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      • Large-scale Landslides in Diexi Region of Minjiang River, Sichuan Province, China

        ( Yunsheng Wang ),( Bo Zhao ),( Xun Zhao ),( Qianqian Feng ),( Fengshuang Guo ),( Yue Luo ),( Jiangwei Liu ) 대한지질공학회 2019 대한지질공학회 학술발표회논문집 Vol.2019 No.2

        The field survey regarding large-scale landslide (Scale) of whole Minjiang River shows that Diexi region, located in upper reach of Minjiang River, is an obvious large-scale landslide concentration area. There are 21 large-scale landslides in Diexi region, and 70% landslides belong to super large-scale landslides (Scale), as shown in Figure 1. All these landslides both blocked rivers and some barrier lakes still exist. Based on field investigations, the failure mechanism and geological environment are discussed in this study. For failure mechanism, three fracture planes cut the rock mass into separation; the stepped fractures forms slip surfaces; finally, these unstable rock mass slide. For geological environment, Diexi region is in west boundary of Minshan block, and in the N-S seismic belt and the Jiaochang arc tectonic belt, two active fractures (Songpinggou fracture and Minjiang fracture) confluence at Diexi region; all these make Diexi region be a Knick point of Minjiang River, a compression and torsion zone and a high stress concentration zone. Intensive uplift and quick incision (1.88 mm/yr.) since the middle Pleistocene formed a gorge with sharp slopes and strong lateral uploading. For failure cause, the intensive tectonic activities make the rock mass produce many fractures, numerous strong earthquakes weaken the rock mass integrity further; finally, the strong earthquake triggered them.

      • KCI등재

        Reversible Coordinative Chain Transfer Polymerization of Butadiene Using a Neodymium Phosphonate Catalyst

        Zhengwei Tang,Aimin Liang,Handong Liang,Jiangwei Zhao,Lin Xu,Jie Zhang 한국고분자학회 2019 Macromolecular Research Vol.27 No.8

        This study involves an investigation of the chain transfer reaction of butadiene (Bd) polymerization, under the neodymium tris[bis(2-ethylhexyl)phosphate] (Nd)/diisobutyl aluminum hydride (Al)/ethylaluminum sesquichloride (Cl)/Bd catalytic system. The results show that the chain transfer reaction itself is reversible. Only chain propagation and chain exchange reactions occurred during the later period of polymerization, and there was a linear relationship between the molecular weight and the conversion rate. All polymer chains showed sufficient reactivity to propagate by reacting with the monomer. The degree of the chain transfer reaction can be determined by the amount of Al, and the molecular weight in the synthetic polybutadiene can be accurately designed by the formula Mn=54·Bd/Nd/(0.67Al/Nd-7.17). The catalyst-polymerized butadiene afforded products featuring a relatively narrow molecular weight distribution and a high cis-1,4 stereospecificity. One of these products, polybutadiene rubber, showed narrow distribution in the sample, and exhibited good physical and mechanical properties, low abrasion, and low rolling resistance.

      • KCI등재

        Genome-wide identification of drought-responsive microRNAs and their target genes in Chinese jujube by deep sequencing

        Zhang Luhe,Li Yi,Yang Jiangwei,Huang Huali,Lu Qian,Zhao Junying,Wang Fang,Wang Duofeng 한국유전학회 2023 Genes & Genomics Vol.45 No.2

        Background MicroRNAs (miRNAs) are about 21 snucleotide (nt) long, non-coding RNAs that play an important role in plant abiotic stress responses. Chinese jujube is a native fruit tree in China, which is also an admittedly drought-resistant plant. But the drought-related miRNAs have little been reported in jujube. Objective To identify possibly drought-responsive microRNAs and their target genes in Chinese Jujube. Methods Twelve small RNA libraries were constructed from two jujube genotypes both drought treated and control samples with three replicates to identify known and novel miRNAs in Chinese Jujube, DESeq2 was used to identify expression pattern of miRNAs between drought treatment and control samples, TargetFinder program was used to predict potential target genes of conserved and novel miRNAs, RT-qPCR were used to analysis the expression levels of drought-related miRNAs and their potential targets. The RNA ligase-mediated RLM-5′ RACE experiments were performed to validate predicted target genes of drought-related miRNAs. Results 43 known miRNAs and 431 novel miRNAs were identified in Chinese jujube. Expression analysis showed that 28 miRNAs were differential expressed under drought stress in jujube variety “Dongzao”, including 21 up-regulated miRNAs and 7 down-regulated miRNAs, 61 miRNAs were differential expressed under drought stress in Chinese jujube variety “Zanhuangdazao”, including 23 up-regulated miRNAs and 37 down-regulated miRNAs. Depend on miRNAs target prediction, functional annotation and expression analysis, we identified 9 drought-related miRNAs, and 7 target genes of 6 miRNAs were confirmed using the modified 5′-RACE method. Also, RT-qPCR analyses revealed that relative expression of those miRNAs and their targets have negative tendency. Conclusion We identified 6 drought-related miRNAs by high-throughout sequencing and target gene annotation from Chinese jujube, and targets of those miRNAs were confirmed by the modified 5′-RACE method. These findings provide molecular evidence for enhancing drought tolerance in Chinese jujube and other plants.

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        Acoustic system design and experimental research on the ultrasonic forming grinding gear

        Xiao-bo Wang,Mingqiang Wu,Jiangwei Jin,Bo Zhao 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.8

        In order to obtain high-performance gear elements with integrated shape, using non-resonant theory, the gear grinding experiment and ultrasound-assisted grinding acoustic system were established. Firstly, a theoretical model founded on the non-resonant proposed methodology was constructed. The frequency equation and displacement characteristics of the vibration system were established based on the specified boundary conditions, and the geometric size of the ultrasonic amplitude with a design frequency of 20 kHz was established. The acoustic system was simulated employing finite element software, and the analysis revealed that its frequency range was 19648 Hz, which was consistent with the design outcome. Meanwhile, the amplitude of the end surface of the tool gear reaches 5.59 μm, and the vibration was stable. Secondly, according to the solution of geometric parameters, the acoustic performance test was carried out. The error between resonant frequency (20387 Hz) and design frequency was 1.93 %, and the amplitude was 4.5 μm, which met the requirements of ultrasonic assisted grinding gear. Finally, the grinding test was carried out. The study results show that compared to conventional gear grinding, ultrasonic supported grinding lessens the grinding force by 11.5 % to 35.4 % and, at most, lowers the grinding temperature by 22.5 %.

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