检索结果-南通市图书馆

Counterion-Mediated Hydrogen Bonding Making Strong Polyelectrolytes pH-Responsive:Current Understanding and Perspectives

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2024年第9期42卷 1270-1277,I0005页

作者： Yue Huang guang-Tao Mei Zan Hua guang-ming liu Hefei National Research Center for Physical Sciences at the Microscale Department of Chemical PhysicsKey Laboratory of Surface and Interface Chemistry and Energy Catalysis of Anhui Higher Education InstitutesUniversity of Science and Technology of ChinaHefei230026China The Key Laboratory of Functional Molecular Solids Ministry of Educationand Department of Materials ChemistrySchool of Chemistry and Materials ScienceAnhui Normal UniversityWuhu214002China

The counterion-mediated hydrogen bonding(CMHB)is related to the hydrogen bonding between bound counterions and polyelectrolyte chains in polyelectrolyte systems,where the counterions can both electrostatically bind to the charged groups of polyelectrolyte chains and act as hydrogen bond donors or acceptors to form hydrogen bonds with the hydrogen bond sites associated with polyelectrolyte chains simultaneously.A large number of literatures illustrate that strong polyelectrolytes(SPs)are insensitive to pH,which severely limmits the applications of SPs as smart ***,our studies have demonstrated that the CMHB makes SPs *** perspective discusses the mechanism of pH responsiveness of SPs and the pH-tunable properties of SPs,based on the pH-controlled CMHB *** future research directions on the pH responsiveness of SPs are also discussed *** is anticipated that the study of the pH responsiveness of SPs not only will provide a new understanding of the fundamental properties of SPs,but also will greatly expand the applications of SPs in the field of smart materials.

关键词： Counterion binding Hydrogen bond Polyelectrolyte brush Polyelectrolyte complexation

In situ Investigation on Layer-by-Layer Deposition of Polyelectrolytes by Quartz Crystal Microbalance

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Physics 2008年第3期21卷 291-294页

作者： Yun-fengYan guang-ming liu Ye-cang Tang guang-zhao Zhang Department of Chemical Physics University of Science and Technology of China Hefei 230025 China

The effect of salt concentration on layer-by-layer deposition of poly（sodium 4-styrene sulfonate）（PSSS）/poly（vinylbenzyl trimethylammonium chloride）（PVTC） was investigated by use of quartz crystal microbalance with dissipation （QCM-D）. The changes in frequency and dissipation demonstrate that the addition of NaC1 leads the thickness of PSSS/PVTC multilayer to increase. The deposition of PSSS/PVTC is dominated by surface charge overcompensation level at lower salt concentrations. However, it is mainly determined by the interpenetration of polyelectrolytes at a higher salt concentration, as reflected in the oscillation of dissipation change.

关键词： Polyelectrolyte Layer-by-layer deposition Quartz crystal microbalance

Revisiting the Thermosensitivity of Poly(acrylamide-co-diacetone acrylamide)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2014年第5期32卷 531-539页

作者： Xin-ming Xing guang-ming liu Yan-wei Ding 张广照 Hefei National Laboratory for Physical Sciences at the Microscale Department of Chemical Physics University of Science and Technology of China Faculty of Materials Science and Engineering South China University of Technology

The lower critical solution temperature （LCST） behavior of poly（acrylamide-co-diacetone acrylamide）（poly（AM-co-DAM）） copolymer in aqueous solutions was studied. The results demonstrate the LCST linearly decreases as the molar fraction of DAM （fDAM） increases. In the range of fDAM 〈 0.36, the transmittance increases as fDAM decreases because the more hydrophilic copolymer chains can form looser aggregates with a lower refractive index. The transmittance exhibits a minimum when fDAM is less than 0.28 as the chains form micelle-like structure with a size smaller than the wavelength. The LCST decreases with the initial polymer concentration, but it levels off when the polymer concentration is high enough. Moreover, no hysteresis can be observed in the change of transmittance during the heating-cooling process because no additional hydrogen bonds are formed in the collapsed state due to the steric hindrance of the large side groups in DAM units.

关键词： Thermosensitive Aggregation Hydrogen bonds Steric hindrance Hysteresis.

Specific Ion Effects on the Enzymatic Degradation of Polyester Films

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2023年第4期41卷 476-482,I0005页

作者： Jian Zhang Jie Zhu Zan Hua guang-ming liu Department of Chemical Physics Key Laboratory of Surface and Interface Chemistry and Energy Catalysis of Anhui Higher Education InstitutesUniversity of Science and Technology of ChinaHefei230026China Key Laboratory of Yarn Materials Forming and Composite Processing Technology of Zhejiang Province College of Material and Textile EngineeringJiaxing UniversityJiaxing314001China Biomass Molecular Engineering Center and Department of Materials Science and Engineering School of Forestry and Landscape ArchitectureAnhui Agricultural UniversityHefei230036China

Soil environment on earth contains a variety of ions,which are expected to play a vital role in the biodegradation of plastics discarded in the *** this work,poly(butyleneadipate-co-terephthalate)(PBAT)is employed as a model biodegradable plastic to study the specific ion effects on the enzymatic degradation of polyester *** results show that the specific ion effects on the enzymatic degradation rate of the PBAT films and on the catalytic rate constant for the enzymatic hydrolysis of the ester bonds are strongly dependent on temperature and ionic *** the enzymatic degradation rate and catalytic rate constant decrease following the trends Na^(+)>K^(+)>Ca^(2+)and Cl^(-)>SO_(4)^(2-)>NO_(3)^(-)for cations and anions,respectively,indicating that the ion-specific enzymatic degradation of the PBAT films is closely correlated with the specific ion effects on enzymatic hydrolysis of the ester *** study shows that the specific ion effects on the enzyme activity can be understood by taking into account the ion-specific cation-anion interaction,ionic dispersion force,salting-out effect and salting-in *** study of specific ion effects on the enzymatic hydrolysis of the ester bonds and the resultant enzymatic degradation of the PBAT films would offer us a new clue to develop new biodegradable,environmentally friendly synthetic plastics.

关键词： Specific ion effects Biodegradable films Ion-enzyme interactions Enzyme activity

Influence of hot rolling on microstructure and mechanical characteristics of explosive-welded FSS/CS laminate

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2018年第5期25卷 572-579页

作者： Xiao-rong Yang Li-feng Ma guang-ming liu guang-hui Zhao Zheng-yi Jiang Shanxi Provincial Key Laboratory of Metallurgical DeviceDesign Theory and Technology Taiyuan University ofScience and Technology Taiyuan 030024 Shanxi China School of Mechanical Materials and Mechatronic Engineering University of Wollongong Wollongong 2522Australia

The influence of hot rolling on the microstructure and subsequent mechanical characteristics of explosive-welded ferritic stainless steel （FSS）/carbon steel （CS） laminate was investigated. The results indicate that by hot rolling, decarburization layer disappears and a uniform structure is gained in CS side, but ferrite grains and carbides in constituent FSS form an uneven band microstructure which is denser at superficial zone than near the interface. The transmission electron microscopy results indicate that the layers adhering to the interface show typical deformed microstructure features, i.e., stream-like strips and elongated grains in FSS plates, carbide precipitates and bended cementite fragments in CS plates; and high-density dislocations in both plates, With hot rolling, various mechanical strengths and hardness are increased, while the elongation percentage is diminished. Examination of fractographs from tensile tests reveals predominately small dimples for explosive-welded specimens, whereas both big dimples and cleavage fracture for rolled specimens. Stereomicroscopic fractographs taken on shear samples indicate that the surfaces of explosive-welded specimens exhibit uniform deformation, but uneven deformation is displayed for that of rolled specimens. These results indicate that hot rolling is beneficial to improve the strength of explosive-welded FSS/CS laminate but not good for enhancing its plasticity.

关键词： Hot rolling · Composite steel plate · Interface ·Ferritic stainless steel ·Carbon steel

The Anion Binding Affinity Determines the Strength of Anion Specificities of Thermosensitive Polymers

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2021年第11期39卷 1351-1356页

作者： Lei-Lei Lian Si-Yuan Xu Hai-Yang Yuan guang-ming liu Hefei National Laboratory for Physical Sciences at the Microscale Key Laboratory of Surface and Interface Chemistry and Energy Catalysis of Anhui Higher Education InstitutesDepartment of Chemical PhysicsUniversity of Science and Technology of ChinaHefei 230026China

In this work,we demonstrate that the strength of anion specificities of thermosensitive polymers is determined by the affinity of direct anion binding to the *** have prepared a series of thermosensitive statistical copolymers with distinct thermoresponsive *** anions can specifically interact with the different types of thermosensitive polymers in very different strengths.A similar strength of specific anion effects on thermoresponsive behaviors can be observed at very different salt concentrations for the different types of thermosensitive polymers.A stronger anion binding to the thermosensitive polymers gives rise to a more obvious anion specificity and vice *** work presented here opens up opportunities for the application of ion binding affinity to modulate the strength of ion specificities of thermosensitive polymers.

关键词： Specific ion effect Polyzwitterion Ion-polymer interaction Thermosensitivity Ion-pairing

Experimental study on Ti+Nb bearing ultra-low carbon bake hardening sheet steel hot-rolled in the ferrite region

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2009年第5期16卷 540-548页

作者： Ji-ping Chen Yong-lin Kang Ying-min Hao guang-ming liu Ai-ming Xiong School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China The State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 China Steel Research Institute of Shougang Beijing 100041 China

A Ti＋Nb bearing ultra-low carbon bake hardening sheet steel hot-rolled in the conventional austenite region and in the ferrite region with lubrication was experimentally studied. Subsequent cold rolling and continuous annealing processes were also conducted. The results show that microstructures of ultra-low carbon bake hardening hot strips at room temperature are basically irregular polygonal ferrites. The yield strength, ultimate tensile strength, n value, and r value of the No.2 specimen hot-rolled in the ferrite region with lubrication are 243 MPa, 364 MPa, 0.29, and 1.74, respectively, which are similar to those of the No.1 specimen hot-roiled in the conventional austenite region. The elongation rate and bake hardening value of No.2 specimen are 51% and 49.4 MPa, respectively, which are greater than those of No. 1 specimen. The No.2 specimen hot-rolled in the ferrite region with lubrication exhibits good mechanical properties and relatively excellent baking hardening performance. Therefore, the hot rolling experiment of Ti＋Nb bearing ultra-low carbon bake hardening steel in the ferrite region with lubrication is feasible and can be considered in the future industrial trial production.

关键词： ultra low carbon steel bake hardening texture microstructure mechanical properties

Storage wall for exascale supercomputing

在线全文

学校读者我要写书评

暂无评论

Frontiers of Information Technology & Electronic Engineering 2016年第11期17卷 1154-1175页

作者： Wei HU guang-ming liu Qiong LI Yan-huang JIANG Gui-lin CAI College of Computer National University of Defense TechnologyChangsha 410073China National Supercomputer Center in Tianjin Tianjin 300457China

The mismatch between compute performance and I/O performance has long been a stumbling block as supercomputers evolve from petaflops to exaflops. Currently, many parallel applications are I/O intensive,and their overall running times are typically limited by I/O performance. To quantify the I/O performance bottleneck and highlight the significance of achieving scalable performance in peta/exascale supercomputing, in this paper, we introduce for the first time a formal definition of the ‘storage wall' from the perspective of parallel application scalability. We quantify the effects of the storage bottleneck by providing a storage-bounded speedup,defining the storage wall quantitatively, presenting existence theorems for the storage wall, and classifying the system architectures depending on I/O performance variation. We analyze and extrapolate the existence of the storage wall by experiments on Tianhe-1A and case studies on Jaguar. These results provide insights on how to alleviate the storage wall bottleneck in system design and achieve hardware/software optimizations in peta/exascale supercomputing.

关键词： Storage-bounded speedup Storage wall High performance computing Exascale computing

Numerical simulation of flow characteristics of side-bottom combined blowing in iron bath reactor

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2023年第2期30卷 236-248页

作者： Yi-bo He Wen-ke Guo Yi-hong Li guang-ming liu Xin Cui School of Materials Science and Engineering Taiyuan University of Science and TechnologyTaiyuan030024ShanxiChina

A numerical model of an iron bath smelting reduction furnace with side-bottom combined blowing was established to study the influence of blowing arrangements on the stirring effect of the molten pool,and the accuracy of numerical simulation was verified by water model *** comparing the flow field of molten pool with single nozzle,double nozzles(symmetrical and asymmetrical),and four nozzles(symmetrical and asymmetrical),the proportion of dead zone,average turbulent kinetic energy,and mixing time,the results show that asymmetrical bottom blowing is better than symmetrical bottom blowing,and the effect of double nozzles bottom blowing was better than that of four nozzles bottom *** mixing effect is the worst under the condition of single *** the bottom blowing is asymmetrical with double nozzles,the mixing time is the *** the condition of double nozzles asymmetrical bottom blowing,when the insertion angle and depth of side lance are larger and deeper,the velocity streamline of molten slag layer is denser and the value is larger;meanwhile,the reflux of molten iron layer is larger,the proportion of dead zone is smaller,and the whole molten pool is fully *** the insertion depth of the side lance is deeper,the gas holdup in the molten pool is greater and the stirring of the molten pool is more intense,while the insertion angle has little effect on the gas *** comparing the influence of different side blowing conditions on the slag layer,it is found that the slag layer is divided into two layers by double-layer side lance,with the critical surface of the slag layer at about 200-260 mm from the bottom,and the insertion depth of the lower side lance has a greater influence on the layering of the slag.

关键词： Iron bath smelting reduction Side-bottom combined blowing Numerical simulation Mixing time Slag layering