The Juancheng chondrite──A new meteorite falling recently in China

The Juancheng chondrite, a new meteorite falling recently in Juancheng County, Shandong Province, China, is classified as an H5 (S2) chondrite based on the compositions of olivine (Fa= 19.2, σ Fa=0.46) and low-Ca pyroxene (Fs=16.9, σ Fa=0.4). The plagioclase in the Juancheng chondrite is rich in CaO, indicating a relatively high metamorphic temperature the parent body underwent.     

莆田市凤眼莲影响状况及其防治对策

文章通过对莆田市的凤眼莲分布及影响情况进行调查．阐述它所带来的各方面危害，并分析危害产生的成因．结合莆田市的实际情况提出了综合生态治理的对策，并建议结合上海市黄浦江凤眼莲综合管理模式，对我市的凤眼莲展开有效的治理．     

传统法生产氧化锆除硅工艺的研究

对传统的烧碱-盐酸法生产氧化锆中一次水漂洗除硅,二次盐酸提取除硅及工艺过程中的三次除硅进行了研究,提出了水处理法二次除硅新工艺,为硅胶的分离及生产高纯度氧化锆提供了较满意的工艺方法。     

山地杉木人工林择伐环境效益价值动态变化

以33a生杉木(Cunninghamia lanceolata(Lamb.)Hook.)人工纯林为研究对象,研究择伐强度对森林环境效益的影响.设置弱度(12.5%)、中度(22.9%)、强度(49.3%)和极强度(62.7%)4种不同择伐强度,跟踪调查试验样地5a和8a后土壤及凋落物持水、保肥及林分固碳释氧的价值变化,分析不同择伐强度对生态环境效益的影响.结果表明:随着择伐强度的增大,生态环境效益总价值呈先增大后减小的变化趋势;弱度和中度择伐5a和8 a后,可产生环境收益463.5~804.2元/hm2;强度择伐5 a后,导致环境成本23.7元/hm2,但8 a后可产生环境收益747.4元/hm2;极强度择伐5 a和8 a后,导致环境成本488.6和48.1元/hm2.因此,杉木人工林弱度、中度和强度择伐,能较好地促进其发挥涵养水源、保肥和固碳释氧3方面的生态服务功能,建议类似林分择伐强度不超过强度择伐.     

Noble gas and cosmic-ray exposure age of Juancheng chondrite

The analytical results of noble gase in recently fallen Juancheng chondrite indicate that cosmic-ray ages of cosmogenic nuclei of³He,²¹Ne and³⁸Ar are 5.1, 5.0 and 5.8 Ma, respectively, averaging 5.3 Ma. The gas retention ages radiogenic nuclei of⁴He and⁴⁰Ar are 3 200 and 4 200 Ma, respectively. The average cosmic-ray age shows that it has occurred at breakup of the meteoroid from its parent body by impact before 5.3 Ma.     

Bipartite Consensus of Linear Multi-Agent Systems by Distributed Event-Triggered Control

For multi-agent systems with competitive and collaborative relationships, signed graph can more intuitively express the characteristics of their interactive networks. In this paper, the bipartite consensus is investigated for multi-agent systems with structurally balanced signed graph. In order to reduce actuation burden in dynamical network environment, the event-triggering strategy is applied to bipartite consensus protocol for the multi-agent systems. The triggered condition for each agent is designed by using its own information and transmitted information of its neighbors at sampling instant and make the number of triggers of the whole systems be reduced. Based on the distributed eventtriggered control, some sufficient conditions are derived to guarantee the leaderless and leader-following bipartite consensus. Finally, some numerical examples are shown to demonstrate the effectiveness of the theoretical results.     

Scaled Bipartite Consensus Controller Design for Second-Order Multi-Agent Systems with Mixed Time-Delays

Journal of Systems Science and Complexity - The scaled bipartite consensus of second-order multi-agent systems is investigated in this paper. The internal delay and distributed delay are also...