91 research outputs found
Integration of InP and InGaAs on 300 mm Si wafers using chemical mechanical planarization
Integration of III-V high mobility channel materials in complementary metal oxide semiconductors (CMOS) and III-V photonic materials for integrated light sources on Si substrates requires low defect density III-V buffer layers in order to enable epitaxial growth of high crystal quality active layers. For the fabrication of In0.53Ga0.47As n-channel MOSFET on Si, a lattice matched InP buffer layer is one of the most effective approaches when used in combination with the aspect ratio trapping technique, an integration method known for reducing the density of defects formed during relaxation of strain induced by the lattice mismatch between InP and Si. The InP buffer should be planarized in order to improve thickness uniformity and roughness before subsequent deposition of active layers. In this work we discuss the development of InP planarization on 300 mm Si wafers and investigate slurry composition effects on the final oxide loss and condition of the InP surface. To further explore viability of this approach we deposited an epitaxial In0.53Ga0.47As n-MOS channel layer on top of the planarized InP buffer
Nontarget emotional stimuli must be highly conspicuous to modulate the attentional blink
The attentional blink (AB) is often considered a top-down phenomenon because it is triggered by matching an initial target (T1) in a rapid serial visual presentation (RSVP) stream to a search template. However, the AB is modulated when targets are emotional, and is evoked when a task-irrelevant, emotional critical distractor (CDI) replaces T1. Neither manipulation fully captures the interplay between bottom-up and top-down attention in the AB: Valenced targets intrinsically conflate top-down and bottom-up attention. The CDI approach cannotmanipulate second target (T2) valence, which is critical because valenced T2s can âbreak throughâ the AB (in the target-manipulation approach). The present research resolves this methodological challenge by indirectly measuring whether a purely bottom-up CDI can modulate report of a subsequent T2. This novel approach adds a valenced CDI to the âclassic,â two-target AB. Participants viewed RSVP streams containing a T1âCDI pair preceding a variable lag to T2. If the CDIâs valence is sufficient to survive the AB, it should modulate T2 performance, indirectly signaling bottom-up capture by an emotional stimulus. Contrary to this prediction, CDI valence only affected the AB when CDIs were also extremely visually conspicuous. Thus, emotional valence alone is insufficient to modulate the AB
Transcoding Kant: Kracauer's Weimar Marxism and after
This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ Koninklijke Brill NV, Leiden, 2013.Kracauerâs rehabilitation in the 1990s sidelined his Marxist framework of the middle-to-late Weimar era in favour of the then still dominant if decaying paradigms of poststructuralism and postmodernism. It was also silent on the relationship between Kant and Marxism in Kracauerâs work. This essay addresses these weaknesses by arguing that Kracauer transcoded the structure of Kantâs âproblematicâ around reification into a Marxist framework in the middle-to-late Weimar period. The essay considers how Kracauer conceived the mass ornament (photography and film especially) as a site of reification and critical pedagogy. It explores his strategies of de-reification and their overlap with Walter Benjamin and the ruptures and continuities between the radical Weimar work and his later Theory of Film. The essay argues that the Theory of Film can be better understood as a transcoding of Kantâs philosophy of the aesthetic in the third Critique into the film camera itself, although the Marxian framework of the Weimar period is now considerably attenuated
The Effects of Accentuated Eccentric Loading on Barbell and Trap Bar Countermovement Jumps
This study examined effects of accentuated eccentric loading (AEL) on barbell and trap bar loaded countermovement jumps (LCMJ). Twenty-one subjects (16 male, 5 female; Age: 23.5 ± 1.8 years; Body mass: 81.4 ± 10.6 kg; Height: 176.9 ± 7.2 cm; Training age: 7.1 ± 2.6 years) participated in this study. Upon establishing one repetition maximum and baseline jumping conditions, three experimental loading sessions were completed in random order. Barbell and trap bar LCMJ were performed with a spectrum of fixed loads from 20-50 kg during control conditions and with additional AEL loads of 10, 20, or 30 kg for experimental conditions. According to coefficients of variation
Antimicrobial resistance patterns of phenotype Extended Spectrum Beta-Lactamase producing bacterial isolates in a referral hospital in northern Tanzania
Background: Production of Extended Spectrum Beta-Lactamase (ESBL) by bacteria is a chronic problem in a health care set up. In order to have adequate information for treatment of bacterial infections especially ESBL producing isolates, it is crucial to understand the trends in the antibiotic-resistance pattern, occurrence and their geographical spread. The objective of this study was to determine the antimicrobial resistance pattern among phenotype ESBL producing isolates in northern Tanzania.Methods: From July 2013 to January 2014, urine, pus and blood samples were collected from patients suspected to have bacterial infections at Kilimanjaro Christian Medical Centre in Moshi, Tanzania. The isolates were identified based on standard laboratory procedures. Antimicrobial susceptibility tests were carried out using various antimicrobial discs as per the recommendations of Clinical Laboratory Standard Institute.Results: A total of 330 specimens were collected. They consisted of 46 urine, 264 pus (from wound) and 20 blood samples. Among isolated bacteria, ESBL producers were 29.7% (98) and non-producers were 70.5% (232). Escherichia coli and Klebsiella pneumoniae were the most isolated bacteria and dominant ESBL producers. ESBL production was highly associated with moderate condition at discharge and longer periods of admission. More than 60% of the ESBL producing E. coli were resistant to ceftazidime, cefpodoxime, cefotaxime, amoxycilin, ciprofloxacin, and gentamycin. More than 80% of ESBL producing K. pneumonia and Proteus mirabilis were resistant to ceftazidime and cefotaxime. Fifty four percent of ESBL producing K. pneumonia were resistant to gentamycin.Conclusion: This study shows that ESLB phenotypes among Gram-negative bacteria are common among patients attending a tertiary hospital in northern in Tanzania. The findings suggest that clinical microbiology laboratories should take into account the diagnosis of ESBL producers in order to define the degree of the problem so as to establish a proper treatment protocol
Nanoscale imaging of He-ion irradiation effects on amorphous TaO toward electroforming-free neuromorphic functions
Resistive switching in thin films has been widely studied in a broad range of
materials. Yet the mechanisms behind electroresistive switching have been
persistently difficult to decipher and control, in part due to their
non-equilibrium nature. Here, we demonstrate new experimental approaches that
can probe resistive switching phenomena, utilizing amorphous TaO as a model
material system. Specifically, we apply Scanning Microwave Impedance Microscopy
(sMIM) and cathodoluminescence (CL) microscopy as direct probes of conductance
and electronic structure, respectively. These methods provide direct evidence
of the electronic state of TaO despite its amorphous nature. For example CL
identifies characteristic impurity levels in TaO, in agreement with first
principles calculations. We applied these methods to investigate He-ion-beam
irradiation as a path to activate conductivity of materials and enable
electroforming-free control over resistive switching. However, we find that
even though He-ions begin to modify the nature of bonds even at the lowest
doses, the films conductive properties exhibit remarkable stability with large
displacement damage and they are driven to metallic states only at the limit of
structural decomposition. Finally, we show that electroforming in a nanoscale
junction can be carried out with a dissipated power of < 20 nW, a much smaller
value compared to earlier studies and one that minimizes irreversible
structural modifications of the films. The multimodal approach described here
provides a new framework toward the theory/experiment guided design and
optimization of electroresistive materials
Cation-eutectic transition via sublattice melting in CuInP2S6/In4/3P2S6 van der Waals layered crystals
Single crystals of the van der Waals layered ferrielectric material CuInP2S6 spontaneously phase separate when synthesized with Cu deficiency. Here we identify a route to form and tune intralayer heterostructures between the corresponding ferrielectric (CuInP2S6) and paraelectric (In4/3P2S6) phases through control of chemical phase separation. We conclusively demonstrate that Cu-deficient Cu1âxIn1+x/3P2S6 forms a single phase at high temperature. We also identify the mechanism by which the phase separation proceeds upon cooling. Above 500 K both Cu+ and In3+ become mobile, while P2S64â anions maintain their structure. We therefore propose that this transition can be understood as eutectic melting on the cation sublattice. Such a model suggests that the transition temperature for the melting process is relatively low because it requires only a partial reorganization of the crystal lattice. As a result, varying the cooling rate through the phase transition controls the lateral extent of chemical domains over several decades in size. At the fastest cooling rate, the dimensional confinement of the ferrielectric CuInP2S6 phase to nanoscale dimensions suppresses ferrielectric ordering due to the intrinsic ferroelectric size effect. Intralayer heterostructures can be formed, destroyed, and re-formed by thermal cycling, thus enabling the possibility of finely tuned ferroic structures that can potentially be optimized for specific device architectures
EMG Biofeedback Videogame System for the Gait Rehabilitation of Hemiparetic Individuals
Gemstone Team CHIPWe report a novel approach to electromyographic (EMG) biofeedback for post-stroke hemiparetic gait rehabilitation, using a videogame. An integrated hardware/software system facilitates gameplay of Tiger Woods PGA Tour 2004 in driving range mode by performing rehabilitation exercises. Real-time visual EMG biofeedback is provided as the patient performs exercises. Custom-built bioamplifiers and software collect, amplify, and filter the surface EMG signals from six lower-limb muscles, and score them by feature extraction. The ball is driven a distance proportional to each score. Exercises are scored by comparing the patient's EMG activation with target profiles. The user-friendly system is controlled by prompts on a personal computer. We envision two major benefits from this system. First, the biofeedback is offered in real-time, in a clear, intuitive form, and coupled with task-specific motions. Second, we hypothesize that adopting rehabilitation exercises to control a fun videogame will lead to greater adherence to the exercise regime, with accompanying improvements in gait
Enhanced electric conductivity at ferroelectric vortex cores in BiFeO3
In many large ensembles, the property of the system as a whole cannot be understood from studying the individual entities alone Âż these ensembles can be made up by neurons in the brain, transport users in traffic networks or data packages in the Internet. The past decade has seen important progress in our fundamental understanding of what such seemingly disparate 'complex systems' have in common; some of these advances are surveyed here
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