Case Retrieval Strategy of Turning Process Based on Grey Relational Analysis

To solve the problem of long response time when users obtain suitable cutting parameters through the Internet based platform,a case-based reasoning framework is proposed.Specifically,a Hamming distance and Euclidean distance combined method is designed to measure the similarity of case features which have both numeric and category properties.In addition,AHP(Analytic Hierarchy Process)and entropy weight method are integrated to provide features weight,where both user preferences and comprehensive impact of the index have been concerned.Grey relation analysis is used to obtain the similarity of a new problem and alternative cases.Finally,a platform is also developed on Visual Studio 2015,and a case study is demonstrated to verify the practicality and efficiency of the proposed method.This method can obtain cutting parameters which is suitable without iterative calculation.Compared with the traditional PSO(Particle swarm optimization algorithm)and GA(Genetic algorithm),it can obtain faster response speed.This method can provide ideas for selecting processing parameters in industrial production.While guaranteeing the characteristic information is similar,this approach can select processing parameters which is the most appropriate for the production process and a lot of time can be saved.

重组人源化Ⅲ型胶原蛋白对皮肤功能性相关基因表达的影响

重组人源化Ⅲ型胶原蛋白(RHCⅢ)由人胶原原始基因序列经过优化重组表达所得,与人体天然胶原氨基酸序列高度一致。为探究重组人源化Ⅲ型胶原蛋白应用在化妆品中,对减缓皮肤皱纹的功效作用,通过测试其作用于人皮肤成纤维细胞和角质形成细胞,在皮肤功能性基因层面验证其抗皱功效。结果表明,5 mg/mL RHCⅢ作用于人皮肤成纤维细胞可显著促进胶原合成相关基因CollagenⅠ,CollagenⅢ和Smad3的表达;同时,在UVA刺激条件下可显著抑制胶原降解相关基因MMP-1,MMP-3,c-jun和c-fos的表达。作用于角质形成细胞可显著促进皮肤屏障修复和保湿相关基因LOR,TGM1,IVL,OCLN1,DSG1,FLG,Caspase14和K1的表达。综上所述,样品重组人源化Ⅲ型胶原蛋白在5 mg/mL的给药质量浓度下具有抗皱功效。

Implementing an Optimal Energy Management System for a Set of Microgrids Using the Harmony Search Algorithm

A microgrid(MG)refers to a set of loads,generation resources and energy storage systems acting as a controllable load or a generator to supply power and heating to a local area.The MG-generated power management is a central topic for MG design and operation.The existence of dispersed generation(DG)resources has faced MG management with new issues.Depending on the level of exchanges between an MG and the main grid,the MG operation states can be divided into independent or grid-connected ones.Energy management in MGs aims to supply power at the lowest cost for optimal load response.This study examines MG energy management in two operational modes of islanded and grid-connected,and proposes a structure with two control layers(primary and secondary)for energy management.At the principal level of control,the energy management system is determined individually for all MG by taking into consideration the probability constraints and RES uncertainty by the Weibull the probability density function(PDF),generation resources’power as well as the generation surplus and deficit of each MG.Then,the information of the power surplus and deficit of each MG must be sent to the central energy management system.To confirm the proposed structure,a case system with two MGs and a condensive load is simulated by using a multi-time harmony search algorithm.Several scenarios are applied to evaluate the performance of this algorithm.The findings clearly show the effectiveness of the proposed system in the energy management of several MGs,leading to the optimal performance of the resources per MG.Moreover,the proposed control scheme properly controls the MG and grid’s performance in their interactions and offers a high level of robustness,stable behavior under different conditions and high quality of power supply.

Switchable shape memory polymer bio-inspired adhesive and its application for unmanned aerial vehicle landing

Controlled and switchable adhesion is commonly observed in biological systems.In recent years,many scholars have focused on making switchable bio-inspired adhesives.However,making a bio-inspired adhesive with high adhesion performance and excellent dynamic switching properties is still a challenge.A Shape Memory Polymer Bio-inspired Adhesive(SMPBA)was successfully developed,well realizing high adhesion(about 337 kPa),relatively low preload(about90 kPa),high adhesion-to-preload ratio(about 3.74),high switching ratio(about 6.74),and easy detachment,which are attributed to the controlled modulus and contact area by regulating temperature and the Shape Memory Effect(SME).Furthermore,SMPBA exhibits adhesion strength of80–337 kPa on various surfaces(silicon,iron,and aluminum)with different roughness(Ra=0.021–10.280)because of the conformal contact,reflecting outstanding surface adaptability.The finite element analysis verifies the bending ability under different temperatures,while the adhesion model analyzes the influence of preload on contact area and adhesion.Furthermore,an Unmanned Aerial Vehicle(UAV)landing device with SMPBA was designed and manufactured to achieve UAV landing on and detaching from various surfaces.This study provides a novel switchable bio-inspired adhesive and UAV landing method.

新西兰国家公园步道建设及启示

步道作为户外游憩的载体,是一种满足公众自然体验、游憩休闲和自然教育需求的带状休闲空间,与国家公园建设相辅相成。新西兰拥有成熟而完善的国家公园步道系统,在其100多年的发展过程中形成了先进的运行机制和管理理念。文中从功能、类型、特色和机制等方面梳理新西兰国家公园步道建设现状和发展理念,从规划设计、生态保护、健全法律和公众参与4个方面提出对我国国家公园步道体系建设的启示。依据路程用时、难易程度、建设标准、适宜人群和装备要求等的不同,新西兰将步道分为便捷的短途步道、短途步道、步行道、超级步道、徒步步道和线路步道6种类型。在兼顾生态保护的基础上,新西兰国家公园步道串联起不同类型的自然和人文景观资源,激活了特色历史和文化遗产资源,提高了游客游憩体验的满足感并提供自然教育的场所,具有多重功能。同时,通过建设与自然景观紧密结合的生态徒步小道、设施完善且形式多样的宿营地、形式简单且内容丰富的标识解说系统,新西兰建成了独具特色的国家公园步道系统。

Recent Advances in Organic Room-Temperature Phosphorescence of Heteroatom(B/S/P)-Containing Chromophores

Purely organic room-temperature phosphors,which have received extensive attention as emerging stateof-the-art luminescent materials in various fields,have a longer lifetime than fluorophores.The energy gap law and El-Sayed’s rule provide clear design principles for the development of organic room-temperature phosphorescence.Therefore,the incorporation of heteroatoms(such as sulfur and phosphorus)usually promotes the intersystem crossing rate and increases the 3(π,π*)configuration to realize long lifetimes.Furthermore,boron-containing phosphors not only display excellent phosphorescence properties but also expand El-Sayed’s rule without(n,π*)transitions.This review summarizes recent work on organic phosphorescence of heterocycles with boron,sulfur,and phosphorus heteroatoms and highlights the significance of the guidelines for constructing efficient phosphorescence molecules.This work is instrumental in further diversifying the pool of phosphorescent molecules and developing new and effective design strategies.

Hierarchical structures,surface morphology and mechanical elasticity of lamellar crystals dominated by halogen effects

To understand the deformation mechanism of molecular crystals under mechanical forces will accelerate the molecular design and preparation of deformable crystals.Herein,the relationship between structural halogenation and molecular-level stacking,micro/nanoscale surface morphology,and macroscopic mechanical properties are investigated.Elastic crystals of halo-pyrimidinyl carbazoles(CzM-Cl,CzM-Br and CzM-I)with lamellar structure and brittle crystal(CzM-F)were quantitatively analyzed by crystal energy framework(CEF)providing the inter/intralayer interaction energy(Inter/Intra-IE).It is revealed that the elastic crystals bend under external force as a result from stronger Intra-IE to prevent cleavage and weaker Inter-IE for the short-range movement of molecules on the slip plane.This research will provide an insight for the molecular design of flexible crystals and facilitate the development of next-generation smart crystal materials.

Power electronic transformer with adaptive PLL technique for voltage-disturbance ride through

The power electronic transformer(PET) has recently emerged as a type of power converter. It features the basic functions of power conversion and isolation as well as additional functions related to power quality control. A novel PET for a distribution grid called a flexible power distribution unit is proposed in this paper, and the energy exchange mechanism between the network and the load is revealed. A 30 kW 600 VAC/220 VAC/110 VDC medium-frequency isolated prototype is developed and demonstrated. This paper also presents key control strategies of the PET for electrical distribution grid applications,especially under grid voltage disturbance conditions.Moreover, stability issues related to the grid-connected three-phase PET are discussed and verified with an impedance-based analysis. The PET prototype is tested, and it passes the voltage-disturbance ride-through function. The experimental results verify the power quality control abilities of the PET.

Dual confinement of polysulfides in boron-doped porous carbon sphere/graphene hybrid for advanced Li-S batteries

A hybrid structure consisting of boron-doped porous carbon spheres and graphene （BPCS-G） has been designed and synthesized toward solving the polysulfide- shuttle problem, which is the most critical issue of current Li-S batteries. The proposed hybrid structure showing high surface area （870 m^2.g^-1） and high B-dopant content （6.51 wt.%） simultaneously offers both physical confinement and chemical absorption of polysulfides. On one hand, the abundant-pore structure ensures high sulfur loading, facilitates fast charge transfer, and restrains polysulfide migration during cycling. On the other hand, our density functional theory calculations demonstrate that the B dopant is capable of chemically binding polysulfides. As a consequence of such dual polysulfide confinement, the BPCS-G/S cathode prepared with 70 wt.% sulfur loading presents a high reversible capacity of 1,174 mAh.g^-1 at 0.02 C, a high rate capacity of 396 mAh·g^-1 at 5 G and good cyclability over 500 cycles with only 0.05% capacity decay per cycle. The present work provides an efficient and cost-effective platform for the scalable synthesis of high-performance carbon-based materials for advanced Li-S batteries.

Photosensitive damage of lysozyme caused by pazufloxacin and the protective effect of ferulic acid

Laser flash photolysis and sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE) experiments were carried out to study the photosensitive damage induced by pazufloxacin(PAX) and the protection of lysozyme(Lyso) by ferulic acid(FCA), an active antioxidant. Transient absorption spectra revealed electron transfer from Lyso and FCA to 3PAX*, with respective bimolecular reaction rate constants of 6.3×107 and 1.4×1010 dm3/(mol s). A pulse radiolysis study was also performed to investigate the formation of Lyso radical cations. Results showed that FCA effectively inhibited the cross-linking of protein induced by fluoroquinolones. Finally, a mechanism of the protective effect of FCA on Lyso was proposed.

Electric Vehicle Charging Simulation Framework Considering Traffic,User,and Power Grid

The traffic and user have significant impacts on the electric vehicle(EV)charging load but are not considered in the existing research.We propose a novel integrated simulation framework considering the traffic,the user,and power grid as well as the EV traveling,parking and charging based on cellular automaton(CA).The traffic is modeled by the traffic module of the proposed framework based on CA,while the power grid and user are modeled in the EV charging module.The traffic flow,user’s charging preference,user’s charging satisfaction,and the total supply capability(TSC)in the surveyed region are considered in the proposed framework.Two cases are carried out to show the interactions between the user and power grid.It is shown that the proposed framework can accurately simulate the interactions among traffic situation,user's behavior and TSC,which are significantly lacking in the existing research.The proposed framework is scalable in considering additional interrelated elements.

Regioisomerism effect(RIE) on optimizing ultralong organic phosphorescence lifetimes

Organic phosphorescence materials demonstrate potential optoelectronic applications due to their remarkably ultralong organic phosphorescence(UOP)lifetime and abundant optical characteristics prior to the fluorescence materials.For a better insight into the intrinsic relationship among regioisomeric molecules,crystalline interactions,and phosphorescence properties,three crystalline dicarbazol-9-yl pyrazine-based regioisomers with para-,meta-and ortho-convergent substitutions(p-DCzP,m-DCzP,and o-DCzP)were designed and presented gradually increased UOP lifetimes prolonging from 63.14,127.93 to 350.46 ms,respectively,due to the regioisomerism effect(RIE)which would be an effective strategy for better understanding of structure-property of UOP materials.

A Review on Distortion and Residual Stress in Additive Manufacturing

Additive manufacturing(AM)has gained extensive attention and tremendous research due to its advantages of fabricating complex-shaped parts without the need of casting mold.However,distortion is a known issue for many AM technologies,which decreases the precision of as-built parts.Like fusion welding,the local high-energy input generates residual stresses,which can adversely affect the fatigue performance of AM parts.To the best of the authors’knowledge,a comprehensive review does not exist regarding the distortion and residual stresses dedicated for AM,despite some work has explored the interrelationship between the two.The present review is aimed to fill in the identified knowledge gap,by first describing the evolution of distortion and residual stresses for a range of AM processes,and second assessing their influencing factors.This allows us to elucidate their formation mechanisms from both the micro-and macro-scales.Moreover,approaches which have been successfully adopted to mitigate both the distortion and residual stresses are reviewed.It is anticipated that this review paper opens many opportunities to increase the success rate of AM parts by improving the dimension precision and fatigue life.

考虑内禀材料长度变化的广义Aifantis应变梯度塑性模型

内禀材料长度是应变梯度塑性理论中最重要的参数,被用于成功地解释了微尺度下金属材料的尺寸效应.内禀材料长度在应变梯度框架中通常扮演着平衡量纲的角色,并且其取值依赖于模型.目前,内禀材料长度物理意义、与材料微观结构的关联以及随变形的演化尚未完全明确.本研究对Aifantis应变梯度塑性模型进行了修正,在其中引入了一个最新提出的幂律形式的内禀材料长度演化关系.在此基础上进一步考虑晶粒尺寸效应,基于Hall-Petch关系对Aifantis应变梯度塑性模型进行了扩展,使用上述修正的模型对细丝扭转的实验结果进行了模拟,研究结果表明,内禀材料长度同时取决于试样尺寸和晶粒尺寸,这些相关性主要由位错间距决定,并可以通过应变硬化指数很好地描述.此外,原始Aifantis模型和修正的Aifantis模型中的内禀材料长度的取值均比Fleck-Hutchinson模型的取值更大.

Green-synthesized,low-cost tetracyanodiazafluorene(TCAF) as electron injection material for organic light-emitting diodes

Two electron-deficient azaacenes including di-and tetra-cyanodiazafluorene(DCAF and TCAF)with the advantages of deep lowest unoccupied molecular orbital(LUMO),green-synthesis,low-cost,simply purification method,excellent yields have been obtained,characterized and used as electron injection materials(EIMs)in three groups of electroluminescence devices.Device B with TCAF as EIM exhibited the best performance including turn-on voltage of 5.0 V,stronger maximum luminance intensity of 31,549 cd/m2,higher luminance efficiency of 62.34 cd/A and larger power efficiency of 21.74 lm/W which are 0.53,6.7,9.3 and 15.3 times than that of device A with DCAF as EIMs,respectively.The enhanced interfacial electron injection ability of TCAF than that of DCAF is supported by its better electron mobility in electron-only device,deeper LUMO(-4.52 eV),and stronger electronic affinity.Best external quantum efficiency of 16.56%was achieved with optimized thicknesses of TCAF as EIM and TPBi as electron transporting layer.As a new comer of acceptor family,TCAF would push forward organic electronics with more fascinating and significant applications.