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90篇 您的检索式:作者名="Xiaodong Ren"
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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
2From concept to reality-A review to the primary test stand and its preliminary application in high energy density physics显示文摘Pulsed power technology,whereas the electrical energy stored in a relative long period is released in much shorter timescale,is an efficient method to create high energy density physics(HEDP)conditions in laboratory.Around the beginning of this century,China Academy of Engineering Physics(CAEP)began to build some experimental facilities for HEDP investigations,among which the Primary Test Stand(PTS),a multi-module pulsed power facility with a nominal current of 10 MA and a current rising time~90 ns,is an important achievement on the roadmap of the electro-magnetically driven inertial confinement fusion(ICF)researches.PTS is the first pulsed power facility beyond 10 TW in China.Therefore,all the technologies have to be demonstrated,and all the engineering issues have to be overcome.In this article,the research outline,key technologies and the preliminary HEDP experiments are reviewed.Prospects on HEDP research on PTS and pulsed power development for the next step are also discussed.Jianjun Deng Weiping Xie Shuping Feng Meng Wang Hongtao Li Shengyi Song Minghe Xia Ji Ce An He Qing Tian Yuanchao Gu Yongchao Guan Bin Wei Xianbin Huang Xiaodong Ren Jiakun Dan Jing Li Shaotong Zhou Hongchun Cai Siqun Zhang Kunlun Wang Qiang Xu Yujuan Wang Zhaohui Zhang Guilin Wang Shuai Guo Yi He Yiwei Zhou Zhanji Zhang Libing Yang Wenkang Zou 2016Matter and Radiation at Extremes2016,1,1:19
3Characteristics of dissolved organic matter in lakes with different eutrophic levels in southeastern Hubei Province,China显示文摘Dissolved organic matter(DOM)plays a crucial role in both the carbon cycle and geochemical cycles of other nutrient elements,which is of importance to the management and protection of the aquatic environments.To achieve a more comprehensive understanding the characteristics of DOM in the Changjiang(Yangtze)River basin,water samples from four natural lakes(Xiandao,Baoan,Daye,and Qingshan)in southeastern Hubei Province in China with different eutrophication levels were collected and analyzed.The optical characteristics were analyzed using ultraviolet-visible spectrophotometry and excitation-emission matrix spectroscopy coupled with parallel factor analysis.The results show that:(1)two humic-like components(C1 and C2)and two protein-like substances(C3 and C4)of DOM were identified in all waterbodies;(2)C3 originated primarily from the degradation of microalgae and contributed substantially to humic-like components during transformation.C4 was widely present in the Changjiang River basin and its formation was related to microbial activity,rather than algal blooms or seasons.Influenced by the water mixing,the protein-like components were more likely to be transformed by microorganism,whereas humic-like components were more easily to be photobleached;(3)the concentration of DOM and the fluorescence intensity of humic-like components gradually increased with rising lake eutrophication levels.With respect to protein-like components,only C3 showed changes along the eutrophication gradients;(4)DOM showed a high affinity with permanganate index(COD Mn)and chlorophyll a(chl a)while the relationship was variable with phosphorus.This study helps us systematically understand the DOM characteristics,microbial activities,and pollutant transformation in the Changjiang River basin and provides reference to the ecological restoration of aquatic environments.Weixiang REN Xiaodong WU Xuguang GE Guiying LIN Mengdie ZHOU Zijie LONG Xinhui YU Wei TIAN 2021Journal of Oceanology and Limnology2021,39,4:8
4Mechanistic understanding of the role separators playing in advanced lithium-sulfur batteries显示文摘The lithium-sulfur battery is considered one of the most promising candidates for portable energy storage devices due to its low cost and high energy density.However,many critical issues,including polysulfide shuttling,self-discharge,lithium dendritic growth,and thermal hazards need to be addressed before the commercialization of lithium-sulfur batteries.To this end,tremendous efforts have been made to explore battery configurations and components,such as electrodes,electrolytes,and separators,among which the separator plays an especially critical role in addressing aforementioned issues.Thus,this review analyzes the mechanisms and interactions of these critical issues and summarizes both the function of separators and recent progress made towards remedying such issues.Additionally,promising directions for the development of separators in lithium-sulfur batteries are proposed.Zhaohuan Wei Yaqi Ren Joshua Sokolowski Xiaodong Zhu Gang Wu 2020InfoMat2020,2,3:8
5MIKC^(C)-type MADS-box genes in Rosa chinensis: the remarkable expansion of ABCDE model genes and their roles in floral organogenesis显示文摘MIKC^(C)-type MADS-box(MIKC^(C))genes encode transcription factors that have crucial roles in controlling floral organogenesis and flowering time in plants.Although this gene family has been well characterized in many plant species,its evolutionary and comprehensive functional analysis in rose is lacking.In this study,58 non-redundant MIKC^(C)uni-transcripts were extensively identified from rose transcriptomes.Phylogenetic analysis placed these genes into 12 clades with their Arabidopsis and strawberry counterparts,and revealed that ABCDE model(including AP1/FUL,AP3/PI,AG,and SEP clades),and SOC1 and AGL6 clade genes have remarkably expanded in Rosa chinensis,whereas genes from the FLC and AGL17 clades were undetectable.Sequence alignments suggest that the AP3/PI clade may contribute to more specific functions in rose due to a high variation of amino acid residues within its MADS-box domains.A comparative analysis of gene expression in specific floral organ differentiation stages and floral organs between R.chinensis cv.Old Blush and the closely related mutant genotype R.chinensis cv.Viridiflora(floral organs mutated into leaf-like structures)further revealed the roles of ABCDE model genes during floral organogenesis in rose.Analysis of co-expression networks provided an overview of the regulatory mechanisms of rose MIKC^(C)genes and shed light on both the prominent roles of AP3/PI clade genes in floral organogenesis and the roles of RcAGL19,RcAGL24,and RcSOC1 in regulating floral transition in rose.Our analyses provide an overall insight of MIKC^(C)genes in rose and their potential roles in floral organogenesis.Jinyi Liu Xiaodong Fu Yuwei Dong Jun Lu Min Ren Ningning Zhou Changquan Wang 2018Horticulture Research2018,5,1:7
6Changes in the gut microbiota mediate the differential regulatory effects of two glucose oxidases produced by Aspergillus niger and Penicillium amagasakiense on the meat quality and growth performance of broilers显示文摘Background: Glucose oxidase(GOD), an aerobic dehydrogenase, has been used as an antibiotic substitute in feed.A study was conducted to evaluate the differential effects of 2 different GODs fermented by Aspergillus niger or Penicillium amagasakiense on caecal microbiota and to further illuminate the potential roles of changes in the gut microbiota in regulating the growth performance and meat quality of broiler chickens.Results: A total of 420 one-day-old healthy Arbor Acres broilers were randomly assigned to 4 treatments: the control group,the antibiotic growth promoter(AGP) supplementation group, and the GOD-A and GOD-P(GODs produced by A. niger and P. amagasakiense, respectively) groups. As a result, supplementation with GOD produced by P. amagasakiense could significantly improve the average daily weight gain and average daily feed intake of broilers before 21 days of age by significantly increasing the enzymatic activities of jejunal amylase and those of ileal amylase, chymotrypsin, and lipase in21-day-old broilers and could increase the enzymatic activities of duodenal amylase, jejunal amylase and lipase, and ileal chymotrypsin and lipase in 42-day-old broilers. Meanwhile, compared with AGP treatment, supplementation with GOD produced by P. amagasakiense significantly decreased the L value of 21-day-old broilers and the Δp H and L* value of 42-day-old broilers, while supplementation with GOD produced by A. niger significantly increased the p H24 hvalue of 21-day-old and 42-day-old broilers by reducing plasma malondialdehyde content. By using 16 S r RNA sequencing, we found that the beneficial bacteria and microbiota in broilers were not disturbed but were improved by GOD supplementation compared with ADP treatment, including the genera Eubacterium and Christensenel a and the species uncultured_Eubacterium_sp,Clostridium_asparagiforme, and uncultured_Christensenel a_sp, which were positively related to the improved intestinal digestive enzymatic activities, growth performance, and meat quality of broilers.Conclusion: The altered gut microbiota induced by supplementation with glucose oxidase produced by P. amagasakiense mediate better regulatory effects on the meat quality and growth performance of broilers than that induced by supplementation with glucose oxidase produced by A. niger.Shengru Wu Xiaodong Chen Taohuan Li Hao Ren Lixin Zheng Xiaojun Yang 2020Journal of Animal Science and Biotechnology2020,11,4:7
7Modeling 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
8Constitutive Modeling and Hot Deformation Behavior of Duplex Structured Mg–Li–Al–Sr Alloy显示文摘Hot deformation behavior of an as-extruded duplex structured Mg–9Li–3Al–2.5Sr alloy is investigated via hot compression tests conducted at 200–350 °C with strain rate of 0.001–1 s-1.The flow behavior of Mg–9Li–3Al–2.5Sr alloy can be described accurately by hyperbolic sine constitutive equation and the average activation energy for deformation is calculated as 143.5 k J/mol.Based on a dynamic materials model,the processing maps of Mg–9Li–3Al–2.5Sr alloy which describe the variation of power dissipation efficiency are constructed as a function of temperature and strain rate.The processing maps exhibit an area of discontinuous dynamic recrystallization occurring at 280–300 °C with strain rate of 0.001–0.01 s-1,which corresponds to the optimum hot working conditions.Yan hang Xiaodong Peng Fengjuan Ren Haiming Wen Junfei Su Weidong xie 2016Journal of Materials Science & Technology2016,32,12:6
9Novel synthesis of N-doped graphene as an efficient electrocatalyst towards oxygen reduction显示文摘做氮的 graphene (NG ) 被一个新奇、灵巧、可伸缩的自底向上的方法成功地综合。退火的 NG (NG -- 一) 拥有的高特定的表面区域和一块层次多孔的质地,和在在碱、酸的媒介的氧减小反应的展出显著地改进的 electrocatalytic 活动。分子的动态模拟显示了的 Ab initio 那快速的 H 转移和六成员的 N 结构的热力学的稳定性在 600 敮 x 从 pyrrolic 把包含 N 种类的转变提升了到Ruguanq Ma Xiaodong Ren Bao Yu Xia Yao Zhou Chi Sun Qian Liu Jianjun Liu Jiacheng Wang 2016Nano Research2016,9,3:6
10Ambient noise surface wave tomography of marginal seas in east Asia显示文摘We conducted ambient noise tomography in east Asia, including the Chinese coastal provinces, Korea Peninsular, Japan,Taiwan Island, and marginal seas in between. We retrieved Rayleigh Green's functions from inter-station correlations of 12 months of continuous waveform data at 573 broadband stations in the region. We obtained group and phase velocity dispersion curves and dispersion maps for periods from 10 to 70 s and inverted for 3D Vs model of the crust and uppermost mantle. Moho and lithosphere thickness were derived from the 3D model. We observed three prominent low velocity zones in the upper mantle, two in the accretionary wedges above the Pacific and Philippine subduction slabs and one beneath the Changbai Mountain region. The crust and lithosphere are generally thin in the region. The velocity anomalies, crustal thickness, and lithosphere thickness all show a similar trend in NNE-SSW direction. The lithosphere shows a striking ' sausage'-type structure with alternating thickness. The crust thickness and lithosphere thickness both decrease progressively from NW to SE direction, which coincides with the distribution of episodic magmatism in SE China.We propose that the subduction of paleo-Pacific slab and its rollback were mainly responsible for the crustal and lithosphere extension and the mantle lithosphere removal in east Asia.Qing Wang XiaoDong Song JianYe Ren 2017Earth and Planetary Physics2017,1,1:6
11Effect of substrate cooling on the epitaxial growth of Ni-based single-crystal superalloy fabricated by direct energy deposition显示文摘The columnar-to-equiaxed transition(CET)or the formation of stray grains in the laser melting deposition is the least desirable for the repair of single-crystal blades.In this work,the forced water-cooling was conducted on a single-crystal Rene N5 substrate during the direct energy deposition(DED).The single track remelting,one-layer,two-layer,and eight-layer depositions were investigated to explore the grain growth mechanism.The solidification conditions of the DED process,including temperature field,temperature gradient,and solidification speed,were numerically analyzed by a finite element model.The single-track remelting results showed that the fraction of columnar crystal regions increases from55.81%in the air-cooled sample to 77.14%in the water-cooled one.The single-track deposits of one-and two-layer have the same trend,where the proportion of columnar crystal height was higher under the forced water-cooled condition.The electron backscattered diffraction(EBSD)grain-structure maps of an eight-layer deposit show that the epitaxial growth height increases from 1 mm in the air-cooling sample to 1.5 mm in the water-cooling one.The numerical results showed that the tempe rature gradient in[0011 direction was significantly increased by using forced water-cooling.In conclusion,the in-situ substrate cooling can become a potential method to promote epitaxial growth during DED via the influence on CET occurrence.Jianwen Nie Chaoyue Chen Longtao Liu Xiaodong Wang Ruixin Zhao Sansan Shuai Jiang Wang Zhongming Ren 2021Journal of Materials Science & Technology2021,,3:6
12Fe5C2 nanoparticles as low-cost HER electrocatalyst:the importance of Co substitution显示文摘Constructing and understanding the doping effect of secondary metal in transition metal carbide(TMC)catalysts is pivotal for the design of low-cost hydrogen evolution reaction(HER) electrocatalysts. In this work, we developed a wet-chemistry strategy for synthesizing Co-modified Fe_5C_2 nanoparticles((Fe_(1-x)Cox)_5C_2 NPs) as highly active HER electrocatalysts in basic solution. The structure of(Fe_(1-x)Cox)_5C_2 NPs was characterized by X-ray diffraction(XRD), extended X-ray absorption fine structure spectra(EXAFS) and scanning/transmission electron microscopy(S/TEM), indicating that the isomorphous substitution of cobalt in the lattice of Fe_5C_2.(Fe_(0.75) Co_(0.25))_5C_2 exhibited the best HER activity(174 mV for j = -10 mA/cm^2). Computational calculation results indicate that Co provides the most active site for HER. X-ray adsorption spectra(XAS) studies further suggested that the electron transfer in Fe–C bonds are enhanced by the substitution of Co, which modulates the hydrogen adsorption on the adjacent electronic-enriched carbon, and therefore promotes HER activity. Our results affirm the design of lowcost bimetallic TMCs based HER catalysts.Siwei Li Pengju Ren Ce Yang Xi Liu Zhen Yin Weizhen Li Hanjun Yang Jian Li Xiaoping Wang Yi Wang Ruochen Cao Lili Lin Siyu Yao Xiaodong Wen Ding Ma 2018Science Bulletin2018,63,20:6
13Disentangling the factors that contribute to variation in forest biomass increments in the mid-subtropical forests of China显示文摘Mid-subtropical forests are the main vegetation type of global terrestrial biomes, and are critical for maintaining the global carbon balance. However, estimates of forest biomass increment in mid-subtropical forests remain highly uncertain. It is critically important to determine the relative importance of different biotic and abiotic factors between plants and soil, particularly with respect to their influence on plant regrowth. Consequently,it is necessary to quantitatively characterize the dynamicspatiotemporal distribution of forest carbon sinks at a regional scale. This study used a large, long-term dataset in a boosted regression tree(BRT) model to determine the major components that quantitatively control forest biomass increments in a mid-subtropical forested region(Wuyishan National Nature Reserve, China). Long-term,stand-level data were used to derive the forest biomass increment, with the BRT model being applied to quantify the relative contributions of various biotic and abiotic variables to forest biomass increment. Our data show that total biomass(t) increased from 4.62 9 106 to 5.30 9 106 t between 1988 and 2010, and that the mean biomass increased from 80.19 ± 0.39 t ha-1(mean ± standard error) to 94.33 ± 0.41 t ha-1in the study region. The major factors that controlled biomass(in decreasing order of importance) were the stand, topography, and soil. Stand density was initially the most important stand factor, while elevation was the most important topographic factor. Soil factors were important for forest biomass increment but have a much weaker influence compared to the other two controlling factors. These results provide baseline information about the practical utility of spatial interpolationmethods for mapping forest biomass increments at regional scales.Yin Ren Shanshan Chen Xiaohua Wei Weimin Xi Yunjian Luo Xiaodong Song Shudi Zuo Yusheng Yang 2016Journal of Forestry Research2016,27,4:5
14120 mm Single-crystalline perovskite and wafers: towards viable applications显示文摘As the large single-crystalline silicon wafers have revolutionized many industries including electronics and solar cells, it is envisioned that the availability of large single-crystalline perovskite crystals and wafers will revolutionize its broad applications in photovoltaics, optoelectronics, lasers, photodetectors, light emitting diodes(LEDs), etc. Here we report a method to grow large single-crystalline perovskites including single-halide crystals: CH3NH3PbX3(X=I, Br, Cl), and dual-halide ones:CH3NH3Pb(ClxBr1.x)3 and CH3NH3Pb(BrxI1.x)3, with the largest crystal being 120 mm in length. Meanwhile, we have advanced a process to slice the large perovskite crystals into thin wafers. It is found that the wafers exhibit remarkable features:(1)its trap-state density is a million times smaller than that in the microcrystalline perovskite thin films(MPTF);(2) its carrier mobility is 410 times higher than its most popular organic counterpart P3HT;(3) its optical absorption is expanded to as high as910 nm comparing to 797 nm for the MPTF;(4) while MPTF decomposes at 150 °C, the wafer is stable at high temperature up to270 °C;(5) when exposed to high humidity(75% RH), MPTF decomposes in 5 h while the wafer shows no change for overnight;(6) its photocurrent response is 250 times higher than its MPTF counterpart. A few electronic devices have been fabricated using the crystalline wafers. Among them, the Hall test gives low carrier concentration with high mobility. The trap-state density is measured much lower than common semiconductors. Moreover, the large SC-wafer is found particularly useful for mass production of integrated circuits. By adjusting the halide composition, both the optical absorption and the light emission can be fine-tuned across the entire visible spectrum from 400 nm to 800 nm. It is envisioned that a range of visible lasers and LEDs may be developed using the dual-halide perovskites. With fewer trap states, high mobility, broader absorption, and humidity resistance, it is expected that solar cells with high stable efficiency maybe attainable using the crystalline wafers.Yucheng Liu Xiaodong Ren Jing Zhang Zhou Yang Dong Yang Fengyang Yu Jiankun Sun Changming Zhao Zhun Yao Bo Wang Qingbo Wei Fengwei Xiao Haibo Fan Hao Deng Liangping Deng Shengzhong (Frank) Liu 2017Science China Chemistry2017,60,10:5
15Modeling 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
16Effect of Ammonia on the Performance of Catalysts for Selective Hydrogenation of 1-Methylnaphthalene显示文摘The effect of ammonia on the catalytic performance for 1-methylnaphthalene(1-MN) selective hydrogenation saturation was studied with Co-Mo/γ-Al_2O_3, Ni-W/γ-Al_2O_3, Ni-Mo/γ-Al_2O_3, and Ni-Mo-W/γ-Al_2O_3 catalysts. The results indicated that Ni-Mo-W/γ-Al_2O_3 catalyst exhibited the best performance for saturation of 1-MN. The introduction of NH3 remarkably inhibited the hydrogenation of 1-MN in the dynamic control area, but it had no effect in the thermodynamic control area. Besides, the mono-aromatics selectivity on the Ni-Mo-W and Ni-Mo catalysts was enhanced. However, it had little effect on the Ni-W and Co-Mo catalysts.Ge Panzhu Ren Liang Gao Xiaodong Li Dadong 2015China Petroleum Processing & Petrochemical Technology2015,17,4:4
17An analytical model for estimating soil temperature profiles on the Qinghai-Tibet Plateau of China显示文摘Soil temperature is a key variable in the control of underground hydro-thermal processes. To estimate soil temperature more accurately, this study proposed a solution method of the heat conduction equation of soil temperature(improved heat conduction model) by applying boundary conditions that incorporate the annual and diurnal variations of soil surface temperature and the temporal variation of daily temperature amplitude, as well as the temperature difference between two soil layers in the Tanggula observation site of the Qinghai-Tibet Plateau of China. We employed both the improved heat conduction model and the classical heat conduction model to fit soil temperature by using the 5 cm soil layer as the upper boundary for soil depth. The results indicated that the daily soil temperature amplitude can be better described by the sinusoidal function in the improved model, which then yielded more accurate soil temperature simulating effect at the depth of 5 cm. The simulated soil temperature values generated by the improved model and classical heat conduction model were then compared to the observed soil temperature values at different soil depths. Statistical analyses of the root mean square error(RMSE), the normalized standard error(NSEE) and the bias demonstrated that the improved model showed higher accuracy, and the average values of RMSE, bias and NSEE at the soil depth of 10–105 cm were 1.41°C, 1.15°C and 22.40%, respectively. These results indicated that the improved heat conduction model can better estimate soil temperature profiles compared to the traditional model.HU Guojie ZHAO Lin WU Xiaodong LI Ren WU Tonghua XIE Changwei QIAO Yongping SHI Jianzong CHENG Guodong 2016Journal of Arid Land2016,8,2:4
18Short-term Prediction of Ionospheric TEC Based on ARIMA Model显示文摘In order to achieve high short-term prediction accuracy of ionospheric TEC,first,we transform a seasonal time series for ionospheric Total Electron Content (TEC) into a stationary time series by seasonal differences and regular differences with a full consideration of the Multiplicative Seasonal model.Next,we use the Autoregressive Integrated Moving Average (ARIMA) model taken from time series analysis theory for modeling the stationary TEC values to predict the TEC series.Using TEC data from 2008 to 2012 provided by the Center for Orbit Determination in Europe (CODE) as sample data,we analyzed the precision of this method for prediction of ionospheric TEC values which vary from high to low latitudes during both quiet and active ionospheric periods.The effect of the TEC sample’s length on the predicted accuracy is analyzed,too.Results from numerical experiments show that during the ionospheric quiet period the average relative prediction accuracy for a six day time span reaches up to 83.3% with average prediction residual errors of about 0.18±1.9 TECu.During ionospheric active periods it changes to 86.6% with an average prediction residual error of about 0.69±2.6 TECu.For the quiet periods,above 90% of predicted residual is less than ±3 TECu while during active periods,it is only about 81%.The two periods show that that the higher the latitude,the higher the absolute precision,and the lower the predicted relative accuracy.In addition,the results show that prediction accuracy will improve with an increase of the TEC sample sequences length,but it will gradually reduce if the length exceeds the optimal length,about 30 days.On the other hand,with the same TEC sample,as the predicted days increase,the predictive accuracy decreases.Athough the predictive accuracy is not apparent at the beginning,it will be significantly reduced after 30 days.Xiaohong ZHANG Xiaodong REN Fengbo WU Qi LU 2019Journal of Geodesy and Geoinformation Science2019,2,1:4
19Ultrafast optical nonlinearity of blue-emitting perovskite nanocrystals显示文摘Perovskite nanocrystals(NCs) have strong nonlinear optical responses with a number of potential applications,ranging from upconverted blue-lasing to the tagging of specific cellular components in multicolor fluorescence microscopy. Here, we determine the one-photon linear absorption cross section of two kinds of blue-emitting perovskite NCs, i.e., CsPbCl_3 and CsPb(Cl_(0.53)Br_(0.47))_3, by utilizing femtosecond transient absorption spectroscopy. The wavelength-dependent nonlinear refraction and two-photon absorption have been measured at wavelengths from 620 to 720 nm by performing Z-scan measurements. The nonlinear optical responses of CsPb(Cl_(0.53)Br_(0.47))_3 are much more pronounced than those of CsPbCl_3 due to the larger structural destabilization of the former.JUNZI LI CAN REN XIN QIU XIAODONG LIN RUI CHEN CHENG YIN TINGCHAO HE 2018Photonics Research2018,6,6:3
20Progress of Jinping Underground laboratory for Nuclear Astrophysics(JUNA)显示文摘Jinping Underground laboratory for Nuclear Astrophysics(JUNA) will take the advantage of the ultra-low background of CJPL lab and high current accelerator based on an ECR source and a highly sensitive detector to directly study for the first time a number of crucial reactions occurring at their relevant stellar energies during the evolution of hydrostatic stars. In its first phase, JUNA aims at the direct measurements of^(25)Mg(p,γ)^(26)Al,^(19)F(p,α)^(16)O,^(13)C(α,n)^(16)O and ^(12)C(α,γ)^(16)O reactions. The experimental setup,which includes an accelerator system with high stability and high intensity, a detector system, and a shielding material with low background, will be established during the above research. The current progress of JUNA will be given.WeiPing Liu ZhiHong Li JiangJun He XiaoDong Tang Gang Lian Zhu An JianJun Chang Han Chen QingHao Chen XiongJun Chen ZhiJun Chen BaoQun Cui XianChao Du ChangBo Fu Lin Gan Bing Guo GuoZhu He Alexander Heger SuQing Hou HanXiong Huang Ning Huang BaoLu Jia LiYang Jiang Shigeru Kubono JianMin Li KuoAng Li Tao Li YunJu Li Maria Lugaro XiaoBing Luo HongYi Ma ShaoBo Ma DongMing Mei YongZhong Qian JiuChang Qin Jie Ren YangPing Shen Jun Su LiangTing Sun WanPeng Tan Isao Tanihata Shuo Wang Peng Wang YouBao Wang Qi Wu ShiWei Xu ShengQuan Yan LiTao Yang Yao Yang XiangQing Yu Qian Yue Sheng Zeng HuanYu Zhang Hui Zhang LiYong Zhang NingTao Zhang QiWei Zhang Tao Zhang XiaoPeng Zhang XueZhen Zhang ZiMing Zhang Wei Zhao Zuo Zhao Chao Zhou 2016Science China(Physics,Mechanics & Astronomy)2016,59,4:3
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