WEAR FAILURE MECHANISM AND MULTI-IMPACT PROPERTY OF AUTOMOTIVE ENGINE CHAIN

The multi-impact characteristics and failure mechanism of two kinds of automotive engine chain made in China are studied through engine assembly and road-drive tests. The worn surface morphologies of rubbing area between pin, bush and roller are also analyzed based on scanning electron microscope. The results show that the main wear mechanism of automotive engine chain is fatigue wear, and its failure mechanism is the forming, extending and flaking of cracks on top layer of pin and bush. In addition, the material, hot-treatment method and shaping technique for roller have a great influence upon the resistance to multi-impact. Ensuring sufficient strength and plasticity of roller, as well as adopting suitable shaping technique are the effective method to increase its resistance to multi-impact.

EXPERIMENTAL STUDY ON HIGH-SPEED CHARACTERISTICS OF AUTOMOTIVE ENGINE OIL-PUMP CHAIN

The high-speed multi-cycle impact and speed, load fluctuant characteristics of a kind of narrow-width automotive engine oil-pump chain 06BN-1 are studied through engine assembly and road-drive tests to satisfy the light-weight demand of engine. The worn surface morphologies of rubbing area between pin, bush and roller are also analyzed based on scanning electron microscope. The results show that the main wear mechanism of automotive engine oil-pump chain is fatigue wear, and it＇s failure mechanism is the forming, extending and flaking of cracks on top layer of pin and bush. Pin and bush both occurred cycle-soften phenomenon, and roller occurred cycle-harden. Fretting wear is one of the most important ＂fall to pieces＂ failure causes of automotive chain. Ensuring sufficient strength and plasticity of roller, as well as adopting suitable shaping technology are the effective methods to increase its resistance to multi-cycle impact.

Recent progress in side chain engineering of Y-series non-fullerene molecule and polymer acceptors

Organic solar cells(OSCs) have drawn considerable attention in the last decade due to the great potential of light weight,flexibility, and low-cost solution processing. Particularly, Y-series non-fullerene acceptors(NFAs) including small molecular acceptors(SMAs) and polymerized small molecular acceptors(PSMAs) have become research hot spots due to their excellent power conversion efficiency. Side chain engineering is crucial to adjust the solubility and crystallinity of NFAs, which will significantly affect the morphology of active layers and the efficiency of OSCs. However, the understanding of side chain engineering on NFAs is still limited and lacks a systematic review. This review aims to provide a brief summary of the recent developments in side chain engineering of NFAs, with a special focus on the design and application of Y-series SMAs and PSMAs for high-efficiency non-fullerene organic solar cells(NF-OSCs). In addition, the review also points out challenges and provides useful guidance regarding side chain regulation for Y-series NFAs.

Silane or Siloxane-Side-Chain Engineering of Photovoltaic Materials for Organic Solar Cells

With the tactful material design,skillful device engineering,and in-depth understanding of morphology optimization,organic solar cells (OSCs) have achieved considerable success.Therefore,OSCs have reached high power conversion efficiencies (PCEs) exceeding 19%.Especially,continuously emerging new materials have been considered as one of the key factors to improve the PCEs of OSCs.Among molecular design strategies,side-chain engineering is an easy and commonly-used means which can optimize the solubility,alter intermolecular stacking arrangement,fine-tune the open circuit voltage (VOC),thus ultimately improve the performance.As hybrid side chains,silane and siloxane side chains have considerable effects,not only in increasing the carrier mobility and tuning the energy level,but also in affecting the crystallinity and molecular orientation.In this review,the latest developments in photovoltaic materials based on silane and siloxane side chains are presented to illustrate the structure-property relationships.The review comprehensively includes silane-side based polymer/small molecule donors;siloxane-side based polymer/small molecule donors,and polymer/small molecule acceptors.Then the similarities and differences between these two side chains are demonstrated.Finally,the possible applications and future prospects of silane and siloxane side chains are presented.

生态工业工程在发展矿区循环经济中的应用

本文根据循环经济的理论内涵,分析了其生态经济的本质;引入和扩展可更新资源生态产业链概念进行矿区生态产业链设计,构架矿区城市生态产业链设计的理念与矿区城市循环经济的初步模式;在生态工业工程理念指导下,以徐州市为例,进行典型资源型(矿区)城市循环经济建设研究。

Supply Chain Engineering in China's Retailing Industry: A Case of Meiyijia

This paper addresses the supply chain engineering and its application in China’s retailing industry. Based on the approaches of systems engineering, we propose the concept of supply chain engineering, which applies the idea of supply chain management to the engineering practices through the advanced information and management technology, to integrate the supply chain system and optimize its operations. We then illustrate the application of the supply chain engineering in China’s retailing industry. In such practices, we developed the virtual retailing enterprise mode and the FROM-SCM system, and designed the sales assistant etc. Such theory and practices are successfully applied in Meiyijia, which has transformed Meiyijia from a traditional retailer to a modern service enterprise, and the profits are resulted from the service fees rather than the traditional surplus between buying and selling prices. Now Meiyijia has built an ecosystem with the retailer in the core, the headquarter as the service platform. The success of Meiyijia in recent years shows the effectiveness of the supply chain engineering.

Manipulating molecular aggregation and crystalline behavior of A-DA’D-A type acceptors by side chain engineering in organic solar cells

Alkyl chains engineering plays an important role in photovoltaic materials for organic solar cells.Herein,three A-DA’D-A(acceptor–donor–acceptor’–donor–acceptor)type acceptors named Y6,Y6-C4,and Y6-C5 with different branching position on the pyrrole motif are discussed and the relationship between molecular aggregation,crystalline,and device performance are systematically investigated.The distance between the branching position and the main backbone affects their optical absorption and energy levels.Y6-C4 and Y6-C5 with the branching position at the fourth and fifth carbon of the alkyl chain show blue-shifted absorption and increased electrochemical bandgaps,compared with Y6 with the branching position at the second carbon of the alkyl side chain.In addition,this distance influences the molecular aggregation and crystalline behavior of the donor/acceptor blends.Compared with Y6-C4,Y6-C5 possesses a stronger crystalline and aggregate ability in the blends with a lower non-radiative energy loss,which results in a higher open circuit voltage(Voc)of 0.88 V.Finally,Y6-C5-based binary device achieved a high power conversion efficiency up to 16.73%with afill factor(FF)of 0.78.These results demonstrate that the side chain engineering is an effective strategy for tuning the molecular aggregation and crystalline to improve photovoltaic performance of the A-DA’D-A type acceptors.

Asymmetric molecular engineering in recent nonfullerene acceptors for efficient organic solar cells

Nonfullerene acceptors(NFAs),which usually possess symmetric skeletons,have drawn great attention in recent years due to their pronounced advantages over the fullerene counterparts.Moreover,breaking the symmetry of NFAs could fine tune the molecular dipole,solubility,energy level,intermolecular interaction,molecular packing,crystallinity,etc.,and give rise to improved photovoltaic performance.Currently,there are three main strategies for the design of asymmetric NFAs.This review highlights the recent advances of high-performance asymmetric NFAs and briefly outlooks the materials exploration for the future.

Recent progress in design of conductive polymers to improve the thermoelectric performance

Organic semiconductors,especially polymer semiconductors,have attracted extensive attention as organic thermoelectric materials due to their capabilities for flexibility,low-cost fabrication,solution processability and low thermal conductivity.However,it is challenging to obtain high-performance organic thermoelectric materials because of the low intrinsic carrier concentration of organic semiconductors.The main method to control the carrier concentration of polymers is the chemical doping process by charge transfer between polymer and dopant.Therefore,the deep understanding of doping mechanisms from the point view of chemical structure has been highly desired to overcome the bottlenecks in polymeric thermoelectrics.In this contribution,we will briefly review the recently emerging progress for discovering the structure–property relationship of organic thermoelectric materials with high performance.Highlights include some achievements about doping strategies to effectively modulate the carrier concentration,the design rules of building blocks and side chains to enhance charge transport and improve the doping efficiency.Finally,we will give our viewpoints on the challenges and opportunities in the field of polymer thermoelectric materials.

18.55% Efficiency Polymer Solar Cells Based on a Small Molecule Acceptor with Alkylthienyl Outer Side Chains and a Low-Cost Polymer Donor PTQ10

The development of A-DA′D-A type small molecule acceptors(SMAs)has promoted the rapid progress of polymer solar cells(PSCs)in recent years.The outer side chains on the terminal thiophene ring and inner side chains on nitrogen atoms of the pyrrole ring of the DA′D fused ring play important roles in the photovoltaic performance of the SMAs.Here,we synthesized two new SMAs,2,2′-((2Z,2′Z)-((12,13-bis(2-ethylhexyl)-3,9-bis(4-(2-ethylhexyl)thiophen-2-yl)-12,13-dihydro-[1,2,5]thiadiazolo[3,4-e]thieno[2″,3″:4′,5′]thieno[2′,3′:4,5]pyrrolo[3,2-g]thieno[2′,3′:4,5]thieno[3,2-b]indole-2,10-diyl)bis(methaneylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile(T2EH)and 2,2′-((2Z,2′Z)-((12,13-bis(2-ethylhexyl)-3,9-bis(3-(2-ethylhexyl)phenyl)-12,13-dihydro-[1,2,5]thiadiazolo[3,4-e]thieno[2″,3″:4′,5′]thieno[2′,3′:4,5]pyrrolo[3,2-g]thieno[2′,3′:4,5]thieno[3,2-b]indole-2,10-diyl)bis(methaneylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene)(P2EH),with 2-ethylhexylβ-substituted thienyl or phenyl as the outer side chains,respectively,to improve the photovoltaic properties of the SMAs.Compared with P2EH,T2EH exhibits closerπ−πstacking,slightly red-shifted absorption,and higher electron mobility.Moreover,the active layer of T2EH blended with the low-cost polymer donor poly[(thiophene)-alt-(6,7-difluoro-2-(2-hexyldecyloxy)quinoxaline)](PTQ10)possesses higher mobilities,a longer lifetime,and less recombination of the charge carriers in comparison with that of the PTQ10:P2EH active layer.Eventually,the PTQ10:T2EH-based PSCs showed an outstanding power conversion efficiency(PCE)of 18.55%,while the PSC based on PTQ10:P2EH displayed a PCE of 17.50%.Importantly,18.55%is the highest PCE in the PTQ10-based binary PSCs so far.The results indicate that T2EH is one of the best SMAs for the PTQ10-based PSCs and is a promising SMA for the application of PSCs.

通过侧链工程提高A-D-A'-D-A型非稠环电子受体的光伏性能

非稠环电子受体(NFREA)具有合成简单和结构修饰灵活的特点,是制备高性能低成本有机太阳电池(OSCs)的理想材料.本工作以不同侧链修饰的二氟苯并三氮唑(ffBTz)作为弱缺电子核(A’),分别设计合成了三种A-D-A’-D-A型NFREA,即ffBTz-BO、ffBTz-EH和ffBTz-C4.其中,ffBTz-EH,由于其合适的侧链长度,在分子结晶度和分子堆积优势取向之间取得了平衡,从而获得了更高的电荷迁移率.并且得益于高效的电荷传输和最合适的相分离形貌,基于ffBTz-EH的OSC获得12.96%的最高能量转换效率,这也是A-D-A’-D-A型NFREA获得的最高效率之一.本研究表明,A’核心上的烷基侧链在调节分子结晶度、活性层形貌和进一步调控器件性能方面起着至关重要的作用,这为未来设计高效低成本的A-D-A’-D-A型非稠环电子受体提供了思路.

An IPC-based Prolog design pattern for integrating backward chaining inference into applications or embedded systems

Prolog is one of the most important candidates to build expert systems and AI-related programs and has potential applications in embedded systems. However, Prolog is not suitable to develop many kinds of components, such as data acquisition and task scheduling, which are also crucial. To make the best use of the advantages and bypass the disadvantages, it is attractive to integrate Prolog with programs developed by other languages. In this paper, an IPC-based method is used to integrate backward chaining inference implemented by Prolog into applications or embedded systems. A Prolog design pattern is derived from the method for reuse, whose principle and definition are provided in detail. Additionally, the design pattern is applied to a target system, which is free software, to verify its feasibility. The detailed implementation of the application is given to clarify the design pattern. The design pattern can be further applied to wide range applications and embedded systems and the method described in this paper can also be adopted for other logic programming languages.

Ternary solvent-processed efficient organic solar cells based on a new A-DA'D-A acceptor derivative employing the 3^(rd)-position branching side chains on pyrroles

Recent advances in non-fullerene acceptors(NFAs),typically Y6,have driven power conversion efficiency(PCE) of single-junction orga nic solar cells(OSCs) over 16%.Mea nwhile,it becomes essential to know how to adopt simple strategies to further improve device performance.In this work,a new A-DA'D-A acceptor derivative,Y19-N3 employing 3-ethylheptyl branched at the 3^(rd)-position instead of 2-ethylhexyl on the pyrroles of Y19 is reported.The selection of an appropriate solvent in casting device is implemented to maximize the photovoltaic performance.PBDB-T:Y19-N3-based OSCs treated with a ternary solvent of CF/CB(1:3,v/v) and 0.8% DIO exhibit the optimal PCE of 13.77% here,with the significantly improved V_(oc)(0.78 V) and FF(0.72) as well as the high J_(sc)(24.46 mA/cm^(2)).Further characterizations indicate that this ternary solvent-treated PBDB-T/Y19-N3 film exhibits the more appropriate morphological features with the highly efficient charge generation and collection as well as the more balanced electron and hole mobilities.This work combines molecular design and device engineering to improve the photovoltaic properties,which is important to the development of OSCs.

Low-Cost and High-Performance Polymer Solar Cells with Efficiency Insensitive to Active-Layer Thickness

The power conversion efficiency(PCE)of polymer solar cells(PSCs)has recently increased quickly,propelling PSCs closer to large-scale commercialization.However,several critical issues,such as the cost of materials and the sensitivity of the PCE to active-layer thickness,must be addressed before industrial application can be realized on a large scale.Here,we fabricated a high-performance ternary PSC based on a low-cost polymer donor PTQ10 and an A-DA’D-A-type small molecule acceptor(SMA)2,2'-((2Z,2'Z)-((12,13-bis(2-butyloctyl)-3,9-bis(4-(2-ethylhexyl)thiophen-2-yl)-12,13-dihydro-[1,2,5]thiadiazolo[3,4-e]thieno[2'',3'':4',5']thieno[2',3':4,5]pyrrolo[3,2-g]thieno[2',3':4,5]thieno[3,2-b]indole-2,10-diyl)bis(methaneylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile(m-TEH)with a newA-DA’D-A-type SMA 2,2'-((2Z,2'Z)-((12,13-bis(2-butyloctyl)-3,9-bis(3-(2-ethylhexyl)phenyl)-12,13-dihydro-[1,2,5]thiadiazolo[3,4-e]thieno[2'',3'':4',5']thieno[2',3':4,5]pyrrolo[3,2-g]thieno[2',3':4,5]thieno[3,2-b]indole-2,10-diyl)bis(methaneylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile(m-PEH)(with phenyl outer side chains)as the third component.Benefitting from the good compatibility and the unique alignment of the energy levels between PTQ10 and the two SMAs,the ternary system showed favorable phase separation and dominant face-on orientation,exhibiting suitable film morphology and enhanced charge transport.Therefore,the optimized ternary PSCs based on PTQ10∶m-TEH∶m-PEH(1.0∶0.9∶0.3,w/w/w)demonstrated an outstanding PCE of 19.34%,which is one of the highest PCEs reported for the single junction PSCs to date.More importantly,the ternary PSCs demonstrated superior tolerance to the active-layer thickness and showed a high PCE of 18.02% with a high fill factor(FF)of 76.56% for the devices with the active-layer thickness even reaching 300 nm.These results indicate that the ternary devices based on PTQ10∶m-TEH∶m-PEH are highly promising for future large-area fabrication and commercial application of PSCs.

19.3% Efficiency ternary organic solar cells enabled by the alkyl side-chain effect of guest non-fullerene acceptors

The effect of side-chain engineering of conjugated molecules on the morphology and device performance in binary organic solar cells has been widely investigated. However, this relationship has hardly been studied in the guest components of ternary organic solar cells. In this study, a family of non-fullerene guest acceptors, namely XY-3, XY-5 and XY-7, with hydrogen substituent,straight and branched alkyl chains on the bithiophene units, respectively, were designed and synthesized to understand their effects on aggregation properties and device performance. The straight and branched alkyl chains on the bithiophene units result in sightly blue-shifted absorption compared to the hydrogen substituent and the XY-7 demonstrates the most appropriate phase separation scale and the most balanced charge transport. Consequently, the OSCs based on D18:e C9:XY-7 achieve a high shortcircuit current density(JSC) and fill factor(FF), while maintaining the enhancement of the open-circuit voltage(VOC) achieving an efficiency of 19.32%, exceeding those of D18:e C9, D18:e C9:XY-3, D18:e C9:XY-5(PCE:18.28%, 19.04%, 18.75%, respectively). These results highlight that the side-chain engineering of Y series non-fullerene acceptors as the guest acceptors has great potential in optimizing morphology properties and promoting photovoltaic performance.

Subtle Effect of Alkyl Substitutedπ-Bridges on Dibenzo[a,c]phenazine Based Polymer Donors towards Enhanced Photovoltaic Performance

Selection of the strategically substituted alkyl chains has a significant effect to modulate the physical properties of conjugated polymers,electro-optical characteristics,and active layer morphology of the corresponding polymer solar cells(PSCs).Herein,we systematically synthesized three dibenzo[a,c]phenazine based D-π-A donor polymers named PBP-C0,PBP-C8,and PBP-C6 with different alkyl substitutions on thiopheneπ-bridges,without alkyl,2-ethylhexyl and n-hexyl groups,respectively.The absence of the alkyl chain(PBP-C0)on theπ-bridge caused poor solubility and unfavorable miscibility with the Y5 acceptor,leading to the lower photovoltaic performance.The bulky alkyl chain of 2-ethylhexyl on theπ-bridge group caused the twisting of PBP-C8 conjugated backbone,which limits the charge transport and also compromises the photovoltaic performance.In contrast,the PBP-C6-with flexible linear alkyl chains has almost planar curvature geometry resulting in the small uniform domain size and appropriate phase separation in the blend film morphology.These favorable properties enhanced the exciton generation to dissociation,charge carrier mobility,and also lowered the charge recombination.Among three polymers,PBP-C6-based devices exhibit the best PCE of 11.60%.From these results,thiopheneπ-bridge alkyl substitution demonstrated an important strategy to adjust energy level,absorption,and phase separation morphology to enhance the photovoltaic performance of the PSCs.