A high sensitivity 20Mfps CMOS image sensor with readout speed of 1Tpixel/sec for visualization of ultra-high speed phenomena

Science.gov (United States)

Kuroda, R.; Sugawa, S.

2017-02-01

Ultra-high speed (UHS) CMOS image sensors with on-chop analog memories placed on the periphery of pixel array for the visualization of UHS phenomena are overviewed in this paper. The developed UHS CMOS image sensors consist of 400H×256V pixels and 128 memories/pixel, and the readout speed of 1Tpixel/sec is obtained, leading to 10 Mfps full resolution video capturing with consecutive 128 frames, and 20 Mfps half resolution video capturing with consecutive 256 frames. The first development model has been employed in the high speed video camera and put in practical use in 2012. By the development of dedicated process technologies, photosensitivity improvement and power consumption reduction were simultaneously achieved, and the performance improved version has been utilized in the commercialized high-speed video camera since 2015 that offers 10 Mfps with ISO16,000 photosensitivity. Due to the improved photosensitivity, clear images can be captured and analyzed even under low light condition, such as under a microscope as well as capturing of UHS light emission phenomena.

Cutting efficiency of diamond burs operated with electric high-speed dental handpiece on zirconia.

Science.gov (United States)

Nakamura, Keisuke; Katsuda, Yusuke; Ankyu, Shuhei; Harada, Akio; Tenkumo, Taichi; Kanno, Taro; Niwano, Yoshimi; Egusa, Hiroshi; Milleding, Percy; Örtengren, Ulf

2015-10-01

Zirconia-based dental restorations are becoming used more commonly. However, limited attention has been given to the difficulties experienced, concerning cutting, in removing the restorations when needed. The aim of the present study was to compare the cutting efficiency of diamond burs, operated using an electric high-speed dental handpiece, on zirconia (Zir) with those on lithium disilicate glass-ceramic (LD) and leucite glass-ceramic (L). In addition, evaluation of the cutting efficiency of diamond burs on Zir of different thicknesses was performed. Specimens of Zir were prepared with thicknesses of 0.5, 1.0, 2.0, and 4.0 mm, and specimens of LD and L were prepared with a thickness of 1.0 mm. Cutting tests were performed using diamond burs with super coarse (SC) and coarse (C) grains. The handpiece was operated at 150,000 rpm with a cutting force of 0.9 N. The results demonstrated that cutting of Zir took about 1.5- and 7-fold longer than cutting of LD and L, respectively. The SC grains showed significantly higher cutting efficiency on Zir than the C grains. However, when the thickness of Zir increased, the cutting depth was significantly decreased. As it is suggested that cutting of zirconia is time consuming, this should be taken into consideration in advance when working with zirconia restorations. © 2015 Eur J Oral Sci.

Ultra-high-speed inversion recovery echo planar MR imaging

International Nuclear Information System (INIS)

Stehling, M.K.; Ordidge, R.J.; Coxon, R.; Chapman, B.; Houseman, A.M.; Guifoyle, D.; Blamire, A.; Gibbs, P.; Mansfield, P.

1988-01-01

Fast two-dimensional FT MR imaging techniques such as fast low-angle shot do not allow inversion recovery (IR). Rapid repetition of low-angle pulses is incompatible with a 180 0 inversion pulse. Echo planar imaging (EPI) can be applied in conjunction with IR, because after preparation of the spin system, a complete image is acquired. Data acquisition in less than 100 msec and real-time display allows interactive optimization of inversion time (4.0-9,000 msec) with little time penalty. The authors have applied IR EPI to the study of the brain, liver, and kidneys in normal volunteers and patients. Technical details are presented, and the applications of this first ultra-high-speed IR technique will be shown

TRANSFORMATIONS IN NANO-DIAMONDS WITH FORMATION OF NANO-POROUS SILICON CARBIDE AT HIGH PRESSURE

Directory of Open Access Journals (Sweden)

V. N. Kovalevsky

2010-01-01

Full Text Available The paper contains investigations on regularities of diamond - silicon carbide composite structure formation at impact-wave excitation. It has been determined that while squeezing a porous blank containing Si (SiC nano-diamond by explosive detonation products some processes are taking place such as diamond nano-particles consolidation, reverse diamond transition into graphite, fragments formation from silicon carbide. A method for obtaining high-porous composites with the presence of ultra-disperse diamond particles has been developed. Material with three-dimensional high-porous silicon-carbide structure has been received due to nano-diamond graphitation at impact wave transmission and plastic deformation. The paper reveals nano-diamonds inverse transformation into graphite and its subsequent interaction with the silicon accompanied by formation of silicon-carbide fragments with dimensions of up to 100 nm.

ASBESTOS EXPOSURES DURING ROUTINE FLOOR TILE MAINTENANCE. PART 2: ULTRA HIGH SPEED BURNISHING AND WET-STRIPPING

Science.gov (United States)

This study was conducted to evaluate airborne asbestos concentrations during ultra high speed (UHS) burnishing and wet-stripping of asbestos-containing resilient floor tile under two levels of floor care condition (poor and good). Airborne asbestos concentrations were measured by...

Ultra-high-speed digital in-line holography system applied to particle-laden supersonic underexpanded jet flows

DEFF Research Database (Denmark)

Ingvorsen, Kristian Mark; Buchmann, Nicolas A.; Soria, Julio

2012-01-01

-fluid interactions in these high-speed flows special high performance techniques are required. The present work is an investigation into the applicability of magnified digital in-line holography with ultra-high-speed recording for the study of three-dimensional supersonic particle-laden flows. An optical setup...... × 10mm calibration grid and 120 μm particles on a glass plate. In the case with the calibration grid it is found that accurate determination of the depthwise position is possible. However, when applying the same technique to the particle target, significant problems are encountered. © 2012...

Modeling of Diamond Field-Emitter-Arrays for high brightness photocathode applications

Science.gov (United States)

Kwan, Thomas; Huang, Chengkun; Piryatinski, Andrei; Lewellen, John; Nichols, Kimberly; Choi, Bo; Pavlenko, Vitaly; Shchegolkov, Dmitry; Nguyen, Dinh; Andrews, Heather; Simakov, Evgenya

2017-10-01

We propose to employ Diamond Field-Emitter-Arrays (DFEAs) as high-current-density ultra-low-emittance photocathodes for compact laser-driven dielectric accelerators capable of generating ultra-high brightness electron beams for advanced applications. We develop a semi-classical Monte-Carlo photoemission model for DFEAs that includes carriers' transport to the emitter surface and tunneling through the surface under external fields. The model accounts for the electronic structure size quantization affecting the transport and tunneling process within the sharp diamond tips. We compare this first principle model with other field emission models, such as the Child-Langmuir and Murphy-Good models. By further including effects of carrier photoexcitation, we perform simulations of the DFEAs' photoemission quantum yield and the emitted electron beam. Details of the theoretical model and validation against preliminary experimental data will be presented. Work ssupported by LDRD program at LANL.

Performance analysis of InSb based QWFET for ultra high speed applications

International Nuclear Information System (INIS)

Subash, T. D.; Gnanasekaran, T.; Divya, C.

2015-01-01

An indium antimonide based QWFET (quantum well field effect transistor) with the gate length down to 50 nm has been designed and investigated for the first time for L-band radar applications at 230 GHz. QWFETs are designed at the high performance node of the International Technology Road Map for Semiconductors (ITRS) requirements of drive current (Semiconductor Industry Association 2010). The performance of the device is investigated using the SYNOPSYS CAD (TCAD) software. InSb based QWFET could be a promising device technology for very low power and ultra-high speed performance with 5–10 times low DC power dissipation. (semiconductor devices)

Isotopically Enriched C-13 Diamond Anvil as a Stress Sensor in High Pressure Experiments

Science.gov (United States)

Vohra, Yogesh; Qiu, Wei; Kondratyev, Andreiy; Velisavljevic, Nenad; Baker, Paul

2004-03-01

The conventional high pressure diamond anvils were modified by growing an isotopically pure C-13 diamond layer by microwave plasma chemical vapor deposition using methane/hydrogen/oxygen chemistry. The isotopically pure C-13 nature of the culet of the diamond anvil was confirmed by the Raman spectroscopy measurements. This isotopically engineered diamond anvil was used against a natural abundance diamond anvil for high pressure experiments in a diamond anvil cell. Spatial resolved Raman spectroscopy was used to measure the stress induced shift in the C-13 layer as well as the undelying C-12 layer to ultra high pressures. The observed shift and splitiing of the diamond first order Raman spectrum was correlated with the stress distribution in the diamond anvil cell. The experimental results will be compared with the finite element modeling results using NIKE-2D software in order to create a mathematical relationship between sets of the following parameters: vertical (z axis) distance; horizontal (r axis) distance; max shear stress, and pressure. The isotopically enriched diamond anvils offer unique opportunities to measure stress distribution in the diamond anvil cell devices.

An ultra-precision tool nanoindentation instrument for replication of single point diamond tool cutting edges

Science.gov (United States)

Cai, Yindi; Chen, Yuan-Liu; Xu, Malu; Shimizu, Yuki; Ito, So; Matsukuma, Hiraku; Gao, Wei

2018-05-01

Precision replication of the diamond tool cutting edge is required for non-destructive tool metrology. This paper presents an ultra-precision tool nanoindentation instrument designed and constructed for replication of the cutting edge of a single point diamond tool onto a selected soft metal workpiece by precisely indenting the tool cutting edge into the workpiece surface. The instrument has the ability to control the indentation depth with a nanometric resolution, enabling the replication of tool cutting edges with high precision. The motion of the diamond tool along the indentation direction is controlled by the piezoelectric actuator of a fast tool servo (FTS). An integrated capacitive sensor of the FTS is employed to detect the displacement of the diamond tool. The soft metal workpiece is attached to an aluminum cantilever whose deflection is monitored by another capacitive sensor, referred to as an outside capacitive sensor. The indentation force and depth can be accurately evaluated from the diamond tool displacement, the cantilever deflection and the cantilever spring constant. Experiments were carried out by replicating the cutting edge of a single point diamond tool with a nose radius of 2.0 mm on a copper workpiece surface. The profile of the replicated tool cutting edge was measured using an atomic force microscope (AFM). The effectiveness of the instrument in precision replication of diamond tool cutting edges is well-verified by the experimental results.

High-speed ultra-wideband wireless signals over fiber systems: photonic generation and DSP detection

DEFF Research Database (Denmark)

Yu, Xianbin; Gibbon, Timothy Braidwood; Tafur Monroy, Idelfonso

2009-01-01

We firstly review the efforts in the literature on ultra-wideband (UWB)-over-fiber systems. Secondly, we present experimental results on photonic generation of high-speed UWB signals by both direct modulation and external optical injecting an uncooled semiconductor laser. Furthermore, we introduce...... the use of digital signal processing (DSP) technology to receive the generated UWB signal at 781.25 Mbit/s. Error-free transmission is achieved....

Single-event transient imaging with an ultra-high-speed temporally compressive multi-aperture CMOS image sensor.

Science.gov (United States)

Mochizuki, Futa; Kagawa, Keiichiro; Okihara, Shin-ichiro; Seo, Min-Woong; Zhang, Bo; Takasawa, Taishi; Yasutomi, Keita; Kawahito, Shoji

2016-02-22

In the work described in this paper, an image reproduction scheme with an ultra-high-speed temporally compressive multi-aperture CMOS image sensor was demonstrated. The sensor captures an object by compressing a sequence of images with focal-plane temporally random-coded shutters, followed by reconstruction of time-resolved images. Because signals are modulated pixel-by-pixel during capturing, the maximum frame rate is defined only by the charge transfer speed and can thus be higher than those of conventional ultra-high-speed cameras. The frame rate and optical efficiency of the multi-aperture scheme are discussed. To demonstrate the proposed imaging method, a 5×3 multi-aperture image sensor was fabricated. The average rising and falling times of the shutters were 1.53 ns and 1.69 ns, respectively. The maximum skew among the shutters was 3 ns. The sensor observed plasma emission by compressing it to 15 frames, and a series of 32 images at 200 Mfps was reconstructed. In the experiment, by correcting disparities and considering temporal pixel responses, artifacts in the reconstructed images were reduced. An improvement in PSNR from 25.8 dB to 30.8 dB was confirmed in simulations.

Note: Evaluation of microfracture strength of diamond materials using nano-polycrystalline diamond spherical indenter

Science.gov (United States)

Sumiya, H.; Hamaki, K.; Harano, K.

2018-05-01

Ultra-hard and high-strength spherical indenters with high precision and sphericity were successfully prepared from nanopolycrystalline diamond (NPD) synthesized by direct conversion sintering from graphite under high pressure and high temperature. It was shown that highly accurate and stable microfracture strength tests can be performed on various super-hard diamond materials by using the NPD spherical indenters. It was also verified that this technique enables quantitative evaluation of the strength characteristics of single crystal diamonds and NPDs which have been quite difficult to evaluate.

Ultra-high-speed digital in-line holography system applied to particle-laden supersonic underexpanded jet flows

DEFF Research Database (Denmark)

Ingvorsen, Kristian Mark; Buchmann, Nicolas A.; Soria, Julio

2012-01-01

-fluid interactions in these high-speed flows special high performance techniques are required. The present work is an investigation into the applicability of magnified digital in-line holography with ultra-high-speed recording for the study of three-dimensional supersonic particle-laden flows. An optical setup...... × 10mm calibration grid and 120 μm particles on a glass plate. In the case with the calibration grid it is found that accurate determination of the depthwise position is possible. However, when applying the same technique to the particle target, significant problems are encountered....

Micro-architecture embedding ultra-thin interlayer to bond diamond and silicon via direct fusion

Science.gov (United States)

Kim, Jong Cheol; Kim, Jongsik; Xin, Yan; Lee, Jinhyung; Kim, Young-Gyun; Subhash, Ghatu; Singh, Rajiv K.; Arjunan, Arul C.; Lee, Haigun

2018-05-01

The continuous demand on miniaturized electronic circuits bearing high power density illuminates the need to modify the silicon-on-insulator-based chip architecture. This is because of the low thermal conductivity of the few hundred nanometer-thick insulator present between the silicon substrate and active layers. The thick insulator is notorious for releasing the heat generated from the active layers during the operation of devices, leading to degradation in their performance and thus reducing their lifetime. To avoid the heat accumulation, we propose a method to fabricate the silicon-on-diamond (SOD) microstructure featured by an exceptionally thin silicon oxycarbide interlayer (˜3 nm). While exploiting the diamond as an insulator, we employ spark plasma sintering to render the silicon directly fused to the diamond. Notably, this process can manufacture the SOD microarchitecture via a simple/rapid way and incorporates the ultra-thin interlayer for minute thermal resistance. The method invented herein expects to minimize the thermal interfacial resistance of the devices and is thus deemed as a breakthrough appealing to the current chip industry.

Ultra-high performance mirror systems for the imaging and coherence beamline I13 at the Diamond Light Source

Science.gov (United States)

Wagner, U. H.; Alcock, S.; Ludbrook, G.; Wiatryzk, J.; Rau, C.

2012-05-01

I13L is a 250m long hard x-ray beamline (6 keV to 35 keV) currently under construction at the Diamond Light Source. The beamline comprises of two independent experimental endstations: one for imaging in direct space using x-ray microscopy and one for imaging in reciprocal space using coherent diffraction based imaging techniques. To minimise the impact of thermal fluctuations and vibrations onto the beamline performance, we are developing a new generation of ultra-stable beamline instrumentation with highly repeatable adjustment mechanisms using low thermal expansion materials like granite and large piezo-driven flexure stages. For minimising the beam distortion we use very high quality optical components like large ion-beam polished mirrors. In this paper we present the first metrology results on a newly designed mirror system following this design philosophy.

Research and Application of WCF Technology in Data Acquisition of Ultra-high Speed Packaging Machine

Directory of Open Access Journals (Sweden)

Qian Jie

2016-01-01

Full Text Available By introducing WCF technology on data acquisition of ultra-high speed packaging machine, data acquisition system reads dates of machine in polling mode through the WCF client, which can achieve accurate data collection, and effectively isolate the data acquisition system and the machine control system. It enhances the security of data interaction between systems, but also reduces the coupling degree between systems.

Ultra-high speed all-optical signal processing using silicon waveguides and a carbon nanotubes based mode-locked laser

DEFF Research Database (Denmark)

Ji, Hua

This thesis concerns the use of nano-engineered silicon waveguides for ultra-high speed optical serial data signal processing. The fundamental nonlinear properties of nano-engineered silicon waveguides are characterized. Utilizing the nonlinear effect in nano-engineered silicon waveguides for dem...

Efficient Ultra-High Speed Communication with Simultaneous Phase and Amplitude Regenerative Sampling (SPARS)

Science.gov (United States)

Carlowitz, Christian; Girg, Thomas; Ghaleb, Hatem; Du, Xuan-Quang

2017-09-01

For ultra-high speed communication systems at high center frequencies above 100 GHz, we propose a disruptive change in system architecture to address major issues regarding amplifier chains with a large number of amplifier stages. They cause a high noise figure and high power consumption when operating close to the frequency limits of the underlying semiconductor technologies. Instead of scaling a classic homodyne transceiver system, we employ repeated amplification in single-stage amplifiers through positive feedback as well as synthesizer-free self-mixing demodulation at the receiver to simplify the system architecture notably. Since the amplitude and phase information for the emerging oscillation is defined by the input signal and the oscillator is only turned on for a very short time, it can be left unstabilized and thus come without a PLL. As soon as gain is no longer the most prominent issue, relaxed requirements for all the other major components allow reconsidering their implementation concepts to achieve further improvements compared to classic systems. This paper provides the first comprehensive overview of all major design aspects that need to be addressed upon realizing a SPARS-based transceiver. At system level, we show how to achieve high data rates and a noise performance comparable to classic systems, backed by scaled demonstrator experiments. Regarding the transmitter, design considerations for efficient quadrature modulation are discussed. For the frontend components that replace PA and LNA amplifier chains, implementation techniques for regenerative sampling circuits based on super-regenerative oscillators are presented. Finally, an analog-to-digital converter with outstanding performance and complete interfaces both to the analog baseband as well as to the digital side completes the set of building blocks for efficient ultra-high speed communication.

Ultra-high-speed imaging of the brain by the echo planar technique

International Nuclear Information System (INIS)

Worthington, B.S.; Stehling, M.K.; Ordidge, R.J.; Coxon, R.; Howseman, A.M.; Chapman, B.; Turner, R.; Firth, J.L.; Mansfield, P.

1988-01-01

Reduced examination time, greater patient tolerance and throughput, and the ability to study vascular and cerebrospinal fluid (CSF) flow phenomena are important advantages of ultra-high-speed brain imaging. The EPI derivatives BEST and MBEST create a complete 128 X 128-pixel image in 64 msec and 128 msec, respectively. In BEST images, T2 weighting is altered by adjusting the echo time, modulus BEST images have intrinsic T2 weighting. Repetition time alterations provide variable T1 weighting in both. Volunteer and patient studies illustrate how selective contrast manipulation allows excellent discrimination between gray and white matter and the brain and the CSF, enabling the demonstration of pathology

Analysis of the application of poly-nanocrystalline diamond tools for ultra precision machining of steel with ultrasonic assistance

Science.gov (United States)

Doetz, M.; Dambon, O.; Klocke, F.; Bulla, B.; Schottka, K.; Robertson, D. J.

2017-10-01

Ultra-precision diamond turning enables the manufacturing of parts with mirror-like surfaces and highest form accuracies out of non-ferrous, a few crystalline and plastic materials. Furthermore, an ultrasonic assistance has the ability to push these boundaries and enables the machining of materials like steel, which is not possible in a conventional way due to the excessive tool wear caused by the affinity of carbon to iron. Usually monocrystalline diamonds tools are applied due to their unsurpassed cutting edge properties. New cutting tool material developments have shown that it is possible to produce tools made of nano-polycrystalline diamonds with cutting edges equivalent to monocrystalline diamonds. In nano-polycrystalline diamonds ultra-fine grains of a few tens of nanometers are firmly and directly bonded together creating an unisotropic structure. The properties of this material are described to be isotropic, harder and tougher than those of the monocrystalline diamonds, which are unisotropic. This publication will present machining results from the newest investigations of the process potential of this new polycrystalline cutting material. In order to provide a baseline with which to characterize the cutting material cutting experiments on different conventional machinable materials like Cooper or Aluminum are performed. The results provide information on the roughness and the topography of the surface focusing on the comparison to the results while machining with monocrystalline diamond. Furthermore, the cutting material is tested in machining steel with ultrasonic assistance with a focus on tool life time and surface roughness. An outlook on the machinability of other materials will be given.

Mechanical-plowing-based high-speed patterning on hard material via advanced-control and ultrasonic probe vibration

Energy Technology Data Exchange (ETDEWEB)

Wang, Zhihua; Zou, Qingze, E-mail: qzzou@rci.rutgers.edu [Mechanical and Aerospace Engineering Department, Rutgers, the State University of New Jersey, Piscataway, New Jersey 08854 (United States); Tan, Jun; Jiang, Wei [Electrical and Computer Engineering Department, Rutgers, the State University of New Jersey, Piscataway, New Jersey 08854 (United States)

2013-11-15

In this paper, we present a high-speed direct pattern fabrication on hard materials (e.g., a tungsten-coated quartz substrate) via mechanical plowing. Compared to other probe-based nanolithography techniques based on chemical- and/or physical-reactions (e.g., the Dip-pen technique), mechanical plowing is meritorious for its low cost, ease of process control, and capability of working with a wide variety of materials beyond conductive and/or soft materials. However, direct patterning on hard material faces two daunting challenges. First, the patterning throughput is ultimately hindered by the “writing” (plowing) speed, which, in turn, is limited by the adverse effects that can be excited/induced during high-speed, and/or large-range plowing, including the vibrational dynamics of the actuation system (the piezoelectric actuator, the cantilever, and the mechanical fixture connecting the cantilever to the actuator), the dynamic cross-axis coupling between different axes of motion, and the hysteresis and the drift effects related to the piezoelectric actuators. Secondly, it is very challenging to directly pattern on ultra-hard materials via plowing. Even with a diamond probe, the line depth of the pattern via continuous plowing on ultra-hard materials such as tungsten, is still rather small (<0.5 nm), particularly when the “writing” speed becomes high. To overcome these two challenges, we propose to utilize a novel iterative learning control technique to achieve precision tracking of the desired pattern during high-speed, large-range plowing, and introduce ultrasonic vibration of the probe in the normal (vertical) direction during the plowing process to enable direct patterning on ultra hard materials. The proposed approach was implemented to directly fabricate patterns on a mask with tungsten coating and quartz substrate. The experimental results demonstrated that a large-size pattern of four grooves (20 μm in length with 300 nm spacing between lines) can be

Wear of ultra-high molecular weight polyethylene against damaged and undamaged stainless steel and diamond-like carbon-coated counterfaces.

Science.gov (United States)

Firkins, P; Hailey, J L; Fisher, J; Lettington, A H; Butter, R

1998-10-01

The wear of ultra-high molecular weight polyethylene (UHMWPE) in artificial joints and the resulting wear debris-induced osteolysis remains a major clinical concern in the orthopaedic sector. Third-body damage of metallic femoral heads is often cited as a cause of accelerated polyethylene wear, and the use of ceramic femoral heads in the hip is gaining increasing favour. In the knee prostheses and for smaller diameter femoral heads, the application of hard surface coatings, such as diamond-like carbon, is receiving considerable attention. However, to date, there has been little or no investigation of the tribology of these coatings in simulated biological environments. In this study, diamond-like carbon (DLC) has been compared to stainless steel in its undamaged form and following simulated third-body damage. The wear of UHMWPE was found to be similar when sliding against undamaged DLC and stainless steel counterfaces. DLC was found to be much more damage resistant than DLC. Under test conditions that simulate third-body damage to the femoral head, the wear of UHMWPE was seven times lower against DLC than against stainless steel (P < 0.05). The study shows DLC has considerable potential as a femoral bearing surface in artificial joints.

Ultra high speed framing photographs of laser produced plasmas using a picosecond optical shutter

International Nuclear Information System (INIS)

Gillman, G.B.; Ramsden, S.A.

1975-01-01

A study has been carried out of the spatial transmission properties of the optical Kerr effect shutter and it has been used to take ultra high speed framing photographs of laser produced plasmas in air and from solid targets. With a 1cm long CS 2 cell of aperture 5cm 2 a transmission of approximately 5% and an on/off contrast ratio of 10 4 was obtained. An image intensifier was necessary to obtain adequately exposed photographs of the plasma and the overall spatial resolution of the system was approximately 2μ. (author)

The clinical potential of ultra-high-speed echo-planar imaging

International Nuclear Information System (INIS)

Worthington, B.S.; Firth, J.L.; Morris, G.K.; Johnson, I.R.; Coxon, R.; Blamire, A.M.; Gibbs, P.; Mansfield, P.

1990-01-01

Ultra-high-speed echo-planar imaging (EPI) allows acquisition of a complete two-dimensional image in 64 to 128 ms devoid of movement artefact and without sacrifice of contrast due to relaxation time effects. In conventional whole-body MRI, however, obtrusive movement artefact and extended imaging time, resulting from the need to apply multiple sequences to facilitate lesion detection and pathological characterization, remain limitations. Reduced total examination time increases patient tolerance and throughput; furthermore optimization of contrast to achieve maximal conspicuity of particular features in liver or brain pathology is achieved simply and interactively by real time adjustment of the imaging parameters. The method provides the opportunity to study in real time dynamic events such as flow phenomena in the vascular and cerebrospinal fluid compartments of the brain as well as the kinetics of administered contrast agents. EPI is the only means of capturing the irregular motion of aperiodic cardiac events and bowel peristalsis. (author)

New insights into mechanisms of sonothrombolysis using ultra-high-speed imaging.

Science.gov (United States)

Chen, Xucai; Leeman, Jonathan E; Wang, Jianjun; Pacella, John J; Villanueva, Flordeliza S

2014-01-01

Thrombotic arterial occlusion is the principal etiology for acute cardiovascular syndromes such as stroke, myocardial infarction and unstable angina. Exposing the thrombus to ultrasound and microbubbles facilitates thrombus disruption, making "sonothrombolysis" a potentially powerful therapeutic strategy for thromboembolic diseases. However, optimization of such a strategy, and hence clinical translation, is constrained by an incomplete understanding of mechanisms by which ultrasound-induced microbubble vibrations disrupt blood clots. We posit that previously reported sonothrombolytic efficacy using inertial cavitation regimes was due, at least in part, to mechanical clot disruption by oscillating microbubbles. To test this hypothesis, we optically characterized lipid microbubble interactions with thrombus in the presence of ultrasound using a recently developed ultra-high-speed microscopy imaging system to visualize microbubble acoustic behaviors at megahertz frame rates. A microscope/acoustic stage designed for the system allowed an experimentally created thrombus and microbubbles to be insonified at a co-localized acoustic and optical focus during synchronized high-speed imaging. Under inertial cavitation conditions, large-amplitude microbubble oscillations caused thrombus deformation and pitting. Acoustic radiation forces (Bjerknes forces) further augmented microbubble-thrombus interaction. These observations suggest that a direct mechanical effect of oscillating lipid microbubbles on an adjacent thrombus may play a role in mediating clot disruption in the presence of specific ultrasound conditions. Copyright © 2014 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Advances in indirect detector systems for ultra high-speed hard X-ray imaging with synchrotron light

Science.gov (United States)

Olbinado, M. P.; Grenzer, J.; Pradel, P.; De Resseguier, T.; Vagovic, P.; Zdora, M.-C.; Guzenko, V. A.; David, C.; Rack, A.

2018-04-01

We report on indirect X-ray detector systems for various full-field, ultra high-speed X-ray imaging methodologies, such as X-ray phase-contrast radiography, diffraction topography, grating interferometry and speckle-based imaging performed at the hard X-ray imaging beamline ID19 of the European Synchrotron—ESRF. Our work highlights the versatility of indirect X-ray detectors to multiple goals such as single synchrotron pulse isolation, multiple-frame recording up to millions frames per second, high efficiency, and high spatial resolution. Besides the technical advancements, potential applications are briefly introduced and discussed.

Development of Dynamic Compaction Technology for Ultra High Strength Powder Products

International Nuclear Information System (INIS)

Rhee, Chang Kyu; Lee, M. K.; Uhm, Y. R.; Park, J. J.; Lee, J. G.; Ivanov, V. V.; Hong, S. J.

2007-04-01

A synthesis of ultra fine powder and its compaction have been considered as a new generation and high value added technology in various industrial fields such as automobile, machine tool, electronic chip, sensor and catalyst because of its special characteristics of high toughness, strength and wear resistance which are not shown in conventional process. In this study, ultra hard and fine powders, such as Fe-Si, CuNi and Al 2 O 3 , have been fabricated by the pulsed wire evaporation (PWE) method and mechanical alloying (MA) method. In addition, with ultra hard and fine powders, the magnetic core, diamond tool and water jet nozzle with high density were made by a uniaxial dynamic compaction for the purpose of the real industrial application

On the reduced-complexity of LDPC decoders for ultra-high-speed optical transmission.

Science.gov (United States)

Djordjevic, Ivan B; Xu, Lei; Wang, Ting

2010-10-25

We propose two reduced-complexity (RC) LDPC decoders, which can be used in combination with large-girth LDPC codes to enable ultra-high-speed serial optical transmission. We show that optimally attenuated RC min-sum sum algorithm performs only 0.46 dB (at BER of 10(-9)) worse than conventional sum-product algorithm, while having lower storage memory requirements and much lower latency. We further study the use of RC LDPC decoding algorithms in multilevel coded modulation with coherent detection and show that with RC decoding algorithms we can achieve the net coding gain larger than 11 dB at BERs below 10(-9).

Solutions for ultra-high speed optical wavelength conversion and clock recovery

DEFF Research Database (Denmark)

Oxenløwe, Leif Katsuo; Galili, Michael; Mulvad, Hans Christian Hansen

2006-01-01

This paper reports on our recent advances in ultra-fast optical communications relying on ultra-short pulses densely stacked in ultra-high bit rate serial data signals at a single wavelength. The paper describes details in solutions for the network functionalities of wavelength conversion and clock...... recovery at bit rates up to 320 Gb/s...

All-Optical Ultra-High-Speed OFDM to Nyquist-WDM Conversion Based on Complete Optical Fourier Transformation

DEFF Research Database (Denmark)

Guan, Pengyu; Røge, Kasper Meldgaard; Mulvad, Hans Christian Hansen

2016-01-01

We propose a novel all-optical ultra-high-speed orthogonal frequency-division multiplexing (OFDM) to Nyquist wavelength-division multiplexing (Nyquist-WDM) conversion scheme, achieved by exchanging the temporal and spectral profiles using a complete optical Fourier transformation (OFT). This scheme...... enables high-speed OFDM to Nyquist-WDM conversion without complex optical/electrical/optical conversion. The all-optical OFDM transmitter is based on the generation of OFDM symbols with a low duty cycle by rectangular temporal gating, which in combination with optical time-division multiplexing yields...... a higher symbol-rate OFDM signal. In the receiver, the converted Nyquist-WDM super-channel is WDM demultiplexed into individual Nyquist-WDM channels using a rectangular optical bandpass filter, followed by optical sampling at the intersymbol-interference free point. In the experimental demonstration...

Technics study on high accuracy crush dressing and sharpening of diamond grinding wheel

Science.gov (United States)

Jia, Yunhai; Lu, Xuejun; Li, Jiangang; Zhu, Lixin; Song, Yingjie

2011-05-01

Mechanical grinding of artificial diamond grinding wheel was traditional wheel dressing process. The rotate speed and infeed depth of tool wheel were main technics parameters. The suitable technics parameters of metals-bonded diamond grinding wheel and resin-bonded diamond grinding wheel high accuracy crush dressing were obtained by a mount of experiment in super-hard material wheel dressing grind machine and by analysis of grinding force. In the same time, the effect of machine sharpening and sprinkle granule sharpening was contrasted. These analyses and lots of experiments had extent instruction significance to artificial diamond grinding wheel accuracy crush dressing.

An Investigation to Determine if Higher Speeds are Obtained with the Diamond Jubilee Gregg Shorthand Method.

Science.gov (United States)

Starbuck, Ethel

The purpose of the study was to determine whether higher shorthand speeds were achieved by high school students in a 1-year shorthand course through the use of Simplified Gregg Shorthand or through the use of Diamond Jubilee (DJ) Gregg Shorthand. The control group consisted of 75 students enrolled in Simplified Shorthand during the years…

Design of rotating mirror for ultra-high speed camera based on dynamic characteristic

International Nuclear Information System (INIS)

Li Chunbo; Chai Jinlong; Liang Yexing; Liu Chunping; Wang Hongzhi; Yu Chunhui; Li Jingzhen; Huang Hongbin

2011-01-01

A systematic design method has been proposed for studying the dynamic design of rotating mirror for ultra-high speed camera. With the finite element software, the numerical analyses of static, modal, harmonic responses and natural frequency sensitivity for the preliminary-designed rotating mirror were done based on the static and dynamic theories. Some experiments were done to verify the results. The physical dimensions of the rotating mirror were modified repeatedly according to the results for designing a new rotating mirror. Then simulation and experiments of fatigue life for the new rotating mirror under alternating force were done. The results show that the maximum static stress is less than the yield stress of the rotating mirror material, which proves the new rotating mirror will not be subjected to static strength failure. However, the results of modal and harmonic response analyses indicate that the dynamic characteristic of the new rotating mirror can not meet the design requirement for the first critical speed is less than the service speed. In all the physical dimensions of the rotating mirror, the circum radius of mirror body and natural frequency are negatively correlated and the degree of correlation is maximal. The first-order natural frequency in- creases from 459.4 Hz to 713.6 Hz, the rate of change is 55.3%, the first critical speed is up to 42 816 r/min, avoiding resonance successfully, and the fatigue strength of the new rotating mirror can meet the design requirement. (authors)

Cold cathodes on ultra-dispersed diamond base

International Nuclear Information System (INIS)

Alimova, A.N.; Zhirnov, V.V.; Chubun, N.N.; Belobrov, P.I.

1998-01-01

Prospects of application of nano diamond powders for fabrication of cold cathodes are discussed.Cold cathodes based on silicon pointed structures with nano diamond coatings were prepared.The deposition technique of diamond coating was dielectrophoresis from suspension of nano diamond powder in organic liquids.The cathodes were tested in sealed prototypes of vacuum electronic devices

ULTRA-SHARP nonoscillatory convection schemes for high-speed steady multidimensional flow

Science.gov (United States)

Leonard, B. P.; Mokhtari, Simin

1990-01-01

For convection-dominated flows, classical second-order methods are notoriously oscillatory and often unstable. For this reason, many computational fluid dynamicists have adopted various forms of (inherently stable) first-order upwinding over the past few decades. Although it is now well known that first-order convection schemes suffer from serious inaccuracies attributable to artificial viscosity or numerical diffusion under high convection conditions, these methods continue to enjoy widespread popularity for numerical heat transfer calculations, apparently due to a perceived lack of viable high accuracy alternatives. But alternatives are available. For example, nonoscillatory methods used in gasdynamics, including currently popular TVD schemes, can be easily adapted to multidimensional incompressible flow and convective transport. This, in itself, would be a major advance for numerical convective heat transfer, for example. But, as is shown, second-order TVD schemes form only a small, overly restrictive, subclass of a much more universal, and extremely simple, nonoscillatory flux-limiting strategy which can be applied to convection schemes of arbitrarily high order accuracy, while requiring only a simple tridiagonal ADI line-solver, as used in the majority of general purpose iterative codes for incompressible flow and numerical heat transfer. The new universal limiter and associated solution procedures form the so-called ULTRA-SHARP alternative for high resolution nonoscillatory multidimensional steady state high speed convective modelling.

Next-generation technologies for spatial proteomics: Integrating ultra-high speed MALDI-TOF and high mass resolution MALDI FTICR imaging mass spectrometry for protein analysis.

Science.gov (United States)

Spraggins, Jeffrey M; Rizzo, David G; Moore, Jessica L; Noto, Michael J; Skaar, Eric P; Caprioli, Richard M

2016-06-01

MALDI imaging mass spectrometry is a powerful analytical tool enabling the visualization of biomolecules in tissue. However, there are unique challenges associated with protein imaging experiments including the need for higher spatial resolution capabilities, improved image acquisition rates, and better molecular specificity. Here we demonstrate the capabilities of ultra-high speed MALDI-TOF and high mass resolution MALDI FTICR IMS platforms as they relate to these challenges. High spatial resolution MALDI-TOF protein images of rat brain tissue and cystic fibrosis lung tissue were acquired at image acquisition rates >25 pixels/s. Structures as small as 50 μm were spatially resolved and proteins associated with host immune response were observed in cystic fibrosis lung tissue. Ultra-high speed MALDI-TOF enables unique applications including megapixel molecular imaging as demonstrated for lipid analysis of cystic fibrosis lung tissue. Additionally, imaging experiments using MALDI FTICR IMS were shown to produce data with high mass accuracy (z 5000) for proteins up to ∼20 kDa. Analysis of clear cell renal cell carcinoma using MALDI FTICR IMS identified specific proteins localized to healthy tissue regions, within the tumor, and also in areas of increased vascularization around the tumor. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Recognition of diamond grains on surface of fine diamond grinding wheel

Institute of Scientific and Technical Information of China (English)

Fengwei HUO; Zhuji JIN; Renke KANG; Dongming GUO; Chun YANG

2008-01-01

The accurate evaluation of grinding wheel sur-face topography, which is necessary for the investigation of the grinding principle, optimism, modeling, and simu-lation of a grinding process, significantly depends on the accurate recognition of abrasive grains from the measured wheel surface. A detailed analysis of the grain size distri-bution characteristics and grain profile wavelength of the fine diamond grinding wheel used for ultra-precision grinding is presented. The requirements of the spatial sampling interval and sampling area for instruments to measure the surface topography of a diamond grinding wheel are discussed. To recognize diamond grains, digital filtering is used to eliminate the high frequency disturb-ance from the measured 3D digital surface of the grinding wheel, the geometric features of diamond grains are then extracted from the filtered 3D digital surface, and a method based on the grain profile frequency characteris-tics, diamond grain curvature, and distance between two adjacent diamond grains is proposed. A 3D surface pro-filer based on scanning white light interferometry is used to measure the 3D surface topography of a #3000 mesh resin bonded diamond grinding wheel, and the diamond grains are then recognized from the 3D digital surface. The experimental result shows that the proposed method is reasonable and effective.

High-pressure-high-temperature treatment of natural diamonds

CERN Document Server

Royen, J V

2002-01-01

The results are reported of high-pressure-high-temperature (HPHT) treatment experiments on natural diamonds of different origins and with different impurity contents. The diamonds are annealed in a temperature range up to 2000 sup o C at stabilizing pressures up to 7 GPa. The evolution is studied of different defects in the diamond crystal lattice. The influence of substitutional nitrogen atoms, plastic deformation and the combination of these is discussed. Diamonds are characterized at room and liquid nitrogen temperature using UV-visible spectrophotometry, Fourier transform infrared spectrophotometry and photoluminescence spectrometry. The economic implications of diamond HPHT treatments are discussed.

Light volatiles in diamond: Physical interpretation and genetic significance

International Nuclear Information System (INIS)

Sellschop, J.P.F.; Madiba, C.C.P.; Annegarn, H.J.

1980-01-01

Natural diamond is characterised in terms of features in the infra-red and ultra-violet spectra. Additionally electron spin resonance, X-ray diffraction and topography, cathodoluminescence, mechanical and electrical measurements have been used to give more detail to such specification. It had been concluded that the major impurity in diamond was nitrogen and hence most physical phenomena have been interpreted as a manifestation of the mode(s) of occurence of nitrogen. From neutron activation analysis studies some 58 elements have been identified in diamond, many of course at trace levels. It has been shown that these data reveal a distinctive trace and minor element chemistry for diamond. Recently ion beam analyses have quantified the role of nitrogen in diamond characterisation. Most recently ion beam analysis has revealed that hydrogen, nitrogen and oxygen are all major impurities in diamond. Quantitative studies have been made using ( 19 Fe,α), (α,n) and ( 3 He,p) reactions. High temperature annealing in ultra-high vacuum conditions results in a substantial increase in the hydrogen measured as well as in the shape of the depth profile. Hydrogen is released from defect centres and diffuses rapidly through the diamond. Some of these hydrogen atoms are trapped at defect sites which are concentrated near surface as a result of the ion beam bombardement. A lesser response to the annealing treatment is found for oxygen and the smallest change for nitrogen. These ion beam data lend independent support to our earlier interpretation of the neutron activation data that all diamonds contain defects distributed fairly uniformly and consisting of sub-microscopic inclusions, the elemental composition of which suggests that each is a magma droplet from the upper mantle in which the diamond crystallized. The water-richness of the magma is an essential feature of the diamond genesis conditions. (orig.)

Ultrasonically Assisted Single Point Diamond Turning of Optical Mold of Tungsten Carbide

Directory of Open Access Journals (Sweden)

Zhanjie Li

2018-02-01

Full Text Available To realize high efficiency, low/no damage and high precision machining of tungsten carbide used for lens mold, a high frequency ultrasonic vibration cutting system was developed at first. Then, tungsten carbide was precisely machined with a polycrystalline diamond (PCD tool assisted by the self-developed high frequency ultrasonic vibration cutting system. Tool wear mechanism was investigated in ductile regime machining of tungsten carbide. The cutter back-off phenomenon in the process was analyzed. The subsequent experimental results of ultra-precision machining with a single crystal diamond tool showed that: under the condition of high frequency ultrasonic vibration cutting, nano-scale surface roughness can be obtained by the diamond tool with smaller tip radius and no defects like those of ground surface were found on the machined surface. Tool wear mechanisms of the single crystal diamond tool are mainly abrasive wear and micro-chipping. To solve the problem, a method of inclined ultrasonic vibration cutting with negative rake angle was put forward according to force analysis, which can further reduce tool wear and roughness of the machined surface. The investigation was important to high efficiency and quality ultra-precision machining of tungsten carbide.

Development of ultra high speed photographic system using high repetition rate visible laser

International Nuclear Information System (INIS)

Lee, Jong Min; Cha, Byung Hun; Kim, Sung Ho; Kim, Jung Bog; Lim, Chang Hwan; Cha, Hyung Ki; Song, Kyu Seok; Lee, Byung Deok; Rhi, Jong Hoon; Baik, Dae Hyun; Han, Jae Min; Rho, Si Pyo; Lee, Byung Cheol; Jeong, Do Yung; Choi, An Seong; Jeong, Chan Ik; Park, Dae Ung; Jeong, Sung Min; Lee, Sang Kil; Kim, Heon Jun; Jang, Rae gak; Jo, Do Hun; Park, Min Young

1992-12-01

The goal of this project is to develop and commercialize a high speed photographic system equipped with a high repetition rate visible laser. The developed system provides the characteristics of high time resolution and large number of frames. The system consists of 10 W air cooled CVL or a 30 W water cooled CVL, a rotating drum-type high speed camera with the framing rate of 35,000 fps, and a automatic control device. The system has the performance of 10 nsec time resolution, 35,000 fps framing rate, and 250 picture frames. The high speed photographic systems are widely applied to the fields such as high-efficient engine development, high-speed vibration analysis, shock wave propagation study, flow visualization analysis, weapon development, etc. (Author)

Ultra high-speed x-ray imaging of laser-driven shock compression using synchrotron light

Science.gov (United States)

Olbinado, Margie P.; Cantelli, Valentina; Mathon, Olivier; Pascarelli, Sakura; Grenzer, Joerg; Pelka, Alexander; Roedel, Melanie; Prencipe, Irene; Laso Garcia, Alejandro; Helbig, Uwe; Kraus, Dominik; Schramm, Ulrich; Cowan, Tom; Scheel, Mario; Pradel, Pierre; De Resseguier, Thibaut; Rack, Alexander

2018-02-01

A high-power, nanosecond pulsed laser impacting the surface of a material can generate an ablation plasma that drives a shock wave into it; while in situ x-ray imaging can provide a time-resolved probe of the shock-induced material behaviour on macroscopic length scales. Here, we report on an investigation into laser-driven shock compression of a polyurethane foam and a graphite rod by means of single-pulse synchrotron x-ray phase-contrast imaging with MHz frame rate. A 6 J, 10 ns pulsed laser was used to generate shock compression. Physical processes governing the laser-induced dynamic response such as elastic compression, compaction, pore collapse, fracture, and fragmentation have been imaged; and the advantage of exploiting the partial spatial coherence of a synchrotron source for studying low-density, carbon-based materials is emphasized. The successful combination of a high-energy laser and ultra high-speed x-ray imaging using synchrotron light demonstrates the potentiality of accessing complementary information from scientific studies of laser-driven shock compression.

Twinning of cubic diamond explains reported nanodiamond polymorphs

Science.gov (United States)

Németh, Péter; Garvie, Laurence A. J.; Buseck, Peter R.

2015-12-01

The unusual physical properties and formation conditions attributed to h-, i-, m-, and n-nanodiamond polymorphs has resulted in their receiving much attention in the materials and planetary science literature. Their identification is based on diffraction features that are absent in ordinary cubic (c-) diamond (space group: Fd-3m). We show, using ultra-high-resolution transmission electron microscope (HRTEM) images of natural and synthetic nanodiamonds, that the diffraction features attributed to the reported polymorphs are consistent with c-diamond containing abundant defects. Combinations of {113} reflection and rotation twins produce HRTEM images and d-spacings that match those attributed to h-, i-, and m-diamond. The diagnostic features of n-diamond in TEM images can arise from thickness effects of c-diamonds. Our data and interpretations strongly suggest that the reported nanodiamond polymorphs are in fact twinned c-diamond. We also report a new type of twin ( rotational), which can give rise to grains with dodecagonal symmetry. Our results show that twins are widespread in diamond nanocrystals. A high density of twins could strongly influence their applications.

Twinning of cubic diamond explains reported nanodiamond polymorphs.

Science.gov (United States)

Németh, Péter; Garvie, Laurence A J; Buseck, Peter R

2015-12-16

The unusual physical properties and formation conditions attributed to h-, i-, m-, and n-nanodiamond polymorphs has resulted in their receiving much attention in the materials and planetary science literature. Their identification is based on diffraction features that are absent in ordinary cubic (c-) diamond (space group: Fd-3m). We show, using ultra-high-resolution transmission electron microscope (HRTEM) images of natural and synthetic nanodiamonds, that the diffraction features attributed to the reported polymorphs are consistent with c-diamond containing abundant defects. Combinations of {113} reflection and rotation twins produce HRTEM images and d-spacings that match those attributed to h-, i-, and m-diamond. The diagnostic features of n-diamond in TEM images can arise from thickness effects of c-diamonds. Our data and interpretations strongly suggest that the reported nanodiamond polymorphs are in fact twinned c-diamond. We also report a new type of twin ( rotational), which can give rise to grains with dodecagonal symmetry. Our results show that twins are widespread in diamond nanocrystals. A high density of twins could strongly influence their applications.

Sound speed and thermal property measurements of inert materials: laser spectroscopy and the diamond-anvil cell

Energy Technology Data Exchange (ETDEWEB)

Zaug, J.M.

1997-07-01

An indispensable companion to dynamical physics experimentation, static high-pressure diamond-anvil cell research continues to evolve, with laser diagnostic, as an accurate and versatile experimental deep planetary properties have bootstrapped each other in a process that has produced even higher pressures; consistently improved calibrations of temperature and pressure under static and dynamic conditions; and unprecedented data and understanding of materials, their elasticity, equations of state (EOS), and transport properties under extreme conditions. A collection of recent pressure and/or temperature dependent acoustic and thermal measurements and deduced mechanical properties and EOS data are summarized for a wide range of materials including H2, H2O, H2S, D2S, CO2, CH4, N2O, CH3OH,, SiO2, synthetic lubricants, PMMA, single crystal silicates, and ceramic superconductors. Room P&T sound speed measurements are presented for the first time on single crystals of beta-HMX. New high-pressure and temperature diamond cell designed and pressure calibrant materials are reviewed.

Surface roughness when diamond turning RSA 905 optical aluminium

Science.gov (United States)

Otieno, T.; Abou-El-Hossein, K.; Hsu, W. Y.; Cheng, Y. C.; Mkoko, Z.

2015-08-01

Ultra-high precision machining is used intensively in the photonics industry for the production of various optical components. Aluminium alloys have proven to be advantageous and are most commonly used over other materials to make various optical components. Recently, the increasing demand from optical systems for optical aluminium with consistent material properties has led to the development of newly modified grades of aluminium alloys produced by rapid solidification in the foundry process. These new aluminium grades are characterised by their finer microstructures and refined mechanical and physical properties. However the machining database of these new optical aluminium grades is limited and more research is still required to investigate their machinability performance when they are diamond turned in ultrahigh precision manufacturing environment. This work investigates the machinability of rapidly solidified aluminium RSA 905 by varying a number of diamond-turning cutting parameters and measuring the surface roughness over a cutting distance of 4 km. The machining parameters varied in this study were the cutting speed, feed rate and depth of cut. The results showed a common trend of decrease in surface roughness with increasing cutting distance. The lowest surface roughness Ra result obtained after 4 km in this study was 3.2 nm. This roughness values was achieved using a cutting speed of 1750 rpm, feed rate of 5 mm/min and depth of cut equal to 25 μm.

Dynamic ultra high speed Scheimpflug imaging for assessing corneal biomechanical properties

Directory of Open Access Journals (Sweden)

Renato Ambrósio Jr

2013-04-01

Full Text Available OBJECTIVE: To describe a novel technique for clinical characterization of corneal biomechanics using non-invasive dynamic imaging. METHODS: Corneal deformation response during non contact tonometry (NCT is monitored by ultra-high-speed (UHS photography. The Oculus Corvis ST (Scheimpflug Technology; Wetzlar, Germany has a UHS Scheimpflug camera, taking over 4,300 frames per second and of a single 8mm horizontal slit, for monitoring corneal deformation response to NCT. The metered collimated air pulse or puff has a symmetrical configuration and fixed maximal internal pump pressure of 25 kPa. The bidirectional movement of the cornea in response to the air puff is monitored. RESULTS: Measurement time is 30ms, with 140 frames acquired. Advanced algorithms for edge detection of the front and back corneal contours are applied for every frame. IOP is calculated based on the first applanation moment. Deformation amplitude (DA is determined as the highest displacement of the apex in the highest concavity (HC moment. Applanation length (AL and corneal velocity (CVel are recorded during ingoing and outgoing phases. CONCLUSION: Corneal deformation can be monitored during non contact tonometry. The parameters generated provide clinical in vivo characterization of corneal biomechanical properties in two dimensions, which is relevant for different applications in Ophthalmology.

Method and article of manufacture corresponding to a composite comprised of ultra nonacrystalline diamond, metal, and other nanocarbons useful for thermoelectric and other applications

Science.gov (United States)

Gruen, Dieter M.

2010-05-18

One provides (101) disperse ultra-nanocrystalline diamond powder material that comprises a plurality of substantially ordered crystallites that are each sized no larger than about 10 nanometers. One then reacts (102) these crystallites with a metallic component. The resultant nanowire is then able to exhibit a desired increase with respect to its ability to conduct electricity while also substantially preserving the thermal conductivity behavior of the disperse ultra-nanocrystalline diamond powder material. The reaction process can comprise combining (201) the crystallites with one or more metal salts in an aqueous solution and then heating (203) that aqueous solution to remove the water. This heating can occur in a reducing atmosphere (comprising, for example, hydrogen and/or methane) to also reduce the salt to metal.

Reactive Burn Model Calibration for PETN Using Ultra-High-Speed Phase Contrast Imaging

Science.gov (United States)

Johnson, Carl; Ramos, Kyle; Bolme, Cindy; Sanchez, Nathaniel; Barber, John; Montgomery, David

2017-06-01

A 1D reactive burn model (RBM) calibration for a plastic bonded high explosive (HE) requires run-to-detonation data. In PETN (pentaerythritol tetranitrate, 1.65 g/cc) the shock to detonation transition (SDT) is on the order of a few millimeters. This rapid SDT imposes experimental length scales that preclude application of traditional calibration methods such as embedded electromagnetic gauge methods (EEGM) which are very effective when used to study 10 - 20 mm thick HE specimens. In recent work at Argonne National Laboratory's Advanced Photon Source we have obtained run-to-detonation data in PETN using ultra-high-speed dynamic phase contrast imaging (PCI). A reactive burn model calibration valid for 1D shock waves is obtained using density profiles spanning the transition to detonation as opposed to particle velocity profiles from EEGM. Particle swarm optimization (PSO) methods were used to operate the LANL hydrocode FLAG iteratively to refine SURF RBM parameters until a suitable parameter set attained. These methods will be presented along with model validation simulations. The novel method described is generally applicable to `sensitive' energetic materials particularly those with areal densities amenable to radiography.

Radiation-Induced Damage and Recovery of Ultra-Nanocrystalline Diamond: Toward Applications in Harsh Environments.

Science.gov (United States)

Martin, Aiden A; Filevich, Jorge; Straw, Marcus; Randolph, Steven; Botman, Aurélien; Aharonovich, Igor; Toth, Milos

2017-11-15

Ultra-nanocrystalline diamond (UNCD) is increasingly being used in the fabrication of devices and coatings due to its excellent tribological properties, corrosion resistance, and biocompatibility. Here, we study its response to irradiation with kiloelectronvolt electrons as a controlled model for extreme ionizing environments. Real time Raman spectroscopy reveals that the radiation-damage mechanism entails dehydrogenation of UNCD grain boundaries, and we show that the damage can be recovered by annealing at 883 K. Our results have significant practical implications for the implementation of UNCD in extreme environment applications, and indicate that the films can be used as radiation sensors.

High speed motion-picture photography. Instrumentation and application

International Nuclear Information System (INIS)

Bertin-Maghit, G.; Delli, C.; Falgayrettes, M.

1981-01-01

Filming technology at 5,000 frames/second is presented in this paper for the determination of the volume and the expension speed of a gas bubble in water. The high speed 16 mm movie camera, fitted with ultra-wide angle lenses, is placed in front of a side light facing the bubble. Ten 60 ms fast flashes, released in succession, illuminate the bubble [fr

Ultra-fast calculations using diamond

NARCIS (Netherlands)

Van Dijk, T.

2011-01-01

TU Delft researchers have managed to use a piece of diamond to hold four quantum bits that can be spun, flipped and entangled with each other. This is an important step towards a working quantum computer

Characterising argon-bomb balloons for high-speed photography

CSIR Research Space (South Africa)

Olivier, M

2013-08-01

Full Text Available A method to optimise the geometry, explosive charge mass and volume of an argon bomb for specific lighting requirements has been proposed. The method is specifically aimed at applications that require photographic diagnostics with ultra-high speed...

Anisotropic diamond etching through thermochemical reaction between Ni and diamond in high-temperature water vapour.

Science.gov (United States)

Nagai, Masatsugu; Nakanishi, Kazuhiro; Takahashi, Hiraku; Kato, Hiromitsu; Makino, Toshiharu; Yamasaki, Satoshi; Matsumoto, Tsubasa; Inokuma, Takao; Tokuda, Norio

2018-04-27

Diamond possesses excellent physical and electronic properties, and thus various applications that use diamond are under development. Additionally, the control of diamond geometry by etching technique is essential for such applications. However, conventional wet processes used for etching other materials are ineffective for diamond. Moreover, plasma processes currently employed for diamond etching are not selective, and plasma-induced damage to diamond deteriorates the device-performances. Here, we report a non-plasma etching process for single crystal diamond using thermochemical reaction between Ni and diamond in high-temperature water vapour. Diamond under Ni films was selectively etched, with no etching at other locations. A diamond-etching rate of approximately 8.7 μm/min (1000 °C) was successfully achieved. To the best of our knowledge, this rate is considerably greater than those reported so far for other diamond-etching processes, including plasma processes. The anisotropy observed for this diamond etching was considerably similar to that observed for Si etching using KOH.

A wear simulation study of nanostructured CVD diamond-on-diamond articulation involving concave/convex mating surfaces

Science.gov (United States)

Baker, Paul A.; Thompson, Raymond G.; Catledge, Shane A.

2015-01-01

Using microwave-plasma Chemical Vapor Deposition (CVD), a 3-micron thick nanostructured-diamond (NSD) layer was deposited onto polished, convex and concave components that were machined from Ti-6Al-4V alloy. These components had the same radius of curvature, 25.4mm. Wear testing of the surfaces was performed by rotating articulation of the diamond-deposited surfaces (diamond-on-diamond) with a load of 225N for a total of 5 million cycles in bovine serum resulting in polishing of the diamond surface and formation of very shallow, linear wear grooves of less than 50nm depth. The two diamond surfaces remained adhered to the components and polished each other to an average surface roughness that was reduced by as much as a factor of 80 for the most polished region located at the center of the condyle. Imaging of the surfaces showed that the initial wearing-in phase of diamond was only beginning at the end of the 5 million cycles. Atomic force microscopy, scanning electron microscopy, Raman spectroscopy, and surface profilometry were used to characterize the surfaces and verify that the diamond remained intact and uniform over the surface, thereby protecting the underlying metal. These wear simulation results show that diamond deposition on Ti alloy has potential application for joint replacement devices with improved longevity over existing devices made of cobalt chrome and ultra-high molecular weight polyethylene (UHMWPE). PMID:26989457

System Design of a Cheetah Robot Toward Ultra-high Speed

OpenAIRE

Mantian Li; Xin Wang; Wei Guo; Pengfei Wang; Lining Sun

2014-01-01

High-speed legged locomotion pushes the limits of the most challenging problems of design and development of the mechanism, also the control and the perception method. The cheetah is an existence proof of concept of what we imitate for high-speed running, and provides us lots of inspiration on design. In this paper, a new model of a cheetah-like robot is developed using anatomical analysis and design. Inspired by a biological neural mechanism, we propose a novel control method for controlling...

Natural occurrence of pure nano-polycrystalline diamond from impact crater

Science.gov (United States)

Ohfuji, Hiroaki; Irifune, Tetsuo; Litasov, Konstantin D.; Yamashita, Tomoharu; Isobe, Futoshi; Afanasiev, Valentin P.; Pokhilenko, Nikolai P.

2015-10-01

Consolidated bodies of polycrystalline diamond with grain sizes less than 100 nm, nano-polycrystalline diamond (NPD), has been experimentally produced by direct conversion of graphite at high pressure and high temperature. NPD has superior hardness, toughness and wear resistance to single-crystalline diamonds because of its peculiar nano-textures, and has been successfully used for industrial and scientific applications. Such sintered nanodiamonds have, however, not been found in natural mantle diamonds. Here we identified natural pure NPD, which was produced by a large meteoritic impact about 35 Ma ago in Russia. The impact diamonds consist of well-sintered equigranular nanocrystals (5-50 nm), similar to synthetic NPD, but with distinct [111] preferred orientation. They formed through the martensitic transformation from single-crystal graphite. Stress-induced local fragmentation of the source graphite and subsequent rapid transformation to diamond in the limited time scale result in multiple diamond nucleation and suppression of the overall grain growth, producing the unique nanocrystalline texture of natural NPD. A huge amount of natural NPD is expected to be present in the Popigai crater, which is potentially important for applications as novel ultra-hard material.

Advanced Modular, Multi-Channel, High Speed Fiber Optic Sensing System for Acoustic Emissions Monitoring, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Intelligent Fiber Optic Systems Corporation (IFOS) proposes to prove the feasibility of innovations based on ultra-light-weight, ultra-high-speed, multi-channel,...

Defects of diamond single crystal grown under high temperature and high pressure

Energy Technology Data Exchange (ETDEWEB)

Su, Qingcai, E-mail: suqc@sdu.edu.cn [Key Laboratory of Liquid Structure and Heredity of Materials (Ministry of Education), Shandong University, Jinan, P. R. China, 250061 (China); School of Materials Science and Engineering, Shandong University, Jinan, P. R. China, 250061 (China); Shandong Engineering Research Center for Superhard Materials, Zoucheng, P. R. China 273500 (China); Zhang, Jianhua [School of Mechanical Engineering, Shandong University, Jinan, P. R. China, 250061 (China); Li, Musen [Key Laboratory of Liquid Structure and Heredity of Materials (Ministry of Education), Shandong University, Jinan, P. R. China, 250061 (China); School of Materials Science and Engineering, Shandong University, Jinan, P. R. China, 250061 (China); Shandong Engineering Research Center for Superhard Materials, Zoucheng, P. R. China 273500 (China)

2013-11-01

The diamond single crystal, synthesized with Fe–Ni–C–B system of catalyst under high temperature and high pressure, had been observed by field emission scanning electron microscope and transmission electron microscope. The presence of a cellular structure suggested that the diamond grew from melted catalyst solution and there existed a zone of component supercooling zone in front of the solid–liquid interface. The main impurities in the diamond crystal was (FeNi){sub 23}C{sub 6}. The triangle screw pit revealed on the (111) plane was generated by the screw dislocation meeting the diamond (111) plane at the points of emergence of dislocations. A narrow twin plane was formed between the two (111) plane. - Highlights: • High pressure, high temperature synthesis of diamond single crystal. • Fe–Ni–C–B used as catalyst, graphite as carbon source. • The main impurity in the diamond crystal was (FeNi){sub 23}C{sub 6}. • Surface defects arose from screw dislocations and stacking faults.

Optical studies of high quality synthetic diamond

International Nuclear Information System (INIS)

Sharp, S.J.

1999-01-01

This thesis is concerned with the study of fundamental and defect induced optical properties of synthetic diamond grown using high pressure, high temperature (HPHT) synthesis or chemical vapour deposition (CVD). The primary technique used for investigation is cathodoluminescence (including imaging and decay-time measurements) in addition to other forms of optical spectroscopy. This thesis is timely in that the crystallinity and purity of synthetic diamond has increased ten fold over the last few years. The diamond exciton emission, which is easily quenched by the presence of defects, is studied in high quality samples in detail. In addition the ability now exists to engineer the isotopic content of synthetic diamond to a high degree of accuracy. The experimental chapters are divided as follows: Chapter 2: High resolution, low temperature spectra reveal a splitting of the free-exciton phonon recombination emission peaks and the bound-exciton zero phonon line. Included are measurements of the variation in intensity and decay-time as a function of temperature. Chapter 3: The shift in energy of the phonon-assisted free-exciton phonon replicas with isotopic content has been measured. The shift is in agreement with the results of interatomic force model for phonon scattering due to isotope disorder. Chapter 4: A study of the shift in energy with isotopic content of the diamond of the GR1 band due to the neutral vacancy has allowed a verification of the theoretical predictions due to the Jahn Teller effect. Chapter 5: The spatial distribution of the free-exciton luminescence is studied in HPHT synthetic and CVD diamond. A variation in intensity with distance from the surface is interpreted as a significant non-radiative loss of excitons to the surface. Chapter 6: The decay-times of all known self-interstitial related centres have been measured in order to calculate the concentration of these centres present in electron irradiated diamond. (author)

High vacuum tribology of polycrystalline diamond coatings

Indian Academy of Sciences (India)

Polycrystalline diamond coatings; hot filament CVD; high vacuum tribology. 1. Introduction .... is a characteristic of graphite. We mark the (diamond ... coefficient of friction due to changes in substrate temperature. The average coefficient of.

Bone repair after osteotomy with diamond burs and CVD ultrasonic tips – histological study in rats

OpenAIRE

Matuda, Fábio S.; Pagani, Clovis; Miranda, Carolina B.; Crema, Aline A. S.; Brentel, Aline S.; Carvalho, Yasmin R.

2010-01-01

This study histologically evaluated the behavior of bone tissue of rats submitted to osteotomy with conventional diamond burs in high speed and a new ultrasonic diamond tips system (CVD – Chemical Vapor Deposition), at different study periods. The study was conducted on 24 Wistar rats. Osteotomy was performed on the posterior paws of each rat, with utilization of diamond burs in high speed under thorough water cooling at the right paw, and CVD tips at the left paw. Animals were killed a...

Diamond sensors for future high energy experiments

Energy Technology Data Exchange (ETDEWEB)

Bachmair, Felix, E-mail: bachmair@phys.ethz.ch

2016-09-21

With the planned upgrade of the LHC to High-Luminosity-LHC [1], the general purpose experiments ATLAS and CMS are planning to upgrade their innermost tracking layers with more radiation tolerant technologies. Chemical Vapor Deposition CVD diamond is one such technology. CVD diamond sensors are an established technology as beam condition monitors in the highest radiation areas of all LHC experiments. The RD42-collaboration at CERN is leading the effort to use CVD diamond as a material for tracking detectors operating in extreme radiation environments. An overview of the latest developments from RD42 is presented including the present status of diamond sensor production, a study of pulse height dependencies on incident particle flux and the development of 3D diamond sensors.

Diamond particle detectors systems in high energy physics

CERN Document Server

Gan, Kock Kiam

2015-01-01

The measurement of luminosity at the Large Hadron Collider (LHC) using diamond detect or s has matured from devices based on a rather large pads to highly granular pixelated device s . The ATLAS experiment has recently installed a diamond pixel detector, the Diamond Beam Monitor (DBM), to measure the luminosity in the upgraded LHC with higher instantaneous luminosity. Polycrystalline diamonds were used to fabricate the diamond pixel modules. The design , production, and test beam result s are described. CMS also has a similar plan to construct a diamond based luminosity monitor, the Pixel Luminos ity Telescope s (PLT) . In a pilot run using single crystal diamond, the pulse height was found to depend on the luminosity . Consequently the collaboration decided to use silicon instead due to time constrain ts .

A digital calibration technique for an ultra high-speed wide-bandwidth folding and interpolating analog-to-digital converter in 0.18-{mu}m CMOS technology

Energy Technology Data Exchange (ETDEWEB)

Yu Jinshan; Zhang Ruitao; Zhang Zhengping; Wang Yonglu; Zhu Can; Zhang Lei; Yu Zhou; Han Yong, E-mail: yujinshan@yeah.net [National Laboratory of Analog IC' s, Chongqing 400060 (China)

2011-01-15

A digital calibration technique for an ultra high-speed folding and interpolating analog-to-digital converter in 0.18-{mu}m CMOS technology is presented. The similar digital calibration techniques are taken for high 3-bit flash converter and low 5-bit folding and interpolating converter, which are based on well-designed calibration reference, calibration DAC and comparators. The spice simulation and the measured results show the ADC produces 5.9 ENOB with calibration disabled and 7.2 ENOB with calibration enabled for high-frequency wide-bandwidth analog input. (semiconductor integrated circuits)

Comparison of Finite Element Modeling and Experimental Pressure Distribution in a Diamond Anvil Cell

Science.gov (United States)

Kondrat'yev, Andreiy I.; Murphy, Michael J.; Weir, Samuel T.; Vohra, Yogesh K.

2002-10-01

Ultra high pressures can be obtained in a Diamond Anvil Cell (DAC) device by optimizing the geometrical shape of diamond anvil and by use of high strength gasket materials. Radial pressure distribution in a diamond-coated rhenium gasket was measured by the micro-collimated X-ray diffraction techniques at NSLS, Brookhaven National Laboratory up to peak pressure of 220 GPa. The process of DAC compression was described by finite element analysis using NIKE-2D software. The mechanical properties of the diamond-coated gasket material were modeled and radial pressure distribution obtained was in good agreement with the experimental data. The calculated shear stress in diamond in the axial direction was shown to depend strongly on the yield strength of the gasket material and may limit the ultimate pressure that can be obtained with the use of high strength gasket materials. Supported by the National Science Foundation (NSF) Grant No. DMR-0203779.

High Heat Load Diamond Monochromator Project at ESRF

International Nuclear Information System (INIS)

Van aerenbergh, P.; Detlefs, C.; Haertwig, J.; Lafford, T. A.; Masiello, F.; Roth, T.; Schmid, W.; Wattecamps, P.; Zhang, L.

2010-01-01

Due to its outstanding thermal properties, diamond is an attractive alternative to silicon as a monochromator material for high intensity X-ray beams. To date, however, the practical applications have been limited by the small size and relatively poor crystallographic quality of the crystals available. The ESRF Diamond Project Group has studied the perfection of diamonds in collaboration with industry and universities. The group has also designed and tested different stress-free mounting techniques to integrate small diamonds into larger X-ray optical elements. We now propose to develop a water-cooled Bragg-Bragg double crystal monochromator using diamond (111) crystals. It will be installed on the ESRF undulator beamline, ID06, for testing under high heat load. This monochromator will be best suited for the low energy range, typically from ∼3.4 keV to 15 keV, due to the small size of the diamonds available and the size of the beam footprint. This paper presents stress-free mounting techniques studied using X-ray diffraction imaging, and their thermal-mechanical analysis by finite element modelling, as well as the status of the ID06 monochromator project.

Diamond detectors for high energy physics experiments

Science.gov (United States)

Bäni, L.; Alexopoulos, A.; Artuso, M.; Bachmair, F.; Bartosik, M.; Beacham, J.; Beck, H.; Bellini, V.; Belyaev, V.; Bentele, B.; Berdermann, E.; Bergonzo, P.; Bes, A.; Brom, J.-M.; Bruzzi, M.; Cerv, M.; Chiodini, G.; Chren, D.; Cindro, V.; Claus, G.; Collot, J.; Cumalat, J.; Dabrowski, A.; D'Alessandro, R.; Dauvergne, D.; de Boer, W.; Dorfer, C.; Dünser, M.; Eremin, V.; Eusebi, R.; Forcolin, G.; Forneris, J.; Frais-Kölbl, H.; Gallin-Martel, L.; Gallin-Martel, M. L.; Gan, K. K.; Gastal, M.; Giroletti, C.; Goffe, M.; Goldstein, J.; Golubev, A.; Gorišek, A.; Grigoriev, E.; Grosse-Knetter, J.; Grummer, A.; Gui, B.; Guthoff, M.; Haughton, I.; Hiti, B.; Hits, D.; Hoeferkamp, M.; Hofmann, T.; Hosslet, J.; Hostachy, J.-Y.; Hügging, F.; Hutton, C.; Jansen, H.; Janssen, J.; Kagan, H.; Kanxheri, K.; Kasieczka, G.; Kass, R.; Kassel, F.; Kis, M.; Konovalov, V.; Kramberger, G.; Kuleshov, S.; Lacoste, A.; Lagomarsino, S.; Lo Giudice, A.; Lukosi, E.; Maazouzi, C.; Mandic, I.; Mathieu, C.; Menichelli, M.; Mikuž, M.; Morozzi, A.; Moss, J.; Mountain, R.; Murphy, S.; Muškinja, M.; Oh, A.; Oliviero, P.; Passeri, D.; Pernegger, H.; Perrino, R.; Picollo, F.; Pomorski, M.; Potenza, R.; Quadt, A.; Re, A.; Reichmann, M.; Riley, G.; Roe, S.; Sanz, D.; Scaringella, M.; Schaefer, D.; Schmidt, C. J.; Schnetzer, S.; Sciortino, S.; Scorzoni, A.; Seidel, S.; Servoli, L.; Smith, S.; Sopko, B.; Sopko, V.; Spagnolo, S.; Spanier, S.; Stenson, K.; Stone, R.; Sutera, C.; Tannenwald, B.; Taylor, A.; Traeger, M.; Tromson, D.; Trischuk, W.; Tuve, C.; Uplegger, L.; Velthuis, J.; Venturi, N.; Vittone, E.; Wagner, S.; Wallny, R.; Wang, J. C.; Weingarten, J.; Weiss, C.; Wengler, T.; Wermes, N.; Yamouni, M.; Zavrtanik, M.

2018-01-01

Beam test results of the radiation tolerance study of chemical vapour deposition (CVD) diamond against different particle species and energies is presented. We also present beam test results on the independence of signal size on incident particle rate in charged particle detectors based on un-irradiated and irradiated poly-crystalline CVD diamond over a range of particle fluxes from 2 kHz/cm2 to 10 MHz/cm2. The pulse height of the sensors was measured with readout electronics with a peaking time of 6 ns. In addition functionality of poly-crystalline CVD diamond 3D devices was demonstrated in beam tests and 3D diamond detectors are shown to be a promising technology for applications in future high luminosity experiments.

NEW HIGH STRENGTH AND FASTER DRILLING TSP DIAMOND CUTTERS

Energy Technology Data Exchange (ETDEWEB)

Robert Radtke

2006-01-31

The manufacture of thermally stable diamond (TSP) cutters for drill bits used in petroleum drilling requires the brazing of two dissimilar materials--TSP diamond and tungsten carbide. The ENDURUS{trademark} thermally stable diamond cutter developed by Technology International, Inc. exhibits (1) high attachment (shear) strength, exceeding 345 MPa (50,000 psi), (2) TSP diamond impact strength increased by 36%, (3) prevents TSP fracture when drilling hard rock, and (4) maintains a sharp edge when drilling hard and abrasive rock. A novel microwave brazing (MWB) method for joining dissimilar materials has been developed. A conventional braze filler metal is combined with microwave heating which minimizes thermal residual stress between materials with dissimilar coefficients of thermal expansion. The process results in preferential heating of the lower thermal expansion diamond material, thus providing the ability to match the thermal expansion of the dissimilar material pair. Methods for brazing with both conventional and exothermic braze filler metals have been developed. Finite element modeling (FEM) assisted in the fabrication of TSP cutters controllable thermal residual stress and high shear attachment strength. Further, a unique cutter design for absorbing shock, the densification of otherwise porous TSP diamond for increased mechanical strength, and diamond ion implantation for increased diamond fracture resistance resulted in successful drill bit tests.

Cleaving the Halqeh-ye-nur diamonds: a dynamic fracture analysis.

Science.gov (United States)

Atkinson, Colin; Martineau, Philip M; Khan, Rizwan U A; Field, John E; Fisher, David; Davies, Nick M; Samartseva, Julia V; Putterman, Seth J; Hird, Jonathan R

2015-03-28

The degree of surface roughness and clarity with which a surface in a brittle material can be formed via fracture is known to be related to the speed of the propagating crack. Cracks traversing a brittle material at low speed produce very smooth surfaces, while those propagating faster create less reflective and rough surfaces (Buehler MJ, Gao H. 2006 Nature 439, 307-310 (doi:10.1038/nature04408)). The elastic wave speeds (c(l)≈18 000 m s(-1), c(s)≈11 750 m s(-1)) in diamond are fast (Willmott GR, Field JE. 2006 Phil. Mag. 86, 4305-4318 (doi:10.1080/14786430500482336)) and present a particular problem in creating smooth surfaces during the cleaving of diamond-a routine operation in the fashioning of diamonds for gemstone purposes--as the waves are reflected from the boundaries of the material and can add a tensile component to the propagating crack tip causing the well-known cleavage steps observed on diamond surfaces (Field JE. 1971 Contemp. Phys. 12, 1-31 (doi:10.1080/00107517108205103); Field JE. 1979 Properties of diamond, 1st edn, Academic Press; Wilks EM. 1958 Phil. Mag. 3, 1074-1080 (doi:10.1080/14786435808237036)). Here we report an analysis of two diamonds, having large dimensions and high aspect ratio, which from a gemological analysis are shown to have been cleaved from the same 200 carat specimen. A methodology for their manufacture is calculated by an analysis of a model problem. This takes into account the effect of multiple reflections from the sample boundaries. It is suggested that the lapidary had an intuitive guide to how to apply the cleavage force in order to control the crack speed. In particular, it is shown that it is likely that this technique caused the fracture to propagate at a lower speed. The sacrifice of a large diamond with the intention of creating thin plates, rather than a faceted gemstone, demonstrates how symbolism and beliefs associated with gemstones have changed over the centuries (Harlow GE. 1998 The nature

ROLE OF DIAMOND SECONDARY EMITTERS IN HIGH BRIGHTNESS ELECTRON SOURCES

International Nuclear Information System (INIS)

2005-01-01

In this paper we explore the possibility of using diamond secondary emitter in a high average current electron injector to amplify the current from the photocathode and to isolate the cathode and the injector from each other to increase the life time of the cathode and preserve the performance of the injector. Secondary electron yield of 225 and current density of 0.8 a/cm 2 have been measured in the transmission mode from type 2 a natural diamond. Although the diamond will be heated during normal operation in the injector, calculations indicate that by cryogenically cooling the diamond, the temperature gradient along the diamond can be maintained within the acceptable range. The electron energy and temporal distributions are expected to be narrow from this device resulting in high brightness beams. Plans are underway to measure the SEY in emission mode, fabricate photocathode-diamond capsule and test diamond and capsule in superconducting RF injector

System Design of a Cheetah Robot Toward Ultra-high Speed

Directory of Open Access Journals (Sweden)

Mantian Li

2014-05-01

Full Text Available High-speed legged locomotion pushes the limits of the most challenging problems of design and development of the mechanism, also the control and the perception method. The cheetah is an existence proof of concept of what we imitate for high-speed running, and provides us lots of inspiration on design. In this paper, a new model of a cheetah-like robot is developed using anatomical analysis and design. Inspired by a biological neural mechanism, we propose a novel control method for controlling the muscles' flexion and extension, and simulations demonstrate good biological properties and leg's trajectory. Next, a cheetah robot prototype is designed and assembled with pneumatic muscles, a musculoskeletal structure, an antagonistic muscle arrangement and a J-type cushioning foot. Finally, experiments of the robot legs swing and kick ground tests demonstrate its natural manner and validate the design of the robot. In the future, we will test the bounding behaviour of a real legged system.

The solutions of the n-dimensional Bessel diamond operator and the ...

Indian Academy of Sciences (India)

R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

Introduction. Gelfand and Shilov [2] have first introduced the elementary solution of the n-dimensional classical diamond operator. Later, Kananthai [3–5] has proved the distribution related to the n-dimensional ultra-hyperbolic equation, the solutions of n-dimensional classical diamond operator and Fourier transformation of ...

Diamond anvil cells using boron-doped diamond electrodes covered with undoped diamond insulating layer

Science.gov (United States)

Matsumoto, Ryo; Yamashita, Aichi; Hara, Hiroshi; Irifune, Tetsuo; Adachi, Shintaro; Takeya, Hiroyuki; Takano, Yoshihiko

2018-05-01

Diamond anvil cells using boron-doped metallic diamond electrodes covered with undoped diamond insulating layers have been developed for electrical transport measurements under high pressure. These designed diamonds were grown on a bottom diamond anvil via a nanofabrication process combining microwave plasma-assisted chemical vapor deposition and electron beam lithography. The resistance measurements of a high-quality FeSe superconducting single crystal under high pressure were successfully demonstrated by just putting the sample and gasket on the bottom diamond anvil directly. The superconducting transition temperature of the FeSe single crystal was increased to up to 43 K by applying uniaxial-like pressure.

Diamond Windows for High Powered Microwave Transmission. Final Report

International Nuclear Information System (INIS)

Gat, R.

2011-01-01

This phase II SBIR developed technology for manufacturing diamond windows for use in high energy density photon transmission e.g. microwave or laser light photons. Microwave sources used in fusion research require microwave extraction windows with high thermal conductivity, low microwave absorption, and low resistance to thermal cracking. Newly developed, man made diamond windows have all three of these properties, but these windows are prohibitively expensive. This limits the natural progress of these important technologies to higher powers and slows the development of additional applications. This project developed a lower cost process for manufacturing diamond windows using microwave plasma. Diamond windows were deposited. A grinding process was used to provide optical smoothness for 2 cm diameter diamond windows that met the parallelism specifications for fusion beam windows. The microwave transmission performance (loss tangent) of one of the windows was measured at 95GHz to be less than 10-4, meeting specifications for utilization in the ITER tokamak.

Dynamical fragmentation and very high speed projection of micro-particulates with a pulsed electrons generator

International Nuclear Information System (INIS)

Cassany, B.; Courchinoux, R.; Bertron, I.; Malaise, F.; Hebert, D.

2003-01-01

This paper shows how to use a pulsed electrons beam to simulate the dynamical fragmentation of copper sheets and to eject diamond, tantalum and tungsten micro-particulates at very high speed (∼1000 m/s). These experiments were performed with the electrons generator CESAR of CEA/CESTA (France). (J.S.)

Ultra-high temperature direct propulsion

International Nuclear Information System (INIS)

Araj, K.J.; Slovik, G.; Powell, J.R.; Ludewig, H.

1987-01-01

Potential advantages of ultra-high exhaust temperature (3000 K - 4000 K) direct propulsion nuclear rockets are explored. Modifications to the Particle Bed Reactor (PBR) to achieve these temperatures are described. Benefits of ultra-high temperature propulsion are discussed for two missions - orbit transfer (ΔV = 5546 m/s) and interplanetary exploration (ΔV = 20000 m/s). For such missions ultra-high temperatures appear to be worth the additional complexity. Thrust levels are reduced substantially for a given power level, due to the higher enthalpy caused by partial disassociation of the hydrogen propellant. Though technically challenging, it appears potentially feasible to achieve such ultra high temperatures using the PBR

Ultra-High-Speed Travelling Wave Protection of Transmission Line Using Polarity Comparison Principle Based on Empirical Mode Decomposition

Directory of Open Access Journals (Sweden)

Dong Wang

2015-01-01

Full Text Available The traditional polarity comparison based travelling wave protection, using the initial wave information, is affected by initial fault angle, bus structure, and external fault. And the relationship between the magnitude and polarity of travelling wave is ignored. Because of the protection tripping and malfunction, the further application of this protection principle is affected. Therefore, this paper presents an ultra-high-speed travelling wave protection using integral based polarity comparison principle. After empirical mode decomposition of the original travelling wave, the first-order intrinsic mode function is used as protection object. Based on the relationship between the magnitude and polarity of travelling wave, this paper demonstrates the feasibility of using travelling wave magnitude which contains polar information as direction criterion. And the paper integrates the direction criterion in a period after fault to avoid wave head detection failure. Through PSCAD simulation with the typical 500 kV transmission system, the reliability and sensitivity of travelling wave protection were verified under different factors’ affection.

An Ultra-High Speed Whole Slide Image Viewing System

Directory of Open Access Journals (Sweden)

Yukako Yagi

2012-01-01

Full Text Available Background: One of the goals for a Whole Slide Imaging (WSI system is implementation in the clinical practice of pathology. One of the unresolved problems in accomplishing this goal is the speed of the entire process, i.e., from viewing the slides through making the final diagnosis. Most users are not satisfied with the correct viewing speeds of available systems. We have evaluated a new WSI viewing station and tool that focuses on speed.

Determination of high-strength materials diamond grinding rational modes

Science.gov (United States)

Arkhipov, P. V.; Lobanov, D. V.; Rychkov, D. A.; Yanyushkin, A. S.

2018-03-01

The analysis of methods of high-strength materials abrasive processing is carried out. This method made it possible to determine the necessary directions and prospects for the development of shaping combined methods. The need to use metal bonded diamond abrasive tools in combination with a different kind of energy is noted to improve the processing efficiency and reduce the complexity of operations. The complex of experimental research on revealing the importance of mechanical and electrical components of cutting regimes, on the cutting ability of diamond tools, as well as the need to reduce the specific consumption of an abrasive wheel as one of the important economic indicators of the processing process is performed. It is established that combined diamond grinding with simultaneous continuous correction of the abrasive wheel contributes to an increase in the cutting ability of metal bonded diamond abrasive tools when processing high-strength materials by an average of 30% compared to diamond grinding. Particular recommendations on the designation of technological factors are developed depending on specific production problems.

CVD Diamond Sensors In Detectors For High Energy Physics

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00334150; Trischuk, William

At the end of the next decade an upgrade of the Large Hadron Collider (LHC) to High Luminosity LHC (HL-LHC) is planned which requires the development of new radiation tolerant sensor technology. Diamond is an interesting material for use as a particle detector in high radiation environments. The large band gap ($5.47\\,\\text{eV}$) and the large displacement energy suggest that diamond is a radiation tolerant detector material. In this Thesis the capability of Chemical Vapor Deposition (CVD) diamond as such a sensor technology is investigated. The radiation damage constant for $800\\,\\text{MeV}$ protons is measured using single crystalline CVD (scCVD) and polycrystalline CVD (pCVD) diamonds irradiated to particle fluences up to $12 \\times 10^{15}\\,\\text{p/cm}^2$. In addition the signal response of a pCVD diamond detector after an irradiation to $12 \\times 10^{15}\\,\\text{p/cm}^2$ is investigated to determine if such a detector can be operated efficiently in the expected HL-LHC environment. By using electrodes em...

Arc Shape Characteristics with Ultra-High-Frequency Pulsed Arc Welding

Directory of Open Access Journals (Sweden)

Mingxuan Yang

2017-01-01

Full Text Available Arc plasma possesses a constriction phenomenon with a pulsed current. The constriction is created by the Lorentz force, the radial electromagnetic force during arc welding, which determines the energy distribution of the arc plasma. Welding experiments were carried out with ultra-high-frequency pulsed arc welding (UHFP-AW. Ultra-high-speed camera observations were produced for arc surveillance. Hue-saturation-intensity (HSI image analysis was used to distinguish the regions of the arc plasma that represented the heat energy distribution. The measurement of arc regions indicated that, with an ultra-high-frequency pulsed arc, the constriction was not only within the decreased arc geometry, but also within the constricted arc core region. This can be checked by the ratio of the core region to the total area. The arc core region expanded significantly at 40 kHz at 60 A. A current level of 80 A caused a decrease in the total region of the arc. Meanwhile, the ratio of the core region to the total increased. It can be concluded that arc constriction depends on the increased area of the core region with the pulsed current (>20 kHz.

High speed all optical shear wave imaging optical coherence elastography (Conference Presentation)

Science.gov (United States)

Song, Shaozhen; Hsieh, Bao-Yu; Wei, Wei; Shen, Tueng; O'Donnell, Matthew; Wang, Ruikang K.

2016-03-01

Optical Coherence Elastography (OCE) is a non-invasive testing modality that maps the mechanical property of soft tissues with high sensitivity and spatial resolution using phase-sensitive optical coherence tomography (PhS-OCT). Shear wave OCE (SW-OCE) is a leading technique that relies on the speed of propagating shear waves to provide a quantitative elastography. Previous shear wave imaging OCT techniques are based on repeated M-B scans, which have several drawbacks such as long acquisition time and repeated wave stimulations. Recent developments of Fourier domain mode-locked high-speed swept-source OCT system has enabled enough speed to perform KHz B-scan rate OCT imaging. Here we propose ultra-high speed, single shot shear wave imaging to capture single-shot transient shear wave propagation to perform SW-OCE. The frame rate of shear wave imaging is 16 kHz, at A-line rate of ~1.62 MHz, which allows the detection of high-frequency shear wave of up to 8 kHz. The shear wave is generated photothermal-acoustically, by ultra-violet pulsed laser, which requires no contact to OCE subjects, while launching high frequency shear waves that carries rich localized elasticity information. The image acquisition and processing can be performed at video-rate, which enables real-time 3D elastography. SW-OCE measurements are demonstrated on tissue-mimicking phantoms and porcine ocular tissue. This approach opens up the feasibility to perform real-time 3D SW-OCE in clinical applications, to obtain high-resolution localized quantitative measurement of tissue biomechanical property.

Diamond x-ray optics: Transparent, resilient, high-resolution, and wavefront preserving

International Nuclear Information System (INIS)

Shvyd’ko, Yuri; Blank, Vladimir; Terentyev, Sergey

2017-01-01

Diamond features a unique combination of outstanding physical properties perfect for numerous x-ray optics applications, where traditional materials such as silicon fail to perform. In the last two decades, impressive progress has been achieved in synthesizing diamond with high crystalline perfection, in manufacturing efficient, resilient, high-resolution, wavefront-preserving diamond optical components, and in implementing them in cutting-edge x-ray instruments. Diamond optics are essential for tailoring x-rays to the most challenging needs of x-ray research. Furthermore, they are becoming vital for the generation of fully coherent hard x-rays by seeded x-ray free-electron lasers. In this article, we review progress in manufacturing flawless diamond crystal components and their applications in diverse x-ray optical devices, such as x-ray monochromators, beam splitters, high-reflectance backscattering mirrors, lenses, phase plates, diffraction gratings, bent-crystal spectrographs, and windows.

Studies on synthesis of diamond at high pressure and temperature

Science.gov (United States)

Kailath, Ansu J.

Diamond is an essential material of modern industry and probably the most versatile abrasive available today. It also has many other industrial applications attributable to its unique mechanical, optical, thermal and electrical properties. Its usage has grown to the extent that there is hardly a production process in modern industry in which industrial diamond does not play a part. Bulk diamond production today is a major industry. Diamonds can be produced in its thermodynamically stable regions either by direct static conversion, or shock-wave conversion. The pressures and temperatures required for direct static conversion are very high. In the catalyst-solvent method, the material used establishes a reaction path with lower activation energy than for direct transformation. This helps in a quicker transformation under more benign conditions. Hence, catalyst-solvent synthesis is readily accomplished and is now a viable and successful industrial process. Diamonds produced by shock wave are very small (approximately 60mu). Therefore this diamond is limited to applications such as polishing compounds only. The quality, quantity, size and morphology of the crystals synthesized by catalyst-solvent process depend on different conditions employed for synthesis. These details, because of commercial reasons are not disclosed in published literature. Hence, systematic studies have been planned to investigate the effect of various growth parameters on the synthesized crystals. During the growth of synthetic diamond crystals, some catalyst-solvent is retained into the crystals in some form and behaves like an impurity. Several physico-mechanical properties of the crystals are found to depend on the total quantity and distribution of these inclusions. Thus, detailed investigation of the crystallization medium and inclusions in synthesized diamonds was also undertaken in the present work. The work incorporated in this thesis has been divided into seven chapters. The first

Ultra high-speed (508 MHz) beam position digital feedback system

International Nuclear Information System (INIS)

Kurokawa, Shin-ichi; Kametani, Masatsugu; Nakayama, Takahide; Moriyama, Kunio.

1997-01-01

The B-Factory which is constructed by National Laboratory for High Energy Physics is the device for elucidating the breakdown of symmetry of matter and antimatter by studying the behavior of B mesons which are generated in large quantity when the electrons and the positrons which are accelerated to light velocity level are collided. In order to maintain electron beam-positron beam bunch circling the ring at light velocity stably, the instability of the coupled bunch must be overcome. For this purpose, the ultrahigh speed beam position digital feedback control system was developed. This system is composed of the high speed input-output substrate using GaAs LSI, the feedback computation substrate using complementary metal oxide semiconductor and the memory mounted on it, and the real time operation device. The development of both substrates and their functions are explained. The real time data collection and the change of computation parameters for specific bunch in the real time operation device have become feasible. The signal transmission characteristics of this system are shown. As the result of the action test of this system, it was confirmed to work normally. (K.I.)

Tracing the depositional history of Kalimantan diamonds by zircon provenance and diamond morphology studies

Science.gov (United States)

Kueter, Nico; Soesilo, Joko; Fedortchouk, Yana; Nestola, Fabrizio; Belluco, Lorenzo; Troch, Juliana; Wälle, Markus; Guillong, Marcel; Von Quadt, Albrecht; Driesner, Thomas

2016-11-01

Diamonds in alluvial deposits in Southeast Asia are not accompanied by indicator minerals suggesting primary kimberlite or lamproite sources. The Meratus Mountains in Southeast Borneo (Province Kalimantan Selatan, Indonesia) provide the largest known deposit of these so-called "headless" diamond deposits. Proposals for the origin of Kalimantan diamonds include the adjacent Meratus ophiolite complex, ultra-high pressure (UHP) metamorphic terranes, obducted subcontinental lithospheric mantle and undiscovered kimberlite-type sources. Here we report results from detailed sediment provenance analysis of diamond-bearing Quaternary river channel material and from representative outcrops of the oldest known formations within the Alino Group, including the diamond-bearing Campanian-Maastrichtian Manunggul Formation. Optical examination of surfaces of diamonds collected from artisanal miners in the Meratus area (247 stones) and in West Borneo (Sanggau Area, Province Kalimantan Barat; 85 stones) points toward a classical kimberlite-type source for the majority of these diamonds. Some of the diamonds host mineral inclusions suitable for deep single-crystal X-ray diffraction investigation. We determined the depth of formation of two olivines, one coesite and one peridotitic garnet inclusion. Pressure of formation estimates for the peridotitic garnet at independently derived temperatures of 930-1250 °C are between 4.8 and 6.0 GPa. Sediment provenance analysis includes petrography coupled to analyses of detrital garnet and glaucophane. The compositions of these key minerals do not indicate kimberlite-derived material. By analyzing almost 1400 zircons for trace element concentrations with laser ablation ICP-MS (LA-ICP-MS) we tested the mineral's potential as an alternative kimberlite indicator. The screening ultimately resulted in a small subset of ten zircons with a kimberlitic affinity. Subsequent U-Pb dating resulting in Cretaceous ages plus a detailed chemical reflection make

High-Density Near-Field Readout Using Diamond Solid Immersion Lens

Science.gov (United States)

Shinoda, Masataka; Saito, Kimihiro; Kondo, Takao; Nakaoki, Ariyoshi; Furuki, Motohiro; Takeda, Minoru; Yamamoto, Masanobu; Schaich, Thomas J.; van Oerle, Bart M.; Godfried, Herman P.; Kriele, Paul A. C.; Houwman, Evert P.; Nelissen, Wim H. M.; Pels, Gert J.; Spaaij, Paul G. M.

2006-02-01

We investigated high-density near-field readout using a diamond solid immersion lens (SIL). A synthetic single-crystal chemical vapor deposition diamond provides a high refractive index and a high transmission for a wide wavelength range. Since the refractive index at a wavelength of 405 nm is 2.458, we could design a solid immersion lens with an effective numerical aperture of 2.34. Using the diamond SIL, we observed the eye pattern of a 150-GB-capacity (104.3 Gbit/in.2) disk with a track pitch of 130 nm and a bit length of 47.6 nm.

High pressure sintering (HP-HT) of diamond powders with titanium and titanium carbide

International Nuclear Information System (INIS)

Jaworska, L.

1999-01-01

Polycrystalline diamond compacts for cutting tools are mostly manufactured using high pressure sintering (HP-HT). The standard diamond compacts are prepared by diamond powders sintering with metallic binding phase. The first group of metallic binder are metals able to solve carbon - Co, Ni. The second group of metal binders are carbide forming elements - Ti, Cr, W and others. The paper describes high pressure sintering of diamond powder with titanium and nonstoichiometry titanium carbide for cutting tool application. A type of binding phase has the significant influence on microstructure and mechanical properties of diamond compacts. Very homogeneous structure was achieved in case of compacts obtained from metalized diamond where diamond-TiC-diamond connection were predominant. In the case of compacts prepared by mechanical mixing of diamond with titanium powders the obtained structure was nonhomogeneous with titanium carbide clusters. They had more diamond to diamond connections. These compacts compared to the compact made of metallized diamond have greater wear resistance. In the case of the diamond and TiC 0.92 sintering the strong bonding of TiC diamond grains was obtained. The microstructure observations for diamond with 5% wt. Ti and diamond with 5% wt. TiC 0.92 (the initial composition) compacts were performed in transmission microscope. For two type of compacts the strong bonding phase TiC without defects is creating. (author)

TECHNICAL NOTE: High-speed grinding using thin abrasive disks for microcomponents

Science.gov (United States)

Yeo, S. H.; Balon, S. A. P.

2002-01-01

This paper introduces the development of a high-speed grinding device for cylindrical grinding of microcomponents made of hard and brittle materials. The study made use of an ultraprecision diamond turning machine tool as a basic platform. The novelty of the device is based on the high-speed air bearing spindle with a thin grinding wheel, similar to the dicing technology for silicon wafer fabrication. The spindle attachment is inclined at an angle to the main spindle which holds the precision fixture mechanism via the vacuum chuck. Experiments have been conducted to verify the design and implementation of the grinding methodology. A feature size as small as 31 μm in diameter and average surface roughness of 98 nm were obtained in the experimental work. It is found that the work done is capable of manufacturing miniature components, such as microcylindrical stepped shafts.

Highly charged ion impact induced nanodefects in diamond

Energy Technology Data Exchange (ETDEWEB)

Makgato, T.N., E-mail: thuto.makgato@wits.ac.za [School of Physics, University of the Witwatersrand, Johannesburg 2050 (South Africa); Microscopy and Microanalysis Unit, University of the Witwatersrand, Johannesburg 2050 (South Africa); Sideras-Haddad, E. [School of Physics, University of the Witwatersrand, Johannesburg 2050 (South Africa); Centre of Excellence in Strong Materials, Physics Building, University of the Witwatersrand, Johannesburg 2050 (South Africa); Shrivastava, S. [School of Physics, University of the Witwatersrand, Johannesburg 2050 (South Africa); Schenkel, T. [E.O. Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Ritter, R.; Kowarik, G.; Aumayr, F. [Institute of Applied Physics, TU Wien-Vienna University of Technology, 1040 Vienna (Austria); Crespo Lopez-Urrutia, J.; Bernitt, S.; Beilmann, C.; Ginzel, R. [Max-Planck Institute for Nuclear Physics, Saupfercheckweg 1, 69117 Heidelberg (Germany)

2013-11-01

We investigate the interaction of slow highly charged ion (SHCI) beams with insulating type Ib diamond (1 1 1) surfaces. Bismuth and Xenon SHCI beams produced using an Electron Beam Ion Trap (EBIT) and an Electron Cyclotron Resonance source (ECR) respectively, are accelerated onto type Ib diamond (1 1 1) surfaces with impact velocities up to ≈0.4 υ{sub Bohr}. SHCIs with charge states corresponding to potential energies between 4.5 keV and 110 keV are produced for this purpose. Atomic Force Microscopy analysis (AFM) of the diamond surfaces following SHCI impact reveals surface morphological modifications characterized as nanoscale craters (nano-craters). To interpret the results from Tapping Mode AFM analysis of the irradiated diamond surfaces we discuss the interplay between kinetic and potential energy in nano-crater formation using empirical data together with Stopping and Range of Ions in Matter (SRIM) Monte Carlo Simulations.

Ultra-high density aligned Carbon-nanotube with controled nano-morphology for supercapacitors

Science.gov (United States)

Ghaffari, Mehdi; Zhao, Ran; Liu, Yang; Zhou, Yue; Cheng, Jiping; Guzman de Villoria, Roberto; Wardle, B. L.; Zhang, Q. M.

2012-02-01

Recent advances in fabricating controlled-morphology vertically aligned carbon nanotubes (VA-CNTs) with ultrahigh volume fractioncreate unique opportunities for developing unconventional supercapacitors with ultra-high energy density, power density, and long charge/discharge cycle life.Continuous paths through inter-VA-CNT channels allow fast ion transport, and high electrical conduction of the aligned CNTs in the composite electrodes lead to fast discharge speed. We investigate the charge-discharge characteristics of VA-CNTs with >20 vol% of CNT and ionic liquids as electrolytes. By employing both the electric and electromechanical spectroscopes, as well as nanostructured materials characterization, the ion transport and storage behaviors in porous electrodes are studied. The results suggest pathways for optimizing the electrode morphology in supercapacitorsusing ultra-high volume fraction VA-CNTs to further enhance performance.

Diamond and silicon pixel detectors in high radiation environments

Energy Technology Data Exchange (ETDEWEB)

Tsung, Jieh-Wen

2012-10-15

Diamond pixel detector is a promising candidate for tracking of collider experiments because of the good radiation tolerance of diamond. The diamond pixel detector must withstand the radiation damage from 10{sup 16} particles per cm{sup 2}, which is the expected total fluence in High Luminosity Large Hadron Collider. The performance of diamond and silicon pixel detectors are evaluated in this research in terms of the signal-to-noise ratio (SNR). Single-crystal diamond pixel detectors with the most recent readout chip ATLAS FE-I4 are produced and characterized. Based on the results of the measurement, the SNR of diamond pixel detector is evaluated as a function of radiation fluence, and compared to that of planar-silicon ones. The deterioration of signal due to radiation damage is formulated using the mean free path of charge carriers in the sensor. The noise from the pixel readout circuit is simulated and calculated with leakage current and input capacitance to the amplifier as important parameters. The measured SNR shows good agreement with the calculated and simulated results, proving that the performance of diamond pixel detectors can exceed the silicon ones if the particle fluence is more than 10{sup 15} particles per cm{sup 2}.

Diamond and silicon pixel detectors in high radiation environments

International Nuclear Information System (INIS)

Tsung, Jieh-Wen

2012-10-01

Diamond pixel detector is a promising candidate for tracking of collider experiments because of the good radiation tolerance of diamond. The diamond pixel detector must withstand the radiation damage from 10 16 particles per cm 2 , which is the expected total fluence in High Luminosity Large Hadron Collider. The performance of diamond and silicon pixel detectors are evaluated in this research in terms of the signal-to-noise ratio (SNR). Single-crystal diamond pixel detectors with the most recent readout chip ATLAS FE-I4 are produced and characterized. Based on the results of the measurement, the SNR of diamond pixel detector is evaluated as a function of radiation fluence, and compared to that of planar-silicon ones. The deterioration of signal due to radiation damage is formulated using the mean free path of charge carriers in the sensor. The noise from the pixel readout circuit is simulated and calculated with leakage current and input capacitance to the amplifier as important parameters. The measured SNR shows good agreement with the calculated and simulated results, proving that the performance of diamond pixel detectors can exceed the silicon ones if the particle fluence is more than 10 15 particles per cm 2 .

Laser plasma generation of hydrogen-free diamond-like carbon thin films on Zr-2.5Nb CANDU pressure tube materials and silicon wafers with a pulsed high-power CO2 laser

International Nuclear Information System (INIS)

Ebrahim, N.A.; Mouris, J.F.; Hoffmann, C.R.J.; Davis, R.W.

1995-06-01

We report the first experiments on the laser plasma deposition of hydrogen-free, diamond-like carbon (DLC) films on Zr-2.5Nb CANDU pressure-tube materials and silicon substrates, using the short-pulse, high-power, CO 2 laser in the High-Power Laser Laboratory at Chalk River Laboratories. The films were (AFM). The thin films show the characteristic signature of DLC films in the Raman spectra obtained using a krypton-ion (Kr + ) laser. The Vickers ultra-low-load microhardness tests show hardness of the coated surface of approximately 7000 Kg force mm -2 , which is consistent with the hardness associated with DLC films. AFM examination of the film morphology shows diamond-like crystals distributed throughout the film, with film thicknesses of up to 0.5 μm generated with 50 laser pulses. With significantly more laser pulses, it is expected that very uniform diamond-like films would be produced. These experiments suggest that it should be possible to deposit hydrogen-free, diamond-like films of relevance to nuclear reactor components with a high-power and high-repetition-rate laser facility. (author). 7 refs., 2 tabs., 15 figs

Influences of Cutting Speed and Material Mechanical Properties on Chip Deformation and Fracture during High-Speed Cutting of Inconel 718

Directory of Open Access Journals (Sweden)

Bing Wang

2018-03-01

Full Text Available The paper aims to investigate the influences of material constitutive and fracture parameters in addition to cutting speed on chip formation during high-speed cutting of Inconel 718. Finite element analyses for chip formation are conducted with Johnson–Cook constitutive and fracture models. Meanwhile, experiments of high-speed orthogonal cutting are performed to verify the simulation results with cutting speeds ranging from 50 m/min to 7000 m/min. The research indicates that the chip morphology transforms from serrated to fragmented at the cutting speed of 7000 m/min due to embrittlement of the workpiece material under ultra-high cutting speeds. The parameter of shear localization sensitivity is put forward to describe the influences of material mechanical properties on serrated chip formation. The results demonstrate that the effects of initial yield stress and thermal softening coefficient on chip shear localization are much more remarkable than the other constitutive parameters. For the material fracture parameters, the effects of initial fracture strain and exponential factor of stress state on chip shear localization are more much prominent. This paper provides guidance for controlling chip formation through the adjustment of material mechanical properties and the selection of appropriate cutting parameters.

Influences of Cutting Speed and Material Mechanical Properties on Chip Deformation and Fracture during High-Speed Cutting of Inconel 718.

Science.gov (United States)

Wang, Bing; Liu, Zhanqiang; Hou, Xin; Zhao, Jinfu

2018-03-21

The paper aims to investigate the influences of material constitutive and fracture parameters in addition to cutting speed on chip formation during high-speed cutting of Inconel 718. Finite element analyses for chip formation are conducted with Johnson-Cook constitutive and fracture models. Meanwhile, experiments of high-speed orthogonal cutting are performed to verify the simulation results with cutting speeds ranging from 50 m/min to 7000 m/min. The research indicates that the chip morphology transforms from serrated to fragmented at the cutting speed of 7000 m/min due to embrittlement of the workpiece material under ultra-high cutting speeds. The parameter of shear localization sensitivity is put forward to describe the influences of material mechanical properties on serrated chip formation. The results demonstrate that the effects of initial yield stress and thermal softening coefficient on chip shear localization are much more remarkable than the other constitutive parameters. For the material fracture parameters, the effects of initial fracture strain and exponential factor of stress state on chip shear localization are more much prominent. This paper provides guidance for controlling chip formation through the adjustment of material mechanical properties and the selection of appropriate cutting parameters.

High power CO2 laser development with AOM integration for ultra high-speed pulses

Science.gov (United States)

Bohrer, Markus; Vaupel, Matthias; Nirnberger, Robert; Weinberger, Bernhard; Jamalieh, Murad

2017-01-01

There is a 500 billion USD world market for packaging expected to grow to a trillion in 2030. Austria plays an important role world wide for high speed laser engraving applications — especially when it comes to high end solutions. Such high end solutions are fundamental for the production of print forms for the packaging and decorating industry (e. g. cans). They are additionally used for security applications (e. g. for printing banknotes), for the textile printing industry and for creating embossing forms (e. g. for the production of dashboards in the automotive industry). High speed, high precision laser engraving needs laser resonators with very stable laser beams (400 - 800W) especially in combination with AOMs. Based upon a unique carbon fiber structure - stable within the sub-micrometer range - a new resonator has been developed, accompanied by most recent thermo-mechanical FEM calculations. The resulting beam is evaluated on an automated optical bench using hexapods, allowing to optimize the complete beam path with collimators and AOM. The major steps related to laser engraving of dry offset printing plates during the full workflow from the artists design to the printed result on an aluminum can is presented in this paper as well as laser characteristics, AOM integration and correlative CLSM and SEM investigation of the results.

An Analysis of an Ultra-High Speed Content-Addressable Database Retrieval System

National Research Council Canada - National Science Library

Costianes, Peter

2001-01-01

...) and its implementation as a high speed optical chip. The paradigm uses polarization states to represent binary very words and EO modulators to represent database words to perform what is essentially XOR operations...

Possibilities of rotating drums in ultra-high-speed cinematography

International Nuclear Information System (INIS)

Andre, Michel

A theoretical study shows that it is possible to produce a drum rotating at a peripheral speed of 500m/s. A prototype has actually reached this speed and confirmed the feasibility of the system. It is driven by an electric motor and is made of titanium covered with boron fibres. The main performances to be expected of cameras (whole-image, slit or spectrographic) using such a drum is described [fr

Diamond-turning HP-21 beryllium to achieve an optical surface

International Nuclear Information System (INIS)

Allen, D.K.; Hauschildt, H.W.; Bryan, J.B.

1975-01-01

Investigation of diamond turning on beryllium was made in anticipation of obtaining an optical finish. Although results of past experiences were poor, it was decided to continue diamond turning on beryllium beyond initial failures. By changing speed and using coolant, partial success was achieved. Tool wear was the major problem. Tests were made to establish and plot wear as a function of cutting speed and time. Slower speeds did cause lower wear rates, but at no time did wear reach an acceptable level. The machine, tools, and procedure used were chosen based on the results of preliminary attempts and on previous experience. It was unnecessary to use an air-bearing spindle because tool failure governed the best finish that could be expected. All tools of diamond composition, whether single crystal or polycrystalline, wore at unacceptable rates. Based on present technology, it must be concluded that beryllium cannot be feasibly diamond turned to achieve an optical finish. (22 fig.)

No speed limits in medical imaging and high-energy physics

CERN Multimedia

Rita Giuffredi & Tom Meyer

2015-01-01

Speed, or high time resolution, is becoming increasingly important, if not crucial, in the high-energy physics domain, both for particle acceleration and detection systems. Medical-imaging technology also vitally depends on high time resolution detection techniques, often the offspring of today’s large particle physics experiments. The four-year FP7 Marie Curie Training Project “PicoSEC-MCNet”, which draws to a close at the end of November, was designed to develop ultra-fast photon detectors for applications in both domains. The project has achieved important results that promise to trigger further developments in the years to come.   The PicoSEC-MCNet project participants. “New requirements in high-energy physics force us to push the limits of photon detection speed, as future high-luminosity accelerators will force us to cope with the unprecedentedly short bunch crossing intervals needed to produce sufficient luminosity,” explains Tom M...

Diamond monochromator for high heat flux synchrotron x-ray beams

International Nuclear Information System (INIS)

Khounsary, A.M.; Smither, R.K.; Davey, S.; Purohit, A.

1992-12-01

Single crystal silicon has been the material of choice for x-ray monochromators for the past several decades. However, the need for suitable monochromators to handle the high heat load of the next generation synchrotron x-ray beams on the one hand and the rapid and on-going advances in synthetic diamond technology on the other make a compelling case for the consideration of a diamond mollochromator system. In this Paper, we consider various aspects, advantage and disadvantages, and promises and pitfalls of such a system and evaluate the comparative an monochromator subjected to the high heat load of the most powerful x-ray beam that will become available in the next few years. The results of experiments performed to evaluate the diffraction properties of a currently available synthetic single crystal diamond are also presented. Fabrication of diamond-based monochromator is within present technical means

High collection efficiency CVD diamond alpha detectors

International Nuclear Information System (INIS)

Bergonzo, P.; Foulon, F.; Marshall, R.D.; Jany, C.; Brambilla, A.; McKeag, R.D.; Jackman, R.B.

1998-01-01

Advances in Chemical Vapor Deposited (CVD) diamond have enabled the routine use of this material for sensor device fabrication, allowing exploitation of its unique combination of physical properties (low temperature susceptibility (> 500 C), high resistance to radiation damage (> 100 Mrad) and to corrosive media). A consequence of CVD diamond growth on silicon is the formation of polycrystalline films which has a profound influence on the physical and electronic properties with respect to those measured on monocrystalline diamond. The authors report the optimization of physical and geometrical device parameters for radiation detection in the counting mode. Sandwich and co-planar electrode geometries are tested and their performances evaluated with regard to the nature of the field profile and drift distances inherent in such devices. The carrier drift length before trapping was measured under alpha particles and values as high as 40% of the overall film thickness are reported. Further, by optimizing the device geometry, they show that a gain in collection efficiency, defined as the induced charge divided by the deposited charge within the material, can be achieved even though lower bias values are used

High-Q/V Monolithic Diamond Microdisks Fabricated with Quasi-isotropic Etching.

Science.gov (United States)

Khanaliloo, Behzad; Mitchell, Matthew; Hryciw, Aaron C; Barclay, Paul E

2015-08-12

Optical microcavities enhance light-matter interactions and are essential for many experiments in solid state quantum optics, optomechanics, and nonlinear optics. Single crystal diamond microcavities are particularly sought after for applications involving diamond quantum emitters, such as nitrogen vacancy centers, and for experiments that benefit from diamond's excellent optical and mechanical properties. Light-matter coupling rates in experiments involving microcavities typically scale with Q/V, where Q and V are the microcavity quality-factor and mode-volume, respectively. Here we demonstrate that microdisk whispering gallery mode cavities with high Q/V can be fabricated directly from bulk single crystal diamond. By using a quasi-isotropic oxygen plasma to etch along diamond crystal planes and undercut passivated diamond structures, we create monolithic diamond microdisks. Fiber taper based measurements show that these devices support TE- and TM-like optical modes with Q > 1.1 × 10(5) and V < 11(λ/n) (3) at a wavelength of 1.5 μm.

The potential application of ultra-nanocrystalline diamond films for heavy ion irradiation detection

Energy Technology Data Exchange (ETDEWEB)

Chen, Huang-Chin [Department of Physics, Tamkang University, Tamsui, New-Taipei, Taiwan 251 (China); Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, Taiwan, 300 (China); Chen, Shih-Show [Department of Physics, Tamkang University, Tamsui, New-Taipei, Taiwan 251 (China); Department of Information Technology and Mobile Communication, Taipei College of Maritime Technology, Tamsui, New-Taipei, Taiwan 251 (China); Wang, Wei-Cheng; Lin, I-Nan; Chang, Ching-Lin [Department of Physics, Tamkang University, Tamsui, New-Taipei, Taiwan 251 (China); Lee, Chi-Young [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, Taiwan, 300 (China); Guo, Jinghua [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

2013-06-15

The potential of utilizing the ultra-nanocrystalline (UNCD) films for detecting the Au-ion irradiation was investigated. When the fluence for Au-ion irradiation is lower than the critical value (f{sub c}= 5.0 Multiplication-Sign 10{sup 12} ions/cm{sup 2}) the turn-on field for electron field emission (EFE) process of the UNCD films decreased systematically with the increase in fluence that is correlated with the increase in sp{sup 2}-bonded phase ({pi}{sup *}-band in EELS) due to the Au-ion irradiation. The EFE properties changed irregularly, when the fluence for Au-ion irradiation exceeds this critical value. The transmission electron microscopic microstructural examinations, in conjunction with EELS spectroscopic studies, reveal that the structural change preferentially occurred in the diamond-to-Si interface for the samples experienced over critical fluence of Au-ion irradiation, viz. the crystalline SiC phase was induced in the interfacial region and the thickness of the interface decreased. These observations implied that the UNCD films could be used as irradiation detectors when the fluence for Au-ion irradiation does not exceed such a critical value.

High sensitivity thermal sensors on insulating diamond

Energy Technology Data Exchange (ETDEWEB)

Job, R. [Fernuniversitaet Hagen (Gesamthochschule) (Germany). Electron. Devices; Denisenko, A.V. [Fernuniversitaet Hagen (Gesamthochschule) (Germany). Electron. Devices; Zaitsev, A.M. [Fernuniversitaet Hagen (Gesamthochschule) (Germany). Electron. Devices; Melnikov, A.A. [Belarussian State Univ., Minsk (Belarus). HEII and FD; Werner, M. [VDI/VDE-IT, Teltow (Germany); Fahrner, W.R. [Fernuniversitaet Hagen (Gesamthochschule) (Germany). Electron. Devices

1996-12-15

Diamond is a promising material to develop sensors for applications in harsh environments. To increase the sensitivity of diamond temperature sensors the effect of thermionic hole emission (TE) over an energetic barrier formed in the interface between highly boron-doped p-type and intrinsic insulating diamond areas has been suggested. To study the TE of holes a p-i-p diode has been fabricated and analyzed by electrical measurements in the temperature range between 300 K and 700 K. The experimental results have been compared with numerical simulations of its electrical characteristics. Based on a model of the thermionic emission of carriers into an insulator it has been suggested that the temperature sensitivity of the p-i-p diode on diamond is strongly affected by the re-emission of holes from a group of donor-like traps located at a level of 0.7-1.0 eV above the valence band. The mechanism of thermal activation of the current includes a spatial redistribution of the potential, which results in the TE regime from a decrease of the immobilized charge of the ionized traps within the i-zone of the diode and the correspondent lowering of the forward biased barrier. The characteristics of the p-i-p diode were studied with regard to temperature sensor applications. The temperature coefficient of resistance (TCR=-0.05 K{sup -1}) for temperatures above 600 K is about four times larger than the maximal attainable TCR for conventional boron-doped diamond resistors. (orig.)

Intrinsically High Thermoelectric Performance in AgInSe2 n-Type Diamond-Like Compounds.

Science.gov (United States)

Qiu, Pengfei; Qin, Yuting; Zhang, Qihao; Li, Ruoxi; Yang, Jiong; Song, Qingfeng; Tang, Yunshan; Bai, Shengqiang; Shi, Xun; Chen, Lidong

2018-03-01

Diamond-like compounds are a promising class of thermoelectric materials, very suitable for real applications. However, almost all high-performance diamond-like thermoelectric materials are p-type semiconductors. The lack of high-performance n-type diamond-like thermoelectric materials greatly restricts the fabrication of diamond-like material-based modules and their real applications. In this work, it is revealed that n-type AgInSe 2 diamond-like compound has intrinsically high thermoelectric performance with a figure of merit ( zT ) of 1.1 at 900 K, comparable to the best p-type diamond-like thermoelectric materials reported before. Such high zT is mainly due to the ultralow lattice thermal conductivity, which is fundamentally limited by the low-frequency Ag-Se "cluster vibrations," as confirmed by ab initio lattice dynamic calculations. Doping Cd at Ag sites significantly improves the thermoelectric performance in the low and medium temperature ranges. By using such high-performance n-type AgInSe 2 -based compounds, the diamond-like thermoelectric module has been fabricated for the first time. An output power of 0.06 W under a temperature difference of 520 K between the two ends of the module is obtained. This work opens a new window for the applications using the diamond-like thermoelectric materials.

From brittle to ductile: a structure dependent ductility of diamond nanothread.

Science.gov (United States)

Zhan, Haifei; Zhang, Gang; Tan, Vincent B C; Cheng, Yuan; Bell, John M; Zhang, Yong-Wei; Gu, Yuantong

2016-06-07

As a potential building block for the next generation of devices/multifunctional materials that are spreading in almost every technology sector, one-dimensional (1D) carbon nanomaterial has received intensive research interests. Recently, a new ultra-thin diamond nanothread (DNT) has joined this palette, which is a 1D structure with poly-benzene sections connected by Stone-Wales (SW) transformation defects. Using large-scale molecular dynamics simulations, we found that this sp(3) bonded DNT can transition from brittle to ductile behaviour by varying the length of the poly-benzene sections, suggesting that DNT possesses entirely different mechanical responses than other 1D carbon allotropes. Analogously, the SW defects behave like a grain boundary that interrupts the consistency of the poly-benzene sections. For a DNT with a fixed length, the yield strength fluctuates in the vicinity of a certain value and is independent of the "grain size". On the other hand, both yield strength and yield strain show a clear dependence on the total length of DNT, which is due to the fact that the failure of the DNT is dominated by the SW defects. Its highly tunable ductility together with its ultra-light density and high Young's modulus makes diamond nanothread ideal for the creation of extremely strong three-dimensional nano-architectures.

Study of the effects of focused high-energy boron ion implantation in diamond

Science.gov (United States)

Ynsa, M. D.; Agulló-Rueda, F.; Gordillo, N.; Maira, A.; Moreno-Cerrada, D.; Ramos, M. A.

2017-08-01

Boron-doped diamond is a material with a great technological and industrial interest because of its exceptional chemical, physical and structural properties. At modest boron concentrations, insulating diamond becomes a p-type semiconductor and at higher concentrations a superconducting metal at low temperature. The most conventional preparation method used so far, has been the homogeneous incorporation of boron doping during the diamond synthesis carried out either with high-pressure sintering of crystals or by chemical vapour deposition (CVD) of films. With these methods, high boron concentration can be included without distorting significantly the diamond crystalline lattice. However, it is complicated to manufacture boron-doped microstructures. A promising alternative to produce such microstructures could be the implantation of focused high-energy boron ions, although boron fluences are limited by the damage produced in diamond. In this work, the effect of focused high-energy boron ion implantation in single crystals of diamond is studied under different irradiation fluences and conditions. Micro-Raman spectra of the sample were measured before and after annealing at 1000 °C as a function of irradiation fluence, for both superficial and buried boron implantation, to assess the changes in the diamond lattice by the creation of vacancies and defects and their degree of recovery after annealing.

Proceedings of the 17th international congress on high speed photography and photonics. v. 1-2

International Nuclear Information System (INIS)

McDowell, M.W.; Hollingworth, D.

1986-01-01

One of the unique features of this Congress, is that it provides a forum for practitioners from the host country to describe local and unique applications of high speed photography, fifty percent of the papers were presented by local scientists and engineers. The high proportion of contributions relating to the mining industry emphasises South Africa's leading role in this field. One of the objectives of this congress was to introduce the techniques and applications of high speed photography. Topics covered include: mining applications; ballistics, shockwave and detonation studies; laser studies; x-ray applications; image intensifiers; biomechanics; high and ultra high speed applications; holography; schlieren and interferometry; plasma studies; data analysis techniques and diagnostics; and videography

Diamond semiconducting devices

International Nuclear Information System (INIS)

Polowczyk, M.; Klugmann, E.

1999-01-01

Many efforts to apply the semiconducting diamond for construction of electronic elements: resistors, thermistors, photoresistors, piezoresistors, hallotrons, pn diodes, Schottky diodes, IMPATT diodes, npn transistor, MESFETs and MISFETs are reviewed. Considering the possibilities of acceptor and donor doping, electrical resistivity and thermal conductivity of diamond as well as high electric-field breakdown points, that diamond devices could be used at about 30-times higher frequency and more then 8200 times power than silicon devices. Except that, due to high heat resistant of diamond, it is concluded that diamond devices can be used in environment at high temperature, range of 600 o C. (author)

Ultra-high-speed wavelength conversion in a silicon photonic chip

DEFF Research Database (Denmark)

Hu, Hao; Ji, Hua; Galili, Michael

2011-01-01

We have successfully demonstrated all-optical wavelength conversion of a 640-Gbit/s line-rate return-to-zero differential phase-shift keying (RZ-DPSK) signal based on low-power four wave mixing (FWM) in a silicon photonic chip with a switching energy of only ~110 fJ/bit. The waveguide dispersion...... of the silicon nanowire is nano-engineered to optimize phase matching for FWM and the switching power used for the signal processing is low enough to reduce nonlinear absorption from twophoton- absorption (TPA). These results demonstrate that high-speed wavelength conversion is achievable in silicon chips...

Nanostructured diamond coatings for orthopaedic applications

Science.gov (United States)

CATLEDGE, S.A.; THOMAS, V.; VOHRA, Y.K.

2013-01-01

With increasing numbers of orthopaedic devices being implanted, greater emphasis is being placed on ceramic coating technology to reduce friction and wear in mating total joint replacement components, in order to improve implant function and increase device lifespan. In this chapter, we consider ultra-hard carbon coatings, with emphasis on nanostructured diamond, as alternative bearing surfaces for metallic components. Such coatings have great potential for use in biomedical implants as a result of their extreme hardness, wear resistance, low friction and biocompatibility. These ultra-hard carbon coatings can be deposited by several techniques resulting in a wide variety of structures and properties. PMID:25285213

High quality factor gigahertz frequencies in nanomechanical diamond resonators

OpenAIRE

Gaidarzhy, Alexei; Imboden, Matthias; Mohanty, Pritiraj; Rankin, Janet; Sheldon, Brian W.

2007-01-01

We report actuation and detection of gigahertz-range resonance frequencies in nano-crystalline diamond mechanical resonators. High order transverse vibration modes are measured in coupled-beam resonators exhibiting frequencies up to 1.441 GHz. The cantilever-array design of the resonators translates the gigahertz-range resonant motion of micron-long cantilever elements to the displacement of the central supporting structure. Use of nano-crystalline diamond further increases the frequency comp...

Simulation optimization of filament parameters for uniform depositions of diamond films on surfaces of ultra-large circular holes

Energy Technology Data Exchange (ETDEWEB)

Wang, Xinchang, E-mail: wangxinchangz@163.com; Shen, Xiaotian; Sun, Fanghong; Shen, Bin

2016-12-01

Highlights: • A verified simulation model using a novel filament arrangement is constructed. • Influences of filament parameters are clarified. • A coefficient between simulated and experimental results is proposed. • Orthogonal simulations are adopted to optimize filament parameters. • A general filament arrangement suitable for different conditions is determined. - Abstract: Chemical vapor deposition (CVD) diamond films have been widely applied as protective coatings on varieties of anti-frictional and wear-resistant components, owing to their excellent mechanical and tribological properties close to the natural diamond. In applications of some components, the inner hole surface will serve as the working surface that suffers severe frictional or erosive wear. It is difficult to realize uniform depositions of diamond films on surfaces of inner holes, especially ultra-large inner holes. Adopting a SiC compact die with an aperture of 80 mm as an example, a novel filament arrangement with a certain number of filaments evenly distributed on a circle is designed, and specific effects of filament parameters, including the filament number, arrangement direction, filament temperature, filament diameter, circumradius and the downward translation, on the substrate temperature distribution are studied by computational fluid dynamics (CFD) simulations based on the finite volume method (FVM), adopting a modified computational model well consistent with the actual deposition environment. Corresponding temperature measurement experiments are also conducted to verify the rationality of the computational model. From the aspect of depositing uniform boron-doped micro-crystalline, undoped micro-crystalline and undoped fine-grained composite diamond (BDM-UMC-UFGCD) film on such the inner hole surface, filament parameters as mentioned above are accurately optimized and compensated by orthogonal simulations. Moreover, deposition experiments adopting compensated optimized

Friction and wear properties of diamonds and diamond coatings

International Nuclear Information System (INIS)

Hayward, I.P.

1991-01-01

The recent development of chemical vapor deposition techniques for diamond growth enables bearings to be designed which exploit diamond's low friction and extreme resistance to wear. However, currently produced diamond coatings differ from natural diamond surfaces in that they are polycrystalline and faceted, and often contain appreciable amounts of non-diamond material (i.e. graphitic or amorphous carbon). Roughness, in particular, influences the friction and wear properties; rough coatings severely abrade softer materials, and can even wear natural diamond sliders. Nevertheless, the best available coatings exhibit friction coefficients as low as those of natural diamond and are highly resistant to wear. This paper reviews the tribological properties of natural diamond, and compares them with those of chemical vapor deposited diamond coatings. Emphasis is placed on the roles played by roughness and material transfer in controlling frictional behavior. (orig.)

High speed all optical logic gates based on quantum dot semiconductor optical amplifiers.

Science.gov (United States)

Ma, Shaozhen; Chen, Zhe; Sun, Hongzhi; Dutta, Niloy K

2010-03-29

A scheme to realize all-optical Boolean logic functions AND, XOR and NOT using semiconductor optical amplifiers with quantum-dot active layers is studied. nonlinear dynamics including carrier heating and spectral hole-burning are taken into account together with the rate equations scheme. Results show with QD excited state and wetting layer serving as dual-reservoir of carriers, as well as the ultra fast carrier relaxation of the QD device, this scheme is suitable for high speed Boolean logic operations. Logic operation can be carried out up to speed of 250 Gb/s.

Photon-trapping micro/nanostructures for high linearity in ultra-fast photodiodes

Science.gov (United States)

Cansizoglu, Hilal; Gao, Yang; Perez, Cesar Bartolo; Ghandiparsi, Soroush; Ponizovskaya Devine, Ekaterina; Cansizoglu, Mehmet F.; Yamada, Toshishige; Elrefaie, Aly F.; Wang, Shih-Yuan; Islam, M. Saif

2017-08-01

Photodetectors (PDs) in datacom and computer networks where the link length is up to 300 m, need to handle higher than typical input power used in other communication links. Also, to reduce power consumption due to equalization at high speed (>25Gb/s), the datacom links will use PAM-4 signaling instead of NRZ with stringent receiver linearity requirements. Si PDs with photon-trapping micro/nanostructures are shown to have high linearity in output current verses input optical power. Though there is less silicon material due to the holes, the micro-/nanostructured holes collectively reradiate the light to an in-plane direction of the PD surface and can avoid current crowding in the PD. Consequently, the photocurrent per unit volume remains at a low level contributing to high linearity in the photocurrent. We present the effect of design and lattice patterns of micro/nanostructures on the linearity of ultra-fast silicon PDs designed for high speed multi gigabit data networks.

Multi-level storage and ultra-high speed of superlattice-like Ge50Te50/Ge8Sb92 thin film for phase-change memory application.

Science.gov (United States)

Wu, Weihua; Chen, Shiyu; Zhai, Jiwei; Liu, Xinyi; Lai, Tianshu; Song, Sannian; Song, Zhitang

2017-10-06

Superlattice-like Ge 50 Te 50 /Ge 8 Sb 92 (SLL GT/GS) thin film was systematically investigated for multi-level storage and ultra-fast switching phase-change memory application. In situ resistance measurement indicates that SLL GT/GS thin film exhibits two distinct resistance steps with elevated temperature. The thermal stability of the amorphous state and intermediate state were evaluated with the Kissinger and Arrhenius plots. The phase-structure evolution revealed that the amorphous SLL GT/GS thin film crystallized into rhombohedral Sb phase first, then the rhombohedral GeTe phase. The microstructure, layered structure, and interface stability of SLL GT/GS thin film was confirmed by using transmission electron microscopy. The transition speed of crystallization and amorphization was measured by the picosecond laser pump-probe system. The volume variation during the crystallization was obtained from x-ray reflectivity. Phase-change memory (PCM) cells based on SLL GT/GS thin film were fabricated to verify the multi-level switching under an electrical pulse as short as 30 ns. These results illustrate that the SLL GT/GS thin film has great potentiality in high-density and high-speed PCM applications.

Ultra high energy gamma-ray astronomy

International Nuclear Information System (INIS)

Wdowczyk, J.

1986-01-01

The experimental data on ultra high energy γ-rays are reviewed and a comparison of the properties of photon and proton initiated shower is made. The consequences of the existence of the strong ultra high energy γ-ray sources for other observations is analysed and possible mechanisms for the production of ultra high energy γ-rays in the sources are discussed. It is demonstrated that if the γ-rays are produced via cosmic ray interactions the sources have to produce very high fluxes of cosmic ray particles. In fact it is possible that a small number of such sources can supply the whole Galactic cosmic ray flux

High-speed stimulated Brillouin scattering spectroscopy at 780 nm

Directory of Open Access Journals (Sweden)

Itay Remer

2016-09-01

Full Text Available We demonstrate a high-speed stimulated Brillouin scattering (SBS spectroscopy system that is able to acquire stimulated Brillouin gain point-spectra in water samples and Intralipid tissue phantoms over 2 GHz within 10 ms and 100 ms, respectively, showing a 10-100 fold increase in acquisition rates over current frequency-domain SBS spectrometers. This improvement was accomplished by integrating an ultra-narrowband hot rubidium-85 vapor notch filter in a simplified frequency-domain SBS spectrometer comprising nearly counter-propagating continuous-wave pump-probe light at 780 nm and conventional single-modulation lock-in detection. The optical notch filter significantly suppressed stray pump light, enabling detection of stimulated Brillouin gain spectra with substantially improved acquisition times at adequate signal-to-noise ratios (∼25 dB in water samples and ∼15 dB in tissue phantoms. These results represent an important step towards the use of SBS spectroscopy for high-speed measurements of Brillouin gain resonances in scattering and non-scattering samples.

Magnetically-focusing biochip structures for high-speed active biosensing with improved selectivity

Science.gov (United States)

Yoo, Haneul; Lee, Dong Jun; Kim, Daesan; Park, Juhun; Chen, Xing; Hong, Seunghun

2018-06-01

We report a magnetically-focusing biochip structure enabling a single layered magnetic trap-and-release cycle for biosensors with an improved detection speed and selectivity. Here, magnetic beads functionalized with specific receptor molecules were utilized to trap target molecules in a solution and transport actively to and away from the sensor surfaces to enhance the detection speed and reduce the non-specific bindings, respectively. Using our method, we demonstrated the high speed detection of IL-13 antigens with the improved detection speed by more than an order of magnitude. Furthermore, the release step in our method was found to reduce the non-specific bindings and improve the selectivity and sensitivity of biosensors. This method is a simple but powerful strategy and should open up various applications such as ultra-fast biosensors for point-of-care services.

Decrease of FIB-induced lateral damage for diamond tool used in nano cutting

Energy Technology Data Exchange (ETDEWEB)

Wu, Wei [State Key Laboratory of Precision Measuring Technology and Instruments, Centre of MicroNano Manufacturing Technology, Tianjin University, Tianjin 300072 (China); Xu, Zongwei, E-mail: zongweixu@163.com [State Key Laboratory of Precision Measuring Technology and Instruments, Centre of MicroNano Manufacturing Technology, Tianjin University, Tianjin 300072 (China); Fang, Fengzhou, E-mail: fzfang@gmail.com [State Key Laboratory of Precision Measuring Technology and Instruments, Centre of MicroNano Manufacturing Technology, Tianjin University, Tianjin 300072 (China); Liu, Bing; Xiao, Yinjing; Chen, Jinping [State Key Laboratory of Precision Measuring Technology and Instruments, Centre of MicroNano Manufacturing Technology, Tianjin University, Tianjin 300072 (China); Wang, Xibin [School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081 (China); Liu, Hongzhong [State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049 (China)

2014-07-01

Highlights: • We mainly aim to characterize and decrease the FIB-induced damage on diamond tool. • Raman and XPS methods were used to characterize the nanoscale FIB-induced damage. • Lower energy FIB can effectively lessen the FIB-induced damage on diamond tool. • The diamond tools’ performance was greatly improved after FIB process optimization. • 6 nm chip thickness of copper was achieved by diamond tool with 22 nm edge radius. - Abstract: Diamond cutting tools with nanometric edge radius used in ultra-precision machining can be fabricated by focused ion beam (FIB) technology. However, due to the nanoscale effects, the diamond tools performance and the cutting edge lifetime in nano cutting would be degraded because of the FIB-induced nanoscale lateral damage. In this study, the methods of how to effectively characterize and decrease the FIB-induced lateral damage for diamond tool are intensively studied. Based on the performance optimization diamond machining tools, the controllable chip thickness of less than 10 nm was achieved on a single-crystal copper in nano cutting. In addition, the ratio of minimum thickness of chip (MTC) to tool edge radius of around 0.3–0.4 in nano cutting is achieved. Methods for decreasing the FIB-induced damage on diamond tools and adding coolant during the nano cutting are very beneficial in improving the research of nano cutting and MTC. The nano cutting experiments based on the sharp and high performance of diamond tools would validate the nano cutting mechanisms that many molecular dynamic simulation studies have put forward and provide new findings for nano cutting.

Engineered diamond nanopillars as mobile probes for high sensitivity metrology in fluid

Science.gov (United States)

Andrich, P.; de Las Casas, C. F.; Heremans, F. J.; Awschalom, D. D.; Aleman, B. J.; Ohno, K.; Lee, J. C.; Hu, E. L.

2015-03-01

The nitrogen-vacancy (NV) center`s optical addressability and exceptional spin coherence properties at room temperature, along with diamond`s biocompatibility, has put this defect at the frontier of metrology applications in biological environments. To push the spatial resolution to the nanoscale, extensive research efforts focus on using NV centers embedded in nanodiamonds (NDs). However, this approach has been hindered by degraded spin coherence properties in NDs and the lack of a platform for spatial control of the nanoparticles in fluid. In this work, we combine the use of high quality diamond membranes with a top-down patterning technique to fabricate diamond nanoparticles with engineered and highly reproducible shape, size, and NV center density. We obtain NDs, easily releasable from the substrate into a water suspension, which contain single NV centers exhibiting consistently long spin coherence times (up to 700 μs). Additionally, we demonstrate highly stable, three-dimensional optical trapping of the nanoparticles within a microfluidic circuit. This level of control enables a bulk-like DC magnetic sensitivity and gives access to dynamical decoupling techniques on contactless, miniaturized diamond probes. This work was supported by DARPA, AFOSR, and the DIAMANT program.

Structural modifications of ultra-high molecular weight polyethylene (UHMWPE) processed in attritor type mill

International Nuclear Information System (INIS)

Gabriel, Melina C.; Carvalho, Benjamim de M.; Pinheiro, Luis A.; Cintho, Osvaldo M.; Capocchi, Jose D.T.; Kubaski, Evaldo T.

2009-01-01

Ultra-high molecular weight polyethylene (UHMWPE) is a polyethylene that has a high melt viscosity, hence its processing becomes very difficult. High-energy mechanical milling provides physical and chemical changes in polymers that have been studied recently. In order to study these changes in UHMWPE, powder of this polymer was mechanical milled in attritor type mill with a ball-to-powder weight ratio of 40:1 for 8 hours, varying the rotation speed: 200, 300, 400, 500 e 600 rpm. The polymer was characterized by scanning electron microscopy (SEM) and xray diffraction (XRD). From the XRD results it was noted that as the rotation speed increased the monoclinic phase also increased up to 500 rpm. For 600 rpm, the amount of monoclinic phase apparently decreased. At this rotation speed, the deformation rate probably increased the process temperature, allowing the monoclinic phase to return to its initial structural orthorhombic form. (author)

Diamond bio electronics.

Science.gov (United States)

Linares, Robert; Doering, Patrick; Linares, Bryant

2009-01-01

The use of diamond for advanced applications has been the dream of mankind for centuries. Until recently this dream has been realized only in the use of diamond for gemstones and abrasive applications where tons of diamonds are used on an annual basis. Diamond is the material system of choice for many applications, but its use has historically been limited due to the small size, high cost, and inconsistent (and typically poor) quality of available diamond materials until recently. The recent development of high quality, single crystal diamond crystal growth via the Chemical Vapor Deposition (CVD) process has allowed physcists and increasingly scientists in the life science area to think beyond these limitations and envision how diamond may be used in advanced applications ranging from quantum computing, to power generation and molecular imaging, and eventually even diamond nano-bots. Because of diamond's unique properties as a bio-compatible material, better understanding of diamond's quantum effects and a convergence of mass production, semiconductor-like fabrication process, diamond now promises a unique and powerful key to the realization of the bio-electronic devices being envisioned for the new era of medical science. The combination of robust in-the-body diamond based sensors, coupled with smart bio-functionalized diamond devices may lead to diamond being the platform of choice for bio-electronics. This generation of diamond based bio-electronic devices would contribute substantially to ushering in a paradigm shift for medical science, leading to vastly improved patient diagnosis, decrease of drug development costs and risks, and improved effectiveness of drug delivery and gene therapy programs through better timed and more customized solutions.

Experimental Investigation of Magnetic Superconducting and other Phase Transitions in Novel f-Electron Materials at Ultra-high Pressures using Designer Diamond Anvils

International Nuclear Information System (INIS)

Maple, M. Brian; Jeffries, Jason R.; Ho, Pei-Chun; Butch, Nicholas P.

2004-01-01

Pressure is often used as a controlled parameter for the investigation of condensed matter systems. In particular, pressure experiments can provide valuable information into the nature of superconductivity, magnetism, and the coexistence of these two phenomena. Some f-electron, heavy-fermion materials display interesting and novel behavior at moderately low pressures achievable with conventional experimental techniques; however, a growing number of condensed matter systems require ultrahigh pressure techniques, techniques that generate significantly higher pressures than conventional methods, to sufficiently explore their important properties. To that end, we have been funded to develop an ultrahigh pressure diamond anvil cell facility at the University of California, San Diego (UCSD) in order to investigate superconductivity, magnetism, non-Fermi liquid behavior, and other phenomena. Our goals for the first year of this grant were as follows: (a) set up and test a suitable refrigerator; (b) set up a laser and spectrometer fluorescence system to determine the pressure within the diamond anvil cell; (c) perform initial resistivity measurements at moderate pressures from room temperature to liquid helium temperatures (∼1K); (d) investigate f-electron materials within our current pressure capabilities to find candidate materials for high-pressure studies. During the past year, we have ordered almost all the components required to set up a diamond anvil cell facility at UCSD, we have received and implemented many of the components that have been ordered, we have performed low pressure research on several materials, and we have engaged in a collaborative effort with Sam Weir at Lawrence Livermore National Lab (LLNL) to investigate Au4V under ultrahigh pressure in a designer diamond anvil cell (dDAC). This report serves to highlight the progress we have made towards developing an ultrahigh pressure research facility at UCSD, the research performed in the past year, as

Diamonds on Diamond: structural studies at extreme conditions on the Diamond Light Source.

Science.gov (United States)

McMahon, M I

2015-03-06

Extreme conditions (EC) research investigates how the structures and physical and chemical properties of materials change when subjected to extremes of pressure and temperature. Pressures in excess of one million times atmospheric pressure can be achieved using a diamond anvil cell, and, in combination with high-energy, micro-focused radiation from a third-generation synchrotron such as Diamond, detailed structural information can be obtained using either powder or single-crystal diffraction techniques. Here, I summarize some of the research drivers behind international EC research, and then briefly describe the techniques by which high-quality diffraction data are obtained. I then highlight the breadth of EC research possible on Diamond by summarizing four examples from work conducted on the I15 and I19 beamlines, including a study which resulted in the first research paper from Diamond. Finally, I look to the future, and speculate as to the type of EC research might be conducted at Diamond over the next 10 years. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Do ultra-orphan medicinal products warrant ultra-high prices? A review

Directory of Open Access Journals (Sweden)

Picavet E

2013-06-01

Full Text Available Eline Picavet,1 David Cassiman,2 Steven Simoens1 1Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium; 2Department of Hepatology, University Hospital Leuven, Leuven, Belgium Abstract: Ultra-orphan medicinal products (ultra-OMPs are intended for the treatment, prevention, or diagnosis of ultra-rare diseases, ie, life-threatening or chronically debilitating diseases that affect less than one per 50,000 individuals. Recently, high prices for ultra-OMPs have given rise to debate on the sustainability and justification of these prices. The aim of this article is to review the international scientific literature on the pricing of ultra-OMPs and to provide an overview of the current knowledge on the drivers of ultra-OMP pricing. The pricing process of ultra-OMPs is a complex and nontransparent issue. Evidence in the literature seems to indicate that ultra-OMPs are priced according to rarity and what the manufacturer believes the market will bear. Additionally, there appears to be a trend between the price of an ultra-OMP and the number of available alternatives. Patients, third-party payers, and pharmaceutical companies could benefit from more transparent pricing strategies. With a view to containing health care costs, it is likely that cost-sharing strategies, such as performance-based risk sharing arrangements, will become increasingly more important. However, it is vital that any measures for price control are consistent with the intended goals of the incentives to promote the development of new OMPs. Ideally, a balance must be struck between attaining affordable prices for ultra-OMPs and securing a realistic return on investment for the pharmaceutical industry. Keywords: ultra-orphan medicinal product, ultra-rare disease, pricing

Tracking with CVD diamond radiation sensors at high luminosity colliders (1999-3.1507)

CERN Document Server

Schnetzer, S R; Bauer, C; Berdermann, E; Bergonzo, P; Bogani, F; Borchi, E; Brambilla, A; Bruzzi, Mara; Colledani, C; Conway, J; Dabrowski, W; Da Graca, J; Delpierre, P A; Deneuville, A; Dulinski, W; van Eijk, B; Fallou, A; Fizzotti, F; Foulon, F; Friedl, M; Gan, K K; Gheeraert, E; Grigoriev, E; Hallewell, G D; Hall-Wilton, R; Han, S; Hartjes, F G; Hrubec, Josef; Husson, D; Jamieson, D; Kagan, H; Kania, D R; Kaplon, J; Karl, C; Kass, R; Knöpfle, K T; Krammer, Manfred; Lo Giudice, A; Lü, R; Manfredi, P F; Manfredotti, C; Marshall, R D; Meier, D; Mishina, M; Oh, A; Pan, L S; Palmieri, V G; Pernicka, Manfred; Peitz, A; Pirollo, S; Plano, R J; Polesello, P; Prawer, S; Pretzl, Klaus P; Procario, M; Re, V; Riester, J L; Roe, S; Roff, D G; Rudge, A; Runólfsson, O; Russ, J; Sciortino, S; Somalwar, S V; Speziali, V; Stelzer, H; Stone, R; Suter, B; Tapper, R J; Tesarek, R J; Thomson, G B; Trawick, M L; Trischuk, W; Vittone, E; Walsh, A M; Wedenig, R; Weilhammer, Peter; White, C; Ziock, H J; Zöller, M

1999-01-01

Recent progress on developing diamond-based sensors for vertex detection at high luminosity hadron colliders is described. Measurements of the performance of diamond sensors after irradiation to fluences of up to 5*10/sup 15/ hadrons/cm/sup 2/ are shown. These indicate that diamond sensors will operate at distances as close as 5 cm from the interaction point at the Large Hadron Collider (LHC) for many years at full luminosity without significant degradation in performance. Measurements of the quality of the signals from diamond sensors as well as spatial uniformity are presented. Test beam results on measurements of diamond-based microstrip and pixels devices are described.

Optical Amplication for Terabit-per-Second Ultra-High Speed Communication Systems

DEFF Research Database (Denmark)

Lali-Dastjerdi, Zohreh

The present thesis is concerned with fiber optical parametric amplification and regeneration for high-speed optical communication systems. Fiber optical parametric amplifiers (FOPAs) have multi-functional applications depending on their implementation in optical systems. Based on a few femtosecond...... and saturation effect in order to assess the degradation of the amplified signal. In a very good agreement with the performed experiments, it is shown that the noise transferred to the signal can be effectively suppressed by operating in the saturation regime. The amplification of short few picosecond...

Characterization of a high performance ultra-thin heat pipe cooling module for mobile hand held electronic devices

Science.gov (United States)

Ahamed, Mohammad Shahed; Saito, Yuji; Mashiko, Koichi; Mochizuki, Masataka

2017-11-01

In recent years, heat pipes have been widely used in various hand held mobile electronic devices such as smart phones, tablet PCs, digital cameras. With the development of technology these devices have different user friendly features and applications; which require very high clock speeds of the processor. In general, a high clock speed generates a lot of heat, which needs to be spreaded or removed to eliminate the hot spot on the processor surface. However, it is a challenging task to achieve proper cooling of such electronic devices mentioned above because of their confined spaces and concentrated heat sources. Regarding this challenge, we introduced an ultra-thin heat pipe; this heat pipe consists of a special fiber wick structure named as "Center Fiber Wick" which can provide sufficient vapor space on the both sides of the wick structure. We also developed a cooling module that uses this kind of ultra-thin heat pipe to eliminate the hot spot issue. This cooling module consists of an ultra-thin heat pipe and a metal plate. By changing the width, the flattened thickness and the effective length of the ultra-thin heat pipe, several experiments have been conducted to characterize the thermal properties of the developed cooling module. In addition, other experiments were also conducted to determine the effects of changes in the number of heat pipes in a single module. Characterization and comparison of the module have also been conducted both experimentally and theoretically.

Vibrational spectroscopy at high external pressures the diamond anvil cell

CERN Document Server

Ferraro, John R

1984-01-01

Vibrational Spectroscopy at High External Pressures: The Diamond Anvil Cell presents the effects of high pressure on the vibrational properties of materials as accomplished in a diamond anvil cell (DAC). The DAC serves the dual purpose of generating the pressures and being transparent to infrared radiation, allowing the observation of changes caused by pressure. The optical probes highlighted will deal principally with infrared and Raman scattering, although some observations in the visible region will also be presented. The book begins with a discussion of the effects of pressure and pres

Measurements and Studies of Secondary Electron Emission of Diamond Amplified Photocathode

Energy Technology Data Exchange (ETDEWEB)

Wu,Q.

2008-10-01

The Diamond Amplified Photocathode (DAP) is a novel approach to generating electrons. By following the primary electron beam, which is generated by traditional electron sources, with an amplifier, the electron beam available to the eventual application is increased by 1 to 2 orders of magnitude in current. Diamond has a very wide band gap of 5.47eV which allows for a good negative electron affinity with simple hydrogenation, diamond can hold more than 2000MV/m field before breakdown. Diamond also provides the best rigidity among all materials. These two characters offer the capability of applying high voltage across very thin diamond film to achieve high SEY and desired emission phase. The diamond amplifier also is capable of handling a large heat load by conduction and sub-nanosecond pulse input. The preparation of the diamond amplifier includes thinning and polishing, cleaning with acid etching, metallization, and hydrogenation. The best mechanical polishing available can provide high purity single crystal diamond films with no less than 100 {micro}m thickness and <15 nm Ra surface roughness. The ideal thickness for 700MHz beam is {approx}30 {micro}m, which requires further thinning with RIE or laser ablation. RIE can achieve atomic layer removal precision and roughness eventually, but the time consumption for this procedure is very significant. Laser ablation proved that with <266nm ps laser beam, the ablation process on the diamond can easily achieve removing a few microns per hour from the surface and <100nm roughness. For amplifier application, laser ablation is an adequate and efficient process to make ultra thin diamond wafers following mechanical polishing. Hydrogenation will terminate the diamond surface with monolayer of hydrogen, and form NEA so that secondary electrons in the conduction band can escape into the vacuum. The method is using hydrogen cracker to strike hydrogen atoms onto the bare diamond surface to form H-C bonds. Two independent

Diamond-coated ATR prism for infrared absorption spectroscopy of surface-modified diamond nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Remes, Z., E-mail: remes@fzu.cz [Institute of Physics of the ASCR, v.v.i., Cukrovarnicka 10, Praha 6 (Czech Republic); Kozak, H.; Rezek, B.; Ukraintsev, E.; Babchenko, O.; Kromka, A. [Institute of Physics of the ASCR, v.v.i., Cukrovarnicka 10, Praha 6 (Czech Republic); Girard, H.A.; Arnault, J.-C.; Bergonzo, P. [CEA, LIST, Diamond Sensors Laboratory, F-91191 Gif-sur-Yvette (France)

2013-04-01

Linear antenna microwave chemical vapor deposition process was used to homogeneously coat a 7 cm long silicon prism by 85 nm thin nanocrystalline diamond (NCD) layer. To show the advantages of the NCD-coated prism for attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) of nanoparticles, we apply diamond nanoparticles (DNPs) of 5 nm nominal size with various surface modifications by a drop-casting of their methanol dispersions. ATR-FTIR spectra of as-received, air-annealed, plasma-oxidized, and plasma-hydrogenated DNPs were measured in the 4000–1500 cm{sup −1} spectral range. The spectra show high spectral resolution, high sensitivity to specific DNP surface moieties, and repeatability. The NCD coating provides mechanical protection against scratching and chemical stability of the surface. Moreover, unlike on bare Si surface, NCD hydrophilic properties enable optically homogeneous coverage by DNPs with some aggregation on submicron scale as evidenced by scanning electron microscopy and atomic force microscopy. Compared to transmission FTIR regime with KBr pellets, direct and uniform deposition of DNPs on NCD-ATR prism significantly simplifies and speeds up the analysis (from days to minutes). We discuss prospects for in situ monitoring of surface modifications and molecular grafting.

Diamond-coated ATR prism for infrared absorption spectroscopy of surface-modified diamond nanoparticles

Science.gov (United States)

Remes, Z.; Kozak, H.; Rezek, B.; Ukraintsev, E.; Babchenko, O.; Kromka, A.; Girard, H. A.; Arnault, J.-C.; Bergonzo, P.

2013-04-01

Linear antenna microwave chemical vapor deposition process was used to homogeneously coat a 7 cm long silicon prism by 85 nm thin nanocrystalline diamond (NCD) layer. To show the advantages of the NCD-coated prism for attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) of nanoparticles, we apply diamond nanoparticles (DNPs) of 5 nm nominal size with various surface modifications by a drop-casting of their methanol dispersions. ATR-FTIR spectra of as-received, air-annealed, plasma-oxidized, and plasma-hydrogenated DNPs were measured in the 4000-1500 cm-1 spectral range. The spectra show high spectral resolution, high sensitivity to specific DNP surface moieties, and repeatability. The NCD coating provides mechanical protection against scratching and chemical stability of the surface. Moreover, unlike on bare Si surface, NCD hydrophilic properties enable optically homogeneous coverage by DNPs with some aggregation on submicron scale as evidenced by scanning electron microscopy and atomic force microscopy. Compared to transmission FTIR regime with KBr pellets, direct and uniform deposition of DNPs on NCD-ATR prism significantly simplifies and speeds up the analysis (from days to minutes). We discuss prospects for in situ monitoring of surface modifications and molecular grafting.

ESR studies of high-energy phosphorus-ion implanted synthetic diamond crystals

Energy Technology Data Exchange (ETDEWEB)

Isoya, J [University of Library and Information Science, Tsukuba, Ibaraki (Japan); Kanda, H; Morita, Y; Ohshima, T

1997-03-01

Phosphorus is among potential n-type dopants in diamond. High pressure synthetic diamond crystals of type IIa implanted with high energy (9-18 MeV) phosphorus ions have been studied by using electron spin resonance (ESR) technique. The intensity and the linewidth of the ESR signal attributed to the dangling bond of the amorphous phase varied with the implantation dose, suggesting the nature of the amorphization varies with the dose. The ESR signals of point defects have been observed in the low dose as-implanted crystals and in the high dose crystals annealed at high temperature and at high pressure. (author)

Interfacial effects in ZnO nanotubes/needle-structured graphitic diamond nanohybrid for detecting dissolved acetone at room temperature

Science.gov (United States)

Kathiravan, Deepa; Huang, Bohr-Ran; Saravanan, Adhimoorthy; Yeh, Chien-Jui; Leou, Keh-Chyang; Lin, I.-Nan

2017-12-01

A high-performance ZnO nanotubes (ZNTs)/needle-structured graphitic diamond (NGD) nanohybrid material was prepared and observed the electrochemical sensing properties of liquid acetone in water. Initially, we synthesized NGD film using bias-enhanced growth (BEG) process. Afterwards, a well-etched ZNTs were spatially grown on the NGD film using simple hydrothermal method, and utilized as sensing material for assemble an electrochemical sensor (via EGFET configuration) operating at room temperature. The systematic investigations depict the ultra-high sensing properties attained from ZNTs grown on NGD film. The NGD film mostly have needle or wire shaped diamond grains, which contributes extremely high electrical conductivity. Furthermore, needle shaped diamond grains cover with multi-layer graphitic material generates conduction channels for ZNTs and leads to enhance the oxygen residuals and species. The material stability and conductivity of NGD as well the defects exist with oxygen vacancies in ZNTs offers superior sensing properties. Thus, the interesting combination of these wide band gap semiconductor materials exhibit high sensor response (89 mV/mL), high stability and long-term reliability (tested after 60 days).

Nitrogen aggregation in Ib type synthetic diamonds at low pressure and high-temperature annealing

International Nuclear Information System (INIS)

Kazyuchits, N.M.; Rusetskij, M.S.; Latushko, Ya.I.; Kazyuchits, V.N.; Zajtsev, A.M.

2015-01-01

A new technique for annealing of diamonds at low pressure and high temperature (LPHT) is considered. The absorption spectra of synthetic Ib diamonds are given before and after annealing. This is evident from a comparison of the spectra that nitrogen aggregation process takes place at the LPHT annealing diamond. (authors)

High-Current Cold Cathode Employing Diamond and Related Materials

Energy Technology Data Exchange (ETDEWEB)

Hirshfield, Jay L. [Omega-P, Inc., New Haven, CT (United States)

2014-10-22

The essence of this project was for diamond films to be deposited on cold cathodes to improve their emission properties. Films with varying morphology, composition, and size of the crystals were deposited and the emission properties of the cathodes that utilize such films were studied. The prototype cathodes fabricated by the methods developed during Phase I were tested and evaluated in an actual high-power RF device during Phase II. These high-power tests used the novel active RF pulse compression system and the X-band magnicon test facility at US Naval Research Laboratory. In earlier tests, plasma switches were employed, while tests under this project utilized electron-beam switching. The intense electron beams required in the switches were supplied from cold cathodes embodying diamond films with varying morphology, including uncoated molybdenum cathodes in the preliminary tests. Tests with uncoated molybdenum cathodes produced compressed X-band RF pulses with a peak power of 91 MW, and a maximum power gain of 16.5:1. Tests were also carried out with switches employing diamond coated cathodes. The pulse compressor was based on use of switches employing electron beam triggering to effect mode conversion. In experimental tests, the compressor produced 165 MW in a ~ 20 ns pulse at ~18× power gain and ~ 140 MW at ~ 16× power gain in a 16 ns pulse with a ~ 7 ns flat-top. In these tests, molybdenum blade cathodes with thin diamond coatings demonstrated good reproducible emission uniformity with a 100 kV, 100 ns high voltage pulse. The new compressor does not have the limitations of earlier types of active pulse compressors and can operate at significantly higher electric fields without breakdown.

An Overview of High-k Oxides on Hydrogenated-Diamond for Metal-Oxide-Semiconductor Capacitors and Field-Effect Transistors

Directory of Open Access Journals (Sweden)

Jiangwei Liu

2018-06-01

Full Text Available Thanks to its excellent intrinsic properties, diamond is promising for applications of high-power electronic devices, ultraviolet detectors, biosensors, high-temperature tolerant gas sensors, etc. Here, an overview of high-k oxides on hydrogenated-diamond (H-diamond for metal-oxide-semiconductor (MOS capacitors and MOS field-effect transistors (MOSFETs is demonstrated. Fabrication routines for the H-diamond MOS capacitors and MOSFETs, band configurations of oxide/H-diamond heterointerfaces, and electrical properties of the MOS and MOSFETs are summarized and discussed. High-k oxide insulators are deposited using atomic layer deposition (ALD and sputtering deposition (SD techniques. Electrical properties of the H-diamond MOS capacitors with high-k oxides of ALD-Al2O3, ALD-HfO2, ALD-HfO2/ALD-Al2O3 multilayer, SD-HfO2/ALD-HfO2 bilayer, SD-TiO2/ALD-Al2O3 bilayer, and ALD-TiO2/ALD-Al2O3 bilayer are discussed. Analyses for capacitance-voltage characteristics of them show that there are low fixed and trapped charge densities for the ALD-Al2O3/H-diamond and SD-HfO2/ALD-HfO2/H-diamond MOS capacitors. The k value of 27.2 for the ALD-TiO2/ALD-Al2O3 bilayer is larger than those of the other oxide insulators. Drain-source current versus voltage curves show distinct pitch-off and p-type channel characteristics for the ALD-Al2O3/H-diamond, SD-HfO2/ALD-HfO2/H-diamond, and ALD-TiO2/ALD-Al2O3/H-diamond MOSFETs. Understanding of fabrication routines and electrical properties for the high-k oxide/H-diamond MOS electronic devices is meaningful for the fabrication of high-performance H-diamond MOS capacitor and MOSFET gas sensors.

Towards a Quantum Interface between Diamond Spin Qubits and Phonons in an Optical Trap

Science.gov (United States)

Ji, Peng; Momeen, M. Ummal; Hsu, Jen-Feng; D'Urso, Brian; Dutt, Gurudev

2014-05-01

We introduce a method to optically levitate a pre-selected nanodiamond crystal in air or vacuum. The nanodiamond containing nitrogen-vacancy (NV) centers is suspended on a monolayer of graphene transferred onto a patterned substrate. Laser light is focused onto the sample, using a home-built confocal microscope with a high numerical aperture (NA = 0.9) objective, simultaneously burning the graphene and creating a 3D optical trap that captures the falling nano-diamond at the beam waist. The trapped diamond is an ultra-high-Q mechanical oscillator, allowing us to engineer strong linear and quadratic coupling between the spin of the NV center and the phonon mode. The system could result in an ideal quantum interface between a spin qubit and vibrational phonon mode, potentially enabling applications in quantum information processing and sensing the development of quantum information storage and processing.

Laser machining micro-structures on diamond surface with a sub-nanosecond pulsed laser

Science.gov (United States)

Wu, Mingtao; Guo, Bing; Zhao, Qingliang

2018-02-01

Micro-structure surface on diamond material is widely used in a series of industrial and scientific applications, such as micro-electromechanical systems (MEMS), nanoelectromechanical systems (NEMS), microelectronics, textured or micro-structured diamond machining tools. The efficient machining of micro-structure on diamond surface is urgently demanded in engineering. In this paper, laser machining square micro-structure on diamond surface was studied with a sub-nanosecond pulsed laser. The influences of laser machining parameters, including the laser power, scanning speed, defocusing quantity and scanning pitch, were researched in view of the ablation depth, material removal rate and machined surface topography. Both the ablation depth and material removal rate increased with average laser power. A reduction of the growth rate of the two parameters was induced by the absorption of the laser plasma plume at high laser power. The ablation depth non-linearly decreased with the increasing of the scanning speed while the material removal rate showed an opposite tendency. The increasing of the defocusing quantity induced complex variation of the ablation depth and the material removal rate. The maximum ablation depth and material removal rate were achieved at a defocusing position. The ablation depth and material removal rate oppositely varied about the scanning pitch. A high overlap ratio was meaningful for achieving a smooth micro-structure surface topography. Laser machining with a large defocusing quantity, high laser power and small scanning pitch was helpful for acquiring the desired micro-structure which had a large depth and smooth micro-structure surface topography.

Calculated and experimental low-loss electron energy loss spectra of dislocations in diamond and GaN

CERN Document Server

Jones, R; Gutiérrez-Sosa, A; Bangert, U; Heggie, M I; Blumenau, A T; Frauenheim, T; Briddon, P R

2002-01-01

First-principles calculations of electron energy loss (EEL) spectra for bulk GaN and diamond are compared with experimental spectra acquired with a scanning tunnelling electron microscope offering ultra-high-energy resolution in low-loss energy spectroscopy. The theoretical bulk low-loss EEL spectra, in the E sub g to 10 eV range, are in good agreement with experimental data. Spatially resolved spectra from dislocated regions in both materials are distinct from bulk spectra. The main effects are, however, confined to energy losses lying above the band edge. The calculated spectra for low-energy dislocations in diamond are consistent with the experimental observations, but difficulties remain in understanding the spectra of threading dislocations in GaN.

Comparison of ultra high performance supercritical fluid chromatography, ultra high performance liquid chromatography, and gas chromatography for the separation of synthetic cathinones.

Science.gov (United States)

Carnes, Stephanie; O'Brien, Stacey; Szewczak, Angelica; Tremeau-Cayel, Lauriane; Rowe, Walter F; McCord, Bruce; Lurie, Ira S

2017-09-01

A comparison of ultra high performance supercritical fluid chromatography, ultra high performance liquid chromatography, and gas chromatography for the separation of synthetic cathinones has been conducted. Nine different mixtures of bath salts were analyzed in this study. The three different chromatographic techniques were examined using a general set of controlled synthetic cathinones as well as a variety of other synthetic cathinones that exist as positional isomers. Overall 35 different synthetic cathinones were analyzed. A variety of column types and chromatographic modes were examined for developing each separation. For the ultra high performance supercritical fluid chromatography separations, analyses were performed using a series of Torus and Trefoil columns with either ammonium formate or ammonium hydroxide as additives, and methanol, ethanol or isopropanol organic solvents as modifiers. Ultra high performance liquid chromatographic separations were performed in both reversed phase and hydrophilic interaction chromatographic modes using SPP C18 and SPP HILIC columns. Gas chromatography separations were performed using an Elite-5MS capillary column. The orthogonality of ultra high performance supercritical fluid chromatography, ultra high performance liquid chromatography, and gas chromatography was examined using principal component analysis. For the best overall separation of synthetic cathinones, the use of ultra high performance supercritical fluid chromatography in combination with gas chromatography is recommended. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Boron doped diamond synthesized from detonation nanodiamond in a C-O-H fluid at high pressure and high temperature

Science.gov (United States)

Shakhov, Fedor M.; Abyzov, Andrey M.; Takai, Kazuyuki

2017-12-01

Boron doped diamond (BDD) was synthesized under high pressure and high temperature (HPHT) of 7 GPa, 1230 °C in a short time of 10 s from a powder mixtures of detonation nanodiamond (DND), pentaerythritol C5H8(OH)4 and amorphous boron. SEM, TEM, XRD, XPS, FTIR and Raman spectroscopy indicated that BDD nano- and micro-crystals have formed by consolidation of DND particles (4 nm in size). XRD showed the enlargement of crystallites size to 6-80 nm and the increase in diamond lattice parameter by 0.02-0.07% without appearance of any microstrains. Raman spectroscopy was used to estimate the content of boron atoms embedded in the diamond lattice. It was found that the Raman diamond peak shifts significantly from 1332 cm-1 to 1290 cm-1 without appearance of any non-diamond carbon. The correlation between Raman peak position, its width, and boron content in diamond is proposed. Hydrogenated diamond carbon in significant amount was detected by IR spectroscopy and XPS. Due to the doping with boron content of about 0.1 at%, the electrical conductivity of the diamond achieved approximately 0.2 Ω-1 cm-1. Reaction mechanism of diamond growth (models of recrystallization and oriented attachment) is discussed, including the initial stages of pentaerythritol pyrolysis and thermal desorption of functional groups from the surface of DND particles with the generation of supercritical fluid of low-molecular substances (H2O, CH4, CO, CO2, etc.), as well as byproducts formation (B2O3, B4C).

One step deposition of highly adhesive diamond films on cemented carbide substrates via diamond/β-SiC composite interlayers

Energy Technology Data Exchange (ETDEWEB)

Wang, Tao; Zhuang, Hao; Jiang, Xin, E-mail: xin.jiang@uni-siegen.de

2015-12-30

Graphical abstract: - Highlights: • Novel diamond/beta-silicon carbide composite gradient interlayers were synthesized. • The interlayer features a cross-sectional gradient with increasing diamond content. • Diamond top layers and the interlayers were deposited in one single process. • The adhesion of the diamond film is drastically improved by employing the interlayer. • The stress was suppressed by manipulating the distribution of diamond and silicon carbide. - Abstract: Deposition of adherent diamond films on cobalt-cemented tungsten carbide substrates has been realized by application of diamond/beta-silicon carbide composite interlayers. Diamond top layers and the interlayers were deposited in one single process by hot filament chemical vapor deposition technique. Two different kinds of interlayers have been employed, namely, gradient interlayer and interlayer with constant composition. The distribution of diamond and beta-silicon carbide phases was precisely controlled by manipulating the gas phase composition. X-ray diffraction and Raman spectroscopy were employed to determine the existence of diamond, beta-silicon carbide and cobalt silicides (Co{sub 2}Si, CoSi) phases, as well as the quality of diamond crystal and the residual stress in the films. Rockwell-C indentation tests were carried out to evaluate the film adhesion. It is revealed that the adhesion of the diamond film is drastically improved by employing the interlayer. This is mainly influenced by the residual stress in the diamond top layer, which is induced by the different thermal expansion coefficient of the film and the substrate. It is even possible to further suppress the stress by manipulating the distribution of diamond and beta-silicon carbide in the interlayer. The most adhesive diamond film on cemented carbide is thus obtained by employing a gradient composite interlayer.

Interfacial characteristics of diamond/aluminum composites with high thermal conductivity fabricated by squeeze-casting method

International Nuclear Information System (INIS)

Jiang, Longtao; Wang, Pingping; Xiu, Ziyang; Chen, Guoqin; Lin, Xiu; Dai, Chen; Wu, Gaohui

2015-01-01

In this work, aluminum matrix composites reinforced with diamond particles (diamond/aluminum composites) were fabricated by squeeze casting method. The material exhibited a thermal conductivity as high as 613 W / (m · K). The obtained composites were investigated by scanning electron microscope and transmission electron microscope in terms of the (100) and (111) facets of diamond particles. The diamond particles were observed to be homogeneously distributed in the aluminum matrix. The diamond (111) /Al interface was found to be devoid of reaction products. While at the diamond (100) /Al interface, large-sized aluminum carbides (Al 4 C 3 ) with twin-crystal structure were identified. The interfacial characteristics were believed to be responsible for the excellent thermal conductivity of the material. - Graphical abstract: Display Omitted - Highlights: • Squeeze casting method was introduced to fabricate diamond/Al composite. • Sound interfacial bonding with excellent thermal conductivity was produced. • Diamond (111) / aluminum interface was firstly characterized by TEM/HRTEM. • Physical combination was the controlling bonding for diamond (111) /aluminum. • The growth mechanism of Al 4 C 3 was analyzed by crystallography theory

Thermal applications of low-pressure diamond

International Nuclear Information System (INIS)

Haubner, R.; Lux, B.

1997-01-01

During the last decade several applications of low-pressure diamond were developed. Main products are diamond heat-spreaders using its high thermal conductivity, diamond windows with their high transparency over a wide range of wavelengths and wear resistant tool coatings because of diamonds superhardness. A short description of the most efficient diamond deposition methods (microwave, DC-glow discharge, plasma-jet and arc discharge) is given. The production and applications of diamond layers with high thermal conductivity will be described. Problems of reproducibility of diamond deposition, the influence of impurities, the heat conductivity in electronic packages, reliability and economical mass production will be discussed. (author)

Diamond-coated probe head for measurements in the deep SOL and beyond

DEFF Research Database (Denmark)

Schrittwieser, R.; Xu, G. S.; Yan, Ning

We have tested two cylindrical graphite probe heads coated by a layer of electrically isolating UNCD (Ultra Nano-Crystalline Diamond) using a CVD (Chemical Vapour Deposition) method. The probe heads were mounted on the reciprocating probe manipulator of the Experimental Advanced Superconducting T...

Ultra-high surface speed for metal removal, artillery shell

Science.gov (United States)

Pugh, R. F.; Walsh, M. R.; Pohl, R. F.

1981-07-01

Four types of steel (AISI 1340, 4140, 4340, and HF-1) which are commonly used in large caliber projectile manufacture were machined with five types of tools at different hardness ranges representing the as-forged and the heat-treated condition. Results show that machining speeds can be increased significantly over current practice using the present available tooling.

High-temperature Infrared Transmission of Free-standing Diamond Films

Directory of Open Access Journals (Sweden)

HEI Li-fu

2017-02-01

Full Text Available The combination of low absorption and extreme mechanical and thermal properties make diamond a compelling choice for some more extreme far infrared (8-12 μm window applications. The optical properties of CVD diamond at elevated temperatures are critical to many of these extreme applications. The infrared transmission of free-standing diamond films prepared by DC arc plasma jet were studied at temperature varied conditions. The surface morphology, structure feature and infrared optical properties of diamond films were tested by optical microscope, X-ray diffraction, laser Raman and Fourier-transform infrared spectroscopy. The results show that the average transmittance for 8-12μm is decreased from 65.95% at 27℃ to 52.5% at 500℃,and the transmittance drop is in three stages. Corresponding to the drop of transmittance with the temperature, diamond film absorption coefficient increases with the rise of temperature. The influence of the change of surface state of diamond films on the optical properties of diamond films is significantly greater than the influence on the internal structure.

Ultra high tip speed (670.6 m/sec) fan stage with composite rotor: Aerodynamic and mechanical design

Science.gov (United States)

Halle, J. E.; Burger, G. D.; Dundas, R. E.

1977-01-01

A highly loaded, single-stage compressor having a tip speed of 670.6 m/sec was designed for the purpose of investigating very high tip speeds and high aerodynamic loadings to obtain high stage pressure ratios at acceptable levels of efficiency. The design pressure ratio is 2.8 at an adiabatic efficiency of 84.4%. Corrected design flow is 83.4 kg/sec; corrected design speed is 15,200 rpm; and rotor inlet tip diameter is 0.853 m. The rotor uses multiple-circular-arc airfoils from 0 to 15% span, precompression airfoils assuming single, strong oblique shocks from 21 to 43% span, and precompression airfoils assuming multiple oblique shocks from 52% span to the tip. Because of the high tip speeds, the rotor blades are designed to be fabricated of composite materials. Two composite materials were investigated: Courtaulds HTS graphite fiber in a Kerimid 601 polyimide matrix and the same fibers in a PMR polyimide matrix. In addition to providing a description of the aerodynamic and mechanical design of the 670.0 m/sec fan, discussion is presented of the results of structural tests of blades fabricated with both types of matrices.

Latest Progress in Research on the SpaceLiner High-Speed Passenger Transportation Concept

OpenAIRE

Sippel, Martin; van Foreest, Arnold

2007-01-01

A vision aimed at revolutionizing ultra-long distance travel between different points on earth could be realized by a high-speed intercontinental passenger transport using rocket based, suborbital launchers. The paper gives an overview on the latest progress in conceptual design of the DLR SpaceLiner presenting geometrical size and mass data and describing results of trajectory simulations. The rockets are based on an advanced but technically conservative approach not relying on e...

Sex Difference in Draft-Legal Ultra-Distance Events - A Comparison between Ultra-Swimming and Ultra-Cycling.

Science.gov (United States)

Salihu, Lejla; Rüst, Christoph Alexander; Rosemann, Thomas; Knechtle, Beat

2016-04-30

Recent studies reported that the sex difference in performance in ultra-endurance sports such as swimming and cycling changed over the years. However, the aspect of drafting in draft-legal ultra-endurance races has not yet been investigated. This study investigates the sex difference in ultra-swimming and ultra-cycling draft-legal races where drafting - swimming or cycling behind other participants to save energy and have more power at the end of the race to overtake them, is allowed. The change in performance of the annual best and the annual three best in an ultra-endurance swimming race (16-km 'Faros Swim Marathon') over 38 years and in a 24-h ultra-cycling race ('World Cycling Race') over 13 years were compared and analysed with respect to sex difference. Furthermore, performances of the fastest female and male finishers ever were compared. In the swimming event, the sex difference of the annual best male and female decreased non-significantly (P = 0.262) from 5.3% (1976) to 1.0% (2013). The sex gap of speed in the annual three fastest swimmers decreased significantly (P = 0.043) from 5.9 ± 1.6% (1979) to 4.7 ± 3.1% (2013). In the cycling event, the difference in cycling speed between the annual best male and female decreased significantly (P = 0.026) from 33.31% (1999) to 10.89% (2011). The sex gap of speed in the annual three fastest decreased significantly (P = 0.001) from 32.9 ± 0.6% (1999) to 16.4 ± 5.9% (2011). The fastest male swimmer ever (swimming speed 5.3 km/h, race time: 03:01:55 h:min:s) was 1.5% faster than the fastest female swimmer (swimming speed 5.2 km/h, race time: 03:04:09 h:min:s). The three fastest male swimmers ever (mean 5.27 ± 0.13 km/h) were 4.4% faster than the three fastest female swimmers (mean 5.05 ± 0.20 km/h) (P swimming and cycling, the sex difference in the annual top and annual top three swimmers and cyclists decreased (i.e. non-linearly in swimmers and linearly in cyclists) over the years. The sex difference of the

High Q diamond hemispherical resonators: fabrication and energy loss mechanisms

International Nuclear Information System (INIS)

Bernstein, Jonathan J; Bancu, Mirela G; Bauer, Joseph M; Cook, Eugene H; Kumar, Parshant; Nyinjee, Tenzin; Perlin, Gayatri E; Ricker, Joseph A; Teynor, William A; Weinberg, Marc S; Newton, Eric

2015-01-01

We have fabricated polycrystalline diamond hemispheres by hot-filament CVD (HFCVD) in spherical cavities wet-etched into a high temperature glass substrate CTE matched to silicon. Hemispherical resonators 1.4 mm in diameter have a Q of up to 143 000 in the fundamental wineglass mode, for a ringdown time of 2.4 s. Without trimming, resonators have the two degenerate wineglass modes frequency matched as close as 2 Hz, or 0.013% of the resonant frequency (∼16 kHz). Laser trimming was used to match resonant modes on hemispheres to 0.3 Hz. Experimental and FEA energy loss studies on cantilevers and hemispheres examine various energy loss mechanisms, showing that surface related losses are dominant. Diamond cantilevers with a Q of 400 000 and a ringdown time of 15.4 s were measured, showing the potential of polycrystalline diamond films for high Q resonators. These resonators show great promise for use as hemispherical resonant gyroscopes (HRGs) on a chip. (paper)

Toward deep blue nano hope diamonds: heavily boron-doped diamond nanoparticles.

Science.gov (United States)

Heyer, Steffen; Janssen, Wiebke; Turner, Stuart; Lu, Ying-Gang; Yeap, Weng Siang; Verbeeck, Jo; Haenen, Ken; Krueger, Anke

2014-06-24

The production of boron-doped diamond nanoparticles enables the application of this material for a broad range of fields, such as electrochemistry, thermal management, and fundamental superconductivity research. Here we present the production of highly boron-doped diamond nanoparticles using boron-doped CVD diamond films as a starting material. In a multistep milling process followed by purification and surface oxidation we obtained diamond nanoparticles of 10-60 nm with a boron content of approximately 2.3 × 10(21) cm(-3). Aberration-corrected HRTEM reveals the presence of defects within individual diamond grains, as well as a very thin nondiamond carbon layer at the particle surface. The boron K-edge electron energy-loss near-edge fine structure demonstrates that the B atoms are tetrahedrally embedded into the diamond lattice. The boron-doped diamond nanoparticles have been used to nucleate growth of a boron-doped diamond film by CVD that does not contain an insulating seeding layer.

Nanostructured diamond film deposition on curved surfaces of metallic temporomandibular joint implant

Energy Technology Data Exchange (ETDEWEB)

Fries, Marc D; Vohra, Yogesh K [Department of Physics, University of Alabama at Birmingham (UAB), Birmingham, AL (United States)

2002-10-21

Microwave plasma chemical vapour deposition of nanostructured diamond films was carried out on curved surfaces of Ti-6Al-4V alloy machined to simulate the shape of a temporomandibular joint (TMJ) dental implant. Raman spectroscopy shows that the deposited films are uniform in chemical composition along the radius of curvature of the TMJ condyle. Thin film x-ray diffraction reveals an interfacial carbide layer and nanocrystalline diamond grains in this coating. Nanoindentation hardness measurements show an ultra-hard coating with a hardness value of 60{+-}5 GPa averaged over three samples. (rapid communication)

Diamond turning of thermoplastic polymers

Energy Technology Data Exchange (ETDEWEB)

Smith, E.; Scattergood, R.O.

1988-12-01

Single point diamond turning studies were made using a series of thermoplastic polymers with different glass transition temperatures. Variations in surface morphology and surface roughness were observed as a function of cutting speed. Lower glass transition temperatures facilitate smoother surface cuts and better surface finish. This can be attributed to the frictional heating that occurs during machining. Because of the very low glass transition temperatures in polymeric compared to inorganic glasses, the precision machining response can be very speed sensitive.

High speed atom source

International Nuclear Information System (INIS)

Hoshino, Hitoshi.

1990-01-01

In a high speed atom source, since the speed is not identical between ions and electrons, no sufficient neutralizing effect for ionic rays due to the mixing of the ionic rays and the electron rays can be obtained failing to obtain high speed atomic rays at high density. In view of the above, a speed control means is disposed for equalizing the speed of ions forming ionic rays and the speed of electrons forming electron rays. Further, incident angle of the electron rays and/or ionic rays to a magnet or an electrode is made variable. As a result, the relative speed between the ions and the electrons to the processing direction is reduced to zero, in which the probability of association between the ions and the electrons due to the coulomb force is increased to improve the neutralizing efficiency to easily obtain fine and high density high speed electron rays. Further, by varying the incident angle, a track capable of obtaining an ideal mixing depending on the energy of the neutralized ionic rays is formed. Since the high speed electron rays has such high density, they can be irradiated easily to the minute region of the specimen. (N.H.)

Interfacial characteristics of diamond/aluminum composites with high thermal conductivity fabricated by squeeze-casting method

Energy Technology Data Exchange (ETDEWEB)

Jiang, Longtao, E-mail: longtaojiang@163.com [Department of Material Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Wang, Pingping [Department of Material Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Xiu, Ziyang [Skate Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Chen, Guoqin [Department of Material Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Lin, Xiu [Heilongjiang Academy of Industrial Technology, Harbin 150001 (China); Dai, Chen; Wu, Gaohui [Department of Material Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)

2015-08-15

In this work, aluminum matrix composites reinforced with diamond particles (diamond/aluminum composites) were fabricated by squeeze casting method. The material exhibited a thermal conductivity as high as 613 W / (m · K). The obtained composites were investigated by scanning electron microscope and transmission electron microscope in terms of the (100) and (111) facets of diamond particles. The diamond particles were observed to be homogeneously distributed in the aluminum matrix. The diamond{sub (111)}/Al interface was found to be devoid of reaction products. While at the diamond{sub (100)}/Al interface, large-sized aluminum carbides (Al{sub 4}C{sub 3}) with twin-crystal structure were identified. The interfacial characteristics were believed to be responsible for the excellent thermal conductivity of the material. - Graphical abstract: Display Omitted - Highlights: • Squeeze casting method was introduced to fabricate diamond/Al composite. • Sound interfacial bonding with excellent thermal conductivity was produced. • Diamond{sub (111)}/ aluminum interface was firstly characterized by TEM/HRTEM. • Physical combination was the controlling bonding for diamond{sub (111)}/aluminum. • The growth mechanism of Al{sub 4}C{sub 3} was analyzed by crystallography theory.

Quantitative assessment of the enamel machinability in tooth preparation with dental diamond burs.

Science.gov (United States)

Song, Xiao-Fei; Jin, Chen-Xin; Yin, Ling

2015-01-01

Enamel cutting using dental handpieces is a critical process in tooth preparation for dental restorations and treatment but the machinability of enamel is poorly understood. This paper reports on the first quantitative assessment of the enamel machinability using computer-assisted numerical control, high-speed data acquisition, and force sensing systems. The enamel machinability in terms of cutting forces, force ratio, cutting torque, cutting speed and specific cutting energy were characterized in relation to enamel surface orientation, specific material removal rate and diamond bur grit size. The results show that enamel surface orientation, specific material removal rate and diamond bur grit size critically affected the enamel cutting capability. Cutting buccal/lingual surfaces resulted in significantly higher tangential and normal forces, torques and specific energy (pmachinability for clinical dental practice. Copyright © 2014 Elsevier Ltd. All rights reserved.

A novel Mo-W interlayer approach for CVD diamond deposition on steel

Science.gov (United States)

Kundrát, Vojtěch; Zhang, Xiaoling; Cooke, Kevin; Sun, Hailin; Sullivan, John; Ye, Haitao

2015-04-01

Steel is the most widely used material in engineering for its cost/performance ratio and coatings are routinely applied on its surface to further improve its properties. Diamond coated steel parts are an option for many demanding industrial applications through prolonging the lifetime of steel parts, enhancement of tool performance as well as the reduction of wear rates. Direct deposition of diamond on steel using conventional chemical vapour deposition (CVD) processes is known to give poor results due to the preferential formation of amorphous carbon on iron, nickel and other elements as well as stresses induced from the significant difference in the thermal expansion coefficients of those materials. This article reports a novel approach of deposition of nanocrystalline diamond coatings on high-speed steel (M42) substrates using a multi-structured molybdenum (Mo) - tungsten (W) interlayer to form steel/Mo/Mo-W/W/diamond sandwich structures which overcome the adhesion problem related to direct magnetron sputtering deposition of pure tungsten. Surface, interface and tribology properties were evaluated to understand the role of such an interlayer structure. The multi-structured Mo-W interlayer has been proven to improve the adhesion between diamond films and steel substrates by acting as an effective diffusion barrier during the CVD diamond deposition.

A novel Mo-W interlayer approach for CVD diamond deposition on steel

Energy Technology Data Exchange (ETDEWEB)

Kundrát, Vojtěch; Sullivan, John; Ye, Haitao, E-mail: h.ye@aston.ac.uk [School of Engineering and Applied Science, Aston University, Birmingham, B4 7ET (United Kingdom); Zhang, Xiaoling; Cooke, Kevin; Sun, Hailin [Miba Coating Group: Teer Coatings Ltd, West-Stone-House, West-Stone, Berry-Hill-Industrial-Estate, WR9 9AS, Droitwich (United Kingdom)

2015-04-15

Steel is the most widely used material in engineering for its cost/performance ratio and coatings are routinely applied on its surface to further improve its properties. Diamond coated steel parts are an option for many demanding industrial applications through prolonging the lifetime of steel parts, enhancement of tool performance as well as the reduction of wear rates. Direct deposition of diamond on steel using conventional chemical vapour deposition (CVD) processes is known to give poor results due to the preferential formation of amorphous carbon on iron, nickel and other elements as well as stresses induced from the significant difference in the thermal expansion coefficients of those materials. This article reports a novel approach of deposition of nanocrystalline diamond coatings on high-speed steel (M42) substrates using a multi-structured molybdenum (Mo) – tungsten (W) interlayer to form steel/Mo/Mo-W/W/diamond sandwich structures which overcome the adhesion problem related to direct magnetron sputtering deposition of pure tungsten. Surface, interface and tribology properties were evaluated to understand the role of such an interlayer structure. The multi-structured Mo-W interlayer has been proven to improve the adhesion between diamond films and steel substrates by acting as an effective diffusion barrier during the CVD diamond deposition.

A novel Mo-W interlayer approach for CVD diamond deposition on steel

Directory of Open Access Journals (Sweden)

Vojtěch Kundrát

2015-04-01

Full Text Available Steel is the most widely used material in engineering for its cost/performance ratio and coatings are routinely applied on its surface to further improve its properties. Diamond coated steel parts are an option for many demanding industrial applications through prolonging the lifetime of steel parts, enhancement of tool performance as well as the reduction of wear rates. Direct deposition of diamond on steel using conventional chemical vapour deposition (CVD processes is known to give poor results due to the preferential formation of amorphous carbon on iron, nickel and other elements as well as stresses induced from the significant difference in the thermal expansion coefficients of those materials. This article reports a novel approach of deposition of nanocrystalline diamond coatings on high-speed steel (M42 substrates using a multi-structured molybdenum (Mo – tungsten (W interlayer to form steel/Mo/Mo-W/W/diamond sandwich structures which overcome the adhesion problem related to direct magnetron sputtering deposition of pure tungsten. Surface, interface and tribology properties were evaluated to understand the role of such an interlayer structure. The multi-structured Mo-W interlayer has been proven to improve the adhesion between diamond films and steel substrates by acting as an effective diffusion barrier during the CVD diamond deposition.

Hydrogen termination of CVD diamond films by high-temperature annealing at atmospheric pressure

NARCIS (Netherlands)

Seshan, V.; Ullien, D.; Castellanos-Gomez, A.; Sachdeva, S.; Murthy, D.H.K.; Savenije, T.J.; Ahmad, H.A.; Nunney, T.S.; Janssens, S.D.; Haenen, K.; Nesládek, M.; Van der Zant, H.S.J.; Sudhölter, E.J.R.; De Smet, L.C.P.M.

2013-01-01

A high-temperature procedure to hydrogenate diamond films using molecular hydrogen at atmospheric pressure was explored. Undoped and doped chemical vapour deposited (CVD) polycrystalline diamond films were treated according to our annealing method using a H2 gas flow down to ?50 ml/min (STP) at

Stretchers and compressors for ultra-high power laser systems

Energy Technology Data Exchange (ETDEWEB)

Yakovlev, I V [Institute of Applied Physics, Russian Academy of Sciences, Nizhnii Novgorod (Russian Federation)

2014-05-30

This review is concerned with pulse stretchers and compressors as key components of ultra-high power laser facilities that take advantage of chirped-pulse amplification. The potentialities, characteristics, configurations and methods for the matching and alignment of these devices are examined, with particular attention to the history of the optics of ultra-short, ultra-intense pulses before and after 1985, when the chirped-pulse amplification method was proposed, which drastically changed the view of the feasibility of creating ultra-high power laser sources. The review is intended primarily for young scientists and experts who begin to address the amplification and compression of chirped pulses, experts in laser optics and all who are interested in scientific achievements in the field of ultra-high power laser systems. (review)

Creation of nitrogen-vacancy centres in diamond with high resolution

Energy Technology Data Exchange (ETDEWEB)

Pezzagna, Sebastien; Meijer, Jan [Rubion, Ruhr-Universitaet Bochum (Germany); Wildanger, Dominik; Hell, Stefan W. [Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, Goettingen (Germany); Mazarov, Paul; Wieck, Andreas D. [Lehrstuhl fuer Angewandte Festkoerperphysik, Ruhr-Universitaet Bochum (Germany); Naydenov, Boris; Jelezko, Fedor; Wrachtrup, Joerg [3. Institute of Physics, University of Stuttgart (Germany)

2010-07-01

Nowadays, diamond and the nitrogen-vacancy (NV) colour centres constitute the best solid-state system in view of quantum-computing applications. It has also been shown recently that single NV centres could be used as nanoscale magnetic sensors. Such applications require the creation of single NV centres with very high resolution and with a high efficiency. The nano-implanter at the university of Bochum provides low energy nitrogen ions which can be implanted through a hole pierced in the tip of an atomic force microscope. Ultrapure diamond samples have been implanted with spot sizes of 50nm and less. Stimulated Emission Depletion (STED) microscopy has been used to characterise and resolve the implanted spots.

ITER ECRH upper launcher torus diamond window – Prototyping, testing and qualification

Energy Technology Data Exchange (ETDEWEB)

Schreck, Sabine, E-mail: sabine.schreck@kit.edu [Karlsruhe Institute of Technology, Institute for Applied Materials, Association KIT-EURATOM, P.O. Box 3640, D-76021 Karlsruhe (Germany); Aiello, Gaetano; Meier, Andreas; Strauss, Dirk [Karlsruhe Institute of Technology, Institute for Applied Materials, Association KIT-EURATOM, P.O. Box 3640, D-76021 Karlsruhe (Germany); Ikeda, Ryosuke; Oda, Yasuhisa; Sakamoto, Keishi; Takahashi, Koji [Japan Atomic Energy Agency (JAEA), Plasma Heating Technology Group, 801-1 Mukoyama, Naka, Ibaraki 311-0193 (Japan); Scherer, Theo [Karlsruhe Institute of Technology, Institute for Applied Materials, Association KIT-EURATOM, P.O. Box 3640, D-76021 Karlsruhe (Germany)

2015-10-15

Highlights: • The diamond window prototype shows a very good transmission capability during high power RF experiments. • An ad-hoc qualification programme for the diamond torus window is being developed (contract between KIT and F4E). • The window design has been updated focused on its mechanical integrity and manufacturing aspects. - Abstract: The diamond window assembly is part of the ITER primary vacuum boundary and acts as the first tritium barrier and therefore it is classified as Safety/Protection Important Component (SIC/PIC). It consists of an ultra-low loss CVD diamond disk mounted in a system of metallic parts (copper/steel) and has to fulfil adequate transmission capability for high power mm-waves. High power RF experiments with a 1st window prototype had shown parasitic heating due to small gaps in the housing. After a design optimization directed to the mm-wave properties, the parasitic excitations of oscillations have been avoided in a 2nd prototype. This one is equipped with inserted waveguide structures, which cover gaps in the metallic structure of the window housing. From high power RF-measurements with a 0.86 MW/100 s pulse a loss tangent of 7.1 × 10{sup −6} could be estimated, corresponding to an increase of temperature of only 120 mK between inlet and outlet of the cooling system. The diamond window assemblies cannot be entirely covered by codes and standards. To comply with the French safety regulations, instead an ad-hoc qualification programme is required, being developed in the framework of a contract between KIT and F4E. A new prototype (3rd) will be built, which is designed to fit to the single HELICOFLEX sealed waveguide structures of the ex-vessel mm-system of the EC upper launcher (UL). The testing programme ranges from mechanical to vacuum tests up to dielectric loss measurements at low and high power. A clear definition of the testing requirements and of the acceptance criteria is necessary as well as a complete

High-speed ultra-wideband wireless signals over fiber systems: Photonic generation and DSP detection

DEFF Research Database (Denmark)

Yu, Xianbin; Gibbon, Timothy Braidwood; Tafur Monroy, Idelfonso

2009-01-01

We firstly review the efforts in the literature on UWB over-fiber systems. Secondly, we present experimental results on photonic generation of high-speed UWB signals by both direct modulation and external optical injecting an uncooled semiconductor laser. Furthermore, we introduce the use of digi...

The gem anvil cell: high-pressure behaviour of diamond and related materials

International Nuclear Information System (INIS)

Xu Jian; Mao Hokwang; Hemley, Russell J

2002-01-01

The moissanite anvil cell has been used to study the high-pressure behaviour of diamond. The first-order Raman shift of diamond shows a strong dependence on hydrostaticity, with very different pressure dependences observed under hydrostatic and non-hydrostatic conditions. The shift of the second-order Raman band under hydrostatic pressures was determined for the first time. Sapphire has almost no peaks above 1000 cm -1 in the Raman spectrum and no absorption in the ultraviolet range; it is therefore especially useful for studies in those spectral regions. A sapphire anvil cell was used in a study of graphite up to 24 GPa. A phase transition was found near 18 GPa, consistent with previous reports, and no peaks characteristic of diamond in the 1330 cm -1 range were found, indicating that the phase is not diamond

The gem anvil cell: high-pressure behaviour of diamond and related materials

CERN Document Server

Xu Jian; Hemley, R J

2002-01-01

The moissanite anvil cell has been used to study the high-pressure behaviour of diamond. The first-order Raman shift of diamond shows a strong dependence on hydrostaticity, with very different pressure dependences observed under hydrostatic and non-hydrostatic conditions. The shift of the second-order Raman band under hydrostatic pressures was determined for the first time. Sapphire has almost no peaks above 1000 cm sup - sup 1 in the Raman spectrum and no absorption in the ultraviolet range; it is therefore especially useful for studies in those spectral regions. A sapphire anvil cell was used in a study of graphite up to 24 GPa. A phase transition was found near 18 GPa, consistent with previous reports, and no peaks characteristic of diamond in the 1330 cm sup - sup 1 range were found, indicating that the phase is not diamond.

High-speed photoacoustic imaging using an LED-based photoacoustic imaging system

Science.gov (United States)

Sato, Naoto; Kuniyil Ajith Singh, Mithun; Shigeta, Yusuke; Hanaoka, Takamitsu; Agano, Toshitaka

2018-02-01

Recently we developed a multispectral LED-based photoacoustic/ultrasound imaging system (AcousticX) and have been continuously working on its technical/functional improvements. AcousticX is a linear array ultrasound transducer (128 elements, 10 MHz)-based system in which LED arrays (selectable wavelengths, pulse repetition frequency: 4 kHz, pulse width: tunable from 40 - 100 ns) are fixed on both sides of the transducer to illuminate the tissue for photoacoustic imaging. The ultrasound/photoacoustic data from all 128 elements can be simultaneously acquired, processed and displayed. We already demonstrated our system's capability to perform photoacoustic/ultrasound imaging for dynamic imaging of the tissue at a frame rate of 10 Hz (for example to visualize the pulsation of arteries in vivo in human subjects). In this work, we present the development of a new high-speed imaging mode in AcousticX. In this mode, instead of toggling between ultrasound and photoacoustic measurements, it is possible to continuously acquire only photoacoustic data for 1.5 seconds with a time interval of 1 ms. With this improvement, we can record photoacoustic signals from the whole aperture (38 mm) at fast rate and can be reviewed later at different speeds for analyzing dynamic changes in the photoacoustic signals. We believe that AcousticX with this new high-speed mode opens up a feasible technical path for multiple dynamic studies, for example one which focus on imaging the response of voltage sensitive dyes. We envisage to improve the acquisition speed further in future for exploring ultra-high-speed applications.

Recent Developments In High Speed Lens Design At The NPRL

Science.gov (United States)

Mcdowell, M. W.; Klee, H. W.

1987-09-01

Although the lens provides the link between the high speed camera and the outside world, there has over the years been little evidence of co-operation between the optical design and high speed photography communities. It is still only too common for a manufacturer to develop a camera of improved performance and resolution and then to combine this with a standard camera lens. These lenses were often designed for a completely different recording medium and, more often than not, their use results in avoidable degradation of the overall system performance. There is a tendency to assume that a specialized lens would be too expensive and that pushing the aperture automatically implies more complex optical systems. In the present paper some recent South African developments in the design of large aperture lenses are described. The application of a new design principle, based on the work earlier this century of Bernhard Schmidt, shows that ultra-fast lenses need not be overly complex and a basic four-element lens configuration can be adapted to a wide variety of applications.

The Development on the Ultra-hard Honing Oilstones in Preparation and Application

Science.gov (United States)

Zhou, Z. C.; Du, J.; Gu, S. Y.

2018-03-01

Physical, chemical and mechanical properties of some abrasives such as diamond, CBN are described in this paper. The preparation and application of ultra-hard oilstones such as diamond and CBN are also discussed. They are widely applied in honing and promote great development of honing technology. However, the standardizing binder compositions of diamond and CBN can not easily obtained. In addition, the precision requisition of grinded parts is different from part to part and the grinded material kinds are diverse. Therefore, the oilstone performance is difficult to match reasonably the grinded parts. Those factors result in the complication of the oilstone preparation.

Machinability of lithium disilicate glass ceramic in in vitro dental diamond bur adjusting process.

Science.gov (United States)

Song, Xiao-Fei; Ren, Hai-Tao; Yin, Ling

2016-01-01

Esthetic high-strength lithium disilicate glass ceramics (LDGC) are used for monolithic crowns and bridges produced in dental CAD/CAM and oral adjusting processes, which machinability affects the restorative quality. A machinability study has been made in the simulated oral clinical machining of LDGC with a dental handpiece and diamond burs, regarding the diamond tool wear and chip control, machining forces and energy, surface finish and integrity. Machining forces, speeds and energy in in vitro dental adjusting of LDGC were measured by a high-speed data acquisition and force sensor system. Machined LDGC surfaces were assessed using three-dimensional non-contact chromatic confocal optical profilometry and scanning electron microscopy (SEM). Diamond bur morphology and LDGC chip shapes were also examined using SEM. Minimum tool wear but significant LDGC chip accumulations were found. Machining forces and energy significantly depended on machining conditions (pceramics (pceramics (pceramics. Surface roughness for machined LDGC was comparable for other glass ceramics. The removal mechanisms of LDGC were dominated by penetration-induced brittle fracture and shear-induced plastic deformation. Unlike most other glass ceramics, distinct intergranular and transgranular fractures of lithium disilicate crystals were found in LDGC. This research provides the fundamental data for dental clinicians on the machinability of LDGC in intraoral adjustments. Copyright © 2015 Elsevier Ltd. All rights reserved.

Influence of chemical pretreatment of hard metal substrates for diamond deposition

International Nuclear Information System (INIS)

Buck, V.; Kluwe, H.; Schmiler, B.; Deuerler, F.

2001-01-01

Diamond coated cutting tools are of increasing importance in the fields of high speed cutting, dry machining or machining of special materials such as metal-matrix-composites. A well known problem is the poor adhesion of diamond films on hard metals due to the Co- or Ni-binder that catalyzes the formation of graphite. Several methods - such as the application of intermediate layers or mechanical or chemical pretreatment of the hard metal substrate - have been developed to overcome this effect. Usually chemical pretreatment is used in order to reduce the concentration of binder phase on the surface that is to be coated. Surprisingly pretreatment with agents such as Murakami's solution result in improved adhesion and nucleation of diamond films while the concentration of the binder phase on the surface is enhanced. This 'contradiction' can be explained by proving that the surface is converted into a very thin oxide/hydroxide film. (author)

Thermochemical micro imprinting of single-crystal diamond surface using a nickel mold under high-pressure conditions

Energy Technology Data Exchange (ETDEWEB)

Imoto, Yuji; Yan, Jiwang, E-mail: yan@mech.keio.ac.jp

2017-05-15

Graphical abstract: A Ni mold and thermochemically imprinted microstructures on diamond. - Highlights: • A thermochemical method for micro machining/patterning of diamond is proposed. • Various kinds of microstructures were imprinted on diamond using a Ni mold. • A graphite layer is formed during imprinting which can be removed by acid. • The processing depth depends strongly on pressure and temperature. - Abstract: Single-crystal diamond is an important material for cutting tools, micro electro mechanical systems, optical devices, and semiconductor substrates. However, the techniques for producing microstructures on diamond surface with high efficiency and accuracy have not been established. This paper proposes a thermochemical imprinting method for transferring microstructures from a nickel (Ni) mold onto single-crystal diamond surface. The Ni mold was micro-structured by a nanoindenter and then pressed against the diamond surface under high temperature and pressure in argon atmosphere. Results show that microstructures on the Ni mold were successfully transferred onto the diamond surface, and their depth increased with both pressure and temperature. Laser micro-Raman spectroscopy, transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS) analyses indicate that a graphite layer was formed over the contact area between diamond and Ni during pressing, and after washing by a mixed acid, the graphite layer could be completely removed. This study demonstrated the feasibility of a cost-efficient fabrication method for large-area microstructures on single-crystal diamond.

Ultra high field magnetic resonance imaging

International Nuclear Information System (INIS)

Lethimonnier, F.; Vedrine, P.

2007-01-01

Understanding human brain function, brain development and brain dysfunction is one of the great challenges of the twenty first century. Biomedical imaging has now run up against a number of technical constraints that are exposing limits to its potential. In order to overcome the current limits to high-field magnetic resonance cerebral imaging (MRI) and unleash its fullest potential, the Cea has built NeuroSpin, an ultra-high-field neuroimaging facility at its Saclay centre (in the Essonne). NeuroSpin already boasts three fully operational MRI systems. The first is a 3-tesla high-field system and the second is a very-high-field 7-tesla system, both of which are dedicated to clinical studies and investigations in humans, while the third is an ultra-high-field 17.65-tesla system designed for studies on small animals. In 2011, NeuroSpin will be commissioning an 11.7-tesla ultra-high-field system of unprecedented power that is designed for research on human subjects. The level of the magnetic field and the scale required will make this joint French-German project to build the magnet a breakthrough in the international arena. (authors)

Diamond and Diamond-Like Materials as Hydrogen Isotope Barriers

International Nuclear Information System (INIS)

Foreman, L.R.; Barbero, R.S.; Carroll, D.W.; Archuleta, T.; Baker, J.; Devlin, D.; Duke, J.; Loemier, D.; Trukla, M.

1999-01-01

This is the final report of a two-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The purpose of this project was to develop diamond and diamond-like thin-films as hydrogen isotope permeation barriers. Hydrogen embrittlement limits the life of boost systems which otherwise might be increased to 25 years with a successful non-reactive barrier. Applications in tritium processing such as bottle filling processes, tritium recovery processes, and target filling processes could benefit from an effective barrier. Diamond-like films used for low permeability shells for ICF and HEDP targets were also investigated. Unacceptable high permeabilities for hydrogen were obtained for plasma-CVD diamond-like-carbon films

Experimental analysis and theoretical model for anomalously high ideality factors in ZnO/diamond p-n junction diode

International Nuclear Information System (INIS)

Wang Chengxin; Yang Guowei; Liu Hongwu; Han Yonghao; Luo Jifeng; Gao Chunxiao; Zou Guangtian

2004-01-01

High-quality heterojunctions between p-type diamond single-crystalline films and highly oriented n-type ZnO films were fabricated by depositing the p-type diamond single-crystal films on the I o -type diamond single crystal using a hot filament chemical vapor deposition, and later growing a highly oriented n-type ZnO film on the p-type diamond single-crystal film by magnetron sputtering. Interestingly, anomalously high ideality factors (n>>2.0) in the prepared ZnO/diamond p-n junction diode in the interim bias voltage range were measured. For this, detailed electronic characterizations of the fabricated p-n junction were conducted, and a theoretical model was proposed to clarify the much higher ideality factors of the special heterojunction diode

Diamond: a material for acoustic devices

OpenAIRE

MORTET, Vincent; WILLIAMS, Oliver; HAENEN, Ken

2008-01-01

Diamond has been foreseen to replace silicon for high power, high frequency electronic applications or for devices that operates in harsh environments. However, diamond electronic devices are still in the laboratory stage due to the lack of large substrates and the complexity of diamond doping. On another hand, surface acoustic wave filters based on diamond are commercially available. Diamond is especially suited for acoustic applications because of its exceptional mechanical properties. The ...

Towards freeform curved blazed gratings using diamond machining

Science.gov (United States)

Bourgenot, C.; Robertson, D. J.; Stelter, D.; Eikenberry, S.

2016-07-01

Concave blazed gratings greatly simplify the architecture of spectrographs by reducing the number of optical components. The production of these gratings using diamond-machining offers practically no limits in the design of the grating substrate shape, with the possibility of making large sag freeform surfaces unlike the alternative and traditional method of holography and ion etching. In this paper, we report on the technological challenges and progress in the making of these curved blazed gratings using an ultra-high precision 5 axes Moore-Nanotech machine. We describe their implementation in an integral field unit prototype called IGIS (Integrated Grating Imaging Spectrograph) where freeform curved gratings are used as pupil mirrors. The goal is to develop the technologies for the production of the next generation of low-cost, compact, high performance integral field unit spectrometers.

Near-infrared refractive index of synthetic single crystal and polycrystalline diamonds at high temperatures

Science.gov (United States)

Yurov, V. Yu.; Bushuev, E. V.; Popovich, A. F.; Bolshakov, A. P.; Ashkinazi, E. E.; Ralchenko, V. G.

2017-12-01

We measured the refractive index n(T) and thermo-optical coefficient β(T) = (1/n)(dn/dT) of high quality synthetic diamonds from room temperature to high temperatures, up to 1520 K, in near-infrared spectral range at wavelength 1.56 μm, using a low-coherence interferometry. A type IIa single crystal diamond produced by high pressure-high temperature technique and a transparent polycrystalline diamond grown by chemical vapor deposition were tested and revealed a very close n(T) behavior, with n = 2.384 ± 0.001 at T = 300 K, monotonically increasing to 2.428 at 1520 K. The n(T) data corrected to thermal expansion of diamond are well fitted with 3rd order polynomials, and alternatively, with the Bose-Einstein model with an effective oscillator frequency of 970 cm-1. Almost linear n(T) dependence is observed above 800 K. The thermo-optical coefficient is found to increase monotonically from (0.6 ± 0.1) × 10-5 K-1 (300 K) to (2.0 ± 0.1) × 10-5 K-1 (1300 K) with a tendency to saturation at >1200 K. These β(T) values are an order of magnitude lower than those known for Si, GaAs, and InP. The obtained results significantly extend the temperature range, where the refractive index of diamond was previously measured.

Fabrication and Characterization of FeNiCr Matrix-TiC Composite for Polishing CVD Diamond Film

Institute of Scientific and Technical Information of China (English)

Zhuji Jin; Zewei Yuan; Renke Kang; Boxian Dong

2009-01-01

Dynamic friction polishing (DFP) is one of the most promising methods appropriate for polishing CVD diamond film with high efficiency and low cost.By this method CVD diamond film is polished through being simply pressed against a metal disc rotating at a high speed utilizing the thermochemical reaction occurring as a result of dynamic friction between them in the atmosphere.However, the relatively soft materials such as stainless steel, cast iron and nickel alloy widely used for polishing CVD diamond film are easy to wear and adhere to diamond film surface, which may further lead to low efficiency and poor polishing quality.In this paper, FeNiCr matrix-TiC composite used as grinding wheel for polishing CVD diamond film was obtained by combination of mechanical alloying (MA) and spark plasma sintering (SPS).The process of ball milling,composition, density, hardness, high-temperature oxidation resistance and wear resistance of the sintered piece were analyzed.The results show that TiC was introduced in MA-SPS process and had good combination with FeNiCr matrix and even distribution in the matrix.The density of composite can be improved by mechanical alloying.The FeNiCr matrix-TiC composite obtained at 1273 K was found to be superior to at 1173 K sintering in hardness, high-temperature oxidation resistance and wearability.These properties are more favorable than SUS304 for the preparation of high-performance grinding wheel for polishing CVD diamond film.

Direct deposition of patterned nanocrystalline CVD diamond using an electrostatic self-assembly method with nanodiamond particles

Energy Technology Data Exchange (ETDEWEB)

Lee, Seung-Koo; Kim, Jong-Hoon; Jeong, Min-Goon; Lim, Dae-Soon [Department of Materials Science and Engineering, Korea University, Anam-Dong 5-1, Seoungbuk-Ku, Seoul 136-713 (Korea, Republic of); Song, Min-Jung, E-mail: dslim@korea.ac.kr [Center for Advanced Device Materials, Korea University, Anam-Dong 5-1, Seoungbuk-Ku, Seoul 136-713 (Korea, Republic of)

2010-12-17

Micron-sized and precise patterns of nanocrystalline CVD diamond were fabricated successfully on substrates using dispersed nanodiamond particles, charge connection by electrostatic self-assembly, and photolithography processes. Nanodiamond particles which had been dispersed using an attritional milling system were attached electrostatically on substrates as nuclei for diamond growth. In this milling process, poly sodium 4-styrene sulfonate (PSS) was added as an anionic dispersion agent to produce the PSS/nanodiamond conjugates. Ultra dispersed nanodiamond particles with a {zeta}-potential and average particle size of - 60.5 mV and {approx} 15 nm, respectively, were obtained after this milling process. These PSS/nanodiamond conjugates were attached electrostatically to a cationic polyethyleneimine (PEI) coated surface on to which a photoresist had been patterned in an aqueous solution of the PSS/nanodiamond conjugated suspension. A selectively seeded area was formed successfully using the above process. A hot filament chemical vapor deposition system was used to synthesize the nanocrystalline CVD diamond on the seeded area. Micron-sized, thin and precise nanocrystalline CVD diamond patterns with a high nucleation density (3.8 {+-} 0.4 x 10{sup 11} cm{sup -2}) and smooth surface were consequently fabricated.

Direct deposition of patterned nanocrystalline CVD diamond using an electrostatic self-assembly method with nanodiamond particles

International Nuclear Information System (INIS)

Lee, Seung-Koo; Kim, Jong-Hoon; Jeong, Min-Goon; Lim, Dae-Soon; Song, Min-Jung

2010-01-01

Micron-sized and precise patterns of nanocrystalline CVD diamond were fabricated successfully on substrates using dispersed nanodiamond particles, charge connection by electrostatic self-assembly, and photolithography processes. Nanodiamond particles which had been dispersed using an attritional milling system were attached electrostatically on substrates as nuclei for diamond growth. In this milling process, poly sodium 4-styrene sulfonate (PSS) was added as an anionic dispersion agent to produce the PSS/nanodiamond conjugates. Ultra dispersed nanodiamond particles with a ζ-potential and average particle size of - 60.5 mV and ∼ 15 nm, respectively, were obtained after this milling process. These PSS/nanodiamond conjugates were attached electrostatically to a cationic polyethyleneimine (PEI) coated surface on to which a photoresist had been patterned in an aqueous solution of the PSS/nanodiamond conjugated suspension. A selectively seeded area was formed successfully using the above process. A hot filament chemical vapor deposition system was used to synthesize the nanocrystalline CVD diamond on the seeded area. Micron-sized, thin and precise nanocrystalline CVD diamond patterns with a high nucleation density (3.8 ± 0.4 x 10 11 cm -2 ) and smooth surface were consequently fabricated.

The uniquely high-temperature character of Cullinan diamonds: A signature of the Bushveld mantle plume?

Science.gov (United States)

Korolev, N. M.; Kopylova, M.; Bussweiler, Y.; Pearson, D. G.; Gurney, J.; Davidson, J.

2018-04-01

The mantle beneath the Cullinan kimberlite (formerly known as "Premier") is a unique occurrence of diamondiferous cratonic mantle where diamonds were generated contemporaneously and shortly following a mantle upwelling that led to the formation of a Large Igneous Province that produced the world's largest igneous intrusion - the 2056 Ma Bushveld Igneous Complex (BIC). We studied 332 diamond inclusions from 202 Cullinan diamonds to investigate mantle thermal effects imposed by the formation of the BIC. The overwhelming majority of diamonds come from three parageneses: (1) lithospheric eclogitic (69%), (2) lithospheric peridotitic (21%), and (3) sublithospheric mafic (9%). The lithospheric eclogitic paragenesis is represented by clinopyroxene, garnet, coesite and kyanite. Main minerals of the lithospheric peridotitic paragenesis are forsterite, enstatite, Cr-pyrope, Cr-augite and spinel; the sublithospheric mafic association includes majorite, CaSiO3 phases and omphacite. Diamond formation conditions were calculated using an Al-in-olivine thermometer, a garnet-clinopyroxene thermometer, as well as majorite and Raman barometers. The Cullinan diamonds may be unique on the global stage in recording a cold geotherm of 40 mW/m2 in cratonic lithosphere that was in contact with underlying convecting mantle at temperatures of 1450-1550 °C. The studied Cullinan diamonds contain a high proportion of inclusions equilibrated at temperatures exceeding the ambient 1327 °C adiabat, i.e. 54% of eclogitic diamonds and 41% of peridotitic diamonds. By contrast, ≤ 1% of peridotitic diamond inclusions globally yield equally high temperatures. We propose that the Cullinan diamond inclusions recorded transient, slow-dissipating thermal perturbations associated with the plume-related formation of the 2 Ga Bushveld igneous province. The presence of inclusions in diamond from the mantle transition zone at 300-650 km supports this view. Cullinan xenoliths indicative of the thermal state of

Structural Transformation upon Nitrogen Doping of Ultrananocrystalline Diamond Films by Microwave Plasma CVD

Directory of Open Access Journals (Sweden)

Chien-Chung Teng

2009-01-01

Full Text Available The molecular properties and surface morphology of undoped and N-doped ultra-nanocrystalline diamond (UNCD films deposited by microwave plasma CVD with addition of nitrogen are investigated with various spectroscopic techniques. The results of spatially resolved Raman scattering, ATR/FT-IR and XPS spectra show more amorphous and sp2/sp3 ratio characteristics in N-doped UNCD films. The surface morphology in AFM scans shows larger nanocrystalline diamond clusters in N-doped UNCD films. Incorporation of nitrogen into UNCD films has promoted an increase of amorphous sp2-bonded carbons in the grain boundaries and the size of nanocrystalline diamond grains that are well correlated to the reported enhancement of conductivity and structural changes of UNCD films.

Preliminary results from a novel CVD diamond detector system for molecular imaging applications

International Nuclear Information System (INIS)

Mahon, A.R.

1996-01-01

A novel biomolecular imaging system incorporating a Chemical Vapour Deposition diamond detector is in development. The synthetic diamond is used as a UV detector to image nucleic acids in electrophoresis gels. The microstrip diamond detector currently has a spatial resolution of 30 μm. Preliminary results are presented which include: QE measurements of diamond detectors, detector time response, detector UV response and current detection limits of biomolecules in gel. The potential applications of the technology, and its significant advantages in speed and sensitivity over the current systems are discussed

A high-speed Schottky detector for ultra-wideband communications

DEFF Research Database (Denmark)

Valdecasa, Guillermo Silva; Cimoli, Bruno; Blanco Granja, Ángel

2017-01-01

This letter reviews the design procedure of a high‐speed Schottky video detector for high‐data‐rate communications within the ultra‐wideband (UWB) frequencies. The classic design approach for video detectors is extended with a mixer‐like analysis, which results in a more detailed assessment of th....... Using 0 dBm carrier power, the lowest measured conversion loss is 10 dB for a video frequency of 1.1 GHz and better than 13 dB up to 1.8 GHz....

The effect of cognitive remediation in individuals at ultra-high risk for psychosis

DEFF Research Database (Denmark)

Glenthøj, Louise Birkedal; Hjorthøj, Carsten; Kristensen, Tina Dam

2017-01-01

of five studies that reported a cognitive outcome found cognitive remediation to improve cognition in the domains of verbal memory, attention, and processing speed. Two out of four studies that reported on functional outcome found cognitive remediation to improve the functional outcome in the domains...... of social functioning and social adjustment. Zero out of the five studies that reported such an outcome found cognitive remediation to affect the magnitude of clinical symptoms. Research on the effect of cognitive remediation in the ultra-high risk state is still scarce. The current state of evidence...

Plasma spraying method for forming diamond and diamond-like coatings

Science.gov (United States)

Holcombe, Cressie E.; Seals, Roland D.; Price, R. Eugene

1997-01-01

A method and composition for the deposition of a thick layer (10) of diamond or diamond-like material. The method includes high temperature processing wherein a selected composition (12) including at least glassy carbon is heated in a direct current plasma arc device to a selected temperature above the softening point, in an inert atmosphere, and is propelled to quickly quenched on a selected substrate (20). The softened or molten composition (18) crystallizes on the substrate (20) to form a thick deposition layer (10) comprising at least a diamond or diamond-like material. The selected composition (12) includes at least glassy carbon as a primary constituent (14) and may include at least one secondary constituent (16). Preferably, the secondary constituents (16) are selected from the group consisting of at least diamond powder, boron carbide (B.sub.4 C) powder and mixtures thereof.

An investigation of laser cutting quality of 22MnB5 ultra high strength steel using response surface methodology

Science.gov (United States)

Tahir, Abdul Fattah Mohd; Aqida, Syarifah Nur

2017-07-01

In hot press forming, changes of mechanical properties in boron steel blanks have been a setback in trimming the final shape components. This paper presents investigation of kerf width and heat affected zone (HAZ) of ultra high strength 22MnB5 steel cutting. Sample cutting was conducted using a 4 kW Carbon Dioxide (CO2) laser machine with 10.6 μm wavelength with the laser spot size of 0.2 mm. A response surface methodology (RSM) using three level Box-Behnken design of experiment was developed with three factors of peak power, cutting speed and duty cycle. The parameters were optimised for minimum kerf width and HAZ formation. Optical evaluation using MITUTOYO TM 505 were conducted to measure the kerf width and HAZ region. From the findings, laser duty cycle was crucial to determine cutting quality of ultra-high strength steel; followed by cutting speed and laser power. Meanwhile, low power intensity with continuous wave contributes the narrowest kerf width formation and least HAZ region.

Workshop on diamond and diamond-like-carbon films for the transportation industry

Energy Technology Data Exchange (ETDEWEB)

Nichols, F.A.; Moores, D.K. [eds.

1993-01-01

Applications exist in advanced transportation systems as well as in manufacturing processes that would benefit from superior tribological properties of diamond, diamond-like-carbon and cubic boron nitride coatings. Their superior hardness make them ideal candidates as protective coatings to reduce adhesive, abrasive and erosive wear in advanced diesel engines, gas turbines and spark-ignited engines and in machining and manufacturing tools as well. The high thermal conductivity of diamond also makes it desirable for thermal management not only in tribological applications but also in high-power electronic devices and possibly large braking systems. A workshop has been recently held at Argonne National Laboratory entitled ``Diamond and Diamond-Like-Carbon Films for Transportation Applications`` which was attended by 85 scientists and engineers including top people involved in the basic technology of these films and also representatives from many US industrial companies. A working group on applications endorsed 18 different applications for these films in the transportation area alone. Separate abstracts have been prepared.

Ultra-wideband wireless receiver front-end for high-speed indoor applications

Directory of Open Access Journals (Sweden)

Zhe-Yang Huang

2014-12-01

Full Text Available Low-noise, ultra-wideband (UWB wireless receiver front-end circuits were presented in this study. A two-stage common-source low-noise amplifier with wideband input impedance matching network, an active-balun and a double-balanced down-conversion mixer were adopted in the UWB wireless receiver front-end. The proposed wireless receiver front-end circuits were implemented in 0.18 μm radio-frequency-CMOS process. The maximum down-conversion power gain of the front-end is 25.8 dB; minimum single-sideband noise figure of the front-end is 4.9 dB over complete UWB band ranging from 3.1 to 10.6 GHz. Power consumption including buffers is 39.2 mW.

Diamond film growth with modification properties of adhesion between substrate and diamond film

Directory of Open Access Journals (Sweden)

Setasuwon P.

2004-03-01

Full Text Available Diamond film growth was studied using chemical vapor deposition (CVD. A special equipment was build in-house, employing a welding torch, and substrate holder with a water-cooling system. Acetylene and oxygen were used as combustion gases and the substrate was tungsten carbide cobalt. It was found that surface treatments, such as diamond powder scratching or acid etching, increase the adhesion and prevent the film peel-off. Diamond powder scratching and combined diamond powder scratching with acid etching gave the similar diamond film structure with small grain and slightly rough surface. The diamond film obtained with both treatments has high adhesion and can withstand internal stress better than ones obtained by untreated surface or acid etching alone. It was also found that higher substrate temperature produced smoother surface and more uniform diamond grain.

Clinopyroxenes still trapped in diamonds: high-energy synchrotron X-ray diffraction as a chemical probe

Science.gov (United States)

Casati, Nicola; Nestola, Fabrizio; Alvaro, Matteo; Wilhelm, Heribert; Kleppe, Annette; Nimis, Paolo; Harris, Jeffrey W.

2014-05-01

Clinopyroxenes are mainly Ca-Na-Fe-Mg-silicates constituting a significant portion of the Earth's upper mantle up to 20% of such shell of our planet. They could be found as typical mineral inclusions in diamonds being diopsidic and omphacitic in composition and, together with garnets, cover a key role in providing indications concerning the source rock in which the diamond crystallize. In detail, it is well known that eclogitic diamonds are characterized by clinopyroxenes with omphacitic compositions (about Ca0.5Na0.5Mg0.5Al0.5Si2O6) whereas peridotitic diamonds show clinopyroxenes very rich in the diopside end-member (CaMgSi2O6). In order to get direct chemical composition on the inclusions, and therefore on the diamond origin source, it is obviously necessary to extract them breaking and/or polishing the diamond host. However, a non-destructive investigation of an inclusion still trapped in a diamond is useful and important for different reasons: (1) the inclusions could be under pressure and their crystal structure can be modified if the pressure is released by the extraction; (2) the residual pressure on the inclusion can provide information about the formation pressure of the diamond (e.g. Nestola et al. 2011 and references therein); (3) the morphology and growth relationships of the inclusion with the host diamond can provide indications about its protogenetic vs. syngenetic and/or epigenetic nature; and (4) preservation of the diamond surface growth features can maintain crucial information on late oxidation processes (Fedortchouk et al. 2011). However the available methods to measure the composition of the inclusions implies to destroy the sample. The aim of this work is to obtain chemical information on the inclusions still trapped in their diamond host and therefore to indicate the diamond origin without extracting the inclusions. The work was carried out by single crystal X-ray diffraction using a new experimental approach by high energy synchrotron

Development of CVD diamond radiation detectors

CERN Document Server

Adam, W; Berdermann, E; Bogani, F; Borchi, E; Bruzzi, Mara; Colledani, C; Conway, J; Dabrowski, W; Delpierre, P A; Deneuville, A; Dulinski, W; van Eijk, B; Fallou, A; Fisch, D; Foulon, F; Friedl, M; Gan, K K; Gheeraert, E; Grigoriev, E A; Hallewell, G D; Hall-Wilton, R; Han, S; Hartjes, F G; Hrubec, Josef; Husson, D; Kagan, H; Kania, D R; Kaplon, J; Kass, R; Knöpfle, K T; Krammer, Manfred; Manfredi, P F; Meier, D; Mishina, M; Le Normand, F; Pan, L S; Pernegger, H; Pernicka, Manfred; Pirollo, S; Re, V; Riester, J L; Roe, S; Roff, D G; Rudge, A; Schnetzer, S R; Sciortino, S; Speziali, V; Stelzer, H; Stone, R; Tapper, R J; Tesarek, R J; Thomson, G B; Trawick, M L; Trischuk, W; Turchetta, R; Walsh, A M; Wedenig, R; Weilhammer, Peter; Ziock, H J; Zoeller, M M

1998-01-01

Diamond is a nearly ideal material for detecting ionizing radiation. Its outstanding radiation hardness, fast charge collection and low leakage current allow a diamond detector to be used in high ra diation, high temperature and in aggressive chemical media. We have constructed charged particle detectors using high quality CVD diamond. Characterization of the diamond samples and various detect ors are presented in terms of collection distance, $d=\\mu E \\tau$, the average distance electron-hole pairs move apart under the influence of an electric field, where $\\mu$ is the sum of carrier mo bilities, $E$ is the applied electric field, and $\\tau$ is the mobility weighted carrier lifetime. Over the last two years the collection distance increased from $\\sim$ 75 $\\mu$m to over 200 $\\mu$ m. With this high quality CVD diamond a series of micro-strip and pixel particle detectors have been constructed. These devices were tested to determine their position resolution and signal to n oise performance. Diamond detectors w...

Optical engineering of diamond

CERN Document Server

Rabeau, James R

2013-01-01

This is the first comprehensive book on the engineering of diamond optical devices. It will give readers an up-to-date account of the properties of optical quality synthetic diamond (single crystal, nanodiamond and polycrystalline) and reviews the large and growing field of engineering of diamond-based optical devices, with applications in quantum computation, nano-imaging, high performance lasers, and biomedicine. It aims to provide scientists, engineers and physicists with a valuable resource and reference book for the design and performance of diamond-based optical devices.

Nanocrystalline diamond films for biomedical applications

DEFF Research Database (Denmark)

Pennisi, Cristian Pablo; Alcaide, Maria

2014-01-01

Nanocrystalline diamond films, which comprise the so called nanocrystalline diamond (NCD) and ultrananocrystalline diamond (UNCD), represent a class of biomaterials possessing outstanding mechanical, tribological, and electrical properties, which include high surface smoothness, high corrosion...... performance of nanocrystalline diamond films is reviewed from an application-specific perspective, covering topics such as enhancement of cellular adhesion, anti-fouling coatings, non-thrombogenic surfaces, micropatterning of cells and proteins, and immobilization of biomolecules for bioassays. In order...

Diamond Sensors for Energy Frontier Experiments

CERN Document Server

Schnetzer, Steve

2014-01-01

We discuss the use of diamond sensors in high-energy, high-i ntensity collider experiments. Re- sults from diamond sensor based beam conditions monitors in the ATLAS and CMS experiments at the CERN Large Hadron Collider (LHC) are presented and pla ns for diamond based luminosity monitors for the upcoming LHC run are described. We describe recent measurements on single crystal diamond sensors that indicate a polarization effec t that causes a reduction of charge col- lection efficiency as a function of particle flux. We conclude by describing new developments on the promising technology of 3D diamond sensors.

In vitro assessment of cutting efficiency and durability of zirconia removal diamond rotary instruments.

Science.gov (United States)

Kim, Joon-Soo; Bae, Ji-Hyeon; Yun, Mi-Jung; Huh, Jung-Bo

2017-06-01

Recently, zirconia removal diamond rotary instruments have become commercially available for efficient cutting of zirconia. However, research of cutting efficiency and the cutting characteristics of zirconia removal diamond rotary instruments is limited. The purpose of this in vitro study was to assess and compare the cutting efficiency, durability, and diamond rotary instrument wear pattern of zirconia diamond removal rotary instruments with those of conventional diamond rotary instruments. In addition, the surface characteristics of the cut zirconia were assessed. Block specimens of 3 mol% yttrium cation-doped tetragonal zirconia polycrystal were machined 10 times for 1 minute each using a high-speed handpiece with 6 types of diamond rotary instrument from 2 manufacturers at a constant force of 2 N (n=5). An electronic scale was used to measure the lost weight after each cut in order to evaluate the cutting efficiency. Field emission scanning electron microscopy was used to evaluate diamond rotary instrument wear patterns and machined zirconia block surface characteristics. Data were statistically analyzed using the Kruskal-Wallis test, followed by the Mann-Whitney U test (α=.05). Zirconia removal fine grit diamond rotary instruments showed cutting efficiency that was reduced compared with conventional fine grit diamond rotary instruments. Diamond grit fracture was the most dominant diamond rotary instrument wear pattern in all groups. All machined zirconia surfaces were primarily subjected to plastic deformation, which is evidence of ductile cutting. Zirconia blocks machined with zirconia removal fine grit diamond rotary instruments showed the least incidence of surface flaws. Although zirconia removal diamond rotary instruments did not show improved cutting efficiency compared with conventional diamond rotary instruments, the machined zirconia surface showed smoother furrows of plastic deformation and fewer surface flaws. Copyright © 2016 Editorial Council

35 Gb/s Ultra-wideband Technology for Advanced Communications

DEFF Research Database (Denmark)

Puerta Ramírez, Rafael; Vegas Olmos, Juan José; Tafur Monroy, Idelfonso

be applied, evolving from classic spectral inefficient pulsebased systems to more advanced and flexible modulation schemes. Ultra-wideband technology is suitable for low-power high-speed wireless communication systems over short distances, and is an appealing alternative for next generation networks ranging......The fast development of electronics and portable devices, intended mainly for multimedia applications, is increasing exponentially the data traffic demands per user. To cope with these new data demands in limited bandwidth systems, new technologies must be explored and new transmission schemes must...... from high-speed wireless personal area networks, to the internet of things applications. Its popularity stems from the fact that they can be used as an overlay to existing systems, without interference, operating in parallel to existing wireless systems, which perceive ultra-wideband emissions...

Noble gas studies in vapor-growth diamonds: Comparison with shock-produced diamonds and the origin of diamonds in ureilites

Energy Technology Data Exchange (ETDEWEB)

Matsuda, Junichi; Fukunaga, Kazuya; Ito, Keisuke (Kobe Univ. (Japan))

1991-07-01

The authors synthesized vapor-trowth diamonds by two kinds of Chemical Vapor Deposition (CVD) using microwave (MWCVD) and hot filament (HFCVD) ionization of gases, and examined elemental abundances and isotopic compositions of the noble gases trapped in the diamonds. It is remarkable that strong differences existed in the noble gas concentrations in the two kinds of CVD diamonds: large amounts of noble gases were trapped in the MWCVD diamonds, but not in the HFCVD diamonds. The heavy noble gases (Ar to Xe) in the MWCVD diamonds were highly fractionated compared with those in the ambient atmosphere, and are in good agreement with the calculated fractionation patterns for plasma at an electron temperature of 7,000-9,000 K. These results strongly suggest that the trapping mechanism of noble gases in CVD diamonds is ion implantation during diamond growth. The degrees of fractionation of heavy noble gases were also in good agreement with those in ureilites. The vapor-growth hypothesis is discussed in comparison with the impact-shock hypothesis as a better model for the origin of diamonds in ureilites. The diamond (and graphite, amorphous carbon, too) may have been deposited on early condensates such as Re, Ir, W, etc. This model explains the chemical features of vein material in ureilites; the refractory siderophile elements are enriched in carbon and noble gases and low in normal siderophiles. The vapor-growth model is also compatible with the oxygen isotopic data of ureilites which suggests that nebular processes are primarily responsible for the composition of ureilites.

Thermal, structural, and fabrication aspects of diamond windows for high power synchrotron x-ray beamlines

International Nuclear Information System (INIS)

Khounsary, A.M.; Phillips, W.

1992-01-01

Recent advances in chemical vapor deposition (CVD) technology have made it possible to produce thin free-standing diamond foils that can be used as the window material in high heat load, synchrotron beamlines. Numerical simulations suggest that these windows can offer an attractive and at times the only altemative to beryllium windows for use in third generation x-ray synchrotron radiation beamlines. Utilization, design, and fabrication aspects of diamond windows for high heat load x-ray beamlines are discussed, as are the microstructure characteristics bearing on diamond's performance in this role. Analytic and numerical results are also presented to provide a basis for the design and testing of such windows

High-speed fan-beam reconstruction using direct two-dimensional Fourier transform method

International Nuclear Information System (INIS)

Niki, Noboru; Mizutani, Toshio; Takahashi, Yoshizo; Inouye, Tamon.

1984-01-01

Since the first development of X-ray computer tomography (CT), various efforts have been made to obtain high quality of high-speed image. However, the development of high resolution CT and the ultra-high speed CT to be applied to hearts is still desired. The X-ray beam scanning method was already changed from the parallel beam system to the fan-beam system in order to greatly shorten the scanning time. Also, the filtered back projection (DFBP) method has been employed to directly processing fan-beam projection data as reconstruction method. Although the two-dimensional Fourier transform (TFT) method significantly faster than FBP method was proposed, it has not been sufficiently examined for fan-beam projection data. Thus, the ITFT method was investigated, which first executes rebinning algorithm to convert the fan-beam projection data to the parallel beam projection data, thereafter, uses two-dimensional Fourier transform. By this method, although high speed is expected, the reconstructed images might be degraded due to the adoption of rebinning algorithm. Therefore, the effect of the interpolation error of rebinning algorithm on the reconstructed images has been analyzed theoretically, and finally, the result of the employment of spline interpolation which allows the acquisition of high quality images with less errors has been shown by the numerical and visual evaluation based on simulation and actual data. Computation time was reduced to 1/15 for the image matrix of 512 and to 1/30 for doubled matrix. (Wakatsuki, Y.)

The global lambda visualization facility: An international ultra-high-definition wide-area visualization collaboratory

Science.gov (United States)

Leigh, J.; Renambot, L.; Johnson, Aaron H.; Jeong, B.; Jagodic, R.; Schwarz, N.; Svistula, D.; Singh, R.; Aguilera, J.; Wang, X.; Vishwanath, V.; Lopez, B.; Sandin, D.; Peterka, T.; Girado, J.; Kooima, R.; Ge, J.; Long, L.; Verlo, A.; DeFanti, T.A.; Brown, M.; Cox, D.; Patterson, R.; Dorn, P.; Wefel, P.; Levy, S.; Talandis, J.; Reitzer, J.; Prudhomme, T.; Coffin, T.; Davis, B.; Wielinga, P.; Stolk, B.; Bum, Koo G.; Kim, J.; Han, S.; Corrie, B.; Zimmerman, T.; Boulanger, P.; Garcia, M.

2006-01-01

The research outlined in this paper marks an initial global cooperative effort between visualization and collaboration researchers to build a persistent virtual visualization facility linked by ultra-high-speed optical networks. The goal is to enable the comprehensive and synergistic research and development of the necessary hardware, software and interaction techniques to realize the next generation of end-user tools for scientists to collaborate on the global Lambda Grid. This paper outlines some of the visualization research projects that were demonstrated at the iGrid 2005 workshop in San Diego, California.

A study on ultra-precision machining technique for Al6061-T6 to fabricate space infrared optics

Science.gov (United States)

Ryu, Geun-man; Lee, Gil-jae; Hyun, Sang-won; Sung, Ha-yeong; Chung, Euisik; Kim, Geon-hee

2014-08-01

In this paper, analysis of variance on designed experiments with full factorial design was applied to determine the optimized machining parameters for ultra-precision fabrication of the secondary aspheric mirror, which is one of the key elements of the space cryogenic infrared optics. A single point diamond turning machine (SPDTM, Nanotech 4μpL Moore) was adopted to fabricate the material, AL6061-T6, and the three machining parameters of cutting speed, feed rate and depth of cut were selected. With several randomly assigned experimental conditions, surface roughness of each condition was measured by a non-contact optical profiler (NT2000; Vecco). As a result of analysis using Minitab, the optimum cutting condition was determined as following; cutting speed: 122 m/min, feed rate: 3 mm/min and depth of cut: 1 μm. Finally, a 120 mm diameter aspheric secondary mirror was attached to a particularly designed jig by using mixture of paraffin and wax and successfully fabricated under the optimum machining parameters. The profile of machined surface was measured by a high-accuracy 3-D profilometer(UA3P; Panasonic) and we obtained the geometrical errors of 30.6 nm(RMS) and 262.4 nm(PV), which satisfy the requirements of the space cryogenic infrared optics.

Ultra-high resolution protein crystallography

International Nuclear Information System (INIS)

Takeda, Kazuki; Hirano, Yu; Miki, Kunio

2010-01-01

Many protein structures have been determined by X-ray crystallography and deposited with the Protein Data Bank. However, these structures at usual resolution (1.5< d<3.0 A) are insufficient in their precision and quantity for elucidating the molecular mechanism of protein functions directly from structural information. Several studies at ultra-high resolution (d<0.8 A) have been performed with synchrotron radiation in the last decade. The highest resolution of the protein crystals was achieved at 0.54 A resolution for a small protein, crambin. In such high resolution crystals, almost all of hydrogen atoms of proteins and some hydrogen atoms of bound water molecules are experimentally observed. In addition, outer-shell electrons of proteins can be analyzed by the multipole refinement procedure. However, the influence of X-rays should be precisely estimated in order to derive meaningful information from the crystallographic results. In this review, we summarize refinement procedures, current status and perspectives for ultra high resolution protein crystallography. (author)

The optimization of the cutting process of diamonds with a YAG laser

Directory of Open Access Journals (Sweden)

A. J. Lubbe

1993-07-01

Full Text Available A laser cannot, as generally assumed by the layman, cut right through a diamond with a single cut. A couple of hundred cuts may be necessary to "chip carve" through a diamond. There are several parameters, for example cutting speed, focus point, overlapping of cuts, etc., that influence the cutting process. With a view to optimizing the cutting process, laser cuts in diamonds were studied in a systematic way with the aid of an electron microscope. The method, technique and the results of the research are discussed in this article.

Cutting force and wear evaluation in peripheral milling by CVD diamond dental tools

International Nuclear Information System (INIS)

Polini, R.; Allegri, A.; Guarino, S.; Quadrini, F.; Sein, H.; Ahmed, W.

2004-01-01

Co-cemented tungsten carbide (WC-Co) tools are currently employed in dental application for prosthesis fabrication. The deposition of a diamond coating onto WC-Co tools could allow both to increase the tool life and tool performance at higher speeds. However, at present it is very difficult to quantify the effective advantage of the application of a diamond coating onto dental tools compared to traditional uncoated tools. Therefore, in this work, we have deposited diamond coatings onto WC-Co dental tools having different geometries by Hot Filament Chemical Vapour Deposition (HFCVD). Prior to deposition, the WC-Co tools were pre-treated in order to roughen the surface and to modify the chemical surface composition. The use of the HFCVD process enabled the deposition of a uniform coating despite the complex geometries of the dental mills. For the first time, in accordance to the knowledge of the authors, we have studied and compared the cutting behaviour of both virgin and diamond-coated dental tools by measuring both wear and cutting force time evolution under milling a very hard Co-Cr-Mo dental alloy. To ensure constant cutting rate (20,000-r.p.m. cutting rate, 0.01-m/min feed rate and 0.5-mm depth of cut), a proper experimental apparatus was used. Three different mill geometries were considered in both coated and uncoated conditions. The results showed that, under the high-speed conditions employed, uncoated tools underwent to catastrophic failure within a few seconds of machining. Diamond-coated tools exhibited much longer tool lives. Lower forces were measured when the coated tool was employed due to the much lower material-mill friction. The best behaviour was observed for coated mills with the presence of a chip-breaker

Growth of carbon fibres, sheets and tubes on diamond films under high power plasma etching conditions

Energy Technology Data Exchange (ETDEWEB)

Villalpando, I. [Centro de Investigacion de los Recursos Naturales, Antigua Normal Rural, Salaices, Lopez, Chihuahua (Mexico); John, P.; Wilson, J. I. B., E-mail: isaelav@hotmail.com [School of Engineering and Physical Sciences, Heriot-Watt University, Riccarton, Edinburgh, EH14-4AS (United Kingdom)

2017-11-01

The application of diamond as a plasma facing material for fusion reactors can be limited by unknown reactions between diamond and the chamber materials transported by the plasma. Transformation of diamond to other structures can cause problems such as contamination of the plasma with loose particles or retention of gases. We have seen that diamond thin films are eroded under hydrogen plasma etching, but if silicon is present the growth of various carbon structures on diamond films is observed. We have produced carbon with different morphologies on diamond films including fibres, sheets with flower-like shapes and tubes and proposed growth mechanisms based on the results of scanning electron microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy. Sample surfaces contain silicon and are oxidised having COO and CO groups as seen by XP S analysis. Raman analyses revealed a spectrum typical for graphite combined with that from diamond that remains on the surface after hydrogen bombardment. The results of this sturdy show the experimental conditions in which carbon fibres, sheets and tubes are produced under high-power hydrogen etching of diamond films and open the possibility to other applications such as catalysts, sensors and the production of electrodes. (Author)

Growth of carbon fibres, sheets and tubes on diamond films under high power plasma etching conditions

International Nuclear Information System (INIS)

Villalpando, I.; John, P.; Wilson, J. I. B.

2017-01-01

The application of diamond as a plasma facing material for fusion reactors can be limited by unknown reactions between diamond and the chamber materials transported by the plasma. Transformation of diamond to other structures can cause problems such as contamination of the plasma with loose particles or retention of gases. We have seen that diamond thin films are eroded under hydrogen plasma etching, but if silicon is present the growth of various carbon structures on diamond films is observed. We have produced carbon with different morphologies on diamond films including fibres, sheets with flower-like shapes and tubes and proposed growth mechanisms based on the results of scanning electron microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy. Sample surfaces contain silicon and are oxidised having COO and CO groups as seen by XP S analysis. Raman analyses revealed a spectrum typical for graphite combined with that from diamond that remains on the surface after hydrogen bombardment. The results of this sturdy show the experimental conditions in which carbon fibres, sheets and tubes are produced under high-power hydrogen etching of diamond films and open the possibility to other applications such as catalysts, sensors and the production of electrodes. (Author)

Investigation of the physics of diamond MEMS : diamond allotrope lithography

International Nuclear Information System (INIS)

Zalizniak, I.; Olivero, P.; Jamieson, D.N.; Prawer, S.; Reichart, P.; Rubanov, S.; Petriconi, S.

2005-01-01

We propose a novel lithography process in which ion induced phase transfomations of diamond form sacrificial layers allowing the fabrication of small structures including micro-electromechanical systems (MEMS). We have applied this novel lithography to the fabrication of diamond microcavities, cantilevers and optical waveguides. In this paper we present preliminary experiments directed at the fabrication of suspended diamond disks that have the potential for operation as optical resonators. Such structures would be very durable and resistant to chemical attack with potential applications as novel sensors for extreme environments or high temperature radiation detectors. (author). 3 refs., 3 figs

Diamond nanophotonics

Directory of Open Access Journals (Sweden)

Katja Beha

2012-12-01

Full Text Available We demonstrate the coupling of single color centers in diamond to plasmonic and dielectric photonic structures to realize novel nanophotonic devices. Nanometer spatial control in the creation of single color centers in diamond is achieved by implantation of nitrogen atoms through high-aspect-ratio channels in a mica mask. Enhanced broadband single-photon emission is demonstrated by coupling nitrogen–vacancy centers to plasmonic resonators, such as metallic nanoantennas. Improved photon-collection efficiency and directed emission is demonstrated by solid immersion lenses and micropillar cavities. Thereafter, the coupling of diamond nanocrystals to the guided modes of micropillar resonators is discussed along with experimental results. Finally, we present a gas-phase-doping approach to incorporate color centers based on nickel and tungsten, in situ into diamond using microwave-plasma-enhanced chemical vapor deposition. The fabrication of silicon–vacancy centers in nanodiamonds by microwave-plasma-enhanced chemical vapor deposition is discussed in addition.

Low velocity impact behaviour of ultra high strength concrete panels

Indian Academy of Sciences (India)

Ultra high strength concrete; panel; drop weight test; impact analysis;. ABAQUS. 1. Introduction. Ultra high strength concrete ... Knight (2012) investigated the dynamic behaviour of steel fibre reinforced concrete plates under impact loading with ...

Effect of Stand-Off Distance on Impact Pressure of High Speed Water Jets

Science.gov (United States)

Sittiwong, Wuttichai; Seehanam, Wirapan; Pianthong, Kulachate; Matthujak, Anirut

2010-06-01

High speed liquid jets may be applied to jet cutting, drilling and cleaning. Recently, in the automotive industries, the spray injection pressure becomes higher and higher to enhance the fuel mixing for the improved combustion efficiency. However, the ultra high injection pressure may cause the damage to the nozzle and also the combustion chamber. In the medical application, the high speed liquid injection might be applied for the drug delivery through the skin where the needle is not required anymore. From the above mentioned application, the investigation on the impact pressure of the high speed liquid jet relative to the stand-off distant is significant. The high speed liquid jets are generated by the projectile impact driven method. The high speed projectile is launched by the horizontal single stage powder gun. The experimental study focuses on the stand-off between 1.5 cm to 6.0 cm, while the nozzle contains approximately 1.5cm3 of water in its cavity. The nozzle conical angles are 30° and 60° with the orifice diameter of 0.7 mm. The jet velocities are measured by laser beam interruptions method. The target material is the Polymethyl Methacrylate (PMMA) which the impact pressure is measured by using a piezoelectric Polyvinylidene Fluoride (PVDF) film. From the experiments, the maximum water jet velocity of 2290 m/s can be obtained from the 30° conical angle nozzle. The maximum impact pressures of nozzle conical angle of 30° and 60° are 3.4 GPa and 2.6 GPa respectively, at stand-off distance 3 cm. However, at the stand-off distance more than 3 cm, the impact pressure significantly decreases, because of aerodynamic drag, jets core break-up, and atomization of the water.

Status and applications of diamond and diamond-like materials: An emerging technology

Science.gov (United States)

1990-01-01

Recent discoveries that make possible the growth of crystalline diamond by chemical vapor deposition offer the potential for a wide variety of new applications. This report takes a broad look at the state of the technology following from these discoveries in relation to other allied materials, such as high-pressure diamond and cubic boron nitride. Most of the potential defense, space, and commercial applications are related to diamond's hardness, but some utilize other aspects such as optical or electronic properties. The growth processes are reviewed, and techniques for characterizing the resulting materials' properties are discussed. Crystalline diamond is emphasized, but other diamond-like materials (silicon carbide, amorphous carbon containing hydrogen) are also examined. Scientific, technical, and economic problem areas that could impede the rapid exploitation of these materials are identified. Recommendations are presented covering broad areas of research and development.

Radiobiological response to ultra-short pulsed megavoltage electron beams of ultra-high pulse dose rate.

Science.gov (United States)

Beyreuther, Elke; Karsch, Leonhard; Laschinsky, Lydia; Leßmann, Elisabeth; Naumburger, Doreen; Oppelt, Melanie; Richter, Christian; Schürer, Michael; Woithe, Julia; Pawelke, Jörg

2015-08-01

In line with the long-term aim of establishing the laser-based particle acceleration for future medical application, the radiobiological consequences of the typical ultra-short pulses and ultra-high pulse dose rate can be investigated with electron delivery. The radiation source ELBE (Electron Linac for beams with high Brilliance and low Emittance) was used to mimic the quasi-continuous electron beam of a clinical linear accelerator (LINAC) for comparison with electron pulses at the ultra-high pulse dose rate of 10(10) Gy min(-1) either at the low frequency of a laser accelerator or at 13 MHz avoiding effects of prolonged dose delivery. The impact of pulse structure was analyzed by clonogenic survival assay and by the number of residual DNA double-strand breaks remaining 24 h after irradiation of two human squamous cell carcinoma lines of differing radiosensitivity. The radiation response of both cell lines was found to be independent from electron pulse structure for the two endpoints under investigation. The results reveal, that ultra-high pulse dose rates of 10(10) Gy min(-1) and the low repetition rate of laser accelerated electrons have no statistically significant influence (within the 95% confidence intervals) on the radiobiological effectiveness of megavoltage electrons.

Analysis about diamond tool wear in nano-metric cutting of single crystal silicon using molecular dynamics method

Science.gov (United States)

Wang, Zhiguo; Liang, Yingchun; Chen, Mingjun; Tong, Zhen; Chen, Jiaxuan

2010-10-01

Tool wear not only changes its geometry accuracy and integrity, but also decrease machining precision and surface integrity of workpiece that affect using performance and service life of workpiece in ultra-precision machining. Scholars made a lot of experimental researches and stimulant analyses, but there is a great difference on the wear mechanism, especially on the nano-scale wear mechanism. In this paper, the three-dimensional simulation model is built to simulate nano-metric cutting of a single crystal silicon with a non-rigid right-angle diamond tool with 0 rake angle and 0 clearance angle by the molecular dynamics (MD) simulation approach, which is used to investigate the diamond tool wear during the nano-metric cutting process. A Tersoff potential is employed for the interaction between carbon-carbon atoms, silicon-silicon atoms and carbon-silicon atoms. The tool gets the high alternating shear stress, the tool wear firstly presents at the cutting edge where intension is low. At the corner the tool is splitted along the {1 1 1} crystal plane, which forms the tipping. The wear at the flank face is the structure transformation of diamond that the diamond structure transforms into the sheet graphite structure. Owing to the tool wear the cutting force increases.

Low propagation loss in a one-port SAW resonator fabricated on single-crystal diamond for super-high-frequency applications.

Science.gov (United States)

Fujii, Satoshi; Odawara, Tatsuya; Yamada, Haruya; Omori, Tatsuya; Hashimoto, Ken-Ya; Torii, Hironori; Umezawa, Hitoshi; Shikata, Shinichi

2013-05-01

Diamond has the highest known SAW phase velocity, sufficient for applications in the gigahertz range. However, although numerous studies have demonstrated SAW devices on polycrystalline diamond thin films, all have had much larger propagation loss than single-crystal materials such as LiNbO3. Hence, in this study, we fabricated and characterized one-port SAW resonators on single-crystal diamond substrates synthesized using a high-pressure and high-temperature method to identify and minimize sources of propagation loss. A series of one-port resonators were fabricated with the interdigital transducer/ AlN/diamond structure and their characteristics were measured. The device with the best performance exhibited a resonance frequency f of 5.3 GHz, and the equivalent circuit model gave a quality factor Q of 5509. Thus, a large fQ product of approximately 2.9 × 10(13) was obtained, and the propagation loss was found to be only 0.006 dB/wavelength. These excellent properties are attributed mainly to the reduction of scattering loss in a substrate using a single-crystal diamond, which originated from the grain boundary of diamond and the surface roughness of the AlN thin film and the diamond substrate. These results show that single-crystal diamond SAW resonators have great potential for use in low-noise super-high-frequency oscillators.

Hydrogen doped thin film diamond. Properties and application for electronic devices

International Nuclear Information System (INIS)

Looi, H.J.

2000-01-01

The face centered cubic allotrope of carbon, diamond, is a semiconducting material which possesses a valuable combination of extreme properties such as super-hardness, highest thermal conductivity, chemical hardness, radiation hardness, wide bandgap and others. Advances in chemical vapour deposition (CVD) technology have lead to diamond becoming available in previously unattainable forms for example over large areas and with controllable purity. This has generated much research interest towards developing the knowledge and processing technology that would be necessary to fully exploit these extreme properties. Electronic devices fabricated on oxidised boron doped polycrystalline CVD diamond (PCD) displayed very poor and inconsistent characteristic. As a result, many electronic applications of polycrystalline diamond films were confined to ultra-violet (UV) and other forms of device which relied on the high intrinsic resistivity on undoped diamond films. If commercially accessible PCD films are to advance in areas which involve sophisticated electronic applications or to compete with existing semiconductors, the need for a more reliable and fully ionised dopant is paramount. This thesis describes a unique dopant discovered within the growth surface of PCD films. This dopant is related to hydrogen which arises during the growth of diamond films. The aim of this study is to characterise and identify possible applications for this form of dopant. The mechanism for carrier generation remains unknown and based on the experimental results in this work, a model is proposed. The Hall measurements conducted on this conductive layer revealed a p-type nature with promising properties for electronic device application. A more detail study based on electrical and surface science methods were carried out to identify the stability and operating conditions for this dopant. The properties of metal-semiconductor contacts on these surfaces were investigated. The fundamental knowledge

Amorphous Diamond MEMS and Sensors

Energy Technology Data Exchange (ETDEWEB)

SULLIVAN, JOHN P.; FRIEDMANN, THOMAS A.; ASHBY, CAROL I.; DE BOER, MAARTEN P.; SCHUBERT, W. KENT; SHUL, RANDY J.; HOHLFELDER, ROBERT J.; LAVAN, D.A.

2002-06-01

This report describes a new microsystems technology for the creation of microsensors and microelectromechanical systems (MEMS) using stress-free amorphous diamond (aD) films. Stress-free aD is a new material that has mechanical properties close to that of crystalline diamond, and the material is particularly promising for the development of high sensitivity microsensors and rugged and reliable MEMS. Some of the unique properties of aD include the ability to easily tailor film stress from compressive to slightly tensile, hardness and stiffness 80-90% that of crystalline diamond, very high wear resistance, a hydrophobic surface, extreme chemical inertness, chemical compatibility with silicon, controllable electrical conductivity from insulating to conducting, and biocompatibility. A variety of MEMS structures were fabricated from this material and evaluated. These structures included electrostatically-actuated comb drives, micro-tensile test structures, singly- and doubly-clamped beams, and friction and wear test structures. It was found that surface micromachined MEMS could be fabricated in this material easily and that the hydrophobic surface of the film enabled the release of structures without the need for special drying procedures or the use of applied hydrophobic coatings. Measurements using these structures revealed that aD has a Young's modulus of {approx}650 GPa, a tensile fracture strength of 8 GPa, and a fracture toughness of 8 MPa{center_dot}m {sup 1/2}. These results suggest that this material may be suitable in applications where stiction or wear is an issue. Flexural plate wave (FPW) microsensors were also fabricated from aD. These devices use membranes of aD as thin as {approx}100 nm. The performance of the aD FPW sensors was evaluated for the detection of volatile organic compounds using ethyl cellulose as the sensor coating. For comparable membrane thicknesses, the aD sensors showed better performance than silicon nitride based sensors. Greater

Architecting boron nanostructure on the diamond particle surface

International Nuclear Information System (INIS)

Bai, H.; Dai, D.; Yu, J.H.; Nishimura, K.; Sasaoka, S.; Jiang, N.

2014-01-01

The present study provides an efficient approach for nano-functionalization of diamond powders. Boron nanostructure can be grown on diamond particle entire surface by a simple heat-treatment process. After treatment, various boron nanoforms were grown on the diamond particle surface at different processing temperature. High-density boron nanowires (BNWs) grow on the diamond particle entire surface at 1333 K, while nanopillars cover diamond powders when the heat treatment process is performed at 1393 K. The influence of the pretreatment temperature on the microstructure and thermal conductivity of Cu/diamond composites were investigated. Cu/diamond composites with high thermal conductivity of 670 W (m K) −1 was obtained, which was achieved by the formation of large number of nanowires and nanopillars on the diamond particle surface.

Growth of high quality AlN films on CVD diamond by RF reactive magnetron sputtering

Science.gov (United States)

Chen, Liang-xian; Liu, Hao; Liu, Sheng; Li, Cheng-ming; Wang, Yi-chao; An, Kang; Hua, Chen-yi; Liu, Jin-long; Wei, Jun-jun; Hei, Li-fu; Lv, Fan-xiu

2018-02-01

A highly oriented AlN layer has been successfully grown along the c-axis on a polycrystalline chemical vapor deposited (CVD) diamond by RF reactive magnetron sputtering. Structural, morphological and mechanical properties of the heterostructure were investigated by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Transmission Electron Microscopy (TEM), X-ray diffraction (XRD), Nano-indentation and Four-probe meter. A compact AlN film was demonstrated on the diamond layer, showing columnar grains and a low surface roughness of 1.4 nm. TEM results revealed a sharp AlN/diamond interface, which was characterized by the presence of a distinct 10 nm thick buffer layer resulting from the initial AlN growth stage. The FWHM of AlN (002) diffraction peak and its rocking curve are as low as 0.41° and 3.35° respectively, indicating a highly preferred orientation along the c-axis. AlN sputtered films deposited on glass substrates show a higher bulk resistivity (up to 3 × 1012 Ω cm), compared to AlN films deposited on diamond (∼1010 Ω cm). Finally, the film hardness and Young's modulus of AlN films on diamond are 25.8 GPa and 489.5 GPa, respectively.

Deposition and micro electrical discharge machining of CVD-diamond layers incorporated with silicon

Science.gov (United States)

Kühn, R.; Berger, T.; Prieske, M.; Börner, R.; Hackert-Oschätzchen, M.; Zeidler, H.; Schubert, A.

2017-10-01

In metal forming, lubricants have to be used to prevent corrosion or to reduce friction and tool wear. From an economical and ecological point of view, the aim is to avoid the usage of lubricants. For dry deep drawing of aluminum sheets it is intended to apply locally micro-structured wear-resistant carbon based coatings onto steel tools. One type of these coatings are diamond layers prepared by chemical vapor deposition (CVD). Due to the high strength of diamond, milling processes are unsuitable for micro-structuring of these layers. In contrast to this, micro electrical discharge machining (micro EDM) is a suitable process for micro-structuring CVD-diamond layers. Due to its non-contact nature and its process principle of ablating material by melting and evaporating, it is independent of the hardness, brittleness or toughness of the workpiece material. In this study the deposition and micro electrical discharge machining of silicon incorporated CVD-diamond (Si-CVD-diamond) layers were presented. For this, 10 µm thick layers were deposited on molybdenum plates by a laser-induced plasma CVD process (LaPlas-CVD). For the characterization of the coatings RAMAN- and EDX-analyses were conducted. Experiments in EDM were carried out with a tungsten carbide tool electrode with a diameter of 90 µm to investigate the micro-structuring of Si-CVD-diamond. The impact of voltage, discharge energy and tool polarity on process speed and resulting erosion geometry were analyzed. The results show that micro EDM is a suitable technology for micro-structuring of silicon incorporated CVD-diamond layers.

PREFACE: Science's gem: diamond science 2009 Science's gem: diamond science 2009

Science.gov (United States)

Mainwood, Alison; Newton, Mark E.; Stoneham, Marshall

2009-09-01

Natural diamond has been valued for its appearance and mechanical properties for at least two thousand years. As a gem stone diamond is unsurpassed. However, scientific work, especially in the last 20 years, has demonstrated that diamond has numerous surprising properties and many unique ones. Some of the extreme properties have been known for many years, but the true scale of diamond's other highly desirable features is still only coming to light as control in the synthesis of diamond, and hence material perfection, improves. The ultimate prize for man-made diamond is surely not in the synthesis of gem stones, but in delivering technological solutions enabled by diamond to the challenges facing our society today. If the special properties are to be exploited to their full potential, at least four crucial factors must be considered. First, there must be sufficient scientific understanding of diamond to make applications effective, efficient and economical. Secondly, the means of fabrication and control of properties have to be achieved so that diamond's role can be optimised. Thirdly, it is not enough that its properties are superior to existing materials: they must be so much better that it is worth initiating new technologies to exploit them. Finally, any substantial applications will have to address the society's major needs worldwide. The clear technology drivers for the 21st century come from the biomedical technologies, the demand for energy subject to global constraints, and the information technologies, where perhaps diamond will provide the major enabling technology [1]. The papers in this volume concern the solid state physics of diamond, and primarily concern the first two factors: understanding, and control of properties. They address many of the outstanding basic problems, such as the identification of existing defects, which affect the material's properties, both desirable and less so. Regarding future substantial applications, one paper discusses

SiC interlayer by laser-cladding on WC-Co substrates for CVD diamond deposition

Energy Technology Data Exchange (ETDEWEB)

Contin, Andre; Fraga, Mariana Amorim; Vieira, Jose; Trava-Airoldi, Vladimir Jesus; Corat, Evaldo Jose, E-mail: andrecontin@yahoo.com.br [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil); Campos, Raonei Alves [Universidade Federal do Sul e Sudeste do Para (UNIFESSPA), Belem, PA (Brazil); Vasconcelos, Getulio [Instituto de Estudos Avancados (IEA), Sao Jose dos Campos, SP (Brazil)

2016-07-01

Full text: Despite their huge industrial potential and commercial interest, the direct diamond coating on cemented carbide (WC-Co) is limited, mainly because of the catalytic effect of Cobalt (Co) and the high difference in thermal expansion coefficient [1]. This results in poor adherence between diamond and WC-Co. In addition, the low diamond film adhesion to the cemented carbide useless for machining applications. Removal of Co binder from the substrate surface by superficial etching is one of the techniques used to improve the adhesion between diamond and WC-Co. For the present study, diamond films were deposited on WC-Co substrates with an intermediate barrier to block the Co diffusion to the surface substrate. The laser cladding process produced the SiC barrier, in which a powder layer is melted by a laser irradiation to create the coating on the substrate. The use of laser cladding is the novel method for an intermediate barrier for cemented carbides. The advantages of laser cladding include a faster processing speed, precision, versatility. We reported the application of pretreatment method called ESND (Electrostatic self-assembly seeding of nanocrystalline diamond). The nucleation density was around 10{sup 11}part/cm{sup 2}. Diamond films were grown by Hot Filament Chemical Vapor Deposition. Characterization of samples included Field Emission Gun-Scanning Electron Microscopy (FEG-SEM), Energy Dispersive X-ray (EDX), X-ray diffraction (XRD) and Raman Scattering Spectroscopy. Results showed that laser irradiation formed stable Co compounds in the interfacial barrier. It is because nucleation and good quality of diamond film since the cobalt are no longer free to migrate to the surface during the CVD diamond deposition. Reference: [1] Y. X. Cui, B. Shen, F. H. Sun. Diamond deposition on WC–Co substrate with amorphous SiC interlayer, Surface Engineering, 30, (2014) 237-243. (author)

High speed ultra-broadband amplitude modulators with ultrahigh extinction >65 dB.

Science.gov (United States)

Liu, S; Cai, H; DeRose, C T; Davids, P; Pomerene, A; Starbuck, A L; Trotter, D C; Camacho, R; Urayama, J; Lentine, A

2017-05-15

We experimentally demonstrate ultrahigh extinction ratio (>65 dB) amplitude modulators (AMs) that can be electrically tuned to operate across a broad spectral range of 160 nm from 1480 - 1640 nm and 95 nm from 1280 - 1375 nm. Our on-chip AMs employ one extra coupler compared with conventional Mach-Zehnder interferometers (MZI), thus form a cascaded MZI (CMZI) structure. Either directional or adiabatic couplers are used to compose the CMZI AMs and experimental comparisons are made between these two different structures. We investigate the performance of CMZI AMs under extreme conditions such as using 95:5 split ratio couplers and unbalanced waveguide losses. Electro-optic phase shifters are also integrated in the CMZI AMs for high-speed operation. Finally, we investigate the output optical phase when the amplitude is modulated, which provides us valuable information when both amplitude and phase are to be controlled. Our demonstration not only paves the road to applications such as quantum information processing that requires high extinction ratio AMs but also significantly alleviates the tight fabrication tolerance needed for large-scale integrated photonics.

Liquid jet impingement cooling with diamond substrates for extremely high heat flux applications

International Nuclear Information System (INIS)

Lienhard V, J.H.

1993-01-01

The combination of impinging jets and diamond substrates may provide an effective solution to a class of extremely high heat flux problems in which very localized heat loads must be removed. Some potential applications include the cooling of high-heat-load components in synchrotron x-ray, fusion, and semiconductor laser systems. Impinging liquid jets are a very effective vehicle for removing high heat fluxes. The liquid supply arrangement is relatively simple, and low thermal resistances can be routinely achieved. A jet's cooling ability is a strong function of the size of the cooled area relative to the jet diameter. For relatively large area targets, the critical heat fluxes can approach 20 W/mm 2 . In this situation, burnout usually originates at the outer edge of the cooled region as increasing heat flux inhibits the liquid supply. Limitations from liquid supply are minimized when heating is restricted to the jet stagnation zone. The high stagnation pressure and high velocity gradients appear to suppress critical flux phenomena, and fluxes of up to 400 W/mm 2 have been reached without evidence of burnout. Instead, the restrictions on heat flux are closely related to properties of the cooled target. Target properties become an issue owing to the large temperatures and large temperature gradients that accompany heat fluxes over 100 W/mm 2 . These conditions necessitate a target with both high thermal conductivity to prevent excessive temperatures and good mechanical properties to prevent mechanical failures. Recent developments in synthetic diamond technology present a possible solution to some of the solid-side constraints on heat flux. Polycrystalline diamond foils can now be produced by chemical vapor deposition in reasonable quantity and at reasonable cost. Synthetic single crystal diamonds as large as 1 cm 2 are also available

Characterization of a microDiamond detector in high-dose-per-pulse electron beams for intra operative radiation therapy.

Science.gov (United States)

Di Venanzio, C; Marinelli, Marco; Tonnetti, A; Verona-Rinati, G; Falco, M D; Pimpinella, M; Ciccotelli, A; De Stefano, S; Felici, G; Marangoni, F

2015-12-01

To characterize a synthetic diamond dosimeter (PTW Freiburg microDiamond 60019) in high dose-per-pulse electron beams produced by an Intra Operative Radiation Therapy (IORT) dedicated accelerator. The dosimetric properties of the microDiamond were assessed under 6, 8 and 9 MeV electron beams by a NOVAC11 mobile accelerator (Sordina IORT Technologies S.p.A.). The characterization was carried out with dose-per-pulse ranging from 26 to 105 mGy per pulse. The microDiamond performance was compared with an Advanced Markus ionization chamber and a PTW silicon diode E in terms of dose linearity, percentage depth dose (PDD) curves, beam profiles and output factors. A good linearity of the microDiamond response was verified in the dose range from 0.2 Gy to 28 Gy. A sensitivity of 1.29 nC/Gy was measured under IORT electron beams, resulting within 1% with respect to the one obtained in reference condition under (60)Co gamma irradiation. PDD measurements were found in agreement with the ones by the reference dosimeters, with differences in R50 values below 0.3 mm. Profile measurements evidenced a high spatial resolution of the microDiamond, slightly worse than the one of the silicon diode. The penumbra widths measured by the microDiamond resulted approximately 0.5 mm larger than the ones by the Silicon diode. Output factors measured by the microDiamond were found within 2% with those obtained by the Advanced Markus down to 3 cm diameter field sizes. The microDiamond dosimeter was demonstrated to be suitable for precise dosimetry in IORT applications under high dose-per-pulse conditions. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Ultra-high energy cosmic rays from white dwarf pulsars and the Hillas criterion

International Nuclear Information System (INIS)

Lobato, Ronaldo V.; Coelho, Jaziel G.; Malheiro, M.

2017-01-01

The origins of ultra-high-energy cosmic rays ( E ≳ 10 19 eV) are a mystery and still under debate in astroparticle physics. In recent years some efforts were made to understand their nature. In this contribution we consider the possibility of Some Soft Gamma Repeaters (SGRs) and Anomalous X-ray Pulsars (AXPs) beeing white dwarf pulsars, and show that these sources can achieve large electromagnetic potentials on their surface that accelerate particle almost at the speed of light, with energies E ∼ 10 20-21 eV. The sources SGRs/AXPs considered as highly magnetized white dwarfs are well described in the Hillas diagram, lying close to the AR Sorpii and AE Aquarii which are understood as white dwarf pulsars. (paper)

Ultrananocrystalline Diamond Membranes for Detection of High-Mass Proteins

Science.gov (United States)

Kim, H.; Park, J.; Aksamija, Z.; Arbulu, M.; Blick, R. H.

2016-12-01

Mechanical resonators realized on the nanoscale by now offer applications in mass sensing of biomolecules with extraordinary sensitivity. The general idea is that perfect mechanical mass sensors should be of extremely small size to achieve zepto- or yoctogram sensitivity in weighing single molecules similar to a classical scale. However, the small effective size and long response time for weighing biomolecules with a cantilever restricts their usefulness as a high-throughput method. Commercial mass spectrometry (MS), on the other hand, such as electrospray ionization and matrix-assisted laser desorption and ionization (MALDI) time of flight (TOF) and their charge-amplifying detectors are the gold standards to which nanomechanical resonators have to live up to. These two methods rely on the ionization and acceleration of biomolecules and the following ion detection after a mass selection step, such as TOF. The principle we describe here for ion detection is based on the conversion of kinetic energy of the biomolecules into thermal excitation of chemical vapor deposition diamond nanomembranes via phonons followed by phonon-mediated detection via field emission of thermally emitted electrons. We fabricate ultrathin diamond membranes with large lateral dimensions for MALDI TOF MS of high-mass proteins. These diamond membranes are realized by straightforward etching methods based on semiconductor processing. With a minimal thickness of 100 nm and cross sections of up to 400 ×400 μ m2 , the membranes offer extreme aspect ratios. Ion detection is demonstrated in MALDI TOF analysis over a broad range from insulin to albumin. The resulting data in detection show much enhanced resolution as compared to existing detectors, which can offer better sensitivity and overall performance in resolving protein masses.

Diamonds: powerful tools for high-pressure physics

International Nuclear Information System (INIS)

Anon.

1983-01-01

Diamond-anvil high-pressure studies have progressed to the point where they complement shock-wave studies. Because they operate at static high pressure, they permit time-consuming procedures, such as x-ray diffraction measurements for determining crystal structure. The sample material is completely recoverable and the method is adaptable to minute advantage when dealing with rare or hazardous materials. One of our goals in investigating the high-pressure behavior of iridium was to test the theoretical prediction that iridium would exhibit a phase transformation from the face-centered cubic crystal structure at about 9 GPa. Our finding that no such transformation takes place even at pressures up to 30 GPa will need to be taken into account by physicsts working to improve solid-state theory

Softening the ultra-stiff: Controlled variation of Young’s modulus in single-crystal diamond by ion implantation

International Nuclear Information System (INIS)

Battiato, A.; Lorusso, M.; Bernardi, E.; Picollo, F.; Bosia, F.; Ugues, D.; Zelferino, A.; Damin, A.; Baima, J.

2016-01-01

A combined experimental and numerical study on the variation of the elastic properties of defective single-crystal diamond is presented for the first time, by comparing nano-indentation measurements on MeV-ion-implanted samples with multi-scale modeling consisting of both ab initio atomistic calculations and meso-scale Finite Element Method (FEM) simulations. It is found that by locally introducing defects in the 2 × 10 18 –5 × 10 21  cm −3 density range, a significant reduction of Young’s modulus, as well as of density, can be induced in the diamond crystal structure without incurring in the graphitization of the material. Ab initio atomistic simulations confirm the experimental findings with a good degree of confidence. FEM simulations are further employed to verify the consistency of measured deformations with a stiffness reduction, and to derive strain and stress levels in the implanted region. Combining these experimental and numerical results, we also provide insight into the mechanism responsible for the depth dependence of the graphitization threshold in diamond. This work prospects the possibility of achieving accurate tunability of the mechanical properties of single-crystal diamond through defect engineering, with significant technological applications, e.g. the fabrication and control of the resonant frequency of diamond-based micromechanical resonators.

Mechanical pretreatment for improved adhesion of diamond coatings

International Nuclear Information System (INIS)

Toenshoff, H.K.; Mohlfeld, A.; Gey, C.; Winkler, J.

1999-01-01

Diamond coatings are mainly used in cutting processes due to their tribological characteristics. They show a high hardness, low friction coefficient, high wear resistance and good chemical inertness. In relation to polycrystalline diamond (PCD)-tipped cutting inserts, especially the advantageous chemical stability of diamond coatings is superior as no binder phases between diamond grains are used. However, the deposition of adherent high-quality diamond coatings has been found difficult. Thus, substrate pretreatment is utilised to improve film adhesion. This investigation is based on water peening of the substrate material before coating. The investigation revealed best results for diamond film adhesion on pretreated substrates compared to conventional diamond coatings on cemented carbide tools applied with the CVD hot-filament process. In final cutting tests with increased film adhesion trough water peened cutting tools an improved wear behavior was detected. (orig.)

Examining speed of processing of facial emotion recognition in individuals at ultra-high risk for psychosis

DEFF Research Database (Denmark)

Glenthøj, Louise Birkedal; Fagerlund, Birgitte; Bak, Nikolaj

2018-01-01

Emotion recognition is an aspect of social cognition that may be a key predictor of functioning and transition to psychosis in individuals at ultra-high risk (UHR) for psychosis ( Allott et al., 2014 ). UHR individuals exhibit deficits in accurately identifying facial emotions ( van Donkersgoed et...... al., 2015 ), but other potential anomalies in facial emotion recognition are largely unexplored. This study aimed to extend current knowledge on emotion recognition deficits in UHR individuals by examining: 1) whether UHR would display significantly slower facial emotion recognition than healthy...... controls, 2) whether an association between emotion recognition accuracy and emotion recognition latency is present in UHR, 3) the relationships between emotion recognition accuracy, neurocognition and psychopathology in UHR....

Development of refractive X-ray focusing optics at Diamond Light Source

Science.gov (United States)

Alianelli, L.; Sawhney, K. J. S.; Loader, I. M.; Jenkins, D. W. K.; Stevens, R.; Snigirev, A.; Snigireva, I.

2007-09-01

The Diamond Optics & Metrology Group and the collaborators at the STFC Central Microstructure Facility have initiated a program for the design and fabrication of in-line micro- and nano-focusing optics for synchrotron radiation beamlines. The first type of optics fabricated is a kinoform lens in silicon on the same model proposed by K. Evans- Lutterodt et al [Opt. Expr. 11 (2003) 919.]. The fabrication utilised ultra high resolution electron beam lithographic patterning of an electron sensitive SU8 polymer and deep reactive ion etching of silicon. The first test of the focusing properties was performed at the ESRF BM5 optics beamline. In this paper we present details on the design and fabrication, and discuss the test results.

Ductile cutting of silicon microstructures with surface inclination measurement and compensation by using a force sensor integrated single point diamond tool

International Nuclear Information System (INIS)

Chen, Yuan-Liu; Cai, Yindi; Shimizu, Yuki; Ito, So; Gao, Wei; Ju, Bing-Feng

2016-01-01

This paper presents a measurement and compensation method of surface inclination for ductile cutting of silicon microstructures by using a diamond tool with a force sensor based on a four-axis ultra-precision lathe. The X- and Y-directional inclinations of a single crystal silicon workpiece with respect to the X- and Y-motion axes of the lathe slides were measured respectively by employing the diamond tool as a touch-trigger probe, in which the tool-workpiece contact is sensitively detected by monitoring the force sensor output. Based on the measurement results, fabrication of silicon microstructures can be thus carried out directly along the tilted silicon workpiece by compensating the cutting motion axis to be parallel to the silicon surface without time-consuming pre-adjustment of the surface inclination or turning of a flat surface. A diamond tool with a negative rake angle was used in the experiment for superior ductile cutting performance. The measurement precision by using the diamond tool as a touch-trigger probe was investigated. Experiments of surface inclination measurement and ultra-precision ductile cutting of a micro-pillar array and a micro-pyramid array with inclination compensation were carried out respectively to demonstrate the feasibility of the proposed method. (paper)

The characteristics of ESR and 3-D TL spectra of diamonds

International Nuclear Information System (INIS)

Liu Shunsheng; Lu Xu; Fu Huifang

2003-01-01

Electron Spin Resonance (ESR) and 3-dimensional Thermoluminescence (3-D TL) spectra of natural diamond, high temperature-high pressure artificial diamond and high temperature-low pressure chemical vapor deposited (CVD) diamond were determined. The characteristics of spectra have been studied. It is found that isolated nitrogen, nitrogen exchange pair and nitrogen atom pair (S=1) are main forms of electron spin resonance nitrogen in natural and high temperature-high pressure artificial diamonds. The spectrum of CVD diamond is sampler, and contains only one peak caused by suspended bond of unsaturated carbon ones. For 3-D TL spectra, natural diamond has two peaks (∼370 nm and ∼510 nm) in 100-200 degree C temperature range, high temperature-high pressure artificial diamond only has ∼370 nm peak, and CVD diamond only has ∼500 nm peak. These characteristics would be useful for the quality inspection and classification of diamonds, as well as for the study of geologic actions associated with natural diamond

A low-cost, ultra-fast and ultra-low noise preamplifier for silicon avalanche photodiodes

Science.gov (United States)

Gasmi, Khaled

2018-02-01

An ultra-fast and ultra-low noise preamplifier for amplifying the fast and weak electrical signals generated by silicon avalanche photodiodes has been designed and developed. It is characterized by its simplicity, compactness, reliability and low cost of construction. A very wide bandwidth of 300 MHz, a very good linearity from 1 kHz to 280 MHz, an ultra-low noise level at the input of only 1.7 nV Hz-1/2 and a very good stability are its key features. The compact size (70 mm  ×  90 mm) and light weight (45 g), as well as its excellent characteristics, make this preamplifier very competitive compared to any commercial preamplifier. The preamplifier, which is a main part of the detection system of a homemade laser remote sensing system, has been successfully tested. In addition, it is versatile and can be used in any optical detection system requiring high speed and very low noise electronics.

New solid laser: Ceramic laser. From ultra stable laser to ultra high output laser

International Nuclear Information System (INIS)

Ueda, Kenichi

2006-01-01

An epoch-making solid laser is developed. It is ceramic laser, polycrystal, which is produced as same as glass and shows ultra high output. Ti 3+ :Al 2 O 3 laser crystal and the CPA (chirped pulse amplification) technique realized new ultra high output lasers. Japan has developed various kinds of ceramic lasers, from 10 -2 to 67 x 10 3 w average output, since 1995. These ceramic lasers were studied by gravitational radiation astronomy. The scattering coefficient of ceramic laser is smaller than single crystals. The new fast ignition method is proposed by Institute of Laser Engineering of Osaka University, Japan. Ultra-intense short pulse laser can inject the required energy to the high-density imploded core plasma within the core disassembling time. Ti 3+ :Al 2 O 3 crystal for laser, ceramic YAG of large caliber for 100 kW, transparent laser ceramic from nano-crystals, crystal grain and boundary layer between grains, the scattering coefficient of single crystal and ceramic, and the derived release cross section of Yb:YAG ceramic are described. (S.Y.)

Toroidal plasma enhanced CVD of diamond films

International Nuclear Information System (INIS)

Zvanya, John; Cullen, Christopher; Morris, Thomas; Krchnavek, Robert R.; Holber, William; Basnett, Andrew; Basnett, Robert; Hettinger, Jeffrey

2014-01-01

An inductively coupled toroidal plasma source is used as an alternative to microwave plasmas for chemical vapor deposition of diamond films. The source, operating at a frequency of 400 kHz, synthesizes diamond films from a mixture of argon, methane, and hydrogen. The toroidal design has been adapted to create a highly efficient environment for diamond film deposition: high gas temperature and a short distance from the sample to the plasma core. Using a toroidal plasma geometry operating in the medium frequency band allows for efficient (≈90%) coupling of AC line power to the plasma and a scalable path to high-power and large-area operation. In test runs, the source generates a high flux of atomic hydrogen over a large area, which is favorable for diamond film growth. Using a deposition temperature of 900–1050 °C and a source to sample distance of 0.1–2.0 cm, diamond films are deposited onto silicon substrates. The results showed that the deposition rate of the diamond films could be controlled using the sample temperature and source to sample spacing. The results also show the films exhibit good-quality polycrystalline diamond as verified by Raman spectroscopy, x-ray diffraction, and scanning electron microscopy. The scanning electron microscopy and x-ray diffraction results show that the samples exhibit diamond (111) and diamond (022) crystallites. The Raman results show that the sp 3 peak has a narrow spectral width (FWHM 12 ± 0.5 cm −1 ) and that negligible amounts of the sp 2 band are present, indicating good-quality diamond films

Evaluation report on the development of ultra-solid lubricant with cluster diamond; Cluster diamond wo riyoshita kotai junkatsu fukugo zairyo no kaihatsu hyoka hokokusho

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-03-01

The fiscal 1998-2000 results of efforts to develop cluster diamond (CD)-diffused solid lubricant composite materials expected to exhibit excellent lubrication are stated. Since friction greatly affects machine life and energy efficiency, friction reduction is an important task. Very hard and microscopic CD was utilized for the achievement of a friction coefficient of 0.08. A manufacturing technology for molds 10nm or smaller was developed, which enabled the development of a gear not larger than 8mm. The success will enable the operation of micromachines in the absence of lubrication which is impossible at present. A CD-aided functional layer creation technology was also developed. It is expected that the development and practical application of micromechanisms will make rapid progress in the 21st century. Much is expected from the creation, and goods with the achievement applied thereto, of advanced technologies whereinto non-lubrication, functional layer creation, and excellent heat conductivity are incorporated. It is quite significant that, since CD is available in any field as far as light-load low-speed sliding conditions are satisfied, sliding parts will be improved and service life will be prolonged. (NEDO)

Controlling Directional Liquid Motion on Micro- and Nanocrystalline Diamond/β-SiC Composite Gradient Films.

Science.gov (United States)

Wang, Tao; Handschuh-Wang, Stephan; Huang, Lei; Zhang, Lei; Jiang, Xin; Kong, Tiantian; Zhang, Wenjun; Lee, Chun-Sing; Zhou, Xuechang; Tang, Yongbing

2018-01-30

In this Article, we report the synthesis of micro- and nanocrystalline diamond/β-SiC composite gradient films, using a hot filament chemical vapor deposition (HFCVD) technique and its application as a robust and chemically inert means to actuate water and hazardous liquids. As revealed by scanning electron microscopy, the composition of the surface changed gradually from pure nanocrystalline diamond (hydrophobic) to a nanocrystalline β-SiC surface (hydrophilic). Transmission electron microscopy and Raman spectroscopy were employed to determine the presence of diamond, graphite, and β-SiC phases. The as-prepared gradient films were evaluated for their ability to actuate water. Indeed, water was transported via the gradient from the hydrophobic (hydrogen-terminated diamond) to the hydrophilic side (hydroxyl-terminated β-SiC) of the gradient surface. The driving distance and velocity of water is pivotally influenced by the surface roughness. The nanogradient surface showed significant promise as the lower roughness combined with the longer gradient yields in transport distances of up to 3.7 mm, with a maximum droplet velocity of nearly 250 mm/s measured by a high-speed camera. As diamond and β-SiC are chemically inert, the gradient surfaces can be used to drive hazardous liquids and reactive mixtures, which was signified by the actuation of hydrochloric acid and sodium hydroxide solution. We envision that the diamond/β-SiC gradient surface has high potential as an actuator for water transport in microfluidic devices, DNA sensors, and implants, which induce guided cell growth.

Ultra-High Speed Visualization of the Flashing Instability in Micron Size Nozzles under Vacuum Conditions

KAUST Repository

Alghamdi, Tariq A.

2017-11-01

I visualized the flash-boiling atomization of liquid jets released into a low pressure environment at frame rates of up to five million frames per second. Such a high temporal resolution allowed us to observe for the first time the bubble expansion mechanism that atomizes the jet. To visualize the dynamics in detail, I focused closely to the outflow of the nozzle using a long distance microscope objective. I documented an abrupt transition from a laminar to a fully external flashing jet by systematically reducing the ambient pressure. I performed experiments with different volatile liquids and using nozzles with different inner diameters. The inner diameters of the nozzles varied from 30 to 480 . Perfluorohexane (PFnH) was our main working fluid, but also methanol, ethanol and 1-bromopropane were tested. Surprisingly, minimum intensity profiles revealed spray angles close to ~360°, meaning drops are ejected in all directions. Also, I measured speeds of bubble expansion up to 140 m/s. That is 45 times faster than the upper bound for inertial growth speed in complete vacuum from the Rayleigh-Plesset equation. I also calculated the trajectories of the ejected droplets as well as the drop speed distribution using particle tracking. I expect that our results bring new insight into the flash-boiling atomization mechanism.

Charge collection characteristics of a super-thin diamond membrane detector measured with high-energy heavy ions

International Nuclear Information System (INIS)

Iwamoto, N.; Makino, T.; Onoda, S.; Ohshima, T.; Kamiya, T.; Kada, W.; Skukan, N.; Grilj, V.; Jaksic, M.; Pomorski, M.

2014-01-01

A transmission particle detector based on a super-thin diamond membrane film which can also be used simultaneously as a vacuum window for ion beam extraction has been developed. Charge collection characteristics of a μ-thick diamond membrane detector for high-energy heavy ions including 75 MeV Ne, 150 MeV Ar, 322 MeV Kr, and 454 MeV Xe have been investigated for the first time. Charge collection signals under single particle flux from the thin part are stable and are well distinguishable from background signals. This behavior suggests that the diamond membrane detector could be used for counting single ions. On the other hand, charge collection efficiency is found to decrease with increasing of charge generated in the diamond membrane detector. This suggests that the pulse height defect, which has been previously reported for Si and SiC detectors, also occurs in the diamond membrane detector. (authors)

Homo-epitaxial diamond film growth on ion implanted diamond substrates

Energy Technology Data Exchange (ETDEWEB)

Weiser, P S; Prawer, S; Nugent, K W; Bettiol, A A; Kostidis, L I; Jamieson, D N [Melbourne Univ., Parkville, VIC (Australia). School of Physics

1997-12-31

The nucleation of CVD diamond is a complicated process, governed by many interrelated parameters. In the present work we attempt to elucidate the effect of strain on the growth of a homo-epitaxial CVD diamond. We have employed laterally confined high dose (MeV) Helium ion implantation to produce surface swelling of the substrate. The strain is enhanced by the lateral confinement of the implanted region to squares of 100 x 100 {mu}m{sup 2}. After ion implantation, micro-Raman spectroscopy was employed to map the surface strain. The substrates were then inserted into a CVD reactor and a CVD diamond film was grown upon them. Since the strained regions were laterally confined, it was then possible to monitor the effect of strain on diamond nucleation. The substrates were also analysed using Rutherford Backscattering Spectroscopy (RBS), Proton induced X-ray Emission (PIXE) and Ion Beam induced Luminescence (IBIL). 7 refs., 5 figs.

Homo-epitaxial diamond film growth on ion implanted diamond substrates

Energy Technology Data Exchange (ETDEWEB)

Weiser, P.S.; Prawer, S.; Nugent, K.W.; Bettiol, A.A.; Kostidis, L.I.; Jamieson, D.N. [Melbourne Univ., Parkville, VIC (Australia). School of Physics

1996-12-31

The nucleation of CVD diamond is a complicated process, governed by many interrelated parameters. In the present work we attempt to elucidate the effect of strain on the growth of a homo-epitaxial CVD diamond. We have employed laterally confined high dose (MeV) Helium ion implantation to produce surface swelling of the substrate. The strain is enhanced by the lateral confinement of the implanted region to squares of 100 x 100 {mu}m{sup 2}. After ion implantation, micro-Raman spectroscopy was employed to map the surface strain. The substrates were then inserted into a CVD reactor and a CVD diamond film was grown upon them. Since the strained regions were laterally confined, it was then possible to monitor the effect of strain on diamond nucleation. The substrates were also analysed using Rutherford Backscattering Spectroscopy (RBS), Proton induced X-ray Emission (PIXE) and Ion Beam induced Luminescence (IBIL). 7 refs., 5 figs.

Homo-epitaxial diamond film growth on ion implanted diamond substrates

International Nuclear Information System (INIS)

Weiser, P.S.; Prawer, S.; Nugent, K.W.; Bettiol, A.A.; Kostidis, L.I.; Jamieson, D.N.

1996-01-01

The nucleation of CVD diamond is a complicated process, governed by many interrelated parameters. In the present work we attempt to elucidate the effect of strain on the growth of a homo-epitaxial CVD diamond. We have employed laterally confined high dose (MeV) Helium ion implantation to produce surface swelling of the substrate. The strain is enhanced by the lateral confinement of the implanted region to squares of 100 x 100 μm 2 . After ion implantation, micro-Raman spectroscopy was employed to map the surface strain. The substrates were then inserted into a CVD reactor and a CVD diamond film was grown upon them. Since the strained regions were laterally confined, it was then possible to monitor the effect of strain on diamond nucleation. The substrates were also analysed using Rutherford Backscattering Spectroscopy (RBS), Proton induced X-ray Emission (PIXE) and Ion Beam induced Luminescence (IBIL). 7 refs., 5 figs

Modified diamond dies for laser applications

Energy Technology Data Exchange (ETDEWEB)

McWilliams, R.A.

1978-06-21

A modified wire drawing die for spatial filtering techniques is described. It was designed for use in high power laser systems. The diamond aperture is capable of enduring high intensity laser frequency without damaging the laser beam profile. The diamond is mounted at the beam focus in a vacuum of 1 x 10/sup -5/ Torr. The vacuum prevents plasma forming at the diamond aperture, thus enabling the beam to pass through without damaging the holder or aperture. The spatial filters are fitted with a manipulator that has three electronic stepping motors, can position the aperture in three orthogonal directions, and is capable of 3.2 ..mu..m resolution. Shiva laser system is using 105 diamond apertures for shaping the High Energy Laser Beam.

Expectations for ultra-high energy interactions

International Nuclear Information System (INIS)

Feynman, R.P.

1978-01-01

Strong interactions at ultra-high energies are discussed with emphasis on the hadrons produced in high energy collisions. Evidence is considered that quantum chromodynamics might be the right theory, and also some estimates are given of quantum chromodynamics asymptotic-freedom phenomena, the work under discussion being very preliminary. 6 references

Tribological properties of nanocrystalline diamond films

Energy Technology Data Exchange (ETDEWEB)

Erdemir, A.; Fenske, G.R.; Krauss, A.R.; Gruen, D.M.; McCauley, T.; Csencsits, R.T. [Argonne National Lab., IL (United States). Energy Technology Div.

1999-11-01

In this paper, we present the friction and wear properties of nanocrystalline diamond (NCD) films grown in Ar-fullerene (C{sub 60}) and Ar-CH{sub 4} microwave plasmas. Specifically, we will address the fundamental tribological issues posed by these films during sliding against Si{sub 3}N{sub 4} counterfaces in ambient air and inert gases. Grain sizes of the films grown by the new method are very small (10-30 nm) and are much smoother (20-40 nm, root mean square) than those of films grown by the conventional H{sub 2}-CH{sub 4} microwave-assisted chemical vapor deposition process. Transmission electron microscopy (TEM) revealed that the grain boundaries of these films are very sharp and free of nondiamond phases. The microcrystalline diamond films grown by most conventional methods consist of large grains and a rough surface finish, which can cause severe abrasion during sliding against other materials. The friction coefficients of films grown by the new method (i.e. in Ar-C{sub 60} and Ar-CH{sub 4} plasmas) are comparable with those of natural diamond, and wear damage on counterface materials is minimal. Fundamental tribological studies indicate that these films may undergo phase transformation during long-duration, high-speed and/or high-load sliding tests and that the transformation products trapped at the sliding interfaces can intermittently dominate friction and wear performance. Using results from a combination of TEM, electron diffraction, Raman spectroscopy, and electron energy loss spectroscopy, we describe the structural chemistry of the debris particles trapped at the sliding interfaces and elucidate their possible effects on friction and wear of NCD films in dry N{sub 2}. Finally, we suggest a few potential applications in which NCD films can improve performance and service lives. (orig.)

High power millimeter wave experiment of torus diamond window prototype for ITER EC H and CD system

International Nuclear Information System (INIS)

Takahashi, K.; Kajiwara, K.; Oda, Y.; Sakamoto, K.; Omori, T.; Henderson, M.

2013-01-01

Highlights: ► The diamond window prototype was fabricated based on the reliable and manufacturable design. ► Transmission of 740 kW-100 s on the window prototype was successfully demonstrated. ► tan δ = 7.8 × 10 −6 , which was the lowest value that we had ever obtained at JAEA, was evaluated. ► The window structure promising the high power transmission more than 1 MW was obtained. -- Abstract: The design of the torus diamond window for the ITER electron cyclotron heating and current drive (EC H and CD) system has advanced considering a reliable and manufacturable structure. The diamond window prototype was fabricated based on the design and the high power experiment was carried out to verify the millimeter wave transmission capability. Transmission of 740 kW-100 s was demonstrated and no significant temperature increase of the window structure and no damage on the diamond disk were obtained. The temperature saturation of the cooling water for the window was observed and loss tangent of 7.8 × 10 −6 , which was the lowest value that we had ever obtained at JAEA, was evaluated. This result indicates that the diamond window design is feasible and promising the high power more than 1 MW transmission

Extending ultra-short pulse laser texturing over large area

Energy Technology Data Exchange (ETDEWEB)

Mincuzzi, G., E-mail: girolamo.mincuzzi@alphanov.com; Gemini, L.; Faucon, M.; Kling, R.

2016-11-15

Highlights: • We carried out metal surface texturing (Ripples, micro grooves, Spikes) using a high power, high repetition rate, industrial, Ultra-short pulses laser. • Extremely Fast processing is shown (Laser Scan speed as high as 90 m/s) with a polygon scanner head. • Stainless steel surface blackening with Ultra-short pulses laser has been obtained with unprecedented scanspeed. • Full SEM surface characterization was carried out for all the different structures obtained. • Reflectance measurements were carried out to characterize surface reflectance. - Abstract: Surface texturing by Ultra-Short Pulses Laser (UPL) for industrial applications passes through the use of both fast beam scanning systems and high repetition rate, high average power P, UPL. Nevertheless unwanted thermal effects are expected when P exceeds some tens of W. An interesting strategy for a reliable heat management would consists in texturing with a low fluence values (slightly higher than the ablation threshold) and utilising a Polygon Scanner Heads delivering laser pulses with unrepeated speed. Here we show for the first time that with relatively low fluence it is possible over stainless steel, to obtain surface texturing by utilising a 2 MHz femtosecond laser jointly with a polygonal scanner head in a relatively low fluence regime (0.11 J cm{sup −2}). Different surface textures (Ripples, micro grooves and spikes) can be obtained varying the scan speed from 90 m s{sup −1} to 25 m s{sup −1}. In particular, spikes formation process has been shown and optimised at 25 m s{sup −1} and a full morphology characterization by SEM has been carried out. Reflectance measurements with integrating sphere are presented to compare reference surface with high scan rate textures. In the best case we show a black surface with reflectance value < 5%.

Fabrication and testing of diamond-machined gratings in ZnSe, GaP, and bismuth germanate for the near infrared and visible

Energy Technology Data Exchange (ETDEWEB)

Kuzmenko, P J; Little, S L; Ikeda, Y; Kobayashi, N

2008-06-22

High quality immersion gratings for infrared applications have been demonstrated in silicon and germanium. To extend this technology to shorter wavelengths other materials must be investigated. We selected three materials, zinc selenide, gallium phosphide and bismuth germanate (Bi{sub 4}Ge{sub 3}O{sub 12}), based on high refractive index, good visible transmission and commercial availability in useful sizes. Crystal samples were diamond turned on an ultra-precision lathe to identify preferred cutting directions. Using this information we diamond-flycut test gratings over a range of feed rates to determine the optimal cutting conditions. For both ZnSe and GaP good surface quality was achieved at feed rates up to 1.0 cm/minute using a special compound angle diamond tool with negative rake angles on both cutting surfaces. The surface roughness of the groove facets was about 4 nm. A Zygo interferometer measured grating wavefront errors in reflection. For the ZnSe the RMS error was < {lambda}/20 at 633nm. More extensive testing was performed with a HeNe laser source and a cooled CCD camera. These measurements demonstrated high relative diffraction efficiency (> 80%), low random groove error (2.0 nm rms), and Rowland ghost intensities at < 0.1%. Preliminary tests on bismuth germanate show high tool wear.

Experimental Investigation of Magnetic Superconducting, and other Phase Transitions in Novel f-Electron Materials at Ultra-high Pressures Using Designer Diamond Anvils

International Nuclear Information System (INIS)

Maple, M. Brian

2005-01-01

Pressure is a powerful control parameter, owing to its ability to affect crystal and electronic structure without introducing defects, for the investigation of condensed matter systems. Some f-electron, heavy-fermion materials display interesting and novel behavior when exposed to pressures achievable with conventional experimental techniques; however, a growing number of condensed matter systems require extreme conditions such as ultrahigh pressures, high magnetic fields, and ultralow temperatures to sufficiently explore the important properties. To that end, we have been funded to develop an ultrahigh pressure facility at the University of California, San Diego (UCSD) in order to investigate superconductivity, magnetism, non-Fermi liquid behavior, and other phenomena under extreme conditions. Our goals for the second year of this grant were as follows: (a) perform electrical resistivity measurements on novel samples at a myriad of pressures using conventional piston-cylinder techniques, Bridgman anvil techniques, and diamond anvil cell technology; (b) install, commission, and operate an Oxford Kelvinox MX-100 dilution refrigerator for access to ultralow temperatures and high magnetic fields. (c) continue the development of diamond anvil cell (DAC) technology. During the past year, we have successfully installed the Oxford Kelvinox MX-100 dilution refrigerator and verified its operability down to 12 mK. We have begun an experimental program to systematically investigate the f-electron compound URu2Si2 under pressure and in the presence of magnetic fields. We have also continued our collaborative work with Sam Weir at Lawrence Livermore National Laboratory (LLNL) on Au4V and implemented a new corollary study on Au1-xVx using ultrahigh pressures. We have continued developing our DAC facility by designing and constructing an apparatus for in situ pressure measurement as well as designing high pressure cells. This report serves to highlight the progress we have made

Comparison of natural and synthetic diamond X-ray detectors.

Science.gov (United States)

Lansley, S P; Betzel, G T; Metcalfe, P; Reinisch, L; Meyer, J

2010-12-01

Diamond detectors are particularly well suited for dosimetry applications in radiotherapy for reasons including near-tissue equivalence and high-spatial resolution resulting from small sensitive volumes. However, these detectors have not become commonplace due to high cost and poor availability arising from the need for high-quality diamond. We have fabricated relatively cheap detectors from commercially-available synthetic diamond fabricated using chemical vapour deposition. Here, we present a comparison of one of these detectors with the only commercially-available diamond-based detector (which uses a natural diamond crystal). Parameters such as the energy dependence and linearity of charge with dose were investigated at orthovoltage energies (50-250 kV), and dose-rate dependence of charge at linear accelerator energy (6 MV). The energy dependence of a synthetic diamond detector was similar to that of the natural diamond detector, albeit with slightly less variation across the energy range. Both detectors displayed a linear response with dose (at 100 kV) over the limited dose range used. The sensitivity of the synthetic diamond detector was 302 nC/Gy, compared to 294 nC/Gy measured for the natural diamond detector; however, this was obtained with a bias of 246.50 V compared to a bias of 61.75 V used for the natural diamond detector. The natural diamond detector exhibited a greater dependency on dose-rate than the synthetic diamond detector. Overall, the synthetic diamond detector performed well in comparison to the natural diamond detector.

A comparison of diamond growth rate using in-liquid and conventional plasma chemical vapor deposition methods

International Nuclear Information System (INIS)

Takahashi, Yoshiyuki; Toyota, Hiromichi; Nomura, Shinfuku; Mukasa, Shinobu; Inoue, Toru

2009-01-01

In order to make high-speed deposition of diamond effective, diamond growth rates for gas-phase microwave plasma chemical vapor deposition and in-liquid microwave plasma chemical vapor deposition are compared. A mixed gas of methane and hydrogen is used as the source gas for the gas-phase deposition, and a methanol solution of ethanol is used as the source liquid for the in-liquid deposition. The experimental system pressure is in the range of 60-150 kPa. While the growth rate of diamond increases as the pressure increases, the amount of input microwave energy per unit volume of diamond is 1 kW h/mm 3 regardless of the method used. Since the in-liquid deposition method provides a superior cooling effect through the evaporation of the liquid itself, a higher electric input power can be applied to the electrodes under higher pressure environments. The growth rate of in-liquid microwave plasma chemical vapor deposition process is found to be greater than conventional gas-phase microwave plasma chemical vapor deposition process under the same pressure conditions.

A comparison of diamond growth rate using in-liquid and conventional plasma chemical vapor deposition methods

Science.gov (United States)

Takahashi, Yoshiyuki; Toyota, Hiromichi; Nomura, Shinfuku; Mukasa, Shinobu; Inoue, Toru

2009-06-01

In order to make high-speed deposition of diamond effective, diamond growth rates for gas-phase microwave plasma chemical vapor deposition and in-liquid microwave plasma chemical vapor deposition are compared. A mixed gas of methane and hydrogen is used as the source gas for the gas-phase deposition, and a methanol solution of ethanol is used as the source liquid for the in-liquid deposition. The experimental system pressure is in the range of 60-150 kPa. While the growth rate of diamond increases as the pressure increases, the amount of input microwave energy per unit volume of diamond is 1 kW h/mm3 regardless of the method used. Since the in-liquid deposition method provides a superior cooling effect through the evaporation of the liquid itself, a higher electric input power can be applied to the electrodes under higher pressure environments. The growth rate of in-liquid microwave plasma chemical vapor deposition process is found to be greater than conventional gas-phase microwave plasma chemical vapor deposition process under the same pressure conditions.

Temperature dependent simulation of diamond depleted Schottky PIN diodes

International Nuclear Information System (INIS)

Hathwar, Raghuraj; Dutta, Maitreya; Chowdhury, Srabanti; Goodnick, Stephen M.; Koeck, Franz A. M.; Nemanich, Robert J.

2016-01-01

Diamond is considered as an ideal material for high field and high power devices due to its high breakdown field, high lightly doped carrier mobility, and high thermal conductivity. The modeling and simulation of diamond devices are therefore important to predict the performances of diamond based devices. In this context, we use Silvaco ® Atlas, a drift-diffusion based commercial software, to model diamond based power devices. The models used in Atlas were modified to account for both variable range and nearest neighbor hopping transport in the impurity bands associated with high activation energies for boron doped and phosphorus doped diamond. The models were fit to experimentally reported resistivity data over a wide range of doping concentrations and temperatures. We compare to recent data on depleted diamond Schottky PIN diodes demonstrating low turn-on voltages and high reverse breakdown voltages, which could be useful for high power rectifying applications due to the low turn-on voltage enabling high forward current densities. Three dimensional simulations of the depleted Schottky PIN diamond devices were performed and the results are verified with experimental data at different operating temperatures

Temperature dependent simulation of diamond depleted Schottky PIN diodes

Science.gov (United States)

Hathwar, Raghuraj; Dutta, Maitreya; Koeck, Franz A. M.; Nemanich, Robert J.; Chowdhury, Srabanti; Goodnick, Stephen M.

2016-06-01

Diamond is considered as an ideal material for high field and high power devices due to its high breakdown field, high lightly doped carrier mobility, and high thermal conductivity. The modeling and simulation of diamond devices are therefore important to predict the performances of diamond based devices. In this context, we use Silvaco® Atlas, a drift-diffusion based commercial software, to model diamond based power devices. The models used in Atlas were modified to account for both variable range and nearest neighbor hopping transport in the impurity bands associated with high activation energies for boron doped and phosphorus doped diamond. The models were fit to experimentally reported resistivity data over a wide range of doping concentrations and temperatures. We compare to recent data on depleted diamond Schottky PIN diodes demonstrating low turn-on voltages and high reverse breakdown voltages, which could be useful for high power rectifying applications due to the low turn-on voltage enabling high forward current densities. Three dimensional simulations of the depleted Schottky PIN diamond devices were performed and the results are verified with experimental data at different operating temperatures

Temperature dependent simulation of diamond depleted Schottky PIN diodes

Energy Technology Data Exchange (ETDEWEB)

Hathwar, Raghuraj; Dutta, Maitreya; Chowdhury, Srabanti; Goodnick, Stephen M. [Department of Electrical Engineering, Arizona State University, Tempe, Arizona 85287-8806 (United States); Koeck, Franz A. M.; Nemanich, Robert J. [Department of Physics, Arizona State University, Tempe, Arizona 85287-8806 (United States)

2016-06-14

Diamond is considered as an ideal material for high field and high power devices due to its high breakdown field, high lightly doped carrier mobility, and high thermal conductivity. The modeling and simulation of diamond devices are therefore important to predict the performances of diamond based devices. In this context, we use Silvaco{sup ®} Atlas, a drift-diffusion based commercial software, to model diamond based power devices. The models used in Atlas were modified to account for both variable range and nearest neighbor hopping transport in the impurity bands associated with high activation energies for boron doped and phosphorus doped diamond. The models were fit to experimentally reported resistivity data over a wide range of doping concentrations and temperatures. We compare to recent data on depleted diamond Schottky PIN diodes demonstrating low turn-on voltages and high reverse breakdown voltages, which could be useful for high power rectifying applications due to the low turn-on voltage enabling high forward current densities. Three dimensional simulations of the depleted Schottky PIN diamond devices were performed and the results are verified with experimental data at different operating temperatures.

Test of a high-heat-load double-crystal diamond monochromator at the advanced photon source

International Nuclear Information System (INIS)

Fernandez, P.B.; Graber, T.; Lee, W.-K.; Mills, D.M.; Rogers, C.S.; Assoufid, L.

1997-01-01

We have tested the first diamond double-crystal monochromator at the advanced photon source (APS). The monochromator consisted of two synthetic type 1b (111) diamond plates in symmetric Bragg geometry. The single-crystal plates were 6 mm x 5 mm x 0.25 mm and 6 mm x 5 mm x 0.37 mm and showed a combination of mosaic spread/strain of the order of 2-4 arcsec over a central 1.4 mm-wide strip. The monochromator first crystal was indirectly cooled by edge contact with a water-cooled copper holder. We studied the performance of the monochromator under the high-power X-ray beam delivered by the APS undulator A. By changing the undulator gap, we varied the power incident on the first crystal and found no indication of thermal distortions or strains even at the highest incident power (200 W) and power density (108 W/mm 2 in normal incidence). The calculated maximum power and power density absorbed by the first crystal were 14.5 W and 2.4 W/mm 2 , respectively. We also compared the maximum intensity delivered by this monochromator and by a silicon (111) cryogenically cooled monochromator. For energies in the range 6-10 keV, the flux through the diamond monochromator was about a factor of two less than through the silicon monochromator, in good agreement with calculations. We conclude that water-cooled diamond monochromators can handle the high-power beams from the undulator beamlines at the APS. As single-crystal diamond plates of larger size and better quality become available, the use of diamond monochromators will become a very attractive option. (orig.)

Improved generation of single nitrogen-vacancy centers in diamond by ion implantation

Energy Technology Data Exchange (ETDEWEB)

Naydenov, Boris; Beck, Johannes; Steiner, Matthias; Balasubramanian, Gopalakrishnan; Jelezko, Fedor; Wrachtrup, Joerg [3. Institute of Physics, University of Stuttgart (Germany); Richter, Vladimir; Kalish, Rafi [Solid State Institute, Technion City, Haifa (Israel); Achard, Jocelyn [Laboratoire d' Ingenieurie des Materiaux et des Hautes Pressions, CNRS, Villetaneuse (France)

2010-07-01

Nitrogen-vacancy (NV) centers in diamond have recently attracted the attention of many research groups due to their possible application as quantum bits (qubits), ultra low magnetic field sensors and single photon sources. These color centers can be produced by nitrogen ion implantation, although the yield is usually below 5 % at low ion energies. Here we report an increase of the NV production efficiency by subsequently implanting carbon ions in the area of implanted nitrogen ions. This method improves the production yield by more than 50 %. We also show that very low nitrogen concentration (below 0.1 ppb) in diamond can be determined by converting the intrinsic nitrogen atoms to single NV centers and detecting the latter using a confocal microscope.

Low-temperature electrical transport in B-doped ultrananocrystalline diamond film

International Nuclear Information System (INIS)

Li, Lin; Zhao, Jing; Hu, Zhaosheng; Quan, Baogang; Li, Junjie; Gu, Changzhi

2014-01-01

B-doped ultrananocrystalline diamond (UNCD) films are grown using hot-filament chemical vapor deposition method, and their electrical transport properties varying with temperature are investigated. When the B-doped concentration of UNCD film is low, a step-like increase feature of the resistance is observed with decreasing temperature, reflecting at least three temperature-modified electronic state densities at the Fermi level according to three-dimensional Mott's variable range hopping transport mechanism, which is very different from that of reported B-doped nanodiamond. With increasing B-doped concentration, a superconductive transformation occurs in the UNCD film and the highest transformation temperature of 5.3 K is observed, which is higher than that reported for superconducting nanodiamond films. In addition, the superconducting coherence length is about 0.63 nm, which breaks a reported theoretical and experimental prediction about ultra-nanoscale diamond's superconductivity

Super Boiler: First Generation, Ultra-High Efficiency Firetube Boiler

Energy Technology Data Exchange (ETDEWEB)

None

2006-06-01

This factsheet describes a research project whose goal is to develop and demonstrate a first-generation ultra-high-efficiency, ultra-low emissions, compact gas-fired package boiler (Super Boiler), and formulate a long-range RD&D plan for advanced boiler technology out to the year 2020.

Diamond Fuzzy Number

Directory of Open Access Journals (Sweden)

T. Pathinathan

2015-01-01

Full Text Available In this paper we define diamond fuzzy number with the help of triangular fuzzy number. We include basic arithmetic operations like addition, subtraction of diamond fuzzy numbers with examples. We define diamond fuzzy matrix with some matrix properties. We have defined Nested diamond fuzzy number and Linked diamond fuzzy number. We have further classified Right Linked Diamond Fuzzy number and Left Linked Diamond Fuzzy number. Finally we have verified the arithmetic operations for the above mentioned types of Diamond Fuzzy Numbers.

Fabrication of Diamond Based Sensors for Use in Extreme Environments

Directory of Open Access Journals (Sweden)

Gopi K. Samudrala

2015-04-01

Full Text Available Electrical and magnetic sensors can be lithographically fabricated on top of diamond substrates and encapsulated in a protective layer of chemical vapor deposited single crystalline diamond. This process when carried out on single crystal diamond anvils employed in high pressure research is termed as designer diamond anvil fabrication. These designer diamond anvils allow researchers to study electrical and magnetic properties of materials under extreme conditions without any possibility of damaging the sensing elements. We describe a novel method for the fabrication of designer diamond anvils with the use of maskless lithography and chemical vapor deposition in this paper. This method can be utilized to produce diamond based sensors which can function in extreme environments of high pressures, high and low temperatures, corrosive and high radiation conditions. We demonstrate applicability of these diamonds under extreme environments by performing electrical resistance measurements during superconducting transition in rare earth doped iron-based compounds under high pressures to 12 GPa and low temperatures to 10 K.

Ion implantation into diamond

International Nuclear Information System (INIS)

Sato, Susumu

1994-01-01

The graphitization and the change to amorphous state of diamond surface layer by ion implantation and its characteristics are reported. In the diamond surface, into which more than 10 16 ions/cm 2 was implanted, the diamond crystals are broken, and the structure changes to other carbon structure such as amorphous state or graphite. Accompanying this change of structure, the electric conductivity of the implanted layer shows two discontinuous values due to high resistance and low resistance. This control of structure can be done by the temperature of the base during the ion implantation into diamond. Also it is referred to that by the base temperature during implantation, the mutual change of the structure between amorphous state and graphite can be controlled. The change of the electric resistance and the optical characteristics by the ion implantation into diamond surface, the structural analysis by Raman spectroscopy, and the control of the structure of the implanted layer by the base temperature during implantation are reported. (K.I.)

Use of the diamond to the detection of particles

International Nuclear Information System (INIS)

Mer, C.; Tromson, D.; Brambilla, A.; Foulon, F.; Guizard, B.; Bergonzo

2001-01-01

Diamond synthesized by chemical vapor deposition (CVD) is a valuable material for the detection of particles: broad forbidden energy band, high mobility of electron-hole pairs, and a short life-time of charge carriers. Diamond layers have been used in alpha detectors or gamma dose ratemeters designed to be used in hostile environment. Diamond presents a high resistance to radiation and corrosion. The properties of diamond concerning the detection of particles are spoilt by the existence of crystal defects even in high quality natural or synthesized diamond. This article presents recent works that have been performed in CEA laboratories in order to optimize the use of CVD diamond in particle detectors. (A.C.)

Diamond Pixel Detectors and 3D Diamond Devices

International Nuclear Information System (INIS)

Venturi, N.

2016-01-01

Results from detectors of poly-crystalline chemical vapour deposited (pCVD) diamond are presented. These include the first analysis of data of the ATLAS Diamond Beam Monitor (DBM). The DBM module consists of pCVD diamond sensors instrumented with pixellated FE-I4 front-end electronics. Six diamond telescopes, each with three modules, are placed symmetrically around the ATLAS interaction point. The DBM tracking capabilities allow it to discriminate between particles coming from the interaction point and background particles passing through the ATLAS detector. Also, analysis of test beam data of pCVD DBM modules are presented. A new low threshold tuning algorithm based on noise occupancy was developed which increases the DBM module signal to noise ratio significantly. Finally first results from prototypes of a novel detector using pCVD diamond and resistive electrodes in the bulk, forming a 3D diamond device, are discussed. 3D devices based on pCVD diamond were successfully tested with test beams at CERN. The measured charge is compared to that of a strip detector mounted on the same pCVD diamond showing that the 3D device collects significantly more charge than the planar device.

Polycrystalline Diamond Schottky Diodes and Their Applications.

Science.gov (United States)

Zhao, Ganming

In this work, four-hot-filament CVD techniques for in situ boron doped diamond synthesis on silicon substrates were extensively studied. A novel tungsten filament shape and arrangement used to obtain large-area, uniform, boron doped polycrystalline diamond thin films. Both the experimental results and radiative heat transfer analysis showed that this technique improved the uniformity of the substrate temperature. XRD, Raman and SEM studies indicate that large area, uniform, high quality polycrystalline diamond films were obtained. Schottky diodes were fabricated by either sputter deposition of silver or thermal evaporation of aluminum or gold, on boron doped diamond thin films. High forward current density and a high forward-to-reverse current ratio were exhibited by silver on diamond Schottky diodes. Schottky barrier heights and the majority carrier concentrations of both aluminum and gold contacted diodes were determined from the C-V measurements. Furthermore, a novel theoretical C-V-f analysis of deep level boron doped diamond Schottky diodes was performed. The analytical results agree well with the experimental results. Compressive stress was found to have a large effect on the forward biased I-V characteristics of the diamond Schottky diodes, whereas the effect on the reverse biased characteristics was relatively small. The stress effect on the forward biased diamond Schottky diode was attributed to piezojunction and piezoresistance effects. The measured force sensitivity of the diode was as high as 0.75 V/N at 1 mA forward bias. This result shows that CVD diamond device has potential for mechanical transducer applications. The quantitative photoresponse characteristics of the diodes were studied in the spectral range of 300 -1050 nm. Semi-transparent gold contacts were used for better photoresponse. Quantum efficiency as high as 50% was obtained at 500 nm, when a reverse bias of over 1 volt was applied. The Schottky barrier heights between either gold or

High-speed AC motors

Energy Technology Data Exchange (ETDEWEB)

Jokinen, T.; Arkkio, A. [Helsinki University of Technology Laboratory of Electromechanics, Otaniemi (Finland)

1997-12-31

The paper deals with various types of highspeed electric motors, and their limiting powers. Standard machines with laminated rotors can be utilised if the speed is moderate. The solid rotor construction makes it possible to reach higher power and speed levels than those of laminated rotors. The development work on high-speed motors done at Helsinki University of Technology is presented, too. (orig.) 12 refs.

SHMUTZ & PROTON-DIAMANT H + Irradiated/Written-Hyper/Super-conductivity(HC/SC) Precognizance/Early Experiments Connections: Wet-Graphite Room-Tc & Actualized MgB2 High-Tc: Connection to Mechanical Bulk-Moduli/Hardness: Diamond Hydrocarbon-Filaments, Disorder, Nano-Powders:C,Bi,TiB2,TiC

Science.gov (United States)

Wunderman, Irwin; Siegel, Edward Carl-Ludwig; Lewis, Thomas; Young, Frederic; Smith, Adolph; Dresschhoff-Zeller, Gieselle

2013-03-01

SHMUTZ: ``wet-graphite''Scheike-....[Adv.Mtls.(7/16/12)]hyper/super-SCHMUTZ-conductor(S!!!) = ``wet''(?)-``graphite''(?) = ``graphene''(?) = water(?) = hydrogen(?) =ultra-heavy proton-bands(???) = ...(???) claimed room/high-Tc/high-Jc superconductOR ``p''-``wave''/ BAND(!!!) superconductIVITY and actualized/ instantiated MgB2 high-Tc superconductors and their BCS- superconductivity: Tc Siegel[ICMAO(77);JMMM 7,190(78)] connection to SiegelJ.Nonxline-Sol.40,453(80)] disorder/amorphous-superconductivity in nano-powders mechanical bulk/shear(?)-moduli/hardness: proton-irradiated diamond, powders TiB2, TiC,{Siegel[Semis. & Insuls.5:39,47, 62 (79)])-...``VS''/concommitance with Siegel[Phys.Stat.Sol.(a)11,45(72)]-Dempsey [Phil.Mag. 8,86,285(63)]-Overhauser-(Little!!!)-Seitz-Smith-Zeller-Dreschoff-Antonoff-Young-...proton-``irradiated''/ implanted/ thermalized-in-(optimal: BOTH heat-capacity/heat-sink & insulator/maximal dielectric-constant) diamond: ``VS'' ``hambergite-borate-mineral transformable to Overhauser optimal-high-Tc-LiBD2 in Overhauser-(NW-periodic-table)-Land: CO2/CH4-ETERNAL-sequestration by-product: WATER!!!: physics lessons from

Comparative evaluation of CVD diamond technologies

Energy Technology Data Exchange (ETDEWEB)

Anthony, T.R. [General Electric Corporate Research & Development Center, Schenectady, NY (United States)

1993-01-01

Chemical vapor deposition (CVD) of diamonds occurs from hydrogen-hydrocarbon gas mixtures in the presence of atomic hydrogen at subatmospheric pressures. Most CVD methods are based on different means of generating and transporting atomic hydrogen in a particular system. Evaluation of these different techniques involves their capital costs, material costs, energy costs, labor costs and the type and quality of diamond that they produce. Currently, there is no universal agreement on which is the best technique and technique selection has been largely driven by the professional background of the user as well as the particular application of interest. This article discusses the criteria for evaluating a process for low-pressure deposition of diamond. Next, a brief history of low-pressure diamond synthesis is reviewed. Several specific processes are addressed, including the hot filament process, hot filament electron-assisted chemical vapor deposition, and plasma generation of atomic hydrogen by glow discharge, microwave discharge, low pressure radio frequency discharge, high pressure DC discharge, high pressure microwave discharge jets, high pressure RF discharge, and high and low pressure flames. Other types of diamond deposition methods are also evaluated. 101 refs., 15 figs.

CVD diamond for nuclear detection applications

International Nuclear Information System (INIS)

Bergonzo, P.; Brambilla, A.; Tromson, D.; Mer, C.; Guizard, B.; Marshall, R.D.; Foulon, F.

2002-01-01

Chemically vapour deposited (CVD) diamond is a remarkable material for the fabrication of radiation detectors. In fact, there exist several applications where other standard semiconductor detectors do not fulfil the specific requirements imposed by corrosive, hot and/or high radiation dose environments. The improvement of the electronic properties of CVD diamond has been under intensive investigations and led to the development of a few applications that are addressing specific industrial needs. Here, we report on CVD diamond-based detector developments and we describe how this material, even though of a polycrystalline nature, is readily of great interest for applications in the nuclear industry as well as for physics experiments. Improvements in the material synthesis as well as on device fabrication especially concern the synthesis of films that do not exhibit space charge build up effects which are often encountered in CVD diamond materials and that are highly detrimental for detection devices. On a pre-industrial basis, CVD diamond detectors have been fabricated for nuclear industry applications in hostile environments. Such devices can operate in harsh environments and overcome limitations encountered with the standard semiconductor materials. Of these, this paper presents devices for the monitoring of the alpha activity in corrosive nuclear waste solutions, such as those encountered in nuclear fuel assembly reprocessing facilities, as well as diamond-based thermal neutron detectors exhibiting a high neutron to gamma selectivity. All these demonstrate the effectiveness of a demanding industrial need that relies on the remarkable resilience of CVD diamond

Ultra high resolution tomography

Energy Technology Data Exchange (ETDEWEB)

Haddad, W.S.

1994-11-15

Recent work and results on ultra high resolution three dimensional imaging with soft x-rays will be presented. This work is aimed at determining microscopic three dimensional structure of biological and material specimens. Three dimensional reconstructed images of a microscopic test object will be presented; the reconstruction has a resolution on the order of 1000 A in all three dimensions. Preliminary work with biological samples will also be shown, and the experimental and numerical methods used will be discussed.

75 FR 81284 - Nationwide Use of High Frequency and Ultra High Frequency Active SONAR Technology; Draft...

Science.gov (United States)

2010-12-27

... Frequency and Ultra High Frequency Active SONAR Technology; Draft Programmatic Environmental Assessment and... Programmatic Environmental Assessment (PEA) for the Nationwide Use of High Frequency (HF) and Ultra High... potential impacts of each alternative on the human and natural environments. DATES: Comments and related...

High energy ion beam induced modifications in diamond and diamond like carbon thin films

International Nuclear Information System (INIS)

Dilawar, N.; Sah, S.; Mehta, B.R.; Vankar, V.D.

1996-01-01

Diamond and DLC films deposited using hot-filament chemical vapour deposition technique at various parameters were irradiated with 50 MeV Si 4+ ions. The resulting microstructural changes were studied using X-ray diffraction and scanning electron microscopy. All the samples showed the development of β-SiC and hexagonal carbon phases at the expense of the diamond/DLC phase. The ERD analysis was carried out to determine the hydrogen concentration and its distribution in DLC films. The absolute hydrogen concentration in DLC samples is of the order of 10 22 atoms/cm 3 which gets depleted on irradiation. The DLC samples show a clear dependence of hydrogen content on the deposition parameters. (author)

Very high pressure Moessbauer spectroscopy using diamond anvil cells

International Nuclear Information System (INIS)

Pasternak, M.P.; Taylor, R.D.

1988-01-01

The technique of generating very high pressure by means of Diamond Anvil Cells (DAC) for Mossbauer Effect applications is outlined. A comprehensive description is presented of the principles of DAC, modification for the use in M/umlt o/ssbauer Spectroscopy (MS), the Merrill--Bassett and Bassett cells, of pressure measurements, of gasketing and collimation, and of hydrostatic media. Examples of 151 Eu, 119 Sn and 129 I are given showing the feasibility of DAC applications in MS. Other isotopes with potential use for high pressure MS using DAC are suggested. 27 refs., 9 figs

Recent developments of high quality synthetic diamond single crystals for synchrotron X-ray monochromators

CERN Document Server

Freund, A K; Sellschop, J P Friedel; Burns, R C; Rebak, M

2001-01-01

For several years now, the ESRF, the University of the Witwatersrand and Messrs. De Beers Industrial Diamonds (Pty) Ltd. through their Diamond Research Laboratory, have pursued a development programme to assess and improve the quality of synthetic diamonds. Recently, in an effort to study the influence of nitrogen impurities on the defect structure, X-ray excited optical luminescence and spatially resolved double-crystal diffractometry were employed as new techniques. The correlation between nitrogen impurities and the raw defect structure was clearly visible. It was confirmed that concentration variations are related to lattice imperfections, where tilts are much more important than lattice constant variations. High reflectivity was observed and quite large zones of a sample bigger than 1 cm sup 2 showed to be perfect to within better than 0.5 arcsec.

EXAFS measurements under high pressure conditions using a combination of a diamond anvil cell and synchrotron radiation

International Nuclear Information System (INIS)

Sueno, Shigeho; Nakai, Izumi; Imafuku, Masayuki; Morikawa, Hideki; Kimata, Mitsuyoshi; Ohsumi, Kazumasa; Nomura, Masaharu; Shimomura, Osamu.

1986-01-01

EXAFS spectra for Fe, Co, Ni K-edges were successfully measured under high pressure conditions using a combination of a set of normal 1/8 carat diamond anvils, synchrotron radiation and a scintillation counter. A newly developed motor controlled goniometer stage was used for adjusting the position of a miniature diamond anvil cell. On the measurement of Cr and Mn spectra, specially designed thinner diamond anvil was necessary. EXAFS analysis of bis(dimethylglyoximato)nickel(II) at pressures from 1 atm to 5.6 GPa was made. (author)

High spatio-temporal resolution pollutant measurements of on-board vehicle emissions using ultra-fast response gas analyzers

Directory of Open Access Journals (Sweden)

M. Irwin

2018-06-01

Full Text Available Existing ultra-fast response engine exhaust emissions analyzers have been adapted for on-board vehicle use combined with GPS data. We present, for the first time, how high spatio-temporal resolution data products allow transient features associated with internal combustion engines to be examined in detail during on-road driving. Such data are both useful to examine the circumstances leading to high emissions, and reveals the accurate position of urban air quality hot spots as deposited by the candidate vehicle, useful for source attribution and dispersion modelling. The fast response time of the analyzers, which results in 100 Hz data, makes accurate time-alignment with the vehicle's engine control unit (ECU signals possible. This enables correlation with transient air fuel ratio, engine speed, load, and other engine parameters, which helps to explain the causes of the emissions spikes that portable emissions measurement systems (PEMS and conventional slow response analyzers would miss or smooth out due to mixing within their sampling systems. The data presented is from NO and NOx analyzers, but other fast analyzers (e.g. total hydrocarbons (THC, CO and CO2 can be used similarly. The high levels of NOx pollution associated with accelerating on entry ramps to motorways, driving over speed bumps, accelerating away from traffic lights, are explored in detail. The time-aligned ultra-fast analyzers offer unique insight allowing more accurate quantification and better interpretation of engine and driver activity and the associated emissions impact on local air quality.

High-Speed Interferometry Under Impacting Drops

KAUST Repository

Langley, Kenneth R.; Li, Erqiang; Thoroddsen, Sigurdur T

2017-01-01

Over the last decade the rapid advances in high-speed video technology, have opened up to study many multi-phase fluid phenomena, which tend to occur most rapidly on the smallest length-scales. One of these is the entrapment of a small bubble under a drop impacting onto a solid surface. Here we have gone from simply observing the presence of the bubble to detailed imaging of the formation of a lubricating air-disc under the drop center and its subsequent contraction into the bubble. Imaging the full shape-evolution of the air-disc has required μm and sub-μs space and time resolutions. Time-resolved 200 ns interferometry with monochromatic light, has allowed us to follow individual fringes to obtain absolute air-layer thicknesses, based on the eventual contact with the solid. We can follow the evolution of the dimple shape as well as the compression of the gas. The improved imaging has also revealed new levels of detail, like the nature of the first contact which produces a ring of micro-bubbles, highlighting the influence of nanometric surface roughness. Finally, for impacts of ultra-viscous drops we see gliding on ~100 nm thick rarified gas layers, followed by extreme wetting at numerous random spots.

High-Speed Interferometry Under Impacting Drops

KAUST Repository

Langley, Kenneth R.

2017-08-31

Over the last decade the rapid advances in high-speed video technology, have opened up to study many multi-phase fluid phenomena, which tend to occur most rapidly on the smallest length-scales. One of these is the entrapment of a small bubble under a drop impacting onto a solid surface. Here we have gone from simply observing the presence of the bubble to detailed imaging of the formation of a lubricating air-disc under the drop center and its subsequent contraction into the bubble. Imaging the full shape-evolution of the air-disc has required μm and sub-μs space and time resolutions. Time-resolved 200 ns interferometry with monochromatic light, has allowed us to follow individual fringes to obtain absolute air-layer thicknesses, based on the eventual contact with the solid. We can follow the evolution of the dimple shape as well as the compression of the gas. The improved imaging has also revealed new levels of detail, like the nature of the first contact which produces a ring of micro-bubbles, highlighting the influence of nanometric surface roughness. Finally, for impacts of ultra-viscous drops we see gliding on ~100 nm thick rarified gas layers, followed by extreme wetting at numerous random spots.

Chromatically encoded high-speed photography of cavitation bubble dynamics inside inhomogeneous ophthalmic tissue

Science.gov (United States)

Tinne, N.; Matthias, B.; Kranert, F.; Wetzel, C.; Krüger, A.; Ripken, T.

2016-03-01

The interaction effect of photodisruption, which is used for dissection of biological tissue with fs-laser pulses, has been intensively studied inside water as prevalent sample medium. In this case, the single effect is highly reproducible and, hence, the method of time-resolved photography is sufficiently applicable. In contrast, the reproducibility significantly decreases analyzing more solid and anisotropic media like biological tissue. Therefore, a high-speed photographic approach is necessary in this case. The presented study introduces a novel technique for high-speed photography based on the principle of chromatic encoding. For illumination of the region of interest within the sample medium, the light paths of up to 12 LEDs with various emission wavelengths are overlaid via optical filters. Here, MOSFET-electronics provide a LED flash with a duration diodes are externally triggered with a distinct delay for every LED. Furthermore, the different illumination wavelengths are chromatically separated again for detection via camera chip. Thus, the experimental setup enables the generation of a time-sequence of laser-tissue interaction inside anisotropic biological tissue and for the optimization of the surgical process with high-repetition rate fs-lasers. Additionally, this application is also suitable for the investigation of other microscopic, ultra-fast events in transparent inhomogeneous materials.

Shock characterization of an ultra-high strength concrete

International Nuclear Information System (INIS)

Erzar, B.; Pontiroli, C.; Buzaud, E.

2016-01-01

Nowadays, the design of protective structures may imply ultra-high performance concretes. These materials present a compressive strength 5 times higher than standard concretes. However, few reliable data on the shock response of such materials are available in the literature. Thus, a characterization of an ultra-high strength concrete has been conducted by means of hydrostatic and triaxial tests in the quasi-static regime, and plate impact experiments for shock response. Data have been gathered up to 6 GPa and a simple modelling approach has been applied to get a reliable representation of the shock compression of this concrete. (authors)

Diamond detectors for synchrotron radiation X-ray applications

Energy Technology Data Exchange (ETDEWEB)

De Sio, A. [Laboratori Nazionali di Frascati, INFN, 00044 Frascati, Roma (Italy); Department of Astronomy and Space Science, Universita di Firenze, L.go E. Fermi 2, 50125 Firenze (Italy)], E-mail: desio@arcetri.astro.it; Pace, E. [Department of Astronomy and Space Science, Universita di Firenze, L.go E. Fermi 2, 50125 Firenze (Italy); INFN, Sezione di Firenze, v. G. Sansone 1, Sesto Fiorentino, Firenze (Italy); Cinque, G.; Marcelli, A. [Laboratori Nazionali di Frascati, INFN, 00044 Frascati, Roma (Italy); Achard, J.; Tallaire, A. [LIMHP-CNRS, University of Paris XIII, 99 Avenue JB Clement, 93430 Villetaneuse (France)

2007-07-15

Due to its unique physical properties, diamond is a very appealing material for the development of electronic devices and sensors. Its wide band gap (5.5 eV) endows diamond based devices with low thermal noise, low dark current levels and, in the case of radiation detectors, high visible-to-X-ray signal discrimination (visible blindness) as well as high sensitivity to energies greater than the band gap. Furthermore, due to its radiation hardness diamond is very interesting for applications in extreme environments, or as monitor of high fluency radiation beams. In this work the use of diamond based detectors for X-ray sensing is discussed. On purpose, some photo-conductors based on different diamond types have been tested at the DAFNE-L synchrotron radiation laboratory at Frascati. X-ray sensitivity spectra, linearity and stability of the response of these diamond devices have been measured in order to evidence the promising performance of such devices.

Diamond detectors for synchrotron radiation X-ray applications

International Nuclear Information System (INIS)

De Sio, A.; Pace, E.; Cinque, G.; Marcelli, A.; Achard, J.; Tallaire, A.

2007-01-01

Due to its unique physical properties, diamond is a very appealing material for the development of electronic devices and sensors. Its wide band gap (5.5 eV) endows diamond based devices with low thermal noise, low dark current levels and, in the case of radiation detectors, high visible-to-X-ray signal discrimination (visible blindness) as well as high sensitivity to energies greater than the band gap. Furthermore, due to its radiation hardness diamond is very interesting for applications in extreme environments, or as monitor of high fluency radiation beams. In this work the use of diamond based detectors for X-ray sensing is discussed. On purpose, some photo-conductors based on different diamond types have been tested at the DAFNE-L synchrotron radiation laboratory at Frascati. X-ray sensitivity spectra, linearity and stability of the response of these diamond devices have been measured in order to evidence the promising performance of such devices

An atomic-scale and high efficiency finishing method of zirconia ceramics by using magnetorheological finishing

Science.gov (United States)

Luo, Hu; Guo, Meijian; Yin, Shaohui; Chen, Fengjun; Huang, Shuai; Lu, Ange; Guo, Yuanfan

2018-06-01

Zirconia ceramics is a valuable crucial material for fabricating functional components applied in aerospace, biology, precision machinery, military industry and other fields. However, the properties of its high brittleness and high hardness could seriously reduce its finishing efficiency and surface quality by conventional processing technology. In this work, we present a high efficiency and high-quality finishing process by using magnetorheological finishing (MRF), which employs the permanent magnetic yoke with straight air gap as excitation unit. The sub-nanoscale surface roughness and damage free surface can be obtained after magnetorheological finishing. The XRD results and SEM morphologies confirmed that the mechanical shear removal with ductile modes are the dominant material removal mechanism for the magnetorheological finishing of zirconia ceramic. With the developed experimental apparatus, the effects of workpiece speed, trough speed and work gap on material removal rate and surface roughness were systematically investigated. Zirconia ceramics finished to ultra-smooth surface with surface roughness less than Ra 1 nm was repeatedly achieved during the parametric experiments. Additionally, the highest material removal rate exceeded 1 mg/min when using diamond as an abrasive particle. Magnetorheological finishing promises to be an adaptable and efficient method for zirconia ceramics finishing.

Development of Diamond Tracking Detectors for High Luminosity Experiments at the LHC

CERN Multimedia

Kerbikov, B; Cumalat, J P; Mandic, I; Kagan, H P; Grigoriev, E; Mikuz, M; Oh, A; Martemiyanov, A; Golubev, A; Gorisek, A; Seidel, S C; Eusebi, R

2002-01-01

\\\\ \\\\% RD42 \\\\ \\\\Diamond, grown in a chemical vapour deposition process, can be used as a particle detector. The RD42 collaboration investigates its application in experiments at the Large Hadron Collider for particle tracking very close to the interaction region. Diamond is known to be radiation hard, in particular to photons and electrons up to at least 100 MRad. Irradiations with pions, protons and neutrons at room temperature show that diamond can resist higher fluences than silicon devices. An irradiation with 24 GeV/c protons on diamond samples shows no degradation up to fluences of 1 x 10$^{15} \\emph{p}$/cm$^{2}$ and a decrease in signal of only 40\\% at 5 x 10$^{15} \\emph{p}$/cm$^{2}$.\\\\ \\\\The signal response to a minimum ionizing particle in the best diamond samples is 9000 electon-hole-pairs which corresponds to a charge collection distance of 250 $\\mu$m.\\\\ \\\\Diamond strip detectors with sizes from 1 x 1 cm$^{2}$ to 2 x 4 cm$^{2}$ are routinely tested in particle beams using low noise VA readout elec...

Physical sciences at Diamond: past achievements and future opportunities.

Science.gov (United States)

McMorrow, D F

2015-03-06

The start of user operation at the Diamond Light Source in January 2007 marks a major milestone for the physical sciences in the UK. The routine delivery to the UK community of ultra-bright X-ray beams from the third-generation source has provided us with capabilities that were available previously only at international sources, and indeed has created some that are unique. Here, a personal view is given of some of the achievements to date, and possible future opportunities outlined. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Comparison of natural and synthetic diamond X-ray detectors

International Nuclear Information System (INIS)

Lansley, S. P.; Betzel, G.T.; Meyer, J.; Metcalf, P.; Reinisch, L.

2010-01-01

Full text: Diamond detectors are particularly well suited for dosimetry applications in radiotherapy for reasons including near-tissue equivalence and high-spatial resolu tion resulting from small sensitive volumes. However, these detectors have not become commonplace due to high cost and poor availability arising from the need for high quality diamond. We have fabricated relatively cheap detectors from commercially-available synthetic diamond fabricated using chemical vapour deposition. Here, we present a comparison of one of these detectors with the only commercially-available diamond-based detector (which uses a natural diamond crystal). Parameters such as the energy dependence and linearity of charge with dose were investigated at orthovoltage energies (50-250 kY), and dose-rate dependence of charge at linear accelerator energy (6 MY). The energy dependence of a synthetic diamond detector was similar to that of the natural diamond detector, albeit with slightly less variation across the energy range. Both detectors displayed a linear response S. P. Lansley () . G. T. Betzel . J. Meyer Department of Physics and Astronomy, University of Canterbury, Christchurch, New Zealand e-mail: stuart.lansley canterbury.ac.nz S. P. Lansley The Macdiarmid Institute for Advanced Materials and Nanotechnology, University of Canterbury, Christchurch, New Zealand P. Metcalfe Centre for Medical Radiation Physics, University of Wollongong, Wollongong, Australia L. Reinisch Department of Physical and Earth Sciences, Jacksonville State University, Jacksonville, AL, USA with dose (at 100 kY) over the limited dose range used. The sensitivity of the synthetic diamond detector was 302 nC/Gy, compared to 294 nC/Gy measured for the natural diamond detector; however, this was obtained with a bias of 246.50 Y compared to a bias of 61.75 Y used for the natural diamond detector. The natural diamond detector exhibited a greater dependency on dose-rate than the syn thetic diamond detector. Overall

Diamond Microchannel Heat Sink Designs For High Heat Flux Thermal Control

National Research Council Canada - National Science Library

Corbin, Michael

2002-01-01

.... Many investigators have suggested the use of diamond heat spreaders to reduce flux levels at or near to its source, and some have suggested that diamond microchannel heat sinks ultimately may play...

Polarised infrared cathodoluminescence from platelet defects in natural diamonds

International Nuclear Information System (INIS)

Kiflawi, I.; Lang, A.R.

1977-01-01

It is reported that the large platelet defects occasionally found in natural diamonds emit polarised cathodoluminescence in the near infrared. There is much uncertainty regarding the composition and structure of the platelets. New findings on the optical properties of the platelets are discussed. The discovery that cathodoluminescence from giant platelets can be seen in the near infrared using an image converter was followed up by photographic recording with Kodak high speed infrared films, and it was found that the infrared emission from the platelets is polarised in the platelet plane with a considerably higher polarisation ratio than in the case of their visible emissions. In order to assess the degree of polarisation of the infrared emission a Polaroid Type HR linear polariser was used, which is very effective at the longest wavelengths recorded by the Kodak high speed infrared film. The high degree of polarisation of the platelet infrared emission constitutes a well defined optical characteristic that any model for platelet structure, and for optical processes associated with platelets, must satisfactorily accommodate. (U.K.)

Diamond Growth in the Subduction Factory

Science.gov (United States)

Bureau, H.; Frost, D. J.; Bolfan-Casanova, N.; Leroy, C.; Estève, I.

2014-12-01

Natural diamonds are fabulous probes of the deep Earth Interior. They are the evidence of the deep storage of volatile elements, carbon at first, but also hydrogen and chlorine trapped as hydrous fluids in inclusions. The study of diamond growth processes in the lithosphere and mantle helps for our understanding of volatile elements cycling between deep reservoirs. We know now that inclusion-bearing diamonds similar to diamonds found in nature (i.e. polycrystalline, fibrous and coated diamonds) can grow in hydrous fluids or melts (Bureau et al., GCA 77, 202-214, 2012). Therefore, we propose that the best environment to promote such diamonds is the subduction factory, where highly hydrous fluids or melts are present. When oceanic plates are subducted in the lithosphere, they carry an oceanic crust soaked with seawater. While the slabs are traveling en route to the mantle, dehydration processes generate saline fluids highly concentrated in NaCl. In the present study we have experimentally shown that diamonds can grow from the saline fluids (up to 30 g/l NaCl in water) generated in subducted slabs. We have performed multi-anvil press experiments at 6-7 GPa and from 1300 to 1400°C during 6:00 hours to 30:00 hours. We observed large areas of new diamond grown in epitaxy on pure diamond seeds in salty hydrous carbonated melts, forming coated gems. The new rims are containing multi-component primary inclusions. Detailed characterizations of the diamonds and their inclusions have been performed and will be presented. These experimental results suggest that multi-component salty fluids of supercritical nature migrate with the slabs, down to the deep mantle. Such fluids may insure the first stage of the deep Earth's volatiles cycling (C, H, halogen elements) en route to the transition zone and the lower mantle. We suggest that the subduction factory may also be a diamond factory.

Ultra-high vacuum compatible optical chopper system for synchrotron x-ray scanning tunneling microscopy

Energy Technology Data Exchange (ETDEWEB)

Chang, Hao, E-mail: hc000211@ohio.edu [Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); Nanoscale and Quantum Phenomena Institute, Physics & Astronomy Department, Ohio University, Athens, Ohio 45701 (United States); Cummings, Marvin; Shirato, Nozomi; Stripe, Benjamin; Preissner, Curt; Freeland, John W. [Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); Rosenmann, Daniel [Center for Nanoscale Materials, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); Kersell, Heath; Hla, Saw-Wai [Nanoscale and Quantum Phenomena Institute, Physics & Astronomy Department, Ohio University, Athens, Ohio 45701 (United States); Center for Nanoscale Materials, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); Rose, Volker, E-mail: vrose@anl.gov [Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); Center for Nanoscale Materials, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States)

2016-01-28

High-speed beam choppers are a crucial part of time-resolved x-ray studies as well as a necessary component to enable elemental contrast in synchrotron x-ray scanning tunneling microscopy (SX-STM). However, many chopper systems are not capable of operation in vacuum, which restricts their application to x-ray studies with high photon energies, where air absorption does not present a significant problem. To overcome this limitation, we present a fully ultra-high vacuum (UHV) compatible chopper system capable of operating at variable chopping frequencies up to 4 kHz. The lightweight aluminum chopper disk is coated with Ti and Au films to provide the required beam attenuation for soft and hard x-rays with photon energies up to about 12 keV. The chopper is used for lock-in detection of x-ray enhanced signals in SX-STM.

An electron beam induced current study of gallium nitride and diamond materials

International Nuclear Information System (INIS)

Cropper, A.D.; Moore, D.J.; Scott, C.S.; Green, R.

1995-01-01

The continual need for microelectronic devices that operate under severe electronic and environmental conditions (high temperature, high frequency, high power, and radiation tolerance) has sustained research in wide bandgap semiconductor materials. The properties suggest these wide-bandgap semiconductor materials have tremendous potential for military and commercial applications. High frequency bipolar transistors and field effect transistors, diodes, and short wavelength optical devices have been proposed using these materials. Although research efforts involving the study of transport properties in Gallium Nitride (GaN) and Diamond have made significant advances, much work is still needed to improve the material quality so that the electrophysical behavior of device structures can be further understood and exploited. Electron beam induced current (EBIC) measurements can provide a method of understanding the transport properties in Gallium Nitride (GaN) and Diamond. This technique basically consists of measuring the current or voltage transient response to the drift and diffusion of carriers created by a short-duration pulse of radiation. This method differs from other experimental techniques because it is based on a fast transient electron beam probe created from a high speed, laser pulsed photoemission system

Sintering of ultra high molecular weight polyethylene

Indian Academy of Sciences (India)

Abstract. Ultra high molecular weight polyethylene (UHMWPE) is a high performance polymer having low coefficient of friction, good abrasion resistance, good chemical ... In this study, we report our results on compaction and sintering behaviour of two grades of UHMWPE with reference to the powder morphology, sintering ...

High rate operation of micro-strip gas chambers on diamond-coated glass

CERN Document Server

Bouclier, Roger; Million, Gilbert; Ropelewski, Leszek; Sauli, Fabio; Temmel, T; Cooke, R A; Donnel, S; Sastri, S A; Sonderer, N

1996-01-01

Very high rate operation of micro­strip gas chambers can be achieved using slightly conducting substrates. We describe preliminary measurements realized with detectors manufactured on boro-silicate glass coated, before the photo-lithographic processing, with a diamond layer having a surface resistivity of around 1014 ‡/o. Stable medium-term operation, and a rate capability largely exceeding the one obtained with identical plates manufactured on uncoated glass are demonstrated. If these results are confirmed by long-term measurements the diamond coating technology appears very attractive since it allows, with a moderate cost overhead, to use thin, commercially available glass with the required surface quality for the large-scale production of gas micro-strip detectors.

Mechanism and experimental research on ultra-precision grinding of ferrite

Science.gov (United States)

Ban, Xinxing; Zhao, Huiying; Dong, Longchao; Zhu, Xueliang; Zhang, Chupeng; Gu, Yawen

2017-02-01

Ultra-precision grinding of ferrite is conducted to investigate the removal mechanism. Effect of the accuracy of machine tool key components on grinding surface quality is analyzed. The surface generation model of ferrite ultra-precision grinding machining is established. In order to reveal the surface formation mechanism of ferrite in the process of ultraprecision grinding, furthermore, the scientific and accurate of the calculation model are taken into account to verify the grinding surface roughness, which is proposed. Orthogonal experiment is designed using the high precision aerostatic turntable and aerostatic spindle for ferrite which is a typical hard brittle materials. Based on the experimental results, the influence factors and laws of ultra-precision grinding surface of ferrite are discussed through the analysis of the surface roughness. The results show that the quality of ferrite grinding surface is the optimal parameters, when the wheel speed of 20000r/mm, feed rate of 10mm/min, grinding depth of 0.005mm, and turntable rotary speed of 5r/min, the surface roughness Ra can up to 75nm.

Diamonds: Exploration, mines and marketing

Science.gov (United States)

Read, George H.; Janse, A. J. A. (Bram)

2009-11-01

The beauty, value and mystique of exceptional quality diamonds such as the 603 carat Lesotho Promise, recovered from the Letseng Mine in 2006, help to drive a multi-billion dollar diamond exploration, mining and marketing industry that operates in some 45 countries across the globe. Five countries, Botswana, Russia, Canada, South Africa and Angola account for 83% by value and 65% by weight of annual diamond production, which is mainly produced by four major companies, De Beers, Alrosa, Rio Tinto and BHP Billiton (BHPB), which together account for 78% by value and 72% by weight of annual diamond production for 2007. During the last twelve years 16 new diamond mines commenced production and 4 re-opened. In addition, 11 projects are in advanced evaluation and may begin operations within the next five years. Exploration for diamondiferous kimberlites was still energetic up to the last quarter of 2008 with most work carried out in Canada, Angola, Democratic Republic of the Congo (DRC) and Botswana. Many kimberlites were discovered but no new economic deposits were outlined as a result of this work, except for the discovery and possible development of the Bunder project by Rio Tinto in India. Exploration methods have benefitted greatly from improved techniques of high resolution geophysical aerial surveying, new research into the geochemistry of indicator minerals and further insights into the formation of diamonds and the relation to tectonic/structural events in the crust and mantle. Recent trends in diamond marketing indicate that prices for rough diamonds and polished goods were still rising up to the last quarter of 2008 and subsequently abruptly sank in line with the worldwide financial crisis. Most analysts predict that prices will rise again in the long term as the gap between supply and demand will widen because no new economic diamond discoveries have been made recently. The disparity between high rough and polished prices and low share prices of publicly

Ultra-low noise supercontinuum source for ultra-high resolution optical coherence tomography at 1300 nm

Science.gov (United States)

Gonzalo, I. B.; Maria, M.; Engelsholm, R. D.; Feuchter, T.; Leick, L.; Moselund, P. M.; Podoleanu, A.; Bang, O.

2018-02-01

Supercontinuum (SC) sources are of great interest for many applications due to their ultra-broad optical bandwidth, good beam quality and high power spectral density [1]. In particular, the high average power over large bandwidths makes SC light sources excellent candidates for ultra-high resolution optical coherence tomography (UHR-OCT) [2-5]. However, conventional SC sources suffer from high pulse-to-pulse intensity fluctuations as a result of the noise-sensitive nonlinear effects involved in the SC generation process [6-9]. This intensity noise from the SC source can limit the performance of OCT, resulting in a reduced signal-to-noise ratio (SNR) [10-12]. Much work has been done to reduce the noise of the SC sources for instance with fiber tapers [7,8] or increasing the repetition rate of the pump laser for averaging in the spectrometer [10,12]. An alternative approach is to use all-normal dispersion (ANDi) fibers [13,14] to generate SC light from well-known coherent nonlinear processes [15-17]. In fact, reduction of SC noise using ANDi fibers compared to anomalous dispersion SC pumped by sub-picosecond pulses has been recently demonstrated [18], but a cladding mode was used to stabilize the ANDi SC. In this work, we characterize the noise performance of a femtosecond pumped ANDi based SC and a commercial SC source in an UHR-OCT system at 1300 nm. We show that the ANDi based SC presents exceptional noise properties compared to a commercial source. An improvement of 5 dB in SNR is measured in the UHR-OCT system, and the noise behavior resembles that of a superluminiscent diode. This preliminary study is a step forward towards development of an ultra-low noise SC source at 1300 nm for ultra-high resolution OCT.

Fabrication of High Thermal Conductivity NARloy-Z-Diamond Composite Combustion Chamber Liner for Advanced Rocket Engines

Science.gov (United States)

Bhat, Biliyar N.; Greene, Sandra E.; Singh, Jogender

2016-01-01

This paper describes the process development for fabricating a high thermal conductivity NARloy-Z-Diamond composite (NARloy-Z-D) combustion chamber liner for application in advanced rocket engines. The fabrication process is challenging and this paper presents some details of these challenges and approaches used to address them. Prior research conducted at NASA-MSFC and Penn State had shown that NARloy-Z-40%D composite material has significantly higher thermal conductivity than the state of the art NARloy-Z alloy. Furthermore, NARloy-Z-40 %D is much lighter than NARloy-Z. These attributes help to improve the performance of the advanced rocket engines. Increased thermal conductivity will directly translate into increased turbopump power, increased chamber pressure for improved thrust and specific impulse. Early work on NARloy-Z-D composites used the Field Assisted Sintering Technology (FAST, Ref. 1, 2) for fabricating discs. NARloy-Z-D composites containing 10, 20 and 40vol% of high thermal conductivity diamond powder were investigated. Thermal conductivity (TC) data. TC increased with increasing diamond content and showed 50% improvement over pure copper at 40vol% diamond. This composition was selected for fabricating the combustion chamber liner using the FAST technique.

High speed heterostructure devices

CERN Document Server

Beer, Albert C; Willardson, R K; Kiehl, Richard A; Sollner, T C L Gerhard

1994-01-01

Volume 41 includes an in-depth review of the most important, high-speed switches made with heterojunction technology. This volume is aimed at the graduate student or working researcher who needs a broad overview andan introduction to current literature. Key Features * The first complete review of InP-based HFETs and complementary HFETs, which promise very low power and high speed * Offers a complete, three-chapter review of resonant tunneling * Provides an emphasis on circuits as well as devices.

Lateral overgrowth of diamond film on stripes patterned Ir/HPHT-diamond substrate

Science.gov (United States)

Wang, Yan-Feng; Chang, Xiaohui; Liu, Zhangcheng; Liu, Zongchen; Fu, Jiao; Zhao, Dan; Shao, Guoqing; Wang, Juan; Zhang, Shaopeng; Liang, Yan; Zhu, Tianfei; Wang, Wei; Wang, Hong-Xing

2018-05-01

Epitaxial lateral overgrowth (ELO) of diamond films on patterned Ir/(0 0 1)HPHT-diamond substrates have been carried out by microwave plasma CVD system. Ir/(0 0 1)HPHT-diamond substrates are fabricated by photolithographic and magnetron sputtering technique. The morphology of the as grown ELO diamond film is characterized by optical microscopy and scanning electronic microscopy. The quality and stress of the ELO diamond film are investigated by surface etching pit density and micro-Raman spectroscopy. Two ultraviolet photodetectors are fabricated on ELO diamond area and non-ELO diamond area prepared on same substrate, and that one on ELO diamond area indicates better photoelectric properties. All results indicate quality of ELO diamond film is improved.

A sampling ultra-high-speed streak camera based on the use of a unique photomultiplier

International Nuclear Information System (INIS)

Marode, Emmanuel

An apparatus reproducing the ''streak'' mode of a high-speed camera is proposed for the case of a slit AB whose variations in luminosity are repetitive. A photomultiplier, analysing the object AB point by point, and a still camera, photographing a slit fixed on the oscilloscope screen parallel to the sweep direction are placed on a mobile platform P. The movement of P assures a time-resolved analysis of AB. The resolution is of the order of 2.10 -9 s, and can be improved [fr

Diamond nanowires: fabrication, structure, properties, and applications.

Science.gov (United States)

Yu, Yuan; Wu, Liangzhuan; Zhi, Jinfang

2014-12-22

C(sp(3) )C-bonded diamond nanowires are wide band gap semiconductors that exhibit a combination of superior properties such as negative electron affinity, chemical inertness, high Young's modulus, the highest hardness, and room-temperature thermal conductivity. The creation of 1D diamond nanowires with their giant surface-to-volume ratio enhancements makes it possible to control and enhance the fundamental properties of diamond. Although theoretical comparisons with carbon nanotubes have shown that diamond nanowires are energetically and mechanically viable structures, reproducibly synthesizing the crystalline diamond nanowires has remained challenging. We present a comprehensive, up-to-date review of diamond nanowires, including a discussion of their synthesis along with their structures, properties, and applications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Diamond-based heat spreaders for power electronic packaging applications

Science.gov (United States)

Guillemet, Thomas

As any semiconductor-based devices, power electronic packages are driven by the constant increase of operating speed (higher frequency), integration level (higher power), and decrease in feature size (higher packing density). Although research and innovation efforts have kept these trends continuous for now more than fifty years, the electronic packaging technology is currently facing a challenge that must be addressed in order to move toward any further improvements in terms of performances or miniaturization: thermal management. Thermal issues in high-power packages strongly affect their reliability and lifetime and have now become one of the major limiting factors of power modules development. Thus, there is a strong need for materials that can sustain higher heat flux levels while safely integrating into the electronic package architecture. In such context, diamond is an attractive candidate because of its outstanding thermal conductivity, low thermal expansion, and high electrical resistivity. Its low heat capacity relative to metals such as aluminum or copper makes it however preferable for heat spreading applications (as a heat-spreader) rather than for dissipating the heat flux itself (as a heat sink). In this study, a dual diamond-based heat-spreading solution is proposed. Polycrystalline diamond films were grown through laser-assisted combustion synthesis on electronic substrates (in the U.S) while, in parallel, diamond-reinforced copper-matrix composite films were fabricated through tape casting and hot pressing (in France). These two types of diamond-based heat-spreading films were characterized and their microstructure and chemical composition were related to their thermal performances. Particular emphasize was put on the influence of interfaces on the thermal properties of the materials, either inside a single material (grain boundaries) or between dissimilar materials (film/substrate interface, matrix/reinforcement interface). Finally, the packaging

Diamond-Based Supercapacitors: Realization and Properties.

Science.gov (United States)

Gao, Fang; Nebel, Christoph E

2016-10-26

In this Spotlight on Applications, we describe our recent progress on the fabrication of surface-enlarged boron-doped polycrystalline diamond electrodes, and evaluate their performance in supercapacitor applications. We begin with a discussion of the fabrication methods of porous diamond materials. The diamond surface enlargement starts with a top-down plasma etching method. Although the extra surface area provided by surface roughening or nanostructuring provides good outcome for sensing applications, a capacitance value <1 mF cm -2 or a surface-enlargement factor <100 fail to meet the requirement of a practical supercapacitor. Driven by the need for large surface areas, we recently focused on the tempated-growth method. We worked on both supported and free-standing porous diamond materials to enhance the areal capacitance to the "mF cm -2 " range. With our newly developed free-standing diamond paper, areal capacitance can be multiplied by stacking multilayers of the electrode material. Finally, considering the fact that there is no real diamond-based supercapacitor device up to now, we fabricated the first prototype pouch-cell device based on the free-standing diamond paper to evaluate its performance. The results reveal that the diamond paper is suitable for operation in high potential windows (up to 2.5 V) in aqueous electrolyte with a capacitance of 0.688 mF cm -2 per layer of paper (or 0.645 F g -1 ). Impedance spectroscopy revealed that the operation frequency of the device exceeds 30 Hz. Because of the large potential window and the ability to work at high frequency, the specific power of the device reached 1 × 10 5 W kg -1 . In the end, we made estimations on the future target performance of diamond supercapacitors based on the existing information.

Fiscal 1998 R and D report on femtosecond technology (ultra-short pulse optoelectronics technology); 1998 nendo femuto byo technology no kenkyu kaihatsu (chotan pulse hikari electronics gijutsu kaihatsu) seika hokokusho

Energy Technology Data Exchange (ETDEWEB)

NONE

1999-03-01

This report reports the result of the fiscal 1998 R and D on femtosecond technology supported by NEDO. For creation of industrial basic technologies supporting the advanced information society in the 21st century, ultra-high speed electronics technology including new functions beyond the speed limit of conventional electronics technologies is indispensable. From such viewpoint, this R and D aims at establishment of the basic technology necessary for ultra- high speed electronics technology through R and D of technology controlling conditions of beams and electrons in a femtosecond (10{sup -15}-10{sup -12} seconds) region. In fiscal 1998, this project first succeeded in fabrication of a prototype pulse compressor by using semiconductors, and developed a new pulse compressing method by using fibers to generate ultra-short pulse of 38fs. By developing new materials for intersubband transition where ultra-high speed responses can be expected, optical absorption by intersubband transition was first confirmed at optical communication wavelength. The main result for every theme is reported and explained. (NEDO)

Stagnant zone formation on diamond cutting tools during machining

International Nuclear Information System (INIS)

Izman, S.; Tamin, M.N.; Mon, T.T.; Venkatesh, V.C.; Shaharoun, A.M.

2007-01-01

Formation of an intact region on the rake face of cutting tool during machining is quite common phenomenon but its significance in maintaining tool edge sharpness has not been recognized by many researchers. This region is sometimes called stagnant zone. It is believed that when an intact zone present on the rake face, it delays the crater wear progress and hence maintaining the tool edge sharpness longer. This paper investigates the effect of edge radius, surface roughness of the rake face and cutting parameters on the formation of stagnant zone on two different type of diamond tools i.e. polycrystalline diamond PCD-KD100 and diamond-coated inserts when machining titanium alloy. The used inserta and post-processed chips were examined under FESEM and optical microscope after cutting at three different conditions. Experimental results show that the speed and feel, the tool edge radius, and the tool rake surface roughness significantly affect the stagnant zone formation. (author)

Laser spectroscopy of highly doped NV- centers in diamond

Science.gov (United States)

Subedi, Shova D.; Fedorov, Vladimir V.; Peppers, Jeremy; Martyshkin, Dmitry V.; Mirov, Sergey B.; Shao, Linbo; Loncar, Marko

2018-02-01

In this paper, prospects of using diamond with NV- centers as a gain medium have been studied. Spectroscopic characterization of NV- centers in diamond as well as absorption saturation and pump-probe experiments have been carried out. Absorption and emission cross-sections were estimated to be 2.8 × 10-17 cm2 and 4.3 × 10-17 cm2 at the maximum of absorption and emission bands, respectively. It was observed from emission spectra under pulse excitation that some NV- are photoionized to NV0 centers with ZPL at 575 nm. Room temperature luminescence lifetime of NV- centers was measured to be 12ns, which is close to the previously reported lifetime in bulk diamond ( 13ns). Saturated transmission was only about 11% of calculated values even at energy fluence much higher than the saturation flux. Two excited state absorptions (ESAs) with different relaxation times ("fast-decay" and "slow-decay with relaxation times of 500 ns and several tens of microseconds, respectively) were revealed in transmission decay kinetics at 632 nm. Kinetics of transmission at 670 nm was dominated by "slow-decay" ESA process. Kinetics of dk/k0 in shorter wavelength were strongly dominated by "fast-decay" ESA process. These results definitively indicate that stimulated emission of NV- centers is suppressed by photoionization and ESAs and the possibility of diamond lasers based on NV- centers is low.

Pushing the boundaries of high power lasers: low loss, large area CVD diamond

Science.gov (United States)

Wickham, Benjamin; Schoofs, Frank; Olsson-Robbie, Stefan; Bennett, Andrew; Balmer, Richard

2018-02-01

Synthetic CVD diamond has exceptional properties, including broad spectral transmission, physical and chemical robustness, and the highest thermal conductivity of any known material, making diamond an attractive material for medium to high power optical and laser applications, minimizing the detrimental effects of thermal lensing and radiation damage. Example applications include ATR prisms, Raman laser crystals, extra- and intra-cavity laser cooling. In each case the demands on the fundamental material properties and fabrication routes are slightly different. In recent years, there has been good progress in the development of low-loss, single crystal diamond, suitable for higher power densities, higher pulse rates and more demanding intra- and extra-cavity thermal management. The adoption of single crystal diamond in this area has however, been hindered by the availability of large area, low birefringence plates. To address this, we report a combination of CVD growth and processing methods that have enabled the manufacture of large, low defect substrates. A final homoepitaxial, low absorption synthesis stage has produced plates with large area (up to 16 mm edge length), low absorption (α<0.005 cm-1 at 1064 nm), and low birefringence (Δn <10-5), suitable for double-sided intra-cavity cooling. We demonstrate the practical advances in synthesis, including increasing the size while reducing in-use losses compared to previous generations of single crystal material, and practical developments in processing and implementation of the single crystal diamond parts, optimizing them for use in a state-of-the-art femto-second pulsed Ti:Sa thin disk gain module, all made in collaboration with the wider European FP7 funded Ti:Sa TD consortium.

A diamond-anvil high-pressure cell for X-ray diffraction on a single crystal

International Nuclear Information System (INIS)

Malinowski, M.

1987-01-01

A new diamond-anvil high-pressure cell is described which can be used in single-crystal X-ray diffraction instruments to collect X-ray intensity data from single-crystal samples up to hydrostatic pressures of about 10 GPa. A unique design allows two types of diffraction geometry to be applied in single-crystal high-pressure diffraction experiments. More than 85% of the Ewald sphere is accessible, and a continuous range of 2θ values is available from 0 up to about 160 0 . Pressure may be calibrated by the ruby fluorescence technique or by the use of an internal X-ray-standard single crystal. The design of our diamond-anvil cell would allow, with little or no modification, operation at high and low temperatures, optical studies and powder diffractometer work. (orig.)

Ultra-high Efficiency DC-DC Converter using GaN Devices

DEFF Research Database (Denmark)

Ramachandran, Rakesh

2016-01-01

properties of GaN devices can be utilized in power converters to make them more compact and highly efficient. This thesis entitled “Ultra-high Efficiency DC-DC Converter using GaN devices” focuses on achieving ultra-high conversion efficiency in an isolated dc-dc converter by the optimal utilization of Ga...... for many decades. However, the rate of improvement slowed as the silicon power materials asymptotically approached its theoretical bounds. Compared to Si, wideband gap materials such as Silicon Carbide (SiC) and Gallium Nitride (GaN) are promising semiconductors for power devices due to their superior...... in this thesis. Efficiency measurements from the hardware prototype of both the topologies are also presented in this thesis. Finally, the bidirectional operation of an optimized isolated dc-dc converter is presented. The optimized converter has achieved an ultra-high efficiency of 98.8% in both directions...

Ultra-high energy cosmic rays and prompt TeV gamma rays from ...

Indian Academy of Sciences (India)

physics pp. 789-792. Ultra-high energy cosmic rays and prompt. TeV gamma rays from gamma ray bursts ... The origin of the observed ultra-high energy cosmic ray (UHECR) events with ... are proton and electron rest mass, respectively.

Scaling violations at ultra-high energies

International Nuclear Information System (INIS)

Tung, W.K.

1979-01-01

The paper discusses some of the features of high energy lepton-hadron scattering, including the observed (Bjorken) scaling behavior. The cross-sections where all hadron final states are summed over, are examined and the general formulas for the differential cross-section are examined. The subjects of scaling, breaking and phenomenological consequences are studied, and a list of what ultra-high energy neutrino physics can teach QCD is given

A Review on the Low-Dimensional and Hybridized Nanostructured Diamond Films

Directory of Open Access Journals (Sweden)

Hongdong Li

2015-01-01

Full Text Available In the last decade, besides the breakthrough of high-rate growth of chemical vapor deposited single-crystal diamonds, numerous nanostructured diamond films have been rapidly developed in the research fields of the diamond-based sciences and industrial applications. The low-dimensional diamonds of two-dimensional atomic-thick nanofilms and nanostructural diamond on the surface of bulk diamond films have been theoretically and experimentally investigated. In addition, the diamond-related hybrid nanostructures of n-type oxide/p-type diamond and n-type nitride/p-type diamond, having high performance physical and chemical properties, are proposed for further applications. In this review, we first briefly introduce the three categories of diamond nanostructures and then outline the current advances in these topics, including their design, fabrication, characterization, and properties. Finally, we address the remaining challenges in the research field and the future activities.

Diamond identifaction

International Nuclear Information System (INIS)

1976-01-01

X-ray topography on diamonds allows for unique identification of diamonds. The method described consists of the registration of crystal defects, inclusions etc. of a diamond, resulting in a 'finger print' of the individual jewel which can only be changed by its complete destruction

CVD diamond substrates for electronic devices

International Nuclear Information System (INIS)

Holzer, H.

1996-03-01

In this study the applicability of chemical vapor deposition (CVD) diamond as a material for heat spreaders was investigated. Economical evaluations on the production of heat spreaders were also performed. For the diamond synthesis the hot-filament and microwave method were used respectively. The deposition parameters were varied in a way that free standing diamond layers with a thickness of 80 to 750 microns and different qualities were obtained. The influence of the deposition parameters on the relevant film properties was investigated and discussed. With both the hot-filament and microwave method it was possible to deposit diamond layers having a thermal conductivity exceeding 1200 W/mK and therefore to reach the quality level for commercial uses. The electrical resistivity was greater than 10 12 Ωcm. The investigation of the optical properties was done by Raman-, IR- and cathodoluminescence spectroscopy. Because of future applications of diamond-aluminium nitride composites as highly efficient heat spreaders diamond deposition an AIN was investigated. An improved substrate pretreatment prior to diamond deposition showed promising results for better performance of such composite heat spreaders. Both free standing layers and diamond-AIN composites could be cut by a CO2 Laser in Order to get an exact size geometry. A reduction of the diamond surface roughness was achieved by etching with manganese powder or cerium. (author)

Diamond growth in oxygen-acetylene flame

International Nuclear Information System (INIS)

Haga, Mario S.; Nagai, Y. Ernesto; Suzuki, Carlos K.

1995-01-01

What was supposed to be a laboratory curiosity in the 80's, in recent years the low pressure process for the production of man-made diamond turned out to be a major target for research and development of many high-tech companies. The main reason for such an interest stems on the possibility of coating many materials with a diamond film possessing the same amazing properties of the bulk natural diamond. Polycrystalline diamond film has been deposited on Mo substrate by using oxygen-acetylene flame of a welding torch. The substrate temperature has been held constant about 700 d eg C by means of a water cooled mount designed properly. Precision flowmeters have been used to control the flow ratio oxygen/acetylene, a key parameter for the success in diamond growth. Diamond has been detected by X-ray diffraction, a fast foolproof technique for crystal identification. Another method of analysis often used in Raman spectroscopy, which is able to exhibit amorphous structure besides crystalline phase. (author)

Copper-micrometer-sized diamond nanostructured composites

International Nuclear Information System (INIS)

Nunes, D; Livramento, V; Fernandes, H; Silva, C; Carvalho, P A; Shohoji, N; Correia, J B

2011-01-01

Reinforcement of a copper matrix with diamond enables tailoring the properties demanded for thermal management applications at high temperature, such as the ones required for heat sink materials in low activated nuclear fusion reactors. For an optimum compromise between thermal conductivity and mechanical properties, a novel approach based on multiscale diamond dispersions is proposed: a Cu-nanodiamond composite produced by milling is used as a nanostructured matrix for further dispersion of micrometer-sized diamond (μDiamond). A series of Cu-nanodiamond mixtures have been milled to establish a suitable nanodiamond fraction. A refined matrix with homogeneously dispersed nanoparticles was obtained with 4 at.% μDiamond for posterior mixture with microdiamond and subsequent consolidation. Preliminary consolidation by hot extrusion of a mixture of pure copper and μDiamond has been carried out to define optimal processing parameters. The materials produced were characterized by x-ray diffraction, scanning and transmission electron microscopy and microhardness measurements.

Phase transformations in cerium and thorium metals at ultra high pressures

International Nuclear Information System (INIS)

Vohra, Y.K.

1991-01-01

This paper reports on the role of pressure variable in phase transformation which has not been fully exploited in metallic elements and their alloys. The static compression of over 50% in volume can readily be obtained in most metals and this tremendous change in inter-atomic distances can lead to the formation of new exotic crystal structures. The pressure-induced electron transfer amongst existing electronic energy bands and the occupation of new bands are the driving forces in a rich variety of phase transformations. The modern high pressure diamond anvil cell techniques can produce calibrated static pressures of over 300 to 400 GPa range and this technology, when interfaced with the synchrotron radiation sources, can yield rapid structural information (1-3). These capabilities have given new impetus for investigation of phase transformations in metallic systems at extreme conditions of temperatures and pressures and in establishing phase boundaries at high pressures and high temperatures. Cerium (Ce) and thorium (Th) metals occupy special positions in the periodic table at the beginning of the 4-f lanthanide and 5-f, actinide series, respectively. Ce has one electron in the localized 4-f shell, apart from the three valence electrons. Th metal, on the other hand, has four valence electrons and an unoccupied 5-f band above the Fermi-energy at ambient conditions. In view of the unoccupied 5-f band, Th metal is normally regarded as a tetravalent transition metal like Ti, Zr, and Hf and its bonding and other electronic properties can be explained within the tetravalent transition metal framework. However, the application of ultra-high pressures causes the delocalization of the 4-f shell in Ce and it is believed that Ce above 0.8 GPa pressure is a 4-f band metal

Micro-texturing into DLC/diamond coated molds and dies via high density oxygen plasma etching

Directory of Open Access Journals (Sweden)

Yunata Ersyzario Edo

2015-01-01

Full Text Available Diamond-Like Carbon (DLC and Chemical Vapor Deposition (CVD-diamond films have been widely utilized not only as a hard protective coating for molds and dies but also as a functional substrate for bio-MEMS/NEMS. Micro-texturing into these hard coated molds and dies provides a productive tool to duplicate the original mother micro-patterns onto various work materials and to construct any tailored micro-textures for sensors and actuators. In the present paper, the high density oxygen plasma etching method is utilized to make micro-line and micro-groove patterns onto the DLC and diamond coatings. Our developing oxygen plasma etching system is introduced together with characterization on the plasma state during etching. In this quantitative plasma diagnosis, both the population of activated species and the electron and ion densities are identified through the emissive light spectroscopy and the Langmuir probe method. In addition, the on-line monitoring of the plasmas helps to describe the etching process. DLC coated WC (Co specimen is first employed to describe the etching mechanism by the present method. Chemical Vapor Deposition (CVD diamond coated WC (Co is also employed to demonstrate the reliable capacity of the present high density oxygen plasma etching. This oxygen plasma etching performance is discussed by comparison of the etching rates.

Diamond electrophoretic microchips-Joule heating effects

International Nuclear Information System (INIS)

Karczemska, Anna T.; Witkowski, Dariusz; Ralchenko, Victor; Bolshakov, Andrey; Sovyk, Dmitry; Lysko, Jan M.; Fijalkowski, Mateusz; Bodzenta, Jerzy; Hassard, John

2011-01-01

Microchip electrophoresis (MCE) has become a mature separation technique in the recent years. In the presented research, a polycrystalline diamond electrophoretic microchip was manufactured with a microwave plasma chemical vapour deposition (MPCVD) method. A replica technique (mould method) was used to manufacture microstructures in diamond. A numerical analysis with CoventorWare TM was used to compare thermal properties during chip electrophoresis of diamond and glass microchips of the same geometries. Temperature distributions in microchips were demonstrated. Thermal, electrical, optical, chemical and mechanical parameters of the polycrystalline diamond layers are advantageous over traditionally used materials for microfluidic devices. Especially, a very high thermal conductivity coefficient gives a possibility of very efficient dissipation of Joule heat from the diamond electrophoretic microchip. This enables manufacturing of a new generation of microdevices.

Diamond electrophoretic microchips-Joule heating effects

Energy Technology Data Exchange (ETDEWEB)

Karczemska, Anna T., E-mail: anna.karczemska@p.lodz.pl [Technical University of Lodz, Institute of Turbomachinery, 219/223 Wolczanska str., Lodz (Poland); Witkowski, Dariusz [Technical University of Lodz, Institute of Turbomachinery, 219/223 Wolczanska str., Lodz (Poland); Ralchenko, Victor, E-mail: ralchenko@nsc.gpi.ru [General Physics Institute, Russian Academy of Science, 38 Vavilov str., Moscow (Russian Federation); Bolshakov, Andrey; Sovyk, Dmitry [General Physics Institute, Russian Academy of Science, 38 Vavilov str., Moscow (Russian Federation); Lysko, Jan M., E-mail: jmlysko@ite.waw.pl [Institute of Electron Technology, Al. Lotnikow 32/46, 02-668 Warsaw (Poland); Fijalkowski, Mateusz, E-mail: petr.louda@vslib.cz [Technical University of Liberec, Faculty of Mechanical Engineering (Czech Republic); Bodzenta, Jerzy, E-mail: jerzy.bodzenta@polsl.pl [Silesian University of Technology, Institute of Physics, 2 Krzywoustego str., 44-100 Gliwice (Poland); Hassard, John, E-mail: j.hassard@imperial.ac.uk [Imperial College of Science, Technology and Medicine, London (United Kingdom)

2011-03-15

Microchip electrophoresis (MCE) has become a mature separation technique in the recent years. In the presented research, a polycrystalline diamond electrophoretic microchip was manufactured with a microwave plasma chemical vapour deposition (MPCVD) method. A replica technique (mould method) was used to manufacture microstructures in diamond. A numerical analysis with CoventorWare{sup TM} was used to compare thermal properties during chip electrophoresis of diamond and glass microchips of the same geometries. Temperature distributions in microchips were demonstrated. Thermal, electrical, optical, chemical and mechanical parameters of the polycrystalline diamond layers are advantageous over traditionally used materials for microfluidic devices. Especially, a very high thermal conductivity coefficient gives a possibility of very efficient dissipation of Joule heat from the diamond electrophoretic microchip. This enables manufacturing of a new generation of microdevices.

Optimizing biosensing properties on undecylenic Acid-functionalized diamond.

Science.gov (United States)

Zhong, Yu Lin; Chong, Kwok Feng; May, Paul W; Chen, Zhi-Kuan; Loh, Kian Ping

2007-05-08

The optimization of biosensing efficiency on a diamond platform depends on the successful coupling of biomolecules on the surface, and also on effective signal transduction in the biorecognition events. In terms of biofunctionalization of diamond surfaces, surface electrochemical studies of diamond modified with undecylenic acid (UA), with and without headgroup protection, were performed. The direct photochemical coupling method employing UA was found to impart a higher density of carboxylic acid groups on the diamond surface compared to that using trifluoroethyl undecenoate (TFEU) as the protecting group during the coupling process. Non-faradic impedimetric DNA sensing revealed that lightly doped diamond gives better signal transduction sensitivity compared to highly doped diamond.

Electrochemical applications of CVD diamond

International Nuclear Information System (INIS)

Pastor-Moreno, Gustavo

2002-01-01

reduction of this redox couple modifying completely the mechanism of its reduction process. Photoelectrochemical studies using 1,4-benzoquinone in aqueous solution suggest that oxygen terminated surface of diamond is under the influence of the boron elemental states originated during the growing process. Diamond used as a heat sink allows developing a couple of new techniques to perform impedance and ac voltammetry measurements. These techniques do not depend on electrical components giving the possibility of high frequency studies without disruption from the instruments. These studies are just a grain in the dessert, further studies will be required to characterise this amazing electrode material. (author)

Towards Fast Reverse Time Migration Kernels using Multi-threaded Wavefront Diamond Tiling

KAUST Repository

Malas, T.

2015-09-13

Today’s high-end multicore systems are characterized by a deep memory hierarchy, i.e., several levels of local and shared caches, with limited size and bandwidth per core. The ever-increasing gap between the processor and memory speed will further exacerbate the problem and has lead the scientific community to revisit numerical software implementations to better suit the underlying memory subsystem for performance (data reuse) as well as energy efficiency (data locality). The authors propose a novel multi-threaded wavefront diamond blocking (MWD) implementation in the context of stencil computations, which represents the core operation for seismic imaging in oil industry. The stencil diamond formulation introduces temporal blocking for high data reuse in the upper cache levels. The wavefront optimization technique ensures data locality by allowing multiple threads to share common adjacent point stencil. Therefore, MWD is able to take up the aforementioned challenges by alleviating the cache size limitation and releasing pressure from the memory bandwidth. Performance comparisons are shown against the optimized 25-point stencil standard seismic imaging scheme using spatial and temporal blocking and demonstrate the effectiveness of MWD.

Development of high temperature, radiation hard detectors based on diamond

Energy Technology Data Exchange (ETDEWEB)

Metcalfe, Alex, E-mail: Alex.Metcalfe@brunel.ac.uk [Wolfson Centre for Materials Processing, Brunel University London, Uxbridge UB8 3PH (United Kingdom); Fern, George R. [Wolfson Centre for Materials Processing, Brunel University London, Uxbridge UB8 3PH (United Kingdom); Hobson, Peter R. [Centre for Sensors & Instrumentation, College of Engineering, Design and Physical Sciences, Brunel University London, Uxbridge UB8 3PH (United Kingdom); Ireland, Terry; Salimian, Ali; Silver, Jack [Wolfson Centre for Materials Processing, Brunel University London, Uxbridge UB8 3PH (United Kingdom); Smith, David R. [Centre for Sensors & Instrumentation, College of Engineering, Design and Physical Sciences, Brunel University London, Uxbridge UB8 3PH (United Kingdom); Lefeuvre, Gwenaelle [Micron Semiconductor Ltd., Lancing BN15 8 SJ (United Kingdom); Saenger, Richard [Schlumberger Limited, 91240 Clamart (France)

2017-02-11

Single crystal CVD diamond has many desirable properties compared to current, well developed, detector materials; exceptional radiation, chemical and physical hardness, chemical inertness, low Z (close to human tissue, good for dosimetry), wide bandgap and an intrinsic pathway to fast neutron detection through the {sup 12}C(n,α){sup 9}Be reaction. However effective exploitation of these properties requires development of a suitable metallisation scheme to give stable contacts for high temperature applications. To best utilise available processing techniques to optimise sensor response through geometry and conversion media configurations, a reliable model is required. This must assess the performance in terms of spectral response and overall efficiency as a function of detector and converter geometry. The same is also required for proper interpretation of experimental data. Sensors have been fabricated with varying metallisation schemes indented to permit high temperature operation; Present test results indicate that viable fabrication schemes for high temperature contacts have been developed and present modelling results, supported by preliminary data from partners indicate simulations provide a useful representation of response. - Highlights: • Radiation sensors using diamond as the sensitive volume have been constructed. • Functionality of these sensors with minimal degradation has been confirmed at 100 °C. • Sensitisation to thermal neutrons by addition of conversion layers has been modelled. • Modelling suggests 4× efficiency improvements from 3d converter-substrate interfaces.

Diamond identification

International Nuclear Information System (INIS)

Lang, A.R.

1979-01-01

Methods of producing sets of records of the internal defects of diamonds as a means of identification of the gems by x-ray topography are described. To obtain the records one can either use (a) monochromatic x-radiation reflected at the Bragg angle from crystallographically equivalent planes of the diamond lattice structure, Bragg reflections from each such plane being recorded from a number of directions of view, or (b) white x-radiation incident upon the diamond in directions having a constant angular relationship to each equivalent axis of symmetry of the diamond lattice structure, Bragg reflections being recorded for each direction of the incident x-radiation. By either method an overall point-to-point three dimensional representation of the diamond is produced. (U.K.)

14 CFR 23.253 - High speed characteristics.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false High speed characteristics. 23.253 Section... Requirements § 23.253 High speed characteristics. If a maximum operating speed VMO/MMO is established under § 23.1505(c), the following speed increase and recovery characteristics must be met: (a) Operating...

Impingement of water droplets on wedges and diamond airfoils at supersonic speeds

Science.gov (United States)

Serafini, John S

1953-01-01

An analytical solution has been obtained for the equations of motion of water droplets impinging on a wedge in a two-dimensional supersonic flow field with a shock wave attached to the wedge. The closed-form solution yields analytical expressions for the equation of the droplet trajectory, the local rate of impingement and the impingement velocity at any point on the wedge surface, and the total rate of impingement. The analytical expressions are utilized to determine the impingement on the forward surfaces of diamond airfoils in supersonic flow fields with attached shock waves. The results presented include the following conditions: droplet diameters from 2 to 100 microns, pressure altitudes from sea level to 30,000 feet, free-stream static temperatures from 420 degrees to 460 degrees R. Also, free-stream Mach numbers from 1.1 to 2.0, semi-apex angles for the wedge from 1.14 degrees to 7.97 degrees, thickness-to-chord ratios for the diamond airfoil from 0.02 to 0.14, chord lengths from 1 to 20 feet, and angles of attack from zero to the inverse tangent of the airfoil thickness-to-chord ratio.

Diamond exploration and mantle structure imaging using PIXE microanalysis

Energy Technology Data Exchange (ETDEWEB)

Ryan, C G; Griffin, W L; Win, T T [Commonwealth Scientific and Industrial Research Organisation (CSIRO), North Ryde, NSW (Australia). Div. of Exploration Geoscience

1997-12-31

Geochemical methods of diamond exploration rely on recognizing indicator minerals that formed in the earth`s upper mantle, within the diamond stability field, and were entrained in rapidly rising volatile-rich magmas and emplaced in or on the crust. Diamond is only stable at high pressure. Therefore, diamond exploration commonly targets prospects containing high pressure minerals, such as low-Ca, high-Cr (`G10`) garnets and high-Cr chromites, similar to inclusions in diamonds. However, this procedure can be ambiguous; some barren pipes contain abundant `G10` garnets. while such garnets are extremely rare in the Argyle pipe, the world`s largest diamond producer. Similarly, high-Cr chromites are shed by a wide variety of barren rock types. PIXE microanalysis of trace elements in concentrate garnets and chromites from kimberlites and other volcanic rocks helps to remove the ambiguities by pinning down the source temperature (T), pressure (P) and local (paleo)geotherm (P-T relation), which permits the rich store of trace element information in these minerals, reflecting rock chemistry and metasomatic processes, to be placed in a stratigraphic context. 11 refs., 4 figs.

Diamond exploration and mantle structure imaging using PIXE microanalysis

Energy Technology Data Exchange (ETDEWEB)

Ryan, C.G.; Griffin, W.L.; Win, T.T. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), North Ryde, NSW (Australia). Div. of Exploration Geoscience

1996-12-31

Geochemical methods of diamond exploration rely on recognizing indicator minerals that formed in the earth`s upper mantle, within the diamond stability field, and were entrained in rapidly rising volatile-rich magmas and emplaced in or on the crust. Diamond is only stable at high pressure. Therefore, diamond exploration commonly targets prospects containing high pressure minerals, such as low-Ca, high-Cr (`G10`) garnets and high-Cr chromites, similar to inclusions in diamonds. However, this procedure can be ambiguous; some barren pipes contain abundant `G10` garnets. while such garnets are extremely rare in the Argyle pipe, the world`s largest diamond producer. Similarly, high-Cr chromites are shed by a wide variety of barren rock types. PIXE microanalysis of trace elements in concentrate garnets and chromites from kimberlites and other volcanic rocks helps to remove the ambiguities by pinning down the source temperature (T), pressure (P) and local (paleo)geotherm (P-T relation), which permits the rich store of trace element information in these minerals, reflecting rock chemistry and metasomatic processes, to be placed in a stratigraphic context. 11 refs., 4 figs.

High-speed particle tracking in microscopy using SPAD image sensors

Science.gov (United States)

Gyongy, Istvan; Davies, Amy; Miguelez Crespo, Allende; Green, Andrew; Dutton, Neale A. W.; Duncan, Rory R.; Rickman, Colin; Henderson, Robert K.; Dalgarno, Paul A.

2018-02-01

Single photon avalanche diodes (SPADs) are used in a wide range of applications, from fluorescence lifetime imaging microscopy (FLIM) to time-of-flight (ToF) 3D imaging. SPAD arrays are becoming increasingly established, combining the unique properties of SPADs with widefield camera configurations. Traditionally, the photosensitive area (fill factor) of SPAD arrays has been limited by the in-pixel digital electronics. However, recent designs have demonstrated that by replacing the complex digital pixel logic with simple binary pixels and external frame summation, the fill factor can be increased considerably. A significant advantage of such binary SPAD arrays is the high frame rates offered by the sensors (>100kFPS), which opens up new possibilities for capturing ultra-fast temporal dynamics in, for example, life science cellular imaging. In this work we consider the use of novel binary SPAD arrays in high-speed particle tracking in microscopy. We demonstrate the tracking of fluorescent microspheres undergoing Brownian motion, and in intra-cellular vesicle dynamics, at high frame rates. We thereby show how binary SPAD arrays can offer an important advance in live cell imaging in such fields as intercellular communication, cell trafficking and cell signaling.

Diamond Detector Technology: Status and Perspectives

CERN Document Server

Reichmann, M; Artuso, M; Bachmair, F; Bäni, L; Bartosik, M; Beacham, J; Beck, H; Bellini, V; Belyaev, V; Bentele, B; Berdermann, E; Bergonzo, P; Bes, A; Brom, J-M; Bruzzi, M; Cerv, M; Chiodini, G; Chren, D; Cindro, V; Claus, G; Collot, J; Cumalat, J; Dabrowski, A; D'Alessandro, R; Dauvergne, D; de Boer, W; Dorfer, C; Dünser, M; Eremin, V; Eusebi, R; Forcolin, G; Forneris, J; Frais-Kölbl, H; Gallin-Martel, L; Gallin-Martel, M L; Gan, K K; Gastal, M; Giroletti, C; Goffe, M; Goldstein, J; Golubev, A; Gorišek, A; Grigoriev, E; Grosse-Knetter, J; Grummer, A; Gui, B; Guthoff, M; Haughton, I; Hiti, B; Hits, D; Hoeferkamp, M; Hofmann, T; Hosslet, J; Hostachy, J-Y; Hügging, F; Hutton, C; Jansen, H; Janssen, J; Kagan, H; Kanxheri, K; Kasieczka, G; Kass, R; Kassel, F; Kis, M; Konovalov, V; Kramberger, G; Kuleshov, S; Lacoste, A; Lagomarsino, S; Lo Giudice, A; Lukosi, E; Maazouzi, C; Mandic, I; Mathieu, C; Menichelli, M; Mikuž, M; Morozzi, A; Moss, J; Mountain, R; Murphy, S; Muškinja, M; Oh, A; Oliviero, P; Passeri, D; Pernegger, H; Perrino, R; Picollo, F; Pomorski, M; Potenza, R; Quadt, A; Re, A; Riley, G; Roe, S; Sanz-Becerra, D A; Scaringella, M; Schaefer, D; Schmidt, C J; Schnetzer, S; Sciortino, S; Scorzoni, A; Seidel, S; Servoli, L; Smith, S; Sopko, B; Sopko, V; Spagnolo, S; Spanier, S; Stenson, K; Stone, R; Sutera, C; Tannenwald, B; Taylor, A; Traeger, M; Tromson, D; Trischuk, W; Tuve, C; Uplegger, L; Velthuis, J; Venturi, N; Vittone, E; Wagner, S; Wallny, R; Wang, J C; Weingarten, J; Weiss, C; Wengler, T; Wermes, N; Yamouni, M; Zavrtanik, M

2018-01-01

The planned upgrade of the LHC to the High-Luminosity-LHC will push the luminosity limits above the original design values. Since the current detectors will not be able to cope with this environment ATLAS and CMS are doing research to find more radiation tolerant technologies for their innermost tracking layers. Chemical Vapour Deposition (CVD) diamond is an excellent candidate for this purpose. Detectors out of this material are already established in the highest irradiation regimes for the beam condition monitors at LHC. The RD42 collaboration is leading an effort to use CVD diamonds also as sensor material for the future tracking detectors. The signal behaviour of highly irradiated diamonds is presented as well as the recent study of the signal dependence on incident particle flux. There is also a recent development towards 3D detectors and especially 3D detectors with a pixel readout based on diamond sensors.

Extreme ultra-violet movie camera for imaging microsecond time scale magnetic reconnection

International Nuclear Information System (INIS)

Chai, Kil-Byoung; Bellan, Paul M.

2013-01-01

An ultra-fast extreme ultra-violet (EUV) movie camera has been developed for imaging magnetic reconnection in the Caltech spheromak/astrophysical jet experiment. The camera consists of a broadband Mo:Si multilayer mirror, a fast decaying YAG:Ce scintillator, a visible light block, and a high-speed visible light CCD camera. The camera can capture EUV images as fast as 3.3 × 10 6 frames per second with 0.5 cm spatial resolution. The spectral range is from 20 eV to 60 eV. EUV images reveal strong, transient, highly localized bursts of EUV radiation when magnetic reconnection occurs

Extreme ultra-violet movie camera for imaging microsecond time scale magnetic reconnection

Energy Technology Data Exchange (ETDEWEB)

Chai, Kil-Byoung; Bellan, Paul M. [Applied Physics, Caltech, 1200 E. California Boulevard, Pasadena, California 91125 (United States)

2013-12-15

An ultra-fast extreme ultra-violet (EUV) movie camera has been developed for imaging magnetic reconnection in the Caltech spheromak/astrophysical jet experiment. The camera consists of a broadband Mo:Si multilayer mirror, a fast decaying YAG:Ce scintillator, a visible light block, and a high-speed visible light CCD camera. The camera can capture EUV images as fast as 3.3 × 10{sup 6} frames per second with 0.5 cm spatial resolution. The spectral range is from 20 eV to 60 eV. EUV images reveal strong, transient, highly localized bursts of EUV radiation when magnetic reconnection occurs.

Proton Irradiation of CVD Diamond Detectors for High Luminosity Experiments at the LHC

CERN Document Server

Meier, D; Bauer, C; Berdermann, E; Bergonzo, P; Bogani, F; Borchi, E; Bruzzi, Mara; Colledani, C; Conway, J; Dabrowski, W; Delpierre, P A; Deneuville, A; Dulinski, W; van Eijk, B; Fallou, A; Foulon, F; Friedl, M; Gan, K K; Gheeraert, E; Grigoriev, E A; Hallewell, G D; Hall-Wilton, R; Han, S; Hartjes, F G; Hrubec, Josef; Husson, D; Jany, C; Kagan, H; Kania, D R; Kaplon, J; Kass, R; Knöpfle, K T; Krammer, Manfred; Manfredi, P F; Marshall, R D; Mishina, M; Le Normand, F; Pan, L S; Palmieri, V G; Pernegger, H; Pernicka, Manfred; Peitz, A; Pirollo, S; Pretzl, Klaus P; Re, V; Riester, J L; Roe, S; Roff, D G; Rudge, A; Schnetzer, S R; Sciortino, S; Speziali, V; Stelzer, H; Stone, R; Tapper, R J; Tesarek, R J; Thomson, G B; Trawick, M L; Trischuk, W; Turchetta, R; Walsh, A M; Wedenig, R; Weilhammer, Peter; Ziock, H J; Zöller, M

1999-01-01

CVD diamond shows promising properties for use as a position sensitive detector for experiments in the highest radiation areas at the Large Hadron Collider. In order to study the radiation hardn ess of diamond we exposed CVD diamond detector samples to 24~GeV/$c$ and 500~MeV protons up to a fluence of $5\\times 10^{15}~p/{\\rm cm^2}$. We measured the charge collection distance, the ave rage distance electron hole pairs move apart in an external electric field, and leakage currents before, during, and after irradiation. The charge collection distance remains unchanged up to $1\\ times 10^{15}~p/{\\rm cm^2}$ and decreases by $\\approx$40~\\% at $5\\times 10^{15}~p/{\\rm cm^2}$. Leakage currents of diamond samples were below 1~pA before and after irradiation. The particle indu ced currents during irradiation correlate well with the proton flux. In contrast to diamond, a silicon diode, which was irradiated for comparison, shows the known large increase in leakage curren t. We conclude that CVD diamond detectors are radia...

Polycrystalline diamond detectors with three-dimensional electrodes

Energy Technology Data Exchange (ETDEWEB)

Lagomarsino, S., E-mail: lagomarsino@fi.infn.it [University of Florence, Department of Physics, Via Sansone 1, 50019 Sesto Fiorentino (Italy); INFN Firenze, Via B. Rossi 1, 50019 Sesto Fiorentino (Italy); Bellini, M. [INO-CNR Firenze, Largo E. Fermi 6, 50125 Firenze (Italy); Brianzi, M. [INFN Firenze, Via B. Rossi 1, 50019 Sesto Fiorentino (Italy); Carzino, R. [Smart Materials-Nanophysics, Istituto Italiano di Tecnologia, Genova, Via Morego 30, 16163 Genova (Italy); Cindro, V. [Joseph Stefan Institute, Jamova Cesta 39, 1000 Ljubljana (Slovenia); Corsi, C. [University of Florence, Department of Physics, Via Sansone 1, 50019 Sesto Fiorentino (Italy); LENS Firenze, Via N. Carrara 1, 50019 Sesto Fiorentino (Italy); Morozzi, A.; Passeri, D. [INFN Perugia, Perugia (Italy); Università degli Studi di Perugia, Dipartimento di Ingegneria, via G. Duranti 93, 06125 Perugia (Italy); Sciortino, S. [University of Florence, Department of Physics, Via Sansone 1, 50019 Sesto Fiorentino (Italy); INFN Firenze, Via B. Rossi 1, 50019 Sesto Fiorentino (Italy); Servoli, L. [INFN Perugia, Perugia (Italy)

2015-10-01

The three-dimensional concept in diamond detectors has been applied, so far, to high quality single-crystal material, in order to test this technology in the best available conditions. However, its application to polycrystalline chemical vapor deposited diamond could be desirable for two reasons: first, the short inter-electrode distance of three-dimensional detectors should improve the intrinsically lower collection efficiency of polycrystalline diamond, and second, at high levels of radiation damage the performances of the poly-crystal material are not expected to be much lower than those of the single crystal one. We report on the fabrication and test of three-dimensional polycrystalline diamond detectors with several inter-electrode distances, and we demonstrate that their collection efficiency is equal or higher than that obtained with conventional planar detectors fabricated with the same material. - Highlights: • Pulsed laser fabrication of polycristalline diamond detectors with 3D electrodes. • Measurement of the charge collection efficiency (CCE) under beta irradiation. • Comparation between the CCE of 3D and conventional planar diamond sensors. • A rationale for the behavior of three-dimensional and planar sensors is given.

Study on the Effect of Diamond Grain Size on Wear of Polycrystalline Diamond Compact Cutter

Science.gov (United States)

Abdul-Rani, A. M.; Che Sidid, Adib Akmal Bin; Adzis, Azri Hamim Ab

2018-03-01

Drilling operation is one of the most crucial step in oil and gas industry as it proves the availability of oil and gas under the ground. Polycrystalline Diamond Compact (PDC) bit is a type of bit which is gaining popularity due to its high Rate of Penetration (ROP). However, PDC bit can easily wear off especially when drilling hard rock. The purpose of this study is to identify the relationship between the grain sizes of the diamond and wear rate of the PDC cutter using simulation-based study with FEA software (ABAQUS). The wear rates of a PDC cutter with a different diamond grain sizes were calculated from simulated cuttings of cutters against granite. The result of this study shows that the smaller the diamond grain size, the higher the wear resistivity of PDC cutter.

Towards High Density 3-D Memory in Diamond

Science.gov (United States)

Henshaw, Jacob; Dhomkar, Siddharth; Meriles, Carlos; Jayakumar, Harishankar

The nitrogen-vacancy (NV) center in diamond is presently the focus of widespread attention for applications ranging from quantum information processing to nanoscale metrology. Of great utility is the ability to optically initialize the NV charge state, which has an immediate impact on the center's light emission properties. Here, we use two-color microscopy in NV-rich, type-1b diamond to demonstrate fluorescence-encoded long-term storage of classical information. As a proof of principle, we write, reset, and rewrite various patterns with 2-D binary bit density comparable to present DVD-ROM technology. The strong fluorescence signal originating from the diffraction-limited bit volume allows us to transition from binary to multi-valued encoding, which translates into a significant storage capacity boost. Finally, we show that our technique preserves information written on different planes of the diamond crystal and thus serves as a platform for three-dimensional storage. Substantial enhancement in the bit density could be achieved with the aid of super resolution microscopy techniques already employed to discriminate between NVs with sub-diffraction, nanometer accuracy, a regime where the storage capacity could exceed 1017 bytes/cm3 We acknowledge support from the National Science Foundation through Grant NSF-1314205.

An ultra-high-speed direct digital frequency synthesizer implemented in GaAs HBT technology

International Nuclear Information System (INIS)

Chen Gaopeng; Wu Danyu; Jin Zhi; Liu Xinyu

2010-01-01

This paper presents a 10-GHz 8-bit direct digital synthesizer (DDS) microwave monolithic integrated circuit implemented in 1 μm GaAs HBT technology. The DDS takes a double-edge-trigger (DET) 8-stage pipeline accumulator with sine-weighted DAC-based ROM-less architecture, which can maximize the utilization ratio of the GaAs HBT's high-speed potential. With an output frequency up to 5 GHz, the DDS gives an average spurious free dynamic range of 23.24 dBc through the first Nyquist band, and consumes 2.4 W of DC power from a single -4.6 V DC supply. Using 1651 GaAs HBT transistors, the total area of the DDS chip is 2.4 x 2.0 mm 2 . (semiconductor integrated circuits)

Ultra high-energy cosmic ray composition

International Nuclear Information System (INIS)

Longley, N.P.

1993-01-01

The Soudan 2 surface-underground cosmic ray experiment can simultaneously measure surface shower size, underground muon multiplicity, and underground muon separation for ultra high energy cosmic ray showers. These measurements are sensitive to the primary composition. Analysis for energies from 10 1 to 10 4 TeV favors a light flux consisting of predominantly H and He nuclei

Connections in Precast Buildings using Ultra High-Strength Fibre Reinforced Concrete

DEFF Research Database (Denmark)

Hansen, Lars Pilegaard

1995-01-01

Ultra high-strength concrete adds new dimensions to the design of concrete structures. It is a brittle material but introducing fibres into the matrix changes the material into a highly ductile material. Furthermore, the fibre reinforcement increases the anchorage of traditional reinforcement bar...... and the fire resistance. Such a fibre reinforced ultra high-strength material has been used to develop a simple joint solution between slab elements in a column - slab building system....

Application of CVD diamond film for radiation detection

International Nuclear Information System (INIS)

Zhou Haiyang; Zhu Xiaodong; Zhan Rujuan

2005-01-01

With the development of diamond synthesis at low pressure, the CVD diamond properties including electronic characteristics have improved continuously. Now the fabrication of electronic devices based on the CVD diamond has been one of hot research subjects in this field. Due to many unique advantages, such as high signal-noise ratio, fast time response, and normal output in extremely harsh surrounding, the CVD diamond radiation detector has attracted more and more interest. In this paper, we have reviewed the development and status of the CVD diamond radiation detector. The prospect of this detector is described. (authors)

A novel diamond-based beam position monitoring system for the High Radiation to Materials facility at CERN SPS

CERN Document Server

AUTHOR|(CDS)2092886; Höglund, Carina

The High Radiation to Materials facility employs a high intensity pulsed beam imposing several challenges on the beam position monitors. Diamond has been shown to be a resilient material with its radiation hardness and mechanical strength, while it is also simple due to its wide bandgap removing the need for doping. A new type of diamond based beam position monitor has been constructed, which includes a hole in the center of the diamond where the majority of the beam is intended to pass through. This increases the longevity of the detectors as well as allowing them to be used for high intensity beams. The purpose of this thesis is to evaluate the performance of the detectors in the High Radiation to Materials facility for various beam parameters, involving differences in position, size, bunch intensity and bunch number. A prestudy consisting of calibration of the detectors using single incident particles is also presented. The detectors are shown to work as intended after a recalibration of the algorithm, alb...

High-Speed Photography

International Nuclear Information System (INIS)

Paisley, D.L.; Schelev, M.Y.

1998-01-01

The applications of high-speed photography to a diverse set of subjects including inertial confinement fusion, laser surgical procedures, communications, automotive airbags, lightning etc. are briefly discussed. (AIP) copyright 1998 Society of Photo-Optical Instrumentation Engineers

Comparison of Corneal Deformation Parameters in Keratoconic and Normal Eyes Using a Non-contact Tonometer With a Dynamic Ultra-High-Speed Scheimpflug Camera.

Science.gov (United States)

Mercer, Ryan N; Waring, George O; Roberts, Cynthia J; Jhanji, Vishal; Wang, Yumeng; Filho, Joao S; Hemings, Richard A; Rocha, Karolinne M

2017-09-01

To evaluate and compare biomechanical properties in normal and keratoconic eyes using a dynamic ultra-high-speed Scheimpflug camera equipped with a non-contact tonometer (Corvis ST; Oculus Optikgeräte GmbH, Wetzlar, Germany). This retrospective study evaluated 89 eyes (47 normal, 42 keratoconic) and a validation arm of 72 eyes (33 normal, 39 keratoconic) using the Corvis ST. A diagnosis of keratoconus was established by clinical findings confirmed by topography and tomography. Dynamic corneal response parameters collected by the Corvis ST (A1 velocity, deformation amplitude [DA], DA Ratio Max 1mm, and Max Inverse Radius) and a stiffness parameter at first applanation (SP-A1) were incorporated into a novel logistic regression equation (DCR index). Area under the receiver operating curve (AUC) was used to assess the sensitivity and specificity of the DCR index. DA, DA Ratio Max 1mm, Max Inverse Radius, and SP-A1 were each found to be statistically significantly different between normal and keratoconic eyes (Mann-Whitney test [independent samples]; P = .0077, < .0001, < .0001, and < .0001, respectively; significance level: P < .05). DCR index demonstrated high sensitivity, specificity, and overall correct detection rate (92.9%, 95.7%, and 94.4%, respectively; AUC = 98.5). The sensitivity and overall correct detection rate improved when eyes with Topographical Keratoconus Classification grades (TKC) greater than 0 were reevaluated (from 92.9% to 96.6% and from 94.4% to 96.1%, respectively). Combining multiple biomechanical parameters (A1 velocity, DA, DA Ratio Max 1mm, Max Inverse Radius, and SP-A1) into a logistic regression equation allows for high sensitivity and specificity for distinguishing keratoconic from normal eyes. [J Refract Surg. 2017;33(9):625-631.]. Copyright 2017, SLACK Incorporated.

Ohmic contacts to semiconducting diamond

Science.gov (United States)

Zeidler, James R.; Taylor, M. J.; Zeisse, Carl R.; Hewett, C. A.; Delahoussaye, Paul R.

1990-10-01

Work was carried out to improve the electron beam evaporation system in order to achieve better deposited films. The basic system is an ion pumped vacuum chamber, with a three-hearth, single-gun e-beam evaporator. Four improvements were made to the system. The system was thoroughly cleaned and new ion pump elements, an e-gun beam adjust unit, and a more accurate crystal monitor were installed. The system now has a base pressure of 3 X 10(exp -9) Torr, and can easily deposit high-melting-temperature metals such as Ta with an accurately controlled thickness. Improved shadow masks were also fabricated for better alignment and control of corner contacts for electrical transport measurements. Appendices include: A Thermally Activated Solid State Reaction Process for Fabricating Ohmic Contacts to Semiconducting Diamond; Tantalum Ohmic Contacts to Diamond by a Solid State Reaction Process; Metallization of Semiconducting Diamond: Mo, Mo/Au, and Mo/Ni/Au; Specific Contact Resistance Measurements of Ohmic Contracts to Diamond; and Electrical Activation of Boron Implanted into Diamond.

Ultra high performance concrete made with rice husk ash for reduced autogenous shrinkage

NARCIS (Netherlands)

Van Breugel, K.; Van Tuan, N.

2014-01-01

Ultra High Strength Concrete (UHPC) is generally made with low w/c mixtures and by adding silica fume. Low w/c mixtures, however, exhibit high autogenous shrinkage, while a high amount of silica fume increases the price of these mixtures. For designing ultra high strength mixtures with low

Very High Load Capacity Air Bearing Spindle for Large Diamond Turning Machines, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Diamond turning is able to produce highly aspheric visible quality optics which can be easily aligned. Very large optical systems such as OWL and EUSO are impossible...

CVD diamond deposition onto dental burs

International Nuclear Information System (INIS)

Ali, N.; Sein, H.

2001-01-01

A hot-filament chemical vapor deposition (HFCVD) system has been modified to enable non-planar substrates, such as metallic wires and dental burs, to be uniformly coated with thin polycrystalline diamond films. Initially, diamond deposition was carried out on titanium and tantalum wires in order to test and optimize the system. High growth rates of the order of approx. 8 /hr were obtained when depositing diamond on titanium wires using the vertical filament arrangement. However, lower growth rates of the order of 4-5meu m/hr were obtained with diamond deposition on tantalum wires. To extend the work towards a practical biomedical application tungsten carbide dental burs were coated with diamond films. The as-grown films were found to be polycrystalline and uniform over the cutting tip. Finally, the costs relating to diamond CVD onto dental burs have been presented in this paper. The costs relating to coating different number of burs at a time and the effect of film thickness on costs have been included in this investigation. (author)

Influence of high volumes of ultra-fine additions on self-compacting concrete[ACI SP-239

Energy Technology Data Exchange (ETDEWEB)

Cioffi, R. [Naples Univ., Naples (Italy). Faculty of Engineering; Colangelo, F. [Naples Univ., Naples (Italy). Dept. of Technologies; Caputo, D.; Liguori, B. [Naples Univ., Naples (Italy). Dept. of Materials and Production Engineering

2006-07-01

The addition of fine minerals can reduce water demand and increase the slump characteristics of concrete. This paper examined the influence of high volumes of ultra-fine fly ash, raw fly ash, silica fume and natural zeolites on the properties of self-compacting concrete (SCC). Three samples of SCC were prepared using various mineral additions to determine normal slump and J-ring slump flows of fresh concrete as well as the compressive strength and elastic modulus properties of hardened concrete. Cement and crushed limestone natural aggregates were used. The fly ash, silica fume and natural zeolites were subjected to wet high energy milling. The rotating speed, milling time, water-to-solid ratio, and size of milling media were optimized to obtain powders with varying qualities. Results of the study showed that values for the normal slump flow ranged between 604 and 785 mm, while the differences with the J-ring slump flow were less than 30 mm. The samples were then tested to evaluate the mechanical properties of the hardened concrete after 7 and 28 curing days. The modulus of elasticity and compressive strength showed improvements in the concretes containing the ultra-fine fly ash. No segregation phenomena were observed in the case of the cylindrical column specimens. It was concluded that all the specimens provided environmentally sustainable, high workability concretes which can be successfully prepared with the addition of high volumes of minerals. 17 refs., 5 tabs., 6 figs.

Encapsulation of electroless copper patterns into diamond films

Energy Technology Data Exchange (ETDEWEB)

Pimenov, S.M.; Shafeev, G.A.; Lavrischev, S.V. [General Physics Institute, Moscow (Russian Federation)] [and others

1995-12-31

The results are reported on encapsulating copper lines into diamond films grown by a DC plasma CVD. The process includes the steps of (i) laser activation of diamond for electroless metal plating, (ii) electroless copper deposition selectively onto the activated surface regions, and (iii) diamond regrowth on the Cu-patterned diamond films. The composition and electrical properties of the encapsulated copper lines were examined, revealing high purity and low electrical resistivity of the encapsulated electroless copper.

Drilling of optical glass with electroplated diamond tools

Science.gov (United States)

Wang, A. J.; Luan, C. G.; Yu, A. B.

2010-10-01

K9 optical glass drilling experiments were carried out. Bright nickel electroplated diamond tools with small slots and under heat treatment in different temperature were fabricated. Scan electro microscope was applied to analyze the wear of electroplated diamond tool. The material removal rate and grinding ratio were calculated. Machining quality was observed. Bond coating hardness was measured. The experimental results show that coolant is needed for the drilling processes of optical glasses. Heat treatment temperature of diamond tool has influence on wearability of diamond tool and grinding ratio. There were two wear types of electroplated diamond tool, diamond grit wear and bond wear. With the machining processes, wear of diamond grits included fracture, blunt and pull-out, and electroplated bond was gradually worn out. High material removal rates could be obtained by using diamond tool with suitable slot numbers. Bright nickel coating bond presents smallest grains and has better mechanical properties. Bright nickel electroplated diamond tool with slot structure and heat treatment under 200°C was suitable for optical glass drilling.

Ultra-high field MRI: Advancing systems neuroscience towards mesoscopic human brain function

NARCIS (Netherlands)

Dumoulin, Serge O; Fracasso, A.; Van der Zwaag, W.; Siero, Jeroen C W; Petridou, Natalia

2018-01-01

Human MRI scanners at ultra-high magnetic field strengths of 7 T and higher are increasingly available to the neuroscience community. A key advantage brought by ultra-high field MRI is the possibility to increase the spatial resolution at which data is acquired, with little reduction in image

Ultrahigh-speed X-ray imaging of hypervelocity projectiles

Science.gov (United States)

Miller, Stuart; Singh, Bipin; Cool, Steven; Entine, Gerald; Campbell, Larry; Bishel, Ron; Rushing, Rick; Nagarkar, Vivek V.

2011-08-01

High-speed X-ray imaging is an extremely important modality for healthcare, industrial, military and research applications such as medical computed tomography, non-destructive testing, imaging in-flight projectiles, characterizing exploding ordnance, and analyzing ballistic impacts. We report on the development of a modular, ultrahigh-speed, high-resolution digital X-ray imaging system with large active imaging area and microsecond time resolution, capable of acquiring at a rate of up to 150,000 frames per second. The system is based on a high-resolution, high-efficiency, and fast-decay scintillator screen optically coupled to an ultra-fast image-intensified CCD camera designed for ballistic impact studies and hypervelocity projectile imaging. A specially designed multi-anode, high-fluence X-ray source with 50 ns pulse duration provides a sequence of blur-free images of hypervelocity projectiles traveling at speeds exceeding 8 km/s (18,000 miles/h). This paper will discuss the design, performance, and high frame rate imaging capability of the system.

High Thermal Conductivity NARloy-Z-Diamond Composite Liner for Advanced Rocket Engines

Science.gov (United States)

Bhat, Biliyar; Greene, Sandra

2015-01-01

NARloy-Z (Cu-3Ag-0.5Zr) alloy is state-of-the-art combustion chamber liner material used in liquid propulsion engines such as the RS-68 and RS-25. The performance of future liquid propulsion systems can be improved significantly by increasing the heat transfer through the combustion chamber liner. Prior work1 done at NASA Marshall Space Flight Center (MSFC) has shown that the thermal conductivity of NARloy-Z alloy can be improved significantly by embedding high thermal conductivity diamond particles in the alloy matrix to form NARloy-Z-diamond composite (fig. 1). NARloy-Z-diamond composite containing 40vol% diamond showed 69% higher thermal conductivity than NARloy-Z. It is 24% lighter than NARloy-Z and hence the density normalized thermal conductivity is 120% better. These attributes will improve the performance and life of the advanced rocket engines significantly. The research work consists of (a) developing design properties (thermal and mechanical) of NARloy-Z-D composite, (b) fabrication of net shape subscale combustion chamber liner, and (c) hot-fire testing of the liner to test performance. Initially, NARloy-Z-D composite slabs were made using the Field Assisted Sintering Technology (FAST) for the purpose of determining design properties. In the next step, a cylindrical shape was fabricated to demonstrate feasibility (fig. 3). The liner consists of six cylinders which are sintered separately and then stacked and diffusion bonded to make the liner (fig. 4). The liner will be heat treated, finish-machined, and assembled into a combustion chamber and hot-fire tested in the MSFC test facility (TF 115) to determine perform.

A Delay Time Measurement of ULTRAS (Ultra-high Temperature Ultrasonic Response Analysis System) for a High Temperature Experiment

International Nuclear Information System (INIS)

Koo, Kil Mo; Kim, Sang Baik

2010-01-01

The temperature measurement of very high temperature core melt is of importance in a high temperature as the molten pool experiment in which gap formation between core melt and the reactor lower head, and the effect of the gap on thermal behavior are to be measured. The existing temperature measurement techniques have some problems, which the thermocouple, one of the contact methods, is restricted to under 2000 .deg. C, and the infrared thermometry, one of the non-contact methods, is unable to measure an internal temperature and very sensitive to the interference from reacted gases. In order to solve these problems, the delay time technique of ultrasonic wavelets due to high temperature has two sorts of stage. As a first stage, a delay time measurement of ULTRAS (Ultra-high Temperature Ultrasonic Response Analysis System) is suggested. As a second stage, a molten material temperature was measured up to 2300 .deg. C. Also, the optimization design of the UTS (ultrasonic temperature sensor) with persistence at the high temperature was suggested in this paper. And the utilization of the theory suggested in this paper and the efficiency of the developed system are performed by special equipment and some experiments supported by KRISS (Korea Research Institute of Standard and Science)

SEAL FOR HIGH SPEED CENTRIFUGE

Science.gov (United States)

Skarstrom, C.W.

1957-12-17

A seal is described for a high speed centrifuge wherein the centrifugal force of rotation acts on the gasket to form a tight seal. The cylindrical rotating bowl of the centrifuge contains a closure member resting on a shoulder in the bowl wall having a lower surface containing bands of gasket material, parallel and adjacent to the cylinder wall. As the centrifuge speed increases, centrifugal force acts on the bands of gasket material forcing them in to a sealing contact against the cylinder wall. This arrangememt forms a simple and effective seal for high speed centrifuges, replacing more costly methods such as welding a closure in place.

Ultra-high throughput real-time instruments for capturing fast signals and rare events

Science.gov (United States)

Buckley, Brandon Walter

Wide-band signals play important roles in the most exciting areas of science, engineering, and medicine. To keep up with the demands of exploding internet traffic, modern data centers and communication networks are employing increasingly faster data rates. Wide-band techniques such as pulsed radar jamming and spread spectrum frequency hopping are used on the battlefield to wrestle control of the electromagnetic spectrum. Neurons communicate with each other using transient action potentials that last for only milliseconds at a time. And in the search for rare cells, biologists flow large populations of cells single file down microfluidic channels, interrogating them one-by-one, tens of thousands of times per second. Studying and enabling such high-speed phenomena pose enormous technical challenges. For one, parasitic capacitance inherent in analog electrical components limits their response time. Additionally, converting these fast analog signals to the digital domain requires enormous sampling speeds, which can lead to significant jitter and distortion. State-of-the-art imaging technologies, essential for studying biological dynamics and cells in flow, are limited in speed and sensitivity by finite charge transfer and read rates, and by the small numbers of photo-electrons accumulated in short integration times. And finally, ultra-high throughput real-time digital processing is required at the backend to analyze the streaming data. In this thesis, I discuss my work in developing real-time instruments, employing ultrafast optical techniques, which overcome some of these obstacles. In particular, I use broadband dispersive optics to slow down fast signals to speeds accessible to high-bit depth digitizers and signal processors. I also apply telecommunication multiplexing techniques to boost the speeds of confocal fluorescence microscopy. The photonic time stretcher (TiSER) uses dispersive Fourier transformation to slow down analog signals before digitization and

CVD diamond for nuclear detection applications

CERN Document Server

Bergonzo, P; Tromson, D; Mer, C; Guizard, B; Marshall, R D; Foulon, F

2002-01-01

Chemically vapour deposited (CVD) diamond is a remarkable material for the fabrication of radiation detectors. In fact, there exist several applications where other standard semiconductor detectors do not fulfil the specific requirements imposed by corrosive, hot and/or high radiation dose environments. The improvement of the electronic properties of CVD diamond has been under intensive investigations and led to the development of a few applications that are addressing specific industrial needs. Here, we report on CVD diamond-based detector developments and we describe how this material, even though of a polycrystalline nature, is readily of great interest for applications in the nuclear industry as well as for physics experiments. Improvements in the material synthesis as well as on device fabrication especially concern the synthesis of films that do not exhibit space charge build up effects which are often encountered in CVD diamond materials and that are highly detrimental for detection devices. On a pre-i...

Detection of diamonds

International Nuclear Information System (INIS)

Hansen, J.O.; Blondeel, E.J.G.; Taylor, G.T.

1991-01-01

Diamond particles are distinguished from non-diamond, associated particles on the basis of their higher refractive index. The particles are brought to a specific location, typically in a stream of water flowing full in a vertical duct, and a beam of collimated electromagnetic radiation is directed at them. An array of radiation detectors is provided to detect refracted and/or reflected radiation. The array is so configured that the responses of the detectors, considered collectively, will be indicative of the presence of a diamond when a diamond is in fact present. However, when a particle having a substantially lower refractive index is present, the responses of the detectors will not be so indicative. The diamond and non-diamond particles can subsequently be sorted from one another

Diamond thin films: giving biomedical applications a new shine.

Science.gov (United States)

Nistor, P A; May, P W

2017-09-01

Progress made in the last two decades in chemical vapour deposition technology has enabled the production of inexpensive, high-quality coatings made from diamond to become a scientific and commercial reality. Two properties of diamond make it a highly desirable candidate material for biomedical applications: first, it is bioinert, meaning that there is minimal immune response when diamond is implanted into the body, and second, its electrical conductivity can be altered in a controlled manner, from insulating to near-metallic. In vitro, diamond can be used as a substrate upon which a range of biological cells can be cultured. In vivo , diamond thin films have been proposed as coatings for implants and prostheses. Here, we review a large body of data regarding the use of diamond substrates for in vitro cell culture. We also detail more recent work exploring diamond-coated implants with the main targets being bone and neural tissue. We conclude that diamond emerges as one of the major new biomaterials of the twenty-first century that could shape the way medical treatment will be performed, especially when invasive procedures are required. © 2017 The Authors.

High-Speed Data Recorder for Space, Geodesy, and Other High-Speed Recording Applications

Science.gov (United States)

Taveniku, Mikael

2013-01-01

A high-speed data recorder and replay equipment has been developed for reliable high-data-rate recording to disk media. It solves problems with slow or faulty disks, multiple disk insertions, high-altitude operation, reliable performance using COTS hardware, and long-term maintenance and upgrade path challenges. The current generation data recor - ders used within the VLBI community are aging, special-purpose machines that are both slow (do not meet today's requirements) and are very expensive to maintain and operate. Furthermore, they are not easily upgraded to take advantage of commercial technology development, and are not scalable to multiple 10s of Gbit/s data rates required by new applications. The innovation provides a softwaredefined, high-speed data recorder that is scalable with technology advances in the commercial space. It maximally utilizes current technologies without being locked to a particular hardware platform. The innovation also provides a cost-effective way of streaming large amounts of data from sensors to disk, enabling many applications to store raw sensor data and perform post and signal processing offline. This recording system will be applicable to many applications needing realworld, high-speed data collection, including electronic warfare, softwaredefined radar, signal history storage of multispectral sensors, development of autonomous vehicles, and more.

Subsurface damage mechanism of high speed grinding process in single crystal silicon revealed by atomistic simulations

International Nuclear Information System (INIS)

Li, Jia; Fang, Qihong; Zhang, Liangchi; Liu, Youwen

2015-01-01

Highlights: • Molecular dynamic model of nanoscale high speed grinding of silicon workpiece has been established. • The effect of grinding speed on subsurface damage and grinding surface integrity by analyzing the chip, dislocation movement, and phase transformation during high speed grinding process are thoroughly investigated. • Subsurface damage is studied by the evolution of surface area at first time for more obvious observation on transition from ductile to brittle. • The hydrostatic stress and von Mises stress by the established analytical model are studied subsurface damage mechanism during nanoscale grinding. - Abstract: Three-dimensional molecular dynamics (MD) simulations are performed to investigate the nanoscale grinding process of single crystal silicon using diamond tool. The effect of grinding speed on subsurface damage and grinding surface integrity by analyzing the chip, dislocation movement, and phase transformation are studied. We also establish an analytical model to calculate several important stress fields including hydrostatic stress and von Mises stress for studying subsurface damage mechanism, and obtain the dislocation density on the grinding subsurface. The results show that a higher grinding velocity in machining brittle material silicon causes a larger chip and a higher temperature, and reduces subsurface damage. However, when grinding velocity is above 180 m s −1 , subsurface damage thickness slightly increases because a higher grinding speed leads to the increase in grinding force and temperature, which accelerate dislocation nucleation and motion. Subsurface damage is studied by the evolution of surface area at first time for more obvious observation on transition from ductile to brittle, that provides valuable reference for machining nanometer devices. The von Mises stress and the hydrostatic stress play an important role in the grinding process, and explain the subsurface damage though dislocation mechanism under high

Diamond based adsorbents and their application in chromatography.

Science.gov (United States)

Peristyy, Anton A; Fedyanina, Olga N; Paull, Brett; Nesterenko, Pavel N

2014-08-29

The idea of using diamond and diamond containing materials in separation sciences has attracted a strong interest in the past decade. The combination of a unique range of properties, such as chemical inertness, mechanical, thermal and hydrolytic stability, excellent thermal conductivity with minimal thermal expansion and intriguing adsorption properties makes diamond a promising material for use in various modes of chromatography. This review summarises the recent research on the preparation of diamond and diamond based stationary phases, their properties and chromatographic performance. Special attention is devoted to the dominant retention mechanisms evident for particular diamond containing phases, and their subsequent applicability to various modes of chromatography, including chromatography carried out under conditions of high temperature and pressure. Copyright © 2014 Elsevier B.V. All rights reserved.

Proton irradiation of CVD diamond detectors for high-luminosity experiments at the LHC

Science.gov (United States)

Meier, D.; Adam, W.; Bauer, C.; Berdermann, E.; Bergonzo, P.; Bogani, F.; Borchi, E.; Bruzzi, M.; Colledani, C.; Conway, J.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; van Eijk, B.; Fallou, A.; Foulon, F.; Friedl, M.; Jany, C.; Gan, K. K.; Gheeraert, E.; Grigoriev, E.; Hallewell, G.; Hall-Wilton, R.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Kass, R.; Knöpfle, K. T.; Krammer, M.; Manfredi, P. F.; Marshall, R. D.; Mishina, M.; Le Normand, F.; Pan, L. S.; Palmieri, V. G.; Pernegger, H.; Pernicka, M.; Peitz, A.; Pirollo, S.; Pretzl, K.; Re, V.; Riester, J. L.; Roe, S.; Roff, D.; Rudge, A.; Schnetzer, S.; Sciortino, S.; Speziali, V.; Stelzer, H.; Stone, R.; Tapper, R. J.; Tesarek, R.; Thomson, G. B.; Trawick, M.; Trischuk, W.; Turchetta, R.; Walsh, A. M.; Wedenig, R.; Weilhammer, P.; Ziock, H.; Zoeller, M.; RD42 Collaboration

1999-04-01

CVD diamond shows promising properties for use as a position-sensitive detector for experiments in the highest radiation areas at the Large Hadron Collider. In order to study the radiation hardness of diamond we exposed CVD diamond detector samples to 24 Gev/ c and 500 Mev protons up to a fluence of 5×10 15 p/cm 2. We measured the charge collection distance, the average distance electron-hole pairs move apart in an external electric field, and leakage currents before, during, and after irradiation. The charge collection distance remains unchanged up to 1×10 15 p/cm 2 and decreases by ≈40% at 5×10 15 p/cm 2. Leakage currents of diamond samples were below 1 pA before and after irradiation. The particle-induced currents during irradiation correlate well with the proton flux. In contrast to diamond, a silicon diode, which was irradiated for comparison, shows the known large increase in leakage current. We conclude that CVD diamond detectors are radiation hard to 24 GeV/ c and 500 MeV protons up to at least 1×10 15p/cm 2 without signal loss.

Proton irradiation of CVD diamond detectors for high-luminosity experiments at the LHC

International Nuclear Information System (INIS)

Meier, D.; Adam, W.; Bauer, C.; Berdermann, E.; Bergonzo, P.; Bogani, F.; Borchi, E.; Bruzzi, M.; Colledani, C.; Conway, J.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; Eijk, B. van; Fallou, A.; Foulon, F.; Friedl, M.; Jany, C.; Gan, K.K.; Gheeraert, E.; Grigoriev, E.; Hallewell, G.; Hall-Wilton, R.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Kass, R.; Knoepfle, K.T.; Krammer, M.; Manfredi, P.F.; Marshall, R.D.; Mishina, M.; Le Normand, F.; Pan, L.S.; Palmieri, V.G.; Pernegger, H.; Pernicka, M.; Peitz, A.; Pirollo, S.; Pretzl, K.; Re, V.; Riester, J.L.; Roe, S.; Roff, D.; Rudge, A.; Schnetzer, S.; Sciortino, S.; Speziali, V.; Stelzer, H.; Stone, R.; Tapper, R.J.; Tesarek, R.; Thomson, G.B.; Trawick, M.; Trischuk, W.; Turchetta, R.; Walsh, A.M.; Wedenig, R.; Weilhammer, P.; Ziock, H.; Zoeller, M.

1999-01-01

CVD diamond shows promising properties for use as a position-sensitive detector for experiments in the highest radiation areas at the Large Hadron Collider. In order to study the radiation hardness of diamond we exposed CVD diamond detector samples to 24 Gev/c and 500 Mev protons up to a fluence of 5x10 15 p/cm 2 . We measured the charge collection distance, the average distance electron-hole pairs move apart in an external electric field, and leakage currents before, during, and after irradiation. The charge collection distance remains unchanged up to 1x10 15 p/cm 2 and decreases by ∼40% at 5x10 15 p/cm 2 . Leakage currents of diamond samples were below 1 pA before and after irradiation. The particle-induced currents during irradiation correlate well with the proton flux. In contrast to diamond, a silicon diode, which was irradiated for comparison, shows the known large increase in leakage current. We conclude that CVD diamond detectors are radiation hard to 24 GeV/c and 500 MeV protons up to at least 1x10 15 p/cm 2 without signal loss

High-speed optical coherence tomography signal processing on GPU

International Nuclear Information System (INIS)

Li Xiqi; Shi Guohua; Zhang Yudong

2011-01-01

The signal processing speed of spectral domain optical coherence tomography (SD-OCT) has become a bottleneck in many medical applications. Recently, a time-domain interpolation method was proposed. This method not only gets a better signal-to noise ratio (SNR) but also gets a faster signal processing time for the SD-OCT than the widely used zero-padding interpolation method. Furthermore, the re-sampled data is obtained by convoluting the acquired data and the coefficients in time domain. Thus, a lot of interpolations can be performed concurrently. So, this interpolation method is suitable for parallel computing. An ultra-high optical coherence tomography signal processing can be realized by using graphics processing unit (GPU) with computer unified device architecture (CUDA). This paper will introduce the signal processing steps of SD-OCT on GPU. An experiment is performed to acquire a frame SD-OCT data (400A-linesx2048 pixel per A-line) and real-time processed the data on GPU. The results show that it can be finished in 6.208 milliseconds, which is 37 times faster than that on Central Processing Unit (CPU).

Ultra-low-energy wide electron exposure unit

International Nuclear Information System (INIS)

Yonago, Akinobu; Oono, Yukihiko; Tokunaga, Kazutoshi; Kishimoto, Junichi; Wakamoto, Ikuo

2001-01-01

Heat and ultraviolet ray processes are used in surface dryness of paint, surface treatment of construction materials and surface sterilization of food containers. A process using a low-energy wide-area electron beam (EB) has been developed that features high speed and low drive cost. EB processing is not widespread in general industry, however, due to high equipment cost and difficult maintenance. We developed an ultra-low-energy wide-area electron beam exposure unit, the Mitsubishi Wide Electron Exposure Unit (MIWEL) to solve these problems. (author)

Synthetic diamond in electrochemistry

International Nuclear Information System (INIS)

Pleskov, Yurii V

1999-01-01

The results of studies on the electrochemistry of diamond carried out during the last decade are reviewed. Methods for the preparation, the crystalline structure and the main electrophysical properties of diamond thin films are considered. Depending on the doping conditions, the diamond behaves as a superwide-gap semiconductor or as a semimetal. It is shown that the 'metal-like' diamond is corrosion-resistant and can be used advantageously as an electrode in the electrosynthesis (in particular, for the electroreduction of compounds that are difficult to reduce) and electroanalysis. Kinetic characteristics of some redox reactions and the impedance parameters for diamond electrodes are presented. The results of comparative studies of the electrodes made of diamond single crystals, polycrystalline diamond and amorphous diamond-like carbon, which reveal the effect of the crystalline structure (e.g., the influence of intercrystallite boundaries) on the electrochemical properties of diamond, are presented. The bibliography includes 99 references.

The high speed civil transport and NASA's High Speed Research (HSR) program

Science.gov (United States)

Shaw, Robert J.

1994-01-01

Ongoing studies being conducted not only in this country but in Europe and Asia suggest that a second generation supersonic transport, or High-Speed Civil Transport (HSCT), could become an important part of the 21st century international air transportation system. However, major environmental compatibility and economic viability issues must be resolved if the HSCT is to become a reality. This talk will overview the NASA High-Speed Research (HSR) program which is aimed at providing the U.S. industry with a technology base to allow them to consider launching an HSCT program early in the next century. The talk will also discuss some of the comparable activities going on within Europe and Japan.

Probing Growth-Induced Anisotropic Thermal Transport in High-Quality CVD Diamond Membranes by Multifrequency and Multiple-Spot-Size Time-Domain Thermoreflectance.

Science.gov (United States)

Cheng, Zhe; Bougher, Thomas; Bai, Tingyu; Wang, Steven Y; Li, Chao; Yates, Luke; Foley, Brian M; Goorsky, Mark; Cola, Baratunde A; Faili, Firooz; Graham, Samuel

2018-02-07

The maximum output power of GaN-based high-electron mobility transistors is limited by high channel temperature induced by localized self-heating, which degrades device performance and reliability. Chemical vapor deposition (CVD) diamond is an attractive candidate to aid in the extraction of this heat and in minimizing the peak operating temperatures of high-power electronics. Owing to its inhomogeneous structure, the thermal conductivity of CVD diamond varies along the growth direction and can differ between the in-plane and out-of-plane directions, resulting in a complex three-dimensional (3D) distribution. Depending on the thickness of the diamond and size of the electronic device, this 3D distribution may impact the effectiveness of CVD diamond in device thermal management. In this work, time-domain thermoreflectance is used to measure the anisotropic thermal conductivity of an 11.8 μm-thick high-quality CVD diamond membrane from its nucleation side. Starting with a spot-size diameter larger than the thickness of the membrane, measurements are made at various modulation frequencies from 1.2 to 11.6 MHz to tune the heat penetration depth and sample the variation in thermal conductivity. We then analyze the data by creating a model with the membrane divided into ten sublayers and assume isotropic thermal conductivity in each sublayer. From this, we observe a two-dimensional gradient of the depth-dependent thermal conductivity for this membrane. The local thermal conductivity goes beyond 1000 W/(m K) when the distance from the nucleation interface only reaches 3 μm. Additionally, by measuring the same region with a smaller spot size at multiple frequencies, the in-plane and cross-plane thermal conductivities are extracted. Through this use of multiple spot sizes and modulation frequencies, the 3D anisotropic thermal conductivity of CVD diamond membrane is experimentally obtained by fitting the experimental data to a thermal model. This work provides an improved

Bending diamonds by femtosecond laser ablation

DEFF Research Database (Denmark)

Balling, Peter; Esberg, Jakob; Kirsebom, Kim

2009-01-01

We present a new method based on femtosecond laser ablation for the fabrication of statically bent diamond crystals. Using this method, curvature radii of 1 m can easily be achieved, and the curvature obtained is very uniform. Since diamond is extremely tolerant to high radiation doses, partly due...

Structure and properties of diamond and diamond-like films

Energy Technology Data Exchange (ETDEWEB)

Clausing, R.E. [Oak Ridge National Lab., TN (United States)

1993-01-01

This section is broken into four parts: (1) introduction, (2) natural IIa diamond, (3) importance of structure and composition, and (4) control of structure and properties. Conclusions of this discussion are that properties of chemical vapor deposited diamond films can compare favorably with natural diamond, that properties are anisotropic and are a strong function of structure and crystal perfection, that crystal perfection and morphology are functions of growth conditions and can be controlled, and that the manipulation of texture and thereby surface morphology and internal crystal perfection is an important step in optimizing chemically deposited diamond films for applications.

Spalling behavior and residual resistance of fibre reinforced Ultra-High performance concrete after exposure to high temperatures

Directory of Open Access Journals (Sweden)

Xiong, Ming-Xiang

2015-12-01

Full Text Available Experimental results of spalling and residual mechanical properties of ultra-high performance concrete after exposure to high temperatures are presented in this paper. The compressive strength of the ultra-high performance concrete ranged from 160 MPa~185 MPa. This study aimed to discover the effective way to prevent spalling for the ultra-high performance concrete and gauge its mechanical properties after it was subjected to fire. The effects of fiber type, fiber dosage, heating rate and curing condition were investigated. Test results showed that the compressive strength and elastic modulus of the ultra-high performance concrete declined slower than those of normal strength concrete after elevated temperatures. Polypropylene fiber rather than steel fiber was found effective to prevent spalling but affected workability. The effective fiber type and dosage were recommended to prevent spalling and ensure sufficient workability for casting and pumping of the ultra-high performance concrete.En este trabajo se presentan los resultados más relevantes del trabajo experimental realizado para valorar la laminación y las propiedades mecánicas residuales de hormigón de ultra-altas prestaciones tras su exposición a altas temperaturas. La resistencia a la compresión del hormigón de ultra-altas prestaciones osciló entre 160 MPa~185 MPa. El objetivo de este estudio fue descubrir una manera eficaz de prevenir desprendimientos y/o laminaciones en este hormigón y medir sus propiedades mecánicas después de ser sometido al fuego. Las variables estudiadas fueron la presencia y dosificación de fibras, velocidad de calentamiento y condiciones de curado. Los resultados mostraron, tras la exposición a altas temperaturas, que la resistencia a compresión y el módulo de elasticidad del hormigón de ultra-altas prestaciones disminuían más lento que las de un hormigón con resistencia normal. La fibra de polipropileno resultó más eficaz para prevenir

Ultra-high-speed oscillographic techniques; Techniques d'oscillographie ultra-rapide; Metody sverkhskorostnoj ostsillografii; Metodos oscilograficos ultrarrapidos

Energy Technology Data Exchange (ETDEWEB)

Abercrombie, S; Elphick, B; Foster, H [Atomic Weapons Research Establishment, Aldermaston (United Kingdom)

1962-04-15

After a brief history of high-speed transient oscillograph technique, the practical limitations are discussed. A survey of suitable cathode-ray tubes is presented with particular reference to travelling-wave deflection types. The following components of a complete transient signal oscillograph are dealt with: (a) A travelling-wave (TW) deflector cathode-ray tube with balanced co-axial connection, and a bandwidth of 2 GHz; (b) A phase-splitting transformer of 100 and 50-{Omega} characteristic impedance and a bandwidth of 1.5 kHz to 1.5 GHz; (c) Co-axial terminating resistors with GHz performance; (d) Coupling capacitors, compensated for inclusion in co-axial lines for the frequency range 5 kHz - 3 GHz, with characteristic impedances of 100 {Omega}; (e) Wide band resistive pads for the extraction of timebase triggering signals; ( / ) Nanosecond timebases with triggering and blanking facilities; (g) A wide-aperture camera is described. In conclusion, nuclear-electronics applications, are discussed. (author) [French] Apres avoir brievement relate l'evolution de la technique d'emploi des oscillographes transistoires ultra-rapides, le memoire examine les limites de l'application pratique de cette technique. Il passe ensuite en revue les tubes a rayons cathodiques qui se pretent a cet usage en s'attachant plus particulierement aux tubes de deflexion d'ondes progressives. Les auteurs decrivent les elements constitutifs ci-apres des oscillographes a signal transistoire: a) Un tube cathodique de deflexion d'ondes progressives et a connexion equilibree coaxiale; largeur de bande: 2 GHz; b) Un transformateur coupeur de phase d'une impedance caracteristique de 100 et 50 {Omega}; largeur de bande: de 1,5 kHz a 1,5 GHz; c) Des termineurs coaxiaux capables de transmettre des frequences se comptant par GHz; d) Des condensateurs de couplage compenses pour inclusion dans des lignes coaxiales, couvrant la bande de frequences de 5 kHz a 3 GHz et ayant une impedance caracteristique de

Using a High-Speed Camera to Measure the Speed of Sound

Science.gov (United States)

Hack, William Nathan; Baird, William H.

2012-01-01

The speed of sound is a physical property that can be measured easily in the lab. However, finding an inexpensive and intuitive way for students to determine this speed has been more involved. The introduction of affordable consumer-grade high-speed cameras (such as the Exilim EX-FC100) makes conceptually simple experiments feasible. Since the…

P-type diamond stripper foils for tandem ion accelerators

International Nuclear Information System (INIS)

Phelps, A.W.; Koba, R.

1989-01-01

The authors are developing a stripper foil composed of a p-type diamond membrane. This diamond stripper foil should have a significantly longer lifetime than any conventional stripper foil material. To be useful for stripper foils, the boron-doped blue diamond films must be thinner than 0.8 μm and pore-free. Two methods are compared for their ability to achieve a high nucleation areal density on a W substrate. Some W substrates were first coated with think layer of boron (≤20 nm) in order to enhance nucleation. Other W substrates were scratched with submicron diamond particles. A schematic diagram of the stripper foil is shown. Stripper foils were created by etching away the central area of W substrates. The diamond membrane was then supported by an annulus of W. Tungsten was selected as a ring-support material because of its high electrical and thermal conductivity, relatively low thermal expansion, and proven suitability as a substrate for diamond CVD. Warping or fracture of the diamond film after substrate etch-back was investigated

Nanofocusing optics for synchrotron radiation made from polycrystalline diamond.

Science.gov (United States)

Fox, O J L; Alianelli, L; Malik, A M; Pape, I; May, P W; Sawhney, K J S

2014-04-07

Diamond possesses many extreme properties that make it an ideal material for fabricating nanofocusing x-ray optics. Refractive lenses made from diamond are able to focus x-ray radiation with high efficiency but without compromising the brilliance of the beam. Electron-beam lithography and deep reactive-ion etching of silicon substrates have been used in a transfer-molding technique to fabricate diamond optics with vertical and smooth sidewalls. Latest generation compound refractive lenses have seen an improvement in the quality and uniformity of the optical structures, resulting in an increase in their focusing ability. Synchrotron beamline tests of two recent lens arrays, corresponding to two different diamond morphologies, are described. Focal line-widths down to 210 nm, using a nanocrystalline diamond lens array and a beam energy of E = 11 keV, and 230 nm, using a microcrystalline diamond lens at E = 15 keV, have been measured using the Diamond Light Source Ltd. B16 beamline. This focusing prowess is combined with relatively high transmission through the lenses compared with silicon refractive designs and other diffractive optics.

High-speed data acquisition with the Solaris and Linux operating systems

International Nuclear Information System (INIS)

Zilker, M.; Heimann, P.

2000-01-01

In this paper, we discuss whether Solaris and Linux are suitable for data acquisition systems in soft real time conditions. As an example we consider a plasma diagnostic (Mirnov coils), which collects data for a complete plasma discharge of about 10 s from up to 72 channels. Each ADC-Channel generates a data stream of 4 MB/s. To receive these data streams an eight-channel Hotlink PCI interface board was designed. With a prototype system using Solaris and the driver developed by us we investigate important properties of the operating system such as the I/O performance and scheduling of processes. We compare the Solaris operating system on the Ultra Sparc platform with Linux on the Intel platform. Finally, some points of user program development are mentioned to show how the application can make the most efficient use of the underlying high-speed I/O system

33 CFR 84.24 - High-speed craft.

Science.gov (United States)

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false High-speed craft. 84.24 Section... RULES ANNEX I: POSITIONING AND TECHNICAL DETAILS OF LIGHTS AND SHAPES § 84.24 High-speed craft. (a) The masthead light of high-speed craft with a length to breadth ratio of less than 3.0 may be placed at a...

Neurocognitive performance of a community-based sample of young people at putative ultra high risk for psychosis: support for the processing speed hypothesis.

LENUS (Irish Health Repository)

Kelleher, Ian

2013-01-01

A wide variety of neurocognitive deficits have been reported for help-seeking individuals who are at clinical or ultra high risk for psychosis based on fulfilling set criteria for prodromal syndromes\\/at risk mental states. We wished to extend this research by conducting the first population-based assessment of prodromal syndromes and associated neurocognition.

Ultra-high pressure water jet: Baseline report

International Nuclear Information System (INIS)

1997-01-01

The ultra-high pressure waterjet technology was being evaluated at Florida International University (FIU) as a baseline technology. In conjunction with FIU's evaluation of efficiency and cost, this report covers the evaluation conducted for safety and health issues. It is a commercially available technology and has been used for various projects at locations throughout the country. The ultra-high pressure waterjet technology acts as a cutting tool for the removal of surface substrates. The Husky trademark pump feeds water to a lance that directs the high pressure water at the surface to be removed. The safety and health evaluation during the testing demonstration focused on two main areas of exposure. These were dust and noise. The dust exposure was found to be minimal, which would be expected due to the wet environment inherent in the technology, but noise exposure was at a significant level. Further testing for noise is recommended because of the outdoor environment where the testing demonstration took place. In addition, other areas of concern found were arm-hand vibration, ergonomics, heat stress, tripping hazards, electrical hazards, lockout/tagout, fall hazards, slipping hazards, hazards associated with the high pressure water, and hazards associated with air pressure systems

Modified Hermite Pulse-Based Wideband Communication for High-Speed Data Transfer in Wireless Sensor Applications

Directory of Open Access Journals (Sweden)

Kushal P. Pradhan

2017-12-01

Full Text Available With technological advances in the field of communication, the need for reliable high-speed data transfer is increasing. The deployment of large number of wireless sensors for remote monitoring and control and streaming of high definition video, voice and image data, etc. are imposing a challenge to the existing network bandwidth allocation for reliable communication. Two novel schemes for ultra-wide band (UWB communication technology have been proposed in this paper with the key objective of intensifying the data rate by taking advantage of the orthogonal properties of the modified Hermite pulse (MHP. In the first scheme, a composite pulse is transmitted and in the second scheme, a sequence of multi-order orthogonal pulses is transmitted in the place of a single UWB pulse. The MHP pulses exhibit a mutually orthogonal property between different ordered pulses and due to this property, simultaneous transmission is achieved without collision in the UWB system, resulting in an increase in transmission capacity or improved bit error rate. The proposed schemes for enhanced data rate will offer high volume data monitoring, assessment, and control of wireless devices without overburdening the network bandwidth and pave the way for new platforms for future high-speed wireless sensor applications.

Modern trends in designing high-speed trains

Directory of Open Access Journals (Sweden)

Golubović Snežana D.

2015-01-01

Full Text Available Increased advantages of railway transportation systems over other types of transportation systems in the past sixty years have been a result of an intensive development of the new generations of high-speed trains. Not only do these types of trains comply with the need for increased speed of transportation and make the duration of the journey shorter, but they also meet the demands for increased reliability, safety and direct application of energy efficiency to the transportation system itself. Along with increased train speed, the motion resistance is increased as well, whereby at speeds over 200 km/h the proportion of air resistance becomes the most dominant member. One of the most efficient measures for reducing air resistance, as well as other negative consequences of high-speed motion, is the development of the aerodynamic shape of the train. This paper presents some construction solutions that affect the aerodynamic properties of high-speed trains, first and foremost, the nose shape, as well as the similarities and differences of individual subsystems necessary for the functioning of modern high-speed rail systems. We analysed two approaches to solving the problem of the aerodynamic shape of the train and the appropriate infrastructure using the examples of Japan and France. Two models of high-speed trains, Shinkansen (Japan and TGV, i.e. AGV (France, have been discussed.

Effect of substrates on tribological properties of diamond-like carbon coating

Directory of Open Access Journals (Sweden)

Renhui ZHANG

2017-06-01

Full Text Available In order to well investigate the effect of different substrates on the friction and wear of diamond-like carbon (DLC coating, the DLC coatings are deposited on substrates like the high-speed steel (HSS, SiC and 304 stainless steel by using plasma enhanced chemical vapor deposition method. The diamond-like carbon is prepared. The microstructure of the coatings is characterized using SEM, TEM and Raman. The SEM results exhibit that the total thickness of the coatings is about 6.5 μm, and there's apparent interfaces between layers. The TEM results imply that the coatings have an amorphous structure. Raman spectrum exhibits that G and D peaks are observed, which implies that the deposition coatings are diamond-like carbon coating. The results of tribological tests show that the substrates have a significant effect on the friction and wear of the coating. For different substrates, the transfer film is found on the steel counterpart surface, the wear track of the HSS has a lowest width, and the DLC coating that deposited on HSS exhibits the lowest wear and low friction coefficient (about 0.1.The microstructure of different substrates wear track surfaces is analyzed by using Raman spectrum, and the lowest wear of the HSS is attributed to the lower degree of the graphitization. The research provides reference for preparing the DLC coating with excellent tribological properties.

Neutron detection at jet using artificial diamond detectors

International Nuclear Information System (INIS)

Pillon, M.; Angelone, M.; Lattanzi, D.; Marinelli, M.; Milani, E.; Tucciarone, A.; Verona-Rinati, G.; Popovichev, S.; Montereali, R.M.; Vincenti, M.A.; Murari, A.

2007-01-01

Artificial diamond neutron detectors recently proved to be promising devices to measure the neutron production on large experimental fusion machines. Diamond detectors are very promising detectors to be used in fusion environment due to their radiation hardness, low sensitivity to gamma rays, fast response and high energy resolution. High quality 'electronic grade' diamond films are produced through microwave chemical vapour deposition (CVD) technique. Two CVD diamond detectors have been installed and operated at joint European torus (JET), Culham Science Centre, UK. One of these detectors was a polycrystalline CVD diamond film; about 12 mm 2 area and 30 μm thickness while the second was a monocrystalline film of about 5 mm 2 area and 20 μm thick. Both diamonds were covered with 2 μm of lithium fluoride (LiF) 95% enriched in 6 Li. The LiF layer works as a neutron-to-charged particle converter so these detectors can measure thermalized neutrons. Their output signals were compared to JET total neutron yield monitors (KN1 diagnostic) realized with a set of uranium fission chambers. Despite their small active volumes the diamond detectors were able to measure total neutron yields with good reliability and stability during the recent JET experimental campaign of 2006

In-situ Raman spectroscopy and high-speed photography of a shocked triaminotrinitrobenzene based explosive

Energy Technology Data Exchange (ETDEWEB)

Saint-Amans, C.; Hébert, P., E-mail: philippe.hebert@cea.fr; Doucet, M. [CEA, DAM, Le RIPAULT, F-37620 Monts (France); Resseguier, T. de [Institut P' , UPR CNRS 3346, ENSMA, Université de Poitiers, F-86961 Futuroscope, Chasseneuil (France)

2015-01-14

We have developed a single-shot Raman spectroscopy experiment to study at the molecular level the initiation mechanisms that can lead to sustained detonation of a triaminotrinitrobenzene-based explosive. Shocks up to 30 GPa were generated using a two-stage laser-driven flyer plate generator. The samples were confined by an optical window and shock pressure was maintained for at least 30 ns. Photon Doppler Velocimetry measurements were performed at the explosive/window interface to determine the shock pressure profile. Raman spectra were recorded as a function of shock pressure and the shifts of the principal modes were compared to static high-pressure measurements performed in a diamond anvil cell. Our shock data indicate the role of temperature effects. Our Raman spectra also show a progressive extinction of the signal which disappears around 9 GPa. High-speed photography images reveal a simultaneous progressive darkening of the sample surface up to total opacity at 9 GPa. Reflectivity measurements under shock compression show that this opacity is due to a broadening of the absorption spectrum over the entire visible region.

High dose-rate brachytherapy source localization: positional resolution using a diamond detector

International Nuclear Information System (INIS)

Nakano, T; Suchowerska, N; Bilek, M M; McKenzie, D R; Ng, N; Kron, T

2003-01-01

A potential real-time source position verification process for high dose-rate (HDR) brachytherapy treatment is described. This process is intended to provide immediate confirmation that a treatment is proceeding according to plan, so that corrective action can be taken if necessary. We show that three dosimeters are in principle sufficient and demonstrate the feasibility of the process using a diamond detector and an Ir-192 source. An error analysis including all identified sources of error shows that this detector is capable of locating the distance to the source to within 2 mm for distances up to 12 cm. This positional accuracy is less than the diameter of typical HDR catheters indicating that a diamond detector can be used to accurately determine the distance to the source. The uncertainty in the distance is found to increase with distance

Highly-focused boron implantation in diamond and imaging using the nuclear reaction {sup 11}B(p, α){sup 8}Be

Energy Technology Data Exchange (ETDEWEB)

Ynsa, M.D., E-mail: m.ynsa@uam.es [Centro de Micro-Análisis de Materiales, Universidad Autónoma de Madrid, E-28049 Madrid (Spain); Departamento de Física Aplicada, Universidad Autónoma de Madrid, E-28049 Madrid (Spain); Ramos, M.A. [Centro de Micro-Análisis de Materiales, Universidad Autónoma de Madrid, E-28049 Madrid (Spain); Departamento de Física de la Materia Condensada and Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, E-28049 Madrid (Spain); Skukan, N. [Laboratory for Ion Beam Interactions, Ruđer Bošković Institute, Bijenička 54, HR-10000 Zagreb (Croatia); Torres-Costa, V. [Centro de Micro-Análisis de Materiales, Universidad Autónoma de Madrid, E-28049 Madrid (Spain); Departamento de Física Aplicada, Universidad Autónoma de Madrid, E-28049 Madrid (Spain); Jakšić, M. [Laboratory for Ion Beam Interactions, Ruđer Bošković Institute, Bijenička 54, HR-10000 Zagreb (Croatia)

2015-04-01

Diamond is an especially attractive material because of its gemological value as well as its unique mechanical, chemical and physical properties. One of these properties is that boron-doped diamond is an electrically p-type semiconducting material at practically any boron concentration. This property makes it possible to use diamonds for multiple industrial and technological applications. Boron can be incorporated into pure diamond by different techniques including ion implantation. Although typical energies used to dope diamond by ion implantation are about 100 keV, implantations have also been performed with energies above MeV. In this work CMAM microbeam setup has been used to demonstrate capability to implant boron with high energies. An 8 MeV boron beam with a size of about 5 × 3 μm{sup 2} and a beam current higher than 500 pA has been employed while controlling the beam position and fluence at all irradiated areas. The subsequent mapping of the implanted boron in diamond has been obtained using the strong and broad nuclear reaction {sup 11}B(p, α){sup 8}Be at E{sub p} = 660 keV. This reaction has a high Q-value (8.59 MeV for α{sub 0} and 5.68 MeV for α{sub 1}) and thus is almost interference-free. The sensitivity of the technique is studied in this work.

Residual radioactivity of treated green diamonds.

Science.gov (United States)

Cassette, Philippe; Notari, Franck; Lépy, Marie-Christine; Caplan, Candice; Pierre, Sylvie; Hainschwang, Thomas; Fritsch, Emmanuel

2017-08-01

Treated green diamonds can show residual radioactivity, generally due to immersion in radium salts. We report various activity measurements on two radioactive diamonds. The activity was characterized by alpha and gamma ray spectrometry, and the radon emanation was measured by alpha counting of a frozen source. Even when no residual radium contamination can be identified, measurable alpha and high-energy beta emissions could be detected. The potential health impact of radioactive diamonds and their status with regard to the regulatory policy for radioactive products are discussed. Copyright © 2017. Published by Elsevier Ltd.

Nanostructured Diamond Device for Biomedical Applications.

Science.gov (United States)

Fijalkowski, M; Karczemska, A; Lysko, J M; Zybala, R; KozaneckI, M; Filipczak, P; Ralchenko, V; Walock, M; Stanishevsky, A; Mitura, S

2015-02-01

Diamond is increasingly used in biomedical applications because of its unique properties such as the highest thermal conductivity, good optical properties, high electrical breakdown voltage as well as excellent biocompatibility and chemical resistance. Diamond has also been introduced as an excellent substrate to make the functional microchip structures for electrophoresis, which is the most popular separation technique for the determination of analytes. In this investigation, a diamond electrophoretic chip was manufactured by a replica method using a silicon mold. A polycrystalline 300 micron-thick diamond layer was grown by the microwave plasma-assisted CVD (MPCVD) technique onto a patterned silicon substrate followed by the removal of the substrate. The geometry of microstructure, chemical composition, thermal and optical properties of the resulting free-standing diamond electrophoretic microchip structure were examined by CLSM, SFE, UV-Vis, Raman, XRD and X-ray Photoelectron Spectroscopy, and by a modified laser flash method for thermal property measurements.

Performance and characterisation of CVD diamond coated, sintered diamond and WC-Co cutting tools for dental and micromachining applications

International Nuclear Information System (INIS)

Sein, Htet; Ahmed, Waqar; Jackson, Mark; Woodwards, Robert; Polini, Riccardo

2004-01-01

Diamond coatings are attractive for cutting processes due to their high hardness, low friction coefficient, excellent wear resistance and chemical inertness. The application of diamond coatings on cemented tungsten carbide (WC-Co) tools was the subject of much attention in recent years in order to improve cutting performance and tool life. WC-Co tools containing 6% Co and 94% WC substrate with an average grain size 1-3 μm were used in this study. In order to improve the adhesion between diamond and WC substrates, it is necessary to etch away the surface Co and prepare the surface for subsequent diamond growth. Hot filament chemical vapour deposition with a modified vertical filament arrangement has been employed for the deposition of diamond films. Diamond film quality and purity have been characterised using scanning electron microscopy and micro-Raman spectroscopy. The performance of diamond coated WC-Co bur, uncoated WC-Co bur, and diamond embedded (sintered) bur have been compared by drilling a series of holes into various materials such as human teeth, borosilicate glass and porcelain teeth. Flank wear has been used to assess the wear rates of the tools. The materials subjected to cutting processes have been examined to assess the quality of the finish. Diamond coated WC-Co microdrills and uncoated microdrills were also tested on aluminium alloys. Results show that there was a 300% improvement when the drills were coated with diamond compared to the uncoated tools

Changes of indicators of high-speed and high-speed and power preparedness at volleyball players of 12–13 years old

Directory of Open Access Journals (Sweden)

Oleg Shevchenko

2016-04-01

Full Text Available Purpose: to define changes of indicators of high-speed and high-speed and power preparedness of volleyball players of 12–13 years old. Material & Methods: the test exercises, which are recommended by the training program of CYSS on volleyball, were used for the definition of the level of development of high-speed and high-speed and power abilities of volleyball players. 25 young volleyball players from the group of the previous basic preparation took part in the experiment. Sports experience of sportsmen is 3–4 years. The analysis of scientifically-methodical literature, pedagogical testing, pedagogical experiment, methods of mathematical statistics were carried out. Results: the analyzed level of high-speed and high-speed and power abilities of volleyball players. Conclusions: the results had reliable changes (t=2,2–2,4 at р<0,05 of the level of high-speed and high-speed and power abilities of volleyball players of 12–13years old in the experimental group at the end of the experiment, except run on 30 m that demonstrates a positive influence of application of special exercises in the educational-training process.

FY 1999 report on the results of the R and D of femtosecond technology. Development of ultra-short pulse optoelectronics technology; 1999 nendo femutobyo technology no kenkyu kaihatsu seika hokokusho. Chotan pulse hikari electronics gijutsu kaihatsu

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-03-01

The paper described the FY 1999 results of the R and D of femtosecond technology. For the purpose of creating new industrial basement technology which supports the highly information-oriented society in the 21st century, the ultra-high speed electronics technology is indispensable which is beyond speed limits of the existing electronics technology and has new functionality. The ultra-high speed electronics basement technology is established through the R and D of the technology to control the state of light and electronics in the femtosecond time domain (10{sup -15} - 10{sup -12} second). Themes of the R and D are technology to generate/transmit femtosecond optical pulse, technology for control/distribution, and ultra-short pulse optoelectronics common basement technology. In FY 1999, a lot of results were obtained in the following: generation of the pulse train highly repeated at 500GHz in semiconductor laser; 139km transmission of 250fs optical pulse; switching movement at ultra-high speed of 150fs-1.2ps in transition among subbands of GaN base and Sb base materials; DEMUXA movement toward 160-10Gb/s in Mach-Zehnder type optical switch. (NEDO)