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Variation in carbon,nitrogen and phosphorus partitioning between above-and belowground biomass along a precipitation gradient at Tibetan Plateau

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Journal of Mountain Science 2016年第4期13卷 661-671页

作者： hong jiang-tao WANG Xiao-dan WU Jian-bo Institute of Mountain Hazards and Environment Academy of Sciences of SciencesChengdu 610041China University of Chinese Academy of Sciences Beijing 100049China

Precipitation is a potential factor that significantly affects plant nutrient pools by influencing biomass sizes and nutrient concentrations. However, few studies have explicitly dissected carbon(C), nitrogen(N) and phosphorus(P) pools between above- and belowground biomass at the community level along a precipitation gradient. We conducted a transect(approx. 1300 km long) study of Stipa purpurea community in alpine steppe on the Tibet Plateau of China to test the variation of N pool of aboveground biomass/N pool of belowground biomass(AB/BB N) and P pool of aboveground biomass/P pool of belowground biomass(AB/BB P) along a precipitation gradient. The proportion of aboveground biomass decreased significantly from mesic to drier sites. Along the belt transect, the plant N concentration was relatively stable; thus, AB/BB N increased with moisture due to the major influences by above- and belowground biomass allocation. However, P concentration of aboveground biomass decreased significantly with increasing precipitation and AB/BB P did not vary with aridity because of the offset effect of the P concentration and biomass allocation. Precipitation gradients do decouple the N and P pool of a S. purpurea community along a precipitation gradient in alpine steppe. The decreasing of N:P in aboveground biomass in drier regions may indicate much stronger N limitation in more arid area.

关键词： Biomass allocation Nutrient concentration Qinghai-Tibetan Plateau Alpine steppe Stipa purpurea

C:N:P stoichiometry of perennial herbs’ organs in the alpine steppe of the northern Tibetan Plateau

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Journal of Mountain Science 2019年第9期16卷 2039-2047页

作者： MA Xing-xing hong jiang-tao WANG Xiao-dan College of Geographical Sciences Shanxi Normal University Linfen 041000 China Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041 China

The patterns of C:N:P stoichiometry across ecosystems are important in understanding biogeochemical processes. The stoichiometry of nutrients at the leaf and root level have been reported previously, but relationships of other plant organs, such as stems and the reproductive organs, remain unclear. We collected 228 samples of leaves, roots, stems and reproductive organs from 11 common plant species at 25 sites on the Tibetan Plateau to explore the relationships of C:N:P stoichiometry both within and across plant organs. The average C concentrations in the roots, leaves, stems and reproductive organs were 427.32, 410.51, 421.11 and 416.72 mg g-1, respectively. The shoot tissues(leaves, stems and reproductive organs) had significantly higher N and P concentrations than the roots. The N and P concentrations had a significant positive correlation within the same organ. The nutrient concentrations(N and P) and nutrient ratios(C:N, C:P and N:P) were significantly correlated across all pairwise organ combinations. Our data suggest that alpine perennial herbs share similar evolutionary histories and have constrained patterns of covariation for C concentrations, with differential patterns for N and P stoichiometry across organs. Our data also indicate that covarying sets of nutrient traits are consistent across environments and biogeographical regions and demonstrate convergent evolution in plant nutritional characteristics in extreme alpine environments.

关键词： Shoot tissues Chemical elements Biogeochemical process Alpine steppe Tibet Plateau

Concise synthesis of valuable chiral N-Boc-β-benzyl-β-amino acid via construction of chiral N-Boc-3-benzyl-5-oxoisoxazolidine through cross-metathesis/conjugate addition/oxidation

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Chinese Chemical Letters 2017年第2期28卷 471-475页

作者： hong-tao jiang Hao-Ling Gao Cheng-Sheng Ge College of Chemical Engineering Zhejiang University of Technology College of Chemistry and Materials Engineering Quzhou University

Valuable chiral N-Boc-β-benzyl-β-amino acid was concisely synthesized via construction of chiral NBoc-3-benzyl-5-oxoisoxazolidine through cross-metathesis/conjugate addition/*** of the starting materials for the synthesis of chiral N-Boc-β-benzyl-β-amino acid are cheap,and two-step short procedure make it easy for the rapid construction of various chiral β-arylmethyl-β-amino acids and important drugs,such as sitagliptin phosphate.

关键词： Synthetic methods Conjugate addition Organocatalysis Asymmetric catalysis Enantioselective

Freeze-thaw process induced by increased precipitation affects root growth of alpine steppe on the Tibetan Plateau

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Journal of Mountain Science 2023年第10期20卷 3010-3017页

作者： QIN Xiao-jing NIE Xiao-jun WANG Xiao-dan hong jiang-tao School of Surveying and Land Information Engineering Henan Polytechnic UniversityJiaozuo 454003China Key Laboratory of Mountain Environment Evolution and Regulation Institute and Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 640016China

The response of vegetation productivity to precipitation is becoming a worldwide *** reports on responses of vegetation to precipitation trends are based on the growth *** the soil freeze/thaw process,the soil water phase and heat transport change can affect root growth,especially during the thawing process in early spring.A field experiment with increased precipitation(control,increased 25%and increased 50%)was conducted to measure the effects of soil water in early spring on above-and below-ground productivity in an alpine steppe over two growing seasons from June 2017 to September *** increased 50%treatment significantly increased the soil moisture at the 10 cm depth,there was no difference in soil moisture between the increased 25%treatment and the control in the growing season,which was not consistent in the freeze/thaw *** soil moisture during the non-growing season retarded root *** precipitation in the freezing-thawing period can partially offset the difference between the control and increased precipitation plots in both above-and below-ground biomass.

关键词： Freeze-thaw process Precipitation Root length Plant coverage Alpine grassland

Global patterns in above-ground net primary production and precipitation-use efficiency in grasslands

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Journal of Mountain Science 2018年第8期15卷 1682-1692页

作者： QIN Xiao-jing hong jiang-tao MA Xing-xing WANG Xiao-dan Key Laboratory of Mountain Surface Processes and Ecological Regulation Institute of Mountain Hazards and EnvironmentChinese Academy of ScienceChengdu 610041China University of Chinese Academy of Sciences Beijing 100049China College of Urban and Environment Sciences Shanxi Normal UniversityLinfen 041000China

The above-ground net primary production(ANPP) and the precipitation-use efficiency(PUE) regulate the carbon and water cycles in grassland ecosystems, but the relationships among the ANPP, PUE and precipitation are still controversial. We selected 717 grassland sites with ANPP and mean annual precipitation(MAP) data from 40 publications to characterize the relationships ANPP–MAP and PUE–MAP across different grassland types. The MAP and ANPP showed large variations across all grassland types, ranging from 69 to 2335 mm and 4.3 to 1706 g m^(-2), respectively. The global maximum PUE ranged from 0.19 to 1.49 g m^(-2) mm^(-1) with a unimodal pattern. Analysis using the sigmoid function explained the ANPP–MAP relationship best at the global scale. The gradient of the ANPP–MAP graph was small for arid and semi-arid sites(MAP <400 mm). This study improves our understanding of the relationship between ANPP and MAP across dry grassland ecosystems. It provides new perspectives on the prediction and modeling of variations in the ANPP for different grassland types along precipitation gradients.

关键词： Litter decomposition Alpine communities Tea bag index Carbon cycle Above-ground net primary production Precipitation-use efficiency Sigmoid function Precipitation gradients

High-Temperature Oxidation Behavior of Vanadium,Titanium-Bearing Magnetite Pellet

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Journal of Iron and Steel Research International 2011年第8期18卷 14-19页

作者： HAN Gui-hong jiang tao ZHANG Yuan-bo HUANG Yan-fang LI Guang-hui School of Minerals Processing and Bioengineering Central South University Changsha 410083 Hunan China

By means of isothermal oxidation and chemical analysis, great importance was attached to the parameters that made effects on the oxidation degree of vanadium, titanium-bearing magnetite pellet in high-temperature processing （1 073- 1 323 K）. Based on the experimental data, oxidation kinetics of pellet was analyzed according to shrinking unreacted-core model subsequently. Experiment results display that the oxidation degree of pellet increases with increasing of oxidation time, oxidation temperature and oxygen content, as well as shrinking of pellet diameter. Under the condition of oxidation time 20 min, oxidation temperature 1223 K, oxygen content 15%, and pellet diameter 12 mm, oxidation degree of pellet reaches 92.92%. The analysis of oxidation kinetics indicates that oxidation process of pellet is controlled by chemical reaction with activation energy 68.64 kJ/mol at a relatively lower temperature （1073-1 173 K）. Oxidation process of pellet is mixed-controlled by chemistry reaction and diffusion with activation energy 39.66 kJ/mol in the temperature range of 1 173-1 273 K. When oxidation temperature is higher than 1 273 K, the limited link of oxidation reaction is the diffusion control with the activation energy 20.85 kJ/mol. These results can serve as a reference to the production of vanadium, titanium-hearing magnetite pellet.

关键词： vanadium titanium-bearing magnetite oxidation degree pellet shrinking unreaeted-core model oxidation kinetics

Impacts of warming on root biomass allocation in alpine steppe on the north Tibetan Plateau

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Journal of Mountain Science 2017年第8期14卷 1615-1623页

作者： MA Xing-xing YAN Yan hong jiang-tao LU Xu-yang WANG Xiao-dan Key Laboratory of Mountain Surface Processes and Ecological Regulation Institute of Mountain Hazards and EnvironmentChinese Academy of Sciences University of Chinese Academy of Sciences

Biomass is an important component of global carbon cycling and is vulnerable to climate change. Previous studies have mainly focused on the responses of aboveground biomass and phenology to warming, while studies of root architecture and of root biomass allocation between coarse and fine roots have been scarcely reported in grassland ecosystems. We conducted an open-top-chamber warming experiment to investigate the effect of potential warming on root biomass and root allocation in alpine steppe on the north Tibetan Plateau. The results showed that Stipa purpurea had significantly higher total root length, root surface area and tips than Carex moocroftii. However,there were no differences in total root volume, mean diameter and forks for the two species. Warming significantly increased total root biomass(27.60%), root biomass at 0–10 cm depth(27.84%) and coarse root biomass(diameter > 0.20 mm, 57.68%) in the growing season(August). However, warming had no significant influence on root biomass in the non-growing season(April). Root biomass showed clear seasonalvariations: total root biomass, root biomass at 0–10 cm depth and coarse root biomass significantly increased in the growing season. The increase in total root biomass was due to the enhancement of root biomass at 0–10 cm depth, to which the increase of coarse root biomass made a great contribution. This research is of significance for understanding biomass allocation, carbon cycling and biological adaptability in alpine grassland ecosystems under future climate change.

关键词： Coarse root Fine root Root architecture Warming Climate change Open-top chambers

Constrained clustering with weak label prior

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Frontiers of Computer Science 2024年第3期18卷 117-132页

作者： Jing ZHANG Ruidong FAN hong tao Jiacheng jiang Chenping HOU College of Sciences National University of Defense TechnologyChangsha 410073China

Clustering is widely exploited in data *** has been proved that embedding weak label prior into clustering is effective to promote its *** researches mainly focus on only one type of ***,in many real scenarios,two kinds of weak label prior information,e.g.,pairwise constraints and cluster ratio,are easily obtained or already *** to incorporate them to improve clustering performance is important but rarely *** propose a novel constrained Clustering with Weak Label Prior method(CWLP),which is an integrated *** the unified spectral clustering model,the pairwise constraints are employed as a regularizer in spectral embedding and label proportion is added as a constraint in spectral *** approximate a variant of the embedding matrix more precisely,we replace a cluster indicator matrix with its scaled *** of fixing an initial similarity matrix,we propose a new similarity matrix that is more suitable for deriving clustering *** for the theoretical convergence and computational complexity analyses,we validate the effectiveness of CWLP through several benchmark datasets,together with its ability to discriminate suspected breast cancer patients from healthy *** experimental evaluation illustrates the superiority of our proposed approach.

关键词： clustering weak label prior cluster ratio pairwise constraints

Multiple advanced surgical techniques to treat acquired seminal duct obstruction

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Asian Journal of Andrology 2014年第6期16卷 912-916页

作者： hong-tao jiang Qian Yuan Yu Liu Zeng-Qin Liu Zhen-Yu Zhou Ke-Feng Xiao jiang-Gen Yang Department of Urology Shenzhen People's Hospital Shenzhen 518020 China Department of Laboratory Medicine Shenzhen People's Hospital Shenzhen 518020 China

The aim of this study was to evaluate the outcomes of multiple advanced surgical treatments （i.e. microsurgery, laparoscopic surgery and endoscopic surgery）for acquired obstructive azoospermia. We analyzed the surgical outcomes of 51 patients with suspected acquired obstructive azoospermia consecutively who enrolled at our center between January 2009 and May 2013. Modified vasoepididymostomy, laparoscopically assisted vasovasostomy and transurethral incision of the ejaculatory duct with holmium laser were chosen and performed based on the different obstruction sites. The mean postoperative follow-up time was 22 months （range： 9 months to 52 months）. Semen analyses were initiated at four postoperative weeks, followed by trimonthly （months 3, 6, 9 and 12） semen analyses, until no sperm was found at 12 months or until pregnancy was achieved. Patency was defined as 〉10,000 sperm m1-1 of semen. The obstruction sites, postoperative patency and natural pregnancy rate were recorded. Of 51 patients, 47 underwent bilateral or unilateral surgical reconstruction; the other four patients were unable to be treated with surgical reconstruction because of pelvic vas or intratesticular tubules obstruction. The reconstruction rate was 92.2% （47/51）, and the patency rate and natural pregnancy rate were 89.4% （42/47） and 38.1% （16/42）, respectively. No severe complications were observed. Using multiple advanced surgical techniques, more extensive range of seminal duct obstruction was accessible and correctable; thus, a favorable patency and pregnancy rate can be achieved.

关键词： azoospermia endoscopy laparoscopy male infertility microsurgery