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Rare Metals 2024年第2期43卷 533-542页

作者： Wei Li Jia-Jun Li Zhi-Fei Liu hong-yu ma Peng-Fei Fang Rui Xiong Jian-hong Wei Key Laboratory of Artificial Micro-and Nano-Structures of Ministry of Education School of Physics and TechnologyWuhan UniversityWuhan430072China

Constructing a S-scheme heterojunction with tight interface contact and fast charge transfer is beneficial to improving the photocatalytic hydrogen evolution performance.Herein,a unique one-dimensional(1D)/two-dimensional(2D)S-scheme heterojunction containing 1D Sb_(2)S_(3) nanorods and 2D ZnIn_(2)S_(4) with affluent sulfur vacancies(denoted as Sv-ZnIn_(2)S_(4)@Sb_(2)S_(3)) was designed.The introduced sulfur vacancy can promote the effective adsorption of H+for the following interfacial hydrogen-evolution reaction.Furthermore,the larger contact area and stronger electron interaction between Sb_(2)S_(3) and ZnIn_(2)S_(4) effectively inhibits the recombination of photo-generated electron–hole pairs and abridges the migration distance of charges.As a result,the optimal Sv-ZnIn_(2)S_(4)@Sb_(2)S_(3) sample achieves H_(2) evolution activity of 2741.3 mol·h^(−1)·g^(−1),which is 8.6 times that of pristine ZnIn_(2)S_(4) and 3.0 times that of the Sv-ZnIn_(2)S_(4) samples.Based on the experimental result,the photo-reactivity S-scheme mechanism of hydrogen evolution from water splitting with Sv-ZnIn_(2)S_(4)@Sb_(2)S_(3) is proposed.This work provides an effective method for developing S-scheme heterojunction composites of transition metal sulfide with high hydrogen evolution performance.

关键词： ZnIn_(2)S_(4) nanosheets S-scheme heterojunction Sulfur vacancy Charge transfer and separation Photocatalytic H_(2)evolution

Synthetic Features and Mechanism for the Preparation of Vinyl Chloride-co-Butyl Acrylate-co-Vinyl Acetate Terpolymer via Precipitation Polymerization

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Chinese Journal of Polymer Science 2023年第11期41卷 1714-1724,I0006页

作者： Chang-Tong Song Xian-hong Zhang Dong Chen yu-hong ma Wan-Tai Yang State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing 100029China College of material Science and Engineering Beijing University of Chemical TechnologyBeijing 100029China

Without any type of su rfactant or dispersing agent,precipitation polymerization has great superiorities in both polymer synthesis and applications.In the present work,the polymerization of vinyl chloride(VC),n-butyl acrylate(BA),and vinyl acetate(VAc)are conducted in the precipitation polymerization system and series of their random terpolymers poly(vinyl chloride-co-n-butyl acrylate-co-vinyl acetate)(PCBV)are synthesized successfully.The effects of various polymerization conditions,including solvent polarity,temperature,initiator concentration,and monomer feed ratios on the polymerization kinetics,number-average molecular weight(M_(n)),and terpolymer composition are investigated systematically.The solvent and the monomer feed ratio are crucial factors not only for the polymer morphology,but also for the reaction kinetic.In the non-polar solvent such as n-hexane,the PCBV displays particle morphology when the composition of BA ratio lower than 10 wt%.Otherwise,the PCBV forms a uniform polymer phase and precipitates out from the mixture.In the polar solvent,e.g.,dimethyl carbonate(DMC)and ethanol,the PCBV polymer maintains a slurry state either in low or in high monomer feed ratio.Impressively,VC based ternary copolymer that obtained in n-hexane has much lower M_(n)(mass fraction(>40 wt%)compared with emulsion and suspension polymerization.Additionally,the terpolymer can be easily sepa rated by simple centrifugation.

关键词： Precipitation polymerization Copolymerization Vinyl chloride Low molecular weight

Conventional Radical and RAFT Alternating Copolymerizations of Hydroxyalkyl Vinyl Ethers and Dialkyl maleates

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Chinese Journal of Polymer Science 2023年第12期41卷 1856-1867,I0006页

作者： Yan-Xin Zhang Dong Chen Gao-Fei Hu yu-hong ma Wan-Tai Yang Beijing Engineering Research Center of Syntheses and Applications of Waterborne Polymers College of materials Science and Engineering Beijing University of Chemical TechnologyBeijing 100029China Analytical and Testing Center Beijing University of Chemical TechnologyBeijing 100029China

The alternating copolymerization of hydroxyalkyl vinyl ethers and dialkyl maleates is investigated by conventional radical polymerization and reversible addition-fragmentation chain transfer polymerization(RAFT).The influence of comonomer structure,comonomer feeding ratios,and monomer concentrations on the copolymerization and the copolymer structure have been investigated systematically.With 2-hydroxyethyl vinyl ether(HEVE)and dimethyl maleates(DMM)as comonomers,a well-defined alternating copolymer is prepared with M_(n)=3400 and M_(w)/M_(n)=1.93 up to 71.6% monomer.The alternating sequential chain structure of the copolymers has been proved by both NMR and matrixassisted laser desorption/ionization time-of-flight mass spectrometry(maLDI-TOF MS).The experimental reactivity ratios and theoretical calculated highest occupied molecular orbital and the lowest unoccupied molecular orbital of vinyl ethers and alkyl maleates support that these monomer pairs have tendency to form alternating copolymers.With 2-cyanopropan-2-yl N-methyl-N-(pyridin-4-yl)carbamodithioate as the RAFT agent,the molecular weight of HEVE and DMM copolymer increases with the monomer conversion,demonstrating a controlled radical polymerization feature with well-controlled molecular weight and relatively narrower molecular weight distribution.With alternating copolymer of HEVE and DMM as macro-CTA(M_(n)=5200 and M_(w)/M_(n)=1.46),both the chain extension with HEVE and DMM(M_(n)=10400 and M_(w)/M_(n)=1.72)and block copolymerization with vinyl acetate have been successfully achieved(M_(n)=8500 and M_(w)/M_(n)=1.52).

关键词： Radical polymerization Vinyl ethers maleates Alternating copolymer RAFT polymerization

Polypropylene/Silica Nanocomposites in situ Prepared via Sol-Gel Reactions Using Porous Spherical Poly(propylene-g-(styrene-alt-maleic anhydride)) Granules as Reaction Loci

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Chinese Journal of Polymer Science 2015年第12期33卷 1730-1740页

作者： Zhuo Li yu-hong ma 杨万泰 The State Key Laboratory of Chemical Resources Engineering Beijing University of Chemical Technology Key Laboratory of Carbon Fiber and Functional Polymers Ministry of Education Beijing University of Chemical Technology

Using the porous polypropylene （PP） granules consisting of submicroparticles prepared by the reactor granular technology （RGT）, a facile process was developed to synthesize in situ polypropylene/silica nanocomposites where styrene- alt-maleic anhydride copolymers （PSM） were firstly grafted onto both the outer- and the inner-pore surfaces of PP granules via solid-phase grafting polymerization, and then a sol-gel reaction was conducted inside these micro-pores with the carboxyl acid derived from maleic anhydride as catalyst. TEM micrographs demonstrated that the silica nanoparticles obtained by this strategy had a size around 10-20 nm in diameter and uniformly dispersed in the PSM-based nanocomposites. More importantly, the silica nanoparticles could significantly reduce the size of PP spherulites. Consequently, the PP/silica nanocomposites with high transparency and good mechanical performance were achieved.

关键词： Nanocomposites Solid-state polymerization Silica.

Preparation of Ultralow Molecular Weight Poly(vinyl chloride) with Submicrometer Particles via Precipitation Polymerization

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Chinese Journal of Polymer Science 2019年第7期37卷 646-653页

作者： Peng Cui Chang-Tong Song Xian-hong Zhang Dong Chen yu-hong ma Wan-Tai Yang State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing 100029China College of material Science and Engineering Beijing University of Chemical TechnologyBeijing 100029China

Poly(vinyl chloride), with ultralow molecular weight, produced by free radical polymerization either at high temperature or in the presence of chain transfer agents, is widely used as special resins and polymer process additives. This paper reports a new process, called self-stabilized precipitation polymerization, in which the polymerization of vinyl chloride monomer (VCM) is conducted in hydrocarbon diluents without addition of any suspending agent or emulsifier. The merits of this novel strategy include:(1) PVC resins with ultra-low number-average molecular weight (Mn) from 4000 to 15000, which is much lower than Mn of those prepared by conventional suspension and emulsion polymerizations,(2) sub-micrometer PVC particles with near spherical morphology, and (3) the very simple post-polymerization separation process. Under mild stirring, polymerization proceeds stably and smoothly. The influences of main process factors, such as solvents, initiator and monomer concentrations, polymerization time, and temperature on both particle morphology and Mn of the polymer products are investigated systematically. The molar ratio of-CH2-CHCl-/-CH=CH-CH2CHCl, a good indicator of structural defects, is about 1000/0.1 which means the low molecular weights do not result from chain transfer to the monomers. Then the mechanism of this polymerization is proposed. In summary, this novel polymerization technology provides a straightforward method for preparing PVC particulate products with low Mn.

关键词： Precipitation polymerization Vinyl chloride Ultralow molecular weight Pure product

A facile method to prepare polypropylene/poly(butyl acrylate)alloy via water–solid phase suspension grafting polymerization

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Chinese Chemical Letters 2015年第11期26卷 1351-1354页

作者： Zhuo Li Li Wang yu-hong ma Wan-Tai Yang The State Key Laboratory of Chemical Resources Engineering Beijing University of Chemical Technology Key Laboratory of Carbon Fiber and Functional Polymers Ministry of Education Beijing University of Chemical Technology

Polypropylene/poly（butyl acrylate） alloy is produced by water-solid phase suspension grafting polymerization with a submicrometer microdomain where graft polymerization occurs within micropores of polypropylene particles prepared by reactor granule technology （RGT）. The results show that the grafting percentage （GP） of butyl acrylate （BA） increases with the increase of the monomer concentration, which could reach 32.6% while the grafting efficiency （GE） is up to 98%. The addition of the crosslinking agent, triethylene glycol diacrylate （TEGDA）, could improve GP up to 36.3%. Transmission electron microscopic （TEM） micrographs demonstrate that PBA microdomains distributed in PP matrix increase in size less than 500 rim. Moreover, TEM images show that the grafting phase exhibits a singlephase behavior with the addition of TEGDA, which implies that the ratio of graft copolymer increased.

关键词： GraftingRadical polymerizationPorous materialsCrosslinking

Facile Construction of Synergistic β-Glucosidase and Cellulase Sequential Co-immobilization System for Enhanced Biomass Conversion

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Chinese Journal of Polymer Science 2020年第12期38卷 1277-1285页

作者： Guan Wang Kai Zhang Jia-Yi Xin Chang-Wen Zhao yu-hong ma Wan-Tai Yang State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing 100029China Beijing Laboratory of Biomedical materials Beijing University of Chemical TechnologyBeijing 100029China Beijing Advanced Innovation Centre for Soft matter Science and Engineering Beijing University of Chemical TechnologyBeijing 100029China Key Laboratory of Carbon Fiber and Functional Polymers Ministry of EducationBeijing University of Chemical TechnologyBeijing 100029China

Converting renewable cellulose into glucose via cellulase catalysis for further production of biofuel has been recognized as one of the most promising ways for solving energy crisis.However,the hydrolysis performance of immobilized cellulase was not satisfactory for practical application due to the reduced catalytic efficiency and lack of β-glucosidase(BG)component in cellulase.Here,a facile method was developed to sequentially co-immobilize BG and cellulase by polymeric microparticles with hierarchical structure.In this strategy,BG was firstly entrapped into the cross-linked poly(ethylene glycol)(PEG)microparticles via inverse emulsion polymerization initiated by isopropyl thioxanthone(ITX)under the irradiation of visible light,leaving the formed ITX semi-pinacol(ITXSP)dormant groups on surface of BG-loaded microparticles,which could be further activated by visible light irradiation and initiated a graft polymerization to introduce poly(acrylic acid)(PAA)brush on the PEG core.After that,cellulase was covalently bonded on the PAA chains via carbodiimide reaction.The synergic effect of BG and cellulase was verified in the dual enzyme immobilization system,which led to a better stability at a wide range of temperature and pH than free enzymes.The dual enzymes system exhibited excellent reusability,which could retain 75%and 57%of the initial activity after 10 cycles of hydrolysis of carboxyl methyl cellulose and 5 cycles of hydrolysis of filter paper,respectively,indicative of the potential in biofuel areas in a cost-effective manner.

关键词： Visible light Grafting polymerization Enzyme immobilization Cellulase

Pancreatic cancer secondary to intraductal papillary mucinous neoplasm with collision between gastric cancer and B-cell lymphoma: A case report

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World Journal of Clinical Cases 2021年第10期9卷 2400-2408页

作者： yu-hong ma Tatsuya Yamaguchi Tomoki Yasumura Toru Kuno Shoji Kobayashi Takashi Yoshida Takeshi Ishida Yasuaki Ishida Shinya Takaoka Jiang-Lin Fan Nobuyuki Enomoto Department of Gastroenterology Ningxia Hui Autonomous Region People’s HospitalYinchuan 750021Ningxia Hui Autonomous RegionChina Department of the First Internal Medicine Faculty of MedicineUniversity of YamanashiChuo 409-3898YamanashiJapan Department of Molecular Pathology Interdisciplinary Graduate School of Medicine and EngineeringUniversity of YamanashiChuo 409-3898YamanashiJapan

BACKGROUND Patients with intraductal papillary mucinous neoplasm(IPMN)have an increased risk of pancreatic and extrapancreatic malignancies.Lymphomas are rare extrapancreatic malignancies,and in situ collisions of early gastric cancer and diffuse large B-cell lymphoma(DLBCL)are even rarer.Here,we report the first case of pancreatic cancer comorbid with in situ collision of extrapancreatic malignancies(early gastric cancer and DLBCL)in a follow-up IPMN patient.Furthermore,we have made innovations in the treatment of such cases.CASE SUMmaRY An 81-year-old Japanese female diagnosed with IPMN developed elevated carbohydrate antigen(CA)19-9 levels during follow-up.Because her CA19-9 levels continued to rise,endoscopic ultrasound(EUS)was performed and revealed a suspicious lesion at the pancreatic tail.However,lesions in the pancreas were not found by computed tomography,magnetic resonance imaging,or endoscopic retrograde cholangiopancreatography.To make an exact pathological diagnosis,EUS-guided fine needle aspiration was performed.To our supprise,early gastric cancer was found in preoperative gastroscopy.The gastric cancer was completely resected through endoscopic submucosal dissection before postoperative pathology identified early adenocarcinoma collided with DLBCL.Subsequent EUS-guided fine needle aspiration provided pathological support forthe pancreatic cancer diagnosis, and then laparoscopic distal pancreatectomy andsplenectomy were performed. CA19-9 levels returned to normal postoperatively.CONCLUSION Endoscopic submucosal dissection is appropriate for submucosal lymphomas inpatients intoleratant of chemotherapy. EUS can detect small IPMN-relatedpancreatic tumors.

关键词： Stomach neoplasms Pancreatic intraductal neoplasms Pancreatic neoplasms B-cell lymphoma Treatment Case report

A framework from point clouds to workpieces

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Visual Computing for Industry,Biomedicine,and Art 2022年第1期5卷 250-267页

作者： Li‑Yong Shen Meng‑Xing Wang hong‑yu ma Yi‑Fei Feng Chun‑Ming yuan School of mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China KLMM Academy of Mathematics and Systems SciencesUniversity of Chinese Academy of SciencesBeijing 100049China

Combining computer-aided design and computer numerical control(CNC)with global technical connections have become interesting topics in the manufacturing industry.A framework was implemented that includes point clouds to workpieces and consists of a mesh generation from geometric data,optimal surface segmentation for CNC,and tool path planning with a certified scallop height.The latest methods were introduced into the mesh generation with implicit geometric regularization and total generalized variation.Once the mesh model was obtained,a fast and robust optimal surface segmentation method is provided by establishing a weighted graph and searching for the minimum spanning tree of the graph for extraordinary points.This method is easy to implement,and the number of segmented patches can be controlled while preserving the sharp features of the workpiece.Finally,a contour parallel tool-path with a confined scallop height is generated on each patch based on B-spline fitting.Experimental results show that the proposed framework is effective and robust.

关键词： Computer numerical control Mesh reconstruction Mesh segmentation Path planning Scallop height

Nuclear phylogenomics of angiosperms and insights into their relationships and evolution

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Journal of Integrative Plant Biology 2024年第3期66卷 546-578页

作者： Guojin Zhang hong ma College of Life Sciences Hunan Normal UniversityChangsha 410081China Department of Biology 510 Mueller LaboratoryHuck Institutes of the Life SciencesThe Pennsylvania State UniversityUniversity ParkPA 16802USA

Angiosperms(flowering plants) are by far the most diverse land plant group with over 300,000 species. The sudden appearance of diverse angiosperms in the fossil record was referred to by Darwin as the “abominable mystery,”hence contributing to the heightened interest in angiosperm evolution. Angiosperms display wide ranges of morphological, physiological,and ecological characters, some of which have probably influenced their species richness. The evolutionary analyses of these characteristics help to address questions of angiosperm diversification and require well resolved phylogeny. Following the great successes of phylogenetic analyses using plastid sequences,dozens to thousands of nuclear genes from next-generation sequencing have been used in angiosperm phylogenomic analyses, providing well resolved phylogenies and new insights into the evolution of angiosperms. In this review we focus on recent nuclear phylogenomic analyses of large angiosperm clades, orders, families,and subdivisions of some families and provide a summarized Nuclear Phylogenetic Tree of Angiosperm Families. The newly established nuclear phylogenetic relationships are highlighted and compared with previous phylogenetic results. The sequenced genomes of Amborella,Nymphaea, Chloranthus, Ceratophyllum, and species of monocots, magnoliids, and basal eudicots, have facilitated the phylogenomics of relationships among five major angiosperms clades. All but one of the 64 angiosperm orders were included in nuclear phylogenomics with well resolved relationships except the placements of several orders. Most families have been included with robust and highly supported placements, especially for relationships within several large and important orders and families.Additionally, we examine the divergence time estimation and biogeographic analyses of angiosperm on the basis of the nuclear phylogenomic frameworks and discuss the differences compared with previous analyses. Furthermore,we discuss the implications of nuclear phylogenomic analyses on ancestral

关键词： angiosperms evolution flowering plants nuclear gene phylogenomics phylogeny