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Spatial Para Allocation of a Small Watershed Protection Forest System

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Chinese Forestry Science and Technology 2012年第3期11卷 35-36页

作者： chen junhua Gong Gutang Zhu Zhifang Wu Xuexian Mu Changlong Sichuan Academy of Forestry

With the interpreted IKONOS4 satellite images collected in 2005,a 1:10 000 forest map,the data collected in ClassⅡforest survey in 2007,and surface runoff data obtained in the permanent runoff monitoring station,six site factors of slope gradient, slope position,soil thickness,soil thickness of A layer,soil type and soil water content were selected to establish a matter element model suitable to 297 forest ***,the AHP was applied to modify the spatial structure and form the spatial para allocation of the protection forest system. The results showed that:1) the area allocation of different vegetation types was irrational,the area of a mixed coniferous and broad-leafed forest was 124.39 ha,accounting for 14.97%of the forested land,the mixed forest was consisted of two coniferous species accounted for 27.37%of the total forest land,and the pure forest was consisted of one coniferous species accounted for 42.48%.2) After optimization,the area allocation of different vegetation types in the protection forest system ranked as:the mixed coniferous and broad-leafed forest(31.12%)>shrub land(15.5%)>the economic tree crops(12.28%)>the mixed forest consisting of two coniferous species(11.46%)>the pure broad-leafed forest(11.41%)>the pure coniferous forest(9.51%)>grass land(8.70%). Besides,the annual surface runoff could reduce 43 171 mm or 62.15%,annual soil erosion could decrease 465.97 t or 79.66%.3) The following suggestions for spatial para allocation of the small watershed protection forest system were proposed: (1) Reducing pure cypress or pine forest,and increasing alder-cypress,oak-cypress or pine-cypress mixed *** for the current cypress and pine pure forests,alder or oak could be introduced to develop a mixed forest.(2) The canopy closure of pure cypress forest and alder-cypress forests should be maintained within 0.60-0.75,and the canopy closure of oak-cypress,pine-cypress or oak-pine forests should be controlled within 0

关键词： matter element analysis analytic hierarchy process Guansi river watershed protection forest spatial para allocation structural optimization

Lead-free hybrid two-dimensional double perovskite with switchable dielectric phase transition

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Chinese Chemical Letters 2024年第6期35卷 176-179页

作者： Tian Yang Yi Liu Lina Hua Yaoyao chen Wuqian Guo Haojie Xu Xi Zeng Changhao Gao Wenjing Li junhua Luo Zhihua Sun College of Chemistry Fuzhou UniversityFuzhou 350108China State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China

Molecular dielectric switches constitute a type of intelligent materials that are highly coveted for their distinctive advantages of switchable dielectric responses,lightweight,and mechanical ***(2D)hybrid perovskites have demonstrated excellent promise for assembling dielectric switches,in which the dynamic motions of organic moieties afford driving force to trigger switchable dielectric phase ***,we successfully assembled a new lead-free hybrid double perovskite,(CHA)4Cu Bi Br8(1,CHA=cyclohexylammonium),adopting a typical 2D structural motif,which shows dielectric anisotropy and bistable behaviors during the reversible phase transition near T_(c)=378 K(the Curie temperature).That is,its dielectric constants could be switched and tuned between high-dielectric and low-dielectric *** analyses reveal that the ordered-disordered transformation of the organic CHA+moiety and distortion of inorganic framework account for its phase *** result will stimulate further exploration of molecular dielectric switches in this 2D environmentally friendly family.

关键词： Dielectric switch Lead-free Double perovskite Phase transition Symmetry breaking

Stretchable,Transparent,and Ultra-Broadband Terahertz Shielding Thin Films Based on Wrinkled MXene Architectures

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Nano-Micro Letters 2024年第9期16卷 110-122页

作者： Shaodian Yang Zhiqiang Lin Ximiao Wang junhua Huang Rongliang Yang Zibo chen Yi Jia Zhiping Zeng Zhaolong Cao Hongjia Zhu Yougen Hu Enen Li Huanjun chen Tianwu Wang Shaozhi Deng Xuchun Gui State Key Laboratory of Optoelectronic Materials and Technologies School of Electronics and Information TechnologySun Yat-Sen UniversityGuangzhou 510275People’s Republic of China National Key Laboratory of Materials for Integrated Circuits Shenzhen Institute of Advanced Electronic MaterialsShenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen 518055People’s Republic of China Guangdong Province Key Laboratory of Display Material and Technology Guangzhou 510275People’s Republic of China China Academy of Aerospace Science and Innovation Beijing 100176People’s Republic of China School of Materials Science and Engineering Sun Yat-Sen UniversityGuangzhou 510275People’s Republic of China GBA Branch of Aerospace Information Research Institute Chinese Academy of SciencesGuangzhou 510700People’s Republic of China School of Electronic Electrical and Communication EngineeringUniversity of Chinese Academy of SciencesBeijing 100049People’s Republic of China Guangdong Provincial Key Laboratory of Terahertz Quantum Electromagnetics Guangzhou 510700People’s Republic of China

With the increasing demand for terahertz(THz)technology in security inspection,medical imaging,and flexible electronics,there is a significant need for stretchable and transparent THz electromagnetic interference(EMI)shielding *** EMI shielding materials,like opaque metals and carbon-based films,face challenges in achieving both high transparency and high shielding efficiency(SE).Here,a wrinkled structure strategy was proposed to construct ultra-thin,stretchable,and transparent terahertz shielding MXene films,which possesses both isotropous wrinkles(height about 50 nm)and periodic wrinkles(height about 500 nm).Compared to flat film,the wrinkled MXene film(8 nm)demonstrates a remarkable 36.5%increase in SE within the THz *** wrinkled MXene film exhibits an EMI SE of 21.1 dB at the thickness of 100 nm,and an average EMI SE/t of 700 dBμm^(−1)over the 0.1-10 *** calculations suggest that the wrinkled structure enhances the film’s conductivity and surface plasmon resonances,resulting in an improved THz wave ***,the wrinkled structure enhances the MXene films’stretchability and *** bending and stretching(at 30%strain)cycles,the average THz transmittance of the wrinkled film is only 0.5%and 2.4%,*** outstanding performances of the wrinkled MXene film make it a promising THz electromagnetic shielding materials for future smart windows and wearable electronics.

关键词： Terahertz Wrinkle structure Electromagnetic interference shielding MXene

Synthesis of size-controlled and dispersible Sm2Fe17N3 magnetic particles by reduction diffusion process using molten salt

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Journal of Rare Earths 2024年第11期42卷 2105-2111页

作者： junhua Xi Zhi Yang Muhammad Haseeb Yuanyuan chen Xiaofeng Nie Liying Cong Qiong Wu Enfeng Fu Hongguo Zhang Weiqiang Liu Ming Yue Faculty of Materials and Manufacturing Key Laboratory of Advanced Functional MaterialsMinistry of Education of ChinaBeijing University of Technology

The synthesis of size-controlled Sm2Fe17magnetic particles is a prerequisite for the fabrication of highperformance Sm2Fe17N3permanent magnetic ***,Sm2Fe17was synthesized using a costeffective reduction-diffusion *** calcium chloride molten salt was introduced to control the particle size and achieve a single phase of *** effects of reduction-diffusion reaction temperature and the amount of added calcium chloride on the phase constitution and microstructure of the final product of reduction-diffusion were systematically *** an appropriate amount of calcium chloride can effectively inhibit the overgrowth and sintering of the reduced *** employing the strategy of adding 20 wt% of calcium chlorides into the green compacts,we were able to successfully synthesize uniform Sm2Fe17particles that are well-dispersed,with an average size of 2.2 μ***,by combining the optimal reduction-diffusion conditions and the nitriding process,the hard magnetic Sm2Fe17N3material was successfully *** study could be useful for the development of high-performance Sm2Fe17N3magnetic materials utilizing reduction-diffusion technology.

关键词： Molten salt Permanent magnets Rare earths Reduction-diffusion Sm2Fe17N3

Analysis of the Badong Ms5. 1 earthquake source characteristics

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Geodesy and Geodynamics 2014年第4期5卷 16-24页

作者： Wu Haibo chen junhua Shen Xuelin Zhang Lifen Zhao Lingyun Zhang Ke Key Laboratory of Earthquake Geodesy Institute of SeismologyChina Earthquake Administration Earthquake Administration of Hubei Province Earthquake Administration of Shiyan City

The mainshock location of the Badong MsS. 1 earthquake is determined using four location methods ： the simplex method, HYP2000, hyposat, and locSAT; the 350 aftershocks over 3 months are relocated using the double difference location method. The results indicate that aftershocks are distributed as bands along the NEE direction and that the aftershocks 1 month after the mainshock, which are mainly distributed in the west of the mainshock and near the Gaoqiao fault, arc shallow earthquakes within 5 km; the depth of each after- shock after one month is deeper, and two distinct fault planes, for which the geological occurrence is similar to the Gaoqiao and Zhoujiashan-Niukou fault, are shaped. The frequency-spectrum analysis of the recorded wave- form in 12 seismic events indicates that the corner frequency of the mainshock is significantly lower than that of its aftershock and is also lower than a tectonic earthquake of the same magnitude. We considered that this result is related to the constraint of the parameter calibration relationship in the focal spectrum and the lithology change due to water erosion. Combined with the focal mechanism and geological tectonic setting, we conclude that the occurrence of the earthquake is related to the activity of the Daping and Gaoqiao fault and is a reser- voir-induced tectonic seismicity.

关键词： precise location of the mainshock double difference location deep profile corner frequency

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口述历史——图书馆史研究的新途径

大学图书馆学报 2007年第4期25卷 17-20,35页

作者：陈俊华汕头大学图书馆汕头515063

介绍国外利用口述历史从事图书馆史研究的情况,以及图书馆开展口述历史工作的方法,意在为我国图书馆史的研究和史料的收集提供一种新的途径。

关键词：口述历史图书馆史史料

The M_S 4.1 Reservoir-induced Hujiaping Earthquake in the Yangtze Three Gorges Reservoir Region

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Earthquake Research in China 2010年第3期24卷 304-319页

作者： Che Yongtai chen junhua Zhang Lifen Yu Jinzi Liu chenglong Zhang Weihua Institute of Geology China Earthquake Administration Beijing 100029 China Earthquake Administration of Hubei Province Wuhan 430071 China

In this paper,based on the collected data and earthquake field investigation,characteristics of the MS4.1 Hujiaping earthquake of November 22,2008 at Guizhou town in Zigui county,Hubei Province and the geological and hydrogeological conditions and seismicity background of the area are analyzed,and the earthquake disaster is presented. Some scientific issues relating to earthquake precursors and the cause of the earthquake is discussed. The authors consider that the earthquake is a tectonic type reservoir-induced earthquake,occurring along the Xiannvshan fault under the joint action of reservoir water loading and water infiltration,and that there were certain suspected anomalies appearing in the gravity field before the earthquake. The cause of the earthquake may also be related to the effect of the Wenchuan earthquake on the local stress field.

关键词： Yangtze Three Gorges Xiannvshan fault Reservoir-induced earthquake TheMs4. 1 Hujiaping earthquake

C_f/C复合材料铜基活性钎料真空钎焊接头的组织与性能

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热加工工艺 2010年第22期39卷 94-96页

作者：陈俊华山东劳动职业技术学院山东济南250061

用铜基活性钎料对Cf/C复合材料进行真空钎焊,并对接头的微观组织、形成机理和接头强度进行研究。结果表明,使用铜基活性钎料可实现Cf/C复合材料的连接,且在实验温度范围内,钎料成分对接头强度具有重要影响。室温下焊接接头的最高剪切强... 详细信息

用铜基活性钎料对Cf/C复合材料进行真空钎焊,并对接头的微观组织、形成机理和接头强度进行研究。结果表明,使用铜基活性钎料可实现Cf/C复合材料的连接,且在实验温度范围内,钎料成分对接头强度具有重要影响。室温下焊接接头的最高剪切强度达21 MPa。

关键词： Cf/C复合材料铜基活性钎料真空钎焊剪切强度

“创造史料”的图书馆——口述历史在地方文献工作中的应用

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图书情报工作 2007年第5期51卷 130-133页

作者：陈俊华汕头大学图书馆汕头515063

口述历史具有史料性质,深受国外图书馆的重视。国内地方文献工作若开辟此领域,对其发展将有较大的拓展。这既是对即将逝去的口头文化遗产的抢救,也是图书馆补充馆藏、形成特色的方式之一。口述历史资源建设在图书馆有三个执行层次,其中... 详细信息

口述历史具有史料性质,深受国外图书馆的重视。国内地方文献工作若开辟此领域,对其发展将有较大的拓展。这既是对即将逝去的口头文化遗产的抢救,也是图书馆补充馆藏、形成特色的方式之一。口述历史资源建设在图书馆有三个执行层次,其中第三层最具挑战性,即建设口述历史项目创造新的史料,须经过学习、计划、宣传、培训、准备、采访、整理与服务等步骤。

关键词：口述历史地方文献史料口头文化遗产