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热喷涂参数对喷涂WC-Co合金表面温度的影响

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沈阳建筑大学学报（自然科学版） 2006年第6期22卷 1052-1056页

作者：赵民 r.gadow A.Kirringer A.Cander-ruiz 沈阳建筑大学交通与机械工程学院辽宁沈阳110168 Institut für Fertigungstechnorogie keramischer Bauteire University of StuttgartGermany

目的建立在线检测系统,控制在高速氧气燃料(HVOF)热喷涂加工过程中加工参数,以获得最佳机械性能的硬质合金(WC-Co)涂层.方法采用热喷涂加工方法把金属,金属陶瓷和陶瓷材料以熔融状态和半熔状态沉积在各种预先处理的基体上.通过使用HVOF... 详细信息

目的建立在线检测系统,控制在高速氧气燃料(HVOF)热喷涂加工过程中加工参数,以获得最佳机械性能的硬质合金(WC-Co)涂层.方法采用热喷涂加工方法把金属,金属陶瓷和陶瓷材料以熔融状态和半熔状态沉积在各种预先处理的基体上.通过使用HVOF喷涂加工技术生产WC-Co合金表面涂层,采用红外线温度测量仪对不同参数加工表面涂层的温度进行了测量.基于热量传递理论和物理量纲分析方法建立了涂层表面温度和加工参数之间的理论公式.结果涂层表面温度与热功率成正比而与喷枪的移动速度和靶距成反比.靶距对涂层表面温度的影响要比速度对涂层件表面温度的影响大,转动角度对涂层表面温度有一定的影响.结论用温度作为中间变量来控制加工参数.采用一定的表面温度测量方法,提取信号并控制主要参数,从而实现工艺参数-表面温度-加工质量闭环系统控制,以达到最佳表面质量.

关键词： HVOF热喷涂红外线测量 WC-Co涂层表面温度

HVOF喷涂参数对WC-Co涂层力学性能的影响

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沈阳建筑大学学报（自然科学版） 2007年第4期23卷 668-671页

作者：赵民张云凤 r.gadow Antonio Candel-ruiz 沈阳建筑大学交通与机械工程学院辽宁沈阳110168 Institutfr Fertigungstechnologie keramischer Bauteile University of Stuttgart

目的研究HVO下在不锈钢上热喷涂WC-Co合金涂层喷涂参数如速度和靶距对涂层力学性能的影响,揭示其对表面残余应力,表面硬度的影响机理,优选最佳工艺参数.方法使用HVOF在不锈钢表面喷涂WC-Co合金形成耐磨涂层,通过使用显维硬度测量和钻孔... 详细信息

目的研究HVO下在不锈钢上热喷涂WC-Co合金涂层喷涂参数如速度和靶距对涂层力学性能的影响,揭示其对表面残余应力,表面硬度的影响机理,优选最佳工艺参数.方法使用HVOF在不锈钢表面喷涂WC-Co合金形成耐磨涂层,通过使用显维硬度测量和钻孔方法来测量不同加工参数下的涂层硬度和残余应力分布.结果涂层和基体上存在3个区域,在这3个区域内硬度和残余应力完全不同的,但它们的变化趋势是一致的.涂层最大硬度并不是在表面,而是距离表面为40μm.结论通过比较不同参数下的涂层力学性能,可以确定最佳加工参数,通过试验发现喷枪速度小,靶矩小,涂层内部残余应力加大,同时显微硬度也有所提高.

关键词： HVOF WC—Co涂层喷涂参数力学性能

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连续纤维强化零件的半固态锻造

锻造与冲压 2006年第2期 75-76页

作者： K. Siegert M. Liewald P. Unseld r.gadow K. v. Niessen Institut fuer Umformtechnik (IFU) Institut fuer Fertigungstechnologie keramischer Bauteile (IFKB)

在航空和汽车工业中，低能耗和低排放的要求增加了对高刚度和高强度轻质材料的需求。金属材料潜在的特殊性能的增强是通过纤维强化来实现的。这些材料有大量的存在形态并允许进行各种强化处理。因此，保持有非常特别的机械和良好物理性... 详细信息

在航空和汽车工业中，低能耗和低排放的要求增加了对高刚度和高强度轻质材料的需求。金属材料潜在的特殊性能的增强是通过纤维强化来实现的。这些材料有大量的存在形态并允许进行各种强化处理。因此，保持有非常特别的机械和良好物理性能（热延性、抗冲击性和抗腐蚀性）的特制准各向同性或各向异性材料可以获得。

关键词：纤维强化半固态锻造零件各向异性材料轻质材料准各向同性汽车工业特殊性能金属材料

Stabilizing forest productivity and resilience at multiple scales

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Forest Ecosystems 2023年第5期10卷 561-568页

作者： Klaus v.gadow Faculty of Forestry and Forest Ecology Georg-August-University GöttingenBüsgenweg 5D-37077GöttingenGermany Department of Forestry and Wood Science Faculty of AgriSciencesStellenbosch UniversityMatielandSouth Africa

The objective of this study is to introduce a coherent theoretical perspective for sustaining forested landscapes at different scales:meta(forest region),gamma(forest property)and alpha(forest stand),with some details on practical *** main part introduces an integrated set of approaches under three headings:a)gamma design,b)alpha jardinage,and c)continuous *** study is based on evidence gathered in the broadleaf and conifer mixed forests of north-eastern China,in European temperate forests,in various forest regions in India,in the afro-montane forests of Southern Africa,and in the pine-oak forests of the Mexican Sierra Madre Occidental.

关键词： forest heading pine

Book review “Wattles: Australian Acacia species around the world” by David M. richardson, Johannes J. Le roux and Elizabete Marchante

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Forest Ecosystems 2024年第2期11卷 140-141页

作者： Klaus von gadow Faculty of Forestry and Forest Ecology Georg-August-University GöttingenBüsgenweg 5D-37077GöttingenGermany Department of Forestry and Wood Science Faculty of AgriSciencesStellenbosch UniversityStellenbosch Private Bag X1Stellenbosch7602South Africa

In a world of Google and AI, developing an encyclopedic coverage of a theme that is of great interest to biologists, social scientists, politicians and environmental managers, is a daunting challenge. Wattles is a book that presents new knowledge, makes interesting reading, and has the potential to stimulate research in a variety of disciplines. We learn that Acacia, commonly known as the wattles or acacias, is a genus of shrubs and trees comprising 1,083 species of which 417 are known to have been introduced to areas outside their native range. We are surprised to read that Australian acacias are found almost everywhere, in virtually all terrestrial habitats, including woodlands, grasslands, alpine settings,rainforests, coastal dunes and deserts, causing major environmental and socio-economic changes in the invaded regions. Until recently, Acacia comprised a group of plant species native to Africa, South America and Australasia, but the name is now reserved for species predominantly from Australia, including some from Southeast Asia. The genus name Acacia is Neo-Latin, and refers to a preparation extracted from the leaves and fruit pods of Vachellia nilotica, the original type of the genus.

关键词： richardson outside Latin

Structure complexity is the primary driver of functional diversity in the temperate forests of northeastern China

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Forest Ecosystems 2022年第4期9卷 511-520页

作者： Zhenghua Lian Juan Wang Chunyu Fan Klaus von gadow research Center of Forest Management Engineering of State Forestry and Grassland Administration Beijing Forestry UniversityBeijing100083China Department of Forest Ecology School of Ecology and Nature ConservationBeijing Forestry UniversityBeijing100083China Faculty of Forestry and Forest Ecology Georg-August-University G€ottingenBüsgenweg 5D-37077GottingenGermany Department of Forest and Wood Science University of StellenboschStellenbosch7600South Africa

Background:Assessing functional diversity to identify its spatial patterns and drivers is an important step towards understanding the adaptive capacity of ecosystems to environmental change. However, until now, these mechanisms were poorly understood in the temperate forests of northeastern China, which prevented the development of new management methods aimed at increasing functional trait diversity and thus ecological ***:In this study, we mapped functional diversity distributions using a Kriging Interpolation Method. A specific random forest model approach was adopted to test the importance ranking of 18 variables in explaining the spatial variation of functional diversity. Three piecewise structural equation models (pSEMs) with forest types as random effects were constructed for testing the direct effects of climate, and the indirect effects of stand structure on functional diversity across the large study region. Specific causal relationships in each forest type were also examined using 15 linear structural equation ***:Although environmental filtering by climate is important, stand structure explains most of the functional variation of the forest ecosystems in northeastern China. Our study thus only partially supports the stressdominance hypothesis. Several abundant species determine most of the functional diversity, which supports the mass ratio ***:Our results suggest that forest management aimed at increasing structural complexity can contribute to increased functional diversity, especially regarding the mixing of coniferous and broad-leaved tree species.

关键词： Functional diversity distribution Forest types Forest management random forest Stand structure attributes Structural equation modeling

Climate change effects in the Western Himalayan ecosystems of India: evidence and strategies

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Forest Ecosystems 2017年第3期4卷 232-240页

作者： Vindhya Prasad Tewari raj Kumar Verma Klaus von gadow Himalayan Forest research Institute Georg-August University Department of Forestry and Wood Science University of Stellenbosch

Background： The fragile landscapes of the Himalayan region are highly susceptible to natural hazards, and there is ongoing concern about current and potential climate change impacts. This study provides background information on India＇s Western Himalayas and reviews evidence of warming as well as variability in precipitation and extreme ***： Understanding and anticipating the impacts of climate change on Himalayan forest ecosystems and the services they provide to people are critical. Efforts to develop and implement effective policies and management strategies for climate change mitigation and adaptation requires particular new research initiatives. The various studies initiated and conducted in the region are compiled ***： Several new initiatives taken by the Himalayan Forest research Institute in Shimla are described. This includes new permanent observational field studies, some with mapped trees, in high altitude transitional zones for continuous monitoring of vegetation response. We have also presented new strategies for mitigating potential climate change effects in Himalayan forest ***： Assessment of the ecological and genetic diversity of the Himalayan conifers is required to evaluate potential responses to changing climatic conditions. Conservation strategies for the important temperate medicinal plants need to be developed. The impact of climate change on insects and pathogens in the Himalayas also need to be assessed. Coordinated efforts are necessary to develop effective strategies for adaptation and mitigation.

关键词： Himalayan ecosystem Climate change New strategies High altitude New observational studies

Mismatch between species distribution and climatic niche optima in relation to functional traits

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Forest Ecosystems 2022年第6期9卷 813-822页

作者： Zhenghua Lian Juan Wang Chunyu Zhang Xiuhai Zhao Klaus von gadow research Center of Forest Management Engineering of State Forestry and Grassland Administration Beijing Forestry UniversityBeijing100083China Department of Forest Ecology School of Ecology and Nature ConservationBeijing Forestry UniversityBeijing100083China Faculty of Forestry and Forest Ecology Georg-August-University GottingenBüsgenweg 5D-37077GottingenGermany Department of Forest and Wood Science University of StellenboschStellenbosch7600South Africa

Background:Forecasts of climate change impacts on biodiversity often assume that the current geographical distributions of species match their niche ***,empirical evidence has challenged this assumption,suggesting a *** examine whether the mismatch is related to functional traits along temperature or precipitation ***:The observed distributions of 32 tree species in northeast China were evaluated to test this *** models were used to estimate the climatic niche optima,*** habitats where the highest species growth and density can be *** mismatch is defined as the difference between the actual species occurrence in an assumed niche optimum and the habitat with the highest probability of species ***’functional traits were used to explore the mechanisms that may have caused the ***:Contrasting these climatic niche optima with the observed species distributions,we found that the distribution-niche optima mismatch had high variability among species based on temperature and precipitation ***,these mismatches depended on functional traits associated with competition and migration lags only in temperature ***:We conclude that more relevant research is needed in the future to quantify the mismatch between species distribution and climatic niche optima,which may be crucial for future designs of forested landscapes,species conservation and dynamic forecasting of biodiversity under expected climate change.

关键词： Demography Functional traits Mean annual temperature Mean annual precipitation Niche theory Species distribution

Tree survival and maximum density of planted forests–Observations from South African spacing studies

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Forest Ecosystems 2015年第1期2卷 11-19页

作者： Klaus v.gadow Heyns Kotze Department of Forest and Wood Science University of Stellenbosch University of G?ttingen Mondi South Africa Division Hilton South Africa

Background：Among the most important aspects of risk and hazard studies relating to forest ecosystems are maximum forest density and density-dependent tree ***：Long-term observations about the maximum density of unthinned Pinus patula and *** field plots based on the Correlated Curve Trend（CCT）spacing studies which were established almost 8 decades ago by O’Connor（Forest research with Special reference to Planting Distances and Thinning,1935）in South *** specific approaches were introduced for analysing maximum density and tree survival,namely the‘limiting line’,Nilson’s sparsity and tree survival with the Weibull ***：The main results are：a）Maximum densities differ greatly among the two species grown on the same site and within the same species grown on different sites;it is possible to relate these differences to site index in both species.b）The relationship between the quadratic mean diameter and the minimum average spacing of surviving trees（known as Nilson’s Sparsity）appears to be surprisingly similar in both species.c）An analysis of tree survival in response to different initial planting espacements shows that the Weibull survival function parameters can be estimated if the initial planting density is *** result is presented for each of the eight large experiments used in this ***：This study contributes to a better understanding of tree survival and maximum density which are the key factors required for estimating risk and *** risk of tree mortality is not constant,but varies with tree species,planting density,tree age and growing *** estimating that risk,therefore,continuous long-term observation on different sites and with varying planting densities,as provided by the unthinned CCT series,are essential.

关键词： Self-thinning Mortality CCT Pinus patula Pinus elliottii South Africa Nelder