Superfast and solvent-free core-shell assembly of sulfur/carbon active particles by hail-inspired nanostorm technology for high-energy-density Li-S batteries

The demand on low-carbon emission fabrication technologies for energy storage materials is increasing dramatically with the global interest on carbon neutrality.As a promising active material for metal-sulfur batteries,sulfur is of great interest due to its high-energy-density and abundance.However,there is a lack of industry-friendly and low-carbon fabrication strategies for high-performance sulfur-based active particles,which,however,is in critical need by their practical success.Herein,based on a hail-inspired sulfur nano-storm(HSN)technology developed in our lab,we report an energy-saving,solvent-free strategy for producing core-shell sulfur/carbon electrode particles(CNT@AC-S)in minutes.The fabrication of the CNT@AC-S electrode particles only involves low-cost sulfur blocks,commercial carbon nanotubes(CNT)and activated carbon(AC)micro-particles with high specific surface area.Based on the above core-shell CNT@AC-S particles,sulfur cathode with a high sulfur-loading of 9.2 mg cm^(-2) delivers a stable area capacity of 6.6 mAh cm^(-2) over 100 cycles.Furthermore,even for sulfur cathode with a super-high sulfur content(72 wt%over the whole electrode),it still delivers a high area capacity of 9 mAh cm^(-2) over50 cycles in a quasi-lean electrolyte condition.In a nutshell,this study brings a green and industryfriendly fabrication strategy for cost-effective production of rationally designed S-rich electrode particles.

Dissipative Particle Dynamics Simulations of the Self-assembly Mechanisms of Fluorinated Ordered Mesoporous Carbon in the Aqueous Phase

To clarify the preparation mechanisms of uorinated ordered mesoporous carbon materials (FOMCs), the dissipative par- ticle dynamics method was used to simulate the self-assembly process of the amphiphilic triblock poly(ethylene oxide)- poly(propylene oxide)-poly(ethylene oxide) copolymer Pluronic F127 in the aqueous system. The self-assembly mechanisms in aqueous phase and the formation mechanisms of micropores and mesopores were investigated. It was found that the mesoporous structure of the FOMCs was formed by the hydrophobic segments of F127, while the pore wall was formed by both the hydrophilic segments and the carbon precursor in the system. The microporous structure on the pore wall was con- structed by the carbon source in the hydrophilic segments’ spaces after the template was removed. Our ndings could provide understanding and knowledge for the synthesis of mesoporous carbon by the self-assembly method on the mesoscopic scale.

Characterization of self-assembled nano-phase silane-based particle coating

Self-assembled nano-phase silane-based particle coating was prepared through sol-gel technique.Tetramethoxysilane and 3-glycidoxypropyltrimethoxysilane were used as precursors for the self-assembled sol-gel coatings.The silane colloidal particle size was analyzed by laser particle size measurement.The results indicate that the particle size is in nano-scale and the diameter of particles deceases with increasing dilution times.Gel permeation chromatography proves that the relative molecular mass of macromolecule in a referenced sol solution is 1220-1240 amu.A simulation model was proposed to study the siloxane structure.Fourier transform infrared spectra of solution and film prove the disappearing of epoxy bond.The results of solid-state 13C and 29Si nuclear magnetic resonance experiments indicate the formation of Si-O-Si network.Potentiodynamic analysis shows that the self-assembled coating has excellent corrosion resistance.Salt fog tests prove that 2-methyl piperidine as inhibitor significantly improves the corrosion resistance of the self-assembled coating.

Hydrophobic nanochannel self-assembled by amphipathic Janus particles confined in aqueous nano-space

Hydrophobic nanochannel plays a significant role in many physical, biological, and geological phenomena and ex- hibits impressive applications due to both its ubiquitous distribution and great ability to transport hydrophobic molecules, including various oils and gases. Based on theoretical modeling, we herein reveal that the amphipathic Janus nanoparticles have a large probability to self-assemble into uninterrupted hydrophobic nanochannels inside the aqueous nano-space, al- though there are large portions of the Janus nanoparticles to be hydrophilic. The key to this observation is the attractions between the hydrophobic regimes on neighboring amphipathic Janus particles through hydrophobic interaction in aqueous nano-space. More surprisingly, the permeation efficiency of hydrophobic molecules through the uninterrupted hydrophobic channel in Janus particles aggregate is even higher than that in the aggregate of hydrophobic particles. We note that the proposed amphipathic Janus particles can be transported to the appropriate positions by the water since the hydrophilic regimes still remain a strong particle-water interaction. We also note that most natural subsurface rocks are not completely hydrophobic or hydrophilic but have complex surfaces with inhomogeneous wetting property. Our work therefore provides a detailed molecular level understanding of the formation of underground strata as well as the new insight for constructing the artificial hydrophobic channels for various applications, such as the design of proppants to enhance the recovery of the unconventional oil/gas.

Conceptual design and neutronic analysis of a megawatt-level vehicular microreactor based on TRISO fuel particles and S-CO_(2) direct power generation

With global warming,the demand for diversified energy sources has increased significantly.Transportable microreactors are important potential supplements to the global power market and are a promising development direction.This paper describes a 5 MW integrated long-life S-CO_(2)cooled vehicular microreactor(VMR)design based on tristructural isotropic(TRISO)fuel particles that aims to provide electricity for industrial power facilities,remote mines,and remote mountainous areas that are not connected to central power grids.First,to facilitate transportation,flexible deployment,and simplified operation and maintenance requirements,the VMR core and auxiliary system were designed to be reasonably small and as simple as possible.Second,the TRISO fuel particles used in the proposed VMR offer excellent properties,such as high inherent security and nonproliferation,which are vital for reactors in remote areas.In addition,a long core lifetime was achieved using the compact core design and enhanced fuel loading capacity,which is challenging when using TRISO as fuel.Finally,to make the VMR economically competitive in terms of improved neutron performance and fuel efficiency compared to similar designs,large-size TRISO particles and tube-in-duct fuel assembly were utilized and different core configurations were schemed and simulated to obtain the design that best satisfied the proposed criteria.The lifetime and burnup in the final optimized VMR were satisfactory at 21 years and43.9 MWd/kgU,respectively,with an adequate shutdown margin and excellent safety parameters to ensure safe operation.

猪细小病毒病研究进展

猪细小病毒(Porcine parvovirus,PPV)是一种无囊膜DNA病毒,主要引起母猪繁殖障碍。该病毒在全世界广泛流行,我国猪场PPV感染率高达90%以上,给养猪业带来巨大经济损失。PPV经口、鼻传播,主要侵染猪的生殖器官,引起母猪的死胎、木乃伊胎和公猪的精液质量下降。临床采用接种疫苗的方式进行防控,起到了一定的效果。论文对病毒的基因组和蛋白特征、流行病学和疫苗研究进行综述,以期为PPV的基础研究和疫苗开发提供参考。

基于混合算法的飞机部件装配静态调度方法研究

飞机部件装配生产工艺流程复杂、生产周期长,如何制定高效的生产调度计划是急需解决的问题。分析了飞机部件装配的工艺流程,建立了飞机部件装配调度的约束条件,包括装配工序的先后约束和装配工装占用的约束,建立了飞机部件装配调度的目标函数,包括最小化拖期惩罚和最小化最大完工周期,对飞机部件装配调度问题进行了合理的假设和抽象,并建立了飞机部件装配调度模型。针对飞机部件装配静态调度问题,将粒子群算法和变邻域搜索算法进行了有效结合,设计了粒子群-变邻域搜索混合算法,并采用实例验证了该算法的有效性。

自控型粒子冲击钻井系统研制与现场试验

我国油气资源勘探开发中常规钻井技术在钻遇石英砂岩、燧石、高硅质砂岩、黄铁矿和火成岩等难钻地层时,面临“钻速慢、进尺短”的钻井瓶颈。为此,基于粒子高频冲击破岩原理,借鉴高层建筑混凝土配浆-注浆和常压混凝土储存方法,设计了双活塞换向机构、防粒子沉淀物料罐、动态回收储存装置、高效分离装置和2D/3D自动化监控系统,研制了1套自控型粒子冲击钻井系统,并在江沙X1井对其进行了现场试验。试验结果表明:该系统运行稳定可靠,粒子回收率达到98.7%,平均机械钻速15 m/h,与邻井同地层螺杆配PDC钻头钻进方式相比平均机械钻速提高1.52倍。所得结论可为深层及复杂坚硬地层钻井提速提供技术支撑。

基于自适应模拟退火优化算法的集合式电容器局放定位研究

集合式电容器内部局部放电问题可能导致绝缘介质破坏和设备故障。已有的局部放电检测技术在集合式电容器中受到电磁干扰的限制。为此,提出了一种自适应模拟退火粒子群超声定位方法。该方法结合超声检测法克服电磁干扰对定位精度的影响,通过对粒子群参数进行自适应优化,并应用模拟退火和轮盘赌策略进行优化。为检测该方法的效果,通过对比实验表明,该方法提高了定位的准确性和稳定性,为集合式电容器局部放电定位问题提供了有效的解决方案。

层状ABC星型三嵌段共聚物和纳米颗粒的自组装

采用耗散粒子动力学模拟方法研究了层状ABC星型三嵌段共聚物和纳米颗粒的协同自组装.主要考虑了不同密度下纳米颗粒的聚集行为及其对层状结构的影响.当纳米颗粒密度较低时,纳米颗粒呈囊泡状聚集;当纳米颗粒密度较高时,纳米颗粒呈柱状聚集.通过分析体系能量和共聚物链的回转半径研究了该动力学过程;通过界面张力的计算,对体系中微结构的力学性能进行了探索.这些发现不仅有助于人们了解复杂的嵌段共聚物,也可以为探索嵌段共聚物和纳米颗粒的微结构提供思路,对研究嵌段共聚物纳米复合材料的潜在应用提供帮助.

基于嵌入式技术的轻小型落地抱杆自动控制系统研究

该文在分析轻小型落地抱杆结构的基础上,设计基于嵌入式技术的轻小型落地抱杆自动控制系统框架,由基础数据单元采集轻小型落地抱杆运行数据后,控制单元的嵌入式主控制器调用变频调速控制程序实现起升电机运行速度的控制,通过模糊PID控制器实现吊钩负载转矩补偿控制,并利用粒子群算法对控制器参数作在线实时整定,通过CAN总线将控制指令下达给各工作机构,并利用以太网实现与远程控制中心的信息交互。实验结果表明,该系统可实现轻小型落地抱杆自动控制,控制后的阶跃响应曲线平滑、超调量低,控制时间短,输出的模拟电压曲线走势稳定、平滑度高,不存在振荡问题。

Polymersomes:From Macromolecular Self-Assembly to Particle Assembly

What is the most favorite and original chemistry developed in your research group?Ring-opening polymerization-induced self-assembly of N-carboxyanhydrides(NCA-PISA),and fusion-induced particle assembly(FIPA).How do you get into this specific field?Could you please share some experiences with our readers?NCA-PISA was developed to solve the biodegradability problem of nanoparticles by traditional PISA,while FIPA was inspired by nature.

Experimental investigation on flow characteristics in circular tube inserted with rotor-assembled strand using PIV

Rotor-assembled strand works as a typical tube insert to achieve heat transfer augmentation and scale inhibition in a heat exchanger.In this work, the PIV experiment regarding the flow fields in a circular tube inserted with rotor-assembled strand was conducted and the flow characteristics on transverse section and longitudinal section were analyzed.The results showed that swirling flow was produced in the tube inserted with rotors and it was particularly strong within the swing diameter of the rotor on the section that contains the rotor;the average turbulence intensity and the radial velocity were improved notably; the velocity vectors on the longitudinal section remained along the direction of a straight line; both the swirling flow and average turbulence intensity were higher for the rotor with three blades than for the rotor with two blades except that the radial velocity was approximate, but they were all reduced by enlarging the lead of the rotor.Characterization of the flow patterns in a circular tube contributes to understanding the heat transfer efficiency and scale inhibition performance of the rotor-assembled strand and provides guidance for its application.

Self-assembly of latex particles for colloidal crystals

Self-assembly of latex particles is of great importance for fabricating various functional colloidal crystals. In this paper, we review recent research on the self-assembly of latex particles for colloidal crystals, covering the assembly forces and various assembly approaches of latex particles, including self-assembly by gravity sedimentation, vertical deposition, physical confinement, electric field, and magnetic field. Furthermore, some simple methods for assembling latex particles such as spin coating, spray coating, and printing are also summarized.

Block Copolymer Colloidal Particles with Unique Structures through Three-dimensional Confined Assembly and Disassembly

Structured block copolymer(BCP) particles have gained increasing attention due to their potential applications in separation,catalysis, controlled release, and other fields. Three-dimensional(3D) confined assembly has been proved as a facile yet robust approach for generating BCP particles with controllable shapes and internal structures. In this feature article, we summarized the preparation of structured polymeric particles through 3D confined self-assembly of BCPs. The effects of interfacial interactions, degree of confinement,and additives on the shape and internal structure of BCP microparticles were comprehensively discussed. In addition, we highlighted the recent progress in using disassembly as a route to synthesize colloidal particles with unique structures. Two strategies were introduced in this part:(a) disassembling the discrete domains resulted in mesoporous microparticles;(b) disassembling the continuous domains led to the dissociation of microparticles into micelle-like nano-objects. The applications of the structured colloidal particles in photonic crystals,controlled release, and directed growth of inorganic materials were also presented. Finally, we discussed the current challenges and future opportunities in this promising area.

Expression and self-assembly of Heterocapsa circularisquama RNA virus-like particles synthesized in Pichia pastoris

Heterocapsa circularisquama RNA virus(HcRNAV) is the first single-stranded RNA virus to be characterized that infects dinoflagellates.The ability of HcRNAV coat protein(HcRNAV CP) to self-assemble into virus-like particles(VLPs) in vitro suggested that heterologous expression was possible,and that the VLPs might be ideal nanocontainers for the targeted delivery of genes and chemicals.In this paper,we report the expression of a codon-optimized HcRNAV 109 CP gene in Pichia pastoris and the production of self-assembled HcRNAV VLPs using large-scale fermentation.The HcRNAV 109 CP gene was synthesized according to the codon preference of P.pastoris and cloned into a pPICZA vector.The recombinant plasmid pPICZA-CPsyns was transformed into P.pastoris by electroporation.The resulting yeast colonies were screened by PCR and analyzed for protein expression by SDS polyacrylamide gel electrophoresis.After large-scale fermentation,the yield of HcRNAV CPsyns reached approximately 2.5 g L 1 within 4 d.The HcRNAV VLPs were purified using PEG precipitation followed by cesium chloride density gradient ultracentrifugation,and were subsequently analyzed using UV spectrophotometry and transmission electron microscopy.Fluorescence dye-labeled myoglobin was loaded into the cages of the HcRNAV VLPs and the encapsulation was confirmed by fluorescence spectroscopy.The results point to the possible utilization in pharmacology or nanotechnology of HcRNAV VLPs produced by P.pastoris fermentation.

PROGRESS IN THREE-DIMENSIONALLY ORDERED SELF-ASSEMBLY OF COLLOIDAL SiO2 PARTICLES

Three-dimensionally ordered self-assembly of monodispersed colloidal SiO2 particles involving a structure with periodic alternation of refractive indices represents an advanced field of particuology, colloidal chemistry, materials science, optical physics and information science. Study on such self-assembly not only lays the foundation for the development of advanced functional materials, but also is significant in understanding the principles of nano- and micro-scale processes. Recent progress in three-dimensionally ordered self-assembly of colloidal SiO2 particles is reviewed, inclusive of the authors investigations.

Fabrication of virus-like particles with strip-pattern surface：A two-step self-assembly approach

Spherical nanostructures with striped patterns on the surfaces resembling the essential structures of natural virus particles were constructed through a two-step self-assembly approach of polystyrene-boligo（acrylic acid）（PS-b-oligo-AA） and poly（γ-benzyI L-glutamate）-b-poly（ethylene glycol）（PBLG-bPEG） copolymer mixtures in solution.On the basis of difference in hydrophilicity and self-assembly properties of the two copolymers,the two-step self-assembly process is realized.It was found that PS-boligo-AA copolymers formed spherical aggregates by adding a certain amount of water into polymer solutions in the first step.In the second step,two polymer solutions were mixed and water was further added,inducing the self-assembly of PBLG-b-PEG on the surfaces of PS-b-oligo-AA spheres to form striped patterns.In-depth study was conducted for the indispensable defects of striped patterns which are dislocations and ＋1/2 disclinations.The influencing factors such as the mixing ratio of two copolymers and the added water content in the first step on the morphology and defects of the striped patterns were investigated.This work not only presents an idea to interpret mechanism of the cooperative self-assembly behavior,but also provides an effective approach to construct virus-like particles and other complex structures with controllable morphology.

微小磁性零件装配设备自动标定及误差补偿

为了实现微小磁性零件装配设备的精密装配任务,弥补加工误差和安装误差带来的系统精度损失,提出了一套自动标定及误差补偿方法。依照设备布置形式建立了不同模块的坐标系,提取影响装配精度的全部误差参数。根据导轨的位置关系建立了模块之间的运动转换模型,进而推导出基于装配任务的误差补偿模型。以设备中的机器视觉系统作为测量工具,同时设计专用标定板。通过观察各模块运动前后特征点的坐标变化对误差参数进行测量和辨识,并使用粒子群算法对参数进行了全局优化。基于开发的自动标定软件,在装配区域进行了标定和验证实验。实验结果表明,补偿后的系统开环控制精度在6μm以内,满足设备的装配精度需求。该方法为微小零件装配设备提供了自动化、高精度和高效率的标定方案。

Orientated-assembly of rod-like silica particles based on sandwich structure from the superhydrophobic template and the superhydrophilic substrates

The paper demonstrated a facile approach for the orientated assembly of the rod-like silica particles by sandwich structure from the combined effect of superhydrophobic template and the superhydrophilic substrates. The rod-like particles can be arranged in ring-like, square-like and etc from the confined effect of the template, which will produce an important insight for the oriented assembly ofanisotropic particles and the development of the novel functional materials and devices.