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21.
Transport mechanism of reverse surface leakage current in AlGaN/GaN high-electron mobility transistor with SiN passivation 下载免费PDF全文
The transport mechanism of reverse surface leakage current in the AlGaN/GaN high-electron mobility transistor(HEMT) becomes one of the most important reliability issues with the downscaling of feature size.In this paper,the research results show that the reverse surface leakage current in AlGaN/GaN HEMT with SiN passivation increases with the enhancement of temperature in the range from 298 K to 423 K.Three possible transport mechanisms are proposed and examined to explain the generation of reverse surface leakage current.By comparing the experimental data with the numerical transport models,it is found that neither Fowler-Nordheim tunneling nor Frenkel-Poole emission can describe the transport of reverse surface leakage current.However,good agreement is found between the experimental data and the two-dimensional variable range hopping(2D-VRH) model.Therefore,it is concluded that the reverse surface leakage current is dominated by the electron hopping through the surface states at the barrier layer.Moreover,the activation energy of surface leakage current is extracted,which is around 0.083 eV.Finally,the SiN passivated HEMT with a high Al composition and a thin AlGaN barrier layer is also studied.It is observed that 2D-VRH still dominates the reverse surface leakage current and the activation energy is around 0.10 eV,which demonstrates that the alteration of the AlGaN barrier layer does not affect the transport mechanism of reverse surface leakage current in this paper. 相似文献
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传统的Zernike多项式在光机优化设计中存在着一定的局限性,如离散情况下正交性损失仅适用于与圆同胚的边界光滑平面单连通区域。利用Laplace方程得到的特征模态所具有的离散正交性和共形性质,在有限元数值离散的情况下,实现对光学曲面变形的近似表述,并对圆形光学反射镜支撑结构进行以特征基底系数极小为目标的结构拓扑优化。将特征模态的优化结果与Zernike多项式优化结果对比之后发现,特征模态可以取得和Zernike多项式近似的优化性能。在此基础上,进一步将特征模态应用于六边形曲面镜支撑结构的拓扑优化。 相似文献
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大家知道,一切元素除惰性气体以外的原子,都可以包含在分子的成分中。把原子结合在分子内的力的本性可用量子力学来解释。对于分子的形成起决定作用的是交换相互作用。这种相互作用表现在原子的价电子易位,出现公共的电子云,它使一个原子结連在另一个的周围。 相似文献
25.
Reverse blocking enhancement of drain field plate in Schottky-drain AlGaN/GaN high-electron mobility transistors 下载免费PDF全文
In this paper, we present the combination of drain field plate(FP) and Schottky drain to improve the reverse blocking capability, and investigate the reverse blocking enhancement of drain FP in Schottky-drain AlGaN/GaN high-electron mobility transistors(HEMTs). Drain FP and gate FP were employed in a two-dimensional simulation to improve the reverse blocking voltage(VRB) and the forward blocking voltage(VFB). The drain-FP length, the gate-FP length and the passivation layer thickness were optimized. VRBand VFBwere improved from-67 V and 134 V to-653 V and 868 V respectively after optimization. Simulation results suggest that the combination of drain FP and Schottky drain can enhance the reverse blocking capability significantly. 相似文献
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频率标定是瑞利测风激光雷达的关键技术。瑞利测风激光雷达中,通过改变压电陶瓷管的电压实现连续调谐F-P标准具腔长,使出射激光频率处于双边缘透过率曲线的交点处。在连续调谐时,由于压电陶瓷管的磁滞效应引起腔长调谐非线性,从而导致系统误差。分析了该误差的原因及特性,提出了静态软件补偿和动态调频跟踪相结合的频率标定方法。若激光出射频率相对F-P标准具漂移小于100 MHz时,在数据反演时补偿该频率偏差;若相对频率漂移大于100 MHz时,将F-P标准具先退回预设腔长以下,通过逐步增加电压的方式,重新实现频率锁定,保证锁定过程处在磁滞回线的电压上升段,避免了磁滞效应引起的误差。多普勒激光雷达与无线电探空仪的两组对比实验中,在15~30 km高度,风速最大偏差6.22 m/s,平均偏差1.12 m/s。 相似文献
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Novel CMOS image sensor pixel to improve charge transfer speed and efficiency by overlapping gate and temporary storage diffusing node 下载免费PDF全文
A novel CMOS image sensor(CIS) pinned photodiode(PPD) pixel, named as O-T pixel, is proposed and investigated by TCAD simulations. Compared with the conventional PPD pixel, the proposed pixel features the overlapping gate(OG)and the temporary storage diffusing(TSD) region, based on which the several-nanosecond-level charge transfer could be achieved and the complete charge transfer from the PPD to the floating node(FD) could be realized. And systematic analyses of the influence of the doping conditions of the proposed processes, the OG length, and the photodiode length on the transfer performances of the proposed pixel are conducted. Optimized simulation results show that the total charge transfer time could reach about 5.862 ns from the photodiode to the sensed node and the corresponding charge transfer efficiency could reach as high as 99.995% in the proposed pixel with 10 μm long photodiode and 2.22 μm long OG. These results demonstrate a great potential of the proposed pixel in high-speed applications. 相似文献
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本文通过沉积在多孔硅表面的银纳米粒吸附对氨基苯硫酚和氨基的化学转化得到终端为NiⅡ-Nα,Nα-二(羧甲基)-L-赖氨酸水合物-即 NiⅡ-NTA体系的芯片。NiⅡ-NTA修饰的芯片被用于从高浓度的盐和助溶剂的缓冲体系中亲和捕获组氨酸标记的融合蛋白:thioredoxin-urodilatin和SUMO-hu-aprotinin,并进行在线的MALDI-TOF质谱检测,克服了MALDI-TOF质谱中直接点样污染物妨碍样品与基质共结晶的问题,避免了繁琐的离线样品预处理。芯片在线分离、纯化和MALDI-TOF质谱分析体系有望在复杂或原始体液的溶液中分析目标分子。 相似文献