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| 1 | Evaluation and scenario simulation for forest ecological security in China显示文摘Continuously growing populations and rapid economic development have led to the excessive use of forest resources,and the forest ecosystem is threatened.In response,forest ecological security(FES)has attracted attention.In this study,an integrated dynamic simulation model was constructed using the system dynamic method,and it was used to evaluate the FES in China from 1999 to 2014.A scenario analysis was then used to evaluate the changes in the FES under five forestry policy scenarios for the 2015–2050 period,including the baseline,afforestation policy,harvesting policies,management policy,investment policy,and a policy mix.The results showed that the evaluation values of the FES increased during the period from 1999 to 2002,the period from 2004 to 2010 and the year 2014,and they decreased in 2003 and during the period from 2011 to 2013.During the 2015–2050 simulation period,the FES improved continuously.In particular,China would enter a new stage when the economic systems,social systems and ecosystems were in harmony after 2040.To improve the FES and the current status of the FES,a scenario analysis showed the most suitable scenario to be Scenario 5 from 2015 to 2020 and Scenario 2 from 2021 to 2050.To relieve pressure,the most suitable scenario would be Scenario 5 from 2015 to 2040 and from 2046 to 2050,and the most suitable scenario would be Scenario 4 for 2041–2045.A policy mix(Scenario 5)would be most efficient under current conditions,while the effects of all the benefits of the forestry policies would weaken over the long term.The integrated method can be regarded as a decision support tool to help policy makers understand FES and promulgate a reasonable forestry policy. | Qin Zhang Guangyu Wang Feng Mi Xuanchang Zhang Lianzhen Xu Yufang Zhang Xiaoli Jiang | 2019 | Journal of Forestry Research2019，30，5： | 5 |
| 2 | Design and optimization of DBR in 980 nm bottom-emitting VCSEL显示文摘According to the theory of DBR,with the P-type DBR as an example,the electrical characteristics and optical reflection of the DBR are analyzed by studying the energy band structure with various graded region widths and doping densities. The width and doping density of graded region are decided through a comparative study. The P-type DBR of 980 nm VCSELs is designed with Al0.9Ga0.1As and Al0.1Ga0.9As selected as the high and low refractive index material for the DBR. The 980 nm bottom VCSELs,which consists of 30 pairs P-type DBR and 28 pairs N-type DBR,are then fabricated. In P-type DBR,the width of graded region is 0.02 μm and the uniformity doping concentration is 2.5×1018cm-3. Its reflectivity is 99.9%. In N-type DBR,the width of graded region is also 0.02 μm and the uniformity doping concen-tration is 2×1018cm-3. Its reflectivity is 99.3%. The I-V curve shows that the series resistance of the device is about 0.05 Ω. According to the theory of DBR,with the P-type DBR as an example,the electri-cal characteristics and optical reflection of the DBR are analyzed by studying the energy band structure with various graded region widths and doping densities. The width and doping density of graded re-gion are decided through a comparative study. The P-type DBR of 980 nm VCSELs is designed,with Al0.9Ga0.1As and Al0.1Ga0.9As selected as the high and low refractive index material for the DBR. The 980 nm bottom VCSELs,which consist of 30 pairs P-type DBR and 28 pairs N-type DBR,are then fabri-cated. In P-type DBR,the width of graded region is 0.02 μm and the uniformity doping concentration is 2.5×1018cm-3. Its reflectivity is 99.9%. In N-type DBR,the width of graded region is also 0.02 μm and the uniformity doping concentration is 2×1018cm-3. Its reflectivity is 99.3%. The I-V curve shows that the series resistance of the device is about 0.05 Ω. | LI Te NING YongQiang HAO ErJuan CUI JinJiang ZHANG Yan LIU GuangYu QIN Li LIU Yun WANG LiJun CUI DaFu XU ZuYan | 2009 | Science in China(Series F)2009，52，7： | 4 |
| 3 | Carbonized wood with ordered channels decorated by NiCo_(2)O_(4) for lightweight and high-performance microwave absorber显示文摘Wood-derived carbon has a 3D porous framework composed of through channels along the growth direction,which is a suitable matrix for preparing electromagnetic wave(EMW)absorbing materials with low cost,light weight,and environmental friendliness.Herein,the carbonized wood decorated by short cone-like NiCo_(2)O_(4)(NiCo_(2)O_(4)@CW)with highly ordered straight-channel architecture was successfully manufactured through a facile calcination procedure.The horizontal arrangement of the through channels of NiCo_(2)O_(4)@CW(H-NiCo_(2)O_(4)@CW)exhibits a strong reflection loss value of-64.0 dB at 10.72 GHz with a thickness of 3.62 mm and a low filling ratio of 26 wt%(with the density of 0.98 g-cnf3),and the effective absorption bandwidth(EAB)is 8.08 GHz(9.92-18.0 GHz)at the thickness of 3.2 mm.The excellent microwave absorption(MA)property was ascribed to the ordered-channel structure with abundant interfaces and defects from NiCo_(2)O_(4)@CW,which could promote the interfacial polarization and dipole polarization.What is more,this advantageous structure increased the multiple reflections and scattering.Finite element analysis(FEA)simulation is carried out to detect the interaction between the prepared material and EMW when the ordered channels are arranged in different directions.This research provides a low-cost,sustainable,and environmentally friendly strategy for using carbonized wood to fabricate microwave absorbers with strong attenuation capabilities and light weight. | Guangyu QIN Xiaoxiao HUANG Xu YAN Yunfei HE Yuhao LIU Long XIA Bo ZHONG | 2022 | Journal of Advanced Ceramics2022，11，1： | 2 |
| 4 | Model division multiple access for semantic communications显示文摘In a multi-user system,system resources should be allocated to different users.In traditional communication systems,system resources generally include time,frequency,space,and power,so multiple access technologies such as time division multiple access(TDMA),frequency division multiple access(FDMA),space division multiple access(SDMA),code division multiple access(CDMA),and non-orthogonal multiple access(NOMA)are widely used.In semantic communication,which is considered a new paradigm of the next-generation communication system,we extract high-dimensional features from signal sources in a model-based artificial intelligence approach from a semantic perspective and construct a model information space for signal sources and channel features.From the high-dimensional semantic space,we excavate the shared and personalized information of semantic information and propose a novel multiple access technology,named model division multiple access(MDMA),which is based on the resource of the semantic domain.From the perspective of information theory,we prove that MDMA can attain more performance gains than traditional multiple access technologies.Simulation results show that MDMA saves more bandwidth resources than traditional multiple access technologies,and that MDMA has at least a 5-dB advantage over NOMA in the additive white Gaussian noise(AWGN)channel under the low signal-to-noise(SNR)condition. | Ping ZHANG Xiaodong XU Chen DONG Kai NIU Haotai LIANG Zijian LIANG Xiaoqi QIN Mengying SUN Hao CHEN Nan MA Wenjun XU Guangyu WANG Xiaofeng TAO | 2023 | Frontiers of Information Technology & Electronic Engineering2023，24，6： | 2 |
| 5 | Ethnic specificity of variants of the ESR1, HK3, BRSK1 genes and the 8q22.3 locus: No association with premature ovarian failure (POF) in Serbian women显示文摘 | Yingying Qin Svetlana Vujovic Guangyu Li Jin Li Raymond Dalgleish Joe Leigh Simpson Maja Ivanisevic Miomira Ivovic Milina Tancic Farook Al-Azzawi Zi-Jiang Chen | 2014 | Maturitas2014，，1： | 1 |
| 6 | Effect of the precipitation state on high temperature tensile and creep behaviors of Mg-15Gd alloy显示文摘Due to the effective precipitation strengthening effect of the β phase, Mg-Gd alloys exhibit excellent room temperature mechanical behaviors. However, when served at high temperatures, the metastable β phase will transform to other phases, resulting in severe performance degradation. In this study, we investigated the effect of precipitation state achieved by different heat treatments on high temperature tensile and creep behaviors of the Mg-15Gd alloy by comparing the properties of the as-cast, solid-solutioned(T4) and peak-aged(T6) alloys. The results showed that the tensile mechanical properties of the T6 alloy were always highest from room temperature to 300 ℃, in spite of an abnormal strength increase with temperature existed in the T4 alloy. For tensile creep properties, the T6 alloy exhibited the lowest steady creep rate below 235 ℃ while the T4 alloy possessed the best properties above 260 ℃. Microstructure characterization revealed that the transition was caused by the stress-promoted precipitation of β phase in the T4 alloy and rapid phase transformation in the T6 alloy at high temperatures. At 260 ℃, the calculated stress exponent n was 3.1 and 2.8 for the T4 and T6 alloys, respectively, suggesting the creep deformation mechanism was dislocation slip, which was further confirmed by the microstructure after creeping. Our findings can provide new insights into the heat treatment process of Mg-Gd alloys served at high temperatures. | Shuxia Ouyang Guangyu Yang He Qin Chunhui Wang Shifeng Luo Wanqi Jie | 2022 | Journal of Magnesium and Alloys2022，10，12： | 1 |
| 7 | Effect of coir geotextile and geocell on ephemeral gully erosion in the Mollisol region of Northeast China显示文摘The unique geomorphological features and farming methods in the Mollisol region of Northeast China increase water catchment flow and aggravate the erosion of ephemeral gully(EG).Vegetation suffers from rain erosion and damage during the growth stage,which brings serious problems to the restoration of grass in the early stage.Therefore,effects of coir geotextile and geocell on EG erosion under four confluence intensities were researched in this study.Results of the simulated water discharge erosion test showed that when the confluence strength was less than 30 L/min,geocell and coir geotextile had a good effect on controlling EG erosion,and sediment yield of geocell and coir geotextile was reduced by 25.95%–37.82%and 73.73%–88.96%,respectively.However,when confluence intensity increased to 40 L/min,protective effect of coir geotextile decreased,and sediment yield rate increased sharply by 189.03%.When confluence intensity increased to 50 L/min,the protective effect of coir geotextile was lost.On the other hand,geocell showed that the greater the flow rate,the better the protective effect.In addition,with the increase in confluence intensity,erosion pattern of coir geotextile developed from sheet erosion to intermittent fall and then to completion of main rill,and the protective effect was gradually weakened.In contrast,the protective effect of EG under geocell was gradually enhanced from the continuous rill to the intermittent rill and finally to the intermittent fall.This study shows that coir geotextile and geocell can prevent EG erosion,and the effect of geocell is better than that of coir geotextile on the surface of EG. | QIN Xijin SUN Yiqiu ZHANG Yan GUAN Yinghui WU Hailong WANG Xinyu WANG Guangyu | 2024 | Journal of Arid Land2024，16，4： | 0 |
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