Results 31 to 40 of about 25,302 (204)

Al2O3添加剂对粘土莫来石化反应的影响

open access: yesDianci bileiqi, 1989
粘土莫来石化反应取决于所研讨的Al2O3的添加量、反应时间与反应温度.使用的粘土为含有一定量石英的高岭土.粘土莫来石化的动态分析证明,核晶模型成功地描述了1200℃~1300℃温度区间内的反应过程.试验测得这种反应的活化能在105~173kJ/mol范围内.添加5%Al2O3的粘土测得的活化能最低.添加浓度较高时粘土莫来石化过程的活化能试验值比不含添加剂时高.结果表明,采用Al2O3作为添加剂不仅能改善机械性能,而且对粘土莫来石化进程也起到影响.
庄子茹
doaj  

Catalytic Activity of Ni/CeO2-ZrO2@SiO2Core-Shell Structure for Steam Reforming of Toluene [PDF]

open access: yes, 2017
本文通过结构导向法制备一系列不同壳层厚度的Ni/Ce-ZrO2@SiO2催化剂,并将其应用到生物质焦油模型甲苯的蒸汽重整反应中。采用XRD、SEM、TEM和XPS等对催化剂的形貌及结构进行表征。结果显示,多孔SiO2层的存在能显著提高催化剂的性能,能通过修饰Ni的能带结构,改善Ni的本征活性并改变产物分布。SiO2壳层厚度对催化剂的性能也有影响,在一系列不同壳层厚度的Ni/Ce-ZrO2@SiO2催化剂中,壳–核质量比为0.5的催化剂表现出最高的催化活性,该催化剂在650℃和700 ...
张亮, 赵效勇, 闫常峰
core   +1 more source

When and why to give shorebirds a head start

open access: yesConservation Biology, EarlyView.
Abstract Headstarting is a translocation technique involving the hatching or rearing of wild eggs or young in captivity and the release of those individuals back to the wild at or before independence. It has been trialed as a conservation intervention for shorebirds over recent decades to improve the population trend of target populations by increasing
Lynda Donaldson   +4 more
wiley   +1 more source

The in-situ spectroscopy study of the catalytical oxidation of CO and CH4 [PDF]

open access: yes, 2015
本论文工作着重考察了Pt和Pd贵金属基底上氧化物薄膜以及反应条件下可能生成的超薄氧化物膜对CH4或CO催化氧化性能的影响。超高真空原位红外光谱高压反应池的巧妙设计,可以观察到红外光谱中较低波数区间内可归属于金属-氧键的振动信息在反应过程中的变化。 通过模型催化剂多晶Pd和Pt表面上CH4氧化反应动力学曲线的鲜明对比,结合原位红外谱学证据,我们成功地探明了600~800K温度区间内PdO与金属Pd的生成与O2分压的关系以及相对催化活性,而Pt表面始终以金属态形式存在 ...
翁雪霏
core  

In vitro culture, cryopreservation, and field reintroduction of the endangered Mingan thistle

open access: yesConservation Biology, EarlyView.
Abstract Current plant conservation efforts are hindered by, for example, poor seed germination, low viability, and insufficient propagation and preservation technologies. To address these problems, we devised an approach to plant conservation that integrates conservation, preservation, and restoration (CPR), which uses advanced in vitro techniques. We
Mukund R. Shukla   +4 more
wiley   +1 more source

Strengthening community‐based fisheries monitoring programs with Indigenous perspectives

open access: yesConservation Biology, EarlyView.
Abstract Community‐based monitoring (CBM) programs are increasingly recognized as essential for adaptive environmental stewardship. Yet, the CBM literature often highlights successful cases and privileges evaluations by external experts over those of community members themselves.
Kanwaljeet Dewan   +2 more
wiley   +1 more source

教學活化導向深度學習 Conceptualizing Teaching Activating Towards Deeper Learning

open access: yesJournal of Curriculum Studies, 2020
因隨社會快速變遷,教學不僅引導學生有意義學習,更協助他們在迎接新世紀工作和生活時,能有效地適應不斷變化的情況,深度學習在協助學生發展遷移知識,轉化於新問題及新情境中扮演核心要件。臺灣國教改革以素養導向期待學生學習能超越行為能力及技術本位的觀點,學習共同體、合作學習、翻轉學習等教學不斷推陳出新,活化教學成了教改的熱門議題。活化具催化行動的概念,相對於僵化、靜止,從過去湧向未來,不斷湧出的活水泉源,更是成為引導學生深度學習的關鍵議題。本文首先探討活化教學的意涵 ...
林佩璇 Pei-Hsuan Lin
doaj   +1 more source

Lignin and lignin-acetoderivative oxidative degradation into valuable aromatic aldehydes [PDF]

open access: yes, 2015
本项工作研究了木质素的转化以及其副产品(乙酸基衍生物)转变为高附加值的芳香醛,乙酸基衍生物在碱性条件下催化氧化降解的动力学方程等问题。竹材木质素被转化为高附加值的芳香醛和乙酸基衍生物。在铜作为催化剂的条件下,香草乙酮被转化为香草醛。另外,乙酰丁香酮首次转化为丁香醛,从而通过降解木质素氧化过程中的副产物来提高整个过程的价值。本文用GC-MS分析得到了一种可靠的一致的相对影响因子法来定量木质素和乙酸衍生物。竹材木质素的总产率接近9.5%,且香草醛的产率为55%,其中90%以上来自于香草乙酮。来源于木质素 ...
KISSA RAJIF ALUNGA
core  

Synthesizing beaver coexistence messaging with the capability, opportunity, and motivation behavior model

open access: yesConservation Biology, EarlyView.
Abstract In the western United States, conservation practitioners are increasingly working with private landowners to restore habitat for North American beavers (Castor canadensis) and to use nonlethal mitigation techniques when beavers damage crops and infrastructure.
Brian D. Erickson, Megan S. Jones
wiley   +1 more source

Effects of ammonia-N and nitrite-N on immune enzymes of Macrobrachium rosenbergii(氨态氮、亚硝态氮对罗氏沼虾免疫相关酶类的影响)

open access: yesZhejiang Daxue xuebao. Lixue ban, 2005
氨态氮和亚硝态氮是虾类养殖环境中最主要的污染物.在1 mg/L非离子氨态氮和1 mg/L亚硝态氮的作用条件下,罗氏沼虾血清、肝胰腺和肌肉中的酚氧化酶、超氧化物歧化酶、碱性磷酸酶及酸性磷酸酶活力变化不同,经1、4、7及10天处理后,血清和肌肉酚氧化酶活力均有所降低,而肝胰腺的酚氧化酶活力则略有增高;各组织中的超氧化物歧化酶活力基本变化过程为,先增高后降低;各组织的两种磷酸酶活力则有不同程度的增高.酚氧化酶与超氧化物歧化酶活性可作为判断虾类免疫抗病能力的指标,而两种磷酸酶活性则仅可作辅助参数.
WANGYue(王玥)   +2 more
doaj   +1 more source

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