads,based on the mechanical properties of NPR bolts(with a negative Poisson’s ratio).The results show that the uniaxial compressive stress-strain curve of ordinary anchored rocks exhibits noticeable abrupt *** reaching peak strength,the bolt breaks,whereas the stress-strain curve of NPR-anchored rocks is *** NPR bolt enters the stage of continuous resistance after reaching maximal strength and does not *** the preload increases,the strength of the anchored rock grows linearly.A calculation equation for the strength of the anchored rock is proposed based on the *** theoretical equation fits the test results well,and the fitted parameters show that NPR bolts can better increase the strength of the *** concept of dynamic toughness UC of anchored rock is proposed to reflect the comprehensive mechanical properties of anchored rock,including strength and *** the preload increases,the UC of ordinary anchored rock first decreases and then increases,while the UC of the NPR anchored rock does not change significantly with the preload when the strain is small,and the UC increases with the increase of the preload when the strain is large.

关键词： NPR bolt Anchored rock Rock bolt Uniaxial compression Preload Strength characteristics

A Facile Stereospecific Synthesis of 1, 3-Enynylsulfides via Sonogashira Coupling of （E）-a-Iodovinyl Sulfides with 1-Alkynes

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Chinese Chemical Letters 2006年第6期17卷 757-760页

作者： Jian Wen jiang ming Zhong CAI Department of Chemistry Jiangxi Normal University Nanchang 330027

（E）-α-Iodovinyl sulfides 1 underwent the Sonogashira coupling reactions with terminal alkynes 2 in piperidine at room temperature in the presence of 5 mol % of Pd（PPh3）4 and 10 mol % of CuI to afford the correspo... 详细信息

关键词： (E)-α-Iodovinyl sulfide 1 3-enynylsulfide Sonogashira coupling terminal alkyne.

Structural Analysis of Water-soluble Polysaccharide PIP_1 Extracted from the Cultured Mycelium of Phellinus igniarius

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Chemical Research in Chinese Universities 2006年第6期22卷 708-711页

作者： WU ming-jiang jiang De-zhi LIU Tie-mei ZHANG Li-ping School of Life Science Northeast Normal University Changchun 130024 P. R. China School of Life and Environment Science Wenzhou University Wenzhou 325035 P.R. China

Water-soluble crude polyseccharide（PIP） was extracted from cultured mycelium of the fungus Phellinus igniarius. After ethanol precipitation and sepharose CL-6B gel filtration, the fraction of PIP1 was obtained, which was shown to be a homogeneous polysaccharide by means of high-performance liquid chromatography. The structure of PIPt was determined by using several methods. C.,C analysis indicates that PIP1 is composed of the monosaccharides of glucose, galactose, and mannose. Their malar ratio is 3. 70： 4. 06： 1.00. The molar weight was estimated to be 17 kd via HPLC. IR, GC, partial hydrolysis with acid, pefiedate oxidation, Smith degradation, methylation, and GC-MS analysis were used for the structural analyses of PIP1. The results show that PIP1 has a small quantity of branch structure, The main glycosidic linkage of PIP1 has a β-configurafion. The main chain is made up of a large mass of glucose （ 1→3 ） and few mannose （ 1→4 ） ; the side chain is composed of glucose （ 1 →3 ） and galactose （ 1→6 ） ; the nonreduced end is composed of galactose and glucose. The side chains are branched at 6-0 of glucose（ 1→3,6） and mannose（1→4,6）. On an average, there are three branches among 20 residues. It is presumable that the existence of 1,3-linked Glc in the main and side chains is the main reason for its higher antitumor activity.

关键词： Phellinus igniarus Cultured mycelium Polysaccharide Structural analysis

Growth mechanism for zinc coatings deposited by vacuum thermal evaporation

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Journal of Iron and Steel Research International 2021年第8期28卷 1047-1053页

作者： Xiao-pan Qiu Xin Liu She-ming jiang Guang-rui jiang Qi-fu Zhang National Engineering Laboratory of Advanced Coating Technology for Metals Central Iron and Steel Research InstituteBeijing 100081China Beijing Key Laboratory of Green Recyclable Process for Iron and Steel Production Technology Shougang Group Co.Ltd.Research Institute of TechnologyBeijing 100043China

The vacuum thermal evaporation technique was used to simultaneously deposit zinc coatings onto interstitial free steel plates and single-crystal silicon wafers in a high vacuum *** effect of substrate temperature on the mor-phology and crystal orientation of zinc coatings was *** the substrate temperature was 25 and 50℃,the zinc crystallites were plate-like and grew under a particular angle to the substrate *** the substrate was heated to 100℃,the zinc crystallites were regular hexagonal and arranged almost parallel to the substrate *** addition,observation of pure zinc coatings with different thicknesses showed that the growth of zinc coating was mainly in the Volmer-Weber *** the process parameters were appropriate,the zinc coating was composed of closely arranged columnar crystallites,and the crystallites grew preferentially along[0001]direction.

关键词： Vacuum thermal evaporation Zinc coating Deposition temperature Growth mechanism

Overexpression of a Broccoli Defensin Gene BoDFN Enhances Downy Mildew Resistance

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Journal of Integrative Agriculture 2012年第7期11卷 1137-1144页

作者： jiang ming HE Cai-ming MIAO Li-xiang ZHANG Yu-chao College of Life Science Taizhou University Linhai 317000 P.R.China Institute of Horticulture Zhejiang Academy of Agricultural Science Hangzhou 310021 P.R. China

Plant defensins are small, basic cysteine-rich peptides that play important roles in disease resistance. A gene, designated BoDFN, was isolated from Brassica oleracea var. italica. Gene sequence has been submitted to NCBI with an accession no. of HQ436486. Complete coding sequence of BoDFN is 243 bp in length encoding 80 amino acids. Sequence comparison results showed that BoDFN shared high homology with those of crucifer plants and there were only few DNA base differences. RT-PCR results indicated an increase of gene expression in Hyaloperonospora parasitica infected leaves and revealed a significant increase at 24 and 36 h of treatment. A recombinant plasmid, named pBI121-BoDFN, was constructed and introduced into Agrobacterium tumefacien LBA4404. PCR screening for 65 regenerated plantlets, 17 positive plantlets were obtained, PCR screening results revealed that 17 out of 65 regenerated plantlets were positive. Disease resistant identification results indicated that all positive plants showed an increase in resistance to H. parasitica.

关键词： broccoli downy mildew defensin overexpression

Low Bit Rate Underwater Video Image Compression and Coding Method Based on Wavelet Decomposition

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China Communications 2020年第9期17卷 210-219页

作者： Yonggang He Xiongzhu Bu ming jiang Maojun Fan Nanjing University of Science&Technology Nanjing 210094China The Third Research Institute of China Electronics Technology Corporation Beijing 100015China

In view of the limited bandwidth of underwater video image transmission,a low bit rate underwater video compression coding method is *** on the preprocessing process of wavelet transform and coefficient down-sampling,the visual redundancy of underwater image is removed and the computational coefficients and coding bits are *** the same time,combined with multi-level wavelet decomposition,inter frame motion compensation,entropy coding and other methods,according to the characteristics of different types of frame image data,reduce the number of calculations and improve the coding *** experimental results show that the reconstructed image quality can meet the visual requirements,and the average compression ratio of underwater video can meet the requirements of underwater acoustic channel transmission rate.

关键词： low bit rate down-sampling wavelet decomposition underwater video coding

Crevice Corrosion Behaviors Between CFRP and Stainless Steel 316L for Automotive Applications

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Acta Metallurgica Sinica(English Letters) 2019年第10期32卷 1219-1226页

作者： Xia-Yu Wu Jia-Kun Sun Jia-ming Wang Yi-ming jiang Jin Li Department of Materials Science Fudan University

Carbon fiber reinforced plastics (CFRP) are promising lightweight materials for vehicle applications. 316L is one of the most widely used types of austenite stainless steels and applied in lots of automotive applications. The existence of crevices will result in galvanic corrosion and crevice corrosion when CFRPs and 316L are directly connected. A crevice former for the galvanic system was therefore designed and applied to evaluate the crevice corrosion behaviors and study the mechanism of galvanic crevice corrosion through several electrochemical techniques in this research. The results showed that the crevice corrosion of galvanic systems grew from crevice mouth to the inside crevice and could be divided into four steps, metastable pitting corrosion at the crevice mouth, initiating step of crevice corrosion, propagating step and ending step of crevice corrosion. Because of the influences of the galvanic system, electrode reaction rates were speeded up and the passivation region was shortened at the initiating stage of crevice corrosion. Corrosion rate was observed to be higher in the galvanic system than that in normal crevice systems.

关键词： Crevice corrosion Galvanic system Carbon fiber reinforced plastics 316L stainless steels

pH-Sensitive Wettability Induced by Topological and Chemical Transition on the Self Assembled Surface of Block Copolymer

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Chinese Journal of Polymer Science 2014年第1期32卷 92-97页

作者： Zhi Geng Song Guan He-ming jiang 高龙成 Zhi-wen Liu Lei jiang Key Laboratory of Bio-inspired Smart Interfacial Science and Technology of Ministry of Education School of Chemistry and Environment BeiHang University Agilent Technologies Beijing National Laboratory for Molecular Sciences (BNLMS) Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences

pH-sensitive wettability of polystyrene-b-poly（4-vinylpyridine）（PS-b-P4VP） self assembled films, exhibiting superoleophobicity under water and hydrophilicity at low pH value, and oleophobicity under water and hydrophobicity at neutral condition, has been realized. The wettability properties resulted from the surface topological and chemical transition, which were confirmed by in situ AFM measurements under water at different pH. At low pH, P4VP chains, which were confined in the hexagonal-packed nanodomains, got protonated into a swollen state, while at high pH, P4VP chains were deprotonated into a collapsed state. The reversible protonation/deprotonation procedure on the molecular scale leads to surface topological and chemical transition, thereby pH-sensitive wettability.

关键词： Block copolymer Wettability pH sensitive Self assembly.

Surface grain refinement mechanism of SMA490BW steel cross joints by ultrasonic impact treatment

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International Journal of Minerals,Metallurgy and Materials 2017年第4期24卷 410-414页

作者： Bo-lin He Lei Xiong ming-ming jiang Ying-xia Yu Li Li School of Mechanical & Electronic Engineering East China Jiaotong University Nanchang 330013 China

Ultrasonic impact treatment (UIT) is a postweld technique for improving the fatigue strength of welded joints. This technique makes use of ultrasonic vibration to impact and plastically deform a weld toe and can achieve surface grain refinement of the weld toe, which is considered as the main reason for the improvement of fatigue strength. In this paper, the microstructure of the surface of a treated weld toe was observed by metallographic microscopy and transmission electron microscopy (TEM). The results show that UIT could produce severe plastic deformation on the surface layer of the weld toe and the maximum depth of plastic deformation extended to approximately 260 μm beneath the treated surface. Repeated processing could exacerbate the plastic deformation on the surface layer, resulting in finer grains. We can conclude that the surface grain refinement mechanism of SMA490BW welded joints is related to the high density of dislocation tangles and dislocation walls. © 2017, University of Science and Technology Beijing and Springer-Verlag Berlin Heidelberg.

关键词： Grain size and shape High resolution transmission electron microscopy Joints (structural components) Plastic deformation Transmission electron microscopy Ultrasonic applications Ultrasonic effects Weathering steel Welding Welds