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188篇 您的检索式:作者名="Yibo Wang"
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1Field experiment on a robust hierarchical metropolitan quantum cryptography network显示文摘A hierarchical metropolitan quantum cryptography network upon the inner-city commercial telecom fiber cables is reported in this paper. The seven-user network contains a four-node backbone net with one node acting as the subnet gateway, a two-user subnet and a single-fiber access link, which is realized by the Faraday-Michelson interferometer set-ups. The techniques of the quantum router, optical switch and trusted relay are assembled here to guarantee the feasibility and expandability of the quantum cryptography network. Five nodes of the network are located in the government departments and the secure keys generated by the quantum key distribution network are utilized to encrypt the instant video, sound, text messages and confidential files transmitting between these bureaus. The whole implementation including the hierarchical quantum cryptographic communication network links and the corresponding application software shows a big step toward the practical user-oriented network with a high security level.XU FangXing CHEN Wei WANG Shuang YIN ZhenQiang ZHANG Yang LIU Yun ZHOU Zheng ZHAO YiBo LI HongWei LIU Dong HAN ZhengFu GUO GuangCan 2009Chinese Science Bulletin2009,54,17:40
2Changes of net primary productivity in China during recent 11 years detected using an ecological model driven by MODIS data显示文摘网主要生产率(NPP ) 是陆上的碳周期的一个重要部件。精确地在中国印射 NPP 的空间时间的变化为全球碳骑车是关键的学习。在这研究,基于过程的北方的生态系统生产率模拟器(BEPS ) 被采用从 2000 ~ 2010 为时期在中国的生态系统学习 NPP 的变化。BEPS 模型首先用在在不同区域测量的典型流动地点和森林 NPP 测量的粗野主要生产率(GPP ) 被验证。然后,它与叶区域索引( LAI )被驾驶从中等分辨率成像分光辐射函数( MODIS )反射和陆地盖子产品和气象学的数据的 inversed 在 753 个国家基本气象学的车站从观察插入内推从1月1日在每日的时间步和 500 m 的空间分辨率模仿 NPP , 2000 到2010年12月31日。确认证明 BEPS 能在中国的不同区域捕获基于塔的 GPP 的季节的变化和森林 NPP 的空间可变性。年度 NPP 的估计的国家总数从 2.63 变化了到 2.84Pg C 獥吗?Yibo LIU Weimin JU Honglin HE Shaoqiang WANG Rui SUN Yuandong ZHANG 2013Frontiers of Earth Science2013,7,1:30
3Response of soil heat-water processes to vegetation cover on the typical permafrost and seasonally frozen soil in the headwaters of the Yangtze and Yellow Rivers显示文摘The response of soil temperature and moisture to vegetative cover in the active layer of permafrost and seasonally frozen soil were assessed and compared. Soil temperature and moisture, under a range of vegetation covers (92%, 65% and 30%) in the permafrost and vegetation covers (95%, 70%―80%, 40%―50% and 10%) in the seasonally frozen soil, were measured on a daily basis. A decline in vege-tation cover led to a decrease in the integral of freezing depth of active permafrost layer, but an increase in seasonally frozen soil. The maximum invasion depth and duration of the negative isotherm during the frozen period and of the positive isotherm during the non-frozen period clearly increased when vegetation cover declined. With a reduction of vegetation cover, the soil moisture in the active layer of the permafrost decreased for depths of 0.20―0.60 m, but increased for depths of 0.60―0.80 m, while for seasonally frozen soil, soil moisture of the entire profile (0.10―1.20 m) increased. Variation in vegetation cover alters soil heat-water processes, but the response to it is different between permafrost and seasonally frozen soil.HU HongChang WANG GenXu WANG YiBo LIU GuangSheng LI TaiBing REN DongXing 2009Chinese Science Bulletin2009,54,7:18
4Immunohistochemical prognostic markers of esophageal squamous cell carcinoma:a systematic review显示文摘Background: Esophageal squamous cell carcinoma(ESCC) is an aggressive malignancy, with a high incidence and poor prognosis. In the past several decades, hundreds of proteins have been reported to be associated with the prognosis of ESCC, but none has been widely accepted to guide clinical care. This study aimed to identify proteins with great potential for predicting prognosis of ESCC.Methods: We conducted a systematic review on immunohistochemical(IHC) prognostic markers of ESCC according to the 2009 Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA) Guidelines. Literature related to IHC prognostic markers of ESCC were searched from PubMed, Embase, Web of Science, and Cochrane Library until January 30 th, 2017. The risk of bias of these original studies was evaluated using the Quality in Prognosis Studies(QUIPS) tool.Results: We identified 11 emerging IHC markers with reproducible results, including eight markers [epidermal growth factor receptor(EGFR), Cyclin D1, vascular endothelial growth factor(VEGF), Survivin, Podoplanin, Fascin,phosphorylated mammalian target of rapamycin(p-mTOR), and pyruvate kinase M2(PKM2)] indicating unfavorable prognosis and 3 markers(P27, P16, and E-cadherin) indicating favorable prognosis of ESCC.Conclusion: Strong evidence supports that these 11 emerging IHC markers or their combinations may be useful in predicting prognosis and aiding personalized therapy decision-making for ESCC patients.Chunni Wang Jingnan Wang Zhaoli Chen Yibo Gao Jie He 2017Chinese Journal of Cancer2017,36,11:16
5Genome-wide Association Analyses Reveal the Genetic Basis of Stigma Exsertion in Rice显示文摘耻辱 exsertion,交配系统的米饭的一个关键决定因素,极大地在米饭贡献杂种优势的申请。尽管与耻辱 exsertion 联系的一些量的特点 loci 是印射或克隆的罚款,内在的基因建筑学仍然保持不清楚。我们用在 Oryza sativa 的 533 多样的就职描绘的 650 万 SNP 在耻辱 exsertion 和相关花的特点上执行了染色体宽的协会研究。我们识别了显著地与耻辱 exsertion 和相关特点,其三与三主要谷物尺寸基因 GS3, GW5,和 GW2 co 局部性被联系的 23 genomic loci。进一步的分析显示这三基因由控制小穗状花小穗和耻辱的尺寸和形状影响了耻辱 exsertion。GS3 和 GW5 的联合大部分定义耻辱 exsertion 和相关特点的层次。这二基因的选择在 O 的 subpopulations 之中导致了花的特点的特定的分布。sativa。低耻辱 exsertion 联合 gw5GS3 在栽培米饭变化的一半存在;因此,介绍 GW5gs3 联合进男无菌的线具有为改进混合米饭的种子生产的高潜力。Hao Zhou Pingbo Li WeiboXie Saddam Hussain Yibo Li Duo Xia Hu Zhao Shengyuan Sun Junxiao Chen Hong Ye Jun Hou Da Zhao Guanjun Gao Qinglu Zhang Gongwei Wang Xingming Lian Jinghua Xiao Sibin Yu Xianghua Li Yuqing He 2017Molecular Plant2017,10,4:15
6Clostridium butyricum regulates visceral hypersensitivity of irritable bowel syndrome by inhibiting colonic mucous low grade inflammation through its action on NLRP6显示文摘应力导致的内脏的超敏性在急躁的肠症候群(IBS ) 是相当普通的病人。Probiotics 玩在在 IBS 病人减少内脏的超敏性的一个重要角色。然而,机制清楚地没被阐明。在这研究,我们调查了像点头的受体 pyrin 的角色包含域的蛋白质(NLRP6 ) 6 由应力在 Clostridium 调整 butyricum 的 IBS 导致了。我们的结果证明 NLRP6 在 IBS 组冒号纸巾是下面调整的。另外, IL-18, IL-1, myeloperoxidase (军邮局) , d 乳的酸(D-LA ) ,和 CD172a 在 IBS 组是起来调整的结肠有粘液。在 NLRP6 基因是 silenced 以后, IL-18 和 IL-1 也被增加。病理学的分数建议了低发炎结肠有粘液而非终端回肠。水回避应力() 显示出内脏的超敏性到结肠的扩张。然而,有 Clostridium butyricum 的治疗颠倒了这些结果,施加有益的效果。在结论, Clostridium butyricum 可以由禁止低等级发炎在 IBS 的内脏的超敏性上施加一个有益的行动结肠通过它 NLRP6 上的行动有粘液。Kejia Zhao Leimin Yu Xi Wang Yibo He Bin Lu 2018Acta Biochimica et Biophysica Sinica2018,50,2:10
7Defects in Graphene:Generation,Healing,and Their Effects on the Properties of Graphene:A Review显示文摘Graphene has attracted immense investigation since its discovery.Lattice imperfections are introduced into graphene unavoidably during graphene growth or processing.These structural defects are known to significantly affect electronic and chemical properties of graphene.A comprehensive understanding of graphene defect is thus of critical importance.Here we review the major progresses made in defectrelated engineering of graphene.Firstly,we give a brief introduction on the types of defects in graphene.Secondly,the generation and healing of the graphene defects are summarized.Then,the effects of defects on the chemical,electronic,magnetic,and mechanical properties of graphene are discussed.Finally,we address the associated challenges and prospects on the future study of defects in graphene and other nanocarbon materials.Lili Liu Miaoqing Qing Yibo Wang Shimou Chen 2015Journal of Materials Science & Technology2015,31,6:9
8Effect of a thermokarst lake on soil physical properties and infiltration processes in the permafrost region of the Qinghai-Tibet Plateau, China显示文摘Changes in the hydrological processes in alpine soil constitute one of the several key problems encountered with studying watershed hydrology and ecosystem stability against the background of global warming. A typically developing thermokarst lake was chosen as a subject for a study using model simulation based on observations of soil physical properties, infiltration processes, and soil moisture. The results showed that the selected thermokarst lake imposed certain changes on the soil infiltration processes and, with the degree of impact intensifying, the initial infiltration rate decreased. The greatest reduction was achieved in the area of moderate impact. However, the stable infiltration rate and cumulative infiltration gradually increased in the surface layer at a depth of 10 and 20 cm, both decreasing initially and then increasing, which is correlated significantly with soil textures. Moreover, the cumulative infiltration changed in line with steady infiltration rate. Based on a comparative analysis, the Horton model helps better understand the effect on the soil infiltration processes of the cold alpine meadow close to the chosen thermokarst lake. In conclusion, the formation of the thermokarst lake reduced the water holding capacity of the alpine meadow soil and caused the hydraulic conductivity to increase, resulting in the reduction of runoff capacity in the area of the thermokarst lake.WANG YiBo GAO ZeYong WEN Jing LIU GuoHua GENG Di LI XiaoBing 2014Science China Earth Sciences2014,57,10:7
9Diet drives convergent evolution of gut microbiomes in bamboo-eating species显示文摘Gut microbiota plays a critical role in host physiology and health.The coevolution between the host and its gut microbes facilitates animal adaptation to its specific ecological niche.Multiple factors such as host diet and phylogeny modulate the structure and function of gut microbiota.However,the relative contribution of each factor in shaping the structure of gut microbiota remains unclear.The giant(Ailuropoda melanoleuca)and red(Ailurus styani)pandas belong to different families of order Carnivora.They have evolved as obligate bamboo-feeders and can be used as a model system for studying the gut microbiome convergent evolution.Here,we compare the structure and function of gut microbiota of the two pandas with their carnivorous relatives using 16S rRNA and metagenome sequencing.We found that both panda species share more similarities in their gut microbiota structure with each other than each species shares with its carnivorous relatives.This indicates that the specialized herbivorous diet rather than host phylogeny is the dominant driver of gut microbiome convergence within Arctoidea.Metagenomic analysis revealed that the symbiotic gut microbiota of both pandas possesses a high level of starch and sucrose metabolism and vitamin B12 biosynthesis.These findings suggest a diet-driven convergence of gut microbiomes and provide new insight into host-microbiota coevolution of these endangered species.Guangping Huang Xiao Wang Yibo Hu Qi Wu Yonggang Nie Jiuhong Dong Yun Ding Li Yan Fuwen Wei 2021Science China(Life Sciences)2021,64,1:6
10Large-scale blow spinning of heat-resistant nanofibrous air filters显示文摘Particulate matter(PM)pollution has become a serious problem worldwide and various kinds of nanofibrous filters aiming to solve the problem have been developed.It is urgent to remove PM from high-temperature pollution sources,such as industrial emissions,coal furnaces,and automobile exhaust gases.However,filtration at pollution sources remains challenging because most existing air filters are not resistant to high temperature.Herein,heat-resistant polyimide(PI)nanofibrous air filters are fabricated via a simple and scalable solution blow-spinning method.These air filters show excellent thermal stability at high temperature up to 420℃.They exhibit a filtration efficiency as high as 99.73%at ambient temperature and over 97%at 300℃.In addition,a field test shows that the filters remove>97%of PM from the car exhaust fumes.Hence,the blow-spun PI nanofibrous membranes combined with the facile preparation strategy have great potential in high temperature air filtration fields and other similar applications such as water purification and protein separation.Ziwei Li Jianan Song Yuanzheng Long Chao Jia Zhenglian Liu Lei Li Cheng Yang Junchen Liu Sen Lin Haiyang Wang Yibo Liu Minghao Fang Hui Wu 2020Nano Research2020,13,3:6
11Optical conductivity-based ultrasensitive mid-infrared biosensing on a hybrid metasurface显示文摘Optical devices are highly attractive for biosensing as they can not only enable quantitative measurements of analytes but also provide information on molecular structures.Unfortunately,typical refractive index-based optical sensors do not have sufficient sensitivity to probe the binding of low-molecular-weight analytes.Non-optical devices such as field-effect transistors can be more sensitive but do not offer some of the significant features of optical devices,particularly molecular fingerprinting.We present optical conductivity-based mid-infrared(mid-IR)biosensors that allow for sensitive and quantitative measurements of low-molecular-weight analytes as well as the enhancement of spectral fingerprints.The sensors employ a hybrid metasurface consisting of monolayer graphene and metallic nano-antennas and combine individual advantages of plasmonic,electronic and spectroscopic approaches.First,the hybrid metasurface sensors can optically detect target molecule-induced carrier doping to graphene,allowing highly sensitive detection of low-molecular-weight analytes despite their small sizes.Second,the resonance shifts caused by changes in graphene optical conductivity is a well-defined function of graphene carrier density,thereby allowing for quantification of the binding of molecules.Third,the sensor performance is highly stable and consistent thanks to its insensitivity to graphene carrier mobility degradation.Finally,the sensors can also act as substrates for surfaceenhanced infrared spectroscopy.We demonstrated the measurement of monolayers of sub-nanometer-sized molecules or particles and affinity binding-based quantitative detection of glucose down to 200 pM(36 pg/mL).We also demonstrated enhanced fingerprinting of minute quantities of glucose and polymer molecules.Yibo Zhu Zhaoyi Li Zhuang Hao Christopher DiMarco Panita Maturavongsadit Yufeng Hao Ming Lu Aaron Stein Qian Wang James Hone Nanfang Yu Qiao Lin 2018Light(Science & Applications)2018,7,1:6
12The RppC-AvrRppC NLR-effector interaction mediates the resistance to southern corn rust in maize显示文摘Southern corn rust(SCR),caused by the fungal pathogen Puccinia polysora,is a major threat to maize pro-duction worldwide.Efficient breeding and deployment of resistant hybrids are key to achieving durable control of SCR.Here,we report the molecular cloning and characterization of RppC,which encodes an NLR-type immune receptor and is responsible for a major SCR resistance quantitative trait locus.Further-more,we identified the corresponding avirulence effector,AvrRppC,which is secreted by P.polysora and triggers RppC-mediated resistance.Allelic variation of AvrRppC directly determines the effectiveness of RppC-mediated resistance,indicating that monitoring of AvrRppC variants in the field can guide the rational deployment of RppC-containing hybrids in maize production.Currently,RppC is the most frequently deployed SCR resistance gene in China,and a better understanding of its mode of action is crit-ical for extending its durability.Ce Deng April Leonard James Cahill Meng Lv Yurong Li Shawn Thatcher Xueying Li Xiaodi Zhao Wenjie Du Zheng Li Huimin Li Victor Llaca Kevin Fengler Lisa Marshall Charlotte Harris Girma Tabor Zhimin Li Zhiqiang Tian Qinghua Yang Yanhui Chen Jihua Tang Xintao Wang Junjie Hao Jianbing Yan Zhibing Lai Xiaohong Fei Weibin Song Jinsheng Lai Xuecai Zhang Guoping Shu Yibo Wang Yuxiao Chang Weiling Zhu Wei Xiong Juan Sun Bailin Li Junqiang Ding 2022Molecular Plant2022,15,5:6
13In vitro testicular organogenesis from human fetal gonads produces fertilization-competent spermatids显示文摘Unlike most organs that mature during the fetal period,the male reproductive system reaches maturity only at puberty with the commencement of spermatogenesis.Robust modelling of human testicular organogenesis in vitro would facilitate research into mechanisms of and factors affecting human spermatogenic failure and male fertility preservation in prepubertal tumor patients.Here,we report successful recapitulation of human testicular organogenesis in vitro from fetal gonadal ridge.Our model displayed the formation of mature seminiferous epithelium and self-renewing spermatogonia.Remarkably,in vitro-derived haploid spermatids have undergone meiotic recombination,and showed increased genetic diversity as indicated by genetic analysis.Moreover,these spermatids were able to fertilize oocytes and support subsequent blastocyst formation.The in vitro testicular organogenesis system described here will play an important role in elucidating the regulation of human testis development and maintaining male fertility in prepubertal cancer patients.Yan Yuan Laihua Li Qing Cheng Feiyang Diao Qiao Zeng Xiaoyu Yang Yibo Wu Hao Zhang Mingqian Huang Junqing Chen Quan Zhou Yunfei Zhu Rong Hua Jianyu Tian Xin Wang Zuomin Zhou Jie Hao Jinjin Yu Dong Hua Jiayin Liu Xuejiang Guo Qi Zhou Jiahao Sha 2020Cell Research2020,30,3:6
14Motility-based label-free detection of parasites in bodily fluids using holographic speckle analysis and deep learning显示文摘Parasitic infections constitute a major global public health issue.Existing screening methods that are based on manual microscopic examination often struggle to provide sufficient volumetric throughput and sensitivity to facilitate early diagnosis.Here,we demonstrate a motility-based label-free computational imaging platform to rapidly detect motile parasites in optically dense bodily fluids by utilizing the locomotion of the parasites as a specific biomarker and endogenous contrast mechanism.Based on this principle,a cost-effective and mobile instrument,which rapidly screens~3.2 mL of fluid sample in three dimensions,was built to automatically detect and count motile microorganisms using their holographic time-lapse speckle patterns.We demonstrate the capabilities of our platform by detecting trypanosomes,which are motile protozoan parasites,with various species that cause deadly diseases affecting millions of people worldwide.Using a holographic speckle analysis algorithm combined with deep learningbased classification,we demonstrate sensitive and label-free detection of trypanosomes within spiked whole blood and artificial cerebrospinal fluid(CSF)samples,achieving a limit of detection of ten trypanosomes per mL of whole blood(~five-fold better than the current state-of-the-art parasitological method)and three trypanosomes per mL of CSF.We further demonstrate that this platform can be applied to detect other motile parasites by imaging Trichomonas vaginalis,the causative agent of trichomoniasis,which affects 275 million people worldwide.With its costeffective,portable design and rapid screening time,this unique platform has the potential to be applied for sensitive and timely diagnosis of neglected tropical diseases caused by motile parasites and other parasitic infections in resource-limited regions.Yibo Zhang Hatice Ceylan Koydemir Michelle M.Shimogawa Sener Yalcin Alexander Guziak Tairan Liu Ilker Oguz Yujia Huang Bijie Bai Yilin Luo Yi Luo Zhensong Wei Hongda Wang Vittorio Bianco Bohan Zhang Rohan Nadkarni Kent Hill Aydogan Ozcan 2018Light(Science & Applications)2018,7,1:6
15A reciprocal inhibitory module for Pi and iron signaling显示文摘Phosphorous(P)and iron(Fe),two essential nutrients for plant growth and development,are highly abundant elements in the earth's crust but often display low availability to plants.Due to the ability to form insoluble complexes,the antagonistic interaction between P and Fe nutrition in plants has been noticed for decades.However,the underlying molecular mechanism modulating the signaling and homeostasis between them re-mains obscure.Here,we show that the possible iron sensors HRZs,the iron deficiency-induced E3 ligases,could interact with the central regulator of phosphate(Pi)signaling,PHR2,and prompt its ubiquitination at lysine residues K319 and K328,leading to its degradation in rice.Consistent with this,the hrzs mutants dis-played a high Pi accumulation phenotype.Furthermore,we found that iron deficiency could attenuate Pi star-vation signaling by inducing the expression of HRZs,which in turn trigger PHR2 protein degradation.Inter-estingly,on the other hand,rice PHRs could negatively regulate the expression of HRZs to modulate iron deficiency responses.Therefore,PHR2 and HRZs form a reciprocal inhibitory module to coordinate Pi and iron signaling and homeostasis in rice.Taken together,our results uncover a molecular link between Pi and iron master regulators,which fine-tunes plant adaptation to Pi and iron availability in rice.Meina Guo Wenyuan Ruan Yibo Zhang Yuxin Zhang Xueqing Wang Zhenhui Guo Long Wang Tian Zhou Javier Paz-Ares Keke Yi 2022Molecular Plant2022,15,1:5
16Follistatin-like protein 1 plays a tumor suppressor role in clear-cell renal cell carcinoma显示文摘Background:We previously showed that the expression of follistatin-like protein 1(FSTL1)was significantly down-regulated in metastatic clear-cell renal cell carcinoma(ccRCC).In this study,we aimed to characterize the role of FSTL1 in the development of ccRCC.Methods:The effects of FSTL1 on cell activity and cell cycle were investigated in ccRCC cell lines with altered FSTL1 expression.Gene expression microarray assays were performed to identify the major signaling pathways affected by FSTL1 knockdown.The expression of FSTL1 in ccRCC and its effect on postoperative prognosis were estimated in a cohort with 89 patients.Results:FSTL1 knockdown promoted anchorage-independent growth,migration,invasion,and cell cycle of ccRCC cell lines,whereas FSTL1 overexpression attenuated cell migration.FSTL1 knockdown up-regulated nuclear factor-κB(NF-κB)and hypoxia-inducible factor(HIF)signaling pathways,increased epithelial-to-mesenchymal transition,up-regulated interleukin-6 expression,and promoted tumor necrosis factor-α-induced degradation of NF-κB inhibitor(IκBα)in ccRCC cell lines.FSTL1 immunostaining was selectively positive in epithelial cytoplasm in the loop of Henle,and positive rate of FSTL1 was significantly lower in ccRCC tissues than in adjacent renal tissues(P<0.001).The mul-tivariate Cox regression analysis showed that the intratumoral FSTL1 expression conferred a favorable independent prognosis with a hazard ratio of 0.325(95%confidence interval 0.118-0.894).HIF-2αexpression was negatively cor-related with FSTL1 expression in ccRCC specimens(r=−0.229,P=0.044).Intratumoral expression of HIF-2α,rather than HIF-1α,significantly predicted an unfavorable prognosis in ccRCC(log-rank,P=0.038).Conclusions:FSTL1 plays a tumor suppression role possibly via repressing the NF-κB and HIF-2αsignaling pathways.To increase FSTL1 expression might be a candidate therapeutic strategy for metastatic ccRCC.Yan Liu Xiaojie Tan Wenbin Liu Xi Chen Xiaomei Hou Dan Shen Yibo Ding Jianhua Yin Ling Wang Hongwei Zhang Yongwei Yu Jianguo Hou Timothy C.Thompson Guangwen Cao 2018Cancer Communications2018,38,1:5
17The pulsed high magnetic field facility and scientific research at Wuhan National High Magnetic Field Center显示文摘Wuhan National High Magnetic Field Center(WHMFC)at Huazhong University of Science and Technology is one of the top-class research centers in the world,which can offer pulsed fields up to 90.6 T with different field waveforms for scientific research and has passed the final evaluation of the Chinese government in 2014.This paper will give a brief introduction of the facility and the development status of pulsed magnetic fields research at WHMFC.In addition,it will describe the application development of pulsed magnetic fields in both scientific and industrial research.Xiaotao Han Tao Peng Hongfa Ding Tonghai Ding Zengwei Zhu Zhengcai Xia Junfeng Wang Junbo Han Zhongwen Ouyang Zhenxing Wang Yibo Han Houxiu Xiao Quanliang Cao Yiliang Lv Yuan Pan Liang Li 2017Matter and Radiation at Extremes2017,2,6:5
18Influences of the degradation of swamp and alpine meadows on CO_2 emission during growing season on the Qinghai-Tibet Plateau显示文摘CO2 emission fluxes of two types of ecosystem, swamp meadow and alpine meadow, in the Fenghuo- shan region of the Qinghai-Tibet Plateau were studied by the static chamber-portable infrared chro- matographic method. The results showed that there was large difference in the CO2 emission fluxes between the two ecosystems and in the same ecosystem of different degradation degrees. CO2 emis- sion flux of the swamp meadow gradually decreased with increasing degradation degree, while that of the alpine meadow gradually increased with increasing degradation degree except in May. The CO2 emission flux of undegraded swamp meadow was 65.1%―80.3% higher than that of undegraded alpine meadow; and the CO2 emission flux of moderately degraded swamp meadow was 22.1%―67.5% higher than that of alpine meadow; but the CO2 emission flux of severely degraded alpine meadow was 14.3%―29.5% higher than that of swamp meadow. The soil moisture content and temperature in the upper 5 cm soil layer and above-ground biomass were significantly correlated with the CO2 emission fluxes and regarded as the main environment factors to control the CO2 emission.WANG JunFeng WANG GenXu WANG YiBo LI YuanShou 2007Chinese Science Bulletin2007,52,18:5
19A Modular DC/DC Photovoltic Generation System for HVDC Grid Connection显示文摘A modular DC/DC conversion system with distributed MPPT and centralized step-up converter for photovoltaic energy integrated into HVDC grids is proposed in this paper.The conversion system consists of two power stages,with MPPT converter as the first stage and a step-up converter as the second stage.Both stages are modular structures.For the distributed MPPT stage,interleaved boost topology is utilized to effectively reduce the input and output ripples without adding extra components.For the centralized step-up stage,narrow-switching-frequency-variation LLC topology is employed,with the modules being configured as input-parallel-output-series structure.Full-range soft-switching property is achieved in the LLC stage to minimize switching losses.Theoretical analysis is carried out for the system voltage gain and design principles.Simulation and experimental results of a 3kW prototype system are presented to verify the theoretical analysis of the proposed system.Guoen Cao Kai Sun Siyue Jiang Shilei Lu Yibo Wang 2018Chinese Journal of Electrical Engineering2018,4,2:5
20Atmospheric deposition of inorganic nitrogen in a semi-arid grassland of Inner Mongolia, China显示文摘Due to increasing global demand for crop production and energy use, more and more reactive nitrogen(Nr) has been generated and emitted to the environment. As a result, global atmospheric nitrogen(N) deposition has tripled since the industrial revolution and the ecological environment and human health have been harmed. In this study, we measured dry and wet/bulk N deposition from July 2013 to December 2015 in a semi-arid grassland of Duolun County, Inner Mongolia, China. The samples of dry and wet/bulk N deposition were collected monthly with a DELTA(DEnuder for Long Term Atmospheric sampling) system and with Gradko passive samplers and a precipitation gauge. The measured results show that the annual mean concentrations of NH_3, NO_2, HNO_3, particulate NH_4^+(pNH_4^+) and particulate NO_3^-(pNO_3^-) in atmosphere were 2.33, 1.90, 0.18, 1.42 and 0.42 μg N/m3, respectively, and that the annual mean volume-weighted concentrations of NH_4^+-N and NO_3^--N in precipitation were 2.71 and 1.99 mg N/L, respectively. The concentrations of Nr components(including NH_3, NO_2, HNO_3, p NH_4^+, pNO_3^-, NH_4^+-N and NO_3^--N) exhibited different seasonal variations. Specifically, NO_2 and HNO_3 exhibited higher concentrations in autumn than in summer, while the other Nr components(NH_3, pNH_4^+, pNO_3^-, NH_4^+-N and NO_3^--N) showed the highest values in summer. Based on measured concentrations of Nr components and their deposition velocities estimated using the GEOS-Chem global atmospheric chemical transport model, the calculated annual mean dry deposition fluxes were 3.17, 1.13, 0.63, 0.91 and 0.36 kg N/(hm^2·a) for NH_3, NO_2, HNO_3, p NH_4^+ and pNO_3^-, respectively, and the calculated annual mean wet/bulk deposition fluxes were 5.37 and 3.15 kg N/(hm^2·a) for NH_4^+-N and NO_3^--N, respectively. The estimated annual N deposition(including dry N deposition and wet/bulk N deposition) reached 14.7 kg N/(hm^2·a) in grassland of Duolun County, approaching to the upper limit of the N critical load(10–15 kg N/(hm^2·a)). Dry and wet/bulk deposition fluxes of all Nr components(with an exception of HNO_3) showed similar seasonal variations with the maximum deposition flux in summer and the minimum in winter. Reduced Nr components(e.g., gaseous NH_3 and p NH_4^+ in atmosphere and NH_4^+-N in precipitation) dominated the total N deposition at the sampling site(accounted for 64% of the total N deposition), suggesting that the deposited atmospheric Nr mainly originated from agricultural activities. Considering the projected future increases in crop and livestock production in Inner Mongolia, the ecological and human risks to the negative effects of increased N deposition could be increased if no mitigation measures are taken.ZHANG Yibo XU Wen WEN Zhang WANG Dandan HAO Tianxiang TANG Aohan LIU Xuejun 2017Journal of Arid Land2017,9,6:5
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