Nanodevices using the photovoltaic effect of a single nanowire have attracted growing interest. In this paper, we consider potential applications of the photovoltaic effect to optical signal coupling and optical power...Nanodevices using the photovoltaic effect of a single nanowire have attracted growing interest. In this paper, we consider potential applications of the photovoltaic effect to optical signal coupling and optical power transmission, and report on the realization of a heterojunction formed between WO2 and WO3 in a fine-wire having a diameter on the micrometer scale. Using a laser beam of 514.5 nm as a signal source, the WO2-WO3 heterojunction yields a maximum output power of up to 37.4 pico watt per heterojunction. Fast responses （less than a second） of both photovoltaic voltage and current are also observed. In addition, we demonstrate that it is a simple and effective way to adapt a commercial Raman spectrometer for the combined functions of fabrication, material characterization and photovottaic measurement of an optical signal coupler and optical power transmitter based on a fine-wire. Our results show an attractive perspective of developing nanowire or fine-wire elements for coupling optical signals into and for powering a nanoelectronic or nano-optoelectronic integrated circuit that works under the condition of preventing it from directly electrically connecting with the optical coupler.展开更多
A blinded retrospective validation study was performed in a university-based hospital in northeastern China to determine whether the breast imaging reporting and data system (BI- RADS) defines a group of patients with...A blinded retrospective validation study was performed in a university-based hospital in northeastern China to determine whether the breast imaging reporting and data system (BI- RADS) defines a group of patients with non- palpable breast lesions (NPBLs) in whom fine- wire localization biopsy (FWLB) is appropriate. We reviewed 182 consecutive patients with NPBLs who underwent FWLB. The patients’ preoperative mammograms were categorized according BI-RADS by 2 radiologists blinded to the pathological findings. The positive predictive values of BI-RADS categories 3-5 were 3.4%, 42.1%, and 76.9%, respectively. For category 4 NPBLs, the percentage of cancer for those aged < 40 years was significantly lower than those aged ≥ 40 years. For category 3 NPBLs, the percentage of precancerous lesions for those aged < 40 years was significantly lower than those aged ≥ 40 years. Chinese NPBL patients aged ≥ 40 years with category 4 mammographic findings, and all patients with category 5 findings should undergo FWLB. FWLB should be offered as a treatment option for Chinese NPBL patients aged < 40 years with category 4 findings or aged ≥ 40 years with category 3 findings.展开更多
随着雷达性能指标不断提高、体积不断压缩,作为其关键组成部分成之一的T/R(transmitter and receiver)组件也不断向小型化和高密度方向发展.采用超高密度引线键合技术能够实现高密度射频器件封装,但也会带来键合焊点可靠性下降、电路射...随着雷达性能指标不断提高、体积不断压缩,作为其关键组成部分成之一的T/R(transmitter and receiver)组件也不断向小型化和高密度方向发展.采用超高密度引线键合技术能够实现高密度射频器件封装,但也会带来键合焊点可靠性下降、电路射频性能差等问题.针对键合线尺寸减小而引起射频性能下降的问题,采用HFSS软件探究了在0~20 GHz金带尺寸变化对电路射频性能的影响规律,并利用ANSYS Q3D和ADS软件对超细引线键合的电路进行阻抗匹配.结果表明,对于金丝和金带而言,插入微带双枝短截线匹配结构均能明显提高电路的射频性能.对于类型1结构,S21与S12的传输功率能达到-0.049 dB.对于类型2结构,S21与S12的传输功率能达到-7.245×10-5 dB,说明类型2结构下的信号传输几乎无损耗.该结果为超细引线键合技术在射频电路中的应用提供了理论指导.展开更多
采用 DSC、弯曲实验和扫描电镜分析研究了热处理工艺对医用 TiNi 合金细丝显微组织、相变温度和形状记忆效应的影响。结果表明,400℃~500℃,30 min^120 min 热处理时,随着温度的升高和时间的增长,TiNi 合金细丝中 Ti3Ni4析出相增多,相...采用 DSC、弯曲实验和扫描电镜分析研究了热处理工艺对医用 TiNi 合金细丝显微组织、相变温度和形状记忆效应的影响。结果表明,400℃~500℃,30 min^120 min 热处理时,随着温度的升高和时间的增长,TiNi 合金细丝中 Ti3Ni4析出相增多,相变温度也升高。细丝经 500℃,30 min 处理后的最大可回复应变量值最大。随弯曲变形量的增加,疲劳寿命缩短。500℃处理的试样疲劳寿命最长。展开更多
在电磁工程应用中,天线通过加载,可以缩短天线尺寸,实现小型化设计.文中提出了网格内置集总元件的时域有限差分(Finite Difference Time Domain,FDTD)处理新方法,将细导线FDTD与集总元件FDTD结合起来,模拟了强电磁脉冲对集总加载线天线...在电磁工程应用中,天线通过加载,可以缩短天线尺寸,实现小型化设计.文中提出了网格内置集总元件的时域有限差分(Finite Difference Time Domain,FDTD)处理新方法,将细导线FDTD与集总元件FDTD结合起来,模拟了强电磁脉冲对集总加载线天线的耦合,能够快速计算得到天线上耦合的电流响应.通过与有限积分法软件的仿真结果进行对比,验证了混合算法的正确性.在此基础上,分析了入射电磁脉冲的类型以及脉冲宽度对天线上电流响应的影响,为天线进行前门防护设计提供理论依据.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos. U0634002,50725206 and 50672135)the National Basic Research Program of China (Grant Nos. 2003CB314701,2007CB935501 and 2008AA03A314)the Department of Information Industry of Guangdong Province,China
文摘Nanodevices using the photovoltaic effect of a single nanowire have attracted growing interest. In this paper, we consider potential applications of the photovoltaic effect to optical signal coupling and optical power transmission, and report on the realization of a heterojunction formed between WO2 and WO3 in a fine-wire having a diameter on the micrometer scale. Using a laser beam of 514.5 nm as a signal source, the WO2-WO3 heterojunction yields a maximum output power of up to 37.4 pico watt per heterojunction. Fast responses （less than a second） of both photovoltaic voltage and current are also observed. In addition, we demonstrate that it is a simple and effective way to adapt a commercial Raman spectrometer for the combined functions of fabrication, material characterization and photovottaic measurement of an optical signal coupler and optical power transmitter based on a fine-wire. Our results show an attractive perspective of developing nanowire or fine-wire elements for coupling optical signals into and for powering a nanoelectronic or nano-optoelectronic integrated circuit that works under the condition of preventing it from directly electrically connecting with the optical coupler.
文摘A blinded retrospective validation study was performed in a university-based hospital in northeastern China to determine whether the breast imaging reporting and data system (BI- RADS) defines a group of patients with non- palpable breast lesions (NPBLs) in whom fine- wire localization biopsy (FWLB) is appropriate. We reviewed 182 consecutive patients with NPBLs who underwent FWLB. The patients’ preoperative mammograms were categorized according BI-RADS by 2 radiologists blinded to the pathological findings. The positive predictive values of BI-RADS categories 3-5 were 3.4%, 42.1%, and 76.9%, respectively. For category 4 NPBLs, the percentage of cancer for those aged < 40 years was significantly lower than those aged ≥ 40 years. For category 3 NPBLs, the percentage of precancerous lesions for those aged < 40 years was significantly lower than those aged ≥ 40 years. Chinese NPBL patients aged ≥ 40 years with category 4 mammographic findings, and all patients with category 5 findings should undergo FWLB. FWLB should be offered as a treatment option for Chinese NPBL patients aged < 40 years with category 4 findings or aged ≥ 40 years with category 3 findings.
文摘采用 DSC、弯曲实验和扫描电镜分析研究了热处理工艺对医用 TiNi 合金细丝显微组织、相变温度和形状记忆效应的影响。结果表明,400℃~500℃,30 min^120 min 热处理时,随着温度的升高和时间的增长,TiNi 合金细丝中 Ti3Ni4析出相增多,相变温度也升高。细丝经 500℃,30 min 处理后的最大可回复应变量值最大。随弯曲变形量的增加,疲劳寿命缩短。500℃处理的试样疲劳寿命最长。
文摘在电磁工程应用中,天线通过加载,可以缩短天线尺寸,实现小型化设计.文中提出了网格内置集总元件的时域有限差分(Finite Difference Time Domain,FDTD)处理新方法,将细导线FDTD与集总元件FDTD结合起来,模拟了强电磁脉冲对集总加载线天线的耦合,能够快速计算得到天线上耦合的电流响应.通过与有限积分法软件的仿真结果进行对比,验证了混合算法的正确性.在此基础上,分析了入射电磁脉冲的类型以及脉冲宽度对天线上电流响应的影响,为天线进行前门防护设计提供理论依据.
