Electronic shutter control for planetary photography with automatic time recording capability

Electromechanical shutter system for planetary photography using semiconductor electronics and automatic time recordin

Proceedings of the Cold Electronics Workshop

The benefits and problems of the use of cold semiconductor electronics and the research and development effort required to bring cold electronics into more widespread use were examined

Innovation and venture capital exit performance

Venture capital is a potent source of R&D financing which contributes significantly to technological innovation output in the form of patented inventions. Scholars have argued that tighter protection of intellectual property rights reduces expropriation risks and encourages venture capitalists to invest in technology firms. Prior studies have showed that early stage technology investors give much weight to investment selection criteria related to innovation e.g. protection of intellectual property, platform and uniqueness. However, VC investors generally receive little on their investments until a liquidation event occurs – IPO and M&A (trade sale) exits define venture capital performance. A review of the literature indicates that few empirical studies have examined the influence of patented innovation on the exit performance of VC-backed technology firms. This paper seeks to address this specific knowledge gap in venture capital research and practice. It builds on resource-based view (RBV) theory which argues that technological innovation is an important strategic resource of the entrepreneurial firm that can attract VC investment, provide competitive advantage and produce superior performance. This study is based on matched data compiled from VentureXpertTM, DelphionTM and NBER/USPTO databases. The resulting unique and proprietary dataset consists of 1504 U.S. VC-backed exits across 7 technology sectors in the 20 years from 1980-2000, 961 IPOs and 543 M&As. The influence of technological innovation on the exit performance of VC-backed technology firms is examined. As predicted by RBV theory, technology firms engaged in patenting activity were found more likely to be associated with the more profitable IPO exit route, higher VC investment and exit value

Zipping and unzipping of nanoscale carbon structures

We demonstrate theoretically that hydrogenation and annealing applied to nanoscale carbon structures play a crucial role in determining the final shape of the system. In particular, graphene flakes characterized by the linear and non-hydrogenated zigzag or armchair edges have high propensity to merge into a bigger flake or a nanotube (the formation of a single carbon-carbon bond lowers the total energy of the system by up to 6.22 eV). Conversely, the line of the $sp^2$ carbon bonds (common for pure carbon structures such as graphene or a carbon nanotube) converted into the $sp^3$ type by hydrogenation shows an ability to disassemble the original structure by cutting it along the line of the modified bonds. These structural transformations provide us with an understanding of the behavior of mobile carbon structures in solution and a distinct scenario of how to preserve the original structure which would be a crucial issue for their application in carbon-based electronics.Comment: 7 pages, 6 figure

Chemical patterning for the highly specific and programmed assembly of nanostructures

We have developed a new chemical patterning technique based on standard lithography-based processes to assemble nanostructures on surfaces with extraordinarily high selectivity. This patterning process is used to create patterns of aminosilane molecular layers surrounded by highly inert poly (ethylene glycol) (PEG) molecules. While the aminosilane regions facilitate nanostructure assembly, the PEG coating prevents adsorption of molecules and nanostructures, thereby priming the semiconductor substrate for the highly localized and programmed assembly of nanostructures. We demonstrate the power and versatility of this manufacturing process by building multilayered structures of gold nanoparticles attached to molecules of DNA onto the aminosilane patterns, with zero nanocrystal adsorption onto the surrounding PEG regions. The highly specific surface chemistry developed here can be used in conjunction with standard microfabrication and emerging nanofabrication technology to seamlessly integrate various nanostructures with semiconductor electronics

Silicon Spintronics

Integration of magnetism and mainstream semiconductor electronics could impact information technology in ways beyond imagination. A pivotal step is implementation of spin-based electronic functionality in silicon devices. Remarkable progress made during the last two years gives confidence that this is within reach, although significant challenges also remain

Oriented Graphene Nanoribbons Embedded in Hexagonal Boron Nitride Trenches

Graphene nanoribbons (GNRs) are ultra-narrow strips of graphene that have the potential to be used in high-performance graphene-based semiconductor electronics. However, controlled growth of GNRs on dielectric substrates remains a challenge. Here, we report the successful growth of GNRs directly on hexagonal boron nitride substrates with smooth edges and controllable widths using chemical vapour deposition. The approach is based on a type of template growth that allows for the in-plane epitaxy of mono-layered GNRs in nano-trenches on hexagonal boron nitride with edges following a zigzag direction. The embedded GNR channels show excellent electronic properties, even at room temperature. Such in-plane hetero-integration of GNRs, which is compatible with integrated circuit processing, creates a gapped channel with a width of a few benzene rings, enabling the development of digital integrated circuitry based on GNRs.Comment: 32 pages, 4 figures, Supplementary informatio

Structural equation modelling and system dynamic in the detection of power quality events

The issues of power quality had been discussed since the starting of power system and it will keep on arise from time to time because power quality is important to electricity consumers at all levels of usage. Since sensitive equipments and power electronic devices are now more common in industrial/commercial sectors as well as domestic use, the awareness of power quality is developing amongst electricity users. In general, the main power quality issues can be identified as voltage variations, voltage imbalance, voltage fluctuations, transients, harmonic distortions, interruptions, etc. The consequences of one or more of the above non-ideal conditions may cause thermal effects, life expectancy reduction, dielectric strength reduction and disoperation of different equipments. In this project, power quality events are verified using Structural Equation Modeling (SEM) and System Dynamic method. In detecting power quality events, Amos 5.0.1 and Vensim PLE for Windows version 5.11 were used. The verification of power quality events involves identification, classification and mitigation process on several power quality events that occurred in electrical power system

Deterioration rate of renewable polyurethanes composites prior to ultra violet irradiation exposure

Polyurethanes (PU's) made from renewable and sustainable materials are one of the most important groups of polymers because of their versatility with wide range of grades, densities and stiffness. In this project, polymers based on renewable materials such as rapeseed (RS) and sunflower oil (SF) were synthesized and cross-linked to form polyurethanes. The effect of prolonged exposure up to 1000 h upon UVB light, in general promotes photodegradation for both RS and SF-based polyurethanes, both neat and also composites loaded with TiO2. The addition of 10% Degussa P25 TiO2 pigment, gives the greater degradation while PUs loaded with 5% Kronos 2220 show the slowest rates of degradation due to the effect of the coating of this pigment. The photostabiliser Tinuvin 770 offers high protection from UVB, thus lead the combination of Tinuvin 770 with Degussa P25 promotes the highest protection from UVB exposure. Moreover, addition of Tinuvin 770 at the stage of preparation of the PUs also greatly reduced the undesirable yellow colouration prevalent during PU synthesis

Heterostructure unipolar spin transistors

We extend the analogy between charge-based bipolar semiconductor electronics and spin-based unipolar electronics by considering unipolar spin transistors with different equilibrium spin splittings in the emitter, base, and collector. The current of base majority spin electrons to the collector limits the performance of ``homojunction'' unipolar spin transistors, in which the emitter, base, and collector all are made from the same magnetic material. This current is very similar in origin to the current of base majority carriers to the emitter in homojunction bipolar junction transistors. The current in bipolar junction transistors can be reduced or nearly eliminated through the use of a wide band gap emitter. We find that the choice of a collector material with a larger equilibrium spin splitting than the base will similarly improve the device performance of a unipolar spin transistor. We also find that a graded variation in the base spin splitting introduces an effective drift field that accelerates minority carriers through the base towards the collector.Comment: 9 pages, 2 figure