Results 11 to 20 of about 86,373 (159)
, 1979 六十年代中期,美国和加拿大在离心压气机的研究工作中获得了新的突破,他们分别研究成功了单级压比为6～10的离心压气机,从此,高压比离心压气机就成为叶轮机械研究工作中一个很活跃的领域。本文首先介绍高压比离心压气机的发展过程和现状,然后着重对提高离心压气机元件性能和改善设计方法的若干问题进行了讨论 ...
刁正纲, 陈静宜
core +2 more sources
, 1980 一、引言测量气体流速通常用皮托管。皮托管用来测量气流的总压和静压之差,也就是动压,而求出气体的流动速度。这样,流速的测量也能归结为气体压差的测量。测量气体压差还可用来测量流动管道各段的压头损失和动力源(如风机等)的增压。一般来说,测量气体压差有多种方法。U管压强计、斜管式压强计,双液式差压计是其中的一些常用方法。所充的液体也根据不同的测试要求和范围,有水银、水、酒精 ...
林光海
core +2 more sources
Scientists’ warning on the global destruction of rock outcrop ecosystems
Conservation Biology, EarlyView.Abstract Rock outcrops are geological formations that harbor a highly specialized biota adapted to harsh environmental conditions that differ from their surrounding landscapes. They are globally distributed, especially in old, highly weathered landscapes, and can function as habitat islands containing high levels of endemism and distinct evolutionary ...
Luiza F. A. de Paula +19 more
wiley +1 more source
Intact coastal nursery rearing amid climate‐driven phenological shifts in threatened salmon
Conservation Biology, EarlyView.Abstract Literature linking phenology to climate has proliferated in recent decades and shows that climate change has reorganized seasonal opportunities worldwide. However, this literature often quantifies changes in point measures of timing (e.g., beginnings and peaks) without context about duration (e.g., rearing season length) or performance (e.g ...
Stuart H. Munsch +8 more
wiley +1 more source
, 1993 本文给出了一种用于磁盘机读/写功能的非接触起停式负压磁头滑块模型。通过求解修正Reynolds方程,计算出其稳态气动力特性。给出了磁头滑块与磁盘之间润滑气膜压强分布的立体图,滑块工作曲线及压力载荷随磁盘线速度、气膜厚度 ...
孙征, 傅仙罗
core +2 more sources
Policy Studies Journal, Volume 54, Issue 4, November 2026.ABSTRACT This paper examines how governments navigate policy legitimacy during crises through three distinct discursive processes: legitimization, delegitimization, and blame avoidance. Using a sequential mixed‐methods design, the study analyzes Denmark's decision to cull all mink during the COVID‐19 pandemic. The quantitative analysis of 947 newspaper
Olivier Rubin +3 more
wiley +1 more source
Rare Metals, Volume 45, Issue 9, September 2026.ABSTRACT The escalating severity of global environmental pollution necessitates the development of sustainable and efficient adsorption materials. Nanocellulose (NC), sourced from the most abundant natural polymer on earth, has shown great potential in this field due to its renewability, biodegradability, and exceptional nanoscale properties.
Yaqian Yu +5 more
wiley +1 more source
Gaoya dianqi, 2021 为掌握SF6气体的低温放电特性,保证低温环境下SF6气体设备的运行可靠性。文中开展了-50℃至20℃温度范围内,半球头棒板电极下SF6气体的工频击穿试验。同时测量了降温过程中SF6气体的气压随温度的变化。获得了稍不均匀电场中绝对气压0.7 MPa和0.5 MPa的SF6气体的放电电压随温度的变化规律。发现当温度从20℃降低到-50℃时,SF6气体的放电电压和气压均呈现先缓慢降低,再迅速降低趋势,放电电压下降趋势的拐点与气压下降趋势的拐点基本一致,计算发现该拐点温度等于SF6气体的液化温度 ...
王远东 +6 more
doaj
Rare Metals, Volume 45, Issue 8, August 2026.ABSTRACT Solar‐blind ultraviolet (UV) photodetectors (SBPDs) play a critical role in applications including UV communication and fire warning systems. Gallium oxide (Ga2O3) has emerged as a promising material due to its wide bandgap and low cost, but suffers from high dark current and slow response speed caused by oxygen vacancy (VO) defects. This work
Yuhao Lin +14 more
wiley +1 more source
Gaoya dianqi, 1996 一、概述 SF6气体断路器最初是类似空气断路器的双压式断路器。这种断路器用气泵将SF6气体压入高压贮气室,在开断时,气体从高压贮气室流入气压较低的灭弧室,从而产生气吹作用将电弧熄灭。这种断路器由于充气压力高,SF6气体易液化,使用极不方便。另外,它需要一套抽气系统,结构非常复杂。而后的压气式断路器,在开断短路电流时 ...
游一捷
doaj