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CO_(2)emission and source partitioning from carbonate and non-carbonate soils during incubation

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Pedosphere 2022年第3期32卷 452-462页

作者： Yi ZHAO roland bol Zhaoan SUN Yuping ZHUGE Xiaoxia SHI Wenliang WU Fanqiao MENG Beijing Key Laboratory of Biodiversity and Organic Farming College of Resources and Environmental SciencesChina Agricultural UniversityBeijing 100193(China) Institute of Bio-and Geosciences Agrosphere(IBG-3)Forschungszentrum Jülich GmbHJülich 52425(Germany) Key Laboratory of Biology and Molecular Biology in University of Shandong College of Biological and Agricultural EngineeringWeifang UniversityWeifang 261061(China) National Engineering Laboratory for Efficient Utilization of Soil and Fertilizer Resources College of Resources and EnvironmentShandong Agricultural UniversityTai'an 271018(China) SinoCarbon Innovation&Investment Jiangsu Co. Ltd.(SCII)Nanjing 210046(China)

The accurate quantification and source partitioning of CO_(2)emitted from carbonate(i.e.,Haplustalf)and non-carbonate(i.e.,Hapludult)soils are critically important for understanding terrestrial carbon(C)*** two main methods to capture CO_(2)released from soils are the alkali trap method and the direct gas sampling method.A 25-d laboratory incubation experiment was conducted to compare the efficacies of these two methods to analyze CO_(2)emissions from the non-carbonate and carbonate-rich *** isotopic fraction was introduced into the calculations to determine the impacts on partitioning of the sources of CO_(2)into soil organic carbon(SOC)and soil inorganic carbon(SIC)and into C3 and/or C4 plant-derived *** results indicated that CO_(2)emissions from the non-carbonate soil measured using the alkali trap and gas sampling methods were not significantly *** the carbonate-rich soil,the CO_(2)emission measured using the alkali trap method was significantly higher than that measured using the gas sampling method from the 14 th day of incubation *** SOC and SIC each accounted for about 50%of total soil C in the carbonate-rich soil,SOC decomposition contributed 57%–72%of the total CO_(2)*** both non-carbonate and carbonate-rich soils,the SOC derived from C4 plants decomposed faster than that originated from C3 *** propose that for carbonate soil,CO_(2)emission may be overestimated using the alkali trap method because of decreasing CO_(2)pressure within the incubation jar,but underestimated using the direct gas sampling *** gas sampling interval and ambient air may be important sources of error,and steps should be taken to mitigate errors related to these factors in soil incubation and CO_(2)quantification studies.

关键词： alkali trap C3/C4 plant inorganic carbon stock isotope fractionation organic carbon stock

Spatial-temporal variations and driving factors of soil organic carbon in forest ecosystems of Northeast China

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Forest Ecosystems 2023年第2期10卷 141-152页

作者： Shuai Wang bol roland Kabindra Adhikari Qianlai Zhuang Xinxin Jin Chunlan Han Fengkui Qian College of Land and Environment Shenyang Agricultural UniversityShenyang110866China Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchCASBeijing100101China Institute of Bio-and Geosciences Agrosphere(IBG-3)Forschungszentrum Jülich GmbHWilhelm-Johnen-Straße52428JülichGermany School of Natural Sciences Environment Centre WalesBangor UniversityBangorLL572UWUK USDA-ARS GrasslandSoil and Water Research LaboratoryTempleTX76502USA Department of Earth Atmosphericand Planetary SciencesPurdue UniversityWest LafayetteIN47907USA

Forest soil carbon is a major carbon pool of terrestrial ecosystems,and accurate estimation of soil organic carbon(SOC)stocks in forest ecosystems is rather *** study compared the prediction performance of three empirical model approaches namely,regression kriging(RK),multiple stepwise regression(MSR),random forest(RF),and boosted regression trees(BRT)to predict SOC stocks in Northeast China for 1990 and ***,the spatial variation of SOC stocks and the main controlling environmental factors during the past 25 years were identified.A total of 82(in 1990)and 157(in 2015)topsoil(0–20 cm)samples with 12 environmental factors(soil property,climate,topography and biology)were selected for model *** selected80%of the soil sample data were used to train the models and the other 20%data for model verification using mean absolute error,root mean square error,coefficient of determination and Lin's consistency correlation coefficient *** found BRT model as the best prediction model and it could explain 67%and 60%spatial variation of SOC stocks,in 1990,and 2015,*** maps of all models in both periods showed similar spatial distribution characteristics,with the lower SOC in northeast and higher SOC in *** annual temperature and elevation were the key environmental factors influencing the spatial variation of SOC stock in both *** stocks were mainly stored under Cambosols,Gleyosols and Isohumosols,accounting for 95.6%(1990)and 95.9%(2015).Overall,SOC stocks increased by 471 Tg C during the past 25 *** study found that the BRT model employing common environmental factors was the most robust method for forest topsoil SOC stocks *** spatial resolution of BRT model enabled us to pinpoint in which areas of Northeast China that new forest tree planting would be most effective for enhancing forest C ***,our approach is likely to be useful in forestry management and ecologic

关键词： Soil organic carbon stocks Forest ecosystem Spatial-temporal variation Carbon sink Digital soil mapping

Soil Organic Matter Composition in Coastal and Continental Date Palm Systems: Insights from Tunisian Oases

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Pedosphere 2019年第4期29卷 444-456页

作者： Rawan K. MLIH Martina I. GOCKE roland bol Anne E. BERNS Irabella FUHRMANN Nadhem BRAHIM Institute of Crop Science and Resource Conservation University of Bonn Bonn 53115 (Germany) Agrosphere Institute (IBG-3) Forschungszentrum Julich GmbH Julich 52428 (Germany) Department of Geology University of Tunis El Manar Tunis 2092 (Tunisia)

In Tunisia, the coastal Chenini oasis is characterized by a lush vegetation cover, whereas more inland continental oases(e.g., the Guettaya oasis) have a very scarce vegetation cover. For sustaining date palm production in these areas, organic fertilizers are applied,either spread on the soil surface(in Chenini) or buried under a sand layer(in Guettaya). We examined at a molecular level how these management techniques affect soil organic matter composition in oasis systems. A dominance of fresh plant input for Guettaya was indicated by solid-state 13C nuclear magnetic resonance spectroscopy signals, which was most pronounced in the uppermost soil close to palms. Evidence for more degraded organic matter was found in deeper soil near the palms, as well as in the soil distant from the palms. Amino sugar contents were low in the uppermost Guettaya soil near the palms. The overall microbial amino sugar residue contents were similar in range as those found in other dryland environments. With increasing distance from trees, the amino sugar contents declined in Guettaya, where the palms grow on bare soil, but this was not the case for Chenini, which has multi-layer vegetation cover under palms. In agreement with the results from previous dryland studies, the soil microbial community in both oasis systems was dominated by fungi in topsoil, and a shift toward bacteria-derived residues in subsurface soil. This might be due to higher variability of temperature and moisture in topsoil and/or lower degradability of fungal remains;however, further research is required to confirm this hypothesis.

关键词： amino sugar dryland microbial community soil organic carbon solid-state NMR subsoil amelioration total nitrogen

Investigation on Superplasticity in SiC_p/2024 Cold Rolling Sheet after Heat Treatment

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Journal of Materials Science & Technology 2003年第4期19卷 382-384页

作者： bolüXIAO ZongyiMA JingBI InstituteofMetalResearch ChineseAcademyofSciencesShenyang110016China DepartmentofMetallurgicalEngineering UniversityofMissouriRollaRollaMO65401USA

High strain rate superplastic deformation behavior of powder metallurgy (PM) processed 17 vol. pet SiCp/2024 Al composite sheet after heat treatment was investigated over a range of temperature from 753 to 833 K. At 813 K, a maximum elongation of 259% was discovered at a strain rate of 10-1 s-1. The activation energy was closed to that for lattice diffusion of Al and increased at temperature upon incipient melting temperature. The mechanism of superplastic deformation for present composites was attributed to lattice diffusion controlled grain boundary sliding.

关键词： Superplasticity Powder metallurgy Metai matrix composites

Effect of heat treatment on the microstructure,mechanical properties and fracture behaviors of ultra-high-strength SiC/Al-Zn-Mg-Cu composites

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International Journal of Minerals,Metallurgy and Materials 2024年第10期31卷 2233-2243页

作者： Guonan Ma Shize Zhu Dong Wang Peng Xue bolüXiao Zongyi Ma Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Centre of Excellence for Advanced Materials Dongguan 523808China

A high-zinc composite,12vol%SiC/Al-13.3 Zn-3.27 Mg-1.07Cu(wt%),with an ultra-high-strength of 781 MPa was success-fully fabricated through a powder metallurgy method,followed by an extrusion *** effects of solid-solution and aging heat treat-ments on the microstructure and mechanical properties of the composite were extensively *** with a single-stage sol-id-solution treatment,a two-stage solid-solution treatment(470℃/1 h+480℃/1 h)exhibited a more effective solid-solution strengthen-ing owing to the higher degree of solid-solution and a more uniform *** to the aging hardness curves of the com-posite,the optimized aging parameter(100℃/22 h)was *** the aging temperature and time resulted in finer and more uniform nanoscale precipitates but only yielded a marginal increase in tensile *** fractography analysis revealed that intergranu-lar cracking and interface debonding were the main fracture mechanisms in the ultra-high-strength SiC/Al-Zn-Mg-Cu *** regions,such as the SiC/Al interface containing numerous compounds and the precipitate-free zones at the high-angle grain boundaries,were identified as significant factors limiting the strength enhancement of the *** compounds,including MgO,MgZn2,and Cu5Zn8,reduced the interfacial bonding strength,leading to interfacial debonding.

关键词： metal matrix composites heat treatment interfacial reaction mechanical properties fracture mechanism

High Responsivity and Ultra-Low Detection Limits in Nonlinear a-Si:H p-i-n Photodiodes Enabled by Photogating

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Photonic Sensors 2023年第4期13卷 27-38页

作者： Andreas BABLICH Maurice MÜLLER Rainer BORNEMANN Andreas NACHTIGAL Peter HARING bolÍVAR Institute of Graphene-Based Nanotechnology University of SiegenHölderlinstr.357076 SiegenGermany Institute of High Frequency and Quantum Electronics University of SiegenHölderlinstr.357076 SiegenGermany

Photodetectors operating at the wavelength in the visible spectrum are key components in high-performance optoelectronic *** this work,massive nonlinearities in amorphous silicon p-i-n photodiodes enabled by the photogating are presented,resulting in responsivities up to 744 mA/W at blue *** detectors exhibit significant responsivity gains at optical modulation frequencies exceeding MHz and a more than 60-fold enhanced spectral response compared to the non-gated *** detection limits down to 10.4 nW/mm^(2) and mean signal-to-noise ratio enhancements of 8.5dB are demonstrated by illuminating the sensor with an additional 6.6μW/mm^(2) red ***-optical simulations verify photocarrier modulation due to defect-induced field screening to be the origin of such high responsivity *** experimental results validate the theory and enable the development of commercially viable and complementary metal oxide semiconductor(CMOS)compatible high responsivity photodetectors operating in the visible range for low-light level imaging and detection.

关键词： Photogating amorphous silicon a-Si:H nonlinearity photodetector responsivity gain

The Current Status and Future Prospects of Forest Certification in Myanmar

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The Current Status and Future Prospects of Forest Certificat...

作者： Ei Thandar bol 北京林业大学

学位级别：硕士

Myanmar had been practicing Sustainable Forest Management since1856. Although Myanmar had a long history in Forest Management, Myanmar does not have internationally recognized certification standard, such as FSC or PEFC. To get Forest Certification is the goal of our Sustainable Forest Management. Nowadays Myanmar faces preparation for potential negotiations with the European Union, ASEAN’s agreement and international organizations in the field of sustainable forest management. The main purpose of this study is that to explore about Forest Certification in Myanmar. In this thesis the researcher tries to analyze the level of Myanmar Forest Certification progress, to identify the key elements for the development and implementation of timber legality in Myanmar by using qualitative research methodology. Myanmar has started Timber Certification process in1988and achieved to some extent. However, it needs to go a long way especially to comply with the standards （C＆I） for the forest management certification. The analysis will also deal with the real situation of forest certification in Myanmar and also try to base on the COCs of timber legality tracking system, market functionality, status of C＆I, policy and remedial measure. It is concluded and argued in this thesis it evident that Myanmar is in a pioneer stage of forest certification and moved the topic on the national level. According to the management systems an adaptation of biodiversity conservation practices, RIL, Code of Forest Harvesting, Community Forest Instructions and Timber Legality Assurance System are some major achievements.

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Wear behavior of the raw and pre-smashed carbon nanotubes reinforced 6061Al composites fabricated by powder metallurgy

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Science China(Technological Sciences) 2022年第5期65卷 1149-1159页

作者： LI XiaoNan LIU ZhenYu ZAN YuNing XIAO bolü NI DingRui WANG QuanZhao WANG Dong MA ZongYi Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang110016China

The raw and pre-smashed(PS)carbon nanotube(CNT)reinforced 6061Al composites(CNT/6061Al)with different CNT contents were respectively fabricated by powder metallurgy *** was found that reducing the CNT cluster size by presmashing processing could sharply reduce the friction coefficient,and significantly improve the density,hardness,and wear resistance of the CNT/6061Al *** the raw-CNT/6061Al composites,the wear rate increased approximately linear trend while the CNT content was over 1 wt.%.The plastic deformation,deep grooves,and serious delamination were presented on the wear *** wear process was gradually transformed from Al-copper base counterpart wear into Al-Al wear for the higher adhesion-binding energy between aluminum and copper base *** for the PS-CNT/6061Al composites,the wear rate gradually decreased as the CNT content increased from 0 to 2 wt.%.This was mainly because the generation of the thinner mechanically mixed layer(MML)and the PS-CNT prevented the direct contact between specimen and copper base counterpart,which effectively inhibited the adhesive *** excessive PS-CNTaddition(~3 wt.%)would weaken the bonding between CNT and 6061Al,and thus the wear resistance of the composite was reduced apparently.

关键词： wear carbon nanotube aluminum matrix composites clustering

Mechanical properties of(B_(4)C+Al_(2)O_(3))/Al neutron absorbing materials with various microstructures constructed by hot forging,rolling and extrusion

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Science China(Technological Sciences) 2022年第5期65卷 1206-1209页

作者： ZAN YuNing LI XinNan ZHOU Cong LIU ZhenYu WANG QuanZhao XIAO bolü MA ZongYi Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang110016China Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang110016China Nuclear Equipment Division Beijing Institute of Nuclear EngineeringChina Nuclear Power Engineering Co.Ltd.Beijing100840China

Neutron absorbing materials(NAMs)are necessary in the nuclear industry for the storage and transportation of spent *** all the NAMs,B_(4)C/Al composites are widely used because of the specific neutron absorption capacity[1–4].Compared with traditional low-strength functional NAMs such as B_(4)C/1100Al and B_(4)C/6061Al,NAMs with enough high-temperature(350℃)strength are competent for further structural usage and exhibit huge advantages in the dry storage of spent fuel because of heat transfer ability and weight reduction[5].

关键词： absorbing strength enough