Results 1 to 10 of about 254 (44)
Abstract Over the past decade, China's central and municipal governments have consistently supported the development of social credit systems (SCSs). While research has highlighted the Chinese public's high approval and backing of SCSs, their engagement with these digital projects has not been fully explored. Based on 44 semi‐structured interviews, our
Haili Li, Genia Kostka
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利用风况资料和Google Earth卫星影像,分析研究区域的风况特征及沙丘运移特征,并研究沙丘年运移速度、方向及其规律,对防沙治沙手段的提高具有重要意义。结果表明:(1)研究区年平均风速为1.535~1.768 m/s,起沙风平均风速最高值出现在5,6月,全年起沙风平均风速的最低值出现在1月。(2)起沙风和输沙势主要分布在WSW、W、WNW和NW方位。(3)输沙势为0~26 VU,属于低风能环境;风向变率为0.5~0.9,属于中风向变率,钝双峰风况。(4)研究区沙丘年平均移动速度为12.26 m/a ...
赛亚热 +5 more
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为分析不同土壤类型的性质、界定易风蚀性土壤类型并探索其特征,选取豫东北黄泛区为研究区域,采用野外取样、室内试验分析结合的方法测定土壤颗粒粒径、可蚀性因子K值等指标,界定区域易风蚀性土壤类型,并分析其空间分布特征。结果表明:(1)从土类看,豫东北黄泛区4种土类,以潮土为主,占区域面积的65.57%;从亚类看,共11种土壤亚类,以小两合土、沙土为主,占区域面积的59.76%。(2)土壤颗粒粒径组成上,沙土、草甸风沙土、盐化潮土、淤土等类型以砂粒为主;其余类型以粉粒为主。沙土、草甸风沙土、灌淤潮土 ...
高睿瑜 +7 more
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Assessing the Corn Belt as an anthropogenic barrier to migrating landbirds in the United States
Abstract Migrating landbirds adjust their flight and stopover behaviors to efficiently cross inhospitable geographies, such as the Gulf of Mexico and the Sahara Desert. In addition to these natural barriers, birds may increasingly encounter anthropogenic barriers created by large‐scale changes in land use. One such barrier could be the Corn Belt in the
Fengyi Guo +7 more
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On the normative roles of biodiversity and naturalness in conservation
Abstract Nature is an opaque concept. Consequently, the term biodiversity conservation has replaced nature conservation in most conservation contexts. We review the conceptual indeterminacies that plague the terms nature and natural but then show that comparable difficulties plague biodiversity.
David Saltz, Shlomo Cohen
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No Limits: The Biden Administration's Support for Israel's War on Gaza
ABSTRACT The war in Gaza that Israel launched in response to the Hamas‐led attack in southern Israel on October 7, 2023, has been the longest and deadliest war in the history of the Israeli‐Palestinian conflict and one of the most lethal and destructive in recent history.
Dov Waxman, Jeremy Pressman
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风沙区由于林带的缺少,雨养耕地风蚀现象严重,就地起沙,形成了风蚀地以及风积地在短距离内交错分布的特点。通过对风沙区雨养耕地土壤水养状况的定位研究得出:没有防护林带保护的雨养耕地有3种类型,即风蚀地、积沙地、过渡地段。沿主害风方向,上风地段为风蚀沙地,下风地段为风积沙地。风蚀沙地水分状况最好,风积沙地最差;表层土壤(0~20cm)养分状况比下层(20~60cm)差,风积沙地肥力最低,过渡地段最好。沙区雨养耕地特点明显,一年中土壤含水率变幅比降水量小得多,水养同步作物生产力水平高;农作物产量与土壤中全N ...
吴祥云 张黎 卢慧
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对青藏铁路K1533处高立式沙障和石方格沙障防风固沙的效益进行了研究,结果表明:高立式沙障可有效地降低防护区的风速,风速降幅范围在第1沙障后为14.63%~86.15%,第2沙障后为41.93%~97.91%,第3沙障后为22.80%~87.40%;同时降低了防护区的侵蚀量,高立式沙障后的侵蚀量和对照区相比,第1沙障后的侵蚀量仅占对照区的21.75%,第2,3沙障后的侵蚀量和对照区相比,其值缩小了数十倍到数百倍。石方格区的侵蚀量减幅更大,和对照区相比,相同高度的侵蚀量缩小了数十倍到数百倍甚至数千倍 ...
刘世海, 冯玲正, 许兆义
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仿真固沙灌木是一种由抗老化的高分子化合物聚合而成并具有与油蒿、沙蒿等沙生灌木相似外部形状的新型防风固沙材料。在风洞内对不同疏透度(β)的仿真固沙灌木,在7,9,12,15m/s的实验风速下进行模拟研究,测定其防风与积沙效应,探讨输沙量与风速和疏透度之间的关系。结果表明:仿真固沙灌木在不同风速条件下,整个风速流场过程可分为灌木前部、灌木内部、灌木后部3个区域,形成6个减速区和4个加速区,共10个新能区。其中,障前H、0.5H区域和障后0.5H~3H区域为主要的风速削减区 ...
孙涛 +6 more
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选取冀北坝上地区防风固沙林为研究对象,通过观测风速、地表粗糙度、临界起沙风速、输沙量、风沙流结构等指标,对比分析3种人工灌木林地(沙棘林地、柠条林地、沙柳林地)防风蚀效果。结果表明:人工植被能够增加地表粗糙度,改变近地表风场和风沙流结构,降低风速,减少输沙量,有效防治土壤风蚀。不同人工灌木林地防风蚀效果存在较大差异。从主要观测指标来看,粗糙度和临界起沙风速为柠条林地 > 沙棘林地 > 沙柳林地;输沙量为柠条林地 < 沙棘林地 < 沙柳林地;防风效应为沙棘林地 > 沙柳林地 > 柠条林地 ...
杨越 +5 more
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