The effects of austempering temperature on microstructure and surface residual stress of carbidic austempered ductile iron （CADI） grinding balls were systematically investigated in this work. The microstructures we...The effects of austempering temperature on microstructure and surface residual stress of carbidic austempered ductile iron （CADI） grinding balls were systematically investigated in this work. The microstructures were oberserved by optical metallography and analyized by X-ray diffraction. The surface residual stress measured by the cutting method is mainly composed of thermal stress and phase transformation stress.The thermal stress in grinding balls was determined by ANSYS simulation technique, and the surface phase transformation stress was obtained by subtracting the simulated surface thermal stress from the measured surface residual stress. Results show that all microstructures consist of ausferrite, white-bright zones （mixture of martensite and austenite）, nodular graphite, and carbides. The distribution of ausferrite shows uniform. With the increase of austempering temperature, the volume fraction and carbon content of austenite increase, whereas the amount of white-bright zone decreases. In addition, the surface residual stress increases with the increase of austempering temperature. Only the tension exists at the austempering temperature of 200 ℃, and the pressure exists at the austempering temperature of 220-260 °C. The thermal stress changes from the tension on the inside with the radius of 0-35 mm to the pressure on the outside with the radius of 35-62.5 mm, and the stress balance state presents at the radius of 35 mm. It is also found that the transformation stress is related to the content of carbon-rich austenite, and will reduce by 5.03 MPa accompanied with 1vol.% increase of the austenite.The thermal compressive stress and the transformation tensile stress on the surface both decrease with the increase of the austempering temperature.展开更多
Electron-deficient viologens are widely used as ligands or structure-directing agents(SDAs)to synthesize crystalline X-ray induced photochromic materials.Here,a new rational strategy of anion-directed fold-ing a flexi...Electron-deficient viologens are widely used as ligands or structure-directing agents(SDAs)to synthesize crystalline X-ray induced photochromic materials.Here,a new rational strategy of anion-directed fold-ing a flexible cation(H_(2)imb)^(2+)((H_(2)imb)^(2+)=di-protonated 2,3-bis(imidazolin-2-yl)-2,3-dimethylbutane)has been developed.Electron-donating Cl−and(ZnCl4)2−are used to direct folding a flexible electron-deficient(H_(2)imb)^(2+)cation.Three complexes(H_(2)imb)(NO_(3))2(1),(H_(2)imb)Cl2·H_(2)O(2),and(H_(2)imb)ZnCl4(3)have been synthesized in which(H_(2)imb)^(2+)crystallize in an anti-conformation,88.8°-gauche,and 51.8°-gauche,respectively.In contrary to X-ray silent complex 1,X-ray induced photochromism has been achieved in both complex 2 and 3.An intermolecular charge-transfer mechanism has been elucidated and the anion directed folding of(H_(2)imb)^(2+)has been validated to be critical to yield colored long-lived charge-separated states.展开更多
Pyroptosis plays an important role in hemorrhagic stroke.Excessive endoplasmic reticulum stress can cause endoplasmic reticulum dysfunction and cellular pyroptosis by regulating the nucleotide-binding oligomerization ...Pyroptosis plays an important role in hemorrhagic stroke.Excessive endoplasmic reticulum stress can cause endoplasmic reticulum dysfunction and cellular pyroptosis by regulating the nucleotide-binding oligomerization domain and leucine-rich repeat pyrin domain-containing protein 3(NLRP3)pathway.However,the relationship between pyroptosis and endoplasmic reticulum stress after intraventricular hemorrhage is unclear.In this study,we established a mouse model of intraventricular hemorrhage and found pyroptosis and endoplasmic reticulum stress in brain tissue.Intraperitoneal injection of the selective GPR120 agonist TUG-891 inhibited endoplasmic reticulum stress,pyroptosis,and inflammation and protected neurons.The neuroprotective effect of TUG-891 appears related to inhibition of endoplasmic reticulum stress and pyroptosis activation.展开更多
It has been reported that Arabidopsis chloroplast accD transcripts undergo RNA editing and that loss of accD-C794 RNA editing does not affect plant growth under normal conditions.To date,the exact biological role of a...It has been reported that Arabidopsis chloroplast accD transcripts undergo RNA editing and that loss of accD-C794 RNA editing does not affect plant growth under normal conditions.To date,the exact biological role of accD-C794 editing has remained elusive.Here,we reveal an unexpected role for accD-C794 editing in response to heat stress.Loss of accD-C794 editing results in a yellow and dwarf phenotype with decreased chloroplast gene expression under heat stress,and artificial improvement of C794-edited accD gene expression enhances heat tolerance in Arabidopsis.These data suggest that accD-C794 editing confers heat tolerance in planta.We also found that treatment with the product of acetyl coenzyme A carboxylase(ACCase)could allay mutant phenotypic characteristics and showed that a mutation in the CAC3 gene for the a-subunit of ACCase was associated with dwarfism under heat stress.These observations indicate that defective accD-C794 editing may be intrinsic to reduced ACCase activity,thereby contributing to heat sensitivity.ACCase catalyzes the committed step of de novo fatty acid(FA)biosynthesis.FA content analysis revealed that unsaturated oleic(C18:1)and linoleic acids(C18:2)were low in the accD-C794 editing-defective mutant but high in the C794-edited accD-overexpressing plants compared with the wild type.Supplying exogenous C18:1 and C18:2 could rescue the mutant phenotype,suggesting that these FAs play an essential role in tolerance to heat stress.Transmission electron microscopy observations showed that heat stress seriously affected the membrane architecture in accD editing-defective mutants but not in accD-overexpressing plants.These results provide the first evidence that accD-C794 editing regulates FA biosynthesis for maintenance of membrane structural homeostasis under heat stress.展开更多
在包括物联网(Internet of Things,IoT)设备的绝大部分边缘计算应用中,基于互联网应用技术(通常被称为Web技术)开发的应用程序接口(Application Programming Interface,API)是设备与远程服务器进行信息交互的核心。相比传统的Web应用,...在包括物联网(Internet of Things,IoT)设备的绝大部分边缘计算应用中,基于互联网应用技术(通常被称为Web技术)开发的应用程序接口(Application Programming Interface,API)是设备与远程服务器进行信息交互的核心。相比传统的Web应用,大部分用户无法直接接触到边缘设备使用的API,使得其遭受的攻击相对较少。但随着物联网设备的普及,针对API的攻击逐渐成为热点。因此,文中提出了一种面向物联网服务的Web攻击向量检测方法,用于对物联网服务收到的Web流量进行检测,并挖掘出其中的恶意流量,从而为安全运营中心(Security Operation Center,SOC)提供安全情报。该方法在对超文本传输协议(Hypertext Transfer Protocol,HTTP)请求的文本序列进行特征抽取的基础上,针对API请求的报文格式相对固定的特点,结合双向长短期记忆网络(Bidirectional Long Short-Term Memory,BLSTM)实现对Web流量的攻击向量检测。实验结果表明,相比基于规则的Web应用防火墙(Web Application Firewall,WAF)和传统的机器学习方法,所提方法针对面向物联网服务API的攻击具有更好的识别能力。展开更多
基金financially supported by the National Natural Science Foundation of China(NSFC)(Grant No.51601054)the Natural Science Foundation of Hebei Province of China(Grant Nos.E2017202095 and E2016202100)+1 种基金the Plan Program for International S&T Cooperation Projects of Hebei Province of China(Grant No.17391004D)the Tianjin Science and Technology Support Program(Grant No.16YFZCGX00140)
文摘The effects of austempering temperature on microstructure and surface residual stress of carbidic austempered ductile iron （CADI） grinding balls were systematically investigated in this work. The microstructures were oberserved by optical metallography and analyized by X-ray diffraction. The surface residual stress measured by the cutting method is mainly composed of thermal stress and phase transformation stress.The thermal stress in grinding balls was determined by ANSYS simulation technique, and the surface phase transformation stress was obtained by subtracting the simulated surface thermal stress from the measured surface residual stress. Results show that all microstructures consist of ausferrite, white-bright zones （mixture of martensite and austenite）, nodular graphite, and carbides. The distribution of ausferrite shows uniform. With the increase of austempering temperature, the volume fraction and carbon content of austenite increase, whereas the amount of white-bright zone decreases. In addition, the surface residual stress increases with the increase of austempering temperature. Only the tension exists at the austempering temperature of 200 ℃, and the pressure exists at the austempering temperature of 220-260 °C. The thermal stress changes from the tension on the inside with the radius of 0-35 mm to the pressure on the outside with the radius of 35-62.5 mm, and the stress balance state presents at the radius of 35 mm. It is also found that the transformation stress is related to the content of carbon-rich austenite, and will reduce by 5.03 MPa accompanied with 1vol.% increase of the austenite.The thermal compressive stress and the transformation tensile stress on the surface both decrease with the increase of the austempering temperature.
基金supported by National Natural Science Foundation of China(No.92261109)Natural Science Foundation of Fujian Province(No.2020J05080)+3 种基金Project Funded by China Postdoctoral Science Foundation(No.2023M733496)Natural Science Foundation of Xiamen(No.3502Z20206080)Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(No.2021ZR110)Recruitment Program of Global Youth Experts,Youth Innovation Promotion Association CAS(No.2021302).
文摘Electron-deficient viologens are widely used as ligands or structure-directing agents(SDAs)to synthesize crystalline X-ray induced photochromic materials.Here,a new rational strategy of anion-directed fold-ing a flexible cation(H_(2)imb)^(2+)((H_(2)imb)^(2+)=di-protonated 2,3-bis(imidazolin-2-yl)-2,3-dimethylbutane)has been developed.Electron-donating Cl−and(ZnCl4)2−are used to direct folding a flexible electron-deficient(H_(2)imb)^(2+)cation.Three complexes(H_(2)imb)(NO_(3))2(1),(H_(2)imb)Cl2·H_(2)O(2),and(H_(2)imb)ZnCl4(3)have been synthesized in which(H_(2)imb)^(2+)crystallize in an anti-conformation,88.8°-gauche,and 51.8°-gauche,respectively.In contrary to X-ray silent complex 1,X-ray induced photochromism has been achieved in both complex 2 and 3.An intermolecular charge-transfer mechanism has been elucidated and the anion directed folding of(H_(2)imb)^(2+)has been validated to be critical to yield colored long-lived charge-separated states.
文摘Pyroptosis plays an important role in hemorrhagic stroke.Excessive endoplasmic reticulum stress can cause endoplasmic reticulum dysfunction and cellular pyroptosis by regulating the nucleotide-binding oligomerization domain and leucine-rich repeat pyrin domain-containing protein 3(NLRP3)pathway.However,the relationship between pyroptosis and endoplasmic reticulum stress after intraventricular hemorrhage is unclear.In this study,we established a mouse model of intraventricular hemorrhage and found pyroptosis and endoplasmic reticulum stress in brain tissue.Intraperitoneal injection of the selective GPR120 agonist TUG-891 inhibited endoplasmic reticulum stress,pyroptosis,and inflammation and protected neurons.The neuroprotective effect of TUG-891 appears related to inhibition of endoplasmic reticulum stress and pyroptosis activation.
基金supported by the National Natural Science Foundation of China(91317312 and 31900387)the Natural Science Foundation of Hunan Province(2020JJ4037 and 2021JJ40243).
文摘It has been reported that Arabidopsis chloroplast accD transcripts undergo RNA editing and that loss of accD-C794 RNA editing does not affect plant growth under normal conditions.To date,the exact biological role of accD-C794 editing has remained elusive.Here,we reveal an unexpected role for accD-C794 editing in response to heat stress.Loss of accD-C794 editing results in a yellow and dwarf phenotype with decreased chloroplast gene expression under heat stress,and artificial improvement of C794-edited accD gene expression enhances heat tolerance in Arabidopsis.These data suggest that accD-C794 editing confers heat tolerance in planta.We also found that treatment with the product of acetyl coenzyme A carboxylase(ACCase)could allay mutant phenotypic characteristics and showed that a mutation in the CAC3 gene for the a-subunit of ACCase was associated with dwarfism under heat stress.These observations indicate that defective accD-C794 editing may be intrinsic to reduced ACCase activity,thereby contributing to heat sensitivity.ACCase catalyzes the committed step of de novo fatty acid(FA)biosynthesis.FA content analysis revealed that unsaturated oleic(C18:1)and linoleic acids(C18:2)were low in the accD-C794 editing-defective mutant but high in the C794-edited accD-overexpressing plants compared with the wild type.Supplying exogenous C18:1 and C18:2 could rescue the mutant phenotype,suggesting that these FAs play an essential role in tolerance to heat stress.Transmission electron microscopy observations showed that heat stress seriously affected the membrane architecture in accD editing-defective mutants but not in accD-overexpressing plants.These results provide the first evidence that accD-C794 editing regulates FA biosynthesis for maintenance of membrane structural homeostasis under heat stress.
文摘在包括物联网(Internet of Things,IoT)设备的绝大部分边缘计算应用中,基于互联网应用技术(通常被称为Web技术)开发的应用程序接口(Application Programming Interface,API)是设备与远程服务器进行信息交互的核心。相比传统的Web应用,大部分用户无法直接接触到边缘设备使用的API,使得其遭受的攻击相对较少。但随着物联网设备的普及,针对API的攻击逐渐成为热点。因此,文中提出了一种面向物联网服务的Web攻击向量检测方法,用于对物联网服务收到的Web流量进行检测,并挖掘出其中的恶意流量,从而为安全运营中心(Security Operation Center,SOC)提供安全情报。该方法在对超文本传输协议(Hypertext Transfer Protocol,HTTP)请求的文本序列进行特征抽取的基础上,针对API请求的报文格式相对固定的特点,结合双向长短期记忆网络(Bidirectional Long Short-Term Memory,BLSTM)实现对Web流量的攻击向量检测。实验结果表明,相比基于规则的Web应用防火墙(Web Application Firewall,WAF)和传统的机器学习方法,所提方法针对面向物联网服务API的攻击具有更好的识别能力。
