Results 31 to 40 of about 27,018 (162)
Nitrogen speciation and stable nitrogen and oxygen isotopic compostions of maritime aerosol in spring over the continental shelf sea in eastern china and the Northwest Pacific Ocean [PDF]
大气气溶胶是大气化学中多相反应的催化剂,其化学成份极其复杂。人类活动释放到大气中的不同形态的活性氮是大气气溶胶中一个重要的组成部分。在东亚冬季季风的驱使下,含有活性氮的气溶胶可以在大气中长距离传输并沉降到下风向区域的边缘海和开阔大洋。稳定氮同位素可用于追溯海洋源气溶胶中活性氮的主要来源及其在大气中的化学过程。但由于氮同位素在大气传输和化学转化过程中的分馏效应,使得其应用变得复杂。起源于西伯利亚的东亚冬季季风通过人为活性氮排放强烈的中国东北后又覆盖了整个中国东部陆架海和西北太平洋海域,而且在该海域的春季 ...
罗笠
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ABSTRACT Alkali metal–chalcogen batteries (AMCBs) are one of the most promising next‐generation energy storage systems because of their high energy density and reasonably low cost. However, the practical application of AMCBs is severely hindered by the volume expansion of the chalcogen cathode, the shuttle effect of polychalcogenides, and unstable ...
Yong Liu +11 more
wiley +1 more source
以太湖地区典型水稻土——水耕铁渗人为土为供试材料,通过添加CaCO3和H2SO4培养及滴定的方法,研究不同pH降雨和施氮对土壤酸碱缓冲体系的影响。结果显示,土壤在添加CaCO3和H2SO4培养后进行不同量酸碱滴定,土壤在pH 4.0~7.5的突跃范围内与酸碱加入量呈显著的线性相关,表明该测定方法对供试土壤适用。同时施氮和降雨对土壤的酸化都有加速作用,各处理0-40 cm层土壤酸碱缓冲容量为1.91~2.20 cmol/kg,增加施氮量、降低降雨pH都降低土壤的酸碱缓冲容量 ...
汪吉东 +6 more
doaj
Nitrogen cycle in the northern South China Sea: insights from stable N isotopic composition [PDF]
氮是海洋初级生产力的主要限制因素之一,进而影响有机物输出,因而调控海洋生物泵效率和大气二氧化碳水平。因此,海洋氮循环过程与碳、磷等其它生源要素的循环紧密联系,在海洋生物地球化学循环过程中扮演极其重要的角色。另一方面,自工业革命以来人为活动对海洋氮循环的影响日益增长,至今人类活动向海洋排放的氮通量已与海洋生物固氮作用的通量相似。因而,海洋氮循环将如何响应人类活动对其的胁迫已成为海洋生物地球化学研究的热点问题。 陆架边缘海连接陆地和开阔大洋,是氮循环过程极其活跃,也是最为复杂的区域 ...
杨进宇
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ABSTRACT Piezocatalytic technology utilizes mechanical strain or stress‐induced piezoelectric phenomena to produce robust internal electric fields, markedly improving the separation efficiency of e−‐h+ pairs. This method has emerged as a focal point in catalysis by removing reliance on conventional light or electrical energy via its mechanical‐to ...
Yue Zhou +5 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
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
Different forms of nitrogen contents and their vertical variations of transformation modes of the sediments of Lake Yuehu, Wuhan [PDF]
Vertical distributions of nitrogen contents, net nitrification rates, net N-mineralization rates and nitrate reductase activities in sediments of Lake Yuehu in June, 2005, were described on basis of four samples from the lake.
Chen Guoyuan +5 more
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ABSTRACT The dual challenges of environmental sustainability and rising energy needs underscore the necessity for high‐energy‐density batteries, making lithium–sulfur (LSB) systems with their high theoretical capacity highly attractive. However, the polysulfide shuttle, coupled with inherent kinetic limitations in the sulfur reduction reaction ...
Bingbo Ni +4 more
wiley +1 more source
Preparation and Photoluminescence of Praseodymium-Doped Silicon Aluminum Oxynitride Phosphors by Polymer-Derived Method [PDF]
应用先驱体转化法制备稀土掺杂硅基氮氧化物荧光粉,可以改善传统的固相反应法所需要的高温高压等苛刻条件。掺镨含铝硅基氮氧化物红色荧光粉具有较好的发光稳定性及化学稳定性,在显示照明领域具有潜在的应用价值。目前,尚没有先驱体转化法制备掺镨含铝硅基氮氧化物红色荧光粉的报道,因此,有必要探讨先驱体转化法制备该荧光粉的合成工艺及参数。本论文采用聚碳硅烷、乙酰丙酮镨和乙酰丙酮铝为原料,通过聚合反应得到先驱体,在氨气中经氮化实现有机-无机转化,再经结晶制备掺镨含铝硅基氮氧化物荧光粉。系统研究了烧结温度、投料原子比 ...
余辉
core
ABSTRACT Graphitic carbon nitride (g‐C3N4) doped with 3d transition metals (3d‐TM@g‐C3N4) has gained attention as a noble metal‐free alternative for oxygen evolution and reduction reactions (OER/ORR). Yet the key mechanisms driving its performance remain debated, especially across different charge states.
Jing Zhang +6 more
wiley +1 more source

