期刊文献+
共找到1,714篇文章
< 1 2 86 >
每页显示 20 50 100
STUDIES ON THE PROPERTIES OF SCHIFF BASE TYPE ARYLMERCURY COMPOUNDS Ⅲ TRANSMETALLATION REACTION OF SCHIFF BASE TYPE ARYLMERCURY COMPOUNDS WITH METALLIC TIN
1
作者 Kui Ling DING Yang Jie Wu Yang WANG Department of Chemistry,Zhengzhou University,Zhengzhou 450052Li YANG Lanzhou University,National Applied Laboratory of Organic Chemistry,Lanzhou,730000 《Chinese Chemical Letters》 SCIE CAS CSCD 1993年第3期221-224,共4页
The transmetallation reaction of 4 Schiff base type arylmercury compounds with metallic tin has been carried out in refluxing xylene.It was found that the reaction proceeds in the same manner as that of chloro[2-(phen... The transmetallation reaction of 4 Schiff base type arylmercury compounds with metallic tin has been carried out in refluxing xylene.It was found that the reaction proceeds in the same manner as that of chloro[2-(phenylazo)phenyl]mercury(Ⅱ) to give dichlorobisaryltin(Ⅳ).The ~1H NMR spectra of the products provide evidence for the presence of N→Sn intramolecular coordination.The formation of dichlorobisaryltin(Ⅳ)as a unique product probably arises from the N→Sn intramolecular coordination which results in the increasing of the stability of the molecule. 展开更多
关键词 STUDIES ON THE PROPERTIES OF SCHIFF base type ARYLMERCURY COMPOUNDS TRANSMETALLATION REACTION OF SCHIFF base type ARYLMERCURY COMPOUNDS WITH METALLIC TIN Sn
下载PDF
Synthesis of Schiff Base Type Macrocycles Containing Naphthalene Ring 被引量:1
2
作者 Chang Rong NIU Hai Ning ZHANG Cheng Tai WU(Department of Chemistry, Wuhan University, Wuhan 430072) 《Chinese Chemical Letters》 SCIE CAS CSCD 1997年第7期569-572,共4页
A series of new Schiff base type macrocyclic crown ethers containing naphthalene ring were synthesized from 2,2'-di(o-formylnaphthoxy) ethyl ether or 1,2-di(o-formylnaphthoxy) ethane and four appropriate diamines.... A series of new Schiff base type macrocyclic crown ethers containing naphthalene ring were synthesized from 2,2'-di(o-formylnaphthoxy) ethyl ether or 1,2-di(o-formylnaphthoxy) ethane and four appropriate diamines. The chemical structures of the new compounds were characterized by elemental analysis, infrared spectra, nuclear magnetic resonance spectra and mass spectrometry. 展开更多
关键词 OCH IR CM KBR HNMR Synthesis of Schiff base type Macrocycles Containing Naphthalene Ring
下载PDF
STUDIES ON THE PROPERTIES OF SCHIFF BASE TYPE ARYLMERCURY COMPOUNDS.II ^(199)Hg NMR SPECTRA OF MERCURATED DERIVATIVES OF SUBSTITUTED BENZYLIDENEANILINES
3
作者 Yang Jie WU Kui Ling DING Department of Chemistry,Zhengzhou University,Zhengzhou,450052.Li YANG Lanzhou University,National Applied Laboratory of Organic Chemistry,Lanzhou,730000 《Chinese Chemical Letters》 SCIE CAS CSCD 1992年第9期677-680,共4页
^(199)Hg NHR spectra of 18 Schiff base type arylmercury compounds have been studied.It was further confirmed that in the molecule of XC_6H_4CH=NC_6H_3-2-HgC1-4-CH_3 there exists an intramolecular N→Hg coordination vi... ^(199)Hg NHR spectra of 18 Schiff base type arylmercury compounds have been studied.It was further confirmed that in the molecule of XC_6H_4CH=NC_6H_3-2-HgC1-4-CH_3 there exists an intramolecular N→Hg coordination via a four-membered ring.For the series of XC_6H_4CH=NC_6H_3-2-HgCl-4-CH_3(X is a para-or mera-substituent),there is a good linear correlation between δ^(199)Hg and Hammett's o constants.The influence of substituents of C-pheny1 ring on the δ ^(199)Hg can be explained in terms of the intramolecular N→Hg coordination. 展开更多
关键词 Hg NMR SPECTRA OF MERCURATED DERIVATIVES OF SUBSTITUTED BENZYLIDENEANILINES STUDIES ON THE PROPERTIES OF SCHIFF base type ARYLMERCURY COMPOUNDS.II NMR
下载PDF
Studies on the syntheses and properties of Schiff base type crown ethers 被引量:1
4
作者 W.U,Yang-Jie ZHAO,Bin ZHAO,Li-Wang Department of Chemistry,Zhengzhou University,Zhengzhou,Henan 450052SHEN,Lian-Fang WU,Dong-Hui Laboratory of Magnetic Resonance and Atomic and Molecular Physics,Wuhan Institute of Physics,Chinese Academy of Sciences,Wuhan,Hubei 430071 《Chinese Journal of Chemistry》 SCIE CAS CSCD 1993年第4期360-365,共8页
Eight bis-,two tris-and two mono-crown ethers of Schiff base type have been pre- parcd by the reaction of 4'-formylbenzo-15-crown-5 with diamincs.Conductivity measurements show that the bis-crown ethers form 1:1 c... Eight bis-,two tris-and two mono-crown ethers of Schiff base type have been pre- parcd by the reaction of 4'-formylbenzo-15-crown-5 with diamincs.Conductivity measurements show that the bis-crown ethers form 1:1 complexes(crown cther unit:metal ion)with sodium ion and 2:1 complexes with potassium,rubidium and ammonium ion,respectively. 展开更多
关键词 Studies on the syntheses and properties of Schiff base type crown ethers type base
全文增补中
New Insights into the Depositional Environments of Ordovician Carbonate Formations in the Yubei Area of Tarim Basin Based on Standard Microfacies Types 被引量:5
5
作者 HUANG Chenjun LIU Geyun +3 位作者 MA Yongsheng LIU Bo LIU Hongguang SHI Kaibo 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2017年第2期755-756,共2页
Objective The Yubei area is located in the mid-east Maigaiti slope of southwestern Tarim Basin, China, with an exploration history of several years. Recent exploration has preliminarily indicated that the Ordovician ... Objective The Yubei area is located in the mid-east Maigaiti slope of southwestern Tarim Basin, China, with an exploration history of several years. Recent exploration has preliminarily indicated that the Ordovician carbonate formations in this area have some oil and gas potential. Carbonate microfacies provides material basis for reservoir development, seal formation and hydrocarbon generation. Therefore, this work utilized the standard microfacies (SMF) types to study the microfacies of the Ordovician formations in the Yubei area in order to provide theoretical basis for the next exploration. 展开更多
关键词 In New Insights into the Depositional Environments of Ordovician Carbonate Formations in the Yubei Area of Tarim Basin based on Standard Microfacies types
下载PDF
THE EFFECT OF SUBSTITUENT ON THE THERMAL PROPERTIES OF POLYESTERS CONSISTING OF AROMATIC TYPE SCHIFF BASE MESOGENIC UNITS AND POLYMETHYLENE SPACERS
6
作者 Amar H.Al-Dujaili Iman F.Mustafa Amir T.Atto 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1995年第1期51-58,共8页
Polyesters consisting of substituted aromatic type Schiff base mesogenic unit andpolymethylene spacers were synthesized and their thermal transitions and liquid crystallineproperties were studied. The liquid crystalli... Polyesters consisting of substituted aromatic type Schiff base mesogenic unit andpolymethylene spacers were synthesized and their thermal transitions and liquid crystallineproperties were studied. The liquid crystalline behaviour has been characterized by differentialscanning calorimetry (DSC) and optical polarizing microscopy. Structural broadening bysubstitution of methoxy group in 2, 2' positions of the mesogenic core produce polymers withlower transition temperatures. Polymers synthesized from ortho and meta substituted phenylenediamine did not form a liquid crystal phase. 展开更多
关键词 Liquid crystal polymer Polyesters Aromatic type schiff base Mesogenic units SPACERS
下载PDF
Developing high-efficiency base editors by combining optimized synergistic core components with new types of nuclear localization signal peptide 被引量:3
7
作者 Feipeng Wang Chengwei Zhang +5 位作者 Wen Xu Shuang Yuan Jinling Song Lu Li Jiuran Zhao Jinxiao Yang 《The Crop Journal》 SCIE CAS CSCD 2020年第3期408-417,共10页
The clustered regularly interspaced short palindromic repeats(CRISPR)–CRISPR-associated protein(Cas) system has been widely used for genome editing. In this system, the cytosine base editor(CBE) and adenine base edit... The clustered regularly interspaced short palindromic repeats(CRISPR)–CRISPR-associated protein(Cas) system has been widely used for genome editing. In this system, the cytosine base editor(CBE) and adenine base editor(ABE) allow generating precise and irreversible base mutations in a programmable manner and have been used in many different types of cells and organisms. However, their applications are limited by low editing efficiency at certain genomic target sites or at specific target cytosine(C) or adenine(A) residues. Using a strategy of combining optimized synergistic core components, we developed a new multiplex super-assembled ABE(sABE) in rice that showed higher base-editing efficiency than previously developed ABEs. We also designed a new type of nuclear localization signal(NLS) comprising a FLAG epitope tag with four copies of a codon-optimized NLS(F4NLS^(r2)) to generate another ABE named F4NLS-sABE. This new NLS increased editing efficiency or edited additional A at several target sites. A new multiplex super-assembled CBE(sCBE) and F4NLS^(r2) involved F4NLS-sCBE were also created using the same strategy. F4NLS-sCBE was proven to be much more efficient than sCBE in rice. These optimized base editors will serve as powerful genome-editing tools for basic research or molecular breeding in rice and will provide a reference for the development of superior editing tools for other plants or animals. 展开更多
关键词 CBE ABE NLS Developing high-efficiency base editors by combining optimized synergistic core components with new types of nuclear localization signal peptide
下载PDF
Design of Zr-based AB_2 type hydrogen storage alloys
8
作者 文明芬 王秋萍 +2 位作者 王兴海 翟玉春 陈廉 《中国有色金属学会会刊:英文版》 CSCD 2003年第6期1472-1474,共3页
The influences of the ratio of the radius of atom A(rA) to radius of atom B(rB), electronegativity and electron number were discussed on the Laves phase formation and the characteristics of Zr-based AB2 type hydro... The influences of the ratio of the radius of atom A(rA) to radius of atom B(rB), electronegativity and electron number were discussed on the Laves phase formation and the characteristics of Zr-based AB2 type hydrogen storage alloy. An enthalpy model of Zr-based AB2 alloy was obtained from known data and twelve Zr-based alloys were designed to test the model. The results show that the predicted values are in good agreement with the experimental values. The model can be used for predicting enthalpy values of Zr-based hydrogen storage alloys and settles a foundation for experiments. 展开更多
关键词 锆合金 储氢合金 AB2型 化学成分 设计
下载PDF
Magnetic Field Induced Entropy Change for La-Fe Based NaZn_(13)-Typed Compounds
9
作者 Zhang Hongwei Sun Jirong Hu Fengxia Wang Fang Shen Baogen 《Journal of Rare Earths》 SCIE EI CAS CSCD 2005年第4期I0011-I0011,共1页
Magnetic field induced entropy change was investigated for La-Fe based NaZn13-type compounds with magnetic first-order phase transition. In view of magnetic refrigeration at room temperature, the developing of the mat... Magnetic field induced entropy change was investigated for La-Fe based NaZn13-type compounds with magnetic first-order phase transition. In view of magnetic refrigeration at room temperature, the developing of the materials and the understanding of the entropy change were., reviewed. For La-Fe-Si compounds, the entropy change about 29 J·kg^- 1·K^-1 was obtained at 190 K under the magnetic field of 5 T.While a large entropy change of about 15 J·kg^-1·K^-1 near room temperature under 5 T can be obtained by the substitution of Co for Fe in the compounds. It is found that the entropy change is mainly composed of that contributed from magnetic ordering and crystal lattice. The large entropy change consumed by lattice contribution is mainly due to the magnetic ordering one. 展开更多
关键词 La-Fe based NaZn13-typed compounds entropy change magnetic first-order phase transition rare earths
下载PDF
Optimizing the atom types of proteins through iterative knowledge-based potentials
10
作者 汪心享 黄胜友 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第2期43-50,共8页
Knowledge-based scoring functions have been widely used for protein structure prediction, protein-small molecule, and protein-nucleic acid interactions, in which one critical step is to find an appropriate representat... Knowledge-based scoring functions have been widely used for protein structure prediction, protein-small molecule, and protein-nucleic acid interactions, in which one critical step is to find an appropriate representation of protein structures. A key issue is to determine the minimal protein representations, which is important not only for developing of scoring func- tions but also for understanding the physics of protein folding. Despite significant progresses in simplifying residues into alphabets, few studies have been done to address the optimal number of atom types for proteins. Here, we have investigated the atom typing issue by classifying the 167 heavy atoms of proteins through 11 schemes with 1 to 20 atom types based on their physicochemical and functional environments. For each atom typing scheme, a statistical mechanics-based iterative method was used to extract atomic distance-dependent potentials from protein structures. The atomic distance-dependent pair potentials for different schemes were illustrated by several typical atom pairs with different physicochemical proper- ties. The derived potentials were also evaluated on a high-resolution test set of 148 diverse proteins for native structure recognition. It was found that there was a crossover around the scheme of four atom types in terms of the success rate as a function of the number of atom types, which means that four atom types may be used when investigating the basic folding mechanism of proteins. However, it was revealed by a close examination of typical potentials that 14 atom types were needed to describe the protein interactions at atomic level. The present study will be beneficial for the development of protein related scoring functions and the understanding of folding mechanisms. 展开更多
关键词 atom types knowledge-based potentials statistical mechanics ITERATION
下载PDF
Mannich-Type Reactions of Aldimines and Hetero Diels-Alder Reactions of Aldehydes Catalyzed by Anion-Type Lewis Bases Derived from a Single Molecule
11
作者 Kaori Ishimaru Daiki Maeda +1 位作者 Kaori Ono Yuya Tanimura 《International Journal of Organic Chemistry》 2012年第3期188-193,共6页
Mannich-type reactions of aldimines with silyl enolates and hetero Diels-Alder reactions of aldehydes with Danishef-sky’s diene in the presence of anion catalysts derived from proline were performed to afford the cor... Mannich-type reactions of aldimines with silyl enolates and hetero Diels-Alder reactions of aldehydes with Danishef-sky’s diene in the presence of anion catalysts derived from proline were performed to afford the corresponding products in high yields. 展开更多
关键词 ANION Catalyst Lewis base Proline Mannich-type REACTION Hetero DIELS-ALDER REACTION
下载PDF
Cost-benefit analysis of screening for diabetic retinopathy among Chinese type 2 diabetes: decision from different perspectives of a population-based study 被引量:2
12
作者 Ching-Ching Peng Pesus Chou +6 位作者 Tao-Hsin Tung Wu-Hsiung Chien Fenq-Lih Lee Shih-Jen Chen Shih-Tzer Tsai Chi-Ming Liu Jorn-Hon Liu 《Health》 2009年第4期304-312,共9页
The purpose of this study is to explore whether it is worthwhile to launch a routine diabetic retinopathy (DR) screening for blindness pre-vention among Chinese type 2 diabetes from different perspective based on the ... The purpose of this study is to explore whether it is worthwhile to launch a routine diabetic retinopathy (DR) screening for blindness pre-vention among Chinese type 2 diabetes from different perspective based on the popula-tion-based study in Kinmen, Taiwan. A total of 971 community dwelling adults previously di-agnosed with type 2 diabetes in 1991-1993 un-derwent DR screening in 1999-2002 by a panel of ophthalmologists using on-site indirect oph-thalmoscopy and 45-degree color fundus retinal photographs. The cost-benefit analysis is used to evaluate the DR screening. In terms of bene-fit-cost ratio, the different screening programs for DR could save New Taiwan Dollars (NTD) from 14.38 to 36.83 in discounted costs for each dollar incurred in different screening years from the societal viewpoint for Taiwan and save NTD from 0.81 to 1.80 in different screening years from health care payer’s perspective. The av-erage estimate of willingness-to-pay to translate into benefit yields NTD from 937.8 to 4,689 be- nefits per case due to DR screening in different screening years during 10-year follow-up. The net present value of the DR screening were NTD from -167,318 to -307,251.2 in different screening years. In conclusion, it is worthwhile to initial a routine DR screening of Chinese type 2 diabetes for blindness prevention from the societal per-spective but not from consumer decision based on the willingness-to-pay perspective. 展开更多
关键词 type 2 DIABETES DIABETIC RETINOPATHY COST-BENEFIT Analysis POPULATION-baseD Study
下载PDF
Combined Influence of Insulin Resistance and Inflammatory Biomarkers on Type 2 Diabetes:A Population-based Prospective Cohort Study of Inner Mongolians in China 被引量:16
13
作者 QIU Qiao Yan ZHANG Bei Lei +5 位作者 ZHANG Ming Zhi WU Jia Hui ZHOU Jing Wen LIANG Zhu ZHANG Yong Hong ZHANG Shao Yan 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2018年第4期300-305,共6页
This prospective study was designed to examine the combined influence of insulin resistance(IR)and inflammatory biomarker levels on type 2 diabetes mellitus(T2DM)among 1,903Inner Mongolians.
关键词 CRP DM Combined Influence of Insulin Resistance and Inflammatory Biomarkers on type 2 Diabetes A Population-based Prospective Cohort Study of Inner Mongolians in China IR
下载PDF
Identification of Question and Non-Question Segments in Arabic Monologues Using Prosodic Features: Novel Type-2 Fuzzy Logic and Sensitivity-Based Linear Learning Approaches
14
作者 Sunday Olusanya Olatunji Lahouari Cheded +1 位作者 Wasfi G. Al-Khatib Omair Khan 《Journal of Intelligent Learning Systems and Applications》 2013年第3期165-175,共11页
In this paper, we extend our previous study of addressing the important problem of automatically identifying question and non-question segments in Arabic monologues using prosodic features. We propose here two novel c... In this paper, we extend our previous study of addressing the important problem of automatically identifying question and non-question segments in Arabic monologues using prosodic features. We propose here two novel classification approaches to this problem: one based on the use of the powerful type-2 fuzzy logic systems (type-2 FLS) and the other on the use of the discriminative sensitivity-based linear learning method (SBLLM). The use of prosodic features has been used in a plethora of practical applications, including speech-related applications, such as speaker and word recognition, emotion and accent identification, topic and sentence segmentation, and text-to-speech applications. In this paper, we continue to specifically focus on the Arabic language, as other languages have received a lot of attention in this regard. Moreover, we aim to improve the performance of our previously-used techniques, of which the support vector machine (SVM) method was the best performing, by applying the two above-mentioned powerful classification approaches. The recorded continuous speech is first segmented into sentences using both energy and time duration parameters. The prosodic features are then extracted from each sentence and fed into each of the two proposed classifiers so as to classify each sentence as a Question or a Non-Question sentence. Our extensive simulation work, based on a moderately-sized database, showed the two proposed classifiers outperform SVM in all of the experiments carried out, with the type-2 FLS classifier consistently exhibiting the best performance, because of its ability to handle all forms of uncertainties. 展开更多
关键词 ARABIC Monologues Prosodic Features type-2 FUZZY LOGIC Systems Sensitivity based LINEAR LearningMethod Support Vector Machines
下载PDF
Type 2 Diabetes Wellness Program in a Faith-Based Organization
15
作者 Frenzy Papas Kiamco 《Journal of Diabetes Mellitus》 2016年第4期291-300,共11页
In this practicum, the program objective is to improve the health of Joseph’s Storehouse food bank recipients’ community in the Blessing Center (New Hope Free Clinic and Joseph’s food bank), Redlands, California. T... In this practicum, the program objective is to improve the health of Joseph’s Storehouse food bank recipients’ community in the Blessing Center (New Hope Free Clinic and Joseph’s food bank), Redlands, California. The approach is to implement primary prevention and secondary prevention activity to increase knowledge and skills of the clients and their families of how to prevent and control type 2 diabetes through a wellness program in the clinic. The practicum began January 2015 and ended April 2015. 53 food bank recipients (non-diabetic and diabetic) were recruited. A quasi-experimental study design, pre-test/posttest, was used for the study. The impact of the program targeted diverse audience, high risk ethnic groups, and improved knowledge, awareness, management, and positive behavioral change. The study implication for public health promotion specialists is to narrow venues targeting the most vulnerable populations to promote and reduce type 2 diabetes. 展开更多
关键词 type 2 Diabetes California Faith-based Organization Diabetes Mellitus Public Health Wellness Program PRACTICUM Primary Prevention Secondary Prevention Diabetes in California Diabetes Disparity Diabetes Education Food Bank
下载PDF
Ru(Schiff-base)/Y复合材料对苯加氢反应的催化性能研究 被引量:1
16
作者 陈萍 宋明刚 +2 位作者 范彬彬 马静红 李瑞丰 《燃料化学学报》 EI CAS CSCD 北大核心 2006年第3期364-367,共4页
一种新的低温苯加氢催化剂Ru(Sch iff-base)金属配合物,通过自由配体法封装于Y型沸石的孔腔中。使用XRD、N2吸附、FT-IR、DRS、DTA对催化剂进行表征。结果表明,复合催化剂中希夫碱(Sch iff-base)配体改变了中心离子的电子结构,使其更容... 一种新的低温苯加氢催化剂Ru(Sch iff-base)金属配合物,通过自由配体法封装于Y型沸石的孔腔中。使用XRD、N2吸附、FT-IR、DRS、DTA对催化剂进行表征。结果表明,复合催化剂中希夫碱(Sch iff-base)配体改变了中心离子的电子结构,使其更容易与反应物分子形成配位过渡态,络合活化的反应物分子更容易转化为产物。与离子交换法制备的母体Ru/Y相比,对纯苯的催化加氢性能明显提高。希夫碱配体的几何尺寸对复合材料的催化性能也有很大影响。 展开更多
关键词 Ru复合催化剂 希夫碱 苯加氢 络合活化 Y型沸石
下载PDF
案例教学在材料与化工专业硕士学位教学中的应用研究——以“材料结构与性能”中高分子材料教学为例
17
作者 田佳壮 李艳妮 +2 位作者 高树林 何红星 杨艳华 《云南化工》 2025年第1期117-122,共6页
为了适应“材料结构与性能”课程综合性强、知识点多、抽象度高等特点,经过三年的探索,教学团队将实验型、知识型、实用型和解决现实问题型等教学案例引入课程教学中,激发了学生学习积极性,不仅能更好掌握高分子材料模块相关知识,而且... 为了适应“材料结构与性能”课程综合性强、知识点多、抽象度高等特点,经过三年的探索,教学团队将实验型、知识型、实用型和解决现实问题型等教学案例引入课程教学中,激发了学生学习积极性,不仅能更好掌握高分子材料模块相关知识,而且还能提升分析问题和解决问题的能力。通过知识点与教学案例的融合,强化了知识在生产生活中的深度应用,让学生学有所成、学有所思,对促进专业学位研究生的整体培养有重要意义。 展开更多
关键词 材料结构与性能 高分子材料 案例教学 实验型 知识型 实用型 解决现实问题型
下载PDF
True Type格式“地质矿产符号库”特点介绍 被引量:1
18
作者 刘冶兵 王立民 +1 位作者 陈雷 徐卫 《吉林地质》 2004年第2期69-71,共3页
"地质矿产符号库"是一套采用国际先进技术、符合国内行业标准的专业字库。具有4大特点,可用8个字概括:"美观、统一、规范、通用"。
关键词 Truetype格式 空间数据库 国家标准 “地质矿产符号库”
下载PDF
带镍基堆焊层管嘴与Type 304L GTAW焊接裂纹分析及预防措施 被引量:2
19
作者 赵辉 付永生 张学武 《热加工工艺》 CSCD 北大核心 2015年第11期243-244,249,共3页
针对AP1000核电厂正常余热排出泵带堆焊层管嘴与Type 304L奥氏体不锈钢管道安装焊接过程中产生裂纹,对裂纹产生的原因进行了分析,并提出了改进焊接材料及优化焊接工艺等措施,防止了裂纹的产生。
关键词 带镍基堆焊层 type 304L GTAW焊接 裂纹
下载PDF
Trait-based representation of hydrological functional properties of plants in weather and ecosystem models 被引量:2
20
作者 Ashley M. Matheny Golnazalsadat Mirfenderesgi Gil Bohrer 《Plant Diversity》 SCIE CAS CSCD 北大核心 2017年第1期1-12,共12页
Land surface models and dynamic global vegetation models typically represent vegetation through coarse plant functional type groupings based on leaf form, phenology, and bioclimatic limits. Although these groupings we... Land surface models and dynamic global vegetation models typically represent vegetation through coarse plant functional type groupings based on leaf form, phenology, and bioclimatic limits. Although these groupings were both feasible and functional for early model generations, in light of the pace at which our knowledge of functional ecology, ecosystem demographics, and vegetation-climate feedbacks has advanced and the ever growing demand for enhanced model performance, these groupings have become antiquated and are identified as a key source of model uncertainty. The newest wave of model development is centered on shifting the vegetation paradigm away from plant functional types(PFTs)and towards flexible trait-based representations. These models seek to improve errors in ecosystem fluxes that result from information loss due to over-aggregation of dissimilar species into the same functional class. We advocate the importance of the inclusion of plant hydraulic trait representation within the new paradigm through a framework of the whole-plant hydraulic strategy. Plant hydraulic strategy is known to play a critical role in the regulation of stomatal conductance and thus transpiration and latent heat flux. It is typical that coexisting plants employ opposing hydraulic strategies, and therefore have disparate patterns of water acquisition and use. Hydraulic traits are deterministic of drought resilience, response to disturbance, and other demographic processes. The addition of plant hydraulic properties in models may not only improve the simulation of carbon and water fluxes but also vegetation population distributions. 展开更多
关键词 Hydraulic traits Land-surface modeling Whole-plant hydraulic strategy Trait-based models Demographic models Plant functional type
下载PDF
上一页 1 2 86 下一页 到第
使用帮助 返回顶部