This paper presents an analytical solution for the thermoelastic stress in a typical in-plane＇s thin-film micro- thermoelectric cooling device under different operating con- ditions. The distributions of the permissi...This paper presents an analytical solution for the thermoelastic stress in a typical in-plane＇s thin-film micro- thermoelectric cooling device under different operating con- ditions. The distributions of the permissible temperature fields in multilayered thin-films are analytically obtained, and the characteristics, including maximum temperature dif- ference and maximum refrigerating output of the thermo- electric device, are discussed for two operating conditions. Analytical expressions of the thermoelastic stresses in the layered thermoelectric thin-films induced by the tempera- ture difference are formulated based on the theory of mul- tilayer system. The results demonstrate that, the geometric dimension is a significant factor which remarkably affects the thermoelastic stresses. The stress distributions in layers of semiconductor thermoelements, insulating and support- ing membrane show distinctly different features. The present work may profitably guide the optimization design of high- efficiency micro-thermoelectric cooling devices.展开更多
Along with the consumption increase of the petroleum products, more countries have transferred their attentions to the offshore fields, especially the deepwater oil and gas reserves. For deepwater exploitation, the ri...Along with the consumption increase of the petroleum products, more countries have transferred their attentions to the offshore fields, especially the deepwater oil and gas reserves. For deepwater exploitation, the risers must be installed to act as the conduits connecting surface platforms to subsea facilities. In this paper, the typical risers sorted by different classes are introduced, and the correspondent installation methods are presented. By investigating the recent projects performed in the deepwater hot spots, and combining the challenges of HYSY20 l for riser installation, a lifting device developed for assisting riser installation is proposed and detailed to satisfy the installation of deepwater risers in the LW3-1 Gas Field of 1500 m in the South China Sea. Tests on both the functions and performances of such a new system exhibit the satisfaction of meeting all challenging requirements of HYSY201 for application to riser installation in waters up to a depth of 3000 m in the South China Sea.展开更多
The existence and propagation of transverse surface waves in piezoelectric coupled solids is investigated, in which perfect bonding between a metal/dielectric substrate and a piezoelectric layer of finite-thickness is...The existence and propagation of transverse surface waves in piezoelectric coupled solids is investigated, in which perfect bonding between a metal/dielectric substrate and a piezoelectric layer of finite-thickness is assumed. Dis- persion equations relating phase velocity to material con- stants for the existence of various modes are obtained in a simple mathematical form for a piezoelectric material of class 6mm. It is discovered and proved by numerical examples in this paper that a novel Bleustein-Gulyaev （B-G） type of transverse surface wave can exist in such piezoelectric cou- pled solid media when the bulk-shear-wave velocity in the substrate is less than that in the piezoelectric layer but greater than the corresponding B-G wave velocity in the same pie- zoelectric material with an electroded surface. Such a wave does not exist in such layered structures in the absence of pie- zoelectricity. The mode shapes for displacement and electric potential in the piezoelectric layer are obtained and discussed theoretically. The study extends the regime of transverse sur- face waves and may lead to potential applications to surface acoustic wave devices.展开更多
Li-doped ZnO thin films had been grown by radio frequency magnetron sputtering and then annealed under various annealing temperatures. The characteristics of ZnO films were examined by XRD, FESEM, Hall measurement and...Li-doped ZnO thin films had been grown by radio frequency magnetron sputtering and then annealed under various annealing temperatures. The characteristics of ZnO films were examined by XRD, FESEM, Hall measurement and optical transmission spectra. Results showed that p type conduction was observed in Li doped ZnO films annealed at 500-600 ℃ and thep type ZnO films possessed a good crystalline with c-axis orientation, dense surface, and average transmission of about 85% in visible spectral region.展开更多
We describe the fabrication of high performance YBa2Cu3O7-δ （YBCO） radio frequency （RF） superconducting quantum interference devices （SQUIDs）, which were prepared on 5 mm×5 mm LaAlO3 （LAO） substrates by ...We describe the fabrication of high performance YBa2Cu3O7-δ （YBCO） radio frequency （RF） superconducting quantum interference devices （SQUIDs）, which were prepared on 5 mm×5 mm LaAlO3 （LAO） substrates by employing stepedge junctions （SEJs） and in flip-chip configuration with 12 mm×12 mm resonators. The step in the substrate was produced by Ar ion etching with step angles ranging from 47° to 61°, which is steep enough to ensure the formation of grain boundaries （GBs） at the step edges. The YBCO film was deposited using the pulsed laser deposition （PLD） technique with a film thickness half of the height of the substrate step. The inductance of the SQUID washer was designed to be about 157 pH. Under these circumstances, high performance YBCO RF SQUIDs were successfully fabricated with a typical flux-voltage transfer ratio of 83 mV/φ0, a white flux noise of 29 μφ0/√Hz, and the magnetic field sensitivity as high as 80 fT/√Hz. These devices have been applied in magnetocardiography and geological surveys.展开更多
Analog Devices公司最新推出一款模数转换器（ADC）--AD7190,实现了数据速率和无噪声分辨率的最佳组合,使工业设备制造商能够提高精密测量仪器仪表的工作速度和精度。同类竞争器件的分辨率在速度超过1 kHz时会迅速下降,而ADI公司的24-bi...Analog Devices公司最新推出一款模数转换器（ADC）--AD7190,实现了数据速率和无噪声分辨率的最佳组合,使工业设备制造商能够提高精密测量仪器仪表的工作速度和精度。同类竞争器件的分辨率在速度超过1 kHz时会迅速下降,而ADI公司的24-bitAD7190∑-△ADC在40mv-5V的整个输入电压范围内，当速率高达2．4kHz时仍可实现优于真16-bit的无噪声分辨率。展开更多
Analog Devices，Inc．最新推出具有业界最低噪声的宽带宽连续时间∑-△（CTSD）模数转换器（ADC）系列产品——AD926x。16bitAD9261与AD9262CTSD转换器及AD9267CTSD调制器可提供低噪声、高动态范围，以及高达10MHz的带宽。新款ADC系列...Analog Devices，Inc．最新推出具有业界最低噪声的宽带宽连续时间∑-△（CTSD）模数转换器（ADC）系列产品——AD926x。16bitAD9261与AD9262CTSD转换器及AD9267CTSD调制器可提供低噪声、高动态范围，以及高达10MHz的带宽。新款ADC系列产品通过集成突破性的CTSD转换器技术，实现了速度、精度和带宽的独特组合，非常适合于无线基础设施、医疗设备，以及对数据分辨率和宽带宽有严格要求的其它高性能设备。展开更多
Nanoscale two-dimensional(2D)organic materials have attracted significant interest on account of their unique properties,which result from their ultrathin and flat morphology.Supramolecular 2D nanomaterials prepared b...Nanoscale two-dimensional(2D)organic materials have attracted significant interest on account of their unique properties,which result from their ultrathin and flat morphology.Supramolecular 2D nanomaterials prepared by bottom-up approaches have great potential in the creation of nanoscale devices with various applications,each controlled by the properties of its single-molecular components.Here,we report a uniform and controllable 2D rhombic micelles formed by block copolymers(BCPs)with poly(p-phenylenevinylene)(PPV)as core blocks.The supramolecular 2D nanostructures created in this way and driven byπ-πinteractions realize the precise separation of the semiconducting and insulating constituents of the constructed BCPs.With a vertical tunneling device design,the 2D rhombic micelles exhibited an on-off current ratio of>10^(4)and a high on-state current density of 6000 A cm^(−2)as the insulating layer was compressed by a conductive atomic force microscopy(C-AFM)probe.The tunneling device also shows a reproducible sensitivity on a flexible substrate,opening up potential flexible pressure sensor applications for such novel supramolecular 2D nanostructures.展开更多
基金supported by the National Basic Research Program of China(2007CB607506)the Fok Ying-Tong Education Foundation for Young Teachers in the Higher Education Institutions of China(111005)the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(11121202)
文摘This paper presents an analytical solution for the thermoelastic stress in a typical in-plane＇s thin-film micro- thermoelectric cooling device under different operating con- ditions. The distributions of the permissible temperature fields in multilayered thin-films are analytically obtained, and the characteristics, including maximum temperature dif- ference and maximum refrigerating output of the thermo- electric device, are discussed for two operating conditions. Analytical expressions of the thermoelastic stresses in the layered thermoelectric thin-films induced by the tempera- ture difference are formulated based on the theory of mul- tilayer system. The results demonstrate that, the geometric dimension is a significant factor which remarkably affects the thermoelastic stresses. The stress distributions in layers of semiconductor thermoelements, insulating and support- ing membrane show distinctly different features. The present work may profitably guide the optimization design of high- efficiency micro-thermoelectric cooling devices.
基金supported by the National Natural Science Foundation of China(Grant No. 50979113)the High Technology Research and Development Program of China(863 Program,Grant No. 2006AA09A105)
文摘Along with the consumption increase of the petroleum products, more countries have transferred their attentions to the offshore fields, especially the deepwater oil and gas reserves. For deepwater exploitation, the risers must be installed to act as the conduits connecting surface platforms to subsea facilities. In this paper, the typical risers sorted by different classes are introduced, and the correspondent installation methods are presented. By investigating the recent projects performed in the deepwater hot spots, and combining the challenges of HYSY20 l for riser installation, a lifting device developed for assisting riser installation is proposed and detailed to satisfy the installation of deepwater risers in the LW3-1 Gas Field of 1500 m in the South China Sea. Tests on both the functions and performances of such a new system exhibit the satisfaction of meeting all challenging requirements of HYSY201 for application to riser installation in waters up to a depth of 3000 m in the South China Sea.
基金supported by the National Natural Science Foundation of China(10972171)the Program for New Century Excellent Talents in Universities(NCET-08-0429)
文摘The existence and propagation of transverse surface waves in piezoelectric coupled solids is investigated, in which perfect bonding between a metal/dielectric substrate and a piezoelectric layer of finite-thickness is assumed. Dis- persion equations relating phase velocity to material con- stants for the existence of various modes are obtained in a simple mathematical form for a piezoelectric material of class 6mm. It is discovered and proved by numerical examples in this paper that a novel Bleustein-Gulyaev （B-G） type of transverse surface wave can exist in such piezoelectric cou- pled solid media when the bulk-shear-wave velocity in the substrate is less than that in the piezoelectric layer but greater than the corresponding B-G wave velocity in the same pie- zoelectric material with an electroded surface. Such a wave does not exist in such layered structures in the absence of pie- zoelectricity. The mode shapes for displacement and electric potential in the piezoelectric layer are obtained and discussed theoretically. The study extends the regime of transverse sur- face waves and may lead to potential applications to surface acoustic wave devices.
基金Funded by the Natural Science Foundation of Liaoning,China(No.201204916)Training Programme Foundation for the Talents by the Education Bureau of Liaoning Province,China(No.LJQ2013068)+1 种基金Key Program of Ministry of Education,China(No.212031)Liaoning College Creative Team(No.LT2013014)
文摘Li-doped ZnO thin films had been grown by radio frequency magnetron sputtering and then annealed under various annealing temperatures. The characteristics of ZnO films were examined by XRD, FESEM, Hall measurement and optical transmission spectra. Results showed that p type conduction was observed in Li doped ZnO films annealed at 500-600 ℃ and thep type ZnO films possessed a good crystalline with c-axis orientation, dense surface, and average transmission of about 85% in visible spectral region.
基金supported by the National Basic Research Program of China(Grant No.2011CBA00106)the National Natural Science Foundation of China(Grant No.11074008)the Research Fund for the Doctoral Program of Higher Education,China(Grant No.20100001120006)
文摘We describe the fabrication of high performance YBa2Cu3O7-δ （YBCO） radio frequency （RF） superconducting quantum interference devices （SQUIDs）, which were prepared on 5 mm×5 mm LaAlO3 （LAO） substrates by employing stepedge junctions （SEJs） and in flip-chip configuration with 12 mm×12 mm resonators. The step in the substrate was produced by Ar ion etching with step angles ranging from 47° to 61°, which is steep enough to ensure the formation of grain boundaries （GBs） at the step edges. The YBCO film was deposited using the pulsed laser deposition （PLD） technique with a film thickness half of the height of the substrate step. The inductance of the SQUID washer was designed to be about 157 pH. Under these circumstances, high performance YBCO RF SQUIDs were successfully fabricated with a typical flux-voltage transfer ratio of 83 mV/φ0, a white flux noise of 29 μφ0/√Hz, and the magnetic field sensitivity as high as 80 fT/√Hz. These devices have been applied in magnetocardiography and geological surveys.
基金This studywas supported financially by the National Natural Science Foundation of China(nos.21975115,21733005,and 11674150)the Shenzhen Fundamental Research Programs(nos.JCYJ20180302180238419,JCYJ20190809161413310,and KQJSCX20180319114442157)+4 种基金the Shenzhen Nobel Prize Scientists Laboratory Project(no.C17213101)the Guangdong Provincial Key Laboratory of Catalysis(no.2020B121201002)the Key-Area Research and Development Program of Guangdong Province(no.2019B010931001)the Guangdong Innovative and Entrepreneurial Research Team Program(under contract nos.2016ZT06G587 and 2016ZT06D348)the“Shenzhen Sci-Tech Fund”(no.KYTDPT20181011104007).
文摘Nanoscale two-dimensional(2D)organic materials have attracted significant interest on account of their unique properties,which result from their ultrathin and flat morphology.Supramolecular 2D nanomaterials prepared by bottom-up approaches have great potential in the creation of nanoscale devices with various applications,each controlled by the properties of its single-molecular components.Here,we report a uniform and controllable 2D rhombic micelles formed by block copolymers(BCPs)with poly(p-phenylenevinylene)(PPV)as core blocks.The supramolecular 2D nanostructures created in this way and driven byπ-πinteractions realize the precise separation of the semiconducting and insulating constituents of the constructed BCPs.With a vertical tunneling device design,the 2D rhombic micelles exhibited an on-off current ratio of>10^(4)and a high on-state current density of 6000 A cm^(−2)as the insulating layer was compressed by a conductive atomic force microscopy(C-AFM)probe.The tunneling device also shows a reproducible sensitivity on a flexible substrate,opening up potential flexible pressure sensor applications for such novel supramolecular 2D nanostructures.
