Results 11 to 20 of about 182,646 (104)
A half-discrete Hilbert-type inequality with a non-homogeneous kernel(一个半离散非齐次核的Hilbert型不等式)
Zhejiang Daxue xuebao. Lixue ban, 2017 引入独立参数，应用权函数的方法及实分析技巧，建立一个具有最佳常数因子的半离散非齐次核的Hilbert型不等式，还考虑了其具有最佳常数因子的等价形式.
YANGBicheng(杨必成) +1 more
doaj +2 more sources
Research in the evaluating methods of the blind area radius of missile bullets(子母弹抛散盲区半径评定方法研究)
Zhejiang Daxue xuebao. Lixue ban, 2002 研究了导弹抛散盲区半径的评定方法.所谓盲区半径Rm,指的是以虚拟落点为圆心,子弹无法打到的圆域的半径.给出了几种不同的方法去评估盲区半径.首先,对于弹着点与圆心之间距离(即半径)的分布函数F(d),将Rm看作是分布函数F(d)的一个p分位点ξp,就可以利用矩法和极大似然法得到Rm(即ξp)的点估计;此外,将盲区半径指标Rm看成是一个随机变量,每次弹着点的最小半径作为样本值,通过直观的方法得到Rm的3种点估计.对于这些估计,给出它们的分布或近似分布,用经典方法可得到盲区半径的置信上限.最后给出了一个例子.
ZHANGGuo-fen(张帼奋) +1 more
doaj +1 more source
Zhongguo youzhi, 2023 为优化平面回转筛的结构和工艺参数，提高组合清理筛的筛分处理量和筛分效率，采用离散元软件EDEM对组合清理筛的平面回转筛分过程进行模拟仿真，探究颗粒在筛分过程中的运动规律，并仿真分析了回转半径、回转速度和筛面倾角对组合清理筛筛分处理量和筛分效率的影响。结果表明，提高回转半径、回转速度和筛面倾角均可提高组合清理筛筛分处理量，但会降低筛分效率（物料提取率和除杂率）。在回转速度为420 r/min左右、回转半径为20 mm左右、筛面倾角为7°~ 9°时，组合清理筛的筛分效率较好，筛分处理量也较大。In ...
张昊晨，张超，曹宪周，刘海芃，高涛 ZHANG Haochen，ZHANG Chao，CAO Xianzhou， LIU Haipeng，GAO Tao
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Dizhen xuebao, 2021 为分析场地的横向不均匀性对水平竖向谱比HVSR曲线产生的显著影响，本文基于Sánchez-Sesma等提出的扩散场方法，通过计算总波场格林函数虚部对二维沉积地形上的HVSR曲线进行模拟。格林函数虚部则通过刚度矩阵和平面内斜线格林函数采用间接边界元方法进行求解。对二维沉积地形和相应的一维层状半空间的HVSR曲线进行了参数分析，着重讨论了沉积地形的形状、相对计算点位置等因素对HVSR曲线的影响规律。结果表明：沉积地形内外材料阻抗比对HVSR曲线的影响最为显著 ...
Zhenning Ba +3 more
doaj +1 more source
Kongjian kexue xuebao, 2023 利用GUVI探测器观测的OI 135.6 nm气辉辐射数据，研究了2003年10月和11月两次持续时间不同的强磁暴期间气辉辐射强度经纬度分布及纬度–高度分布的变化。结果表明，全球大部分区域内OI 135.6 nm气辉辐射强度在磁暴期间会随着Dst指数的降低而增强，与磁暴的剧烈程度呈现准正相关关系。从纬度上看，气辉辐射强度的增强会由磁静期的磁赤道两侧附近向高纬地区延伸至南北半球50°附近，增幅基本在80%以上，最大可超过200%，且经纬度分布在磁暴期间的变化情况呈现出南北不对称性和纬向不对称性；从高度上看，
李 春来, 吕 建永, 李 婧媛
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Rare Metals, Volume 45, Issue 5, May 2026.ABSTRACT Arsenic presents a critical duality as both a hazardous environmental pollutant and an indispensable material for advanced semiconductor technologies. This study proposes an integrated reductive vacuum sublimation strategy, assisted by carbon and lead additives, to purify crude arsenic containing high oxygen (7.4%) and antimony (1326 mg kg−1).
Hongrui Xiang +6 more
wiley +1 more source
Rare Metals, Volume 45, Issue 4, April 2026.ABSTRACT The development of novel oxygen electrocatalysts with cost‐effectiveness, scalability, high catalytic activity, and stability presents a significant challenge for zinc–air batteries (ZABs). The nitrogen‐rich lignin coordination network structure is synthesized through amine modification of lignin.
Ping‐Xian Feng +8 more
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Rare Metals, Volume 45, Issue 1, January 2026.ABSTRACT Metal oxide semiconductor‐supported noble metal nanoparticles are common sensing materials for gas sensors. However, the large size and their tendency to migrate at high temperatures often lead to inferior sensing sensitivity and stability. Herein, a salt‐assistant strategy is developed to prepare fully‐exposed Ir clusters on SnO2 nanorods ...
Yi Jiang +7 more
wiley +1 more source
Evaluating protected areas’ coverage of threats to terrestrial biodiversity
Conservation Biology, Volume 39, Issue 6, December 2025.Abstract Protected areas (PAs) are vital for biodiversity conservation and have expanded globally. However, increasing pressures on biodiversity make it difficult to achieve conservation goals. Using threat probability maps based on the International Union for Conservation of Nature Red List and the World Database of Protected Areas, we analyzed the ...
Katherine Pulido‐Chadid +2 more
wiley +1 more source
Conservation Biology, Volume 39, Issue 6, December 2025.Abstract Pollinator conservation schemes typically focus on conserving existing, restoring degraded, or creating new wild bee habitats. Their effectiveness depends on dispersal corridors enabling habitat colonization by bees. However, the role of seminatural linear landscape structures (LLS) in connecting pollinator communities across intensively ...
Markus A. K. Sydenham +6 more
wiley +1 more source