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Full-solution-processed high mobility zinc-tin-oxide thin-film-transistors

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Science China(Technological Sciences) 2016年第9期59卷 1407-1412页

作者： zhang YunGe HUANG GenMao DUAN Lian DONG GuiFang zhang deqiang QIU Yong Key Lab of organic Optoelectronics & Molecular Engineering of ministry of Education Department of Chemistry Tsinghua University

The full solution-processed oxide thin-film-transistors(TFTs) have the advantages of transparency, ease of large-area fabrication, and low cost, offering great potential applications in switching and driving fields, and attracting extensive research interest. However, the performance of the solution-processed TFTs is generally lower than that of the vacuum-deposited ones. In this article, the full-solution processed TFTs with zinc-tin-oxide(ZTO) semiconductor and aluminium(Al_2O_3) dielectrics were fabricated, and their mobilities in the saturation region are high. Besides, the effect of the Al_2O_3 dielectrics' preparation technology on ZTO TFTs' performance was studied. Comparing the ZTO TFTs using the spin-coated Al_2O_3 dielectrics of 1–4 layers, the ZTO TFT with 3-layer Al_2O_3 dielectrics achieved the optimal performance as its field-effect carrier mobility in the saturation region is 112 cm^2/V s, its threshold voltage is 2.4 V, and its on-to-off current ratio is 2.8×105. This is also the highest reported carrier mobility of the solution-processed ZTO TFTs.

关键词： solution-processed ZTO TFT Al_2O_3 preparation technology

Highly efficient hybrid warm white organic light-emitting diodes using a blue thermally activated delayed fluorescence emitter: exploiting the external heavy-atom effect

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Light(Science & Applications) 2015年第1期4卷 562-568页

作者： Dongdong zhang Lian Duan Yunge zhang Minghan Cai deqiang zhang Yong Qiu Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education Department of ChemistryTsinghua UniversityBeijing 100084China

To attain high efficiencies in hybrid white organic light-emitting diodes(WOLEDs),mutual quenching of the fluorophors and phosphors should be *** have been devoted to reducing the triplet quenching of phosphors;however,the quenching of fluorophors by the external heavy-atom effect(EHA)introduced by the phosphors is often ***,we observed that conventional fluorophors and fluorophors with thermally activated delayed fluorescence(TADF)behave differently in the presence of EHA *** efficiencies of the conventional fluorophors suffer greatly from the EHA,whereas the TADF fluorophors exhibit negligible changes,which makes TADF materials ideal fluorophors for hybrid *** using a blue TADF fluorophor and an orange phosphor achieve a maximum forward viewing external quantum efficiency of 19.6%and a maximum forward viewing power efficiency of 50.2 lm W^(-1),among the best values for hybrid *** report is the first time that the EHA effect has been considered in hybrid WOLEDs and that a general strategy toward highly efficient hybrid WOLEDs with simple structures is proposed.

关键词： external heavy-atom effect hybrid white OLEDs thermally activated delayed fluorescenceexternal heavy-atom effect hybrid white OLEDs thermally activated delayed fluorescence

Study of Cracking Mechanism and Wear Resistance in Laser Cladding Coating of Ni-based Alloy

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Chinese Journal of Mechanical Engineering 2021年第5期34卷 259-272页

作者： Zhenglei Yu Lunxiang Li deqiang zhang Guangfeng Shi Guang Yang Zezhou Xu Zhihui zhang Key Lab of Bionic Engineering Ministry of EducationJilin UniversityChangchun 130022China State Key Laboratory of Automotive Simulation and Control Jilin UniversityChangchun 130022China College of Mechanical and Electric Engineering Changchun University of Science and TechnologyChangchun 130022China College of Mechanical Engineering and Automation Liaoning University of TechnologyJinzhou 121001China Key Laboratory of Fundamental Science for National Defense of Aeronautical Digital Manufacturing Process Shenyang Aerospace UniversityShenyang 110136China

Nickel-based alloy coatings were widely used for the remanufacturing of dies and moulds by laser cladding,but the crack sensitivity would be increase due to the higher strength and hardness,which reduced the wear resistance of Ni-based *** this paper,Ni-based coatings with the addition of a plastic phase(an austenitic stainless net)were prepared using laser cladding technology,and the CeO_(2)was added in cladding *** cracking mechanism,microhardness,microstructure,phase composition,and wear properties were *** relationship between thermal stress and the elastic and plastic fracture had been developed from the standpoint of fracture mechan-ics and thermal elastic fracture *** fracture criterion of the nickel-based coating was obtained,and the study has shown that the crack sensitivity could be reduced by decreasing the thermal expansion coefficientΔα.Thus,a new method was proposed,which the stainless steel nets were prefabricated on the *** was found that the number of cracks reduced significantly with the addition of stainless steel *** the stainless steel net with 14 mesh was added in Ni-based coatings,the average microhardness of nickel composite coating was 565 HV_(0.2),which was 2.6 times higher than that of the 45 steel *** the rare earth oxide 4 wt.%CeO_(2)and stainless steel net were added in the Ni-based coating reducing the microhardness(the average microhardness is 425 HV_(0.2)),the wear resistance of it improved *** wear volume of Ni-based composite coating was 0.56×10^(−5) mm^(3)·N^(−1)·m^(−1),which was 85.1%lower than that of 45 *** experiment results have shown that the Nickel-based composite coating is equipped with low crack sensitivity and high abrasive resistance with austenitic stainless net and the rare earth oxide 4 wt.%*** research offers an efficient solution to produce components with low crack susceptibility and high wear-resistance coatings fabricated

关键词： Laser cladding Wear resistance Crack sensitivity Stainless steel net Rare earth oxide

Changes in leaf nutrient traits and photosynthesis of four tree species: effects of elevated [CO_(2)], N fertilization and canopy positions

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Journal of Plant Ecology 2012年第4期5卷 376-390页

作者： Juxiu Liu deqiang zhang Guoyi Zhou Honglang Duan Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems South China Botanical GardenChinese Academy of SciencesGuangzhou 510650China

Aims Leaf traits of trees exposed to elevated[CO_(2)]in association with other environmental factors are poorly understood in tropical and subtropical *** goal was to investigate the impacts of elevated[CO_(2)]and N fertilization on leaf traits in southern *** Four tree species,Schima superba *** Champ.(***),Ormosia pinnata(Lour.)Merr(***),Castanopsis hystrix ***.(***)and Acmena acuminatissima(Blume)*** Perry(***)were studied in a factorial combination of atmospheric[CO_(2)](ambient at~390μmol mol^(-1)and elevated[CO_(2)]at~700μmol mol^(-1))and N fertilization(ambient and ambient+100 kg N ha^(-1)year^(-1))in open-top chambers in southern China for 5 *** mass per unit leaf area(LMA),leaf nutrient concentration and photosynthesis(A_(sat))were *** Findings Results indicated that leaf traits and photosynthesis were affected differently by elevated[CO_(2)]and N fertilization among ***[CO_(2)]decreased LMA in all species,while N fertilization did not affect *** mass-based N concentration(N_(M))was significantly greater in *** and *** grown in elevated[CO_(2)]but was lower in *** mass-based P concentration(P_(M))was significantly greater in *** and *** exposed to elevated[CO_(2)]but was lower in ***.N fertilization significantly increased P_(M) in *** but decreased P_(M) in *** stimulation in ***,*** and *** was sustained after 5 years of CO_(2)fumigation.N fertilization did not modify the effects of elevated[CO_(2)]on *** traits(N_(M),N_(A),P_(M),P_(A))and light-saturated photosynthesis were decreased from the upper to lower *** position did not alter the responses of leaf traits and photosynthesis to elevated[CO_(2)].Results suggest that photosynthetic stimulation by elevated[CO_(2)]in native species in subtropical regions may be sustained in th

关键词： photosynthesis elevated CO_(2) nitrogen phosphorus subtropical China

Rate constants for the reaction of hydroxyl radicals with HFC-134a

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Journal of Environmental Sciences 1997年第3期9卷 108-112页

作者： zhang deqiang Zhong Jinxian Qiu Lianxiong Research Center for Eco Environmental Sciences Chinese Academy of SciencesBeijing 100085China Graduate School of the University of Science and Technology of China Beijing 100039China

Rate constants for the reaction of hydroxyl radicals with HFC 134a (CH 2FCF 3) have been measured by the discharge flow resonance fluorescence (DF RF) technique over the temperature range 288—370 K. The derived Arrhenius equation is: k″ =(1.27±0.16)×10 -12 exp(-(1662±41)/ T )cm 3/(mol·s). The tropospheric lifetime of HFC 134a is estimated to be 10.5 years, which is in excellent agreement with the most recent results.

关键词： hydroxyl radicals HFC 134a (CH 2FCF 3) discharge flow resonance fluorescence reaction kinetics.

Preparation and spectral characteristics of anthracene/tetracene mixed crystals

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Science China Chemistry 2009年第2期52卷 181-187页

作者： LI HuiPing DUAN Lian zhang deqiang DONG GuiFang WANG LiDuo QIU Yong Key Lab of Organic Optoelectronics&Molecular Engineering of Ministry of Education Department of ChemistryTsinghua Univer-sityBeijing 100084China

A series of tetracene-doped anthracene crystals with different doping concentrations(the highest mo-lar ratio 100:1) are grown from *** structures and optical characteristics of the above mixed crystals are investigated at room *** changing the doping concentrations,the fluorescence can be adjusted from blue-green to green and even to *** emission spectra of anthracene/tetracene(An/Te) mixed crystals reveal the sensitized fluorescence of tetracene and the partial quenching of anthracene *** data of transient photoluminescence(PL) decays illus-trate that in An/Te mixed crystals,the decay of anthracene becomes faster,while the PL lifetime of tet-racene is longer than that of the tetracene single *** above experimental results suggest that there is excitation energy transfer from anthracene to tetracene in the mixed crystals.

关键词： anthracene tetracene organic mixed crystals fluorescence spectrum energy transfer

Effect of N and P addition on soil organic C potential mineralization in forest soils in South China

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Journal of Environmental Sciences 2008年第9期20卷 1082-1089页

作者： OUYANG, Xuejun ZHOU, Guoyi HUANG, Zhongliang ZHOU, Cunyu LI, Jiong SHI, Junhui zhang, deqiang South China Botanical Garden Chinese Academy of Sciences Guangzhou 510650 China College of Horticulture and Gardening Yangtze University Jingzhou 434025 China Xinjiang Academy of Forest Sciences Urumqi 830002 China

Atmospheric nitrogen deposition is at a high level in some forests of South China. The effects of addition of exogenous N and P on soil organic carbon mineralization were studied to address: (1) if the atmospheric N deposition promotes soil C storage through decreasing mineralization; (2) if the soil available P is a limitation to organic carbon mineralization. Soils (0–10 cm) was sampled from monsoon evergreen broad-leaved forest (MEBF), coniferous and broad-leaved mixed forest (CBMF), and Pinus massoniana...

关键词： addition inorganic N available P mineralization soil organic C South China

Rates of litter decomposition in terrestrial ecosystems:global patterns and controlling factors

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Journal of Plant Ecology 2008年第2期1卷 85-93页

作者： deqiang zhang Dafeng Hui Yiqi Luo Guoyi Zhou South China Institute of Botany Chinese Academy of SciencesGuangzhou 510650China Department of Botany and Microbiology University of OklahomaNormanOK 73019USA Department of Biological Sciences Tennessee State University3500 John A.Merritt Blvd.NashvilleTennessee 37209USA

Aims We aim to construct a comprehensive global database of litter decomposition rate(k value)estimated by surface floor litterbags,and investigate the direct and indirect effects of impact factors such as geographic factors(latitude and altitude),climatic factors(mean annual tempePlrature,MAT;mean annual precipitation,MAP)and litter quality factors(the contents of N,P,K,Ca,Mg and C:N ratio,lignin:N ratio)on litter *** We compiled a large data set of litter decomposition rates(k values)from 110 research sites and conducted simple,multiple regression and path analyses to explore the relationship between the k values and impact factors at the global *** findings The k values tended to decrease with latitude(LAT)and lignin content(LIGN)of litter but increased with temperature,precipitation and nutrient concentrations at the large spatial *** factor such as climate,litter quality and geographic variable could not explain litter decomposition rates ***,the combination of total nutrient(TN)elements and C:N accounted for 70.2%of the variation in the litter decomposition *** combination of LAT,MAT,C:N and TN accounted for 87.54%of the variation in the litter decomposition *** results indicate that litter quality is the most important direct regulator of litter decomposition at the global *** data synthesis revealed significant relationships between litter decomposition rates and the combination of climatic factor(MAT)and litter quality(C:N,TN).The global-scale empirical relationships developed here are useful for a better understanding and modeling of the effects of litter quality and climatic factors on litter decomposition rates.

关键词： climatic factors geographic factors litter decomposition rate litter quality path analysis terrestrial ecosystems

Reduced turnover rate of topsoil organic carbon in old-growth forests:a case study in subtropical China

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Forest Ecosystems 2021年第4期8卷 778-788页

作者： Xin Xiong Juxiu Liu Guoyi Zhou Qi Deng Huiling zhang Guowei Chu Ze Meng deqiang zhang Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystem South China Botanical GardenChinese Academy of SciencesGuangzhou 510650China Center for Plant Ecology Core Botanical GardensChinese Academy of SciencesGuangzhou 510650China School of Applied Meteorology Nanjing University of Information Science&TechnologyNanjing 210044China

Background:Old-growth forests are irreplaceable with respect to climate change mitigation and have considerable carbon(C)sink potential in ***,the relationship between the soil organic carbon(SOC)turnover rate and forest development is poorly understood,which hinders our ability to assess the C sequestration capacity of soil in old-growth ***:In this study,we evaluated the SOC turnover rate by calculating the isotopic enrichment factor β(defined as the slope of the regression between ^(13)C natural abundance and log-transformed C concentrations)along 0-30 cm soil profiles in three successional forests in subtropical China.A lower β(steeper slope)is associated with a higher turnover *** three forests were a 60-year-old *** forest(PF),a 100-year-old coniferous and broadleaved mixed forest(MF),and a 400-year-old monsoon evergreen broadleaved forest(BF).We also analyzed the soil physicochemical properties in these forests to examine the dynamics of SOC turnover during forest succession and the main ***:The β value for the upper 30-cm soils in the BF was significantly(p<0.05)higher than that in the PF,in addition to the SOC stock,although there were nonsignificant differences between the BF and *** β value was significantly(p<0.05)positively correlated with the soil recalcitrance index,total nitrogen,and available nitrogen contents but was significantly(p<0.01)negatively correlated with soil ***:Our results demonstrate that SOC has lower turnover rates in old-growth forests,accompanied by higher soil chemical recalcitrance,nitrogen status,and lower soil *** finding helps to elucidate the mechanism underlying C sequestration in old-growth forest soils,and emphasizes the important value of old-growth forests among global C sinks.

关键词： Forest succession Old-growth forests Soil organic carbon Turnover rate 13C natural abundance