检索结果-南通市图书馆

竹子扩张对阔叶林物种多样性的影响:两竹种的叠加效应

在线全文

学校读者我要写书评

暂无评论

应用生态学报 2017年第10期28卷 3155-3162页

作者：杨清培郭英荣兰文军宋庆妮杨光耀江西农业大学江西省竹子种质资源与利用重点实验室南昌330045 江西武夷山国家级自然保护区管理局江西上饶334515

研究了不同扩张强度下毛竹和肿节少穗竹对江西武夷山常绿阔叶林群落结构和物种多样性的影响.结果表明:毛竹、肿节少穗竹扩张都会不同程度地改变阔叶林群落结构与物种组成,两者同时高强度扩张时(毛竹30～50 ind·100 m^(-2),肿节少穗竹30... 详细信息

研究了不同扩张强度下毛竹和肿节少穗竹对江西武夷山常绿阔叶林群落结构和物种多样性的影响.结果表明:毛竹、肿节少穗竹扩张都会不同程度地改变阔叶林群落结构与物种组成,两者同时高强度扩张时(毛竹30～50 ind·100 m^(-2),肿节少穗竹300～500 ind·100m^(-2)),群落的乔∶灌(密度比)由2∶8变成1∶9,竹∶木(密度比)由0∶10变成9∶1.毛竹、肿节少穗竹扩张对阔叶林物种多样性影响的主效应显著,毛竹主要影响乔木层,肿节少穗竹主要影响灌木层,但两种竹子的交互作用不显著.两种竹子同时扩张对群落生物多样性的影响存在叠加效应,尤其是高强度扩张使群落Shannon指数下降91.3%.毛竹与肿节少穗竹同时低强度扩张时,两者相互影响不大,但当达到一定密度后两者会相互竞争排斥.这表明,当常绿阔叶林同时遭受毛竹、肿节少穗竹扩张时,虽然二者交互作用不明显,但会通过叠加效应影响木本植物,导致阔叶林群落简单化.

关键词：毛竹肿节少穗竹物种多样性叠加效应常绿阔叶林

A versatile synthetic strategy towards rare earth based metal-organic frameworks

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2025年

作者： Quan Shi Yun-Hao Xu Ming-Hui Chen Peng Zhao wen-Bo Deng Ji Xiong Kai Guo Ya-qing Feng Bao Zhang School of Chemical Engineering and Technology Tianjin University Tianjin Collaborative Innovation Center of Chemical Science and Engineering Guangdong Laboratory Chemistry & Fine Chemical Industry Jieyang Center

Rare earth metal-organic frameworks (RE-MOFs) have drawn wide attention owing to diverse network structures and various application ***,due to the unpredictable formation of the nodes,it is still challenging to design novel RE-MOFs.A novel versatile strategy was developed employing a RE-acetate complex (RE2(CH3COO)6·4H2O) as a precursor to construct RE-MOFs.2D RE-MOFs (RE-DBP) and 3D RE-MOFs (RE-TCPP) could be obtained by using dicarboxylic porphyrin ligands H2DBP and tetracarboxylic porphyrin ligands H2TCPP,*** RE-MOFs were further synthesized to verify the universality of the *** crystalline RE-MOFs could also be prepared at room temperature via the developed strategy,which could significantly promote large-scale preparation and practical application of *** proof of the concept,the performance of porphyrin-based RE-MOFs was investigated in the photocatalytic cycloaddition of CO2with *** the RE-DBP(Co) MOFs,Tb-DBP(Co) exhibited the best photocatalytic performance,which was also greater than that of the corresponding 3D MOF Tb-TCPP(Co) due to the optimal 2D structure and thus the accelerated photogenerated charge separation and transfer *** work not only provides a novel versatile strategy to design and develop RE-MOFs,but also proposes a promising approach for the potential bulk production of RE-MOFs at room temperature.

关键词：

Preparation of FeConi medium entropy alloy from Fe^(3+)-Co^(2+)-ni^(2+)solution system

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2025年第1期32卷 92-101页

作者： Zongyou Cheng qing Zhao Mengjie Tao Jijun Du Xingxi Huang Chengjun Liu Key Laboratory for Ecological Metallurgy of Multimetallic Mineral(Ministry of Education) Northeastern UniversityShenyang 110819China School of Metallurgy Northeastern UniversityShenyang 110819China Engineering Research Center of Frontier Technologies for Low-carbon Steelmaking(Ministry of Education) Shenyang 110819China

In recent years,medium entropy alloys have become a research hotspot due to their excellent physical and chemical *** controlling reasonable elemental composition and processing parameters,the medium entropy alloys can exhibit similar properties to high entropy alloys and have lower *** this paper,a FeConi medium entropy alloy precursor was prepared via sol-gel and coprecipitation methods,respectively,and FeConi medium entropy alloys were prepared by carbothermal and hydrogen *** phases and magnetic properties of FeConi medium entropy alloy were *** showed that FeConi medium entropy alloy was produced by carbothermal and hydrogen reduction at 1500℃.Some carbon was detected in the FeConi medium entropy alloy prepared by carbothermal *** alloy prepared by hydrogen reduction was uniform and showed a relatively high ***,the hydrogen reduction product exhibited better saturation magnetization and lower coercivity.

关键词： medium entropy alloy sol-gel co-precipitation carbothermal hydrogen reduction

Based on non-targeted metabolomics for differential components screening of Rosae Chinensis Flos and Rosae Rugosae Flos and their quality evaluation

在线全文

学校读者我要写书评

暂无评论

Traditional Medicine Research 2025年第2期10卷 1-15页

作者： Xu Liang ni-Hui Zhang Zhi-Lai Zhan Guang-Lu Chang Yan Gao Xia Li wen-Yuan Gao School of Pharmaceutical Science and Technology Faculty of MedicineTianjin UniversityTianjin 300193China State Key Laboratory for Quality Ensurance and Sustainable Use of Dao-di Herbs China Academy of Chinese Medical SciencesBeijing 100700China Key Laboratory of Modern Chinese Medicine Resources Research Enterprises Tianjin 300402China

Background:Rosa chinensis *** Rosa rugosa *** not only of ornamental value,but also edible flowers and the flower buds have been listed in the Chinese Pharmacopoeia as traditional *** two plants have some differences in efficacy,but the flower buds are easily confused for similar *** addition,large-scale cultivation of ornamental rose flowers may lead to a decrease in the effective components of medicinal ***,it is necessary to study the chemical composition and make quality evaluation of Rosae Chinensis Flos(Yueji)and Rosae Rugosae Flos(Meigui).Methods:In this study,40 batches of samples including Meigui and Yueji from different regions in China were collected to establish high-performance liquid chromatography ***,the fingerprints data was analyzed using principal component analysis,hierarchical cluster analysis,and partial least squares discriminant analysis analysis chemometrics to obtain information on intergroup differences,and non-targeted metabolomic techniques were applied to identify and compare chemical compositions of samples which were chosen from groups with large *** compounds were screened by orthogonal partial least-squares discriminant analysis and S-plot,and finally multi-component quantification was performed to comprehensively evaluate the quality of Yueji and ***:The similarity between the fingerprints of 40 batches roses and the reference print R was 0.73 to 0.93,indicating that there were similarities and differences between the *** principal component analysis and hierarchical cluster analysis of fingerprints data,the samples from different origins and varieties were intuitively divided into four *** least-squares discriminant analysis analysis showed that Meigui and Yueji cluster into two categories and the model was reliable.A total of 89 compounds were identified by high resolution mass spectrometry,mainly were flavonoids and flavon

关键词： Rosa chinensis Jacq. Rosa rugosa Thunb. metabolomics chemometrics multiple component quantification quality evaluation

Recovery of iron from copper slag by deep reduction and magnetic beneficiation

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2013年第11期20卷 1035-1041页

作者： Ke-qing Li Shuo Ping Hong-yu Wang wen ni Key Laboratory of the Ministry of Education of China for High-Efcient Mining and Safety of Metal Mines University of Science and Technology Beijing School of Civil and Environmental Engineering University of Science and Technology Beijing

Aiming at recovering iron from high-iron-content copper slag, this article introduced a combination technol- ogy of deep reduction and magnetic beneficiation, investigated the iron recovery efficiency and optimized the technical conditions. When coke powder with 86wt% fixed carbon was used as a reductant, iron was successfully extracted from the copper slag. Under the optimized condition of the coke powder content of 14wt%, the calcium-to-silicon mass ratio （Ca/Si） of 0.2, the roasting temperature of 1300℃, the roasting time of 3 h, the grinding time of 20 min, and the magnetic field intensity of 61 kA-m-1, the iron recovery rate of the copper slag can reach 91.82%, and the extracted iron powder has an iron grade of 96.21%. With the characteristics of high iron grade and low impurity content, the extracted iron powder can be used as high-quality raw materials of weathering steel.

关键词： copper slag waste utilization ore reduction magnetic separation beneficiation

Crystallization characteristics of iron-rich glass ceramics prepared from nickel slag and blast furnace slag

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2011年第4期18卷 455-459页

作者： Zhong-jie Wang wen ni Ke-qing Li Xiao-yan Huang Li-ping Zhu School of Civil and Environmental Engineering University of Science and Technology Beijing Beijing 100083 China

The crystallization process of iron-rich glass-ceramics prepared from the mixture of nickel slag（NS） and blast furnace slag（BFS） with a small amount of quartz sand was investigated.A modified melting method which was more energy-saving than the traditional methods was used to control the crystallization *** results show that the iron-rich system has much lower melting temperature,glass transition temperature（Tg）,and glass crystallization temperature（Tc）,which can result in a further energy-saving *** results also show that the system has a quick but controllable crystallization process with its peak crystallization temperature at 918°*** crystallization of augite crystals begins from the edge of the sample and invades into the whole *** crystallization process can be completed in a few minutes.A distinct boundary between the crystallized part and the non-crystallized part exists during the *** the non-crystallized part showing a black colour,some sphere-shaped augite crystals already exist in the glass matrix before samples are heated to *** the crystallized part showing a khaki colour,a compact structure is formed by augite crystals.

关键词： glass ceramics grain growth crystallization slag

Iron Extraction From Oolitic Iron Ore by a Deep Reduction Process

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2011年第8期18卷 9-13页

作者： LI Ke-qing ni wen ZHU Ming ZHENG Mei-juan LI Yuan Key Laboratory of the Ministry of Education of China for High-Efficient Mining and Safety of Metal Mines University of Science and Technology Beijing Beijing 100083 China

A laboratory experiment was carried out to extract iron from oolitic iron ore by a deep reduction and magnetic separation technique. The raw coal with fixed carbon of 66.54% was used as the reductant. The iron was successfully extracted from the oolitic iron ore which otherwise is nearly impossible to be separated due to its extremely fine-grain and mosaic nature. The results showed that an iron recovery rate of 90.78% and an iron content of 92.53~ of iron concentrate could be obtained by such a technique. The optimized roast temperature is 1 200℃ and time is 60 min. The subsequent magnetic separation was performed by using a magnetic field intensity of 111 kA · m^-1 and a grinding fineness less than 45 μm of 96. 19% for the sintered product.

关键词： oolitic hematite deep reduction magnetic separation

Electrochemical Synthesis and Research of Two Polymers Composed of Alternate Carbazole and Thiophene Units

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Physics 2015年第5期28卷 -页

作者： qing Cheng qing-zhen wen College of Science Naval University of Engineering Wuhan 430033 china

Two organic conjugated molecules composed of central carbazole and bithiophene groups were prepared via the Stille coupling reaction, conductive polymers were prepared by electrochemical method. Structure and photoelectric research of polymers were investigated. 1H NMR and 13C NMR of molecules were consistent with the theorical results, FT-IR showed electrochemical polymeric site were β-position of thiophene units. The smooth morphology and distributed holes were beneficial to improve the electrical conductivity by SEM. When applied voltage was from ?0.1 V to 1.2 V, both of the polymer films P1 and P2 showed good electrochromic performances. Compared with P1, P2 had better electrochemical stability and thermal stability due to the better coplanarity by repeated cyclic voltammograms and TGA. The P2 was a promising material in the electrochemical field, meanwhile, it showed that the monomer structure had greatly impact on the performance of polymer.

关键词： Stille reaction Cyclic voltammetry Electrochemistry polymerization Spectroelectrochemistry

Reciprocal Regulation between Fur and Two RyhB Homologs in Yersinia pestis,and Roles of RyhBs in Biofilm Formation

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Biomedical and Environmental Sciences 2021年第4期34卷 299-308页

作者： ni Bin WU Hai Sheng XIN You Quan ZHANG qing wen ZHANG Yi Quan School of Medicine Jiangsu UniversityZhenjiang 212013JiangsuChina qinghai Institute for Endemic Disease Prevention and Control Xining 811602QinghaiChina Wuxi School of Medicine Jiangnan UniversityWuxi 214122JiangsuChina

Objective To investigate reciprocal regulation between Fur and two RyhB homologs in Yersinia pestis(***),as well as the roles of RyhBs in biofilm *** Regulatory relationships were assessed by a combination of colony morphology assay,primer extension,electrophoretic mobility shift assay and DNase I *** Fur bound to the promoter-proximal DNA regions of ryhB1 and ryhB2 to repress their transcription,while both RyhB1 and RyhB2 repressed the expression of Fur at the post-transcriptional *** addition,both RyhB1 and RyhB2 positively regulated *** biofilm exopolysaccharide(EPS)production and the expression of hmsHFRS and *** Fur and the two RyhB homologs exert negative reciprocal regulation,and RyhB homologs have a positive regulatory effect on biofilm formation in ***.

关键词： Yersinia pestis RyhB Fur Biofilm