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理论联系实际的教学实践——以乙烯和丙烯聚合物为例

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高分子通报 2025年第1期38卷 157-162页

作者：姚金水杨文轲乔从德李仲伟齐鲁工业大学(山东省科学院)材料科学与工程学院济南250353

将抽象的教学内容与高分子材料实际生产和应用中的典型实例结合,其教学效果肯定是事半功倍的。本文以高分子材料中常见的乙烯、丙烯的均聚物及其共聚物为教学实例,选择其结构(构型)和结晶性能两个教学内容,来引导学生形象地去理解高分... 详细信息

将抽象的教学内容与高分子材料实际生产和应用中的典型实例结合,其教学效果肯定是事半功倍的。本文以高分子材料中常见的乙烯、丙烯的均聚物及其共聚物为教学实例,选择其结构(构型)和结晶性能两个教学内容,来引导学生形象地去理解高分子物理中结构、构型以及结晶性的关系,并进而了解其应用性能,从而将书本上的理论知识与高分子实际生产和应用相结合,收到了很好的教学效果。

关键词：结构构型结晶性共聚物均聚物聚乙烯聚丙烯

Spatial patterns and storage composition of woody debris in a natural secondary forest dominated by Pinus tabulaeformis on Loess Plateau, China

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Journal of Mountain Science 2017年第9期14卷 1839-1851页

作者： GU li GONG Zhi-wen li wei-zhong College of Forestry Northwest A&F University Yangling 712100 China College of Economics &Management Northwest A&F University Yangling 712100 China

Woody debris(WD) is an important par of natural Pinus tabulaeformis mixed stands, and i affects the forest ecosystem stability and developmen The WD spatial patterns are especially importan structural characteristics that can provide insights into forest dynamics. In this paper, the WD storage WD spatial patterns and WD associations among the main species were examined in the natural secondary forest on Loess Plateau in northwest China. Data were collected in a 1 ha(100 m × 100 m) permanent plot and all the trees with a diameter at breast height o more than 3 cm were measured and stem-mapped Ripley's K functions from the spatial-point-pattern analysis method were used to analyze the spatia distribution and associations. The results showed tha(1) The total storage of WD was 10.73 t/ha, fallen wood was the main source of WD, and the majority diameters were greater than 20 cm, and in intermediate levels of decay;(2) The overall spatia pattern was closely related to the spatial scale, which exhibited an aggregated pattern on a small scale, and a random pattern on a large scale. The spatia patterns of coarse woody debris also gradually transitioned from an aggregated pattern in fine scales to a random pattern in broader spatial scales, which matched the overall spatial pattern. The spatial intensity was gradually decreased with the increasing diameters, and increased with the decomposition classes;(3) The WD of Pinus tabulaeformis species was negatively associated with Betula platyphylla and Populus davidiana on a small scale but positively associated with these species on a large scale. The spatial pattern and interspecies relations were the results of long-term interactions between the natural secondary forest community and the surrounding natural environment. These findings would provide a scientific basis for the sustainable management and protection of natural secondary forest ecosystems on Loess Plateau.

关键词： Spatial pattern Spatial association Storage Woody debris Natural secondary forest Loess Plateau

Flotation performances of polymorphic pyrrhotite

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Journal of Central South University 2012年第1期19卷 238-243页

作者： HE Ming-fei QIN Wen qing li wei-zhong JIAO Fen School of Minerals Processing and Bioengineering Central South UniversityChangsha 410083China

The floatability of different crystalline structures of pyrrhotite(monoclinic and hexagonal) was *** is shown that the floatability of monoclinic and hexagonal has obvious difference,and that the flotation recovery of monoclinic pyrrhotite is larger than that of hexagonal pyrrhotite using different *** butyl dithiophosphate is used as the collector,the recovery is larger than that by sodium butyl xanthate and sodium diethyl *** the pH values ranging from 6 to 9,monoclinic pyrrhotite can be floated well,and the flotation recovery is higher than 90%.Monoclinic and hexagonal pyrrhotites are more easily activated by Cu2+ in acidic conditions than in alkaline *** Cu2+ cannot activate hexagonal pyrrhotite using sodium diethyldithiocarbamate as the *** the measurement of contact angle,it is indicated that monoclinic and hexagonal pyrrhotites float well and are easily activated by Cu2+ when dithiophosphate is used as the *** sodium diethyl dithiocarbamate as a collector,the relationship between potential and pH range for pyrrhotite flotation is *** pH 5,the optimal potential range for flotation of monoclinic pyrrhotite is about 125-580 mV(vs SHE),with the maximum flotation occurring at about 350 mV(vs SHE);the optimal potential range for flotation of hexagonal pyrrhotite is 200?580 mV(vs SHE),with the maximum flotation occurring at about 300 mV(vs SHE).

关键词： flotation pyrrhotite pulp potential contact angle

Both combinatorial K4me0-K36me3 marks on sister histone H3s of a nucleosome are required for Dnmt3a-Dnmt3L mediated de novo DNA methylation

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Journal of Genetics and Genomics 2020年第2期47卷 105-114页

作者： Ting Gong Xin Gu Yu-Ting liu Zhen Zhou ling-li Zhang Yang Wen wei-li zhong Guo-liang Xu Jin-Qiu Zhou State Key Laboratory of Molecular Biology CAS Center for Exellence in Molecular Cell ScienceShanghai Institute of Biochemistry and Cell BiologyChinese Acadermy of SciencesUniversity of Chinese Academy of SciencesShanghai200031China School of life Science and Technology Shanghai Tech UniversityShanghai201210China

A nucleosome contains two copies of each histone H2A,H2B,H3 and *** H3 K4me0 and K36me3are two key chromatin marks for de novo DNA methylation catalyzed by DNA methyltransferases in ***,it remains unclear whether K4me0 and K36me3 marks on both sister histone H3s regulate de novo DNA methylation independently or ***,taking advantage of the bivalent histone H3 system in yeast,we examined the contributions of K4 and K36 on sister histone H3s to genomic DNA methylation catalyzed by ectopically co-expressed murine Dnmt3a and *** results show that lack of both K4me0 and K36me3 on one sister H3 tail,or lack of K4me0 and K36me3 on respective sister H3s results in a dramatic reduction of 5mC,revealing a synergy of two sister H3s in DNA methylation ***,the Dnmt3a or Dnmt3L mutation that disrupts the interaction of Dnmt3aADD domain-H3K4me0,Dnmt3LADD domain-H3K4me0,orDnmt3aPWWP domain-H3K36me3 causes a significant reduction of DNA *** results support the model that each heterodimeric Dnmt3a-Dnmt3L reads both K4me0 and K36me3 marks on one tail of sister H3s,and the dimer of heterodimeric Dnmt3a-Dnmt3L recognizes two tails of sister histone H3s to efficiently execute de novo DNA methylation.

关键词： Asymmetrical nucleosome Histone H3K4 methylation Histone H3K36 methylation De novo DNA methylation Yeast

SOME CHARACTERISTICS OF THE AVHRR MEASUREMENTS FOR SOME GEOGRAPHICAL REGIONS OVER THE WEST OF CHINA

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高原气象 1991年第2期10卷 166-173页

作者： wei li zhong Qiang(Lanzhou Institute of Plateau Atmospheric Physics, The Chinese Academy of Sciences) 中科院兰州高原大气物理所甘肃兰州

In this paper,some characteristics of the AVHRR measurements（spectral reflectances,vegetation index and window brightnesses）are analysed for several representative regions（50×50 km;）with different underlying surf... 详细信息

关键词： AVHRR data Reflectance Vegetation index Brightness temper-ature

Design and Synthesis of a Novel Peptidomimetic Inhibitor of Caspase-3

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Chemical Research in Chinese Universities 2006年第2期22卷 225-228页

作者： ZHANG Jin-liang liU lin-hua GUO Yang-hong YANG Jin-gang li wei zhong Da-fang WANG Ji-dong College of life Science Jilin University Changchun 130021 P. R. China

Caspases, a family of cysteine proteases, comprise of highly homologous enzymes that play an important role in apoptotic cell death. Caspase-3 shows key functions in apoptosis, mediating apoptotic cascade from the intrinsic and extrinsic activation pathways. Therefore, caspase-3 is an attractive target for therapeutic intervention. For instance, inhibitors of caspase-3 have been described as promising cardioprotectants, neuroprotectants and antiarthritic agents. A novel peptidomimetic inhibitor of caspase-3, has been designed, which still has the properties of a reversible inhibitor, while the P1 site at the C-terminal remains, and only L-amino acid has been replaced by D-amino acid. Also presented here is the synthesis of the inhibitor and its inhibitory activity against caspase-3, which was tested by the fluorescent activity assay.

关键词： Caspase-3 Inhibitor Retro-inverso Peptidomimetie Synthesis

Midgut volvulus due to jejunal diverticula:A case report

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World Journal of Gastroenterology 2012年第40期18卷 5826-5829页

作者： Jia-li Hu wei-zhong Chen Department of Gastroenterology Changzheng Hospital Shanghai 200003 China

Jejunal diverticulosis is uncommon and often *** can produce significant complications,and some complications are potentially life threatening and require early surgical treatment,such as obstruction,hemorrhage and *** is no consensus on the management of this *** a few cases of jejunal diverticulosis with midgut volvulus have been *** herein report a case of 57-year-old woman with jejunal diverticulosis causing small bowel volvulus who complained of intermittent upper abdominal pin-prick for 5 years that eventually progressed to a complete *** computed tomography scans revealed a mesenteric vessel "whirlpool" and laparotomy showed midgut volvulus secondary to jejunal *** case highlights jejunal diverticulosis causing small bowel volvulus as an uncommon mechanism of small bowel obstruction,which should be included in the differential diagnosis of small bowel obstruction.

关键词： Jejunal diverticulosis Midgut volvulus In-testinal obstruction Computed tomography Surgery

Optimizing cooling approach of spiral coil for an electromagnetic steel teeming system of ladle in continuous casting production

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Journal of Iron and Steel Research International 2025年第1期32卷 85-94页

作者： Ming He Qing-wei Wang li-jia Zhao Wang-zhong Mu Xing-an liu Qiang Wang College of Horticulture Shenyang Agricultural UniversityShenyang110866LiaoningChina Key Laboratory of Electromagnetic Processing of Materials(Ministry of Education) Northeastern UniversityShenyang110819LiaoningChina Key Laboratory of Protected Horticulture(Ministry of Education) Shenyang Agricultural UniversityShenyang110866LiaoningChina Department of Materials Science and Engineering KTH Royal Institute of TechnologyStockholm10044Sweden

To address the current issues with the conventional slide gate system utilized in the steel teeming process,a unique electromagnetic induction controlled automated steel teeming(EICAST)technology has been *** means of spiral coil in this technology is directly related to its service ***,heat transfer processes of air cooling and spray cooling were compared and ***,the impacts of water temperature,water flow rate and air flow rate were examined in order to maximize the spray cooling *** maintain coil temperature at a low value consistently throughout the entire thermal cycle process of the ladle,a combined cooling mode was finally *** simulation was applied to examine the coil temperature variation with different cooling systems and *** coil operation,spray cooling is said to be more *** controlling the water flow rate and air flow rate,the spray cooling effect is ***,water temperature has little or no impact when using spray *** cooling during the secondary refining process and spray cooling prior to coil operation are combined to further lower coil *** the direction of the spray cooling is from bottom to top,the coil temperature is lowered below 165℃.A practical induction coil cooling plan was provided for the EICAST technology’s production process.

关键词： Electromagnetic induction controlled automated steel teeming technology Spiral coil Spray cooling Heat transfer Continuous casting

NUMERICAL SIMULATION OF HORIZONTAL BUOYANT WALL JET

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Journal of Hydrodynamics 2010年第1期22卷 58-65页

作者： HUAI Wen-xin li Zhi-wei QIAN zhong-dong ZENG Yu-hong HAN Jie PENG Wen-qi State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University Wuhan 430072 China Department of Water Environment China Institute of Water Resources and Hydropower Research Beijing100038 China

This article applies the realizable k - ω model to simulate the buoyant wall jet and gives the results of cling length, centerline trajectory and temperature dilutions at certain sections. The comparison between the numerical results and Sharp＇s experimental data indicates that the model is effective in estimating velocity distribution and temperature dilutions. The velocity profiles at the cental plane and z-plane both show a strong similarity at certain distance from the nozzle, and the distributions of velocity and temperature dilutions also exhibit a similarity along the axial direction at centerline in the near-field. Based on the results, the article gives the corresponding relationships between the distance and the dilutions of velocity and temperature, which is useful in predicting the behavior of the wall buoyant jet.

关键词： buoyancy wall jet cling length velocity profile temperature dilution