Quantum Computer Development with Single Ion Implantation

Spins of single donor atoms are attractive candidates for large scale quantum information processing in silicon. Formation of devices with a few qubits is crucial for validation of basic ideas and development of a scalable architecture. We describe our development of a single ion implantation technique for placement of single atoms into device structures. Collimated highly charged ion beams are aligned with a scanning probe microscope. Enhanced secondary electron emission due tohigh ion charge states (e.g., ³¹P¹³⁺, or ¹²⁶Te³³⁺)allows efficient detection of single ion impacts. Studies of electrical activation of low dose, low energy implants of ³¹P in silicon show a drastic effect of dopant segregation to the SiO₂/Si interface,while Si₃N₄/Si retards ³¹P segregation. We discuss resolution limiting factors in ion placement, and process challenges forintegration of single atom arrays with control gates and single electron transistors. PACS: 03.67.Lx, 34.50.Dy, 85.35.Gv, 73.23, 61.72, 86.40.py, 07.79.-v     

Noise peaks influence communication in the operating room. An observational study

Noise peaks are powerful distractors. This study focuses on the impact of noise peaks on surgical teams’ communication during 109 long abdominal surgeries. We related measured noise peaks during 5-min intervals to the amount of observed communication during the same interval. Results show that noise peaks are associated with less case-relevant communication; this effect is moderated by the level of surgical experience; case-relevant communications decrease under high noise peak conditions among junior, but not among senior surgeons. However, case-irrelevant communication did not decrease under high noise level conditions, rather there was a trend to more case-irrelevant communication under high noise peaks. The results support the hypothesis that noise peaks impair communication because they draw on attentional resources rather than impairing understanding of communication. As case-relevant communication is important for surgical performance, exposure to high noise peaks in the OR should be minimised especially for less experienced surgeons.

Practitioner Summary: This study investigated whether noise during surgeries influenced the communication within surgical teams. During abdominal surgeries, noise levels were measured and communication was observed. Results showed that high noise peaks reduced the frequency of patient-related communication, but did not reduce patient-irrelevant communication. Noise may negatively affect team coordination in surgeries.     

Structural Analysis of Mitochondrial Dynamics—From Cardiomyocytes to Osteoblasts: A Critical Review

Mitochondria play a crucial role in cell physiology and pathophysiology. In this context, mitochondrial dynamics and, subsequently, mitochondrial ultrastructure have increasingly become hot topics in modern research, with a focus on mitochondrial fission and fusion. Thus, the dynamics of mitochondria in several diseases have been intensively investigated, especially with a view to developing new promising treatment options. However, the majority of recent studies are performed in highly energy-dependent tissues, such as cardiac, hepatic, and neuronal tissues. In contrast, publications on mitochondrial dynamics from the orthopedic or trauma fields are quite rare, even if there are common cellular mechanisms in cardiovascular and bone tissue, especially regarding bone infection. The present report summarizes the spectrum of mitochondrial alterations in the cardiovascular system and compares it to the state of knowledge in the musculoskeletal system. The present paper summarizes recent knowledge regarding mitochondrial dynamics and gives a short, but not exhaustive, overview of its regulation via fission and fusion. Furthermore, the article highlights hypoxia and its accompanying increased mitochondrial fission as a possible link between cardiac ischemia and inflammatory diseases of the bone, such as osteomyelitis. This opens new innovative perspectives not only for the understanding of cellular pathomechanisms in osteomyelitis but also for potential new treatment options.     

2.1 A/mm current density AlGaN/GaN HEMT

The electrical performance of high current density AlGaN/GaN HEMTs is reported. 2 /spl times/ 75 /spl mu/m /spl times/ 0.7 /spl mu/m devices grown on sapphire substrates showed current densities up to 2.1 A/mm under 200 ns pulse condition. RF power measurements at 8 GHz and V/sub DS/=15 V exhibited a saturated output power of 3.66 W/mm with a 47.8% peak PAE.     

芯片尺寸是否越大越好?

把更多的功能和更多的门电路集成在一块芯片上的能力——无论你将这块芯片称为SoC(单片系统)、ASIC(专用集成电路)还是称为一块大型集成电路——正在迅速提高。在亚微米设计和亚微米制造工艺的推动下,以及在更好的EDA工具和程序库的支持下,人们可以把数百万个子电路集成在一块硅片上。这种情况也许会有人认为,一种定制的、一块集成电路的体系结构——或许还能得到几个新奇而又     

3G基站的两个关键部件--高速数据转换器和放大器

第三代移动电话主要依靠宽带码分多址(WCDMA)技术,信号处理技术的发展、体系结构的进步以及新开发的高速数据转换器和运算放大器正在使无线基础结构的设计师们降低成本,更好地实现第三代无线通信系统的目标。     

Effect of ohmic contacts on buffer leakage of GaN transistors

The effect of ohmic contacts on the buffer leakage of GaN transistors is presented. The buffer leakage for AlGaN/GaN high-electron mobility transistors and GaN MESFETs grown on the same underlying buffer was observed to be different. Controlled experiments show that the increased buffer leakage is due to the nature of the alloyed ohmic contacts and can be minimized if they are screened by the Si doping or by the two-dimensional electron gas.     

Wireless capsule endoscopy video segmentation using an unsupervised learning approach based on probabilistic latent semantic analysis with scale invariant features

Since wireless capsule endoscopy (WCE) is a novel technology for recording the videos of the digestive tract of a patient, the problem of segmenting the WCE video of the digestive tract into subvideos corresponding to the entrance, stomach, small intestine, and large intestine regions is not well addressed in the literature. A selected few papers addressing this problem follow supervised leaning approaches that presume availability of a large database of correctly labeled training samples. Considering the difficulties in procuring sizable WCE training data sets needed for achieving high classification accuracy, we introduce in this paper an unsupervised learning approach that employs Scale Invariant Feature Transform (SIFT) for extraction of local image features and the probabilistic latent semantic analysis (pLSA) model used in the linguistic content analysis for data clustering. Results of experimentation indicate that this method compares well in classification accuracy with the state-of-the-art supervised classification approaches to WCE video segmentation.     

Novel algorithm for time division multiple access in broadband ISDN passive optical networks

For shared access to a broadband communication network using the asynchronous transfer mode (ATM) a passive optical network (PON) has previously been proposed. A novel algorithm to evaluate the time division multiple access (TDMA) protocol which controls the traffic from the various subscribers towards the shared access equipment (upstream direction) is proposed. It uses counters to estimate the moment of a data packet arrival at the subscriber side. By this ‘look-ahead’ technique no extra upstream channels are needed to initiate the polling by the subscriber. The algorithm guarantees fair access for all subscribers and minimizes the necessary overhead. Both the maximum access delay and overhead may be readily calculated, and the obtained results were supported by numerical simulation. Applicability in the standard broadband network environment has been proved by hardware design simulation.