检索结果-南通市图书馆

Assessing current stocks and future sequestration potential of forest biomass carbon in Daqing Mountain Nature Reserve of Inner Mongolia, China

在线全文

学校读者我要写书评

暂无评论

Journal of Forestry Research 2016年第4期27卷 931-938页

作者： Yahui Sun li Meng lü tian Guoliang li Osbert Jianxin Sun College of Forest Science Beijing Forestry UniversityBeijing 100083 China Survey and Planning Institute of State Forestry Administration Beijing 100714 China Inner Mongolia Institute of Forest Monitoring and Planning Huhhot 010020 China Institute of Forestry and Climate Change Research Beijing Forestry University Beijing 100083 China

Assessment of regional forest carbon stocks and underlying controls is critical for guiding forest management in the context of carbon sequestration. We investigated the variations in tree biomass carbon stocks relating to forest types, and estimated the total tree biomass carbon stocks and projected gains through natural stand development by 2020 and 2050 in the Daqing Mountain Nature Reserve based on Category II data of the Forest Inventory of Inner Mongolia for the period ending 2008. Over a total area of 388,577 ha,this nature reserve currently stores an estimated 2221 Gg C in tree aboveground biomass alone, with potential to grow by more than 30 % to reach 2938 Gg C by 2020 and nearly double to 4092 Gg C by 2050 through natural development of the existing forest stands. The tree biomass carbon density and potential gain in tree biomass carbon stocks vary markedly among forest types and with stand *** variations in the potential change of tree biomass carbon density for the periods 2008–2020 and 2008–2050 among forest types partly reflect the varying relationships of tree biomass carbon density with stand age for different tree species, and partly are attributable to variations in the stand age structure among different forest types. Of the major forest types, the ranking of projected changes in tree biomass carbon density are not consistent with variations in the relationship between tree biomass carbon density and stand age, neither are they explainable by variations in stand age structures, implying the interactive effect between forest type and stand dynamics on temporal changes in tree biomass carbon density. Birch rank highest for future biomass carbon sequestration because of its dominance in cover area and better age structure for potential gain in tree biomass carbon stocks. Poplar and larch were out-performers compared to other forest types given their greater contribution to total tree biomass carbon stocks relative to their distributional

关键词： sequestration biomass stocks stand forests Reserve Birch projected gains anthropogenic

EFFECT OF Cu-Ni CONTENT ON THE CORROSION RESISTANCE OF(Cu-Ni)/(10NiO-90NiFe_2O_4)CERMET INERT ANODE FOR AlUMINUM ElECTROlYSIS

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English letters) 2008年第1期21卷 72-78页

作者： Z.l. tian Y.Q. lai J. li Y.X. liu School of Metallurgical Science and Engineering Central South University Changsha 410083 China

（Cu-Ni）/（10NiO-90NiFe204） cermet inert anodes containing metal Cu-Ni0, 5, 10, 15 and 20 wt pct were prepared and their corrosion resistance to Na3AlF6-Al2O3 melts was investigated. The results indicate that the content of metal Cu-Ni has little effect on the steady-state concentration of Ni in the electrolyte and the values could not be used to effectively differentiate their corrosion resistance. The steady-state concentration of Fe decreases from 304×10^-6 to 168×10^-6 and that of Cu increases from 21×10^-6 to 71×10^-6 with the content of metal Cu-Ni increasing from 0 to 20 wt pct. Post-examination shows that metallic phase Cu-Ni is corroded preferentially during electrolysis and many pores are left at the anode surface. Considering the corrosion resistance and electrical conductivity, the cermet containing metal Cu-Ni 5 wt pct should be selected and studied further.

关键词： Aluminum electrolysis Inert anode NiFe2O4 based cermet Corrosion resistance

MICROSTRUCTURE TRANSFORMATION IN THE WElDING HEAT AFFECTED ZONE OF 800MPa GRADE UlTRA FINE STRUCTURED STEEl

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English letters) 2004年第3期17卷 238-246页

作者： J.B. liu l.J. Hu Y.T.Wang Z. Q. liu K. Miao Z.l. tian Huazhong University of Science and Technology Wuhan 430074 China Technology Center of Wuhan Iron and Steel (Group) Corporation Wuhan 430080 China Central Iron and Steel Research Institute Beijing 100080 China

The transformation behavior and microstructure development in the heat affected zone(HAZ)of 800MPa grade ultra fine structured steel was *** was found that the HAZ has intermediate temperature transformation characteristics in a wide range of cooling rates,with the bainite sheaves consisting of bainite ferrite plates without carbide precipitation and retained austenite in the fast cooling *** relatively high cooling rates,which corresponded to low heat inputs,the hardness of the simulated HAZ was above that of the base *** the cooling rate was below 9C/s,the welding HAZ would have an obvious *** analysis of transformation rates in continuous cooling processes was completed by numerical differential *** result indicated that the microstructure transformation rate of the HAZ in 800MPa grade ultra fine structured steel changed sharply to slow speeds when the cooling time t8/5 is longer than 7s.

关键词： ultra fine structured steel weld heat affected zone transformation rate microstructure

The priority of management factors for reducing the yield gap of summer maize in the north of Huang-Huai-Hai region, China

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2021年第2期20卷 450-459页

作者： lIU Yue-e lI Yu-xin lU tian-fang XING Jin-feng XU tian-jun CAI Wan-tao ZHANG Yong ZHAO Jiuran WANG Rong-huan Beijing Key laboratory of Maize DNA Fingerprinting and Molecular Breeding Maize Research CenterBeijing Academy of Agriculture&Forestry SciencesBeijing 100097P.R.China

Understanding yield potential, yield gap and the priority of management factors for reducing the yield gap in current intensive maize production is essential for meeting future food demand with the limited resources. In this study, we conducted field experiments using different planting modes, which were basic productivity(CK), farmer practice(FP), high yield and high efficiency(HH), and super high yield(SH), to estimate the yield gap. Different factorial experiments(fertilizer, planting density, hybrids, and irrigation) were also conducted to evaluate the priority of individual management factors for reducing the yield gap between the different planting modes. We found significant differences between the maize yields of different planting modes. The treatments of CK, FP, HH, and SH achieved 54.26, 58.76, 65.77, and 71.99% of the yield potential, respectively. The yield gaps between three pairs: CK and FP, FP and HH, and HH and SH, were 0.76, 1.23 and 0.85 t ha^(–1), respectively. By further analyzing the priority of management factors for reducing the yield gap between FP and HH, as well as HH and SH, we found that the priorities of the management factors(contribution rates) were plant density(13.29%)>fertilizer(11.95%)>hybrids(8.19%)>irrigation(4%) for FP to HH, and hybrids(8.94%)>plant density(4.84%)>fertilizer(1.91%) for HH to SH. Therefore, increasing the planting density of FP was the key factor for decreasing the yield gap between FP and HH, while choosing hybrids with density and lodging tolerance was the key factor for decreasing the yield gap between HH and SH.

关键词： maize yield gap management factors priority hybrid plant density fertilizer irrigation

Effects of icariin on cGMP-specific PDE5 and cAMP-specific PDE4 activities

在线全文

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2003年第1期5卷 15-18页

作者： ZC Xin EK Kim CS lin WJ liu l tian YM Yuan J Fu Department of Urology the Ist Hospital Peking University Beijing 100034 China Department of life Science Pohang University of Science and Technology Pohang Korea Knuppe Molecular Urology laboratory Department of Urology UCSF USA

Aim: To clarify the mechanism of the therapeutic action of icariin on erectlile dysfunction (ED). Methods: PDE5 was isolated from the human platelet and PDE4 from the rat liver tissue using the FPlC system (Pharmacia, Milton Keynes, UK) and the Mono Q column. The inhibitory effects of icariin on PDE5 and PDE4 activities were investigated by the two-step radioisotope procedure with [3H]-cGMP/[3H]-cAMP. Papaverine served as the control drug. Results: Icariin and papaverine showed dose-dependent inhibitory effects on PDE5 and PDE4 activities. The IC50 of Icariin and papaverine on PDE5 were 0.432 μmol/l and 0.680μmol/l, respectively and those on PDE4, 73.50 μmol/l and 3.07μmol/l, respectively. The potencies of selectivity of icariin and papaverine on PDE5 (PDE4/PDE5 of IC50) were 167.67 times and 4.54 times, respectively. Conclusion: Icariin is a cGMP-specific PDE5 inhibitor that may be developed into an oral effective agent for the treatment of ED.

关键词： icariin PDE5 cGMP penile erection

“Slope-adsorption&plateau-pore filling”mechanism unlocking the potential of hard carbon anodes for“fast-charging&large-sized”batteries

在线全文

学校读者我要写书评

暂无评论

Science China Materials 2025年第1期68卷 309-311页

作者： tian liang Xiaoming Zhu Hubei Key laboratory of Radiation Chemistry and Functional Materials School of Nuclear Technology and Chemistry&BiologyHubei University of Science and TechnologyXianning 437100China

To date,there has been no report on fast-charging and Ahlevel sodium-ion batteries(SIBs)by utilizing thick hard carbon anodes that demonstrate prolonged cycling life and high areal capacity at high ***,the relationship among the complex structure of hard carbon,storage mechanism,and fastcharging performance in alkali-metal ion batteries has been a subject of ongoing debate[1,2].

关键词： mechanism charging utilizing

Progress of Deep Geological Survey Project under the China Geological Survey

在线全文

学校读者我要写书评

暂无评论

China Geology 2020年第1期3卷 153-172页

作者： Qing-tian lü Jia-yong Yan Xuan-hua Chen He-sheng Hou Wen-shi Wang Yu-le Hu Chinese Academy of Geological Sciences China Geological SurveyMinistry of Natural ResourcesBeijing 100037China SinoProbe Center Chinese Academy of Geological SciencesChina Geological SurveyMinistry of Natural ResourcesBeijing 100037China Institute of Exploration Technique Chinese Academy of Geological SciencesNanchang 330013China China University of Geosciences Wuhan 430074China

Serving as a way to understand the material composition,structure,and dynamic process of the Earth's interior,deep earth exploration is driven by not only mankind's pursuit of natural mysteries but also mankind's basic need to obtain resources and guarantee economic and social *** first phase of deep earth exploration of China(SinoProbe)was carried out from 2008 to 2016 and tremendous results were *** 2016,the China Geological Survey launched a Deep Geological Survey Project(also referred to as the Project)to continuously explore the deep *** on the national energy resources strategy,the Belt and Road Initiative,and major basic issues of the geological survey,the Project was carried out in Songliao Basin(an important energy base in China)and major geological boundaries and tectonic units including Qilian Mountains-tianshan Mountains and Qinzhou-Hangzhou juncture *** purpose of it is to reveal the process,structure,and forming patterns of the deep ore deposits and petroleum reservoirs,clarify the evolutionary pattern and controlling factors of Mesozoic environmental climate,and discover deep fine structures of key orogens,basins,and mountains by comprehensive geophysical exploration and scientific *** achievements have been obtained after more than three years of efforts,including a cumulative 1552 km of deep seismic reflection profiles and magnetotelluric profiles,an ultra-deep continental scientific crilling well,a scientific drilling pilot hole,and a magnetotelluric array and a portable broadband seismic array,both of which cover South ***,significant progress has been made in ultra-deep drilling technology,deep oil and gas discovery in Songliao Basin,and basic geological issues of Qilian Orogen and Qinzhou-Hangzhou juncture belt in South China,greatly accelerating the deep earth exploration in China and further consolidating China's position as a power in deep earth exploration.

关键词： Deep geological survey Deep oil and gas discovery Ultra-deep scientific drilling technology Songke No.2 well Qilian Mountains-tianshan Mountains Qinzhou-Hangzhou juncture belt Songliao Basin China

New progresses of fine-grained sediment gravity-flow deposits and their importance for unconventional shale oil and gas plays

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2025年第1期22卷 1-15页

作者： tian Yang Ying-lin liu State Key laboratory of Oil and Gas Reservoir Geology and Exploitation (Chengdu University of Technology) Institute of Sedimentary Geology Key laboratory of Deep-time Geography and Environment Reconstruction and Applications of Ministry of Natural Resources Chengdu University of Technology

Fine-grained sediments are widely distributed and constitute the most abundant component in sedimentary systems, thus the research on their genesis and distribution is of great significance. In recent years, fine-grained sediment gravity-flows(FGSGF) have been recognized as an important transportation and depositional mechanism for accumulating thick successions of fine-grained sediments. Through a comprehensive review and synthesis of global research on FGSGF deposition, the characteristics,depositional mechanisms, and distribution patterns of fine-grained sediment gravity-flow deposits(FGSGFD) are discussed, and future research prospects are clarified. In addition to the traditionally recognized low-density turbidity current and muddy debris flow, wave-enhanced gravity flow, lowdensity muddy hyperpycnal flow, and hypopycnal plumes can all form widely distributed FGSGFD. At the same time, the evolution of FGSGF during transportation can result in transitional and hybrid gravityflow deposits. The combination of multiple triggering mechanisms promotes the widespread development of FGSGFD, without temporal and spatial limitations. Different types and concentrations of clay minerals, organic matters, and organo-clay complexes are the keys to controlling the flow transformation of FGSGF from low-concentration turbidity currents to high-concentration muddy debris flows. Further study is needed on the interaction mechanism of FGSGF caused by different initiations, the evolution of FGSGF with the effect of organic-inorganic synergy, and the controlling factors of the distribution patterns of FGSGFD. The study of FGSGFD can shed some new light on the formation of widely developed thin-bedded siltstones within shales. At the same time, these insights may broaden the exploration scope of shale oil and gas, which have important geological significances for unconventional shale oil and gas.

关键词： Fine-grained sediment gravity-flow Depositional mechanism Transportation and evolution Distribution pattern Shale oil and gas

Upper Bounds on the Multicolor Ramsey Numbers r_(k)(C_(4))

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2025年第1期41卷 286-294页

作者： tian-yu lI Qi-zhong lIN Center for Discrete Mathematics Fuzhou UniversityFuzhou 350108China

The multicolor Ramsey number r_(k)(C_(4))is the smallest integer N such that any k-edge coloring of KN contains a monochromatic C_(4).The current best upper bound of r_(k)(C_(4))was obtained by Chung(1974)and independently by Irving(1974),i.e.,r_(k)(C_(4))≤k^(2)+k+1 for all k≥*** is no progress on the upper bound since *** this paper,we improve the upper bound of r_(k)(C_(4))by showing that r_(k)(C_(4))≤k^(2)+k-1 for even k≥*** improvement is based on the upper bound of the Turan number ex(n,C4),in which we mainly use the double counting method and many novel ideas from Firke,Kosek,Nash,and Williford[***,Ser.B 103(2013),327-336].

关键词： Multicolor Ramsey number Turan number 4-cycle