Pitch deviation at rack joints(PDRJ) is a common error in rack railways. It directly affects the contact characteristics between the rack and gear and leads to accelerated surface wear. This threatens the stability an...Pitch deviation at rack joints(PDRJ) is a common error in rack railways. It directly affects the contact characteristics between the rack and gear and leads to accelerated surface wear. This threatens the stability and service life of the rack system, and the theoretical understanding of this issue remains limited. To address this gap, this study develops an improved tooth wear model that simultaneously accounts for the instantaneous variations in meshing stiffness and dynamic transmission error(DTE) induced by PDRJ, as well as the real-time correlation between gear-rack contact position and meshing excitation. Subsequently, the rack tooth load and wear characteristics are evaluated through the rack vehicle-track coupled dynamics and gear-rack contact model. The model's reliability is verified through field measurements. Moreover, the influence of varying PDRJ levels on load sharing factors, surface wear depth, and rack displacement is investigated. The results show that PDRJ disrupts the theoretical gear-rack meshing process, resulting in non-uniform load distribution and accelerated wear, particularly in the addendum and dedendum regions of the rack teeth. This study provides valuable insights into the rack surface wear mechanism under PDRJ.展开更多
The dynamic characteristics of the track system can directly affect its service performance and failure process.To explore the load characteristics and dynamic response of the track system under the dynamic loads from...The dynamic characteristics of the track system can directly affect its service performance and failure process.To explore the load characteristics and dynamic response of the track system under the dynamic loads from the rack vehicle in traction conditions,a systematic test of the track subsystem was carried out on a large-slope test line.In the test,the bending stress of the rack teeth,the wheel-rail forces,and the acceleration of crucial components in the track system were measured.Subsequently,a detailed analysis was conducted on the tested signals of the rack railway track system in the time domain and the time-frequency domains.The test results indicate that the traction force significantly affects the rack tooth bending stress and the wheel-rail forces.The vibrations of the track system under the traction conditions are mainly caused by the impacts generated from the gear-rack engagement,which are then transferred to the sleepers,the rails,and the ballast beds.Furthermore,both the maximum stress on the racks and the wheel-rail forces measured on the rails remain below their allowable values.This experimental study evaluates the load characteristics and reveals the vibration characteristics of the rack railway track system under the vehicle’s ultimate load,which is very important for the load-strengthening design of the key components such as racks and the vibration and noise reduction of the track system.展开更多
活化的蛋白激酶C受体1(receptor for activated C kinase 1,RACK1)是一种细胞内重要的支架蛋白,与G蛋白β亚基具有显著的同源性,最初被发现能够介导蛋白激酶C的亚细胞定位和活性,而被称为蛋白激酶C的受体。在过去的30年中,RACK1介导的...活化的蛋白激酶C受体1(receptor for activated C kinase 1,RACK1)是一种细胞内重要的支架蛋白,与G蛋白β亚基具有显著的同源性,最初被发现能够介导蛋白激酶C的亚细胞定位和活性,而被称为蛋白激酶C的受体。在过去的30年中,RACK1介导的信号转导通路以及相关的功能,尤其是在肿瘤进程中的作用,得到越来越多的认可及重视。本文拟结合最近的研究进展,概述RACK1在常见肿瘤中的促肿瘤或抗肿瘤作用及其潜在机制。展开更多
Background With the increasing prominence of hand and finger motion tracking in virtual reality(VR)applications and rehabilitation studies,data gloves have emerged as a prevalent solution.In this study,we developed an...Background With the increasing prominence of hand and finger motion tracking in virtual reality(VR)applications and rehabilitation studies,data gloves have emerged as a prevalent solution.In this study,we developed an innovative,lightweight,and detachable data glove tailored for finger motion tracking in VR environments.Methods The glove design incorporates a potentiometer coupled with a flexible rack and pinion gear system,facilitating precise and natural hand gestures for interaction with VR applications.Initially,we calibrated the potentiometer to align with the actual finger bending angle,and verified the accuracy of angle measurements recorded by the data glove.To verify the precision and reliability of our data glove,we conducted repeatability testing for flexion(grip test)and extension(flat test),with 250 measurements each,across five users.We employed the Gage Repeatability and Reproducibility to analyze and interpret the repeatable data.Furthermore,we integrated the gloves into a SteamVR home environment using the OpenGlove auto-calibration tool.Conclusions The repeatability analysis revealed an aggregate error of 1.45 degrees in both the gripped and flat hand positions.This outcome was notably favorable when compared with the findings from assessments of nine alternative data gloves that employed similar protocols.In these experiments,users navigated and engaged with virtual objects,underlining the glove's exact tracking of finger motion.Furthermore,the proposed data glove exhibited a low response time of 17-34 ms and back-drive force of only 0.19 N.Additionally,according to a comfort evaluation using the Comfort Rating Scales,the proposed glove system is wearable,placing it at the WL1 level.展开更多
目的:研究O-GlcNAcylation调节蛋白激酶C受体1(receptor for activated C kinase 1,Rack1)的稳定性在SHH型髓母细胞瘤(SHH type medulloblastoma,SHH-MB)形成中的功能作用。方法:选取中国人民解放军西部战区总医院临床肿瘤标本库中分子...目的:研究O-GlcNAcylation调节蛋白激酶C受体1(receptor for activated C kinase 1,Rack1)的稳定性在SHH型髓母细胞瘤(SHH type medulloblastoma,SHH-MB)形成中的功能作用。方法:选取中国人民解放军西部战区总医院临床肿瘤标本库中分子分型所确定的SHH-MB肿瘤及癌旁组织,分析样本中Rack1和O-GlcNAcylation(O-Glc NAc)的表达水平差异。对于人源髓母细胞瘤细胞系Daoy使用糖基化转移酶(OGT)抑制剂(OSMI-1)和去糖基化转移酶(OGA)抑制剂(TM-G)进行处理,通过Cell Counting Kit-8(CCK-8)法和免疫荧光染色检测肿瘤细胞增殖能力。采用O-Glc NAc酶标记系统、免疫共沉淀(Co-IP)和Western blot法判断Rack1有无发生O-Glc NAc,而后通过环己酰亚胺(CHX)实验和泛素化修饰实验证实O-GlcNAcylation对Rack1蛋白水平的影响。构建敲低Rack1的髓母细胞瘤模型,通过Cell Counting Kit-8(CCK-8)法、免疫荧光染色和划痕实验检测肿瘤细胞增殖能力。同时通过在免疫缺陷型小鼠进行异种原位肿瘤移植进行验证,在所得组织样本中(sh-NC和shRack1)使用Western blot检测下游SHH信号通路变化。结果:Rack1和O-GlcNAcylation在SHH-MB中表达水平显著增高,且Rack1表达水平和患者生存率呈负相关关系。对Daoy细胞系使用OSMI-1、TM-G处理后,发现O-Glc NAc能明显促进Daoy细胞增殖,而抑制细胞O-GlcNAc则抑制细胞增殖。分子实验证实Rack1蛋白O-GlcNAcylation可以调节其蛋白稳定性,进而促进肿瘤细胞增殖。在Daoy细胞系敲低Rack1表达,其细胞增殖能力明显低于对照组;在动物水平方面,相较于对照组,Rack1蛋白敲低的肿瘤组织增殖受到显著抑制。并且Rack1可通过调节SHH信号通路参与SHH-MB形成。结论:O-GlcNAcylation可通过调节Rack1蛋白的稳定性进而参与SHH-MB形成。展开更多
This paper investigates the use of explainable artificial intelligence(XAI)and trustworthy artificial intelligence(TAI)methods for condition monitoring on a laser cutting machine.The focus is on the analysis of the ra...This paper investigates the use of explainable artificial intelligence(XAI)and trustworthy artificial intelligence(TAI)methods for condition monitoring on a laser cutting machine.The focus is on the analysis of the rack and pinion contact with wear being predicted by four differently derived adaptive-network-based fuzzy inference system(s)(ANFIS)models.Using both model-agnostic and model-specific parameters integrated in a weighted evaluation framework,the models are evaluated with respect to the effectiveness of explanations.This framework is based on the observation of the outputs of the individual layers of ANFIS,also focusing on aspects of two multivalued logics,namely fuzzy logic and support logic.The results show that the introduced weighted evaluation framework makes it possible to quantify the explainability of the individual models in terms of XAI and TAI.Finally,a preselection of a model for predicting the wear of the rack and pinion contact can be made.展开更多
LOKIBASE is a non-linear isolator/dissipator device to protect pallet racking systems against the earthquake.LOKIBASE consists of the following main components:(1)two slider devices on which a rubber membrane is set u...LOKIBASE is a non-linear isolator/dissipator device to protect pallet racking systems against the earthquake.LOKIBASE consists of the following main components:(1)two slider devices on which a rubber membrane is set up(LOKI devices).LOKI devices are linear displacement dependent ones;(2)a cylindrical beam damper(“CANDLE”device).The“CANDLE”device is a non-linear displacement dependent one;(3)two anti-lifting devices(“UP-LIFT”devices);(4)a fuse plug(see www.lokibasedevice.com).The main work which is the purpose of the paper,is the optimization of the behavior of an isolator/dissipator device to mitigate the seismic action on special structures,where the stiffness values are very different in the main cross-aisle and down-aisle directions.Under seismic action,in these structures it is very important to reduce the value of the forces at the Limit state for the safeguard of human life(SLV)in the down-aisle direction as much as possible and simultaneously to use the highest damping value allowed by the building rules to reduce the LOKIBASE displacement at the Limit state for collapse prevention(SLC)in the cross-aisle direction.The goal was achieved through a cylindrical device made of stainless steel(AISI304)with an optimized shape,under large displacement during seismic action.展开更多
Covalent organic frameworks(COFs)are two-(2D)or threedimensional(3D)crystalline,porous networks generated by reversible polymerization of organic building blocks[1,2].The structures and functionalities of COFs are pre...Covalent organic frameworks(COFs)are two-(2D)or threedimensional(3D)crystalline,porous networks generated by reversible polymerization of organic building blocks[1,2].The structures and functionalities of COFs are precisely controlled via appropriately selected organic building blocks.This design imparts unique properties to COFs,including exceptional structural stability,tunable pore structure,and surface chemical activity,making them promising for gas separation,catalysis,optoelectronics,and sensing applications.Since Yaghi et al.'s seminal report on COFs in 2005[2],these frameworks have swiftly emerged as a hotspot in the field of materials.Originally,the focus was on fabricating rigid frameworks with static structures and optoelectronic properties.However,the inherently static nature of these frameworks hinders their responsiveness to external stimuli,potentially constraining their functionality in specific applications.Hence,an increasing number of researchers are now directing their attention toward the development of dynamic COFs capable of modifying their structures in response to external stimuli[3].Specifically,dynamic 2D COFs exhibiting enhanced structural responsiveness are of particular interest due to their capability to integrate switchable geometries and porosities with semiconductor building blocks,as well as electron conjugation across COF layers and π-stacked columns,which may enable stimuli-responsive electronic and spin properties[4].展开更多
基金supported by the National Natural Science Foundation of China (Grant No.52388102)the Sichuan Science and Technology Program (Grant No.2024NSFTD0011)the Fundamental Research Funds for the State Key Laboratory of Rail Transit Vehicle System of Southwest Jiaotong University (Grant No.2023TPL-T11)。
文摘Pitch deviation at rack joints(PDRJ) is a common error in rack railways. It directly affects the contact characteristics between the rack and gear and leads to accelerated surface wear. This threatens the stability and service life of the rack system, and the theoretical understanding of this issue remains limited. To address this gap, this study develops an improved tooth wear model that simultaneously accounts for the instantaneous variations in meshing stiffness and dynamic transmission error(DTE) induced by PDRJ, as well as the real-time correlation between gear-rack contact position and meshing excitation. Subsequently, the rack tooth load and wear characteristics are evaluated through the rack vehicle-track coupled dynamics and gear-rack contact model. The model's reliability is verified through field measurements. Moreover, the influence of varying PDRJ levels on load sharing factors, surface wear depth, and rack displacement is investigated. The results show that PDRJ disrupts the theoretical gear-rack meshing process, resulting in non-uniform load distribution and accelerated wear, particularly in the addendum and dedendum regions of the rack teeth. This study provides valuable insights into the rack surface wear mechanism under PDRJ.
基金supported by the National Natural Science Foundation of China(No.52388102)the Sichuan Science and Technology Program(No.2024NSFTD0011)the Fundamental Research Funds for the State Key Laboratory of Rail Transit Vehicle System of Southwest Jiaotong University(No.2023TPL-T11).
文摘The dynamic characteristics of the track system can directly affect its service performance and failure process.To explore the load characteristics and dynamic response of the track system under the dynamic loads from the rack vehicle in traction conditions,a systematic test of the track subsystem was carried out on a large-slope test line.In the test,the bending stress of the rack teeth,the wheel-rail forces,and the acceleration of crucial components in the track system were measured.Subsequently,a detailed analysis was conducted on the tested signals of the rack railway track system in the time domain and the time-frequency domains.The test results indicate that the traction force significantly affects the rack tooth bending stress and the wheel-rail forces.The vibrations of the track system under the traction conditions are mainly caused by the impacts generated from the gear-rack engagement,which are then transferred to the sleepers,the rails,and the ballast beds.Furthermore,both the maximum stress on the racks and the wheel-rail forces measured on the rails remain below their allowable values.This experimental study evaluates the load characteristics and reveals the vibration characteristics of the rack railway track system under the vehicle’s ultimate load,which is very important for the load-strengthening design of the key components such as racks and the vibration and noise reduction of the track system.
文摘活化的蛋白激酶C受体1(receptor for activated C kinase 1,RACK1)是一种细胞内重要的支架蛋白,与G蛋白β亚基具有显著的同源性,最初被发现能够介导蛋白激酶C的亚细胞定位和活性,而被称为蛋白激酶C的受体。在过去的30年中,RACK1介导的信号转导通路以及相关的功能,尤其是在肿瘤进程中的作用,得到越来越多的认可及重视。本文拟结合最近的研究进展,概述RACK1在常见肿瘤中的促肿瘤或抗肿瘤作用及其潜在机制。
基金Supported by the Sirindhorn International Institute of Technology,Thammasat University,EFS-G(Excellent foreign Student-Graduate)research fund.
文摘Background With the increasing prominence of hand and finger motion tracking in virtual reality(VR)applications and rehabilitation studies,data gloves have emerged as a prevalent solution.In this study,we developed an innovative,lightweight,and detachable data glove tailored for finger motion tracking in VR environments.Methods The glove design incorporates a potentiometer coupled with a flexible rack and pinion gear system,facilitating precise and natural hand gestures for interaction with VR applications.Initially,we calibrated the potentiometer to align with the actual finger bending angle,and verified the accuracy of angle measurements recorded by the data glove.To verify the precision and reliability of our data glove,we conducted repeatability testing for flexion(grip test)and extension(flat test),with 250 measurements each,across five users.We employed the Gage Repeatability and Reproducibility to analyze and interpret the repeatable data.Furthermore,we integrated the gloves into a SteamVR home environment using the OpenGlove auto-calibration tool.Conclusions The repeatability analysis revealed an aggregate error of 1.45 degrees in both the gripped and flat hand positions.This outcome was notably favorable when compared with the findings from assessments of nine alternative data gloves that employed similar protocols.In these experiments,users navigated and engaged with virtual objects,underlining the glove's exact tracking of finger motion.Furthermore,the proposed data glove exhibited a low response time of 17-34 ms and back-drive force of only 0.19 N.Additionally,according to a comfort evaluation using the Comfort Rating Scales,the proposed glove system is wearable,placing it at the WL1 level.
基金This project(ProKInect N°02P20A090)was funded by the German Federal Ministry of Education and Research(BMBF)within the“The Future of Value Creation-Research on Production,Services and Work”program and managed by the Project Management Agency Karlsruhe(PTKA).The support is greatly acknowledged.
文摘This paper investigates the use of explainable artificial intelligence(XAI)and trustworthy artificial intelligence(TAI)methods for condition monitoring on a laser cutting machine.The focus is on the analysis of the rack and pinion contact with wear being predicted by four differently derived adaptive-network-based fuzzy inference system(s)(ANFIS)models.Using both model-agnostic and model-specific parameters integrated in a weighted evaluation framework,the models are evaluated with respect to the effectiveness of explanations.This framework is based on the observation of the outputs of the individual layers of ANFIS,also focusing on aspects of two multivalued logics,namely fuzzy logic and support logic.The results show that the introduced weighted evaluation framework makes it possible to quantify the explainability of the individual models in terms of XAI and TAI.Finally,a preselection of a model for predicting the wear of the rack and pinion contact can be made.
文摘LOKIBASE is a non-linear isolator/dissipator device to protect pallet racking systems against the earthquake.LOKIBASE consists of the following main components:(1)two slider devices on which a rubber membrane is set up(LOKI devices).LOKI devices are linear displacement dependent ones;(2)a cylindrical beam damper(“CANDLE”device).The“CANDLE”device is a non-linear displacement dependent one;(3)two anti-lifting devices(“UP-LIFT”devices);(4)a fuse plug(see www.lokibasedevice.com).The main work which is the purpose of the paper,is the optimization of the behavior of an isolator/dissipator device to mitigate the seismic action on special structures,where the stiffness values are very different in the main cross-aisle and down-aisle directions.Under seismic action,in these structures it is very important to reduce the value of the forces at the Limit state for the safeguard of human life(SLV)in the down-aisle direction as much as possible and simultaneously to use the highest damping value allowed by the building rules to reduce the LOKIBASE displacement at the Limit state for collapse prevention(SLC)in the cross-aisle direction.The goal was achieved through a cylindrical device made of stainless steel(AISI304)with an optimized shape,under large displacement during seismic action.
基金supported by the National Natural Science Foundation of China(Nos.51902121 and 22372067)。
文摘Covalent organic frameworks(COFs)are two-(2D)or threedimensional(3D)crystalline,porous networks generated by reversible polymerization of organic building blocks[1,2].The structures and functionalities of COFs are precisely controlled via appropriately selected organic building blocks.This design imparts unique properties to COFs,including exceptional structural stability,tunable pore structure,and surface chemical activity,making them promising for gas separation,catalysis,optoelectronics,and sensing applications.Since Yaghi et al.'s seminal report on COFs in 2005[2],these frameworks have swiftly emerged as a hotspot in the field of materials.Originally,the focus was on fabricating rigid frameworks with static structures and optoelectronic properties.However,the inherently static nature of these frameworks hinders their responsiveness to external stimuli,potentially constraining their functionality in specific applications.Hence,an increasing number of researchers are now directing their attention toward the development of dynamic COFs capable of modifying their structures in response to external stimuli[3].Specifically,dynamic 2D COFs exhibiting enhanced structural responsiveness are of particular interest due to their capability to integrate switchable geometries and porosities with semiconductor building blocks,as well as electron conjugation across COF layers and π-stacked columns,which may enable stimuli-responsive electronic and spin properties[4].
