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排序方式: 共有6236条查询结果,搜索用时 15 毫秒
61.
Yaou Smets Christian B. Stark Felix Schmitt Mark T. Edmonds Stefan Lach Christopher A. Wright Daniel P. Langley Kevin J. Rietwyk Alex Schenk Anton Tadich Martina Wanke Christiane Ziegler Lothar Ley Christopher I. Pakes 《Organic Electronics》2013,14(1):169-174
High resolution synchrotron-based core level spectroscopy was used to examine the energy level alignment at the interface of zinc–tetraphenylporphyrin films doped by the surface acceptor C60F48. Two distinct fluorofullerene charge states were identified, corresponding to ionized and neutral molecules, and their relative concentration as a function of coverage was used to evaluate the probability of occupation of the acceptor lowest unoccupied molecular orbital (LUMO). From an initial acceptor energy of ?0.25 eV, the C60F48 LUMO shifts upwards with coverage due to a doping-induced interfacial dipole potential, and stabilization of the LUMO at an energy 0.45 eV above the Fermi energy was obtained. While the energy difference upon saturation is consistent with the results obtained for other donor–acceptor systems that have been interpreted as Fermi level pinning, the present work shows that the energy offset is a direct consequence of the interplay between Fermi–Dirac statistics in combination with the interfacial dipole potential. 相似文献
62.
中国联通“世界风”的双模手机业务也推出一段日子了。CDMA/GSM左右逢源本是一件普天同庆的事,但由于机型的匮乏,业务尚末完善,使得双模手机一直给人雷声大雨点小的感觉。但这并未影响联通进行双模推广的步伐,一些最新的双模手机都在陆续的推出,各大厂商也是年初陆续发布了旗下最新的产品。本次《数码》率先拿到了两款最新的双模手机,分别是由宇龙通信公司出品的酷派(CoolPad)858和三星公司最新推出的W19。我们将会在下面的内容里作最详尽的评测。 相似文献
63.
This letter is a supplement of the table of the minimal cost one-dimensional linear hybrid cellular automata with the maximum length cycle by Zhang, Miller, and Muzio [IEE Electronics Letters, 27(18):1625–1627, August 1991].This work was supported in part by Research Grants and Postgraduate Scholarships from the Natural Sciences and Engineering Research Council of Canada and by an equipment loan from the Canadian Microelectronics Corporation. 相似文献
64.
Abdullah H. Alshehri Kissan Mistry Viet Huong Nguyen Khaled H. Ibrahim David Muoz‐Rojas Mustafa Yavuz Kevin P. Musselman 《Advanced functional materials》2019,29(7)
A quantum‐tunneling metal‐insulator‐metal (MIM) diode is fabricated by atmospheric pressure chemical vapor deposition (AP‐CVD) for the first time. This scalable method is used to produce MIM diodes with high‐quality, pinhole‐free Al2O3 films more rapidly than by conventional vacuum‐based approaches. This work demonstrates that clean room fabrication is not a prerequisite for quantum‐enabled devices. In fact, the MIM diodes fabricated by AP‐CVD show a lower effective barrier height (2.20 eV) at the electrode–insulator interface than those fabricated by conventional plasma‐enhanced atomic layer deposition (2.80 eV), resulting in a lower turn on voltage of 1.4 V, lower zero‐bias resistance, and better asymmetry of 107. 相似文献
65.
Ida Sadeghi Kevin Ye Michael Xu Yifei Li James M. LeBeau Rafael Jaramillo 《Advanced functional materials》2021,31(45):2105563
The making of BaZrS3 thin films by molecular beam epitaxy (MBE) is demonstrated. BaZrS3 forms in the orthorhombic distorted-perovskite structure with corner-sharing ZrS6 octahedra. The single-step MBE process results in films smooth on the atomic scale, with near-perfect BaZrS3 stoichiometry and an atomically sharp interface with the LaAlO3 substrate. The films grow epitaxially via two competing growth modes: buffered epitaxy, with a self-assembled interface layer that relieves the epitaxial strain, and direct epitaxy, with rotated-cube-on-cube growth that accommodates the large lattice constant mismatch between the oxide and the sulfide perovskites. This work sets the stage for developing chalcogenide perovskites as a family of semiconductor alloys with properties that can be tuned with strain and composition in high-quality epitaxial thin films, as has been long-established for other systems including Si-Ge, III-Vs, and II-VIs. The methods demonstrated here also represent a revival of gas-source chalcogenide MBE. 相似文献
66.
Kevin Kattmann 《电子产品世界》2005,(21):168-169
数据转换器有意义的衡量方法是什么?就数据转换器自身而言,它是相当容易定义的.数据转换器是通过模数转换器(ADC)将连续的电信号(即模拟信号)转换为数码字[以比特(bit)为单位]或反过来,通过数模转换器(DAC)将数码字转换为连续的模拟信号.这样的转换过程是我们周围的真实世界和我们用以监测、分析、控制的计算机世界之间的至关重要的连接.其中最困难和有发展意义的问题是如何为这些数据转换器定义重要的性能指标. 相似文献
67.
Pukar Malla Hasnain Lakdawala Ravi Naiknaware Krishnamurthy Soumyanath Kevin Kornegay 《Analog Integrated Circuits and Signal Processing》2010,65(2):197-208
Modern multi-standard receivers in deep-submicron technologies pose significant design challenges on the analog baseband.
Moving this analog filtering to the digital domain simplifies the design, yielding a process-scalable implementation. However,
analog-to-digital converter (ADC) specifications now become more stringent and must be obtained by comprehending the standard
and the system. Assuming a receiver NF of 5.96 dB and SNR degradation of 0.36 dB by the ADC, the proposed dual-mode WiFi/WiMAX
receiver attains an input sensitivity of −74 dBm (20 MHz channel bandwidth). To accommodate the high dynamic range and the
anti-alias rejection needed for the system, a Delta-Sigma (ΔΣ) ADC is proposed. Single-loop and Multi-Stage Noise-Shaping
(MASH) architectures that achieve a SNR of 69 dB at a low oversampling ratio (OSR) of 8 for a conversion bandwidth of 40 MHz
(108 Mbps, OFDM) are investigated at system level. Based on thermal noise, harmonic distortion, and power tradeoffs, a ΔΣ
ADC design that meets the design specifications is presented. 相似文献
68.
Barbu A Suehling M Xu X Liu D Zhou SK Comaniciu D 《IEEE transactions on medical imaging》2012,31(2):240-250
Lymph nodes are assessed routinely in clinical practice and their size is followed throughout radiation or chemotherapy to monitor the effectiveness of cancer treatment. This paper presents a robust learning-based method for automatic detection and segmentation of solid lymph nodes from CT data, with the following contributions. First, it presents a learning based approach to solid lymph node detection that relies on marginal space learning to achieve great speedup with virtually no loss in accuracy. Second, it presents a computationally efficient segmentation method for solid lymph nodes (LN). Third, it introduces two new sets of features that are effective for LN detection, one that self-aligns to high gradients and another set obtained from the segmentation result. The method is evaluated for axillary LN detection on 131 volumes containing 371 LN, yielding a 83.0% detection rate with 1.0 false positive per volume. It is further evaluated for pelvic and abdominal LN detection on 54 volumes containing 569 LN, yielding a 80.0% detection rate with 3.2 false positives per volume. The running time is 5-20 s per volume for axillary areas and 15-40 s for pelvic. An added benefit of the method is the capability to detect and segment conglomerated lymph nodes. 相似文献
69.
70.
Ackermann DM Smith B Wang XF Kilgore KL Peckham PH 《IEEE transactions on bio-medical engineering》2008,55(4):1365-1373
Optical telemetry has long been an option for transcutaneous data transfer and has been used in various types of implanted systems. This telemetry modality and the efficiency of these optical links are becoming ever more important as higher bandwidth sources such as cortical recording arrays are being implemented in implanted systems. The design of the transmitter-skin-receiver interface (the "optical interface") is paramount to the operation of a transcutaneous optical telemetry link. This interface functions to achieve sufficient receiver signal power for data communication. This paper describes a mathematical analysis and supporting data that quantitatively describes the relationship between the primary interface design parameters. These parameters include the thickness of the skin through which the light is transmitted, the size of the integration area of the optics, the degree of transmitter-receiver misalignment, the efficiency of the optics system, and the emitter power. The particular combination of these parameters chosen for the hardware device will determine the receiver signal power and, therefore, the data quality for the link. This paper demonstrates some of the tradeoffs involved in the selection of these design parameters and provides suggestions for link design. This analysis may also be useful for transcutaneous optical powering systems. 相似文献