Results 21 to 30 of about 26,472 (207)

Systematic Study of Fermi‐Level Pinning at Crystalline Metal/GaN Interfaces: First‐Principles Calculations and Diode Characterization

open access: yesRare Metals, EarlyView.
ABSTRACT The Schottky barrier height (SBH), which serves as a pivotal determinant of charge carrier injection efficiency in electronic devices, critically governs electrical behavior at metal/semiconductor interfaces. However, pronounced metal‐induced gap states at metal contact interfaces induce Fermi‐level pinning, which constrains the ...
Xiaofei Liu   +10 more
wiley   +1 more source

免耕和草篱措施对径流中典型农业面源污染物的去除效果

open access: yesShuitu Baochi Xuebao, 2011
大量施用农业化学物质在提高作物产量的同时,也导致了严重的水体污染。在北京地区不同坡度的径流小区上,通过人工模拟降雨试验,研究免耕、草篱、以及免耕与草篱复合3种措施对农田径流中氮、磷、阿特拉津3种典型农业面源污染物的去除效果。结果表明:免耕措施可减少53%的总氮、51%的总磷和56%的阿特拉津流失;草篱措施可减少68%的总氮、61%的总磷和90%的阿特拉津流失;而免耕与草篱复合措施可减少77%的总氮、76%的总磷和92%的阿特拉津流失。另外,总氮、总磷和阿特拉津流失量均与径流量呈显著的线性正相关关系 ...
李霞   +4 more
doaj  

Sedimentary Nitrogen Removal in the Pearl River Estuary in Autumn [PDF]

open access: yes, 2015
珠江口作为珠江流域的入海口,位于华南广东省的最南端,其南面通向南海北部,周围紧邻着经济高度发达、人口稠密的珠江三角洲经济区。珠江口的氮循环受到周边区域的工业、农业、水产养殖和生活污水排放的影响日益严重,富营养化等一系列相关的生态负面效应随之而来。珠江口内部氮元素的迁移转化情况亟待研究了解。 本研究主要专注于珠江口内的水环境中沉积物内各种氮移除过程及其脱氮速率。 本研究采用了目前在脱氮研究领域最先进的同位素配对技术计算模式,此方法用氧化亚氮的氮同位素比值修正了厌氧铵氧化对反硝化速率计算造成的干扰 ...
江新磊
core  

Precise Tailoring of the Coordination Environment of Single‐Atom Cu(I) on Trifurcate AlL3 Supports for Click Chemistry

open access: yesRare Metals, EarlyView.
ABSTRACT Single‐atom catalysis hinges on fundamental challenges in precisely controlling metal‐support interactions and rationally regulating metal–adsorbate relationships. Herein, we report a universal strategy for constructing highly efficient and well‐defined Cu(I) single‐atom catalysts based on a trifurcate AlL3 molecular support.
Donghui Zhang   +9 more
wiley   +1 more source

福州不同农田土地利用类型土壤碳氮磷生态化学计量学特征

open access: yesShuitu Baochi Xuebao, 2019
为阐明不同土地利用类型土壤碳(C)、氮(N)、磷(P)生态化学计量学特征,对福州农田不同土地利用类型(水稻田、菜地和茉莉园)下的土壤全碳(TC)、全氮(TN)、全磷(TP)含量及其生态化学计量学特征进行测定和分析。结果表明:土壤TC含量均值基本表现为水稻田 > 菜地 > 茉莉园(P 菜地 > 茉莉园(P 水稻田 > 茉莉园 ...
刘旭阳   +5 more
doaj  

Study on the carbonitriding cast iron by liquid micro-discharge plasma [PDF]

open access: yes, 2016
液相微弧放电等离子体电解碳氮共渗技术是一种新兴的表面改性技术。相对于传统表面改性技术,它具有能耗低、不需要真空装置、成本小、环境污染小、工艺简单等特点,在航空航天、军工、机械、电子、医疗、装饰等许多领域具有广阔应用前景。 本论文采用液相微弧放电等离子体电解碳氮共渗技术,在乙酰胺甘油水溶液电解液体系中对铸铁表面进行了碳氮共渗处理。电源参数为:电流大小固定为3A,频率固定为100Hz,占空比固定为25%;电解液配方为:去离子水750mL,乙酰胺150g,甘油80mL ...
李俊雄
core  

A Molten Salt Strategy to Convert Bulk Nb2O5 Into 2D Nonlayered Niobium Nitride Nanosheets for Superior Pseudocapacitive Storage

open access: yesRare Metals, EarlyView.
ABSTRACT Two‐dimensional (2D) nonlayered niobium nitrides have attracted considerable interest for electrochemical energy storage. However, the synthesis of these materials is hampered by their nonlayered crystal structures, which are characterized by strong three‐dimensional chemical bonding.
Rui Huo   +7 more
wiley   +1 more source

干旱河谷-山地森林交错带植被调控模式对土壤氮、磷强度及库的影响

open access: yesShuitu Baochi Xuebao, 2011
以调控30个月的4种典型调控模式以及未调控退耕纯林为研究对象,比较分析了不同调控模式下氮、磷供强度及库容特征.结果表明,相对于纯林模式,4种调控模式均可有效缓解缺氮少磷的土壤现状,提高或增加了固氮效率以及氮、磷储量,且表现出氮、磷元素聚表分布(0-10 cm)的特征;表层土(0-10cm)中,刺槐+扁桃+紫花苜蓿模式的氨态氮含量(10.52士0.34 g/kg)、硝态氮含量(11.69±1.06 g/kg)显著高于其它模式,对植物生长极为有利,但对氮、磷的储存贡献较小;刺槐+新疆杨 ...
刘彬   +7 more
doaj  

人工湿地强化脱氮系统运行条件优化研究 [PDF]

open access: yes, 2013
微生物的硝化与反硝化作用是人工湿地脱氮的主要途径,如何调控与优化湿地沿程溶解氧浓度和污水碳氮比,对于提高人工湿地脱氮效果至关重要。为此,在人工湿地前端埋设曝气管、后端增设碳源投加管,构建了一种人工湿地强化脱氮系统,并选择曝气速率、曝气运行/停止时间比、碳源投加量、进水方式进行正交试验,开展了人工湿地碳氧联合调控脱氮研究。结果表明,各因素的影响大小依次为:曝气运行/停止时间比>曝气速率>碳源投加量>进水方式;最优运行条件为:曝气速率为2.5 L·h-1,曝气运行/停止时间比为8 h/16 h ...
屈娟娟   +4 more
core  

An Ultrasmall Strontium‐Loaded Polydopamine Nanoformulation for Near‐Infrared‐Enhanced Periodontitis Therapy via Photodynamic Gas‐Promoted Antibacterial and Bone Repair

open access: yesRare Metals, EarlyView.
ABSTRACT Periodontitis is a chronic infectious oral disease triggered by periodontopathogenic bacteria, resulting in the progressive inflammation and destruction of the tissues surrounding teeth. To achieve reprogramming of the infectious microenvironment for periodontitis therapy, a nanoformulation was proposed by loading polydopamine (PDA) with ...
Hao Liang   +14 more
wiley   +1 more source

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