Results 11 to 20 of about 800,294 (166)
核爆炸的大部分能量是以X射线形式释放的,研究X射线辐射特性对于天基核爆事件监测,当量反演都具有一定参考价值。根据核爆炸X射线能谱特性,构建了黑体辐射模型;根据NRLMSIS大气模型成分数据和高度密度数据,构建大气分层数值模型,并结合NIST数据库,构建分层大气质量吸收系数模型,提高了大气模型与大气质量吸收系数模型准确度。使用数值模拟程序对X射线在大气中的传输特性进行研究,模拟在临近空间高度核爆炸产生的X射线经过大气吸收后的能谱特性以及不同海拔高度点位的能注量。结果表明,在检测点高度恒定的情况下 ...
吕 致辉 +4 more
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特高压直流输电工程中,避雷器组在限制过电压过程中要吸收大量的能量,部分位置避雷器组的吸收能量设计容量达到30 MJ,需要大量电阻片组成上百柱并联进行分流,随之出现了部分电阻片老化较快率先损坏导致避雷器组故障的问题。为提升大规模多柱并联避雷器组运行可靠性,提出了基于避雷器组中各电阻片吸收能量均衡的配组算法。首先探讨了ZnO电阻片伏安特性分散性机理及统计规律,提出了配组算法流程,并根据实际避雷器组案例进行模拟计算。结果显示,经过迭代计算配组后的避雷器组在限制过电压过程中吸收能量分布更加均衡 ...
刘志远 +6 more
doaj
Visible‐Light‐Excited Optical Thermometry in Ca3Sc2Si3O12: Er3+ via an Efficient Eu2+ Bridge
ABSTRACT Er3+ ions are promising for optical thermometry due to their thermally coupled levels. However, their parity‐forbidden transitions result in weak and narrowband absorption, which restricts excitation to infrared lasers (e.g., 808, 980, or 1550 nm). Moreover, the single emission center inherently limits temperature sensitivity. In this work, we
Yi Liu +6 more
wiley +1 more source
ABSTRACT The development of lightweight, high‐attenuation, and broadband carbon‐based electromagnetic wave absorbers is hindered by the intrinsic trade‐off between impedance matching and dielectric dissipation. Herein, we report a facile and scalable synthesis of N‐doped lignin‐derived interconnected porous carbon (Nx‐LIPC) via hydrogen‐bond self ...
Bin‐Peng Zhang +7 more
wiley +1 more source
采用^15N-尿素进行盆栽和田间试验,研究了复合氮肥增效剂用量、尿素与复合氮肥增效剂配施对水稻生长、籽粒产量和氮素吸收利用的影响。结果表明,适宜用量(施氮量的20%)的复合氮肥增效剂能显著促进水稻幼苗生长发育;尿素全量配施复合氮肥增效剂不影响水稻生长,能显著提高水稻植株Ndff%、氮吸收总量,氮素利用率和^15N的吸收量,尿素减量5%~15%(即减少施氮7.8~23.7kg/hm^2)配施复合氮肥增效剂基本上不影响水稻生长、籽粒产量和吸氮总量,能显著提高氮素的农学效率、生理效率和氮素利用率;植株吸氮总量、
田秀英, 王正银
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直流换流站中性母线避雷器在限制过电压过程中需要吸收大量能量,因此采用大规模多柱并联结构。为了研究中性母线多柱并联避雷器组的故障暂态特性,基于宁东-青岛±660 kV特高压直流输电工程,利用PSCAD程序建立系统仿真模型,计算避雷器组参数并建立多柱并联避雷器组模型,仿真得到不同运行方式下典型故障时中性母线避雷器过电压、电流及吸收能量的波形,分析波形特征。研究避雷器组自身发生击穿故障时的特性以及对系统的影响。仿真结果显示,在发生单极阀顶接地故障时中性母线EM避雷器吸收能量21 MJ,当某一柱伏安特性降低10%
刘志远 +6 more
doaj
ABSTRACT Because magnetic permeability is an intrinsic property of materials, achieving the regulation of magnetic loss is one of the challenges for electromagnetic wave absorption materials. This paper focuses on the research idea of in situ growth of dispersed nanocrystalline FeSiB in an amorphous FeSiB matrix to regulate magnetic properties.
Lei Wang +4 more
wiley +1 more source
110 kV并联电容器装置具有单组容量大、电压等级高的特点,而其结构形式和运行工况又与传统并联电容器装置有所区别,因此研究其避雷器参数合理选取原则对于提高其经济性和安全可靠性具有重要意义。以特高压工程110 kV/240 MVA并联电容器装置为研究对象,对其正常分闸重击穿以及单相接地故障情况下单相重击穿时出现的过电压水平进行了理论分析,并在此基础上建立了避雷器吸收能量仿真模型,仿真分析了各种重击穿情况下避雷器的吸收能量以及运行工况对避雷系吸收能量的影响规律,最终提出了最严重工况下避雷器吸收能量的选取建议:
何慧雯, 尹婷, 马跃, 王子建
doaj
Read the free Plain Language Summary for this article on the Journal blog. Abstract Human‐driven landscape change, particularly urbanization, is reshaping pollinator communities, yet the functional traits that mediate species persistence remain poorly understood. Dietary specialization is commonly used to predict species vulnerability.
Yan Yang +5 more
wiley +1 more source
ABSTRACT Magnesium (Mg)‐based composites are regarded as promising lightweight materials with significant potential for structural applications. The structure–property relationships of bionic Mg‐based composites remain unclear. Herein, three honeycomb‐like Mg‐Fe composites are fabricated to uncover the underlying strengthening mechanisms.
Fan Zhang +5 more
wiley +1 more source

