Reconfigurable parallel mechanisms were first discovered in response to the growing demand for flexible and adaptive systems in various fields.Unlike traditional mechanisms,which are designed for specific tasks and ha...Reconfigurable parallel mechanisms were first discovered in response to the growing demand for flexible and adaptive systems in various fields.Unlike traditional mechanisms,which are designed for specific tasks and have fixed topology and mobility characteristics,a reconfigurable parallel mechanism can be adapted to different situations by changing its structure,motion,and function.This adaptability enables a single mechanism to perform a wide range of tasks,reducing the need for multiple dedicated systems.This paper presents a comprehensive review of reconfigurable parallel mechanisms.The characteristics of their designs,analyses of their properties,and challenges they face are reported.The beginning of this paper features an introduction of reconfigurable parallel mechanisms and their classification into different types.Methods for synthesizing reconfigurable parallel mechanisms are discussed.A performance evaluation index related to reconfigurability,workspace,singularity,stiffness,and dynamics,among other indices,is presented.This review covers the challenges faced in the creation of systematic design theories,unified performance analyses,evaluation index systems,and in the implementation of reconfigurable parallel mechanisms,such as the development of efficient control strategies and integration with other technologies.The paper concludes with a discussion of future research directions for reconfigurable parallel mechanisms.展开更多
The presence of hydroxyl groups at the C4 and C7 positions in coumarin backbone has been proposed as a potential modification site for providing excellent bioactivity according to previous studies. A series of novel c...The presence of hydroxyl groups at the C4 and C7 positions in coumarin backbone has been proposed as a potential modification site for providing excellent bioactivity according to previous studies. A series of novel coumarin derivatives were rationally designed and synthesized by use of a complex catalytic system for a targeted modification at the above sites. These derivatives were assayed for nematicidal activity. As predicted, the derivatization enhanced the activity of the coumarins against five nematodes.Compounds 7b, 9a, 10 c and 11 c showed significant strong nematicidal broad spectrum activity against all tested nematodes. Compound 10 c was the most effective with the lowest LC50 values against Meloidogyne incognita（5.1 mmol/L）, Ditylenchus destructor（3.7 mmol/L）, Bursaphelenchus mucronatus（6.4 mmol/L）, Bursaphelenchus B. xylophilus（2.5 mmol/L） and Aphelenchoides besseyi（3.1 mmol/L）,respectively. A brief investigation on the structure–activity relationships（SAR） revealed that the targeted modification by a C7 hydroxyl was optimum compared with that of a C4 hydroxyl and that the coupling chain length was crucial for the nematicidal activity.展开更多
A series of transparent ABS（T-ABS） resins were prepared by emulsion in situ suspension polymerization. The influences of the particle size and the content of rubber particles on the transparency of T-ABS resins were...A series of transparent ABS（T-ABS） resins were prepared by emulsion in situ suspension polymerization. The influences of the particle size and the content of rubber particles on the transparency of T-ABS resins were studied by varying the size and content of rubber particles in a single model system（rubber particles with a uniform size）. The optical properties of T-ABS resins were investigated in a mixed system of SBR/PB particles and a hi-modal particle system（rubber particles with two different sizes, 70 and 400 nm in diameter） of SBR particles. It was found that when the size of the smaller particles （ 70 nm） in the mixed system of SBR/PB particles was in the range of 50-100 nm in diameter, the T-ABS resins showed a better transparency. These results provide a flexible and practical process for the preparation of T-ABS resins with good optical and mechanical properties.展开更多
High voltage is necessary for high energy lithium-ion batteries but difficult to achieve because of the highly deteriorated cyclability of the batteries.A novel strategy is developed to extend cyclability of a high vo...High voltage is necessary for high energy lithium-ion batteries but difficult to achieve because of the highly deteriorated cyclability of the batteries.A novel strategy is developed to extend cyclability of a high voltage lithium-ion battery,LiNi_(0.5)Mn_(1.5)O_(4)/Graphite(LNMO/Graphite)cell,which emphasizes a rational design of an electrolyte additive that can effectively construct protective interphases on anode and cathode and highly eliminate the effect of hydrogen fluoride(HF).5-Trifluoromethylpyridine-trime thyl lithium borate(LTFMP-TMB),is synthesized,featuring with multi-functionalities.Its anion TFMPTMB-tends to be enriched on cathode and can be preferentially oxidized yielding TMB and radical TFMP-.Both TMB and radical TFMP can combine HF and thus eliminate the detrimental effect of HF on cathode,while the TMB dragged on cathode thus takes a preferential oxidation and constructs a protective cathode interphase.On the other hand,LTFMP-TMB is preferentially reduced on anode and constructs a protective anode interphase.Consequently,a small amount of LTFMP-TMB(0.2%)in 1.0 M LiPF6in EC/DEC/EMC(3/2/5,wt%)results in a highly improved cyclability of LNMO/Graphite cell,with the capacity retention enhanced from 52%to 80%after 150 cycles at 0.5 C between 3.5 and 4.8 V.The as-developed strategy provides a model of designing electrolyte additives for improving cyclability of high voltage batteries.展开更多
MXene has been the limelight for studies on electrode active materials,aiming at developing supercapacitors with boosted energy density to meet the emerging influx of wearable and portable electronic devices.Despite i...MXene has been the limelight for studies on electrode active materials,aiming at developing supercapacitors with boosted energy density to meet the emerging influx of wearable and portable electronic devices.Despite its various desirable properties including intrinsic flexibility,high specific surface area,excellent metallic conductivity and unique abundance of surface functionalities,its full potential for electrochemical performance is hindered by the notorious restacking phenomenon of MXene nanosheets.Ascribed to its two-dimensional(2D)nature and surface functional groups,inevitable Van der Waals interactions drive the agglomeration of nanosheets,ultimately reducing the exposure of electrochemically active sites to the electrolyte,as well as severely lengthening electrolyte ion transport pathways.As a result,energy and power density deteriorate,limiting the application versatility of MXene-based supercapacitors.Constructing 3D architectures using 2D nanosheets presents as a straightforward yet ingenious approach to mitigate the fatal flaws of MXene.However,the sheer number of distinct methodologies reported,thus far,calls for a systematic review that unravels the rationale behind such 3D MXene structural designs.Herein,this review aims to serve this purpose while also scrutinizing the structure–property relationship to correlate such structural modifications to their ensuing electrochemical performance enhancements.Besides,the physicochemical properties of MXene play fundamental roles in determining the effective charge storage capabilities of 3D MXene-based electrodes.This largely depends on different MXene synthesis techniques and synthesis condition variations,hence,elucidated in this review as well.Lastly,the challenges and perspectives for achieving viable commercialization of MXene-based supercapacitor electrodes are highlighted.展开更多
The vapor recompression heat pump(VRHP) distillation technology offers significant improvements in energy efficiency for distillation systems with small temperature differences between the top and bottom of the column...The vapor recompression heat pump(VRHP) distillation technology offers significant improvements in energy efficiency for distillation systems with small temperature differences between the top and bottom of the column. However, the separation of wide-boiling binary mixtures leads to substantial temperature differences between the top and bottom of the column. This limits the applicability of conventional VRHP due to high capital costs and strict performance requirements of the compressor. To overcome these challenges and to accommodate compressor operating conditions, a novel synthesis and design method is introduced to integrate VRHPs with wide-boiling binary mixture distillation columns(WBMDCs). This method enables quick determination of an initial configuration for the integrated WBMDC-VRHP system and helps identify the optimum configuration with the minimum total annual cost. Two examples, namely the separation of benzene/toluene and isopropanol/chlorobenzene, are employed to derive optimum configurations of the WBMDC-VRHP and compare them with the WBMDC. A systematic comparison between the WBMDC-VRHP and WBMDC demonstrates the superior steady-state performance and economic efficiency of the WBMDC-VRHP.展开更多
Curcumin (curcumin 1, 7-double (4-hydroxy-3-methoxyphenyl) -1, 6-hepadiene-3, 5-diketone) is a natural compound containing dione structure (C21H20O6), with anti-cancer, anti-inflammatory, antibacterial, anti-virus, an...Curcumin (curcumin 1, 7-double (4-hydroxy-3-methoxyphenyl) -1, 6-hepadiene-3, 5-diketone) is a natural compound containing dione structure (C21H20O6), with anti-cancer, anti-inflammatory, antibacterial, anti-virus, anti-infection and other pharmacological activities. In recent years, the domestic and foreign scientists to its structure of the modified compound research results emerge one after another. In this paper, the design and synthesis of curcumin analogues and their antibacterial activities were reviewed, which provided a reference for the study of new curcumin analogues and their antibacterial activities.展开更多
Polymeric nitrogen is a potential high-energy-density material with the advantages of high energy density, easy availability of raw materials, and non-pollution. The design and synthesis of polymeric nitrogen are impo...Polymeric nitrogen is a potential high-energy-density material with the advantages of high energy density, easy availability of raw materials, and non-pollution. The design and synthesis of polymeric nitrogen are important in the research field of energetic materials. The cubic gauche nitrogen was successfully synthesized at high pressure in the diamond anvil cell, which stimulated the theoretical and experimental investigations. To date, several hundred kinds of polymeric nitrogen have been reported. This review introduces the progressive development of polymeric nitrogen with high energy density, the challenges faced by the synthesized polymeric nitrogen under high-pressure,and the importance to improve the stability of polymeric nitrogen at ambient pressure. Furthermore, alternative methods for synthesizing polymeric nitrogen under moderate conditions are also presented. In this field, more efforts are needed to develop strategies for stabilizing more polymeric nitrogen to ambient conditions, especially the stability of free surfaces.展开更多
Two new metal-organic frameworks（MOFs）,[Cu2（H_2O）_2（BCPIA）]（BUT-20）and（Me_2NH_2）[In（BCPIA）]（BUT-21）were designed and synthesized through the solvothermal reaction between a newly created desymmetric 4-co...Two new metal-organic frameworks（MOFs）,[Cu2（H_2O）_2（BCPIA）]（BUT-20）and（Me_2NH_2）[In（BCPIA）]（BUT-21）were designed and synthesized through the solvothermal reaction between a newly created desymmetric 4-connected ligand,5-（2,6-bis（4-carboxyphenyl）pyridin-4-yl）isophthalic acid（H_4BCPIA）and Cu（NO_3）2 2.5H_2O or In（NO_3）_3·5H_2O,respectively,and characterized by single-crystal and powder Xray diffraction,thermogravimetric analysis,infrared spectroscopy,and elemental analysis.The two MOFs have three-dimensional structures,in which both the BCPIA 4 ligand and metal-containing entities,Cu_2（COO）_4（H_2O）_2 and In（COO）_4 act as 4-connected nodes.However,different linkage configurations of the two metal-containing nodes,quadrilateral Cu_2_TD_2（COO）_4（H_2O）_2and tetrahedral In（COO）_4,lead to distinct structural networks of BUT-20 and 21,with Nbo and Unc topologies,respectively.展开更多
Two cyanide bridged trinuclear compounds [Fe（bpy）2（CN）2]·[Cu（Cyclam）]2（ClO4）4·DMF 1 and [Fe（Phen）2（CN）2]·[Cu（Cyclam）]2（ClO4）4·2CH3CN·4H2O 2 （Bpy = 2,2＇- bipyridine, Phen = 1,...Two cyanide bridged trinuclear compounds [Fe（bpy）2（CN）2]·[Cu（Cyclam）]2（ClO4）4·DMF 1 and [Fe（Phen）2（CN）2]·[Cu（Cyclam）]2（ClO4）4·2CH3CN·4H2O 2 （Bpy = 2,2＇- bipyridine, Phen = 1,10-phenanthroline, Cyclam = 1,4,8,11-tetraaza-cyclotetradecane, and DMF = N,N-dimethylformamide） have been synthesized by using mononuclear [Fe（Phen）2（CN）2]·2H2O and [Fe（bpy）2（CN）2]·3H2O as precursors. These two complexes crystallize in monoclinic space groups P21/c and C2/c, respectively. For 1, a = 25.164（2）, b = 12.0405（11）, c = 20.4433（15） A, β = 91.948（3）°, V = 6190.5（9） A^3, Z = 4, Mr = 1418.90, Dc = 1.522 g/cm^3, F（000） = 2936, μ = 1.161 mm^-1, the final R = 0.0722 and wR = 0.2011 for 10779 observed reflections （I 〉 2σ（I））. For 2, a = 43.5945（0）, b = 11.8447（0）, c = 29.5637（2）A, β = 120.430（11）o, V = 13162.76（9） A^3, Z = 8, Mr = 1518.48, Dc = 1.533 g/cm^3, F（000） = 6288, μ = 1.101 mm^-1, the final R = 0.0711 and wR = 0.1783 for 11262 observed reflections （I 〉 2σ（I））.展开更多
Today＇s manufacturing cnvironmem forces manufacturing companies to make as many product variations as possible at affordable costs within a short time. Mass customisation is one of most important technologies for com...Today＇s manufacturing cnvironmem forces manufacturing companies to make as many product variations as possible at affordable costs within a short time. Mass customisation is one of most important technologies for companies to achieve their objectives. Efforts to mass customisation should be made on two aspects： （1） To modularize products and make them as less differences as possible; （2） To design manufacturing resources and make them provide as many processes variations as possible. This paper reports our recent work on aspect （2）, i.e. how to design a reconfignrable manufacturing system （RMS） so that it can be competent to accomplish various processes optimally; Reconfignrable robot system （RRS） is taken as an example. RMS design involves architecture design and configuration design, and configuration design is further divided in design analysis and design synthesis. Axiomatic design theory （ADT） is applied to architecture design, the features and issues of RRS configuration design are discussed, automatic modelling method is developed for design analysis, and concurrent design methodology is presented for design synthesis.展开更多
In this article,studies on the multimode excitation problem of waveguides and antennas,the balance/unbalance mech-anism and the balanced feeding techniques in dipole antenna systems are first briefly historically revi...In this article,studies on the multimode excitation problem of waveguides and antennas,the balance/unbalance mech-anism and the balanced feeding techniques in dipole antenna systems are first briefly historically reviewed.In this context,general-ized odd-even mode theory is advanced to quantitatively and approximately describe the mutual coupling effect between a feed line and an antenna.As is mathematically deduced and demonstrated,the modal parity mismatch between the feed line and the antenna should ultimately dominate the unbalance phenomenon in antenna systems.Thus,an elegant,closed-form formula is derived to ap-proximately calculate the“unbalance degree”of a straight dipole off-center fed by a symmetric twin-wire line.Design approaches for the simplest,linear,1-D multimode resonant antennas are introduced.Moreover,the“falling tone excitation”law gauged based on prototype dipoles is revealed and used to develop a mode synthesis design approach for microstrip patch antennas(MPAs)and 2-D sectorial electric dipole antennas.Design examples with distinctive radiation performance are presented and discussed.Finally,possible development trends of multimode resonant antennas are prospected.展开更多
Acinetobacter baumannii infections pose a great threat to public health owing to upsurging antibiotic resistance.Capsular polysaccharides(CPS)are major virulence determinants of pathogenic bacteria and have attracted ...Acinetobacter baumannii infections pose a great threat to public health owing to upsurging antibiotic resistance.Capsular polysaccharides(CPS)are major virulence determinants of pathogenic bacteria and have attracted much attention as potential targets for vaccine development.However,the obtainability of structurally well-defined CPS-related oligosaccharides remains challenging.Herein,we report an efficient chemoenzymatic strategy for the first total synthesis of common CPS pentasaccharide repeating unit of Acinetobacter baumannii K27 and K44,containing a difficult-to-constructα-linked 5,7-di-N-acetyllegionaminic acid(Leg5,7Ac_(2))residue.The chemical synthesis of a branched tetrasaccharide precursor was accomplished by flexible orthogonal protecting-group manipulations and stereocontrolled glycosylations.Furthermore,the enzyme-catalyzed stereoselective installment of legionaminic acid residue into the tetrasaccharide,using one-pot multienzyme(OPME)synthesis system to produce sugar nucleotide CMP-Leg5,7diN_(3) and subsequentα2,6-sialyltransferase-catalyzed glycosylation,was achieved to synthesize the pentasaccharide.展开更多
Comprehensive Summary Terpyridine ligands have been applied as a class of unique ligands due to their rich coordination chemistry in the catalysis.Herein,we developed a new class of C_(2)-symmetric chiral terpyridine-...Comprehensive Summary Terpyridine ligands have been applied as a class of unique ligands due to their rich coordination chemistry in the catalysis.Herein,we developed a new class of C_(2)-symmetric chiral terpyridine-pyrroloimidazolone ligands(TPy-BPI).Their catalytic activity was evaluated in the asymmetric Friedel-Crafts alkylation of indoles with 2,3-dioxopyrrolidines.Excellent yields(up to 92%)and high enantioselectivities(up to 97%ee)are obtained for a wide range of substrates under mild conditions.展开更多
Semiconductor photocatalytic technology has become one of the most important means to solve the current energy shortage and environmental pollution. Compared with the traditional photocatalysts, graphite carbon nitrid...Semiconductor photocatalytic technology has become one of the most important means to solve the current energy shortage and environmental pollution. Compared with the traditional photocatalysts, graphite carbon nitride has a wider range of light-harvesting and more stable physical and chemical properties. However, traditional thermally induced polymerization of nitrogen-containing precursors produces the melon-based carbon nitride solids with an amorphous or semi-crystalline structure, resulting in low conductivity and moderate photocatalytic activity. Recently, crystalline carbon nitride has attracted more and more attention in improving photocatalytic performance. Some significant progress regarding crystalline carbon nitride for the preparation of solar-fuel and environmental purification has also been made.This review describes the recent advances in the design and synthesis of crystalline carbon nitride photocatalysts. A brief description of the unique physical and chemical properties of crystalline carbon nitride was given. Later, the synthetic and modification strategies are being introduced. Then, the photocatalytic application of crystalline carbon nitride was discussed, mainly including photocatalytic H2 production,photocatalytic CO2 reduction, and photocatalytic degradation of pollutants. Finally, the challenges and future directions of crystalline carbon nitride photocatalysts are briefly introduced.展开更多
Sodium-ion batteries(SIBs)present great appeal in various energy storage systems,especifically for stationary grid storage,on account of the abundance of sources and low cost.Unfortunately,the commercialization of SIB...Sodium-ion batteries(SIBs)present great appeal in various energy storage systems,especifically for stationary grid storage,on account of the abundance of sources and low cost.Unfortunately,the commercialization of SIBs is mainly limited by available electrode materials,especially for the cathodes.Prussian blue analogs(PBAs),emerge as a promising alternative for their structural feasibility in the application of SIBs.Decreasing the defects(vacancies and coordinated water)is an effective strategy to achieve superior electrochemical performance during the synthetic processes.Herein,we summarize crystal structures,synthetic methods,electrochemical mechanisms,and the influences of synthesis conditions of PBAs in detail.This comprehensive overview on the current research progresses of PBAs will give guides and directions to solve the existing problems for their application in SIBs.展开更多
Covalent organic frameworks(COFs)are an emerging type of porous crystalline polymers formed by combining strong covalent bonds with organic building blocks.Due to their large surface area,high intrinsic pore space,goo...Covalent organic frameworks(COFs)are an emerging type of porous crystalline polymers formed by combining strong covalent bonds with organic building blocks.Due to their large surface area,high intrinsic pore space,good crystallization properties,high stability,and designability of the resultant units,COFs are widely studied and used in the fields of gas adsorption,drug transport,energy storage,photoelectric catalysis,electrochemistry,and sensors.In recent years,the rapid development of the Internet of Things and people’s yearning for a better life have put forward higher and more requirements for sensors,which are the core components of the Internet of Things.Therefore,this paper reviews the recent progress of COFs in synthesis methods and sensing applications,especially in the last five years.This paper first introduces structure,properties,and synthesis methods of COFs and discusses advantages and disadvantages of different synthesis methods.Then,the research progress of COFs in different sensing fields,such as metal ion sensors,gas sensors,biomedical sensors,humidity sensors,and pH sensors,is introduced systematically.Conclusions and prospects are also presented in order to provide a reference for researchers concerned with COFs and sensors.展开更多
Amorphous nanomaterials are metastable nanomaterials which only have short-range order within a few neighboring atoms,based on the local chemical bondings.Different from crystalline materials,the amorphous nanomateria...Amorphous nanomaterials are metastable nanomaterials which only have short-range order within a few neighboring atoms,based on the local chemical bondings.Different from crystalline materials,the amorphous nanomaterials lack of long-range order exhibit many intriguing and unique structu ral features,such as abundant active sites,structural flexibility,intrinsic isotropy and fast ionic transport.However,due to the unco nventional structural complexity,the systematic study and understanding of amorphous nanomaterials are still in the early stage.In this review,we will describe our journey to the synthesis,characterization and applications of amorphous nanomaterials,including catalysis,energy storage,optics and mechanics.展开更多
The successful approval of peptide-based drugs can be attributed to a collaborative effort across multiple disciplines.The integration of novel drug design and synthesis techniques,display library technology,delivery ...The successful approval of peptide-based drugs can be attributed to a collaborative effort across multiple disciplines.The integration of novel drug design and synthesis techniques,display library technology,delivery systems,bioengineering advancements,and artificial intelligence have significantly expedited the development of groundbreaking peptide-based drugs,effectively addressing the obstacles associated with their character,such as the rapid clearance and degradation,necessitating subcutaneous injection leading to increasing patient discomfort,and ultimately advancing translational research efforts.Peptides are presently employed in the management and diagnosis of a diverse array of medical conditions,such as diabetes mellitus,weight loss,oncology,and rare diseases,and are additionally garnering interest in facilitating targeted drug delivery platforms and the advancement of peptide-based vaccines.This paper provides an overview of the present market and clinical trial progress of peptide-based therapeutics,delivery platforms,and vaccines.It examines the key areas of research in peptide-based drug development through a literature analysis and emphasizes the structural modification principles of peptide-based drugs,as well as the recent advancements in screening,design,and delivery technologies.The accelerated advancement in the development of novel peptide-based therapeutics,including peptide-drug complexes,new peptide-based vaccines,and innovative peptide-based diagnostic reagents,has the potential to promote the era of precise customization of disease therapeutic schedule.展开更多
Earth rover is a class of emerging wheeled-leg robots for nature exploration.At present,few methods for these robots’leg design utilize a side-mounted spatial parallel mechanism.Thus,this paper presents a complete de...Earth rover is a class of emerging wheeled-leg robots for nature exploration.At present,few methods for these robots’leg design utilize a side-mounted spatial parallel mechanism.Thus,this paper presents a complete design process of a novel 5-degree-of-freedom(5-DOF)hybrid leg mechanism for our quadruped earth rover BJTUBOT.First,a general approach is proposed for constructing the novel leg mechanism.Subsequently,by evaluating the basic locomotion task(LT)of the rover based on screw theory,we determine the desired motion characteristic of the sidemounted leg and carry out its two feasible configurations.With regard to the synthesis method of the parallel mechanism,a family of concise hybrid leg mechanisms using the 6-DOF limbs and an L1F1C limb(which can provide a constraint force and a couple)is designed.In verifying the motion characteristics of this kind of leg,we select a typical(3-UPRU&RRRR)&R mechanism and then analyze its kinematic model,singularities,velocity mapping,workspace,dexterity,statics,and kinetostatic performance.Furthermore,the virtual quadruped rover equipped with this innovative leg mechanism is built.Various basic and specific LTs of the rover are demonstrated by simulation,which indicates that the flexibility of the legs can help the rover achieve multitasking.展开更多
基金the financial support from the Research Institute for Artificial Intelligence of Things(RIAIoT)the Research Institute for Advanced Manufacturing(RIAM)+1 种基金the Research Institute for Intelligent Wearable Systems(RI-IWEAR)the Research Centre of Textiles for Future Fashion(RCTFF)at the Hong Kong Polytechnic University。
文摘Reconfigurable parallel mechanisms were first discovered in response to the growing demand for flexible and adaptive systems in various fields.Unlike traditional mechanisms,which are designed for specific tasks and have fixed topology and mobility characteristics,a reconfigurable parallel mechanism can be adapted to different situations by changing its structure,motion,and function.This adaptability enables a single mechanism to perform a wide range of tasks,reducing the need for multiple dedicated systems.This paper presents a comprehensive review of reconfigurable parallel mechanisms.The characteristics of their designs,analyses of their properties,and challenges they face are reported.The beginning of this paper features an introduction of reconfigurable parallel mechanisms and their classification into different types.Methods for synthesizing reconfigurable parallel mechanisms are discussed.A performance evaluation index related to reconfigurability,workspace,singularity,stiffness,and dynamics,among other indices,is presented.This review covers the challenges faced in the creation of systematic design theories,unified performance analyses,evaluation index systems,and in the implementation of reconfigurable parallel mechanisms,such as the development of efficient control strategies and integration with other technologies.The paper concludes with a discussion of future research directions for reconfigurable parallel mechanisms.
基金the National Natural Science Foundation of China(Nos.31070386,21302195 and 31300290)135 Key Cultivation Program of the Chinese Academy of Sciencesthe Province-Academy Cooperation Program of Henan Province of China(No.102106000021)for financial support
文摘The presence of hydroxyl groups at the C4 and C7 positions in coumarin backbone has been proposed as a potential modification site for providing excellent bioactivity according to previous studies. A series of novel coumarin derivatives were rationally designed and synthesized by use of a complex catalytic system for a targeted modification at the above sites. These derivatives were assayed for nematicidal activity. As predicted, the derivatization enhanced the activity of the coumarins against five nematodes.Compounds 7b, 9a, 10 c and 11 c showed significant strong nematicidal broad spectrum activity against all tested nematodes. Compound 10 c was the most effective with the lowest LC50 values against Meloidogyne incognita（5.1 mmol/L）, Ditylenchus destructor（3.7 mmol/L）, Bursaphelenchus mucronatus（6.4 mmol/L）, Bursaphelenchus B. xylophilus（2.5 mmol/L） and Aphelenchoides besseyi（3.1 mmol/L）,respectively. A brief investigation on the structure–activity relationships（SAR） revealed that the targeted modification by a C7 hydroxyl was optimum compared with that of a C4 hydroxyl and that the coupling chain length was crucial for the nematicidal activity.
基金Supported by the Program for Changjiang Scholars and Innovative Research Team in Universities(No: IRT0422) and the Spe-cial Funds for Major State Basic Research Projects(No. G1999064803).
文摘A series of transparent ABS（T-ABS） resins were prepared by emulsion in situ suspension polymerization. The influences of the particle size and the content of rubber particles on the transparency of T-ABS resins were studied by varying the size and content of rubber particles in a single model system（rubber particles with a uniform size）. The optical properties of T-ABS resins were investigated in a mixed system of SBR/PB particles and a hi-modal particle system（rubber particles with two different sizes, 70 and 400 nm in diameter） of SBR particles. It was found that when the size of the smaller particles （ 70 nm） in the mixed system of SBR/PB particles was in the range of 50-100 nm in diameter, the T-ABS resins showed a better transparency. These results provide a flexible and practical process for the preparation of T-ABS resins with good optical and mechanical properties.
基金supported by the National Natural Science Foundation of China(22179041)。
文摘High voltage is necessary for high energy lithium-ion batteries but difficult to achieve because of the highly deteriorated cyclability of the batteries.A novel strategy is developed to extend cyclability of a high voltage lithium-ion battery,LiNi_(0.5)Mn_(1.5)O_(4)/Graphite(LNMO/Graphite)cell,which emphasizes a rational design of an electrolyte additive that can effectively construct protective interphases on anode and cathode and highly eliminate the effect of hydrogen fluoride(HF).5-Trifluoromethylpyridine-trime thyl lithium borate(LTFMP-TMB),is synthesized,featuring with multi-functionalities.Its anion TFMPTMB-tends to be enriched on cathode and can be preferentially oxidized yielding TMB and radical TFMP-.Both TMB and radical TFMP can combine HF and thus eliminate the detrimental effect of HF on cathode,while the TMB dragged on cathode thus takes a preferential oxidation and constructs a protective cathode interphase.On the other hand,LTFMP-TMB is preferentially reduced on anode and constructs a protective anode interphase.Consequently,a small amount of LTFMP-TMB(0.2%)in 1.0 M LiPF6in EC/DEC/EMC(3/2/5,wt%)results in a highly improved cyclability of LNMO/Graphite cell,with the capacity retention enhanced from 52%to 80%after 150 cycles at 0.5 C between 3.5 and 4.8 V.The as-developed strategy provides a model of designing electrolyte additives for improving cyclability of high voltage batteries.
基金supported by the Fundamental Research Grant Scheme by Ministry of Higher Education Malaysia(FRGS/1/2021/STG04/XMU/02/1 and FRGS/1/2022/TK09/XMU/03/2)the Xiamen University Malaysia Research Fund(XMUMRF/2023-C11/IENG/0056)。
文摘MXene has been the limelight for studies on electrode active materials,aiming at developing supercapacitors with boosted energy density to meet the emerging influx of wearable and portable electronic devices.Despite its various desirable properties including intrinsic flexibility,high specific surface area,excellent metallic conductivity and unique abundance of surface functionalities,its full potential for electrochemical performance is hindered by the notorious restacking phenomenon of MXene nanosheets.Ascribed to its two-dimensional(2D)nature and surface functional groups,inevitable Van der Waals interactions drive the agglomeration of nanosheets,ultimately reducing the exposure of electrochemically active sites to the electrolyte,as well as severely lengthening electrolyte ion transport pathways.As a result,energy and power density deteriorate,limiting the application versatility of MXene-based supercapacitors.Constructing 3D architectures using 2D nanosheets presents as a straightforward yet ingenious approach to mitigate the fatal flaws of MXene.However,the sheer number of distinct methodologies reported,thus far,calls for a systematic review that unravels the rationale behind such 3D MXene structural designs.Herein,this review aims to serve this purpose while also scrutinizing the structure–property relationship to correlate such structural modifications to their ensuing electrochemical performance enhancements.Besides,the physicochemical properties of MXene play fundamental roles in determining the effective charge storage capabilities of 3D MXene-based electrodes.This largely depends on different MXene synthesis techniques and synthesis condition variations,hence,elucidated in this review as well.Lastly,the challenges and perspectives for achieving viable commercialization of MXene-based supercapacitor electrodes are highlighted.
文摘The vapor recompression heat pump(VRHP) distillation technology offers significant improvements in energy efficiency for distillation systems with small temperature differences between the top and bottom of the column. However, the separation of wide-boiling binary mixtures leads to substantial temperature differences between the top and bottom of the column. This limits the applicability of conventional VRHP due to high capital costs and strict performance requirements of the compressor. To overcome these challenges and to accommodate compressor operating conditions, a novel synthesis and design method is introduced to integrate VRHPs with wide-boiling binary mixture distillation columns(WBMDCs). This method enables quick determination of an initial configuration for the integrated WBMDC-VRHP system and helps identify the optimum configuration with the minimum total annual cost. Two examples, namely the separation of benzene/toluene and isopropanol/chlorobenzene, are employed to derive optimum configurations of the WBMDC-VRHP and compare them with the WBMDC. A systematic comparison between the WBMDC-VRHP and WBMDC demonstrates the superior steady-state performance and economic efficiency of the WBMDC-VRHP.
文摘Curcumin (curcumin 1, 7-double (4-hydroxy-3-methoxyphenyl) -1, 6-hepadiene-3, 5-diketone) is a natural compound containing dione structure (C21H20O6), with anti-cancer, anti-inflammatory, antibacterial, anti-virus, anti-infection and other pharmacological activities. In recent years, the domestic and foreign scientists to its structure of the modified compound research results emerge one after another. In this paper, the design and synthesis of curcumin analogues and their antibacterial activities were reviewed, which provided a reference for the study of new curcumin analogues and their antibacterial activities.
基金supported by the CASHIPS Director’s Fund (Grant No. YZJJ202207-CX)。
文摘Polymeric nitrogen is a potential high-energy-density material with the advantages of high energy density, easy availability of raw materials, and non-pollution. The design and synthesis of polymeric nitrogen are important in the research field of energetic materials. The cubic gauche nitrogen was successfully synthesized at high pressure in the diamond anvil cell, which stimulated the theoretical and experimental investigations. To date, several hundred kinds of polymeric nitrogen have been reported. This review introduces the progressive development of polymeric nitrogen with high energy density, the challenges faced by the synthesized polymeric nitrogen under high-pressure,and the importance to improve the stability of polymeric nitrogen at ambient pressure. Furthermore, alternative methods for synthesizing polymeric nitrogen under moderate conditions are also presented. In this field, more efforts are needed to develop strategies for stabilizing more polymeric nitrogen to ambient conditions, especially the stability of free surfaces.
基金financially supported by the NSFC (Nos. 21322601, 21271015, 21406006, and U1407119)Program for New Century Excellent Talents in University (No. NCET-13-0647)
文摘Two new metal-organic frameworks（MOFs）,[Cu2（H_2O）_2（BCPIA）]（BUT-20）and（Me_2NH_2）[In（BCPIA）]（BUT-21）were designed and synthesized through the solvothermal reaction between a newly created desymmetric 4-connected ligand,5-（2,6-bis（4-carboxyphenyl）pyridin-4-yl）isophthalic acid（H_4BCPIA）and Cu（NO_3）2 2.5H_2O or In（NO_3）_3·5H_2O,respectively,and characterized by single-crystal and powder Xray diffraction,thermogravimetric analysis,infrared spectroscopy,and elemental analysis.The two MOFs have three-dimensional structures,in which both the BCPIA 4 ligand and metal-containing entities,Cu_2（COO）_4（H_2O）_2 and In（COO）_4 act as 4-connected nodes.However,different linkage configurations of the two metal-containing nodes,quadrilateral Cu_2_TD_2（COO）_4（H_2O）_2and tetrahedral In（COO）_4,lead to distinct structural networks of BUT-20 and 21,with Nbo and Unc topologies,respectively.
基金Supported by the 973 Program (2007CB815301 and 2006CB932904)the National Natural Science Foundation of China (20333070, 20871114 and 20673118)+1 种基金the Science Foundation of CAS (KJCX2-YW-M05)Fujian Province (2006F3132 and 2007J0171)
文摘Two cyanide bridged trinuclear compounds [Fe（bpy）2（CN）2]·[Cu（Cyclam）]2（ClO4）4·DMF 1 and [Fe（Phen）2（CN）2]·[Cu（Cyclam）]2（ClO4）4·2CH3CN·4H2O 2 （Bpy = 2,2＇- bipyridine, Phen = 1,10-phenanthroline, Cyclam = 1,4,8,11-tetraaza-cyclotetradecane, and DMF = N,N-dimethylformamide） have been synthesized by using mononuclear [Fe（Phen）2（CN）2]·2H2O and [Fe（bpy）2（CN）2]·3H2O as precursors. These two complexes crystallize in monoclinic space groups P21/c and C2/c, respectively. For 1, a = 25.164（2）, b = 12.0405（11）, c = 20.4433（15） A, β = 91.948（3）°, V = 6190.5（9） A^3, Z = 4, Mr = 1418.90, Dc = 1.522 g/cm^3, F（000） = 2936, μ = 1.161 mm^-1, the final R = 0.0722 and wR = 0.2011 for 10779 observed reflections （I 〉 2σ（I））. For 2, a = 43.5945（0）, b = 11.8447（0）, c = 29.5637（2）A, β = 120.430（11）o, V = 13162.76（9） A^3, Z = 8, Mr = 1518.48, Dc = 1.533 g/cm^3, F（000） = 6288, μ = 1.101 mm^-1, the final R = 0.0711 and wR = 0.1783 for 11262 observed reflections （I 〉 2σ（I））.
文摘Today＇s manufacturing cnvironmem forces manufacturing companies to make as many product variations as possible at affordable costs within a short time. Mass customisation is one of most important technologies for companies to achieve their objectives. Efforts to mass customisation should be made on two aspects： （1） To modularize products and make them as less differences as possible; （2） To design manufacturing resources and make them provide as many processes variations as possible. This paper reports our recent work on aspect （2）, i.e. how to design a reconfignrable manufacturing system （RMS） so that it can be competent to accomplish various processes optimally; Reconfignrable robot system （RRS） is taken as an example. RMS design involves architecture design and configuration design, and configuration design is further divided in design analysis and design synthesis. Axiomatic design theory （ADT） is applied to architecture design, the features and issues of RRS configuration design are discussed, automatic modelling method is developed for design analysis, and concurrent design methodology is presented for design synthesis.
基金supported by the National Key Research and Development Program of China(Grant No.2021YFE0205900)the Key Technologies R&D Program of Jiangsu(Prospective and Key Technologies for Industry)(Grant Nos.BE2022067 and BE2022067-2)。
文摘In this article,studies on the multimode excitation problem of waveguides and antennas,the balance/unbalance mech-anism and the balanced feeding techniques in dipole antenna systems are first briefly historically reviewed.In this context,general-ized odd-even mode theory is advanced to quantitatively and approximately describe the mutual coupling effect between a feed line and an antenna.As is mathematically deduced and demonstrated,the modal parity mismatch between the feed line and the antenna should ultimately dominate the unbalance phenomenon in antenna systems.Thus,an elegant,closed-form formula is derived to ap-proximately calculate the“unbalance degree”of a straight dipole off-center fed by a symmetric twin-wire line.Design approaches for the simplest,linear,1-D multimode resonant antennas are introduced.Moreover,the“falling tone excitation”law gauged based on prototype dipoles is revealed and used to develop a mode synthesis design approach for microstrip patch antennas(MPAs)and 2-D sectorial electric dipole antennas.Design examples with distinctive radiation performance are presented and discussed.Finally,possible development trends of multimode resonant antennas are prospected.
基金financially supported by the National Natural Science Foundation of China(22077130 and 22377134)Shanghai Municipal Science and Technology Major Project.
文摘Acinetobacter baumannii infections pose a great threat to public health owing to upsurging antibiotic resistance.Capsular polysaccharides(CPS)are major virulence determinants of pathogenic bacteria and have attracted much attention as potential targets for vaccine development.However,the obtainability of structurally well-defined CPS-related oligosaccharides remains challenging.Herein,we report an efficient chemoenzymatic strategy for the first total synthesis of common CPS pentasaccharide repeating unit of Acinetobacter baumannii K27 and K44,containing a difficult-to-constructα-linked 5,7-di-N-acetyllegionaminic acid(Leg5,7Ac_(2))residue.The chemical synthesis of a branched tetrasaccharide precursor was accomplished by flexible orthogonal protecting-group manipulations and stereocontrolled glycosylations.Furthermore,the enzyme-catalyzed stereoselective installment of legionaminic acid residue into the tetrasaccharide,using one-pot multienzyme(OPME)synthesis system to produce sugar nucleotide CMP-Leg5,7diN_(3) and subsequentα2,6-sialyltransferase-catalyzed glycosylation,was achieved to synthesize the pentasaccharide.
基金the financial support from the NSFC(22061006)Key Laboratory of Applied Surface and Colloid Chemistry(Shaanxi Normal University)of Ministry of Education,Natural Science Basic Research Plan in Shaanxi Province of China(No.2024JC-YBMS-119)+1 种基金Key Research and Development Plan Project of Xianyang(L2023-ZDYF-QYCX-030)Guizhou Provincial Basic Research Program(GCC[2023]078,ZK[2023]043,ZK[2022]144).
文摘Comprehensive Summary Terpyridine ligands have been applied as a class of unique ligands due to their rich coordination chemistry in the catalysis.Herein,we developed a new class of C_(2)-symmetric chiral terpyridine-pyrroloimidazolone ligands(TPy-BPI).Their catalytic activity was evaluated in the asymmetric Friedel-Crafts alkylation of indoles with 2,3-dioxopyrrolidines.Excellent yields(up to 92%)and high enantioselectivities(up to 97%ee)are obtained for a wide range of substrates under mild conditions.
基金supported by the National Natural Science Foundation of China (No. 51672099)the Sichuan Science and Technology Program (Nos. 2021JDTD0026)the Fundamental Research Funds for the Central Universities (No. 2017-QR-25)。
文摘Semiconductor photocatalytic technology has become one of the most important means to solve the current energy shortage and environmental pollution. Compared with the traditional photocatalysts, graphite carbon nitride has a wider range of light-harvesting and more stable physical and chemical properties. However, traditional thermally induced polymerization of nitrogen-containing precursors produces the melon-based carbon nitride solids with an amorphous or semi-crystalline structure, resulting in low conductivity and moderate photocatalytic activity. Recently, crystalline carbon nitride has attracted more and more attention in improving photocatalytic performance. Some significant progress regarding crystalline carbon nitride for the preparation of solar-fuel and environmental purification has also been made.This review describes the recent advances in the design and synthesis of crystalline carbon nitride photocatalysts. A brief description of the unique physical and chemical properties of crystalline carbon nitride was given. Later, the synthetic and modification strategies are being introduced. Then, the photocatalytic application of crystalline carbon nitride was discussed, mainly including photocatalytic H2 production,photocatalytic CO2 reduction, and photocatalytic degradation of pollutants. Finally, the challenges and future directions of crystalline carbon nitride photocatalysts are briefly introduced.
基金National Natural Science Foundation of China,Grant/Award Numbers:51971124,52171217。
文摘Sodium-ion batteries(SIBs)present great appeal in various energy storage systems,especifically for stationary grid storage,on account of the abundance of sources and low cost.Unfortunately,the commercialization of SIBs is mainly limited by available electrode materials,especially for the cathodes.Prussian blue analogs(PBAs),emerge as a promising alternative for their structural feasibility in the application of SIBs.Decreasing the defects(vacancies and coordinated water)is an effective strategy to achieve superior electrochemical performance during the synthetic processes.Herein,we summarize crystal structures,synthetic methods,electrochemical mechanisms,and the influences of synthesis conditions of PBAs in detail.This comprehensive overview on the current research progresses of PBAs will give guides and directions to solve the existing problems for their application in SIBs.
基金funded by the National Natural Science Foundation of China(No.21964016)Xinjiang National Science Fund for Distinguished Young Scholars(No.2022D01E37)+1 种基金Key programs of Xinjiang Natural Science Foundation(No.2022B02051)Tianshan Innovation Team Program of Xinjiang Uygur Autonomous Region(No.2020D14038).
文摘Covalent organic frameworks(COFs)are an emerging type of porous crystalline polymers formed by combining strong covalent bonds with organic building blocks.Due to their large surface area,high intrinsic pore space,good crystallization properties,high stability,and designability of the resultant units,COFs are widely studied and used in the fields of gas adsorption,drug transport,energy storage,photoelectric catalysis,electrochemistry,and sensors.In recent years,the rapid development of the Internet of Things and people’s yearning for a better life have put forward higher and more requirements for sensors,which are the core components of the Internet of Things.Therefore,this paper reviews the recent progress of COFs in synthesis methods and sensing applications,especially in the last five years.This paper first introduces structure,properties,and synthesis methods of COFs and discusses advantages and disadvantages of different synthesis methods.Then,the research progress of COFs in different sensing fields,such as metal ion sensors,gas sensors,biomedical sensors,humidity sensors,and pH sensors,is introduced systematically.Conclusions and prospects are also presented in order to provide a reference for researchers concerned with COFs and sensors.
基金supported by the National Natural Science Foundation of China(Nos.51532001,52272181 and 51872016).
文摘Amorphous nanomaterials are metastable nanomaterials which only have short-range order within a few neighboring atoms,based on the local chemical bondings.Different from crystalline materials,the amorphous nanomaterials lack of long-range order exhibit many intriguing and unique structu ral features,such as abundant active sites,structural flexibility,intrinsic isotropy and fast ionic transport.However,due to the unco nventional structural complexity,the systematic study and understanding of amorphous nanomaterials are still in the early stage.In this review,we will describe our journey to the synthesis,characterization and applications of amorphous nanomaterials,including catalysis,energy storage,optics and mechanics.
基金supported by the Natural Science Foundation of China(No.82073311)Science&Technology Department of Sichuan Province Individualized Drug Therapy Small Molecule Innovative Drugs Sichuan Youth Science and Technology Innovation Research Team(No.2022JDTD0025)Sichuan Traditional Chinese Medicine Administration(No.2023MS026).
文摘The successful approval of peptide-based drugs can be attributed to a collaborative effort across multiple disciplines.The integration of novel drug design and synthesis techniques,display library technology,delivery systems,bioengineering advancements,and artificial intelligence have significantly expedited the development of groundbreaking peptide-based drugs,effectively addressing the obstacles associated with their character,such as the rapid clearance and degradation,necessitating subcutaneous injection leading to increasing patient discomfort,and ultimately advancing translational research efforts.Peptides are presently employed in the management and diagnosis of a diverse array of medical conditions,such as diabetes mellitus,weight loss,oncology,and rare diseases,and are additionally garnering interest in facilitating targeted drug delivery platforms and the advancement of peptide-based vaccines.This paper provides an overview of the present market and clinical trial progress of peptide-based therapeutics,delivery platforms,and vaccines.It examines the key areas of research in peptide-based drug development through a literature analysis and emphasizes the structural modification principles of peptide-based drugs,as well as the recent advancements in screening,design,and delivery technologies.The accelerated advancement in the development of novel peptide-based therapeutics,including peptide-drug complexes,new peptide-based vaccines,and innovative peptide-based diagnostic reagents,has the potential to promote the era of precise customization of disease therapeutic schedule.
基金supported by the National Natural Science Foundation of China(Grant No.52275004).
文摘Earth rover is a class of emerging wheeled-leg robots for nature exploration.At present,few methods for these robots’leg design utilize a side-mounted spatial parallel mechanism.Thus,this paper presents a complete design process of a novel 5-degree-of-freedom(5-DOF)hybrid leg mechanism for our quadruped earth rover BJTUBOT.First,a general approach is proposed for constructing the novel leg mechanism.Subsequently,by evaluating the basic locomotion task(LT)of the rover based on screw theory,we determine the desired motion characteristic of the sidemounted leg and carry out its two feasible configurations.With regard to the synthesis method of the parallel mechanism,a family of concise hybrid leg mechanisms using the 6-DOF limbs and an L1F1C limb(which can provide a constraint force and a couple)is designed.In verifying the motion characteristics of this kind of leg,we select a typical(3-UPRU&RRRR)&R mechanism and then analyze its kinematic model,singularities,velocity mapping,workspace,dexterity,statics,and kinetostatic performance.Furthermore,the virtual quadruped rover equipped with this innovative leg mechanism is built.Various basic and specific LTs of the rover are demonstrated by simulation,which indicates that the flexibility of the legs can help the rover achieve multitasking.
