A design procedure for a slotted waveguide with probe-fed slots radiating into plasma

International Nuclear Information System (INIS)

Colborn, J.A.

1989-11-01

A design procedure is developed for slotted-waveguide antennas with probe-fed slots. Radiation into a gyrotropic, plane-stratified medium is considered, nonzero waveguide wall thickness is assumed, and noncosinusoidal slot fields and arbitrary slot length up to about one free-space wavelength are allowed. External mutual coupling is taken into account by matching the tangential fields at the antenna surface. The particular case of longitudinal slots in the broad face of rectangular guide is analyzed. The motivation for this work is the design of such radiators for plasma heating and current-drive on thermonuclear fusion experiments, but some of the analysis is applicable to the probeless slotted waveguide used for avionics and communications. 20 refs., 5 figs

Design and Fabrication of Slotted Multimode Interference Devices for Chemical and Biological Sensing

Directory of Open Access Journals (Sweden)

M. Mayeh

2009-01-01

Full Text Available We present optical sensors based on slotted multimode interference waveguides. The sensor can be tuned to highest sensitivity in the refractive index ranges necessary to detect protein-based molecules or other water-soluble chemical or biological materials. The material of choice is low-loss silicon oxynitride (SiON which is highly stable to the reactivity with biological agents and processing chemicals. Sensors made with this technology are suited to high volume manufacturing.

Theoretical examination of the slot channel waveguide configured in a cylindrically symmetric dielectric ring profile

Science.gov (United States)

Gauthier, Robert C.; Alzahrani, Mohammed A.; Jafari, Seyed Hamed

2014-10-01

It has recently been experimentally demonstrated that slot channel waveguides, configured in cylindrical space, can support high azimuthal order modes similar to whispering-gallery modes. This paper presents a mode solver based on Maxwell's vector wave equation for the electric field cast into an eigenvalue problem using a Fourier-Bessel basis function space. The modal frequencies and field profiles of the high azimuthal order slot-channel-whispering-gallery (SCWG) modes are computed for a set of nanometer spaced silicon rings supported by oxide. The computations show, that in addition to the traditionally observed, lowest order mode, the structure may support higher order SCWG modes. We complete the analysis by computing structures response as an ambient medium index of refraction sensor which achieves over 400 nm per RIU sensitivity.

Interaction of Light with Metallized Ultrathin Silicon Membrane

Science.gov (United States)

Shome, Krishanu

Freestanding metallized structures, a few tens of nanometer thick, show promise in creating flow-through sensors, single molecule detectors and novel solar cells. In this thesis we study test structures that are a step towards creating such devices. Finite- difference time-domain simulations have been used to understand and predict the interaction of light with such devices. Porous nanocrystalline silicon membrane is a novel freestanding layer structure that has been used as a platform to fabricate and study sensors and novel slot nanohole devices. Optical mode studies of the sensing structures, together with the method of fabrication inspired the creation of ultrathin freestanding hydrogenated amorphous silicon p-i-n junctions solar cells. All the freestanding structures used in this thesis are just a few tens of nanometers in thicknesses. In the first part of the thesis the sensing properties of the metallized porous nanocrystalline structure are studied. The surprising blueshift associated with the sensing peak is observed experimentally and predicted theoretically with the help of simulations. Polarization dependence of the membranes is predicted and confirmed for angled deposition of metal on the membranes. In the next part, a novel slot structure is fabricated and modeled to study the slot effect in nanohole metal-insulator-metal structures. Atomic layer deposition of alumina is used to conformally deposit alumina within the nanohole to create the slot structure. Simulation models were used to calculate the lowest modal volume of 4x10-5 mum3 for an optimized structure. In the last part of the thesis, freestanding solar cells are fabricated by effectively replacing the porous nanocrystalline silicon layer of the membranes with a hydrogenated amorphous silicon p-i-n junction with metal layers on both sides of the p-i-n junction. The metal layers act both as electrical contacts as well as mirrors for a Fabry Perot cavity resonator. This helps in tuning the

A Photonic 1 × 4 Power Splitter Based on Multimode Interference in Silicon–Gallium-Nitride Slot Waveguide Structures

Directory of Open Access Journals (Sweden)

Dror Malka

2016-06-01

Full Text Available In this paper, a design for a 1 × 4 optical power splitter based on the multimode interference (MMI coupler in a silicon (Si–gallium nitride (GaN slot waveguide structure is presented—to our knowledge, for the first time. Si and GaN were found as suitable materials for the slot waveguide structure. Numerical optimizations were carried out on the device parameters using the full vectorial-beam propagation method (FV-BPM. Simulation results show that the proposed device can be useful to divide optical signal energy uniformly in the C-band range (1530–1565 nm into four output ports with low insertion losses (0.07 dB.

A Photonic 1 × 4 Power Splitter Based on Multimode Interference in Silicon–Gallium-Nitride Slot Waveguide Structures

Science.gov (United States)

Malka, Dror; Danan, Yossef; Ramon, Yehonatan; Zalevsky, Zeev

2016-01-01

In this paper, a design for a 1 × 4 optical power splitter based on the multimode interference (MMI) coupler in a silicon (Si)–gallium nitride (GaN) slot waveguide structure is presented—to our knowledge, for the first time. Si and GaN were found as suitable materials for the slot waveguide structure. Numerical optimizations were carried out on the device parameters using the full vectorial-beam propagation method (FV-BPM). Simulation results show that the proposed device can be useful to divide optical signal energy uniformly in the C-band range (1530–1565 nm) into four output ports with low insertion losses (0.07 dB). PMID:28773638

Slot-coupled CW standing wave accelerating cavity

Energy Technology Data Exchange (ETDEWEB)

Wang, Shaoheng; Rimmer, Robert; Wang, Haipeng

2017-05-16

A slot-coupled CW standing wave multi-cell accelerating cavity. To achieve high efficiency graded beta acceleration, each cell in the multi-cell cavity may include different cell lengths. Alternatively, to achieve high efficiency with acceleration for particles with beta equal to 1, each cell in the multi-cell cavity may include the same cell design. Coupling between the cells is achieved with a plurality of axially aligned kidney-shaped slots on the wall between cells. The slot-coupling method makes the design very compact. The shape of the cell, including the slots and the cone, are optimized to maximize the power efficiency and minimize the peak power density on the surface. The slots are non-resonant, thereby enabling shorter slots and less power loss.

Coupling slots without shunt impedance drop

International Nuclear Information System (INIS)

Balleyguier, P.

1996-01-01

It is well known that coupling slots between adjacent cells in a π-mode structure reduce shunt impedance per unit length with respect to single cell cavities. To design optimized coupling slots, one has to answer the following question: for a given coupling factor, what shape, dimension, position and number of slots lead to the lowest shunt impedance drop? A numerical study using the 3D code MAFIA has been carried out. The aim was to design the 352 MHz cavities for the high intensity proton accelerator of the TRISPAL project. The result is an unexpected set of four 'petal' slots. Such slots should lead to a quasi-negligible drop in shunt impedance: about -1% on average, for particle velocity from 0.4 c to 0.8 c. (author)

Slot-Coupled Barbel Antenna

DEFF Research Database (Denmark)

Jørgensen, Kasper Lüthje; Jakobsen, Kaj Bjarne

2016-01-01

A novel slot-coupled barbel antenna is designed and analyzed. A sensitivity analysis performed in order to improve the bandwidth, while the center frequency is kept constant.......A novel slot-coupled barbel antenna is designed and analyzed. A sensitivity analysis performed in order to improve the bandwidth, while the center frequency is kept constant....

G-Tunnel pressurized slot-testing preparations

International Nuclear Information System (INIS)

Zimmerman, R.M.; Sifre-Soto, C.; Mann, K.L.; Bellman, R.A. Jr.; Luker, S.; Dodds, D.J.

1992-04-01

Designers and analysts of radioactive waste repositories must be able to predict the mechanical behavior of the host rock. Sandia National laboratories elected to conduct a development program on pressurized slot testing and featured (1) development of an improved method to cut slots using a chain saw with diamond-tipped cutters, (2) measurements useful for determining in situ stresses normal to slots, (3) measurements applicable for determining the in situ modulus of deformation parallel to a drift surface, and (4) evaluations of the potentials of pressurized slot strength testing. This report describes the preparations leading to the measurements and evaluations

Optical Slot-Waveguide Based Biochemical Sensors

Directory of Open Access Journals (Sweden)

Carlos Angulo Barrios

2009-06-01

Full Text Available Slot-waveguides allow light to be guided and strongly confined inside a nanometer-scale region of low refractive index. Thus stronger light-analyte interaction can be obtained as compared to that achievable by a conventional waveguide, in which the propagating beam is confined to the high-refractive-index core of the waveguide. In addition, slot-waveguides can be fabricated by employing CMOS compatible materials and technology, enabling miniaturization, integration with electronic, photonic and fluidic components in a chip, and mass production. These advantages have made the use of slot-waveguides for highly sensitive biochemical optical integrated sensors an emerging field. In this paper, recent achievements in slot-waveguide based biochemical sensing will be reviewed. These include slot-waveguide ring resonator based refractometric label-free biosensors, label-based optical sensing, and nano-opto-mechanical sensors.

MHD-flow in slotted channels with conducting walls

International Nuclear Information System (INIS)

Evtushenko, I.A.; Kirillov, I.R.; Reed, C.B.

1994-07-01

A review of experimental results is presented for magnetohydrodynamic (MHD) flow in rectangular channels with conducting walls and high aspect ratios (longer side parallel to the applied magnetic field), which are called slotted channels. The slotted channel concept was conceived at Efremov Institute as a method for reducing MHD pressure drop in liquid metal cooled blanket design. The experiments conducted by the authors were aimed at studying both fully developed MHD-flow, and the effect of a magnetic field on the hydrodynamics of 3-D flows in slotted channels. Tests were carried out on five models of the slotted geometry. A good agreement between test and theoretical results for the pressure drop in slotted channels was demonstrated. Application of a open-quotes one-electrode movable probeclose quotes for velocity measurement permitted measurement of the M-shape velocity profiles in the slotted channels. Suppression of 3-D inertial effects in slotted channels of complex geometry was demonstrated based on potential distribution data

Pumping slots: impedances and power losses

Energy Technology Data Exchange (ETDEWEB)

Kurennoy, S [Maryland Univ., College Park, MD (United States). Dept. of Physics

1996-08-01

Contributions of pumping slots to the beam coupling impedances and power losses in a B-factory ring are considered. While their leading contribution is to the inductive impedance, for high-intensity machines with short bunches like e{sup +}e{sup -} B-factories the real part of the impedance and related loss factors are also important. Using an analytical approach we calculate the coupling impedances and loss factors due to slots in a ring with an arbitrary cross section of the vacuum chamber. Effects of the slot tilt on the beam impedance are also considered, and restrictions on the tilt angle are derived from limitations on the impedance increase. The power leakage through the slots is discussed briefly. The results are applied to the KEK B-factory. (author)

Strengthening of oxidation resistant materials for gas turbine applications. [treatment of silicon ceramics for increased flexural strength and impact resistance

Science.gov (United States)

Kirchner, H. P.

1974-01-01

Silicon nitride and silicon carbide ceramics were treated to form compressive surface layers. On the silicon carbide, quenching and thermal exposure treatments were used, and on the silicon nitride, quenching, carburizing, and a combination of quenching and carburizing were used. In some cases substantial improvements in impact resistance and/or flexural strength were observed. The presence of compressive surface stresses was demonstrated by slotted rod tests.

Student-Led Objective Tutorial (SLOT) in Medical Education.

Science.gov (United States)

Sivagnanam, Gurusamy; Saraswathi, Simansalam; Rajasekaran, Aiyalu

2006-12-01

Purpose - To assess an innovative tutoring program named 'Student-Led Objective Tutorial' (SLOT) among undergraduate medical students. Method - The program was conceptualized by the Pharmacology Unit of Faculty of Medicine and Health Sciences, Asian Institute of Medicine Science & Technology (AIMST), Malaysia and implemented in the middle of 2005. A cohort of 246 medical undergraduate students (spread across 5 consecutive batches) participated. Following a brief explanation on the purpose and nature of SLOT, each batch was divided into small groups and was given a reading assignment on 4 previously delivered lecture topics. Each group was asked to prepare 3-5 multiple choice questions (MCQs) of their own in PowerPoint format to be presented, in turns, to the whole class on the day of SLOT. The proceedings were facilitated by 2 lecturers. Student feedback on the efficacy and benefits were assessed through an anonymous self administered questionnaire. Results - About 76% (188) of the students favored SLOT. The acceptance rate of SLOT was higher among males. There was no significant difference between batches in their opinions on whether to pursue SLOT in future. The most prevalent positive comment was that SLOT enhanced learning skills, and the negative comment being, it consumed more time. Conclusions - SLOT is a novel tutorial method which can offset faculty shortage with advantages like enhanced interest among teachers and learners, uniform reach of content, opportunities for group learning, and involvement of visual aids as teaching-learning (T-L) method. SLOT unraveled the students' potential of peer tutoring both inside as well as outside the classroom. Consumer tutors (students) can be tapped as a resource for SLOT for all subjects and courses in healthcare teaching.

Slotting allowances to coordinate manufacturers’ retail sales effort

OpenAIRE

Foros, Øystein; Kind, Hans Jarle; Sand, Jan Yngve

2007-01-01

Slotting allowances are fees paid by manufacturers to get access to retailers’ shelf space. Although the main attention towards slotting allowances has been within the grocery industry, slotting allowances have also been applied within e.g. e-commerce and mobile telephony. In these industries we observe that distributors have large market power due to their control of access to customers. We analyse how shifting bargaining power from manufacturers to retailers and the use of slotting allowanc...

Stereoscopic display in a slot machine

Science.gov (United States)

Laakso, M.

2012-03-01

This paper reports the results of a user trial with a slot machine equipped with a stereoscopic display. The main research question was to find out what kind of added value does stereoscopic 3D (S-3D) bring to slot games? After a thorough literature survey, a novel gaming platform was designed and implemented. Existing multi-game slot machine "Nova" was converted to "3DNova" by replacing the monitor with an S-3D display and converting six original games to S-3D format. To evaluate the system, several 3DNova machines were put available for players for four months. Both qualitative and quantitative analysis was carried out from statistical values, questionnaires and observations. According to the results, people find the S-3D concept interesting but the technology is not optimal yet. Young adults and adults were fascinated by the system, older people were more cautious. Especially the need to wear stereoscopic glasses provide a challenge; ultimate system would probably use autostereoscopic technology. Also the games should be designed to utilize its full power. The main contributions of this paper are lessons learned from creating an S-3D slot machine platform and novel information about human factors related to stereoscopic slot machine gaming.

Dual Mode Slotted Monopole Antenna

Science.gov (United States)

2017-01-05

May 2017 The below identified patent application is available for licensing. Requests for information should be addressed to: TECHNOLOGY...REFERENCE TO OTHER PATENT APPLICATIONS [0002] None. BACKGROUND OF THE INVENTION (1) Field of the Invention [0003] The present invention is directed...to connect across slot 14. [0005] In United States Patent No. 6,127,983 to Rivera and Josypenko, it has been shown that the slotted cylinder

S-parameters for weakly excited slots

DEFF Research Database (Denmark)

Albertsen, Niels Christian

1999-01-01

A simple approach to account for parasitic effects in weakly excited slots cut in the broad wall of a rectangular waveguide is proposed......A simple approach to account for parasitic effects in weakly excited slots cut in the broad wall of a rectangular waveguide is proposed...

Slot Machine Response Frequency Predicts Pathological Gambling

DEFF Research Database (Denmark)

Linnet, Jakob; Rømer Thomsen, Kristine; Møller, Arne

2013-01-01

Slot machines are among the most addictive forms of gambling, and pathological gambling slot machine players represent the largest group of treatment seekers, accounting for 35% to 93% of the population. Pathological gambling sufferers have significantly higher response frequency (games / time......) on slot machines compared with non-problem gamblers, which may suggest increased reinforcement of the gambling behavior in pathological gambling. However, to date it is unknown whether or not the increased response frequency in pathological gambling is associated with symptom severity of the disorder....... This study tested the hypothesis that response frequency is associated with symptom severity in pathological gambling. We tested response frequency among twenty-two pathological gambling sufferers and twenty-one non-problem gamblers on a commercially available slot machine, and screened for pathological...

Silicon-based horizontal nanoplasmonic slot waveguides for on-chip integration.

Science.gov (United States)

Zhu, Shiyang; Liow, T Y; Lo, G Q; Kwong, D L

2011-04-25

Horizontal metal/insulator/Si/insulator/metal nanoplasmonic slot waveguide (PWG), which is inserted in a conventional Si wire waveguide, is fabricated using the standard Si-CMOS technology. A thin insulator between the metal and the Si core plays a key role: it not only increases the propagation distance as the theoretical prediction, but also prevents metal diffusion and/or metal-Si reaction. Cu-PWGs with the Si core width of ~134-21 nm and ~12-nm-thick SiO2 on each side exhibit a relatively low propagation loss of ~0.37-0.63 dB/µm around the telecommunication wavelength of 1550 nm, which is ~2.6 times smaller than the Al-counterparts. A simple tapered coupler can provide an effective coupling between the PWG and the conventional Si wire waveguide. The coupling efficiency as high as ~0.1-0.4 dB per facet is measured. The PWG allows a sharp bending. The pure bending loss of a Cu-PWG direct 90° bend is measured to be ~0.6-1.0 dB. These results indicate the potential for seamless integration of various functional nanoplasmonic devices in existing Si electronic photonic integrated circuits (Si-EPICs).

Slotted Circularly Polarized Microstrip Antenna for RFID Application

Directory of Open Access Journals (Sweden)

S. Kumar

2017-12-01

Full Text Available A single layer coaxial fed rectangular microstrip slotted antenna for circular polarization (CP is proposed for radio frequency identification (RFID application. Two triangular shaped slots and one rectangular slot along the diagonal axis of a square patch have been embedded. Due to slotted structure along the diagonal axis and less surface area, good quality of circular polarization has been obtained with the reduction in the size of microstrip antenna by 4.04 %. Circular polarization radiation performance has been studied by size and angle variation of diagonally slotted structures. The experimental result found for 10-dB return loss is 44 MHz with 10MHz of 3dB Axial Ratio (AR bandwidth respectively at the resonant frequency 910 MHz. The overall proposed antenna size including the ground plane is 80 mm x 80 mm x 4.572 mm.

Influence of Closed Stator Slots on Cogging Torque

DEFF Research Database (Denmark)

Ion, Trifu; Leban, Krisztina Monika; Ritchie, Ewen

2013-01-01

Cogging torque results due interaction of magnetic field of magnets and stator slots, and have negative effects on permanent magnet machines such as vibrations, noise, torque ripples and problems during turbine start-up and cut-in. In order to reduce cogging torque this paper presents a study...... of influence of closed stator slots on cogging torque using magnetic slot wedges....

Slot Antenna for Wireless Temperature Measurement Systems

DEFF Research Database (Denmark)

Acar, Öncel; Jakobsen, Kaj Bjarne

2016-01-01

This paper presents a novel clover-slot antenna for a surface-acoustic-wave sensor based wireless temperature measurement system. The slot is described by a parametric locus curve that has the shape of a clover. The antenna is operated at high temperatures, in rough environments, and has a 43......% fractional bandwidth at the 2.4 GHz ISM-band. The slot antenna has been optimized for excitation by a passive chip soldered onto it. Measurement results are compared with simulation results and show good agreements....

Vertically Polarized Omnidirectional Printed Slot Loop Antenna

DEFF Research Database (Denmark)

Kammersgaard, Nikolaj Peter Iversen; Kvist, Søren H.; Thaysen, Jesper

2015-01-01

A novel vertically polarized omnidirectional printed slot loop antenna has been designed, simulated, fabricated and measured. The slot loop works as a magnetic loop. The loop is loaded with inductors to insure uniform and in-phase fields in the slot in order to obtain an omnidirectional radiation...... pattern. The antenna is designed for the 2.45 GHz Industrial, Scientific and Medical band. Applications of the antenna are many. One is for on-body applications since it is ideal for launching a creeping waves due to the polarization....

G-tunnel pressurized slot-testing evaluations

International Nuclear Information System (INIS)

Zimmerman, R.M.; Sifre-Soto, C.; Mann, K.L.; Bellman, R.A. Jr.; Luker, S.; Dodds, D.J.

1992-04-01

Designers and analysts of radioactive waste repositories must be able to predict the mechanical behavior of the host rock. Sandia National Laboratories elected to conduct a development program to enhance mechanical-type measurements. The program was focused on pressurized slot testing and featured (1) development of an improved method to cut slots using a chain saw with diamond-tipped cutters, (2) measurements useful for determining in situ stresses normal to slots, (3) measurements applicable for determining the in situ modulus of deformation parallel to a drift surface, and (4) evaluations of pressurized slot strength testing results and methods. This report contains data interpretation and evaluations. Included are recommendations for future efforts. This third report contains the interpretations of the testing with emphasis on the measurement results as they apply to describing rock behavior. In particular, emphases are placed on (1) normal stress determinations using the flatjack cancellation (FC) method, (2) modulus of deformation determinations, and (3) high pressure investigations. Most of the material in the first two reports is not repeated here. Appropriate data are repeated in tabular form

Energy dissipation of slot-type flip buckets

Science.gov (United States)

Wu, Jian-hua; Li, Shu-fang; Ma, Fei

2018-03-01

The energy dissipation is a key index in the evaluation of energy dissipation elements. In the present work, a flip bucket with a slot, called the slot-type flip bucket, is theoretically and experimentally investigated by the method of estimating the energy dissipation. The theoretical analysis shows that, in order to have the energy dissipation, it is necessary to determine the sequent flow depth h 1 and the flow speed V 1 at the corresponding position through the flow depth h 2 after the hydraulic jump. The relative flow depth h 2 / h 。 is a function of the approach flow Froude number Fr 。, the relative slot width b/B 。, and the relative slot angle θ/β. The expression for estimating the energy dissipation is developed, and the maximum error is not larger than 9.21%.

49 CFR 236.809 - Signal, slotted mechanical.

Science.gov (United States)

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Signal, slotted mechanical. 236.809 Section 236.809 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... § 236.809 Signal, slotted mechanical. A mechanically operated signal with an electromagnetic device...

A Waveguide Transverse Broad Wall Slot Radiating Between Baffles

DEFF Research Database (Denmark)

Dich, Mikael; Rengarajan, S.R.

1997-01-01

An analysis of the self impedance of waveguide-fed transverse slots radiating between baffles is presented. The region exterior to the slot is treated as a parallel plate (PP) waveguide which radiates into half space through an aperture in an infinite ground plane. The slot problem is analyzed...

Double-Slot Hybrid Plasmonic Ring Resonator Used for Optical Sensors and Modulators

Directory of Open Access Journals (Sweden)

Xu Sun

2015-11-01

Full Text Available An ultra-high sensitivity double-slot hybrid plasmonic (DSHP ring resonator, used for optical sensors and modulators, is developed. Due to high index contrast, as well as plasmonic enhancement, a considerable part of the optical energy is concentrated in the narrow slots between Si and plasmonic materials (silver is used in this paper, which leads to high sensitivity to the infiltrating materials. By partial opening of the outer plasmonic circular sheet of the DSHP ring, a conventional side-coupled silicon on insulator (SOI bus waveguide can be used. Experimental results demonstrate ultra-high sensitivity (687.5 nm/RIU of the developed DSHP ring resonator, which is about five-times higher than for the conventional Si ring with the same geometry. Further discussions show that a very low detection limit (5.37 × 10−6 RIU can be achieved after loaded Q factor modifications. In addition, the plasmonic metal structures offer also the way to process optical and electronic signals along the same hybrid plasmonic circuits with small capacitance (~0.275 fF and large electric field, which leads to possible applications in compact high-efficiency electro-optic modulators, where no extra electrodes for electronic signals are required.

Slot Optimization Design of Induction Motor for Electric Vehicle

Science.gov (United States)

Shen, Yiming; Zhu, Changqing; Wang, Xiuhe

2018-01-01

Slot design of induction motor has a great influence on its performance. The RMxprt module based on magnetic circuit method can be used to analyze the influence of rotor slot type on motor characteristics and optimize slot parameters. In this paper, the authors take an induction motor of electric vehicle for a typical example. The first step of the design is to optimize the rotor slot by RMxprt, and then compare the main performance of the motor before and after the optimization through Ansoft Maxwell 2D. After that, the combination of optimum slot type and the optimum parameters are obtained. The results show that the power factor and the starting torque of the optimized motor have been improved significantly. Furthermore, the electric vehicle works at a better running status after the optimization.

Predictors of return rate discrimination in slot machine play.

Science.gov (United States)

Coates, Ewan; Blaszczynski, Alex

2014-09-01

The purpose of this study was to investigate the extent to which accurate estimates of payback percentages and volatility combined with prior learning, enabled players to successfully discriminate between multi-line/multi-credit slot machines that provided differing rates of reinforcement. The aim was to determine if the capacity to discriminate structural characteristics of gaming machines influenced player choices in selecting 'favourite' slot machines. Slot machine gambling history, gambling beliefs and knowledge, impulsivity, illusions of control, and problem solving style were assessed in a sample of 48 first year undergraduate psychology students. Participants were subsequently exposed to a choice paradigm where they could freely select to play either of two concurrently presented PC-simulated slot machines programmed to randomly differ in expected player return rates (payback percentage) and win frequency (volatility). Results suggest that prior learning and cognitions (particularly gambler's fallacy) but not payback, were major contributors to the ability of a player to discriminate volatility between slot machines. Participants displayed a general tendency to discriminate payback, but counter-intuitively placed more bets on the slot machine with lower payback percentage rates.

The Role of Auditory Features Within Slot-Themed Social Casino Games and Online Slot Machine Games.

Science.gov (United States)

Bramley, Stephanie; Gainsbury, Sally M

2015-12-01

Over the last few years playing social casino games has become a popular entertainment activity. Social casino games are offered via social media platforms and mobile apps and resemble gambling activities. However, social casino games are not classified as gambling as they can be played for free, outcomes may not be determined by chance, and players receive no monetary payouts. Social casino games appear to be somewhat similar to online gambling activities in terms of their visual and auditory features, but to date little research has investigated the cross over between these games. This study examines the auditory features of slot-themed social casino games and online slot machine games using a case study design. An example of each game type was played on three separate occasions during which, the auditory features (i.e., music, speech, sound effects, and the absence of sound) within the games were logged. The online slot-themed game was played in demo mode. This is the first study to provide a qualitative account of the role of auditory features within a slot-themed social casino game and an online slot machine game. Our results found many similarities between how sound is utilised within the two games. Therefore the sounds within these games may serve functions including: setting the scene for gaming, creating an image, demarcating space, interacting with visual features, prompting players to act, communicating achievements to players, providing reinforcement, heightening player emotions and the gaming experience. As a result this may reduce the ability of players to make a clear distinction between these two activities, which may facilitate migration between games.

[Influence of slot size on torque control].

Science.gov (United States)

Tian, Jun; Liu, Zhong-Hao; Zhang, Ding; Wu, Chuan-Jun

2009-12-01

To study the influence of two slot size brackets on torque control when teeth interacted in the same arch. After the upper arch was aligned and leveled in Typodont study, the inclinations of upper teeth 5 +/- 5 were measured when 0.457 2 mm x 0.635 0 mm OPA-K brackets and 0.558 8 mmx0.711 2 mm OPA-K brackets were filled with 0.431 8 mm x 0.635 0 mm stainless steel wire. This experiment was duplicated 10 times. The inclin of each tooth were transformed to the absolute values of the torque play angle psi by computing program, and paired-t test was used. The two kinds of slot size brackets were different with statistical significance on torque control. When the brackets were filled with 0.431 8 mm x 0.635 0 mm stainless steel wire, the absolute values of the angle psi in 0.558 8 mm x 0.711 2 mm and 0.457 2 mm x 0.635 0 mm slot size brackets were 6.140 degrees +/- 3.758 degrees and 2.608 degrees +/- 1.479 degrees respectively, and the average difference of that between the two slot size brackets was 3.532 degrees. The absolute values of the angle psi in the upper left and right canine brackets were 2.560 degrees +/- 2.605 degrees, 4.230 degrees +/- 2.817 degrees, 1.260 degrees +/- 0.747 degrees and 2.070 degrees +/- 0.663 degrees respectively, and average differences between them were smaller than that in the other teeth. There was difference between the two kinds of slot size brackets on torque control, and 0.457 2 mm x 0.635 0 mm slot size bracket controls torque better when filled with the same size wire. In this study, the teeth interaction in the same arch probably caused the result that the difference of two slot size brackets on torque control was less than the study results of the theory calculations and material studys before.

The Gambling Reducing Slot Machine

DEFF Research Database (Denmark)

Callesen, Mette Buhl; Thomsen, Kristine Rømer; Linnet, Jakob

2007-01-01

  The Gambling Reducing Slot Machine - Preliminary results Mette Buhl Callesen, Kristine Rømer Thomsen, Jakob Linnet and Arne Møller The PET Centre, Aarhus University Hospital and Centre of Functionally Integrative Neuroscience, Aarhus, Denmark   Slot machines are among the most addictive forms...... and willingness to continue gambling. The results may have important implications for understanding how to reduce gambling behavior in pathological gamblers.   [1] Griffiths, M. 1999. Gambling Technologies: Prospects for Problem Gambling. Journal of Gambling Studies, vol. 15(3), pp. 265-283.    ...

Theory of a Traveling Wave Feed for a Planar Slot Array Antenna

Science.gov (United States)

Rengarajan, Sembiam

2012-01-01

Planar arrays of waveguide-fed slots have been employed in many radar and remote sensing applications. Such arrays are designed in the standing wave configuration because of high efficiency. Traveling wave arrays can produce greater bandwidth at the expense of efficiency due to power loss in the load or loads. Traveling wave planar slot arrays may be designed with a long feed waveguide consisting of centered-inclined coupling slots. The feed waveguide is terminated in a matched load, and the element spacing in the feed waveguide is chosen to produce a beam squinted from the broadside. The traveling wave planar slot array consists of a long feed waveguide containing resonant-centered inclined coupling slots in the broad wall, coupling power into an array of stacked radiating waveguides orthogonal to it. The radiating waveguides consist of longitudinal offset radiating slots in a standing wave configuration. For the traveling wave feed of a planar slot array, one has to design the tilt angle and length of each coupling slot such that the amplitude and phase of excitation of each radiating waveguide are close to the desired values. The coupling slot spacing is chosen for an appropriate beam squint. Scattering matrix parameters of resonant coupling slots are used in the design process to produce appropriate excitations of radiating waveguides with constraints placed only on amplitudes. Since the radiating slots in each radiating waveguide are designed to produce a certain total admittance, the scattering (S) matrix of each coupling slot is reduced to a 2x2 matrix. Elements of each 2x2 S-matrix and the amount of coupling into the corresponding radiating waveguide are expressed in terms of the element S11. S matrices are converted into transmission (T) matrices, and the T matrices are multiplied to cascade the coupling slots and waveguide sections, starting from the load end and proceeding towards the source. While the use of non-resonant coupling slots may provide an

Radiation from a Slot System in the Coaxial Line Shield

Science.gov (United States)

Katrich, V. A.; Lyashchenko, V. A.; Medvedev, N. V.

2012-06-01

The problem of electromagnetic wave excitation, scattering and radiation by the system of transverse slots, cut in the outer conductor of an infinite coaxial line, is solved by the magnetomotive forces method. The radiation and reflection coefficients of the circular and arc slot systems are investigated in dependence on slot sizes and feeder parameters. The processes of radiation into lossy material media are studied. The researches have been carried out with the interconnection between slots of internal and external regions considered.

Investigation of a slot nanoantenna in optical frequency range

Science.gov (United States)

Dinesh kumar, V.; Asakawa, Kiyoshi

2009-11-01

Following the analogy of radio frequency slot antenna and its complementary dipole, we propose the implementation of a slot nanoantenna (SNA) in the optical frequency range. Using finite-difference time-domain (FDTD) method, we investigate the electromagnetic (EM) properties of a SNA formed in a thin gold film and compare the results with the properties of a gold dipole nanoantenna (DNA) of the same dimension as the slot. It is found that the response of the SNA is very similar to the DNA, like their counterparts in the radio frequency (RF) range. The SNA can enhance the near field intensity of incident field which strongly depends on its feedgap dimension. The resonance of the SNA is influenced by its slot length; for the increasing slot length, resonant frequency decreases whereas the sharpness of resonance increases. Besides, the resonance of the SNA is found sensitive to the thickness of metal film, when the latter is smaller than the skin depth. The effect of polarization of incident field on the EM response of the SNA was examined; the field enhancement is optimum when polarization is parallel to the feedgap. Finally, we calculate the radiation patterns of the DNA and SNA and compare them with those of the RF dipole antenna. The radiation pattern of the SNA is found to be independent of its slot length when excited at resonant frequency. To the best of our knowledge, this is the first study on a slot antenna in the optical frequency.

Metal membrane with dimer slots as a universal polarizer

Science.gov (United States)

Zhukovsky, Sergej; Zalkovskij, Maksim; Malureanu, Radu; Kremers, Christian; Chigrin, Dmitry; Tang, Peter T.; Jepsen, Peter U.; Lavrinenko, Andrei V.

2014-03-01

In this work, we show theoretically and confirm experimentally that thin metal membranes patterned with an array of slot dimers (or their Babinet analogue with metal rods) can function as a versatile spectral and polarization filter. We present a detailed covariant multipole theory for the electromagnetic response of an arbitrary dimer based on the Green functions approach. The theory confirms that a great variety of polarization properties, such as birefringence, chirality and elliptical dichroism, can be achieved in a metal layer with such slot-dimer patterning (i.e. in a metasurface). Optical properties of the metasurface can be extensively tuned by varying the geometry (shape and dimensions) of the dimer, for example, by adjusting the sizes and mutual placement of the slots (e.g. inter-slot distance and alignment angle). Three basic shapes of dimers are analyzed: II-shaped (parallel slots), V-shaped, and T-shaped. These particular shapes of dimers are found to be sensitive to variations of the slots lengths and orientation of elements. Theoretical results are well supported by full-wave three-dimensional simulations. Our findings were verified experimentally on the metal membranes fabricated using UV lithography with subsequent Ni growth. Such metasurfaces were characterized using time-domain THz spectroscopy. The samples exhibit pronounced optical activity (500 degrees per wavelength) and high transmission: even though the slots cover only 4.3 % of the total membrane area the amplitude transmission reaches 0.67 at the resonance frequency 0.56 THz.

Humanizing machines: Anthropomorphization of slot machines increases gambling.

Science.gov (United States)

Riva, Paolo; Sacchi, Simona; Brambilla, Marco

2015-12-01

Do people gamble more on slot machines if they think that they are playing against humanlike minds rather than mathematical algorithms? Research has shown that people have a strong cognitive tendency to imbue humanlike mental states to nonhuman entities (i.e., anthropomorphism). The present research tested whether anthropomorphizing slot machines would increase gambling. Four studies manipulated slot machine anthropomorphization and found that exposing people to an anthropomorphized description of a slot machine increased gambling behavior and reduced gambling outcomes. Such findings emerged using tasks that focused on gambling behavior (Studies 1 to 3) as well as in experimental paradigms that included gambling outcomes (Studies 2 to 4). We found that gambling outcomes decrease because participants primed with the anthropomorphic slot machine gambled more (Study 4). Furthermore, we found that high-arousal positive emotions (e.g., feeling excited) played a role in the effect of anthropomorphism on gambling behavior (Studies 3 and 4). Our research indicates that the psychological process of gambling-machine anthropomorphism can be advantageous for the gaming industry; however, this may come at great expense for gamblers' (and their families') economic resources and psychological well-being. (c) 2015 APA, all rights reserved).

Slot Parameter Optimization for Multiband Antenna Performance Improvement Using Intelligent Systems

Directory of Open Access Journals (Sweden)

Erdem Demircioglu

2015-01-01

Full Text Available This paper discusses bandwidth enhancement for multiband microstrip patch antennas (MMPAs using symmetrical rectangular/square slots etched on the patch and the substrate properties. The slot parameters on MMPA are modeled using soft computing technique of artificial neural networks (ANN. To achieve the best ANN performance, Particle Swarm Optimization (PSO and Differential Evolution (DE are applied with ANN’s conventional training algorithm in optimization of the modeling performance. In this study, the slot parameters are assumed as slot distance to the radiating patch edge, slot width, and length. Bandwidth enhancement is applied to a formerly designed MMPA fed by a microstrip transmission line attached to the center pin of 50 ohm SMA connecter. The simulated antennas are fabricated and measured. Measurement results are utilized for training the artificial intelligence models. The ANN provides 98% model accuracy for rectangular slots and 97% for square slots; however, ANFIS offer 90% accuracy with lack of resonance frequency tracking.

Effects of geometry on slot-jet film cooling performance

Energy Technology Data Exchange (ETDEWEB)

Hyams, D.G.; McGovern, K.T.; Leylek, J.H. [Clemson Univ., SC (United States)

1995-10-01

The physics of the film cooling process for shaped, inclined slot-jets with realistic slot-length-to-width ratios (L/s) is studied for a range of blowing ratio (M) and density ratio (DR) parameters typical of gas turbine operations. For the first time in the open literature, the effect of inlet and exit shaping of the slot-jet on both flow and thermal field characteristics is isolated, and the dominant mechanisms responsible for differences in these characteristics are documented. A previously documented computational methodology was applied for the study of four distinct configurations: (1) slot with straight edges and sharp corners (reference case); (2) slot with shaped inlet region; (3) slot with shaped exit region; and (4) slot with both shaped inlet and exit regions. Detailed field results as well as surface phenomena involving adiabatic film effectiveness ({eta}) and heat transfer coefficient (h) are presented. It is demonstrated that both {eta} and h results are vital in the proper assessment of film cooling performance. All simulations were carried out using a multi-block, unstructured/adaptive grid, fully explicit, time-marching solver with multi-grid, local time stepping, and residual smoothing type acceleration techniques. Special attention was paid to and full documentation provided for: (1) proper modeling of the physical phenomena; (2) exact geometry and high quality grid generation techniques; (3) discretization schemes; and (4) turbulence modeling issues. The key parameters M and DR were varied from 1.0 to 2.0 and 1.5 to 2.0, respectively, to show their influence. Simulations were repeated for slot length-to-width ratio (L/s) of 3.0 and 4.5 in order to explain the effects of this important parameter. Additionally, the performance of two popular turbulence models, standard k-F, and RNG k-E, were studied to establish their ability to handle highly elliptic jet/crossflow interaction type processes.

Flexural and Thermal Properties of Novel Energy Conservation Slotted Reinforced Concrete Beams

Directory of Open Access Journals (Sweden)

Gao Ma

2016-01-01

Full Text Available Conventional solid reinforced concrete (RC beams were modified to slotted beams for consideration as thermal insulation structural components. The slotted beam consisted of an outer and an inner beam, respectively, with a slot located near the middle of the beam along its width direction for filling thermal insulation material. Flexural and thermal behavior of the slotted beams were investigated. Three RC reference solid beams and six slotted beams were fabricated and tested under four-point bending tests. The test results indicated that the failure mode of both slotted beams and the solid beams was flexural failure. However, the damage process of the slotted beams was different from that of the solid beams at the final loading stage. The moment curvature analysis indicated that the tensile reinforcement ratio of the outer and inner beams had an important effect on the flexural behavior, especially the ductility of the slotted beams. Thermal study indicated that the heat transfer coefficient of the slotted beam was greatly reduced and the thermal inertia factor increased a lot, compared with the solid beam. In addition, FE simulation results showed that a new frame structure using slotted beams exhibited obvious and attractive thermal insulation property.

Analysis and design of broadband U-slot cut rectangular microstrip ...

Indian Academy of Sciences (India)

AMIT A DESHMUKH

2017-07-15

Jul 15, 2017 ... Abstract. Broadband microstrip antenna using variations of U-slot has been widely reported. However, in most of the reported work, an in-depth explanation about the mode introduced by U-slot and procedure to design. U-slot cut antennas at any given frequency is not explained. In this paper, first an ...

Low-loss tunable 1D ITO-slot photonic crystal nanobeam cavity

Science.gov (United States)

Amin, Rubab; Tahersima, Mohammad H.; Ma, Zhizhen; Suer, Can; Liu, Ke; Dalir, Hamed; Sorger, Volker J.

2018-05-01

Tunable optical material properties enable novel applications in both versatile metamaterials and photonic components including optical sources and modulators. Transparent conductive oxides (TCOs) are able to highly tune their optical properties with applied bias via altering their free carrier concentration and hence plasma dispersion. The TCO material indium tin oxide (ITO) exhibits unity-strong index change and epsilon-near-zero behavior. However, with such tuning the corresponding high optical losses, originating from the fundamental Kramers–Kronig relations, result in low cavity finesse. However, achieving efficient tuning in ITO-cavities without using light–matter interaction enhancement techniques such as polaritonic modes, which are inherently lossy, is a challenge. Here we discuss a novel one-dimensional photonic crystal nanobeam cavity to deliver a cavity system offering a wide range of resonance tuning range, while preserving physical compact footprints. We show that a vertical silicon-slot waveguide incorporating an actively gated-ITO layer delivers ∼3.4 nm of tuning. By deploying distributed feedback, we are able to keep the Q-factor moderately high with tuning. Combining this with the sub-diffraction limited mode volume (0.1 (λ/2n)3) from the photonic (non-plasmonic) slot waveguide, facilitates a high Purcell factor exceeding 1000. This strong light–matter-interaction shows that reducing the mode volume of a cavity outweighs reducing the losses in diffraction limited modal cavities such as those from bulk Si3N4. These tunable cavities enable future modulators and optical sources such as tunable lasers.

Multiplexed Simultaneous High Sensitivity Sensors with High-Order Mode Based on the Integration of Photonic Crystal 1 × 3 Beam Splitter and Three Different Single-Slot PCNCs.

Science.gov (United States)

Zhou, Jian; Huang, Lijun; Fu, Zhongyuan; Sun, Fujun; Tian, Huiping

2016-07-07

We simulated an efficient method for the sensor array of high-sensitivity single-slot photonic crystal nanobeam cavities (PCNCs) on a silicon platform. With the combination of a well-designed photonic crystal waveguide (PhCW) filter and an elaborate single-slot PCNC, a specific high-order resonant mode was filtered for sensing. A 1 × 3 beam splitter carefully established was implemented to split channels and integrate three sensors to realize microarrays. By applying the three-dimensional finite-difference-time-domain (3D-FDTD) method, the sensitivities calculated were S₁ = 492 nm/RIU, S₂ = 244 nm/RIU, and S₃ = 552 nm/RIU, respectively. To the best of our knowledge, this is the first multiplexing design in which each sensor cite features such a high sensitivity simultaneously.

FDTD Analysis of U-Slot Rectangular Patch Antenna

Science.gov (United States)

Luk, K. M.; Tong, K. F.; Shum, S. M.; Lee, K. F.; Lee, R. Q.

1997-01-01

The U-slot rectangular patch antenna (Figure I) has been found experimentally to provide impedance and gain bandwidths of about 300 without the need of stacked or coplanar parasitic elements [1,2]. In this paper, simulation results of the U-slot patch using FDTD analysis are presented. Comparison with measured results are given.

Mechanism Design for Multi-slot Ads Auction in Sponsored Search Markets

Science.gov (United States)

Deng, Xiaotie; Sun, Yang; Yin, Ming; Zhou, Yunhong

In this paper, we study pricing models for multi-slot advertisements, where advertisers can bid to place links to their sales webpages at one or multiple slots on a webpage, called the multi-slot AD auction problem. We develop and analyze several important mechanisms, including the VCG mechanism for multi-slot ads auction, the optimal social welfare solution, as well as two weighted GSP-like protocols (mixed and hybrid). Furthermore, we consider that forward-looking Nash equilibrium and prove its existence in the weighted GSP-like pricing protocols.

Slotted Blades Savonius Wind Turbine Analysis by CFD

Directory of Open Access Journals (Sweden)

Andrea Alaimo

2013-12-01

Full Text Available In this paper a new bucket configuration for a Savonius wind generator is proposed. Numerical analyses are performed to estimate the performances of the proposed configuration by means of the commercial code COMSOL Multiphysics® with respect to Savonius wind turbine with overlap only. Parametric analyses are performed, for a fixed overlap ratio, by varying the slot position; the results show that for slot positioned near the blade root, the Savonius rotor improves performances at low tip speed ratio, evidencing a better starting torque. This circumstance is confirmed by static analyses performed on the slotted blades in order to investigate the starting characteristic of the proposed Savonius wind generator configuration.

Slots in dielectric image line as mode launchers and circuit elements

Science.gov (United States)

Solbach, K.

1981-01-01

A planar resonator model is used to investigate slots in the ground plane of dielectric image lines. An equivalent circuit representation of the slot discontinuity is obtained, and the launching efficiency of the slot as a mode launcher is analyzed. Slots are also shown to be useful in the realization of dielectric image line array antennas. It is found that the slot discontinuity can be shown as a T-junction of the dielectric image line and a metal waveguide. The launching efficiency is found to increase with the dielectric constant of the dielectric image line, exhibiting a maximum value for guides whose height is slightly less than half a wavelength in the dielectric medium. The measured launching efficiencies of low permittivity dielectric image lines are found to be in good agreement with calculated values

Discrete-Slots Models of Visual Working-Memory Response Times

Science.gov (United States)

Donkin, Christopher; Nosofsky, Robert M.; Gold, Jason M.; Shiffrin, Richard M.

2014-01-01

Much recent research has aimed to establish whether visual working memory (WM) is better characterized by a limited number of discrete all-or-none slots or by a continuous sharing of memory resources. To date, however, researchers have not considered the response-time (RT) predictions of discrete-slots versus shared-resources models. To complement the past research in this field, we formalize a family of mixed-state, discrete-slots models for explaining choice and RTs in tasks of visual WM change detection. In the tasks under investigation, a small set of visual items is presented, followed by a test item in 1 of the studied positions for which a change judgment must be made. According to the models, if the studied item in that position is retained in 1 of the discrete slots, then a memory-based evidence-accumulation process determines the choice and the RT; if the studied item in that position is missing, then a guessing-based accumulation process operates. Observed RT distributions are therefore theorized to arise as probabilistic mixtures of the memory-based and guessing distributions. We formalize an analogous set of continuous shared-resources models. The model classes are tested on individual subjects with both qualitative contrasts and quantitative fits to RT-distribution data. The discrete-slots models provide much better qualitative and quantitative accounts of the RT and choice data than do the shared-resources models, although there is some evidence for “slots plus resources” when memory set size is very small. PMID:24015956

Slotted Waveguide and Antenna Study for HPM and RF Applications

Science.gov (United States)

2017-07-25

conventional rectangular slot arrays. The proposed CSR-SW A provided higher peak gain than the conventional lambda /4 rectangu lar slot array and a...more compact s ize (55% size reductjon) compared to the lambda /2 rectangular slot array. Both the theoretic and measured results suggest a return loss...in terms of scattering matrix S is: (I-8) With the scattering matrix S, we can compute the scattering field at any position. The resonance of SCCR

Geothermal reservoirs. Position of slotted section of the tube casing

International Nuclear Information System (INIS)

Carotenuto, A.; Vanoli, L.; Casarosa, C.

1999-01-01

In the present work the authors have verified the influence of the position of slotted section casing on heat rate drawn by plants for exploitation of geothermal reservoirs that use heat exchangers placed at the bottom of the well (DHE). This study have been done modelling numerically the aquifer, by means of finite element method, evaluating the heat rate drawn by the heat exchanger at different position of the slotted section of the tube casing. Numerical calculations have allowed to show the influence of the main characteristics of the aquifer and of the main characteristics of the aquifer and of the plant on design of the slotted section of the tube casing. In particular, the authors have studied the influence of i) equivalent conductivity and permeability of the aquifer, ii) mass flow rate and the inlet and outlet aquifer temperature difference in the well, iii) the ratio between the length of the slotted section and the thickness of the geothermal layer, varying the position of the slotted section of the tube casing in the aquifer [it

Vertically Polarized Omnidirectional Printed Slot Loop AntennaPrinted Slot Loop Antenna (invited)

DEFF Research Database (Denmark)

Kammersgaard, Nikolaj Peter Iversen; Kvist, Søren Helstrup; Thaysen, Jesper

2015-01-01

and in-phase fields in the slot in order to obtain an omnidirectional radiation pattern. The antenna is designed for the 2.45 GHz Industrial, Scientific and Medical band. Applications of the antenna are many. One is for on-body applications since it is ideal for launching a creeping waves due...

Vision-Based Parking-Slot Detection: A Benchmark and A Learning-Based Approach

Directory of Open Access Journals (Sweden)

Lin Zhang

2018-03-01

Full Text Available Recent years have witnessed a growing interest in developing automatic parking systems in the field of intelligent vehicles. However, how to effectively and efficiently locating parking-slots using a vision-based system is still an unresolved issue. Even more seriously, there is no publicly available labeled benchmark dataset for tuning and testing parking-slot detection algorithms. In this paper, we attempt to fill the above-mentioned research gaps to some extent and our contributions are twofold. Firstly, to facilitate the study of vision-based parking-slot detection, a large-scale parking-slot image database is established. This database comprises 8600 surround-view images collected from typical indoor and outdoor parking sites. For each image in this database, the marking-points and parking-slots are carefully labeled. Such a database can serve as a benchmark to design and validate parking-slot detection algorithms. Secondly, a learning-based parking-slot detection approach, namely P S D L , is proposed. Using P S D L , given a surround-view image, the marking-points will be detected first and then the valid parking-slots can be inferred. The efficacy and efficiency of P S D L have been corroborated on our database. It is expected that P S D L can serve as a baseline when the other researchers develop more sophisticated methods.

Modeling of Slot Waveguide Sensors Based on Polymeric Materials

Science.gov (United States)

Bettotti, Paolo; Pitanti, Alessandro; Rigo, Eveline; De Leonardis, Francesco; Passaro, Vittorio M. N.; Pavesi, Lorenzo

2011-01-01

Slot waveguides are very promising for optical sensing applications because of their peculiar spatial mode profile. In this paper we have carried out a detailed analysis of mode confinement properties in slot waveguides realized in very low refractive index materials. We show that the sensitivity of a slot waveguide is not directly related to the refractive index contrast of high and low materials forming the waveguide. Thus, a careful design of the structures allows the realization of high sensitivity devices even in very low refractive index materials (e.g., polymers) to be achieved. Advantages of low index dielectrics in terms of cost, functionalization and ease of fabrication are discussed while keeping both CMOS compatibility and integrable design schemes. Finally, applications of low index slot waveguides as substitute of bulky fiber capillary sensors or in ring resonator architectures are addressed. Theoretical results of this work are relevant to well established polymer technologies. PMID:22164020

Modeling of Slot Waveguide Sensors Based on Polymeric Materials

Directory of Open Access Journals (Sweden)

Lorenzo Pavesi

2011-07-01

Full Text Available Slot waveguides are very promising for optical sensing applications because of their peculiar spatial mode profile. In this paper we have carried out a detailed analysis of mode confinement properties in slot waveguides realized in very low refractive index materials. We show that the sensitivity of a slot waveguide is not directly related to the refractive index contrast of high and low materials forming the waveguide. Thus, a careful design of the structures allows the realization of high sensitivity devices even in very low refractive index materials (e.g., polymers to be achieved. Advantages of low index dielectrics in terms of cost, functionalization and ease of fabrication are discussed while keeping both CMOS compatibility and integrable design schemes. Finally, applications of low index slot waveguides as substitute of bulky fiber capillary sensors or in ring resonator architectures are addressed. Theoretical results of this work are relevant to well established polymer technologies.

Investigation of slot discharge on a 239 MVA hydro generator stator winding

Energy Technology Data Exchange (ETDEWEB)

Li, S.; Hong, W. [BC Hydro and Power Authority, Vancouver, BC (Canada)

2009-07-01

This paper discussed a slot discharge investigation conducted on a 239 MVA generator stator winding. The generator in which the winding was located had experienced core split distortion, stator winding phase-to-phase failures, winding failures during Hipot testing, and high partial discharge (PD) activity. The results of on-line PD testing data were evaluated. The stator winding was subjected to visual inspections, bar dissections, and failure mechanism analyses. Eleven winding bars were removed from the stator slots in order to assess groundwall insulation conditions and identify the cause of the slot discharge activity. It was determined that the root cause of the slot discharge was a loose, non-uniform bar in the slot. The vibrating bar caused the semi-conductive coating to wear out and degraded the armour tape. Results of the study demonstrated the importance of on-line PD monitoring for detecting slot PD activity. 4 refs., 3 tabs., 11 figs.

Collaborative en-route and slot allocation algorithm based on fuzzy comprehensive evaluation

Science.gov (United States)

Yang, Shangwen; Guo, Baohua; Xiao, Xuefei; Gao, Haichao

2018-01-01

To allocate the en-routes and slots to the flights with collaborative decision making, a collaborative en-route and slot allocation algorithm based on fuzzy comprehensive evaluation was proposed. Evaluation indexes include flight delay costs, delay time and the number of turning points. Analytic hierarchy process is applied to determining index weights. Remark set for current two flights not yet obtained the en-route and slot in flight schedule is established. Then, fuzzy comprehensive evaluation is performed, and the en-route and slot for the current two flights are determined. Continue selecting the flight not yet obtained an en-route and a slot in flight schedule. Perform fuzzy comprehensive evaluation until all flights have obtained the en-routes and slots. MatlabR2007b was applied to numerical test based on the simulated data of a civil en-route. Test results show that, compared with the traditional strategy of first come first service, the algorithm gains better effect. The effectiveness of the algorithm was verified.

Multiplexed Simultaneous High Sensitivity Sensors with High-Order Mode Based on the Integration of Photonic Crystal 1 × 3 Beam Splitter and Three Different Single-Slot PCNCs

Directory of Open Access Journals (Sweden)

Jian Zhou

2016-07-01

Full Text Available We simulated an efficient method for the sensor array of high-sensitivity single-slot photonic crystal nanobeam cavities (PCNCs on a silicon platform. With the combination of a well-designed photonic crystal waveguide (PhCW filter and an elaborate single-slot PCNC, a specific high-order resonant mode was filtered for sensing. A 1 × 3 beam splitter carefully established was implemented to split channels and integrate three sensors to realize microarrays. By applying the three-dimensional finite-difference-time-domain (3D-FDTD method, the sensitivities calculated were S1 = 492 nm/RIU, S2 = 244 nm/RIU, and S3 = 552 nm/RIU, respectively. To the best of our knowledge, this is the first multiplexing design in which each sensor cite features such a high sensitivity simultaneously.

Guided acoustic and optical waves in silicon-on-insulator for Brillouin scattering and optomechanics

Directory of Open Access Journals (Sweden)

Christopher J. Sarabalis

2016-10-01

Full Text Available We numerically study silicon waveguides on silica showing that it is possible to simultaneously guide optical and acoustic waves in the technologically important silicon on insulator (SOI material system. Thin waveguides, or fins, exhibit geometrically softened mechanical modes at gigahertz frequencies with phase velocities below the Rayleigh velocity in glass, eliminating acoustic radiation losses. We propose slot waveguides on glass with telecom optical frequencies and strong radiation pressure forces resulting in Brillouin gains on the order of 500 and 50 000 W−1m−1 for backward and forward Brillouin scattering, respectively.

A multi-slot surface coil for MRI of dual-rat imaging at 4 T

International Nuclear Information System (INIS)

Solis, S E; Rodriguez, A O; Wang, R; Tomasi, D

2011-01-01

A slotted surface coil inspired by the hole-and-slot cavity magnetron was developed for magnetic resonance imaging of obese rats at 4 T. Full-wave analysis of the magnetic field was carried out at 170 MHz for both the slotted and circular-shaped coils. The noise figure values of two coils were investigated via the numerical calculation of the quality factors. Fat simulated phantoms to mimic overweight rats were included in the analysis with weights ranging from 300 to 900 g. The noise figures were 1.2 dB for the slotted coil and 2.4 dB for the circular coil when loaded with 600 g of simulated phantom. A slotted surface coil with eight circular slots and a circular coil with similar dimensions were built and operated in the transceiver mode, and their performances were experimentally compared. The imaging tests in phantoms demonstrated that the slotted surface coil has a deeper RF-sensitivity and better field uniformity than the single-loop RF-coil. High quality images of two overweight Zucker rats were acquired simultaneously with the slotted surface coil using standard spin-echo pulse sequences. Experimental results showed that the slotted surface coil outperformed the circular coil for imaging considerably overweight rats. Thus, the slotted surface coil can be a good tool for MRI experiments in rats on a human whole-body 4 T scanner.

A multi-slot surface coil for MRI of dual-rat imaging at 4T

Energy Technology Data Exchange (ETDEWEB)

Solis, S.E.; Tomasi, D.; Solis, S.E.; Wang, R.; Tomasi, D.; Rodriguez, A.O.

2011-07-01

A slotted surface coil inspired by the hole-and-slot cavity magnetron was developed for magnetic resonance imaging of obese rats at 4 T. Full-wave analysis of the magnetic field was carried out at 170 MHz for both the slotted and circular-shaped coils. The noise figure values of two coils were investigated via the numerical calculation of the quality factors. Fat simulated phantoms to mimic overweight rats were included in the analysis with weights ranging from 300 to 900 g. The noise figures were 1.2 dB for the slotted coil and 2.4 dB for the circular coil when loaded with 600 g of simulated phantom. A slotted surface coil with eight circular slots and a circular coil with similar dimensions were built and operated in the transceiver mode, and their performances were experimentally compared. The imaging tests in phantoms demonstrated that the slotted surface coil has a deeper RF-sensitivity and better field uniformity than the single-loop RF-coil. High quality images of two overweight Zucker rats were acquired simultaneously with the slotted surface coil using standard spin-echo pulse sequences. Experimental results showed that the slotted surface coil outperformed the circular coil for imaging considerably overweight rats. Thus, the slotted surface coil can be a good tool for MRI experiments in rats on a human whole-body 4 T scanner.

A multi-slot surface coil for MRI of dual-rat imaging at 4 T

Energy Technology Data Exchange (ETDEWEB)

Solis, S E; Rodriguez, A O [Departamento de Ingenieria Electrica, Universidad Autonoma Metropolitana Iztapalapa, Mexico, DF 09340 (Mexico); Wang, R; Tomasi, D, E-mail: arog@xanum.uam.mx [Medical Department, Brookhaven National Laboratory, Upton, NY 11973 (United States)

2011-06-21

A slotted surface coil inspired by the hole-and-slot cavity magnetron was developed for magnetic resonance imaging of obese rats at 4 T. Full-wave analysis of the magnetic field was carried out at 170 MHz for both the slotted and circular-shaped coils. The noise figure values of two coils were investigated via the numerical calculation of the quality factors. Fat simulated phantoms to mimic overweight rats were included in the analysis with weights ranging from 300 to 900 g. The noise figures were 1.2 dB for the slotted coil and 2.4 dB for the circular coil when loaded with 600 g of simulated phantom. A slotted surface coil with eight circular slots and a circular coil with similar dimensions were built and operated in the transceiver mode, and their performances were experimentally compared. The imaging tests in phantoms demonstrated that the slotted surface coil has a deeper RF-sensitivity and better field uniformity than the single-loop RF-coil. High quality images of two overweight Zucker rats were acquired simultaneously with the slotted surface coil using standard spin-echo pulse sequences. Experimental results showed that the slotted surface coil outperformed the circular coil for imaging considerably overweight rats. Thus, the slotted surface coil can be a good tool for MRI experiments in rats on a human whole-body 4 T scanner.

Energy characteristics of the double slot in the narrow wall of a rectangular waveguide

OpenAIRE

Martynenko, S. A.

2005-01-01

Based on approximation of the half-wave field distribution in the slots, an expression is derived for internal mutual conductance of closely-spaced slots, which form a double inclined slot in the narrow wall of a rectangular waveguide. The narrow wall has cut-outs reaching the broad wall. With the use of the method of induced magnetomotive forces, a mathematical model is devised for calculating the energy characteristics of the double slot. The impact of angle of inclination of the slots, dim...

Transmission-enabled fiber Fabry-Perot cavity based on a deeply etched slotted micromirror.

Science.gov (United States)

Othman, Muhammad A; Sabry, Yasser M; Sadek, Mohamed; Nassar, Ismail M; Khalil, Diaa A

2018-06-01

In this work, we report the analysis, fabrication, and characterization of an optical cavity built using a Bragg-coated fiber (BCF) mirror and a metal-coated microelectromechanical systems (MEMS) slotted micromirror, where the latter allows transmission output from the cavity. Theoretical modeling, using Fourier optics analysis for the cavity response based on tracing the propagation of light back and forth between the mirrors, is presented. Detailed simulation analysis is carried out for the spectral response of the cavity under different design conditions. MEMS chips of the slotted micromirror are fabricated using deep reactive ion etching of a silicon-on-insulator substrate with different device-etching depths of 150 μm and 80 μm with aluminum and gold metal coating, respectively. The cavity is characterized as an optical filter using a BCF with reflectivity that is larger than 95% in a 300 nm range across the E-band and the L-band. Versatile filter characteristics were obtained for different values of the MEMS micromirror slit width and cavity length. A free spectral range (FSR) of about 33 nm and a quality factor of about 196 were obtained for a 5.5 μm width aluminum slit, while an FSR of about 148 nm and a quality factor of about 148 were obtained for a 1.5 μm width gold slit. The presented structure opens the door for wide spectral response transmission-type MEMS filters.

Broadcast Coded Slotted ALOHA

DEFF Research Database (Denmark)

Ivanov, Mikhail; Brännström, Frederik; Graell i Amat, Alexandre

2016-01-01

We propose an uncoordinated medium access control (MAC) protocol, called all-to-all broadcast coded slotted ALOHA (B-CSA) for reliable all-to-all broadcast with strict latency constraints. In B-CSA, each user acts as both transmitter and receiver in a half-duplex mode. The half-duplex mode gives ...

Results of pressurized-slot measurements in the G-Tunnel underground facility

International Nuclear Information System (INIS)

Zimmerman, R.M.; Mann, K.L.; Dodds, D.J.

1989-01-01

A rock-mechanics field-testing program is underway at Sandia National Laboratories (SNL) as part of the YMP. SNL has the responsibility for assessing the repository design and performance as well as characterizing the geomechanical behavior of the rock. SNL has conducted field experiments in G-Tunnel in Rainier Mesa at the NTS, where tuffs similar to those at Yucca Mountain, the potential repository site, are found. Later experiments are planned as part of the YMP Exploratory Shaft investigations at Yucca Mountain. Major geomechanical factors in repository developments are determinations of the stress state and the deformability of the rock mass (described by the modulus of deformation). One feature of SNL's rock-mechanics program was the development of a testing program for cutting thin slots in a jointed welded tuff and utilizing flatjacks for pressurizing these thin-slots on a relatively, large scale. Objectives in the pressurized-slot testing in G-Tunnel have been to apply and possibly improve methods for (1) utilizing the flatjack cancellation (FC) method for measuring stresses normal to the slot and (2) measuring the modulus of deformation of the jointed rock surrounding the slot. This paper discusses the results of field measurements in and around a single slot and evaluates potential applications and limitations. 10 refs., 1 fig., 4 tabs

Slot-dimer babinet metamaterials as polarization shapers for terahertz waves

DEFF Research Database (Denmark)

Zhukovsky, Sergei; Chigrin, D. N.; Lavrinenko, Andrei

2013-01-01

We theoretically study optical properties of free-standing metallic membranes patterned with an array of two-slot elements (dimers) comprising two rectangular slots of different dimensions and orientation. It is shown that these structures feature extraordinary optical transmission with strong...

Engineered SOI slot waveguide ring resonator V-shape resonance combs for refraction index sensing up to 1300nm/RIU (Conference Presentation)

Science.gov (United States)

Zhang, Weiwei; Serna, Samuel; Le Roux, Xavier; Vivien, Laurent; Cassan, Eric

2016-05-01

Bio-detection based on CMOS technology boosts the miniaturization of detection systems and the success on highly efficient, robust, accurate, and low coast Lab-on-Chip detection schemes. Such on chip detection technologies have covered healthy related harmful gases, bio-chemical analytes, genetic micro RNA, etc. Their monitoring accuracy is mainly qualified in terms of sensitivity and limit of the detection (LOD) of the detection system. In this context, recently developed silicon on insulator (SOI) optical devices have displayed highly performant detection abilities that LOD could go beyond 10-8RIU and sensitivity could exceeds 103nm/RIU. The SOI integrated optical sensing devices include strip/slotted waveguide consisting in structures like Mach-Zehnder interferometers (MZI), ring resonators (RR), nano cavities, etc. Typically, hollow core RR and nano-cavities could exhibit higher sensitivity due to their optical mode confinement properties with a partial localization of the electric field in low index sensing regions than devices based on evanescent field tails outside of the optical cores. Furthermore, they also provide larger sensing areas for surface functionalization to reach higher sensitivities and lower LODs. The state of art of hollow core devices, either based on Bragg gratings formed from a slot waveguide cavity or photonic crystal slot cavities, show sensitivities (S) up to 400nm/RIU and Figure of Merit (FOM) around 3,000 in water environment, FOM being defined as the inverse of LOD and precisely as FOM=SQ/λ, with λ the resonance wavelength and Q the quality factor of the considered resonator. Such high achieved FOMs in nano cavities are mainly due to their large Q factors around 15,000. While for mostly used RR, which do not require particular design strategies, relatively low Q factors around 1800 in water are met and moderate sensitivities about 300nm/RIU are found. In this work, we present here a novel slot ring resonator design to make

Crossed-Slot Cavity-Backed Antenna with Improved Hemispherical Coverage

DEFF Research Database (Denmark)

Kim, Oleksiy S.; Breinbjerg, Olav; Østergaard, Allan

2005-01-01

The paper presents the results of the investigation of the crossed-slot cavity-backed antenna with the complementary crossed electric dipoles added to compensate the circularly polarized (CP) radiation pattern degradation near the horizon. Dependences of the radiation characteristics...... of the modified crossed-slot cavity-backed antenna on the length, width and height of the crossed electric dipoles are shown. Effects of a finite size ground plane are taken into account due to a full wave electromagnetic analysis software utilized in the parametrical investigations. Simulated and measured...... results for a selected antenna configuration prove that the properly adjusted crossed electric dipoles are able to improve the coverage and CP polarization characteristics of the crossed-slot cavity-backed antenna....

Measurement of the depth of narrow slotted sections in eddy current reference standards

Science.gov (United States)

Kim, Young-Joo; Kim, Young-gil; Ahn, Bongyoung; Yoon, Dong-Jin

2007-02-01

The dimensions of the slots in eddy current (EC) reference standards are too narrow to be measured by general depth measurement methods such as the optical (laser) or stylus methods. However, measurement of the dimensions of the machined slots is a prerequisite to using the blocks as references. The present paper suggests a measurement method for the slotted section using an ultrasonic test. The width and depth of the slots measured in our study are roughly 0.1 mm and 0.5 mm, respectively. The time of flight (TOF) of the ultrasonic wave was measured precisely. The ultrasonic velocity in the material of the EC reference standard was calculated with the measured values of the TOF and its thickness. Reflected waves from the tip of the slot and the bottom surface of the EC standard were successfully classified. Using this method we have successfully determined the depth of the slotted section.

Slot-type pickup/kicker for AA stochastic cooling

CERN Multimedia

CERN PhotoLab

1979-01-01

A "slotted transmission line" was used for both pickups and kickers of the cooling systems of the AA. They served for the cooling of the high-density antiproton stack, in momentum and both transverse planes. In the beginning in a single band, 1-2 GHz, later in 2 bands, 2-4 and 4-8 GHz. Here we see the slotted electrodes partly pulled out of the outer casing. See also 7906189, 7906581X, 7896193.

Slot opening optimization of surface mounted permanent magnet motor for cogging torque reduction

International Nuclear Information System (INIS)

Abbaszadeh, K.; Rezaee Alam, F.; Teshnehlab, M.

2012-01-01

Highlights: ► The slot opening shift method is an efficient method for cogging torque reduction. ► Using slot opening skew method, the trapezoidal waveform of back-emf is maintained. ► Using the conventional slot skewing, the wave shape of back-emf is sinusoidal. ► The novelty of paper is using of air–gap permeance harmonics as objective function. ► Other novelty of this paper is using the different optimization algorithms. - Abstract: In this paper, slot opening skew method is used for cogging torque reduction. A three layer stator model is considered for a six-pole PM-BLDC motor (a PM-BLDC motor with 18-slots, six-poles and length of 5 cm) and then a 2D dual model is extracted for this 3D slot opening skew model. The angular shifts of slot opening position in the first and third layers than middle layer are considered as optimization parameters. Slot opening shape is optimized by using different optimization algorithms, such as, the response surface methodology (RSM), the genetic algorithm (GA) and the particle swarm optimization (PSO). In order to using of GA and PSO, the analytical relationship is derived for the air–gap permeance function. The optimization results of these algorithms are being consistent with each other and are verified with FEA results. The results show the significant reduction of cogging torque about 77%.

Congestion Pricing for Aircraft Pushback Slot Allocation

Science.gov (United States)

Zhang, Yaping

2017-01-01

In order to optimize aircraft pushback management during rush hour, aircraft pushback slot allocation based on congestion pricing is explored while considering monetary compensation based on the quality of the surface operations. First, the concept of the “external cost of surface congestion” is proposed, and a quantitative study on the external cost is performed. Then, an aircraft pushback slot allocation model for minimizing the total surface cost is established. An improved discrete differential evolution algorithm is also designed. Finally, a simulation is performed on Xinzheng International Airport using the proposed model. By comparing the pushback slot control strategy based on congestion pricing with other strategies, the advantages of the proposed model and algorithm are highlighted. In addition to reducing delays and optimizing the delay distribution, the model and algorithm are better suited for use for actual aircraft pushback management during rush hour. Further, it is also observed they do not result in significant increases in the surface cost. These results confirm the effectiveness and suitability of the proposed model and algorithm. PMID:28114429

Congestion Pricing for Aircraft Pushback Slot Allocation.

Science.gov (United States)

Liu, Lihua; Zhang, Yaping; Liu, Lan; Xing, Zhiwei

2017-01-01

In order to optimize aircraft pushback management during rush hour, aircraft pushback slot allocation based on congestion pricing is explored while considering monetary compensation based on the quality of the surface operations. First, the concept of the "external cost of surface congestion" is proposed, and a quantitative study on the external cost is performed. Then, an aircraft pushback slot allocation model for minimizing the total surface cost is established. An improved discrete differential evolution algorithm is also designed. Finally, a simulation is performed on Xinzheng International Airport using the proposed model. By comparing the pushback slot control strategy based on congestion pricing with other strategies, the advantages of the proposed model and algorithm are highlighted. In addition to reducing delays and optimizing the delay distribution, the model and algorithm are better suited for use for actual aircraft pushback management during rush hour. Further, it is also observed they do not result in significant increases in the surface cost. These results confirm the effectiveness and suitability of the proposed model and algorithm.

Congestion Pricing for Aircraft Pushback Slot Allocation.

Directory of Open Access Journals (Sweden)

Lihua Liu

Full Text Available In order to optimize aircraft pushback management during rush hour, aircraft pushback slot allocation based on congestion pricing is explored while considering monetary compensation based on the quality of the surface operations. First, the concept of the "external cost of surface congestion" is proposed, and a quantitative study on the external cost is performed. Then, an aircraft pushback slot allocation model for minimizing the total surface cost is established. An improved discrete differential evolution algorithm is also designed. Finally, a simulation is performed on Xinzheng International Airport using the proposed model. By comparing the pushback slot control strategy based on congestion pricing with other strategies, the advantages of the proposed model and algorithm are highlighted. In addition to reducing delays and optimizing the delay distribution, the model and algorithm are better suited for use for actual aircraft pushback management during rush hour. Further, it is also observed they do not result in significant increases in the surface cost. These results confirm the effectiveness and suitability of the proposed model and algorithm.

Slotted cage resonator for high-field magnetic resonance imaging of rodents

Energy Technology Data Exchange (ETDEWEB)

Marrufo, O; Vasquez, F; Solis, S E; Rodriguez, A O, E-mail: arog@xanum.uam.mx [Departamento de Ingenieria Electrica, Universidad Autonoma Metropolitana Iztapalapa, Mexico, DF 09340 (Mexico)

2011-04-20

A variation of the high-frequency cavity resonator coil was experimentally developed according to the theoretical frame proposed by Mansfield in 1990. Circular slots were used instead of cavities to form the coil endplates and it was called the slotted cage resonator coil. The theoretical principles were validated via a coil equivalent circuit and also experimentally with a coil prototype. The radio frequency magnetic field, B1, produced by several coil configurations was numerically simulated using the finite-element approach to investigate their performances. A transceiver coil, 8 cm long and 7.6 cm in diameter, and composed of 4 circular slots with a 15 mm diameter on both endplates, was built to operate at 300 MHz and quadrature driven. Experimental results obtained with the slotted cage resonator coil were presented and showed very good agreement with the theoretical expectations for the resonant frequency as a function of the coil dimensions and slots. A standard birdcage coil was also built for performance comparison purposes. Phantom images were then acquired to compute the signal-to-noise ratio of both coils showing an important improvement of the slotted cage coil over the birdcage coil. The whole-body images of the mouse were also obtained showing high-quality images. Volume resonator coils can be reliably built following the physical principles of the cavity resonator design for high-field magnetic resonance imaging applications of rodents.

Evaluation of two styles of slotted, flat-head screws

International Nuclear Information System (INIS)

Reeves, C.A. Jr.; Johnson, W.B.

1979-01-01

A series of torque tests were performed to evaluate the relative merits of two different flat-head screws fabricated from a uranium--6% niobium alloy. The screws tested were machined with both normal, straight-through slots in the head and with slots having radiused bottoms. Test results indicate that both designs easily surpass the required 20-inch-pound-proof torque

Development of high power models of four-slot Annular Coupled Structure

International Nuclear Information System (INIS)

Kageyama, T.; Morozumi, Y.; Yoshino, K.; Yamazaki, Y.

1994-01-01

A π/2-mode standing-wave linac (f=1.296 GHz) of an Annular Coupled Structure (ACS) has been developed for the 1-GeV proton linac of the Japanese Hadron Project (JHP). This ACS has four coupling slots between accelerating and coupling cells in order to suppress higher order mode mixing with the π/2 coupling mode. High-β(β=v/c=0.78) and low-β(0.52) prototypes were constructed and tested up to each design RF power. Concerning the effect of the coupling slots on the fields of a coupled-cavity linac, it was found that the slot configuration of the side-coupled structure (SCS) tilts the accelerating field. On the other hand, the four-slot configuration of the ACS gives an almost axially symmetric accelerating field to the beam. (author)

High slot utilization systems for electric machines

Science.gov (United States)

Hsu, John S

2009-06-23

Two new High Slot Utilization (HSU) Systems for electric machines enable the use of form wound coils that have the highest fill factor and the best use of magnetic materials. The epoxy/resin/curing treatment ensures the mechanical strength of the assembly of teeth, core, and coils. In addition, the first HSU system allows the coil layers to be moved inside the slots for the assembly purpose. The second system uses the slided-in teeth instead of the plugged-in teeth. The power density of the electric machine that uses either system can reach its highest limit.

Optical Waveform Sampling and Error-Free Demultiplexing of 1.28 Tb/s Serial Data in a Nanoengineered Silicon Waveguide

DEFF Research Database (Denmark)

Ji, Hua; Pu, Minhao; Hu, Hao

2011-01-01

This paper presents the experimental demonstrations of using a pure nanoengineered silicon waveguide for 1.28 Tb/s serial data optical waveform sampling and 1.28 Tb/s–10 Gb/s error free demultiplexing. The 330-fs pulses are resolved in each 780-fs time slot in waveform sampling. Error...

Improvement The Transmission Efficiency For Wireless Packet Communication Systems Using Automatic Control for power And Time Slot Width Of Slotted Non persistent ISMA Protocol

Directory of Open Access Journals (Sweden)

Saad M. Hardan

2013-05-01

Full Text Available In packed communication systems which use a protocol, the protocol should perform the allocation of channels such that the transmission channel is used efficiently. Efficiency is usually measured in terms of channel throughput and the average transmission  delay. The Slotted Nonpersistent ISMA protocol is one of random access protocols used in packed communication systems. In this research a Slotted Nonpersistent ISMA protocol Model with automatic control for power and time slot is proposed. the suggested algorithm enable the base station(access point to control  the protocol time slot length and  transmission power in a dynamic way to control the normalized propagation delay d and to maintain all the uplink signals in the limit of captured power threshold (capture ratio in order to control the  throughput and the average transmission delay of the communication system by an automatic method. the computer simulation results  confirm the activity of the  proposed algorithm for increasing the  throughput and decreasing the average transmission delay by an accepted ratios.

Bead beavior in a non-continues slot die coating regime

NARCIS (Netherlands)

Langen, A.; Senes, A.; Vries, I. de; Groen, P.

2015-01-01

Sheet-to-sheet slot die coating is a crucial intermediate technique to bring organic and large area electronics (e.g. OLED and Flexible OPV) towards mass roll-to-roll productions. The coating on substrate has to be uniform within nanometers. Additional settings are added to the slot die coater for a

Development of an economical and ecological optimized multi slot fish bypass

International Nuclear Information System (INIS)

Tauber, M.; Mader, H.

2009-01-01

The European Union's Water Framework Directive (WFD), which came into force in 2000, represents a new framework governing water policies. The ecological objectives of the directive are sometimes in conflict with the historical use of waterbodies for hydropower generation. This paper discussed the mitigation of negative economical effects caused by outfitting hydropower plants with fish migration facilities claimed by the WFD. In particular, it reviewed the new modified version of the Vertical Slot Fishpass which reduces water discharge while maintaining or even enhancing the biological migration of aquatic species. Reducing the flow rate in the fish bypass results in more available water for hydropower generation, which is economically advantageous for operators. The available water resource is simply used more efficiently. The bypass was modified by adding additional slot baffles and guide walls in order to induce intended losses at roughness obstacles and to obtain isolated roughness current in the multi slot area. A Froude similarity model was used to obtain the results of the first phase of this project. Different arrangements of the slot baffles and locations were measured. The results of all trials revealed that the newly developed multi slot variants have clear advantages over conventional vertical slot fish passages. Discharge was reduced by up to 34 per cent while still maintaining the same water levels in the pools. As such, the general flow velocities were also reduced by about 10 per cent, thereby achieving the primary objective of the project. 7 refs., 18 figs

A model of gas flow with friction in a slotted seal

Directory of Open Access Journals (Sweden)

Joachimiak Damian

2016-09-01

Full Text Available The paper discusses thermodynamic phenomena accompanying the flow of gas in a slotted seal. The analysis of the gas flow has been described based on an irreversible adiabatic transformation. A model based on the equation of total enthalpy balance has been proposed. The iterative process of the model aims at obtaining such a gas temperature distribution that will fulfill the continuity equation. The model allows for dissipation of the kinetic energy into friction heat by making use of the Blasius equation to determine the friction coefficient. Within the works, experimental research has been performed of the gas flow in a slotted seal of slot height 2 mm. Based on the experimental data, the equation of local friction coefficient was modified with a correction parameter. This parameter was described with the function of pressure ratio to obtain a mass flow of the value from the experiment. The reason for taking up of this problem is the absence of high accuracy models for calculating the gas flow in slotted seals. The proposed model allows an accurate determination of the mass flow in a slotted seal based on the geometry and gas initial and final parameters.

Modeling fiber motion in a pulp pressure screen: the effect of slot shape

International Nuclear Information System (INIS)

Dong, S.; Salcudean, M.; Gartshore, I.

2003-01-01

A pressure screen is a piece of equipment in the pulp and paper industry used either to remove contaminants from the pulp suspension or to separate fibers having different properties. Contaminants such as fiber bundles, bark and plastic specks are introduced when fibers are separated from the wood by mechanical or chemical pulping processes. Contaminants significantly affect the strength and smoothness of the paper and must be removed before the final paper is produced. The screen plate is a critical part of the pressure screen and its design is the key to screen performance. This paper uses a new and comprehensive CFD simulation tool to examine the flow and fiber behavior in a single slot screen having any reasonable slot shape. -This simulation tool includes three coupled models: first, the flow model solves the Reynolds Averaged Navier-Stokes (RANS) equation using the standard k - ε turbulence model to predict the flow field in the equipment. Second, a three-dimensional flexible fiber model is used to track the fiber trajectory in the screen. Third, a very general wall model is used to deal with the case when a fiber touches the equipment wall. The simulated results show that the slot shape has a critical influence on fiber behavior and screen performance. Three general slot shapes were investigated: the smooth slot, the step-step contour slot and slope-slope contour slot. Of these the slope-slope contour slot provides the best passage for the fibers with a length of 1mm and 3mm. (author)

Study on wake structure characteristics of a slotted micro-ramp with large-eddy simulation

Energy Technology Data Exchange (ETDEWEB)

Dong, Xiangrui; Chen, Yaohui; Dong, Gang; Liu, Yixin, E-mail: cyh873@163.com [National Key Laboratory of Transient Physics, Nanjing University of Science and Technology, Nanjing, 210094 (China)

2017-06-15

In this paper, a novel slotted ramp-type micro vortex generator (slotted micro-ramp) for flow separation control is simulated in the supersonic flow of Ma = 1.5, based on large eddy simulation combined with the finite volume method. The wake structure characteristics and control mechanisms of both slotted and standard micro-ramps are presented and discussed. The results show that the wake of standard micro-ramp includes a primary counter-rotating streamwise vortex pair, a train of vortex rings, and secondary vortices. The slotted micro-ramp has more complicated wake structures, which contain a confluent counter-rotating streamwise vortex pair and additional streamwise vortices, with the same rotation generated by slot and the vortex rings enveloping the vortex pair. The additional vortices generated by the slot of the micro-ramp can mix with the primary counter-rotating vortex pair, extend the life time, and strengthen the vortex intensity of primary vortex pair. Moreover, the slot can effectively alleviate, or even eliminate the backflow and decrease the profile drag induced by the standard micro-ramp, therefore improving the efficiency of separation control. (paper)

Slot technique - an alternative method of scatter reduction in radiography

International Nuclear Information System (INIS)

Panzer, W.; Widenmann, L.

1983-01-01

The most common method of scatter reduction in radiography is the use of an antiscatter grid. Its disadvantage is the absorption of a certain percentage of primary radiation in the lead strips of the grid and the fact that due to the limited thickness of the lead strips their scatter absorption is also limited. A possibility for avoiding this disadvantage is offered by the so-called slot technique, ie, the successive exposure of the subject with a narrow fan beam provided by slots in rather thick lead plates. The results of a comparison between grid and slot technique regarding dose to the patient, scatter reduction, image quality and the effect of automatic exposure control are reported. (author)

Cusp-Gun Sixth-Harmonic Slotted Gyrotron

Science.gov (United States)

Stutzman, R. C.; McDermott, D. B.; Hirata Luhmann, Y., Jr.; Gallagher, D. A.; Spencer, T. A.

2000-10-01

A high-harmonic slotted gyrotron has been constructed at UC Davis to be driven by a 70 kV, 3.5 A, axis-encircling electron beam from a Northrop Grumman Cusp gun. The 94 GHz, slotted sixth-harmonic gyrotron is predicted to generate 50 kW with an efficiency of 20%. Using the profile of the adiabatic field reversal from the UC Davis superconducting test-magnet, EGUN simulations predict that an axis-encircling electron beam will be generated with an axial velocity spread of Δ v_z/v_z=10% for the desired velocity ratio of α =v_z/v_z=1.5. The design will also be presented for an 8th-harmonic W-band gyrotron whose magnetic field can be supplied by a lightweight permanent magnet.

Tri-Band CPW-Fed Stub-Loaded Slot Antenna Design for WLAN/WiMAX Applications

Science.gov (United States)

Li, Jianxing; Guo, Jianying; He, Bin; Zhang, Anxue; Liu, Qing Huo

2016-11-01

A novel uniplanar CPW-fed tri-band stub-loaded slot antenna is proposed for wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications. Dual resonant modes were effectively excited in the upper band by using two identical pairs of slot stubs and parasitic slots symmetrically along the arms of a traditional CPW-fed slot dipole, achieving a much wider bandwidth. The middle band was realized by the fundamental mode of the slot dipole. To obtain the lower band, two identical inverted-L-shaped open-ended slots were symmetrically etched in the ground plane. A prototype was fabricated and measured, showing that tri-band operation with 10-dB return loss bandwidths of 150 MHz from 2.375 to 2.525 GHz, 725 MHz from 3.075 to 3.8 GHz, and 1.9 GHz from 5.0 to 6.9 GHz has been achieved. Details of the antenna design as well as the measured and simulated results are presented and discussed.

EFFECTS OF SLOTTED BLADING ON SECONDARY FLOW IN HIGHLY LOADED COMPRESSOR CASCADE

Directory of Open Access Journals (Sweden)

RAMZI MDOUKI

2013-10-01

Full Text Available With the aim to increase allowable blade loadings and enlarge stable operating range in highly loaded compressor, this work is carried out in order to explore the potential of passive control via slotted bladings in linear cascade configurations under both design and stall conditions. Through an extensive 2D-numerical study, the effects of location, width and slope of slots were analysed and the best configuration was identified. Based on the optimal slot, the 3D aerodynamic performances of cascade were studied and the influence of slotted blading to control endwall flow was investigated. Both 2D and 3D calculations are performed on steady RANS solver with standard k-epsilon turbulence model and low Mach number regime. The total loss coefficient, turning angle and flow visualizations on the blade and end-wall surfaces are adopted to describe the different configurations. The obtained results show, for 2D situation, that a maximum of 28.3% reduction in loss coefficient had been reached and the flow turning was increased with approximately 5°. Concerning 3D flow fields the slots marked their benefit at large incoming flow angles which delays the separation on both end wall and blade suction surface at mid span. However, at design conditions, the slotted blades are not able to control secondary flows near the wall and so, lose their potential.

FLOW VISUALIZATION OF RECTANGULAR SLOT AIR JET IMPINGEMENT ON FLAT SURFACES

OpenAIRE

Satheesha V *1, B. K. Muralidhra2, Abhilash N3, C. K. Umesh4

2018-01-01

Jet impingement near the mid-chord of the gas turbine blade is treated as a flat plate. Experimental and numerical investigations are carried out for a single slot air jet impinging on flat surface for two different rectangular slots of dimension (3mm x 65 mm) and (5mm x 65 mm). Experimentation is done to study the flow pattern topography on the flat target plate, with varying the flow rate from 20 LPM to 50 LPM by varying the nozzle to plate distance from 9 mm to 24 mm for slot jet of 3mm an...

Small angle slot divertor concept for long pulse advanced tokamaks

Science.gov (United States)

Guo, H. Y.; Sang, C. F.; Stangeby, P. C.; Lao, L. L.; Taylor, T. S.; Thomas, D. M.

2017-04-01

SOLPS-EIRENE edge code analysis shows that a gas-tight slot divertor geometry with a small-angle (glancing-incidence) target, named the small angle slot (SAS) divertor, can achieve cold, dissipative/detached divertor conditions at relatively low values of plasma density at the outside midplane separatrix. SAS exhibits the following key features: (1) strong enhancement of the buildup of neutral density in a localized region near the plasma strike point on the divertor target; (2) spreading of the cooling front across the divertor target with the slot gradually flaring out from the strike point, thus effectively reducing both heat flux and erosion on the entire divertor target surface. Such a divertor may potentially provide a power and particle handling solution for long pulse advanced tokamaks.

FEM Analysis of Brushless DC Servomotor with Fractional Number of Slots per Pole

Directory of Open Access Journals (Sweden)

BALUTA, G.

2014-02-01

Full Text Available The authors present in this paper the analysis with Finite Element Method (FEM of the magnetic circuit for a Brushless DC servomotor with fractional number of slots/pole (9 slots and 10 poles. For this purpose, FEMM 4.2 software package was used for the analysis. To obtain the waveforms of Back-ElectroMotive Forces (BEMFs, electromagnetic and cogging torque for servomotor a program in LUA scripting language (integrated into interactive shell of FEMM4.2 has been created. A comparation with a structure with integer number of slots/pole (18 slots and 6 poles was also realized. The analysis results prove that the structure chosen is an optimal solution: sinusoidal waveforms of BEMFs, improved electromagnetic torque and reduced cogging torque. Therefore, the operating characteristics of the servomotor with 9/10 slots/poles manufactured by Sistem Euroteh Company and included in an integrated electrical drives system are presented in this paper.

Cogging Torque Reduction by Slot-Opening Shift for Permanent Magnet Machines

DEFF Research Database (Denmark)

Liu, Ting; Huang, Shoudao; Gao, Jian

2013-01-01

In this paper, an effective cogging torque reduction method based on shifting the slot-openings is presented. Stator teeth are divided into groups and proper slot-opening shift is applied for each group. The cogging torque can then be greatly reduced while the back-EMF waveforms remain symmetrical...

Hydraulic performance of a low specific speed centrifugal pump with Spanwise-Slotted Blades

International Nuclear Information System (INIS)

Ye, D X; Li, H; Wang, Y

2013-01-01

The hydraulic efficiency of a low specific speed centrifugal pump is low because of the long and narrow meridian flow passage, and the severe disk friction. Spanwise slotted blade flow control technology has been applied to the low specific speed centrifugal pump. This paper concluded that spanwise slotted blades can improve the pump performance in both experiments and simulations. In order to study the influence to the impeller and volute by spanwise slotted blade, impeller efficiency and volute efficiency were defined. The minimum volute efficiency and the maximum pump efficiency appear at the same time in the design flow condition in the unsteady simulation. The mechanism of spanwise slotted blade flow control technology should be researched furthermore

Realistic Free-Spins Features Increase Preference for Slot Machines.

Science.gov (United States)

Taylor, Lorance F; Macaskill, Anne C; Hunt, Maree J

2017-06-01

Despite increasing research into how the structural characteristics of slot machines influence gambling behaviour there have been no experimental investigations into the effect of free-spins bonus features-a structural characteristic that is commonly central to the design of slot machines. This series of three experiments investigated the free-spins feature using slot machine simulations to determine whether participants allocate more wagers to a machine with free spins, and, which components of free-spins features drive this preference. In each experiment, participants were exposed to two computer-simulated slot machines-one with a free-spins feature or similar bonus feature and one without. Participants then completed a testing phase where they could freely switch between the two machines. In Experiment 1, participants did not prefer the machine with a simple free-spins feature. In Experiment 2 the free-spins feature incorporated additional elements such as sounds, animations, and an increased win frequency; participants preferred to gamble on this machine. The Experiment 3 "bonus feature" machine resembled the free spins machine in Experiment 2 except spins were not free; participants showed a clear preference for this machine also. These findings indicate that (1) free-spins features have a major influence over machine choice and (2) the "freeness" of the free-spins bonus features is not an important driver of preference, contrary to self-report and interview research with gamblers.

14 CFR 93.226 - Allocation of slots in low-demand periods.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Allocation of slots in low-demand periods. 93.226 Section 93.226 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... low-demand periods. (a) If there are available slots in the following time periods and there are no...

Elevated CPW-Fed Slotted Microstrip Antenna for Ultra-Wideband Application

Directory of Open Access Journals (Sweden)

Chandan Kumar Ghosh

2012-01-01

Full Text Available Elevated-coplanar-waveguide- (ECPW- fed microstrip antenna with inverted “G” slots in the back conductor is presented. It is modeled and analyzed for the application of multiple frequency bands. The changes in radiation and the transmission characteristics are investigated by the introduction of the slots in two different positions at the ground plane (back conductor. The proposed antenna without slots exhibits a stop band from 2.55 GHz to 4.25 GHz while introducing two slots on the back conductor, two adjacent poles appear at central frequencies of 3.0 GHz and 3.9 GHz, respectively, and the antenna shows the ultra-wideband (UWB characteristics. The first pole appears at the central frequency of 3.0 GHz and covers the band width of 950 MHz, and the second pole exists at a central frequency of 3.90 GHz covering a bandwidth of 750 MHz. Experimental result shows that impedance bandwidth of 129% (S11<-10 dB is well achieved when the antenna is excited with both slots. Compared to most of the previously reported ECPW structures, the impedance bandwidth of this antenna is increased and also the size of the antenna becomes smaller and more suitable for many wireless applications like PCS (1850–1990 MHz, WLAN (2.4–2.484 GHz, WiMAX (2.5–2.69 GHz and 5.15–5.85 GHz, and also X-band communication.

Electro-optical logic gates based on graphene-silicon waveguides

Science.gov (United States)

Chen, Weiwei; Yang, Longzhi; Wang, Pengjun; Zhang, Yawei; Zhou, Liqiang; Yang, Tianjun; Wang, Yang; Yang, Jianyi

2016-08-01

In this paper, designs of electro-optical AND/NAND, OR/ NOR, XOR/XNOR logic gates based on cascaded silicon graphene switches and regular 2×1 multimode interference combiners are presented. Each switch consists of a Mach-Zehnder interferometer in which silicon slot waveguides embedded with graphene flakes are designed for phase shifters. High-speed switching function is achieved by applying an electrical signal to tune the Fermi levels of graphene flakes causing the variation of modal effective index. Calculation results show the crosstalk in the proposed optical switch is lower than -22.9 dB within a bandwidth from 1510 nm to 1600 nm. The designed six electro-optical logic gates with the operation speed of 10 Gbit/s have a minimum extinction ratio of 35.6 dB and a maximum insertion loss of 0.21 dB for transverse electric modes at 1.55 μm.

Numerical study on non-locally reacting behavior of nacelle liners incorporating drainage slots

Science.gov (United States)

Chen, Chao; Li, Xiaodong; Thiele, Frank

2018-06-01

For acoustic liners used in current commercial nacelles, in order to prevent any liquid accumulating in the resonators, drainage slots are incorporated on the partition walls between closely packed cavities. Recently, an experimental study conducted by Busse-Gerstengarbe et al. shown that the cell interaction introduced by drainage slots causes an additional dissipation peak which increases with the size of the slot. However, the variation of damping process due to drainage slots is still not fully understood. Therefore, a numerical study based on computational aeroacoustic methods is carried out to investigate the mechanism of the changed attenuation characteristics due to drainage slots in presence of grazing incident sound waves with low or high intensities. Different slot configurations are designed based on the generic non-locally reacting liner model adopted in the experimental investigation. Both 2-D and 3-D numerical simulations of only slit resonators are carried out. Numerical results indicate that the extra peak is a result of a resonance excited in the second cavity at specific frequency. Under high sound pressure level incoming waves, the basic characteristics of the acoustic performance remain. However, vortex shedding transpires at the resonances around both the slits and the drainage slot. Vorticity contours show that the connection of two coupled cavities decreases the strength of vortex shedding around the basic Helmholtz resonance due to a higher energy reflection. Meanwhile, the cell interaction significantly increases the vorticity magnitude near the extra resonant frequency. Finally, a semi-empirical model is derived to predict the extra attenuation peak frequency.

Slotted Photonic Crystal Sensors

Science.gov (United States)

Scullion, Mark G.; Krauss, Thomas F.; Di Falco, Andrea

2013-01-01

Optical biosensors are increasingly being considered for lab-on-a-chip applications due to their benefits such as small size, biocompatibility, passive behaviour and lack of the need for fluorescent labels. The light guiding mechanisms used by many of them results in poor overlap of the optical field with the target molecules, reducing the maximum sensitivity achievable. This review article presents a new platform for optical biosensors, namely slotted photonic crystals, which provide higher sensitivities due to their ability to confine, spatially and temporally, the optical mode peak within the analyte itself. Loss measurements showed values comparable to standard photonic crystals, confirming their ability to be used in real devices. A novel resonant coupler was designed, simulated, and experimentally tested, and was found to perform better than other solutions within the literature. Combining with cavities, microfluidics and biological functionalization allowed proof-of-principle demonstrations of protein binding to be carried out. Higher sensitivities were observed in smaller structures than possible with most competing devices reported in the literature. This body of work presents slotted photonic crystals as a realistic platform for complete on-chip biosensing; addressing key design, performance and application issues, whilst also opening up exciting new ideas for future study. PMID:23503295

Slotted Photonic Crystal Sensors

Directory of Open Access Journals (Sweden)

Andrea Di Falco

2013-03-01

Full Text Available Optical biosensors are increasingly being considered for lab-on-a-chip applications due to their benefits such as small size, biocompatibility, passive behaviour and lack of the need for fluorescent labels. The light guiding mechanisms used by many of them results in poor overlap of the optical field with the target molecules, reducing the maximum sensitivity achievable. This review article presents a new platform for optical biosensors, namely slotted photonic crystals, which provide higher sensitivities due to their ability to confine, spatially and temporally, the optical mode peak within the analyte itself. Loss measurements showed values comparable to standard photonic crystals, confirming their ability to be used in real devices. A novel resonant coupler was designed, simulated, and experimentally tested, and was found to perform better than other solutions within the literature. Combining with cavities, microfluidics and biological functionalization allowed proof-of-principle demonstrations of protein binding to be carried out. Higher sensitivities were observed in smaller structures than possible with most competing devices reported in the literature. This body of work presents slotted photonic crystals as a realistic platform for complete on-chip biosensing; addressing key design, performance and application issues, whilst also opening up exciting new ideas for future study.

Low profile frequency agile MIMO slot antenna with TCM characterization

KAUST Repository

Ghalib, Asim

2017-06-07

In this paper, a frequency reconfigurable multiple-input-multiple-output (MIMO) slot antenna is presented. The proposed design is low profile and compact with wide tunability range, covering several well-known frequency bands from 1800 MHz to 2450 MHz. The frequency reconfigurability is achieved by loading the annular slot with varactor diodes. The antenna system is also analyzed for MIMO performance metrics. Moreover, the effect of circular slot antenna on the chassis modes is also investigated using the theory of characteristic modes (TCM). The physical principle behind frequency reconfigurability is also investigated using TCM analysis. An interesting finding is observed using varactor diodes for frequency reconfigurability, that is the reactive impedance loading does not alter the modal significance (MS) plots but only aid in the input impedance matching at different frequency bands.

Wideband Circularly Polarized Printed Ring Slot Antenna for 5 GHz – 6 GHz

Science.gov (United States)

Nasrun Osman, Mohamed; Rahim, Mohamad Helmi A.; Jusoh, Muzammil; Sabapathy, Thennarasan; Rahim, Mohamad Kamal A.; Norlyana Azemi, Saidatul

2018-03-01

This paper presents the design of circularly polarized printed slot antenna operating at 5 – 6 GHz. The proposed antenna consists of L-shaped feedline on the top of structure and circular ring slot positioned at the ground plane underneath the substrate as a radiator. A radial and narrow slot in the ground plane provides coupling between the L-shaped feedline and circular ring slot. The circular polarization is realized by implementing the slits perturbation located diagonally to perturb the current flow on the slot structure. The antenna prototype is fabricated on FR4 substrate. The simulated and measured results are compared and analyzed to demonstrate the performance of the antenna. Good measured of simulated results are obtained at the targeted operating frequency. The simulated -10dB reflection coefficient bandwidths and axial ratio are 750 MHz and 165 MHz, respectively. The investigation on the affect of the important parameters towards the reflection coefficient and axial are also presented. The proposed antenna is highly potential to be used for wireless local area network (WLAN) and wireless power transfer (WPT).

Modeling arbitrarily directed slots that are narrow both in width and depth with regard to the FDTD spatial cell

Energy Technology Data Exchange (ETDEWEB)

Riley, D.J.; Turner, C.D.

1991-12-31

The Hybrid Thin-Slot Algorithm (HTSA) integrates a transient integral-equation solution for an aperture in an infinite plane into a finite-difference time-domain (FDTD) code. The technique was introduced for linear apertures and was extended to include wall loss and lossy internal gaskets. A general implementation for arbitrary thin slots is briefly described here. The 3-D FDTD-code TSAR was selected for the implementation. The HTSA does not provide universal solutions to the narrow slot problem, but has merits appropriate for particular applications. The HTSA is restricted to planar slots, but can solve the important case that both the width and depth of the slot are narrow compared to the FDTD spatial cell. IN addition, the HTSA is not bound to the FDTD discrete spatial and time increments, and therefore, high-resolution solutions for the slot physics are possible. The implementation of the HTSA into TSAR is based upon a ``slot data file`` that includes the cell indices where the desired slots are exist within the FDTD mesh. For an HTSA-defined slot, the wall region local to the slot is shorted, and therefore, to change the slot`s topology simply requires altering the file to include the desired cells. 7 refs.

Analysis of the crystalline characteristics of nc-Si:H thin film using a hyperthermal neutral beam generated by an inclined slot-excited antenna

Energy Technology Data Exchange (ETDEWEB)

Park, Jong-Bae; Kim, Young-Woo; Kim, Dae Chul; Kim, Jongsik; Hong, Seung Pyo; Yoo, Suk Jae; Oh, Kyoung Suk, E-mail: ksoh@nfri.re.kr

2013-11-29

The deposition of hydrogenated nano-crystal silicon (nc-Si:H) thin film for manufacturing quantum dot solar cells, which has received attention due to the use of this film third-generation solar cells, is studied here. A hyperthermal neutral beam (HNB) generated by an inclined slot-excited antenna plasma source is used to reduce damage to the silicon thin film and deposition of the crystalline thin film is carried out on a substrate at a low temperature (< 200 °C). The size and the crystalline fraction of the nc-Si:H of the deposited thin film were analyzed by scanning transmission electron microscopy and a Raman microscope. As a result, silicon crystals 1–10 nm in size were observed in the amorphous silicon matrix. According to previous studies, the size and the crystalline fraction of nc-Si:H in deposited thin films increase as the hydrogen flow rate is increased. However, the increment of hydrogen flow rate decreases the deposition rate rapidly. The size and the crystalline fraction of nc-Si:H are adjustable by varying the substrate temperature and HNB energy without a change of the hydrogen flow rate. There are optimum conditions between the HNB energy and the substrate temperature for an appropriate amount of nc-Si:H in silicon thin film. - Highlights: • The appropriate hyperthermal neutral beam energy seems to assist film formation. • The Si crystal size can be adjusted by varying hyperthermal neutral beam energy. • The nc-Si:H 1 ∼ 10 in nm size was observed in the amorphous silicon matrix.

ATLAS Cold Leg Top Slot Break Analysis using RELAP5

Energy Technology Data Exchange (ETDEWEB)

Sung, Haejung; Lee, Sang Ik; Park, Ju-Hyun; Choi, Tong-Soo [KEPCO NF, Daejeon (Korea, Republic of)

2016-10-15

U.S. Nuclear Regulatory Commission (US-NRC) has been reviewing the design certification application for APR1400 submitted by Korea Electric Power Corporation (KEPCO). The main concern about cold leg top slot break is that cladding temperature might be increased by core uncover due to four loop seal reformation following flooding of safety injection water. An integral effect test for cold leg top slot break was performed by KAERI (Korea Atomic Energy Research Institute) using ATLAS (Advanced Thermal-Hydraulic Test Loop for Accident Simulation), which is a scaled down experimental facility for APR1400. In this study, RELAP5/MOD3.3/Patch04 is assessed by experimental result of ATLAS cold leg top slot break. Also, thermal hydraulic phenomena by four loop seals reformation is observed by RELAP5 result. The RELAP5/MOD3.3/Patch04 is assessed by the experimental result of ATLAS cold leg top slot break. The top slot break is described by offtake model, and the mass flow rate is fairly well estimated. The RELAP5 well predicts the correlation between general trend and four loop seal reformation. The pressure of the core region and the cladding temperature tends to increase during four loop seal reformation due to steam path blockage on four loop seals. It is presumed that the code cannot estimate two phase phenomena by loop seal clearing as same as experiments. In terms of cladding temperature, loop seal reformation due to loop seal elevation of APR1400 does not need to be the issue, since the void fraction at the active top core is maintained over 0.4.

Fleet Planning Decision-Making: Two-Stage Optimization with Slot Purchase

Directory of Open Access Journals (Sweden)

Lay Eng Teoh

2016-01-01

Full Text Available Essentially, strategic fleet planning is vital for airlines to yield a higher profit margin while providing a desired service frequency to meet stochastic demand. In contrast to most studies that did not consider slot purchase which would affect the service frequency determination of airlines, this paper proposes a novel approach to solve the fleet planning problem subject to various operational constraints. A two-stage fleet planning model is formulated in which the first stage selects the individual operating route that requires slot purchase for network expansions while the second stage, in the form of probabilistic dynamic programming model, determines the quantity and type of aircraft (with the corresponding service frequency to meet the demand profitably. By analyzing an illustrative case study (with 38 international routes, the results show that the incorporation of slot purchase in fleet planning is beneficial to airlines in achieving economic and social sustainability. The developed model is practically viable for airlines not only to provide a better service quality (via a higher service frequency to meet more demand but also to obtain a higher revenue and profit margin, by making an optimal slot purchase and fleet planning decision throughout the long-term planning horizon.

Extremely High-Birefringent Asymmetric Slotted-Core Photonic Crystal Fiber in THz Regime

DEFF Research Database (Denmark)

Islam, Raonaqul; Habib, Selim; Hasanuzzaman, G.K.M.

2015-01-01

We present a thorough numerical analysis of a highly birefringent slotted porous-core circular photonic crystal fiber (PCF) for terahertz (THz) wave guidance. The slot shaped air-holes break the symmetry of the porous-core which offers a very high birefringence whereas the compact geometry of the...

Metal membrane with dimer slots as a universal polarizer

DEFF Research Database (Denmark)

Zhukovsky, Sergei; Zalkovskij, Maksim; Malureanu, Radu

2014-01-01

In this work, we show theoretically and confirm experimentally that thin metal membranes patterned with an array of slot dimers (or their Babinet analogue with metal rods) can function as a versatile spectral and polarization filter. We present a detailed covariant multipole theory for the electr......In this work, we show theoretically and confirm experimentally that thin metal membranes patterned with an array of slot dimers (or their Babinet analogue with metal rods) can function as a versatile spectral and polarization filter. We present a detailed covariant multipole theory...

14 CFR 93.218 - Slots for transborder service to and from Canada.

Science.gov (United States)

2010-01-01

... Canada. 93.218 Section 93.218 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... service to and from Canada. (a) Except as otherwise provided in this subpart, international slots...'Hare in the Winter season. (c) Any modification to the slot base by the Government of Canada or the...

A piezoelectric ultrasonic linear micromotor using a slotted stator.

Science.gov (United States)

Yun, Cheol-Ho; Watson, Brett; Friend, James; Yeo, Leslie

2010-08-01

A novel ultrasonic micro linear motor that uses 1st longitudinal and 2nd bending modes, derived from a bartype stator with a rectangular slot cut through the stator length, has been proposed and designed for end-effect devices of microrobotics and bio-medical applications. The slot structure plays an important role in the motor design, and can be used not only to tune the resonance frequency of the two vibration modes but also to reduce the undesirable longitudinal coupling displacement caused by bending vibration at the end of the stator. By using finite element analysis, the optimal slot dimension to improve the driving tip motion was determined, resulting in the improvement of the motor performance. The trial linear motor, with a weight of 1.6 g, gave a maximum driving velocity of 1.12 m/s and a maximum driving force of 3.4 N. A maximum mechanical output power of 1.1 W was obtained at force of 1.63 N and velocity of 0.68 m/s. The output mechanical power per unit weight was 688 W/kg.

Seawave Slot-Cone Generator

DEFF Research Database (Denmark)

Vicinanza, Diego; Margheritini, Lucia; Contestabile, Pasquale

2009-01-01

This paper discusses a new type of Wave Energy Converter (WEC) named Seawave Slot-Cone Generator (SSG). The SSG is a WEC of the overtopping type. The structure consists of a number of reservoirs one on the top of each others above the mean water level in which the water of incoming waves is store...... on sloping walls constituting the structure. The research is intended to be of direct use to engineers analyzing design and stability of this peculiar kind of coastal structure....

Ka-Band Slot-Microstrip-Covered and Waveguide-Cavity-Backed Monopulse Antenna Array

Directory of Open Access Journals (Sweden)

Li-Ming Si

2014-01-01

Full Text Available A slot-microstrip-covered and waveguide-cavity-backed monopulse antenna array is proposed for high-resolution tracking applications at Ka-band. The monopulse antenna array is designed with a microstrip with 2×32 slots, a waveguide cavity, and a waveguide monopulse comparator, to make the structure simple, reduce the feeding network loss, and increase the frequency bandwidth. The 2×32 slot-microstrip elements are formed by a metal clad dielectric substrate and slots etched in the metal using the standard printed circuit board (PCB process with dimensions of 230 mm  ×  10 mm. The proposed monopulse antenna array not only maintains the advantages of the traditional waveguide slot antenna array, but also has the characteristics of wide bandwidth, high consistence, easy of fabrication, and low cost. From the measured results, it exhibits good monopulse characteristics, including the following: the maximum gains of sum pattern are greater than 24 dB, the 3 dB beamwidth of sum pattern is about 2.2 degrees, the sidelobe levels of the sum pattern are less than −18 dB, and the null depths of the difference pattern are less than −25 dB within the operating bandwidth between 33.65 GHz and 34.35 GHz for VSWR ≤ 2.

Enhancement of acousto-optical coupling in two-dimensional air-slot phoxonic crystal cavities by utilizing surface acoustic waves

Energy Technology Data Exchange (ETDEWEB)

Ma, Tian-Xue [Institute of Engineering Mechanics, Beijing Jiaotong University, Beijing 100044 (China); Wang, Yue-Sheng, E-mail: yswang@bjtu.edu.cn [Institute of Engineering Mechanics, Beijing Jiaotong University, Beijing 100044 (China); Zhang, Chuanzeng [Department of Civil Engineering, University of Siegen, D-57068 Siegen (Germany)

2017-01-30

A phoxonic crystal is a periodically patterned material that can simultaneously localize optical and acoustic modes. The acousto-optical coupling in two-dimensional air-slot phoxonic crystal cavities is investigated numerically. The photons can be well confined in the slot owing to the large electric field discontinuity at the air/dielectric interfaces. Besides, the surface acoustic modes lead to the localization of the phonons near the air-slot. The high overlap of the photonic and phononic cavity modes near the slot results in a significant enhancement of the moving interface effect, and thus strengthens the total acousto-optical interaction. The results of two cavities with different slot widths show that the coupling strength is dependent on the slot width. It is expected to achieve a strong acousto-optical/optomechanical coupling in air-slot phoxonic crystal structures by utilizing surface acoustic modes. - Highlights: • Two-dimensional air-slot phoxonic crystal cavities which can confine simultaneously optical and acoustic waves are proposed. • The acoustic and optical waves are highly confined near/in the air-slot. • The high overlap of the photonic and phononic cavity modes significantly enhances the moving interface effect. • Different factors which affect the acousto-optical coupling are discussed.

Detailed Study of Closed Stator Slots for a Direct-Driven Synchronous Permanent Magnet Linear Wave Energy Converter

Directory of Open Access Journals (Sweden)

Erik Lejerskog

2014-01-01

Full Text Available The aim of this paper is to analyze how a permanent magnet linear generator for wave power behaves when the stator slots are closed. The usual design of stator geometry is to use open slots to maintain a low magnetic leakage flux between the stator teeth. By doing this, harmonics are induced in the magnetic flux density in the air-gap due to slotting. The closed slots are designed to cause saturation, to keep the permeability low. This reduces the slot harmonics in the magnetic flux density, but will also increase the flux leakage between the stator teeth. An analytical model has been created to study the flux through the closed slots and the result compared with finite element simulations. The outcome shows a reduction of the cogging force and a reduction of the harmonics of the magnetic flux density in the air-gap. It also shows a small increase of the total magnetic flux entering the stator and an increased magnetic flux leakage through the closed slots.

Effect of Slotted Anode on Gas Bubble Behaviors in Aluminum Reduction Cell

Science.gov (United States)

Sun, Meijia; Li, Baokuan; Li, Linmin; Wang, Qiang; Peng, Jianping; Wang, Yaowu; Cheung, Sherman C. P.

2017-12-01

In the aluminum reduction cells, gas bubbles are generated at the bottom of the anode which eventually reduces the effective current contact area and the system efficiency. To encourage the removal of gas bubbles, slotted anode has been proposed and increasingly adopted by some industrial aluminum reduction cells. Nonetheless, the exact gas bubble removal mechanisms are yet to be fully understood. A three-dimensional (3D) transient, multiphase flow mathematical model coupled with magnetohydrodynamics has been developed to investigate the effect of slotted anode on the gas bubble movement. The Eulerian volume of fluid approach is applied to track the electrolyte (bath)-molten aluminum (metal) interface. Meanwhile, the Lagrangian discrete particle model is employed to handle the dynamics of gas bubbles with considerations of the buoyancy force, drag force, virtual mass force, and pressure gradient force. The gas bubble coalescence process is also taken into account based on the O'Rourke's algorithm. The two-way coupling between discrete bubbles and fluids is achieved by the inter-phase momentum exchange. Numerical predictions are validated against the anode current variation in an industrial test. Comparing the results using slotted anode with the traditional one, the time-averaged gas bubble removal rate increases from 36 to 63 pct; confirming that the slotted anode provides more escaping ways and shortens the trajectories for gas bubbles. Furthermore, the slotted anode also reduces gas bubble's residence time and the probability of coalescence. Moreover, the bubble layer thickness in aluminum cell with slotted anode is reduced about 3.5 mm (17.4 pct), so the resistance can be cut down for the sake of energy saving and the metal surface fluctuation amplitude is significantly reduced for the stable operation due to the slighter perturbation with smaller bubbles.

Benefits and unexpected artifacts of biplanar digital slot-scanning imaging in children

Energy Technology Data Exchange (ETDEWEB)

Blumer, Steven L. [Nemours/A.I duPont Hospital for Children, Department of Medical Imaging, Wilmington, DE (United States); Dinan, David [Nemours Children' s Hospital, Orlando, FL (United States); Grissom, Leslie E. [Nemours/Alfred I. duPont Hospital for Children, Department of Radiology, Wilmington, DE (United States)

2014-07-15

Biplanar digital slot-scanning allows for relatively low-dose orthopedic imaging, an advantage in imaging children given the growing concerns regarding radiosensitivity. We have used this system for approximately 1 year for orthopedic imaging of the spine and lower extremities. We have noted advantages of using the digital slot-scanning system when compared with computed radiographic and standard digital radiographic imaging systems, but we also found unexpected but common imaging artifacts that are the direct result of the imaging method and that have not been reported. This pictorial essay serves to familiarize radiologists with the advantages of the digital slot-scanning system as well as imaging artifacts common with this new technology. (orig.)

A novel non-sequential hydrogen-pulsed deep reactive ion etching of silicon

International Nuclear Information System (INIS)

Gharooni, M; Mohajerzadeh, A; Sandoughsaz, A; Khanof, S; Mohajerzadeh, S; Asl-Soleimani, E

2013-01-01

A non-sequential pulsed-mode deep reactive ion etching of silicon is reported that employs continuous etching and passivation based on SF 6 and H 2 gases. The passivation layer, as an important step for deep vertical etching of silicon, is feasible by hydrogen pulses in proper time-slots. By adjusting the etching parameters such as plasma power, H 2 and SF 6 flows and hydrogen pulse timing, the process can be controlled for minimum underetch and high etch-rate at the same time. High-aspect-ratio features can be realized with low-density plasma power and by controlling the reaction chemistry. The so-called reactive ion etching lag has been minimized by operating the reactor at higher pressures. X-ray photoelectron spectroscopy and scanning electron microscopy have been used to study the formation of the passivation layer and the passivation mechanism. (paper)

A strained silicon cold electron bolometer using Schottky contacts

Energy Technology Data Exchange (ETDEWEB)

Brien, T. L. R., E-mail: tom.brien@astro.cf.ac.uk; Ade, P. A. R.; Barry, P. S.; Dunscombe, C.; Morozov, D. V.; Sudiwala, R. V. [School of Physics and Astronomy, Cardiff University, Queen' s Buildings, The Parade, Cardiff CF24 3AA (United Kingdom); Leadley, D. R.; Myronov, M.; Parker, E. H. C.; Prest, M. J.; Whall, T. E. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Prunnila, M. [VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT Espoo (Finland); Mauskopf, P. D. [School of Physics and Astronomy, Cardiff University, Queen' s Buildings, The Parade, Cardiff CF24 3AA (United Kingdom); Department of Physics and School of Earth and Space Exploration, Arizona State University, 650 E. Tyler Mall, Tempe, Arizona 85287 (United States)

2014-07-28

We describe optical characterisation of a strained silicon cold electron bolometer (CEB), operating on a 350 mK stage, designed for absorption of millimetre-wave radiation. The silicon cold electron bolometer utilises Schottky contacts between a superconductor and an n{sup ++} doped silicon island to detect changes in the temperature of the charge carriers in the silicon, due to variations in absorbed radiation. By using strained silicon as the absorber, we decrease the electron-phonon coupling in the device and increase the responsivity to incoming power. The strained silicon absorber is coupled to a planar aluminium twin-slot antenna designed to couple to 160 GHz and that serves as the superconducting contacts. From the measured optical responsivity and spectral response, we calculate a maximum optical efficiency of 50% for radiation coupled into the device by the planar antenna and an overall noise equivalent power, referred to absorbed optical power, of 1.1×10{sup −16} W Hz{sup −1/2} when the detector is observing a 300 K source through a 4 K throughput limiting aperture. Even though this optical system is not optimized, we measure a system noise equivalent temperature difference of 6 mK Hz{sup −1/2}. We measure the noise of the device using a cross-correlation of time stream data, measured simultaneously with two junction field-effect transistor amplifiers, with a base correlated noise level of 300 pV Hz{sup −1/2} and find that the total noise is consistent with a combination of photon noise, current shot noise, and electron-phonon thermal noise.

Joint slot allocation and dynamic pricing of container sea–rail multimodal transportation

Directory of Open Access Journals (Sweden)

Di Liu

2015-06-01

Full Text Available The container sea–rail multimodal transport system faces complex challenges with demand uncertainties for joint slot allocation and dynamic pricing. The challenge is formulated as a two-stage optimal model based on revenue management (RM as actual slots sale of multi-node container sea–rail multimodal transport usually includes contract sale to large shippers and free sale to scattered shippers. First stage in the model utilizes an origin-destination control approach, formulated as a stochastic integer programming equation, to settle long-term slot allocation in the contract market and empty container allocation. Second stage in the model is formulated as a stochastic nonlinear programming equation to solve a multiproduct joint dynamic pricing and inventory control problem for price settling and slot allocation in each period of free market. Considering the random nature of demand, the methods of chance constrained programming and robust optimization are utilized to transform stochastic models into deterministic models. A numerical experiment is presented to verify the availability of models and solving methods. Results of considering uncertain/certain demand are compared, which show that the two-stage optimal strategy integrating slot allocation with dynamic pricing considering random demand is revealed to increase the revenue for multimodal transport operators (MTO while concurrently satisfying shippers' demand. Research resulting from this paper will contribute to the theory and practice of container sea–rail multimodal transport revenue management and provide a scientific decision-making tool for MTO.

Impedance of a slotted-pipe kicker

Energy Technology Data Exchange (ETDEWEB)

Zhou, Feng [Academia Sinica, Beijing, BJ (China). Inst. of High Energy Physics

1996-08-01

This paper introduces the principle of a new slotted kicker simply, which is made by using vacuum pipe itself with proper slits as current conductors, and then, presents a rough estimation of its longitudinal and transverse impedance, respectively. Calculation shows that its impedance is reduced significantly compared to our present air-coil kicker. (author)

A fast semi-analytical model for the slotted structure of induction motors with 36/28 stator/rotor slot combination

NARCIS (Netherlands)

Sprangers, R.L.J.; Paulides, J.J.H.; Gysen, B.L.J.; Lomonova, E.A.

2014-01-01

A fast, semi-analyticalmodel for inductionmotors (IMs) with 36/28 stator/rotor slot combination is presented. In comparison to traditional analytical models for IMs, such as lumped parameter, magnetic equivalent circuit and anisotropic layer models, the presented model calculates a continuous

Analytical study of optimal design and gain parameters of double-slot plasmonic waveguides

International Nuclear Information System (INIS)

Handapangoda, Dayan; Rukhlenko, Ivan D; Premaratne, Malin

2013-01-01

We theoretically analyze guided modes in optically active and passive double-slot plasmonic waveguides. We show that for one of the two different mode symmetries supported by the waveguide, a most productive guiding condition can be realized by adjusting the thicknesses of the layers to optimal values. We also derive approximate analytic expressions to calculate the optimal geometrical parameters of the waveguide. Interestingly, our analysis shows that the propagation losses associated with the inverse mode symmetry of the double-slot waveguide are comparatively low, regardless of the dimensions of the waveguide. We further show that the propagation losses become the smallest in the limiting case of a single-slot (metal–dielectric–metal (MDM)) waveguide. For both double- and single-slot waveguides, we show that the gain required to overcome the losses can be reduced by choosing a dielectric with a low refractive index. We also derive accurate analytical expressions to readily estimate the critical gain and modal gain of the waveguides. (paper)

Vertical Slot Convection: A linear study

International Nuclear Information System (INIS)

McAllister, A.; Steinolfson, R.; Tajima, T.

1992-11-01

The linear stability properties of fluid convection in a vertical slot were studied. We use a Fourier-Chebychev decomposition was used to set up the linear eigenvalue problems for the Vertical Slot Convection and Benard problems. The eigenvalues, neutral stability curves, and critical point values of the Grashof number, G, and the wavenumber were determined. Plots of the real and imaginary parts of the eigenvalues as functions of G and α are given for a wide range of the Prandtl number, Pr, and special note is made of the complex mode that becomes linearly unstable above Pr ∼ 12.5. A discussion comparing different special cases facilitates the physical understanding of the VSC equations, especially the interaction of the shear-flow and buoyancy induced physics. Making use of the real and imaginary eigenvalues and the phase properties of the eigenmodes, the eigenmodes were characterized. One finds that the mode structure becomes progressively simpler with increasing Pr, with the greatest complexity in the mid ranges where the terms in the heat equation are of roughly the same size

Examination report: Remote video examination of air slots under the primary tank at 241-AN-107

International Nuclear Information System (INIS)

Pedersen, L.T.

1998-01-01

This report documents the results of remote video examination of air slots in the insulating concrete slab beneath the primary tank at 241-AN-107. Life Extension Equipment Engineering has selected tank 241-AN-107 for ultrasonic evaluation of tank wall, knuckle, and floor plates. Access to the primary tank floor plates is via the air slots which were formed into the insulating concrete slab during tank construction (reference drawings H-2-71105 and H-2-71160). Prior to deployment of the ultrasonic inspection equipment it is desirable to examine the air slots for obstructions and debris which could impede the ultrasonic equipment. The criteria, equipment description, deliverables, and responsibilities for examination of the air slots are described in HNF-1949, Rev. 0, ''Engineering Task Plan for Remote Video Examination of Air Slots Under the Primary Tank at 241-AN-107''

Incorporation of the stress concentration slots into the flexures for a high-performance microaccelerometer

International Nuclear Information System (INIS)

Zhao Yulong; Sun Lu; Liu Yan; Wang Weizhong; Tian Bian

2012-01-01

Presented in this paper is a development of a high-performance piezoresistive microaccelerometer based on the slot etching in the quad flexures for the vibration detection of high speed spindle. The proposed structure consists of a proof mass supported by four thin flexures with slots etched in the middle. Boron diffused piezoresistors located near the stress concentration regions are used for sensing the localized stress resulting from the incorporation of the slots into the flexures. Theoretical analysis and finite element analysis show satisfactory results of an improved sensitivity and favorable natural frequency higher than 10 kHz, conforming to the initial design requirements. The microfabrication techniques are described to prototype the two accelerometer chips, one with slots and the other one without slots. The tested microaccelerometers with 3 V DC power supply show an average sensitivity of 0.424 mV/g normal to the proof mass plane, increased by 60.6% than the ones without slots. An average transverse sensitivity is found to be 9.2 μV/g along X axis and 14.2 μV/g along Y axis, either of which is less than 3.5% of prime-axis sensitivity. Concerning the resonant frequency, dynamic experiment shows about 12.46 kHz and is available for the proposed design with a tiny loss of 3.5% compared with the quad-beam design. When taking the product of sensitivity and natural frequency as judgment criteria, an inspiring increase by 28.6% of the figure of merit is accomplished for the proposed accelerometer. Overall, the findings of this study confirm the feasibility of incorporating slots into the conventional configurations to improve the sensor sensitivity while maintaining a comparatively high natural frequency.

A numerical investigation on the effects of slot geometry on shock boundary layer interaction

Energy Technology Data Exchange (ETDEWEB)

Bazazzadeh, M.; Menshadi, M. D.; Karbasizadeh, M. [Dept. of Mechanical and Aerospace Engineering, Malek Ashtar University of Technology, Esfahan (Turkmenistan)

2017-01-15

Slot is one of the features that control Shock wave-boundary layer interaction (SBLI), which is generally used to prevent strong interference from shockwaves to the boundary layer in supersonic flows. With this feature, the height of the triple point of λ shock significantly increases, and this increase causes a decline in shock power and pressure drop rate. In the current paper, the main focus is on the monitoring of the geometrical effect of slot as an influential parameter on the structure of the shock and flow characteristics by using numerical methods. Therefore, the averaged implicit Navier-Stokes equations and two equation standard k-ω turbulence models for the numerical simulation of the flow field have been used. Results indicate that the numerical results are fairly consistent with the experimental data. Because of the increase in the number of slots (n), and the leading leg of the λ shock is located within the slot, the height of the triple point increases. However, because of the increasing drops due to viscosity, the total pressure changes are negligible. In addition, with an increase in this parameter, changes in the static pressure caused by the leading leg of the shock have increased. By increasing the width of the slots, the height of the triple point has had an upward trend up to s = 8 mm and then had nearly constant values. In this mode, the static pressure changes resulting from the leading leg of the shock are negligible. For increasing the number or the width of slots, the re-expansion waves formed within the slot are removed because of the reduction in the severity of the changes in the boundary layer. To simulate and compare the results with the data obtained from the experimental tests, results from the Cambridge University's wind tunnel tests have been used.

Airflow and Heat Transfer in the Slot-Vented Room with Radiant Floor Heating Unit

Directory of Open Access Journals (Sweden)

Xiang-Long Liu

2012-01-01

Full Text Available Radiant floor heating has received increasing attention due to its diverse advantages, especially the energy saving as compared to the conventional dwelling heating system. This paper presents a numerical investigation of airflow and heat transfer in the slot-vented room with the radiant floor heating unit. Combination of fluid convection and thermal radiation has been implemented through the thermal boundary conditions. Spatial distributions of indoor air temperature and velocity, as well as the heat transfer rates along the radiant floor and the outer wall, have been presented and analyzed covering the domains from complete natural convection to forced convection dominated flows. The numerical results demonstrate that the levels of average temperature in the room with lateral slot-ventilation are higher than those without slot-ventilation, but lower than those in the room with ceiling slot-ventilation. Overall, the slot-ventilation room with radiant floor heating unit could offer better indoor air quality through increasing the indoor air temperature and fresh air exchanging rate simultaneously. Concerning the airborne pollutant transports and moisture condensations, the performance of radiant floor heating unit will be further optimized in our future researches.

Slotted coax as a beam electrode

International Nuclear Information System (INIS)

Lambertson, G.R.; Kim, K.J.; Voelker, F.V.

1983-03-01

The slot coupled TEM line has been employed at CERN as a pick up electrode in the GHz range. It is a compact and broad band device, and will be quite attractive if the coupling efficiency is competitive with an array of quarter wave loops. In this paper, we study various properties of such a structure

Stall inception and warning in a single-stage transonic axial compressor with axial skewed slot casing treatment

International Nuclear Information System (INIS)

Lim, Byeung Jun; Kwon, Se Jin; Park, Tae Choon

2014-01-01

Characteristic changes in the stall inception in a single-stage transonic axial compressor with an axial skewed slot casing treatment were investigated experimentally. A rotating stall occurred intermittently in a compressor with an axial skewed slot, whereas spike-type rotating stalls occurred in the case of smooth casing. The axial skewed slot suppressed stall cell growth and increased the operating range. A mild surge, the frequency of which is the Helmholtz frequency of the compressor system, occurred with the rotating stall. The irregularity in the pressure signals at the slot bottom increased decreasing flow rate. An autocorrelation-based stall warning method was applied to the measured pressure signals. Results estimate and warn against the stall margin in a compressor with an axial skewed slot.

PIV study of large-scale flow organisation in slot jets

International Nuclear Information System (INIS)

Shestakov, Maxim V.; Dulin, Vladimir M.; Tokarev, Mikhail P.; Sikovsky, Dmitrii Ph.; Markovich, Dmitriy M.

2015-01-01

Highlights: • Volumetric velocity measurements are perfumed by PIV to analyse 3D flow organisation in a slot jet. • Proper orthogonal decomposition is used to extract coherent flow motion. • Movement of quasi-two-dimensional large-scale vortices is associated with jet meandering. • Amplitude of jet meandering is found to be aperiodically modulated. • Secondary longitudinal vortex rolls are important for cross-stream mixing and momentum transfer. - Abstract: The paper reports on particle image velocimetry (PIV) measurements in turbulent slot jets bounded by two solid walls with the separation distance smaller than the jet width (5–40%). In the far-field such jets are known to manifest features of quasi-two dimensional, two component turbulence. Stereoscopic and tomographic PIV systems were used to analyse local flows. Proper orthogonal decomposition (POD) was applied to extract coherent modes of the velocity fluctuations. The measurements were performed both in the initial region close to the nozzle exit and in the far fields of the developed turbulent slot jets for Re ⩾ 10,000. A POD analysis in the initial region indicates a correlation between quasi-2D vortices rolled-up in the shear layer and local flows in cross-stream planes. While the near-field turbulence shows full 3D features, the wall-normal velocity fluctuations day out gradually due to strong wall-damping resulting in an almost two-component turbulence. On the other hand, the longitudinal vortex rolls take over to act as the main agents in wall-normal and spanwise mixing and momentum transfer. The quantitative analysis indicates that the jet meandering amplitude was aperiodically modulated when arrangement of the large-scale quasi-2D vortices changed between asymmetric and symmetric pattern relatively to the jet axis. The paper shows that the dynamics of turbulent slot jets are more complex than those of 2D, plane and rectangular 3D jets. In particular, the detected secondary longitudinal

Semi-automatic parking slot marking recognition for intelligent parking assist systems

Directory of Open Access Journals (Sweden)

Ho Gi Jung

2014-01-01

Full Text Available This paper proposes a semi-automatic parking slot marking-based target position designation method for parking assist systems in cases where the parking slot markings are of a rectangular type, and its efficient implementation for real-time operation. After the driver observes a rearview image captured by a rearward camera installed at the rear of the vehicle through a touchscreen-based human machine interface, a target parking position is designated by touching the inside of a parking slot. To ensure the proposed method operates in real-time in an embedded environment, access of the bird's-eye view image is made efficient: image-wise batch transformation is replaced with pixel-wise instantaneous transformation. The proposed method showed a 95.5% recognition rate in 378 test cases with 63 test images. Additionally, experiments confirmed that the pixel-wise instantaneous transformation reduced execution time by 92%.

[The characteristics of and social support for pathological gamblers among "pachinko" or "slot" users in Japan].

Science.gov (United States)

Kumagami, Takashi

2014-01-01

In Japan, there are one to two million people suspected of being pathological gamblers according to the definition in DSM-IV-TR. Almost all of them use "pachinko" or "slot," which are gambling stores, throughout Japan, that number 12,000 in total. However, the characteristics and ratio of pathological "pachinko" and "slot" gamblers have not been investigated. The author aimed to determine the characteristics, ratio, and social support available for these users. The author administered an internet survey for users of "pachinko" or "slot." Two hundred and fifty users visited "pachinko" or "slot" stores more than twice a week, and 250 users visited once a week or once a month. The Japanese version of the South Oaks Gambling Screen was administered, and gamblers were asked about their awareness of pathological gambling and the condition of their social support. The author observed that 70.2% of "pachinko" or "slot" users were suspected pathological gamblers and 28.6% of "pachinko" or "slot" users were severe gamblers. A total of 39.3% of them were aware of their pathological gambling, and 6.5% of users who had awareness of pathological gambling had social support. However, most of their social support consisted of family and friends, and almost none of them attended psychiatric clinics, community health centers, or self-help groups like gamblers anonymous. Almost all "pachinko" or "slot" users were suspected of being pathological or severe gamblers. However, they did not approach psychiatric facilities or self-help groups. The author strongly recommends the need for educational programs in junior or high school to prevent future pathological gambling, and create awareness of the dangers of pathological gambling through TV commercials and "pachinko" or "slot" stores. Pathological gambling is a disease that afflicts many people; hence, psychiatric and social welfare professionals should continue to stress the dangers of and offer prevention programs for "pachinko" or

Frequency Reconfigurable Circular Patch Antenna with an Arc-Shaped Slot Ground Controlled by PIN Diodes

Directory of Open Access Journals (Sweden)

Yao Chen

2017-01-01

Full Text Available In this paper, a compact frequency reconfigurable circular patch antenna with an arc-shaped slot loaded in the ground layer is proposed for multiband wireless communication applications. By controlling the ON/OFF states of the five PIN diodes mounted on the arc-shaped slot, the effective length of the arc-shaped slot and the effective length of antennas current are changed, and accordingly six-frequency band reconfiguration can be achieved. The simulated and measured results show that the antenna can operate from 1.82 GHz to 2.46 GHz, which is located in DCS1800 (1.71–1.88 GHz, UMTS (2.11–2.20 GHz, WiBro (2.3–2.4 GHz, and Bluetooth (2.4–2.48 GHz frequency bands and so forth. Compared to the common rectangular slot circular patch antenna, the proposed arc-shaped slot circular patch antenna not only has a better rotational symmetry with the circular patch and substrate but also has more compact size. For the given operating frequency at 1.82 GHz, over 55% area reduction is achieved in this design with respect to the common design with rectangular slot. Since the promising frequency reconfiguration, this antenna may have potential applications in modern multiband and multifunctional mobile communication systems.

Pathological gambling: A comparison of gambling at German-style slot machines and "Classical" gambling.

Science.gov (United States)

Fabian, T

1995-09-01

German-style slot machines and related legal issues are described. On the basis of a survey on 437 members of self-help groups (Gamblers Anonymous) in Germany, slot machine gamblers were compared with casino gamblers on such variables as sociodemographic data, gambling behaviour, financial expenditure, emotional experience while gambling, symptoms of pathological gambling, psychosocial consequences and gambling related delinquency. The casino gamblers' gambling behaviour is financially more extensive. There were similarities regarding the emotional intensity of the gambling experience. However the casino gamblers show more pronounced symptoms of pathological gambling and the psychosocial consequences of their gambling behaviour are more severe. In spite of these differences, the data show that for young people slot machines can be as stimulating and therefore as dangerous as casino gambling. The young slot machine gambler runs a similar risk of acquiring a pathological gambling habit as the casino gambler.

Advanced hybrid query tree algorithm based on slotted backoff mechanism in RFID

Directory of Open Access Journals (Sweden)

XIE Xiaohui

2013-12-01

Full Text Available The merits of performance quality for a RFID system are determined by the effectiveness of tag anti-collision algorithm.Many algorithms for RFID system of tag identification have been proposed,but they all have obvious weaknesses,such as slow speed of identification,unstable and so on.The existing algorithms can be divided into two groups,one is based on ALOHA and another is based on query tree.This article is based on the hybrid query tree algorithm,combined with a slotted backoff mechanism and a specific encoding (Manchester encoding.The number of value“1” in every three consecutive bits of tags is used to determine the tag response time slots,which will greatly reduce the time slot of the collision and improve the recognition efficiency.

Finite element analysis of slot wall deformation in stainless steel and titanium orthodontic brackets during simulated palatal root torque.

Science.gov (United States)

Magesh, Varadaraju; Harikrishnan, Pandurangan; Kingsly Jeba Singh, Devadhas

2018-04-01

Torque applied on anterior teeth is vital for root positioning and stability. The aim of this study was to evaluate the detailed slot wall deformation in stainless steel (SS) and titanium (Ti) edgewise brackets during palatal root torque using finite element analysis. A finite element model was developed from a maxillary central incisor SS bracket (0.022 in). The generated torque values from an SS rectangular archwire (0.019 × 0.025 in) while twisting from 5° to 40° were obtained experimentally by a spine tester, and the calculated torque force was applied in the bracket slot. The deformations of the slot walls in both SS and Ti brackets were measured at various locations. There were gradual increases in the deformations of both bracket slot walls from the bottom to top locations. In the SS bracket slot for the 40° twist, the deformations were 9.28, 36.8, and 44.8 μm in the bottom, middle, and top slot wall locations, respectively. Similarly, in the Ti bracket slot for the 40° twist, the deformations were 39.2, 62.4, and 76.2 μm in the bottom, middle, and top slot wall locations, respectively. The elastic limits were reached at 28° for SS and at 37° for Ti. Both SS and Ti bracket slots underwent deformation during torque application. There are variations in the deformations at different locations in the slot walls and between the materials. Copyright © 2017 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Evaluation of detectable angle of mid-infrared slot antennas

Science.gov (United States)

Obara, R.; Horikawa, J.; Shimakage, H.; Kawakami, A.

2017-07-01

For evaluations of a mid-infrared (MIR) detectors with antenna, we constructed an angular dependence measurement system of the antenna properties. The fabricated MIR detector consisted of twin slot antennas and a bolometer. The area of the slot antennas was designed to be 2.6 × 0.2 μm2 as to resonate at 61 THz, and they were located parallel and separated 1.6 μm each other. The bolometer was fabricated using by a 7.0-nm thick NbN thin film, and located at the center of the twin antennas. We measured polarization angle dependence and directivity, and showed that the MIR antennas have polarization dependence and directivity like radiofrequency antennas.

Clean Air Slots Amid Dense Atmospheric Pollution in Southern Africa

Science.gov (United States)

Hobbs, Peter V.

2003-01-01

During the flights of the University of Washington's Convair-580 in the Southern African Regional Science Initiative (SAFARI 2000) in southern Africa, a phenomenon was observed that has not been reported previously. This was the occurrence of thin layers of remarkably clean air, sandwiched between heavily polluted air, which persisted for many hours during the day. Photographs are shown of these clean air slots (CAS), and particle concentrations and light scattering coefficients in and around such slot are presented. An explanation is proposed for the propensity of CAS to form in southern Africa during the dry season.

Wideband, Low-Profile, Dual-Polarized Slot Antenna with an AMC Surface for Wireless Communications

Directory of Open Access Journals (Sweden)

Wei Hu

2016-01-01

Full Text Available A wideband dual-polarized slot antenna loaded with artificial magnetic conductor (AMC is proposed for WLAN/WIMAX and LTE applications. The slot antenna mainly consists of two pairs of arrow-shaped slots along the diagonals of the square patch. Stepped microstrip feedlines are placed orthogonally to excite the horizontal and vertical polarizations of the antenna. To realize unidirectional radiation and low profile, an AMC surface composed of 7 × 7 unit cells is designed underneath a distance of 0.09λ0 (λ0 being the wavelength in free space at 2.25 GHz from the slot antenna. Both the dual-polarized slot antenna and the AMC surface are fabricated and measured. Experimental results demonstrate that the proposed antenna achieves for both polarizations a wide impedance bandwidth (return loss 10 dB of 36.7%, operating from 1.96 to 2.84 GHz. The isolation between the two input ports keeps higher than 29 dB whereas the cross-polarization levels basically maintain lower than −30 dB across the entire frequency band. High front-to-back ratios better than 22 dB and a stable gain higher than 8 dBi are obtained over the whole band.

Wave Propagation in a coaxial waveguide with a periodic slot array

CERN Document Server

Alesini, D; Garganese, C; Migliorati, M; Palumbo, L

2001-01-01

In this paper we present the numerical and experimental study of the electromagnetic elds that propagate in a coaxial waveguide having periodic slots in the inner conductor. The aim of the work is to estimate the e ects of the holes on the phase velocity of the eld propagating in structures like the LHC liner, and to which extent these elds can be considered synchronous with the generating beam. To this end we have performed a numerical analysis by using the MAFIA simulation code, and have obtained, for a given geometry, the ampli- tude of the slowing down of the phase velocity due to the presence of the slot array. We have then performed a set of measurements of this e ect on a simple coaxial resonator, measuring the shift of the resonance frequencies produced by the slots. This shift, related to the phase velocity, has been compared with the results obtained with the simulations.

Slot-waveguide biochemical sensor.

Science.gov (United States)

Barrios, Carlos A; Gylfason, Kristinn B; Sánchez, Benito; Griol, Amadeu; Sohlström, H; Holgado, M; Casquel, R

2007-11-01

We report an experimental demonstration of an integrated biochemical sensor based on a slot-waveguide microring resonator. The microresonator is fabricated on a Si3N4-SiO2 platform and operates at a wavelength of 1.3 microm. The transmission spectrum of the sensor is measured with different ambient refractive indices ranging from n=1.33 to 1.42. A linear shift of the resonant wavelength with increasing ambient refractive index of 212 nm/refractive index units (RIU) is observed. The sensor detects a minimal refractive index variation of 2x10(-4) RIU.

Effects of Ceramic Density and Sintering Temperature on the Mechanical Properties of a Novel Polymer-Infiltrated Ceramic-Network Zirconia Dental Restorative (Filling) Material.

Science.gov (United States)

Li, Weiyan; Sun, Jian

2018-05-10

BACKGROUND Polymer-infiltrated ceramic-network (PICN) dental material is a new and practical development in orthodontics. Sintering is the process of forming a stable solid mass from a powder by heating without melting. The aim of this study was to evaluate the effects of sintering temperature on the mechanical properties of a PICN zirconia dental material. MATERIAL AND METHODS A dense zirconia ceramic and four PICN zirconia dental materials, with varying porosities, were sintered at three different temperatures; 12 PICN zirconia dental materials based on these porous ceramics were prepared, as well as a pure polymer. After the specimen preparation, flexural strength and elastic modulus values were measured using the three-point bending test, and fracture toughness were determined by the single-edge notched beam (SENB) method. The Vickers hardness test method was used with an indentation strength (IS) test. Scanning electron microscopy (SEM) was used to examine the microstructure of the ceramic surface and the fracture surface. RESULTS Mechanical properties of the PICN dental materials, including flexural strength, elastic modulus, fracture toughness, and hardness, were more similar to the properties of natural teeth when compared with traditional dental ceramic materials, and were affected by the density and sintering temperature. SEM showed that the porous ceramic network became cohesive and that the length of cracks in the PICN dental material was reduced. CONCLUSIONS PICN zirconia dental materials were characterized by similar mechanical properties to natural dental tissues, but further studies are required continue to improve the similarities with natural human enamel and dentin.

Shape-optimization of round-to-slot holes for improving film cooling effectiveness on a flat surface

Science.gov (United States)

Huang, Ying; Zhang, Jing-zhou; Wang, Chun-hua

2018-06-01

Single-objective optimization for improving adiabatic film cooling effectiveness is performed for single row of round-to-slot film cooling holes on a flat surface by using CFD analysis and surrogate approximation methods. Among the main geometric parameters, dimensionless hole-to-hole pitch ( P/ d) and slot length-to-diameter ( l/ d) are fixed as 2.4 and 2 respectively, and the other parameters (hole height-to-diameter ratio, slot width-to-diameter and inclination angle) are chosen as the design variables. Given a wide range of possible geometric variables, the geometric optimization of round-to-slot holes is carried out under two typical blowing ratios of M = 0.5 and M = 1.5 by selecting a spatially-averaged adiabatic film cooling effectiveness between x/ d = 2 and x/ d = 12 as the objective function to be maximized. Radial basis function neural network is applied for constructing the surrogate model and then the optimal design point is searched by a genetic algorithm. It is revealed that the optimal round-to-slot hole is of converging feature under a low blowing ratio but of diffusing feature under a high blowing ratio. Further, the influence principle of optimal round-to-slot geometry on film cooling performance is illustrated according to the detailed flow and thermal behaviors.

Lattice Boltzmann study of slip flow over structured surface with transverse slots

Science.gov (United States)

Chen, Wei; Wang, Kai; Wang, Lei; Hou, Guoxiang; Leng, Wenjun

2018-04-01

Slip flow over structured superhydrophobic surface with transverse slots is investigated by the lattice Boltzmann method. The Shan-Chen multiphase model is employed to simulate the flow over gas bubbles in the slots. The Carnahan-Starling equation of state is applied to obtain large density ratio. The interface thickness of the multiphase model is discussed. We find that the Cahn number Cn should be smaller than 0.02 when the temperature T = 0.5T c to restrict the influence of interface thickness on slip length. Influences of slot fraction on slip length is then studied, and the result is compared with single LB simulation of which the interface is treated as free-slip boundary. The slip length obtained by the multiphase model is a little smaller. After that, the shape of the liquid-gas interface is considered, and simulations with different initial protrusion angles and capillary numbers are performed. Effective slip length as a function of initial protrusion angle is obtained. The result is in qualitative agreement with a previous study and main features are reproduced. Furthermore, the influence of Capillary number Ca is studied. Larger Ca causes larger interface deformation and smaller slip length. But when the interface is concaving into the slot, this influence is less obvious.

Calculation of induced rotor current in induction motors using a slotted semi-analytical harmonic model

NARCIS (Netherlands)

Sprangers, R.L.J.; Gysen, B.L.J.; Paulides, J.J.H.; Waarma, J.; Lomonova, E.A.

2014-01-01

Recently, strong improvements have been made in the applicability of harmonic modeling techniques for electrical machines with slotted structures. Various implementations for permanent magnet motors and actuators have been investigated and applied in design and optimization tools. For the slotted

Theoretical and experimental study of microstrip-to-slot line uniplanar transition

Science.gov (United States)

Yook, Jong-Gwan; Dib, Nihad I.; Katehi, Linda P. B.; Simons, Rainee N.; Taub, Susan R.

1994-05-01

Recent advances in MMCI technology make it possible to construct transitions from CPW-to-microstrip with via hole, microstrip-to-slot line and microshield line-to-CPW all of which have potential applications in the feed network of antennas. In this study we investigate the characteristics of the microstrip-to-slot line uniplanar transition using the finite element methods (FEM) and finite difference time domain (FDTD) techniques, and compared the theoretical results with the measurements. In both cases, the results agree with the measurements within a few percent.

Nonlinear theory of a cyclotron autoresonance maser (CARM) amplifier with outer-slotted-coaxial waveguide

International Nuclear Information System (INIS)

Qiu Chunrong; Ouyang Zhengbiao; Zhang Shichang; Zhang Huibo; Jin Jianbo; Lai Yingxin

2005-01-01

A self-consistent nonlinear theory for the outer-slotted-coaxial-waveguide cyclotron autoresonance maser (CARM) amplifier is presented, which includes the characteristic equation of the wave, coupling equation of the wave with the relativistic electron beam and the simulation model. The influences of the magnetic field, the slot depth and width are investigated. The interesting characteristic of the device is that the mode competition can be efficiently suppressed by slotting the outer wall of the coaxial waveguide. A typical example is given by the theoretical design of a 137 GHz outer-slotted-coaxial-waveguide CARM amplifier by utilizing an electron beam with a voltage of 90 kV, current of 50 A, velocity pitch angle of 0.85 and a magnetic field of 43.0 kG. The nonlinear simulation predicts a power of 467.9 kW, an electronic efficiency of 10.4% and a saturated gain of 46.7 dB, if the electron beam has no velocity spread. However, the axial velocity spread deteriorates the device; for example, if the axial velocity spread is 2%, the peak power decreases to 332.4 kW with an efficiency of 7.4% and a saturated gain of 45.22 dB. Simulation shows that the efficiency of the outer-slotted-coaxial-waveguide CARM amplifier may be increased from 10.4% to 29.6% by tapering the magnetic field

Airport slots and slot allocation: driver for mismatch between airline network and city needs? : the case of Rotterdam The Hague Airport

NARCIS (Netherlands)

van den Brandt, Marc; Mujica Mota, Miguel; Boosten, Geert; Hromádka, Martin

2014-01-01

Aviation increasingly faces capacity challenges exposing inefficiencies and shortcomings of aviation related processes and systems. The European slot allocation system was designed in an era with little to no capacity constraints, now resulting in regulations not fitting in today’s developments.

Numerical investigation of the LM MHD flows in a curved duct with an FCI with varying slot locations

International Nuclear Information System (INIS)

Yang, Jong Hoon; Yan, Yue; Kim, Chang Nyung

2016-01-01

Highlights: • This study numerically investigates the liquid-metal magnetohydrodynamic flows in a curved duct with an FCI. • The effects of the location of FCI slot and of the curvature radius on the flow behavior are reviewed. • The influence of the FCI slot position on the equalization of the pressure in the inner fluid region (inside the FCI) and the gap fluid region (outer the FCI) is examined. - Abstract: This study numerically investigates the liquid-metal (LM) magnetohydrodynamic (MHD) flows in a curved duct with an FCI having three different slot locations and having no slot under a uniform magnetic field perpendicular to the duct. The flow velocity, current density, electric potential, Lorentz force, and pressure in different flow situations are presented in detail. The effects of the location of FCI slot and of the curvature radius on the flow behavior are reviewed. The flow field is examined with an introduction of the electric-field component and electro-motive component of the current, allowing us to analyze the interdependency of the flow variables. The effect of the FCI slot position on the equalization of the pressure in the inner fluid region (inside the FCI) and the gap fluid region (outer the FCI) is examined. The result shows that and the case with an FCI slot located in the neutral position yields the smallest pressure gradient in the main flow direction among the cases with an FCI slot, resulting in the smallest pressure drop. Also, in a flow situation with smaller radius of curvature with the FCI slot in the neutral position, the axial velocity near the inner (in terms of the curvature) part of a cross-section is higher than that near the outer part.

Of Slot Machines and Broken Test Tubes

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 19; Issue 5. Of Slot Machines and Broken Test Tubes. S Mahadevan. General Article Volume 19 Issue 5 May 2014 pp 395-405. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/019/05/0395-0405. Keywords.

A new method for the design of slot antenna arrays: Theory and experiment

KAUST Repository

Clauzier, Sebastien

2016-04-10

The present paper proposes and validates a new general design methodology that can be used to automatically find proper positions and orientations of waveguide-based radiating slots capable of realizing any given radiation beam profile. The new technique combines basic radiation theory and waveguide propagation theory in a novel analytical model that allows the prediction of the radiation characteristics of generic slots without the need to perform full-wave numerical solution. The analytical model is then used to implement a low-cost objective function within a global optimization scheme (here genetic algorithm.) The algorithm is then deployed to find optimum positions and orientations of clusters of radiating slots cut into the waveguide surface such that any desired beam pattern can be obtained. The method is verified using both full-wave numerical solution and experiment.

Numerical exploration of non-axisymmetric divertor closure in the small angle slot (SAS) divertor at DIII-D

Science.gov (United States)

Frerichs, H.; Schmitz, O.; Covele, B.; Feng, Y.; Guo, H. Y.; Hill, D.

2018-05-01

Numerical simulations of toroidal asymmetries in a tightly baffled small angle slot (SAS) divertor on the DIII-D tokamak show that toroidal asymmetries in divertor closure result in (non-axisymmetric) local onset of detachment within a density window of 10-15% on top of the nominal threshold separatrix density. The SAS divertor is explored at DIII-D for improving access to cold, dissipative/detached divertor conditions. The narrow width of the slot divertor coupled with a small magnetic field line-to-target angle facilitates the buildup of neutral density, thereby increasing radiative and neutrals-related (atoms and molecules) losses in the divertor. Small changes in the strike point location can be expected to have a large impact on divertor conditions. The combination of misaligned slot structure and non-axisymmetric perturbations to the magnetic field configuration causes the strike point to move along the divertor target plate, possibly leaving the divertor slot at some locations. The latter extreme case essentially introduces an opening in the divertor slot from where recycling neutrals can easily escape, and thereby degrade the performance of the slot divertor. Such a strike point dislocation is approximated by a finite gap in the divertor baffle for which 3D edge plasma and neutral gas simulations are performed with the EMC3-EIRENE code.

Tuning ZOR in ENZ waveguide using a single longitudinal slot and equivalent circuit parameter extraction

DEFF Research Database (Denmark)

Vojnovic, Nebojsa; Jokanovic, Branka; Mitrovic, Miranda

2014-01-01

In this paper, the effects of placing a longitudinal slot in the channel region of a rectangular waveguide ENZ structure, are analyzed. A following investigation showed that changing the length of this slot can be employed to achieve tuning of only the tunneling frequency. Maximum resonant freque...

Dynamic Allocation of SPM Based on Time-Slotted Cache Conflict Graph for System Optimization

Science.gov (United States)

Wu, Jianping; Ling, Ming; Zhang, Yang; Mei, Chen; Wang, Huan

This paper proposes a novel dynamic Scratch-pad Memory allocation strategy to optimize the energy consumption of the memory sub-system. Firstly, the whole program execution process is sliced into several time slots according to the temporal dimension; thereafter, a Time-Slotted Cache Conflict Graph (TSCCG) is introduced to model the behavior of Data Cache (D-Cache) conflicts within each time slot. Then, Integer Nonlinear Programming (INP) is implemented, which can avoid time-consuming linearization process, to select the most profitable data pages. Virtual Memory System (VMS) is adopted to remap those data pages, which will cause severe Cache conflicts within a time slot, to SPM. In order to minimize the swapping overhead of dynamic SPM allocation, a novel SPM controller with a tightly coupled DMA is introduced to issue the swapping operations without CPU's intervention. Last but not the least, this paper discusses the fluctuation of system energy profit based on different MMU page size as well as the Time Slot duration quantitatively. According to our design space exploration, the proposed method can optimize all of the data segments, including global data, heap and stack data in general, and reduce the total energy consumption by 27.28% on average, up to 55.22% with a marginal performance promotion. And comparing to the conventional static CCG (Cache Conflicts Graph), our approach can obtain 24.7% energy profit on average, up to 30.5% with a sight boost in performance.

Compact broadband circularly polarised slot antenna for universal UHF RFID readers

DEFF Research Database (Denmark)

Xu, Bo; Zhang, Shuai; Liu, Yusha

2015-01-01

A compact broadband circularly polarised (CP) slot antenna is designed for universal ultra-high-frequency (UHF) radio frequency identification (RFID) readers. The antenna consists of an L-shaped metal strip and a square-slot-loaded ground plane with four tuning stubs. The total size is 100 mm×100mm......×1.6 mm. The measured –10 dB impedance bandwidth is 40.7% (772–1166 MHz) and the measured 3 dB axial ratio (AR) bandwidth is 13.9% (840–965 MHz). Both the impedance and AR bandwidth cover the worldwide UHF RFID band....

Electromagnetically induced transparency and ultraslow optical solitons in a coherent atomic gas filled in a slot waveguide.

Science.gov (United States)

Xu, Jin; Huang, Guoxiang

2013-02-25

We investigate the electromagnetically induced transparency (EIT) and nonlinear pulse propagation in a Λ-type three-level atomic gas filled in a slot waveguide, in which electric field is strongly confined inside the slot of the waveguide due to the discontinuity of dielectric constant. We find that EIT effect can be greatly enhanced due to the reduction of optical-field mode volume contributed by waveguide geometry. Comparing with the atomic gases in free space, the EIT transparency window in the slot waveguide system can be much wider and deeper, and the Kerr nonlinearity of probe laser field can be much stronger. We also prove that using slot waveguide ultraslow optical solitons can be produced efficiently with extremely low generation power.

Multiphysics modelling and simulation of dry laser cleaning of micro-slots with particle contaminants

International Nuclear Information System (INIS)

Yue Liyang; Wang Zengbo; Li Lin

2012-01-01

Light could interact differently with thin-film contaminants and particle contaminates because of their different surface morphologies. In the case of dry laser cleaning of small transparent particles, it is well known that particles could function like mini-lenses, causing a localized near-field hot spot effect on the cleaning process. This paper looks into a special, yet important, phenomenon of dry laser cleaning of particles trapped in micro-sized slots. The effects of slot size, particle size and particle aggregate states in the cleaning process have been theoretically investigated, based on a coupled electromagnetic-thermal-mechanical multiphysics modelling and simulation approach. The study is important for the development and optimization of laser cleaning processes for contamination removal from cracks and slots. (paper)

Slot Machine Response Frequency Predicts Pathological Gambling

DEFF Research Database (Denmark)

Linnet, Jakob; Rømer Thomsen, Kristine; Møller, Arne

2013-01-01

. This study tested the hypothesis that response frequency is associated with symptom severity in pathological gambling. We tested response frequency among twenty-two pathological gambling sufferers and twenty-one non-problem gamblers on a commercially available slot machine, and screened for pathological...... in individuals with exacerbated pathological gambling symptoms. These findings may have important implications for detecting behaviors underlying pathological gambling....

Modeling arbitrarily directed slots that are narrow both in width and depth with regard to the FDTD spatial cell. [Finite Difference-Time Domain (TDTD)

Energy Technology Data Exchange (ETDEWEB)

Riley, D.J.; Turner, C.D.

1991-01-01

The Hybrid Thin-Slot Algorithm (HTSA) integrates a transient integral-equation solution for an aperture in an infinite plane into a finite-difference time-domain (FDTD) code. The technique was introduced for linear apertures and was extended to include wall loss and lossy internal gaskets. A general implementation for arbitrary thin slots is briefly described here. The 3-D FDTD-code TSAR was selected for the implementation. The HTSA does not provide universal solutions to the narrow slot problem, but has merits appropriate for particular applications. The HTSA is restricted to planar slots, but can solve the important case that both the width and depth of the slot are narrow compared to the FDTD spatial cell. IN addition, the HTSA is not bound to the FDTD discrete spatial and time increments, and therefore, high-resolution solutions for the slot physics are possible. The implementation of the HTSA into TSAR is based upon a slot data file'' that includes the cell indices where the desired slots are exist within the FDTD mesh. For an HTSA-defined slot, the wall region local to the slot is shorted, and therefore, to change the slot's topology simply requires altering the file to include the desired cells. 7 refs.

Three-dimensional hard and soft tissue imaging of the human cochlea by scanning laser optical tomography (SLOT.

Directory of Open Access Journals (Sweden)

Nadine Tinne

Full Text Available The present study focuses on the application of scanning laser optical tomography (SLOT for visualization of anatomical structures inside the human cochlea ex vivo. SLOT is a laser-based highly efficient microscopy technique which allows for tomographic imaging of the internal structure of transparent specimens. Thus, in the field of otology this technique is best convenient for an ex vivo study of the inner ear anatomy. For this purpose, the preparation before imaging comprises decalcification, dehydration as well as optical clearing of the cochlea samples in toto. Here, we demonstrate results of SLOT imaging visualizing hard and soft tissue structures with an optical resolution of down to 15 μm using extinction and autofluorescence as contrast mechanisms. Furthermore, the internal structure can be analyzed nondestructively and quantitatively in detail by sectioning of the three-dimensional datasets. The method of X-ray Micro Computed Tomography (μCT has been previously applied to explanted cochlea and is solely based on absorption contrast. An advantage of SLOT is that it uses visible light for image formation and thus provides a variety of contrast mechanisms known from other light microscopy techniques, such as fluorescence or scattering. We show that SLOT data is consistent with μCT anatomical data and provides additional information by using fluorescence. We demonstrate that SLOT is applicable for cochlea with metallic cochlear implants (CI that would lead to significant artifacts in μCT imaging. In conclusion, the present study demonstrates the capability of SLOT for resolution visualization of cleared human cochleae ex vivo using multiple contrast mechanisms and lays the foundation for a broad variety of additional studies.

Research on TIG weld machine of the upper side ring slot of Gd-rod technology reconstruct

International Nuclear Information System (INIS)

Fang Shixiang; Lan Zhibing; Cui Quhu

2010-01-01

The research on TIG weld machine of the upper side ring slot of Gd-rod existent matter: seal electrical source got up difficulty; control system had graveness aging; space between was adjusted precision lowness; welding torch lay mode and structure were not in reason. carried through all around technology reconstruct: had chosen the best of TIG weld machine; designed ignite arc device, designed optics imaging device, designed tungsten mighty axis direction auto conditioning, was provided with arc slot, adopted PLC to control the whole system and realization auto control. After TIG weld machine of the upper side ring slot of Gd-rod technology reconstruct research , provided with arc slot the first time in the Gd-rod of nuclear fuel, optimized the weld technics, improved welding line melt width and deep equality, stability, and great breadth advanced nuclear fuel product line technology and throughput. (authors)

Study of Allocation Guaranteed Time Slot Wireless Body Area Networks Based on IEEE 802.15.4

Science.gov (United States)

Yundra, E.; Harsono, G. D.

2018-04-01

This paper aims to determine the size of the Guaranteed Time Slot (GTS) on the super frame structure required for each sensor as well as to know the performance of the GTS resized system compared to the GTS standard on IEEE 802.15.4. This article proposes a scheme to improve IEEE 802.15.4 medium access control, called allocation Guaranteed Time Slot (ALGATIS). ALGATIS is expected to effectively allocate guaranteed time slot to the requested sensors, it adjusts the length of the slot in super frame duration based on the length of the packet data. This article presents a simulation experiment of IEEE 802.15.4, especially for star network, to predict the throughput of networks and average energy consumption. The simulation experiments show that the performance of ALGATIS is better than that of IEEE 802.15.4 standard in term of the throughput of networks and average energy consumption

Design of dual band FSS by using quadruple L-slot technique

Science.gov (United States)

Fauzi, Noor Azamiah Md; Aziz, Mohamad Zoinol Abidin Abd.; Said, Maizatul Alice Meor; Othman, Mohd Azlishah; Ahmad, Badrul Hisham; Malek, Mohd Fareq Abd

2015-05-01

This paper presents a new design of dual band frequency selective surface (FSS) for band pass microwave transmission application. FSS can be used on energy saving glass to improve the transmission of wireless communication signals through the glass. The microwave signal will be attenuate when propagate throughout the different structure such as building. Therefore, some of the wireless communication system cannot be used in the optimum performance. The aim of this paper is designed, simulated and analyzed the new dual band FSS structure for microwave transmission. This design is based on a quadruple L slot combined with cross slot to produce pass band at 900 MHz and 2.4 GHz. The vertical of pair inverse L slot is used as the band pass for the frequency of 2.4GHz. While, the horizontal of pair inverse L slot is used as the band pass at frequency 900MHz. This design is simulated and analyzed by using Computer Simulation Technology (CST) Microwave Studio (MWS) software. The characteristics of the transmission (S21) and reflection (S11) of the dual band FSS were simulater and analyzed. The bandwidth of the first band is 118.91MHz which covered the frequency range from 833.4MHz until 952.31MHz. Meanwhile, the bandwidth for the second band is 358.84MHz which covered the frequency range from 2.1475GHz until 2.5063GHz. The resonance/center frequency of this design is obtained at 900MHz with a 26.902dB return loss and 2.37GHz with 28.506dB a return loss. This FSS is suitable as microwave filter for GSM900 and WLAN 2.4GHz application.

Evaluation of surface roughness of the bracket slot floor—a 3D perspective study

Directory of Open Access Journals (Sweden)

Chetankumar O. Agarwal

2016-01-01

Full Text Available Abstract Background An important constituent of an orthodontic appliance is orthodontic brackets. It is either the bracket or the archwire that slides through the bracket slot, during sliding mechanics. Overcoming the friction between the two surfaces demands an important consideration in an appliance design. The present study investigated the surface roughness of four different commercially available stainless steel brackets. Methods All tests were carried out to analyse quantitatively the morphological surface of the bracket slot floor with the help of scanning electron microscope (SEM machine and to qualitatively analyse the average surface roughness (Sa of the bracket slot floor with the help of a three-dimensional (3D non-contact optical surface profilometer machine. Results The SEM microphotographs were evaluated with the help of visual analogue scale, the surface roughness for group A = 0—very rough surface, group C = 1—rough surface, group B = 2—smooth surface, and group D = 3—very smooth surface. Surface roughness evaluation with the 3D non-contact optical surface profilometer machine was highest for group A, followed by group C, group B and group D. Groups B and D provided smooth surface roughness; however, group D had the very smooth surface with values 0.74 and 0.75 for mesial and distal slots, respectively. Conclusions Evaluation of surface roughness of the bracket slot floor with both SEM and profilometer machine led to the conclusion that the average surface roughness was highest for group A, followed by group C, group B and group D.

Multiband Slot-Based Dual Composite Right/Left-Handed Transmission Line

Directory of Open Access Journals (Sweden)

E. Abdo-Sanchez

2012-10-01

Full Text Available A dual Composite Right-/Left-Handed Transmission Line (CRLH TL implementation that presents multiband behaviour is proposed in this contribution. The artificial TL is realized by loading a host microstrip line with alternate rectangular stubs and slots. The required series and shunt immittances are respectively provided by the slot and the stub. Due to the distributed nature of these immittances, the resultant phase response presents theoretically infinite RH and LH alternate bands, thus being appropriate for multiband applications. The design methodology is described with the help of a proposed TLs-based equivalent circuit and highlights the simplicity for balance condition. Full wave simulated results of the dispersion characteristics and frequency response of a unit-cell and a three-cells structure are presented.

Studies on diversion cross-flow between two parallel channels communicating by a lateral slot. II

International Nuclear Information System (INIS)

Tapucu, A.; Merilo, M.

1977-01-01

The axial pressure variations of two parallel channels with single phase flows communicating by a long lateral slot have been studied experimentally. Using mass and momentum conservation principles, the axial pressure variations have been derived in terms of two parameters ksub(d) and ksub(r), for donor and recipient channels, respectively. These parameters include the combined effect of fluid transferred from donor to recipient channel, and drag force brought on by the connection gap, and are functions of the velocities and slot geometry parameters. A pressure difference oscillation between channels along the slot has been detected which is sinusoidal with wave lengths which seem to be a function of the gap clearance. (Auth.)

Band structures in two-dimensional phononic crystals with periodic Jerusalem cross slot

Science.gov (United States)

Li, Yinggang; Chen, Tianning; Wang, Xiaopeng; Yu, Kunpeng; Song, Ruifang

2015-01-01

In this paper, a novel two-dimensional phononic crystal composed of periodic Jerusalem cross slot in air matrix with a square lattice is presented. The dispersion relations and the transmission coefficient spectra are calculated by using the finite element method based on the Bloch theorem. The formation mechanisms of the band gaps are analyzed based on the acoustic mode analysis. Numerical results show that the proposed phononic crystal structure can yield large band gaps in the low-frequency range. The formation mechanism of opening the acoustic band gaps is mainly attributed to the resonance modes of the cavities inside the Jerusalem cross slot structure. Furthermore, the effects of the geometrical parameters on the band gaps are further explored numerically. Results show that the band gaps can be modulated in an extremely large frequency range by the geometry parameters such as the slot length and width. These properties of acoustic waves in the proposed phononic crystals can potentially be applied to optimize band gaps and generate low-frequency filters and waveguides.

Numerical exploration of non-axisymmetric divertor closure in the small angle slot (SAS) divertor at DIII-D

Science.gov (United States)

Frerichs, Heinke; Schmitz, Oliver; Covele, Brent; Guo, Houyang; Hill, David; Feng, Yuhe

2017-10-01

In the Small Angle Slot (SAS) divertor in DIII-D, the combination of misaligned slot structure and non-axisymmetric perturbations to the magnetic field causes the strike point to vary radially along the divertor slot and even leave it at some toroidal locations. This effect essentially introduces an opening in the divertor slot from where recycling neutrals can easily escape, and thereby degrade performance of the slot divertor. This effect has been approximated by a finite gap in the divertor baffle. Simulations with EMC3-EIRENE show that a toroidally localized loss of divertor closure can result in non-axisymmetric divertor densities and temperatures. This introduces a density window of 10-15% on top of the nominal threshold separatrix density during which a non-axisymmetric onset of local detachment occurs, initially leaving the gap and up to 60 deg beyond that still attached. Conversely, the impact of such toroidally localized divertor perturbations on the toroidal symmetry of midplane separatrix conditions is small. This work has been funded by the U.S. Department of Energy under Early Career Award Grant DE-SC0013911, and Grant DE-FC02-04ER54698.

Burnout and distribution of liquid between the flow core and wall films in narrow slot channels

Science.gov (United States)

Boltenko, E. A.; Shpakovskii, A. A.

2010-03-01

Previous works on studying distribution of liquid between the flow core and wall films in narrow slot channels are briefly reviewed. Interrelation between mass transfer processes and burnout is shown. A procedure for calculating burnout on convex and concave heat-transfer surfaces in narrow slot channels is presented.

Dark Flow, Depression and Multiline Slot Machine Play.

Science.gov (United States)

Dixon, Mike J; Stange, Madison; Larche, Chanel J; Graydon, Candice; Fugelsang, Jonathan A; Harrigan, Kevin A

2018-03-01

Multiline slot machines allow for a unique outcome type referred to as a loss disguised as a win (LDW). An LDW occurs when a player gains credits on a spin, but fewer credits than their original wager (e.g. 15-cent gain on a 20-cent wager). These outcomes alter the gambler's play experience by providing frequent, albeit smaller, credit gains throughout a playing session that are in fact net losses. Despite this negative overall value, research has shown that players physiologically respond to LDWs as if they are wins, not losses. These outcomes also create a "smoother" experience for the player that seems to promote a highly absorbing, flow-like state that we have called "dark flow". Past research has indicated that there may be a relationship between problem gambling status and dark flow, as well as between dark flow, depression, and gambling expectancies. In this study, we sought to further understand these relationships, while examining the influence of LDWs on game preference in the context of single versus multiline slots play. We used a realistic slot machine simulator equipped with a force transducer to measure how hard players pressed the spin button following different outcomes. This measure of arousal showed that LDWs were treated similarly to small wins. Participants overwhelmingly preferred the multiline game and experienced more positive affect while playing it, compared to the single-line game. Problem gambling severity index scores were related to dark flow in both games, but this relationship was stronger for the multiline game. Additionally, depression symptomatology and dark flow were strongly correlated in the multiline game, with significant relationships between depression and gambling expectancy, and gambling expectancy and dark flow ratings also emerging.

Ultra-Broad Band Radar Cross Section Reduction of Waveguide Slot Antenna with Metamaterials

Directory of Open Access Journals (Sweden)

Qiang Fu

2016-06-01

Full Text Available To reduce the radar cross section of a waveguide slot antenna, a three-layer metamaterial is presented based on orthogonal double split-ring resonators. The absorption characteristics of three-layer metamaterial are demonstrated by simulation. Moreover, the metamaterials have been loaded on common waveguide slot antenna according to the surface current distribution. The ultra-broad band radar cross section reduction of the antenna with metamaterials had been theoretically and experimentally investigated by radiating and scattering performances. Experimental and simulated results showed that the proposed antenna with metamaterials performed broadband radar cross section reduction from 3.9 GHz to 18 GHz and the gain had been improved due to the coupling effect between slot and the period structure. The maximal radar cross section reduction achieved 17.81 dB at 8.68 GHz for x-polarized incidence and 21.79 dB at 6.25 GHz for y-polarized waves.

Wave Pressures on Seawave Slot-Cone Generator

DEFF Research Database (Denmark)

Vicinanza, Diego; Kofoed, Jens Peter; Frigaard, Peter

2006-01-01

This paper presents results on loading action on an innovative caisson breakwater for electricity production. The work reported here contributes to the European Union Sixth Framework programme priority 6.1 (Sustainable Energy System), contract 019831, titled "Full- scale demonstration of robust...... and high efficiency energy converter" (WAVESSG). Information on wave loading acting on Wave Energy Convert (WEC) Seawave Slot-Cone GEnerator (SSG) exposed to extreme wave conditions are reported....

Optimization of silicon waveguides for gas detection application at mid-IR wavelengths

Science.gov (United States)

Butt, M. A.; Kozlova, E. S.

2018-04-01

There are several trace gases such as N2O, CO, CO2, NO, H2O, NO2, NH3, CH4 etc. which have their absorption peaks in Mid-IR spectrum These gases strongly absorb in the mid-IR > 2.5 μm spectral region due to their fundamental rotational and vibrational transitions. In this work, we modelled and optimized three different kinds of waveguides such as rib, strip and slot based on silicon platform to obtain maximum evanescent field ratio. These waveguides are designed at 3.39 μm and 4.67 μm which correspond to the absorption line of methane (CH4) and carbon monoxide (CO) respectively.

Probabilistic Dynamic Framed Slotted ALOHA for RFID Tag Identification

DEFF Research Database (Denmark)

Nguyen, Chuyen T.; Hayashi, Kazunori; Kaneko, Megumi

2013-01-01

In this paper, we study radio frequency identification tag identification problems using framed slotted ALOHA protocol. Each tag will be assumed to participate in the contention with a certain probability. Then, the frame size and the probability will be dynamically controlled by the reader in ev...

Revisiting Street Intersections Using Slot-Based Systems.

Directory of Open Access Journals (Sweden)

Remi Tachet

Full Text Available Since their appearance at the end of the 19th century, traffic lights have been the primary mode of granting access to road intersections. Today, this centuries-old technology is challenged by advances in intelligent transportation, which are opening the way to new solutions built upon slot-based systems similar to those commonly used in aerial traffic: what we call Slot-based Intersections (SIs. Despite simulation-based evidence of the potential benefits of SIs, a comprehensive, analytical framework to compare their relative performance with traffic lights is still lacking. Here, we develop such a framework. We approach the problem in a novel way, by generalizing classical queuing theory. Having defined safety conditions, we characterize capacity and delay of SIs. In the 2-road crossing configuration, we provide a capacity-optimal SI management system. For arbitrary intersection configurations, near-optimal solutions are developed. Results theoretically show that transitioning from a traffic light system to SI has the potential of doubling capacity and significantly reducing delays. This suggests a reduction of non-linear dynamics induced by intersection bottlenecks, with positive impact on the road network. Such findings can provide transportation engineers and planners with crucial insights as they prepare to manage the transition towards a more intelligent transportation infrastructure in cities.

Single-nanoparticle detection with slot-mode photonic crystal cavities

Energy Technology Data Exchange (ETDEWEB)

Wang, Cheng; Kita, Shota; Lončar, Marko, E-mail: loncar@seas.harvard.edu [School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States); Quan, Qimin [Rowland Institute at Harvard University, Cambridge, Massachusetts 02142 (United States); Li, Yihang [School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States); Department of Electronic Engineering, Tsinghua University, Beijing 100084 (China)

2015-06-29

Optical cavities that are capable for detecting single nanoparticles could lead to great progress in early stage disease diagnostics and the study of biological interactions on the single-molecule level. In particular, photonic crystal (PhC) cavities are excellent platforms for label-free single-nanoparticle detection, owing to their high quality (Q) factors and wavelength-scale modal volumes. Here, we demonstrate the design and fabrication of a high-Q (>10{sup 4}) slot-mode PhC nanobeam cavity, which is able to strongly confine light in the slotted regions. The enhanced light-matter interaction results in an order of magnitude improvement in both refractive index sensitivity (439 nm/RIU) and single-nanoparticle sensitivity compared with conventional dielectric-mode PhC cavities. Detection of single polystyrene nanoparticles with radii of 20 nm and 30 nm is demonstrated in aqueous environments (D{sub 2}O), without additional laser and temperature stabilization techniques.

Tunable inkjet-printed slotted waveguide antenna on a ferrite substrate

KAUST Repository

Nafe, Ahmed; Farooqui, Muhammad; Shamim, Atif

2015-01-01

In this work an inkjet-printed frequency-tunable slotted waveguide antenna on a ferrite substrate is reported. Unlike the typical substrate integrated waveguide approach with via holes, a true 3D rectangular waveguide is realized by inkjet-printing

Broadband, Low Sidelobe, Zero Height, Slotted Circular Disk Antenna

African Journals Online (AJOL)

A rigorous mathematical theory for a rotationally symmetrical slotted circular disk antenna was developed. The theory applies the principle of "Gradient Invariance" of electromagnetic fields to determine the field components that are unique and single valued at any point in space. To detemine the radiation characteristics of ...

Two-Slotted Surface Coil Array for Magnetic Resonance Imaging at 4 Tesla

International Nuclear Information System (INIS)

Solis, S. E.; Hernandez, J. A.; Rodriguez, A. O.; Tomasi, D.

2008-01-01

Arrays of antennas have been widely accepted for magnetic resonance imaging applications due to their high signal-to-noise ratio (SNR) over large volumes of interest. A new surface coil based on the magnetron tube and called slotted surface coil, has been recently introduced by our group. This coil design experimentally demonstrated a significant improvement over the circular-shaped coil when used in the receive-only mode. The slotted coils formed a two-sheet structure with a 90 deg. separation and each coil had 6 circular slots. Numerical simulations were performed using the finite element method for this coil design to study the behaviour of the array magnetic field. Then, we developed a two-coil array for brain magnetic resonance imaging to be operated at the resonant frequency of 170 MHz in the transceiver mode. Phantom images were acquired with our coil array and standard pulse sequences on a research-dedicated 4 Tesla scanner. Numerical simulations demonstrated that electromagnetic interaction between the coil elements is negligible, and that the magnetic field showed a good uniformity. In vitro images showed the feasibility of this coil array for standard pulses for high field magnetic resonance imaging

Slot deformation of various stainless steel bracket due to the torque force of the beta-titanium wire

Science.gov (United States)

Huda, M. M.; Siregar, E.; Ismah, N.

2017-08-01

Stainless steel bracket slot deformation ffects the force applied to teeth and it can impede tooth movement and prolong orthodontic treatment time. The aim of this study is to determine the slot deformation due to torque of a 0.021 × 0.025 inch Beta Titanium wire with a torsional angle of 30° and 45° for five different bracket brands: y, 3M, Biom, Versadent, Ormco, and Shinye. The research also aims to compare the deformation and amount of torque among all five bracket brands at torsional angles of 30° and 45°. Fifty stainless steel edgewise brackets from the five bracket group brands (n=10) were attached to acrylic plates. The bracket slot measurements were carried out in two stages. In the first stage, the, deformation was measured by calculating the average bracket slot height using a stereoscopy microscope before and after application of torque. In the second stage, the torque was measured using a torque measurement apparatus. The statistical analysis shows that slot deformations were found on all five bracket brands with a clinical permanent deformation on the Biom (2.79 μm) and Shinye (2.29 μm) brackets. The most torque was observed on the 3M bracket, followed by the Ormco, Versadent, Shinye, and Biom brackets. When the brands were compared, a correlation between bracket slot deformation and the amount of torque was found, but the correlation was not statistically significant for the 3M and Ormco brackets and the Biom and Shinye brackets. There is a difference in the amount of torque between the five brands with a torsional angle of 30° (except the 3M and Ormco brackets) and those with a torsional angle of 45°. The composition of the metal and the manufacturing process are the factors that influence the occurrence of bracket slot deformation and the amount of torque. A manufacturing process using metal injection molding (MIM) and metal compositions of AISI 303 and 17-4 PH stainless steel reduce the risk of deformation.

Slot-type pickup/kicker for AA stochastic cooling

CERN Multimedia

CERN PhotoLab

1979-01-01

A "slotted transmission line" was used for both pickups and kickers of the stochastic cooling systems of the AA. They served for the cooling of the high-density antiproton stack, in momentum and both transverse planes. In the beginning in a single band, 1-2 GHz, later in 2 bands, 2-4 and 4-8 GHz. See also 7906190, 7906193.

Enhanced and selective optical trapping in a slot-graphite photonic crystal.

Science.gov (United States)

Krishnan, Aravind; Huang, Ningfeng; Wu, Shao-Hua; Martínez, Luis Javier; Povinelli, Michelle L

2016-10-03

Applicability of optical trapping tools for nanomanipulation is limited by the available laser power and trap efficiency. We utilized the strong confinement of light in a slot-graphite photonic crystal to develop high-efficiency parallel trapping over a large area. The stiffness is 35 times higher than our previously demonstrated on-chip, near field traps. We demonstrate the ability to trap both dielectric and metallic particles of sub-micron size. We find that the growth kinetics of nanoparticle arrays on the slot-graphite template depends on particle size. This difference is exploited to selectively trap one type of particle out of a binary colloidal mixture, creating an efficient optical sieve. This technique has rich potential for analysis, diagnostics, and enrichment and sorting of microscopic entities.

Design of photonic phased array switches using nano electromechanical systems on silicon-on-insulator integration platform

Science.gov (United States)

Hussein, Ali Abdulsattar

This thesis presents an introduction to the design and simulation of a novel class of integrated photonic phased array switch elements. The main objective is to use nano-electromechanical (NEMS) based phase shifters of cascaded under-etched slot nanowires that are compact in size and require a small amount of power to operate them. The structure of the switch elements is organized such that it brings the phase shifting elements to the exterior sides of the photonic circuits. The transition slot couplers, used to interconnect the phase shifters, are designed to enable biasing one of the silicon beams of each phase shifter from an electrode located at the side of the phase shifter. The other silicon beam of each phase shifter is biased through the rest of the silicon structure of the switch element, which is taken as a ground. Phased array switch elements ranging from 2x2 up to 8x8 multiple-inputs/multiple-outputs (MIMO) are conveniently designed within reasonable footprints native to the current fabrication technologies. Chapter one presents the general layout of the various designs of the switch elements and demonstrates their novel features. This demonstration will show how waveguide disturbances in the interconnecting network from conventional switch elements can be avoided by adopting an innovative design. Some possible applications for the designed switch elements of different sizes and topologies are indicated throughout the chapter. Chapter two presents the design of the multimode interference (MMI) couplers used in the switch elements as splitters, combiners and waveguide crossovers. Simulation data and design methodologies for the multimode couplers of interest are detailed in this chapter. Chapter three presents the design and analysis of the NEMS-operated phase shifters. Both simulations and numerical analysis are utilized in the design of a 0°-180° capable NEMS-operated phase shifter. Additionally, the response of some of the designed photonic phased

Constraint-based local search for container stowage slot planning

DEFF Research Database (Denmark)

Pacino, Dario; Jensen, Rune Møller; Bebbington, Tom

2012-01-01

-sea vessels. This paper describes the constrained-based local search algorithm used in the second phase of this approach where individual containers are assigned to slots in each bay section. The algorithm can solve this problem in an average of 0.18 seconds per bay, corresponding to a 20 seconds runtime...

Design of Ultra-Wideband Tapered Slot Antenna by Using Binomial Transformer with Corrugation

Science.gov (United States)

Chareonsiri, Yosita; Thaiwirot, Wanwisa; Akkaraekthalin, Prayoot

2017-05-01

In this paper, the tapered slot antenna (TSA) with corrugation is proposed for UWB applications. The multi-section binomial transformer is used to design taper profile of the proposed TSA that does not involve using time consuming optimization. A step-by-step procedure for synthesis of the step impedance values related with step slot widths of taper profile is presented. The smooth taper can be achieved by fitting the smoothing curve to the entire step slot. The design of TSA based on this method yields results with a quite flat gain and wide impedance bandwidth covering UWB spectrum from 3.1 GHz to 10.6 GHz. To further improve the radiation characteristics, the corrugation is added on the both edges of the proposed TSA. The effects of different corrugation shapes on the improvement of antenna gain and front-to-back ratio (F-to-B ratio) are investigated. To demonstrate the validity of the design, the prototypes of TSA without and with corrugation are fabricated and measured. The results show good agreement between simulation and measurement.

A three-dimensional algebraic grid generation scheme for gas turbine combustors with inclined slots

Science.gov (United States)

Yang, S. L.; Cline, M. C.; Chen, R.; Chang, Y. L.

1993-01-01

A 3D algebraic grid generation scheme is presented for generating the grid points inside gas turbine combustors with inclined slots. The scheme is based on the 2D transfinite interpolation method. Since the scheme is a 2D approach, it is very efficient and can easily be extended to gas turbine combustors with either dilution hole or slot configurations. To demonstrate the feasibility and the usefulness of the technique, a numerical study of the quick-quench/lean-combustion (QQ/LC) zones of a staged turbine combustor is given. Preliminary results illustrate some of the major features of the flow and temperature fields in the QQ/LC zones. Formation of co- and counter-rotating bulk flow and shape temperature fields can be observed clearly, and the resulting patterns are consistent with experimental observations typical of the confined slanted jet-in-cross flow. Numerical solutions show the method to be an efficient and reliable tool for generating computational grids for analyzing gas turbine combustors with slanted slots.

A Universal Vacant Parking Slot Recognition System Using Sensors Mounted on Off-the-Shelf Vehicles

Directory of Open Access Journals (Sweden)

Jae Kyu Suhr

2018-04-01

Full Text Available An automatic parking system is an essential part of autonomous driving, and it starts by recognizing vacant parking spaces. This paper proposes a method that can recognize various types of parking slot markings in a variety of lighting conditions including daytime, nighttime, and underground. The proposed method can readily be commercialized since it uses only those sensors already mounted on off-the-shelf vehicles: an around-view monitor (AVM system, ultrasonic sensors, and in-vehicle motion sensors. This method first detects separating lines by extracting parallel line pairs from AVM images. Parking slot candidates are generated by pairing separating lines based on the geometric constraints of the parking slot. These candidates are confirmed by recognizing their entrance positions using line and corner features and classifying their occupancies using ultrasonic sensors. For more reliable recognition, this method uses the separating lines and parking slots not only found in the current image but also found in previous images by tracking their positions using the in-vehicle motion-sensor-based vehicle odometry. The proposed method was quantitatively evaluated using a dataset obtained during the day, night, and underground, and it outperformed previous methods by showing a 95.24% recall and a 97.64% precision.

Design of a Short/Open-Ended Slot Antenna with Capacitive Coupling Feed Strips for Hepta-Band Mobile Application

Directory of Open Access Journals (Sweden)

Kyoseung Keum

2018-01-01

Full Text Available In this paper, a planar printed hybrid short/open-ended slot antenna with capacitive coupling feed strips is proposed for hepta-band mobile applications. The proposed antenna is comprised of a slotted ground plane on the top plane and two capacitive coupling feed strips with a chip inductor on the bottom plane. At the low frequency band, the short-ended long slot fed by strip 1 generates its half-wavelength resonance mode, whereas the T-shaped open ended slot fed by strip 2 generates its quarter-wavelength resonance mode for the high frequency band. The antenna provides a wide bandwidth covering GSM850/GSM900/DCS/PCS/UMTS/LTE2300/LTE2500 operation bands. Moreover, the antenna occupies a small volume of 15 mm × 50 mm × 1 mm. The operating principle of the proposed antenna and the simulation/measurement results are presented and discussed.

Altering the "Near-Miss" Effect in Slot Machine Gamblers

Science.gov (United States)

Dixon, Mark R.; Nastally, Becky L.; Jackson, James E.; Habib, Reza

2009-01-01

This study investigated the potential for recreational gamblers to respond as if certain types of losing slot machine outcomes were actually closer to a win than others (termed the "near-miss effect"). Exposure to conditional discrimination training and testing disrupted this effect for 10 of the 16 participants. These 10 participants demonstrated…

Small slot waveguide rings for on-chip quantum optical circuits.

Science.gov (United States)

Rotenberg, Nir; Türschmann, Pierre; Haakh, Harald R; Martin-Cano, Diego; Götzinger, Stephan; Sandoghdar, Vahid

2017-03-06

Nanophotonic interfaces between single emitters and light promise to enable new quantum optical technologies. Here, we use a combination of finite element simulations and analytic quantum theory to investigate the interaction of various quantum emitters with slot-waveguide rings. We predict that for rings with radii as small as 1.44 μm, with a Q-factor of 27,900, near-unity emitter-waveguide coupling efficiencies and emission enhancements on the order of 1300 can be achieved. By tuning the ring geometry or introducing losses, we show that realistic emitter-ring systems can be made to be either weakly or strongly coupled, so that we can observe Rabi oscillations in the decay dynamics even for micron-sized rings. Moreover, we demonstrate that slot waveguide rings can be used to directionally couple emission, again with near-unity efficiency. Our results pave the way for integrated solid-state quantum circuits involving various emitters.

A Minimax Network Flow Model for Characterizing the Impact of Slot Restrictions

Science.gov (United States)

Lee, Douglas W.; Patek, Stephen D.; Alexandrov, Natalia; Bass, Ellen J.; Kincaid, Rex K.

2010-01-01

This paper proposes a model for evaluating long-term measures to reduce congestion at airports in the National Airspace System (NAS). This model is constructed with the goal of assessing the global impacts of congestion management strategies, specifically slot restrictions. We develop the Minimax Node Throughput Problem (MINNTHRU), a multicommodity network flow model that provides insight into air traffic patterns when one minimizes the worst-case operation across all airports in a given network. MINNTHRU is thus formulated as a model where congestion arises from network topology. It reflects not market-driven airline objectives, but those of a regulatory authority seeking a distribution of air traffic beneficial to all airports, in response to congestion management measures. After discussing an algorithm for solving MINNTHRU for moderate-sized (30 nodes) and larger networks, we use this model to study the impacts of slot restrictions on the operation of an entire hub-spoke airport network. For both a small example network and a medium-sized network based on 30 airports in the NAS, we use MINNTHRU to demonstrate that increasing the severity of slot restrictions increases the traffic around unconstrained hub airports as well as the worst-case level of operation over all airports.

CFD Analysis of a Centrifugal Fan for Performance Enhancement using Converging Boundary Layer Suction Slots

OpenAIRE

K. Vasudeva Karanth; N. Yagnesh Sharma

2009-01-01

Generally flow behavior in centrifugal fan is observed to be in a state of instability with flow separation zones on suction surface as well as near the front shroud. Overall performance of the diffusion process in a centrifugal fan could be enhanced by judiciously introducing the boundary layer suction slots. With easy accessibility of CFD as an analytical tool, an extensive numerical whole field analysis of the effect of boundary layer suction slots in discrete regions ...

Slot-type pickup/kicker for AA stochastic cooling

CERN Multimedia

1979-01-01

A "slotted transmission line" was used for both pickups and kickers of the stochastic cooling systems of the AA. They served for the cooling of the high-density antiproton stack, in momentum and both transverse planes. In the beginning, in a single band, 1-2 GHz, later in 2 bands, 2-4 and 4-8 GHz. View down the centre of a pickup or kicker. See also 7906189, 7906190, 7906583.

Contribution of experimental fluid mechanics to the design of vertical slot fish passes

Directory of Open Access Journals (Sweden)

Wang R.W.

2010-02-01

Full Text Available This paper presents the main results of an experimental study of mean and turbulent characteristics of flow in a scale model of a vertical slot fish pass with varying width and slope (from 5% to 15%. Experimental hydraulic modelling was combined with the study of fish behaviour in the model. The discharge coefficient, which significantly affects the design of such facilities, varied from 0.67 to 0.89 and was strongly influenced by the slope. Two distinct flow patterns were observed, depending on the slope and the fish pass width. The point of transition between the two states was determined. Low velocity areas are likely resting zones for fish and particular attention was paid to evaluating these areas. Slope was found to affect both the volume of the low velocity zone, and the value of turbulent kinetic energy in these areas. The statistical characteristics of turbulent kinetic energy in the pools were linked primarily to the maximum velocity in the jet. An analysis of the behaviour of juvenile brown trout (Salmo trutta in the scale model clearly showed that the fish avoided the areas of high velocities in the jet, except at the slot itself where they took advantage of the jet’s non-stationary character. Low-velocity areas were not frequented uniformly by fish, which stayed most frequently in the zone located just downstream from the slot and behind the small side baffle. It is suggested that future studies might investigate lower pool-length to slot-width ratios, which might make it possible to increase the slope significantly and should also examine ways of improving hydraulic conditions for fish by carefully distributing obstacles in pools.

Laser Doppler vibrometry experiment on a piezo-driven slot synthetic jet in water

Directory of Open Access Journals (Sweden)

Broučková Zuzana

2015-01-01

Full Text Available The present study deals with a slot synthetic jet (SJ issuing from an actuator into quiescent surroundings and driven by a piezoceramic transducer. The actuator slot width was 0.36 mm, with a drive frequency proposed near the theoretical natural frequency of the actuator. The working fluid was water at room temperature. The present experiments used flow visualization (a laser-induced fluorescence technique and laser Doppler vibrometry methods. Flow visualization was used to identify SJ formation, to demonstrate its function, and to estimate SJ velocity. Laser Doppler vibrometry was used to quantify diaphragm displacement and refine operating parameters. Phase averaging yielded a spatial and temporal diaphragm deflection during the actuation period. Taking incompressibility and continuity into consideration, the velocity in the actuator slot and the Reynolds number of the SJ were evaluated as 0.21 m/s and 157, respectively. The present results confirmed a SJ actuator function at the resonance frequency of approximately 46 Hz, which corresponds closely with the theoretical evaluation. The laser Doppler vibrometry results corresponded closely with an estimation of SJ velocity by the present flow visualization.

Error Floor Analysis of Coded Slotted ALOHA over Packet Erasure Channels

DEFF Research Database (Denmark)

Ivanov, Mikhail; Graell i Amat, Alexandre; Brannstrom, F.

2014-01-01

We present a framework for the analysis of the error floor of coded slotted ALOHA (CSA) for finite frame lengths over the packet erasure channel. The error floor is caused by stopping sets in the corresponding bipartite graph, whose enumeration is, in general, not a trivial problem. We therefore ...... identify the most dominant stopping sets for the distributions of practical interest. The derived analytical expressions allow us to accurately predict the error floor at low to moderate channel loads and characterize the unequal error protection inherent in CSA.......We present a framework for the analysis of the error floor of coded slotted ALOHA (CSA) for finite frame lengths over the packet erasure channel. The error floor is caused by stopping sets in the corresponding bipartite graph, whose enumeration is, in general, not a trivial problem. We therefore...

[Measurement of plasma parameters in slot microplasma by optical emission spectrum].

Science.gov (United States)

Dong, Li-Fang; Lü, Ying-Hui; Liu, Wei-Yuan; Yue, Han; Lu, Ning; Li, Xin-Chun

2010-12-01

Slot microplasma was generated in argon and air mixture by using dielectric barrier discharge device with two parallel water electrodes. The molecular vibrational temperature, molecular rotational temperature and average electron energy of the slot plasma were studied by optical emission spectrum. The molecular vibrational temperature was calculated using the second positive system of nitrogen molecules ( C3 pi(u) --> B3 pi(g)). The molecular rotational temperature was calculated using the first negative system of nitrogen molecular ions ( B 2sigma(u)+ --> X sigma(g)+). The relative intensities of the first negative system of nitrogen molecular ions (391.4 nm) and nitrogen molecules in the excitation level (337.1 nm) emission spectrum line were measured for studying the variations of electron energy. It was found that the molecular vibrational temperature, molecular rotational temperature and average electron energy decrease with gas pressure increasing.

Microwave Backscatter-Based Wireless Temperature Sensor Fabricated by an Alumina-Backed Au Slot Radiation Patch.

Science.gov (United States)

Lu, Fei; Wang, Haixing; Guo, Yanjie; Tan, Qiulin; Zhang, Wendong; Xiong, Jijun

2018-01-16

A wireless and passive temperature sensor operating up to 800 °C is proposed. The sensor is based on microwave backscatter RFID (radio frequency identification) technology. A thin-film planar structure and simple working principle make the sensor easy to operate under high temperature. In this paper, the proposed high temperature sensor was designed, fabricated, and characterized. Here the 99% alumina ceramic with a dimension of 40 mm × 40 mm × 1 mm was prepared in micromechanics for fabrication of the sensor substrate. The metallization of the Au slot patch was realized in magnetron sputtering with a slot width of 2 mm and a slot length of 32 mm. The measured resonant frequency of the sensor at 25 °C is 2.31 GHz. It was concluded that the resonant frequency decreases with the increase in the temperature in range of 25-800 °C. It was shown that the average sensor sensitivity is 101.94 kHz/°C.

Linearly tapered slot antenna circular array for mobile communications

Science.gov (United States)

Simons, Rainee N.; Kelly, Eron; Lee, Richard Q.; Taub, Susan R.

1993-01-01

The design, fabrication and testing of a conformal K-band circular array is presented. The array consists of sixteen linearly tapered slot antennas (LTSA). It is fed by a 1:16 microstrip line power splitter via electromagnetic coupling. The array has an omni-directional pattern in the azimuth plane. In the elevation plane the beam is displaced above the horizon.

broadband, low sidelobe, zero height, slotted circular disk antenna

African Journals Online (AJOL)

of argument rr where J? = jwµ.(slot of the antenna can be obtained by substituting 'Tr', hack into the field equations. The results are given hy the ...

Creating New Child Care Slots in Mini Child Care Centers: Big Bang for the Buck in New Jersey.

Science.gov (United States)

Frankel, Arthur J.; And Others

1992-01-01

Small grants of $7,500 with technical assistance were offered to the child care community of New Jersey to either start or increase licensed capacity in mini-child care centers. Results of a subsequent analysis showed that 26 grantees created 481 new child care slots at an average cost of $561 per slot. (Author/SM)

The Effect of Slot-Code Optimization in Warehouse Order Picking

Directory of Open Access Journals (Sweden)

Andrea Fumi

2013-07-01

most appropriate material handling resource configuration. Building on previous work on the effect of slot-code optimization on travel times in single/dual command cycles, the authors broaden the scope to include the most general picking case, thus widening the range of applicability and realising former suggestions for future research.

Simple gambling or sophisticated gaming? : applying game analysis methods to modern video slot machine games

OpenAIRE

Leppäsalko, Tero

2017-01-01

Slot machine games have become the most popular form of gambling worldwide. In Finland, their pervasiveness in public spaces and popularity makes them one of the most common form of gaming. However, in game studies, gambling games are often regarded as borderline games due to the player’s lack of control. In this thesis I ask whether modern video slot machine games can be considered as games and if so, what similarities there are between them and contemporary video games. To find out if m...

The impact of different stator and rotor slot number combinations on iron losses of a three-phase induction motor at no-load

International Nuclear Information System (INIS)

Marcic, T.; Stumberger, B.; Stumberger, G.; Hadziselimovic, M.; Zagradisnik, I.

2008-01-01

The electromechanical characteristics of induction motors depend on the used stator and rotor slot combination. The correlation between the usage of different stator and rotor slot number combinations, magnetic flux density distributions, no-load iron losses and rated load winding over-temperatures for a specific induction motor is presented. The motor's magnetic field was analyzed by traces of the magnetic flux density vector, obtained by FEM. Post-processing of FE magnetic field solution was used for posterior iron loss calculation of the motor iron loss at no-load. The examined motor stator lamination had 36 semi-closed slots and the rotor laminations had 28, 33, 34, 44 and 46 semi-closed slots

On-chip broadband ultra-compact optical couplers and polarization splitters based on off-centered and non-symmetric slotted Si-wire waveguides

Science.gov (United States)

Haldar, Raktim; Mishra, V.; Dutt, Avik; Varshney, Shailendra K.

2016-10-01

In this work, we propose novel schemes to design on-chip ultra-compact optical directional couplers (DC) and broadband polarization beam splitters (PBS) based on off-centered and asymmetric dielectric slot waveguides, respectively. Slot dimensions and positions are optimized to achieve maximum coupling coefficients between two symmetric and non-symmetric slotted Si wire waveguides through overlap integral method. We observe >88% of enhancement in the coupling coefficients when the size-optimized slots are placed in optimal positions, with respect to the same waveguides with no slot. When the waveguides are parallel, in that case, a coupling length as short as 1.73 μm is accomplished for TM mode with the off-centered and optimized slots. This scheme enables us to design optical DC with very small footprint, L c ∼ 0.9 μm in the presence of S-bends. We also report a compact (L c ∼ 1.1 μm) on-chip broadband PBS with hybrid slots. Extinction ratios of 13 dB and 22.3 dB are realized with very low insertion loss (0.055 dB and 0.008 dB) for TM and TE modes at 1.55 μm, respectively. The designed PBS exhibits a bandwidth of 78 nm for the TM mode (C-and partial L-bands) and >100 nm for the TE mode (S + C + L wavelength bands). Such on-chip devices can be used to design compact photonic interconnects and quantum information processing units efficiently. We have also investigated the fabrication tolerances of the proposed devices and described the fabrication steps to realize such hybrid devices. Our results are in good agreement with 3D FDTD simulations.

Refractive index and temperature sensitivity characteristics of a micro-slot fiber Bragg grating.

Science.gov (United States)

Saffari, Pouneh; Yan, Zhijun; Zhou, Kaiming; Zhang, Lin

2012-07-10

Fabrication and characterization of a UV inscribed fiber Bragg grating (FBG) with a micro-slot liquid core is presented. Femtosecond (fs) laser patterning/chemical etching technique was employed to engrave a micro-slot with dimensions of 5.74 μm(h)×125 μm(w)×1388.72 μm(l) across the whole grating. The device has been evaluated for refractive index (RI) and temperature sensitivities and exhibited distinctive thermal response and RI sensitivity beyond the detection limit of reported fiber gratings. This structure has not just been RI sensitive, but also maintained the robustness comparing with the bare core FBGs and long-period gratings with the partial cladding etched off.

Performance evaluation of fractional-slot tubular permanent magnet machines with low space harmonics

Directory of Open Access Journals (Sweden)

Wang Jiabin

2015-12-01

Full Text Available This paper evaluates the perforamnce of fractional-slot per pole winding configurations for tubular permanent magnet (PM machines that can effectively eliminate the most undesirable space harmonics in a simple and cost-effective manner. The benefits of the proposed machine topology winding configurations are illustrated through comparison with 9-slot, 10-pole tubular PM machine developed for a free piston energy converter under the same specification and volumetric constraints. It has been shown that the proposed machine topology results in more than 7 times reduction in the eddy current loss in the mover magnets and supporting tube, and hence avoids potential problem of excessive mover temperature and risk of demagnetization.

Compact SOI optimized slot microring coupled phase-shifted Bragg grating resonator for sensing

Science.gov (United States)

Zhao, Chao Ying; Zhang, Lei; Zhang, Cheng Mei

2018-05-01

We propose a novel sensor structure composed of a slot microring and a phase-shifted sidewall Bragg gratings in a slot waveguide. We first present a theoretical analysis of transmission by using the transfer matrix. Then, the mode-field distributions of transmission spectrum obtained from 3D simulations based on FDTD method demonstrates that our sensor exhibit theoretical sensitivity of 297 . 13 nm / RIU, a minimum detection limit of 1 . 1 × 10-4 RIU, the maximum extinction ratio of 20 dB, the quality factor of 2 × 103 and a compact dimension-theoretical structure of 15 μm × 8 . 5 μm. Finally, the sensor's performance is simulated for NaCl solution.

Dual Circularly Polarized Omnidirectional Antenna with Slot Array on Coaxial Cylinder

Directory of Open Access Journals (Sweden)

Bin Zhou

2015-01-01

Full Text Available A dual circularly polarized (CP omnidirectional antenna based on slot array in coaxial cylinder structure is presented in this paper. It is constructed by perpendicular slot pairs around and along the axis of the coaxial cylinder to realize the omnidirectional CP property, and two ports are assigned in its two sides as left hand circularly polarized (LHCP port and right hand circularly polarized (RHCP port, respectively. The proposed antenna achieves a bandwidth of 16.4% ranging from 5.05 to 5.95 GHz with an isolation higher than 15 dB between the two CP ports, and the return loss (RL is higher than 10 dB within the bandwidth in both of the two ports. From the measured results, the average axial ratio (AR of the proposed antenna in omnidirectional plane is lower than 1.5 dB.

Effect of pole number and slot number on performance of dual rotor permanent magnet wind power generator using ferrite magnets

Directory of Open Access Journals (Sweden)

Peifeng Xu

2017-05-01

Full Text Available Dual rotor permanent magnet (DRPM wind power generator using ferrite magnets has the advantages of low cost, high efficiency, and high torque density. How to further improve the performance and reduce the cost of the machine by proper choice of pole number and slot number is an important problem to be solved when performing preliminarily design a DRPM wind generator. This paper presents a comprehensive performance comparison of a DRPM wind generator using ferrite magnets with different slot and pole number combinations. The main winding factors are calculated by means of the star of slots. Under the same machine volume and ferrite consumption, the flux linkage, back-electromotive force (EMF, cogging torque, output torque, torque pulsation, and losses are investigated and compared using finite element analysis (FEA. The results show that the slot and pole number combinations have an important impact on the generator properties.

Influence of bracket-slot design on the forces released by superelastic nickel-titanium alignment wires in different deflection configurations.

Science.gov (United States)

Nucera, Riccardo; Gatto, Elda; Borsellino, Chiara; Aceto, Pasquale; Fabiano, Francesca; Matarese, Giovanni; Perillo, Letizia; Cordasco, Giancarlo

2014-05-01

To evaluate how different bracket-slot design characteristics affect the forces released by superelastic nickel-titanium (NiTi) alignment wires at different amounts of wire deflection. A three-bracket bending and a classic-three point bending testing apparatus were used to investigate the load-deflection properties of one superelastic 0.014-inch NiTi alignment wire in different experimental conditions. The selected NiTi archwire was tested in association with three bracket systems: (1) conventional twin brackets with a 0.018-inch slot, (2) a self-ligating bracket with a 0.018-inch slot, and (3) a self-ligating bracket with a 0.022-inch slot. Wire specimens were deflected at 2 mm and 4 mm. Use of a 0.018-inch slot bracket system, in comparison with use of a 0.022-inch system, increases the force exerted by the superelastic NiTi wires at a 2-mm deflection. Use of a self-ligating bracket system increases the force released by NiTi wires in comparison with the conventional ligated bracket system. NiTi wires deflected to a different maximum deflection (2 mm and 4 mm) release different forces at the same unloading data point (1.5 mm). Bracket design, type of experimental test, and amount of wire deflection significantly affected the amount of forces released by superelastic NiTi wires (Pwire's load during alignment.

Coplanar Waveguide Fed Compact Wide Circular-Slotted Antenna for Wi-Fi/WiMAX Applications

Directory of Open Access Journals (Sweden)

M. Samsuzzaman

2014-01-01

Full Text Available A coplanar waveguide (CPW fed printing and wide circular slotted, dual band antenna for Wi-Fi/WiMAX applications are presented. The antenna mainly encompasses a ground with a wide circular slot in the centre, a rectangular feeding strip, and two pairs of symmetric planar inverted L (SPIL strips connecting with the slotted ground. The tuning effects of the rectangular patch, ground size, and SPIL strips to the resonance and matching condition are examined by HFSS and the prototype is fabricated and measured. The simulation and experimental results show that the antenna has an impedance bandwidth with −10 dB reflection coefficients 600 MHz (3.26–3.86 GHz, lower band and 1040 MHz (5.02–6.26 GHz, upper band, which can cover both the Wi-Fi 5.2/5.5/5.8 GHz and WiMAX 3.3/3.5/3.7/5.8 GHz bands. Moreover, a stable omnidirectional radiation pattern and average peak gain for lower band 3.23 dB and upper band 5.93 dB have been achieved, respectively.

Correction of Beam Distortion in Negative Hydrogen Ion Source with Multi-Slot Grounded Grid

International Nuclear Information System (INIS)

Tsumori, Katsuyoshi; Kaneko, Osamu; Takeiri, Yasuhiko; Oka, Yoshihide; Osakabe, Masaki; Ikeda, Katsunori; Nagaoka, Kenichi; Kawamoto, Toshikazu; Asano, Eiji; Sato, Mamoru; Kondo, Tomoki; Watanabe, Junko; Asano, Shiro; Suzuki, Yasuo

2005-01-01

The new beam accelerator with multi-slot grounded grid (MSGG) has been developed to increase the port-through power into large helical device (LHD). Using the accelerator, the maximum power of 5.7 MW was achieved at the beam energy of 186 keV in the beam injection to LHD plasma last year. Although the port-through power increased compared with conventional accelerators with multi-hole grounded grid (MHGG), the accelerator with the MSGG includes a disadvantage of bi-focal condition in parallel and perpendicular direction to the long side of the slots. When the beam width in one of those directions gets narrower, the width in another direction becomes wider. This disadvantage includes the loss of beam port-through power and induces internal damages in neutral beam line. In order to reduce the disadvantage, an experiment has been done using a small-scaled negative ion source with racetrack-shaped apertures for the steering grid installed at beam upstream of the MSGG. By applying the racetrack apertures to the accelerator, it is observed that the beam widths in the parallel and perpendicular directions to the slot long side have almost the same focal condition to obtain minimal beam widths

Report for slot cutter proof-of-principle test, Buried Waste Containment System project. Revision 1

International Nuclear Information System (INIS)

1998-01-01

Several million cubic feet of hazardous and radioactive waste was buried in shallow pits and trenches within many US Department of Energy (US DOE) sites. The pits and trenches were constructed similarly to municipal landfills with both stacked and random dump waste forms such as barrels and boxes. Many of the hazardous materials in these waste sites are migrating into groundwater systems through plumes and leaching. On-site containment is one of the options being considered for prevention of waste migration. This report describes the results of a proof-of-principle test conducted to demonstrate technology for containing waste. This proof-of-principle test, conducted at the RAHCO International, Inc., facility in the summer of 1997, evaluated equipment techniques for cutting a horizontal slot beneath an existing waste site. The slot would theoretically be used by complementary equipment designed to place a cement barrier under the waste. The technology evaluated consisted of a slot cutting mechanism, muck handling system, thrust system, and instrumentation. Data were gathered and analyzed to evaluate the performance parameters

Report for slot cutter proof-of-principle test, Buried Waste Containment System project. Revision 1

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-05-21

Several million cubic feet of hazardous and radioactive waste was buried in shallow pits and trenches within many US Department of Energy (US DOE) sites. The pits and trenches were constructed similarly to municipal landfills with both stacked and random dump waste forms such as barrels and boxes. Many of the hazardous materials in these waste sites are migrating into groundwater systems through plumes and leaching. On-site containment is one of the options being considered for prevention of waste migration. This report describes the results of a proof-of-principle test conducted to demonstrate technology for containing waste. This proof-of-principle test, conducted at the RAHCO International, Inc., facility in the summer of 1997, evaluated equipment techniques for cutting a horizontal slot beneath an existing waste site. The slot would theoretically be used by complementary equipment designed to place a cement barrier under the waste. The technology evaluated consisted of a slot cutting mechanism, muck handling system, thrust system, and instrumentation. Data were gathered and analyzed to evaluate the performance parameters.

A High-gain and Low-scattering Waveguide Slot Antenna of Artificial Magnetic Conductor Octagonal Ring Arrangement

Directory of Open Access Journals (Sweden)

X. Liu

2016-04-01

Full Text Available A novel design of high-gain and low-scattering waveguide slot antenna is proposed in this paper. Firstly the scattering pattern of artificial magnetic conductor (AMC composite surface is estimated by array factor analysis method. The comparison between octagonal ring arrangement and chessboard arrangement proves that the former arrangement has the characteristic of diffuseness-like and expands the bandwidth of radar cross section (RCS reduction. Secondly, the metal surface of waveguide slot antenna (WSA is replaced by the octagonal ring arrangement composite surface (ORACS. The gain is improved because of spurious radiation units which are around the slot. At the same time using the phase cancellation principle, a backscatter null achieves RCS reduction in the vertical direction. Experimental results show that the novel antenna after loading with the ORACS, the gain is improved by 5dB; the bandwidth of RCS reduction (reduction greater than 10dB is 5.24-5.92 GHz.

Spontaneous decay of a single quantum dot coupled to a metallic slot waveguide in the presence of leaky plasmonic modes

DEFF Research Database (Denmark)

Chen, Yuntian; Gregersen, Niels; Nielsen, Torben Roland

2010-01-01

in which the metallic slot waveguide is embedded. Compared to the ideal case of a homogenous dielectric environment, the coupling efficiency of an emitter to a metallic slot waveguide is significantly reduced. We attribute the reduction to the coupling to leaky plasmonic modes. By increasing the refractive...

Non-similar solutions for unsteady flow over a yawed cylinder with non-uniform mass transfer through a slot

Directory of Open Access Journals (Sweden)

G. Revathi

2014-12-01

Full Text Available Non-similar solutions are found numerically to a system of coupled non-linear partial differential equations indicating, unsteady laminar water boundary layer flow over yawed cylinder using implicit finite difference scheme along with Quasi-linearization technique. The fluid properties such as viscosity and Prandtl number are considered as an inverse function of temperature. Unsteadiness is caused by upstream velocity in and directions and non-uniform mass transfer (suction/injection which is applied through slot on the surface of the geometry. The effect of yaw angle, variable fluid properties and non-uniform mass transfer on skin friction and heat transfer coefficients is analyzed. It is found that non-uniform slot suction and downstream movement of the slot cause the point of vanishing skin friction moves downstream, but non-uniform slot injection produces the opposite result of that corresponding to the suction case. When the yaw angle increases, both the skin friction coefficient in the – direction and the heat transfer coefficient decrease but the skin friction coefficient in the – direction increases for all times. The effect of the yaw angle is very little on the point of vanishing skin friction.

Label-free optical biosensing with slot-waveguides.

Science.gov (United States)

Barrios, Carlos A; Bañuls, María José; González-Pedro, Victoria; Gylfason, Kristinn B; Sánchez, Benito; Griol, Amadeu; Maquieira, A; Sohlström, H; Holgado, M; Casquel, R

2008-04-01

We demonstrate label-free molecule detection by using an integrated biosensor based on a Si(3)N(4)/SiO(2) slot-waveguide microring resonator. Bovine serum albumin (BSA) and anti-BSA molecular binding events on the sensor surface are monitored through the measurement of resonant wavelength shifts with varying biomolecule concentrations. The biosensor exhibited sensitivities of 1.8 and 3.2 nm/(ng/mm(2)) for the detection of anti-BSA and BSA, respectively. The estimated detection limits are 28 and 16 pg/mm(2) for anti-BSA and BSA, respectively, limited by wavelength resolution.

D0 Silicon Upgrade: CTF Front End Crate J2/J3 Backplane Specification

International Nuclear Information System (INIS)

Baert, Mark

1995-01-01

GENERAL PHYSICAL LAYOUT: (1) The backplane is comprised of 2 identical sections, the upper half designated J1, and the lower half designated j3; (2) For each section, there are a total of 16 slots, designated 1 through 16, from left to right; (3) Odd numbered slots are left handed (Connectors to the left of the card), these slots utilize inverse DIN connectors; (4) Even numbered slots are right handed (Connectors to the right of the card), these slots utilize standard DIN connectors; (5) There are 2 60 pin daisy-chain headers associated with each section, 3M part number 3597-6003; (6) The headers associated with the J2 (upper) section are designated J2CHAINR and J2CHAINL; (7) The headers associated with the J3 (lower) section are designated J3CHAINL and J3CHAINR; and (8) Mechanical layout presented in drawing number 3823.113-MD-330045. TRIGGER SIGNALS: (1) There are 21 trigger signal which originate from a given slot and are routed to the slot immediately to the left and 21 trigger signals which originate from a given slot and are routed to the slot immediately to the right; (2) There are 21 trigger signals which originate from the slot immediately to the left of a given slot and 21 trigger signals which originate from the slot immediately to the right a given slot; (3) The signal are designated TRIGjk-n, when j is the source slot, k is the destination slot, and n is the signal number; (4) These signals shall be implemented as 100 ohm microstip above ground plane; and (5) No terminations. DC POWER: (1) Each slot is supplied with DC power on the connector pins designated as VCC and GND; (2) VCC and GND originates at rear of the backplane via press-in power terminals, their locations are shown in drawing number 3823.113-MD-330045; (3) Power shall be bypassed at 2 locations with a 10uF tantalum capacitor in parallel with a .01uF 100V ceramic capacitor; and (4) The total ampacity supplied by each DIN connector is 3.6 amps.

26 CFR 7.6041-1 - Return of information as to payments of winnings from bingo, keno, and slot machines.

Science.gov (United States)

2010-04-01

... winnings from bingo, keno, and slot machines. 7.6041-1 Section 7.6041-1 Internal Revenue INTERNAL REVENUE..., keno, and slot machines. (a) In general. On or after May 1, 1977, every person engaged in a trade or... machine play or of $1,500 or more from a keno game shall make an information return with respect to such...

Nano-polarization-converter based on magnetic plasmon resonance excitation in an L-shaped slot antenna.

Science.gov (United States)

Yang, Jing; Zhang, Jiasen

2013-04-08

We propose a nano-polarization-converter made of a resonant L-shaped slot antenna in a gold film and study its optical properties using the finite-difference time-domain method. Phase retardation between the fast and slow axes of the nano-polarization-converter originates from the simultaneous excitation of both single-surface first-order magnetic plasmon resonance mode and second-order magnetic plasmon resonance mode at the working wavelength. By adjusting the size of the slot antenna, which is still much smaller than the wavelength, the working wavelength can be tuned within a large wavelength range.

Optical datacenter network employing slotted (TDMA) operation for dynamic resource allocation

Science.gov (United States)

Bakopoulos, P.; Tokas, K.; Spatharakis, C.; Patronas, I.; Landi, G.; Christodoulopoulos, K.; Capitani, M.; Kyriakos, A.; Aziz, M.; Reisis, D.; Varvarigos, E.; Zahavi, E.; Avramopoulos, H.

2018-02-01

The soaring traffic demands in datacenter networks (DCNs) are outpacing progresses in CMOS technology, challenging the bandwidth and energy scalability of currently established technologies. Optical switching is gaining traction as a promising path for sustaining the explosive growth of DCNs; however, its practical deployment necessitates extensive modifications to the network architecture and operation, tailored to the technological particularities of optical switches (i.e. no buffering, limitations in radix size and speed). European project NEPHELE is developing an optical network infrastructure that leverages optical switching within a software-defined networking (SDN) framework to overcome the bandwidth and energy scaling challenges of datacenter networks. An experimental validation of the NEPHELE data plane is reported based on commercial off-the-shelf optical components controlled by FPGA boards. To facilitate dynamic allocation of the network resources and perform collision-free routing in a lossless network environment, slotted operation is employed (i.e. using time-division multiple-access - TDMA). Error-free operation of the NEPHELE data plane is verified for 200 μs slots in various scenarios that involve communication between Ethernet hosts connected to custom-designed top-of-rack (ToR) switches, located in the same or in different datacenter pods. Control of the slotted data plane is obtained through an SDN framework comprising an OpenDaylight controller with appropriate add-ons. Communication between servers in the optical-ToR is demonstrated with various routing scenarios, concerning communication between hosts located in the same rack or in different racks, within the same or different datacenter pods. Error-free operation is confirmed for all evaluated scenarios, underpinning the feasibility of the NEPHELE architecture.

Optical slotted circuit switched network: a bandwidth efficient alternative to wavelength-routed network

Science.gov (United States)

Li, Yan; Collier, Martin

2007-11-01

Wavelength-routed networks have received enormous attention due to the fact that they are relatively simple to implement and implicitly offer Quality of Service (QoS) guarantees. However, they suffer from a bandwidth inefficiency problem and require complex Routing and Wavelength Assignment (RWA). Most attempts to address the above issues exploit the joint use of WDM and TDM technologies. The resultant TDM-based wavelength-routed networks partition the wavelength bandwidth into fixed-length time slots organized as a fixed-length frame. Multiple connections can thus time-share a wavelength and the grooming of their traffic leads to better bandwidth utilization. The capability of switching in both wavelength and time domains in such networks also mitigates the RWA problem. However, TMD-based wavelength-routed networks work in synchronous mode and strict synchronization among all network nodes is required. Global synchronization for all-optical networks which operate at extremely high speed is technically challenging, and deploying an optical synchronizer for each wavelength involves considerable cost. An Optical Slotted Circuit Switching (OSCS) architecture is proposed in this paper. In an OSCS network, slotted circuits are created to better utilize the wavelength bandwidth than in classic wavelength-routed networks. The operation of the protocol is such as to avoid the need for global synchronization required by TDM-based wavelength-routed networks.

Excitation of spin waves in BiFeO3 multiferroic film by the slot line transducer

Science.gov (United States)

Korneev, V. I.; Popkov, A. F.; Solov'yov, S. V.

2018-01-01

Analysis of the efficiency of magnetoelectric excitation of spin-waves in BiFeO3 multiferroic films by a slot line is performed based on the solution of dynamic Ginzburg-Landau equations for the antiferromagnetic vector. The excitation efficiency is determined by the magnitude of the conversion coefficient of the electromagnetic wave to the spin wave by the slot line transducer or in other words, losses on conversion in the slot line. Calculations are made for a homogeneous antiferromagnetic state of the multiferroic in the presence of a sufficiently large magnetic field and for a spatially modulated spin state (SMSS) at zero magnetic field. It is shown that in the case of a homogeneous antiferromagnetic state, the losses on the excitation of spin waves exceed the excitation efficiency in the SMSS state; however, as the frequency approaches the spin excitation gap, it falls and becomes lower than in the SMSS state. Spin wave excitation in the presence of antiferromagnetic cycloid strongly depends on the relation of the slot width of the transducer to the cycloid periodicity and on the magnitude of the shift of the position of the transducer along the cycloid on its period. The usage of multiferroics for delay lines in the considered frequency range from 100 to 600 GHz requires significant reduction in conversion and propagation losses. More promising seems multiferroic usage in phase shifters and switches for this range.

Measurements on Buoyant Jet Flows from a Ceiling-Mounted Slot Diffuser

DEFF Research Database (Denmark)

Nielsen, Peter V.; Möller, Åke T. A.

Ceiling-mounted slot diffusers in ventilated rooms will often generate a flow of the wall jet type. The jet follows the ceiling, entrains air from the occupied zone and generates a recirculating flow in the whole room. This paper will deal with the flow in the ceiling region. The wall jet flow...

Polymer solar cell modules prepared using roll-to-roll methods: Knife-over-edge coating, slot-die coating and screen printing

DEFF Research Database (Denmark)

Krebs, Frederik C

2009-01-01

was patterned into stripes and juxtaposed with the ITO layer. The fourth layer comprised screen-printed or slot-die-coated PEDOT:PSS and the fifth and the final layer comprised a screen-printed or slot-die-coated silver electrode. The final module dimensions were 28 cm×32 cm and presented four individual solar...

CPW-fed Circularly Polarized Slot Antenna with Small Gap and Stick-shaped Shorted Strip for UHF FRID Readers

Science.gov (United States)

Pan, Chien-Yuan; Su, Chum-Chieh; Yang, Wei-Lin

2018-04-01

A new circularly polarized (CP) slot antenna with a small gap and a stick-shaped shorted strip is presented. The proposed antenna has a sufficient bandwidth for ultrahigh frequency (UHF) radio-frequency identification (RFID) reader applications. The antenna structure consists of a rectangular slot with a small gap, a stick-shaped shorted strip and a 50 Ω coplanar waveguide (CPW) feedline with an asymmetrical ground plane. By using the stick -shaped shorted strip to disturb magnetic current distribution on the slot, the CP radiation can be generated. The measured results demonstrate that the proposed antenna can reach a 10 dB return loss impedance bandwidth of 14.1 % (894-1030 MHz) and a 3 dB axial ratio (AR) bandwidth of 6.4 % (910-970 MHz). The whole antenna size is 80 × 80 × 1.6 mm3.

Brain cells in the avian 'prefrontal cortex' code for features of slot-machine-like gambling.

Directory of Open Access Journals (Sweden)

Damian Scarf

2011-01-01

Full Text Available Slot machines are the most common and addictive form of gambling. In the current study, we recorded from single neurons in the 'prefrontal cortex' of pigeons while they played a slot-machine-like task. We identified four categories of neurons that coded for different aspects of our slot-machine-like task. Reward-Proximity neurons showed a linear increase in activity as the opportunity for a reward drew near. I-Won neurons fired only when the fourth stimulus of a winning (four-of-a-kind combination was displayed. I-Lost neurons changed their firing rate at the presentation of the first nonidentical stimulus, that is, when it was apparent that no reward was forthcoming. Finally, Near-Miss neurons also changed their activity the moment it was recognized that a reward was no longer available, but more importantly, the activity level was related to whether the trial contained one, two, or three identical stimuli prior to the display of the nonidentical stimulus. These findings not only add to recent neurophysiological research employing simulated gambling paradigms, but also add to research addressing the functional correspondence between the avian NCL and primate PFC.

A Design of Wide Band and Wide Beam Cavity-Backed Slot Antenna Array with Slant Polarization

Directory of Open Access Journals (Sweden)

Huiying Qi

2016-01-01

Full Text Available Design of antenna array under the limitation of restricted size is a challenging problem. Cavity-backed slot antenna is widely used because of its advantages of small size, wide band, and wide beam. In this paper, a design of wide band and wide beam cavity-backed slot antenna array with the slant polarization is proposed. To obtain wide band and wide beam with limited size, the inverted microstrip-fed cavity-backed slot antenna (IMF-CBSA is adopted as the element of 1 × 4 antenna array. The slant polarized antennas and their feeding networks are adopted because of their simple structures. The performance of the proposed antenna array is verified by the simulations and experiments. The measured VSWR < 2 bandwidth is 55% at the center frequency 21.8 GHz, and the gain is larger than 12.2 dB. Experimental results demonstrate that the proposed design achieves wide band and beam with the size of 68 mm × 56 mm × 14.5 mm.

Iodine-induced stress corrosion cracking of fixed deflection stressed slotted rings of Zircaloy fuel cladding

International Nuclear Information System (INIS)

Sejnoha, R.; Wood, J.C.

1978-01-01

Stress corrosion cracking of Zircaloy fuel cladding by fission products is thought to be an important mechanism influencing power ramping defects of water-reactor fuels. We have used the fixed-deflection stressed slotted-ring technique to demonstrate cracking. The results show both the sensitivity and limitations of the stressed slotted-ring method in determining the responses of tubing to stress corrosion cracking. They are interpreted in terms of stress relaxation behavior, both on a microscopic scale for hydrogen-induced stress-relief and on a macroscopic scale for stress-time characteristics. Analysis also takes account of nonuniform plastic deformation during loading and residual stress buildup on unloading. 27 refs

Low Average Sidelobe Slot Array Antennas for Radiometer Applications

Science.gov (United States)

Rengarajan, Sembiam; Zawardzki, Mark S.; Hodges, Richard E.

2012-01-01

In radiometer applications, it is required to design antennas that meet low average sidelobe levels and low average return loss over a specified frequency bandwidth. It is a challenge to meet such specifications over a frequency range when one uses resonant elements such as waveguide feed slots. In addition to their inherent narrow frequency band performance, the problem is exacerbated due to modeling errors and manufacturing tolerances. There was a need to develop a design methodology to solve the problem. An iterative design procedure was developed by starting with an array architecture, lattice spacing, aperture distribution, waveguide dimensions, etc. The array was designed using Elliott s technique with appropriate values of the total slot conductance in each radiating waveguide, and the total resistance in each feed waveguide. Subsequently, the array performance was analyzed by the full wave method of moments solution to the pertinent integral equations. Monte Carlo simulations were also carried out to account for amplitude and phase errors introduced for the aperture distribution due to modeling errors as well as manufacturing tolerances. If the design margins for the average sidelobe level and the average return loss were not adequate, array architecture, lattice spacing, aperture distribution, and waveguide dimensions were varied in subsequent iterations. Once the design margins were found to be adequate, the iteration was stopped and a good design was achieved. A symmetric array architecture was found to meet the design specification with adequate margin. The specifications were near 40 dB for angular regions beyond 30 degrees from broadside. Separable Taylor distribution with nbar=4 and 35 dB sidelobe specification was chosen for each principal plane. A non-separable distribution obtained by the genetic algorithm was found to have similar characteristics. The element spacing was obtained to provide the required beamwidth and close to a null in the E

Radio-Frequency design of a Lower Hybrid Slotted Waveguide Antenna.

Czech Academy of Sciences Publication Activity Database

Helou, W.; Goniche, M.; Hillairet, J.; Žáček, František; Achard, J.; Adámek, Jiří; Bogár, Ondrej; Mollard, P.; Pascal, J.-Y.; Poli, S.; Šesták, David; Volpe, R.; Zajac, Jaromír

2017-01-01

Roč. 123, November (2017), s. 223-227 ISSN 0920-3796. [SOFT 2016: Symposium on Fusion Technology /29./. Prague, 05.09.2016-09.09.2016] Institutional support: RVO:61389021 Keywords : Lower Hybrid Current Drive * Slotted Waveguide Antenna * Phased arrays Subject RIV: JF - Nuclear Energetics OBOR OECD: Nuclear related engineering Impact factor: 1.319, year: 2016 https://www.sciencedirect.com/science/article/pii/S0920379617304076

An analysis of switching and non-switching slot machine player behaviour.

Science.gov (United States)

Coates, Ewan; Blaszczynski, Alex

2013-12-01

Learning theory predicts that, given the repeated choice to bet between two concurrently available slot machines, gamblers will learn to bet more money on the machine with higher expected return (payback percentage) or higher win probability per spin (volatility). The purpose of this study was to investigate whether this occurs when the two machines vary orthogonally on payback percentage and volatility. The sample comprised 52 first year psychology students (mean age = 20.3 years, 20 females, 32 males) who had played a gaming machine at least once in the previous 12 months. Participants were administered a battery of questionnaires designed to assess level of knowledge on the characteristics and operation of poker machines, frequency of poker machine play in the past 12 months, personality traits of impulsivity and capacity for cognitive reflection, and gambling beliefs. For the experimental task, participants were instructed to play on two PC-simulated electronic gaming machines (EGMs or slot machines) that differed on payback percentage and volatility, with the option of freely switching between EGMs after a practice phase. Results indicated that participants were able to easily discriminate between machines and manifested a preference to play machines offering higher payback or volatility. These findings diverged from previous findings of no preference for play on higher payback/volatility machines, potentially due to of the current study's absence of the option to make multi-line and multi-credit bets. It was concluded that return rate parameters like payback percentage and volatility strongly influenced slot machine preference in the absence of betting options like multi-line bets, though more research is needed to determine the effects of such betting options on player distribution of money between multiple EGMs.

Process and device for the ultrasonic testing of slotted screws screwed into a head of a nuclear reactor fuel element for cracks

International Nuclear Information System (INIS)

Scharpenberg, R.

1986-01-01

To achieve correct echo signals, a test head is set separately on each area limited by a slot of the top of the slotted screw and the screw head is ultrasonically sounded in the direction of the suspected cracks. (orig./HP) [de

A new method for the design of slot antenna arrays: Theory and experiment

KAUST Repository

Clauzier, Sebastien; Mikki, Said M.; Shamim, Atif; Antar, Yahia M. M.

2016-01-01

technique combines basic radiation theory and waveguide propagation theory in a novel analytical model that allows the prediction of the radiation characteristics of generic slots without the need to perform full-wave numerical solution. The analytical model

Different optical properties in different periodic slot cavity geometrical morphologies

Science.gov (United States)

Zhou, Jing; Shen, Meng; Du, Lan; Deng, Caisong; Ni, Haibin; Wang, Ming

2016-09-01

In this paper, optical properties of two-dimensional periodic annular slot cavity arrays in hexagonal close-packing on a silica substrate are theoretically characterized by finite difference time domain (FDTD) simulation method. By simulating reflectance spectra, electric field distribution, and charge distribution, we confirm that multiple cylindrical surface plasmon resonances can be excited in annular inclined slot cavities by linearly polarized light, in which the four reflectance dips are attributed to Fabry-Perot cavity resonances in the coaxial cavity. A coaxial waveguide mode TE11 will exist in these annular cavities, and the wavelengths of these reflectance dips are effectively tailored by changing the geometrical pattern of slot cavity and the dielectric materials filled in the cavities. These resonant wavelengths are localized in annular cavities with large electric field enhancement and dissipate gradually due to metal loss. The formation of an absorption peak can be explained from the aspect of phase matching conditions. We observed that the proposed structure can be tuned over the broad spectral range of 600-4000 nm by changing the outer and inner radii of the annular gaps, gap surface topography. Meanwhile, different lengths of the cavity may cause the shift of resonance dips. Also, we study the field enhancement at different vertical locations of the slit. In addition, dielectric materials filling in the annular gaps will result in a shift of the resonance wavelengths, which make the annular cavities good candidates for refractive index sensors. The refractive index sensitivity of annular cavities can also be tuned by the geometry size and the media around the cavity. Annular cavities with novel applications can be implied as surface enhanced Raman spectra substrates, refractive index sensors, nano-lasers, and optical trappers. Project supported by the National Natural Science Foundation of China (Grant No. 61178044), the Natural Science Foundation

Broadband enhancement of single photon emission and polarization dependent coupling in silicon nitride waveguides.

Science.gov (United States)

Bisschop, Suzanne; Guille, Antoine; Van Thourhout, Dries; Hens, Zeger; Brainis, Edouard

2015-06-01

Single-photon (SP) sources are important for a number of optical quantum information processing applications. We study the possibility to integrate triggered solid-state SP emitters directly on a photonic chip. A major challenge consists in efficiently extracting their emission into a single guided mode. Using 3D finite-difference time-domain simulations, we investigate the SP emission from dipole-like nanometer-sized inclusions embedded into different silicon nitride (SiNx) photonic nanowire waveguide designs. We elucidate the effect of the geometry on the emission lifetime and the polarization of the emitted SP. The results show that highly efficient and polarized SP sources can be realized using suspended SiNx slot-waveguides. Combining this with the well-established CMOS-compatible processing technology, fully integrated and complex optical circuits for quantum optics experiments can be developed.

Silicon Photonics towards Disaggregation of Resources in Data Centers

Directory of Open Access Journals (Sweden)

Miltiadis Moralis-Pegios

2018-01-01

Full Text Available In this paper, we demonstrate two subsystems based on Silicon Photonics, towards meeting the network requirements imposed by disaggregation of resources in Data Centers. The first one utilizes a 4 × 4 Silicon photonics switching matrix, employing Mach Zehnder Interferometers (MZIs with Electro-Optical phase shifters, directly controlled by a high speed Field Programmable Gate Array (FPGA board for the successful implementation of a Bloom-Filter (BF-label forwarding scheme. The FPGA is responsible for extracting the BF-label from the incoming optical packets, carrying out the BF-based forwarding function, determining the appropriate switching state and generating the corresponding control signals towards conveying incoming packets to the desired output port of the matrix. The BF-label based packet forwarding scheme allows rapid reconfiguration of the optical switch, while at the same time reduces the memory requirements of the node’s lookup table. Successful operation for 10 Gb/s data packets is reported for a 1 × 4 routing layout. The second subsystem utilizes three integrated spiral waveguides, with record-high 2.6 ns/mm2, delay versus footprint efficiency, along with two Semiconductor Optical Amplifier Mach-Zehnder Interferometer (SOA-MZI wavelength converters, to construct a variable optical buffer and a Time Slot Interchange module. Error-free on-chip variable delay buffering from 6.5 ns up to 17.2 ns and successful timeslot interchanging for 10 Gb/s optical packets are presented.

Experimental Hydraulic Optimization of the Wave Energy Converter Seawave Slot-Cone Generator

DEFF Research Database (Denmark)

Kofoed, Jens Peter

This report presents the results of a experimental hydraulic optimization of the wave energy convert (WEC) Seawave Slot-Cone Generator (SSG). SSG is a WEC utilizing wave overtopping in multiple reservoirs. In the present SSG setup three reservoirs has been used. Model tests have been performed...

Graphene-on-silicon hybrid plasmonic-photonic integrated circuits.

Science.gov (United States)

Xiao, Ting-Hui; Cheng, Zhenzhou; Goda, Keisuke

2017-06-16

Graphene surface plasmons (GSPs) have shown great potential in biochemical sensing, thermal imaging, and optoelectronics. To excite GSPs, several methods based on the near-field optical microscope and graphene nanostructures have been developed in the past few years. However, these methods suffer from their bulky setups and low GSP-excitation efficiency due to the short interaction length between free-space vertical excitation light and the atomic layer of graphene. Here we present a CMOS-compatible design of graphene-on-silicon hybrid plasmonic-photonic integrated circuits that achieve the in-plane excitation of GSP polaritons as well as localized surface plasmon (SP) resonance. By employing a suspended membrane slot waveguide, our design is able to excite GSP polaritons on a chip. Moreover, by utilizing a graphene nanoribbon array, we engineer the transmission spectrum of the waveguide by excitation of localized SP resonance. Our theoretical and computational study paves a new avenue to enable, modulate, and monitor GSPs on a chip, potentially applicable for the development of on-chip electro-optic devices.

PIV and LIF study of slot continuous jet at low Reynolds number

Directory of Open Access Journals (Sweden)

Broučková Zuzana

2016-01-01

Full Text Available This study deals with a continuous jet issuing from a small narrow slot with a width of 0.36 mm. The experimental arrangement is based on the piezoelectric synthetic jet actuator studied previously for easy comparisons. The working fluid is water at room temperature. The experiments were performed using methods of particle image velocimetry (PIV and flow visualization (laser induced fluorescence, LIF. The time-mean volume flux through the exit nozzle was quantified using precise scales. The mean velocity and the Reynolds number were evaluated as Um = 0.12 m/s and Re = 90, respectively. The results of LIF and PIV techniques revealed the three-dimensional character of the flow field, namely the saddle-shape velocity profiles. This behavior is typical for steady jets from a rectangular nozzle. The obtained results were compared with previous measurements of the synthetic jet issuing from the same cavity and the slot nozzle.

The Numerical Sensitivity Study of Cold Leg Top Slot Break for ATLAS

Energy Technology Data Exchange (ETDEWEB)

Sung, Hae Jung; Lee, Sang Ik; Park, Ju hyun; Choi, Tong Soo [KEPCO, Daejeon (Korea, Republic of)

2016-05-15

In this study, cold leg top slot break calculations are performed by RELAP5/MOD3.3 Patch04 for the ATLAS test which is the scaled down experimental facility for the APR1400. The test condition for base case is selected as 0.1016 m (4 in.) based on the break size of the APR1400. In addition, sensitivity studies about break size, break distance from vessel, and pressurizer location are performed until the initiation of simultaneous injection of 2.5 hours. The loop seal reformation occurs early, and the duration of final loop seal reformation is longer as the break is close to vessel. Nonetheless, PCT increased by loop seal reformation is not identified since core uncovery does not occur. In this study, it is confirmed through RELAP5 simulation of the ATLAS test that cold leg top slot break for the APR1400 is not a safety issue in perspective of the loop seal reformation.

Light scattering of rectangular slot antennas: parallel magnetic vector vs perpendicular electric vector

Science.gov (United States)

Lee, Dukhyung; Kim, Dai-Sik

2016-01-01

We study light scattering off rectangular slot nano antennas on a metal film varying incident polarization and incident angle, to examine which field vector of light is more important: electric vector perpendicular to, versus magnetic vector parallel to the long axis of the rectangle. While vector Babinet’s principle would prefer magnetic field along the long axis for optimizing slot antenna function, convention and intuition most often refer to the electric field perpendicular to it. Here, we demonstrate experimentally that in accordance with vector Babinet’s principle, the incident magnetic vector parallel to the long axis is the dominant component, with the perpendicular incident electric field making a small contribution of the factor of 1/|ε|, the reciprocal of the absolute value of the dielectric constant of the metal, owing to the non-perfectness of metals at optical frequencies.

CIRCULARLY POLARIZED SLOT ANTENNA WITH COMPACT SIZE FOR WLAN/WIMAX APPLICATION

Directory of Open Access Journals (Sweden)

Azim Rezaei Motlagh

2014-01-01

Full Text Available In this letter a circle patch that have two slots in ground and patch is presented. The antenna is operated in WLAN/WiMAX at 4.7~6 GHz. The 3dB axial ratio bandwidth is 0.5GHz at 5.3~5.8GHz. Comparison results between measured and simulated of antenna are acceptable.

Ultra-Wideband Printed Slot Radiators with Controllable Frequency Characteristics

Directory of Open Access Journals (Sweden)

S. L. Chernyshev

2015-01-01

Full Text Available We have studied the possibility of creating ultra-wideband (UWB antennas with controlled frequency response of matching based on the printed slot antenna Vivaldi by introducing controlled resonators directly into the structure of the radiator. In the area of irregular slotline there are printed switched resonators with variable capacitance (varactor model, which allow tuning the frequency characteristics for each state of switching cavities, providing bandpass and band-barrage properties of the antenna. The investigation of reconfigurable printed resonators in the system of reconfigurable resonators of a bandpass filter is conducted. The paper considers filter to provide restructuring in the band (3-9 GHz. Electrodynamic simulation of the device was carried out in the time domain using a finite integration method. A bandstop reconfigurable filter is also investigated. The filter located on the substrate opposite the slit is based on tunable L-shaped resonator that has one end connected to the short-circuitor through the board metallization; the other end remains open and is brought into the region of interaction with the slotline. Such filter provides an effective narrow-band suppression and can be easily tuned to the desired frequency channel. The combination of these two types of filters allows you to create a controlled print Vivaldi slot antenna with combined properties. The paper investigates parameters of the scattering and radiation pattern of the antenna in different modes.

Characteristics and infl uence factors of mold fi lling process in permanent mold with a slot gating system

Directory of Open Access Journals (Sweden)

Chen Changjun

2009-11-01

Full Text Available The main problems caused by improper gating are entrained aluminum oxide fi lms and entrapped gas. In this study, the slot gating system is employed to improve mold fi lling behavior and therefore, to improve the quality of aluminum castings produced in permanent molds. An equipment as well as operation procedures for real-time X-ray radiography of molten aluminum fl owing into permanent molds have been developed. Graphite molds transparent to X-rays are utilized which make it possible to observe the fl ow pattern through a number of vertically oriented gating systems. The investigation discovers that there are many infl uencing factors on the mold fi lling process. This paper focuses its research on some of the factors, such as the dimensions of the vertical riser and slot thickness, as well as roughness of the coating layer. The results indicate that molten metal can smoothly fi ll into casting cavity with a proper slot gating system. A bigger vertical riser, proper slot thickness and rougher coating can provide not only a better mold fi lling pattern, but also hot melt into the top of the cavity. A proper temperature gradient is obtainable, higher at the bottom and lower at the top of the casting cavity, which is in favor of feeding during casting solidifi cation.

Implementation of atomic layer etching of silicon: Scaling parameters, feasibility, and profile control

Energy Technology Data Exchange (ETDEWEB)

Ranjan, Alok, E-mail: alok.ranjan@us.tel.com; Wang, Mingmei; Sherpa, Sonam D.; Rastogi, Vinayak [TEL Technology Center, America LLC, 255 Fuller Road, Suite 214, Albany, New York 12203 (United States); Koshiishi, Akira [Tokyo Electron Miyagi, Ltd., 1 Techno-Hills, Taiwa-cho, Kurokawa-gun, Miyagi, 9813629 (Japan); Ventzek, Peter L. G. [Tokyo Electron America, Inc., 2400 Grove Blvd., Austin, Texas 78741 (United States)

2016-05-15

Atomic or layer by layer etching of silicon exploits temporally segregated self-limiting adsorption and material removal steps to mitigate the problems associated with continuous or quasicontinuous (pulsed) plasma processes: selectivity loss, damage, and profile control. Successful implementation of atomic layer etching requires careful choice of the plasma parameters for adsorption and desorption steps. This paper illustrates how process parameters can be arrived at through basic scaling exercises, modeling and simulation, and fundamental experimental tests of their predictions. Using chlorine and argon plasma in a radial line slot antenna plasma source as a platform, the authors illustrate how cycle time, ion energy, and radical to ion ratio can be manipulated to manage the deviation from ideality when cycle times are shortened or purges are incomplete. Cell based Monte Carlo feature scale modeling is used to illustrate profile outcomes. Experimental results of atomic layer etching processes are illustrated on silicon line and space structures such that iso-dense bias and aspect ratio dependent free profiles are produced. Experimental results also illustrate the profile control margin as processes move from atomic layer to multilayer by layer etching. The consequence of not controlling contamination (e.g., oxygen) is shown to result in deposition and roughness generation.

Hybrid rib-slot-rib plasmonic waveguide with deep-subwavelength mode confinement and long propagation length

Directory of Open Access Journals (Sweden)

Kai Zheng

2016-08-01

Full Text Available We propose a hybrid plasmonic waveguide where a combined rib-slot-rib structure is added on the metal substrate within a low-index gap region. The optical properties of the quasi-TM fundamental mode are numerically calculated using the finite element method. Compared to the traditional hybrid plasmonic waveguide, our designed waveguiding structure can support modes with tighter confinement and longer propagation length, by properly adjusting the geometry of the rib-slot-rib structure and the gap height. In details, it can provide the hybrid mode with mode area λ2/12000 and reasonable propagation distance 23.78 μm, simultaneously. Its excellent optical performance can facilitate potential applications in ultra-compact nanophotonic devices and circuits.

Flow Control by Slot Position and Noise Baffle in a Self-Recirculation Casing Treatment on an Axial Fan-Rotor

Directory of Open Access Journals (Sweden)

Xiangjun Li

2017-01-01

Full Text Available To address the situations where the casing treatment needs to be used to stabilize axial compressors through strong recirculation, this paper initiated a CFD study to investigate how the flow could be suitably controlled in the casing treatment to minimize the efficiency penalty and increase the flow range. A counter-swirl self-recirculation casing treatment was first designed on a low speed axial fan rotor as a baseline case. Then three different slot positions and the influence of including the noise baffle were numerically studied. Based on the understanding of their coeffects, the shorter noise baffle was considered and it was found that the highest efficiency was achieved in the case of the upstream slot when the length of baffle was suitably adjusted to balance the incoming flow and recirculation. The largest flow range was achieved by locating the slot at the most downstream position and using a 50% length baffle since it suitably controlled the recirculating flow and relieved the separation at the low-span region. An optimization study showed that the optimum length of the baffle for efficiency was always larger than for the flow range. Both of the two optimum values reduce as the slot moves downstream.

Roll-to-roll slot-die coating of 400 mm wide, flexible, transparent Ag nanowire films for flexible touch screen panels.

Science.gov (United States)

Kim, Dong-Ju; Shin, Hae-In; Ko, Eun-Hye; Kim, Ki-Hyun; Kim, Tae-Woong; Kim, Han-Ki

2016-09-28

We report fabrication of large area Ag nanowire (NW) film coated using a continuous roll-to-roll (RTR) slot die coater as a viable alternative to conventional ITO electrodes for cost-effective and large-area flexible touch screen panels (TSPs). By controlling the flow rate of shear-thinning Ag NW ink in the slot die, we fabricated Ag NW percolating network films with different sheet resistances (30-70 Ohm/square), optical transmittance values (89-90%), and haze (0.5-1%) percentages. Outer/inner bending, twisting, and rolling tests as well as dynamic fatigue tests demonstrated that the mechanical flexibility of the slot-die coated Ag NW films was superior to that of conventional ITO films. Using diamond-shape patterned Ag NW layer electrodes (50 Ohm/square, 90% optical transmittance), we fabricated 12-inch flexible film-film type and rigid glass-film-film type TSPs. Successful operation of flexible TSPs with Ag NW electrodes indicates that slot-die-coated large-area Ag NW films are promising low cost, high performance, and flexible transparent electrodes for cost-effective large-area flexible TSPs and can be substituted for ITO films, which have high sheet resistance and are brittle.

Roll-to-roll slot-die coating of 400 mm wide, flexible, transparent Ag nanowire films for flexible touch screen panels

Science.gov (United States)

Kim, Dong-Ju; Shin, Hae-In; Ko, Eun-Hye; Kim, Ki-Hyun; Kim, Tae-Woong; Kim, Han-Ki

2016-09-01

We report fabrication of large area Ag nanowire (NW) film coated using a continuous roll-to-roll (RTR) slot die coater as a viable alternative to conventional ITO electrodes for cost-effective and large-area flexible touch screen panels (TSPs). By controlling the flow rate of shear-thinning Ag NW ink in the slot die, we fabricated Ag NW percolating network films with different sheet resistances (30-70 Ohm/square), optical transmittance values (89-90%), and haze (0.5-1%) percentages. Outer/inner bending, twisting, and rolling tests as well as dynamic fatigue tests demonstrated that the mechanical flexibility of the slot-die coated Ag NW films was superior to that of conventional ITO films. Using diamond-shape patterned Ag NW layer electrodes (50 Ohm/square, 90% optical transmittance), we fabricated 12-inch flexible film-film type and rigid glass-film-film type TSPs. Successful operation of flexible TSPs with Ag NW electrodes indicates that slot-die-coated large-area Ag NW films are promising low cost, high performance, and flexible transparent electrodes for cost-effective large-area flexible TSPs and can be substituted for ITO films, which have high sheet resistance and are brittle.

Artificial Material Integrated Ultra-wideband Tapered Slot Antenna for Gain Enhancement with Band Notch Characteristics

Directory of Open Access Journals (Sweden)

R. Singha

2018-04-01

Full Text Available The gain of the ultra-wideband tapered slot antenna (TSA is enhanced by using broadband artificial material with band notch characteristics. The proposed artificial material unit cell is designed by fabricating non-resonant three S-shaped parallel metallic line on single side of the dielectric substrate which provides a longer current path compared to the parallel-line structure. The proposed S-shaped structure is printed on the top side of the tapered slot antenna in the extended substrate periodically. The effective refractive index of the artificial material is lower than antenna substrate and phase velocity in the region of artificial material is much higher than the other region. Therefore, the proposed artificial material acts like a beam focusing lens. The band notch at 5.5 GHz is achieved by creating a split ring resonator (SRR slot near the balun. The basic and artificial material loaded TSAs are fabricated and the measurement results show that the gain of the basic antenna has been increased by 1.6 dBi. At the same time, the proposed antenna achieves a VSWR below 2 from 3 to 11 GHz except at 5.5 GHz with a notch band from 5.1 to 5.8 GHz for band rejection of wireless local area network (WLAN application.

Losses Disguised as Wins Affect Game Selection on Multiline Slots.

Science.gov (United States)

Graydon, Candice; Stange, Madison; Dixon, Mike J

2018-05-05

Multiline slots are exciting games that contain features which make them alluring. One such feature is a loss disguised as a win (LDW); wherein, players win less than they wager (e.g., bet 2 dollars, win back 50 cents), but this net loss is disguised by flashing graphics and winning sounds. Research to date concludes that LDWs are both rewarding and reinforcing. Here, we investigated whether LDWs affect players' game selection. Thirty-two undergraduate students with experience playing slot machines played 100 spins on four games-two had positive payback percentages (115%) and two had negative payback percentages (85%) after 100 spins. For each payback percentage condition, there was a game with no LDWs and a game with a moderate number of LDWs. For the 100 spins, players could choose to play whichever game they wished. They then rated their preference for each game following the 100-spins and chose a game to continue playing. The majority of players preferred playing the positive payback percentage game with LDWs and chose to continue playing this game over the three other games. We conclude that in addition to LDWs being reinforcing and rewarding, LDWs do in fact influence game selection. We conclude that responsible gambling initiatives should educate players about LDWs.

Modelling the detachment dependence on strike point location in the small angle slot divertor (SAS) with SOLPS

Science.gov (United States)

Casali, Livia; Covele, Brent; Guo, Houyang

2017-10-01

The new Small Angle Slot (SAS) divertor in DIII-D is characterized by a shallow-angle target enclosed by a slot structure about the strike point (SP). SOLPS modelling results of SAS have demonstrated divertor closure's utility in widening the range of acceptable densities for adequate heat handling. An extensive database of runs has been built to study the detachment dependence on SP location in SAS. Density scans show that lower Te at lower upstream density occur when the SP is at the critical location in the slot. The cooling front spreads across the entire target at higher densities, in agreement with experimental Langmuir probe measurements. A localized increase of the atomic and molecular density takes place near the SP, which reduces the target incident power density and facilitates detachment at lower upstream density. Systematic scans of variables such as power, transport, and viscosity have been carried out to assess the detachment sensitivity. Therein, a positive role of the viscosity is found. This work supported by DOE Contract Number DE-FC02-04ER54698.

Paper-based inkjet-printed tri-band U-slot monopole antenna for wireless applications

KAUST Repository

Abutarboush, Hattan

2012-01-01

Realization of a U-slot tri-band monopole antenna on a low-cost paper substrate using inkjet-printed technology is presented for the first time. The U-shaped slot is optimized to enhance the bandwidth and to achieve tri-band operation of 1.57, 3.2, and 5 GHz with measured impedance bandwidths of 3.21%, 28.1%, and 36%, respectively. The antenna is fabricated through a metallic nanoparticle ink on a standard commercial paper. Thus, the antenna can be used to cover the GPS, WiMAX, HiperLAN/2, and WLAN. The antenna has a compact size of 12 × 37.3 × 0.44 mm3 , leaving enough space for the driving electronics on the paper substrate. The impedance bandwidth, current distributions, radiation patterns, gain, and efficiency of the antenna have been studied through computer simulations and measurements. © 2002-2011 IEEE.

Pulsed electromagnetic field radiation from a narrow slot antenna with a dielectric layer

NARCIS (Netherlands)

Štumpf, M.; De Hoop, A.T.; Lager, I.E.

2010-01-01

Analytic time domain expressions are derived for the pulsed electromagnetic field radiated by a narrow slot antenna with a dielectric layer in a two?dimensional model configuration. In any finite time window of observation, exact pulse shapes for the propagated, reflected, and refracted wave

Millimeter-Wave Wireless Power Transfer Technology for Space Applications

Science.gov (United States)

Chattopadhyay, Goutam; Manohara, Harish; Mojarradi, Mohammad M.; Vo, Tuan A.; Mojarradi, Hadi; Bae, Sam Y.; Marzwell, Neville

2008-01-01

In this paper we present a new compact, scalable, and low cost technology for efficient receiving of power using RF waves at 94 GHz. This technology employs a highly innovative array of slot antennas that is integrated on substrate composed of gold (Au), silicon (Si), and silicon dioxide (SiO2) layers. The length of the slots and spacing between them are optimized for a highly efficient beam through a 3-D electromagnetic simulation process. Antenna simulation results shows a good beam profile with very low side lobe levels and better than 93% antenna efficiency.

Silicon Nitride Background in Nanophotonic Waveguide Enhanced Raman Spectroscopy

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Ashim Dhakal

2017-02-01

Full Text Available Recent studies have shown that evanescent Raman spectroscopy using a silicon nitride (SiN nanophotonic waveguide platform has higher signal enhancement when compared to free-space systems. However, signal-to-noise ratio from the waveguide at a low analyte concentration is constrained by the shot-noise from the background light originating from the waveguide itself. Hence, understanding the origin and properties of this waveguide background luminescence (WGBL is essential to developing mitigation strategies. Here, we identify the dominating component of the WGBL spectrum composed of a broad Raman scattering due to momentum selection-rule breaking in amorphous materials, and several peaks specific to molecules embedded in the core. We determine the maximum of the Raman scattering efficiency of the WGBL at room temperature for 785 nm excitation to be 4.5 ± 1 × 10−9 cm−1·sr−1, at a Stokes shift of 200 cm−1. This efficiency decreases monotonically for higher Stokes shifts. Additionally, we also demonstrate the use of slotted waveguides and quasi-transverse magnetic polarization as some mitigation strategies.

A PML-FDTD ALGORITHM FOR SIMULATING PLASMA-COVERED CAVITY-BACKED SLOT ANTENNAS. (R825225)

Science.gov (United States)

A three-dimensional frequency-dependent finite-difference time-domain (FDTD) algorithm with perfectly matched layer (PML) absorbing boundary condition (ABC) and recursive convolution approaches is developed to model plasma-covered open-ended waveguide or cavity-backed slot antenn...

Wave Loadings on Seawave Slot-Cone Generator (SSG) at Kvitsøy Island

DEFF Research Database (Denmark)

Vicinanza, Diego; Frigaard, Peter; Kofoed, Jens Peter

This report presents results from a new research study performed to derive information on wave loadings acting on Wave Energy Convert (WEC) Seawave Slot-Cone Generator (SSG) exposed to extreme wave conditions. The SSG concept is based on the principle of overtopping and stores the wave energy...

A U-Shaped Slot UWB Antenna with Flexible and Wide Tunable Dual Notch Band

Directory of Open Access Journals (Sweden)

Zhang Zhongmin

2016-01-01

Full Text Available A coplanar waveguide (CPW fed ultra-wideband (UWB antenna with flexible and wide tunable dual bandnotched characteristics is proposed in this paper. The dual band-notched function is achieved by using an U-shaped slot inserted into the ellipse radiation patch and by using an elliptic parasitic slit placed near the ground plane. The wide tunable band-notched characteristic is implemented by adjusting the length of U-shaped slot and by adjusting the length of ellipse parasitic slit. The design aims to achieve wide reconfigurable band-notched features on the UWB antenna. The simulated results indicate that the proposed antenna has a wide bandwidth (VSWR under 2 from 2.9GHz to 12.6GHz with fractional bandwidth of 125%, and has a wide tunable notch band center frequency from 4.5GHz to 12.4GHz.

Quadrature Slotted Surface Coil Pair for Magnetic Resonance Imaging at 4 Tesla: Phantom Study

Directory of Open Access Journals (Sweden)

Solis S.E.

2012-01-01

Full Text Available A coil array was composed of two slotted surface coils forming a structure with two plates at 900, each one having 6 circular slots and is introduced in this paper. Numerical simulations of the magnetic field of this coil array were performed at 170 MHz using the finite element method to study its behaviour. This coil array was developed for brain magnetic resonance imaging to be operated at the resonant frequency of 170 MHz in the transceiver mode and quadrature driven. Numerical simulations demonstrated that electromagnetic interaction between the coil elements is negligible, and that the magnetic field showed a good uniformity. Phantom images were acquired with our coil array and standard pulse sequences on a research-dedicated 4 Tesla scanner. In vitro images showed the feasibility of this coil array for standard pulses and high field magnetic resonance imaging.

A Novel Structure and Design Optimization of Compact Spline-Parameterized UWB Slot Antenna

Directory of Open Access Journals (Sweden)

Koziel Slawomir

2016-12-01

Full Text Available In this paper, a novel structure of a compact UWB slot antenna and its design optimization procedure has been presented. In order to achieve a sufficient number of degrees of freedom necessary to obtain a considerable size reduction rate, the slot is parameterized using spline curves. All antenna dimensions are simultaneously adjusted using numerical optimization procedures. The fundamental bottleneck here is a high cost of the electromagnetic (EM simulation model of the structure that includes (for reliability an SMA connector. Another problem is a large number of geometry parameters (nineteen. For the sake of computational efficiency, the optimization process is therefore performed using variable-fidelity EM simulations and surrogate-assisted algorithms. The optimization process is oriented towards explicit reduction of the antenna size and leads to a compact footprint of 199 mm2 as well as acceptable matching within the entire UWB band. The simulation results are validated using physical measurements of the fabricated antenna prototype.

The Effects of In-Office Reconditioning on the Slot Dimensions and Static Frictional Resistance of Stainless Steel Brackets.

Science.gov (United States)

Iluru, Rohini; Nellore, Chaitanya; Karnati, Praveen Kumar Reddy; Thalapaneni, Ashok Kumar; Myla, Vijay Bhaskar; Ramyasree, Konda; Prasad, Mandava

2016-01-01

Orthodontists are commonly faced with the decision of what to do with loose brackets, and with inaccurately located brackets that need repositioning during treatment. One solution is to recycle the brackets. The potential effects of reconditioning a bracket are dependent upon many factors which may result in physical changes like alteration in slot tolerance, which may influence sliding mechanics by affecting frictional resistance. To study and compare the dimensional changes in the bracket slot width and depth in reconditioned brackets from unused brackets under scanning electronic microscope and to study and compare any consequent effects on the static frictional resistance of stainless steel brackets after reconditioning and in unused brackets. Dentarum manufactured 90 stainless steel central incisors edgewise brackets of size 0.22 X 0.030″ inch and 0° tip and 0°angulation were taken. 60 samples for measuring frictional resistance and 30 samples for measuring slot dimensions. Ortho organizers manufactured stainless steel arch wires 0.019 X 0.025″ straight lengths 60 in number were considered for measuring static frictional resistance. The mean slot width and depth of new brackets were 0.0251″ and 0.0471″, which exceeded the manufacturers reported nominal size of 0.022″ X 0.030″, by 0.003″ and 0.017″. The reconditioned brackets demonstrated a further increase in mean slot width and depth to 0.028″ and 0.0518″ that is by 0.0035″ and 0.0047″ which is statistically significant (p=0.001, 0.002). The mean static frictional forces of the reconditioned brackets was nearly similar to that of new brackets that is 0.3167N for reconditioned brackets and 0.2613 N for new brackets. Although the reconditioning process results in physical changes to bracket structure this does not appear to result in significant effect on ex-vivo static frictional resistance.

Pulsar Polar Cap and Slot Gap Models: Confronting Fermi Data

Science.gov (United States)

Harding, Alice K.

2012-01-01

Rotation-powered pulsars are excellent laboratories for studying particle acceleration as well as fundamental physics of strong gravity, strong magnetic fields and relativity. I will review acceleration and gamma-ray emission from the pulsar polar cap and slot gap. Predictions of these models can be tested with the data set on pulsars collected by the Large Area Telescope on the Fermi Gamma-Ray Telescope over the last four years, using both detailed light curve fitting and population synthesis.

Photoluminescence and electrical properties of silicon oxide and silicon nitride superlattices containing silicon nanocrystals

International Nuclear Information System (INIS)

Shuleiko, D V; Ilin, A S

2016-01-01

Photoluminescence and electrical properties of superlattices with thin (1 to 5 nm) alternating silicon-rich silicon oxide or silicon-rich silicon nitride, and silicon oxide or silicon nitride layers containing silicon nanocrystals prepared by plasma-enhanced chemical vapor deposition with subsequent annealing were investigated. The entirely silicon oxide based superlattices demonstrated photoluminescence peak shift due to quantum confinement effect. Electrical measurements showed the hysteresis effect in the vicinity of zero voltage due to structural features of the superlattices from SiOa 93 /Si 3 N 4 and SiN 0 . 8 /Si 3 N 4 layers. The entirely silicon nitride based samples demonstrated resistive switching effect, comprising an abrupt conductivity change at about 5 to 6 V with current-voltage characteristic hysteresis. The samples also demonstrated efficient photoluminescence with maximum at ∼1.4 eV, due to exiton recombination in silicon nanocrystals. (paper)

Method and allocation device for allocating pending requests for data packet transmission at a number of inputs to a number of outputs of a packet switching device in successive time slots

Science.gov (United States)

Abel, Francois [Rueschlikon, CH; Iliadis, Ilias [Rueschlikon, CH; Minkenberg, Cyriel J. A. [Adliswil, CH

2009-02-03

A method for allocating pending requests for data packet transmission at a number of inputs to a number of outputs of a switching system in successive time slots, including a matching method including the steps of providing a first request information in a first time slot indicating data packets at the inputs requesting transmission to the outputs of the switching system, performing a first step in the first time slot depending on the first request information to obtain a first matching information, providing a last request information in a last time slot successive to the first time slot, performing a last step in the last time slot depending on the last request information and depending on the first matching information to obtain a final matching information, and assigning the pending data packets at the number of inputs to the number of outputs based on the final matching information.

Slot-type kicker for the AA stochastic cooling

CERN Multimedia

Photographic Service

1979-01-01

A "slotted transmission line" structure was used for both pickups and the kicker of one of the stochastic cooling systems of the Antiproton Accumulator (AA). They served for the cooling of the high-density stack, in momentum and in both transverse planes. In the beginning in a single band, 1-2 GHz, later in 3 bands, 1-2, 2-4 and 4-8 GHz. The kicker of the first generation, shown here, was located where the dispersion was zero and the beam size small, and thus had a quadratic cross-section. The pickups were rectangular and wider in the horizontal plane. See also 7906193

PIV and LIF study of slot continuous jet at low Reynolds number

Czech Academy of Sciences Publication Activity Database

Broučková, Zuzana; Hsu, S.S.; Wang, A. B.; Trávníček, Zdeněk

2016-01-01

Roč. 114, March (2016), č. článku 02007. ISSN 2101-6275. [International Conference on Experimental Fluid Mechanics /10./. Praha, 17.11.2015-20.11.2015] R&D Projects: GA ČR GA14-08888S Institutional support: RVO:61388998 Keywords : continuous jet * slot jet * particle image velocimetry Subject RIV: JU - Aeronautics, Aerodynamics, Aircrafts

Simultaneous multilayer formation of the polymer solar cell stack using roll-to-roll double slot-die coating from water

DEFF Research Database (Denmark)

Larsen-Olsen, Thue Trofod; Andreasen, Birgitta; Andersen, Thomas Rieks

2012-01-01

zinc oxide that was processed by single slot-die coating from water. The active layer comprised poly-3-hexylthiophene:Phenyl-C61-butyric acid methyl ester (P3HT:PCBM) as a dispersion of nanoparticles with a radius of 46 nm in water characterized using small-angle X-ray scattering (SAXS), transmission...... electron microscopy (TEM), and atomic force microscopy (AFM). The HTL was a dispersion of poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) in water. The films were analyzed using time-of-flight secondary ion mass spectrometry (TOF-SIMS) as chemical probe and X-ray reflectometry......), fill factor (FF), and power conversion efficiency (PCE) of 0.24 V, 0.5 mA cm−2, 25%, and 0.03%, respectively, for the best double slot-die coated cell. A single slot-die coated cell using the same aqueous inks and device architecture yielded a Voc, Jsc, FF, and PCE of 0.45 V, 1.95 mA cm−2, 33.1%, and 0...

Biologically Inspired Intercellular Slot Synchronization

Directory of Open Access Journals (Sweden)

Alexander Tyrrell

2009-01-01

Full Text Available The present article develops a decentralized interbase station slot synchronization algorithm suitable for cellular mobile communication systems. The proposed cellular firefly synchronization (CelFSync algorithm is derived from the theory of pulse-coupled oscillators, common to describe synchronization phenomena in biological systems, such as the spontaneous synchronization of fireflies. In order to maintain synchronization among base stations (BSs, even when there is no direct link between adjacent BSs, some selected user terminals (UTs participate in the network synchronization process. Synchronization emerges by exchanging two distinct synchronization words, one transmitted by BSs and the other by active UTs, without any a priori assumption on the initial timing misalignments of BSs and UTs. In large-scale networks with inter-BS site distances up to a few kilometers, propagation delays severely affect the attainable timing accuracy of CelFSync. We show that by an appropriate combination of CelFSync with the timing advance procedure, which aligns uplink transmission of UTs to arrive simultaneously at the BS, a timing accuracy within a fraction of the inter-BS propagation delay is retained.

A micro-force sensor with slotted-quad-beam structure for measuring the friction in MEMS bearings.

Science.gov (United States)

Liu, Huan; Yang, Shuming; Zhao, Yulong; Jiang, Zhuangde; Liu, Yan; Tian, Bian

2013-09-30

Presented here is a slotted-quad-beam structure sensor for the measurement of friction in micro bearings. Stress concentration slots are incorporated into a conventional quad-beam structure to improve the sensitivity of force measurements. The performance comparison between the quad-beam structure sensor and the slotted-quad-beam structure sensor are performed by theoretical modeling and finite element (FE) analysis. A hollow stainless steel probe is attached to the mesa of the sensor chip by a tailor-made organic glass fixture. Concerning the overload protection of the fragile beams, a glass wafer is bonded onto the bottom of sensor chip to limit the displacement of the mesa. The calibration of the packaged device is experimentally performed by a tri-dimensional positioning stage, a precision piezoelectric ceramic and an electronic analytical balance, which indicates its favorable sensitivity and overload protection. To verify the potential of the proposed sensor being applied in micro friction measurement, a measurement platform is established. The output of the sensor reflects the friction of bearing resulting from dry friction and solid lubrication. The results accord with the theoretical modeling and demonstrate that the sensor has the potential application in measuring the micro friction force under stable stage in MEMS machines.

A Micro-Force Sensor with Slotted-Quad-Beam Structure for Measuring the Friction in MEMS Bearings

Directory of Open Access Journals (Sweden)

Yan Liu

2013-09-01

Full Text Available Presented here is a slotted-quad-beam structure sensor for the measurement of friction in micro bearings. Stress concentration slots are incorporated into a conventional quad-beam structure to improve the sensitivity of force measurements. The performance comparison between the quad-beam structure sensor and the slotted-quad-beam structure sensor are performed by theoretical modeling and finite element (FE analysis. A hollow stainless steel probe is attached to the mesa of the sensor chip by a tailor-made organic glass fixture. Concerning the overload protection of the fragile beams, a glass wafer is bonded onto the bottom of sensor chip to limit the displacement of the mesa. The calibration of the packaged device is experimentally performed by a tri-dimensional positioning stage, a precision piezoelectric ceramic and an electronic analytical balance, which indicates its favorable sensitivity and overload protection. To verify the potential of the proposed sensor being applied in micro friction measurement, a measurement platform is established. The output of the sensor reflects the friction of bearing resulting from dry friction and solid lubrication. The results accord with the theoretical modeling and demonstrate that the sensor has the potential application in measuring the micro friction force under stable stage in MEMS machines.

Slot Machines: Pursuing Responsible Gaming Practices for Virtual Reels and Near Misses

Science.gov (United States)

Harrigan, Kevin A.

2009-01-01

Since 1983, slot machines in North America have used a computer and virtual reels to determine the odds. Since at least 1988, a technique called clustering has been used to create a high number of near misses, failures that are close to wins. The result is that what the player sees does not represent the underlying probabilities and randomness,…

PVD Silicon Carbide as a Thin Film Packaging Technology for Antennas on LCP Substrates for Harsh Environments

Science.gov (United States)

Scardelletti, Maximilian C.; Stanton, John W.; Ponchak, George E.; Jordan, Jennifer L.; Zorman, Christian A.

2010-01-01

This paper describes an effort to develop a thin film packaging technology for microfabricated planar antennas on polymeric substrates based on silicon carbide (SiC) films deposited by physical vapor deposition (PVD). The antennas are coplanar waveguide fed dual frequency folded slot antennas fabricated on liquid crystal polymer (LCP) substrates. The PVD SiC thin films were deposited directly onto the antennas by RF sputtering at room temperature at a chamber pressure of 30 mTorr and a power level of 300 W. The SiC film thickness is 450 nm. The return loss and radiation patterns were measured before and after the SiC-coated antennas were submerged into perchloric acid for 1 hour. No degradation in RF performance or physical integrity of the antenna was observed.

A Comparison of the Accuracy of 0.022 Slots at Face, Base and Mesial and Distal Surface of Brackets marketed by Different Manufacturers

Directory of Open Access Journals (Sweden)

Karan Tangri

2012-01-01

Conclusion: The results of this study indicate that orthodontic bracket slots were different than stated by the manufacturers. All the brackets were larger at the face than at the base. Clinicians should be aware that there may be a three-dimensional loss of tooth positioning as a result of the inadvertent use of orthodontic brackets with inaccurate slots.

Stability of a slotted ALOHA system with capture effect

Science.gov (United States)

Onozato, Yoshikuni; Liu, Jin; Noguchi, Shoichi

1989-02-01

The stability of a slotted ALOHA system with capture effect is investigated under a general communication environment where terminals are divided into two groups (low-power and high-power) and the capture effect is modeled by capture probabilities. An approximate analysis is developed using catastrophe theory, in which the effects of system and user parameters on the stability are characterized by the cusp catastrophe. Particular attention is given to the low-power group, since it must bear the strain under the capture effect. The stability conditions of the two groups are given explicitly by bifurcation sets.

Quad-Band U-Slot Antenna for Mobile Applications

Directory of Open Access Journals (Sweden)

R. L. Ruiz

2006-06-01

Full Text Available In this paper, two different planar quad-band antennas are designed, modeled, fabricated and measured. Subsequently, the antennas are redesigned using an electromagnetic band gap substrate (EBG. Those new planar antennas operate in four frequency bands: 900 MHz, 1 800 MHz (both GSM, 1 900 MHz (USA and 2 400 to 2 500 MHz (Bluetooth The antenna has four narrow U-shaped slots etched to the patch. Using software, CST Microwave Studio [1], Zeland IE3D [2], and FEMLAB [3], simulations have been carried out to investigate the antenna's performance and characteristics. The antennas designed have been also built and measured to compare the real results with those obtained from the simulations.

Investigation of a Novel Turbulence Model and Using Leading-Edge Slots for Improving the Aerodynamic Performance of Airfoils and Wind Turbines

Science.gov (United States)

Beyhaghi, Saman

as compared to the baseline DES. In the second part of this study, the focus is on improving the aerodynamic performance of airfoils and wind turbines in terms of lift and drag coefficients and power generation. One special type of add-on feature for wind turbines and airfoils, i.e., leading-edge slots are investigated through numerical simulation and laboratory experiments. Although similar slots are designed and employed for aircrafts, a special slot with a reversed flow direction is drilled in the leading edge of a sample wind turbine airfoil to study its influence on the aerodynamic performance. The objective is to vary the five main geometrical parameters of slot and characterize the performance improvement of the new design under different operating conditions. A number of Design of Experiment and optimization studies are conducted to determine the most suitable slot configuration to maximize the lift or lift-over-drag ratio. Results indicate that proper sizing and placement of slot can improve the lift coefficient, while it has negligible negative impact on the drag. Some recommendations for future investigation on slot are proposed at the end. The performance of a horizontal axis wind turbine blade equipped with leading-edge slot is also studied, and it is concluded that slotted blades can generate about 10% more power than solid blades, for the two operating conditions investigated. The good agreement between the CFD predictions and experimental data confirms the validity of the model and results.

Eddy current loss analysis of open-slot fault-tolerant permanent-magnet machines based on conformal mapping method

Science.gov (United States)

Ji, Jinghua; Luo, Jianhua; Lei, Qian; Bian, Fangfang

2017-05-01

This paper proposed an analytical method, based on conformal mapping (CM) method, for the accurate evaluation of magnetic field and eddy current (EC) loss in fault-tolerant permanent-magnet (FTPM) machines. The aim of modulation function, applied in CM method, is to change the open-slot structure into fully closed-slot structure, whose air-gap flux density is easy to calculate analytically. Therefore, with the help of Matlab Schwarz-Christoffel (SC) Toolbox, both the magnetic flux density and EC density of FTPM machine are obtained accurately. Finally, time-stepped transient finite-element method (FEM) is used to verify the theoretical analysis, showing that the proposed method is able to predict the magnetic flux density and EC loss precisely.

Effect of magnet/slot combination on triple-frequency magnetic force and vibration of permanent magnet motors

Science.gov (United States)

Huo, Mina; Wang, Shiyu; Xiu, Jie; Cao, Shuqian

2013-10-01

The relationship between magnet/slot combination and magnetic forces including unbalanced magnetic force (UMF) and cogging torque (CT) of permanent magnet (PM) motors is investigated by using superposition principle and mechanical and magnetic symmetries. The results show that magnetic force can be produced by all magnets passing a single slot, by all slots passing a single magnet, or by eccentricity, which respectively correspond to three frequency components. The results further show that net force/torque can be classified into three typical cases: UMF is suppressed and CT is excited, UMF excited and CT suppressed, and UMF and CT both suppressed, and consequently possible vibrations include three unique groups: rotational modes, translational modes, and balanced modes. The conclusion that combinations with the greatest common divisor (GCD) greater than unity can avoid UMF is mathematically verified, and at the same time lower CT harmonics are preliminarily addressed by the typical excitations. The above findings can create simple guidelines for the suppression of certain UMF and/or CT by using suitable combinations, which in turn can present approach to yield a more desirable response in high performance applications. The superposition effect and predicted relationship are verified by the transient magnetic Finite Element method. Since this work is motivated by symmetries, comparisons are made in order to give further insight into the inner force and vibration behaviors of general rotary power-transmission systems.

A positive correlation between energetic electron butterfly distributions and magnetosonic waves in the radiation belt slot region

International Nuclear Information System (INIS)

Yang, Chang; Su, Z.; Xiao, F.; Zheng, H.

2017-01-01

Energetic (hundreds of keV) electrons in the radiation belt slot region have been found to exhibit the butterfly pitch angle distributions. Resonant interactions with magnetosonic and whistler-mode waves are two potential mechanisms for the formation of these peculiar distributions. Here we perform a statistical study of energetic electron pitch angle distribution characteristics measured by Van Allen Probes in the slot region during a three-year period from May 2013 to May 2016. Our results show that electron butterfly distributions are closely related to magnetosonic waves rather than to whistlermode waves. Both electron butterfly distributions and magnetosonic waves occur more frequently at the geomagnetically active times than at the quiet times. In a statistical sense, more distinct butterfly distributions usually correspond to magnetosonic waves with larger amplitudes and vice versa. The averaged magnetosonic wave amplitude is less than 5 pT in the case of normal and flat-top distributions with a butterfly index BI = 1 but reaches ~ 35–95 pT in the case of distinct butterfly distributions with BI > 1:3. For magnetosonic waves with amplitudes > 50 pT, the occurrence rate of butterfly distribution is above 80%. Our study suggests that energetic electron butterfly distributions in the slot region are primarily caused by magnetosonic waves.

Dynamic thermo-chemo-mechanical strain of Zircaloy-4 slotted rings for evaluating strategies that mitigate stress corrosion cracking

Energy Technology Data Exchange (ETDEWEB)

Ferrier, G.A.; Metzler, J.; Farahani, M.; Chan, P.K.; Corcoran, E.C. [Royal Military College of Canada, Kingston, ON (Canada)

2014-07-01

Stress corrosion cracking (SCC) in Zircaloy-4 fuel sheaths has been investigated by static loading of slotted ring samples under hot and corrosive conditions. However, in nuclear reactors, power ramps can have short (e.g., 10-20 minutes) and recurring time frames due to dynamic processes such as on-power refuelling, adjuster rod manoeuvres, and load following. Therefore, to enable out-reactor dynamic testing, an apparatus was designed to dynamically strain slotted ring samples under SCC conditions. This apparatus can additionally be used to test fatigue properties. Unique capabilities of this apparatus and preliminary results obtained from static and dynamic tests are presented. (author)

Silicone metalization

Energy Technology Data Exchange (ETDEWEB)

Maghribi, Mariam N. (Livermore, CA); Krulevitch, Peter (Pleasanton, CA); Hamilton, Julie (Tracy, CA)

2008-12-09

A system for providing metal features on silicone comprising providing a silicone layer on a matrix and providing a metal layer on the silicone layer. An electronic apparatus can be produced by the system. The electronic apparatus comprises a silicone body and metal features on the silicone body that provide an electronic device.

Formation of porous silicon oxide from substrate-bound silicon rich silicon oxide layers by continuous-wave laser irradiation

Science.gov (United States)

Wang, Nan; Fricke-Begemann, Th.; Peretzki, P.; Ihlemann, J.; Seibt, M.

2018-03-01

Silicon nanocrystals embedded in silicon oxide that show room temperature photoluminescence (PL) have great potential in silicon light emission applications. Nanocrystalline silicon particle formation by laser irradiation has the unique advantage of spatially controlled heating, which is compatible with modern silicon micro-fabrication technology. In this paper, we employ continuous wave laser irradiation to decompose substrate-bound silicon-rich silicon oxide films into crystalline silicon particles and silicon dioxide. The resulting microstructure is studied using transmission electron microscopy techniques with considerable emphasis on the formation and properties of laser damaged regions which typically quench room temperature PL from the nanoparticles. It is shown that such regions consist of an amorphous matrix with a composition similar to silicon dioxide which contains some nanometric silicon particles in addition to pores. A mechanism referred to as "selective silicon ablation" is proposed which consistently explains the experimental observations. Implications for the damage-free laser decomposition of silicon-rich silicon oxides and also for controlled production of porous silicon dioxide films are discussed.

Experimental and numerical study of the accuracy of flame-speed measurements for methane/air combustion in a slot burner

Energy Technology Data Exchange (ETDEWEB)

Selle, L.; Ferret, B. [Universite de Toulouse, INPT, UPS, IMFT, Institut de Mecanique des Fluides de Toulouse (France); CNRS, IMFT, Toulouse (France); Poinsot, T. [Universite de Toulouse, INPT, UPS, IMFT, Institut de Mecanique des Fluides de Toulouse (France); CNRS, IMFT, Toulouse (France); CERFACS, Toulouse (France)

2011-01-15

Measuring the velocities of premixed laminar flames with precision remains a controversial issue in the combustion community. This paper studies the accuracy of such measurements in two-dimensional slot burners and shows that while methane/air flame speeds can be measured with reasonable accuracy, the method may lack precision for other mixtures such as hydrogen/air. Curvature at the flame tip, strain on the flame sides and local quenching at the flame base can modify local flame speeds and require corrections which are studied using two-dimensional DNS. Numerical simulations also provide stretch, displacement and consumption flame speeds along the flame front. For methane/air flames, DNS show that the local stretch remains small so that the local consumption speed is very close to the unstretched premixed flame speed. The only correction needed to correctly predict flame speeds in this case is due to the finite aspect ratio of the slot used to inject the premixed gases which induces a flow acceleration in the measurement region (this correction can be evaluated from velocity measurement in the slot section or from an analytical solution). The method is applied to methane/air flames with and without water addition and results are compared to experimental data found in the literature. The paper then discusses the limitations of the slot-burner method to measure flame speeds for other mixtures and shows that it is not well adapted to mixtures with a Lewis number far from unity, such as hydrogen/air flames. (author)

Oxygen defect processes in silicon and silicon germanium

KAUST Repository

Chroneos, A.

2015-06-18

Silicon and silicon germanium are the archetypical elemental and alloy semiconductor materials for nanoelectronic, sensor, and photovoltaic applications. The investigation of radiation induced defects involving oxygen, carbon, and intrinsic defects is important for the improvement of devices as these defects can have a deleterious impact on the properties of silicon and silicon germanium. In the present review, we mainly focus on oxygen-related defects and the impact of isovalent doping on their properties in silicon and silicon germanium. The efficacy of the isovalent doping strategies to constrain the oxygen-related defects is discussed in view of recent infrared spectroscopy and density functional theory studies.

Oxygen defect processes in silicon and silicon germanium

KAUST Repository

Chroneos, A.; Sgourou, E. N.; Londos, C. A.; Schwingenschlö gl, Udo

2015-01-01

Silicon and silicon germanium are the archetypical elemental and alloy semiconductor materials for nanoelectronic, sensor, and photovoltaic applications. The investigation of radiation induced defects involving oxygen, carbon, and intrinsic defects is important for the improvement of devices as these defects can have a deleterious impact on the properties of silicon and silicon germanium. In the present review, we mainly focus on oxygen-related defects and the impact of isovalent doping on their properties in silicon and silicon germanium. The efficacy of the isovalent doping strategies to constrain the oxygen-related defects is discussed in view of recent infrared spectroscopy and density functional theory studies.

Recombinant antigen-based immuno-slot blot method for serodiagnosis of syphilis

Directory of Open Access Journals (Sweden)

N.S. Sato

2004-07-01

Full Text Available Three recombinant antigens of Treponema pallidum Nichols strain were fused with GST, cloned and expressed in Escherichia coli, resulting in high levels of GST-rTp47 and GST-rTp17 expression, and supplementation with arginine tRNA for the AGR codon was needed to obtain GST-rTp15 overexpression. Purified fusion protein yields were 1.9, 1.7 and 5.3 mg/l of cell culture for GST-rTp47, GST-rTp17 and GST-rTp15, respectively. The identities of the antigens obtained were confirmed by automated DNA sequencing using ABI Prism 310 and peptide mapping by Finningan LC/MS. These recombinant antigens were evaluated by immuno-slot blot techniques applied to 137 serum samples from patients with a clinical and laboratory diagnosis of syphilis (61 samples, from healthy blood donors (50 samples, individuals with sexually transmitted disease other than syphilis (3 samples, and from individuals with other spirochetal diseases such as Lyme disease (20 samples and leptospirosis (3 samples. The assay had sensitivity of 95.1% (95% CI, 86.1 to 98.7% and a specificity of 94.7% (95% CI, 87.0 to 98.7%; a stronger reactivity was observed with fraction rTp17. The immunoreactivity results showed that fusion recombinant antigens based-immuno-slot blot techniques are suitable for use in diagnostic assays for syphilis.

Desain dan Implementasi Variasi Dimensi Slot Pada Mikrostrip Double F Menggunakan Metode Finite Difference Time Domain (FDTD

Directory of Open Access Journals (Sweden)

Nurista Wahyu Kirana

2016-06-01

Full Text Available Pada penelitian ini dirancang antena mikrostrip dengan slot double F, di mana antena ini dapat digunakan untuk perangkat wireless yang bekerja pada frekuensi multiband. Antena mikrostrip double F dirancang dengan simulasi, dipabrikasi dan diukur secara riil. Finite Difference Time Domain (FDTD digunakan untuk menganalisis karakteristik distribusi arus yang tersebar pada mikrostrip. Nilai parameter terbaik dari hasil simulasi untuk return loss adalah -31,09 dB pada frekuensi 2,4 GHz dan VSWR sebesar 1,057 sedangkan hasil pengukurannya sebesar -32,82 dB pada frekuensi 2,4 GHz dan VSWR sebesar 1,045. Penggunaan slot pada patch antena dan pencatuan proximity yang digunakan meningkatkan bandwidth antena sebesar 48,7% dan gain yang dihasilkan sebesar 5,97 dBi.

Comparison of CsI(Tl) and CsI(Na) partially slotted crystals for high-resolution SPECT imaging

International Nuclear Information System (INIS)

Giokaris, N.; Loudos, G.; Maintas, D.; Karabarbounis, A.; Lembesi, M.; Spanoudaki, V.; Stiliaris, E.; Boukis, S.; Sakellios, N.; Karakatsanis, N.; Gektin, A.; Boyarintsev, A.; Pedash, V.; Gayshan, V.

2006-01-01

Dedicated systems based on Position Sensitive Photomultiplier Tubes (PSPMTs) coupled to scintillators, have been used over the past years for the construction of compact systems, suitable for applications such as small animal imaging and small organs imaging. Most of the proposed systems are based on fully pixelized scintillators. Previous studies have shown that partially slotted scintillators offer a good compromise between cost, energy resolution and spatial resolution. In this work, the performance of two sets of CsI(Tl) and CsI(Na) partially slotted crystals is compared. Initial results show that CsI(Tl) scintillators are more suitable for gamma-ray detection, since their performance in terms of sensitivity, spatial and energy resolution is superior than that of CsI(Na)

Time evolution of propagating nonpremixed flames in a counterflow, annular slot burner under AC electric fields

KAUST Repository

Tran, Vu Manh; Cha, Min

2016-01-01

alternating current electric fields to a gap between the upper and lower parts of a counterflow, annular slot burner and present the characteristics of the propagating nonpremixed edge-flames produced. Contrary to many other previous studies, flame

The effects of alcohol expectancy and intake on slot machine gambling behavior.

Science.gov (United States)

Sagoe, Dominic; Mentzoni, Rune Aune; Leino, Tony; Molde, Helge; Haga, Sondre; Gjernes, Mikjel Fredericson; Hanss, Daniel; Pallesen, Ståle

2017-06-01

Background and aims Although alcohol intake and gambling often co-occur in related venues, there is conflicting evidence regarding the effects of alcohol expectancy and intake on gambling behavior. We therefore conducted an experimental investigation of the effects of alcohol expectancy and intake on slot machine gambling behavior. Methods Participants were 184 (females = 94) individuals [age range: 18-40 (mean = 21.9) years] randomized to four independent conditions differing in information/expectancy about beverage (told they received either alcohol or placebo) and beverage intake [actually ingesting low (target blood alcohol concentration [BAC]  0.40 mg/L; ≈0.80 mg/L) amounts of alcohol]. All participants completed self-report questionnaires assessing demographic variables, subjective intoxication, alcohol effects (stimulant and sedative), and gambling factors (behavior and problems, evaluation, and beliefs). Participants also gambled on a simulated slot machine. Results A significant main effect of beverage intake on subjective intoxication and alcohol effects was detected as expected. No significant main or interaction effects were detected for number of gambling sessions, bet size and variation, remaining credits at termination, reaction time, and game evaluation. Conclusion Alcohol expectancy and intake do not affect gambling persistence, dissipation of funds, reaction time, or gambling enjoyment.

A slotted access control protocol for metropolitan WDM ring networks

Science.gov (United States)

Baziana, P. A.; Pountourakis, I. E.

2009-03-01

In this study we focus on the serious scalability problems that many access protocols for WDM ring networks introduce due to the use of a dedicated wavelength per access node for either transmission or reception. We propose an efficient slotted MAC protocol suitable for WDM ring metropolitan area networks. The proposed network architecture employs a separate wavelength for control information exchange prior to the data packet transmission. Each access node is equipped with a pair of tunable transceivers for data communication and a pair of fixed tuned transceivers for control information exchange. Also, each access node includes a set of fixed delay lines for synchronization reasons; to keep the data packets, while the control information is processed. An efficient access algorithm is applied to avoid both the data wavelengths and the receiver collisions. In our protocol, each access node is capable of transmitting and receiving over any of the data wavelengths, facing the scalability issues. Two different slot reuse schemes are assumed: the source and the destination stripping schemes. For both schemes, performance measures evaluation is provided via an analytic model. The analytical results are validated by a discrete event simulation model that uses Poisson traffic sources. Simulation results show that the proposed protocol manages efficient bandwidth utilization, especially under high load. Also, comparative simulation results prove that our protocol achieves significant performance improvement as compared with other WDMA protocols which restrict transmission over a dedicated data wavelength. Finally, performance measures evaluation is explored for diverse numbers of buffer size, access nodes and data wavelengths.

Problem-Matched Basis Functions for Microstrip Coupled Slot Antennas based on Transmission Line Greens Functions

NARCIS (Netherlands)

Bruni, S.; Llombart Juan, N.; Neto, A.; Gerini, G.; Maci, S.

2004-01-01

A general algorithm for the analysis of microstrip coupled leaky wave slot antennas was discussed. The method was based on the construction of physically appealing entire domain Methods of Moments (MoM) basis function that allowed a consistent reduction of the number of unknowns and of total

Silicon epitaxy on textured double layer porous silicon by LPCVD

International Nuclear Information System (INIS)

Cai Hong; Shen Honglie; Zhang Lei; Huang Haibin; Lu Linfeng; Tang Zhengxia; Shen Jiancang

2010-01-01

Epitaxial silicon thin film on textured double layer porous silicon (DLPS) was demonstrated. The textured DLPS was formed by electrochemical etching using two different current densities on the silicon wafer that are randomly textured with upright pyramids. Silicon thin films were then grown on the annealed DLPS, using low-pressure chemical vapor deposition (LPCVD). The reflectance of the DLPS and the grown silicon thin films were studied by a spectrophotometer. The crystallinity and topography of the grown silicon thin films were studied by Raman spectroscopy and SEM. The reflectance results show that the reflectance of the silicon wafer decreases from 24.7% to 11.7% after texturing, and after the deposition of silicon thin film the surface reflectance is about 13.8%. SEM images show that the epitaxial silicon film on textured DLPS exhibits random pyramids. The Raman spectrum peaks near 521 cm -1 have a width of 7.8 cm -1 , which reveals the high crystalline quality of the silicon epitaxy.

Finite Length Analysis of Irregular Repetition Slotted ALOHA in the Waterfall Region

OpenAIRE

Amat, Alexandre Graell i; Liva, Gianluigi

2018-01-01

A finite length analysis is introduced for irregular repetition slotted ALOHA (IRSA) that enables to accurately estimate its performance in the moderate-to-high packet loss probability regime, i.e., in the so-called waterfall region. The analysis is tailored to the collision channel model, which enables mapping the description of the successive interference cancellation process onto the iterative erasure decoding of low-density parity-check codes. The analysis provides accurate estimates of t...

Direct-phase-variable model of a synchronous reluctance motor including all slot and winding harmonics

International Nuclear Information System (INIS)

Obe, Emeka S.; Binder, A.

2011-01-01

A detailed model in direct-phase variables of a synchronous reluctance motor operating at mains voltage and frequency is presented. The model includes the stator and rotor slot openings, the actual winding layout and the reluctance rotor geometry. Hence, all mmf and permeance harmonics are taken into account. It is seen that non-negligible harmonics introduced by slots are present in the inductances computed by the winding function procedure. These harmonics are usually ignored in d-q models. The machine performance is simulated in the stator reference frame to depict the difference between this new direct-phase model including all harmonics and the conventional rotor reference frame d-q model. Saturation is included by using a polynomial fitting the variation of d-axis inductance with stator current obtained by finite-element software FEMAG DC (registered) . The detailed phase-variable model can yield torque pulsations comparable to those obtained from finite elements while the d-q model cannot.

Effect of Substrate Permittivity and Thickness on Performance of Single-Layer, Wideband, U-Slot Antennas on Microwave Substrates

National Research Council Canada - National Science Library

Natarajan, V; Chatterjee, D

2004-01-01

This paper presents effects of substrate permittivity and thickness on the performance characteristics like impedance bandwidth, radiation efficiency and gain of a single-layer, wideband, U-slot antenna...

Production of electronic grade lunar silicon by disproportionation of silicon difluoride

Science.gov (United States)

Agosto, William N.

1993-01-01

Waldron has proposed to extract lunar silicon by sodium reduction of sodium fluorosilicate derived from reacting sodium fluoride with lunar silicon tetrafluoride. Silicon tetrafluoride is obtained by the action of hydrofluoric acid on lunar silicates. While these reactions are well understood, the resulting lunar silicon is not likely to meet electronic specifications of 5 nines purity. Dale and Margrave have shown that silicon difluoride can be obtained by the action of silicon tetrafluoride on elemental silicon at elevated temperatures (1100-1200 C) and low pressures (1-2 torr). The resulting silicon difluoride will then spontaneously disproportionate into hyperpure silicon and silicon tetrafluoride in vacuum at approximately 400 C. On its own merits, silicon difluoride polymerizes into a tough waxy solid in the temperature range from liquid nitrogen to about 100 C. It is the silicon analog of teflon. Silicon difluoride ignites in moist air but is stable under lunar surface conditions and may prove to be a valuable industrial material that is largely lunar derived for lunar surface applications. The most effective driver for lunar industrialization may be the prospects for industrial space solar power systems in orbit or on the moon that are built with lunar materials. Such systems would require large quantities of electronic grade silicon or compound semiconductors for photovoltaics and electronic controls. Since silicon is the most abundant semimetal in the silicate portion of any solar system rock (approximately 20 wt percent), lunar silicon production is bound to be an important process in such a solar power project. The lunar silicon extraction process is discussed.

Fundamental imaging characteristics of a slot-scan digital chest radiographic system

International Nuclear Information System (INIS)

Samei, Ehsan; Saunders, Robert S.; Lo, Joseph Y.; Dobbins, James T. III; Jesneck, Jonathan L.; Floyd, Carey E.; Ravin, Carl E.

2004-01-01

Our purpose in this study was to evaluate the fundamental image quality characteristics of a new slot-scan digital chest radiography system (ThoraScan, Delft Imaging Systems/Nucletron, Veenendaal, The Netherlands). The linearity of the system was measured over a wide exposure range at 90, 117, and 140 kVp with added Al filtration. System uniformity and reproducibility were established with an analysis of images from repeated exposures. The modulation transfer function (MTF) was evaluated using an established edge method. The noise power spectrum (NPS) and the detective quantum efficiency (DQE) of the system were evaluated at the three kilo-voltages over a range of exposures. Scatter fraction (SF) measurements were made using a posterior beam stop method and a geometrical chest phantom. The system demonstrated excellent linearity, but some structured nonuniformities. The 0.1 MTF values occurred between 3.3-3.5 mm -1 . The DQE(0.15) and DQE(2.5) were 0.21 and 0.07 at 90 kVp, 0.18 and 0.05 at 117 kVp, and 0.16 and 0.03 at 140 kVp, respectively. The system exhibited remarkably lower SFs compared to conventional full-field systems with anti-scatter grid, measuring 0.13 in the lungs and 0.43 in the mediastinum. The findings indicated that the slot-scan design provides marked scatter reduction leading to high effective DQE (DQE eff ) of the system and reduced patient dose required to achieve high image quality

Spiral Slotted Microstrip Antenna Design for 700 MHz Band Application

Directory of Open Access Journals (Sweden)

Ricardo Meneses González

2016-01-01

Full Text Available This work describes the design and implementation of spiral slotted microstrip antenna. Recently, just like other countries, in Mexico, terrestrial digital television has been implemented (analogic shutdown; as a consequence, the 700 MHz UFH Band (698–806 MHz has been opened to new telecommunications services, particularly wireless mobile communication. This technological advance represents a radio mobile antenna design challenge because it is necessary to design an antenna whose dimensions must be small enough, which satisfies gain, resonance frequency, and bandwidth requirements and is of low cost.

Modeling of Coaxial Slot Waveguides Using Analytical and Numerical Approaches: Revisited

Directory of Open Access Journals (Sweden)

Kok Yeow You

2012-01-01

Full Text Available Our reviews of analytical methods and numerical methods for coaxial slot waveguides are presented. The theories, background, and physical principles related to frequency-domain electromagnetic equations for coaxial waveguides are reassessed. Comparisons of the accuracies of various types of admittance and impedance equations and numerical simulations are made, and the fringing field at the aperture sensor, which is represented by the lumped capacitance circuit, is evaluated. The accuracy and limitations of the analytical equations are explained in detail. The reasons for the replacement of analytical methods by numerical methods are outlined.

Cogging Torque Reduction in Brushless DC Motors Using Slot-Opening Shift

Directory of Open Access Journals (Sweden)

SAIED, S. A.

2009-02-01

Full Text Available In this paper, two new methods for the stator skew are introduced. In contrary with the conventional stator skew, this paper is concentrate on the slot-opening skew. The simula-tion result by finite element shows a considerable reduction in the cogging torque of the motors, the new methods are applied to. Moreover the simulations justify that the back-EMF shape remains trapezoidal for various skew angles in contrary with that in the conventional skew, this fact makes the method highly applicable in BLDC motors.

Colloidal characterization of ultrafine silicon carbide and silicon nitride powders

Science.gov (United States)

Whitman, Pamela K.; Feke, Donald L.

1986-01-01

The effects of various powder treatment strategies on the colloid chemistry of aqueous dispersions of silicon carbide and silicon nitride are examined using a surface titration methodology. Pretreatments are used to differentiate between the true surface chemistry of the powders and artifacts resulting from exposure history. Silicon nitride powders require more extensive pretreatment to reveal consistent surface chemistry than do silicon carbide powders. As measured by titration, the degree of proton adsorption from the suspending fluid by pretreated silicon nitride and silicon carbide powders can both be made similar to that of silica.

Investigation of a 7-pole/6-slot Halbach-magnetized permanent-magnet linear alternator used for free-piston stirling engines

Science.gov (United States)

Zheng, Ping; Tong, Chengde; Zhao, Jing; Yu, Bin; Li, Lin; Bai, Jingang; Zhang, Lu

2012-04-01

This paper investigates a 7-pole/6-slot Halbach-magnetized permanent-magnet linear alternator used for free piston Stirling engines (FPSEs). Taking the advantages of Halbach array, a 1 kW prototype alternator is designed. Considering the rms value of electromotive force (EMF) and harmonic distortion, the optimal length ratio of the axial- and radial-magnetized permanent magnets and thicknesses of the permanent magnets are optimized by 2D finite element method. The alternator detent force, which is an important factor for smooth operation of FPSEs, is studied by optimizing slot tip and end tooth. The load and thermal performances of the final design are simulated. A prototype alternator was designed, built and tested. Experimental data indicated satisfactory design.

Wearable Passive E-Textile UHF RFID Tag Based on a Slotted Patch Antenna with Sewn Ground and Microchip Interconnections

Directory of Open Access Journals (Sweden)

Johanna Virkki

2017-01-01

Full Text Available We present a wearable passive UHF RFID tag based on a slotted patch antenna comprising only textile materials (e-textile, textile substrate, and conductive yearn. As a novel manufacturing approach, we realize the patch-to-ground and antenna-to-IC interfaces using only conductive thread and a sewing machine. We outline the electromagnetic optimization of the antenna for body-worn operation through simulations and present a performance comparison between the e-textile tag and a tag produced using regular electronics materials and methods. The measured results show that the textile tag achieves the electrical performance required in practical applications and that the slotted patch type antenna provides stable electromagnetic performance in different body-worn configurations.

Analytical and numerical calculation of magnetic field distribution in the slotted air-gap of tangential surface permanent-magnet motors

Directory of Open Access Journals (Sweden)

Boughrara Kamel

2009-01-01

Full Text Available This paper deals with the analytical and numerical analysis of the flux density distribution in the slotted air gap of permanent magnet motors with surface mounted tangentially magnetized permanent magnets. Two methods for magnetostatic field calculations are developed. The first one is an analytical method in which the effect of stator slots is taken into account by modulating the magnetic field distribution by the complex relative air gap permeance. The second one is a numerical method using 2-D finite element analysis with consideration of Dirichlet and anti-periodicity (periodicity boundary conditions and Lagrange Multipliers for simulation of movement. The results obtained by the analytical method are compared to the results of finite-element analysis.

Two-Element Tapered Slot Antenna Array for Terahertz Resonant Tunneling Diode Oscillators

Directory of Open Access Journals (Sweden)

Jianxiong Li

2014-01-01

Full Text Available Two-element tapered slot antenna (TSA array for terahertz (THz resonant tunneling diode (RTD oscillators is proposed in this paper. The proposed TSA array has the advantages of both the high directivity and high gain at the horizontal direction and hence can facilitate the horizontal communication between the RTD oscillators and other integrated circuit chips. A MIM (metal-insulator-metal stub with a T-shaped slot is used to reduce the mutual coupling between the TSA elements. The validity and feasibility of the proposed TSA array have been simulated and analyzed by the ANSYS/ANSOFT’s High Frequency Structure Simulator (HFSS. Detailed modeling approaches and theoretical analysis of the proposed TSA array have been fully addressed. The simulation results show that the mutual coupling between the TSA elements is reduced below −40 dB. Furthermore, at 500 GHz, the directivity, the gain, and the half power beam width (HPBW at the E-plane of the proposed TSA array are 12.18 dB, 13.09 dB, and 61°, respectively. The proposed analytical method and achieved performance are very promising for the antenna array integrated with the RTD oscillators at the THz frequency and could pave the way to the design of the THz antenna array for the RTD oscillators.

The allure of multi-line games in modern slot machines.

Science.gov (United States)

Dixon, Mike J; Graydon, Candice; Harrigan, Kevin A; Wojtowicz, Lisa; Siu, Vivian; Fugelsang, Jonathan A

2014-11-01

In multi-line slot machines, players can wager on more than one line per spin. We sought to show that players preferred multi-line over single-line games, and that certain game features could cause multi-line game play to feel more rewarding. Reward was measured using post-reinforcement pauses (PRPs) following each outcome (the time between outcome delivery and the next spin). Gamblers (n = 102) played 250 spins on a 20-line game and 250 spins on a one-line game (answering questions about game experiences following each session). Playing one-line, a small credit gain (e.g. 2 cents) was a net win. In the 20-line game it was a net loss of 18 credits but was still accompanied by 'winning' sights and sounds. Most players (94%) preferred the 20-line game. PRPs for small credit gains (net losses) in the 20-line game were equivalent, or larger than in the one-line game where such gains were wins. The largest increase in PRP size was between the 0 and 2 credit conditions for both games. Thus 20-line players reacted as though these net losses of 18 credits were rewarding. Players' estimates of the number of true wins were accurate in the one-line game, but they significantly over-estimated the number of true wins in the 20-line game (P game play. Multi-line games appear to be more appealing to gaming machine ('slots') players than single-line games. These games may be particularly absorbing for those with gambling problems. © 2014 Society for the Study of Addiction.

Arsenic implantation into polycrystalline silicon and diffusion to silicon substrate

International Nuclear Information System (INIS)

Tsukamoto, K.; Akasaka, Y.; Horie, K.

1977-01-01

Arsenic implantation into polycrystalline silicon and drive-in diffusion to silicon substrate have been investigated by MeV He + backscattering analysis and also by electrical measurements. The range distributions of arsenic implanted into polycrystalline silicon are well fitted to Gaussian distributions over the energy range 60--350 keV. The measured values of R/sub P/ and ΔR/sub P/ are about 10 and 20% larger than the theoretical predictions, respectively. The effective diffusion coefficient of arsenic implanted into polycrystalline silicon is expressed as D=0.63 exp[(-3.22 eV/kT)] and is independent of the arsenic concentration. The drive-in diffusion of arsenic from the implanted polycrystalline silicon layer into the silicon substrate is significantly affected by the diffusion atmosphere. In the N 2 atmosphere, a considerable amount of arsenic atoms diffuses outward to the ambient. The outdiffusion can be suppressed by encapsulation with Si 3 N 4 . In the oxidizing atmosphere, arsenic atoms are driven inward by growing SiO 2 due to the segregation between SiO 2 and polycrystalline silicon, and consequently the drive-in diffusion of arsenic is enhanced. At the interface between the polycrystalline silicon layer and the silicon substrate, arsenic atoms are likely to segregate at the polycrystalline silicon side

Circularly Polarized Slotted Microstrip Patch Antenna with Finite Ground Plane

Directory of Open Access Journals (Sweden)

Sanyog Rawat

2012-12-01

Full Text Available In this paper a new geometry of circularly polarized patch antenna is proposed with improved bandwidth. The radiation performance of proposed patch antenna is investigated using IE3D simulation software and its performance is compared with that of conventional rectangular patch antenna. The simulated return loss, axial ratio and impedance with frequency for the proposed antenna are reported in this paper. It is shown that by selecting suitable ground-plane dimensions, air gap and location of the slots, the impedance bandwidth can be enhanced upto 10.15% as compared to conventional rectangular patch (4.24% with an axial ratio bandwidth of 4.05%.

Pulsar Polar Cap and Slot Gap Models: Confronting Fermi Data

Directory of Open Access Journals (Sweden)

Alice K. Harding

2013-09-01

Full Text Available Rotation-powered pulsars are excellent laboratories for studying particle acceleration as well as fundamental physics of strong gravity, strong magnetic fields and relativity. Particle acceleration and high-energy emission from the polar caps is expected to occur in connection with electron-positron pair cascades. I will review acceleration and gamma-ray emission from the pulsar polar cap and associated slot gap. Predictions of these models can be tested with the data set on pulsars collected by the Large Area Telescope on the Fermi Gamma-Ray Telescope over the last four years, using both detailed light curve fitting, population synthesis and phase-resolved spectroscopy.

Porous silicon: silicon quantum dots for photonic applications

International Nuclear Information System (INIS)

Pavesi, L.; Guardini, R.

1996-01-01

Porous silicon formation and structure characterization are briefly illustrated. Its luminescence properties rae presented and interpreted on the basis of exciton recombination in quantum dot structures: the trap-controlled hopping mechanism is used to describe the recombination dynamics. Porous silicon application to photonic devices is considered: porous silicon multilayer in general, and micro cavities in particular are described. The present situation in the realization of porous silicon LEDs is considered, and future developments in this field of research are suggested. (author). 30 refs., 30 figs., 13 tabs

Green's function of an infinite slot printed between two homogeneous dielectrics - Part II: Uniform asymptotic solution

NARCIS (Netherlands)

Maci, S.; Neto, A.

2004-01-01

This second part of a two-paper sequence deals with the uniform asymptotic description of the Green's function of an infinite slot printed between two different homogeneous dielectric media. Starting from the magnetic current derived in Part I, the dyadic green's function is first formulated in

An Integrated 4-element Slot-Based MIMO and an UWB Sensing Antenna System for CR Platforms

KAUST Repository

Hussain, Rifaqat; Sharawi, Mohammad S.; Shamim, Atif

2017-01-01

This paper presents a novel integrated antenna system for cognitive radio (CR) applications. The design consists of a compact 4- element reconfigurable annular slot based multiple-input-multiple-output (MIMO) antenna system integrated within an ultra-wide-band (UWB) sensing antenna. All the antenna elements are planar in structure and designed on a single substrate (RO-4350) with dimensions 60×120×1.5 mm3. The frequency reconfigurable slot based MIMO antenna system is tuned over a wide frequency band from 1.77 GHz to 2.51 GHz while the UWB sensing antenna is covering from 0.75~7.65 GHz The proposed antenna system is suitable for CR enabled wireless devices. The envelope correlation coefficient (ECC) did not exceed 0.248 in the entire operating band of the MIMO antenna part. The maximum measured gain of the MIMO antenna is 3.2 dBi with maximum efficiency of 81%.

An Integrated 4-element Slot-Based MIMO and an UWB Sensing Antenna System for CR Platforms

KAUST Repository

Hussain, Rifaqat

2017-12-08

This paper presents a novel integrated antenna system for cognitive radio (CR) applications. The design consists of a compact 4- element reconfigurable annular slot based multiple-input-multiple-output (MIMO) antenna system integrated within an ultra-wide-band (UWB) sensing antenna. All the antenna elements are planar in structure and designed on a single substrate (RO-4350) with dimensions 60×120×1.5 mm3. The frequency reconfigurable slot based MIMO antenna system is tuned over a wide frequency band from 1.77 GHz to 2.51 GHz while the UWB sensing antenna is covering from 0.75~7.65 GHz The proposed antenna system is suitable for CR enabled wireless devices. The envelope correlation coefficient (ECC) did not exceed 0.248 in the entire operating band of the MIMO antenna part. The maximum measured gain of the MIMO antenna is 3.2 dBi with maximum efficiency of 81%.

Silicon-Rich Silicon Carbide Hole-Selective Rear Contacts for Crystalline-Silicon-Based Solar Cells.

Science.gov (United States)

Nogay, Gizem; Stuckelberger, Josua; Wyss, Philippe; Jeangros, Quentin; Allebé, Christophe; Niquille, Xavier; Debrot, Fabien; Despeisse, Matthieu; Haug, Franz-Josef; Löper, Philipp; Ballif, Christophe

2016-12-28

The use of passivating contacts compatible with typical homojunction thermal processes is one of the most promising approaches to realizing high-efficiency silicon solar cells. In this work, we investigate an alternative rear-passivating contact targeting facile implementation to industrial p-type solar cells. The contact structure consists of a chemically grown thin silicon oxide layer, which is capped with a boron-doped silicon-rich silicon carbide [SiC x (p)] layer and then annealed at 800-900 °C. Transmission electron microscopy reveals that the thin chemical oxide layer disappears upon thermal annealing up to 900 °C, leading to degraded surface passivation. We interpret this in terms of a chemical reaction between carbon atoms in the SiC x (p) layer and the adjacent chemical oxide layer. To prevent this reaction, an intrinsic silicon interlayer was introduced between the chemical oxide and the SiC x (p) layer. We show that this intrinsic silicon interlayer is beneficial for surface passivation. Optimized passivation is obtained with a 10-nm-thick intrinsic silicon interlayer, yielding an emitter saturation current density of 17 fA cm -2 on p-type wafers, which translates into an implied open-circuit voltage of 708 mV. The potential of the developed contact at the rear side is further investigated by realizing a proof-of-concept hybrid solar cell, featuring a heterojunction front-side contact made of intrinsic amorphous silicon and phosphorus-doped amorphous silicon. Even though the presented cells are limited by front-side reflection and front-side parasitic absorption, the obtained cell with a V oc of 694.7 mV, a FF of 79.1%, and an efficiency of 20.44% demonstrates the potential of the p + /p-wafer full-side-passivated rear-side scheme shown here.

Dynamic Channel Slot Allocation Scheme and Performance Analysis of Cyclic Quorum Multichannel MAC Protocol

Directory of Open Access Journals (Sweden)

Xing Hu

2017-01-01

Full Text Available In high diversity node situation, multichannel MAC protocol can improve the frequency efficiency, owing to fewer collisions compared with single-channel MAC protocol. And the performance of cyclic quorum-based multichannel (CQM MAC protocol is outstanding. Based on cyclic quorum system and channel slot allocation, it can avoid the bottleneck that others suffered from and can be easily realized with only one transceiver. To obtain the accurate performance of CQM MAC protocol, a Markov chain model, which combines the channel-hopping strategy of CQM protocol and IEEE 802.11 distributed coordination function (DCF, is proposed. The results of numerical analysis show that the optimal performance of CQM protocol can be obtained in saturation bound situation. And then we obtain the saturation bound of CQM system by bird swarm algorithm. In addition, to improve the performance of CQM protocol in unsaturation situation, a dynamic channel slot allocation of CQM (DCQM protocol is proposed, based on wavelet neural network. Finally, the performance of CQM protocol and DCQM protocol is simulated by Qualnet platform. And the simulation results show that the analytic and simulation results match very well; the DCQM performs better in unsaturation situation.

Investigation of New Microstrip Bandpass Filter Based on Patch Resonator with Geometrical Fractal Slot.

Directory of Open Access Journals (Sweden)

Yaqeen S Mezaal

Full Text Available A compact dual-mode microstrip bandpass filter using geometrical slot is presented in this paper. The adopted geometrical slot is based on first iteration of Cantor square fractal curve. This filter has the benefits of possessing narrower and sharper frequency responses as compared to microstrip filters that use single mode resonators and traditional dual-mode square patch resonators. The filter has been modeled and demonstrated by Microwave Office EM simulator designed at a resonant frequency of 2 GHz using a substrate of εr = 10.8 and thickness of h = 1.27 mm. The output simulated results of the proposed filter exhibit 22 dB return loss, 0.1678 dB insertion loss and 12 MHz bandwidth in the passband region. In addition to the narrow band gained, miniaturization properties as well as weakened spurious frequency responses and blocked second harmonic frequency in out of band regions have been acquired. Filter parameters including insertion loss, return loss, bandwidth, coupling coefficient and external quality factor have been compared with different values of perturbation dimension (d. Also, a full comparative study of this filter as compared with traditional square patch filter has been considered.

A CdZnTe slot-scanned detector for digital mammography

International Nuclear Information System (INIS)

Mainprize, James G.; Ford, Nancy L.; Yin Shi; Gordon, Eli E.; Hamilton, William J.; Tuemer, Tuemay O.; Yaffe, Martin J.

2002-01-01

A new high-resolution detector has been developed for use in a slot-scanned digital mammography system. The detector is a hybrid device that consists of a CCD operating in time-delay integration mode that is bonded to a 150-μm-thick CdZnTe photoconductor array. The CCD was designed with a detector element pitch of 50 μm. Two devices were evaluated with differing crystalline quality. Incomplete charge collection was a source of reduction in DQE. This occurs in both devices due to characteristically low mobility-lifetime products for CdZnTe, with the greatest losses demonstrated by the multicrystalline sample. The mobility-lifetime products for the multicrystalline device were found to be 2.4x10 -4 and 4.0x10 -7 cm 2 /V for electrons and holes, respectively. The device constructed with higher quality single crystal CdZnTe demonstrated mobility-lifetime products of 1.0x10 -4 and 4.4x10 -6 cm 2 /V for electrons and holes. The MTF and DQE for the device were measured at several exposures and results were compared to predictions from a linear systems model of signal and noise propagation. The MTF at a spatial frequency of 10 mm -1 exceeded 0.18 and 0.56 along the scan and slot directions, respectively. Scanning motion and CCD design limited the resolution along the scan direction. For an x-ray beam from a tungsten target tube with 40 μm molybdenum filtration operated at 26 kV, the single crystal device demonstrated a DQE(0) of 0.70±0.02 at 7.1x10 -6 C/kg (27 mR) exposure to the detector, despite its relatively poor charge collection efficiency

Geochemistry of silicon isotopes

Energy Technology Data Exchange (ETDEWEB)

Ding, Tiping; Li, Yanhe; Gao, Jianfei; Hu, Bin [Chinese Academy of Geological Science, Beijing (China). Inst. of Mineral Resources; Jiang, Shaoyong [China Univ. of Geosciences, Wuhan (China).

2018-04-01

Silicon is one of the most abundant elements in the Earth and silicon isotope geochemistry is important in identifying the silicon source for various geological bodies and in studying the behavior of silicon in different geological processes. This book starts with an introduction on the development of silicon isotope geochemistry. Various analytical methods are described and compared with each other in detail. The mechanisms of silicon isotope fractionation are discussed, and silicon isotope distributions in various extraterrestrial and terrestrial reservoirs are updated. Besides, the applications of silicon isotopes in several important fields are presented.

Distributed Channel Allocation and Time Slot Optimization for Green Internet of Things

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Kaiqi Ding

2017-10-01

Full Text Available In sustainable smart cities, power saving is a severe challenge in the energy-constrained Internet of Things (IoT. Efficient utilization of limited multiple non-overlap channels and time resources is a promising solution to reduce the network interference and save energy consumption. In this paper, we propose a joint channel allocation and time slot optimization solution for IoT. First, we propose a channel ranking algorithm which enables each node to rank its available channels based on the channel properties. Then, we propose a distributed channel allocation algorithm so that each node can choose a proper channel based on the channel ranking and its own residual energy. Finally, the sleeping duration and spectrum sensing duration are jointly optimized to maximize the normalized throughput and satisfy energy consumption constraints simultaneously. Different from the former approaches, our proposed solution requires no central coordination or any global information that each node can operate based on its own local information in a total distributed manner. Also, theoretical analysis and extensive simulations have validated that when applying our solution in the network of IoT: (i each node can be allocated to a proper channel based on the residual energy to balance the lifetime; (ii the network can rapidly converge to a collision-free transmission through each node’s learning ability in the process of the distributed channel allocation; and (iii the network throughput is further improved via the dynamic time slot optimization.

Distributed Channel Allocation and Time Slot Optimization for Green Internet of Things.

Science.gov (United States)

Ding, Kaiqi; Zhao, Haitao; Hu, Xiping; Wei, Jibo

2017-10-28

In sustainable smart cities, power saving is a severe challenge in the energy-constrained Internet of Things (IoT). Efficient utilization of limited multiple non-overlap channels and time resources is a promising solution to reduce the network interference and save energy consumption. In this paper, we propose a joint channel allocation and time slot optimization solution for IoT. First, we propose a channel ranking algorithm which enables each node to rank its available channels based on the channel properties. Then, we propose a distributed channel allocation algorithm so that each node can choose a proper channel based on the channel ranking and its own residual energy. Finally, the sleeping duration and spectrum sensing duration are jointly optimized to maximize the normalized throughput and satisfy energy consumption constraints simultaneously. Different from the former approaches, our proposed solution requires no central coordination or any global information that each node can operate based on its own local information in a total distributed manner. Also, theoretical analysis and extensive simulations have validated that when applying our solution in the network of IoT: (i) each node can be allocated to a proper channel based on the residual energy to balance the lifetime; (ii) the network can rapidly converge to a collision-free transmission through each node's learning ability in the process of the distributed channel allocation; and (iii) the network throughput is further improved via the dynamic time slot optimization.

Development of an Architecture of Sun-Synchronous Orbital Slots to Minimize Conjunctions

Science.gov (United States)

Weeden, B.

Sun-synchronous orbit (SSO) satellites serve many important functions, primarily in the areas of Earth reconnaissance and weather. The orbital parameters of altitude, inclination and right ascension which allow for the unique utility of Sun-sync orbit limit these satellites to a very specific region of space. The popularity of these satellite missions combined with the use of similar engineering solutions has resulted in the majority of current Sun-sync satellites within this region having very similar inclinations and altitudes while also spaced around the Equator in right ascension, creating the opportunity for conjunctions at the polar crossing points and a serious safety issue that could endanger long-term sustainability of SSO. This paper outlines the development of a new architecture of SSO zoning to create specific slots separating SSO satellites in altitude, right ascension and time at all orbital intersections while minimizing the limitations on utility. A methodical approach for the development of the system is presented along with the work-to-date and a software tool for calculating repeating ground track orbits. The slot system is intended to allow for continued utility of and safe operation within SSO while greatly decreasing the chance of collisions at orbital intersections. This architecture is put forward as one possible element of a new Space Traffic Management (STM) system with the overall goal of maintaining the safe and continued used of space by all actors.

Investigation of 0.38 THz backward-wave oscillator based on slotted sine waveguide and pencil electron beam

Energy Technology Data Exchange (ETDEWEB)

Zhang, Luqi; Wei, Yanyu; Wang, Bing; Shen, Wenan; Xu, Jin; Gong, Yubin [National Key Laboratory of Science and Technology on Vacuum Electronics, School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China); Park, Gun-Sik [The Department of Physics and Astronomy, Seoul National University, Seoul 151-747 (Korea, Republic of)

2016-03-15

A novel backward wave oscillator (BWO) is presented by utilizing a slotted sine waveguide with a pencil electron beam to produce the high power terahertz wave. The high frequency characteristics including dispersion properties, interaction impedances, and transmission characteristics of the slotted sine waveguide are analyzed in detail. The high frequency system including the output coupler, slow wave structure (SWS), and reflector are designed properly. A 3-D particle-in-cell mode is applied to predict the device performance of the BWO based on the novel SWS. The investigation results demonstrate that this device can generate over 8.05 W output power in the frequency range of 363.4–383.8 GHz by using a 30 mA pencil electron beam and adjusting the beam voltage from 20 kV to 32 kV.

Silicon heterojunction transistor

International Nuclear Information System (INIS)

Matsushita, T.; Oh-uchi, N.; Hayashi, H.; Yamoto, H.

1979-01-01

SIPOS (Semi-insulating polycrystalline silicon) which is used as a surface passivation layer for highly reliable silicon devices constitutes a good heterojunction for silicon. P- or B-doped SIPOS has been used as the emitter material of a heterojunction transistor with the base and collector of silicon. An npn SIPOS-Si heterojunction transistor showing 50 times the current gain of an npn silicon homojunction transistor has been realized by high-temperature treatments in nitrogen and low-temperature annealing in hydrogen or forming gas

Partially slotted crystals for a high-resolution γ-camera based on a position sensitive photomultiplier

International Nuclear Information System (INIS)

Giokaris, N.; Loudos, G.; Maintas, D.; Karabarbounis, A.; Lembesi, M.; Spanoudaki, V.; Stiliaris, E.; Boukis, S.; Gektin, A.; Pedash, V.; Gayshan, V.

2005-01-01

Partially slotted crystals have been designed and constructed and have been used to evaluate the performance with respect to the spatial resolution of a γ-camera based on a position-sensitive photomultiplier. It is shown that the resolution obtained with such a crystal is only slightly worse than the one obtained with a fully pixelized one whose cost, however, is much higher

Composição química e aspecto superficial do slot de braquetes metálicos Elemental composition and superficial aspect of metallic brackets slot

Directory of Open Access Journals (Sweden)

Tatiana Féres Assad-Loss

2008-06-01

Full Text Available OBJETIVO: avaliar a composição química e rugosidade do fundo do slot de 90 braquetes metálicos divididos em 9 grupos: grupo 1- aço inoxidável (Equilibrium 2 - Dentaurum; grupo 2 - titânio (Equilibrium ti - Dentaurum; grupo 3- cromo-cobalto (Topic- Dentaurum; grupo 4 - aço inoxidável (Standard -TP Orthodontics; grupo 5 - aço inoxidável (Serie light - American Orthodontics; grupo 6 - aço inoxidável (Kirium Line - Abzil Lancer; grupo 7 - aço inoxidável livre de níquel (Monobloc - Morelli; grupo 8 - aço inoxidável (Convencional- Morelli e grupo 9 - aço inoxidável livre de níquel (Monobloc Golden - Morelli. METODOLOGIA: a composição química foi analisada pela Espectroscopia de Energia Dispersiva. A avaliação qualitativa do fundo do slot foi realizada através do MEV classificada de 0 a 8, correspondente às características da superfície. RESULTADOS: composição química - grupo 1 = titânio puro; grupo 9 = recoberto por nitreto de titânio em 99,48%; grupo 3 = cromo-cobalto; grupo 8 = aço inoxidável livre de níquel. Os demais grupos são compostos de aço inoxidável. Avaliação da superfície - grupo 1 = valor 2 (superfície mais polida; grupos 2, 5 e 7 = valor 3 (aspecto de polimento; grupos 3, 8 e 9 = valor 6 (menor polimento; grupo 4 = valor 6,5 (maior rugosidade e o grupo 6 = valor 5 (características intermediárias de polimento. CONCLUSÕES: os braquetes metálicos são compostos de diferentes ligas e estão disponíveis com baixo conteúdo ou ausência de níquel. Os braquetes de titânio apresentaram polimento semelhante aos de aço inoxidável, porém os recobertos por nitreto de titânio e os de cromo-cobalto mostraram superfície mais irregular ou menos polida.AIM: To evaluate the elemental composition and the slot roughness of 90 metallic brackets divided into 9 groups: group 1 - stainless steel (Equilibrium 2 - Dentaurum; group 2 - titanium (Equilibrium ti - Dentaurum; group 3 - chromium-cobalt (Topic

Vertical integration of high-Q silicon nitride microresonators into silicon-on-insulator platform.

Science.gov (United States)

Li, Qing; Eftekhar, Ali A; Sodagar, Majid; Xia, Zhixuan; Atabaki, Amir H; Adibi, Ali

2013-07-29

We demonstrate a vertical integration of high-Q silicon nitride microresonators into the silicon-on-insulator platform for applications at the telecommunication wavelengths. Low-loss silicon nitride films with a thickness of 400 nm are successfully grown, enabling compact silicon nitride microresonators with ultra-high intrinsic Qs (~ 6 × 10(6) for 60 μm radius and ~ 2 × 10(7) for 240 μm radius). The coupling between the silicon nitride microresonator and the underneath silicon waveguide is based on evanescent coupling with silicon dioxide as buffer. Selective coupling to a desired radial mode of the silicon nitride microresonator is also achievable using a pulley coupling scheme. In this work, a 60-μm-radius silicon nitride microresonator has been successfully integrated into the silicon-on-insulator platform, showing a single-mode operation with an intrinsic Q of 2 × 10(6).

Analytical and Experimental Evaluation of Joining Silicon Carbide to Silicon Carbide and Silicon Nitride to Silicon Nitride for Advanced Heat Engine Applications Phase II

Energy Technology Data Exchange (ETDEWEB)

Sundberg, G.J.

1994-01-01

Techniques were developed to produce reliable silicon nitride to silicon nitride (NCX-5101) curved joins which were used to manufacture spin test specimens as a proof of concept to simulate parts such as a simple rotor. Specimens were machined from the curved joins to measure the following properties of the join interlayer: tensile strength, shear strength, 22 C flexure strength and 1370 C flexure strength. In parallel, extensive silicon nitride tensile creep evaluation of planar butt joins provided a sufficient data base to develop models with accurate predictive capability for different geometries. Analytical models applied satisfactorily to the silicon nitride joins were Norton's Law for creep strain, a modified Norton's Law internal variable model and the Monkman-Grant relationship for failure modeling. The Theta Projection method was less successful. Attempts were also made to develop planar butt joins of siliconized silicon carbide (NT230).

AMELIA CESTOL Test: Acoustic Characteristics of Circulation Control Wing with Leading- and Trailing-Edge Slot Blowing

Science.gov (United States)

Horne, William C.; Burnside, Nathan J.

2013-01-01

The AMELIA Cruise-Efficient Short Take-off and Landing (CESTOL) configuration concept was developed to meet future requirements of reduced field length, noise, and fuel burn by researchers at Cal Poly, San Luis Obispo and Georgia Tech Research Institute under sponsorship by the NASA Fundamental Aeronautics Program (FAP), Subsonic Fixed Wing Project. The novel configuration includes leading- and trailing-edge circulation control wing (CCW), over-wing podded turbine propulsion simulation (TPS). Extensive aerodynamic measurements of forces, surfaces pressures, and wing surface skin friction measurements were recently measured over a wide range of test conditions in the Arnold Engineering Development Center(AEDC) National Full-Scale Aerodynamics Complex (NFAC) 40- by 80-Ft Wind Tunnel. Acoustic measurements of the model were also acquired for each configuration with 7 fixed microphones on a line under the left wing, and with a 48-element, 40-inch diameter phased microphone array under the right wing. This presentation will discuss acoustic characteristics of the CCW system for a variety of tunnel speeds (0 to 120 kts), model configurations (leading edge(LE) and/or trailing-edge(TE) slot blowing, and orientations (incidence and yaw) based on acoustic measurements acquired concurrently with the aerodynamic measurements. The flow coefficient, Cmu= mVSLOT/qSW varied from 0 to 0.88 at 40 kts, and from 0 to 0.15 at 120 kts. Here m is the slot mass flow rate, VSLOT is the slot exit velocity, q is dynamic pressure, and SW is wing surface area. Directivities at selected 1/3 octave bands will be compared with comparable measurements of a 2-D wing at GTRI, as will as microphone array near-field measurements of the right wing at maximum flow rate. The presentation will include discussion of acoustic sensor calibrations as well as characterization of the wind tunnel background noise environment.

Electrical leakage phenomenon in heteroepitaxial cubic silicon carbide on silicon

Science.gov (United States)

Pradeepkumar, Aiswarya; Zielinski, Marcin; Bosi, Matteo; Verzellesi, Giovanni; Gaskill, D. Kurt; Iacopi, Francesca

2018-06-01

Heteroepitaxial 3C-SiC films on silicon substrates are of technological interest as enablers to integrate the excellent electrical, electronic, mechanical, thermal, and epitaxial properties of bulk silicon carbide into well-established silicon technologies. One critical bottleneck of this integration is the establishment of a stable and reliable electronic junction at the heteroepitaxial interface of the n-type SiC with the silicon substrate. We have thus investigated in detail the electrical and transport properties of heteroepitaxial cubic silicon carbide films grown via different methods on low-doped and high-resistivity silicon substrates by using van der Pauw Hall and transfer length measurements as test vehicles. We have found that Si and C intermixing upon or after growth, particularly by the diffusion of carbon into the silicon matrix, creates extensive interstitial carbon traps and hampers the formation of a stable rectifying or insulating junction at the SiC/Si interface. Although a reliable p-n junction may not be realistic in the SiC/Si system, we can achieve, from a point of view of the electrical isolation of in-plane SiC structures, leakage suppression through the substrate by using a high-resistivity silicon substrate coupled with deep recess etching in between the SiC structures.

Fluorescence and thermoluminescence in silicon oxide films rich in silicon

International Nuclear Information System (INIS)

Berman M, D.; Piters, T. M.; Aceves M, M.; Berriel V, L. R.; Luna L, J. A.

2009-10-01

In this work we determined the fluorescence and thermoluminescence (TL) creation spectra of silicon rich oxide films (SRO) with three different silicon excesses. To study the TL of SRO, 550 nm of SRO film were deposited by Low Pressure Chemical Vapor Deposition technique on N-type silicon substrates with resistivity in the order of 3 to 5 Ω-cm with silicon excess controlled by the ratio of the gases used in the process, SRO films with Ro= 10, 20 and 30 (12-6% silicon excess) were obtained. Then, they were thermally treated in N 2 at high temperatures to diffuse and homogenize the silicon excess. In the fluorescence spectra two main emission regions are observed, one around 400 nm and one around 800 nm. TL creation spectra were determined by plotting the integrated TL intensity as function of the excitation wavelength. (Author)

Buried oxide layer in silicon

Science.gov (United States)

Sadana, Devendra Kumar; Holland, Orin Wayne

2001-01-01

A process for forming Silicon-On-Insulator is described incorporating the steps of ion implantation of oxygen into a silicon substrate at elevated temperature, ion implanting oxygen at a temperature below 200.degree. C. at a lower dose to form an amorphous silicon layer, and annealing steps to form a mixture of defective single crystal silicon and polycrystalline silicon or polycrystalline silicon alone and then silicon oxide from the amorphous silicon layer to form a continuous silicon oxide layer below the surface of the silicon substrate to provide an isolated superficial layer of silicon. The invention overcomes the problem of buried isolated islands of silicon oxide forming a discontinuous buried oxide layer.

A TURBO-GENERATOR DESIGN SYNTHESIS BASED ON THE NUMERICAL-FIELD CALCULATIONS AT VARYING THE NUMBER OF STATOR SLOTS

Directory of Open Access Journals (Sweden)

V. I. Milykh

2016-12-01

Full Text Available Purpose. The work is dedicated to the presentation of the principle of construction and implementation of an automated synthesis system of the turbo-generator (TG electromagnetic system in the case of its modernization. This is done on the example of changing the number of the stator core slots. Methodology. The basis of the synthesis is a TG basic construction. Its structure includes the mathematical and physical-geometrical models, as well as the calculation model for the FEMM software environment, providing the numerical calculations of the magnetic fields and electromagnetic parameters of TG. The mathematical model links the changing and basic dimensions and parameters of the electromagnetic system, provided that the TG power parameters are ensured. The physical-geometrical model is the geometric mapping of the electromagnetic system with the specified physical properties of its elements. This model converts the TG electromagnetic system in a calculation model for the FEMM program. Results. Testing of the created synthesis system is carried out on the example of the 340 MW TG. The geometric, electromagnetic and power parameters of its basic construction and its new variants at the different numbers of the stator slots are compared. The harmonic analysis of the temporal function of the stator winding EMF is also made for the variants being compared. Originality. The mathematical model, relating the new and base parameters of TG at the changing of the number of the stator slots is created. A Lua script, providing the numerical-field calculations of the TG electromagnetic parameters in the FEMM software environment is worked out. Construction of the constructive and calculation models, the numerical-field calculations and delivery of results are performed by a computer automatically, that ensures high efficiency of the TG design process. Practical value. The considered version of the TG modernization on the example of changing the number of the

Frequency of gambling problems among parents of pathological, versus nonpathological, casino gamblers using slot machines.

Science.gov (United States)

Versini, Audrey; LeGauffre, Cindy; Romo, Lucia; Adès, Jean; Gorwood, Philip

2012-01-01

Familial and twin studies suggest the implication of a genetic factor in pathological gambling, but mainly assess probands through treatment settings or advertisements. The question raised here is: are parents of casino pathological gamblers using slot machines more affected with pathological gambling than nonpathological gamblers, all interviewed on site at the same casino? Three hundred and fifty-five casino gamblers on slot machines, which included 96 pathological gamblers, 116 problem gamblers, and 143 nonproblem gamblers, were recruited in situ at the largest casino in the Paris suburbs. We evaluated pathological gambling and two addictive disorders (alcohol dependence and tobacco consumption) in the gamblers and their 690 parents (through the proband). Familial aggregation of pathological gambling was confirmed, with a risk of 3.3 for being a pathological gambler when at least one of the parents has problematic gambling. No familial co-aggregation of pathological gambling with alcohol or tobacco dependence was observed. Pathological gambling is found in excess in the parents of pathological casino gamblers, in accordance with previous aggregation studies devoted to other types of gambling, and with studies recruiting gamblers in different settings.  Copyright © American Academy of Addiction Psychiatry.

Ion beam studied of silicon oxynitride and silicon nitroxide thin layers

International Nuclear Information System (INIS)

Oude Elferink, J.B.

1989-01-01

In this the processes occurring during high temperature treatments of silicon oxynitride and silicon oxide layers are described. Oxynitride layers with various atomic oxygen to nitrogen concentration ration (O/N) are considered. The high energy ion beam techniques Rutherford backscattering spectroscopy, elastic recoil detection and nuclear reaction analysis have been used to study the layer structures. A detailed discussion of these ion beam techniques is given. Numerical methods used to obtain quantitative data on elemental compositions and depth profiles are described. The electrical compositions and depth profiles are described. The electrical properties of silicon nitride films are known to be influenced by the behaviour of hydrogen in the film during high temperature anneling. Investigations of the behaviour of hydrogen are presented. Oxidation of silicon (oxy)nitride films in O 2 /H 2 0/HCl and nitridation of silicon dioxide films in NH 3 are considered since oxynitrides are applied as an oxidation mask in the LOCOS (Local oxidation of silicon) process. The nitridation of silicon oxide layers in an ammonia ambient is considered. The initial stage and the dependence on the oxide thickness of nitrogen and hydrogen incorporation are discussed. Finally, oxidation of silicon oxynitride layers and of silicon oxide layers are compared. (author). 76 refs.; 48 figs.; 1 tab

Limitations and Constraints of Eddy-Current Loss Models for Interior Permanent-Magnet Motors with Fractional-Slot Concentrated Windings

Directory of Open Access Journals (Sweden)

Hui Zhang

2017-03-01

Full Text Available This paper analyzes and compares models for predicting average magnet losses in interior permanent-magnet motors with fractional-slot concentrated windings due to harmonics in the armature reaction (assuming sinusoidal phase currents. Particularly, loss models adopting different formulations and solutions to the Helmholtz equation to solve for the eddy currents are compared to a simpler model relying on an assumed eddy-current distribution. Boundaries in terms of magnet dimensions and angular frequency are identified (numerically and using an identified approximate analytical expression to aid the machine designer whether the more simple loss model is applicable or not. The assumption of a uniform flux-density variation (used in the loss models is also investigated for the case of V-shaped and straight interior permanent magnets. Finally, predicted volumetric loss densities are exemplified for combinations of slot and pole numbers common in automotive applications.

Nonlinear silicon photonics

Science.gov (United States)

Tsia, Kevin K.; Jalali, Bahram

2010-05-01

An intriguing optical property of silicon is that it exhibits a large third-order optical nonlinearity, with orders-ofmagnitude larger than that of silica glass in the telecommunication band. This allows efficient nonlinear optical interaction at relatively low power levels in a small footprint. Indeed, we have witnessed a stunning progress in harnessing the Raman and Kerr effects in silicon as the mechanisms for enabling chip-scale optical amplification, lasing, and wavelength conversion - functions that until recently were perceived to be beyond the reach of silicon. With all the continuous efforts developing novel techniques, nonlinear silicon photonics is expected to be able to reach even beyond the prior achievements. Instead of providing a comprehensive overview of this field, this manuscript highlights a number of new branches of nonlinear silicon photonics, which have not been fully recognized in the past. In particular, they are two-photon photovoltaic effect, mid-wave infrared (MWIR) silicon photonics, broadband Raman effects, inverse Raman scattering, and periodically-poled silicon (PePSi). These novel effects and techniques could create a new paradigm for silicon photonics and extend its utility beyond the traditionally anticipated applications.

Liquid phase epitaxial growth of silicon on porous silicon for photovoltaic applications

International Nuclear Information System (INIS)

Berger, S.; Quoizola, S.; Fave, A.; Kaminski, A.; Perichon, S.; Barbier, D.; Laugier, A.

2001-01-01

The aim of this experiment is to grow a thin silicon layer ( 2 atmosphere, and finally LPE silicon growth with different temperature profiles in order to obtain a silicon layer on the sacrificial porous silicon (p-Si). We observed a pyramidal growth on the surface of the (100) porous silicon but the coalescence was difficult to obtain. However, on a p-Si (111) oriented wafer, homogeneous layers were obtained. (orig.)

Comparison of scatter rejection and low-contrast performance of scan equalization digital radiography (SEDR), slot-scan digital radiography, and full-field digital radiography systems for chest phantom imaging

International Nuclear Information System (INIS)

Liu Xinming; Shaw, Chris C.; Lai, Chao-Jen; Wang Tianpeng

2011-01-01

Purpose: To investigate and compare the scatter rejection properties and low-contrast performance of the scan equalization digital radiography (SEDR) technique to the slot-scan and conventional full-field digital radiography techniques for chest imaging. Methods: A prototype SEDR system was designed and constructed with an a-Se flat-panel (FP) detector to improve image quality in heavily attenuating regions of an anthropomorphic chest phantom. Slot-scanning geometry was used to reject scattered radiation without attenuating primary x rays. The readout scheme of the FP was modified to erase accumulated scatter signals prior to image readout. A 24-segment beam width modulator was developed to regulate x-ray exposures regionally and compensate for the low x-ray flux in heavily attenuating regions. To measure the scatter-to-primary ratios (SPRs), a 2 mm thick lead plate with a 2-D array of aperture holes was used to measure the primary signals, which were then subtracted from those obtained without the lead plate to determine scatter components. A 2-D array of aluminum beads (3 mm in diameter) was used as the low-contrast objects to measure the contrast ratios (CRs) and contrast-to-noise ratios (CNRs) for evaluating the low-contrast performance in chest phantom images. A set of two images acquired with the same techniques were subtracted from each other to measure the noise levels. SPRs, CRs, and CNRs of the SEDR images were measured in four anatomical regions of chest phantom images and compared to those of slot-scan images and full-field images acquired with and without antiscatter grid. Results: The percentage reduction of SPR (percentage of SPRs reduced with scatter removal/rejection methods relative to that for nongrid full-field imaging) averaged over four anatomical regions was measured to be 80%, 83%, and 71% for SEDR, slot-scan, and full-field with grid, respectively. The average CR over four regions was found to improve over that for nongrid full

Comparison of scatter rejection and low-contrast performance of scan equalization digital radiography (SEDR), slot-scan digital radiography, and full-field digital radiography systems for chest phantom imaging

Energy Technology Data Exchange (ETDEWEB)

Liu Xinming; Shaw, Chris C.; Lai, Chao-Jen; Wang Tianpeng [Department of Imaging Physics, Digital Imaging Research Laboratory, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030-4009 (United States)

2011-01-15

Purpose: To investigate and compare the scatter rejection properties and low-contrast performance of the scan equalization digital radiography (SEDR) technique to the slot-scan and conventional full-field digital radiography techniques for chest imaging. Methods: A prototype SEDR system was designed and constructed with an a-Se flat-panel (FP) detector to improve image quality in heavily attenuating regions of an anthropomorphic chest phantom. Slot-scanning geometry was used to reject scattered radiation without attenuating primary x rays. The readout scheme of the FP was modified to erase accumulated scatter signals prior to image readout. A 24-segment beam width modulator was developed to regulate x-ray exposures regionally and compensate for the low x-ray flux in heavily attenuating regions. To measure the scatter-to-primary ratios (SPRs), a 2 mm thick lead plate with a 2-D array of aperture holes was used to measure the primary signals, which were then subtracted from those obtained without the lead plate to determine scatter components. A 2-D array of aluminum beads (3 mm in diameter) was used as the low-contrast objects to measure the contrast ratios (CRs) and contrast-to-noise ratios (CNRs) for evaluating the low-contrast performance in chest phantom images. A set of two images acquired with the same techniques were subtracted from each other to measure the noise levels. SPRs, CRs, and CNRs of the SEDR images were measured in four anatomical regions of chest phantom images and compared to those of slot-scan images and full-field images acquired with and without antiscatter grid. Results: The percentage reduction of SPR (percentage of SPRs reduced with scatter removal/rejection methods relative to that for nongrid full-field imaging) averaged over four anatomical regions was measured to be 80%, 83%, and 71% for SEDR, slot-scan, and full-field with grid, respectively. The average CR over four regions was found to improve over that for nongrid full

Nonlinear silicon photonics

Science.gov (United States)

Borghi, M.; Castellan, C.; Signorini, S.; Trenti, A.; Pavesi, L.

2017-09-01

Silicon photonics is a technology based on fabricating integrated optical circuits by using the same paradigms as the dominant electronics industry. After twenty years of fervid development, silicon photonics is entering the market with low cost, high performance and mass-manufacturable optical devices. Until now, most silicon photonic devices have been based on linear optical effects, despite the many phenomenologies associated with nonlinear optics in both bulk materials and integrated waveguides. Silicon and silicon-based materials have strong optical nonlinearities which are enhanced in integrated devices by the small cross-section of the high-index contrast silicon waveguides or photonic crystals. Here the photons are made to strongly interact with the medium where they propagate. This is the central argument of nonlinear silicon photonics. It is the aim of this review to describe the state-of-the-art in the field. Starting from the basic nonlinearities in a silicon waveguide or in optical resonator geometries, many phenomena and applications are described—including frequency generation, frequency conversion, frequency-comb generation, supercontinuum generation, soliton formation, temporal imaging and time lensing, Raman lasing, and comb spectroscopy. Emerging quantum photonics applications, such as entangled photon sources, heralded single-photon sources and integrated quantum photonic circuits are also addressed at the end of this review.

Transformational silicon electronics

KAUST Repository

Rojas, Jhonathan Prieto

2014-02-25

In today\\'s traditional electronics such as in computers or in mobile phones, billions of high-performance, ultra-low-power devices are neatly integrated in extremely compact areas on rigid and brittle but low-cost bulk monocrystalline silicon (100) wafers. Ninety percent of global electronics are made up of silicon. Therefore, we have developed a generic low-cost regenerative batch fabrication process to transform such wafers full of devices into thin (5 μm), mechanically flexible, optically semitransparent silicon fabric with devices, then recycling the remaining wafer to generate multiple silicon fabric with chips and devices, ensuring low-cost and optimal utilization of the whole substrate. We show monocrystalline, amorphous, and polycrystalline silicon and silicon dioxide fabric, all from low-cost bulk silicon (100) wafers with the semiconductor industry\\'s most advanced high-κ/metal gate stack based high-performance, ultra-low-power capacitors, field effect transistors, energy harvesters, and storage to emphasize the effectiveness and versatility of this process to transform traditional electronics into flexible and semitransparent ones for multipurpose applications. © 2014 American Chemical Society.

Silicon Microspheres Photonics

International Nuclear Information System (INIS)

Serpenguzel, A.

2008-01-01

Electrophotonic integrated circuits (EPICs), or alternatively, optoelectronic integrated circuit (OEICs) are the natural evolution of the microelectronic integrated circuit (IC) with the addition of photonic capabilities. Traditionally, the IC industry has been based on group IV silicon, whereas the photonics industry on group III-V semiconductors. However, silicon based photonic microdevices have been making strands in siliconizing photonics. Silicon microspheres with their high quality factor whispering gallery modes (WGMs), are ideal candidates for wavelength division multiplexing (WDM) applications in the standard near-infrared communication bands. In this work, we will discuss the possibility of using silicon microspheres for photonics applications in the near-infrared

Optical trapping via guided resonance modes in a Slot-Suzuki-phase photonic crystal lattice.

Science.gov (United States)

Ma, Jing; Martínez, Luis Javier; Povinelli, Michelle L

2012-03-12

A novel photonic crystal lattice is proposed for trapping a two-dimensional array of particles. The lattice is created by introducing a rectangular slot in each unit cell of the Suzuki-Phase lattice to enhance the light confinement of guided resonance modes. Large quality factors on the order of 10⁵ are predicted in the lattice. A significant decrease of the optical power required for optical trapping can be achieved compared to our previous design.

Analytical and hybrid methods in the theory of slot-hole coupling of electrodynamic volumes

CERN Document Server

Katrich, Victor A; Berdnik, Sergey L; Berdnik, Sergey L

2008-01-01

Narration of the text is both laconic and visually accessible, providing the reader with the possibility of rapid study and application of methods of computer analysis of electrodynamic problemsThe book is aimed at university professors, researchers and those specialists who are interested in theory and practical analysis of waveguide devices and systems using slot coupling elementsTopics included in the book are directly based on the original research results obtained by the authors and otherwise unknown earlier.

Production of technical silicon and silicon carbide from rice-husk

Directory of Open Access Journals (Sweden)

A. Z. Issagulov

2014-10-01

Full Text Available In the article there are studied physical and chemical properties of silicon-carbonic raw material – rice-husk, thermophysical characteristics of the process of rice-husk pyrolysis in nonreactive and oxidizing environment; structure and phase composition of products of the rice-husk pyrolysis in interval of temperatures 150 – 850 °С and high temperature pyrolysis in interval of temperatures 900 – 1 500 °С. There are defined the silicon-carbon production conditions, which meet the requirements applicable to charging materials at production of technical silicon and silicon carbide.

Photovoltaic characteristics of porous silicon /(n+ - p) silicon solar cells

International Nuclear Information System (INIS)

Dzhafarov, T.D.; Aslanov, S.S.; Ragimov, S.H.; Sadigov, M.S.; Nabiyeva, A.F.; Yuksel, Aydin S.

2012-01-01

Full text : The purpose of this work is to improve the photovoltaic parameters of the screen-printed silicon solar cells by formation the nano-porous silicon film on the frontal surface of the cell. The photovoltaic characteristics of two type silicon solar cells with and without porous silicon layer were measured and compared. A remarkable increment of short-circuit current density and the efficiency by 48 percent and 20 percent, respectively, have been achieved for PS/(n + - pSi) solar cell comparing to (n + - p)Si solar cell without PS layer

Performance improvement of silicon solar cells by nanoporous silicon coating

Directory of Open Access Journals (Sweden)

Dzhafarov T. D.

2012-04-01

Full Text Available In the present paper the method is shown to improve the photovoltaic parameters of screen-printed silicon solar cells by nanoporous silicon film formation on the frontal surface of the cell using the electrochemical etching. The possible mechanisms responsible for observed improvement of silicon solar cell performance are discussed.

Reprogramming hMSCs morphology with silicon/porous silicon geometric micro-patterns.

Science.gov (United States)

Ynsa, M D; Dang, Z Y; Manso-Silvan, M; Song, J; Azimi, S; Wu, J F; Liang, H D; Torres-Costa, V; Punzon-Quijorna, E; Breese, M B H; Garcia-Ruiz, J P

2014-04-01

Geometric micro-patterned surfaces of silicon combined with porous silicon (Si/PSi) have been manufactured to study the behaviour of human Mesenchymal Stem Cells (hMSCs). These micro-patterns consist of regular silicon hexagons surrounded by spaced columns of silicon equilateral triangles separated by PSi. The results show that, at an early culture stage, the hMSCs resemble quiescent cells on the central hexagons with centered nuclei and actin/β-catenin and a microtubules network denoting cell adhesion. After 2 days, hMSCs adapted their morphology and cytoskeleton proteins from cell-cell dominant interactions at the center of the hexagonal surface. This was followed by an intermediate zone with some external actin fibres/β-catenin interactions and an outer zone where the dominant interactions are cell-silicon. Cells move into silicon columns to divide, migrate and communicate. Furthermore, results show that Runx2 and vitamin D receptors, both specific transcription factors for skeleton-derived cells, are expressed in cells grown on micropatterned silicon under all observed circumstances. On the other hand, non-phenotypic alterations are under cell growth and migration on Si/PSi substrates. The former consideration strongly supports the use of micro-patterned silicon surfaces to address pending questions about the mechanisms of human bone biogenesis/pathogenesis and the study of bone scaffolds.

Comparison of static friction with self-ligating, modified slot design and conventional brackets

Directory of Open Access Journals (Sweden)

Raquel Morais Castro

2013-07-01

Full Text Available OBJECTIVE: To compare the static frictional forces generated at the bracket/wire interface of stainless steel brackets with different geometries and angulations, combined with orthodontic wires of different diameters. MATERIAL AND METHODS: The frictional forces were evaluated with three different types of metal brackets: a passive self-ligating (SmartClipTM, 3M/Unitek, Monrovia, USA, with a modified slot design (Mini Uni TwinTM, 3M/Unitek, Monrovia, USA and conventional (Kirium, Abzil, São José do Rio Preto, Brazil. The samples were mounted in a testing device with three different angulations and tested with 0.014" and 0.018" stainless steel wires (American Orthodontics, Sheboygan, USA. The static frictional force was measured using a universal testing machine (DL 500, EMIC®, São José dos Pinhais, Brazil with a crosshead speed of 1 mm/min. Statistical analysis was performed by two-way ANOVA followed by Bonferroni's post hoc test. RESULTS: There was a significant difference (p<0.05 in static friction when the three types of brackets were tested with the same wire size. The wire diameter influenced friction only when the brackets had a 10º angulation (p<0.05. The angulation influenced friction (p<0.05 when the brackets were associated with a 0.018" wire. CONCLUSION: Brackets with a modified slot design showed intermediate static frictional force values between the conventional and self-ligating brackets tested.

Study on structural properties of epitaxial silicon films on annealed double layer porous silicon

International Nuclear Information System (INIS)

Yue Zhihao; Shen Honglie; Cai Hong; Lv Hongjie; Liu Bin

2012-01-01

In this paper, epitaxial silicon films were grown on annealed double layer porous silicon by LPCVD. The evolvement of the double layer porous silicon before and after thermal annealing was investigated by scanning electron microscope. X-ray diffraction and Raman spectroscopy were used to investigate the structural properties of the epitaxial silicon thin films grown at different temperature and different pressure. The results show that the surface of the low-porosity layer becomes smooth and there are just few silicon-bridges connecting the porous layer and the substrate wafer. The qualities of the epitaxial silicon thin films become better along with increasing deposition temperature. All of the Raman peaks of silicon films with different deposition pressure are situated at 521 cm -1 under the deposition temperature of 1100 °C, and the Raman intensity of the silicon film deposited at 100 Pa is much closer to that of the monocrystalline silicon wafer. The epitaxial silicon films are all (4 0 0)-oriented and (4 0 0) peak of silicon film deposited at 100 Pa is more symmetric.

Release of low molecular weight silicones and platinum from silicone breast implants.

Science.gov (United States)

Lykissa, E D; Kala, S V; Hurley, J B; Lebovitz, R M

1997-12-01

We have conducted a series of studies addressing the chemical composition of silicone gels from breast implants as well as the diffusion of low molecular weight silicones (LM-silicones) and heavy metals from intact implants into various surrounding media, namely, lipid-rich medium (soy oil), aqueous tissue culture medium (modified Dulbecco's medium, DMEM), or an emulsion consisting of DMEM plus 10% soy oil. LM-silicones in both implants and surrounding media were detected and quantitated using gas chromatography (GC) coupled with atomic emission (GC-AED) as well as mass spectrometric (GC/MS) detectors, which can detect silicones in the nanogram range. Platinum, a catalyst used in the preparation of silicone gels, was detected and quantitated using inductive argon-coupled plasma/mass spectrometry (ICP-MS), which can detect platinum in the parts per trillion range. Our results indicate that GC-detectable low molecular weight silicones contribute approximately 1-2% to the total gel mass and consist predominantly of cyclic and linear poly-(dimethylsiloxanes) ranging from 3 to 20 siloxane [(CH3)2-Si-O] units (molecular weight 200-1500). Platinum can be detected in implant gels at levels of approximately 700 micrograms/kg by ICP-MS. The major component of implant gels appears to be high molecular weight silicone polymers (HM-silicones) too large to be detected by GC. However, these HM-silicones can be converted almost quantitatively (80% by mass) to LM-silicones by heating implant gels at 150-180 degrees C for several hours. We also studied the rates at which LM-silicones and platinum leak through the intact implant outer shell into the surrounding media under a variety of conditions. Leakage of silicones was greatest when the surrounding medium was lipid-rich, and up to 10 mg/day LM-silicones was observed to diffuse into a lipid-rich medium per 250 g of implant at 37 degrees C. This rate of leakage was maintained over a 7-day experimental period. Similarly, platinum was

Analysis of the ATLAS Cold Leg Top-Slot Break Experiment Using the MARS Code

Energy Technology Data Exchange (ETDEWEB)

Ha, T. W.; Jeong, J. J. [Pusan National University, Busan (Korea, Republic of)

2016-10-15

During a small-break loss of coolant accident (SBLOCA) or intermediate-break loss of coolant accident (IBLOCA) in a PWR, such as the APR1400, the steam volume in the reactor vessel upper plenum may continue to expand until the liquid phase in the horizontal intermediate legs is released, called loop seal clearing (LSC), due to the increase of the pressure in the upper plenum. A domestic standard problem (DSP) exercise using the ATLAS facility was promoted in order to transfer the database to domestic nuclear industries. For 4th DSP (DSP-04), the ATLAS cold leg top-slot break experiment was postulated. For the DSP-04, main concerns are to predict the LSC and LSR having a significantly effect on the behavior of the system under long term cooling. In this study, we simulated the ATLAS cold leg top-slot break experiment using the MARS code and the predicted LSC and LSR are compared to experimental results. The LTC-CL-04R was simulated using the MARS code. Most of the predicted results agree well with the experimental data. However, the timing of LSC and LSR is slightly different from each other and, thus, the behavior of the primary system is slightly different. The core heat up was not observed in the experiment and the calculation.

Light emitting structures porous silicon-silicon substrate

International Nuclear Information System (INIS)

Monastyrskii, L.S.; Olenych, I.B.; Panasjuk, M.R.; Savchyn, V.P.

1999-01-01

The research of spectroscopic properties of porous silicon has been done. Complex of photoluminescence, electroluminescence, cathodoluminescence, thermostimulated depolarisation current analyte methods have been applied to study of geterostructures and free layers of porous silicon. Light emitting processes had tendency to decrease. The character of decay for all kinds of luminescence were different

Gelcasting of SiC/Si for preparation of silicon nitride bonded silicon carbide

International Nuclear Information System (INIS)

Xie, Z.P.; Tsinghua University, Beijing,; Cheng, Y.B.; Lu, J.W.; Huang, Y.

2000-01-01

In the present paper, gelcasting of aqueous slurry with coarse silicon carbide(1mm) and fine silicon particles was investigated to fabricate silicon nitride bonded silicon carbide materials. Through the examination of influence of different polyelectrolytes on the Zeta potential and viscosity of silicon and silicon carbide suspensions, a stable SiC/Si suspension with 60 vol% solid loading could be prepared by using polyelectrolyte of D3005 and sodium alginate. Gelation of this suspension can complete in 10-30 min at 60-80 deg C after cast into mold. After demolded, the wet green body can be dried directly in furnace and the green strength will develop during drying. Complex shape parts with near net size were prepared by the process. Effects of the debindering process on nitridation and density of silicon nitride bonded silicon carbide were also examined. Copyright (2000) The Australian Ceramic Society

A Novel Dual-Band Circularly Polarized Rectangular Slot Antenna

Directory of Open Access Journals (Sweden)

Biao Li

2016-01-01

Full Text Available A coplanar waveguide fed dual-band circularly polarized rectangular slot antenna is presented. The proposed antenna consists of a rectangular metal frame acting as a ground and an S-shaped monopole as a radiator. The spatial distribution of the surface current density is employed to demonstrate that the circular polarization is generated by the S-shaped monopole which controls the path of the surface currents. An antenna prototype, having overall dimension 37 × 37 × 1 mm3, has been fabricated on FR4 substrate with dielectric constant 4.4. The proposed antenna achieves 10 dB return loss bandwidths and 3 dB axial ratio (AR in the frequency bands 2.39–2.81 GHz and 5.42–5.92 GHz, respectively. Both these characteristics are suitable for WLAN and WiMAX applications.

Silicon detectors

International Nuclear Information System (INIS)

Klanner, R.

1984-08-01

The status and recent progress of silicon detectors for high energy physics is reviewed. Emphasis is put on detectors with high spatial resolution and the use of silicon detectors in calorimeters. (orig.)

FTIR studies of swift silicon and oxygen ion irradiated porous silicon

International Nuclear Information System (INIS)

Bhave, Tejashree M.; Hullavarad, S.S.; Bhoraskar, S.V.; Hegde, S.G.; Kanjilal, D.

1999-01-01

Fourier Transform Infrared Spectroscopy has been used to study the bond restructuring in silicon and oxygen irradiated porous silicon. Boron doped p-type (1 1 1) porous silicon was irradiated with 10 MeV silicon and a 14 MeV oxygen ions at different doses ranging between 10 12 and 10 14 ions cm -2 . The yield of PL in porous silicon irradiated samples was observed to increase considerably while in oxygen irradiated samples it was seen to improve only by a small extent for lower doses whereas it decreased for higher doses. The results were interpreted in view of the relative intensities of the absorption peaks associated with O-Si-H and Si-H stretch bonds

Dual-band reflective polarization converter based on slotted wire resonators

Science.gov (United States)

Li, Fengxia; Zhang, Linbo; Zhou, Peiheng; Chen, Haiyan; Zhao, Rui; Zhou, Yang; Liang, Difei; Lu, Haipeng; Deng, Longjiang

2018-02-01

A dual-band and high-efficiency reflective linear polarization converter composed of a layer of slotted metal wires has been proposed. Both the simulated and experimental results indicate that the structure can convert a linearly polarized wave to its cross-polarized state for two distinct frequency bands under normal incidence: 9.8-15.1 and 19.2-25.7 GHz. This phenomenon is attributed to a resonance that corresponds to the "trapped mode" at 15.8 GHz. This mode is stable with structural parameters and incident angle at a relatively wide range, and thus becomes promising for dual-band (also multiband) devices design. By surface current distribution and electric field analysis, the operation mechanism has been illuminated, especially for the "trapped mode", identified by the equally but also oppositely directed currents in each unit cell.

Annealing temperature dependence of photoluminescent characteristics of silicon nanocrystals embedded in silicon-rich silicon nitride films grown by PECVD

International Nuclear Information System (INIS)

Chao, D.S.; Liang, J.H.

2013-01-01

Recently, light emission from silicon nanostructures has gained great interest due to its promising potential of realizing silicon-based optoelectronic applications. In this study, luminescent silicon nanocrystals (Si–NCs) were in situ synthesized in silicon-rich silicon nitride (SRSN) films grown by plasma-enhanced chemical vapor deposition (PECVD). SRSN films with various excess silicon contents were deposited by adjusting SiH 4 flow rate to 100 and 200 sccm and keeping NH 3 one at 40 sccm, and followed by furnace annealing (FA) treatments at 600, 850 and 1100 °C for 1 h. The effects of excess silicon content and post-annealing temperature on optical properties of Si–NCs were investigated by photoluminescence (PL) and Fourier transform infrared spectroscopy (FTIR). The origins of two groups of PL peaks found in this study can be attributed to defect-related interface states and quantum confinement effects (QCE). Defect-related interface states lead to the photon energy levels almost kept constant at about 3.4 eV, while QCE results in visible and tunable PL emission in the spectral range of yellow and blue light which depends on excess silicon content and post-annealing temperature. In addition, PL intensity was also demonstrated to be highly correlative to the excess silicon content and post-annealing temperature due to its corresponding effects on size, density, crystallinity, and surface passivation of Si–NCs. Considering the trade-off between surface passivation and structural properties of Si–NCs, an optimal post-annealing temperature of 600 °C was suggested to maximize the PL intensity of the SRSN films

Strategies for doped nanocrystalline silicon integration in silicon heterojunction solar cells

Czech Academy of Sciences Publication Activity Database

Seif, J.; Descoeudres, A.; Nogay, G.; Hänni, S.; de Nicolas, S.M.; Holm, N.; Geissbühler, J.; Hessler-Wyser, A.; Duchamp, M.; Dunin-Borkowski, R.E.; Ledinský, Martin; De Wolf, S.; Ballif, C.

2016-01-01

Roč. 6, č. 5 (2016), s. 1132-1140 ISSN 2156-3381 R&D Projects: GA MŠk LM2015087 Institutional support: RVO:68378271 Keywords : microcrystalline silicon * nanocrystalline silicon * silicon heterojunctions (SHJs) * solar cells Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.712, year: 2016

Periodically poled silicon

Science.gov (United States)

Hon, Nick K.; Tsia, Kevin K.; Solli, Daniel R.; Khurgin, Jacob B.; Jalali, Bahram

2010-02-01

Bulk centrosymmetric silicon lacks second-order optical nonlinearity χ(2) - a foundational component of nonlinear optics. Here, we propose a new class of photonic device which enables χ(2) as well as quasi-phase matching based on periodic stress fields in silicon - periodically-poled silicon (PePSi). This concept adds the periodic poling capability to silicon photonics, and allows the excellent crystal quality and advanced manufacturing capabilities of silicon to be harnessed for devices based on χ(2)) effects. The concept can also be simply achieved by having periodic arrangement of stressed thin films along a silicon waveguide. As an example of the utility, we present simulations showing that mid-wave infrared radiation can be efficiently generated through difference frequency generation from near-infrared with a conversion efficiency of 50% based on χ(2) values measurements for strained silicon reported in the literature [Jacobson et al. Nature 441, 199 (2006)]. The use of PePSi for frequency conversion can also be extended to terahertz generation. With integrated piezoelectric material, dynamically control of χ(2)nonlinearity in PePSi waveguide may also be achieved. The successful realization of PePSi based devices depends on the strength of the stress induced χ(2) in silicon. Presently, there exists a significant discrepancy in the literature between the theoretical and experimentally measured values. We present a simple theoretical model that produces result consistent with prior theoretical works and use this model to identify possible reasons for this discrepancy.

Efficiency Enhancement of Silicon Solar Cells by Porous Silicon Technology

Directory of Open Access Journals (Sweden)

Eugenijus SHATKOVSKIS

2012-09-01

Full Text Available Silicon solar cells produced by a usual technology in p-type, crystalline silicon wafer were investigated. The manufactured solar cells were of total thickness 450 mm, the junction depth was of 0.5 mm – 0.7 mm. Porous silicon technologies were adapted to enhance cell efficiency. The production of porous silicon layer was carried out in HF: ethanol = 1 : 2 volume ratio electrolytes, illuminating by 50 W halogen lamps at the time of processing. The etching current was computer-controlled in the limits of (6 ÷ 14 mA/cm2, etching time was set in the interval of (10 ÷ 20 s. The characteristics and performance of the solar cells samples was carried out illuminating by Xenon 5000 K lamp light. Current-voltage characteristic studies have shown that porous silicon structures produced affect the extent of dark and lighting parameters of the samples. Exactly it affects current-voltage characteristic and serial resistance of the cells. It has shown, the formation of porous silicon structure causes an increase in the electric power created of solar cell. Conversion efficiency increases also respectively to the initial efficiency of cell. Increase of solar cell maximum power in 15 or even more percent is found. The highest increase in power have been observed in the spectral range of Dl @ (450 ÷ 850 nm, where ~ 60 % of the A1.5 spectra solar energy is located. It has been demonstrated that porous silicon technology is effective tool to improve the silicon solar cells performance.DOI: http://dx.doi.org/10.5755/j01.ms.18.3.2428

Chiral silicon nanostructures

International Nuclear Information System (INIS)

Schubert, E.; Fahlteich, J.; Hoeche, Th.; Wagner, G.; Rauschenbach, B.

2006-01-01

Glancing angle ion beam assisted deposition is used for the growth of amorphous silicon nanospirals onto [0 0 1] silicon substrates in a temperature range from room temperature to 475 deg. C. The nanostructures are post-growth annealed in an argon atmosphere at various temperatures ranging from 400 deg. C to 800 deg. C. Recrystallization of silicon within the persisting nanospiral configuration is demonstrated for annealing temperatures above 800 deg. C. Transmission electron microscopy and Raman spectroscopy are used to characterize the silicon samples prior and after temperature treatment

The chemistry of silicon

CERN Document Server

Rochow, E G; Emeléus, H J; Nyholm, Ronald

1975-01-01

Pergamon Texts in Organic Chemistry, Volume 9: The Chemistry of Silicon presents information essential in understanding the chemical properties of silicon. The book first covers the fundamental aspects of silicon, such as its nuclear, physical, and chemical properties. The text also details the history of silicon, its occurrence and distribution, and applications. Next, the selection enumerates the compounds and complexes of silicon, along with organosilicon compounds. The text will be of great interest to chemists and chemical engineers. Other researchers working on research study involving s

Study on the graphene/silicon Schottky diodes by transferring graphene transparent electrodes on silicon

International Nuclear Information System (INIS)

Wang, Xiaojuan; Li, Dong; Zhang, Qichong; Zou, Liping; Wang, Fengli; Zhou, Jun; Zhang, Zengxing

2015-01-01

Graphene/silicon heterostructures present a Schottky characteristic and have potential applications for solar cells and photodetectors. Here, we fabricated graphene/silicon heterostructures by using chemical vapor deposition derived graphene and n-type silicon, and studied the electronic and optoelectronic properties through varying their interface and silicon resistivity. The results exhibit that the properties of the fabricated configurations can be effectively modulated. The graphene/silicon heterostructures with a Si (111) interface and high resistivity show a better photovoltaic behavior and should be applied for high-performance photodetectors. With the combined atomic force microscopy and theoretical analysis, the possible origination is discussed. The work here should be helpful on exploring high-performance graphene/silicon photoelectronics. - Highlights: • Different graphene/silicon heterostructures were fabricated. • Electronic and optoelectronic properties of the heterostructures were studied. • Graphene/silicon heterostructures were further explored for photodetectors.

Study on the graphene/silicon Schottky diodes by transferring graphene transparent electrodes on silicon

Energy Technology Data Exchange (ETDEWEB)

Wang, Xiaojuan [MOE Key Laboratory of Advanced Micro-structured Materials & Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Science and Engineering, Tongji University, Shanghai 200092 (China); School of Physics and Electronics, Henan University, Kaifeng 475004 (China); Li, Dong; Zhang, Qichong; Zou, Liping; Wang, Fengli [MOE Key Laboratory of Advanced Micro-structured Materials & Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Science and Engineering, Tongji University, Shanghai 200092 (China); Zhou, Jun, E-mail: zhoujunzhou@tongji.edu.cn [Center for Phononics and Thermal Energy Science, School of Physics Science and Engineering, Tongji University, Shanghai 200092 (China); Zhang, Zengxing, E-mail: zhangzx@tongji.edu.cn [MOE Key Laboratory of Advanced Micro-structured Materials & Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology, School of Physics Science and Engineering, Tongji University, Shanghai 200092 (China)

2015-10-01

Graphene/silicon heterostructures present a Schottky characteristic and have potential applications for solar cells and photodetectors. Here, we fabricated graphene/silicon heterostructures by using chemical vapor deposition derived graphene and n-type silicon, and studied the electronic and optoelectronic properties through varying their interface and silicon resistivity. The results exhibit that the properties of the fabricated configurations can be effectively modulated. The graphene/silicon heterostructures with a Si (111) interface and high resistivity show a better photovoltaic behavior and should be applied for high-performance photodetectors. With the combined atomic force microscopy and theoretical analysis, the possible origination is discussed. The work here should be helpful on exploring high-performance graphene/silicon photoelectronics. - Highlights: • Different graphene/silicon heterostructures were fabricated. • Electronic and optoelectronic properties of the heterostructures were studied. • Graphene/silicon heterostructures were further explored for photodetectors.

Slot-Die-Coated V2O5 as Hole Transport Layer for Flexible Organic Solar Cells and Optoelectronic Devices

DEFF Research Database (Denmark)

Beliatis, Michail; Helgesen, Martin; Garcia Valverde, Rafael

2016-01-01

Vanadium pentoxide has been proposed as a good alternative hole transport layer for improving device lifetime of organic photovoltaics. The article presents a study on the optimization of slot-die-coated vanadium oxide films produced with a roll coating machine with the aim of achieving scalable ...

Irradiation effects of swift heavy ions on gallium arsenide, silicon and silicon diodes

International Nuclear Information System (INIS)

Bhoraskar, V.N.

2001-01-01

The irradiation effects of high energy lithium, boron, oxygen and silicon ions on crystalline silicon, gallium arsenide, porous silicon and silicon diodes were investigated. The ion energy and fluence were varied over the ranges 30 to 100 MeV and 10 11 to 10 14 ions/cm 2 respectively. Semiconductor samples were characterized with the x-ray fluorescence, photoluminescence, thermally stimulated exo-electron emission and optical reflectivity techniques. The life-time of minority carriers in crystalline silicon was measured with a pulsed electron beam and the lithium depth distribution in GaAs was measured with the neutron depth profiling technique. The diodes were characterized through electrical measurements. The results of optical reflectivity, life-time of minority carriers and photoluminescence show that swift heavy ions induce defects in the surface region of crystalline silicon. In the ion-irradiated GaAs, migration of silicon, oxygen and lithium atoms from the buried region towards the surface was observed, with orders of magnitude enhancement in the diffusion coefficients. Enhancement in the photoluminescence intensity was observed in the GaAs and porous silicon samples that, were irradiated with silicon ions. The trade-off between the turn-off time and the voltage, drop in diodes irradiated with different swift heavy ions was also studied. (author)

Analytical and experimental evaluation of joining silicon carbide to silicon carbide and silicon nitride to silicon nitride for advanced heat engine applications Phase 2. Final report

Energy Technology Data Exchange (ETDEWEB)

Sundberg, G.J.; Vartabedian, A.M.; Wade, J.A.; White, C.S. [Norton Co., Northboro, MA (United States). Advanced Ceramics Div.

1994-10-01

The purpose of joining, Phase 2 was to develop joining technologies for HIP`ed Si{sub 3}N{sub 4} with 4wt% Y{sub 2}O{sub 3} (NCX-5101) and for a siliconized SiC (NT230) for various geometries including: butt joins, curved joins and shaft to disk joins. In addition, more extensive mechanical characterization of silicon nitride joins to enhance the predictive capabilities of the analytical/numerical models for structural components in advanced heat engines was provided. Mechanical evaluation were performed by: flexure strength at 22 C and 1,370 C, stress rupture at 1,370 C, high temperature creep, 22 C tensile testing and spin tests. While the silicon nitride joins were produced with sufficient integrity for many applications, the lower join strength would limit its use in the more severe structural applications. Thus, the silicon carbide join quality was deemed unsatisfactory to advance to more complex, curved geometries. The silicon carbide joining methods covered within this contract, although not entirely successful, have emphasized the need to focus future efforts upon ways to obtain a homogeneous, well sintered parent/join interface prior to siliconization. In conclusion, the improved definition of the silicon carbide joining problem obtained by efforts during this contract have provided avenues for future work that could successfully obtain heat engine quality joins.

Modeling and characterization of electret based vibration energy harvesters in slot-effect configuration

International Nuclear Information System (INIS)

Renaud, M; Altena, G; Elfrink, R; Goedbloed, M; De Nooijer, C; Van Schaijk, R

2015-01-01

The purpose of this article is to elaborate a model and the optimization guidelines for electret based harvesters with a specific electret/electrodes configuration, namely the slot-effect configuration. Slot-effect configured harvesters have been investigated experimentally by several research groups. A model describing their dynamic behavior has also been recently proposed in the literature. However, the simplifications used in the existing model can lead to inaccuracies and a refined analysis is elaborated in the present article. The model is compared with experimental measurements on MEMS fabricated devices with a corrugated electret. The electrodes dimensioning in the MEMS device are chosen so that the harvester behaves in a quasi-linear manner over its full range of displacement. This quasi-linearity simplifies greatly the device optimization. Indeed, the behavior of the developed electrostatic harvester is shown to be very comparable to that of piezoelectric harvesters, which are very well understood and documented. The influence of several design parameters on output power performance is investigated. As long as pull-in and breakdown voltage effects can be avoided, the electret surface potential should be maximized and the air gap minimized. We also investigate theoretically the influence of three types of electret on the generated power: planar, corrugated with partial charge coverage, and corrugated with full charge coverage. With the dimensions corresponding to our MEMS devices, the output power characteristics for the three types of electret are similar. However, it is shown that this is not always true. In some conditions, corrugated electrets with full charge coverage are detrimental for the generated power. (paper)

Hydrogen in amorphous silicon

International Nuclear Information System (INIS)

Peercy, P.S.

1980-01-01

The structural aspects of amorphous silicon and the role of hydrogen in this structure are reviewed with emphasis on ion implantation studies. In amorphous silicon produced by Si ion implantation of crystalline silicon, the material reconstructs into a metastable amorphous structure which has optical and electrical properties qualitatively similar to the corresponding properties in high-purity evaporated amorphous silicon. Hydrogen studies further indicate that these structures will accomodate less than or equal to 5 at.% hydrogen and this hydrogen is bonded predominantly in a monohydride (SiH 1 ) site. Larger hydrogen concentrations than this can be achieved under certain conditions, but the excess hydrogen may be attributed to defects and voids in the material. Similarly, glow discharge or sputter deposited amorphous silicon has more desirable electrical and optical properties when the material is prepared with low hydrogen concentration and monohydride bonding. Results of structural studies and hydrogen incorporation in amorphous silicon were discussed relative to the different models proposed for amorphous silicon

A convenient way of manufacturing silicon nanotubes on a silicon substrate

Energy Technology Data Exchange (ETDEWEB)

Zhang, Changchang; Cheng, Heming; Liu, Xiang, E-mail: liuxiang@ahut.edu.cn

2016-07-01

A convenient approach of preparing silicon nanotubes (SiNTs) on a silicon substrate is described in this work in detail. Firstly, a porous silicon (PSi) slice is prepared by a galvanic displacement reaction. Then it is put into aqueous solutions of 20% (w%) ammonium fluoride and 2.5 mM cobalt nitrate for a predetermined time. The cobalt ions are reduced and the resulted cobalt particles are deposited on the PSi slice. After the cobalt particles are removed with 5 M nitric acid a plenty of SiNTs come out and exhibit disorderly on the silicon substrate, which are illustrated by scanning electron microscopy (SEM). The compositions of the SiNTs are examined by energy-dispersive X-ray spectroscopy. Based on the SEM images, a suggested mechanism is put forward to explain the generation of the SiNTs on the PSi substrate. - Highlights: • A facile approach of preparing silicon nano tubes was invented. • The experimental results demonstrated the strong reducibility of Si-H{sub x} species. • It provided a new way of manufacturing silicon-contained hybrids.

Development of Radiation Hard Radiation Detectors, Differences between Czochralski Silicon and Float Zone Silicon

CERN Document Server

Tuominen, Eija

2012-01-01

The purpose of this work was to develop radiation hard silicon detectors. Radiation detectors made ofsilicon are cost effective and have excellent position resolution. Therefore, they are widely used fortrack finding and particle analysis in large high-energy physics experiments. Silicon detectors willalso be used in the CMS (Compact Muon Solenoid) experiment that is being built at the LHC (LargeHadron Collider) accelerator at CERN (European Organisation for Nuclear Research). This work wasdone in the CMS programme of Helsinki Institute of Physics (HIP).Exposure of the silicon material to particle radiation causes irreversible defects that deteriorate theperformance of the silicon detectors. In HIP CMS Programme, our approach was to improve theradiation hardness of the silicon material with increased oxygen concentration in silicon material. Westudied two different methods: diffusion oxygenation of Float Zone silicon and use of high resistivityCzochralski silicon.We processed, characterised, tested in a parti...

Resistive wall impedance of the LHC beam screen without slots calculated by boundary element method

CERN Document Server

Tsutsui, H

2002-01-01

In order to calculate the resistive wall impedance of the LHC beam screen without slots, the Boundary Element Method (BEM) is used. The result at 1 GHz is Re(ZL/L) = 6.689×10−3 Ω/m, Re(Zx/L) = 1.251 Ω/m2, Re(Zy/L) = 1.776 Ω/m2, andRe(2Z0,2 cos/kL) = −0.525 Ω/m2, assuming σ = 5.8 × 109 /Ωm.

Tunable inkjet-printed slotted waveguide antenna on a ferrite substrate

KAUST Repository

Nafe, Ahmed

2015-04-13

In this work an inkjet-printed frequency-tunable slotted waveguide antenna on a ferrite substrate is reported. Unlike the typical substrate integrated waveguide approach with via holes, a true 3D rectangular waveguide is realized by inkjet-printing of nano-particle based conductive ink on the broad faces as well as on sides of the substrate. The operating frequency of the antenna can be tuned by applying a variable static bias magnetic field that controls the permeability of the host ferrite substrate. The antenna operates about a center frequency of approximately 14 GHz with an instantaneous impedance bandwidth of 75 MHz. A fabricated prototype has demonstrated a tuning range of 10% (1.5 GHz) using an applied bias magnetic field of 3 kOe yielding it especially attractive for tunable and reconfigurable yet low cost microwave systems.

UHF coplanar-slot antenna for aircraft-to-satellite data communications

Science.gov (United States)

Myhre, R. W.

1979-01-01

The initiative for starting the Aircraft-to-Satellite Data Relay (ASDAR) Program came from a recognition that much of the world's weather originates in the data sparse area of the tropics which are primarily ocean. The ASDAR system consists of (1) a data acquisition and control unit to acquire, store and format these data; (2) a clock to time the data sampling and transmission periods; and (3) a transmitter and low-profile upper hemisphere coverage antenna to relay the formatted data via satellite to the National Weather Service ground stations, as shown schematically. The low-profile antenna is a conformal antenna based on the coplanar-slot approach. The antenna is circular polarized and has an on-axis gain of nearly 2.5 dB and a HPBW greater than 90 deg. The discussion covers antenna design, radiation characteristics, flight testing, and system performance.

Sensing performance of plasma-enhanced chemical vapor deposition SiC-SiO2-SiC horizontal slot waveguides

NARCIS (Netherlands)

Pandraud, G.; Margallo-Balbas, E.; Sarro, P.M.

2012-01-01

We have studied, for the first time, the sensing capabilities of plasma-enhanced chemical vapor deposition (PECVD) SiC-SiO2-SiC horizontal slot waveguides. Optical propagation losses were measured to be 23.9 dB?cm for the quasi-transverse magnetic mode. To assess the potential of this device as a

Methods To Determine the Silicone Oil Layer Thickness in Sprayed-On Siliconized Syringes.

Science.gov (United States)

Loosli, Viviane; Germershaus, Oliver; Steinberg, Henrik; Dreher, Sascha; Grauschopf, Ulla; Funke, Stefanie

2018-01-01

The silicone lubricant layer in prefilled syringes has been investigated with regards to siliconization process performance, prefilled syringe functionality, and drug product attributes, such as subvisible particle levels, in several studies in the past. However, adequate methods to characterize the silicone oil layer thickness and distribution are limited, and systematic evaluation is missing. In this study, white light interferometry was evaluated to close this gap in method understanding. White light interferometry demonstrated a good accuracy of 93-99% for MgF 2 coated, curved standards covering a thickness range of 115-473 nm. Thickness measurements for sprayed-on siliconized prefilled syringes with different representative silicone oil distribution patterns (homogeneous, pronounced siliconization at flange or needle side, respectively) showed high instrument (0.5%) and analyst precision (4.1%). Different white light interferometry instrument parameters (autofocus, protective shield, syringe barrel dimensions input, type of non-siliconized syringe used as base reference) had no significant impact on the measured average layer thickness. The obtained values from white light interferometry applying a fully developed method (12 radial lines, 50 mm measurement distance, 50 measurements points) were in agreement with orthogonal results from combined white and laser interferometry and 3D-laser scanning microscopy. The investigated syringe batches (lot A and B) exhibited comparable longitudinal silicone oil layer thicknesses ranging from 170-190 nm to 90-100 nm from flange to tip and homogeneously distributed silicone layers over the syringe barrel circumference (110- 135 nm). Empty break-loose (4-4.5 N) and gliding forces (2-2.5 N) were comparably low for both analyzed syringe lots. A silicone oil layer thickness of 100-200 nm was thus sufficient for adequate functionality in this particular study. Filling the syringe with a surrogate solution including short

CHARACTERIZATION OF THE ELECTROPHYSICAL PROPERTIES OF SILICON-SILICON DIOXIDE INTERFACE USING PROBE ELECTROMETRY METHODS

Directory of Open Access Journals (Sweden)

V. А. Pilipenko

2017-01-01

Full Text Available Introduction of submicron design standards into microelectronic industry and a decrease of the gate dielectric thickness raise the importance of the analysis of microinhomogeneities in the silicon-silicon dioxide system. However, there is very little to no information on practical implementation of probe electrometry methods, and particularly scanning Kelvin probe method, in the interoperational control of real semiconductor manufacturing process. The purpose of the study was the development of methods for nondestructive testing of semiconductor wafers based on the determination of electrophysical properties of the silicon-silicon dioxide interface and their spatial distribution over wafer’s surface using non-contact probe electrometry methods.Traditional C-V curve analysis and scanning Kelvin probe method were used to characterize silicon- silicon dioxide interface. The samples under testing were silicon wafers of KEF 4.5 and KDB 12 type (orientation <100>, diameter 100 mm.Probe electrometry results revealed uniform spatial distribution of wafer’s surface potential after its preliminary rapid thermal treatment. Silicon-silicon dioxide electric potential values were also higher after treatment than before it. This potential growth correlates with the drop in interface charge density. At the same time local changes in surface potential indicate changes in surface layer structure.Probe electrometry results qualitatively reflect changes of interface charge density in silicon-silicon dioxide structure during its technological treatment. Inhomogeneities of surface potential distribution reflect inhomogeneity of damaged layer thickness and can be used as a means for localization of interface treatment defects.

Silicon microphotonic waveguides

International Nuclear Information System (INIS)

Ta'eed, V.; Steel, M.J.; Grillet, C.; Eggleton, B.; Du, J.; Glasscock, J.; Savvides, N.

2004-01-01

Full text: Silicon microphotonic devices have been drawing increasing attention in the past few years. The high index-difference between silicon and its oxide (Δn = 2) suggests a potential for high-density integration of optical functions on to a photonic chip. Additionally, it has been shown that silicon exhibits strong Raman nonlinearity, a necessary property as light interaction can occur only by means of nonlinearities in the propagation medium. The small dimensions of silicon waveguides require the design of efficient tapers to couple light to them. We have used the beam propagation method (RSoft BeamPROP) to understand the principles and design of an inverse-taper mode-converter as implemented in several recent papers. We report on progress in the design and fabrication of silicon-based waveguides. Preliminary work has been conducted by patterning silicon-on-insulator (SOI) wafers using optical lithography and reactive ion etching. Thus far, only rib waveguides have been designed, as single-mode ridge-waveguides are beyond the capabilities of conventional optical lithography. We have recently moved to electron beam lithography as the higher resolutions permitted will provide the flexibility to begin fabricating sub-micron waveguides

Ceramic silicon-boron-carbon fibers from organic silicon-boron-polymers

Science.gov (United States)

Riccitiello, Salvatore R. (Inventor); Hsu, Ming-Ta S. (Inventor); Chen, Timothy S. (Inventor)

1993-01-01

Novel high strength ceramic fibers derived from boron, silicon, and carbon organic precursor polymers are discussed. The ceramic fibers are thermally stable up to and beyond 1200 C in air. The method of preparation of the boron-silicon-carbon fibers from a low oxygen content organosilicon boron precursor polymer of the general formula Si(R2)BR(sup 1) includes melt-spinning, crosslinking, and pyrolysis. Specifically, the crosslinked (or cured) precursor organic polymer fibers do not melt or deform during pyrolysis to form the silicon-boron-carbon ceramic fiber. These novel silicon-boron-carbon ceramic fibers are useful in high temperature applications because they retain tensile and other properties up to 1200 C, from 1200 to 1300 C, and in some cases higher than 1300 C.

Catastrophic degradation of the interface of epitaxial silicon carbide on silicon at high temperatures

Energy Technology Data Exchange (ETDEWEB)

Pradeepkumar, Aiswarya; Mishra, Neeraj; Kermany, Atieh Ranjbar; Iacopi, Francesca [Queensland Micro and Nanotechnology Centre and Environmental Futures Research Institute, Griffith University, Nathan QLD 4111 (Australia); Boeckl, John J. [Materials and Manufacturing Directorate, Air Force Research Laboratories, Wright-Patterson Air Force Base, Ohio 45433 (United States); Hellerstedt, Jack; Fuhrer, Michael S. [Monash Centre for Atomically Thin Materials, Monash University, Monash, VIC 3800 (Australia)

2016-07-04

Epitaxial cubic silicon carbide on silicon is of high potential technological relevance for the integration of a wide range of applications and materials with silicon technologies, such as micro electro mechanical systems, wide-bandgap electronics, and graphene. The hetero-epitaxial system engenders mechanical stresses at least up to a GPa, pressures making it extremely challenging to maintain the integrity of the silicon carbide/silicon interface. In this work, we investigate the stability of said interface and we find that high temperature annealing leads to a loss of integrity. High–resolution transmission electron microscopy analysis shows a morphologically degraded SiC/Si interface, while mechanical stress measurements indicate considerable relaxation of the interfacial stress. From an electrical point of view, the diode behaviour of the initial p-Si/n-SiC junction is catastrophically lost due to considerable inter-diffusion of atoms and charges across the interface upon annealing. Temperature dependent transport measurements confirm a severe electrical shorting of the epitaxial silicon carbide to the underlying substrate, indicating vast predominance of the silicon carriers in lateral transport above 25 K. This finding has crucial consequences on the integration of epitaxial silicon carbide on silicon and its potential applications.

Numerical investigation of variable inlet guide vanes with trailing-edge dual slots to decrease the aerodynamic load on centrifugal compressor impeller

Directory of Open Access Journals (Sweden)

Jianchi Xin

2016-03-01

Full Text Available In engineering practice, most centrifugal compressors use variable inlet guide vanes which can provide pre-whirl and control volume flow rates. As the impeller of a centrifugal compressor passes through the wakes created from the guide vanes, the aerodynamic parameters change significantly. The concept of adding dual slots at the trailing-edge of the guide vanes is proposed for reducing the aerodynamic load on the compressor impeller blades. In this article, the steady and unsteady performances of the new guide vanes are analysed under two compressor operating conditions (winter and design conditions. The results show that the average amplitude of the impeller passing frequency at the leading edge has a 13% decrease under the winter condition, especially at the middle and root parts. Moreover, the dual slots structure has no effect on the overall compressor performance.

Hybrid plasmonic waveguide-assisted Metal–Insulator–Metal ring resonator for refractive index sensing

Science.gov (United States)

Butt, M. A.; Khonina, S. N.; Kazanskiy, N. L.

2018-05-01

A highly sensitive refractive index sensor based on an integrated hybrid plasmonic waveguide (HPWG) and a Metal-Insulator-Metal (M-I-M) micro-ring resonator is presented. In our design, there are two slot-waveguide-based micro-rings that encircle a gold disc. The outer slot WG is formed by the combination of Silicon-Air-Gold ring and the inner slot-waveguide is formed by Gold ring-Air-Gold disc. The slot-waveguide rings provide an interaction length sufficient to accumulate a detectable wavelength shift. The transmission spectrum and electric field distribution of this sensor structure are simulated using Finite Element Method (FEM). The sensitivity of this micro-ring resonator is achieved at 800 nm/RIU which is about six times higher than that of the conventional Si ring with the same geometry. Our proposed sensor design has a potential to find further applications in biomedical science and nano-photonic circuits.

Using sound to unmask losses disguised as wins in multiline slot machines.

Science.gov (United States)

Dixon, Mike J; Collins, Karen; Harrigan, Kevin A; Graydon, Candice; Fugelsang, Jonathan A

2015-03-01

Losses disguised as wins (LDWs) are slot machine outcomes where participants bet on multiple lines and win back less than their wager. Despite losing money, the machine celebrates these outcomes with reinforcing sights and sounds. Here, we sought to show that psychophysically and psychologically, participants treat LDWs as wins, but that we could expose LDWs as losses by using negative sounds as feedback. 157 participants were allocated into one of three conditions: a standard sound condition where LDWs, despite being losses, are paired with winning sights and sounds; a silent condition, where LDWs are paired with silence; and a negative sound condition where LDWs and regular losses are both followed by a negative sound. After viewing a paytable, participants conducted 300 spins on a slot machine simulator while heart rate deceleration (HRD) and skin conductance responses (SCRs) were monitored. Participants were then shown 20 different spin outcomes including LDWs and asked whether they had won or lost on that outcome. Participants then estimated on how many spins (out of 300) they won more than they wagered. SCRs were similar for losses and LDWs (both smaller than actual wins). HRD, however, was steeper for both wins and LDWs, compared to losses. In the standard condition, a majority of participants (mis)categorized LDWs as wins, and significantly overestimated the number of times they actually won. In the negative sound condition, this pattern was reversed; most participants correctly categorized LDWs as losses, and they gave high-fidelity win estimates. We conclude that participants both think and physiologically react to LDWs as though they are wins, a miscategorization that misleads them to think that they are winning more often than they actually are. Sound can be used to effectively prevent this misconception and unmask the disguise of LDWs.

Cavités à fente à cristaux photoniques pour l'intégration hybride sur silicium

OpenAIRE

Hoang , Thi Hong Cam

2017-01-01

This Ph.D. work is a contribution to the modeling and the experimental study of slot photonic crystal cavities for hybrid on-silicon integration. Among the design works, we first have used plane the wave expansion and finite-difference time-domain methods to design a series of mechanically robust (non-free membrane) SOI slot photonic crystal heterostructure cavities with resonance wavelengths in the telecommunication range, i.e. from 1.3 µm – 1.6 µm, with Q-factors of around several tens of t...

Memory characteristics of silicon nitride with silicon nanocrystals as a charge trapping layer of nonvolatile memory devices

International Nuclear Information System (INIS)

Choi, Sangmoo; Yang, Hyundeok; Chang, Man; Baek, Sungkweon; Hwang, Hyunsang; Jeon, Sanghun; Kim, Juhyung; Kim, Chungwoo

2005-01-01

Silicon nitride with silicon nanocrystals formed by low-energy silicon plasma immersion ion implantation has been investigated as a charge trapping layer of a polycrystalline silicon-oxide-nitride-oxide-silicon-type nonvolatile memory device. Compared with the control sample without silicon nanocrystals, silicon nitride with silicon nanocrystals provides excellent memory characteristics, such as larger width of capacitance-voltage hysteresis, higher program/erase speed, and lower charge loss rate at elevated temperature. These improved memory characteristics are derived by incorporation of silicon nanocrystals into the charge trapping layer as additional accessible charge traps with a deeper effective trap energy level

The worst-case performance of the Cube per Order Index slotting strategy is infinitely bad – A technical note

NARCIS (Netherlands)

Schuur, Peter

2015-01-01

A well-known and frequently applied policy to assign stock keeping units (SKUs) to (dedicated) storage locations in a warehouse is the Cube per Order Index (COI) slotting strategy. Basically, COI stores an SKU based on how frequently it is picked per unit of stock space required. Fast movers are

Use of hydroxypropylmethylcellulose 2% for removing adherent silicone oil from silicone intraocular lenses

OpenAIRE

Wong , S Chien; Ramkissoon , Yashin D; Lopez , Mauricio; Page , Kristopher; Parkin , Ivan P; Sullivan , Paul M

2009-01-01

Abstract Background / aims: To investigate the effect of hydroxypropylmethylcellulose (HPMC) on the physical interaction (contact angle) between silicone oil and a silicone intraocular lens (IOL). Methods: In vitro experiments were performed, to determine the effect of HPMC (0.5%, 1% or 2%), with or without an additional simple mechanical manoeuvre, on the contact angle of silicone oil at the surface of both silicone and acrylic (control) IOLs. A balanced salt solu...

Single-Event Effects in Silicon and Silicon Carbide Power Devices

Science.gov (United States)

Lauenstein, Jean-Marie; Casey, Megan C.; LaBel, Kenneth A.; Topper, Alyson D.; Wilcox, Edward P.; Kim, Hak; Phan, Anthony M.

2014-01-01

NASA Electronics Parts and Packaging program-funded activities over the past year on single-event effects in silicon and silicon carbide power devices are presented, with focus on SiC device failure signatures.

Porous Silicon Nanowires

Science.gov (United States)

Qu, Yongquan; Zhou, Hailong; Duan, Xiangfeng

2011-01-01

In this minreview, we summarize recent progress in the synthesis, properties and applications of a new type of one-dimensional nanostructures — single crystalline porous silicon nanowires. The growth of porous silicon nanowires starting from both p- and n-type Si wafers with a variety of dopant concentrations can be achieved through either one-step or two-step reactions. The mechanistic studies indicate the dopant concentration of Si wafers, oxidizer concentration, etching time and temperature can affect the morphology of the as-etched silicon nanowires. The porous silicon nanowires are both optically and electronically active and have been explored for potential applications in diverse areas including photocatalysis, lithium ion battery, gas sensor and drug delivery. PMID:21869999

Formation of multiple levels of porous silicon for buried insulators and conductors in silicon device technologies

Science.gov (United States)

Blewer, Robert S.; Gullinger, Terry R.; Kelly, Michael J.; Tsao, Sylvia S.

1991-01-01

A method of forming a multiple level porous silicon substrate for semiconductor integrated circuits including anodizing non-porous silicon layers of a multi-layer silicon substrate to form multiple levels of porous silicon. At least one porous silicon layer is then oxidized to form an insulating layer and at least one other layer of porous silicon beneath the insulating layer is metallized to form a buried conductive layer. Preferably the insulating layer and conductive layer are separated by an anodization barrier formed of non-porous silicon. By etching through the anodization barrier and subsequently forming a metallized conductive layer, a fully or partially insulated buried conductor may be fabricated under single crystal silicon.

Silicon: electrochemistry and luminescence

NARCIS (Netherlands)

Kooij, Ernst Stefan

1997-01-01

The electrochemistry of crystalline and porous silicon and the luminescence from porous silicon has been studied. One chapter deals with a model for the anodic dissolution of silicon in HF solution. In following chapters both the electrochemistry and various ways of generating visible

Polycrystalline Silicon Gettered by Porous Silicon and Heavy Phosphorous Diffusion

Institute of Scientific and Technical Information of China (English)

LIU Zuming(刘祖明); Souleymane K Traore; ZHANG Zhongwen(张忠文); LUO Yi(罗毅)

2004-01-01

The biggest barrier for photovoltaic (PV) utilization is its high cost, so the key for scale PV utilization is to further decrease the cost of solar cells. One way to improve the efficiency, and therefore lower the cost, is to increase the minority carrier lifetime by controlling the material defects. The main defects in grain boundaries of polycrystalline silicon gettered by porous silicon and heavy phosphorous diffusion have been studied. The porous silicon was formed on the two surfaces of wafers by chemical etching. Phosphorous was then diffused into the wafers at high temperature (900℃). After the porous silicon and diffusion layers were removed, the minority carrier lifetime was measured by photo-conductor decay. The results show that the lifetime's minority carriers are increased greatly after such treatment.

Thermoelectric characteristics of Pt-silicide/silicon multi-layer structured p-type silicon

International Nuclear Information System (INIS)

Choi, Wonchul; Jun, Dongseok; Kim, Soojung; Shin, Mincheol; Jang, Moongyu

2015-01-01

Electric and thermoelectric properties of silicide/silicon multi-layer structured devices were investigated with the variation of silicide/silicon heterojunction numbers from 3 to 12 layers. For the fabrication of silicide/silicon multi-layered structure, platinum and silicon layers are repeatedly sputtered on the (100) silicon bulk substrate and rapid thermal annealing is carried out for the silicidation. The manufactured devices show ohmic current–voltage (I–V) characteristics. The Seebeck coefficient of bulk Si is evaluated as 195.8 ± 15.3 μV/K at 300 K, whereas the 12 layered silicide/silicon multi-layer structured device is evaluated as 201.8 ± 9.1 μV/K. As the temperature increases to 400 K, the Seebeck coefficient increases to 237.2 ± 4.7 μV/K and 277.0 ± 1.1 μV/K for bulk and 12 layered devices, respectively. The increase of Seebeck coefficient in multi-layered structure is mainly attributed to the electron filtering effect due to the Schottky barrier at Pt-silicide/silicon interface. At 400 K, the thermal conductivity is reduced by about half of magnitude compared to bulk in multi-layered device which shows the efficient suppression of phonon propagation by using Pt-silicide/silicon hetero-junctions. - Highlights: • Silicide/silicon multi-layer structured is proposed for thermoelectric devices. • Electric and thermoelectric properties with the number of layer are investigated. • An increase of Seebeck coefficient is mainly attributed the Schottky barrier. • Phonon propagation is suppressed with the existence of Schottky barrier. • Thermal conductivity is reduced due to the suppression of phonon propagation

Colloidal Photoluminescent Amorphous Porous Silicon, Methods Of Making Colloidal Photoluminescent Amorphous Porous Silicon, And Methods Of Using Colloidal Photoluminescent Amorphous Porous Silicon

KAUST Repository

Chaieb, Sahraoui

2015-04-09

Embodiments of the present disclosure provide for a colloidal photoluminescent amorphous porous silicon particle suspension, methods of making a colloidal photoluminescent amorphous porous silicon particle suspension, methods of using a colloidal photoluminescent amorphous porous silicon particle suspension, and the like.

Colloidal Photoluminescent Amorphous Porous Silicon, Methods Of Making Colloidal Photoluminescent Amorphous Porous Silicon, And Methods Of Using Colloidal Photoluminescent Amorphous Porous Silicon

KAUST Repository

Chaieb, Saharoui; Mughal, Asad Jahangir

2015-01-01

Embodiments of the present disclosure provide for a colloidal photoluminescent amorphous porous silicon particle suspension, methods of making a colloidal photoluminescent amorphous porous silicon particle suspension, methods of using a colloidal photoluminescent amorphous porous silicon particle suspension, and the like.

The effect of silicon crystallographic orientation on the formation of silicon nanoclusters during anodic electrochemical etching

International Nuclear Information System (INIS)

Timokhov, D. F.; Timokhov, F. P.

2009-01-01

Possible ways for increasing the photoluminescence quantum yield of porous silicon layers have been investigated. The effect of the anodization parameters on the photoluminescence properties for porous silicon layers formed on silicon substrates with different crystallographic orientations was studied. The average diameters for silicon nanoclusters are calculated from the photoluminescence spectra of porous silicon. The influence of the substrate crystallographic orientation on the photoluminescence quantum yield of porous silicon is revealed. A model explaining the effect of the substrate orientation on the photoluminescence properties for the porous silicon layers formed by anode electrochemical etching is proposed.

A GRASP algorithm for the container stowage slot planning problem

DEFF Research Database (Denmark)

Parreno, Francisco; Pacino, Dario; Alvarez-Valdes, Ramon

2016-01-01

in clusters along the vessel. For each of those clusters a specific position for each container must be found. Compared to previous studies, we have introduced two new features: the explicit handling of rolled out containers and the inclusion of separations rules for dangerous cargo. We present a novel......This work presents a generalization of the Slot Planning Problem which raises when the liner shipping industry needs to plan the placement of containers within a vessel (stowage planning). State-of-the-art stowage planning relies on a heuristic decomposition where containers are first distributed...... integer programming formulation and a Greedy Randomized Adaptive Search Procedure (GRASP) to solve the problem. The approach is able to find high-quality solution within 1 s. We also provide comparison with the state-of-the-art on an existing and a new set of benchmark instances. (C) 2016 Elsevier Ltd...

Harmonic Suppressed Slot Antennas Using Rectangular/Circular Defected Ground Structures

Directory of Open Access Journals (Sweden)

Mohammad Saeid Ghaffarian

2012-01-01

Full Text Available Two wide rectangle-shaped microstrip-fed 2.6-GHz slot antennas using defected ground structures (DGSs with a low design complexity are proposed to achieve wideband harmonic suppression. To accomplish this, two rectangular DGSs (RDGSs in the first antenna and two circular DGSs (CDGSs in the second one with various dimensions are etched into the ground plane, which could have a wideband-stop characteristic. Simulated and measured reflection coefficients indicate that the two proposed structures effectively suppress the second and third harmonics up to 23 dB between 3.5 and 10.5 GHz with a maximum ripple of 2.4 dB. In addition, the radiation patterns and peak gains of the antennas can be suppressed at least 17 dB and 7.1 dBi, respectively, at the third harmonic frequency of 7.86 GHz.

Joining elements of silicon carbide

International Nuclear Information System (INIS)

Olson, B.A.

1979-01-01

A method of joining together at least two silicon carbide elements (e.g.in forming a heat exchanger) is described, comprising subjecting to sufficiently non-oxidizing atmosphere and sufficiently high temperature, material placed in space between the elements. The material consists of silicon carbide particles, carbon and/or a precursor of carbon, and silicon, such that it forms a joint joining together at least two silicon carbide elements. At least one of the elements may contain silicon. (author)

Effect of bracket slot and archwire dimensions on anterior tooth movement during space closure in sliding mechanics: a 3-dimensional finite element study.

Science.gov (United States)

Tominaga, Jun-ya; Ozaki, Hiroya; Chiang, Pao-Chang; Sumi, Mayumi; Tanaka, Motohiro; Koga, Yoshiyuki; Bourauel, Christoph; Yoshida, Noriaki

2014-08-01

It has been found that controlled movement of the anterior teeth can be obtained by attaching a certain length of power arm onto an archwire in sliding mechanics. However, the impact of the archwire/bracket play on anterior tooth movement has not been clarified. The purpose of this study was to compare the effect of the power arm on anterior tooth movements with different dimensions of bracket slots and archwires. A 3-dimensional finite element method was used to simulate en-masse anterior tooth retraction in sliding mechanics. Displacements of the maxillary central incisor and the archwire deformation were calculated when applying retraction forces from different lengths of power arms. When a 0.017 × 0.022-in archwire was engaged into the 0.018-in slot bracket, bodily movement of the incisor was obtained with 9.1-mm length of the power arm. When a 0.022-in slot system was coupled with a 0.019 × 0.025-in archwire, bodily movement was observed with a power arm length of 11.6 mm. Archwire/bracket play has a remarkable impact on anterior tooth movement. An effective torque application to the anterior teeth becomes clinically difficult in sliding mechanics combined with power arms when the archwire/bracket play is large. Copyright © 2014 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

The effect of a magnetic field on heat transfer in a slotted channel

International Nuclear Information System (INIS)

Evtushenko, I.A.; Hua, T.Q.; Kirillov, I.R.; Reed, Claude B.; Sidorenkov, S.S.

1995-01-01

The results of numerical and experimental studies of liquid metal heat transfer in slotted channels in a transverse magnetic field are presented. Test results showed an improvement in heat transfer in a straight channel at low and moderate interaction parameter N. The Nusselt number at small N (around 120) was up to twofold higher than in turbulent flow without a magnetic field, the Peclet number being equal. This effect of heat transfer enhancement is caused by the generation and development of large-scale velocity fluctuations close to the heated wall area. Qualitative and quantitative correlations between heat transfer and velocity fluctuation characteristics are presented. (orig.)

Graphitized silicon carbide microbeams: wafer-level, self-aligned graphene on silicon wafers

International Nuclear Information System (INIS)

Cunning, Benjamin V; Ahmed, Mohsin; Mishra, Neeraj; Kermany, Atieh Ranjbar; Iacopi, Francesca; Wood, Barry

2014-01-01

Currently proven methods that are used to obtain devices with high-quality graphene on silicon wafers involve the transfer of graphene flakes from a growth substrate, resulting in fundamental limitations for large-scale device fabrication. Moreover, the complex three-dimensional structures of interest for microelectromechanical and nanoelectromechanical systems are hardly compatible with such transfer processes. Here, we introduce a methodology for obtaining thousands of microbeams, made of graphitized silicon carbide on silicon, through a site-selective and wafer-scale approach. A Ni-Cu alloy catalyst mediates a self-aligned graphitization on prepatterned SiC microstructures at a temperature that is compatible with silicon technologies. The graphene nanocoating leads to a dramatically enhanced electrical conductivity, which elevates this approach to an ideal method for the replacement of conductive metal films in silicon carbide-based MEMS and NEMS devices. (paper)

A multiband dual-standard MIMO antenna system based on monopoles (4G) and connected slots (5G) for future smart phones

KAUST Repository

Ikram, M.

2018-04-24

In this work, a 4G/5G multiple-input multiple-output (MIMO) antenna system is presented for smart phone applications. The 4G antenna operates from 1900 to 3212 MHz and 3517 to 3712 MHz with 1312 (69%) and 195 (5.5%) MHz measured bandwidths, respectively. The 5G antenna covers 25.7–30.50 GHz band with 4.8 GHz (18.7%) measured bandwidth. The 4G MIMO antenna system is based on 4-element wideband monopoles, while the 5G one is based on 2-element linear connected arrays (LCA). Four slots are etched to improve the isolation between the 4G MIMO antenna elements and then a 4 × 1 power divider/combiner is used to excite two of these slots to act as a LCA at mm-waves. The concept of dual function ground slots is very useful to implement 4G and 5G MIMO antenna systems on the single substrate. The proposed design is fabricated on RO4350B substrate with a height of 0.76 mm and dielectric constant of 3.5. The overall size of the substrate is 115 × 65 × 0.76 mm. The integrated wideband 4G/5G antenna system is a compact, low profile, and suitable for future smart phone applications. Isolation obtained was at least 15 dB and the envelope correlation coefficient (ECC) values did not exceed 0.16 between all elements.

Use of porous silicon to minimize oxidation induced stacking fault defects in silicon

International Nuclear Information System (INIS)

Shieh, S.Y.; Evans, J.W.

1992-01-01

This paper presents methods for minimizing stacking fault defects, generated during oxidation of silicon, include damaging the back of the wafer or depositing poly-silicon on the back. In either case a highly defective structure is created and this is capable of gettering either self-interstitials or impurities which promote nucleation of stacking fault defects. A novel method of minimizing these defects is to form a patch of porous silicon on the back of the wafer by electrochemical etching. Annealing under inert gas prior to oxidation may then result in the necessary gettering. Experiments were carried out in which wafers were subjected to this treatment. Subsequent to oxidation, the wafers were etched to remove oxide and reveal defects. The regions of the wafer adjacent to the porous silicon patch were defect-free, whereas remote regions had defects. Deep level transient spectroscopy has been used to examine the gettering capability of porous silicon, and the paper discusses the mechanism by which the porous silicon getters

Experimental Energy Consumption of Frame Slotted ALOHA and Distributed Queuing for Data Collection Scenarios

Directory of Open Access Journals (Sweden)

Pere Tuset-Peiro

2014-07-01

Full Text Available Data collection is a key scenario for the Internet of Things because it enables gathering sensor data from distributed nodes that use low-power and long-range wireless technologies to communicate in a single-hop approach. In this kind of scenario, the network is composed of one coordinator that covers a particular area and a large number of nodes, typically hundreds or thousands, that transmit data to the coordinator upon request. Considering this scenario, in this paper we experimentally validate the energy consumption of two Medium Access Control (MAC protocols, Frame Slotted ALOHA (FSA and Distributed Queuing (DQ. We model both protocols as a state machine and conduct experiments to measure the average energy consumption in each state and the average number of times that a node has to be in each state in order to transmit a data packet to the coordinator. The results show that FSA is more energy efficient than DQ if the number of nodes is known a priori because the number of slots per frame can be adjusted accordingly. However, in such scenarios the number of nodes cannot be easily anticipated, leading to additional packet collisions and a higher energy consumption due to retransmissions. Contrarily, DQ does not require to know the number of nodes in advance because it is able to efficiently construct an ad hoc network schedule for each collection round. This kind of a schedule ensures that there are no packet collisions during data transmission, thus leading to an energy consumption reduction above 10% compared to FSA.

Experimental energy consumption of Frame Slotted ALOHA and Distributed Queuing for data collection scenarios.

Science.gov (United States)

Tuset-Peiro, Pere; Vazquez-Gallego, Francisco; Alonso-Zarate, Jesus; Alonso, Luis; Vilajosana, Xavier

2014-07-24

Data collection is a key scenario for the Internet of Things because it enables gathering sensor data from distributed nodes that use low-power and long-range wireless technologies to communicate in a single-hop approach. In this kind of scenario, the network is composed of one coordinator that covers a particular area and a large number of nodes, typically hundreds or thousands, that transmit data to the coordinator upon request. Considering this scenario, in this paper we experimentally validate the energy consumption of two Medium Access Control (MAC) protocols, Frame Slotted ALOHA (FSA) and Distributed Queuing (DQ). We model both protocols as a state machine and conduct experiments to measure the average energy consumption in each state and the average number of times that a node has to be in each state in order to transmit a data packet to the coordinator. The results show that FSA is more energy efficient than DQ if the number of nodes is known a priori because the number of slots per frame can be adjusted accordingly. However, in such scenarios the number of nodes cannot be easily anticipated, leading to additional packet collisions and a higher energy consumption due to retransmissions. Contrarily, DQ does not require to know the number of nodes in advance because it is able to efficiently construct an ad hoc network schedule for each collection round. This kind of a schedule ensures that there are no packet collisions during data transmission, thus leading to an energy consumption reduction above 10% compared to FSA.

Indentation fatigue in silicon nitride, alumina and silicon carbide ...

Indian Academy of Sciences (India)

Repeated indentation fatigue (RIF) experiments conducted on the same spot of different structural ceramics viz. a hot pressed silicon nitride (HPSN), sintered alumina of two different grain sizes viz. 1 m and 25 m, and a sintered silicon carbide (SSiC) are reported. The RIF experiments were conducted using a Vicker's ...

Silicon web process development

Science.gov (United States)

Duncan, C. S.; Seidensticker, R. G.; Mchugh, J. P.; Skutch, M. E.; Driggers, J. M.; Hopkins, R. H.

1981-01-01

The silicon web process takes advantage of natural crystallographic stabilizing forces to grow long, thin single crystal ribbons directly from liquid silicon. The ribbon, or web, is formed by the solidification of a liquid film supported by surface tension between two silicon filaments, called dendrites, which border the edges of the growing strip. The ribbon can be propagated indefinitely by replenishing the liquid silicon as it is transformed to crystal. The dendritic web process has several advantages for achieving low cost, high efficiency solar cells. These advantages are discussed.

Characterization of silicon oxynitride films prepared by the simultaneous implantation of oxygen and nitrogen ions into silicon

International Nuclear Information System (INIS)

Hezel, R.; Streb, W.

1985-01-01

Silicon oxynitride films about 5 nm in thickness were prepared by simultaneously implanting 5 keV oxygen and nitrogen ions into silicon at room temperature up to saturation. These films with concentrations ranging from pure silicon oxide to silicon nitride were characterized using Auger electron spectroscopy, electron energy loss spectroscopy and depth-concentration profiling. The different behaviour of the silicon oxynitride films compared with those of silicon oxide and silicon nitride with regard to thermal stability and hardness against electron and argon ion irradiation is pointed out. (Auth.)

Silicon germanium mask for deep silicon etching

KAUST Repository

Serry, Mohamed

2014-07-29

Polycrystalline silicon germanium (SiGe) can offer excellent etch selectivity to silicon during cryogenic deep reactive ion etching in an SF.sub.6/O.sub.2 plasma. Etch selectivity of over 800:1 (Si:SiGe) may be achieved at etch temperatures from -80 degrees Celsius to -140 degrees Celsius. High aspect ratio structures with high resolution may be patterned into Si substrates using SiGe as a hard mask layer for construction of microelectromechanical systems (MEMS) devices and semiconductor devices.

Silicon germanium mask for deep silicon etching

KAUST Repository

Serry, Mohamed; Rubin, Andrew; Refaat, Mohamed; Sedky, Sherif; Abdo, Mohammad

2014-01-01

Polycrystalline silicon germanium (SiGe) can offer excellent etch selectivity to silicon during cryogenic deep reactive ion etching in an SF.sub.6/O.sub.2 plasma. Etch selectivity of over 800:1 (Si:SiGe) may be achieved at etch temperatures from -80 degrees Celsius to -140 degrees Celsius. High aspect ratio structures with high resolution may be patterned into Si substrates using SiGe as a hard mask layer for construction of microelectromechanical systems (MEMS) devices and semiconductor devices.

Evanescent field phase shifting in a silicon nitride waveguide using a coupled silicon slab

DEFF Research Database (Denmark)

Jensen, Asger Sellerup; Oxenløwe, Leif Katsuo; Green, William M. J.

2015-01-01

An approach for electrical modulation of low-loss silicon nitride waveguides is proposed, using a silicon nitride waveguide evanescently loaded with a thin silicon slab. The thermooptic phase-shift characteristics are investigated in a racetrack resonator configuration....

Selective formation of porous silicon

Science.gov (United States)

Fathauer, Robert W. (Inventor); Jones, Eric W. (Inventor)

1993-01-01

A pattern of porous silicon is produced in the surface of a silicon substrate by forming a pattern of crystal defects in said surface, preferably by applying an ion milling beam through openings in a photoresist layer to the surface, and then exposing said surface to a stain etchant, such as HF:HNO3:H2O. The defected crystal will preferentially etch to form a pattern of porous silicon. When the amorphous content of the porous silicon exceeds 70 percent, the porous silicon pattern emits visible light at room temperature.

Modulation Doping of Silicon using Aluminium-induced Acceptor States in Silicon Dioxide

OpenAIRE

K?nig, Dirk; Hiller, Daniel; Gutsch, Sebastian; Zacharias, Margit; Smith, Sean

2017-01-01

All electronic, optoelectronic or photovoltaic applications of silicon depend on controlling majority charge carriers via doping with impurity atoms. Nanoscale silicon is omnipresent in fundamental research (quantum dots, nanowires) but also approached in future technology nodes of the microelectronics industry. In general, silicon nanovolumes, irrespective of their intended purpose, suffer from effects that impede conventional doping due to fundamental physical principles such as out-diffusi...

Proceedings of the 20th International Conference on Defects in Semiconductors Held in Berkeley, CA, USA, 26-30 July 1999

Science.gov (United States)

1999-07-30

National Science Foundation through the GOALI Program, under grant number ECS-9705134. References [1] T. Ogino, M. Aoki, Jap. J. Appl. Phys. 19 (1980... pulled from molten silicon through a graphite slot for solar cell production in economical way [8]. It was observed that EFG silicon contains high...samples the closest resem- blance to our observations is found in the Au-Hj config- uration where the --/- gold acceptor level is pulled down in the

Design optimization for permanent magnet machine with efficient slot per pole ratio

Science.gov (United States)

Potnuru, Upendra Kumar; Rao, P. Mallikarjuna

2018-04-01

This paper presents a methodology for the enhancement of a Brush Less Direct Current motor (BLDC) with 6Poles and 8slots. In particular; it is focused on amulti-objective optimization using a Genetic Algorithmand Grey Wolf Optimization developed in MATLAB. The optimization aims to maximize the maximum output power value and minimize the total losses of a motor. This paper presents an application of the MATLAB optimization algorithms to brushless DC (BLDC) motor design, with 7 design parameters chosen to be free. The optimal design parameters of the motor derived by GA are compared with those obtained by Grey Wolf Optimization technique. A comparative report on the specified enhancement approaches appearsthat Grey Wolf Optimization technique has a better convergence.

Optical property of silicon quantum dots embedded in silicon nitride by thermal annealing

Energy Technology Data Exchange (ETDEWEB)

Kim, Baek Hyun, E-mail: bhkim@andrew.cmu.ed [Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, United Sates (United States); Davis, Robert F. [Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, United Sates (United States); Park, Seong-Ju [Nanophotonic Semiconductors Laboratory, Department of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, 500-712 (Korea, Republic of)

2010-01-01

We present the effects on the thermal annealing of silicon quantum dots (Si QDs) embedded in silicon nitride. The improved photoluminescence (PL) intensities and the red-shifted PL spectra were obtained with annealing treatment in the range of 700 to 1000 {sup o}C. The shifts of PL spectra were attributed to the increase in the size of Si QDs. The improvement of the PL intensities was also attributed to the reduction of point defects at Si QD/silicon nitride interface and in the silicon nitride due to hydrogen passivation effects.

Silicon photonics fundamentals and devices

CERN Document Server

Deen, M Jamal

2012-01-01

The creation of affordable high speed optical communications using standard semiconductor manufacturing technology is a principal aim of silicon photonics research. This would involve replacing copper connections with optical fibres or waveguides, and electrons with photons. With applications such as telecommunications and information processing, light detection, spectroscopy, holography and robotics, silicon photonics has the potential to revolutionise electronic-only systems. Providing an overview of the physics, technology and device operation of photonic devices using exclusively silicon and related alloys, the book includes: * Basic Properties of Silicon * Quantum Wells, Wires, Dots and Superlattices * Absorption Processes in Semiconductors * Light Emitters in Silicon * Photodetectors , Photodiodes and Phototransistors * Raman Lasers including Raman Scattering * Guided Lightwaves * Planar Waveguide Devices * Fabrication Techniques and Material Systems Silicon Photonics: Fundamentals and Devices outlines ...

Twenty-fold plasmon-induced enhancement of radiative emission rate in silicon nanocrystals embedded in silicon dioxide

International Nuclear Information System (INIS)

Gardelis, S; Gianneta, V.; Nassiopoulou, A.G

2016-01-01

We report on a 20-fold enhancement of the integrated photoluminescence (PL) emission of silicon nanocrystals, embedded in a matrix of silicon dioxide, induced by excited surface plasmons from silver nanoparticles, which are located in the vicinity of the silicon nanocrystals and separated from them by a silicon dioxide layer of a few nanometers. The electric field enhancement provided by the excited surface plasmons increases the absorption cross section and the emission rate of the nearby silicon nanocrystals, resulting in the observed enhancement of the photoluminescence, mainly attributed to a 20-fold enhancement in the emission rate of the silicon nanocrystals. The observed remarkable improvement of the PL emission makes silicon nanocrystals very useful material for photonic, sensor and solar cell applications.

Ambient fabrication of flexible and large-area organic light-emitting devices using slot-die coating

DEFF Research Database (Denmark)

Sandstrom, Andreas; Dam, Henrik Friis; Krebs, Frederik C

2012-01-01

available in smartphones, but the promise of a continuous ambient fabrication has unfortunately not materialized yet, as organic light-emitting diodes invariably depend on the use of one or more time-and energy-consuming process steps under vacuum. Here we report an all-solution-based fabrication...... of an alternative emissive device, a light-emitting electrochemical cell, using a slot-die roll-coating apparatus. The fabricated flexible sheets exhibit bidirectional and uniform light emission, and feature a fault-tolerant >1-mu m-thick active material that is doped in situ during operation. It is notable...

Model Testing of the Wave Energy Converter Seawave Slot-Cone Generator

DEFF Research Database (Denmark)

Kofoed, Jens Peter

This report presents the results of a preliminary experimental study of the wave energy convert (WEC) Seawave Slot-Cone Generator (SSG). SSG is a WEC utilizing wave overtopping in multiple reservoirs. In the present SSG setup three reservoirs has been used. Model tests have been performed using...... a scale model (length scale 1:15) of a SSG device to be installed on the west coast of the island Kvitsøy near Stavanger, Norway. The tests were carried out at Dept. of Civil Engineering, Aalborg University (AAU) in the 3D deep water wave tank. The model has been subjected to regular and irregular waves...... corresponding to typical conditions off shore from the intended installation site. The overtopping rates for the individual reservoirs have been measured and the potential energy in the overtopping water has been calculated....

A Novel CPW BandPass Filter Integrating Periodic Rectangular Slot Cells

Directory of Open Access Journals (Sweden)

Fouad Aytouna

2015-12-01

Full Text Available In this paper, we introduce the design and the achievement of a Bandpass filter structure based on the use of rectangular slot cell. The originality of this work is to achieve a coplanar filter easy to integrate with microwave planar circuits and having a wide frequency bandwidth. The proposed bandpass filter is a low cost and compact planar filter structure. The final circuit is simulated by using two electromagnetic solvers, ADS and HFSS. The validation into simulation is based on using optimization methods integrated into the both solvers. Simulations have taken into account a high meshing density to cover the whole circuit. The fabricated bandpass filter has an area of 35X31mm2 and having a good insertion loss around -0.75dB in the bandwidth. The comparison between simulation and measurement results presents a good agreement.

Direct Production of Silicones From Sand

Energy Technology Data Exchange (ETDEWEB)

Larry N. Lewis; F.J. Schattenmann: J.P. Lemmon

2001-09-30

Silicon, in the form of silica and silicates, is the second most abundant element in the earth's crust. However the synthesis of silicones (scheme 1) and almost all organosilicon chemistry is only accessible through elemental silicon. Silicon dioxide (sand or quartz) is converted to chemical-grade elemental silicon in an energy intensive reduction process, a result of the exceptional thermodynamic stability of silica. Then, the silicon is reacted with methyl chloride to give a mixture of methylchlorosilanes catalyzed by cooper containing a variety of tract metals such as tin, zinc etc. The so-called direct process was first discovered at GE in 1940. The methylchlorosilanes are distilled to purify and separate the major reaction components, the most important of which is dimethyldichlorosilane. Polymerization of dimethyldichlorosilane by controlled hydrolysis results in the formation of silicone polymers. Worldwide, the silicones industry produces about 1.3 billion pounds of the basic silicon polymer, polydimethylsiloxane.

Flexible Thermoelectric Generators on Silicon Fabric

KAUST Repository

Sevilla, Galo T.

2012-11-01

In this work, the development of a Thermoelectric Generator on Flexible Silicon Fabric is explored to extend silicon electronics for flexible platforms. Low cost, easily deployable plastic based flexible electronics are of great interest for smart textile, wearable electronics and many other exciting applications. However, low thermal budget processing and fundamentally limited electron mobility hinders its potential to be competitive with well established and highly developed silicon technology. The use of silicon in flexible electronics involve expensive and abrasive materials and processes. In this work, high performance flexible thermoelectric energy harvesters are demonstrated from low cost bulk silicon (100) wafers. The fabrication of the micro- harvesters was done using existing silicon processes on silicon (100) and then peeled them off from the original substrate leaving it for reuse. Peeled off silicon has 3.6% thickness of bulk silicon reducing the thermal loss significantly and generating nearly 30% more output power than unpeeled harvesters. The demonstrated generic batch processing shows a pragmatic way of peeling off a whole silicon circuitry after conventional fabrication on bulk silicon wafers for extremely deformable high performance integrated electronics. In summary, by using a novel, low cost process, this work has successfully integrated existing and highly developed fabrication techniques to introduce a flexible energy harvester for sustainable applications.

Subwavelength silicon photonics

International Nuclear Information System (INIS)

Cheben, P.; Bock, P.J.; Schmid, J.H.; Lapointe, J.; Janz, S.; Xu, D.-X.; Densmore, A.; Delage, A.; Lamontagne, B.; Florjanczyk, M.; Ma, R.

2011-01-01

With the goal of developing photonic components that are compatible with silicon microelectronic integrated circuits, silicon photonics has been the subject of intense research activity. Silicon is an excellent material for confining and manipulating light at the submicrometer scale. Silicon optoelectronic integrated devices have the potential to be miniaturized and mass-produced at affordable cost for many applications, including telecommunications, optical interconnects, medical screening, and biological and chemical sensing. We review recent advances in silicon photonics research at the National Research Council Canada. A new type of optical waveguide is presented, exploiting subwavelength grating (SWG) effect. We demonstrate subwavelength grating waveguides made of silicon, including practical components operating at telecom wavelengths: input couplers, waveguide crossings and spectrometer chips. SWG technique avoids loss and wavelength resonances due to diffraction effects and allows for single-mode operation with direct control of the mode confinement by changing the refractive index of a waveguide core over a range as broad as 1.6 - 3.5 simply by lithographic patterning. The light can be launched to these waveguides with a coupling loss as small as 0.5 dB and with minimal wavelength dependence, using coupling structures similar to that shown in Fig. 1. The subwavelength grating waveguides can cross each other with minimal loss and negligible crosstalk which allows massive photonic circuit connectivity to overcome the limits of electrical interconnects. These results suggest that the SWG waveguides could become key elements for future integrated photonic circuits. (authors)

Silicon photonic integration in telecommunications

Directory of Open Access Journals (Sweden)

Christopher Richard Doerr

2015-08-01

Full Text Available Silicon photonics is the guiding of light in a planar arrangement of silicon-based materials to perform various functions. We focus here on the use of silicon photonics to create transmitters and receivers for fiber-optic telecommunications. As the need to squeeze more transmission into a given bandwidth, a given footprint, and a given cost increases, silicon photonics makes more and more economic sense.

Silicon microphones - a Danish perspective

DEFF Research Database (Denmark)

Bouwstra, Siebe; Storgaard-Larsen, Torben; Scheeper, Patrick

1998-01-01

Two application areas of microphones are discussed, those for precision measurement and those for hearing instruments. Silicon microphones are under investigation for both areas, and Danish industry plays a key role in both. The opportunities of silicon, as well as the challenges and expectations......, are discussed. For precision measurement the challenge for silicon is large, while for hearing instruments silicon seems to be very promising....

Integrated silicon optoelectronics

CERN Document Server

Zimmermann, Horst

2000-01-01

'Integrated Silicon Optoelectronics'assembles optoelectronics and microelectronics The book concentrates on silicon as the major basis of modern semiconductor devices and circuits Starting from the basics of optical emission and absorption and from the device physics of photodetectors, the aspects of the integration of photodetectors in modern bipolar, CMOS, and BiCMOS technologies are discussed Detailed descriptions of fabrication technologies and applications of optoelectronic integrated circuits are included The book, furthermore, contains a review of the state of research on eagerly expected silicon light emitters In order to cover the topic of the book comprehensively, integrated waveguides, gratings, and optoelectronic power devices are included in addition Numerous elaborate illustrations promote an easy comprehension 'Integrated Silicon Optoelectronics'will be of value to engineers, physicists, and scientists in industry and at universities The book is also recommendable for graduate students speciali...

High-performance permanent magnet brushless motors with balanced concentrated windings and similar slot and pole numbers

International Nuclear Information System (INIS)

Stumberger, Bojan; Stumberger, Gorazd; Hadziselimovic, Miralem; Hamler, Anton; Trlep, Mladen; Gorican, Viktor; Jesenik, Marko

2006-01-01

The paper presents a comparison between the performances of exterior-rotor permanent magnet brushless motors with distributed windings and the performances of exterior-rotor permanent magnet brushless motors with concentrated windings. Finite element method analysis is employed to determine the performance of each motor. It is shown that motors with concentrated windings and similar slot and pole numbers exhibit similar or better performances than motors with distributed windings for brushless AC (BLAC) operation mode and brushless DC (BLDC) operation mode as well

An Experimental and Numerical Investigation of Endwall Aerodynamics and Heat Transfer in a Gas Turbine Nozzle Guide Vane with Slot Film Cooling

Science.gov (United States)

Alqefl, Mahmood Hasan

In many regions of the high-pressure gas turbine, film cooling flows are used to protect the turbine components from the combustor exit hot gases. Endwalls are challenging to cool because of the complex system of secondary flows that disturb surface film coolant coverage. The secondary flow vortices wash the film coolant from the surface into the mainstream significantly decreasing cooling effectiveness. In addition to being effected by secondary flow structures, film cooling flow can also affect these structures by virtue of their momentum exchange. In addition, many studies in the literature have shown that endwall contouring affects the strength of passage secondary flows. Therefore, to develop better endwall cooling schemes, a good understanding of passage aerodynamics and heat transfer as affected by interactions of film cooling flows with secondary flows is required. This experimental and computational study presents results from a linear, stationary, two-passage cascade representing the first stage nozzle guide vane of a high-pressure gas turbine with an axisymmetrically contoured endwall. The sources of film cooling flows are upstream combustor liner coolant and endwall slot film coolant injected immediately upstream of the cascade passage inlet. The operating conditions simulate combustor exit flow features, with a high Reynolds number of 390,000 and approach flow turbulence intensity of 11% with an integral length scale of 21% of the chord length. Measurements are performed with varying slot film cooling mass flow to mainstream flow rate ratios (MFR). Aerodynamic effects are documented with five-hole probe measurements at the exit plane. Heat transfer is documented through recovery temperature measurements with a thermocouple. General secondary flow features are observed. Total pressure loss measurements show that varying the slot film cooling MFR has some effects on passage loss. Velocity vectors and vorticity distributions show a very thin, yet intense

Selective dry etching of silicon containing anti-reflective coating

Science.gov (United States)

Sridhar, Shyam; Nolan, Andrew; Wang, Li; Karakas, Erdinc; Voronin, Sergey; Biolsi, Peter; Ranjan, Alok

2018-03-01

Multi-layer patterning schemes involve the use of Silicon containing Anti-Reflective Coating (SiARC) films for their anti-reflective properties. Patterning transfer completion requires complete and selective removal of SiARC which is very difficult due to its high silicon content (>40%). Typically, SiARC removal is accomplished through a non-selective etch during the pattern transfer process using fluorine containing plasmas, or an ex-situ wet etch process using hydrofluoric acid is employed to remove the residual SiARC, post pattern transfer. Using a non-selective etch may result in profile distortion or wiggling, due to distortion of the underlying organic layer. The drawbacks of using wet etch process for SiARC removal are increased overall processing time and the need for additional equipment. Many applications may involve patterning of active structures in a poly-Si layer with an underlying oxide stopping layer. In such applications, SiARC removal selective to oxide using a wet process may prove futile. Removing SiARC selectively to SiO2 using a dry etch process is also challenging, due to similarity in the nature of chemical bonds (Si - O) in the two materials. In this work, we present highly selective etching of SiARC, in a plasma driven by a surface wave radial line slot antenna. The first step in the process involves an in-situ modification of the SiARC layer in O2 plasma followed by selective etching in a NF3/H2 plasma. Surface treatment in O2 plasma resulted in enhanced etching of the SiARC layer. For the right processing conditions, in-situ NF3/H2 dry etch process demonstrated selectivity values greater than 15:1 with respect to SiO2. The etching chemistry, however, was sensitive to NF3:H2 gas ratio. For dilute NF3 in H2, no SiARC etching was observed. Presumably, this is due to the deposition of ammonium fluorosilicate layer that occurs for dilute NF3/H2 plasmas. Additionally, challenges involved in selective SiARC removal (selective to SiO2, organic

Process for making silicon

Science.gov (United States)

Levin, Harry (Inventor)

1987-01-01

A reactor apparatus (10) adapted for continuously producing molten, solar grade purity elemental silicon by thermal reaction of a suitable precursor gas, such as silane (SiH.sub.4), is disclosed. The reactor apparatus (10) includes an elongated reactor body (32) having graphite or carbon walls which are heated to a temperature exceeding the melting temperature of silicon. The precursor gas enters the reactor body (32) through an efficiently cooled inlet tube assembly (22) and a relatively thin carbon or graphite septum (44). The septum (44), being in contact on one side with the cooled inlet (22) and the heated interior of the reactor (32) on the other side, provides a sharp temperature gradient for the precursor gas entering the reactor (32) and renders the operation of the inlet tube assembly (22) substantially free of clogging. The precursor gas flows in the reactor (32) in a substantially smooth, substantially axial manner. Liquid silicon formed in the initial stages of the thermal reaction reacts with the graphite or carbon walls to provide a silicon carbide coating on the walls. The silicon carbide coated reactor is highly adapted for prolonged use for production of highly pure solar grade silicon. Liquid silicon (20) produced in the reactor apparatus (10) may be used directly in a Czochralski or other crystal shaping equipment.

Silicon etch process

International Nuclear Information System (INIS)

Day, D.J.; White, J.C.

1984-01-01

A silicon etch process wherein an area of silicon crystal surface is passivated by radiation damage and non-planar structure produced by subsequent anisotropic etching. The surface may be passivated by exposure to an energetic particle flux - for example an ion beam from an arsenic, boron, phosphorus, silicon or hydrogen source, or an electron beam. Radiation damage may be used for pattern definition and/or as an etch stop. Ethylenediamine pyrocatechol or aqueous potassium hydroxide anisotropic etchants may be used. The radiation damage may be removed after etching by thermal annealing. (author)

Porous silicon gettering

Energy Technology Data Exchange (ETDEWEB)

Tsuo, Y.S.; Menna, P.; Pitts, J.R. [National Renewable Energy Lab., Golden, CO (United States)] [and others

1996-05-01

The authors have studied a novel extrinsic gettering method that uses the large surface areas produced by a porous-silicon etch as gettering sites. The annealing step of the gettering used a high-flux solar furnace. They found that a high density of photons during annealing enhanced the impurity diffusion to the gettering sites. The authors used metallurgical-grade Si (MG-Si) prepared by directional solidification casing as the starting material. They propose to use porous-silicon-gettered MG-Si as a low-cost epitaxial substrate for polycrystalline silicon thin-film growth.

Investigation of the interface region between a porous silicon layer and a silicon substrate

International Nuclear Information System (INIS)

Lee, Ki-Won; Park, Dae-Kyu; Kim, Young-You; Shin, Hyun-Joon

2005-01-01

Atomic force microscopy (AFM) measurement and X-ray diffraction (XRD) analysis were performed to investigate the physical and structural characteristics of the interface region between a porous silicon layer and a silicon substrate. We discovered that, when anodization time was increased under a constant current density, the Si crystallites in the interface region became larger and formed different lattice parameters than observed in the porous silicon layer. Secondary ion mass spectrometry (SIMS) analysis also revealed that the Si was more concentrated in the interface region than in the porous silicon layer. These results were interpreted by the deficiency of the HF solution in reaching to the interface through the pores during the porous silicon formation

Vapor Pressure and Evaporation Coefficient of Silicon Monoxide over a Mixture of Silicon and Silica

Science.gov (United States)

Ferguson, Frank T.; Nuth, Joseph A., III

2012-01-01

The evaporation coefficient and equilibrium vapor pressure of silicon monoxide over a mixture of silicon and vitreous silica have been studied over the temperature range (1433 to 1608) K. The evaporation coefficient for this temperature range was (0.007 plus or minus 0.002) and is approximately an order of magnitude lower than the evaporation coefficient over amorphous silicon monoxide powder and in general agreement with previous measurements of this quantity. The enthalpy of reaction at 298.15 K for this reaction was calculated via second and third law analyses as (355 plus or minus 25) kJ per mol and (363.6 plus or minus 4.1) kJ per mol respectively. In comparison with previous work with the evaporation of amorphous silicon monoxide powder as well as other experimental measurements of the vapor pressure of silicon monoxide gas over mixtures of silicon and silica, these systems all tend to give similar equilibrium vapor pressures when the evaporation coefficient is correctly taken into account. This provides further evidence that amorphous silicon monoxide is an intimate mixture of small domains of silicon and silica and not strictly a true compound.

High temperature corrosion of silicon carbide and silicon nitride in the presence of chloride compound

International Nuclear Information System (INIS)

McNallan, M.

1993-01-01

Silicon carbide and silicon nitride are resistant to oxidation because a protective silicon dioxide films on their surfaces in most oxidizing environments. Chloride compounds can attack the surface in two ways: 1) chlorine can attack the silicon directly to form a volatile silicon chloride compound or 2) alkali compounds combined with the chlorine can be transported to the surface where they flux the silica layer by forming stable alkali silicates. Alkali halides have enough vapor pressure that a sufficient quantity of alkali species to cause accelerated corrosion can be transported to the ceramic surface without the formation of a chloride deposit. When silicon carbide is attacked simultaneously by chlorine and oxygen, the corrosion products include both volatile and condensed spices. Silicon nitride is much more resistance to this type of attack than silicon carbide. Silicon based ceramics are exposed to oxidizing gases in the presence of alkali chloride vapors, the rate of corrosion is controlled primarily by the driving force for the formation of alkali silicate, which can be quantified as the activity of the alkali oxide in equilibrium with the corrosive gas mixture. In a gas mixture containing a fixed partial pressure of KCl, the rate of corrosion is accelerated by increasing the concentration of water vapor and inhibited by increasing the concentration of HCl. Similar results have been obtained for mixtures containing other alkalis and halogens. (Orig./A.B.)

Effect of the internal rib structure of the inclusions on the two-dimensional phononic crystal composed of periodic slotted tubes in air

International Nuclear Information System (INIS)

Yu Kunpeng; Chen Tianning; Wang Xiaopeng; Zhou Anan

2012-01-01

Using a finite element method based on the Bloch theorem, a new phononic crystal composed of periodic slotted tubes with internal rib structure in air is investigated. Two parallel plates with slit are introduced into the inclusion as the internal rib structure and its effect on band gaps is studied. The band structure and acoustic modes of the PC are calculated. Results show that the starting frequency of the first band gap is rather lower than that of slotted tubes without rib structure. The internal rib structure plays an important role in both the lower and upper edges of the first band gap. Some rib structural parameters are also studied for their effects on the first band gap. Results show that the first gap can be modulated widely by these parameters and the Helmholtz resonator theory can be used to explain the relationship between the band gap and the parameters.

RBS/channeling analysis of hydrogen-implanted single crystals of FZ silicon and 6H silicon

International Nuclear Information System (INIS)

Irwin, R.B.

1984-01-01

Single crystals of FZ silicon and 6H silicon carbide were implanted with hydrogen ions (50 and 80 keV, respectively) to fluences from 2 x 10 16 H + /cm 2 to 2 x 10 18 H+/cm 2 . The implantations were carried out at three temperatures: approx.95K, 300 K, and approx.800 K. Swelling of the samples was measured by surface profilometry. RBS/channeling was used to obtain the damage profiles and to determine the amount of hydrogen retained in the lattice. The damage profiles are centered around X/sub m/ for the implants into silicon and around R/sub p/ for silicon carbide. For silicon carbide implanted at 95 K and 300 K and for silicon implanted at 95 K, the peak damage region is amorphous for fluences above 8 x 10 16 H + /cm 2 , 4 x 10 17 H + /cm 2 , and 2 x 10 17 H + /cm 2 , respectively. Silicon implanted at 300 and 800 K and silicon carbide implanted at 800 K remain crystalline up to fluences of 1 x 10 18 H + /cm 2 . The channeling damage results agree with previously reported TEM and electron diffraction data. The predictions of a simple disorder-accumulation model with a linear annealing term explains qualitatively the observed damage profiles in silicon carbide. Quantitatively, however, the model predicts faster development of the damage profiles than is observed at low fluences in both silicon and silicon carbide. For samples implanted at 300 and 800 K, the model also predicts substantially less peak disorder than is observed. The effect of the surface, the retained hydrogen, the shape of S/sub D/(X), and the need for a nonlinear annealing term may be responsible for the discrepancy

Quantum mechanical theory of epitaxial transformation of silicon to silicon carbide

International Nuclear Information System (INIS)

Kukushkin, S A; Osipov, A V

2017-01-01

The paper focuses on the study of transformation of silicon crystal into silicon carbide crystal via substitution reaction with carbon monoxide gas. As an example, the Si(1 0 0) surface is considered. The cross section of the potential energy surface of the first stage of transformation along the reaction pathway is calculated by the method of nudged elastic bands. It is found that in addition to intermediate states associated with adsorption of CO and SiO molecules on the surface, there is also an intermediate state in which all the atoms are strongly bonded to each other. This intermediate state significantly reduces the activation barrier of transformation down to 2.6 eV. The single imaginary frequencies corresponding to the two transition states of this transformation are calculated, one of which is reactant-like, whereas the other is product-like. By methods of quantum chemistry of solids, the second stage of this transformation is described, namely, the transformation of precarbide silicon into silicon carbide. Energy reduction per one cell is calculated for this ‘collapse’ process, and bond breaking energy is also found. Hence, it is concluded that the smallest size of the collapsing islet is 30 nm. It is shown that the chemical bonds of the initial silicon crystal are coordinately replaced by the bonds between Si and C in silicon carbide, which leads to a high quality of epitaxy and a low concentration of misfit dislocations. (paper)

Silicon Nanocrystal Synthesis in Microplasma Reactor

Science.gov (United States)

Nozaki, Tomohiro; Sasaki, Kenji; Ogino, Tomohisa; Asahi, Daisuke; Okazaki, Ken

Nanocrystalline silicon particles with grains smaller than 5 nm are widely recognized as a key material in optoelectronic devices, lithium battery electrodes, and bio-medical labels. Another important characteristic is that silicon is an environmentally safe material that is used in numerous silicon technologies. To date, several synthesis methods such as sputtering, laser ablation, and plasma-enhanced chemical vapor deposition (PECVD) based on low-pressure silane chemistry (SiH4) have been developed for precise control of size and density distributions of silicon nanocrystals. In this study, we explore the possibility of microplasma technologies for efficient production of mono-dispersed nanocrystalline silicon particles on a micrometer-scale, continuous-flow plasma reactor operated at atmospheric pressure. Mixtures of argon, hydrogen, and silicon tetrachloride were activated using a very-high-frequency (144 MHz) power source in a capillary glass tube with volume of less than 1 μl. Fundamental plasma parameters of the microplasma were characterized using optical emission spectroscopy, which respectively indicated electron density of 1015 cm-3, argon excitation temperature of 5000 K, and rotational temperature of 1500 K. Such high-density non-thermal reactive plasma can decompose silicon tetrachloride into atomic silicon to produce supersaturated silicon vapor, followed by gas-phase nucleation via three-body collision: particle synthesis in high-density plasma media is beneficial for promoting nucleation processes. In addition, further growth of silicon nuclei can be terminated in a short-residence-time reactor. Micro-Raman scattering spectra showed that as-deposited particles are mostly amorphous silicon with a small fraction of silicon nanocrystals. Transmission electron micrography confirmed individual 3-15 nm silicon nanocrystals. Although particles were not mono-dispersed, they were well separated and not coagulated.

Nanostructured silicon for thermoelectric

Science.gov (United States)

Stranz, A.; Kähler, J.; Waag, A.; Peiner, E.

2011-06-01

Thermoelectric modules convert thermal energy into electrical energy and vice versa. At present bismuth telluride is the most widely commercial used material for thermoelectric energy conversion. There are many applications where bismuth telluride modules are installed, mainly for refrigeration. However, bismuth telluride as material for energy generation in large scale has some disadvantages. Its availability is limited, it is hot stable at higher temperatures (>250°C) and manufacturing cost is relatively high. An alternative material for energy conversion in the future could be silicon. The technological processing of silicon is well advanced due to the rapid development of microelectronics in recent years. Silicon is largely available and environmentally friendly. The operating temperature of silicon thermoelectric generators can be much higher than of bismuth telluride. Today silicon is rarely used as a thermoelectric material because of its high thermal conductivity. In order to use silicon as an efficient thermoelectric material, it is necessary to reduce its thermal conductivity, while maintaining high electrical conductivity and high Seebeck coefficient. This can be done by nanostructuring into arrays of pillars. Fabrication of silicon pillars using ICP-cryogenic dry etching (Inductive Coupled Plasma) will be described. Their uniform height of the pillars allows simultaneous connecting of all pillars of an array. The pillars have diameters down to 180 nm and their height was selected between 1 micron and 10 microns. Measurement of electrical resistance of single silicon pillars will be presented which is done in a scanning electron microscope (SEM) equipped with nanomanipulators. Furthermore, measurement of thermal conductivity of single pillars with different diameters using the 3ω method will be shown.

A wide band slot-coupled beam sensing electrode for the advanced light source

International Nuclear Information System (INIS)

Hinkson, J.; Rex, K.

1991-05-01

Stripline electrodes (traveling wave electrodes, directional couplers) are commonly used in particle accelerators as beam pickups and kickers. The longitudinally symmetric stripline has a constant beam coupling impedance as a function of length and has a characteristic magnitude sin(x) amplitude response in the frequency domain. An experimentally tapered stripline provides nearly constant coupling impedance vs. frequency and yields superior frequency-domain performance. In practice it is difficult to construct either of these devices for broad-band performance because of the transition from coaxial to stripline geometry. We report on the construction of an exponentially-tapered, slot-coupled ''stripline'' which was relatively easy to construct and has the desired frequency response. 2 refs., 6 figs

Studies on the reactive melt infiltration of silicon and silicon-molybdenum alloys in porous carbon

Science.gov (United States)

Singh, M.; Behrendt, D. R.

1992-01-01

Investigations on the reactive melt infiltration of silicon and silicon-1.7 and 3.2 at percent molybdenum alloys into porous carbon preforms have been carried out by process modeling, differential thermal analysis (DTA) and melt infiltration experiments. These results indicate that the initial pore volume fraction of the porous carbon preform is a critical parameter in determining the final composition of the raction-formed silicon carbide and other residual phases. The pore size of the carbon preform is very detrimental to the exotherm temperatures due to liquid silicon-carbon reactions encountered during the reactive melt infiltration process. A possible mechanism for the liquid silicon-porous (glassy) carbon reaction has been proposed. The composition and microstructure of the reaction-formed silicon carbide has been discussed in terms of carbon preform microstructures, infiltration materials, and temperatures.

1366 Project Silicon: Reclaiming US Silicon PV Leadership

Energy Technology Data Exchange (ETDEWEB)

Lorenz, Adam [1366 Technologies, Bedford, MA (United States)

2016-02-16

1366 Technologies’ Project Silicon addresses two of the major goals of the DOE’s PV Manufacturing Initiative Part 2 program: 1) How to reclaim a strong silicon PV manufacturing presence and; 2) How to lower the levelized cost of electricity (“LCOE”) for solar to $0.05-$0.07/kWh, enabling wide-scale U.S. market adoption. To achieve these two goals, US companies must commercialize disruptive, high-value technologies that are capable of rapid scaling, defensible from foreign competition, and suited for US manufacturing. These are the aims of 1366 Technologies Direct Wafer ™ process. The research conducted during Project Silicon led to the first industrial scaling of 1366’s Direct Wafer™ process – an innovative, US-friendly (efficient, low-labor content) manufacturing process that destroys the main cost barrier limiting silicon PV cost-reductions: the 35-year-old grand challenge of making quality wafers (40% of the cost of modules) without the cost and waste of sawing. The SunPath program made it possible for 1366 Technologies to build its demonstration factory, a key and critical step in the Company’s evolution. The demonstration factory allowed 1366 to build every step of the process flow at production size, eliminating potential risk and ensuring the success of the Company’s subsequent scaling for a 1 GW factory to be constructed in Western New York in 2016 and 2017. Moreover, the commercial viability of the Direct Wafer process and its resulting wafers were established as 1366 formed key strategic partnerships, gained entry into the $8B/year multi-Si wafer market, and installed modules featuring Direct Wafer products – the veritable proving grounds for the technology. The program also contributed to the development of three Generation 3 Direct Wafer furnaces. These furnaces are the platform for copying intelligently and preparing our supply chain – large-scale expansion will not require a bigger machine but more machines. SunPath filled the

Silicon-micromachined microchannel plates

CERN Document Server

Beetz, C P; Steinbeck, J; Lemieux, B; Winn, D R

2000-01-01

Microchannel plates (MCP) fabricated from standard silicon wafer substrates using a novel silicon micromachining process, together with standard silicon photolithographic process steps, are described. The resulting SiMCP microchannels have dimensions of approx 0.5 to approx 25 mu m, with aspect ratios up to 300, and have the dimensional precision and absence of interstitial defects characteristic of photolithographic processing, compatible with positional matching to silicon electronics readouts. The open channel areal fraction and detection efficiency may exceed 90% on plates up to 300 mm in diameter. The resulting silicon substrates can be converted entirely to amorphous quartz (qMCP). The strip resistance and secondary emission are developed by controlled depositions of thin films, at temperatures up to 1200 deg. C, also compatible with high-temperature brazing, and can be essentially hydrogen, water and radionuclide-free. Novel secondary emitters and cesiated photocathodes can be high-temperature deposite...

Porous silicon carbide (SIC) semiconductor device

Science.gov (United States)

Shor, Joseph S. (Inventor); Kurtz, Anthony D. (Inventor)

1996-01-01

Porous silicon carbide is fabricated according to techniques which result in a significant portion of nanocrystallites within the material in a sub 10 nanometer regime. There is described techniques for passivating porous silicon carbide which result in the fabrication of optoelectronic devices which exhibit brighter blue luminescence and exhibit improved qualities. Based on certain of the techniques described porous silicon carbide is used as a sacrificial layer for the patterning of silicon carbide. Porous silicon carbide is then removed from the bulk substrate by oxidation and other methods. The techniques described employ a two-step process which is used to pattern bulk silicon carbide where selected areas of the wafer are then made porous and then the porous layer is subsequently removed. The process to form porous silicon carbide exhibits dopant selectivity and a two-step etching procedure is implemented for silicon carbide multilayers.

Silicon Photonics Cloud (SiCloud)

DEFF Research Database (Denmark)

DeVore, P. T. S.; Jiang, Y.; Lynch, M.

2015-01-01

Silicon Photonics Cloud (SiCloud.org) is the first silicon photonics interactive web tool. Here we report new features of this tool including mode propagation parameters and mode distribution galleries for user specified waveguide dimensions and wavelengths.......Silicon Photonics Cloud (SiCloud.org) is the first silicon photonics interactive web tool. Here we report new features of this tool including mode propagation parameters and mode distribution galleries for user specified waveguide dimensions and wavelengths....

Current-drive on the Versator-II tokamak with a slotted-waveguide fast-wave coupler

International Nuclear Information System (INIS)

Colborn, J.A.

1987-11-01

A slotted-waveguide fast-wave coupler has been constructed, without dielectric, and used to drive current on the Versator-II tokamak. Up to 35 kW of net microwave power at 2.45 GHz has been radiated into plasmas with 2 x 10 12 cm -3 ≤ mean of n/sub e/ ≤ 1.2 x 10 13 cm -3 and B/sub tor/ ≅ 1.0 T. The launched spectrum had a peak near N/sub parallel/ = -2.0 and a larger peak near N/sub parallel/ = 0.7. Radiating efficiency of the antenna was roughly independent of antenna position except when the antenna was at least 0.2 cm outside the limiter, in which case the radiating efficiency slightly improved as the antenna was moved farther outside. When the coupler was inside the limiter, radiating efficiency improved moderately with increased mean of n/sub e/. Current-drive efficiency was comparable to that of the slow wave and was not affected when the antenna spectrum was reversed; however, no current was driven for mean of n/sub e/ ≤ 2 x 10 12 cm -3 . These results indicate the fast wave was launched, but a substantial part of the power may have been mode-converted to the slow wave, possibly via a downshift in N/sub parallel/, and these slow waves may have been responsible for most of the driven current. Relevant theory for waves in plasma, current-drive efficiency, and coupling of the slotted-waveguide is discussed, the antenna design method is explained, and future work, including the construction of a much-improved probe-fed antenna, is described. 42 refs., 45 figs

Slotted rotatable target assembly and systematic error analysis for a search for long range spin dependent interactions from exotic vector boson exchange using neutron spin rotation

Science.gov (United States)

Haddock, C.; Crawford, B.; Fox, W.; Francis, I.; Holley, A.; Magers, S.; Sarsour, M.; Snow, W. M.; Vanderwerp, J.

2018-03-01

We discuss the design and construction of a novel target array of nonmagnetic test masses used in a neutron polarimetry measurement made in search for new possible exotic spin dependent neutron-atominteractions of Nature at sub-mm length scales. This target was designed to accept and efficiently transmit a transversely polarized slow neutron beam through a series of long open parallel slots bounded by flat rectangular plates. These openings possessed equal atom density gradients normal to the slots from the flat test masses with dimensions optimized to achieve maximum sensitivity to an exotic spin-dependent interaction from vector boson exchanges with ranges in the mm - μm regime. The parallel slots were oriented differently in four quadrants that can be rotated about the neutron beam axis in discrete 90°increments using a Geneva drive. The spin rotation signals from the 4 quadrants were measured using a segmented neutron ion chamber to suppress possible systematic errors from stray magnetic fields in the target region. We discuss the per-neutron sensitivity of the target to the exotic interaction, the design constraints, the potential sources of systematic errors which could be present in this design, and our estimate of the achievable sensitivity using this method.

The silicon-silicon oxide multilayers utilization as intrinsic layer on pin solar cells

International Nuclear Information System (INIS)

Colder, H.; Marie, P.; Gourbilleau, F.

2008-01-01

Silicon nanostructures are promising candidate for the intrinsic layer on pin solar cells. In this work we report on new material: silicon-rich silicon oxide (SRSO) deposited by reactive magnetron sputtering of a pure silica target and an interesting structure: multilayers consisting of a stack of SRSO and pure silicon oxide layers. Two thicknesses of the SRSO sublayer, t SRSO , are studied 3 nm and 5 nm whereas the thickness of silica sublayer is maintaining at 3 nm. The presence of nanocrystallites of silicon, evidenced by X-Ray diffraction (XRD), leads to photoluminescence (PL) emission at room temperature due to the quantum confinement of the carriers. The PL peak shifts from 1.3 eV to 1.5 eV is correlated to the decreasing of t SRSO from 5 nm down to 3 nm. In the purpose of their potential utilization for i-layer, the optical properties are studied by absorption spectroscopy. The achievement a such structures at promising absorption properties. Moreover by favouring the carriers injection by the tunnel effect between silicon nanograins and silica sublayers, the multilayers seem to be interesting for solar cells

Method of forming buried oxide layers in silicon

Science.gov (United States)

Sadana, Devendra Kumar; Holland, Orin Wayne

2000-01-01

A process for forming Silicon-On-Insulator is described incorporating the steps of ion implantation of oxygen into a silicon substrate at elevated temperature, ion implanting oxygen at a temperature below 200.degree. C. at a lower dose to form an amorphous silicon layer, and annealing steps to form a mixture of defective single crystal silicon and polycrystalline silicon or polycrystalline silicon alone and then silicon oxide from the amorphous silicon layer to form a continuous silicon oxide layer below the surface of the silicon substrate to provide an isolated superficial layer of silicon. The invention overcomes the problem of buried isolated islands of silicon oxide forming a discontinuous buried oxide layer.

Effects of ion implantation on charges in the silicon--silicon dioxide system

International Nuclear Information System (INIS)

Learn, A.J.; Hess, D.W.

1977-01-01

Structures consisting of thermally grown oxide on silicon were implanted with boron, arsenic, or argon ions. For argon implantation through oxides, an increased fixed oxide charge (Q/sub ss/) was observed with the increase being greater for than for silicon. This effect is attributed to oxygen recoil which produces additional excess ionized silicon in the oxide of a type similar to that arising in thermal oxidation. Fast surface state (N/sub st/) generation was also noted which in most cases obscured the Q/sub ss/ increase. Of various heat treatments tested, only a 900 degreeC anneal in hydrogen annihilated N/sub st/ and allowed Q/sub ss/ measurement. Such N/sub st/ apparently arises as a consequence of implantation damage at the silicon--silicon dioxide interface. With the exception of boron implantations into thick oxides or through aluminum electrodes, reduction of the mobile ionic charge (Q/sub o/) was achieved by implantation. The reduction again is presumably damage related and is not negated by high-temperature annealing but may be counterbalanced by aluminum incorporation in the oxide

High Efficiency, Low Cost Solar Cells Manufactured Using 'Silicon Ink' on Thin Crystalline Silicon Wafers

Energy Technology Data Exchange (ETDEWEB)

Antoniadis, H.

2011-03-01

Reported are the development and demonstration of a 17% efficient 25mm x 25mm crystalline Silicon solar cell and a 16% efficient 125mm x 125mm crystalline Silicon solar cell, both produced by Ink-jet printing Silicon Ink on a thin crystalline Silicon wafer. To achieve these objectives, processing approaches were developed to print the Silicon Ink in a predetermined pattern to form a high efficiency selective emitter, remove the solvents in the Silicon Ink and fuse the deposited particle Silicon films. Additionally, standard solar cell manufacturing equipment with slightly modified processes were used to complete the fabrication of the Silicon Ink high efficiency solar cells. Also reported are the development and demonstration of a 18.5% efficient 125mm x 125mm monocrystalline Silicon cell, and a 17% efficient 125mm x 125mm multicrystalline Silicon cell, by utilizing high throughput Ink-jet and screen printing technologies. To achieve these objectives, Innovalight developed new high throughput processing tools to print and fuse both p and n type particle Silicon Inks in a predetermined pat-tern applied either on the front or the back of the cell. Additionally, a customized Ink-jet and screen printing systems, coupled with customized substrate handling solution, customized printing algorithms, and a customized ink drying process, in combination with a purchased turn-key line, were used to complete the high efficiency solar cells. This development work delivered a process capable of high volume producing 18.5% efficient crystalline Silicon solar cells and enabled the Innovalight to commercialize its technology by the summer of 2010.

Silicon-micromachined microchannel plates

International Nuclear Information System (INIS)

Beetz, Charles P.; Boerstler, Robert; Steinbeck, John; Lemieux, Bryan; Winn, David R.

2000-01-01

Microchannel plates (MCP) fabricated from standard silicon wafer substrates using a novel silicon micromachining process, together with standard silicon photolithographic process steps, are described. The resulting SiMCP microchannels have dimensions of ∼0.5 to ∼25 μm, with aspect ratios up to 300, and have the dimensional precision and absence of interstitial defects characteristic of photolithographic processing, compatible with positional matching to silicon electronics readouts. The open channel areal fraction and detection efficiency may exceed 90% on plates up to 300 mm in diameter. The resulting silicon substrates can be converted entirely to amorphous quartz (qMCP). The strip resistance and secondary emission are developed by controlled depositions of thin films, at temperatures up to 1200 deg. C, also compatible with high-temperature brazing, and can be essentially hydrogen, water and radionuclide-free. Novel secondary emitters and cesiated photocathodes can be high-temperature deposited or nucleated in the channels or the first strike surface. Results on resistivity, secondary emission and gain are presented

CIRCULARLY POLARIZED SLOTTED APERTURE ANTENNA WITH COPLANAR WAVEGUIDE FED FOR BROADBAND APPLICATIONS

Directory of Open Access Journals (Sweden)

B. T. P. MADHAV

2016-02-01

Full Text Available Coplanar waveguide fed circularly polarized microstrip patch antenna performance evaluation is presented in this paper. The broadband characteristics are attained by placing open end slot at the lower side of the antenna. The proposed design has the return loss of less than -10dB and VSWR<2 in the desired band of operation. A gain of 3dB to 4dB is attained in the desired band with good radiation characteristics and a suitable axial ratio of less than 3 dB is attained in the prescribed band of operation. Proposed antenna is fabricated on the FR4 substrate with dielectric constant of 4.4. Parametric analysis with change in substrate permittivity also performed and the optimized dimensions are presented in this work.

High precision slotted cavity measurement of a novel ceramic state polymer electrolyte

Science.gov (United States)

Quan, Wei; NurulAfsar, Mohammed

2018-01-01

Thin film materials are already used in a variety of microwave and higher frequency applications such as electrically tunable microwave devices, integrated circuits like MMICs, radomes, and radar absorbing coating. The determination of the dielectric properties of these films is thus of significant importance. The measurement of complex dielectric permittivity of thin films is very difficult at microwave, millimeter, and THz frequencies because both the amplitude change and phase shift are not large enough to evaluate the real part of the dielectric permittivity. A specially designed transverse slotted cavity for X-band microwave measurement has been designed and constructed to employ with a vector network analyzer to evaluate the real part of dielectric permittivity of thin films accurately and conveniently. Commercially available polymer thin films are measured to validate the methods.

Removal of inclusions from silicon

Science.gov (United States)

Ciftja, Arjan; Engh, Thorvald Abel; Tangstad, Merete; Kvithyld, Anne; Øvrelid, Eivind Johannes

2009-11-01

The removal of inclusions from molten silicon is necessary to satisfy the purity requirements for solar grade silicon. This paper summarizes two methods that are investigated: (i) settling of the inclusions followed by subsequent directional solidification and (infiltration by ceramic foam filters. Settling of inclusions followed by directional solidification is of industrial importance for production of low-cost solar grade silicon. Filtration is reported as the most efficient method for removal of inclusions from the top-cut silicon scrap.

Silicon Tracking Upgrade at CDF

International Nuclear Information System (INIS)

Kruse, M.C.

1998-04-01

The Collider Detector at Fermilab (CDF) is scheduled to begin recording data from Run II of the Fermilab Tevatron in early 2000. The silicon tracking upgrade constitutes both the upgrade to the CDF silicon vertex detector (SVX II) and the new Intermediate Silicon Layers (ISL) located at radii just beyond the SVX II. Here we review the design and prototyping of all aspects of these detectors including mechanical design, data acquisition, and a trigger based on silicon tracking

Radiation Hardening of Silicon Detectors

CERN Multimedia

Leroy, C; Glaser, M

2002-01-01

%RD48 %title\\\\ \\\\Silicon detectors will be widely used in experiments at the CERN Large Hadron Collider where high radiation levels will cause significant bulk damage. In addition to increased leakage current and charge collection losses worsening the signal to noise, the induced radiation damage changes the effective doping concentration and represents the limiting factor to long term operation of silicon detectors. The objectives are to develop radiation hard silicon detectors that can operate beyond the limits of the present devices and that ensure guaranteed operation for the whole lifetime of the LHC experimental programme. Radiation induced defect modelling and experimental results show that the silicon radiation hardness depends on the atomic impurities present in the initial monocrystalline material.\\\\ \\\\ Float zone (FZ) silicon materials with addition of oxygen, carbon, nitrogen, germanium and tin were produced as well as epitaxial silicon materials with epilayers up to 200 $\\mu$m thickness. Their im...

Silicon Alloying On Aluminium Based Alloy Surface

International Nuclear Information System (INIS)

Suryanto

2002-01-01

Silicon alloying on surface of aluminium based alloy was carried out using electron beam. This is performed in order to enhance tribological properties of the alloy. Silicon is considered most important alloying element in aluminium alloy, particularly for tribological components. Prior to silicon alloying. aluminium substrate were painted with binder and silicon powder and dried in a furnace. Silicon alloying were carried out in a vacuum chamber. The Silicon alloyed materials were assessed using some techniques. The results show that silicon alloying formed a composite metal-non metal system in which silicon particles are dispersed in the alloyed layer. Silicon content in the alloyed layer is about 40% while in other place is only 10.5 %. The hardness of layer changes significantly. The wear properties of the alloying alloys increase. Silicon surface alloying also reduced the coefficient of friction for sliding against a hardened steel counter face, which could otherwise be higher because of the strong adhesion of aluminium to steel. The hardness of the silicon surface alloyed material dropped when it underwent a heating cycle similar to the ion coating process. Hence, silicon alloying is not a suitable choice for use as an intermediate layer for duplex treatment

Testing and evaluation of a slot and tab construction technique for light-weight wood-fiber-based structural panels under bending

Science.gov (United States)

Jinghao Li; John F. Hunt; Shaoqin Gong; Zhiyong Cai

2015-01-01

This paper presented construction and strain distributions for light-weight wood-fiber-based structural panels with tri-grid core made from phenolic impregnated laminated paper composites under bending. A new fastening configuration of slots in the faces and tabs on the core was applied to the face/core interfaces of the sandwich panel in addition to epoxy resin. Both...

Comparing of cogging torque reduction methods in permanent magnet machines with fractional slot windings

Science.gov (United States)

Pristup, A. G.; Toporkov, D. M.

2017-10-01

The results of the investigation of the cogging torque in permanent magnet synchronous machines, which is caused by the stator slotting and the rotor eccentricity, are presented in the paper. A new design of the machine has been developed in the course of the investigation, and the value of the cogging torque in this construction is less considerably compared to other constructions. In contrast to the available methods of the cogging torque reduction, the solution suggested not only decreases the level of the cogging torque but also has negligibly small influence on characteristics of the machine with the rotor eccentricity which is typical of the mass production and long-term usage.

Characteristics of pitch angle distributions of hundreds of keV electrons in the slot region and inner radiation belt

Science.gov (United States)

Zhao, H.; Li, X.; Blake, J. B.; Fennell, J. F.; Claudepierre, S. G.; Baker, D. N.; Jaynes, A. N.; Malaspina, D. M.

2014-12-01

The pitch angle distribution (PAD) of energetic electrons in the slot region and inner radiation belt received little attention in the past decades due to the lack of quality measurements. Using the state-of-the-art pitch angle-resolved data from the Magnetic Electron Ion Spectrometer instrument onboard the Van Allen Probes, a detailed analysis of hundreds of keV electron PADs below L = 4 is performed, in which the PADs are categorized into three types: normal (flux peaking at 90°), cap (exceedingly peaking narrowly around 90°), and 90° minimum (lower flux at 90°) PADs. By examining the characteristics of the PADs of ˜460 keV electrons for over a year, we find that the 90° minimum PADs are generally present in the inner belt (Lpitch angle scattering of hiss waves. Fitting the normal PADs into sinnα form, the parameter n is much higher below L = 3 than that in the outer belt and relatively constant in the inner belt but changes significantly in the slot region (2 mechanism can hardly explain the formation of 90° minimum PADs at the center of inner belt.

Silicon microfabricated beam expander

Science.gov (United States)

Othman, A.; Ibrahim, M. N.; Hamzah, I. H.; Sulaiman, A. A.; Ain, M. F.

2015-03-01

The feasibility design and development methods of silicon microfabricated beam expander are described. Silicon bulk micromachining fabrication technology is used in producing features of the structure. A high-precision complex 3-D shape of the expander can be formed by exploiting the predictable anisotropic wet etching characteristics of single-crystal silicon in aqueous Potassium-Hydroxide (KOH) solution. The beam-expander consist of two elements, a micromachined silicon reflector chamber and micro-Fresnel zone plate. The micro-Fresnel element is patterned using lithographic methods. The reflector chamber element has a depth of 40 µm, a diameter of 15 mm and gold-coated surfaces. The impact on the depth, diameter of the chamber and absorption for improved performance are discussed.