The enhancement of interface bonding between cement and polymerand the structural reticula- tion of the water-soluble polymer areproposed to minimize the shortening of the mechanical properties ofmacro-de- fect-free(M...The enhancement of interface bonding between cement and polymerand the structural reticula- tion of the water-soluble polymer areproposed to minimize the shortening of the mechanical properties ofmacro-de- fect-free(MDF)cement based composites at high relativehumidity. The MDF composites incorporated with vari- ouscross-coupling agents studied experimentally. The results show thatthe MDF composites modified with small amounts of cross-couplingagent had raised mechanical properties, but it is more important thatthe modified MDF composites had a significant increase in waterresistance compared to the original one.展开更多
Very high cycle fatigue（VHCF） properties of a low temperature tempering bearing steel GCr15 with smooth and hole-defect specimens are studied by employing a rotary bending test machine with frequency of 52.5 Hz.Both...Very high cycle fatigue（VHCF） properties of a low temperature tempering bearing steel GCr15 with smooth and hole-defect specimens are studied by employing a rotary bending test machine with frequency of 52.5 Hz.Both smooth and hole-defect specimens break in VHCF regime with some difference in fatigue crack initiation.For smooth specimens,a fine granular area（FGA） is observed near the grain boundary in the fracture surface of the specimens broken after 10~7 cycles. But no FGA is observed in the hole-defect specimens broken in VHCF regime,and the VHCF crack does not initiate from the small hole at the surface as it does at low or high cycle fatigue regime. Internal stress is employed to explain the VHCF behavior of these two types of specimens.At last,an advanced dislocation model based on Tanaka and Mura model is proposed to illustrate the internal stress process and to predict fatigue crack initiation life with FGA observed in the fracture region.展开更多
An E1B-defective adenovirus named r1/Ad was constructed by homologous recombination. The construction, selection and propagation of recombinant virus was done in the human embryonic kidney 293 cells (HEK293). Thein vi...An E1B-defective adenovirus named r1/Ad was constructed by homologous recombination. The construction, selection and propagation of recombinant virus was done in the human embryonic kidney 293 cells (HEK293). Thein vitro study demonstrated that the recombinant virus has the ability to replicate in and lyse some p53-deficient human tumor cells such as the human glioblastoma tumor cells (U251) and human bladder tumer cells (EJ) but not in the normal cells with functional p53 such as the human fibroblast cells (MRC-5). Also, based on the cytopathic effect (CPE), it was demonstrated that the U251 cells were more sensitive to the infection of r1/Ad than that of EJ cells under identical conditions. In this paper, it was found that r1/Ad could be very useful in studying thein vitro selective replication of E1B-defective adenovirus. This may help to determine the safety of using any E1B-defective adenoviruses in cancer gene therapy. Key words E1B-defective adenovirus - cytopathic effect - cancer gene therapy CLC number Q78 Foundation item: Supported by the National Natural Science Foundation of China (3988003)Biography: Xue Feng (1978-), male, Master, research direction: cancer gene therapy by recombinant virus.展开更多
The influence of a deep-level-defect（DLD） band formed in a heavily Mg-doped GaN contact layer on the performance of Ni/Au contact to p-GaN is investigated. The thin heavily Mg-doped GaN（p^＋＋-GaN） contact layer w...The influence of a deep-level-defect（DLD） band formed in a heavily Mg-doped GaN contact layer on the performance of Ni/Au contact to p-GaN is investigated. The thin heavily Mg-doped GaN（p^＋＋-GaN） contact layer with DLD band can effectively improve the performance of Ni/Au ohmic contact to p-GaN. The temperature-dependent I–V measurement shows that the variable-range hopping（VRH） transportation through the DLD band plays a dominant role in the ohmic contact. The thickness and Mg/Ga flow ratio of p^＋＋-GaN contact layer have a significant effect on ohmic contact by controlling the Mg impurity doping and the formation of a proper DLD band. When the thickness of the p^＋＋-GaN contact layer is 25 nm thick and the Mg/Ga flow rate ratio is 10.29%, an ohmic contact with low specific contact resistivity of 6.97×10^-4Ω·cm^2 is achieved.展开更多
The continuous descaling and cold rolling mill（ CDCM） is renow ned for its high capacity and high speed,which makes it very difficult to manually check the surface quality of steel strips. A surface-defect online de...The continuous descaling and cold rolling mill（ CDCM） is renow ned for its high capacity and high speed,which makes it very difficult to manually check the surface quality of steel strips. A surface-defect online detector and its components,which are employed in a CDCM at Baosteel,are introduced,including the electrical,imaging,processing and softw are systems. To evaluate the effectiveness of the application of this detector,and to reduce the number of false alarms,the optimal number of defect samples is determined,pre- and post-processing rules are established,and talking-voice and color-changing alarms are employed.展开更多
KH2PO4 crystal is a crucial optical component of inertial confinement fusion. Modulation of an incident laser by surface micro-defects will induce the growth of surface damage, which largely restricts the enhancement ...KH2PO4 crystal is a crucial optical component of inertial confinement fusion. Modulation of an incident laser by surface micro-defects will induce the growth of surface damage, which largely restricts the enhancement of the laser induced damage threshold. The modulation of an incident laser by using different kinds of surface defects are simulated by employing the three-dimensional finite-difference time-domain method. The results indicate that after the modulation of surface defects, the light intensity distribution inside the crystal is badly distorted, with the light intensity enhanced symmetrically. The relations between modulation properties and defect geometries （e.g., width, morphology, and depth of defects） are quite different for different defects. The modulation action is most obvious when the width of surface defects reaches 1.064 p-m. For defects with smooth morphology, such as spherical pits, the degree of modulation is the smallest and the light intensity distribution seems relatively uniform. The degree of modulation increases rapidly with the increase of the depth of surface defects and becomes stable when the depth reaches a critical value. The critical depth is 1.064 μm for cuboid pits and radial cracks, while for ellipsoidal pits the value depends on both the width and the length of the defects.展开更多
背景:锌基合金医用植入材料有优异的力学性能、完全可降解性、良好的生物相容性,主要用于骨科植入物、心血管支架、胆管支架、气管支架、神经导管等。目的:综述可降解锌基合金应用于骨缺损修复的研究进展,展望锌基材料可期研究方向与成...背景:锌基合金医用植入材料有优异的力学性能、完全可降解性、良好的生物相容性,主要用于骨科植入物、心血管支架、胆管支架、气管支架、神经导管等。目的:综述可降解锌基合金应用于骨缺损修复的研究进展,展望锌基材料可期研究方向与成果。方法:检索PubMed、Web of Science、万方及中国知网数据库,选择各数据库建库至2023年6月收录的各类可降解锌基合金用于骨植入材料研究的相关文献,对生物可降解锌基合金的基本特性进行概述,对锌基合金促进骨组织修复作用进行梳理和归纳总结,讨论当前的研究热点与不足。结果与结论:①锌基合金具备良好的生物相容性,以锌基合金为基体材料,借助支架结构构建技术和涂层优化工艺将有效提高锌基合金的骨传导性,并且使其降解产物具备高效骨诱导性,以调控成骨、破骨细胞的基因表达,促进骨缺损后的修复重建;②然而在锌基合金优化的研究中,涂层工艺相对不足,增材负载技术尚缺乏;③锌基合金拥有良好的机械、生物特性,通过特殊工艺可增加材料的骨传导性、骨诱导性以有效提高其促进骨修复重建能力,并有望进一步实现个性化移植材料的研发。优化涂层与增材负载等技术融合于锌基合金的研究有待进一步探讨。展开更多
背景:诱导膜技术(Masquelet技术)是一种两阶段手术重建大段骨缺损的新技术,在临床中应用越来越广泛。然而,该技术修复骨缺损的机制尚不十分明确。目的:就诱导膜技术的产生背景、修复机制和优势、诱导膜的特征、膜-植骨通讯、动物模型的...背景:诱导膜技术(Masquelet技术)是一种两阶段手术重建大段骨缺损的新技术,在临床中应用越来越广泛。然而,该技术修复骨缺损的机制尚不十分明确。目的:就诱导膜技术的产生背景、修复机制和优势、诱导膜的特征、膜-植骨通讯、动物模型的选择、骨水泥的种类、形貌、所载抗生素对诱导膜的影响、固定方式的选择和骨组织工程材料方面进行综述,以期为未来临界尺寸骨缺损的治疗和诱导膜技术的改进提供新思路。方法:检索PubMed、Web of Science数据库和中国知网(CNKI)中1986-2024年出版的文献,共检索到890篇参考文献。按与诱导膜技术基础研究相关的入选标准进行人工筛选和分析,排除与主题相关性差和重复的文献,纳入研究的文献包括实验类研究原著、综述、荟萃分析等,最终纳入72篇文献进行归纳和分析。结果与结论:①诱导膜技术修复骨缺损的机制尚不明确,但膜和植骨两者缺一不可;②诱导膜是一种富含多种骨形成相关细胞、生长因子和血管的分层较明显组织,其血管化和生长因子的分泌随时间而动态变化;③对于动物模型选择,从解剖结构、负重模式和骨重塑的相似度来讲,羊更为接近;从饲养成本和难度、造模周期来讲,大鼠更合适;④聚甲基丙烯酸甲酯(PMMA)骨水泥不是唯一可以用做诱导生物膜的材料,可能有更加合适的材料可以诱导出更高质量的生物膜;骨水泥负载抗生素的剂量(主要是万古霉素)为每40 g的聚甲基丙烯酸甲酯负载1-4 g抗生素;⑤对于动物(特别是大鼠)固定方式而言,钢板使用更为广泛,固定方式更加可靠,可重复性更高;⑥未来可能会有新的材料替代自体骨促进Masquelet技术的骨修复能力。展开更多
文摘The enhancement of interface bonding between cement and polymerand the structural reticula- tion of the water-soluble polymer areproposed to minimize the shortening of the mechanical properties ofmacro-de- fect-free(MDF)cement based composites at high relativehumidity. The MDF composites incorporated with vari- ouscross-coupling agents studied experimentally. The results show thatthe MDF composites modified with small amounts of cross-couplingagent had raised mechanical properties, but it is more important thatthe modified MDF composites had a significant increase in waterresistance compared to the original one.
基金supported by the National Natural Science Foundation of China(11021262 and 11172304)the National Basic Research Program of China (2012CB937500)
文摘Very high cycle fatigue（VHCF） properties of a low temperature tempering bearing steel GCr15 with smooth and hole-defect specimens are studied by employing a rotary bending test machine with frequency of 52.5 Hz.Both smooth and hole-defect specimens break in VHCF regime with some difference in fatigue crack initiation.For smooth specimens,a fine granular area（FGA） is observed near the grain boundary in the fracture surface of the specimens broken after 10~7 cycles. But no FGA is observed in the hole-defect specimens broken in VHCF regime,and the VHCF crack does not initiate from the small hole at the surface as it does at low or high cycle fatigue regime. Internal stress is employed to explain the VHCF behavior of these two types of specimens.At last,an advanced dislocation model based on Tanaka and Mura model is proposed to illustrate the internal stress process and to predict fatigue crack initiation life with FGA observed in the fracture region.
文摘An E1B-defective adenovirus named r1/Ad was constructed by homologous recombination. The construction, selection and propagation of recombinant virus was done in the human embryonic kidney 293 cells (HEK293). Thein vitro study demonstrated that the recombinant virus has the ability to replicate in and lyse some p53-deficient human tumor cells such as the human glioblastoma tumor cells (U251) and human bladder tumer cells (EJ) but not in the normal cells with functional p53 such as the human fibroblast cells (MRC-5). Also, based on the cytopathic effect (CPE), it was demonstrated that the U251 cells were more sensitive to the infection of r1/Ad than that of EJ cells under identical conditions. In this paper, it was found that r1/Ad could be very useful in studying thein vitro selective replication of E1B-defective adenovirus. This may help to determine the safety of using any E1B-defective adenoviruses in cancer gene therapy. Key words E1B-defective adenovirus - cytopathic effect - cancer gene therapy CLC number Q78 Foundation item: Supported by the National Natural Science Foundation of China (3988003)Biography: Xue Feng (1978-), male, Master, research direction: cancer gene therapy by recombinant virus.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61474110,61377020,61376089,61223005,and 61176126)the National Science Fund for Distinguished Young Scholars of China(Grant No.60925017)+1 种基金One Hundred Person Project of the Chinese Academy of Sciencesthe Basic Research Project of Jiangsu Province,China(Grant No.BK20130362)
文摘The influence of a deep-level-defect（DLD） band formed in a heavily Mg-doped GaN contact layer on the performance of Ni/Au contact to p-GaN is investigated. The thin heavily Mg-doped GaN（p^＋＋-GaN） contact layer with DLD band can effectively improve the performance of Ni/Au ohmic contact to p-GaN. The temperature-dependent I–V measurement shows that the variable-range hopping（VRH） transportation through the DLD band plays a dominant role in the ohmic contact. The thickness and Mg/Ga flow ratio of p^＋＋-GaN contact layer have a significant effect on ohmic contact by controlling the Mg impurity doping and the formation of a proper DLD band. When the thickness of the p^＋＋-GaN contact layer is 25 nm thick and the Mg/Ga flow rate ratio is 10.29%, an ohmic contact with low specific contact resistivity of 6.97×10^-4Ω·cm^2 is achieved.
文摘The continuous descaling and cold rolling mill（ CDCM） is renow ned for its high capacity and high speed,which makes it very difficult to manually check the surface quality of steel strips. A surface-defect online detector and its components,which are employed in a CDCM at Baosteel,are introduced,including the electrical,imaging,processing and softw are systems. To evaluate the effectiveness of the application of this detector,and to reduce the number of false alarms,the optimal number of defect samples is determined,pre- and post-processing rules are established,and talking-voice and color-changing alarms are employed.
基金Project supported by the National Natural Science Foundation of China (Grant No. 50875066)
文摘KH2PO4 crystal is a crucial optical component of inertial confinement fusion. Modulation of an incident laser by surface micro-defects will induce the growth of surface damage, which largely restricts the enhancement of the laser induced damage threshold. The modulation of an incident laser by using different kinds of surface defects are simulated by employing the three-dimensional finite-difference time-domain method. The results indicate that after the modulation of surface defects, the light intensity distribution inside the crystal is badly distorted, with the light intensity enhanced symmetrically. The relations between modulation properties and defect geometries （e.g., width, morphology, and depth of defects） are quite different for different defects. The modulation action is most obvious when the width of surface defects reaches 1.064 p-m. For defects with smooth morphology, such as spherical pits, the degree of modulation is the smallest and the light intensity distribution seems relatively uniform. The degree of modulation increases rapidly with the increase of the depth of surface defects and becomes stable when the depth reaches a critical value. The critical depth is 1.064 μm for cuboid pits and radial cracks, while for ellipsoidal pits the value depends on both the width and the length of the defects.
文摘背景:锌基合金医用植入材料有优异的力学性能、完全可降解性、良好的生物相容性,主要用于骨科植入物、心血管支架、胆管支架、气管支架、神经导管等。目的:综述可降解锌基合金应用于骨缺损修复的研究进展,展望锌基材料可期研究方向与成果。方法:检索PubMed、Web of Science、万方及中国知网数据库,选择各数据库建库至2023年6月收录的各类可降解锌基合金用于骨植入材料研究的相关文献,对生物可降解锌基合金的基本特性进行概述,对锌基合金促进骨组织修复作用进行梳理和归纳总结,讨论当前的研究热点与不足。结果与结论:①锌基合金具备良好的生物相容性,以锌基合金为基体材料,借助支架结构构建技术和涂层优化工艺将有效提高锌基合金的骨传导性,并且使其降解产物具备高效骨诱导性,以调控成骨、破骨细胞的基因表达,促进骨缺损后的修复重建;②然而在锌基合金优化的研究中,涂层工艺相对不足,增材负载技术尚缺乏;③锌基合金拥有良好的机械、生物特性,通过特殊工艺可增加材料的骨传导性、骨诱导性以有效提高其促进骨修复重建能力,并有望进一步实现个性化移植材料的研发。优化涂层与增材负载等技术融合于锌基合金的研究有待进一步探讨。
文摘背景:诱导膜技术(Masquelet技术)是一种两阶段手术重建大段骨缺损的新技术,在临床中应用越来越广泛。然而,该技术修复骨缺损的机制尚不十分明确。目的:就诱导膜技术的产生背景、修复机制和优势、诱导膜的特征、膜-植骨通讯、动物模型的选择、骨水泥的种类、形貌、所载抗生素对诱导膜的影响、固定方式的选择和骨组织工程材料方面进行综述,以期为未来临界尺寸骨缺损的治疗和诱导膜技术的改进提供新思路。方法:检索PubMed、Web of Science数据库和中国知网(CNKI)中1986-2024年出版的文献,共检索到890篇参考文献。按与诱导膜技术基础研究相关的入选标准进行人工筛选和分析,排除与主题相关性差和重复的文献,纳入研究的文献包括实验类研究原著、综述、荟萃分析等,最终纳入72篇文献进行归纳和分析。结果与结论:①诱导膜技术修复骨缺损的机制尚不明确,但膜和植骨两者缺一不可;②诱导膜是一种富含多种骨形成相关细胞、生长因子和血管的分层较明显组织,其血管化和生长因子的分泌随时间而动态变化;③对于动物模型选择,从解剖结构、负重模式和骨重塑的相似度来讲,羊更为接近;从饲养成本和难度、造模周期来讲,大鼠更合适;④聚甲基丙烯酸甲酯(PMMA)骨水泥不是唯一可以用做诱导生物膜的材料,可能有更加合适的材料可以诱导出更高质量的生物膜;骨水泥负载抗生素的剂量(主要是万古霉素)为每40 g的聚甲基丙烯酸甲酯负载1-4 g抗生素;⑤对于动物(特别是大鼠)固定方式而言,钢板使用更为广泛,固定方式更加可靠,可重复性更高;⑥未来可能会有新的材料替代自体骨促进Masquelet技术的骨修复能力。
