The loss tangent and storage modulus of cement mortar containing treated silica fume and styrene-acrylic are measured. Shaking table tests on three groups of 1/4 models of high damping concrete frames are conducted to...The loss tangent and storage modulus of cement mortar containing treated silica fume and styrene-acrylic are measured. Shaking table tests on three groups of 1/4 models of high damping concrete frames are conducted to compare the effects of reducing vibration. A relationship between the viscosity coefficient of high damping concrete and the damping coefficient of structure is established by analyzing dynamic parameters like damping ratio and frequency, and comparing responses of relative displacement and absolute acceleration. Surface treatment of silica fume and styrene-acrylic emulsion prior to incorporation in a cement mortar increases the loss tangent of the resulting composite by 40-400% as compared to the cement mortar without any admixtures, and the damping ratio of the reinforced concrete is raised by 7%-9%. In addition, a theoretical method of determining the viscosity coefficient of the material on the basis of shaking table test results is put forward.展开更多
The T-square fractal two-dimensional phononic crystal model is presented in this article.A comprehensive study is performed for the Bragg scattering and locally resonant fractal phononic crystal.We find that the band ...The T-square fractal two-dimensional phononic crystal model is presented in this article.A comprehensive study is performed for the Bragg scattering and locally resonant fractal phononic crystal.We find that the band structures of the fractal and non-fractal phononic crystals at the same filling ratio are quite different through using the finite element method.The fractal design has an important impact on the band structures of the two-dimensional phononic crystals.展开更多
The mechanism of ultrasonic wire wedge bonding, one of the die/chip interconnection methods, was investigated based on the characteristics of the ultrasonic wire bonding joints. The Al-1%Si wire of 25 μm in diameter ...The mechanism of ultrasonic wire wedge bonding, one of the die/chip interconnection methods, was investigated based on the characteristics of the ultrasonic wire bonding joints. The Al-1%Si wire of 25 μm in diameter was bonded on Au/Ni/Cu pad and the joint cross-section was analyzed by scanning electron microscopy （SEM） and energy-dispersive X-ray spectroscopy （EDX）. The results indicated that it is irregular for the ultrasonic bond formation, non-welded at the centre but joining well at the periphery, especially at the heel and toe of the joint. Furthermore, the diffusion and/or reaction at the cross-section interface are not clear at C-zone, while there exists a strip layer microstructure at P-zone, and the composition is 78.96 at. pct Al and 14.88 at. pct Ni, close to the Al3Ni intermetallic compound. All these observations are tentatively ascribed to the plastic flow enhanced by ultrasonic vibration and repeated cold deformation driving interdiffusion between AI and Ni at bond interface.展开更多
Formation of AuSnx intermetallic compounds （IMCs） in laser reflowed solder joints was investigated. The results showed that few IMCs formed at the solder/0. 1μm Au interface. Needlelike AuSn4 IMCs were observed at ...Formation of AuSnx intermetallic compounds （IMCs） in laser reflowed solder joints was investigated. The results showed that few IMCs formed at the solder/0. 1μm Au interface. Needlelike AuSn4 IMCs were observed at the solder/0.5μm Au interface. In Sn-2.0Ag-O,75Cu-3,0Bi and Sn-3.5Ag-O.75Cu solder joints, when the laser input energy was increased, AuSn4 IMCs changed .from a layer to needlelike or dendritic distribution at the solder/0.9μm Au interface. As for the solder joints with 4.0 μm thickness of Au surface finish on pads, AuSn4 , AuSnx, AuSn IMCs, and Au2Sn phases formed at the interface. Moreover, the content of AuSnx IMCs, such as, AuSn4 and AuSn2, which contained high Sn concentration, would become larger as the laser input energy increased. In the Sn-37Pb solder joints with 0.9 μm or 4.0 μm thickness of the Au surface finish on pads, AuSn4 IMCs were in netlike distribution. The interspaces between them were filled with Pb-rich phases.展开更多
In this paper, an uplink power control problem is considered for code division multiple access （CDMA） systems. A distributed algorithm is proposed based on linear quadratic optimal control theory. The proposed schem...In this paper, an uplink power control problem is considered for code division multiple access （CDMA） systems. A distributed algorithm is proposed based on linear quadratic optimal control theory. The proposed scheme minimizes the sum of the power and the error of signal-to-interference ratio （SIR）. A power controller is designed by constructing an optimization problem of a stochastic linear quadratic type in Krein space and solving a Kalman filter problem.展开更多
An electrochemical method for simultaneous determination of ascorbic acid（AA）, dopamine（DA） and uric acid（UA） was developed based on RGO-Ag/PANI modified glassy carbon electrode（RGO-Ag/PANI/GCE, RGO= reduced gr...An electrochemical method for simultaneous determination of ascorbic acid（AA）, dopamine（DA） and uric acid（UA） was developed based on RGO-Ag/PANI modified glassy carbon electrode（RGO-Ag/PANI/GCE, RGO= reduced graphene oxide, PANI=polyaniline）. Owing to the synergetic effect among RGO, Ag and PANI, the RGO-Ag/PANI based sensor not only improved the electrochemically catalytic oxidation ofAA, DA and UA, but also resolved the overlapping anodic peaks. Under the optimized conditions, the calibration curves were obtained in the concentration ranges of 50--1000, 5--200 and 20--350 ttmol/L, and the detection limits（S/N=3） of 0.5, 0.2 and 0.2 ~tmol/L were obtained for AA, DA, and UA, respectively, in neutral phosphate buffer solutions（PBS）. The RGO-Ag/PANI/GCE sensor was successfully applied to the determination of AA, DA, and UA in bovine serum samples and showed high selectivity, sensitivity, and reproducibility.展开更多
Based on an innovation analysis method in the Krein space, a sufficient and necessary condition is given for the existence of the solution of H∞ control problem for a linear continuoustime system with multiple delays...Based on an innovation analysis method in the Krein space, a sufficient and necessary condition is given for the existence of the solution of H∞ control problem for a linear continuoustime system with multiple delays. By introducing a re-organized innovation sequence, the H∞ control problem with delayed measurements is converted into a linear quadratic (LQ) problem and a delayfree H2 estimation problem in the Krein space. The controller is given in terms of two forward Riccati equations and a backward Riccati equation.展开更多
H-infinity control problem for linear discrete-time systems with instantaneous and delayed measurements is studied. A necessary and sufficient condition for the existence of the H-infinity controller is derived by app...H-infinity control problem for linear discrete-time systems with instantaneous and delayed measurements is studied. A necessary and sufficient condition for the existence of the H-infinity controller is derived by applying reorganized innovation analysis approach in Krein space. The measurement-feedback controller is designed by performing two Riccati equations. The presented approach does not require the state augmentation.展开更多
In a recent study in Science,Nejmen et al.provide the first comprehensive characterization of the tumor microbiome.Their data reveal that the microbiome mostly resides intracellularly in both tumor and immune cells,an...In a recent study in Science,Nejmen et al.provide the first comprehensive characterization of the tumor microbiome.Their data reveal that the microbiome mostly resides intracellularly in both tumor and immune cells,and that its composition varies with tumor type and subtype,smoking status,and immunotherapy response.展开更多
The tumor suppressor p53 transactivates the expression of multiple genes to exert its multifaceted functions and ultimately maintains genome stability.Thus,cancer cells develop various mechanisms to diminish p53 expre...The tumor suppressor p53 transactivates the expression of multiple genes to exert its multifaceted functions and ultimately maintains genome stability.Thus,cancer cells develop various mechanisms to diminish p53 expression and bypass the cell cycle checkpoint.In this study,we identified the gene encoding RNAbinding protein cytoplasmic polyadenylation element-binding protein 2(CPEB2)as a p53 target.In turn,CPEB2 decreases p53 messenger RNA stability and translation to fine-tune p53 level.Specifically,we showed that CPEB2 binds the cytoplasmic polyadenylation elements in the p5330-untranslated region,and the RNA recognition motif and zinc finger(ZF)domains of CPEB2 are required for this binding.Furthermore,we found that CPEB2 was upregulated in renal cancer tissues and promotes the renal cancer cell proliferation and migration.The oncogenic effect of CPEB2 is partially dependent on negative feedback regulation of p53.Overall,we identify a novel regulatory feedback loop between p53 and CPEB2 and demonstrate that CPEB2 promotes tumor progression by inactivating p53,suggesting that CPEB2 is a potential therapeutic target in human renal cancer.展开更多
基金the National Natumal Science Foundation of China(No.50608025)Guangdong Provincial Natural Science Foundation of(No.05300894)China Postdoctoral Science Foundation(No.20060390804)
文摘The loss tangent and storage modulus of cement mortar containing treated silica fume and styrene-acrylic are measured. Shaking table tests on three groups of 1/4 models of high damping concrete frames are conducted to compare the effects of reducing vibration. A relationship between the viscosity coefficient of high damping concrete and the damping coefficient of structure is established by analyzing dynamic parameters like damping ratio and frequency, and comparing responses of relative displacement and absolute acceleration. Surface treatment of silica fume and styrene-acrylic emulsion prior to incorporation in a cement mortar increases the loss tangent of the resulting composite by 40-400% as compared to the cement mortar without any admixtures, and the damping ratio of the reinforced concrete is raised by 7%-9%. In addition, a theoretical method of determining the viscosity coefficient of the material on the basis of shaking table test results is put forward.
基金Project supported by the Technology Research and Development Funds of Shenzhen City,China (Grant No. JC201005260129A)
文摘The T-square fractal two-dimensional phononic crystal model is presented in this article.A comprehensive study is performed for the Bragg scattering and locally resonant fractal phononic crystal.We find that the band structures of the fractal and non-fractal phononic crystals at the same filling ratio are quite different through using the finite element method.The fractal design has an important impact on the band structures of the two-dimensional phononic crystals.
文摘The mechanism of ultrasonic wire wedge bonding, one of the die/chip interconnection methods, was investigated based on the characteristics of the ultrasonic wire bonding joints. The Al-1%Si wire of 25 μm in diameter was bonded on Au/Ni/Cu pad and the joint cross-section was analyzed by scanning electron microscopy （SEM） and energy-dispersive X-ray spectroscopy （EDX）. The results indicated that it is irregular for the ultrasonic bond formation, non-welded at the centre but joining well at the periphery, especially at the heel and toe of the joint. Furthermore, the diffusion and/or reaction at the cross-section interface are not clear at C-zone, while there exists a strip layer microstructure at P-zone, and the composition is 78.96 at. pct Al and 14.88 at. pct Ni, close to the Al3Ni intermetallic compound. All these observations are tentatively ascribed to the plastic flow enhanced by ultrasonic vibration and repeated cold deformation driving interdiffusion between AI and Ni at bond interface.
基金This study was financially supported by National Natural Science Foundation of China （No.50675047）.
文摘Formation of AuSnx intermetallic compounds （IMCs） in laser reflowed solder joints was investigated. The results showed that few IMCs formed at the solder/0. 1μm Au interface. Needlelike AuSn4 IMCs were observed at the solder/0.5μm Au interface. In Sn-2.0Ag-O,75Cu-3,0Bi and Sn-3.5Ag-O.75Cu solder joints, when the laser input energy was increased, AuSn4 IMCs changed .from a layer to needlelike or dendritic distribution at the solder/0.9μm Au interface. As for the solder joints with 4.0 μm thickness of Au surface finish on pads, AuSn4 , AuSnx, AuSn IMCs, and Au2Sn phases formed at the interface. Moreover, the content of AuSnx IMCs, such as, AuSn4 and AuSn2, which contained high Sn concentration, would become larger as the laser input energy increased. In the Sn-37Pb solder joints with 0.9 μm or 4.0 μm thickness of the Au surface finish on pads, AuSn4 IMCs were in netlike distribution. The interspaces between them were filled with Pb-rich phases.
基金the National Natural Science Foundation of China(No.60574016).
文摘In this paper, an uplink power control problem is considered for code division multiple access （CDMA） systems. A distributed algorithm is proposed based on linear quadratic optimal control theory. The proposed scheme minimizes the sum of the power and the error of signal-to-interference ratio （SIR）. A power controller is designed by constructing an optimization problem of a stochastic linear quadratic type in Krein space and solving a Kalman filter problem.
基金Supported by the Natural Science Foundation of Liaoning Province, China（No.2015020197） and the National Natural Science Foundation of China（No.51403130）.
文摘An electrochemical method for simultaneous determination of ascorbic acid（AA）, dopamine（DA） and uric acid（UA） was developed based on RGO-Ag/PANI modified glassy carbon electrode（RGO-Ag/PANI/GCE, RGO= reduced graphene oxide, PANI=polyaniline）. Owing to the synergetic effect among RGO, Ag and PANI, the RGO-Ag/PANI based sensor not only improved the electrochemically catalytic oxidation ofAA, DA and UA, but also resolved the overlapping anodic peaks. Under the optimized conditions, the calibration curves were obtained in the concentration ranges of 50--1000, 5--200 and 20--350 ttmol/L, and the detection limits（S/N=3） of 0.5, 0.2 and 0.2 ~tmol/L were obtained for AA, DA, and UA, respectively, in neutral phosphate buffer solutions（PBS）. The RGO-Ag/PANI/GCE sensor was successfully applied to the determination of AA, DA, and UA in bovine serum samples and showed high selectivity, sensitivity, and reproducibility.
基金国家自然科学基金，National Outstanding Youth Science Foundation of P.R.China
文摘Based on an innovation analysis method in the Krein space, a sufficient and necessary condition is given for the existence of the solution of H∞ control problem for a linear continuoustime system with multiple delays. By introducing a re-organized innovation sequence, the H∞ control problem with delayed measurements is converted into a linear quadratic (LQ) problem and a delayfree H2 estimation problem in the Krein space. The controller is given in terms of two forward Riccati equations and a backward Riccati equation.
基金This work was supported by the National Natural Science Foundation of China(No.60174017) the National Outstanding Youth Science Foundation of China(No.69925308).
文摘H-infinity control problem for linear discrete-time systems with instantaneous and delayed measurements is studied. A necessary and sufficient condition for the existence of the H-infinity controller is derived by applying reorganized innovation analysis approach in Krein space. The measurement-feedback controller is designed by performing two Riccati equations. The presented approach does not require the state augmentation.
基金funded by the National Nature Science Foundation of China(No.31301131,31741084 and 31871389)Basic Science Fundation of Science and technology innovation Commission in Shenzhen(No.JCYJ20170811154452255).
文摘In a recent study in Science,Nejmen et al.provide the first comprehensive characterization of the tumor microbiome.Their data reveal that the microbiome mostly resides intracellularly in both tumor and immune cells,and that its composition varies with tumor type and subtype,smoking status,and immunotherapy response.
基金supported by grants from the National Natural Science Foundation of China(81972377,82025027,31301131,81972723)the Science and Technology Project of Xuzhou(KC19064)+1 种基金the Social Development Project of Jiangsu Province(BE2019644)the Natural Science Foundation of the Jiangsu Higher Education Institutions(18KJA320012)。
文摘The tumor suppressor p53 transactivates the expression of multiple genes to exert its multifaceted functions and ultimately maintains genome stability.Thus,cancer cells develop various mechanisms to diminish p53 expression and bypass the cell cycle checkpoint.In this study,we identified the gene encoding RNAbinding protein cytoplasmic polyadenylation element-binding protein 2(CPEB2)as a p53 target.In turn,CPEB2 decreases p53 messenger RNA stability and translation to fine-tune p53 level.Specifically,we showed that CPEB2 binds the cytoplasmic polyadenylation elements in the p5330-untranslated region,and the RNA recognition motif and zinc finger(ZF)domains of CPEB2 are required for this binding.Furthermore,we found that CPEB2 was upregulated in renal cancer tissues and promotes the renal cancer cell proliferation and migration.The oncogenic effect of CPEB2 is partially dependent on negative feedback regulation of p53.Overall,we identify a novel regulatory feedback loop between p53 and CPEB2 and demonstrate that CPEB2 promotes tumor progression by inactivating p53,suggesting that CPEB2 is a potential therapeutic target in human renal cancer.
