Results 11 to 20 of about 7,427 (154)

Biodiversity‐driven spatial conservation planning to delineate temporally stable regions

open access: yesConservation Biology, EarlyView.
Abstract The accelerating loss of biodiversity underscores the critical need for effective conservation strategies, particularly in the face of climate change and anthropogenic pressures. We devised a conservation planning framework that adopts a temporal stacking approach to species distribution models and landscape connectivity analyses. These models
Mattia Iannella   +5 more
wiley   +1 more source

In-situ visualization of nanosecond laser-materials processes and the functional structures preparation of thin film [PDF]

open access: yes, 2016
新型材料和新结构的开发和利用一直是微电子和光电子领域的研究热点,而与传统材料加工技术相比,纳秒脉冲激光技术在材料功能性结构制备领域具有得天独厚的优势:首先是非接触加工,材料兼容性强;其次是适合微小尺寸加工,通过控制激光光斑形状和尺寸可以制备尺寸可控的表面功能性结构;更为重要的是纳秒脉冲激光可以实现激光能量在超短时间内与材料发生相互作用,因此纳秒脉冲激光加工技术在材料表面微结构制备领域占有举足轻重的地位 ...
亓东锋
core  

500kV直流断路器快速机械开关典型故障特性及可靠性提升方法研究 [PDF]

open access: yes, 2023
直流断路器是构建柔性直流电网不可或缺的关键设备。快速机械开关是直流断路器中承载电流、实现快速分合闸、耐受分闸恢复电压的核心组件,其结构复杂、动作速度快、电气应力严酷、可靠性要求高,因而设计研制难度大,任一环节出现问题均会影响直流断路器乃至柔直电网的安全可靠运行。然而,目前快速机械开关由于存在设计选型不合理、工艺管控不严格、试验考核不完善等问题,导致在实际工程应用中故障率较高。针对已应用于张北柔性直流电网试验示范工程的500 kV直流断路器,分析了直流断路器研制、调试 ...
张涛   +4 more
core   +1 more source

Experimental insights into characteristic properties and applications of two‐dimensional Janus transition metal dichalcogenide (TMDC) materials: a comprehensive review

open access: yesRare Metals, Volume 44, Issue 11, Page 8161-8197, November 2025.
Graphical abstract AbstractThe studies on the synthesis of two‐dimensional (2D) Janus materials have made significant progress over the years. They offer new opportunities to increase the potential usage of Janus transition metal dichalcogenide (TMDC) materials in different application areas due to their unique structural, electrical, optical and ...
Ayça Coşkun   +9 more
wiley   +1 more source

Study on Target Detection Method by Coherent Integration for Frequency Modulation Coded Radar Systems [PDF]

open access: yes, 2016
在现代战场上,高速低可侦测性目标以及各种电子干扰手段的出现对雷达的目标探测性能提出了更高的要求。调频编码雷达作为一种新型的高距离分辨率雷达,具有数据利用率高、对雷达瞬时带宽要求不高以及抗干扰性能强的优点。为了增强调频编码雷达对微弱目标的检测能力,进一步研究调频编码雷达的相干积累检测方法具有重要意义。因此,本文主要开展了如下创新工作: (1)针对调频编码雷达,提出了一种基于运动补偿的相干积累检测方法。首先对调频编码雷达的回波信号进行建模,利用最大似然估计 ...
王智灵
core  

Next‐Generation Sequencing of Fecal DNA: A Novel Insight Into the Mitogenome Phylogeography of the Snow Leopard (Panthera Uncia) 粪便dna的二代测序:对雪豹线粒体组谱系地理结构的新洞察

open access: yesIntegrative Conservation, Volume 4, Issue 3, Page 277-286, September 2025.
This study provides an innovation to address the challenge in accessibility to samples and genetic markers in Snow leopard conservation genetic studies. We performed next‐generation sequencing (NGS) on 19 fecal samples obtained from the eastern Qinghai‐Tibet Plateau, and successfully assembled 17 complete mitogenome sequences (~16,720 bp) and ...
Chen Cheng   +7 more
wiley   +1 more source

MMSE whitening in noncoherent decorrelative detection for nonorthogonal multi-pulse modulation [PDF]

open access: yes, 2005
码分多址(CDMA)技术的通信系统是一种自干扰受限系统,每个用户唯一的扩频码为用户实现了在时间和频率上的共享,由于各种原因使得扩频码不能完全正交,由此产生多址干扰(MAI);还有用户距离基站的远近带来的远近效应(Near-FarEffect)问题。这些因素严重限制着通信系统性能和容量,因此如何使用先进的信号处理技术来抑制这些不利因素成为CDMA通信系统中的关键技术,而多用户检测技术能够有效解决这些问题。本文主要研究了非正交多脉冲调制(NMM)信号的多用户检测技术。研究的主要内容及创新点包括以下几个方面 ...
江慧琴
core  

Effectiveness of protected areas in the Caucasus Mountains in preventing rangeland degradation

open access: yesConservation Biology, Volume 39, Issue 3, June 2025.
Abstract As land use intensifies globally, it increasingly exerts pressure on protected areas. Despite open, nonforested landscapes comprising up to 40% of protected areas globally, assessments have predominately focused on forests, overlooking the major pressures on rangelands from livestock overgrazing and land conversion.
Arash Ghoddousi   +12 more
wiley   +1 more source

腔内滤波带宽对正色散束缚态孤子形成的影响 [PDF]

open access: yes, 2019
以被动锁模正色散掺镱(Yb)光纤激光器为研究对象,实验比较研究了激光腔内滤波带宽对产生正色散束缚态孤子的影响。采用高掺Yb光纤作为增益介质,半导体饱和吸收镜作为锁模部件,获得1064 nm全光纤线型腔锁模激光器。当腔内带通滤波器选用不同带宽(0.2,1.0,1.2,2.3 nm)时,观察到不同的皮秒锁模脉冲状态。在滤波带宽较小(0.2 nm)或较大(2.3 nm)时,仅产生稳定的单脉冲耗散孤子;相反地,在滤波带宽适中(1.0 nm或1.2 nm)时,分别观察到典型的相位差为π和-π/2束缚态耗散孤子 ...
李维炜   +5 more
core   +3 more sources

多脉冲下架空线缆耦合雷电电磁波特性分析

open access: yesDianci bileiqi, 2020
传输线缆在电力输送和信号传输领域中扮演着十分重要的角色,传输线耦合雷电电磁波产生的过电压、电流对整个传输线系统产生很大的影响。本文通过建立架空线缆、闪电通道一体化模型。利用模拟8/20μs单脉冲雷电流及多脉冲雷电流进行试验,得出结论如下:架空线缆耦合电压波形以阻尼振荡波形式衰减;耦合电压幅值整体随冲击电流的增大而增大,多脉冲条件下耦合电压幅值与冲击电流峰值不是对应的比例关系;单脉冲冲击下,耦合的能量随冲击电流峰值以指数形式增加,多脉冲冲击下,耦合的能量整体随冲击电流峰值的增加而增加 ...
申东玄, 杨仲江, 王梧熠
doaj  

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