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252篇 您的检索式:作者名="Xiaodong Hu"
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1Mesenchymal stem cells: a new strategy for immunosuppression and tissue repair显示文摘间充质的干细胞(MSC ) 为治疗各种各样的疾病有大潜力,特别那些与织物有关损坏包含有免疫力的反应。各种各样的研究证明了 MSC 在 vitro 并且在 vivo 是强烈抑制免疫力的。我们的最近的研究证明了那未刺激的 MSC 确实不能免疫力的抑制;他们与 TNF- 伪, IL-1 伪或 IL-1 尾与激活的淋巴细胞的上层清液,或与 IFN- 纬的联合在刺激之上变得 potently 抑制免疫力。这观察表明在某些情形下面,煽动性的 cytokines 能实际上变得抑制免疫力。我们证明在调停 MSC 的免疫力的抑制的机制有一个种类变化:由告知 cytokine 的老鼠 MSC 的免疫力的抑制被氮的氧化物调停(没有) 而由告知 cytokine 的人的 MSC 的免疫力的抑制通过 indoleamine 被执行 2, 3-dioxygenase (伊多语) 。在有煽动性的 cytokines 的刺激之上,另外,老鼠和人的 MSC 分泌几白血球 chemokines 显然服务与 MSC 吸引有免疫力的房间进最近,在哪儿不或伊多语被预言很活跃。因此,由煽动性的刺激 cytokine 的 MSC 的免疫力的抑制经由 chemokines 的一致行动发生并且免疫者禁止没有或伊多语由 MSC 生产了。因此,我们的结果在对待有免疫力的回答导致的织物损害关于调停 MSC 的免疫力的抑制并且为 MSC 的更好的申请的机制提供新奇信息。Yufang Shi Gangzheng Hu Juanjuan Su Wenzhao Li Qing Chen Peishun Shou Chunliang Xu Xiaodong Chen Yin Huang Zhexin Zhu Xin Huang Xiaoyan Han Ningxia Xie Guangwen Ren 2010Cell Research2010,20,5:72
2Evaluation of a granulated formula for the nerve root type and vertebral artery type of cervical spondylosis:a multicenter,single-blind,randomized,controlled,phase Ⅲ clinical trial显示文摘OBJECTIVE:To evaluate the effectiveness and safety of cervical spondylosis formula granules in reducing the symptoms of patients with the nerve root type and the vertebral artery type of cervical spondylosis.METHODS:This was a multicenter, single-blind,randomized, controlled trial.From April 2002 to November 2003, 499 patients were randomly assigned to either the treatment or the control group.The treatment group was orally administered granules prepared with a formula for cervical spondylosis, while the control group was given Jingfukang granules.The treatment course was 1 month for both groups.RESULTS:In patients with the nerve root type of cervical spondylosis, the total effect rate in the treatment group(87.21%) was significantly higher than that in the control group(80.70%, P < 0.01).After the treatment period in both groups, the treatment group had a significantly greater rate of resolution of pain, numbness of the upper limbs, muscle strength of the upper limbs, and fatigue than the control group(all P < 0.05).In patients with the vertebral artery type of cervical spondylosis, the total effect rate in the treatment group(82.07%) was similar to that in the control group(71.21%, P >0.05).After the treatment period in both groups,the treatment group had a significantly greater rate of resolution of weakness of the waist and knees than the control group(P < 0.05).CONCLUSION:The cervical spondylosis formula granules significantly improve numbness, muscle strength, and fatigue, and reduce pain in patients with the nerve root type of cervical spondylosis,and improve the weakness of the waist and knees in patients with the vertebral artery type of cervical spondylosis.Luo Xiaodong Wang Peng Li Zhe Liang De Huang Feng Liu Jinwen Chen Xinyu Hu Guoheng Fang Suting Zhang Huajian 2017Journal of Traditional Chinese Medicine2017,37,2:28
3Prostate cancer identification: quantitative analysis of T2-weighted MR images based on a back propagation artificial neural network model显示文摘Computer-aided diagnosis(CAD) systems have been proposed to assist radiologists in making diagnostic decisions by providing helpful information. As one of the most important sequences in prostate magnetic resonance imaging(MRI), image features from T2-weighted images(T2WI) were extracted and evaluated for the diagnostic performances by using CAD. We extracted 12 quantitative image features from prostate T2-weighted MR images. The importance of each feature in cancer identification was compared in the peripheral zone(PZ) and central gland(CG), respectively. The performance of the computer-aided diagnosis system supported by an artificial neural network was tested. With computer-aided analysis of T2-weighted images, many characteristic features with different diagnostic capabilities can be extracted. We discovered most of the features(10/12) had significant difference(P<0.01) between PCa and non-PCa in the PZ, while only five features(sum average, minimum value, standard deviation, 10 th percentile, and entropy) had significant difference in CG. CAD prediction by features from T2 w images can reach high accuracy and specificity while maintaining acceptable sensitivity. The outcome is convictive and helpful in medical diagnosis.ZHAO Kai WANG ChengYan HU Juan YANG XueDong WANG He LI FeiYu ZHANG XiaoDong ZHANG Jue WANG XiaoYing 2015Science China(Life Sciences)2015,58,7:16
4COMPUTATIONAL FLUID DYNAMICS RESEARCH ON PRESSURE LOSS OF CROSS-FLOW PERFORATED MUFFLER显示文摘The pressure loss of cross-flow perforated muffler has been computed with the procedure of physical modeling,simulation and data processing. Three-dimensional computational fluid dynam-ics (CFD) has been used to investigate the relations of porosities,flow velocity and diameter of the holes with the pressure loss. Accordingly,some preliminary results have been obtained that pressure loss increases with porosity descent as nearly a hyperbolic trend,rising flow velocity of the input makes the pressure loss increasing with parabola trend,diameter of holes affects little about pressure loss of the muffler. Otherwise,the holes on the perforated pipes make the air flow gently and meanly,which decreases the air impact to the wall and pipes in the muffler. A practical perforated muffler is used to illustrate the available of this method for pressure loss computation,and the comparison shows that the computation results with the method of CFD has reference value for muffler design.HU Xiaodong ZHOU Yiqi FANG Jianhua MAN Xiliang ZHAO Zhengxu 2007Chinese Journal of Mechanical Engineering2007,20,2:14
5Laser performance of the SG-Ⅲ laser facility显示文摘SG-Ⅲ laser facility is now the largest laser driver for inertial confinement fusion research in China. The whole laser facility can deliver 180 kJ energy and 60 TW power ultraviolet laser onto target, with power balance better than 10%.We review the laser system and introduce the SG-Ⅲ laser performance here.Wanguo Zheng Xiaofeng Wei Qihua Zhu Feng Jing Dongxia Hu Jingqin Su Kuixing Zheng Xiaodong Yuan Hai Zhou Wanjun Dai Wei Zhou Fang Wang Dangpeng Xu Xudong Xie Bin Feng Zhitao Peng Liangfu Guo Yuanbin Chen Xiongjun Zhang Lanqin Liu Donghui Lin Zhao Dang Yong Xiang Xuewei Deng 2016High Power Laser Science and Engineering2016,4,3:13
6Laser performance upgrade for precise ICF experiment in SG-Ⅲ laser facility显示文摘The SG-Ⅲlaser facility(SG-Ⅲ)is the largest laser driver for inertial confinement fusion(ICF)researches in China,which has 48 beamlines and can deliver 180 kJ ultraviolet laser energy in 3 ns.In order to meet the requirements of precise physics experiments,some new functionalities need to be added to SG-Ⅲand some intrinsic laser performances need upgrade.So at the end of SG-Ⅲ's engineering construction,the 2-year laser performance upgrade project started.This paper will introduce the newly added functionalities and the latest laser performance of SG-Ⅲ.With these function extensions and performance upgrade,SG-Ⅲis now fully prepared for precise ICF experiments and solidly paves the way towards fusion ignition.Wanguo Zheng Xiaofeng Wei Qihua Zhu Feng Jing Dongxia Hu Xiaodong Yuan Wanjun Dai Wei Zhou Fang Wang Dangpeng Xu Xudong Xie Bin Feng Zhitao Peng Liangfu Guo Yuanbin Chen Xiongjun Zhang Lanqin Liu Donghui Lin Zhao Dang Yong Xiang Rui Zhang Fang Wang Huaiting Jia Xuewei Deng 2017Matter and Radiation at Extremes2017,2,5:13
7Quantitative analysis of diffusion-weighted magnetic resonance images:differentiation between prostate cancer and normal tissue based on a computer-aided diagnosis system显示文摘Diffusion-weighted imaging(DWI) is considered to be one of the dominant modalities used in prostate cancer(PCa) detection and the assessment of lesion aggressiveness,especially for peripheral zone(PZ) PCa.Computer-aided diagnosis(CAD),which is capable of automatically extracting and evaluating image features,can integrate multiple parameters and improve the detection of PCa.In this study,13 quantitative image features were extracted from DWI by CAD,and diagnostic efficacy was analyzed in both the PZ and transition zone(TZ).The results demonstrated that there was a significant difference(P<0.05) between PCa and non-PCa for nine of the 13 features in the PZ and five of the 13 features in the TZ.Besides,the prediction outcome of CAD had a strong correlation with the DWI scores that were graded by experienced radiologists according to the Prostate Imaging-Reporting and Data System Version 2(PI-RADS v2).Ge Gao Chengyan Wang Xiaodong Zhang Juan Hu Xuedong Yang He Wang Jue Zhang Xiaoying Wang 2017Science China(Life Sciences)2017,60,1:13
8H. pylori Escape Host Immunoreaction Through Inhibiting ILK Expression by VacA显示文摘Helicobacter pylori (H。pylori ) 尽管有精力旺盛的有免疫力的回答,固执地开拓殖民地于胃的 mucosa。Vacuolating 细胞毒素由 H 藏匿了。pylori 结果是有势力 immunomodulatory 毒素,而是包含的信号 transduction 小径没在巨噬细胞被学习。我们在这研究观察了那 vacA 缺乏的 H。pylori 导致了连接 integrin 的 kinase (同类) 和 endothelial 的显著地更高的表示氮的氧 synthase (eNOS ) ,并且显著地在 monocyte/macrophage-like U937 房间的反应的氧种类(ROS ) 的更多的生产,同样与 isogenic vacA+H 相比。pylori。在 U937 房间 overexpressing 同类的 eNOS mRNA 的表示显著地与空向量与那些 transfected 相比被增加。因此, vacA 缺乏的 H。pylori 出现到 upregulate 同类表示,调制 eNOS 并且作为结果的表示,刺激 ROS 的生产。,帮助 H 是 VacA 由禁止同类表示阻止如此的进程。pylori 逃跑主人免疫反应。这机制解释,至少部分地, H 的坚持的感染。在胃的 pylori。Jianping Yuan Ping Li Jing Tao Xiaodong Shi Baoyu Hu Huabiao Chen Xiaokui Guo 2009Cellular & Molecular Immunology2009,6,3:12
9Expression of VEGFR2 and NRP-1 in non-small cell lung cancer and their clinical significance显示文摘Objective: Vascular-targeted therapy is gradually becoming more appealing for patients with lung cancer. It is unclear whether vascular endothelial growth factor receptor 2(VEGFR2) and neuropilin-1(NRP-1) can be biomarkers for clinical treatment. We aimed to investigate the expression levels of VEGFR2 and NRP-1 in human non-small cell lung cancer(NSCLC) and their clinical significance by observing patient prognosis. Methods: VEGFR2 and NRP-1 were assessed by immunohistochemistry(IHC) in 40 patients with NSCLC and in 10 patients with benign lesions of lung; kinase insert domain receptor(KDR) and NRP-1 copy number gain(CNG) was assessed by fluorescence in situ hybridization(FISH). The distributions of overall survival(OS) and progression-free survival(PFS) were estimated using the Kaplan-Meier method and compared between groups by log-rank test.Results: Rates of positive immunostaining for VEGFR2 and NRP-1 were 58% and 55%, respectively. KDR and NRP-1 CNG(+) were detected in 32.5% and 30% of tumors, respectively. Levels of both VEGFR2 and NRP-1 in lung tumors were significantly different than in the control tissue(χ2=11.22, P=0.001; χ2=9.82, P=0.001, respectively); similar results were obtained using CNGs(χ2=4.39, P=0.036; χ2=3.95, P=0.046, respectively). Statistically significant correlations were observed with histological grade, clinical TNM stage and the lymph node status(P<0.05), but not age, gender or pathology type(P>0.05). VEGFR2 showed a strong correlation with NRP-1(Rs=0.68, P=0.00); similar results were observed with KDR and NRP-1 CNG(Rs=0.32, P=0.04). Significant differences in OS and PFS were observed between the groups with higher VEGFR2 and NRP-1 and those with lower expression(P<0.05). Conclusions: According to these data, VEGFR2 and NRP-1 are highly expressed in NSCLC. We can conclude that they play a key role in NSCLC occurrence, development and metastasis and are associated with patient prognosis(P<0.05 for OS and PFS). This information will be beneficial for clinical antiangiogenic treatment in NSCLC.Manhua Ding Liang Liu Chengxi Hu Yi Liu Yun Qiao Xiaodong Jiang 2014Chinese Journal of Cancer Research2014,26,6:11
10Effects of tacrolimus and cyclosporine treatment on metabolic syndrome and cardiovascular risk factors after renal transplantation:a meta-analysis显示文摘Xue Wenrui Zhang Qiang Xu Yue Wang Wei Zhang Xiaodong Hu Xiaopeng 2014Chinese Medical Journal2014,,12:10
11A Brief Introduction to BNU-HESM1.0 and Its Earth Surface Temperature Simulations显示文摘Integrated assessment models and coupled earth system models both have their limitations in understanding the interactions between human activity and the physical earth system. In this paper,a new human–earth system model,BNUHESM1.0,constructed by combining the economic and climate damage components of the Dynamic Integrated Model of Climate Change and Economy to the BNU-ESM model,is introduced. The ability of BNU-HESM1.0 in simulating the global CO2 concentration and surface temperature is also evaluated. We find that,compared to observation,BNU-HESM1.0underestimates the global CO2 concentration and its rising trend during 1965–2005,due to the uncertainty in the economic components. However,the surface temperature simulated by BNU-HESM1.0 is much closer to observation,resulting from the overestimates of surface temperature by the original BNU-ESM model. The uncertainty of BNU-ESM falls within the range of present earth system uncertainty,so it is the economic and climate damage component of BNU-HESM1.0 that needs to be improved through further study. However,the main purpose of this paper is to introduce a new approach to investigate the complex relationship between human activity and the earth system. It is hoped that it will inspire further ideas that prove valuable in guiding human activities appropriate for a sustainable future climate.YANG Shili DONG Wenjie CHOU Jieming FENG Jinming YAN Xiaodong WEI Zhigang YUAN Wenping GUO Yan TANG Yanli HU Jiacong 2015Advances in Atmospheric Sciences2015,32,12:8
12An infrared target intrusion detection method based on feature fusion and enhancement显示文摘Infrared target intrusion detection has significant applications in the fields of military defence and intelligent warning.In view of the characteristics of intrusion targets as well as inspection difficulties,an infrared target intrusion detection algorithm based on feature fusion and enhancement was proposed.This algorithm combines static target mode analysis and dynamic multi-frame correlation detection to extract infrared target features at different levels.Among them,LBP texture analysis can be used to effectively identify the posterior feature patterns which have been contained in the target library,while motion frame difference method can detect the moving regions of the image,improve the integrity of target regions such as camouflage,sheltering and deformation.In order to integrate the advantages of the two methods,the enhanced convolutional neural network was designed and the feature images obtained by the two methods were fused and enhanced.The enhancement module of the network strengthened and screened the targets,and realized the background suppression of infrared images.Based on the experiments,the effect of the proposed method and the comparison method on the background suppression and detection performance was evaluated,and the results showed that the SCRG and BSF values of the method in this paper had a better performance in multiple data sets,and it’s detection performance was far better than the comparison algorithm.The experiment results indicated that,compared with traditional infrared target detection methods,the proposed method could detect the infrared invasion target more accurately,and suppress the background noise more effectively.Xiaodong Hu Xinqing Wang Xin Yang Dong Wang Peng Zhang Yi Xiao 2020Defence Technology(防务技术)2020,16,3:8
13Reproductive toxicity of organic extracts from petrochemical plant effluents discharged to the Yangtze River,China显示文摘Water pollution of the Yangtze River in China became one of challenges that the government is facing today.Increasing numbers of petrochemical plants were built along the river in past decades,and numbers of organic chemicals were discharged into the river.Our goal was to establish in vitro system on rat sertoli cells,spermatogenic cells and leydig cells to investigate the reproductive toxicity potential induced by organic extracts from petrochemical effluents.Our results showed that the organic extract depressed the viability(p<0.01) and destroyed the plasma membrane integrity of sertoli cells and spermatogenic cells to a certain degree.Accordingly,proportion of early apoptotic sertoli cells and late apoptotic spermatogenic cells increased significantly.Although significant morphological changes were not detected for leydig cells,the extract was observed to inhibit their testosterone production(p<0.01).Sertoli cells and spermatogenic cells appeared to be more sensitive and maybe the main targets of the key toxins.These results suggested that the in vitro system on rat testicular cells may be useful to predicate reproductive toxicity potential of organic extracts from petrochemical effluents.More attention should be paid to the petrochemical effluents,because long-term accumulation of these organic compounds in organisms may cause spermatogenesis malfunction and testosterone reduction.Xiaoyi Wang Wei Shi Jiang Wu Yingqun Hao Guanjiu Hu Hongling Liu Xiaodong Han Hongxia Yu 2010Journal of Environmental Sciences2010,22,2:7
14Mechanism of the interaction between Au nano-particles and polymerase in nanoparticle PCR显示文摘Nanoparticle PCR is a novel method to optimize DNA amplification. It performs well in improving specificity, enhancing sensitivity and speed. Several mechanisms were proposed in previous studies: one was based on the interaction between gold nanoparticles (AuNPs) and DNA while the other was attributed to the heat transfer property of AuNPs. In this paper, we propose that the interaction between AuNPs and DNA polymerase can significantly influence PCR. First, the addition of DNA polymerase can eliminate the inhibitory effects of excess AuNPs. Second, the addition of AuNPs will increase yield of the desired PCR product and make the optimum concentration of DNA polymerase move to higher value. Third, while excess polymerase might inhibit amplification efficiency, AuNPs can reverse this process and the yield of PCR amplification. Based on these results we propose a possible mechanism that AuNPs might modulate the activity of polymerase and improve PCR amplification.MI LiJuan ZHU HongPing ZHANG XiaoDong HU Jun FAN ChunHai 2007Chinese Science Bulletin2007,52,17:7
15Modeling permafrost properties in the Qinghai-Xizang(Tibet) Plateau显示文摘Water and heat dynamics in the active layer at a monitoring site in the Tanggula Mountains, located in the permafrost region of the Qinghai-Xizang(Tibet) Plateau(QXP), were studied using the physical-process-based COUPMODEL model, including the interaction between soil temperature and moisture under freeze-thaw cycles. Meteorological, ground temperature and moisture data from different depths within the active layer were used to calibrate and validate the model. The results indicate that the calibrated model satisfactorily simulates the soil temperatures from the top to the bottom of the soil layers as well as the moisture content of the active layer in permafrost regions. The simulated soil heat flux at depths of 0 to 20 cm was consistent with the monitoring data, and the simulations of the radiation balance components were reasonable. Energy consumed for phase change was estimated from the simulated ice content during the freeze/thaw processes from 2007 to 2008. Using this model, the active layer thickness and the energy consumed for phase change were predicted for future climate warming scenarios. The model predicts an increase of the active layer thickness from the current 330 cm to approximately 350–390 cm as a result of a 1–2°C warming. However, the effect active layer thickness of more precipitation is limited when the precipitation is increased by 20%–50%. The COUPMODEL provides a useful tool for predicting and understanding the fate of permafrost in the QXP under a warming climate.HU GuoJie ZHAO Lin WU XiaoDong LI Ren WU TongHua XIE ChangWei PANG QiangQiang XIAO Yao LI WangPing QIAO YongPing SHI JianZong 2015Science China Earth Sciences2015,58,12:7
16Microstructure and strengthening mechanism of hot-extruded ultralight Mg-Li-Al-Sn alloys with high strength显示文摘Duplex-structured Mg-7Li-2Al-1.5Sn alloys with high strength were fabricated and their strengthening mechanism was investigated.The Mg-7Li-2Al-1.5Sn alloys were prepared by casting and extruded at the temperature of 533 K with an extrusion ratio of 25:1.The microstructure and mechanical properties of Mg-7Li-2Al-1.5Sn alloys were systematically investigated by OM,XRD,SEM,TEM,and tensile tests.The results show that Mg-7Li-2Al-1.5Sn alloys are mainly composed ofα-Mg,β-Li,LiMgAl_(2),Mg_(2)Sn and Li_(2)MgSn phases.The yield strength(YS),ultimate tensile strength(UTS)and elongation(EL)of the extruded alloy at room temperature reach 250 MPa,324 MPa and 11.9%,respectively.A lot of Sn-rich precipitates(Mg_(2)Sn and Li_(2)MgSn)are precipitated during extrusion with an average size of∼14 nm,which is beneficial to the grain refinement.Dynamic recrystallization occurs during hot deformation and the nanoprecipitates effectively refine the dynamic recrystallized(DRXed)grains.Besides,the residual dislocations existed in DRXed and un-DRXed grains result in the dislocation strengthening in the extruded alloy.Mg7Li-2Al-1.5Sn alloys possess excellent high-temperature mechanical properties with the YS,UTS and EL of 200 MPa,237 MPa and 26.7%at 423 K,respectively.Sn-rich precipitates with good thermal stability can effectively prevent grain growth,which is good for the improvement of the high-temperature performance of Mg-Li-Al-Sn alloy.Gang Zhou Yan Yang Hanzhu Zhang Faping Hu Xueping Zhang Chen Wen Weidong Xie Bin Jiang Xiaodong Peng Fusheng Pan 2022Journal of Materials Science & Technology2022,,8:7
17Study on Airflow Characteristics in the Semi-Closed Irregular Narrow Flow channel显示文摘The air-jet loom is widely used in the textile industry. The interaction mechanism of airflow and yarn is not clear in such a narrow flow channel, the gas consumption is relatively large, the yarn motion is unstable and the weft insertion is often interrupted during the operation. In order to study the characteristics of the semi-closed flow field in profiled dents, the momentum conservation equation is modified and the model parameters and boundary conditions are set. Compared with the different r, the ratio of profiled dent's thickness and gap, the results show that the smaller the r is, the smaller the velocity fluctuations of the airflow is. When the angle of profiled dents ? is close to zero, the diffusion of the airflow will be less. The experiment is also conducted to verify the result of the simulation with a high-speed camera and pressure sensor in profiled dents. The airflow characteristics in the semi-closed irregular narrow flow channel in the paper would provide the theoretical basis for optimizing the weft insertion process of the air-jet loom.JIN Yuzhen HU Xiaodong ZHU Linhang HU Xudong JIN Yingzi 2016Journal of Thermal Science2016,25,2:6
18Genetic control of flowering time in woody plants: Roses as an emerging model显示文摘Genetic control of the timing of flowering in woody plants is complex and has yet to be adequately investigated due to their long life-cycle and difficulties in genetic modification.Studies in Populus,one of the best woody plant models,have revealed a highly conserved genetic network for flowering timing in annuals.However,traits like continuous flowering cannot be addressed with Populus.Roses and strawberries have relatively small,diploid genomes and feature enormous natural variation.With the development of new genetic populations and genomic tools,roses and strawberries have become good models for studying the molecular mechanisms underpinning the regulation of flowering in woody plants.Here,we review findings on the molecular and genetic factors controlling continuous flowering in roses and woodland strawberries.Natural variation at TFL1 orthologous genes in both roses and strawberries seems be the key plausible factor that regulates continuous flowering.However,recent efforts suggest that a two-recessive-loci model may explain the controlling of continuous flowering in roses.We propose that epigenetic factors,including non-coding RNAs or chromatin-related factors,might also play a role.Insights into the genetic control of flowering time variation in roses should benefit the development of new germplasm for woody crops and shed light on the molecular genetic bases for the production and maintenance of plant biodiversity.Xue Dong Xiaodong Jiang Guoqiang Kuang Qingbo Wang Micai Zhong Dongmin Jin Jinyong Hu 2017Plant Diversity2017,39,2:6
19The O and H isotope characteristics of water from major rivers in China显示文摘Isotopic compositions of the water sources and evapotranspiration in large rivers of China are not well explored. In this investigation, d18 O and dD values of water from major large rivers of China are integrated to understand the spatial and temporal variations in the isotopes of water and d-excess. River water samples were collected from the channels and tributaries of the Changjiang, Yellow, Songhua and Liao Rivers in China. Water from upstream was generally enriched with light isotopes relative to that from downstream areas. Water from the Songhua River and upper reach of the Changjiang River has relatively negative isotopic values impacted by latitude and altitude effects, respectively. The spatial pattern showed that d18O-H2 O values in rivers mainly ranged from-9 to-7 % in most of China based on roughly mapped contours, and rivers enriched in light isotopes were primarily located in the Tibetan Plateau and northeast China The slopes of linear regression from the Yellow and Liao Rivers suggested that the loss of water by direct evaporation shifted the isotopes of water, especially in some small tributaries. Additionally, there was a narrow range of low d18OH2 O values from the main channel of rivers during the lowflow season relative to the high-flow season due to influence of the monsoon climate. No distinct spatial variation of d-excess values was found in the rivers of China. However, water samples in some rivers with low d-excess values had high d18 O values, indicating that evaporation in the tributaries has led to significant water loss, especially in tributaries of the Yellow and Liao Rivers.Si-Liang Li Fu-Jun Yue Cong-Qiang Liu Hu Ding Zhi-Qi Zhao Xiaodong Li 2015Chinese Journal Of Geochemistry2015,34,1:5
20Modeling Hydrothermal Transfer Processes in Permafrost Regions of Qinghai-Tibet Plateau in China显示文摘Hydrothermal processes are key components in permafrost dynamics; these processes are integral to global warming. In this study the coupled heat and mass transfer model for(Coup Model) the soil-plant-atmosphere-system is applied in high-altitude permafrost regions and to model hydrothermal transfer processes in freeze-thaw cycles. Measured meteorological forcing and soil and vegetation properties are used in the Coup Model for the period from January 1, 2009 to December 31, 2012 at the Tanggula observation site in the Qinghai-Tibet Plateau. A 24-h time step is used in the model simulation. The results show that the simulated soil temperature and water content, as well as the frozen depth compare well with the measured data. The coefficient of determination(R2) is 0.97 for the mean soil temperature and 0.73 for the mean soil water content, respectively. The simulated soil heat flux at a depth of 0–20 cm is also consistent with the monitored data. An analysis is performed on the simulated hydrothermal transfer processes from the deep soil layer to the upper one during the freezing and thawing period. At the beginning of the freezing period, the water in the deep soil layer moves upward to the freezing front and releases heat during the freezing process. When the soil layer is completely frozen, there are no vertical water exchanges between the soil layers, and the heat exchange process is controlled by the vertical soil temperature gradient. During the thawing period, the downward heat process becomes more active due to increased incoming shortwave radiation at the ground surface. The melt water is quickly dissolved in the soil, and the soil water movement only changes in the shallow soil layer. Subsequently, the model was used to provide an evaluation of the potential response of the active layer to different scenarios of initial water content and climate warming at the Tanggula site. The results reveal that the soil water content and the organic layer provide protection against active layer deepening in summer, so climate warming will cause the permafrost active layer to become deeper and permafrost degradation.HU Guojie ZHAO Lin LI Ren WU Tonghua WU Xiaodong PANG Qiangqiang XIAO Yao QIAO Yongping SHI Jianzong 2015Chinese Geographical Science2015,25,6:4
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