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Post-treatment of Ti-MWW zeolite with potassium fluoride for propylene epoxidation

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Frontiers of Chemical Science and engineering 2024年第8期18卷 37-47页

作者： Xintong Li Xianchen Gong Jilong Wang Shengbo Jin Hao Xu Peng Wu State key laboratory of Petroleum molecular&Process engineering Shanghai Key Laboratory of Green Chemistry and Chemical ProcessesSchool of Chemistry and Molecular EngineeringEast China Normal UniversityShanghai 200062China

Epoxidation of propylene to propylene oxide(PO)with hydrogen peroxide(HPPO)is an environmentally friendly and cost-efficient process in which titanosilicates are used as ***-MWW is a potential industrial catalyst for this process,which involves the addition of HPPO to *** silanol groups generated during secondary crystallization unavoidably result in ring-opening of PO and inefficient decomposition of HPPO,which diminish the PO selectivity and the lifespan of *** address this issue,we conducted post-treatment modifications of the structured Bf-Ti-MWW catalyst with potassium fluoride aqueous *** quenching the silanol groups with potassium fluoride and implanting electron-withdrawing fluoride groups into the Ti-MWW framework,both the catalytic activity and HPPO utilization efficiency were ***,the ring opening reaction of PO was *** a continuous fixed-bed liquid-phase propylene epoxidation reaction,the KF-treated structured Ti-MWW catalyst displayed an exceptionally long lifespan of 2700 h,with a PO yield of 590 g·kg^(-1)·h^(-1).

关键词： titanosilicates Ti-MWW propylene epoxidation structured catalyst KF modification

Permeability and selectivity synergistically enhanced nanofluidic membrane for osmotic energy harvesting

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Carbon Energy 2024年第8期6卷 14-24页

作者： Jundong Zhong Tingting Xu Hongyan Qi Weibo Sun Shuang Zhao Zhe Zhao Yirong Sun Youliang Zhu Jianxin Mu Haibo Zhang Xuanbo Zhu Zhenhua Jiang Lei Jiang National and Local Joint engineering laboratory for Synthetic Technology of High‐Performance Polymer Jilin UniversityChangchunJilinChina State key laboratory of Supramolecular Structure and Materials Jilin UniversityChangchunJilinChina key laboratory for molecular enzymology and engineering of Ministry of Education Jilin UniversityChangchunJilinChina CAS key laboratory of Bio‐inspired Materials and Interfacial Science Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijingChina

For the porous‐membrane‐based osmotic energy generator,the potential synergistic enhancement mechanism of various key parameters is still controversial,especially because optimizing the trade‐off between permeability and selectivity is still a ***,to construct a permeability and selectivity synergistically enhanced osmotic energy generator,the twodimensional porous membranes with tunable charge density are prepared by inserting sulfonated polyether sulfone into graphene *** of charge density and pore size on the ion transport are explored,and the ionic behaviors in the channel are calculated by numerical *** mechanism of ion transport in the process is studied in depth,and the fundamental principles of energy conversion are *** results demonstrate that charge density and pore size should be matched to construct the optimal ion *** collaborative enhancement strategy of permeability and selectivity has significantly improved the output power in osmotic energy generation;compared to the pure graphene oxide membrane,the composite membrane presents almost 20 times improvement.

关键词： blue energy generator charge tunable graphene oxide ion transport layered nanocomposites

Micelle-directed self-assembly of single-crystal-like mesoporous stoichiometric oxides for high-performance lithium storage

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National Science Review 2024年第4期11卷 195-205页

作者： Yanhua Wan Changyao Wang Xingmiao Zhang Yang Yin Mengmeng Liu Bing Ma Linlin Duan Yuzhu Ma Wei Zhang Changlin Zheng Dongliang Chao Fei Wang Yongyao Xia Wei Li Department of Chemistry Laboratory of Advanced Materials Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials State Key Laboratory of Molecular Engineering of Polymers College of Chemistry and Materials ScienceFudan University State key laboratory of Surface Physics and Department of Physics Fudan University

Due to their uncontrollable assembly and crystallization process,the synthesis of mesoporous metal oxide single crystals remains a formidable ***,we report the synthesis of single-crystal-like mesoporous Li2TiSiO5by using soft micelles as *** key lies in the atomic-scale self-assembly and step-crystallization processes,which ensure the formation of single-crystal-like mesoporous Li2TiSiO5microparticles via an oriented attachment growth mechanism under the confinement of an in-situ formed carbon *** mesoporous Li2TiSiO5anode achieves a superior rate capability(148 mAh g-1at5.0 A g-1) and outstanding long-term cycling stability(138 mAh g-1after 3000 cycles at 2.0 A g-1) for lithium storage as a result of the ultrafast Li+diffusion caused by penetrating mesochannels and nanosized crystal frameworks（5-10 nm）.In comparison,bulk Li2TiSiO5exhibits poor rate capability and cycle performance due to micron-scale diffusion *** method is very simple and reproducible,heralding a new way of designing and synthesizing mesoporous single crystals with controllable frameworks and chemical functionalities.

关键词： mesoporous materials micelles single-crystal-like Li2TiSiO5 lithium-ion batteries

Polyelectrolyte Complexes and Coacervates Formed by De novo-Designed Peptides and Oligonucleotide

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Chinese Journal of Polymer Science 2024年第9期42卷 1333-1340,I0007页

作者： Tian-Hao Ren De-Hai Liang Beijing National laboratory for molecular Sciences Department of Polymer Science and Engineering and the Key Laboratory of Polymer Chemistry and Physics of the Ministry of EducationCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing100871China

The liquid-liquid phase separation of biopolymers in living cells contains multiple interactions and occurs in a dynamic *** the regulation mechanism is still a *** this work,we designed a series of peptides(XXLY)_(6)SSSGSS and studied their complexation and coacervation behavior with single-stranded ***“X”and“Y”are varied to combine known amounts of charged and non-charged amino acids,together with the introduction of secondary structures and pH *** show that the electrostatic interaction,which is described as charge density,controls both the strength of complexation and the degree of chain relaxation,and thus determines the growth and size of the *** hydrophobic interaction is prominent when the charges are ***,the secondary structures of peptides exhibit profound effect on the morphology of the phases,such as solid phase to liquid phase *** study gains insight into the phase separation under physiological *** is also helpful to create coacervates with desirable structures and functions.

关键词： Polyelectrolyte complex Coacervate Peptides Secondary structure Electrostatic interaction

Interparticle energy transfer between NaNdF_(4) and NaYbF_(4) in self-assembled nanostructures

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Journal of Rare Earths 2024年第6期42卷 1029-1035,I0001页

作者： Xinyu Chen Haoze Yang Yuyang Gu Chenqing Wen Yishuo Sun Jiaming Ke Wei Feng Department of Chemistry and State key laboratory of molecular engineering of Polymers Fudan University Shanghai200433China

Forster resonance energy transfer(FRET)is a widely used spectroscopic *** development of donor-acceptor combinations is essential to advance this *** make the energy transfer efficiency independent of the external environment,we explored the potential of constructing donor—acceptor combinations with lanthanide ion-doped nanoparticles(LNPs),in which the 4f electrons of the lanthanide ions are shielded by the 5s and 6p ***-radiative energy transfer between LNPs was demonstrated in self-assembled nanostructures and core-shell structure of LNPs was used to control the distance between donor and acceptor in self-assembled *** emission intensity ratio of donor and acceptor illustrates that the energy transfer efficiency decreases significantly with increasing distance and the effective energy transfer distance is 8.5 nm,showing the potential of using LNPs as donor-acceptor pairs in the construction of distance-dependent energy transfer system.

关键词： Lanthanide nanoparticles Self-assembly Energy transfer Distance Epitaxialgrowth Rare earths

Self-assembly Induced by Complexation of Diblock Copolyelectrolytes and Oppositely Charged Homopolymers

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Chinese Journal of Polymer Science 2024年第9期42卷 1321-1332,I0006页

作者： Ling Zhao Zhi-Yuan Yin Jia-Di Jiang Er-Qiang Chen Shuang Yang Beijing National laboratory for molecular Sciences Key Laboratory of Polymer Chemistry and Physics of Ministry of EducationCenter for Soft Mater Science and EngineeringCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing100871China Beijing National laboratory for molecular Sciences College of Chemistry and Molecular EngineeringPeking UniversityBeijing100871China

We investigate the solution self-assembly of a mixture of positively charged homopolymers and AB diblock copolymers,in which the A blocks are negatively charged,and the B blocks are *** electrostatic complexation between oppositely charged polymers drives the formation of many ordered *** microstructures and phase diagrams are calculated using self-consistent field theory(SCFT)based on an ion-pair model with an equilibrium constant K to characterize the strength of binding between positively and negatively charged *** effects of the charge ratio,representing the ratio of charges from the homopolymer over all charges from polymers in the system,on the ordered structure are systematically studied,both for hydrophobic and hydrophilic A *** charge ratio plays an important role in determining the phase boundaries in the phase diagram of salt concentration versus polymer *** also provide information about the varying tendency of the domain spacing and core size of the spherical phase when the charge ratio is changed,and the results are in good agreement with *** studies provide a deep understanding of the self-assembled microstructures of oppositely charged diblock copolymer-homopolymer systems.

关键词： Self-assembly Polyelectrolyte complexation Self-consistent field theory Ion-pair

Production of Functional Materials Derived from Regenerated Silk Fibroin by Utilizing 3D Printing and Biomimetic Enzyme-induced Mineralization

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Chinese Journal of Polymer Science 2024年第3期42卷 299-310,I0005页

作者： Ni Chen Fei-Yu Luo Gong-Wen Yang Jin-Rong Yao Xin Chen Zheng-Zhong Shao State key laboratory of molecular engineering of Polymers Laboratory of Advanced Materials and Department of Macromolecular ScienceFudan UniversityShanghai 200433China

Critical-sized bone defects, commonly encountered in clinical orthopedic surgery, present a significant challenge. One of the promising solutions is to prepare synthetic bone substitute materials with precise structural control, mechanical compatibility, and enhanced osteogenic induction performance, nevertheless the successful preparation of such materials remains difficult. In this study, a two-step technique,integrating an extrusion-based printing process with biomimetic mineralization induced by alkaline phosphatase(ALP), was developed. Initially,a pre-cured hydrogel of regenerated silk fibroin(RSF) with a small quantity of hydroxypropyl cellulose(HPC) and ALP was prepared through heating the mixed aqueous solution. This pre-cured hydrogel demonstrated thixotropic property and could be directly extruded into predetermined structures through a 3D-printer. Subsequently, the 3D-printed RSF-based materials with ALP underwent biomimetic in situ mineralization in calcium glycerophosphate(Ca-GP) mineralizing solution, utilizing the polymer chains of RSF as templates and ALP as a trigger for cleaving phosphate bonds of Ca-GP. The resulting 3D-printed RSF-mineral composites including hydrogel and sponge possessed adjustable compression modulus of megapascal grade and variable hydroxyapatite content, which could be controlled by manipulating the duration of the mineralization ***, these 3D-printed RSF-mineral composites demonstrated non-cytotoxicity towards rat bone marrow mesenchymal stem cells. Therefore, they may hold great potential for applications involving the replacement of tissues characterized by osteoinductivity and intricate structures.

关键词： Silk protein Alkaline phosphatase Extrusion-based printing Biomineralization

Effects of serum proteins on corrosion rates and product bioabsorbability of biodegradable metals

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Regenerative Biomaterials 2024年第1期3卷 132-148页

作者： Hongjie Zhang Xin Li Zehua Qu Wanqian Zhang Qunsong Wang Dinglingge Cao Yaoben Wang Xin Wang Yang Wang Lin Yu Jiandong Ding State key laboratory of molecular engineering of Polymers Department of Macromolecular ScienceFudan UniversityShanghai 200438China

Corrodible metals are the newest kind of biodegradable materials and raise a new problem of the corrosion ***,the removal of the precipitated products has been unclear and even largely ignored in ***,we find that albumin,an abundant macromolecule in serum,enhances the solubility of corrosion products of iron in blood mimetic Hank’s solution *** is universal for other main biodegradable metals such as magnesium,zinc and polyester-coated *** also influences corrosion rates in diverse trends in Hank’s solution and normal *** on quantitative study theoretically and experimentally,both the effects on corrosion rates and soluble fractions are interpreted by a unified mechanism,and the key factor leading to different corrosion behaviors in corrosion media is the interference of albumin to the Ca/P passivation layer on the metal *** work has illustrated that the interactions between metals and media macromolecules should be taken into consideration in the design of the next-generation metal-based biodegradable medical devices in the formulism of precision *** improved Hank’s solution in the presence of albumin and with a higher content of initial calcium salt is suggested to access biodegradable metals potentially for cardiovascular medical devices,where the content of calcium salt is calculated after consideration of chelating of calcium ions by albumin,resulting in the physiological concentration of free calcium ions.

关键词： biodegradable metal macromolecule albumin corrosion bioabsorbability iron polylactide magnesium zinc

Mechanisms of inclusion-induced pitting of stainless steels:A review

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Journal of Materials Science & Technology 2024年第1期168卷 143-156页

作者： Yangting Sun Xin Tan Rulei Lan Guoyong Ran Jin Li Yiming Jiang Department of Materials Science State Key Laboratory of Molecular Engineering of PolymersFudan UniversityShanghai 200438China

Pitting is a common type of localized corrosion in passive alloys that can cause rapid failure of material or *** the case of stainless steels,non-metallic inclusions have been identified as the most susceptible sites for pitting,and have therefore garnered significant *** review critically ex-amines the issue of how inclusions induce pitting,with a particular focus on three mechanisms:sponta-neous dissolution of inclusions,active dissolution of Cr-depleted regions,and propagation of microcracks at the inclusion-matrix *** researchers have made significant strides in understanding these mechanisms over the past few decades,many gaps and controversies *** such as the ini-tial driving force of inclusion dissolution and factors affecting Cr-depleted regions require further ***,some old concepts and methods need to be revised to arrive at more credible *** review aims to delve deeply into these important issues and provide inspiration for future research.

关键词： Pitting Inclusion Stainless steel Localized corrosion MnS