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      • KCI등재

        Simulated altitude exercise training damages small intestinal mucosa barrier in the rats

        Li, Meng,Han, Tianyu,Zhang, Weijia,Li, Wei,Hu, Yang,Lee, Sang Ki Korean Society of Exercise Rehabilitation 2018 JER Vol.14 No.3

        <P>This study investigated the effect of simulated altitude training on the changes of small intestinal mucosa barrier, bacterial overgrowth and inflammatory response in the small intestine of rat. Male 8-week-old Sprague-Dawley rats were randomly divided into four groups: normal oxygen sedentary group (n=30), normal oxygen exercise group (n=30), low oxygen sedentary group (n=30) and low oxygen exercise group (n=30). Exercise training was on a treadmill for 1 hr per day on days 3, 6, and 9 in the hypoxia condition. Hematological profiles, hematolxylin and eosin staining, fluorescence <I>in situ</I> hybridization, reverse transcription-polymerase chain reaction and Western blot were used to analyze the effect of simulated altitude training on the amount of bacteria, and expression of mRNA and protein. Simulated exercise training significantly increased red blood cells and hematocrit. The small intestinal mucosa barrier was significantly injured by the simulated altitude exercise training. Comparatively more bacterial growth was evident in the small intestine by the simulated altitude exercise training. mRNA levels of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) and protein expression of nuclear factor-kappa B (NF-κB) were significantly elevated by simulated altitude exercise training. These results suggest that the simulated altitude exercise training may impair the small intestinal mucosa barrier via elevation of bacterial growth and inflammatory cytokines (IL-6, TNF-α) and the up-regulation of NF-κB in the rats.</P>

      • KCI등재

        Seismic Performance of Welded Steel Beam-to-Column Connections with Initial Weld Defects

        Jiaming Li,Haoran Yu,Weibin Li,Weijia Cheng 한국강구조학회 2022 International Journal of Steel Structures Vol.22 No.2

        Based on the research of steel structures destroyed in earthquakes, it is often found that brittle fractures of the bottom beam fl anges of welded beam-to-column connections are caused by welding defects. In this study, artifi cial surface notches in the welds of single beam fl anges were prepared, and four experimental specimens of welded steel beam-to-column connections were tested to explore the eff ects of the initial crack and three diff erent connection types on the seismic performance of the connections. Through extended fi nite element methods, the factor of the depth of the initial crack was discussed. The results showed that the fracture mode and the rate and location of crack propagation are signifi cantly changed, and the seismic performance of the connections is reduced when there is an initial crack existing in the weld of a single beam fl ange. The fracture in box beam to box column connections shows brittle failure regardless of the initial crack, but the depth of the initial crack has the least infl uence on their seismic performance among the three connection types. The seismic performance of H-shaped beam to H-shaped column connections is the most sensitive to the depth of the initial crack. It should be noted that the weld quality of steel beam-to-column connections, especially the connections with H-shaped columns, should be carefully checked and monitored during the welding construction process and after earthquakes to ensure the bearing and deformation capacities meeting the requirements.

      • KCI등재

        Seismic wave propagation through surface basalts – implications for coal seismic surveys

        Weijia Sun,Binzhong Zhou,Peter Hatherly,Li-Yun Fu 한국지구물리.물리탐사학회 2010 지구물리와 물리탐사 Vol.13 No.1

        Seismic reflection surveying is one of the most widely used and effective techniques for coal seam structure delineation and risk mitigation for underground longwall mining. However, the ability of the method can be compromised by the presence of volcanic cover. This problem arises within parts of the Bowen and Sydney Basins of Australia and seismic surveying can be unsuccessful. As a consequence, such areas are less attractive for coal mining. Techniques to improve the success of seismic surveying over basalt flows are needed. In this paper, we use elastic wave-equation-based forward modelling techniques to investigate the effects and characteristics of seismic wave propagation under different settings involving changes in basalt properties, its thickness,lateral extent, relative position to the shot position and various forms of inhomogeneity. The modelling results suggests that:1) basalts with high impedance contrasts and multiple flows generate strong multiples and weak reflectors; 2) thin basalts have less effect than thick basalts; 3) partial basalt cover has less effect than full basalt cover; 4) low frequency seismic waves (especially at large offsets) have better penetration through the basalt than high frequency waves; and 5) the deeper the coal seams are below basalts of limited extent, the less influence the basalts will have on the wave propagation. In addition to providing insights into the issues that arise when seismic surveying under basalts, these observations suggest that careful management of seismic noise and the acquisition of long-offset seismic data with low-frequency geophones have the potential to improve the seismic results.

      • KCI등재후보

        Bandwidth-efficient Cooperative Diversity with Rotated Constellations and Its Performance Analysis

        ( Weijia Lei ),( Xiangming Li ),( Xianzhong Xie ) 한국인터넷정보학회 2010 KSII Transactions on Internet and Information Syst Vol.4 No.6

        Cooperative diversity is a technique with which a virtual multiple antenna array is established among the single antenna users of the wireless network to realize space diversity. Signal space diversity (SSD) is a bandwidth-efficient diversity technique, which uses constellation rotation and interleaving techniques to achieve diversity gain. A new cooperative diversity scheme with rotated constellations (RCCD) is proposed in this paper. In this scheme, data are modulated by using a rotated constellation, and the source and the relays transmit different components of the modulated symbols. Since any one of the components contains full information of the symbols, the destination can obtain multiple signals conveying the same information from different users. In this way, space diversity is achieved. The RCCD scheme inherits the advantage of SSD - being bandwidth-efficient but without the delay problem of SSD brought by interleaving. The symbol error rate of the RCCD scheme is analyzed and simulated. The analysis and simulation results show that the RCCD scheme can achieve full diversity order of two when the inter-user channel is good enough, and, with the same bandwidth efficiency, has a better performance than amplify-and-forward and detect-and-forward methods.

      • KCI등재

        Starch graft copolymer and polymer gel applied in Bohai oilfield for water plugging and profile control and their mechanisms

        Weijia Cao,Kun Xie,Xiaoyan Wang,Xiangguo Lu,Xin He,Guorui Xu,Xiang Li 한국자원공학회 2020 Geosystem engineering Vol.23 No.4

        Water plugging and profile control are becoming increasingly important in water-flooding oilfields. In this study, the experiments were conducted to determine the microscopic mechanisms and effects of water plugging, profile control, and ‘water plugging + profile control’. Initially, the starch graft copolymer and polymer gel used showed only slight changes in viscosity. However, within 12 h, the viscosities exceeded 100,000 mPa·s, which indicated that the two agents had good plugging effects. When the plugging agent was starch graft copolymer, the oil recovery with water plugging was 2% and 0.8% higher than the values for profile control with polymer gel on a heterogeneous core and parallel core, respectively. The recoveries with the ‘water plugging + profile control’ combination for the heterogeneous core and parallel core were 25.9% and 25.5%, respectively, which showed the superior enhanced oil recovery. The mechanism research showed that when the reservoir entered the middle and high water-cut development stages, the residual oil was mainly distributed in the middle- and low-permeability layers near the oil well. Thus, water plugging provided a greater increase in oil recovery. Under the actual demands of the Bohai oilfield, it would be better to adopt a combined water plugging and profile control operation.

      • KCI등재

        Seismic wave propagation through surface basalts - implications for coal seismic surveys

        Sun, Weijia,Zhou, Binzhong,Hatherly, Peter,Fu, Li-Yun Korean Society of Earth and Exploration Geophysici 2010 지구물리와 물리탐사 Vol.13 No.1

        Seismic reflection surveying is one of the most widely used and effective techniques for coal seam structure delineation and risk mitigation for underground longwall mining. However, the ability of the method can be compromised by the presence of volcanic cover. This problem arises within parts of the Bowen and Sydney Basins of Australia and seismic surveying can be unsuccessful. As a consequence, such areas are less attractive for coal mining. Techniques to improve the success of seismic surveying over basalt flows are needed. In this paper, we use elastic wave-equation-based forward modelling techniques to investigate the effects and characteristics of seismic wave propagation under different settings involving changes in basalt properties, its thickness, lateral extent, relative position to the shot position and various forms of inhomogeneity. The modelling results suggests that: 1) basalts with high impedance contrasts and multiple flows generate strong multiples and weak reflectors; 2) thin basalts have less effect than thick basalts; 3) partial basalt cover has less effect than full basalt cover; 4) low frequency seismic waves (especially at large offsets) have better penetration through the basalt than high frequency waves; and 5) the deeper the coal seams are below basalts of limited extent, the less influence the basalts will have on the wave propagation. In addition to providing insights into the issues that arise when seismic surveying under basalts, these observations suggest that careful management of seismic noise and the acquisition of long-offset seismic data with low-frequency geophones have the potential to improve the seismic results.

      • KCI등재

        Individualized Treatment of Allergic Rhinitis According to Nasal Cytology

        Jianjun Chen,Yue Zhou,Li Zhang,Yanjun Wang,Amber N. Pepper,Seong H. Cho,Weijia Kong 대한천식알레르기학회 2017 Allergy, Asthma & Immunology Research Vol.9 No.5

        Purpose: Nasal cytology is important in the diagnosis and treatment of nasal inflammatory diseases. Treatment of allergic rhinitis (AR) according to nasal cytology has not been fully studied. We plan to explore the individualized treatment of AR according to nasal cytology. Methods: Nasal cytology from 468 AR patients was examined for inflammatory cell quantity (grade 0-5) and the percentage of neutrophils and eosinophils. Results were subdivided into the following categories: AR(Eos), eosinophil ≥50% of the whole inflammatory cells; AR(Neu), neutrophils ≥90%; AR(Eos/Neu), 10%≤ eosinophil <50%; AR(Low), grade 0/1 inflammatory cell quantity. Nasal cytology-guided treatment was implemented: all AR(Eos) patients (n=22) and half of the AR(Neu) patients (AR[Neu1], n=22) were treated with mometasone furoate spray and oral loratadine. Another half of the AR(Neu) patients (AR[Neu2], n=22) were treated with oral clarithromycin. Visual analog scale (VAS), symptom scores, and nasal cytology were evaluated 2 weeks before and after treatment. Results: There were 224/468 (47.86%) AR(Eos), 67/468 (14.32%) AR(Neu), 112/468 (23.93%) AR(Eos/Neu), and 65/468 (13.89%) AR(Low) of the AR patients studied. There were no significant differences in clinical characteristics among these subgroups, except that the nasal blockage score was higher in AR(Eos) patients than in AR(Neu) patients (1.99 vs 1.50, P=0.02). Comparing AR(Eos) patients with AR(Neu1) patients 2 weeks after treatment, nasal symptoms and VAS were significantly lower in AR(Eos) patients, except for nasal blockage symptoms (P<0.05 of nasal itching and sneezing; P<0.01 for nasal secretion, total scores, and VAS). Comparing AR(Neu1) with AR(Neu2) patients, nasal symptoms, and VAS were significantly lower in AR(Neu2), except for nasal blockage and nasal itching symptoms (P<0.05 for nasal secretions, sneezing, total score, and VAS). Conclusions: Nasal cytology may have important value in subtyping AR and optimizing AR treatment. Treating neutrophils is very important in AR patients with locally predominant neutrophils.

      • KCI등재

        The Impacts of Childhood Trauma on Psychosocial Features in a Chinese Sample of Young Adults

        Dandan Wang,Shaojia Lu,Weijia Gao,Zhaoguo Wei,Jinfeng Duan,Shaohua Hu,Manli Huang,Yi Xu,Lingjiang Li 대한신경정신의학회 2018 PSYCHIATRY INVESTIGATION Vol.15 No.11

        Objective The aims of the present study were to explore the occurrence of childhood trauma and importantly to determine the impacts of childhood trauma on psychosocial features in a Chinese sample of young adults. Methods A survey was carried out in a group of 555 university students by using Childhood Trauma Questionnaire (CTQ), Self-rating Depression Scale (SDS), Self-rating Anxiety Scale (SAS), Dysfunctional Attitudes Questionnaire (DAS), Eysenck Personality Questionnaire (EPQ), and Social Support Rating Scale (SSRS). The moderate-severe cut-off scores for CTQ were used to calculate the prevalence of childhood trauma, and then psychosocial features were compared between individuals with and without childhood trauma. Results A proportion of 18.6% of university students had self-reported childhood trauma exposures. Subjects with childhood trauma reported higher scores of SDS, SAS, DAS, and psychoticism and neuroticism dimensions of EPQ (t=4.311–5.551, p<0.001); while lower scores of SSRS and extraversion dimension of EPQ (t=-4.061– -3.039, p<0.01). Regression analyses further revealed that scores of SAS and DAS were positively (Adjusted B=0.211–0.230, p<0.05), while scores of SSRS were negatively (Adjusted B=-0.273– -0.240, p<0.05) associated with specific CTQ scores. Conclusion Childhood trauma is still a common social and psychological problem. Individuals with childhood trauma show much more depression, anxiety, distorted cognition, personality deficits, and lower levels of social support, which may represent the social and psychological vulnerability for developing psychiatric disorders after childhood trauma experiences.

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