Surface micromachined counter-meshing gears discrimination device

International Nuclear Information System (INIS)

Polosky, M.A.; Garcia, E.J.; Allen, J.J.

1998-01-01

This paper discusses the design, fabrication and testing of a surface micromachined Counter-Meshing Gears (CMG) discrimination device which functions as a mechanically coded lock, A 24 bit code is input to unlock the device. Once unlocked, the device provides a path for an energy or information signal to pass through the device. The device is designed to immediately lock up if any portion of the 24 bit code is incorrect. The motivation for the development of this device is based on occurrences referred to as High Consequence Events, A High Consequence Event is an event where an inadvertent operation of a system could result in the catastrophic loss of life, property, or damage to the environment

Surface micromachined fabrication of piezoelectric ain unimorph suspension devices for rf resonator applications

NARCIS (Netherlands)

Saravanan, S.; Saravanan, S.; Berenschot, Johan W.; Krijnen, Gijsbertus J.M.; Elwenspoek, Michael Curt

We report a surface micromachining process for aluminum nitride (AlN) thin films to fabricate piezoelectric unimorph suspension devices for actuator applications. Polysilicon is used as a structural layer. Highly c-axis oriented AlN thin films 1 /spl mu/m thick are deposited by rf reactive

Micromachined sensor and actuator research at Sandia`s Microelectronics Development Laboratory

Energy Technology Data Exchange (ETDEWEB)

Smith, J.H.

1996-11-01

An overview of the surface micromachining program at the Microelectronics Development Laboratory of Sandia National Laboratories is presented. Development efforts are underway for a variety of surface micromachined sensors and actuators for both defense and commercial applications. A technology that embeds micromechanical devices below the surface of the wafer prior to microelectronics fabrication has been developed for integrating microelectronics with surface-micromachined micromechanical devices. The application of chemical-mechanical polishing to increase the manufacturability of micromechanical devices is also presented.

High definition surface micromachining of LiNbO 3 by ion implantation

Science.gov (United States)

Chiarini, M.; Bentini, G. G.; Bianconi, M.; De Nicola, P.

2010-10-01

High Energy Ion Implantation (HEII) of both medium and light mass ions has been successfully applied for the surface micromachining of single crystal LiNbO 3 (LN) substrates. It has been demonstrated that the ion implantation process generates high differential etch rates in the LN implanted areas, when suitable implantation parameters, such as ion species, fluence and energy, are chosen. In particular, when traditional LN etching solutions are applied to suitably ion implanted regions, etch rates values up to three orders of magnitude higher than the typical etching rates of the virgin material, are registered. Further, the enhancement in the etching rate has been observed on x, y and z-cut single crystalline material, and, due to the physical nature of the implantation process, it is expected that it can be equivalently applied also to substrates with different crystallographic orientations. This technique, associated with standard photolithographic technologies, allows to generate in a fast and accurate way very high aspect ratio relief micrometric structures on LN single crystal surface. In this work a description of the developed technology is reported together with some examples of produced micromachined structures: in particular very precisely defined self sustaining suspended structures, such as beams and membranes, generated on LN substrates, are presented. The developed technology opens the way to actual three dimensional micromachining of LN single crystals substrates and, due to the peculiar properties characterising this material, (pyroelectric, electro-optic, acousto-optic, etc.), it allows the design and the production of complex integrated elements, characterised by micrometric features and suitable for the generation of advanced Micro Electro Optical Systems (MEOS).

Fabrication of surface micromachined ain piezoelectric microstructures and its potential apllication to rf resonators

NARCIS (Netherlands)

Saravanan, S.; Saravanan, S.; Berenschot, Johan W.; Krijnen, Gijsbertus J.M.; Elwenspoek, Michael Curt

2005-01-01

We report on a novel microfabrication method to fabricate aluminum nitride (AlN) piezoelectric microstructures down to 2 microns size by a surface micromachining process. Highly c-axis oriented AlN thin films are deposited between thin Cr electrodes on polysilicon structural layers by rf reactive

The Development of Micromachined Gyroscope Structure and Circuitry Technology

Directory of Open Access Journals (Sweden)

Dunzhu Xia

2014-01-01

Full Text Available This review surveys micromachined gyroscope structure and circuitry technology. The principle of micromachined gyroscopes is first introduced. Then, different kinds of MEMS gyroscope structures, materials and fabrication technologies are illustrated. Micromachined gyroscopes are mainly categorized into micromachined vibrating gyroscopes (MVGs, piezoelectric vibrating gyroscopes (PVGs, surface acoustic wave (SAW gyroscopes, bulk acoustic wave (BAW gyroscopes, micromachined electrostatically suspended gyroscopes (MESGs, magnetically suspended gyroscopes (MSGs, micro fiber optic gyroscopes (MFOGs, micro fluid gyroscopes (MFGs, micro atom gyroscopes (MAGs, and special micromachined gyroscopes. Next, the control electronics of micromachined gyroscopes are analyzed. The control circuits are categorized into typical circuitry and special circuitry technologies. The typical circuitry technologies include typical analog circuitry and digital circuitry, while the special circuitry consists of sigma delta, mode matching, temperature/quadrature compensation and novel special technologies. Finally, the characteristics of various typical gyroscopes and their development tendency are discussed and investigated in detail.

Surface micromachined counter-meshing gears discrimination device

Science.gov (United States)

Polosky, Marc A.; Garcia, Ernest J.; Allen, James J.

2000-12-12

A surface micromachined Counter-Meshing Gears (CMG) discrimination device which functions as a mechanically coded lock. Each of two CMG has a first portion of its perimeter devoted to continuous driving teeth that mesh with respective pinion gears. Each EMG also has a second portion of its perimeter devoted to regularly spaced discrimination gear teeth that extend outwardly on at least one of three levels of the CMG. The discrimination gear teeth are designed so as to pass each other without interference only if the correct sequence of partial rotations of the CMG occurs in response to a coded series of rotations from the pinion gears. A 24 bit code is normally input to unlock the device. Once unlocked, the device provides a path for an energy or information signal to pass through the device. The device is designed to immediately lock up if any portion of the 24 bit code is incorrect.

Omega-X micromachining system

International Nuclear Information System (INIS)

Miller, D.M.

1978-01-01

A micromachining tool system with X- and omega-axes is used to machine spherical, aspherical, and irregular surfaces with a maximum contour error of 100 nonometers (nm) and surface waviness of no more than 0.8 nm RMS. The omega axis, named for the angular measurement of the rotation of an eccentric mechanism supporting one end of a tool bar, enables the pulse increments of the tool toward the workpiece to be as little as 0 to 4.4 nm. A dedicated computer coordinates motion in the two axes to produce the workpiece contour. Inertia is reduced by reducing the mass pulsed toward the workpiece to about one-fifth of its former value. The tool system includes calibration instruments to calibrate the micromachining tool system. Backlash is reduced and flexing decreased by using a rotary table and servomotor to pulse the tool in the omega-axis instead of a ball screw mechanism. A thermally-stabilized spindle roates the workpiece and is driven by a motor not mounted on the micromachining tool base through a torque-smoothing pulley and vibrationless rotary coupling. Abbe offset errors are almost eliminated by tool setting and calibration at spindle center height. Tool contour and workpiece contour are gaged on the machine; this enables the source of machining errors to be determined more readily, because the workpiece is gaged before its shape can be changed by removal from the machine

Fabrication of piezoresistive microcantilever using surface micromachining technique for biosensors

Energy Technology Data Exchange (ETDEWEB)

Na, Kwang-Ho [Department of Electrical Engineering and Nano-Bio Research Center, Myongji University, Yongin, Gyeonggido 449-728 (Korea, Republic of); Kim, Yong-Sang [Department of Electrical Engineering and Nano-Bio Research Center, Myongji University, Yongin, Gyeonggido 449-728 (Korea, Republic of); Kang, C.J. [Department of Physics and Nano-Bio Research Center, Myongji University, San38-2 Namdong, Yongin, Gyeonggido 449-728 (Korea, Republic of)]. E-mail: cjkang@mju.ac.kr

2005-11-15

A microcantilever-based biosensor with piezoresistor has been fabricated using surface micromachining technique, which is cost effective and simplifies a fabrication procedure. In order to evaluate the characteristics of the cantilever, the cystamine terminated with thiol was covalently immobilized on the gold-coated side of the cantilever and glutaraldehyde that would be bonded with amine group in the cystamine was injected subsequently. This process was characterized by measuring the deflection of the cantilever in real time monitoring. Using a piezoresistive read-out and a well-known optical beam deflection method as well, the measurement of deflection was carried out. The sensitivity of piezoresistive method is good enough compared with that of optical beam deflection method.

UV laser micromachining of ceramic materials: formation of columnar topographies

International Nuclear Information System (INIS)

Oliveira, V.; Vilar, R.; Conde, O.

2001-01-01

Laser machining is increasingly appearing as an alternative for micromachining of ceramics. Using ceramic materials using excimer lasers can result in smooth surfaces or in the formation of cone-like or columnar topography. Potential applications of cone-shaped or columnar surface topography include, for example, light trapping in anti-reflection coatings and improvement of adhesion bonding between ceramic materials. In this communication results of a comparative study of surface topography change during micromachining of several ceramic materials with different ablation behaviors are reported. (orig.)

A novel surface micromachining process to fabricate AlN unimorph suspensions and its application for RF resonators

NARCIS (Netherlands)

Saravanan, S.; Saravanan, S.; Berenschot, Johan W.; Krijnen, Gijsbertus J.M.; Elwenspoek, Michael Curt

2006-01-01

A novel surface micromachining process is reported for aluminum nitride (AlN) thin films to fabricate piezoelectric unimorph suspension devices for micro actuator applications. Wet anisotropic etching of AlN thin film is used with a Cr metal mask layer in the microfabrication process. Tetra methyl

Modeling and identification of induction micromachines in microelectromechanical systems applications

Energy Technology Data Exchange (ETDEWEB)

Lyshevski, S.E. [Purdue University at Indianapolis (United States). Dept. of Electrical and Computer Engineering

2002-11-01

Microelectromechanical systems (MEMS), which integrate motion microstructures, radiating energy microdevices, controlling and signal processing integrated circuits (ICs), are widely used. Rotational and translational electromagnetic based micromachines are used in MEMS as actuators and sensors. Brushless high performance micromachines are the preferable choice in different MEMS applications, and therefore, synchronous and induction micromachines are the best candidates. Affordability, good performance characteristics (efficiency, controllability, robustness, reliability, power and torque densities etc.) and expanded operating envelopes result in a strong interest in the application of induction micromachines. In addition, induction micromachines can be easily fabricated using surface micromachining and high aspect ratio fabrication technologies. Thus, it is anticipated that induction micromachines, controlled using different control algorithms implemented using ICs, will be widely used in MEMS. Controllers can be implemented using specifically designed ICs to attain superior performance, maximize efficiency and controllability, minimize losses and electromagnetic interference, reduce noise and vibration, etc. In order to design controllers, the induction micromachine must be modeled, and its mathematical model parameters must be identified. Using microelectromechanics, nonlinear mathematical models are derived. This paper illustrates the application of nonlinear identification methods as applied to identify the unknown parameters of three phase induction micromachines. Two identification methods are studied. In particular, nonlinear error mapping technique and least squares identification are researched. Analytical and numerical results, as well as practical capabilities and effectiveness, are illustrated, identifying the unknown parameters of a three phase brushless induction micromotor. Experimental results fully support the identification methods. (author)

Micromachined silicon seismic accelerometer development

Energy Technology Data Exchange (ETDEWEB)

Barron, C.C.; Fleming, J.G.; Montague, S. [and others

1996-08-01

Batch-fabricated silicon seismic transducers could revolutionize the discipline of seismic monitoring by providing inexpensive, easily deployable sensor arrays. Our ultimate goal is to fabricate seismic sensors with sensitivity and noise performance comparable to short-period seismometers in common use. We expect several phases of development will be required to accomplish that level of performance. Traditional silicon micromachining techniques are not ideally suited to the simultaneous fabrication of a large proof mass and soft suspension, such as one needs to achieve the extreme sensitivities required for seismic measurements. We have therefore developed a novel {open_quotes}mold{close_quotes} micromachining technology that promises to make larger proof masses (in the 1-10 mg range) possible. We have successfully integrated this micromolding capability with our surface-micromachining process, which enables the formation of soft suspension springs. Our calculations indicate that devices made in this new integrated technology will resolve down to at least sub-{mu}G signals, and may even approach the 10{sup -10} G/{radical}Hz acceleration levels found in the low-earth-noise model.

A novel hybrid surface micromachined segmented mirror for large aperture laser applications

Science.gov (United States)

Li, Jie; Chen, Haiqing; Yu, Hongbin

2006-07-01

A novel hybrid surface micromachined segmented mirror array is described. This device is capable of scaling to large apertures for correcting time-varying aberrations in laser applications. Each mirror is composed of bottom electrode, support part, and mirror plate, in which a T-shaped beam structure is used to support the mirror plate. It can provide mirror with vertical movement and rotation around two horizontal axes. The test results show that the maximum deflection along the vertical direction of the mirror plate is 2 microns, while the rotation angles around x and y axes are +-2.3 deg. and +-1.45 deg., respectively.

Minimizing stress in large-area surface micromachined perforated membranes with slits

International Nuclear Information System (INIS)

Ghaderi, M; Ayerden, N P; De Graaf, G; Wolffenbuttel, R F

2015-01-01

This paper presents the effectiveness of both design and fabrication techniques for avoiding the rupturing or excessive bending of perforated membranes after release in surface micromachining. Special lateral designs of arrays of slits in the membrane were investigated for a maximum yield at a given level of residual stress. Process parameters were investigated and optimized for minimum residual stress in multilayer thin-film membranes. A 2 µm thick sacrificial TEOS layer and a structural membrane that is composed of silicon nitride and polysilicon layers in the stack is the basis of this study. The effect of sharp corners on the local stress in membranes was investigated, and structures are proposed that reduce these effects, maximizing the yield at a given level of residual stress. The effects of perforation and slits were studied both theoretically and using finite element analysis. While the overall effect of perforation is negligible in typical MEMS structures, an optimum design for the slits reduces the von Mises stress considerably as compared to sharp corners. The fabrication process was also investigated and optimized for the minimum residual stress of both the layers within the stack and the complete layer stack. The main emphasis of this work is on placing a stress-compensating layer on the wafer backside and simultaneously removing it during the surface micromachining, as this has been found to be the most effective method to reduce the overall stress in a stack of layers after sacrificial etching. Implementation of a stress compensating layer reduced the total residual stress from 200 MPa compressive into almost 60 MPa, tensile. Even though a particular structure was studied here, the employed methods are expected to be applicable to similar MEMS design problems. (paper)

FY 1998 report on the R and D of micromachine technology. R and D of micromachine technology; 1998 nendo micromachine gijutsu no kenkyu kaihatsu seika hokokusho

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-03-01

In the comprehensive investigational study of micromachine technology, the paper aims at clarifying the improvement of functional devices and the future development of micromachine technology for establishment of the technology needed to realize a micromachine system composing of small-functional elements for conducting diagnosis/cure/repair, movement and independent work in small portions in living organism, disaster site, etc. and a medical-use micromachine system to analyze/react on a trace of liquid. In this fiscal year, the following were carried out: 1) study of micromachine systems, 2) study of a medical-use micromachine system to analyze/react on a trace liquid, and 3) comprehensive investigational study. In 1), studies were made toward the minuteness and improvement of micro laser catheter and micro tactile sensor catheter as functional devices which become the main components of micro catheter for cerebrovascular diagnosis/therapy use and toward the minuteness and improvement of disaster relief use micromachine system. In 2), study was made of element technology of a micro-machine system having functions of sampling/analysis/reaction of a trace of liquid. (NEDO)

Determination of S-methyl-L-methionine (SMM) from Brassicaceae Family Vegetables and Characterization of the Intestinal Transport of SMM by Caco-2 Cells.

Science.gov (United States)

Song, Ji-Hoon; Lee, Hae-Rim; Shim, Soon-Mi

2017-01-01

The objectives of the current study were to determine S-methyl-L-methionine (SMM) from various Brassicaceae family vegetables by using validated analytical method and to characterize the intestinal transport mechanism of SMM by the Caco-2 cells. The SMM is well known to provide therapeutic activity in peptic ulcers. The amount of SMM from various Brassicaceae family vegetables ranged from 89.08 ± 1.68 μg/g to 535.98 ± 4.85 μg/g of dry weight by using validated ultra-performance liquid chromatography-electrospray ionization-mass spectrometry method. For elucidating intestinal transport mechanism, the cells were incubated with or without transport inhibitors, energy source, or a metabolic inhibitor. Phloridzin and verapamil as inhibitors of sodium glucose transport protein (SGLT1) and P-glycoprotein, respectively, were not responsible for cellular uptake of SMM. Glucose and sodium azide were not affected by the cellular accumulation of SMM. The efflux ratio of SMM was 0.26, implying that it is not effluxed through Caco-2 cells. The apparent coefficient permeability (P app ) of SMM was 4.69 × 10 -5 cm/s, indicating that it will show good oral absorption in in vivo. © 2016 Institute of Food Technologists®.

MULTIPLICITY OF THE PROTOSTAR SERPENS SMM 1 REVEALED BY MILLIMETER IMAGING

International Nuclear Information System (INIS)

Choi, Minho

2009-01-01

The Serpens SMM 1 region was observed in the 6.9 mm continuum with an angular resolution of about 0.''6. Two sources were found to have steep positive spectra suggesting emission from dust. The stronger one, SMM 1a, is the driving source of the bipolar jet previously known, and the mass of the dense molecular gas traced by the millimeter continuum is about 8 M sun . The newly found source, SMM 1b, positionally coincides with the brightest mid-IR source in this region, which implies that SMM 1b is yet another young stellar object. SMM 1b seems to be less deeply embedded than SMM 1a. SMM 1 is probably a protobinary system with a projected separation of 500 AU.

The nature of strong Brønsted acidity of Ni-SMM clay

NARCIS (Netherlands)

Yue, C.; Liu, C.; Mezari, B.; Brückner, A.; Pidko, E.A.; Rigutto, M.S.; Hensen, E.J.M.

2016-01-01

The origin of the high Brønsted acidity of Ni-SMM (Ni-substituted synthetic mica-montmorillonite; beidellite structure) clays was investigated. Ni-SMM clays with varying F content, SMM with F and Ni-SMM without F in the structure were synthesized under hydrothermal conditions. Ni-SMM clays with

Comparison of residual stress measurement in thin films using surface micromachining method

International Nuclear Information System (INIS)

He, Q.; Luo, Z.X.; Chen, X.Y.

2008-01-01

Conductive, dielectric, semiconducting, piezoelectric and ferroelectric thin films are extensively used for MEMS/NEMS applications. One of the important parameters of thin films is residual stress. The residual stress can seriously affect the properties, performance and long-term stability of the films. Excessive compressive or tensile stress results in buckling, cracking, splintering and sticking problems. Stress measurement techniques are therefore essential for both process development and process monitoring. Many suggestions for stress measurement in thin films have been made over the past several decades. This paper is concentrated on the in situ stress measurement using surface micromachining techniques to determine the residual stress. The authors review and compare several types of stress measurement methods including buckling technique, rotating technique, micro strain gauge and long-short beam strain sensor

Vascular tissue engineering by computer-aided laser micromachining.

Science.gov (United States)

Doraiswamy, Anand; Narayan, Roger J

2010-04-28

Many conventional technologies for fabricating tissue engineering scaffolds are not suitable for fabricating scaffolds with patient-specific attributes. For example, many conventional technologies for fabricating tissue engineering scaffolds do not provide control over overall scaffold geometry or over cell position within the scaffold. In this study, the use of computer-aided laser micromachining to create scaffolds for vascular tissue networks was investigated. Computer-aided laser micromachining was used to construct patterned surfaces in agarose or in silicon, which were used for differential adherence and growth of cells into vascular tissue networks. Concentric three-ring structures were fabricated on agarose hydrogel substrates, in which the inner ring contained human aortic endothelial cells, the middle ring contained HA587 human elastin and the outer ring contained human aortic vascular smooth muscle cells. Basement membrane matrix containing vascular endothelial growth factor and heparin was to promote proliferation of human aortic endothelial cells within the vascular tissue networks. Computer-aided laser micromachining provides a unique approach to fabricate small-diameter blood vessels for bypass surgery as well as other artificial tissues with complex geometries.

SMM coronagraph observations of particulate contamination

Science.gov (United States)

St. Cyr, O. C.; Warner, T.

1991-01-01

Some recent images taken by the white light coronagraph telescope aboard the Solar Maximum Mission (SMM) observatory show bright streaks that are apparently caused by particles associated with the spacecraft. In this report we describe these observations, and we analyze the times of their occurrence. We demonstrate that the sightings occur most often near SMM's orbital dawn, and we speculate that thermal shock is the mechanism that produces the particles. Although these sightings have not seriously affected the coronagraph's scientific operations, the unexpected passage of bright material through the field of view of sensitive spaceborne telescopes can lead to data loss or, in some cases, serious detector damage. The topic of space debris has become a significant concern for designers of both manned and unmanned orbiting platforms. The returned samples from the SMM spacecraft and the observations reported here provide a baseline of experience for future orbital platforms that plan long duration missions.

SMM Observations of Saturn

Science.gov (United States)

Schnopper, Herbert; Mushotzky, Richard (Technical Monitor)

2001-01-01

During the past year I have participated in a series of team telecons to I plan our observation of Saturn with SMM. The observation, scheduled for this month (September), was canceled and a new observation is being planned for 2002.

Modelling of micromachining of human tooth enamel by erbium laser radiation

Energy Technology Data Exchange (ETDEWEB)

Belikov, A V; Skrypnik, A V; Shatilova, K V [St. Petersburg National Research University of Information Technologies, Mechanics and Optics, St. Petersburg (Russian Federation)

2014-08-31

We consider a 3D cellular model of human tooth enamel and a photomechanical cellular model of enamel ablation by erbium laser radiation, taking into account the structural peculiarities of enamel, energy distribution in the laser beam cross section and attenuation of laser energy in biological tissue. The surface area of the texture in enamel is calculated after its micromachining by erbium laser radiation. The influence of the surface area on the bond strength of enamel with dental filling materials is discussed. A good correlation between the computer simulation of the total work of adhesion and experimentally measured bond strength between the dental filling material and the tooth enamel after its micromachining by means of YAG : Er laser radiation is attained. (laser biophotonics)

Modelling of micromachining of human tooth enamel by erbium laser radiation

International Nuclear Information System (INIS)

Belikov, A V; Skrypnik, A V; Shatilova, K V

2014-01-01

We consider a 3D cellular model of human tooth enamel and a photomechanical cellular model of enamel ablation by erbium laser radiation, taking into account the structural peculiarities of enamel, energy distribution in the laser beam cross section and attenuation of laser energy in biological tissue. The surface area of the texture in enamel is calculated after its micromachining by erbium laser radiation. The influence of the surface area on the bond strength of enamel with dental filling materials is discussed. A good correlation between the computer simulation of the total work of adhesion and experimentally measured bond strength between the dental filling material and the tooth enamel after its micromachining by means of YAG : Er laser radiation is attained. (laser biophotonics)

Analysis and prediction of dimensions and cost of laser micro-machining internal channel fabrication process

Directory of Open Access Journals (Sweden)

Brabazon D.

2010-06-01

Full Text Available This paper presents the utilisation of Response Surface Methodology (RSM as the prediction tool for the laser micro-machining process. Laser internal microchannels machined using pulsed Nd:YVO4 laser in polycarbonate were investigated. The experiments were carried out according to 33 factorial Design of Experiment (DoE. In this work the three input process set as control parameters were laser power, P; pulse repetition frequency, PRF; and sample translation speed, U. Measured responses were the channel width and the micro-machining operating cost per metre of produced microchannels. The responses were sufficiently predicted within the set micro-machining parameters limits. Two factorial interaction (2FI and quadratic polynomial regression equations for both responses were constructed. It is proposed that the developed prediction equations can be used to find locally optimal micro-machining process parameters under experimental and operational conditions.

Advanced technology trend survey of micromachines in Europe; Oshu ni okeru micromachine sentan gijutsu doko chosa

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-02-01

In this research survey, the development trend of micromachine technology in Europe was surveyed, development level of micromachine technology of European companies was grasped, and practical application fields of their target were investigated. Technology development level of private companies in Japan`s national projects and practical application fields of Japan`s target were arranged. Trends of micromachine technology development are compared between Japanese companies and European companies. Among micromachine technology development projects in Europe, ``8520 MUST`` is a part of the ESPRIT Project. About 40,000 companies among about 170,000 companies in whole Europe are relating to the MUST Project. The main fields include the manufacturing technology, process control of machines, technology of safety, sensor technology in environmental fields, and automotive technology. The marketing fields of application include the automobile, military technology, home automation, industrial process, medical technology, environmental technology, and games. The results can be compared with the direction of research and development in Japan. 22 figs., 8 tabs.

Laser Micromachining and Information Discovery Using a Dual Beam Interferometry

Energy Technology Data Exchange (ETDEWEB)

Theppakuttaikomaraswamy, Senthil P. [Iowa State Univ., Ames, IA (United States)

2001-01-01

Lasers have proven to be among the most promising tools for micromachining because they can process features down to the size of the laser wavelength (smaller than 1 micrometer) and they provide a non-contact technology for machining. The demand for incorporating in-situ diagnostics technology into the micromachining environment is driven by the increasing need for producing micro-parts of high quality and accuracy. Laser interferometry can be used as an on-line monitoring tool and it is the aim of this work to enhance the understanding and application of Michelson interferometry principle for the in-situ diagnostics of the machining depth on the sub-micron and micron scales. micromachining is done on two different materials and a comprehensive investigation is done to control the width and depth of the machined feature. To control the width of the feature, laser micromachining is done on copper and a detailed analysis is performed. The objective of this experiment is to make a precision mask for sputtering with an array of holes on it using an Nd:YAG laser of 532 nm wavelength. The diameter of the hole is 50 μm and the spacing between holes (the distance between the centers) is 100 μm. Michelson interferometer is integrated with a laser machining system to control the depth of machining. An excimer laser of 308 nm wavelength is used for micromachining. A He-Ne laser of 632.8 nm wavelength is used as the light source for the interferometer. Interference patterns are created due to the change in the path length between the two interferometer arms. The machined depth information is obtained from the interference patterns on an oscilloscope detected by a photodiode. To compare the predicted depth by the interferometer with the true machining depth, a surface profilometer is used to measure the actual machining depth on the silicon. It is observed that the depths of machining obtained by the surface profile measurement are in accordance with the interferometer

Micromachined tunable metamaterials: a review

International Nuclear Information System (INIS)

Liu, A Q; Zhu, W M; Tsai, D P; Zheludev, N I

2012-01-01

This paper reviews micromachined tunable metamaterials, whereby the tuning capabilities are based on the mechanical reconfiguration of the lattice and/or the metamaterial element geometry. The primary focus of this review is the feasibility of the realization of micromachined tunable metamaterials via structure reconfiguration and the current state of the art in the fabrication technologies of structurally reconfigurable metamaterial elements. The micromachined reconfigurable microstructures not only offer a new tuning method for metamaterials without being limited by the nonlinearity of constituent materials, but also enable a new paradigm of reconfigurable metamaterial-based devices with mechanical actuations. With recent development in nanomachining technology, it is possible to develop structurally reconfigurable metamaterials with faster tuning speed, higher density of integration and more flexible choice of the working frequencies. (review article)

Physics-based signal processing algorithms for micromachined cantilever arrays

Science.gov (United States)

Candy, James V; Clague, David S; Lee, Christopher L; Rudd, Robert E; Burnham, Alan K; Tringe, Joseph W

2013-11-19

A method of using physics-based signal processing algorithms for micromachined cantilever arrays. The methods utilize deflection of a micromachined cantilever that represents the chemical, biological, or physical element being detected. One embodiment of the method comprises the steps of modeling the deflection of the micromachined cantilever producing a deflection model, sensing the deflection of the micromachined cantilever and producing a signal representing the deflection, and comparing the signal representing the deflection with the deflection model.

Silicon micromachined vibrating gyroscopes

Science.gov (United States)

Voss, Ralf

1997-09-01

This work gives an overview of silicon micromachined vibrating gyroscopes. Market perspectives and fields of application are pointed out. The advantage of using silicon micromachining is discussed and estimations of the desired performance, especially for automobiles are given. The general principle of vibrating gyroscopes is explained. Vibrating silicon gyroscopes can be divided into seven classes. for each class the characteristic principle is presented and examples are given. Finally a specific sensor, based on a tuning fork for automotive applications with a sensitivity of 250(mu) V/degrees is described in detail.

Techniques for SMM/THz Chemical Analysis: Investigations and Exploitation of the Large Molecule Limit

Science.gov (United States)

2014-03-03

SECURITY CLASSIFICATION OF: It has long been recognized that the SMM /THz has a unique combinations of attributes that make it attractive as a basis for...applicability of SMM chemical sensors; the second is to explore infrared – SMM double resonance as a basis for atmospheric remote sensing; and the third...2014 12-Aug-2009 11-Aug-2013 Approved for Public Release; Distribution Unlimited Techniques for SMM /THz Chemical Analysis: Investigations and

Preclinical evaluation of SMM-189, a cannabinoid receptor 2-specific inverse agonist.

Science.gov (United States)

Presley, Chaela; Abidi, Ammaar; Suryawanshi, Satyendra; Mustafa, Suni; Meibohm, Bernd; Moore, Bob M

2015-08-01

Cannabinoid receptor 2 agonists and inverse agonists are emerging as new therapeutic options for a spectrum of autoimmune-related disease. Of particular interest, is the ability of CB2 ligands to regulate microglia function in neurodegenerative diseases and traumatic brain injury. We have previously reported the receptor affinity of 3',5'-dichloro-2,6-dihydroxy-biphenyl-4-yl)-phenyl-methanone (SMM-189) and the characterization of the beneficial effects of SMM-189 in the mouse model of mild traumatic brain injury. Herein, we report the further characterization of SMM-189 as a potent and selective CB2 inverse agonist, which acts as a noncompetitive inhibitor of CP 55,940. The ability of SMM-189 to regulate microglial activation, in terms of chemokine expression and cell morphology, has been determined. Finally, we have determined that SMM-189 possesses acceptable biopharmaceutical properties indicating that the triaryl class of CB2 inverse agonists are viable compounds for continued preclinical development for the treatment of neurodegenerative disorders and traumatic brain injury.

Optical wireless communications for micromachines

Science.gov (United States)

O'Brien, Dominic C.; Yuan, Wei Wen; Liu, Jing Jing; Faulkner, Grahame E.; Elston, Steve J.; Collins, Steve; Parry-Jones, Lesley A.

2006-08-01

A key challenge for wireless sensor networks is minimizing the energy required for network nodes to communicate with each other, and this becomes acute for self-powered devices such as 'smart dust'. Optical communications is a potentially attractive solution for such devices. The University of Oxford is currently involved in a project to build optical wireless links to smart dust. Retro-reflectors combined with liquid crystal modulators can be integrated with the micro-machine to create a low power transceiver. When illuminated from a base station a modulated beam is returned, transmitting data. Data from the base station can be transmitted using modulation of the illuminating beam and a receiver at the micro-machine. In this paper we outline the energy consumption and link budget considerations in the design of such micro-machines, and report preliminary experimental results.

Multiplicity of the Protostar Serpens SMM 1 Revealed by Millimeter Imaging

OpenAIRE

Choi, Minho

2009-01-01

The Serpens SMM 1 region was observed in the 6.9 mm continuum with an angular resolution of about 0.6 arcsec. Two sources were found to have steep positive spectra suggesting emission from dust. The stronger one, SMM 1a, is the driving source of the bipolar jet known previously, and the mass of the dense molecular gas traced by the millimeter continuum is about 8 solar mass. The newly found source, SMM 1b, positionally coincides with the brightest mid-IR source in this region, which implies t...

Sustainable Materials Management (SMM) Web Academy Webinar: EPA's SMM Electronics Challenge - What's in it for you?

Science.gov (United States)

There will be a webinar entitled, EPA’s SMM Electronics Challenge: What’s in it for you?” to hear how the Challenge can help you preserve the environment, demonstrate leadership by building more sustainable electronics.

Sustainable Materials Management (SMM) Electronics Challenge

Science.gov (United States)

Learn how the SMM Electronics Challenge encourage electronic manufacturers to strive to send 100 percent of the used electronics they collect from the public and retailers to certified electronics refurbishers and recyclers.

SMM-system: A mining tool to identify specific markers in Salmonella enterica.

Science.gov (United States)

Yu, Shuijing; Liu, Weibing; Shi, Chunlei; Wang, Dapeng; Dan, Xianlong; Li, Xiao; Shi, Xianming

2011-03-01

This report presents SMM-system, a software package that implements various personalized pre- and post-BLASTN tasks for mining specific markers of microbial pathogens. The main functionalities of SMM-system are summarized as follows: (i) converting multi-FASTA file, (ii) cutting interesting genomic sequence, (iii) automatic high-throughput BLASTN searches, and (iv) screening target sequences. The utility of SMM-system was demonstrated by using it to identify 214 Salmonella enterica-specific protein-coding sequences (CDSs). Eighteen primer pairs were designed based on eighteen S. enterica-specific CDSs, respectively. Seven of these primer pairs were validated with PCR assay, which showed 100% inclusivity for the 101 S. enterica genomes and 100% exclusivity of 30 non-S. enterica genomes. Three specific primer pairs were chosen to develop a multiplex PCR assay, which generated specific amplicons with a size of 180bp (SC1286), 238bp (SC1598) and 405bp (SC4361), respectively. This study demonstrates that SMM-system is a high-throughput specific marker generation tool that can be used to identify genus-, species-, serogroup- and even serovar-specific DNA sequences of microbial pathogens, which has a potential to be applied in food industries, diagnostics and taxonomic studies. SMM-system is freely available and can be downloaded from http://foodsafety.sjtu.edu.cn/SMM-system.html. Copyright © 2011 Elsevier B.V. All rights reserved.

Design and Performance of a Focus-Detection System for Use in Laser Micromachining

Directory of Open Access Journals (Sweden)

Binh Xuan Cao

2016-01-01

Full Text Available We describe a new approach for locating the focal position in laser micromachining. This approach is based on a feedback system that uses a charge-coupled device (CCD camera, a beam splitter, and a mirror to focus a laser beam on the surface of a work piece. We tested the proposed method for locating the focal position by using Zemax simulations, as well as physically carrying out drilling processes. Compared with conventional methods, this approach is advantageous because: the implementation is simple, the specimen can easily be positioned at the focal position, and the dynamically adjustable scan amplitude and the CCD camera can be used to monitor the laser beam’s profile. The proposed technique will be particularly useful for locating the focal position on any surface in laser micromachining.

Micromachining process – current situation and challenges

Directory of Open Access Journals (Sweden)

Lalakiya Meet Rajeshkumar

2015-01-01

Full Text Available The rapid progress in the scientific innovations and the hunt for the renewable energy increases the urge for producing the bio electronic products, solar cells, bio batteries, nano robots, MEMS, blood less surgical tools which can be possible with the aid of the micromachining. This article helps us to understand the evolution and the challenges faced by the micromachining process. Micro machining is an enabling technology that facilitates component miniaturization and improved performance characteristics. Growing demand for less weight, high accuracy, high precision, meagre lead time, reduced batch size, less human interference are the key drivers for the micromachining than the conventional machining process.

Excimer laser micromachining for 3D microstructure

NARCIS (Netherlands)

Choi, Kyung Hyun; Meijer, J.; Masuzawa, Takahisa; Kim, Dae-Hyun

2004-01-01

A new 3D micromachining method, called Hole Area Modulation (HAM), has been introduced to enhance the current micromachining technology. In this method, information on the machining depth is converted to the sizes of holes on the mask. The machining is carried out with a simple 2D movement of the

Sustainable Materials Management (SMM) WasteWise Data

Science.gov (United States)

EPA??s WasteWise encourages organizations and businesses to achieve sustainability in their practices and reduce select industrial wastes. WasteWise is part of EPA??s sustainable materials management efforts, which promote the use and reuse of materials more productively over their entire lifecycles. All U.S. businesses, governments and nonprofit organizations can join WasteWise as a partner, endorser or both. Current participants range from small local governments and nonprofit organizations to large multinational corporations. Partners demonstrate how they reduce waste, practice environmental stewardship and incorporate sustainable materials management into their waste-handling processes. Endorsers promote enrollment in WasteWise as part of a comprehensive approach to help their stakeholders realize the economic benefits to reducing waste. WasteWise helps organizations reduce their impact on global climate change through waste reduction. Every stage of a product's life cycle??extraction, manufacturing, distribution, use and disposal??indirectly or directly contributes to the concentration of greenhouse gases (GHGs) in the atmosphere and affects the global climate. WasteWise is part of EPA's larger SMM program (https://www.epa.gov/smm). Sustainable Materials Management (SMM) is a systemic approach to using and reusing materials more productively over their entire lifecycles. It represents a change in how our society thinks about the use of natural resources

Sustainable Materials Management (SMM) Electronics Challenge Data

Data.gov (United States)

U.S. Environmental Protection Agency — On September 22, 2012, EPA launched the SMM Electronics Challenge. The Challenge encourages electronics manufacturers, brand owners and retailers to strive to send...

Micromachined Precision Inertial Instruments

National Research Council Canada - National Science Library

Najafi, Khalil

2003-01-01

This program focuses on developing inertial-grade micromachined accelerometers and gyroscopes and their associated electronics and packaging for use in a variety of military and commercial applications...

Non-traditional micromachining processes fundamentals and applications

CERN Document Server

Bhattacharyya, B; Davim, J

2017-01-01

This book presents a complete coverage of micromachining processes from their basic material removal phenomena to past and recent research carried by a number of researchers worldwide. Chapters on effective utilization of material resources, improved efficiency, reliability, durability, and cost effectiveness of the products are presented. This book provides the reader with new and recent developments in the field of micromachining and microfabrication of engineering materials.

Resist materials for proton micromachining

International Nuclear Information System (INIS)

Kan, J.A. van; Sanchez, J.L.; Xu, B.; Osipowicz, T.; Watt, F.

1999-01-01

The production of high aspect ratio microstructures is a potential growth area. The combination of deep X-ray lithography with electroforming and micromolding (i.e. LIGA) is one of the main techniques used to produce 3D microstructures. The new technique of proton micromachining employs focused MeV protons in a direct write process which is complementary to LIGA, e.g. micromachining with 2 MeV protons results in microstructures with a height of 63 μm and lateral sub-micrometer resolution in PMMA resist. The aim of this paper is to investigate the capabilities of proton micromachining as a lithographic technique. This involves the study of different types of resists. The dose distribution of high molecular weight PMMA is compared with three other types of resist: First the positive photo resist AZ P4620 will be discussed and then PMGI SF 23, which can be used as a deep UV, e-beam or X-ray resist. Finally SU-8, a new deep UV negative type of chemically amplified resist will be discussed. All these polymers are applied using the spin coating technique at thicknesses of between 1 and 36 μm

Micromachining Lithium Niobate for Rapid Prototyping of Resonant Biosensors

International Nuclear Information System (INIS)

Al-Shibaany, Zeyad Yousif Abdoon; Hedley, John; Huo, Dehong; Hu, Zhongxu

2014-01-01

Lithium niobate material is widely used in MEMS application due to its piezoelectric properties. This paper presents the micromachining process of lithium niobate to rapid prototype a resonant biosensor design. A high precision CNC machine was used to machine a sample of lithium niobate material at 5 different spindle speeds to find out the best conditions to machine this brittle material. A qualitative visual check of the surface was performed by using scanning electron microscopy, surface roughness was quantitatively investigated using an optical surface profiler and Raman spectroscopy to check the strain of the surface. Results show that the surface quality of the lithium niobate was significantly affected by the spindle speed with optimum conditions at 70k rpm giving a strained surface with 500 nm rms roughness

Acceleration sensitivity of micromachined pressure sensors

Science.gov (United States)

August, Richard; Maudie, Theresa; Miller, Todd F.; Thompson, Erik

1999-08-01

Pressure sensors serve a variety of automotive applications, some which may experience high levels of acceleration such as tire pressure monitoring. To design pressure sensors for high acceleration environments it is important to understand their sensitivity to acceleration especially if thick encapsulation layers are used to isolate the device from the hostile environment in which they reside. This paper describes a modeling approach to determine their sensitivity to acceleration that is very general and is applicable to different device designs and configurations. It also describes the results of device testing of a capacitive surface micromachined pressure sensor at constant acceleration levels from 500 to 2000 g's.

Structure optimization and simulation analysis of the quartz micromachined gyroscope

Directory of Open Access Journals (Sweden)

Xuezhong Wu

2014-02-01

Full Text Available Structure optimization and simulation analysis of the quartz micromachined gyroscope are reported in this paper. The relationships between the structure parameters and the frequencies of work mode were analysed by finite element analysis. The structure parameters of the quartz micromachined gyroscope were optimized to reduce the difference between the frequencies of the drive mode and the sense mode. The simulation results were proved by testing the prototype gyroscope, which was fabricated by micro-electromechanical systems (MEMS technology. Therefore, the frequencies of the drive mode and the sense mode can match each other by the structure optimization and simulation analysis of the quartz micromachined gyroscope, which is helpful in the design of the high sensitivity quartz micromachined gyroscope.

Prediction of MHC class II binding affinity using SMM-align, a novel stabilization matrix alignment method.

Science.gov (United States)

Nielsen, Morten; Lundegaard, Claus; Lund, Ole

2007-07-04

Antigen presenting cells (APCs) sample the extra cellular space and present peptides from here to T helper cells, which can be activated if the peptides are of foreign origin. The peptides are presented on the surface of the cells in complex with major histocompatibility class II (MHC II) molecules. Identification of peptides that bind MHC II molecules is thus a key step in rational vaccine design and developing methods for accurate prediction of the peptide:MHC interactions play a central role in epitope discovery. The MHC class II binding groove is open at both ends making the correct alignment of a peptide in the binding groove a crucial part of identifying the core of an MHC class II binding motif. Here, we present a novel stabilization matrix alignment method, SMM-align, that allows for direct prediction of peptide:MHC binding affinities. The predictive performance of the method is validated on a large MHC class II benchmark data set covering 14 HLA-DR (human MHC) and three mouse H2-IA alleles. The predictive performance of the SMM-align method was demonstrated to be superior to that of the Gibbs sampler, TEPITOPE, SVRMHC, and MHCpred methods. Cross validation between peptide data set obtained from different sources demonstrated that direct incorporation of peptide length potentially results in over-fitting of the binding prediction method. Focusing on amino terminal peptide flanking residues (PFR), we demonstrate a consistent gain in predictive performance by favoring binding registers with a minimum PFR length of two amino acids. Visualizing the binding motif as obtained by the SMM-align and TEPITOPE methods highlights a series of fundamental discrepancies between the two predicted motifs. For the DRB1*1302 allele for instance, the TEPITOPE method favors basic amino acids at most anchor positions, whereas the SMM-align method identifies a preference for hydrophobic or neutral amino acids at the anchors. The SMM-align method was shown to outperform other

Prediction of MHC class II binding affinity using SMM-align, a novel stabilization matrix alignment method

Directory of Open Access Journals (Sweden)

Lund Ole

2007-07-01

Full Text Available Abstract Background Antigen presenting cells (APCs sample the extra cellular space and present peptides from here to T helper cells, which can be activated if the peptides are of foreign origin. The peptides are presented on the surface of the cells in complex with major histocompatibility class II (MHC II molecules. Identification of peptides that bind MHC II molecules is thus a key step in rational vaccine design and developing methods for accurate prediction of the peptide:MHC interactions play a central role in epitope discovery. The MHC class II binding groove is open at both ends making the correct alignment of a peptide in the binding groove a crucial part of identifying the core of an MHC class II binding motif. Here, we present a novel stabilization matrix alignment method, SMM-align, that allows for direct prediction of peptide:MHC binding affinities. The predictive performance of the method is validated on a large MHC class II benchmark data set covering 14 HLA-DR (human MHC and three mouse H2-IA alleles. Results The predictive performance of the SMM-align method was demonstrated to be superior to that of the Gibbs sampler, TEPITOPE, SVRMHC, and MHCpred methods. Cross validation between peptide data set obtained from different sources demonstrated that direct incorporation of peptide length potentially results in over-fitting of the binding prediction method. Focusing on amino terminal peptide flanking residues (PFR, we demonstrate a consistent gain in predictive performance by favoring binding registers with a minimum PFR length of two amino acids. Visualizing the binding motif as obtained by the SMM-align and TEPITOPE methods highlights a series of fundamental discrepancies between the two predicted motifs. For the DRB1*1302 allele for instance, the TEPITOPE method favors basic amino acids at most anchor positions, whereas the SMM-align method identifies a preference for hydrophobic or neutral amino acids at the anchors. Conclusion

Cryogenically assisted abrasive jet micromachining of polymers

International Nuclear Information System (INIS)

Getu, H; Papini, M; Spelt, J K

2008-01-01

The abrasive jet micromachining (AJM) of elastomers and polymers such as polydimethylsiloxane (PDMS), acrylonitrile butadiene styrene (ABS) and polytetrafluoroethylene (PTFE) for use in micro-fluidic devices was found to be very slow or impossible at room temperature. To enhance the material removal rate in such materials, a stream of liquid nitrogen (LN 2 ) was injected into the abrasive jet, cooling the target to cryogenic temperatures. Erosion rate measurements on the three polymeric materials (PDMS, ABS and PTFE) with and without the use of LN 2 were compared along with the profiles of micromachined channels and holes. It was found that the use of LN 2 cooling caused brittle erosion in PDMS, allowing it to be micromachined successfully. An erosion rate increase was also observed in PTFE and ABS at high and intermediate impact angles. The use of LN 2 also was found to reduce particle embedding

Micromachining with copper lasers

Science.gov (United States)

Knowles, Martyn R. H.; Bell, Andy; Foster-Turner, Gideon; Rutterford, Graham; Chudzicki, J.; Kearsley, Andrew J.

1997-04-01

In recent years the copper laser has undergone extensive development and has emerged as a leading and unique laser for micromachining. The copper laser is a high average power (10 - 250 W), high pulse repetition rate (2 - 32 kHz), visible laser (511 nm and 578 nm) that produces high peak power (typically 200 kW), short pulses (30 ns) and very good beam quality (diffraction limited). This unique set of laser parameters results in exceptional micro-machining in a wide variety of materials. Typical examples of the capabilities of the copper laser include the drilling of small holes (10 - 200 micrometer diameter) in materials as diverse as steel, ceramic, diamond and polyimide with micron precision and low taper (less than 1 degree) cutting and profiling of diamond. Application of the copper laser covers the electronic, aerospace, automotive, nuclear, medical and precision engineering industries.

Fiscal 1996 report on technological results. R and D on micromachine technology; 1996 nendo micromachine gijutsu no kenkyu kaihatsu seika hokokusho

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-03-01

Researches on basic element technology of micromachines are conducted that operate autonomously in a narrow small part in a complicated apparatus or in vivo. The areas of activity are (1) research on micromachine systems, (2) a subminiature liquid synthesizing system, and (3) comprehensive investigation and research. In (1), the researches were carried out on the miniaturization and functional combination of a micro laser catheter and a micro tactile sensor catheter, which are the primary components of a coeliac diagnostic and therapeutic system, a 'micro catheter for cerebral blood vessel/treatment', as a micromachine system in the medical field. In (2), R and D was conducted on a system element technology assuming it contributed to a subminiature liquid synthesizing system capable of preparing various liquids including pharmaceuticals accurately with a trace amount. In (3), examination was made on the application area of a micromachine system with priority given to a medical field and also on technological subjects to be tapped, as well as on the contents of (2), with a device installed for evaluating the operating characteristic of a distribution type fluid actuator as needed for the development. (NEDO)

Sustainable Materials Management (SMM) Federal Green Challenge (FGC) Data

Data.gov (United States)

U.S. Environmental Protection Agency — The Federal Green Challenge (FGC) is a national effort under EPA's Sustainable Materials Management (SMM) Program, challenging EPA and other federal agencies...

Real-time control of ultrafast laser micromachining by laser-induced breakdown spectroscopy

International Nuclear Information System (INIS)

Tong Tao; Li Jinggao; Longtin, Jon P.

2004-01-01

Ultrafast laser micromachining provides many advantages for precision micromachining. One challenging problem, however, particularly for multilayer and heterogeneous materials, is how to prevent a given material from being ablated, as ultrafast laser micromachining is generally material insensitive. We present a real-time feedback control system for an ultrafast laser micromachining system based on laser-induced breakdown spectroscopy (LIBS). The characteristics of ultrafast LIBS are reviewed and discussed so as to demonstrate the feasibility of the technique. Comparison methods to identify the material emission patterns are developed, and several of the resulting algorithms were implemented into a real-time computer control system. LIBS-controlled micromachining is demonstrated for the fabrication of microheater structures on thermal sprayed materials. Compared with a strictly passive machining process without any such feedback control, the LIBS-based system provides several advantages including less damage to the substrate layer, reduced machining time, and more-uniform machining features

Direct writing of microtunnels using proton beam micromachining

International Nuclear Information System (INIS)

Marot, Laurent; Munnik, Frans; Mikhailov, Serguei

2006-01-01

The production of high aspect ratio microstructures is a potential growth area. The combination of deep X-ray lithography with electroforming and micromolding (i.e. LIGA) is one of the main techniques used to produce 3D microstructures. The new technique of proton micromachining employs focused MeV protons in a direct write process which is complementary to LIGA. During ion exposure of positive photoresist like PMMA, scission of molecular chains occurs. These degraded polymer chains are removed by the developer. The aim of this paper is to investigate the capabilities of proton micromachining as a lithographic technique. We show the realization of sub-surface channels, or microtunnels, which have been fabricated in only one exposure and without cutting or resurfacing the material. Using our Van-de-Graaff accelerator, the resist (PMMA) has been exposed with high-energy protons (2.5 MeV). The range of charged particles in matter is well-defined and depends on the energy. Therefore, it is possible to obtain a dose which is sufficient to develop the bottom part of the ion paths but not the top part. Thus, by selecting the energy and the exposure time, a big variety of microtunnels can be realized

Silicon-micromachined microchannel plates

International Nuclear Information System (INIS)

Beetz, Charles P.; Boerstler, Robert; Steinbeck, John; Lemieux, Bryan; Winn, David R.

2000-01-01

Microchannel plates (MCP) fabricated from standard silicon wafer substrates using a novel silicon micromachining process, together with standard silicon photolithographic process steps, are described. The resulting SiMCP microchannels have dimensions of ∼0.5 to ∼25 μm, with aspect ratios up to 300, and have the dimensional precision and absence of interstitial defects characteristic of photolithographic processing, compatible with positional matching to silicon electronics readouts. The open channel areal fraction and detection efficiency may exceed 90% on plates up to 300 mm in diameter. The resulting silicon substrates can be converted entirely to amorphous quartz (qMCP). The strip resistance and secondary emission are developed by controlled depositions of thin films, at temperatures up to 1200 deg. C, also compatible with high-temperature brazing, and can be essentially hydrogen, water and radionuclide-free. Novel secondary emitters and cesiated photocathodes can be high-temperature deposited or nucleated in the channels or the first strike surface. Results on resistivity, secondary emission and gain are presented

Micromachined thin-film sensors for SOI-CMOS co-integration

CERN Document Server

Laconte, Jean; Raskin, Jean-Pierre

2006-01-01

Co-integration of MEMS and MOS in SOI technology is promising and well demonstrated hereThe impact of Micromachining on SOI devices is deeply analyzed for the first timeInclude extensive TMAH etching, residual stress, microheaters, gas-flow sensors reviewResidual stresses in thin films need to be more and more monitored in MEMS designsTMAH micromachining is an attractive alternative to KOH.

A silicon micromachined resonant pressure sensor

International Nuclear Information System (INIS)

Tang Zhangyang; Fan Shangchun; Cai Chenguang

2009-01-01

This paper describes the design, fabrication and test of a silicon micromachined resonant pressure sensor. A square membrane and a doubly clamped resonant beam constitute a compound structure. The former senses the pressure directly, while the latter changes its resonant frequency according to deformation of the membrane. The final output relation between the resonant frequency and the applied pressure is deducted according to the structure mechanical properties. Sensors are fabricated by micromachining technology, and then sealed in vaccum. These sensors are tested by open-loop and close-loop system designed on purpose. The experiment results demonstrate that the sensor has a sensitivity of 49.8Hz/kPa and repeatability of 0.08%.

Unveiling the wet chemical etching characteristics of polydimethylsiloxane film for soft micromachining applications

International Nuclear Information System (INIS)

Kakati, A; Maji, D; Das, S

2017-01-01

Micromachining of a polydimethylsiloxane (PDMS) microstructure by wet chemical etching is explored for microelectromechanical systems (MEMS) and microfluidic applications. A 100 µ m thick PDMS film was patterned with different microstructure designs by wet chemical etching using a N-methyl-2-pyrrolidone (C 16 H 36 FN) and tetra-n-butylammonium fluoride (C 5 H 9 NO) mixture solution with 3:1 volume ratio after lithography for studying etching characteristics. The patterning parameters, such as etch rate, surface roughness, pH of etchant solution with time, were thoroughly investigated. A detailed study of surface morphology with etching time revealed nonlinear behaviour of the PDMS surface roughness and etch rate. A maximum rate of 1.45 µ m min −1 for 10 min etching with surface roughness of 360 nm was achieved. A new approach of wet chemical etching with pH controlled doped etchant was introduced for lower surface roughness of etched microstructures, and a constant etch rate during etching. Variation of the etching rate and surface roughness by pH controlled etching was performed by doping 5–15 gm l −1 of silicic acid (SiO 2xH2 O) into the traditional etchant solution. PDMS etching by silicic acid doped etchant solution showed a reduction in surface roughness from 400 nm to 220 nm for the same 15 µ m etching. This study is beneficial for micromachining of various MEMS and microfluidic structures such as micropillars, microchannels, and other PDMS microstructures. (paper)

Demonstration of robust micromachined jet technology and its application to realistic flow control problems

International Nuclear Information System (INIS)

Chang, Sung Pil

2006-01-01

This paper describes the demonstration of successful fabrication and initial characterization of micromachined pressure sensors and micromachined jets (microjets) fabricated for use in macro flow control and other applications. In this work, the microfabrication technology was investigated to create a micromachined fluidic control system with a goal of application in practical fluids problems, such as UAV (Unmanned Aerial Vehicle)-scale aerodynamic control. Approaches of this work include : (1) the development of suitable micromachined synthetic jets (microjets) as actuators, which obviate the need to physically extend micromachined structures into an external flow ; and (2) a non-silicon alternative micromachining fabrication technology based on metallic substrates and lamination (in addition to traditional MEMS technologies) which will allow the realization of larger scale, more robust structures and larger array active areas for fluidic systems. As an initial study, an array of MEMS pressure sensors and an array of MEMS modulators for orifice-based control of microjets have been fabricated, and characterized. Both pressure sensors and modulators have been built using stainless steel as a substrate and a combination of lamination and traditional micromachining processes as fabrication technologies

Demonstration of robust micromachined jet technology and its application to realistic flow control problems

Energy Technology Data Exchange (ETDEWEB)

Chang, Sung Pil [Inha University, Incheon (Korea, Republic of)

2006-04-15

This paper describes the demonstration of successful fabrication and initial characterization of micromachined pressure sensors and micromachined jets (microjets) fabricated for use in macro flow control and other applications. In this work, the microfabrication technology was investigated to create a micromachined fluidic control system with a goal of application in practical fluids problems, such as UAV (Unmanned Aerial Vehicle)-scale aerodynamic control. Approaches of this work include : (1) the development of suitable micromachined synthetic jets (microjets) as actuators, which obviate the need to physically extend micromachined structures into an external flow ; and (2) a non-silicon alternative micromachining fabrication technology based on metallic substrates and lamination (in addition to traditional MEMS technologies) which will allow the realization of larger scale, more robust structures and larger array active areas for fluidic systems. As an initial study, an array of MEMS pressure sensors and an array of MEMS modulators for orifice-based control of microjets have been fabricated, and characterized. Both pressure sensors and modulators have been built using stainless steel as a substrate and a combination of lamination and traditional micromachining processes as fabrication technologies.

Micro-machined resonator oscillator

Science.gov (United States)

Koehler, Dale R.; Sniegowski, Jeffry J.; Bivens, Hugh M.; Wessendorf, Kurt O.

1994-01-01

A micro-miniature resonator-oscillator is disclosed. Due to the miniaturization of the resonator-oscillator, oscillation frequencies of one MHz and higher are utilized. A thickness-mode quartz resonator housed in a micro-machined silicon package and operated as a "telemetered sensor beacon" that is, a digital, self-powered, remote, parameter measuring-transmitter in the FM-band. The resonator design uses trapped energy principles and temperature dependence methodology through crystal orientation control, with operation in the 20-100 MHz range. High volume batch-processing manufacturing is utilized, with package and resonator assembly at the wafer level. Unique design features include squeeze-film damping for robust vibration and shock performance, capacitive coupling through micro-machined diaphragms allowing resonator excitation at the package exterior, circuit integration and extremely small (0.1 in. square) dimensioning. A family of micro-miniature sensor beacons is also disclosed with widespread applications as bio-medical sensors, vehicle status monitors and high-volume animal identification and health sensors. The sensor family allows measurement of temperatures, chemicals, acceleration and pressure. A microphone and clock realization is also available.

The micromachined logo of Atomki

International Nuclear Information System (INIS)

Rajta, I.; Szilasi, S.Z.

2006-01-01

Complete text of publication follows. Proton Beam Micromachining, also known as P-beam Writing, is a direct write 3- dimensional lithographic technique. Conventional resist types are PMMA (polymethylmethacrylate), and SU-8 (of MicroChem Corp.); they are positive and negative resists, respectively. In this work we used SU-8, the most common negative resist material. SU-8 was spun on a flat surface, typically Silicon or glass. A direct write proton beam was scanned over an arbitary structure (the Atomki logo can be replaced by any other structure), which produces chain scissioning in the polymer. Post exposure bake (PEB) is usually needed in case of conventional optical lithography, but using protons this bake is done in situ as the ions heat up the sample in vacuum. Subsequently chemical etching takes place, the solvent is available at MicroChem Corp. The schematic diagram of the above described micromachining process is shown on Fig. 1. The irradiation requires a scanning proton microbeam system equipped with suitable beam scanning and blanking facilities. This is available in the Institute, our setup has been upgraded from doublet to triplet focusing system (Oxford Microbeams Ltd.). For scanning we use a DIO card (PCI-6731 of National Instruments), and the IonScan software [1]. Sample preparation was carried out at our 'semi clean' room. This is also where chemical development of the samples and the optical microscopy have been done too. A Zeiss Axio Imager microscope is available (equipped with 5 objective lenses, 4 different contrast methods, transmitted or reflected light illumination). Fig. 2. shows a typical example of the Atomki logo. This is a bright field image, a number of different nice and colourful images can be produced with the other contrast techniques (for more images see the Institute website: http://www.atomki.hu/ ). (author)

Experimental and Modeling Study of Liquid-Assisted—Laser Beam Micromachining of Smart Ceramic Materials

Directory of Open Access Journals (Sweden)

Mayur Parmar

2018-05-01

Full Text Available Smart ceramic materials are next generation materials with the inherent intelligence to adapt to change in the external environment. These materials are destined to play an essential role in several critical engineering applications. Machining these materials using traditional machining processes is a challenge. The laser beam micromachining (LBMM process has the potential to machine such smart materials. However, laser machining when performed in air induces high thermal stress on the surface, often leading to crack formation, recast and re-deposition of ablated material, and large heat-affected zones (HAZ. Performing laser beam machining in the presence of a liquid medium could potentially resolve these issues. This research investigates the possibility of using a Liquid Assisted—Laser Beam Micromachining (LA-LBMM process for micromachining smart ceramic materials. Experimental studies are performed to compare the machining quality of laser beam machining process in air and in a liquid medium. The study reveals that the presence of liquid medium helps in controlling the heat-affected zone and the taper angle of the cavity drilled, thereby enhancing the machining quality. Analytical modeling is developed for the prediction of HAZ and cavity diameter both in air and underwater conditions, and the model is capable of predicting the experimental results to within 10% error.

Studying the mechanism of micromachining by short pulsed laser

Science.gov (United States)

Gadag, Shiva

The semiconductor materials like Si and the transparent dielectric materials like glass and quartz are extensively used in optoelectronics, microelectronics, and microelectromechanical systems (MEMS) industries. The combination of these materials often go hand in hand for applications in MEMS such as in chips for pressure sensors, charge coupled devices (CCD), and photovoltaic (PV) cells for solar energy generation. The transparent negative terminal of the solar cell is made of glass on one surface of the PV cell. The positive terminal (cathode) on the other surface of the solar cell is made of silicon with a glass negative terminal (anode). The digital watches and cell phones, LEDs, micro-lens, optical components, and laser optics are other examples for the application of silicon and or glass. The Si and quartz are materials extensively used in CCD and LED for digital cameras and CD players respectively. Hence, three materials: (1) a semiconductor silicon and transparent dielectrics,- (2) glass, and (3) quartz are chosen for laser micromachining as they have wide spread applications in microelectronics industry. The Q-switched, nanosecond pulsed lasers are most extensively used for micro-machining. The nanosecond type of short pulsed laser is less expensive for the end users than the second type, pico or femto, ultra-short pulsed lasers. The majority of the research work done on these materials (Si, SiO 2, and glass) is based on the ultra-short pulsed lasers. This is because of the cut quality, pin point precision of the drilled holes, formation of the nanometer size microstructures and fine features, and minimally invasive heat affected zone. However, there are many applications such as large surface area dicing, cutting, surface cleaning of Si wafers by ablation, and drilling of relatively large-sized holes where some associated heat affected zone due to melting can be tolerated. In such applications the nanosecond pulsed laser ablation of materials is very

Micromachined capacitive ultrasonic immersion transducer array

Science.gov (United States)

Jin, Xuecheng

Capacitive micromachined ultrasonic transducers (cMUTs) have emerged as an attractive alternative to conventional piezoelectric ultrasonic transducers. They offer performance advantages of wide bandwidth and sensitivity that have heretofore been attainable. In addition, micromachining technology, which has benefited from the fast-growing microelectronics industry, enables cMUT array fabrication and electronics integration. This thesis describes the design and fabrication of micromachined capacitive ultrasonic immersion transducer arrays. The basic transducer electrical equivalent circuit is derived from Mason's theory. The effects of Lamb waves and Stoneley waves on cross coupling and acoustic losses are discussed. Electrical parasitics such as series resistance and shunt capacitance are also included in the model of the transducer. Transducer fabrication technology is systematically studied. Device dimension control in both vertical and horizontal directions, process alternatives and variations in membrane formation, via etch and cavity sealing, and metalization as well as their impact on transducer performance are summarized. Both 64 and 128 element 1-D array transducers are fabricated. Transducers are characterized in terms of electrical input impedance, bandwidth, sensitivity, dynamic range, impulse response and angular response, and their performance is compared with theoretical simulation. Various schemes for cross coupling reduction is analyzed, implemented, and verified with both experiments and theory. Preliminary results of immersion imaging are presented using 64 elements 1-D array transducers for active source imaging.

Influence of micromachined targets on laser accelerated proton beam profiles

Science.gov (United States)

Dalui, Malay; Permogorov, Alexander; Pahl, Hannes; Persson, Anders; Wahlström, Claes-Göran

2018-03-01

High intensity laser-driven proton acceleration from micromachined targets is studied experimentally in the target-normal-sheath-acceleration regime. Conical pits are created on the front surface of flat aluminium foils of initial thickness 12.5 and 3 μm using series of low energy pulses (0.5-2.5 μJ). Proton acceleration from such micromachined targets is compared with flat foils of equivalent thickness at a laser intensity of 7 × 1019 W cm-2. The maximum proton energy obtained from targets machined from 12.5 μm thick foils is found to be slightly lower than that of flat foils of equivalent remaining thickness, and the angular divergence of the proton beam is observed to increase as the depth of the pit approaches the foil thickness. Targets machined from 3 μm thick foils, on the other hand, show evidence of increasing the maximum proton energy when the depths of the structures are small. Furthermore, shallow pits on 3 μm thick foils are found to be efficient in reducing the proton beam divergence by a factor of up to three compared to that obtained from flat foils, while maintaining the maximum proton energy.

Surface Soil Moisture Memory Estimated from Models and SMAP Observations

Science.gov (United States)

He, Q.; Mccoll, K. A.; Li, C.; Lu, H.; Akbar, R.; Pan, M.; Entekhabi, D.

2017-12-01

Soil moisture memory(SMM), which is loosely defined as the time taken by soil to forget an anomaly, has been proved to be important in land-atmosphere interaction. There are many metrics to calculate the SMM timescale, for example, the timescale based on the time-series autocorrelation, the timescale ignoring the soil moisture time series and the timescale which only considers soil moisture increment. Recently, a new timescale based on `Water Cycle Fraction' (Kaighin et al., 2017), in which the impact of precipitation on soil moisture memory is considered, has been put up but not been fully evaluated in global. In this study, we compared the surface SMM derived from SMAP observations with that from land surface model simulations (i.e., the SMAP Nature Run (NR) provided by the Goddard Earth Observing System, version 5) (Rolf et al., 2014). Three timescale metrics were used to quantify the surface SMM as: T0 based on the soil moisture time series autocorrelation, deT0 based on the detrending soil moisture time series autocorrelation, and tHalf based on the Water Cycle Fraction. The comparisons indicate that: (1) there are big gaps between the T0 derived from SMAP and that from NR (2) the gaps get small for deT0 case, in which the seasonality of surface soil moisture was removed with a moving average filter; (3) the tHalf estimated from SMAP is much closer to that from NR. The results demonstrate that surface SMM can vary dramatically among different metrics, while the memory derived from land surface model differs from the one from SMAP observation. tHalf, with considering the impact of precipitation, may be a good choice to quantify surface SMM and have high potential in studies related to land atmosphere interactions. References McColl. K.A., S.H. Alemohammad, R. Akbar, A.G. Konings, S. Yueh, D. Entekhabi. The Global Distribution and Dynamics of Surface Soil Moisture, Nature Geoscience, 2017 Reichle. R., L. Qing, D.L. Gabrielle, A. Joe. The "SMAP_Nature_v03" Data

Micromachined Ultrasonic Transducers for 3-D Imaging

DEFF Research Database (Denmark)

Christiansen, Thomas Lehrmann

of state-of-the-art 3-D ultrasound systems. The focus is on row-column addressed transducer arrays. This previously sparsely investigated addressing scheme offers a highly reduced number of transducer elements, resulting in reduced transducer manufacturing costs and data processing. To produce...... such transducer arrays, capacitive micromachined ultrasonic transducer (CMUT) technology is chosen for this project. Properties such as high bandwidth and high design flexibility makes this an attractive transducer technology, which is under continuous development in the research community. A theoretical...... treatment of CMUTs is presented, including investigations of the anisotropic plate behaviour and modal radiation patterns of such devices. Several new CMUT fabrication approaches are developed and investigated in terms of oxide quality and surface protrusions, culminating in a simple four-mask process...

Lyman alpha SMM/UVSP absolute calibration and geocoronal correction

Science.gov (United States)

Fontenla, Juan M.; Reichmann, Edwin J.

1987-01-01

Lyman alpha observations from the Ultraviolet Spectrometer Polarimeter (UVSP) instrument of the Solar Maximum Mission (SMM) spacecraft were analyzed and provide instrumental calibration details. Specific values of the instrument quantum efficiency, Lyman alpha absolute intensity, and correction for geocoronal absorption are presented.

Irradiance Observations of SMM, Spacelab 1, UARS, and ATLAS Experiments

Science.gov (United States)

Willson, Richard

1994-01-01

Detection of intrinsic solar variability on the total flux level was made using results from the first active Radiometer Irradiance Monitor (ACRIM) experiment, launched on the Solar Maximum Mission (SMM)in early 1980.

Laser micromachining of sputtered DLC films

International Nuclear Information System (INIS)

Fu, Y.Q.; Luo, J.K.; Flewitt, A.J.; Ong, S.E.; Zhang, S.; Milne, W.I.

2006-01-01

DLC films with different thicknesses (from 100 nm to 1.9 μm) were deposited using sputtering of graphite target in pure argon atmosphere without substrate heating. Film microstructures (sp 2 /sp 3 ratio) and mechanical properties (modulus, hardness, stress) were characterized as a function of film thickness. A thin layer of aluminum about 60 nm was deposited on the DLC film surface. Laser micromachining of Al/DLC layer was performed to form microcantilever structures, which were released using a reactive ion etching system with SF 6 plasma. Due to the intrinsic stress in DLC films and bimorph Al/DLC structure, the microcantilevers bent up with different curvatures. For DLC film of 100 nm thick, the cantilever even formed microtubes. The relationship between the bimorph beam bending and DLC film properties (such as stress, modulus, etc.) were discussed in details

A batch process micromachined thermoelectric energy harvester: fabrication and characterization

International Nuclear Information System (INIS)

Su, J; Goedbloed, M; Van Andel, Y; De Nooijer, M C; Elfrink, R; Wang, Z; Vullers, R J M; Leonov, V

2010-01-01

Micromachined thermopiles are considered as a cost-effective solution for energy harvesters working at a small temperature difference and weak heat flows typical for, e.g., the human body. They can be used for powering autonomous wireless sensor nodes in a body area network. In this paper, a micromachined thermoelectric energy harvester with 6 µm high polycrystalline silicon germanium (poly-SiGe) thermocouples fabricated on a 6 inch wafer is presented. An open circuit voltage of 1.49 V and an output power of 0.4 µW can be generated with 3.5 K temperature difference in a model of a wearable micromachined energy harvester of the discussed design, which has a die size of 1.0 mm × 2.5 mm inside a watch-size generator

Micromachined Integrated Transducers for Ultrasound Imaging

DEFF Research Database (Denmark)

la Cour, Mette Funding

The purpose of this project is to develop capacitive micromachined ultrasonic transducers (CMUTs) for medical imaging. Medical ultrasound transducers used today are fabricated using piezoelectric materials and bulk processing. To fabricate transducers capable of delivering a higher imaging...

Monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM): novel biological insights and development of early treatment strategies.

Science.gov (United States)

Korde, Neha; Kristinsson, Sigurdur Y; Landgren, Ola

2011-05-26

Monoclonal gammopathy of unknown significance (MGUS) and smoldering multiple myeloma (SMM) are asymptomatic plasma cell dyscrasias, with a propensity to progress to symptomatic MM. In recent years there have been improvements in risk stratification models (involving molecular markers) of both disorders, which have led to better understanding of the biology and probability of progression of MGUS and SMM. In the context of numerous molecular events and heterogeneous risk of progression, developing individualized risk profiles for patients with MGUS and SMM represents an ongoing challenge that has to be addressed by prospective clinical monitoring and extensive correlative science. In this review we discuss the current standard of care of patients with MGUS and SMM, the use of risk models, including flow cytometry and free-light chain analyses, for predicting risk of progression. Emerging evidence from molecular studies on MGUS and SMM, involving cytogenetics, gene-expression profiling, and microRNA as well as molecular imaging is described. Finally, future directions for improving individualized management of MGUS and SMM patients, as well as the potential for developing early treatment strategies designed to delay and prevent development of MM are discussed.

Comparison of backgrounds in OSO-7 and SMM spectrometers and short-term activation in SMM

Science.gov (United States)

Dunphy, P. P.; Forrest, D. J.; Chupp, E. L.; Share, G. H.

1989-01-01

The backgrounds in the OSO-7 Gamma-Ray Monitor and the Solar Maximum Mission Gamma-Ray Spectrometer are compared. After scaling to the same volume, the background spectra agree to within 30 percent. This shows that analyses which successfully describe the background in one detector can be applied to similar detectors of different sizes and on different platforms. The background produced in the SMM spectrometer by a single trapped-radiation belt passage is also studied. This background is found to be dominated by a positron-annihilation line and a continuum spectrum with a high energy cutoff at 5 MeV.

Electron beam micromachining of plastics

Czech Academy of Sciences Publication Activity Database

Dupák, Libor

2014-01-01

Roč. 49, 5-6 (2014), s. 310-314 ISSN 0861-4717 R&D Projects: GA MŠk(CZ) LO1212; GA MŠk ED0017/01/01; GA MŠk EE.2.3.20.0103 Institutional support: RVO:68081731 Keywords : micromachining of plastics * Electron beam Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

Surface-micromachined magnetic undulator with period length between 10μm and 1 mm for advanced light sources

Science.gov (United States)

Harrison, Jere; Joshi, Abhijeet; Lake, Jonathan; Candler, Rob; Musumeci, Pietro

2012-07-01

A technological gap exists between the μm-scale wiggling periods achieved using electromagnetic waves of high intensity laser pulses and the mm scale of permanent-magnet and superconducting undulators. In the sub-mm range, surface-micromachined soft-magnetic micro-electro-mechanical system inductors with integrated solenoidal coils have already experimentally demonstrated 100 to 500 mT field amplitude across air gaps as large as 15μm. Simulations indicate that magnetic fields as large as 1.5 T across 50μm inductor gaps are feasible. A simple rearranging of the yoke and pole geometry allows for fabrication of 10+ cm long undulator structures with period lengths between 12.5μm and 1 mm. Such undulators find application both in high average power spontaneous emission sources and, if used in combination with ultrahigh-brightness electron beams, could lead to the realization of low energy compact free-electron lasers. Challenges include electron energy broadening due to wakefields and Joule heating in the electromagnet.

Switching behavior of double-decker single molecule magnets on a metal surface

Energy Technology Data Exchange (ETDEWEB)

Fu, Yingshuang; Schwoebel, Joerg; Hoffmann, Germar; Brede, Jens; Wiesendanger, Roland [University of Hamburg, Hamburg (Germany); Dillulo, Andrew [Ohio University, Athens (United States); Klyatskaya, Svetlana [Karlsruhe Institute of Technology, Karlsruhe (Germany); Ruben, Mario [Karlsruhe Institute of Technology, Karlsruhe (Germany); Universite de Strasbourg, Strasbourg (France)

2011-07-01

Single molecule magnets (SMM) are most promising materials for spin based molecular electronics. Due to their large magnetic anisotropy stabilized by inside chemical bonds, SMM can potentially be used for information storage at the single molecule level. For applications, it is of importance to adsorb the SMM onto surfaces and to study their subsequent conformational, electronic and magnetic properties. We have investigated the adsorption behavior of Tb and Dy based double-decker SMM on an Ir(111) surface with low temperature scanning tunneling microscopy and spectroscopy. It is found that Tb double-decker molecules bind tightly to the Ir(111) surface. By resonantly injecting tunneling electrons into its LUMO or HOMO state, the Tb double-decker molecule can be switched from a four-lobed structure to an eight-lobed structure. After switching, energy positions of the HOMO and LUMO states both shift closer to the Fermi level. Dy double-decker molecules also exhibit the same switching properties on the Ir(111) surface. The switching behavior of the molecules is tentatively attributed to a conformational change of the double-decker molecular frame.

Demonstration of Robust Micromachined Jet Technology and its Application to Realistic Flow Control Problems

National Research Council Canada - National Science Library

Allen, Mark

2000-01-01

.... Our approaches include: (1) the development of suitable micromachined synthetic jets (microjets) as actuators, which obviate the need to physically extend micromachined structures into an external flow...

Micro benchtop optics by bulk silicon micromachining

Science.gov (United States)

Lee, Abraham P.; Pocha, Michael D.; McConaghy, Charles F.; Deri, Robert J.

2000-01-01

Micromachining of bulk silicon utilizing the parallel etching characteristics of bulk silicon and integrating the parallel etch planes of silicon with silicon wafer bonding and impurity doping, enables the fabrication of on-chip optics with in situ aligned etched grooves for optical fibers, micro-lenses, photodiodes, and laser diodes. Other optical components that can be microfabricated and integrated include semi-transparent beam splitters, micro-optical scanners, pinholes, optical gratings, micro-optical filters, etc. Micromachining of bulk silicon utilizing the parallel etching characteristics thereof can be utilized to develop miniaturization of bio-instrumentation such as wavelength monitoring by fluorescence spectrometers, and other miniaturized optical systems such as Fabry-Perot interferometry for filtering of wavelengths, tunable cavity lasers, micro-holography modules, and wavelength splitters for optical communication systems.

Quantitative sub-surface and non-contact imaging using scanning microwave microscopy

International Nuclear Information System (INIS)

Gramse, Georg; Kasper, Manuel; Hinterdorfer, Peter; Brinciotti, Enrico; Rankl, Christian; Kienberger, Ferry; Lucibello, Andrea; Marcelli, Romolo; Patil, Samadhan B.; Giridharagopal, Rajiv

2015-01-01

The capability of scanning microwave microscopy for calibrated sub-surface and non-contact capacitance imaging of silicon (Si) samples is quantitatively studied at broadband frequencies ranging from 1 to 20 GHz. Calibrated capacitance images of flat Si test samples with varying dopant density (10 15 –10 19 atoms cm −3 ) and covered with dielectric thin films of SiO 2 (100–400 nm thickness) are measured to demonstrate the sensitivity of scanning microwave microscopy (SMM) for sub-surface imaging. Using standard SMM imaging conditions the dopant areas could still be sensed under a 400 nm thick oxide layer. Non-contact SMM imaging in lift-mode and constant height mode is quantitatively demonstrated on a 50 nm thick SiO 2 test pad. The differences between non-contact and contact mode capacitances are studied with respect to the main parameters influencing the imaging contrast, namely the probe tip diameter and the tip–sample distance. Finite element modelling was used to further analyse the influence of the tip radius and the tip–sample distance on the SMM sensitivity. The understanding of how the two key parameters determine the SMM sensitivity and quantitative capacitances represents an important step towards its routine application for non-contact and sub-surface imaging. (paper)

Silicon Micromachined Microlens Array for THz Antennas

Science.gov (United States)

Lee, Choonsup; Chattopadhyay, Goutam; Mehdi, IImran; Gill, John J.; Jung-Kubiak, Cecile D.; Llombart, Nuria

2013-01-01

5 5 silicon microlens array was developed using a silicon micromachining technique for a silicon-based THz antenna array. The feature of the silicon micromachining technique enables one to microfabricate an unlimited number of microlens arrays at one time with good uniformity on a silicon wafer. This technique will resolve one of the key issues in building a THz camera, which is to integrate antennas in a detector array. The conventional approach of building single-pixel receivers and stacking them to form a multi-pixel receiver is not suited at THz because a single-pixel receiver already has difficulty fitting into mass, volume, and power budgets, especially in space applications. In this proposed technique, one has controllability on both diameter and curvature of a silicon microlens. First of all, the diameter of microlens depends on how thick photoresist one could coat and pattern. So far, the diameter of a 6- mm photoresist microlens with 400 m in height has been successfully microfabricated. Based on current researchers experiences, a diameter larger than 1-cm photoresist microlens array would be feasible. In order to control the curvature of the microlens, the following process variables could be used: 1. Amount of photoresist: It determines the curvature of the photoresist microlens. Since the photoresist lens is transferred onto the silicon substrate, it will directly control the curvature of the silicon microlens. 2. Etching selectivity between photoresist and silicon: The photoresist microlens is formed by thermal reflow. In order to transfer the exact photoresist curvature onto silicon, there needs to be etching selectivity of 1:1 between silicon and photoresist. However, by varying the etching selectivity, one could control the curvature of the silicon microlens. The figure shows the microfabricated silicon microlens 5 x5 array. The diameter of the microlens located in the center is about 2.5 mm. The measured 3-D profile of the microlens surface has a

Discretely tunable micromachined injection-locked lasers

International Nuclear Information System (INIS)

Cai, H; Yu, M B; Lo, G Q; Kwong, D L; Zhang, X M; Liu, A Q; Liu, B

2010-01-01

This paper reports a micromachined injection-locked laser (ILL) to provide tunable discrete wavelengths. It utilizes a non-continuously tunable laser as the master to lock a Fabry–Pérot semiconductor laser chip. Both lasers are integrated into a deep-etched silicon chip with dimensions of 3 mm × 3 mm × 0.8 mm. Based on the experimental results, significant improvements in the optical power and spectral purity have been achieved in the fully locked state, and optical hysteresis and bistability have also been observed in response to the changes of the output wavelength and optical power of the master laser. As a whole system, the micromachined ILL is able to provide single mode, discrete wavelength tuning, high power and direct modulation with small size and single-chip solution, making it promising for advanced optical communications such as wavelength division multiplexing optical access networks.

SMM detection of diffuse Galactic 511 keV annihilation radiation

Science.gov (United States)

Share, G. H.; Kinzer, R. L.; Kurfess, J. D.; Messina, D. C.; Purcell, W. R.

1988-01-01

Observations of the 511 keV annihilation line from the vicinity of the Galactic center from October to February for 1980/1981, 1981/1982, 1982/1983, 1984/1985, and 1985/1986 are presented. The measurements were made with the gamma-ray spectrometer on the SMM. The design of the instrument and some of its properties used in the analysis are described, and the methods used for accumulating, fitting, and analyzing the data are outlined. It is shown how the Galactic 511 keV line was separated from the intense and variable background observed in orbit. The SMM observations are compared with previous measurements of annihilation radiation from the Galactic center region, and the astrophysical implications are discussed. It is argued that most of the measurements made to date suggest the presence of an extended Galactic source of annihilation radiation.

Trends in laser micromachining

Science.gov (United States)

Gaebler, Frank; van Nunen, Joris; Held, Andrew

2016-03-01

Laser Micromachining is well established in industry. Depending on the application lasers with pulse length from μseconds to femtoseconds and wavelengths from 1064nm and its harmonics up to 5μm or 10.6μm are used. Ultrafast laser machining using pulses with pico or femtosecond duration pulses is gaining traction, as it offers very precise processing of materials with low thermal impact. Large-scale industrial ultrafast laser applications show that the market can be divided into various sub segments. One set of applications demand low power around 10W, compact footprint and are extremely sensitive to the laser price whilst still demanding 10ps or shorter laser pulses. A second set of applications are very power hungry and only become economically feasible for large scale deployments at power levels in the 100+W class. There is also a growing demand for applications requiring fs-laser pulses. In our presentation we would like to describe these sub segments by using selected applications from the automotive and electronics industry e.g. drilling of gas/diesel injection nozzles, dicing of LED substrates. We close the presentation with an outlook to micromachining applications e.g. glass cutting and foil processing with unique new CO lasers emitting 5μm laser wavelength.

Polyimide as a versatile enabling material for microsystems fabrication: surface micromachining and electrodeposited nanowires integration

Science.gov (United States)

Walewyns, Thomas; Reckinger, Nicolas; Ryelandt, Sophie; Pardoen, Thomas; Raskin, Jean-Pierre; Francis, Laurent A.

2013-09-01

The interest of using polyimide as a sacrificial and anchoring layer is demonstrated for post-processing surface micromachining and for the incorporation of metallic nanowires into microsystems. In addition to properties like a high planarization factor, a good resistance to most non-oxidizing acids and bases, and CMOS compatibility, polyimide can also be used as a mold for nanostructures after ion track-etching. Moreover, specific polyimide grades, such as PI-2611 from HD Microsystems™, involve a thermal expansion coefficient similar to silicon and low internal stress. The process developed in this study permits higher gaps compared to the state-of-the-art, limits stiction problems with the substrate and is adapted to various top-layer materials. Most metals, semiconductors or ceramics will not be affected by the oxygen plasma required for polyimide etching. Released structures with vertical gaps from one to several tens of μm have been obtained, possibly using multiple layers of polyimide. Furthermore, patterned freestanding nanowires have been synthesized with diameters from 20 to 60 nm and up to 3 μm in length. These results have been applied to the fabrication of two specific devices: a generic nanomechanical testing lab-on-chip platform and a miniaturized ionization sensor.

A level set methodology for predicting the effect of mask wear on surface evolution of features in abrasive jet micro-machining

International Nuclear Information System (INIS)

Burzynski, T; Papini, M

2012-01-01

A previous implementation of narrow-band level set methodology developed by the authors was extended to allow for the modelling of mask erosive wear in abrasive jet micro-machining (AJM). The model permits the prediction of the surface evolution of both the mask and the target simultaneously, by representing them as a hybrid and continuous mask–target surface. The model also accounts for the change in abrasive mass flux incident to both the target surface and, for the first time, the eroding mask edge, that is brought about by the presence of the mask edge itself. The predictions of the channel surface and eroded mask profiles were compared with measurements on channels machined in both glass and poly-methyl-methacrylate (PMMA) targets at both normal and oblique incidence, using tempered steel and elastomeric masks. A much better agreement between the predicted and measured profiles was found when mask wear was taken into account. Mask wear generally resulted in wider and deeper glass target profiles and wider PMMA target profiles, respectively, when compared to cases where no mask wear was present. This work has important implications for the AJM of complex MEMS and microfluidic devices that require longer machining times. (paper)

A micromachined calorimetric gas sensor: an application of electrodeposited nanostructured palladium for the detection of combustible gases.

Science.gov (United States)

Bartlett, Philip N; Guerin, Samuel

2003-01-01

Palladium films with regular nanoarchitectures were electrochemically deposited from the hexagonal (H1) lyotropic liquid crystalline phase of the nonionic surfactant octaethyleneglycol monohexadecyl ether (C16EO8) onto micromachined silicon hotplate structures. The H1-e Pd films were shown to have high surface areas (approximately 28 m2 g(-1)) and to act as effective and stable catalysts for the detection of methane in air on heating to 500 degrees C. The response of the H1-e Pd-coated planar pellistors was found to be linearly proportional to the concentration of methane between 0 and 2.5% in air with a detection limit below 0.125%. Our results show that the electrochemical deposition of nanostructured metal films offers a promising approach to the fabrication of micromachined calorimetric gas sensors for combustible gases.

Sustainable Materials Management (SMM) Web Academy Webinar: The Changing Waste Stream

Science.gov (United States)

This is a webinar page for the Sustainable Management of Materials (SMM) Web Academy webinar titled Let’s WRAP (Wrap Recycling Action Program): Best Practices to Boost Plastic Film Recycling in Your Community

Mechanical characterization of biocompatible thin film materials by scanning along micro-machined cantilevers for micro-/nano-system

International Nuclear Information System (INIS)

He, J.H.; Luo, J.K.; Le, H.R.; Moore, D.F.

2006-01-01

Mechanical characterization is vital for the design of micro-/nano-electro-mechanical system (MEMS/NEMS). This paper describes a new characterization method to extract the mechanical properties of the thin film materials, which is simple, inexpensive and applicable to a wide range of materials including biocompatible ones described in this paper. The beams of the material under tests, are patterned by laser micro-machining and released by alkaline etch. A surface profilometer is used to scan along micro-machined cantilevers and produce a bending profile, from which the Young's modulus can be extracted. Biocompatible SiN x , SiC and nanocrystal diamond cantilevers have been fabricated and their Young's modulus has been evaluated as 154 ± 12, 360 ± 50 and 504 ± 50 GPa, respectively, which is consistent with those measured by nano-indentation. Residual stress gradient has also been extracted by surface profilometer, which is comparable with the results inferred from ZYGO interferometer measurements. This method can be extended to atomic force microscopy stylus or nanometer-stylus profilometer for Bio-NEMS mechanical characterization

Search for Doppler-shifted gamma-ray emission from SS 433 using the SMM spectrometer

International Nuclear Information System (INIS)

Geldzahler, B.J.; Share, G.H.; Kinzer, R.L.; Magura, J.; Chupp, E.L.

1989-01-01

Data accumulated from 1980 to 1983 with the Gamma Ray Spectrometer aboard NASA's Solar Maximum Mission (SMM) satellite were searched for evidence of red and blue Doppler-shifted 1.37 MeV Mg-24 nuclear lines from SS 433. The SMM data base covers 270 days when SS 433 was in the field of view and includes periods of radio flaring and quiescence. No evidence was found for Doppler-shifted line emission in any of the spectra. The range of 3-sigma upper limits for individual 9 day integration periods was 0.0008-0.0023 photons/sq cm per sec for the blue beam, encompassing the reported about 1.5 MeV line, and 0.0008-0.002 photons/sq cm per sec for the red beam, encompassing the reported about 1.2 MeV line; the average 3-sigma upper limit in each beam for shifted about 1.37 MeV lines is 0.0015 photons/sq cm per sec for single 9 day integrations. The 3-sigma upper limit on 1.37 MeV gamma-ray emission over 23 9-day integration intervals for the red beam and 28 intervals for the blue beam is 0.0002 photons/sq cm per sec. These new limits from SMM can be reconciled with the HEAO 3 results only if SS 433 emits gamma radiation at or above the SMM sensitivity limit on rare occasions due to variable physical conditions in the system. 19 refs

Search for Doppler-shifted gamma-ray emission from SS 433 using the SMM spectrometer

Science.gov (United States)

Geldzahler, B. J.; Share, G. H.; Kinzer, R. L.; Magura, J.; Chupp, E. L.

1989-01-01

Data accumulated from 1980 to 1983 with the Gamma Ray Spectrometer aboard NASA's Solar Maximum Mission (SMM) satellite were searched for evidence of red and blue Doppler-shifted 1.37 MeV Mg-24 nuclear lines from SS 433. The SMM data base covers 270 days when SS 433 was in the field of view and includes periods of radio flaring and quiescence. No evidence was found for Doppler-shifted line emission in any of the spectra. The range of 3-sigma upper limits for individual 9 day integration periods was 0.0008-0.0023 photons/sq cm per sec for the blue beam, encompassing the reported about 1.5 MeV line, and 0.0008-0.002 photons/sq cm per sec for the red beam, encompassing the reported about 1.2 MeV line; the average 3-sigma upper limit in each beam for shifted about 1.37 MeV lines is 0.0015 photons/sq cm per sec for single 9 day integrations. The 3-sigma upper limit on 1.37 MeV gamma-ray emission over 23 9-day integration intervals for the red beam and 28 intervals for the blue beam is 0.0002 photons/sq cm per sec. These new limits from SMM can be reconciled with the HEAO 3 results only if SS 433 emits gamma radiation at or above the SMM sensitivity limit on rare occasions due to variable physical conditions in the system.

High speed micromachining with high power UV laser

Science.gov (United States)

Patel, Rajesh S.; Bovatsek, James M.

2013-03-01

Increasing demand for creating fine features with high accuracy in manufacturing of electronic mobile devices has fueled growth for lasers in manufacturing. High power, high repetition rate ultraviolet (UV) lasers provide an opportunity to implement a cost effective high quality, high throughput micromachining process in a 24/7 manufacturing environment. The energy available per pulse and the pulse repetition frequency (PRF) of diode pumped solid state (DPSS) nanosecond UV lasers have increased steadily over the years. Efficient use of the available energy from a laser is important to generate accurate fine features at a high speed with high quality. To achieve maximum material removal and minimal thermal damage for any laser micromachining application, use of the optimal process parameters including energy density or fluence (J/cm2), pulse width, and repetition rate is important. In this study we present a new high power, high PRF QuasarR 355-40 laser from Spectra-Physics with TimeShiftTM technology for unique software adjustable pulse width, pulse splitting, and pulse shaping capabilities. The benefits of these features for micromachining include improved throughput and quality. Specific example and results of silicon scribing are described to demonstrate the processing benefits of the Quasar's available power, PRF, and TimeShift technology.

Speeds of coronal mass ejections: SMM observations from 1980 and 1984-1989

Science.gov (United States)

Hundhausen, A. J.; Burkepile, J. T.; St. Cyr, O. C.

1994-01-01

The speeds of 936 features in 673 coronal mass ejections have been determined from trajectories observed with the Solar Maximum Mission (SMM) coronagraph in 1980 and 1984 to 1989. The distribution of observed speeds has a range (from 5th to 95th percentile) of 35 to 911 km/s; the average and median speeds are 349 and 285 km/s. The speed distributions of some selected classes of mass ejections are significantly different. For example, the speeds of 331 'outer loops' range from 80 to 1042 km/s; the average and median speeds for this class of ejections are 445 and 372 km/s. The speed distributions from each year of SMM observations show significant changes, with the annual average speeds varying from 157 (1984) to 458 km/s (1985). These variations are not simply related to the solar activity cycle; the annual averages from years near the sunspot maxima and minimum are not significantly different. The widths, latitudes, and speeds of mass ejections determined from the SMM observations are only weakly correlated. In particular, mass ejection speeds vary only slightly with the heliographic latitudes of the ejection. High-latitude ejections, which occur well poleward of the active latitudes, have speeds similar to active latitude ejections.

Analysis of the flight dynamics of the Solar Maximum Mission (SMM) off-sun scientific pointing

Science.gov (United States)

Pitone, D. S.; Klein, J. R.; Twambly, B. J.

1990-01-01

Algorithms are presented which were created and implemented by the Goddard Space Flight Center's (GSFC's) Solar Maximum Mission (SMM) attitude operations team to support large-angle spacecraft pointing at scientific objectives. The mission objective of the post-repair SMM satellite was to study solar phenomena. However, because the scientific instruments, such as the Coronagraph/Polarimeter (CP) and the Hard X-ray Burst Spectrometer (HXRBS), were able to view objects other than the Sun, attitude operations support for attitude pointing at large angles from the nominal solar-pointing attitudes was required. Subsequently, attitude support for SMM was provided for scientific objectives such as Comet Halley, Supernova 1987A, Cygnus X-1, and the Crab Nebula. In addition, the analysis was extended to include the reverse problem, computing the right ascension and declination of a body given the off-Sun angles. This analysis led to the computation of the orbits of seven new solar comets seen in the field-of-view (FOV) of the CP. The activities necessary to meet these large-angle attitude-pointing sequences, such as slew sequence planning, viewing-period prediction, and tracking-bias computation are described. Analysis is presented for the computation of maneuvers and pointing parameters relative to the SMM-unique, Sun-centered reference frame. Finally, science data and independent attitude solutions are used to evaluate the larg-angle pointing performance.

Controllable magnetic thermal rectification in a SMM dimmer with the Dzyaloshinskii-Moriya interaction

Science.gov (United States)

Xu, Ai-Hua; Liu, Juan; Luo, Bo

2016-10-01

Using the quantum master equation, we studied the thermally driven magnonic spin current in a single-molecule magnet (SMM) dimer with the Dzyaloshinskii-Moriya interaction (DMI). Due to the asymmetric DMI, one can observe the thermal rectifying effect in the case of the spatial symmetry coupling with the thermal reservoirs. The properties of the thermal rectification can be controlled by tuning the angle and intensity of the magnetic field. Specially, when the DM vector and magnetic field point at the specific angles, the thermal rectifying effect disappears. And this phenomenon does not depend on the intensities of DMI and magnetic field, the temperature bias and the magnetic anisotropies of the SMM.

Temperature dependence of attitude sensor coalignments on the Solar Maximum Mission (SMM)

Science.gov (United States)

Pitone, D. S.; Eudell, A. H.; Patt, F. S.

1990-01-01

The temperature correlation of the relative coalignment between the fine-pointing sun sensor and fixed-head star trackers measured on the Solar Maximum Mission (SMM) is analyzed. An overview of the SMM, including mission history and configuration, is given. Possible causes of the misalignment variation are discussed, with focus placed on spacecraft bending due to solar-radiation pressure, electronic or mechanical changes in the sensors, uncertainty in the attitude solutions, and mounting-plate expansion and contraction due to thermal effects. Yaw misalignment variation from the temperature profile is assessed, and suggestions for spacecraft operations are presented, involving methods to incorporate flight measurements of the temperature-versus-alignment function and its variance in operational procedures and the spacecraft structure temperatures in the attitude telemetry record.

Post-flare coronal arches observed with the SMM/XRP flat crystal spectrometer

Science.gov (United States)

Hick, Paul; Svestka, Zdenek; Smith, Kermit L.; Strong, Keith T.

1987-01-01

Postflare coronal arch observations made with the SMM Flat Crystal Spectrometer on January 20-23, 1985 are discussed. Results suggest that the arch revival following the dynamic flare of 23:50 UT on January 1 was of the type noted on November 6-8 and June 4, 1980 by the SMM Hard X-ray Imaging Spectrometer (HXIS). Activity different from that of the HXIS observations was found starting at about 23 UT on January 22, with no trigger of the revival being identified, and with the activity being restricted to the coronal regions (without any related disturbance in the chromosphere). The development of the arch enhancement in the corona was shown to be slower than is expected for a flare-associated revival.

Micromachined Thin-Film Sensors for SOI-CMOS Co-Integration

Science.gov (United States)

Laconte, Jean; Flandre, D.; Raskin, Jean-Pierre

Co-integration of sensors with their associated electronics on a single silicon chip may provide many significant benefits regarding performance, reliability, miniaturization and process simplicity without significantly increasing the total cost. Micromachined Thin-Film Sensors for SOI-CMOS Co-integration covers the challenges and interests and demonstrates the successful co-integration of gas flow sensors on dielectric membrane, with their associated electronics, in CMOS-SOI technology. We firstly investigate the extraction of residual stress in thin layers and in their stacking and the release, in post-processing, of a 1 μm-thick robust and flat dielectric multilayered membrane using Tetramethyl Ammonium Hydroxide (TMAH) silicon micromachining solution.

Model Design of Piezoelectric Micromachined Modal Gyroscope

Directory of Open Access Journals (Sweden)

Xiaojun Hu

2011-01-01

Full Text Available This paper reports a novel kind of solid-state microgyroscope, which is called piezoelectric micromachined modal gyroscope (PMMG. PMMG has large stiffness and robust resistance to shake and strike because there is no evident mass-spring component in its structure. This work focused on quantitative optimization of the gyroscope, which is still blank for such gyroscope. The modal analysis by the finite element method (FEM was firstly conducted. A set of quantitative indicators were developed to optimize the operation mode. By FEM, the harmonic analysis was conducted to find the way to efficiently actuate the operational mode needed. The optimal configuration of driving electrodes was obtained. At last, the Coriolis analysis was conducted to show the relation between angular velocity and differential output voltage by the Coriolis force under working condition. The results obtained in this paper provide theoretical basis for realizing this novel kind of micromachined gyroscope.

Observations of Galactic gamma-radiation with the SMM spectrometer

Science.gov (United States)

Share, G. H.; Kinzer, R. L.; Messina, D. C.; Purcell, W. R.; Chupp, E. L.

1986-01-01

Preliminary results from the SMM gamma-ray spectrometer are reported which indicate the detection of a constant source of 0.511-MeV annihilation radiation from the Galaxy. Year-to-year variability appears to be less than 30 percent. The radiation probably comes from a diffuse source and is not associated with the reported compact object at the Galactic center.

Sandwich-type tetrakis(phthalocyaninato) dysprosium-cadmium quadruple-decker SMM.

Science.gov (United States)

Wang, Hailong; Qian, Kang; Wang, Kang; Bian, Yongzhong; Jiang, Jianzhuang; Gao, Song

2011-09-14

Homoleptic tetrakis[2,3,9,10,16,17,23,24-octa(butyloxy)phthalocyaninato] dysprosium-cadmium quadruple-decker complex 1 was isolated in relatively good yield of 43% from a simple one-pot reaction. This compound represents the first sandwich-type tetrakis(phthalocyaninato) rare earth-cadmium quadruple-decker SMM that has been structurally characterized. This journal is © The Royal Society of Chemistry 2011

A symmetric, triply interlaced 3-D anionic MOF that exhibits both magnetic order and SMM behaviour.

Science.gov (United States)

Campo, J; Falvello, L R; Forcén-Vázquez, E; Sáenz de Pipaón, C; Palacio, F; Tomás, M

2016-11-14

A newly prepared 3-D polymer of cobalt citrate cubanes bridged by high-spin Co(ii) centres displays both single-molecule magnet (SMM) behaviour and magnetic ordering. Triple interpenetration of the 3-D diamondoid polymers yields a crystalline solid with channels that host cations and free water molecules, with the SMM behaviour of the Co 4 O 4 cores preserved. The octahedrally coordinated Co(ii) bridges are implicated in the onset of magnetic order at an experimentally accessible temperature.

Fabrication of a Micromachined Capacitive Switch Using the CMOS-MEMS Technology

Directory of Open Access Journals (Sweden)

Cheng-Yang Lin

2015-11-01

Full Text Available The study investigates the design and fabrication of a micromachined radio frequency (RF capacitive switch using the complementary metal oxide semiconductor-microelectromechanical system (CMOS-MEMS technology. The structure of the micromachined switch is composed of a membrane, eight springs, four inductors, and coplanar waveguide (CPW lines. In order to reduce the actuation voltage of the switch, the springs are designed as low stiffness. The finite element method (FEM software CoventorWare is used to simulate the actuation voltage and displacement of the switch. The micromachined switch needs a post-CMOS process to release the springs and membrane. A wet etching is employed to etch the sacrificial silicon dioxide layer, and to release the membrane and springs of the switch. Experiments show that the pull-in voltage of the switch is 12 V. The switch has an insertion loss of 0.8 dB at 36 GHz and an isolation of 19 dB at 36 GHz.

VERY LARGE ARRAY MAPPING OF THE CO(1-0) LINE IN SMM J14011+0252

Energy Technology Data Exchange (ETDEWEB)

Sharon, Chelsea E.; Baker, Andrew J. [Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854-8019 (United States); Harris, Andrew I. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Thomson, Alasdair P., E-mail: csharon@physics.rutgers.edu, E-mail: ajbaker@physics.rutgers.edu, E-mail: harris@astro.umd.edu, E-mail: at@roe.ac.uk [Institute for Astronomy, University of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom)

2013-03-01

We present high-resolution CO(1-0) observations of the lensed submillimeter galaxy (SMG) SMM J14011+0252 at z = 2.6. Comparison to the previously detected CO(3-2) line gives an intensity ratio of r {sub 3,1} = 0.97 {+-} 0.16 in temperature units, larger than is typical for SMGs but within the range seen in the low-z ultraluminous infrared galaxy population. Combining our new data with previous mid-J CO observations, we perform a single-phase large velocity gradient (LVG) analysis to constrain the physical conditions of the molecular gas. Acceptable models have significant degeneracies between parameters, even when we rule out all models that produce optically thin emission, but we find that the bulk of the molecular gas has T {sub kin} = 20-60 K, n{sub H{sub 2}}{approx}10{sup 4}-10{sup 5} cm{sup -3}, and N {sub CO}/{Delta}v = 10{sup 17.00{+-}0.25} cm{sup -2} km{sup -1} s. For our best-fit models to self-consistently recover a typical CO-to-H{sub 2} abundance and a plausible degree of virialization, the local velocity gradient in the molecular gas must be substantially larger than its galaxy-wide average. This conclusion is consistent with a scenario in which SMM J14011+0252 has a fairly face-on orientation and a molecular interstellar medium composed of many unresolved clouds. Using previous H{alpha} observations, we find that SMM J14011+0252 has a spatially resolved star formation rate versus molecular gas surface density relation inconsistent with those of 'normal' local star-forming galaxies, even if we adopt a local 'disk-like' CO-to-H{sub 2} conversion factor as motivated by our LVG analysis. This discrepancy supports the inference of a star formation relation for high-z starbursts distinct from the local relation that is not solely due to differing choices of gas mass conversion factor.

Development of SMM wave laser scattering apparatus for the measurements of waves and turbulences in the tokamak plasma

International Nuclear Information System (INIS)

Saito, T.; Hamada, Y.; Yamashita, T.; Ikeda, M.; Nakamura, M.

1980-01-01

The SMM wave laser scattering apparatus has been developed for the measurement of the waves and turbulences in the plasma. This apparatus will help greatly to clarify the physics of RF heating of the tokamak plasma. The present status of main parts of the apparatus, the SMM wave laser and the Schottky barrier diode mixer for the heterodyne receiver, are described. (author)

Resonant gravimetric immunosensing based on capacitive micromachined ultrasound transducers

KAUST Repository

Viržonis, Darius

2014-04-08

High-frequency (40 MHz) and low-frequency (7 MHz) capacitive micromachined ultrasound transducers (CMUT) were fabricated and tested for use in gravimetric detection of biomolecules. The low-frequency CMUT sensors have a gold-coated surface, while the high-frequency sensors have a silicon nitride surface. Both surfaces were functionalized with bovine leukemia virus antigen gp51 acting as the antigen. On addition of an a specific antibody labeled with horseradish peroxidase (HRP), the antigen/antibody complex is formed on the surface and quantified by HRP-catalyzed oxidation of tetramethylbenzidine. It has been found that a considerably smaller quantity of immuno complex is formed on the high frequency sensor surface. In parallel, the loading of the surface of the CMUT was determined via resonance frequency and electromechanical resistance readings. Following the formation of the immuno complexes, the resonance frequencies of the low-frequency and high-frequency sensors decrease by up to 420 and 440 kHz, respectively. Finite element analysis reveals that the loading of the (gold-coated) low frequency sensors is several times larger than that on high frequency sensors. The formation of the protein film with pronounced elasticity and stress on the gold surface case is discussed. We also discuss the adoption of this method for the detection of DNA using a hybridization assay following polymerase chain reaction.

Micromachined Piezoelectric Actuators for Cryogenic Adaptive Optics, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — TRS Technologies proposes micromachined single crystal piezoelectric actuator arrays to enable ultra-large stroke, high precision shape control for large aperture,...

High lane density slab-gel electrophoresis using micromachined instrumentation.

Science.gov (United States)

Papautsky, I; Mohanty, S; Weiss, R; Frazier, A B

2001-10-01

In this paper, micromachined pipette arrays (MPAs) and microcombs were studied as a means of enabling high lane density gel electrophoresis. The MPA provide a miniaturized format to interface sub-microliter volumes of samples between macroscale sample preparation formats and microscale biochemical analysis systems. The microcombs provide a means of creating sample loading wells in the gel material on the same center-to-center spacing as the MPAs. Together, the two micromachined instruments provide an alternative to current combs and pipetting technologies used for creating sample loading wells and sample delivery in gel electrophoresis systems. Using three designs for the microcomb-MPA pair, center-to-center spacings of 1.0 mm, 500 microm, and 250 microm are studied. The results demonstrate an approximate 10-fold increase in lane density and a 10-fold reduction in sample size from 5 microL to 500 pL. As a result, the number of theoretical plates has increased 2.5-fold, while system resolution has increased 1.5-fold over the conventional agarose gel systems. An examination of changes in resolution across the width of individual separation lanes in both systems revealed dependence in the case of the conventional gels and no dependence for the gels loaded with the micromachined instrumentation.

New technique for fabrication of high frequency piezoelectric Micromachined Ultrasound Transducers

DEFF Research Database (Denmark)

Pedersen, T; Thomsen, Erik Vilain; Zawada, T

2008-01-01

A novel technique for fabrication of linear arrays of high frequency piezoelectric Micromachined Ultrasound Transducers (pMUT) on silicon substrates is presented. Piezoelectric elements are formed by deposition of PZT ((PbZrxTi1-x)O3) into etched features of the silicon substrate such that the de......A novel technique for fabrication of linear arrays of high frequency piezoelectric Micromachined Ultrasound Transducers (pMUT) on silicon substrates is presented. Piezoelectric elements are formed by deposition of PZT ((PbZrxTi1-x)O3) into etched features of the silicon substrate...

Fabrication of a novel quartz micromachined gyroscope

Science.gov (United States)

Xie, Liqiang; Xing, Jianchun; Wang, Haoxu; Wu, Xuezhong

2015-04-01

A novel quartz micromachined gyroscope is proposed in this paper. The novel gyroscope is realized by quartz anisotropic wet etching and 3-dimensional electrodes deposition. In the quartz wet etching process, the quality of Cr/Au mask films affecting the process are studied by experiment. An excellent mask film with 100 Å Cr and 2000 Å Au is achieved by optimization of experimental parameters. Crystal facets after etching seriously affect the following sidewall electrodes deposition process and the structure's mechanical behaviours. Removal of crystal facets is successfully implemented by increasing etching time based on etching rate ratios between facets and crystal planes. In the electrodes deposition process, an aperture mask evaporation method is employed to prepare electrodes on 3-dimensional surfaces of the gyroscope structure. The alignments among the aperture masks are realized by the ABM™ Mask Aligner System. Based on the processes described above, a z-axis quartz gyroscope is fabricated successfully.

Integration of Capacitive Micromachined Ultrasound Transducers to Microfluidic Devices

KAUST Repository

Viržonis, Darius; Kodzius, Rimantas; Vanagas, Galius

2013-01-01

The design and manufacturing flexibility of capacitive micromachined ultrasound transducers (CMUT) makes them attractive option for integration with microfluidic devices both for sensing and fluid manipulation. CMUT concept is introduced here

Silicon Micromachines for Science and Technology

International Nuclear Information System (INIS)

Bishop, David J.

2002-01-01

The era of silicon micromechanics is upon us. In areas as diverse as telecommunications, automotive, aerospace, chemistry, entertainment and basic science, the ability to build microscopic machines from silicon is having a revolutionary impact. In my talk, I will discuss what micromachines are, how they are built and show examples of how they will have a revolutionary impact in many areas of science as well as technology.

Sizes and locations of coronal mass ejections - SMM observations from 1980 and 1984-1989

Science.gov (United States)

Hundhausen, A. J.

1993-01-01

A statistical description of the sizes and locations of 1209 mass ejections observed with the SMM coronagraph/polarimeter in 1980 and 1984-1989 is presented. The average width of the coronal mass ejections detected with this instrument was close to 40 deg in angle for the entire period of SMM observations. No evidence was found for a significant change in mass ejection widths as reported by Howard et al. (1986). There is clear evidence for changes in the latitude distribution of mass ejections over this epoch. Mass ejections occurred over a much wider range of latitudes at the times of high solar activity (1980 and 1989) than at times of low activity (1985-1986).

Micro-machined calorimetric biosensors

Science.gov (United States)

Doktycz, Mitchel J.; Britton, Jr., Charles L.; Smith, Stephen F.; Oden, Patrick I.; Bryan, William L.; Moore, James A.; Thundat, Thomas G.; Warmack, Robert J.

2002-01-01

A method and apparatus are provided for detecting and monitoring micro-volumetric enthalpic changes caused by molecular reactions. Micro-machining techniques are used to create very small thermally isolated masses incorporating temperature-sensitive circuitry. The thermally isolated masses are provided with a molecular layer or coating, and the temperature-sensitive circuitry provides an indication when the molecules of the coating are involved in an enthalpic reaction. The thermally isolated masses may be provided singly or in arrays and, in the latter case, the molecular coatings may differ to provide qualitative and/or quantitative assays of a substance.

Integration of Capacitive Micromachined Ultrasound Transducers to Microfluidic Devices

KAUST Repository

Viržonis, Darius

2013-10-22

The design and manufacturing flexibility of capacitive micromachined ultrasound transducers (CMUT) makes them attractive option for integration with microfluidic devices both for sensing and fluid manipulation. CMUT concept is introduced here by presentin

Quasimetallic silicon micromachined photonic crystals

International Nuclear Information System (INIS)

Temelkuran, B.; Bayindir, Mehmet; Ozbay, E.; Kavanaugh, J. P.; Sigalas, M. M.; Tuttle, G.

2001-01-01

We report on fabrication of a layer-by-layer photonic crystal using highly doped silicon wafers processed by semiconductor micromachining techniques. The crystals, built using (100) silicon wafers, resulted in an upper stop band edge at 100 GHz. The transmission and defect characteristics of these structures were found to be analogous to metallic photonic crystals. We also investigated the effect of doping concentration on the defect characteristics. The experimental results agree well with predictions of the transfer matrix method simulations

Micromachined Polycrystalline Si Thermopiles in a T-shirt

Directory of Open Access Journals (Sweden)

Vladimir Leonov

2011-04-01

Full Text Available The technology for in-plane poly-Si thermopiles has been developed. The bulk-micromachined thermopiles are located between two Si bars and connected thermally with those bars through thin-film thermal shunts. The patterned strips of thermocouple material together with thermal shunts form bridges between Si bars. Two versions of a thermoelectric generator (TEG with micromachined thermopiles have been assembled and tested on a person’s wrist, and when integrated in a T-shirt. The TEG still produces less than 1 μW in the office, but at ambient temperatures below 11-13 °C it produces more than 1 μW at a voltage of more than 2 V on the matched load. The new way of integration of wearable TEG in clothing is shown. The TEG is located under the textile, and the fabric is used as a flexible radiator.

Predicting the Deflections of Micromachined Electrostatic Actuators Using Artificial Neural Network (ANN

Directory of Open Access Journals (Sweden)

Hing Wah LEE

2009-03-01

Full Text Available In this study, a general purpose Artificial Neural Network (ANN model based on the feed-forward back-propagation (FFBP algorithm has been used to predict the deflections of a micromachined structures actuated electrostatically under different loadings and geometrical parameters. A limited range of simulation results obtained via CoventorWare™ numerical software will be used initially to train the neural network via back-propagation algorithm. The micromachined structures considered in the analyses are diaphragm, fixed-fixed beams and cantilevers. ANN simulation results are compared with results obtained via CoventorWare™ simulations and existing analytical work for validation purpose. The proposed ANN model accurately predicts the deflections of the micromachined structures with great reduction of simulation efforts, establishing the method superiority. This method can be extended for applications in other sensors particularly for modeling sensors applying electrostatic actuation which are difficult in nature due to the inherent non-linearity of the electro-mechanical coupling response.

Dual-beam focused ion beam/electron microscopy processing and metrology of redeposition during ion-surface 3D interactions, from micromachining to self-organized picostructures.

Science.gov (United States)

Moberlychan, Warren J

2009-06-03

Focused ion beam (FIB) tools have become a mainstay for processing and metrology of small structures. In order to expand the understanding of an ion impinging a surface (Sigmund sputtering theory) to our processing of small structures, the significance of 3D boundary conditions must be realized. We consider ion erosion for patterning/lithography, and optimize yields using the angle of incidence and chemical enhancement, but we find that the critical 3D parameters are aspect ratio and redeposition. We consider focused ion beam sputtering for micromachining small holes through membranes, but we find that the critical 3D considerations are implantation and redeposition. We consider ion beam self-assembly of nanostructures, but we find that control of the redeposition by ion and/or electron beams enables the growth of nanostructures and picostructures.

Novel in situ mechanical testers to enable integrated metal surface micro-machines.

Energy Technology Data Exchange (ETDEWEB)

Follstaedt, David Martin; de Boer, Maarten Pieter; Kotula, Paul Gabriel; Hearne, Sean Joseph; Foiles, Stephen Martin; Buchheit, Thomas Edward; Dyck, Christopher William

2005-10-01

The ability to integrate metal and semiconductor micro-systems to perform highly complex functions, such as RF-MEMS, will depend on developing freestanding metal structures that offer improved conductivity, reflectivity, and mechanical properties. Three issues have prevented the proliferation of these systems: (1) warpage of active components due to through-thickness stress gradients, (2) limited component lifetimes due to fatigue, and (3) low yield strength. To address these issues, we focus on developing and implementing techniques to enable the direct study of the stress and microstructural evolution during electrodeposition and mechanical loading. The study of stress during electrodeposition of metal thin films is being accomplished by integrating a multi-beam optical stress sensor into an electrodeposition chamber. By coupling the in-situ stress information with ex-situ microstructural analysis, a scientific understanding of the sources of stress during electrodeposition will be obtained. These results are providing a foundation upon which to develop a stress-gradient-free thin film directly applicable to the production of freestanding metal structures. The issues of fatigue and yield strength are being addressed by developing novel surface micromachined tensile and bend testers, by interferometry, and by TEM analysis. The MEMS tensile tester has a ''Bosch'' etched hole to allow for direct viewing of the microstructure in a TEM before, during, and after loading. This approach allows for the quantitative measurements of stress-strain relations while imaging dislocation motion, and determination of fracture nucleation in samples with well-known fatigue/strain histories. This technique facilitates the determination of the limits for classical deformation mechanisms and helps to formulate a new understanding of the mechanical response as the grain sizes are refined to a nanometer scale. Together, these studies will result in a science

The Influence of Coating Structure on Micromachine Stiction

Energy Technology Data Exchange (ETDEWEB)

Kushmerick, J.G.; Hankins, M.G.; De Boer, M.P.; Clews, P.J.; Carpick, R.W.; Bunker, B.C.

2000-10-03

We have clearly shown that the film morphology dictates the anti-stiction properties of FDTS coatings. Release stiction is not observed when ideal monolayer films are present but can be extensive when thicker aggregate structures are present. This finding is significant because it indicates that agglomerate formation during processing is a major source of irreproducible behavior when FDTS coatings are used to release micromachined parts. The results could also help explain why coatings that are aged at high. humidity start to stick to each other. (AFM results show that humid environments promote the formation of aggregates from monolayer films.) The reason why aggregate structures promote stiction is currently unknown. However, it appears that aggregates interfere with the ability of FDTS to form dense, well-ordered coatings under microstructures, leading to surfaces that are sufficiently hydrophilic to allow for release stiction via an attractive Laplace force during drying.

Bone induction by surface-double-modified true bone ceramics in vitro and in vivo

International Nuclear Information System (INIS)

Li, Jingfeng; Chen, Liaobin; Deng, Yu; Zheng, Qixin; Guo, Xiaodong; Zou, Zhenwei; Liu, Yudong; Lan, Shenghui

2013-01-01

True bone ceramic (TBC), obtained by twice sintering fresh bovine cancellous bone at high temperatures, is an osteoconductive and bioactive bone substitute material that exhibits excellent biocompatibility with hard tissue. The authors have previously synthesized a novel BMP-2-related peptide, P24, and found that it could enhance the osteoblastic differentiation of cells. The objective of the present study was to construct a double-modified TBC via mineralization into simulated body fluid and P24 incorporation for enhanced bone formation. In vitro experiments revealed that surface mineralization-modified (SMM) TBC scaffolds demonstrated efficiency for sustained release of P24. The P24/SMM-TBC composite exhibited increased osteogenic activity by cell adhesion rate determination, MTT assay, alkaline phosphatase staining, and calcium nodule staining with alizarin red compared with SMM-TBC and TBC. In vivo studies showed that the P24/SMM-TBC composite scaffold promoted significant bone defect repair, in marked contrast to stand-alone SMM-TBC and TBC, based on the results of radiographic evaluation and histological examination. These findings indicate that SMM-TBC is a good scaffold for the controlled release of P24 and that the P24/SMM-TBC composite could improve the adhesion, proliferation and differentiation of cells and repair bone defects. The double-modified P24/SMM-TBC composite biomaterial shows potential for clinical application in bone tissue engineering. (paper)

SMM mesospheric ozone measurements

Science.gov (United States)

Aikin, A. C.

1990-01-01

The main objective was to understand the secular and seasonal behavior of ozone in the lower mesosphere, 50 to 70 km. This altitude region is important in understanding the factors which determine ozone behavior. A secondary objective is the study of stratospheric ozone in the polar regions. Use is made of results from the SBUV satellite borne instrument. In the Arctic the interaction between chlorine compounds and low molecular weight hydrocarbons is studied. More than 30,000 profiles were obtained using the UVSP instrument on the SMM spacecraft. Several orbits of ozone data per day were obtained allowing study of the current rise in solar activity from the minimum until the present. Analysis of Nimbus 7 SBUV data in Antarctic spring indicates that ozone is depleted within the polar vortex relative to ozone outside the vortex. This depletion confirms the picture of ozone loss at altitudes where polar stratospheric clouds exist. In addition, there is ozone loss above the cloud level indicating that there is another mechanism in addition to ozone loss initiated by heterogeneous chlorine reactions on cloud particles.

Neuronal apoptotic signaling pathways probed and intervened by synthetically and modularly modified (SMM) chemokines.

Science.gov (United States)

Choi, Won-Tak; Kaul, Marcus; Kumar, Santosh; Wang, Jun; Kumar, I M Krishna; Dong, Chang-Zhi; An, Jing; Lipton, Stuart A; Huang, Ziwei

2007-03-09

As the main coreceptors for human immunodeficiency virus type 1 (HIV-1) entry, CXCR4 and CCR5 play important roles in HIV-associated dementia (HAD). HIV-1 glycoprotein gp120 contributes to HAD by causing neuronal damage and death, either directly by triggering apoptotic pathways or indirectly by stimulating glial cells to release neurotoxins. Here, to understand the mechanism of CXCR4 or CCR5 signaling in neuronal apoptosis associated with HAD, we have applied synthetically and modularly modified (SMM)-chemokine analogs derived from natural stromal cell-derived factor-1alpha or viral macrophage inflammatory protein-II as chemical probes of the mechanism(s) whereby these SMM-chemokines prevent or promote neuronal apoptosis. We show that inherently neurotoxic natural ligands of CXCR4, such as stromal cell-derived factor-1alpha or viral macrophage inflammatory protein-II, can be modified to protect neurons from apoptosis induced by CXCR4-preferring gp120(IIIB), and that the inhibition of CCR5 by antagonist SMM-chemokines, unlike neuroprotective CCR5 natural ligands, leads to neurotoxicity by activating a p38 mitogen-activated protein kinase (MAPK)-dependent pathway. Furthermore, we discover distinct signaling pathways activated by different chemokine ligands that are either natural agonists or synthetic antagonists, thus demonstrating a chemical biology strategy of using chemically engineered inhibitors of chemokine receptors to study the signaling mechanism of neuronal apoptosis and survival.

Apparatus for precision micromachining with lasers

Science.gov (United States)

Chang, J.J.; Dragon, E.P.; Warner, B.E.

1998-04-28

A new material processing apparatus using a short-pulsed, high-repetition-rate visible laser for precision micromachining utilizes a near diffraction limited laser, a high-speed precision two-axis tilt-mirror for steering the laser beam, an optical system for either focusing or imaging the laser beam on the part, and a part holder that may consist of a cover plate and a back plate. The system is generally useful for precision drilling, cutting, milling and polishing of metals and ceramics, and has broad application in manufacturing precision components. Precision machining has been demonstrated through percussion drilling and trepanning using this system. With a 30 W copper vapor laser running at multi-kHz pulse repetition frequency, straight parallel holes with size varying from 500 microns to less than 25 microns and with aspect ratios up to 1:40 have been consistently drilled with good surface finish on a variety of metals. Micromilling and microdrilling on ceramics using a 250 W copper vapor laser have also been demonstrated with good results. Materialographic sections of machined parts show little (submicron scale) recast layer and heat affected zone. 1 fig.

Sustainable Materials Management (SMM) Web Academy Webinar: Reducing Wasted Food: How Packaging Can Help

Science.gov (United States)

This is a webinar page for the Sustainable Management of Materials (SMM) Web Academy webinar titled Let’s WRAP (Wrap Recycling Action Program): Best Practices to Boost Plastic Film Recycling in Your Community

Modeling and Experimental Study on Characterization of Micromachined Thermal Gas Inertial Sensors

Directory of Open Access Journals (Sweden)

Yan Su

2010-09-01

Full Text Available Micromachined thermal gas inertial sensors based on heat convection are novel devices that compared with conventional micromachined inertial sensors offer the advantages of simple structures, easy fabrication, high shock resistance and good reliability by virtue of using a gaseous medium instead of a mechanical proof mass as key moving and sensing elements. This paper presents an analytical modeling for a micromachined thermal gas gyroscope integrated with signal conditioning. A simplified spring-damping model is utilized to characterize the behavior of the sensor. The model relies on the use of the fluid mechanics and heat transfer fundamentals and is validated using experimental data obtained from a test-device and simulation. Furthermore, the nonideal issues of the sensor are addressed from both the theoretical and experimental points of view. The nonlinear behavior demonstrated in experimental measurements is analyzed based on the model. It is concluded that the sources of nonlinearity are mainly attributable to the variable stiffness of the sensor system and the structural asymmetry due to nonideal fabrication.

A flexible ultrasound transducer array with micro-machined bulk PZT.

Science.gov (United States)

Wang, Zhe; Xue, Qing-Tang; Chen, Yuan-Quan; Shu, Yi; Tian, He; Yang, Yi; Xie, Dan; Luo, Jian-Wen; Ren, Tian-Ling

2015-01-23

This paper proposes a novel flexible piezoelectric micro-machined ultrasound transducer, which is based on PZT and a polyimide substrate. The transducer is made on the polyimide substrate and packaged with medical polydimethylsiloxane. Instead of etching the PZT ceramic, this paper proposes a method of putting diced PZT blocks into holes on the polyimide which are pre-etched. The device works in d31 mode and the electromechanical coupling factor is 22.25%. Its flexibility, good conformal contacting with skin surfaces and proper resonant frequency make the device suitable for heart imaging. The flexible packaging ultrasound transducer also has a good waterproof performance after hundreds of ultrasonic electric tests in water. It is a promising ultrasound transducer and will be an effective supplementary ultrasound imaging method in the practical applications.

A Flexible Ultrasound Transducer Array with Micro-Machined Bulk PZT

Directory of Open Access Journals (Sweden)

Zhe Wang

2015-01-01

Full Text Available This paper proposes a novel flexible piezoelectric micro-machined ultrasound transducer, which is based on PZT and a polyimide substrate. The transducer is made on the polyimide substrate and packaged with medical polydimethylsiloxane. Instead of etching the PZT ceramic, this paper proposes a method of putting diced PZT blocks into holes on the polyimide which are pre-etched. The device works in d31 mode and the electromechanical coupling factor is 22.25%. Its flexibility, good conformal contacting with skin surfaces and proper resonant frequency make the device suitable for heart imaging. The flexible packaging ultrasound transducer also has a good waterproof performance after hundreds of ultrasonic electric tests in water. It is a promising ultrasound transducer and will be an effective supplementary ultrasound imaging method in the practical applications.

Sub-band-gap laser micromachining of lithium niobate

DEFF Research Database (Denmark)

Christensen, F. K.; Müllenborn, Matthias

1995-01-01

method is reported which enables us to do laser processing of lithium niobate using sub-band-gap photons. Using high scan speeds, moderate power densities, and sub-band-gap photon energies results in volume removal rates in excess of 106µm3/s. This enables fast micromachining of small piezoelectric...

The Laser MicroJet (LMJ): a multi-solution technology for high quality micro-machining

Science.gov (United States)

Mai, Tuan Anh; Richerzhagen, Bernold; Snowdon, Paul C.; Wood, David; Maropoulos, Paul G.

2007-02-01

The field of laser micromachining is highly diverse. There are many different types of lasers available in the market. Due to their differences in irradiating wavelength, output power and pulse characteristic they can be selected for different applications depending on material and feature size [1]. The main issues by using these lasers are heat damages, contamination and low ablation rates. This report examines on the application of the Laser MicroJet(R) (LMJ), a unique combination of a laser beam with a hair-thin water jet as a universal tool for micro-machining of MEMS substrates, as well as ferrous and non-ferrous materials. The materials include gallium arsenide (GaAs) & silicon wafers, steel, tantalum and alumina ceramic. A Nd:YAG laser operating at 1064 nm (infra red) and frequency doubled 532 nm (green) were employed for the micro-machining of these materials.

PASCHEN-α EMISSION IN THE GRAVITATIONALLY LENSED GALAXY SMM J163554.2+661225

International Nuclear Information System (INIS)

Papovich, Casey; Finkelstein, Steven L.; Rudnick, Gregory; Rigby, Jane R.; Willmer, Christopher N. A.; Egami, Eiichi; Rieke, Marcia; Smith, J.-D. T.

2009-01-01

We report the detection of the Paα emission line in the z = 2.515 galaxy SMM J163554.2+661225 using Spitzer spectroscopy. SMM J163554.2+661225 is a submillimeter-selected infrared-luminous galaxy maintaining a high star formation rate (SFR), with no evidence of an active galactic nucleus from optical or infrared spectroscopy, nor X-ray emission. This galaxy is lensed gravitationally by the cluster Abell 2218, making it accessible to Spitzer spectroscopy. We measure a line luminosity, L(Paα) = (2.05 ± 0.33) x 10 42 erg s -1 , corrected for gravitational lensing. Comparing the Hα and Paα luminosities, we derive a nebular extinction, A(V) = 3.6 ± 0.4 mag. The dust-corrected luminosity, L(Paα) = (2.57 ± 0.43) x 10 42 erg s -1 , corresponds to an ionization rate, Q 0 = (1.6 ± 0.3) x 10 55 γ s -1 . The instantaneous SFR is ψ = 171 ± 28 M sun yr -1 , assuming a Salpeter-like initial mass function from 0.1 to 100 M sun yr -1 . The total IR luminosity derived using 70, 450, and 850 μm data is L IR = (5-10) x 10 11 L sun , corrected for gravitational lensing. This corresponds to ψ = 90-180 M sun yr -1 , where the upper range is consistent with that derived from the Paα luminosity. While the L(8 μm)/L(Paα) ratio is consistent with the extrapolated relation observed in local galaxies and star-forming regions, the rest-frame 24 μm luminosity is significantly lower with respect to local galaxies of comparable Paα luminosity. Thus, SMM J163554.2+661225 arguably lacks a warmer dust component (T D ∼ 70 K), which is associated with deeply embedded star formation, and which contrasts with local galaxies with comparable SFRs. Rather, the starburst in SMM J163554.2+661225 is consistent with star-forming local galaxies with intrinsic luminosities, L IR ∼ 10 10 L sun , but 'scaled up' by a factor of ∼10-100.

The SMM Model as a Boundary Value Problem Using the Discrete Diffusion Equation

Science.gov (United States)

Campbell, Joel

2007-01-01

A generalized single step stepwise mutation model (SMM) is developed that takes into account an arbitrary initial state to a certain partial difference equation. This is solved in both the approximate continuum limit and the more exact discrete form. A time evolution model is developed for Y DNA or mtDNA that takes into account the reflective boundary modeling minimum microsatellite length and the original difference equation. A comparison is made between the more widely known continuum Gaussian model and a discrete model, which is based on modified Bessel functions of the first kind. A correction is made to the SMM model for the probability that two individuals are related that takes into account a reflecting boundary modeling minimum microsatellite length. This method is generalized to take into account the general n-step model and exact solutions are found. A new model is proposed for the step distribution.

Micromachined Parts Advance Medicine, Astrophysics, and More

Science.gov (United States)

2015-01-01

In the mid-1990s, Marshall Space Flight Center awarded two SBIR contracts to Potomac Photonics, now based in Baltimore, for the development of computerized workstations capable of mass-producing tiny, intricate, diffractive optical elements. While the company has since discontinued the workstations, those contracts set the stage for Potomac Photonics to be a leader in the micromachining industry, where NASA remains one of its clients.

Surface-micromachined magnetic undulator with period length between 10  μm and 1 mm for advanced light sources

Directory of Open Access Journals (Sweden)

Jere Harrison

2012-07-01

Full Text Available A technological gap exists between the μm-scale wiggling periods achieved using electromagnetic waves of high intensity laser pulses and the mm scale of permanent-magnet and superconducting undulators. In the sub-mm range, surface-micromachined soft-magnetic micro-electro-mechanical system inductors with integrated solenoidal coils have already experimentally demonstrated 100 to 500 mT field amplitude across air gaps as large as 15  μm. Simulations indicate that magnetic fields as large as 1.5 T across 50  μm inductor gaps are feasible. A simple rearranging of the yoke and pole geometry allows for fabrication of 10+ cm long undulator structures with period lengths between 12.5  μm and 1 mm. Such undulators find application both in high average power spontaneous emission sources and, if used in combination with ultrahigh-brightness electron beams, could lead to the realization of low energy compact free-electron lasers. Challenges include electron energy broadening due to wakefields and Joule heating in the electromagnet.

On the frequency of star-forming galaxies in the vicinity of powerful AGNs: The case of SMM J04135+10277

Science.gov (United States)

Fogasy, J.; Knudsen, K. K.; Lagos, C. D. P.; Drouart, G.; Gonzalez-Perez, V.

2017-01-01

Context. In the last decade several massive molecular gas reservoirs were found SMM J04135+10277 (z = 2.84) and investigate the expected frequency of quasar-starburst galaxy pairs at high redshift using a cosmological galaxy formation model. Methods: We use archive data and new APEX ArTeMiS data to construct and model the spectral energy distribution of SMM J04135+10277 in order to determine its properties. We also carry out a comprehensive analysis of the cosmological galaxy formation model galform with the aim of characterising how typical the system of SMM J04135+10277 is and whether quasar-star-forming galaxy pairs may constitute an important stage in galaxy evolution. Finally, we compare our results to observations found in the literature at both large and small scales (1 Mpc-100 kpc). Results: The companion galaxy of SMM J04135+10277 is a heavily dust-obscured starburst galaxy with a median star formation rate (SFR) of 700 M⊙ yr-1, median dust mass of 5.1 × 109M⊙ and median dust luminosity of 9.3 × 1012L⊙. Our simulations, performed at z = 2.8, suggest that SMM J04135+10277 is not unique. In fact, at a distance of 108M⊙, and 0.3% have at least one highly star-forming companion (SFR> 100 M⊙ yr-1). Conclusions: Our results suggest that quasar-gas-rich companion galaxy systems are common phenomena in the early Universe and the high incidence of companions makes the study of such systems crucial to understand the growth and hierarchical build-up of galaxies and black holes.

Determining the solar-flare photospheric scale height from SMM gamma-ray measurements

Science.gov (United States)

Lingenfelter, Richard E.

1991-01-01

A connected series of Monte Carlo programs was developed to make systematic calculations of the energy, temporal and angular dependences of the gamma-ray line and neutron emission resulting from such accelerated ion interactions. Comparing the results of these calculations with the Solar Maximum Mission/Gamma Ray Spectrometer (SMM/GRS) measurements of gamma-ray line and neutron fluxes, the total number and energy spectrum of the flare-accelerated ions trapped on magnetic loops at the Sun were determined and the angular distribution, pitch angle scattering, and mirroring of the ions on loop fields were constrained. Comparing the calculations with measurements of the time dependence of the neutron capture line emission, a determination of the He-3/H ratio in the photosphere was also made. The diagnostic capabilities of the SMM/GRS measurements were extended by developing a new technique to directly determine the effective photospheric scale height in solar flares from the neutron capture gamma-ray line measurements, and critically test current atmospheric models in the flare region.

Development of a focused ion beam micromachining system

Energy Technology Data Exchange (ETDEWEB)

Pellerin, J.G.; Griffis, D.; Russell, P.E.

1988-12-01

Focused ion beams are currently being investigated for many submicron fabrication and analytical purposes. An FIB micromachining system consisting of a UHV vacuum system, a liquid metal ion gun, and a control and data acquisition computer has been constructed. This system is being used to develop nanofabrication and nanomachining techniques involving focused ion beams and scanning tunneling microscopes.

Effects of Laser Operating Parameters on Piezoelectric Substrates Micromachining with Picosecond Laser

Directory of Open Access Journals (Sweden)

Lamia EL Fissi

2014-12-01

Full Text Available Ten picoseconds (200 kHz ultrafast laser micro-structuring of piezoelectric substrates including AT-cut quartz, Lithium Niobate and Lithium Tantalate have been studied for the purpose of piezoelectric devices application ranging from surface acoustic wave devices, e.g., bandpass filters, to photonic devices such as optical waveguides and holograms. The study examines the impact of changing several laser parameters on the resulting microstructural shapes and morphology. The micromachining rate has been observed to be strongly dependent on the operating parameters, such as the pulse fluence, the scan speed and the scan number. The results specifically indicate that ablation at low fluence and low speed scan tends to form a U-shaped cross-section, while a V-shaped profile can be obtained by using a high fluence and a high scan speed. The evolution of surface morphology revealed that laser pulses overlap in a range around 93% for both Lithium Niobate (LiNbO3 and Lithium Tantalate (LiTaO3 and 98% for AT-cut quartz can help to achieve optimal residual surface roughness.

Sustainable Materials Management (SMM) Web Academy Webinar: The EPA's Food Recovery Challenge: Be an Endorser!

Science.gov (United States)

This is a webinar page for the Sustainable Management of Materials (SMM) Web Academy webinar titled Let’s WRAP (Wrap Recycling Action Program): Best Practices to Boost Plastic Film Recycling in Your Community

Sustainable Materials Management (SMM) Web Academy Webinar: Food Waste Reduction Alliance, a Unique Industry Collaboration

Science.gov (United States)

This is a webinar page for the Sustainable Management of Materials (SMM) Web Academy webinar titled Let’s WRAP (Wrap Recycling Action Program): Best Practices to Boost Plastic Film Recycling in Your Community

Comparison of hard X-ray spectra obtained by spectrometers on Hinotori and SMM and detection of 'superhot' component

Science.gov (United States)

Nitta, Nariaki

1988-01-01

Hard X-ray spectra in solar flares obtained by the broadband spectrometers aboard Hinotori and SMM are compared. Within the uncertainty brought about by assuming the typical energy of the background X-rays, spectra by the Hinotori spectrometer are usually consistent with those by the SMM spectrometer for flares in 1981. On the contrary, flares in 1982 persistently show 20-50-percent higher flux by Hinotori than by SMM. If this discrepancy is entirely attributable to errors in the calibration of energy ranges, the errors would be about 10 percent. Despite such a discrepancy in absolute flux, in the the decay phase of one flare, spectra revealed a hard X-ray component (probably a 'superhot' component) that could be explained neither by emission from a plasma at about 2 x 10 to the 7th K nor by a nonthermal power-law component. Imaging observations during this period show hard X-ray emission nearly cospatial with soft X-ray emission, in contrast with earlier times at which hard and soft X-rays come from different places.

Micromachined two dimensional resistor arrays for determination of gas parameters

NARCIS (Netherlands)

van Baar, J.J.J.; Verwey, Willem B.; Dijkstra, Mindert; Dijkstra, Marcel; Wiegerink, Remco J.; Lammerink, Theodorus S.J.; Krijnen, Gijsbertus J.M.; Elwenspoek, Michael Curt

A resistive sensor array is presented for two dimensional temperature distribution measurements in a micromachined flow channel. This allows simultaneous measurement of flow velocity and fluid parameters, like thermal conductivity, diffusion coefficient and viscosity. More general advantages of

Long-term variations in the gamma-ray background on SMM

Science.gov (United States)

Kurfess, J. D.; Share, G. H.; Kinzer, R. L.; Johnson, W. N.; Adams, J. H., Jr.

1989-01-01

Long-term temporal variations in the various components of the background radiation detected by the gamma-ray spectrometer on the Solar Maximum Mission are presented. The SMM gamma-ray spectrometer was launched in February, 1980 and continues to operate normally. The extended period of mission operations has provided a large data base in which it is possible to investigate a variety of environmental and instrumental background effects. In particular, several effects associated with orbital precession are introduced and discussed.

Micromachined ultrasonic droplet generator based on a liquid horn structure

Science.gov (United States)

Meacham, J. M.; Ejimofor, C.; Kumar, S.; Degertekin, F. L.; Fedorov, A. G.

2004-05-01

A micromachined ultrasonic droplet generator is developed and demonstrated for drop-on-demand fluid atomization. The droplet generator comprises a bulk ceramic piezoelectric transducer for ultrasound generation, a reservoir for the ejection fluid, and a silicon micromachined liquid horn structure as the nozzle. The nozzles are formed using a simple batch microfabrication process that involves wet etching of (100) silicon in potassium hydroxide solution. Device operation is demonstrated by droplet ejection of water through 30 μm orifices at 1.49 and 2.30 MHz. The finite-element simulations of the acoustic fields in the cavity and electrical impedance of the device are in agreement with the measurements and indicate that the device utilizes cavity resonances in the 1-5 MHz range in conjunction with acoustic wave focusing by the pyramidally shaped nozzles to achieve low power operation.

Femtosecond laser micro-machined polyimide films for cell scaffold applications

DEFF Research Database (Denmark)

Antanavičiute, Ieva; Šimatonis, Linas; Ulčinas, Orestas

2018-01-01

of commercially available 12.7 and 25.4μm thickness polyimide (PI) film was applied. Mechanical properties of the fabricated scaffolds, i.e. arrays of differently spaced holes, were examined via custom-built uniaxial micro-tensile testing and finite element method simulations. We demonstrate that experimental...... micro-tensile testing results could be numerically simulated and explained by two-material model, assuming that 2-6μm width rings around the holes possessed up to five times higher Young's modulus and yield stress compared with the rest of the laser intacted PI film areas of 'dog-bone'-shaped specimens......Engineering of sophisticated synthetic 3D scaffolds that allow controlling behaviour and location of the cells requires advanced micro/nano-fabrication techniques. Ultrafast laser micro-machining employing a 1030-nm wavelength Yb:KGW femtosecond laser and a micro-fabrication workstation for micro-machining...

An in-pipe mobile micromachine using fluid power. A mechanism adaptable to pipe diameters

International Nuclear Information System (INIS)

Yoshida, Kazuhiro; Yokota, Shinichi; Takahashi, Ken

2000-01-01

To realize micro maintenance robots for small diameter pipes of nuclear reactors and so on, high power in-pipe mobile micromachines have been required. The authors have proposed the bellows microactuator using fluid power and have tried to apply the actuators to in-pipe mobile micromachines. In the previous papers, some inchworm mobile machine prototypes with 25 mm in diameter are fabricated and the traveling performances are experimentally investigated. In this paper, to miniaturize the in-pipe mobile machine and to make it adaptable to pipe diameters, firstly, a simple rubber-tube actuator constrained with a coil-spring is proposed and the static characteristics are investigated. Secondly, a supporting mechanism which utilizes a toggle mechanism and is adaptable to pipe diameters is proposed and the supporting forces are investigated. Finally, an in-pipe mobile micromachine for pipe with 4 - 5 mm in diameter is fabricated and the maximum traveling velocity of 7 mm/s in both ahead and astern movements is experimentally verified. (author)

Damping control of micromachined lowpass mechanical vibration isolation filters using electrostatic actuation with electronic signal processing

Science.gov (United States)

Dean, Robert; Flowers, George; Sanders, Nicole; MacAllister, Ken; Horvath, Roland; Hodel, A. S.; Johnson, Wayne; Kranz, Michael; Whitley, Michael

2005-05-01

Some harsh environments, such as those encountered by aerospace vehicles and various types of industrial machinery, contain high frequency/amplitude mechanical vibrations. Unfortunately, some very useful components are sensitive to these high frequency mechanical vibrations. Examples include MEMS gyroscopes and resonators, oscillators and some micro optics. Exposure of these components to high frequency mechanical vibrations present in the operating environment can result in problems ranging from an increased noise floor to component failure. Passive micromachined silicon lowpass filter structures (spring-mass-damper) have been demonstrated in recent years. However, the performance of these filter structures is typically limited by low damping (especially if operated in near-vacuum environments) and a lack of tunability after fabrication. Active filter topologies, such as piezoelectric, electrostrictive-polymer-film and SMA have also been investigated in recent years. Electrostatic actuators, however, are utilized in many micromachined silicon devices to generate mechanical motion. They offer a number of advantages, including low power, fast response time, compatibility with silicon micromachining, capacitive position measurement and relative simplicity of fabrication. This paper presents an approach for realizing active micromachined mechanical lowpass vibration isolation filters by integrating an electrostatic actuator with the micromachined passive filter structure to realize an active mechanical lowpass filter. Although the electrostatic actuator can be used to adjust the filter resonant frequency, the primary application is for increasing the damping to an acceptable level. The physical size of these active filters is suitable for use in or as packaging for sensitive electronic and MEMS devices, such as MEMS vibratory gyroscope chips.

SMM AS A PROMISING WAY TO PROMOTE GOODS AND SERVICES IN THE RUSSIAN MARKET

Directory of Open Access Journals (Sweden)

Ms. Elena V. Chepukhalina

2016-06-01

Full Text Available In this article definition to SMM is given (Social Media Marketing, types and tools of social media are classified, the marketing tasks solved by social media are listed, and the Russian audience of users of social media is analysed.

Design and development of a surface micro-machined push–pull-type true-time-delay phase shifter on an alumina substrate for Ka-band T/R module application

International Nuclear Information System (INIS)

Dey, Sukomal; Koul, Shiban K

2012-01-01

A radio frequency micro-electro-mechanical system (RF-MEMS) phase shifter based on the distributed MEMS transmission line (DMTL) concept towards maximum achievable phase shift with low actuation voltage with good figure of merit (FOM) is presented in this paper. This surface micro-machined analog DMTL phase shifter demonstrates low power consumption for implementation in a Ka-band transmit/receive (T/R) module. The push–pull-type switch has been designed and optimized with an analytical method and validated with simulation, which is the fundamental building block of the design of a true-time-delay phase shifter. Change in phase has been designed and optimized in push and pull states with reference to the up-state performance of the phase shifter. The working principle of this push–pull-type DMTL phase shifter has been comprehensively worked out. A thorough detail of the design and performance analysis of the phase shifter has been carried out with various structural parameters using commercially available simulation tools with reference to a change in phase shift and has been verified using a system level simulation. The phase shifter is fabricated on the alumina substrate, using a suspended gold bridge membrane with a surface micromachining process. Asymmetric behaviour of push–pull bridge configuration has been noted and a corresponding effect on mechanical, electrical and RF performances has been extensively investigated. It is demonstrated 114° dB −1 FOM over 0–40 GHz band, which is the highest achievable FOM from a unit cell on an alumina substrate reported so far. A complete phase shifter contributes to a continuous differential phase shift of 0°–360° over 0–40 GHz band with a minimum actuation voltage of 8.1 V which is the highest achievable phase shift with the lowest actuation voltage as per till date on the alumina substrate with good repeatability and return loss better than 11.5 dB over 0–40 GHz band. (paper)

Calibration and combination of monthly near-surface temperature and precipitation predictions over Europe

Science.gov (United States)

Rodrigues, Luis R. L.; Doblas-Reyes, Francisco J.; Coelho, Caio A. S.

2018-02-01

A Bayesian method known as the Forecast Assimilation (FA) was used to calibrate and combine monthly near-surface temperature and precipitation outputs from seasonal dynamical forecast systems. The simple multimodel (SMM), a method that combines predictions with equal weights, was used as a benchmark. This research focuses on Europe and adjacent regions for predictions initialized in May and November, covering the boreal summer and winter months. The forecast quality of the FA and SMM as well as the single seasonal dynamical forecast systems was assessed using deterministic and probabilistic measures. A non-parametric bootstrap method was used to account for the sampling uncertainty of the forecast quality measures. We show that the FA performs as well as or better than the SMM in regions where the dynamical forecast systems were able to represent the main modes of climate covariability. An illustration with the near-surface temperature over North Atlantic, the Mediterranean Sea and Middle-East in summer months associated with the well predicted first mode of climate covariability is offered. However, the main modes of climate covariability are not well represented in most situations discussed in this study as the seasonal dynamical forecast systems have limited skill when predicting the European climate. In these situations, the SMM performs better more often.

Characterization and modeling of 2D-glass micro-machining by spark-assisted chemical engraving (SACE) with constant velocity

International Nuclear Information System (INIS)

Didar, Tohid Fatanat; Dolatabadi, Ali; Wüthrich, Rolf

2008-01-01

Spark-assisted chemical engraving (SACE) is an unconventional micro-machining technology based on electrochemical discharge used for micro-machining nonconductive materials. SACE 2D micro-machining with constant speed was used to machine micro-channels in glass. Parameters affecting the quality and geometry of the micro-channels machined by SACE technology with constant velocity were presented and the effect of each of the parameters was assessed. The effect of chemical etching on the geometry of micro-channels under different machining conditions has been studied, and a model is proposed for characterization of the micro-channels as a function of machining voltage and applied speed

High-frequency micro-machined power inductors

International Nuclear Information System (INIS)

Wang, N.; O'Donnell, T.; Roy, S.; Brunet, M.; McCloskey, P.; O'Mathuna, S.C.

2005-01-01

Power inductors have been fabricated on silicon substrates using low-temperature IC compatible processes. The electrical properties of these micro-inductors have been measured and discussed. A maximum quality factor of 6 at 4 MHz has been achieved with an inductance value of about 160 nH. The DC saturation currents of the non-gapped and gapped inductors are ∼500 and 700 mA, respectively. The relatively high Q factor and the load current characteristics allow these micro-machined inductors to be used in integrated power converters

Monitoring of yeast cell concentration using a micromachined impedance sensor

NARCIS (Netherlands)

Krommenhoek, E.E.; Gardeniers, Johannes G.E.; Bomer, Johan G.; van den Berg, Albert; Li, X.; Ottens, M.; van der Wielen, L.A.M.; van Dedem, G.W.K.; van Leeuwen, M.; van Gulik, W.M.; Heijnen, J.J.

2005-01-01

The paper describes the design, modelling and experimental characterization of a micromachined impedance sensor for on-line monitoring of the viable yeast cell concentration (biomass) in a miniaturized cell assay. Measurements in a Saccharomyces cerevisiae cell culture show that the permittivity of

Laser micromachining of biofactory-on-a-chip devices

Science.gov (United States)

Burt, Julian P.; Goater, Andrew D.; Hayden, Christopher J.; Tame, John A.

2002-06-01

Excimer laser micromachining provides a flexible means for the manufacture and rapid prototyping of miniaturized systems such as Biofactory-on-a-Chip devices. Biofactories are miniaturized diagnostic devices capable of characterizing, manipulating, separating and sorting suspension of particles such as biological cells. Such systems operate by exploiting the electrical properties of microparticles and controlling particle movement in AC non- uniform stationary and moving electric fields. Applications of Biofactory devices are diverse and include, among others, the healthcare, pharmaceutical, chemical processing, environmental monitoring and food diagnostic markets. To achieve such characterization and separation, Biofactory devices employ laboratory-on-a-chip type components such as complex multilayer microelectrode arrays, microfluidic channels, manifold systems and on-chip detection systems. Here we discuss the manufacturing requirements of Biofactory devices and describe the use of different excimer laser micromachined methods both in stand-alone processes and also in conjunction with conventional fabrication processes such as photolithography and thermal molding. Particular attention is given to the production of large area multilayer microelectrode arrays and the manufacture of complex cross-section microfluidic channel systems for use in simple distribution and device interfacing.

Electronic structure of surface-supported bis(phthalocyaninato) terbium(III) single molecular magnets.

Science.gov (United States)

Vitali, Lucia; Fabris, Stefano; Conte, Adriano Mosca; Brink, Susan; Ruben, Mario; Baroni, Stefano; Kern, Klaus

2008-10-01

The electronic structure of isolated bis(phthalocyaninato) terbium(III) molecules, a novel single-molecular-magnet (SMM), supported on the Cu(111) surface has been characterized by density functional theory and scanning tunneling spectroscopy. These studies reveal that the interaction with the metal surface preserves both the molecular structure and the large spin magnetic moment of the metal center. The 4f electron states are not perturbed by the adsorption while a strong molecular/metal interaction can induce the suppression of the minor spin contribution delocalized over the molecular ligands. The calculations show that the inherent spin magnetic moment of the molecule is only weakly affected by the interaction with the surface and suggest that the SMM character might be preserved.

Micromachined millimeter-wave photonic band-gap crystals

International Nuclear Information System (INIS)

Oezbay, E.; Michel, E.; Tuttle, G.; Biswas, R.; Sigalas, M.; Ho, K.

1994-01-01

We have developed a new technique for fabricating three-dimensional photonic band-gap crystals. Our method utilizes an orderly stacking of micromachined (110) silicon wafers to build the periodic structure. A structure with a full three-dimensional photonic band gap centered near 100 GHz was measured, with experimental results in good agreement with theoretical predictions. This basic approach described should be extendable to build structures with photonic band-gap frequencies ranging from 30 GHz to 3 THz

Fiscal 1997 report on technological results. R and D on micromachine technology; 1997 nendo micromachine gijutsu no kenkyu kaihatsu seika hokokusho

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-03-01

Researches on basic element technology of micromachines are conducted that operate autonomously in a narrow small part in a complicated apparatus or in vivo. The areas of activity are 1. research on micromachine systems and 2. comprehensive investigation and research. In 1, (1) a micro catheter and (2) a micro tactile sensor catheter were studied while, in 2, basic technology and technological problems, particularly those problems concerning sophistication in the medical field were examined and studied. Further, in (1), with the purpose of developing a micro laser catheter for diagnosis/treatment, researches were implemented on the technology of integrating micro laser and an optical fiber which were components of the catheter and on the fabrication of the fine diameter of a micro catheter as well as on the characteristical improvement of the base body on which minute elements were mounted. In (2), characteristical improvement and sophistication were carried out for a high sensitivity contact pressure sensor and a diagnostic tactile sensor, which are mounted on a catheter having a positive bulge control mechanism for insertion into body cavity, with a sensor probe manufactured experimentally. (NEDO)

Development of a Novel Transparent Flexible Capacitive Micromachined Ultrasonic Transducer

Directory of Open Access Journals (Sweden)

Da-Chen Pang

2017-06-01

Full Text Available This paper presents the world’s first transparent flexible capacitive micromachined ultrasonic transducer (CMUT that was fabricated through a roll-lamination technique. This polymer-based CMUT has advantages of transparency, flexibility, and non-contacting detection which provide unique functions in display panel applications. Comprising an indium tin oxide-polyethylene terephthalate (ITO-PET substrate, SU-8 sidewall and vibrating membranes, and silver nanowire transparent electrode, the transducer has visible-light transmittance exceeding 80% and can operate on curved surfaces with a 40 mm radius of curvature. Unlike the traditional silicon-based high temperature process, the CMUT can be fabricated on a flexible substrate at a temperature below 100 °C to reduce residual stress introduced at high temperature. The CMUT on the curved surfaces can detect a flat target and finger at distances up to 50 mm and 40 mm, respectively. The transparent flexible CMUT provides a better human-machine interface than existing touch panels because it can be integrated with a display panel for non-contacting control in a health conscious environment and the flexible feature is critical for curved display and wearable electronics.

Sustainable Materials Management (SMM) Web Academy Webinar: Managing Wasted Food with Anaerobic Digestion: Incentives and Innovations

Science.gov (United States)

This is a webinar page for the Sustainable Management of Materials (SMM) Web Academy webinar titled Let’s WRAP (Wrap Recycling Action Program): Best Practices to Boost Plastic Film Recycling in Your Community

Modelling the magnetic behaviour of square-pyramidal Co(II)5 aggregates: tuning SMM behaviour through variations in the ligand shell.

Science.gov (United States)

Klöwer, Frederik; Lan, Yanhua; Nehrkorn, Joscha; Waldmann, Oliver; Anson, Christopher E; Powell, Annie K

2009-07-27

Three new mu4-bridged Co(II)5 clusters with similar core motifs have been synthesised with the use of N-tert-butyldiethanolamine (tbdeaH2) and pivalic acid (piv): [Co(II)5(mu4-N3)(tbdea)2(mu-piv)4(piv)(CH3CN)2].CH3CN (1), [Co(II)5(mu4-Cl)(Cl)(tbdea)2(mu-piv)4(pivH)2] (2) and [Co(II)5(mu4-N3)(Cl)(tbdea)2(mu-piv)4(pivH)2] (3). Magnetic measurements were performed for all three compounds. It was found that while the chloride-bridged cluster 2 does not show an out-of-phase signal, which excludes single-molecule magnet (SMM) behaviour, the azide-bridged compounds 1 and 3 show out-of-phase signals as well as frequency dependence of the ac susceptibility, as expected for SMMs. We confirmed that 1 is a SMM with zero-field quantum tunnelling of the magnetisation at 1.8 K. Compound 3 is likely a SMM with a blocking temperature well below 1.8 K. We established a physical model to fit the chiT versus T and M versus B curves of the three compounds to reproduce the observed SMM trend. The analysis showed that small changes in the ligand shell modify not only the magnitude of exchange constants, but also affect the J and g matrices in a non-trivial way.

Optofluidic Microlasers based on Femtosecond Micromachining Technology

Directory of Open Access Journals (Sweden)

Simoni F.

2017-08-01

Full Text Available We present the different optofluidic lasers which have been realized using the Femtosecond Micromachining technique to fabricate the monolithic optofluidic structures in glass chips. We show how the great flexibility of this 3D technique allows getting different kind of optical cavities. The most recent devices fabricated by this technique as ring shaped and Fabry-Perot resonators show excellent emission performances.We also point out how the addition of the inkjet printing technique provides further opportunities in realizing optofluidic chips.

Improving the Design of Capacitive Micromachined Ultrasonic Transducers Aided with Sensitivity Analysis

Directory of Open Access Journals (Sweden)

A Martowicz

2016-09-01

Full Text Available The paper presents the results of analysis performed to search for feasible design improvements for capacitive micromachined ultrasonic transducer. Carried out search has been aided with the sensitivity analysis and the application of Response Surface Method. The multiphysics approach has been taken into account in elaborated finite element model of one cell of described transducer in order to include significant physical phenomena present in modelled microdevice. The set of twelve input uncertain and design parameters consists of geometric, material and control properties. The amplitude of dynamic membrane deformation of the transducer has been chosen as studied parameter. The objective of performed study has been defined as the task of finding robust design configurations of the transducer, i.e. characterizing maximal value of deformation amplitude with its minimal variation.

Femtosecond laser micromachining of polylactic acid/graphene composites for designing interdigitated microelectrodes for sensor applications

Science.gov (United States)

Paula, Kelly T.; Gaál, Gabriel; Almeida, G. F. B.; Andrade, M. B.; Facure, Murilo H. M.; Correa, Daniel S.; Riul, Antonio; Rodrigues, Varlei; Mendonça, Cleber R.

2018-05-01

There is an increasing interest in the last years towards electronic applications of graphene-based materials and devices fabricated from patterning techniques, with the ultimate goal of high performance and temporal resolution. Laser micromachining using femtosecond pulses is an attractive methodology to integrate graphene-based materials into functional devices as it allows changes to the focal volume with a submicrometer spatial resolution due to the efficient nonlinear nature of the absorption, yielding rapid prototyping for innovative applications. We present here the patterning of PLA-graphene films spin-coated on a glass substrate using a fs-laser at moderate pulse energies to fabricate interdigitated electrodes having a minimum spatial resolution of 5 μm. Raman spectroscopy of the PLA-graphene films indicated the presence of multilayered graphene fibers. Subsequently, the PLA-graphene films were micromachined using a femtosecond laser oscillator delivering 50-fs pulses and 800 nm, where the pulse energy and scanning speed was varied in order to determine the optimum irradiation parameters (16 nJ and 100 μm/s) to the fabrication of microstructures. The micromachined patterns were characterized by optical microscopy and submitted to electrical measurements in liquid samples, clearly distinguishing all tastes tested. Our results confirm the femtosecond laser micromachining technique as an interesting approach to efficiently pattern PLA-graphene filaments with high precision and minimal mechanical defects, allowing the easy fabrication of interdigitated structures and an alternative method to those produced by conventional photolithography.

Femtosecond laser micromachining of compound parabolic concentrator fiber tipped glucose sensors

DEFF Research Database (Denmark)

Hassan, Hafeez Ul; Lacraz, Amédée; Kalli, Kyriacos

2017-01-01

We report on highly accurate femtosecond (fs) laser micromachining of a compound parabolic concentrator (CPC) fiber tip on a polymer optical fiber (POF). The accuracy is reflected in an unprecedented correspondence between the numerically predicted and experimentally found improvement in fluoresc...

Solid polymer electrolyte composite membrane comprising laser micromachined porous support

Science.gov (United States)

Liu, Han [Waltham, MA; LaConti, Anthony B [Lynnfield, MA; Mittelsteadt, Cortney K [Natick, MA; McCallum, Thomas J [Ashland, MA

2011-01-11

A solid polymer electrolyte composite membrane and method of manufacturing the same. According to one embodiment, the composite membrane comprises a rigid, non-electrically-conducting support, the support preferably being a sheet of polyimide having a thickness of about 7.5 to 15 microns. The support has a plurality of cylindrical pores extending perpendicularly between opposing top and bottom surfaces of the support. The pores, which preferably have a diameter of about 5 microns, are made by laser micromachining and preferably are arranged in a defined pattern, for example, with fewer pores located in areas of high membrane stress and more pores located in areas of low membrane stress. The pores are filled with a first solid polymer electrolyte, such as a perfluorosulfonic acid (PFSA) polymer. A second solid polymer electrolyte, which may be the same as or different than the first solid polymer electrolyte, may be deposited over the top and/or bottom of the first solid polymer electrolyte.

Determination of solar flare accelerated ion angular distributions from SMM gamma ray and neutron measurements and determination of the He-3/H ratio in the solar photosphere from SMM gamma ray measurements

Science.gov (United States)

Lingenfelter, Richard E.

1989-01-01

Comparisons of Solar Maximum Mission (SMM) observations of gamma-ray line and neutron emission with theoretical calculation of their expected production by flare accelerated ion interactions in the solar atmosphere have led to significant advances in the understanding of solar flare particle acceleration and interaction, as well as the flare process itself. These comparisons have enabled the determination of, not only the total number and energy spectrum of accelerated ions trapped at the sun, but also the ion angular distribution as they interact in the solar atmosphere. The Monte Carlo program was modified to include in the calculations of ion trajectories the effects of both mirroring in converging magnetic fields and of pitch angle scattering. Comparing the results of these calculations with the SMM observations, not only the angular distribution of the interacting ions can be determined, but also the initial angular distribution of the ions at acceleration. The reliable determination of the solar photospheric He-3 abundance is of great importance for understanding nucleosynthesis in the early universe and its implications for cosmology, as well as for the study of the evolution of the sun. It is also essential for the determinations of the spectrum and total number of flare accelerated ions from the SMM/GRS gamma-ray line measurements. Systematic Monte Carlo calculations of the time dependence were made as a function of the He-3 abundance and other variables. A new series of calculations were compared for the time-dependent flux of 2.223 MeV neutron capture line emission and the ratio of the time-integrated flux in the 2.223 MeV line to that in the 4.1 to 6.4 MeV nuclear deexcitation band.

Prediction of MHC class II binding affinity using SMM-align, a novel stabilization matrix alignment method

DEFF Research Database (Denmark)

Nielsen, Morten; Lundegaard, Claus; Lund, Ole

2007-01-01

the correct alignment of a peptide in the binding groove a crucial part of identifying the core of an MHC class II binding motif. Here, we present a novel stabilization matrix alignment method, SMM-align, that allows for direct prediction of peptide:MHC binding affinities. The predictive performance...... of the method is validated on a large MHC class II benchmark data set covering 14 HLA-DR (human MHC) and three mouse H2-IA alleles. RESULTS: The predictive performance of the SMM-align method was demonstrated to be superior to that of the Gibbs sampler, TEPITOPE, SVRMHC, and MHCpred methods. Cross validation...... between peptide data set obtained from different sources demonstrated that direct incorporation of peptide length potentially results in over-fitting of the binding prediction method. Focusing on amino terminal peptide flanking residues (PFR), we demonstrate a consistent gain in predictive performance...

Study of ablation on surfaces of nuclear-use metals irradiated with Femtosecond laser

International Nuclear Information System (INIS)

Nogueira, Alessandro F.; Samad, Ricardo E.; Vieira Junior, Nilson D.; Rossi, Wagner de

2017-01-01

The use of ultrashort pulsed lasers is an alternative for micro-machining in metal surfaces, with diverse applications in several industrial areas, such as aeronautics, aerospace, naval, nuclear, among others, where there is a growing concern with reliability in service. In this work, micro-machining were performed on titanium surfaces using femtosecond ultrashort pulses. Such a process resulted in minimal heat transfer to the material, thus avoiding and surface deformation of the titanium plate and the formation of resolidified material in the ablated region, which are drawbacks present in the use of the long pulsed keyed laser of the order of nanoseconds. Three types of micro-machining were performed, with variations in the distances between the machined lines. It was also verified that the wettability increases when there is an increase in the distance between machined lines. Finally, in order to change the surface with minimal removal of material, it has been found that the use of ultra-short pulse lasers provide great benefits for the integrity of the ablated material. This initial study is the starting point for the study of other metals, such as Maraging Steels and Zircaloy that will be the target of future work. (author)

Study of ablation on surfaces of nuclear-use metals irradiated with Femtosecond laser

Energy Technology Data Exchange (ETDEWEB)

Nogueira, Alessandro F.; Samad, Ricardo E.; Vieira Junior, Nilson D.; Rossi, Wagner de, E-mail: alessandro.nogueira@usp.br, E-mail: resamad@ipen.br [Centro Tecnologico da Marinha em Sao Paulo (CTMSP), Sorocaba, SP (Brazil); Faculdade de Engenharia de Sorocaba (FACENS), Ipero, SP (Brazil); Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2017-11-01

The use of ultrashort pulsed lasers is an alternative for micro-machining in metal surfaces, with diverse applications in several industrial areas, such as aeronautics, aerospace, naval, nuclear, among others, where there is a growing concern with reliability in service. In this work, micro-machining were performed on titanium surfaces using femtosecond ultrashort pulses. Such a process resulted in minimal heat transfer to the material, thus avoiding and surface deformation of the titanium plate and the formation of resolidified material in the ablated region, which are drawbacks present in the use of the long pulsed keyed laser of the order of nanoseconds. Three types of micro-machining were performed, with variations in the distances between the machined lines. It was also verified that the wettability increases when there is an increase in the distance between machined lines. Finally, in order to change the surface with minimal removal of material, it has been found that the use of ultra-short pulse lasers provide great benefits for the integrity of the ablated material. This initial study is the starting point for the study of other metals, such as Maraging Steels and Zircaloy that will be the target of future work. (author)

Recent results on celestial gamma radiation from SMM

Science.gov (United States)

Share, Gerald H.

1991-01-01

Observations made by the Gamma Ray Spectrometer on board the SMM are described. Recent results reported include observations and analyses of gamma-ray lines from Co-56 produced in supernovae, observations of the temporal variation of the 511 keV line observed during Galactic center transits, and measurements of the diffuse Galactic spectrum from 0.3 to 8.5 MeV. The work in progress includes measurements of the distribution of Galactic Al-26, observations to place limits on Galactic Ti-44 and Fe-60 and on Be-7 produced in novae, and searches for a characteristic gamma-ray emission from pair plasmas, a 2.223 MeV line emission, limits on deexcitation lines from interstellar C and O, and gamma-ray bursts.

Sub 100 nm proton beam micromachining: theoretical calculations on resolution limits

International Nuclear Information System (INIS)

Kan, J.A. van; Sum, T.C.; Osipowicz, T.; Watt, F.

2000-01-01

Proton beam micromachining is a novel direct-write process for the production of three-dimensional (3D) microstructures. A focused beam of MeV protons is scanned in a pre-determined pattern over a suitable resist material (e.g. PMMA or SU-8) and the latent image formed is subsequently developed chemically. In this paper calculations on theoretical resolution limits of proton beam micromachined three-dimensional microstructures are presented. Neglecting the finite beam size, a Monte Carlo ion transport code was used in combination with a theoretical model describing the delta-ray (δ-ray) energy deposition to determine the lateral energy deposition distribution in PMMA resist material. The energy deposition distribution of ion induced secondary electrons (δ-rays) has been parameterized using analytical models. It is assumed that the attainable resolution is limited by a convolution of the spread of the ion beam and energy deposition of the δ-rays

CoMStOC vs. International Solar Month - Experience gained and lessons learned from SMM campaigns

Science.gov (United States)

Schmelz, J. T.

1991-01-01

The factors that should be addressed by the organizers of a solar observing campaign are outlined and described. Two recent solar observing campaigns are compared and discussed. Lessons learned from these and other campaigns involving the SMM satellite are analyzed and advice for future campaigns is offered.

Fabrication and Characterization of Capacitive Micromachined Ultrasonic Transducers with Low-Temperature Wafer Direct Bonding

Directory of Open Access Journals (Sweden)

Xiaoqing Wang

2016-12-01

Full Text Available This paper presents a fabrication method of capacitive micromachined ultrasonic transducers (CMUTs by wafer direct bonding, which utilizes both the wet chemical and O2plasma activation processes to decrease the bonding temperature to 400 °C. Two key surface properties, the contact angle and surface roughness, are studied in relation to the activation processes, respectively. By optimizing the surface activation parameters, a surface roughness of 0.274 nm and a contact angle of 0° are achieved. The infrared images and static deflection of devices are assessed to prove the good bonding effect. CMUTs having silicon membranes with a radius of 60 μm and a thickness of 2 μm are fabricated. Device properties have been characterized by electrical and acoustic measurements to verify their functionality and thus to validate this low-temperature process. A resonant frequency of 2.06 MHz is obtained by the frequency response measurements. The electrical insertion loss and acoustic signal have been evaluated. This study demonstrates that the CMUT devices can be fabricated by low-temperature wafer direct bonding, which makes it possible to integrate them directly on top of integrated circuit (IC substrates.

Silicon-micromachined microchannel plates

CERN Document Server

Beetz, C P; Steinbeck, J; Lemieux, B; Winn, D R

2000-01-01

Microchannel plates (MCP) fabricated from standard silicon wafer substrates using a novel silicon micromachining process, together with standard silicon photolithographic process steps, are described. The resulting SiMCP microchannels have dimensions of approx 0.5 to approx 25 mu m, with aspect ratios up to 300, and have the dimensional precision and absence of interstitial defects characteristic of photolithographic processing, compatible with positional matching to silicon electronics readouts. The open channel areal fraction and detection efficiency may exceed 90% on plates up to 300 mm in diameter. The resulting silicon substrates can be converted entirely to amorphous quartz (qMCP). The strip resistance and secondary emission are developed by controlled depositions of thin films, at temperatures up to 1200 deg. C, also compatible with high-temperature brazing, and can be essentially hydrogen, water and radionuclide-free. Novel secondary emitters and cesiated photocathodes can be high-temperature deposite...

A novel micromachined shadow mask system with self-alignment and gap control capability

International Nuclear Information System (INIS)

Hong, Jung Moo; Zou Jun

2008-01-01

We present a novel micromachined shadow mask system, which is capable of accurate self-alignment and mask-substrate gap control. The shadow mask system consists of a silicon shadow mask and a silicon carrier wafer with pyramidal cavities fabricated with bulk micromachining. Self-alignment and gap control of the shadow mask and the fabrication substrate can readily be achieved by using matching pairs of pyramidal cavities and steel spheres placed between. The layer-to-layer alignment accuracy of the new shadow mask system has been experimentally characterized and verified using both optical and atomic force microscopic measurements. As an application of this new shadow mask system, an organic thin-film transistor (OTFT) using pentacene as the semiconductor layer has been successfully fabricated and tested

Numerical modelling of micro-machining of f.c.c. single crystal: Influence of strain gradients

KAUST Repository

Demiral, Murat

2014-11-01

A micro-machining process becomes increasingly important with the continuous miniaturization of components used in various fields from military to civilian applications. To characterise underlying micromechanics, a 3D finite-element model of orthogonal micro-machining of f.c.c. single crystal copper was developed. The model was implemented in a commercial software ABAQUS/Explicit employing a user-defined subroutine VUMAT. Strain-gradient crystal-plasticity and conventional crystal-plasticity theories were used to demonstrate the influence of pre-existing and evolved strain gradients on the cutting process for different combinations of crystal orientations and cutting directions. Crown Copyright © 2014.

Manufacture of Radio Frequency Micromachined Switches with Annealing

OpenAIRE

Lin, Cheng-Yang; Dai, Ching-Liang

2014-01-01

The fabrication and characterization of a radio frequency (RF) micromachined switch with annealing were presented. The structure of the RF switch consists of a membrane, coplanar waveguide (CPW) lines, and eight springs. The RF switch is manufactured using the complementary metal oxide semiconductor (CMOS) process. The switch requires a post-process to release the membrane and springs. The post-process uses a wet etching to remove the sacrificial silicon dioxide layer, and to obtain the suspe...

Ultrafast disk technology enables next generation micromachining laser sources

Science.gov (United States)

Heckl, Oliver H.; Weiler, Sascha; Luzius, Severin; Zawischa, Ivo; Sutter, Dirk

2013-02-01

Ultrashort pulsed lasers based on thin disk technology have entered the 100 W regime and deliver several tens of MW peak power without chirped pulse amplification. Highest uptime and insensitivity to back reflections make them ideal tools for efficient and cost effective industrial micromachining. Frequency converted versions allow the processing of a large variety of materials. On one hand, thin disk oscillators deliver more than 30 MW peak power directly out of the resonator in laboratory setups. These peak power levels are made possible by recent progress in the scaling of the pulse energy in excess of 40 μJ. At the corresponding high peak intensity, thin disk technology profits from the limited amount of material and hence the manageable nonlinearity within the resonator. Using new broadband host materials like for example the sesquioxides will eventually reduce the pulse duration during high power operation and further increase the peak power. On the other hand industry grade amplifier systems deliver even higher peak power levels. At closed-loop controlled 100W, the TruMicro Series 5000 currently offers the highest average ultrafast power in an industry proven product, and enables efficient micromachining of almost any material, in particular of glasses, ceramics or sapphire. Conventional laser cutting of these materials often requires UV laser sources with pulse durations of several nanoseconds and an average power in the 10 W range. Material processing based on high peak power laser sources makes use of multi-photon absorption processes. This highly nonlinear absorption enables micromachining driven by the fundamental (1030 nm) or frequency doubled (515 nm) wavelength of Yb:YAG. Operation in the IR or green spectral range reduces the complexity and running costs of industrial systems initially based on UV light sources. Where UV wavelength is required, the TruMicro 5360 with a specified UV crystal life-time of more than 10 thousand hours of continues

Gamma ray detector for solar maximum mission (SMM) of NASA

International Nuclear Information System (INIS)

Brunner, W.; Brichzin, K.; Sach, E.

1981-06-01

For NASA's Project Solar Maximum Mission-SMM (launch 14.2.80) a Gamma Ray Detector was developed, manufactured and tested to measure solar high energetic Gamma rays and Neutron fluxes within the energy range 10-160 MeV, 4,43 MeV amd 2,23 MeV. The main components of the sensor are 7 NaI crystals 3 x 3 and a CsI crystal 30 cm diameter x 7,5 cm. The rejection of charged particles is done by two plasitc scintillators and 4 CsI-shields. From the beginning of the mission the experiment is working fully successfull. (orig.) [de

Steady flows in the solar transition region observed with SMM

International Nuclear Information System (INIS)

Gebbie, K.B.; Hill, F.; Toomre, J.; November, L.J.; Simon, G.W.; Gurman, J.B.; Shine, R.A.; Woodgate, B.E.; Athay, R.G.; Bruner, E.C. Jr.; Rehse, R.A.; Tandberg-Hanssen, E.A.

1981-01-01

Steady flows in the quiet solar transition region have been observed with the Ultraviolet Spectrometer and Polarimeter (UVSP) experiment on the Solar Maximum Mission (SMM) satellite. The persistent vertical motions seen at disk center have spatial rms amplitudes of 1.4 km s -1 in the C II line, 3.9 km s -1 in Si IV, and 4.2 km s -1 in C IV. The amplitudes of the more horizontal flows seen toward the limb tend to be somewhat higher. Plots of steady vertical velocity versus intensity seen at disk center in Si IV and C IV show two distinct branches

Optimized design of micromachined electric field mills to maximize electrostatic field sensitivity

Directory of Open Access Journals (Sweden)

Yu Zhou

2016-07-01

Full Text Available This paper describes the design optimization of a micromachined electric field mill, in relation to maximizing its output signal. The cases studied are for a perforated electrically grounded shutter vibrating laterally over sensing electrodes. It is shown that when modeling the output signal of the sensor, the differential charge on the sense electrodes when exposed to vs. visibly shielded from the incident electric field must be considered. Parametric studies of device dimensions show that the shutter thickness and its spacing from the underlying electrodes should be minimized as these parameters very strongly affect the MEFM signal. Exploration of the shutter perforation size and sense electrode width indicate that the best MEFM design is one where shutter perforation widths are a few times larger than the sense electrode widths. Keywords: MEFM, Finite element method, Electric field measurement, MEMS, Micromachining

Micromachined single-level nonplanar polycrystalline SiGe thermal microemitters for infrared dynamic scene projection

Science.gov (United States)

Malyutenko, V. K.; Malyutenko, O. Yu.; Leonov, V.; Van Hoof, C.

2009-05-01

The technology for self-supported membraneless polycrystalline SiGe thermal microemitters, their design, and performance are presented. The 128-element arrays with a fill factor of 88% and a 2.5-μm-thick resonant cavity have been grown by low-pressure chemical vapor deposition and fabricated using surface micromachining technology. The 200-nm-thick 60×60 μm2 emitting pixels enforced with a U-shape profile pattern demonstrate a thermal time constant of 2-7 ms and an apparent temperature of 700 K in the 3-5 and 8-12 μm atmospheric transparency windows. The application of the devices to the infrared dynamic scene simulation and their benefit over conventional planar membrane-supported emitters are discussed.

Tropical behavior of mesospheric ozone as observed by SMM

Science.gov (United States)

Aikin, A. C.; Kendig, D. J.

1992-01-01

The seasonal behavior of low latitude mesospheric ozone, as observed by the SMM satellite solar occultation experiment, is detailed for the 1985-1989 period. Annual as well as semi-annual waves are observed in the 50-70 km altitude region. In the latitude range of +/- 30 deg the ozone phase and amplitude are functions of temperature and seasonal changes in solar flux. Temperature is the controlling factor for the equatorial region and seasonal changes in solar flux become more dominant at latitudes outside the equatorial zone (greater than +/- 15 deg). There is a hemispheric asymmetry in the ozone annual wave in the 20-30 deg region, with Northern Hemispheric ozone having a larger amplitude than Southern Hemispheric ozone.

Optimization of design parameters for bulk micromachined silicon membranes for piezoresistive pressure sensing application

International Nuclear Information System (INIS)

Belwanshi, Vinod; Topkar, Anita

2016-01-01

Finite element analysis study has been carried out to optimize the design parameters for bulk micro-machined silicon membranes for piezoresistive pressure sensing applications. The design is targeted for measurement of pressure up to 200 bar for nuclear reactor applications. The mechanical behavior of bulk micro-machined silicon membranes in terms of deflection and stress generation has been simulated. Based on the simulation results, optimization of the membrane design parameters in terms of length, width and thickness has been carried out. Subsequent to optimization of membrane geometrical parameters, the dimensions and location of the high stress concentration region for implantation of piezoresistors have been obtained for sensing of pressure using piezoresistive sensing technique.

Optimization of design parameters for bulk micromachined silicon membranes for piezoresistive pressure sensing application

Science.gov (United States)

Belwanshi, Vinod; Topkar, Anita

2016-05-01

Finite element analysis study has been carried out to optimize the design parameters for bulk micro-machined silicon membranes for piezoresistive pressure sensing applications. The design is targeted for measurement of pressure up to 200 bar for nuclear reactor applications. The mechanical behavior of bulk micro-machined silicon membranes in terms of deflection and stress generation has been simulated. Based on the simulation results, optimization of the membrane design parameters in terms of length, width and thickness has been carried out. Subsequent to optimization of membrane geometrical parameters, the dimensions and location of the high stress concentration region for implantation of piezoresistors have been obtained for sensing of pressure using piezoresistive sensing technique.

Bending-induced electromechanical coupling and large piezoelectric response in a micromachined diaphragm

KAUST Repository

Wang, Zhihong; Yao, Yingbang; Wang, Xianbin; Yue, Weisheng; Chen, Longqing; Zhang, Xixiang

2013-01-01

We investigated the dependence of electromechanical coupling and the piezoelectric response of a micromachined Pb(Zr 0.52 Ti 0.48)O 3 (PZT) diaphragm on its curvature by observing the impedance spectrum and central deflection responses to a small AC

Sensitivity of Micromachined Joule-Thomson Cooler to Clogging Due to Moisture

NARCIS (Netherlands)

Cao, Haishan; Vanapalli, Srinivas; Holland, Herman J.; Vermeer, Cristian Hendrik; ter Brake, Hermanus J.M.

2015-01-01

A major issue in long-term operation of micromachined Joule-Thomson coolers is the clogging of the microchannels and/or the restriction due to the deposition of water molecules present in the working fluid. In this study, we present the performance of a microcooler operated with nitrogen gas with

Micromachined Microwave Cavity Resonator Filters for 5G: a Feasibility Study

NARCIS (Netherlands)

Kemenade, van R.; Smolders, A.B.; Hon, de B.P.

2015-01-01

Micromachined microwave cavity filters offer a light-weight, high-Q and highly integrated alternative in the frequency range of 20 GHz–100 GHz as compared to conventional filter types. The filter technology shows potential for use in 5G portable devices and as such, the design of a duplexer

Arrayed architectures for multi-stage Si-micromachined high-flow Knudsen pumps

International Nuclear Information System (INIS)

Qin, Yutao; An, Seungdo; Gianchandani, Yogesh B

2015-01-01

This paper reports an evaluation and a comparison of two architectures for implementing Si-micromachined high-flow Knudsen pumps. Knudsen pumps, which operate on the principle of thermal transpiration, have been shown to have great promise for micro-scale gas phase fluidic systems such as micro gas chromatographs. Simultaneously achieving both a high flow rate and adequate blocking pressure has been a persistent challenge, which is addressed in this work by combining multiple pumps in series and addressing the resulting challenges in thermal management. The basic building block is a Si-micromachined pump with  ≈100 000 parallel channels in a 4 mm  ×  6 mm footprint. In the primary approach, multiple pump stages are stacked vertically with interleaved Si-micromachined spacers. A stacked 4-stage Knudsen pump has a form factor of 10 mm  ×  8 mm  ×  6 mm. In an alternate approach, multiple stages are arranged in a planar array. The experimental results demonstrate multiplication of the output pressure head with the number of stages, while the flow rate is maintained. For example, a stacked 4-stage Knudsen pump with 8 W power operated at atmospheric pressure provided a blocking pressure of 0.255 kPa, which was 3.6  ×  of that provided by a single-stage pump with 2 W power; while both provided a  ≈  30 sccm maximum flow rate. The performance can be customized for practical applications such as micro gas chromatography. (paper)

Biasing of Capacitive Micromachined Ultrasonic Transducers.

Science.gov (United States)

Caliano, Giosue; Matrone, Giulia; Savoia, Alessandro Stuart

2017-02-01

Capacitive micromachined ultrasonic transducers (CMUTs) represent an effective alternative to piezoelectric transducers for medical ultrasound imaging applications. They are microelectromechanical devices fabricated using silicon micromachining techniques, developed in the last two decades in many laboratories. The interest for this novel transducer technology relies on its full compatibility with standard integrated circuit technology that makes it possible to integrate on the same chip the transducers and the electronics, thus enabling the realization of extremely low-cost and high-performance devices, including both 1-D or 2-D arrays. Being capacitive transducers, CMUTs require a high bias voltage to be properly operated in pulse-echo imaging applications. The typical bias supply residual ripple of high-quality high-voltage (HV) generators is in the millivolt range, which is comparable with the amplitude of the received echo signals, and it is particularly difficult to minimize. The aim of this paper is to analyze the classical CMUT biasing circuits, highlighting the features of each one, and to propose two novel HV generator architectures optimized for CMUT biasing applications. The first circuit proposed is an ultralow-residual ripple (generator that uses an extremely stable sinusoidal power oscillator topology. The second circuit employs a commercially available integrated step-up converter characterized by a particularly efficient switching topology. The circuit is used to bias the CMUT by charging a buffer capacitor synchronously with the pulsing sequence, thus reducing the impact of the switching noise on the received echo signals. The small area of the circuit (about 1.5 cm 2 ) makes it possible to generate the bias voltage inside the probe, very close to the CMUT, making the proposed solution attractive for portable applications. Measurements and experiments are shown to demonstrate the effectiveness of the new approaches presented.

Nanofluidic bubble pump using surface tension directed gas injection

NARCIS (Netherlands)

Tas, Niels Roelof; Berenschot, Johan W.; Lammerink, Theodorus S.J.; Elwenspoek, Michael Curt; van den Berg, Albert

2002-01-01

A new concept for liquid manipulation has been developed and implemented in surface-micromachined fluid channels. It is based on the surface tension directed injection of a gas into the liquid flow through micrometer-sized holes in the microchannel wall. The injected gas is directed to an exhaust by

Dust, ice and gas in time (DIGIT): Herschel and Spitzer spectro-imaging of SMM3 and SMM4 in Serpens

Science.gov (United States)

Dionatos, O.; Jørgensen, J. K.; Green, J. D.; Herczeg, G. J.; Evans, N. J.; Kristensen, L. E.; Lindberg, J. E.; van Dishoeck, E. F.

2013-10-01

Context. Mid- and far-infrared observations of the environment around embedded protostars reveal a plethora of high excitation molecular and atomic emission lines. Different mechanisms for the origin of these lines have been proposed, including shocks induced by protostellar jets and radiation or heating by the embedded protostar of its immediate surroundings. Aims: By studying of the most important molecular and atomic coolants, we aim at constraining the physical conditions around the embedded protostars SMM3 and SMM4 in the Serpens molecular cloud core and measuring the CO/H2 ratio in warm gas. Methods: Spectro-imaging observations from the Spitzer Infrared Spectrograph (IRS) and the Herschel Photodetector Array Camera and Spectrometer (PACS) provide an almost complete wavelength coverage between 5 and 200 μm. Within this range, emission from all major molecular (H2, CO, H2O and OH) and many atomic ([OI], [CII], [FeII], [SiII] and [SI]) coolants of excited gas are detected. Emission line maps reveal the morphology of the observed emission and indicate associations between the different species. The excitation conditions for molecular species are assessed through rotational diagrams. Emission lines from major coolants are compared to the results of steady-state C- and J-type shock models. Results: Line emission tends to peak at distances of ~10-20″ from the protostellar sources with all but [CII] peaking at the positions of outflow shocks seen in near-IR and sub-millimeter interferometric observations. The [CII] emission pattern suggests that it is most likely excited from energetic UV radiation originating from the nearby flat-spectrum source SMM6. Excitation analysis indicates that H2 and CO originate in gas at two distinct rotational temperatures of ~300 K and 1000 K, while the excitation temperature for H2O and OH is ~100-200 K. The morphological and physical association between CO and H2 suggests a common excitation mechanism, which allows direct

FY 1994 Report on the technical results. Research and development of micromachine technologies (Development of highly functional maintenance technologies for power plants); 1994 nendo micromachine gijutsu no kenkyu kaihatsu seika hokokusho. Hatsuden shisetsuyo kokino maintenance gijutsu kaihatsu

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-09-01

This research and development project is aimed at development of the technologies for the micromachines provided with maintenance functions, e.g., for examination and maintenance of abnormal conditions in heat exchangers, piping systems or the like. The initial target is set at establishment of basic technologies for the micromachines, in consideration of the available technologies. The R and D activities are directed to (1) microcapsules for, e.g., micro power generators, (2) mother machines having controlling and instructing functions, (3) non-cabled examination modules, (4) cabled examination modules, and (5) total systems. The item (1) involves the micro power generators, and mechanisms of signal transmission, flaw finding and driving/suspension; the item (2) mechanisms of micro-optics and connection, group controlling, microbatteries, action type controlling, and artificial muscles; the item (3) expansion/contraction type transfer mechanisms, light energy supply, micro visual sensation, function connection, and concerted controlling; the item (4) tubular manipulators, and mechanisms of light-aided power generation and voltage elevation; and the item (5) maintenance and micromachine systems. (NEDO)

Motor, visual and emotional deficits in mice after closed-head mild traumatic brain injury are alleviated by the novel CB2 inverse agonist SMM-189.

Science.gov (United States)

Reiner, Anton; Heldt, Scott A; Presley, Chaela S; Guley, Natalie H; Elberger, Andrea J; Deng, Yunping; D'Surney, Lauren; Rogers, Joshua T; Ferrell, Jessica; Bu, Wei; Del Mar, Nobel; Honig, Marcia G; Gurley, Steven N; Moore, Bob M

2014-12-31

We have developed a focal blast model of closed-head mild traumatic brain injury (TBI) in mice. As true for individuals that have experienced mild TBI, mice subjected to 50-60 psi blast show motor, visual and emotional deficits, diffuse axonal injury and microglial activation, but no overt neuron loss. Because microglial activation can worsen brain damage after a concussive event and because microglia can be modulated by their cannabinoid type 2 receptors (CB2), we evaluated the effectiveness of the novel CB2 receptor inverse agonist SMM-189 in altering microglial activation and mitigating deficits after mild TBI. In vitro analysis indicated that SMM-189 converted human microglia from the pro-inflammatory M1 phenotype to the pro-healing M2 phenotype. Studies in mice showed that daily administration of SMM-189 for two weeks beginning shortly after blast greatly reduced the motor, visual, and emotional deficits otherwise evident after 50-60 psi blasts, and prevented brain injury that may contribute to these deficits. Our results suggest that treatment with the CB2 inverse agonist SMM-189 after a mild TBI event can reduce its adverse consequences by beneficially modulating microglial activation. These findings recommend further evaluation of CB2 inverse agonists as a novel therapeutic approach for treating mild TBI.

Physical and chemical characteristics of L1689-SMM16, an oscillating prestellar core in Ophiuchus

International Nuclear Information System (INIS)

Chitsazzadeh, S.; Di Francesco, J.; Sadavoy, S. I.; Schnee, S.; Friesen, R. K.; Shimajiri, Y.; Langston, G. I.; Bourke, T. L.; Keto, E. R.; Pineda, J. E.; Takakuwa, S.; Tatematsu, K.

2014-01-01

We present single-dish observations of the L1689-SMM16 core in the Ophiuchus molecular cloud in NH 3 (1, 1) and (2, 2) emission using the Green Bank Telescope, in N 2 H + (1-0) emission using the Nobeyama Radio Observatory, and in NH 2 D (1 1,1 a (--)1 0,1 s ), HCN (1-0), HNC (1-0), H 13 CO + (1-0), and HCO + (1-0) emission using the Mopra telescope. The morphologies of the integrated NH 3 (1, 1) and N 2 H + (1-0) emission well match that of 250 μm continuum emission. Line widths of NH 3 (1, 1) and N 2 H + (1-0) show the presence of transonic turbulence across the core. Jeans and virial analyses made using updated measurements of core mass and size confirm that L1689-SMM16 is prestellar, i.e., gravitationally bound. It also has accumulated more mass compared to its corresponding Jeans mass in the absence of magnetic fields and therefore is a 'super-Jeans' core. The high levels of X(NH 3 )/X(N 2 H + ) and deuterium fractionation reinforce the idea that the core has not yet formed a protostar. Comparing the physical parameters of the core with those of a Bonnor-Ebert sphere reveals the advanced evolutionary stage of L1689-SMM16 and shows that it might be unstable to collapse. We do not detect any evidence of infall motions toward the core. Instead, red asymmetry in the line profiles of HCN (1-0) and HNC (1-0) indicates the expansion of the outer layers of the core at a speed of ∼0.2 km s –1 to 0.3 km s –1 . For a gravitationally bound core, expansion in the outer layers might indicate that the core is experiencing oscillations.

Table of solar activity associated with coronal mass ejections observed by the SMM coronagraph/polarimeter in 1980. Technical note

International Nuclear Information System (INIS)

Webb, D.F.

1987-10-01

This report is the description and presentation of a table of solar activity considered to be associated with coronal mass ejections (CMEs) as observed during 1980 with the High Altitude Observatory's Coronagraph/Polarimeter (C/P) on the SMM spacecraft. The list has formed the basic data set for several studies, most prominently a study of CME associations published by Webb and Hundhausen (1987). An attendant source of CME data is the unpublished C/P Event List for 1980, which co-evolved with the association list under the guidance of Art Hundhausen. Discussions of the details of the selection and verification of the list of SMM CMEs are contained in the above paper as well as in this papers of Hundhausen et al. (1984) and Hundhausen (1987)

The laser micro-machining system for diamond anvil cell experiments and general precision machining applications at the High Pressure Collaborative Access Team.

Science.gov (United States)

Hrubiak, Rostislav; Sinogeikin, Stanislav; Rod, Eric; Shen, Guoyin

2015-07-01

We have designed and constructed a new system for micro-machining parts and sample assemblies used for diamond anvil cells and general user operations at the High Pressure Collaborative Access Team, sector 16 of the Advanced Photon Source. The new micro-machining system uses a pulsed laser of 400 ps pulse duration, ablating various materials without thermal melting, thus leaving a clean edge. With optics designed for a tight focus, the system can machine holes any size larger than 3 μm in diameter. Unlike a standard electrical discharge machining drill, the new laser system allows micro-machining of non-conductive materials such as: amorphous boron and silicon carbide gaskets, diamond, oxides, and other materials including organic materials such as polyimide films (i.e., Kapton). An important feature of the new system is the use of gas-tight or gas-flow environmental chambers which allow the laser micro-machining to be done in a controlled (e.g., inert gas) atmosphere to prevent oxidation and other chemical reactions in air sensitive materials. The gas-tight workpiece enclosure is also useful for machining materials with known health risks (e.g., beryllium). Specialized control software with a graphical interface enables micro-machining of custom 2D and 3D shapes. The laser-machining system was designed in a Class 1 laser enclosure, i.e., it includes laser safety interlocks and computer controls and allows for routine operation. Though initially designed mainly for machining of the diamond anvil cell gaskets, the laser-machining system has since found many other micro-machining applications, several of which are presented here.

The laser micro-machining system for diamond anvil cell experiments and general precision machining applications at the High Pressure Collaborative Access Team

International Nuclear Information System (INIS)

Hrubiak, Rostislav; Sinogeikin, Stanislav; Rod, Eric; Shen, Guoyin

2015-01-01

We have designed and constructed a new system for micro-machining parts and sample assemblies used for diamond anvil cells and general user operations at the High Pressure Collaborative Access Team, sector 16 of the Advanced Photon Source. The new micro-machining system uses a pulsed laser of 400 ps pulse duration, ablating various materials without thermal melting, thus leaving a clean edge. With optics designed for a tight focus, the system can machine holes any size larger than 3 μm in diameter. Unlike a standard electrical discharge machining drill, the new laser system allows micro-machining of non-conductive materials such as: amorphous boron and silicon carbide gaskets, diamond, oxides, and other materials including organic materials such as polyimide films (i.e., Kapton). An important feature of the new system is the use of gas-tight or gas-flow environmental chambers which allow the laser micro-machining to be done in a controlled (e.g., inert gas) atmosphere to prevent oxidation and other chemical reactions in air sensitive materials. The gas-tight workpiece enclosure is also useful for machining materials with known health risks (e.g., beryllium). Specialized control software with a graphical interface enables micro-machining of custom 2D and 3D shapes. The laser-machining system was designed in a Class 1 laser enclosure, i.e., it includes laser safety interlocks and computer controls and allows for routine operation. Though initially designed mainly for machining of the diamond anvil cell gaskets, the laser-machining system has since found many other micro-machining applications, several of which are presented here

A Micromachined Capacitive Pressure Sensor Using a Cavity-Less Structure with Bulk-Metal/Elastomer Layers and Its Wireless Telemetry Application

Directory of Open Access Journals (Sweden)

Yogesh B. Gianchandani

2008-04-01

Full Text Available This paper reports a micromachined capacitive pressure sensor intended for applications that require mechanical robustness. The device is constructed with two micromachined metal plates and an intermediate polymer layer that is soft enough to deform in a target pressure range. The plates are formed of micromachined stainless steel fabricated by batch-compatible micro-electro-discharge machining. A polyurethane roomtemperature- vulcanizing liquid rubber of 38-μm thickness is used as the deformable material. This structure eliminates both the vacuum cavity and the associated lead transfer challenges common to micromachined capacitive pressure sensors. For frequency-based interrogation of the capacitance, passive inductor-capacitor tanks are fabricated by combining the capacitive sensor with an inductive coil. The coil has 40 turns of a 127-μmdiameter copper wire. Wireless sensing is demonstrated in liquid by monitoring the variation in the resonant frequency of the tank via an external coil that is magnetically coupled with the tank. The sensitivity at room temperature is measured to be 23-33 ppm/KPa over a dynamic range of 340 KPa, which is shown to match a theoretical estimation. Temperature dependence of the tank is experimentally evaluated.

Hybrid micromachining using a nanosecond pulsed laser and micro EDM

International Nuclear Information System (INIS)

Kim, Sanha; Chung, Do Kwan; Shin, Hong Shik; Chu, Chong Nam; Kim, Bo Hyun

2010-01-01

Micro electrical discharge machining (micro EDM) is a well-known precise machining process that achieves micro structures of excellent quality for any conductive material. However, the slow machining speed and high tool wear are main drawbacks of this process. Though the use of deionized water instead of kerosene as a dielectric fluid can reduce the tool wear and increase the machine speed, the material removal rate (MRR) is still low. In contrast, laser ablation using a nanosecond pulsed laser is a fast and non-wear machining process but achieves micro figures of rather low quality. Therefore, the integration of these two processes can overcome the respective disadvantages. This paper reports a hybrid process of a nanosecond pulsed laser and micro EDM for micromachining. A novel hybrid micromachining system that combines the two discrete machining processes is introduced. Then, the feasibility and characteristics of the hybrid machining process are investigated compared to conventional EDM and laser ablation. It is verified experimentally that the machining time can be effectively reduced in both EDM drilling and milling by rapid laser pre-machining prior to micro EDM. Finally, some examples of complicated 3D micro structures fabricated by the hybrid process are shown

Achievement report on commissioned research of R and D in fiscal 1999 on micro-machine technologies. R and D of micro-machine technologies; 1999 nendo kenkyu seika hokokusho. Maikuro mashin gijutsu no kenkyu kaihatsu

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-03-01

With an objective to perform diagnoses and medical treatment in space limited portions in living organisms, research on micro-machine systems, research on a scanning type photographing unit in the medical micro-machine, and comprehensive surveys and researches have been conducted. This paper summarizes the achievements in fiscal 1999. In the research of a micro laser catheter, a prototype laser head having an outer diameter of 1 mm was fabricated, whereas composition was realized with a micro catheter having an outer diameter of 1.5 mm. With regard to the micro pressure sensor for catheterization, good active curving action was realized by a catheter in which a pressure sensor is mounted in the SMA curved catheter head. Research on the scanning type photographing unit has been carried out, for reducing further the diameter and size of an endoscope, on a photographing unit using laser beam whose cross section area of the tip optical section is about half of the conventional units. As a result, a high resolution scanning type photographing unit was realized based on the fiber optic system using a scanning mirror. In the comprehensive surveys and researches, items of information were collected in relation with the basic technologies for micro-machines. (NEDO)

Erosion resistant anti-ice surfaces generated by ultra short laser pulses

NARCIS (Netherlands)

Del Cerro, D.A.; Römer, G.R.B.E.; Huis in't Veld, A.J.

2010-01-01

Wetting properties of a wide range of materials can be modified by accurate laser micromachining with ultra short laser pulses. Controlling the surface topography in a micro and sub-micrometer scale allows the generation of water-repellent surfaces, which remain dry and prevent ice accumulation

Sustainable Materials Management (SMM) Web Academy Webinar: Building Collection Infrastructure for Composting: Success in the Greater Worcester, Massachusetts Area

Science.gov (United States)

This is a webinar page for the Sustainable Management of Materials (SMM) Web Academy webinar titled Let’s WRAP (Wrap Recycling Action Program): Best Practices to Boost Plastic Film Recycling in Your Community

Motor, Visual and Emotional Deficits in Mice after Closed-Head Mild Traumatic Brain Injury Are Alleviated by the Novel CB2 Inverse Agonist SMM-189

Directory of Open Access Journals (Sweden)

Anton Reiner

2014-12-01

Full Text Available We have developed a focal blast model of closed-head mild traumatic brain injury (TBI in mice. As true for individuals that have experienced mild TBI, mice subjected to 50–60 psi blast show motor, visual and emotional deficits, diffuse axonal injury and microglial activation, but no overt neuron loss. Because microglial activation can worsen brain damage after a concussive event and because microglia can be modulated by their cannabinoid type 2 receptors (CB2, we evaluated the effectiveness of the novel CB2 receptor inverse agonist SMM-189 in altering microglial activation and mitigating deficits after mild TBI. In vitro analysis indicated that SMM-189 converted human microglia from the pro-inflammatory M1 phenotype to the pro-healing M2 phenotype. Studies in mice showed that daily administration of SMM-189 for two weeks beginning shortly after blast greatly reduced the motor, visual, and emotional deficits otherwise evident after 50–60 psi blasts, and prevented brain injury that may contribute to these deficits. Our results suggest that treatment with the CB2 inverse agonist SMM-189 after a mild TBI event can reduce its adverse consequences by beneficially modulating microglial activation. These findings recommend further evaluation of CB2 inverse agonists as a novel therapeutic approach for treating mild TBI.

Characteristics of bursts observed by the SMM Gamma-Ray Spectrometer

Science.gov (United States)

Share, G. H.; Messina, D. C.; Iadicicco, A.; Matz, S. M.; Rieger, E.; Forrest, D. J.

1992-01-01

The Gamma Ray Spectrometer (GRS) on the SMM completed close to 10 years of highly successful operation when the spacecraft reentered the atmosphere on December 2, 1989. During this period the GRS detected 177 events above 300 keV which have been classified as cosmic gamma-ray bursts. A catalog of these events is in preparation which will include time profiles and spectra for all events. Visual inspection of the spectra indicates that emission typically extends into the MeV range, without any evidence for a high-energy cutoff; 17 of these events are also observed above 10 MeV. We find no convincing evidence for line-like emission features in any of the time-integrated spectra.

Instrumental and atmospheric background lines observed by the SMM gamma-ray spectrometer

Science.gov (United States)

Share, G. H.; Kinzer, R. L.; Strickman, M. S.; Letaw, J. R.; Chupp, E. L.

1989-01-01

Preliminary identifications of instrumental and atmospheric background lines detected by the gamma-ray spectrometer on NASA's Solar Maximum Mission satellite (SMM) are presented. The long-term and stable operation of this experiment has provided data of high quality for use in this analysis. Methods are described for identifying radioactive isotopes which use their different decay times. Temporal evolution of the features are revealed by spectral comparisons, subtractions, and fits. An understanding of these temporal variations has enabled the data to be used for detecting celestial gamma-ray sources.

Management of monoclonal gammopathy of undetermined significance (MGUS) and smoldering multiple myeloma (SMM).

Science.gov (United States)

Kyle, Robert A; Rajkumar, S Vincent

2011-06-01

Monoclonal gammopathy of undetermined significance (MGUS) is defined as a serum M protein level of less than 3 g/dL, less than 10% clonal plasma cells in the bone marrow, and the absence of end-organ damage. The prevalence of MGUS is 3.2% in the white population but is approximately twice that high in the black population. MGUS may progress to multiple myeloma, AL amyloidosis, Waldenström macroglobulinemia, or lymphoma. The risk of progression is approximately 1% per year, but the risk continues even after more than 25 years of observation. Risk factors for progression include the size of the serum M protein, the type of serum M protein, the number of plasma cells in the bone marrow, and the serum free light chain ratio. Smoldering (asymptomatic) multiple myeloma (SMM) is characterized by the presence of an M protein level of 3 g/dL or higher and/or 10% or more monoclonal plasma cells in the bone marrow but no evidence of end-organ damage. The overall risk of progression to a malignant condition is 10% per year for the first 5 years, approximately 3% per year for the next 5 years, and 1% to 2% per year for the following 10 years. Patients with both MGUS and SMM must be followed up for their lifetime.

New Effective Material Couple--Oxide Ceramic and Carbon Nanotube-- Developed for Aerospace Microsystem and Micromachine Technologies

Science.gov (United States)

Miyoshi, Kazuhisa; VanderWal, Randall L.; Tomasek, Aaron J.; Sayir, Ali; Farmer, Serene C.

2004-01-01

The prime driving force for using microsystem and micromachine technologies in transport vehicles, such as spacecraft, aircraft, and automobiles, is to reduce the weight, power consumption, and volume of components and systems to lower costs and increase affordability and reliability. However, a number of specific issues need to be addressed with respect to using microsystems and micromachines in aerospace applications--such as the lack of understanding of material characteristics; methods for producing and testing the materials in small batches; the limited proven durability and lifetime of current microcomponents, packaging, and interconnections; a cultural change with respect to system designs; and the use of embedded software, which will require new product assurance guidelines. In regards to material characteristics, there are significant adhesion, friction, and wear issues in using microdevices. Because these issues are directly related to surface phenomena, they cannot be scaled down linearly and they become increasingly important as the devices become smaller. When microsystems have contacting surfaces in relative motion, the adhesion and friction affect performance, energy consumption, wear damage, maintenance, lifetime and catastrophic failure, and reliability. Ceramics, for the most part, do not have inherently good friction and wear properties. For example, coefficients of friction in excess of 0.7 have been reported for ceramics and ceramic composite materials. Under Alternate Fuels Foundation Technologies funding, two-phase oxide ceramics developed for superior high-temperature wear resistance in NASA's High Operating Temperature Propulsion Components (HOTPC) project and new two-layered carbon nanotube (CNT) coatings (CNT topcoat/iron bondcoat/quartz substrate) developed in NASA's Revolutionary Aeropropulsion Concepts (RAC) project have been chosen as a materials couple for aerospace applications, including micromachines, in the nanotechnology

Fibroblast adhesion and activation onto micro-machined titanium surfaces.

Science.gov (United States)

Guillem-Marti, J; Delgado, L; Godoy-Gallardo, M; Pegueroles, M; Herrero, M; Gil, F J

2013-07-01

Surface modifications performed at the neck of dental implants, in the manner of micro-grooved surfaces, can reduce fibrous tissue encapsulation and prevent bacterial colonization, thereby improving fibrointegration and the formation of a biological seal. However, the applied procedures are technically complex and/or time consuming methods. The aim of this study was to analyse the fibroblast behaviour on modified titanium surfaces obtained, applying a simple and low-cost method. An array of titanium surfaces was obtained using a commercial computerized numerical control lathe, modifying the feed rate and the cutting depth. To elucidate the potential ability of the generated surfaces to activate connective tissue cells, a thorough gene (by real time - qPCR) and protein (by western blot or zymography) expression and cellular response characterization (cell morphology, cell adhesion and cell activation by secreting extracellular matrix (ECM) components and their enzyme regulators) was performed. Micro-grooved surfaces have statistically significant differences in the groove's width (approximately 10, 50 and 100 μm) depending on the applied advancing fixed speed. Field emission scanning electron microscopy images showed that fibroblasts oriented along the generated grooves, but they were only entirely accommodated on the wider grooves (≥50 μm). Micro-grooved surfaces exhibited an earlier cell attachment and activation, as seen by collagen Iα1 and fibronectin deposition and activation of ECM remodelling enzymes, compared with the other surfaces. However, fibroblasts could remain in an activated state on narrower surfaces (fibrotic response. © 2012 John Wiley & Sons A/S.

Micromachined microphone array on a chip for turbulent boundary layer measurements

Science.gov (United States)

Krause, Joshua Steven

A surface micromachined microphone array on a single chip has been successfully designed, fabricated, characterized, and tested for aeroacoustic purposes. The microphone was designed to have venting through the diaphragm, 64 elements (8x8) on the chip, and used a capacitive transduction scheme. The microphone was fabricated using the MEMSCAP PolyMUMPs process (a foundry polysilicon surface micromachining process) along with facilities at Tufts Micro and Nano Fabrication Facility (TMNF) where a Parylene-C passivation layer deposition and release of the microstructures were performed. The devices are packaged with low profile interconnects, presenting a maximum of 100 mum of surface topology. The design of an individual microphone was completed through the use of a lumped element model (LEM) to determine the theoretical performance of the microphone. Off-chip electronics were created to allow the microphone array outputs to be redirected to one of two channels, allowing dynamic reconfiguration of the effective transducer shape in software and provide 80 dB off isolation. The characterization was completed through the use of laser Doppler vibrometry (LDV), acoustic plane wave tube and free-field calibration, and electrical noise floor testing in a Faraday cage. Measured microphone sensitivity is 0.15 mV/Pa for an individual microphone and 8.7 mV/Pa for the entire array, in close agreement with model predictions. The microphones and electronics operate over the 200--40 000 Hz band. The dynamic range extends from 60 dB SPL in a 1 Hz band to greater than 150 dB SPL. Element variability was +/-0.05 mV/Pa in sensitivity with an array yield of 95%. Wind tunnel testing at flow rates of up to 205.8 m/s indicates that the devices continue to operate in flow without damage, and can be successfully reconfigured on the fly. Care has been taken to systematically remove contaminating signals (acoustic, vibration, and noise floor) from the wind tunnel data to determine actual

Results of a search for a new class of GRBS in the SMM data

Science.gov (United States)

Kouveliotou, C.; Cline, T. L.; Desai, U. D.; Dennis, B. R.; Orwig, L. E.

1986-01-01

The results of a search for the soft and short Gamma-Ray Bursts (GRBs) in the data of the Hard X-Ray Burst Spectrometer (HXRBS) on the Solar Maximum Mission (SMM) are presented. Data for four events are presented, including their time profiles and spectral characteristics. In one case the instrument time resolution reveals a total burst duration of 55 ms with rise and decay times of less than about 5 ms.

Physical and chemical characteristics of L1689-SMM16, an oscillating prestellar core in Ophiuchus

Energy Technology Data Exchange (ETDEWEB)

Chitsazzadeh, S.; Di Francesco, J.; Sadavoy, S. I. [Department of Physics and Astronomy, The University of Victoria, Victoria, BC V8P 5C2 (Canada); Schnee, S. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Friesen, R. K. [The Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St. George St., Toronto, ON M5S 3H4 (Canada); Shimajiri, Y. [Laboratoire AIM, CEA/DSM-CNRS-Université Paris Diderot, IRFU/Service d' Astrophysique, CEA Saclay, F-91191 Gif-sur-Yvette (France); Langston, G. I. [National Radio Astronomy Observatory, P.O. Box 2, Green Bank, WV 24944 (United States); Bourke, T. L.; Keto, E. R. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Pineda, J. E. [Institute for Astronomy, ETH Zurich, Wolfgang-Pauli-Strasse 27, CH-8093 Zurich (Switzerland); Takakuwa, S. [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China); Tatematsu, K., E-mail: schitsaz@uvic.ca [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)

2014-08-01

We present single-dish observations of the L1689-SMM16 core in the Ophiuchus molecular cloud in NH{sub 3} (1, 1) and (2, 2) emission using the Green Bank Telescope, in N{sub 2}H{sup +} (1-0) emission using the Nobeyama Radio Observatory, and in NH{sub 2}D (1{sub 1,1}{sup a}(--)1{sub 0,1}{sup s}), HCN (1-0), HNC (1-0), H{sup 13}CO{sup +} (1-0), and HCO{sup +} (1-0) emission using the Mopra telescope. The morphologies of the integrated NH{sub 3} (1, 1) and N{sub 2}H{sup +} (1-0) emission well match that of 250 μm continuum emission. Line widths of NH{sub 3} (1, 1) and N{sub 2}H{sup +} (1-0) show the presence of transonic turbulence across the core. Jeans and virial analyses made using updated measurements of core mass and size confirm that L1689-SMM16 is prestellar, i.e., gravitationally bound. It also has accumulated more mass compared to its corresponding Jeans mass in the absence of magnetic fields and therefore is a 'super-Jeans' core. The high levels of X(NH{sub 3})/X(N{sub 2}H{sup +}) and deuterium fractionation reinforce the idea that the core has not yet formed a protostar. Comparing the physical parameters of the core with those of a Bonnor-Ebert sphere reveals the advanced evolutionary stage of L1689-SMM16 and shows that it might be unstable to collapse. We do not detect any evidence of infall motions toward the core. Instead, red asymmetry in the line profiles of HCN (1-0) and HNC (1-0) indicates the expansion of the outer layers of the core at a speed of ∼0.2 km s{sup –1} to 0.3 km s{sup –1}. For a gravitationally bound core, expansion in the outer layers might indicate that the core is experiencing oscillations.

Micromachined integrated quantum circuit containing a superconducting qubit

Science.gov (United States)

Brecht, Teresa; Chu, Yiwen; Axline, Christopher; Pfaff, Wolfgang; Blumoff, Jacob; Chou, Kevin; Krayzman, Lev; Frunzio, Luigi; Schoelkopf, Robert

We demonstrate a functional multilayer microwave integrated quantum circuit (MMIQC). This novel hardware architecture combines the high coherence and isolation of three-dimensional structures with the advantages of integrated circuits made with lithographic techniques. We present fabrication and measurement of a two-cavity/one-qubit prototype, including a transmon coupled to a three-dimensional microwave cavity micromachined in a silicon wafer. It comprises a simple MMIQC with competitive lifetimes and the ability to perform circuit QED operations in the strong dispersive regime. Furthermore, the design and fabrication techniques that we have developed are extensible to more complex quantum information processing devices.

Design challenges for stepper motor actuated microvalve based on fine and micro-machining

NARCIS (Netherlands)

Fazal, I.; Elwenspoek, Michael Curt

2007-01-01

We present a normally open stepper motor actuated microvalve based on micro and fine-machining technique. In this paper, first we have described how the larger controllable flow range can be achieved with simple micromachining techniques and secondly we have presented the results which show how the

A LabVIEWTM-based scanning and control system for proton beam micromachining

International Nuclear Information System (INIS)

Bettiol, Andrew A.; Kan, J.A. van; Sum, T.C.; Watt, F.

2001-01-01

LabVIEW TM is steadily gaining in popularity as the programming language of choice for scientific data acquisition and control. This is due to the vast array of measurement instruments and data acquisition cards supported by the LabVIEW TM environment, and the relative ease with which advanced software can be programmed. Furthermore, virtual instruments that are designed for a given system can be easily ported to other LabVIEW TM platforms and hardware. This paper describes the new LabVIEW TM based scanning and control system developed specifically for proton beam micromachining (PBM) applications. The new system is capable of scanning figures at 16-bit resolution with improved sub-microsecond scan rates. Support for electrostatic beam blanking and external dose normalization using a TTL signal have been implemented. The new software incorporates a semi-automated dose calibration system, and a number of novel dose normalization methods. Limitations of the current beam scanning hardware are discussed in light of new results obtained from micromachining experiments performed in SU-8 photoresist

Demonstration of superconducting micromachined cavities

Energy Technology Data Exchange (ETDEWEB)

Brecht, T., E-mail: teresa.brecht@yale.edu; Reagor, M.; Chu, Y.; Pfaff, W.; Wang, C.; Frunzio, L.; Devoret, M. H.; Schoelkopf, R. J. [Department of Applied Physics, Yale University, New Haven, Connecticut 06511 (United States)

2015-11-09

Superconducting enclosures will be key components of scalable quantum computing devices based on circuit quantum electrodynamics. Within a densely integrated device, they can protect qubits from noise and serve as quantum memory units. Whether constructed by machining bulk pieces of metal or microfabricating wafers, 3D enclosures are typically assembled from two or more parts. The resulting seams potentially dissipate crossing currents and limit performance. In this letter, we present measured quality factors of superconducting cavity resonators of several materials, dimensions, and seam locations. We observe that superconducting indium can be a low-loss RF conductor and form low-loss seams. Leveraging this, we create a superconducting micromachined resonator with indium that has a quality factor of two million, despite a greatly reduced mode volume. Inter-layer coupling to this type of resonator is achieved by an aperture located under a planar transmission line. The described techniques demonstrate a proof-of-principle for multilayer microwave integrated quantum circuits for scalable quantum computing.

V/V(max) test applied to SMM gamma-ray bursts

Science.gov (United States)

Matz, S. M.; Higdon, J. C.; Share, G. H.; Messina, D. C.; Iadicicco, A.

1992-01-01

We have applied the V/V(max) test to candidate gamma-ray bursts detected by the Gamma-Ray Spectrometer (GRS) aboard the SMM satellite to examine quantitatively the uniformity of the burst source population. For a sample of 132 candidate bursts identified in the GRS data by an automated search using a single uniform trigger criterion we find average V/V(max) = 0.40 +/- 0.025. This value is significantly different from 0.5, the average for a uniform distribution in space of the parent population of burst sources; however, the shape of the observed distribution of V/V(max) is unusual and our result conflicts with previous measurements. For these reasons we can currently draw no firm conclusion about the distribution of burst sources.

Search for soft gamma repeaters in the SMM/HXRBS data

Science.gov (United States)

Kouveliotou, C.; Norris, J. P.; Wood, K. S.; Cline, T. L.; Dennis, B. R.; Desal, U. D.; Orwig, L. E.

1992-01-01

The triggered fast memory of the hard X-ray burst spectrometer (HXRBS) on board the SMM is used to describe the results of a search for short transients resembling soft gamma repeater (SGR) bursts. Memory data for a total of about 4000 burst triggers, out of which only a very few could be considered as valid SGR candidate events, are analyzed. The search methodology is outlined, the HXRBS exposure and sensitivity to SGR bursts are calculated, and the criteria which constrain the number of candidate events are described. An upper limit is given for the SGR source number density. This limit, combined with results from other relevant observations and the assumption of a neutron star origin, are applied to obtain a constraint on SGR-active lifetimes.

Evidence for explosive chromospheric evaporation in a solar flare observed with SMM

Science.gov (United States)

Zarro, D. M.; Saba, J. L. R.; Strong, K. T.; Canfield, R. C.; Metcalf, T.

1986-01-01

SMM soft X-ray data and Sacramento Peak Observatory H-alpha observations are combined in a study of the impulsive phase of a solar flare. A blue asymmetry, indicative of upflow motions, was observed in the coronal Ca XIX line during the soft X-ray rise phase. H-alpha redshifts, indicative of downward motions, were observed simultaneously in bright flare kernels during the period of hard X-ray emission. It is shown that, to within observational errors, the impulsive phase momentum transported by the upflowing soft X-ray plasma is equivalent to that of the downward moving chromospheric material.

Project: Micromachined High-Frequency Circuits For Sub-mm-wave Sensors

Science.gov (United States)

Papapolymerou, Ioannis John

2004-01-01

A novel micromachined resonator at 45 GHz based on a defect in a periodic electromagnetic bandgap structure (EBG) and a two-pole Tchebysbev filter with 1.4% 0.15 dB equiripple bandwidth and 2.3 dB loss employing this resonator are presented in this letter. The periodic bandgap structure is realized on a 400 micron thick high-resistivity silicon wafer using deep reactive ion etching techniques. The resonator and filter can be accessed via coplanar waveguide feeds.

High-power ultrashort fiber laser for solar cells micromachining

Science.gov (United States)

Lecourt, J.-B.; Duterte, C.; Liegeois, F.; Lekime, D.; Hernandez, Y.; Giannone, D.

2012-02-01

We report on a high-power ultra-short fiber laser for thin film solar cells micromachining. The laser is based on Chirped Pulse Amplification (CPA) scheme. The pulses are stretched to hundreds of picoseconds prior to amplification and can be compressed down to picosecond at high energy. The repetition rate is adjustable from 100 kHz to 1 MHz and the optical average output power is close to 13 W (before compression). The whole setup is fully fibred, except the compressor achieved with bulk gratings, resulting on a compact and reliable solution for cold ablation.

Numerical modelling of micro-machining of f.c.c. single crystal: Influence of strain gradients

KAUST Repository

Demiral, Murat; Roy, Anish; El Sayed, Tamer S.; Silberschmidt, Vadim V.

2014-01-01

of orthogonal micro-machining of f.c.c. single crystal copper was developed. The model was implemented in a commercial software ABAQUS/Explicit employing a user-defined subroutine VUMAT. Strain-gradient crystal-plasticity and conventional crystal

SMM-chemokines: a class of unnatural synthetic molecules as chemical probes of chemokine receptor biology and leads for therapeutic development.

Science.gov (United States)

Kumar, Santosh; Choi, Won-Tak; Dong, Chang-Zhi; Madani, Navid; Tian, Shaomin; Liu, Dongxiang; Wang, Youli; Pesavento, James; Wang, Jun; Fan, Xuejun; Yuan, Jian; Fritzsche, Wayne R; An, Jing; Sodroski, Joseph G; Richman, Douglas D; Huang, Ziwei

2006-01-01

Chemokines and their receptors play important roles in numerous physiological and pathological processes. To develop natural chemokines into receptor probes and inhibitors of pathological processes, the lack of chemokine-receptor selectivity must be overcome. Here, we apply chemical synthesis and the concept of modular modifications to generate unnatural synthetically and modularly modified (SMM)-chemokines that have high receptor selectivity and affinity, and reduced toxicity. A proof of the concept was shown by transforming the nonselective viral macrophage inflammatory protein-II into new analogs with enhanced selectivity and potency for CXCR4 or CCR5, two principal coreceptors for human immunodeficiency virus (HIV)-1 entry. These new analogs provided insights into receptor binding and signaling mechanisms and acted as potent HIV-1 inhibitors. These results support the concept of SMM-chemokines for studying and controlling the function of other chemokine receptors.

The first example of erbium triple-stranded helicates displaying SMM behaviour.

Science.gov (United States)

Gorczyński, Adam; Kubicki, Maciej; Pinkowicz, Dawid; Pełka, Robert; Patroniak, Violetta; Podgajny, Robert

2015-10-14

A series of isostructural C3-symmetrical triple stranded dinuclear lanthanide [Ln2L3](NO3)3 molecules have been synthesized using subcomponent self-assembly of Ln(NO3)3 with 2-(methylhydrazino)benzimidazole and 4-tert-butyl-2,6-diformylphenol, where Ln = Tb (1), Dy (2), Ho (3), Er (4), Tm (5), and Yb (6). The temperature dependent and field dependent magnetic properties of 1-6 were modeled using the van Vleck approximation including the crystal field term HCF, the super-exchange term HSE and the Zeeman term HZE. Ferromagnetic interactions were found in 1, 2, 4 and 6, while antiferromagnetic interactions were found in 3 and 5. The erbium analogue reveals field induced SMM behaviour.

Sustainable Materials Management (SMM) Web Academy Webinar: Compost from Food Waste: Understanding Soil Chemistry and Soil Biology on a College/University Campus

Science.gov (United States)

This page contains information about the Sustainable Materials Management (SMM) Web Academy Webinar Series titled Compost from Food Waste:Understanding Soil Chemistry and Soil Biology on a College/University Campus

Determination of solar flare accelerated ion angular distributions from SMM gamma ray and neutron measurements and determination of the He-3/H ratio in the solar photosphere from SMM gamma ray measurements. Final technical report, 1 July 1987-31 August 1989

International Nuclear Information System (INIS)

Lingenfelter, R.E.

1989-08-01

Comparisons of Solar Maximum Mission (SMM) observations of gamma-ray line and neutron emission with theoretical calculation of their expected production by flare accelerated ion interactions in the solar atmosphere have led to significant advances in the understanding of solar flare particle acceleration and interaction, as well as the flare process itself. These comparisons have enabled the determination of, not only the total number and energy spectrum of accelerated ions trapped at the sun, but also the ion angular distribution as they interact in the solar atmosphere. The Monte Carlo program was modified to include in the calculations of ion trajectories the effects of both mirroring in converging magnetic fields and of pitch angle scattering. Comparing the results of these calculations with the SMM observations, not only the angular distribution of the interacting ions can be determined, but also the initial angular distribution of the ions at acceleration. The reliable determination of the solar photospheric He-3 abundance is of great importance for understanding nucleosynthesis in the early universe and its implications for cosmology, as well as for the study of the evolution of the sun. It is also essential for the determinations of the spectrum and total number of flare accelerated ions from the SMM/GRS gamma-ray line measurements. Systematic Monte Carlo calculations of the time dependence were made as a function of the He-3 abundance and other variables. A new series of calculations were compared for the time-dependent flux of 2.223 MeV neutron capture line emission and the ratio of the time-integrated flux in the 2.223 MeV line to that in the 4.1 to 6.4 MeV nuclear deexcitation band

Etching characteristics of Si{110} in 20 wt% KOH with addition of hydroxylamine for the fabrication of bulk micromachined MEMS

Science.gov (United States)

Rao, A. V. Narasimha; Swarnalatha, V.; Pal, P.

2017-12-01

Anisotropic wet etching is a most widely employed for the fabrication of MEMS/NEMS structures using silicon bulk micromachining. The use of Si{110} in MEMS is inevitable when a microstructure with vertical sidewall is to be fabricated using wet anisotropic etching. In most commonly employed etchants (i.e. TMAH and KOH), potassium hydroxide (KOH) exhibits higher etch rate and provides improved anisotropy between Si{111} and Si{110} planes. In the manufacturing company, high etch rate is demanded to increase the productivity that eventually reduces the cost of end product. In order to modify the etching characteristics of KOH for the micromachining of Si{110}, we have investigated the effect of hydroxylamine (NH2OH) in 20 wt% KOH solution. The concentration of NH2OH is varied from 0 to 20% and the etching is carried out at 75 °C. The etching characteristics which are studied in this work includes the etch rates of Si{110} and silicon dioxide, etched surface morphology, and undercutting at convex corners. The etch rate of Si{110} in 20 wt% KOH + 15% NH2OH solution is measured to be four times more than that of pure 20 wt% KOH. Moreover, the addition of NH2OH increases the undercutting at convex corners and enhances the etch selectivity between Si and SiO2.

A Novel Piezo-Actuator-Sensor Micromachine for Mechanical Characterization of Micro-Specimens

Directory of Open Access Journals (Sweden)

Leila Ladani

2010-12-01

Full Text Available Difficulties associated with testing and characterization of materials at microscale demands for new technologies and devices that are capable of measuring forces and strains at microscale. To address this issue, a novel electroactive-based micro-electro-mechanical machine is designed. The micromachine is comprised of two electroactive (piezoelectric micro-elements mounted on a rigid frame. Electrical activation of one of the elements causes it to expand and induce a stress in the intervening micro-specimen. The response of the microspecimen to the stress is measured by the deformation and thereby voltage/resistance induced in the second electro-active element. The concept is theoretically proven using analytical modeling in conjunction with non-linear, three dimensional finite element analyses for the micromachine. Correlation of the output voltage to the specimen stiffness is shown. It is also demonstrated through finite element and analytical analysis that this technique is capable of detecting non-linear behavior of materials. A characteristic curve for an isotropic specimen exhibiting linear elastic behavior is developed. Application of the proposed device in measuring coefficient of thermal expansion is explored and analytical analysis is conducted.

Micromachining. CERN Courier, Jul-Aug 1995, v. 35(5)

International Nuclear Information System (INIS)

Wilson, Martin

1995-01-01

Full text: As well as making microcircuit components, X-ray lithography can also be used to make very small mechanical parts, either by using directly the exposed and developed photoresist, or as a mould to produce the component in another material such as ceramic or metal. In this revolutionary technology, metal components are made via the LIGA (Lithographic Galvanoformung und Abformung) technique in which the exposed and developed photoresist is coated with a conducting material and then electroplated, after which the resist is stripped away. In addition to fine size and precision resolution, X-rays offer the advantage of deep penetration and small scattering through the resist, so that patterns may be up to a millimetre deep, with very accurate straightness in directions parallel to the beam. Micromachining via LIGA was developed at KfK Karlsruhe; commercialization and further development is being vigorously pursued by the Institut fur Mikrotechnik in Mainz and by Microparts GmbH in Karlsruhe. Significant developments have been made at the Synchrotron Radiation Centre in Madison, Wisconsin, with new programmes start-ing at SRRC (Taiwan), CAMD (Baton Rouge, Louisiana), and LURE (Paris). There is now an active European Special Interest Group for LIGA. Commercially manufactured micromachines are starting to be used in sensors and connectors. The ability to integrate microdevices with microelectronics raises many interesting possibilities for the future, notably in medicine and for intelligent sensors. In all cases, however, widespread adoption will be governed by the ability to mass-produce cheaply, requiring high volume production. The high intensities of synchrotron radiation will assist in achieving these large throughputs

Synthesis and structure of large single crystalline silver hexagonal microplates suitable for micromachining

Energy Technology Data Exchange (ETDEWEB)

Lyutov, Dimitar L.; Genkov, Kaloyan V.; Zyapkov, Anton D.; Tsutsumanova, Gichka G.; Tzonev, Atanas N. [Department of Solid State Physics and Microelectronics, Faculty of Physics, University of Sofia, 5, J. Bouchier Blvd, Sofia (Bulgaria); Lyutov, Lyudmil G. [Department of General and Inorganic Chemistry, Faculty of Chemistry, University of Sofia, 1, J. Bouchier Blvd, Sofia (Bulgaria); Russev, Stoyan C., E-mail: scr@phys.uni-sofia.bg [Department of Solid State Physics and Microelectronics, Faculty of Physics, University of Sofia, 5, J. Bouchier Blvd, Sofia (Bulgaria)

2014-01-15

We report a simple one-step synthesis method of large single crystalline Ag (111) hexagonal microplates with sharp edges and a size of up to tens of microns. Single silver crystals were produced by reduction silver nitrate aqueous solution with 4-(methylamino)phenol sulfate. Scanning and transmission electron microscopy, energy-dispersive X-ray spectroscopy, selected area electron diffraction and optical microscopy techniques were combined to characterize the crystals. It is shown that the microplates can be easily dispersed and transferred as single objects onto different substrates and subsequently used as a high quality plasmonic starting material for micromachining of future nanocomponents, using modern top-down techniques like focused-ion beam milling and gas injection deposition. - Highlights: • Synthesis of large Ag hexagonal microplates with high crystallinity. • It is shown and discussed the role of twinning for the anisotropic 2D growth. • The Ag plates are stable in water and can be dispersed onto different substrates. • Their positioning and subsequent micromachining with FIB/GIS is demonstrated. • Suitable starting material for future plasmonic nanocomponents.

Silicon micromachining using a high-density plasma source

International Nuclear Information System (INIS)

McAuley, S.A.; Ashraf, H.; Atabo, L.; Chambers, A.; Hall, S.; Hopkins, J.; Nicholls, G.

2001-01-01

Dry etching of Si is critical in satisfying the demands of the micromachining industry. The micro-electro-mechanical systems (MEMS) community requires etches capable of high aspect ratios, vertical profiles, good feature size control and etch uniformity along with high throughput to satisfy production requirements. Surface technology systems' (STS's) high-density inductively coupled plasma (ICP) etch tool enables a wide range of applications to be realized whilst optimizing the above parameters. Components manufactured from Si using an STS ICP include accelerometers and gyroscopes for military, automotive and domestic applications. STS's advanced silicon etch (ASE TM ) has also allowed the first generation of MEMS-based optical switches and attenuators to reach the marketplace. In addition, a specialized application for fabricating the next generation photolithography exposure masks has been optimized for 200 mm diameter wafers, to depths of ∼750 μm. Where the profile is not critical, etch rates of greater than 8 μm min -1 have been realized to replace previous methods such as wet etching. This is also the case for printer applications. Specialized applications that require etching down to pyrex or oxide often result in the loss of feature size control at the interface; this is an industry wide problem. STS have developed a technique to address this. The rapid progression of the industry has led to development of the STS ICP etch tool, as well as the process. (author)

Sustainable Materials Management (SMM) Web Academy Webinar: How to Reduce Wasted Food: EPA’s Food Waste Reduction Tools for Food Services & Restaurants

Science.gov (United States)

This is a webinar page for the Sustainable Management of Materials (SMM) Web Academy webinar titled Let’s WRAP (Wrap Recycling Action Program): Best Practices to Boost Plastic Film Recycling in Your Community

Abnormalities in Dynamic Brain Activity Caused by Mild Traumatic Brain Injury Are Partially Rescued by the Cannabinoid Type-2 Receptor Inverse Agonist SMM-189.

Science.gov (United States)

Liu, Yu; McAfee, Samuel S; Guley, Natalie M; Del Mar, Nobel; Bu, Wei; Heldt, Scott A; Honig, Marcia G; Moore, Bob M; Reiner, Anton; Heck, Detlef H

2017-01-01

Mild traumatic brain injury (mTBI) can cause severe long-term cognitive and emotional deficits, including impaired memory, depression, and persevering fear, but the neuropathological basis of these deficits is uncertain. As medial prefrontal cortex (mPFC) and hippocampus play important roles in memory and emotion, we used multi-site, multi-electrode recordings of oscillatory neuronal activity in local field potentials (LFPs) in awake, head-fixed mice to determine if the functioning of these regions was abnormal after mTBI, using a closed-skull focal cranial blast model. We evaluated mPFC, hippocampus CA1, and primary somatosensory/visual cortical areas (S1/V1). Although mTBI did not alter the power of oscillations, it did cause increased coherence of θ (4-10 Hz) and β (10-30 Hz) oscillations within mPFC and S1/V1, reduced CA1 sharp-wave ripple (SWR)-evoked LFP activity in mPFC, downshifted SWR frequencies in CA1, and enhanced θ-γ phase-amplitude coupling (PAC) within mPFC. These abnormalities might be linked to the impaired memory, depression, and persevering fear seen after mTBI. Treatment with the cannabinoid type-2 (CB2) receptor inverse agonist SMM-189 has been shown to mitigate functional deficits and neuronal injury after mTBI in mice. We found that SMM-189 also reversed most of the observed neurophysiological abnormalities. This neurophysiological rescue is likely to stem from the previously reported reduction in neuron loss and/or the preservation of neuronal function and connectivity resulting from SMM-189 treatment, which appears to stem from the biasing of microglia from the proinflammatory M1 state to the prohealing M2 state by SMM-189.

Frontside-micromachined planar piezoresistive vibration sensor: Evaluating performance in the low frequency test range

Directory of Open Access Journals (Sweden)

Lan Zhang

2014-01-01

Full Text Available Using a surface piezoresistor diffusion method and front-side only micromachining process, a planar piezoresistive vibration sensor was successfully developed with a simple structure, lower processing cost and fewer packaging difficulties. The vibration sensor had a large sector proof mass attached to a narrow flexure. Optimization of the boron diffusion piezoresistor placed on the edge of the narrow flexure greatly improved the sensitivity. Planar vibration sensors were fabricated and measured in order to analyze the effects of the sensor dimensions on performance, including the values of flexure width and the included angle of the sector. Sensitivities of fabricated planar sensors of 0.09–0.46 mV/V/g were measured up to a test frequency of 60 Hz. The sensor functioned at low voltages (<3 V and currents (<1 mA with a high sensitivity and low drift. At low background noise levels, the sensor had performance comparable to a commercial device.

Frontside-micromachined planar piezoresistive vibration sensor: Evaluating performance in the low frequency test range

Energy Technology Data Exchange (ETDEWEB)

Zhang, Lan; Lu, Jian, E-mail: jian-lu@aist.go.jp; Takagi, Hideki; Maeda, Ryutaro [Research Center for Ubiquitous MEMS and Micro Engineering (UMEMSME), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8564 (Japan)

2014-01-15

Using a surface piezoresistor diffusion method and front-side only micromachining process, a planar piezoresistive vibration sensor was successfully developed with a simple structure, lower processing cost and fewer packaging difficulties. The vibration sensor had a large sector proof mass attached to a narrow flexure. Optimization of the boron diffusion piezoresistor placed on the edge of the narrow flexure greatly improved the sensitivity. Planar vibration sensors were fabricated and measured in order to analyze the effects of the sensor dimensions on performance, including the values of flexure width and the included angle of the sector. Sensitivities of fabricated planar sensors of 0.09–0.46 mV/V/g were measured up to a test frequency of 60 Hz. The sensor functioned at low voltages (<3 V) and currents (<1 mA) with a high sensitivity and low drift. At low background noise levels, the sensor had performance comparable to a commercial device.

FY1995 development of micromachine technology based on insects; 1995 nendo konchu wo kihan to suru micromachine gijutsu no kakuritsu to jitsuyoka

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

If we develop micromachines by reducing simply the size of conventional mechanical systems, we cannot get sufficient performances of them because of scale-effect. Small natural creatures, insects, have very good structures and functions reasonable for their small size. In this research, basic characteristics of sensors, actuators, information processing functions, etc. of insects are studied and artificial systems similar to them are developed for industrial application. (1) Compound eyes: Insect compound eyes is the visual sensor which is composed of microlenses which are distributed three-dimensionally, receptors which vibrate with small amplitude around an optical axis and neural networks. In this research, the large scale model (several centimeters sized) of insect compound eyes has been developed. (2) Pheromone sensor: Pheromone gas sensor has been made of real male silkworm moth antenae. This sensor has been proved to work well as the female pheromone detector. This sensor was installed at the nose part of a wheeled mobile robot and this robot was observed to act like a real silkworm moth subjected to female pheromone stream. (3) Electrostatic microactuator: Generally speaking, high voltage(higher than 100V) electric power is necessary to actuate the electrostatic actuator. It was considered to be impossible to actuate them directly from CMOS. In this research, a new electrostatic actuator which can be actuated with less than 10V voltage can cause a fairly large displacement. (4) Hydraulic actuator: For micromachines, hydraulic pressure will be applicable for actuation. Structures may be simple and scale effect may give an advantageous characteristics for microsize. A butterfly-type flying robot was developed and it flied up along a vertical bar. (NEDO)

Search for gamma-ray transients using the SMM spectrometer

Science.gov (United States)

Share, G. H.; Harris, M. J.; Leising, M. D.; Messina, D. C.

1993-01-01

Observations for transient radiation made by the Gamma Ray Spectrometer on the SMM satellite are summarized. Spectra were obtained from 215 solar flares and 177 gamma-ray bursts. No narrow or moderately broadened lines were observed in any of the bursts. The rate of bursts is consistent with a constant over the mission but is weakly correlated with solar activity. No evidence was found for bursts of 511 keV line emission, unaccompanied by a strong continuum, at levels not less than 0.05 gamma/sq cm s for bursts lasting not more than 16 s. No evidence was found for broad features near 1 MeV from Cyg X-1, the Galactic center, or the Crab in 12-d integrations at levels not less than 0.006 gamma/sq cm s. No evidence was found for transient celestial narrow-line emission from 300 keV to 7 MeV on min-to-hrs-long time scales from 1984 to 1989.

Origin of SMM behaviour in an asymmetric Er(III) Schiff base complex: a combined experimental and theoretical study.

Science.gov (United States)

Das, Chinmoy; Upadhyay, Apoorva; Vaidya, Shefali; Singh, Saurabh Kumar; Rajaraman, Gopalan; Shanmugam, Maheswaran

2015-04-11

An asymmetric erbium(III) Schiff base complex [Er(HL)2(NO3)3] was synthesized which shows SMM behaviour with an Ueff of 5.2 K. Dipolar interaction in 1 significantly reduced upon dilution which increases the barrier height to 51.5 K. Ab initio calculations were performed to shed light on the mechanism of magnetization relaxation.

CO2-laser micromachining and back-end processing for rapid production of PMMA-based microfluidic systems

DEFF Research Database (Denmark)

Klank, Henning; Kutter, Jörg Peter; Geschke, Oliver

2002-01-01

, a three-layer polymer microstructure with included optical fibers was fabricated within two days. The use of CO2-laser systems to produce microfluidic systems has not been published before. These systems provide a cost effective alternative to UV-laser systems and they are especially useful......In this article, we focus on the enormous potential of a CO2-laser system for rapidly producing polymer microfluidic structures. The dependence was assessed of the depth and width of laser-cut channels on the laser beam power and on the number of passes of the beam along the same channel...... for microstructured PMMA [poly( methyl methacrylate)] parts were investigated, such as solvent-assisted glueing, melting, laminating and surface activation using a plasma asher. A solvent-assisted thermal bonding method proved to be the most time-efficient one. Using laser micromachining together with bonding...

Effect of Ligand Field Tuning on the SMM Behavior for Three Related Alkoxide-Bridged Dysprosium Dimers.

Science.gov (United States)

Peng, Yan; Mereacre, Valeriu; Baniodeh, Amer; Lan, Yanhua; Schlageter, Martin; Kostakis, George E; Powell, Annie K

2016-01-04

The synthesis and characterization of three Dy2 compounds, [Dy2(HL1)2(NO3)4] (1), [Dy2(L2)2(NO3)4] (2), and [Dy2(HL3)2(NO3)4] (3), formed using related tripodal ligands with a central tertiary amine bearing picolyl and alkoxy arms, 2-[(2-hydroxy-ethyl)-pyridin-2-ylmethylamino]-ethanol (H2L1), 2-(bis-pyridin-2-ylmethylamino)-ethanol (HL2), and 2-(bis-pyridin-2-ylmethylamino)-propane-1,3-diol (H2L3), are reported. The compounds are rare examples of alkoxide-bridged {Dy2} complexes and display capped square antiprism coordination geometry around each Dy(III) ion. Changes in the ligand field environment around the Dy(III) ions brought about through variations in the ligand donors can be gauged from the magnetic properties, with compounds 1 and 2 showing antiparallel coupling between the Dy(III) ions and 3 showing parallel coupling. Furthermore, slow relaxation of the magnetization typical of SMM behavior could be observed for compounds 2 and 3, suggesting that small variations in the ligand field can have a significant influence on the slow relaxation processes responsible for SMM behavior of Dy(III)-based systems.

Nickel silicide thin films as masking and structural layers for silicon bulk micro-machining by potassium hydroxide wet etching

International Nuclear Information System (INIS)

Bhaskaran, M; Sriram, S; Sim, L W

2008-01-01

This paper studies the feasibility of using titanium and nickel silicide thin films as mask materials for silicon bulk micro-machining. Thin films of nickel silicide were found to be more resistant to wet etching in potassium hydroxide. The use of nickel silicide as a structural material, by fabricating micro-beams of varying dimensions, is demonstrated. The micro-structures were realized using these thin films with wet etching using potassium hydroxide solution on (1 0 0) and (1 1 0) silicon substrates. These results show that nickel silicide is a suitable alternative to silicon nitride for silicon bulk micro-machining

Evidence for solar flare directivity from the Gamma-Ray Spectrometer aboard the SMM satellite

Science.gov (United States)

Vestrand, W. T.; Forrest, D. J.; Chupp, E. L.; Rieger, E.; Share, G. H.

1986-01-01

A number of observations from the SMM Gamma-Ray Spectrometer are presented that altogether strongly indicate that the high-energy emission from flares is anisotropic. They are: (1) the fraction of events detected at energies above 300 keV near the limb is significantly higher than is expected for isotropically emitting flares; (2) there is a statistically significant center-to-limb variation in the 300-1000-keV spectra of flares; and (3) nearly all of the events detected at above 10 MeV are located near the limb.

Instanton calculus without equations of motion: semiclassics from monodromies of a Riemann surface

Science.gov (United States)

Gulden, Tobias; Janas, Michael; Kamenev, Alex

2015-02-01

Instanton calculations in semiclassical quantum mechanics rely on integration along trajectories which solve classical equations of motion. However in systems with higher dimensionality or complexified phase space these are rarely attainable. A prime example are spin-coherent states which are used e.g. to describe single molecule magnets (SMM). We use this example to develop instanton calculus which does not rely on explicit solutions of the classical equations of motion. Energy conservation restricts the complex phase space to a Riemann surface of complex dimension one, allowing to deform integration paths according to Cauchy’s integral theorem. As a result, the semiclassical actions can be evaluated without knowing actual classical paths. Furthermore we show that in many cases such actions may be solely derived from monodromy properties of the corresponding Riemann surface and residue values at its singular points. As an example, we consider quenching of tunneling processes in SMM by an applied magnetic field.

Lifetime predictions for the Solar Maximum Mission (SMM) and San Marco spacecraft

Science.gov (United States)

Smith, E. A.; Ward, D. T.; Schmitt, M. W.; Phenneger, M. C.; Vaughn, F. J.; Lupisella, M. L.

1989-01-01

Lifetime prediction techniques developed by the Goddard Space Flight Center (GSFC) Flight Dynamics Division (FDD) are described. These techniques were developed to predict the Solar Maximum Mission (SMM) spacecraft orbit, which is decaying due to atmospheric drag, with reentry predicted to occur before the end of 1989. Lifetime predictions were also performed for the Long Duration Exposure Facility (LDEF), which was deployed on the 1984 SMM repair mission and is scheduled for retrieval on another Space Transportation System (STS) mission later this year. Concepts used in the lifetime predictions were tested on the San Marco spacecraft, which reentered the Earth's atmosphere on December 6, 1988. Ephemerides predicting the orbit evolution of the San Marco spacecraft until reentry were generated over the final 90 days of the mission when the altitude was less than 380 kilometers. The errors in the predicted ephemerides are due to errors in the prediction of atmospheric density variations over the lifetime of the satellite. To model the time dependence of the atmospheric densities, predictions of the solar flux at the 10.7-centimeter wavelength were used in conjunction with Harris-Priester (HP) atmospheric density tables. Orbital state vectors, together with the spacecraft mass and area, are used as input to the Goddard Trajectory Determination System (GTDS). Propagations proceed in monthly segments, with the nominal atmospheric drag model scaled for each month according to the predicted monthly average value of F10.7. Calibration propagations are performed over a period of known orbital decay to obtain the effective ballistic coefficient. Progagations using plus or minus 2 sigma solar flux predictions are also generated to estimate the despersion in expected reentry dates. Definitive orbits are compared with these predictions as time expases. As updated vectors are received, these are also propagated to reentryto continually update the lifetime predictions.

Sustainable Materials Management (SMM) Electronics Challenge Data

Science.gov (United States)

On September 22, 2012, EPA launched the SMM Electronics Challenge. The Challenge encourages electronics manufacturers, brand owners and retailers to strive to send 100 percent of the used electronics they collect from the public, businesses and within their own organizations to third-party certified electronics refurbishers and recyclers. The Challenge??s goals are to: 1). Ensure responsible recycling through the use of third-party certified recyclers, 2). Increase transparency and accountability through public posting of electronics collection and recycling data, and 3). Encourage outstanding performance through awards and recognition. By striving to send 100 percent of used electronics collected to certified recyclers and refurbishers, Challenge participants are ensuring that the used electronics they collect will be responsibly managed by recyclers that maximize reuse and recycling, minimize exposure to human health and the environment, ensure the safe management of materials by downstream handlers, and require destruction of all data on used electronics. Electronics Challenge participants are publicly recognized on EPA's website as a registrant, new participant, or active participant. Awards are offered in two categories - tier and champion. Tier awards are given in recognition of achieving all the requirements under a gold, silver or bronze tier. Champion awards are given in two categories - product and non-product. For champion awards, a product is an it

Immunogenicity and persistence of the 13-valent Pneumococcal Conjugate Vaccine (PCV13) in patients with untreated Smoldering Multiple Myeloma (SMM): A pilot study.

Science.gov (United States)

Bahuaud, Mathilde; Bodilis, Hélène; Malphettes, Marion; Maugard Landre, Anaïs; Matondo, Caroline; Bouscary, Didier; Batteux, Frédéric; Launay, Odile; Fermand, Jean-Paul

2017-11-01

Smoldering multiple myeloma (SMM) is an asymptomatic clonal plasma cell disorder that frequently progress to multiple myeloma (MM), a disease at high risk of pneumococcal infections. Moreover, if the polysaccharide vaccine is poorly immunogenic in MM, the 13-valent conjugated vaccine has never been tested in clonal plasma cell disorders. We evaluated its immunogenicity for 7 serotypes in 20 patients ≥ 50 years of age with smoldering multiple myeloma (SMM) pre and post routine-vaccination with PCV13. Concentrations of IgG specific for 7 serotypes were measured at baseline, 1, 6, and 12 months after vaccination by standardized ELISA and an Opsonophagocytic Assay (OPA). The primary endpoint was the proportion of patients responding to at least 5 of the 7 serotypes by ELISA at one month. At 1 month post vaccination, 12 patients (60%) were responders by ELISA, among whom 8 were also responders by OPA. At 6 months, 6 (30% of total) of the 12 responders had persistent immunity, and only 2 (10% of total) at 12 months. These results suggested a partial response in this population and a rapid decrease in antibody levels in the first months of vaccination. Although one injection of the 13-valent pneumococcal conjugate vaccine is immunogenic in some patients with SMM, the response is transient. Repeated injections are likely to be needed for effective and sustained protection.

Simulation of the Mitra 15 micro-machine on IBM 360/91. Microprogramming of the fast Fourier transform

International Nuclear Information System (INIS)

Augustides, Jean

1973-01-01

As computing time did not allow working in real time, and as different methods had been proposed to reduce the computing time (the Cooley-Tuckey method, the use of specific FFT processors), this thesis proposes an intermediate solution, between the entirely programmed solution and the entirely cabled solution. After some generalities on micro-programming (definition, history, benefits and drawbacks, perspectives), the author reports the micro-programming of the Mitra 15 micro-machine: description of the machine, memory, command memory and associated circuits, interruptions and suspensions, descriptions of micro-statements, execution of a micro-statement. Programs and subroutines developed for the modelling of Mitra 15 micro-machine on IBM 360/91 are presented. Then, the author reports the micro-programming of the fast Fourier transform: theory, program description, and test

Hypersonic force measurements using internal balance based on optical micromachined Fabry-Perot interferometry

Science.gov (United States)

Qiu, Huacheng; Min, Fu; Zhong, Shaolong; Song, Xin; Yang, Yanguang

2018-03-01

Force measurements using wind tunnel balance are necessary for determining a variety of aerodynamic performance parameters, while the harsh environment in hypersonic flows requires that the measurement instrument should be reliable and robust, in against strong electromagnetic interference, high vacuum, or metal (oxide) dusts. In this paper, we demonstrated a three-component internal balance for hypersonic aerodynamic force measurements, using novel optical micromachined Fabry-Perot interferometric (FPI) strain gauges as sensing elements. The FPI gauges were fabricated using Micro-Opto-Electro-Mechanical Systems (MOEMS) surface and bulk fabrication techniques. High-reflectivity coatings are used to form a high-finesse Fabry-Perot cavity, which benefits a high resolution. Antireflective and passivation coatings are used to reduce unwanted interferences. The FPI strain gauge based balance has been calibrated and evaluated in a Mach 5 hypersonic flow. The results are compared with the traditional technique using the foil resistive strain gauge balance, indicating that the proposed balance based on the MOEMS FPI strain gauge is reliable and robust and is potentially suitable for the hypersonic wind tunnel harsh environment.

The complete far-infrared and submillimeter spectrum of the Class 0 protostar Serpens SMM1 obtained with Herschel

DEFF Research Database (Denmark)

R. Goicoechea, Javier; Cernicharo, J.; Karska, A.

2012-01-01

We present the first complete 55-671 um spectral scan of a low-mass Class 0 protostar (Serpens SMM1) taken with the PACS and SPIRE spectrometers on board Herschel. More than 145 lines have been detected, most of them rotationally excited lines of 12CO (full ladder from J=4-3 to 42-41), H2O, OH, 13...

Capacitive micromachined ultrasonic transducer arrays as tunable acoustic metamaterials

Energy Technology Data Exchange (ETDEWEB)

Lani, Shane W., E-mail: shane.w.lani@gmail.com, E-mail: karim.sabra@me.gatech.edu, E-mail: levent.degertekin@me.gatech.edu; Sabra, Karim G. [George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 801Ferst Drive, Georgia 30332-0405 (United States); Wasequr Rashid, M.; Hasler, Jennifer [School of Electrical and Computer Engineering, Georgia Institute of Technology, Van Leer Electrical Engineering Building, 777 Atlantic Drive NW, Atlanta, Georgia 30332-0250 (United States); Levent Degertekin, F. [George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 801Ferst Drive, Georgia 30332-0405 (United States); School of Electrical and Computer Engineering, Georgia Institute of Technology, Van Leer Electrical Engineering Building, 777 Atlantic Drive NW, Atlanta, Georgia 30332-0250 (United States)

2014-02-03

Capacitive Micromachined Ultrasonic Transducers (CMUTs) operating in immersion support dispersive evanescent waves due to the subwavelength periodic structure of electrostatically actuated membranes in the array. Evanescent wave characteristics also depend on the membrane resonance which is modified by the externally applied bias voltage, offering a mechanism to tune the CMUT array as an acoustic metamaterial. The dispersion and tunability characteristics are examined using a computationally efficient, mutual radiation impedance based approach to model a finite-size array and realistic parameters of variation. The simulations are verified, and tunability is demonstrated by experiments on a linear CMUT array operating in 2-12 MHz range.

Micromachined high-performance RF passives in CMOS substrate

International Nuclear Information System (INIS)

Li, Xinxin; Ni, Zao; Gu, Lei; Wu, Zhengzheng; Yang, Chen

2016-01-01

This review systematically addresses the micromachining technologies used for the fabrication of high-performance radio-frequency (RF) passives that can be integrated into low-cost complementary metal-oxide semiconductor (CMOS)-grade (i.e. low-resistivity) silicon wafers. With the development of various kinds of post-CMOS-compatible microelectromechanical systems (MEMS) processes, 3D structural inductors/transformers, variable capacitors, tunable resonators and band-pass/low-pass filters can be compatibly integrated into active integrated circuits to form monolithic RF system-on-chips. By using MEMS processes, including substrate modifying/suspending and LIGA-like metal electroplating, both the highly lossy substrate effect and the resistive loss can be largely eliminated and depressed, thereby meeting the high-performance requirements of telecommunication applications. (topical review)

Characterization of bulk-micromachined direct-bonded silicon nanofilters

Science.gov (United States)

Tu, Jay K.; Huen, Tony; Szema, Robert; Ferrari, Mauro

1998-03-01

The ability to separate 30-100 nm particles - nanofiltration - is critical for many biomedical applications. Where this filtration needs to be absolute, such as for viral elimination in the blood fractionation process, the large variations in pore size found with conventional polymeric filters can lead to the unwanted presence of viruses in the filtrate. To overcome this problem, we have developed a filter with micromachined channels sandwiched between two bonded silicon wafers. These channels are formed through the selective deposition and then removal of a thermally-grown oxide, the thickness of which can be controlled to +/- 4 percent for 30 nm pores. In this paper, we will present both the gas and liquid characterization, and the filtration studies done on 44 and 100 nm beads.

Optimized design of micromachined electric field mills to maximize electrostatic field sensitivity

OpenAIRE

Zhou, Yu; Shafai, Cyrus

2016-01-01

This paper describes the design optimization of a micromachined electric field mill, in relation to maximizing its output signal. The cases studied are for a perforated electrically grounded shutter vibrating laterally over sensing electrodes. It is shown that when modeling the output signal of the sensor, the differential charge on the sense electrodes when exposed to vs. visibly shielded from the incident electric field must be considered. Parametric studies of device dimensions show that t...

Fabrication and characterization of a micromachined swirl-shaped ionic polymer metal composite actuator with electrodes exhibiting asymmetric resistance.

Science.gov (United States)

Feng, Guo-Hua; Liu, Kim-Min

2014-05-12

This paper presents a swirl-shaped microfeatured ionic polymer-metal composite (IPMC) actuator. A novel micromachining process was developed to fabricate an array of IPMC actuators on a glass substrate and to ensure that no shortcircuits occur between the electrodes of the actuator. We demonstrated a microfluidic scheme in which surface tension was used to construct swirl-shaped planar IPMC devices of microfeature size and investigated the flow velocity of Nafion solutions, which formed the backbone polymer of the actuator, within the microchannel. The unique fabrication process yielded top and bottom electrodes that exhibited asymmetric surface resistance. A tool for measuring surface resistance was developed and used to characterize the resistances of the electrodes for the fabricated IPMC device. The actuator, which featured asymmetric electrode resistance, caused a nonzero-bias current when the device was driven using a zero-bias square wave, and we propose a circuit model to describe this phenomenon. Moreover, we discovered and characterized a bending and rotating motion when the IPMC actuator was driven using a square wave. We observed a strain rate of 14.6% and a displacement of 700 μm in the direction perpendicular to the electrode surfaces during 4.5-V actuation.

3D Printed Microtransporters: Compound Micromachines for Spatiotemporally Controlled Delivery of Therapeutic Agents.

Science.gov (United States)

Huang, Tian-Yun; Sakar, Mahmut Selman; Mao, Angelo; Petruska, Andrew J; Qiu, Famin; Chen, Xue-Bo; Kennedy, Stephen; Mooney, David; Nelson, Bradley J

2015-11-01

Functional compound micromachines are fabricated by a design methodology using 3D direct laser writing and selective physical vapor deposition of magnetic materials. Microtransporters with a wirelessly controlled Archimedes screw pumping mechanism are engineered. Spatiotemporally controlled collection, transport, and delivery of micro particles, as well as magnetic nanohelices inside microfluidic channels are demonstrated. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sustainable Materials Management (SMM) Web Academy Webinar: Wasted Food to Energy: How 6 Water Resource Recovery Facilities are Boosting Biogas Production & the Bottom Line

Science.gov (United States)

This is a webinar page for the Sustainable Management of Materials (SMM) Web Academy webinar titled Let’s WRAP (Wrap Recycling Action Program): Best Practices to Boost Plastic Film Recycling in Your Community

Sustainable Materials Management (SMM) Web Academy Webinar: Cupertino CA and Cambridge MA: Tips for How Communities Can Successfully Engage Businesses to Divert Food Scraps

Science.gov (United States)

This is a webinar page for the Sustainable Management of Materials (SMM) Web Academy webinar titled Let’s WRAP (Wrap Recycling Action Program): Best Practices to Boost Plastic Film Recycling in Your Community

Sustainable Materials Management (SMM) Web Academy Webinar: An Introduction to Lithium Batteries and the Challenges that they Pose to the Waste and Recycling Industry

Science.gov (United States)

This is a webinar page for the Sustainable Management of Materials (SMM) Web Academy webinar titled, An Introduction to Lithium Batteries and the Challenges that they Pose to the Waste and Recycling Industry.

Immunogenicity and persistence of the 13-valent Pneumococcal Conjugate Vaccine (PCV13 in patients with untreated Smoldering Multiple Myeloma (SMM: A pilot study

Directory of Open Access Journals (Sweden)

Mathilde Bahuaud

2017-11-01

Full Text Available Smoldering multiple myeloma (SMM is an asymptomatic clonal plasma cell disorder that frequently progress to multiple myeloma (MM, a disease at high risk of pneumococcal infections. Moreover, if the polysaccharide vaccine is poorly immunogenic in MM, the 13-valent conjugated vaccine has never been tested in clonal plasma cell disorders. We evaluated its immunogenicity for 7 serotypes in 20 patients ≥ 50 years of age with smoldering multiple myeloma (SMM pre and post routine-vaccination with PCV13.Concentrations of IgG specific for 7 serotypes were measured at baseline, 1, 6, and 12 months after vaccination by standardized ELISA and an Opsonophagocytic Assay (OPA. The primary endpoint was the proportion of patients responding to at least 5 of the 7 serotypes by ELISA at one month.At 1 month post vaccination, 12 patients (60% were responders by ELISA, among whom 8 were also responders by OPA. At 6 months, 6 (30% of total of the 12 responders had persistent immunity, and only 2 (10% of total at 12 months. These results suggested a partial response in this population and a rapid decrease in antibody levels in the first months of vaccination.Although one injection of the 13-valent pneumococcal conjugate vaccine is immunogenic in some patients with SMM, the response is transient. Repeated injections are likely to be needed for effective and sustained protection. Keywords: Immunology, Vaccines, Infectious disease

High-intensity fibre laser design for micro-machining applications

Science.gov (United States)

Ortiz-Neria, D. I.; Martinez-Piñón, F.; Hernandez-Escamilla, H.; Alvarez-Chavez, J. A.

2010-11-01

This work is focused on the design of a 250W high-intensity continuous-wave fibre optic laser with a 15μm spot size beam and a beam parameter product (BPP) of 1.8 for its use on Laser-assisted Cold Spray process (LCS) in the micro-machining areas. The metal-powder deposition process LCS, is a novel method based on Cold Spray technique (CS) assisted by laser technology. The LCS accelerates metal powders by the use of a high-pressure gas in order to achieve flash welding of particles over substrate. In LCS, the critical velocity of impact is lower with respect with CS while the powder particle is heated before the deposition by a laser beam. Furthermore, LCS does not heat the powder to achieve high temperatures as it happens in plasma processes. This property puts aside cooling problems which normally happen in sintered processes with high oxygen/nitrogen concentration levels. LCS will be used not only in deposition of thin layers. After careful design, proof of concept, experimental data, and prototype development, it should be feasible to perform micro-machining precise work with the use of the highintensity fibre laser presented in this work, and selective deposition of particles, in a similar way to the well-known Direct Metal Laser Sintering process (DMLS). The fibre laser consists on a large-mode area, Yb3+-doped, semi-diffraction limited, 25-m fibre laser cavity, operating in continuous wave regime. The fibre shows an arguably high slope-efficiency with no signs of roll-over. The measured M2 value is 1.8 and doping concentration of 15000ppm. It was made with a slight modification of the traditional MCVD technique. A full optical characterization will be presented.

Observations of A0535 + 26 with the SMM satellite

Science.gov (United States)

Sembay, S.; Schwartz, R. A.; Orwig, L. E.; Dennis, B. R.; Davies, S. R.

1990-01-01

An examination of archival data from the hard X-ray instruments on the Solar Maximum Mission (SMM) satellite has revealed a previously undetected outburst from the recurrent X-ray transient, A0535 + 26. The outburst occurred in June 1983 and reached a peak intensity of about 2 crab units in the energy range 32-91 keV. The outburst was detected over a span of 18 days, and the pulse period was observed to spin-up with an average rate of about -6 x 10 to the -8th s/s. A recently proposed model for A0535 + 26 has a pulsar powered by a short-lived accretion disk. A thin accretion disk model is fitted to the present data, assuming an orbital period of 111 days. Two solutions to the magnetic moment of the neutron star are derived. The slow rotator solution is more consistent with the model than the fast rotator, on the grounds that the conditions for the formation of an accretion disk are more favorable for a lower magnetic field strength.

3D capacitive tactile sensor using DRIE micromachining

Science.gov (United States)

Chuang, Chiehtang; Chen, Rongshun

2005-07-01

This paper presents a three dimensional micro capacitive tactile sensor that can detect normal and shear forces which is fabricated using deep reactive ion etching (DRIE) bulk silicon micromachining. The tactile sensor consists of a force transmission plate, a symmetric suspension system, and comb electrodes. The sensing character is based on the changes of capacitance between coplanar sense electrodes. High sensitivity is achieved by using the high aspect ratio interdigital electrodes with narrow comb gaps and large overlap areas. The symmetric suspension mechanism of this sensor can easily solve the coupling problem of measurement and increase the stability of the structure. In this paper, the sensor structure is designed, the capacitance variation of the proposed device is theoretically analyzed, and the finite element analysis of mechanical behavior of the structures is performed.

An electro-magnetic micromachined actuator monolithically integrated with a vertical shutter for variable optical attenuation

International Nuclear Information System (INIS)

Hung, Shao Hsuan; Hsieh, Hsin-Ta; John Su, Guo-Dung

2008-01-01

The design, fabrication and test results of an electromagnetic-actuated micromachined variable optical attenuator (VOA) are reported in this paper. Optical attenuation is achieved by moving a shutter into the light path between a pair of single mode fiber collimators. The shutter, consisting of a 500 µm × 1200 µm vertical micromirror, is monolithically integrated with an actuation flap. The micromirror was made by tetra-methyl ammonium hydroxide (TMAH) anisotropic wet etching with a sharp edge and a smooth reflecting surface. By arranging fiber collimators in different configurations, the reported VOA can be used as either normally-on or normally-off modes due to its relatively large shutter surface. The insertion loss of the VOA is 0.2 dB and 0.4 dB for normally-on and normally-off modes, respectively. Both optical and mechanical simulation models of the device were discussed, and the theoretical calculations based on these models offered an efficient way to predict the performance of the shutter-type VOA. The controllable attenuation range is approximately 40 dB with a driving voltage less than 0.5 V, and the driving power is less than 2 mW. A response time of 5 ms is achieved by applying proper driving waveform

SMM hard X-ray observations of the soft gamma-ray repeater 1806-20

Science.gov (United States)

Kouveliotou, C.; Norris, J. P.; Cline, T. L.; Dennis, B. R.; Desai, U. D.; Orwig, L. E.

1987-01-01

Six bursts from the soft gamma-ray repeater (SGR) 1806-20 have been recorded with the SMM Hard X-ray Burst Spectrometer during a highly active phase in 1983. Rise and decay times of less than 5 ns have been detected. Time profiles of these events indicate low-level emission prior to and after the main peaks. The results suggest that SGRs are distinguished from classical gamma-ray bursts by repetition, softer nonvarying spectra, short durations, simple temporal profiles, and a tendency for source locations to correlate with Population I objects. SGR characteristics differ from those of type I X-ray bursts, but they appear to have similarities with the type II bursts from the Rapid Burster.

SMM hard X-ray observations of the soft gamma-ray repeater 1806-20

International Nuclear Information System (INIS)

Kouveliotou, C.; Norris, J.P.; Cline, T.L.; Dennis, B.R.; Desai, U.D.; Orwig, L.E.

1987-01-01

Six bursts from the soft gamma-ray repeater (SGR) 1806-20 have been recorded with the SMM Hard X-ray Burst Spectrometer during a highly active phase in 1983. Rise and decay times of less than 5 ns have been detected. Time profiles of these events indicate low-level emission prior to and after the main peaks. The results suggest that SGRs are distinguished from classical gamma-ray bursts by repetition, softer nonvarying spectra, short durations, simple temporal profiles, and a tendency for source locations to correlate with Population I objects. SGR characteristics differ from those of type I X-ray bursts, but they appear to have similarities with the type II bursts from the Rapid Burster. 19 references

Channeling-based collimators for generation of microbeams produced by silicon micromachining technology

International Nuclear Information System (INIS)

Guidi, V.; Antonini, A.; Milan, E.; Ronzoni, A.; Martinelli, G.; Biryukov, V.M.; Chesnokov, Yu.A.

2006-01-01

The growing interest on micro-beams in recent years and the combined development of channeling technology in high-energy physics have opened the way to new concepts for micro-beams devices. Silicon micromachining technology is here applied to manufacture micro-collimators in inexpensive and feasible ways. Both dry and wet etchings can be employed for the purpose, though the latter technique appears to be cheaper and easier. Two designs for micro-collimator devices have been considered and preliminary samples have been produced accordingly

Parallel-plate submicron gap formed by micromachined low-density pillars for near-field radiative heat transfer

International Nuclear Information System (INIS)

Ito, Kota; Miura, Atsushi; Iizuka, Hideo; Toshiyoshi, Hiroshi

2015-01-01

Near-field radiative heat transfer has been a subject of great interest due to the applicability to thermal management and energy conversion. In this letter, a submicron gap between a pair of diced fused quartz substrates is formed by using micromachined low-density pillars to obtain both the parallelism and small parasitic heat conduction. The gap uniformity is validated by the optical interferometry at four corners of the substrates. The heat flux across the gap is measured in a steady-state and is no greater than twice of theoretically predicted radiative heat flux, which indicates that the parasitic heat conduction is suppressed to the level of the radiative heat transfer or less. The heat conduction through the pillars is modeled, and it is found to be limited by the thermal contact resistance between the pillar top and the opposing substrate surface. The methodology to form and evaluate the gap promotes the near-field radiative heat transfer to various applications such as thermal rectification, thermal modulation, and thermophotovoltaics

Parallel-plate submicron gap formed by micromachined low-density pillars for near-field radiative heat transfer

Energy Technology Data Exchange (ETDEWEB)

Ito, Kota, E-mail: kotaito@mosk.tytlabs.co.jp [Toyota Central Research and Development Laboratories, Nagakute, Aichi 480-1192 (Japan); Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8904 (Japan); Miura, Atsushi; Iizuka, Hideo [Toyota Central Research and Development Laboratories, Nagakute, Aichi 480-1192 (Japan); Toshiyoshi, Hiroshi [Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, Komaba, Meguro-ku, Tokyo 153-8904 (Japan)

2015-02-23

Near-field radiative heat transfer has been a subject of great interest due to the applicability to thermal management and energy conversion. In this letter, a submicron gap between a pair of diced fused quartz substrates is formed by using micromachined low-density pillars to obtain both the parallelism and small parasitic heat conduction. The gap uniformity is validated by the optical interferometry at four corners of the substrates. The heat flux across the gap is measured in a steady-state and is no greater than twice of theoretically predicted radiative heat flux, which indicates that the parasitic heat conduction is suppressed to the level of the radiative heat transfer or less. The heat conduction through the pillars is modeled, and it is found to be limited by the thermal contact resistance between the pillar top and the opposing substrate surface. The methodology to form and evaluate the gap promotes the near-field radiative heat transfer to various applications such as thermal rectification, thermal modulation, and thermophotovoltaics.

Study of surfactant-added TMAH for applications in DRIE and wet etching-based micromachining

Science.gov (United States)

Tang, B.; Shikida, M.; Sato, K.; Pal, P.; Amakawa, H.; Hida, H.; Fukuzawa, K.

2010-06-01

In this paper, etching anisotropy is evaluated for a number of different crystallographic orientations of silicon in a 0.1 vol% Triton-X-100 added 25 wt% tetramethylammonium hydroxide (TMAH) solution using a silicon hemisphere. The research is primarily aimed at developing advanced applications of wet etching in microelectromechanical systems (MEMS). The etching process is carried out at different temperatures in the range of 61-81 °C. The etching results of silicon hemisphere and different shapes of three-dimensional structures in {1 0 0}- and {1 1 0}-Si surfaces are analyzed. Significantly important anisotropy, different from a traditional etchant (e.g. pure KOH and TMAH), is investigated to extend the applications of the wet etching process in silicon bulk micromachining. The similar etching behavior of exact and vicinal {1 1 0} and {1 1 1} planes in TMAH + Triton is utilized selectively to remove the scalloping from deep reactive-ion etching (DRIE) etched profiles. The direct application of the present research is demonstrated by fabricating a cylindrical lens with highly smooth etched surface finish. The smoothness of a micro-lens at different locations is measured qualitatively by a scanning electron microscope and quantitatively by an atomic force microscope. The present paper provides a simple and effective fabrication method of the silicon micro-lens for optical MEMS applications.

A Three-Dimensional Enormous Surface Area Aluminum Microneedle Array with Nanoporous Structure

OpenAIRE

Chen, Po Chun; Hsieh, Sheng Jen; Chen, Chien Chon; Zou, Jun

2013-01-01

We proposed fabricating an aluminum microneedle array with a nanochannel structure on the surface by combining micromachining, electrolyte polishing, and anodization methods. The microneedle array provides a three-dimensional (3D) structure that possesses several hundred times more surface area than a traditional nanochannel template. Therefore, the microneedle array can potentially be used in many technology applications. This 3D microneedle array device can not only be used for painless inj...

High efficiency on-chip Dielectric Resonator Antennna using micromachining technology

KAUST Repository

Sallam, Mai O.

2015-10-26

In this paper, a novel cylindrical Dielectric Resonator Antenna (DRA) operating at 60 GHz is introduced. The antenna is fabricated using a high-resistivity silicon wafer. The DR is defined in the wafer using micromachining technology. The feeding network is located at the other side of the wafer. The proposed antenna is simulated using HFSS and the results are verified by measurements. The antenna radiation is mainly along the broadside direction. The measured gain, radiation efficiency, and bandwidth are 7 dBi, 74.65%, and 2.23 GHz respectively. The antenna is characterized by high polarization purity where the maximum cross-polarization is -15 dB. © 2015 IEEE.

High efficiency on-chip Dielectric Resonator Antennna using micromachining technology

KAUST Repository

Sallam, Mai O.; Serry, Mohamed; Shamim, Atif; De Raedt, Walter; Sedky, Sherif; Vandenbosch, Guy A. E.; Soliman, Ezzeldin A.

2015-01-01

In this paper, a novel cylindrical Dielectric Resonator Antenna (DRA) operating at 60 GHz is introduced. The antenna is fabricated using a high-resistivity silicon wafer. The DR is defined in the wafer using micromachining technology. The feeding network is located at the other side of the wafer. The proposed antenna is simulated using HFSS and the results are verified by measurements. The antenna radiation is mainly along the broadside direction. The measured gain, radiation efficiency, and bandwidth are 7 dBi, 74.65%, and 2.23 GHz respectively. The antenna is characterized by high polarization purity where the maximum cross-polarization is -15 dB. © 2015 IEEE.

RF Performance of a 600-720 GHz Sideband Separating Mixer with All-Copper Micromachined Waveguide Mixer Block

NARCIS (Netherlands)

Mena, F. P.; Kooi, J.; Baryshev, A. M.; Lodewijk, C. F. J.; Klapwijk, T. M.; Wild, W.; Desmaris, V.; Meledin, D.; Pavolotsky, A.; Belitsky, V.; Wild, Wolfgang

2008-01-01

Here we report on the RF performance of a 2SB mixer (600-720 GHz) fabricated in a new method that combines traditional micromachining with waveguide components fabricated by photolithography and electroplating. The latter allows reaching, in a reproducible way, the stringent accuracies necessary for

Steric hindrances create a discrete linear Dy4 complex exhibiting SMM behaviour.

Science.gov (United States)

Lin, Shuang-Yan; Zhao, Lang; Ke, Hongshan; Guo, Yun-Nan; Tang, Jinkui; Guo, Yang; Dou, Jianmin

2012-03-21

Two linear tetranuclear lanthanide complexes of general formula [Ln(4)(L)(2)(C(6)H(5)COO)(12)(MeOH)(4)], where HL = 2,6-bis((furan-2-ylmethylimino)methyl)-4-methylphenol, () and Ln(III) = Dy(III) (1) and Gd(III) (2), have been synthesized and characterized. The crystal structural analysis demonstrates that two Schiff-base ligands inhibit the growth of benzoate bridged 1D chains, leading to the isolation of discrete tetranuclear complexes due to their steric hindrances. Every Ln(III) ion is coordinated by eight donor atoms in a distorted bicapped trigonal-prismatic arrangement. Alternating current (ac) susceptibility measurements of complex 1 reveal a frequency- and temperature-dependent out-of-phase signal under zero dc field, typical of single-molecule magnet (SMM) behaviour with an anisotropic barrier Δ(eff) = 17.2 K.

Structural design considerations for micromachined solid-oxide fuel cells

Science.gov (United States)

Srikar, V. T.; Turner, Kevin T.; Andrew Ie, Tze Yung; Spearing, S. Mark

Micromachined solid-oxide fuel cells (μSOFCs) are among a class of devices being investigated for portable power generation. Optimization of the performance and reliability of such devices requires robust, scale-dependent, design methodologies. In this first analysis, we consider the structural design of planar, electrolyte-supported, μSOFCs from the viewpoints of electrochemical performance, mechanical stability and reliability, and thermal behavior. The effect of electrolyte thickness on fuel cell performance is evaluated using a simple analytical model. Design diagrams that account explicitly for thermal and intrinsic residual stresses are presented to identify geometries that are resistant to fracture and buckling. Analysis of energy loss due to in-plane heat conduction highlights the importance of efficient thermal isolation in microscale fuel cell design.

A new family of Ln₇ clusters with an ideal D(3h) metal-centered trigonal prismatic geometry, and SMM and photoluminescence behaviors.

Science.gov (United States)

Mazarakioti, Eleni C; Poole, Katye M; Cunha-Silva, Luis; Christou, George; Stamatatos, Theocharis C

2014-08-14

The first use of the flexible Schiff base ligand N-salicylidene-2-aminocyclohexanol in metal cluster chemistry has afforded a new family of Ln7 clusters with ideal D(3h) point group symmetry and metal-centered trigonal prismatic topology; solid-state and solution studies revealed SMM and photoluminescence behaviors.

Sustainable Materials Management (SMM) Web Academy Webinar Series: A Step-by-Step Guide to Conducting a Wasted Food Assessment with the Reducing Wasted Food & Packaging Toolkit

Science.gov (United States)

This is a webinar page for the Sustainable Management of Materials (SMM) Web Academy webinar titled Let’s WRAP (Wrap Recycling Action Program): Best Practices to Boost Plastic Film Recycling in Your Community

Study of SMM flares in gamma-rays and neutrons

Science.gov (United States)

Dunphy, Philip P.; Chupp, Edward L.

1992-01-01

This report summarizes the results of the research supported by NASA grant NAGW-2755 and lists the papers and publications produced through the grant. The objective of the work was to study solar flares that produced observable signals from high-energy (greater than 10 MeV) gamma-rays and neutrons in the Solar Maximum Mission (SMM) Gamma-Ray Spectrometer (GRS). In 3 of 4 flares that had been studied previously, most of the neutrons and neutral pions appear to have been produced after the 'main' impulsive phase as determined from hard x-rays and gamma-rays. We, therefore, proposed to analyze the timing of the high-energy radiation, and its implications for the acceleration, trapping, and transport of flare particles. It was equally important to characterize the spectral shapes of the interacting energetic electrons and protons - another key factor in constraining possible particle acceleration mechanisms. In section 2.0, we discuss the goals of the research. In section 3.0, we summarize the results of the research. In section 4.0, we list the papers and publications produced under the grant. Preprints or reprints of the publications are attached as appendices.

Microfabrication in free-standing gallium nitride using UV laser micromachining

International Nuclear Information System (INIS)

Gu, E.; Howard, H.; Conneely, A.; O'Connor, G.M.; Illy, E.K.; Knowles, M.R.H.; Edwards, P.R.; Martin, R.W.; Watson, I.M.; Dawson, M.D.

2006-01-01

Gallium nitride (GaN) and related alloys are important semiconductor materials for fabricating novel photonic devices such as ultraviolet (UV) light-emitting diodes (LEDs) and vertical cavity surface-emitting lasers (VCSELs). Recent technical advances have made free-standing GaN substrates available and affordable. However, these materials are strongly resistant to wet chemical etching and also, low etch rates restrict the use of dry etching. Thus, to develop alternative high-resolution processing for these materials is increasingly important. In this paper, we report the fabrication of microstructures in free-standing GaN using pulsed UV lasers. An effective method was first developed to remove the re-deposited materials due to the laser machining. In order to achieve controllable machining and high resolution in GaN, machining parameters were carefully optimised. Under the optimised conditions, precision features such as holes (through holes, blind or tapered holes) on a tens of micrometer length scale have been machined. To fabricate micro-trenches in GaN with vertical sidewalls and a flat bottom, different process strategies of laser machining were tested and optimised. Using this technique, we have successfully fabricated high-quality micro-trenches in free-standing GaN with various widths and depths. The approach combining UV laser micromachining and other processes is also discussed. Our results demonstrate that the pulsed UV laser is a powerful tool for fabricating precision microstructures and devices in gallium nitride

Обзор методологии SMM в Синет

OpenAIRE

Лю Чжуняо; Кметь Елена Борисовна

2016-01-01

в статье уточнена значимость социальных медиа и содержание маргетинга в социальных сетях (SMM), сформулированы особенности и тенденции развития SMM в китайском Интернет (Синет) и его методология.

Millimeter length micromachining using a heavy ion nuclear microprobe with standard magnetic scanning

International Nuclear Information System (INIS)

Nesprías, F.; Debray, M.E.; Davidson, J.; Kreiner, A.J.

2013-01-01

In order to increase the scanning length of our microprobe, we have developed an irradiation procedure suitable for use in any nuclear microprobe, extending at least up to 400% the length of our heavy ion direct writing facility using standard magnetic exploration. Although this method is limited to patterns of a few millimeters in only one direction, it is useful for the manufacture of curved waveguides, optical devices such Mach–Zehnder modulators, directional couplers as well as channels for micro-fluidic applications. As an example, this technique was applied to the fabrication of 3 mm 3D-Mach–Zehnder modulators in lithium niobate with short Y input/output branches and long shaped parallel-capacitor control electrodes. To extend and improve the quality of the machined structures we developed new scanning control software in LabView™ platform. The new code supports an external dose normalization, electrostatic beam blanking and is capable of scanning figures at 16 bit resolution using a National Instruments™ PCI-6731 High-Speed I/O card. A deep and vertical micromachining process using swift 35 Cl ions 70 MeV bombarding energy and direct write patterning was performed on LiNbO 3 , a material which exhibits a strong natural anisotropy to conventional etching. The micromachined structures show the feasibility of this method for manufacturing micro-fluidic channels as well

Millimeter length micromachining using a heavy ion nuclear microprobe with standard magnetic scanning

Energy Technology Data Exchange (ETDEWEB)

Nesprías, F. [Gerencia de Investigación y Aplicaciones, Comisión Nacional de Energía Atómica, Av. Gral Paz 1499 (1650), San Martín, Buenos Aires (Argentina); Debray, M.E., E-mail: debray@tandar.cnea.gov.ar [Gerencia de Investigación y Aplicaciones, Comisión Nacional de Energía Atómica, Av. Gral Paz 1499 (1650), San Martín, Buenos Aires (Argentina); Escuela de Ciencia y Tecnología. Universidad Nacional de Gral. San Martín, M. De Irigoyen 3100 (1650), San Martín, Buenos Aires (Argentina); Davidson, J. [Gerencia de Investigación y Aplicaciones, Comisión Nacional de Energía Atómica, Av. Gral Paz 1499 (1650), San Martín, Buenos Aires (Argentina); CONICET, Avda. Rivadavia 1917 (C1033AAJ), Ciudad Autónoma de Buenos Aires (Argentina); Kreiner, A.J. [Gerencia de Investigación y Aplicaciones, Comisión Nacional de Energía Atómica, Av. Gral Paz 1499 (1650), San Martín, Buenos Aires (Argentina); Escuela de Ciencia y Tecnología. Universidad Nacional de Gral. San Martín, M. De Irigoyen 3100 (1650), San Martín, Buenos Aires (Argentina); CONICET, Avda. Rivadavia 1917 (C1033AAJ), Ciudad Autónoma de Buenos Aires (Argentina); and others

2013-04-01

In order to increase the scanning length of our microprobe, we have developed an irradiation procedure suitable for use in any nuclear microprobe, extending at least up to 400% the length of our heavy ion direct writing facility using standard magnetic exploration. Although this method is limited to patterns of a few millimeters in only one direction, it is useful for the manufacture of curved waveguides, optical devices such Mach–Zehnder modulators, directional couplers as well as channels for micro-fluidic applications. As an example, this technique was applied to the fabrication of 3 mm 3D-Mach–Zehnder modulators in lithium niobate with short Y input/output branches and long shaped parallel-capacitor control electrodes. To extend and improve the quality of the machined structures we developed new scanning control software in LabView™ platform. The new code supports an external dose normalization, electrostatic beam blanking and is capable of scanning figures at 16 bit resolution using a National Instruments™ PCI-6731 High-Speed I/O card. A deep and vertical micromachining process using swift {sup 35}Cl ions 70 MeV bombarding energy and direct write patterning was performed on LiNbO{sub 3}, a material which exhibits a strong natural anisotropy to conventional etching. The micromachined structures show the feasibility of this method for manufacturing micro-fluidic channels as well.

Micromachined On-Chip Dielectric Resonator Antenna Operating at 60 GHz

KAUST Repository

Sallam, Mai

2015-06-01

This paper presents a novel cylindrical Dielectric Resonator Antenna (DRA) suitable for millimeter-wave on-chip systems. The antenna was fabricated from a single high resistivity silicon wafer via micromachining technology. The new antenna was characterized using HFSS and experimentally with good agreement been found between the simulations and experiment. The proposed DRA has good radiation characteristics, where its gain and radiation efficiency are 7 dBi and 79.35%, respectively. These properties are reasonably constant over the working frequency bandwidth of the antenna. The return loss bandwidth was 2.23 GHz, which corresponds to 3.78% around 60 GHz. The antenna was primarily a broadside radiator with -15 dB cross polarization level.

Rational Organization of Lanthanide-Based SMM Dimers into Three-Dimensional Networks.

Science.gov (United States)

Yi, Xiaohui; Calvez, Guillaume; Daiguebonne, Carole; Guillou, Olivier; Bernot, Kevin

2015-06-01

Optimization of the reaction of [Ln(hfac)3]·2H2O and pyridine-N-oxide (PyNO), which is known to afford double-bridged dimers, leads to triple-bridged dimers of formula [(Ln(hfac)3)2(PyNO)3] (Ln = Gd (1), Dy (2)) from which the Dy derivative (2) behaves as a single-molecule magnet (SMM). The pseudo threefold axis symmetry of this zero-dimensional building block makes possible its extension into a tridimensional network. By changing PyNO for 4,4'-bipyridine N,N'-dioxide (4,4'BipyNO) a tridimensional compound of formula {[Ln(hfac)3]2(4,4'BipyNO)2]} (Ln = Eu (3), Gd (4), and Dy (5)) is then rationally obtained. This covalent three-dimensional (3D) network has a remarkably high cell volume (V = 24 419 A(3)) and is an arrangement of interpenetrated 3D subnetworks whose triple-bridged dimers still behave as SMMs.

A Micromachined Piezoresistive Pressure Sensor with a Shield Layer

Science.gov (United States)

Cao, Gang; Wang, Xiaoping; Xu, Yong; Liu, Sheng

2016-01-01

This paper presents a piezoresistive pressure sensor with a shield layer for improved stability. Compared with the conventional piezoresistive pressure sensors, the new one reported in this paper has an n-type shield layer that covers p-type piezoresistors. This shield layer aims to minimize the impact of electrical field and reduce the temperature sensitivity of piezoresistors. The proposed sensors have been successfully fabricated by bulk-micromachining techniques. A sensitivity of 0.022 mV/V/kPa and a maximum non-linearity of 0.085% FS are obtained in a pressure range of 1 MPa. After numerical simulation, the role of the shield layer has been experimentally investigated. It is demonstrated that the shield layer is able to reduce the drift caused by electrical field and ambient temperature variation. PMID:27529254

Capacitive micromachined ultrasonic transducers for medical imaging and therapy

International Nuclear Information System (INIS)

Khuri-Yakub, Butrus T; Oralkan, Ömer

2011-01-01

Capacitive micromachined ultrasonic transducers (CMUTs) have been subject to extensive research for the last two decades. Although they were initially developed for air-coupled applications, today their main application space is medical imaging and therapy. This paper first presents a brief description of CMUTs, their basic structure and operating principles. Our progression of developing several generations of fabrication processes is discussed with an emphasis on the advantages and disadvantages of each process. Monolithic and hybrid approaches for integrating CMUTs with supporting integrated circuits are surveyed. Several prototype transducer arrays with integrated front-end electronic circuits we developed and their use for 2D and 3D, anatomical and functional imaging, and ablative therapies are described. The presented results prove the CMUT as a micro-electro-mechanical systems technology for many medical diagnostic and therapeutic applications

Capacitive micromachined ultrasonic transducers for medical imaging and therapy.

Science.gov (United States)

Khuri-Yakub, Butrus T; Oralkan, Omer

2011-05-01

Capacitive micromachined ultrasonic transducers (CMUTs) have been subject to extensive research for the last two decades. Although they were initially developed for air-coupled applications, today their main application space is medical imaging and therapy. This paper first presents a brief description of CMUTs, their basic structure, and operating principles. Our progression of developing several generations of fabrication processes is discussed with an emphasis on the advantages and disadvantages of each process. Monolithic and hybrid approaches for integrating CMUTs with supporting integrated circuits are surveyed. Several prototype transducer arrays with integrated frontend electronic circuits we developed and their use for 2-D and 3-D, anatomical and functional imaging, and ablative therapies are described. The presented results prove the CMUT as a MEMS technology for many medical diagnostic and therapeutic applications.

Sustainable Materials Management (SMM) Web Academy Webinar: Advancing Sustainable Materials Management: Facts and Figures 2013 - Assessing Trends in Materials Generation, Recycling and Disposal in the United States

Science.gov (United States)

This is a webinar page for the Sustainable Management of Materials (SMM) Web Academy webinar titled Let’s WRAP (Wrap Recycling Action Program): Best Practices to Boost Plastic Film Recycling in Your Community

Mixed (phthalocyaninato)(Schiff-base) di-dysprosium sandwich complexes. Effect of magnetic coupling on the SMM behavior.

Science.gov (United States)

Wang, Hailong; Liu, Chenxi; Liu, Tao; Zeng, Suyuan; Cao, Wei; Ma, Qi; Duan, Chunying; Dou, Jianmin; Jiang, Jianzhuang

2013-11-21

Reaction between Schiff-base ligand and half-sandwich complex M(Pc)(acac) led to the isolation of new sandwich-type mixed (phthalocyaninato)(Schiff-base) di-lanthanide compounds M2(Pc)2(L)H2O (M = Dy, Gd) (1, 2) [H2Pc = metal free phthalocyanine, Hacac = acetylacetone, H2L = N,N'-bis(3-methyloxysalicylidene)benzene-1,2-diamine] with the triple-decker molecular structure clearly revealed by single crystal X-ray diffraction analysis. For the comparative studies, sandwich triple-decker analogues with pure Schiff-base ligand M2(L)3H2O (M = Dy, Gd) (3, 4) were also prepared. Dynamic magnetic measurement result reveals the single-molecule magnet (SMM) nature of the di-dysprosium derivative 1, while the static magnetic investigation over both pure and the diamagnetic diluted samples of this compound discloses the interionic ferromagnetic coupling between the two dysprosium ions, which in turn effectively suppresses the QTM and enhances the energy barrier of this SMM. Nevertheless, comparative studies over the static magnetic properties of the di-dysprosium triple-decker complexes 1 and 3 indicate the stronger magnetic coupling between the two lanthanide ions in mixed (phthalocyaninato)(Schiff-base) species than in the pure Schiff-base triple-decker analogue, suggesting the special coordination sphere around the dysprosium ions in the former compound over the latter one on the more intense inter-ionic ferromagnetic coupling. As a very small step towards understanding the structure-property relationship, the present result will be surely helpful for the design and synthesis of the multinuclear lanthanide-based SMMs with good properties.

Utilization of the UV laser with picosecond pulses for the formation of surface microstructures on elastomeric plastics

Science.gov (United States)

Antoszewski, B.; Tofil, S.; Scendo, M.; Tarelnik, W.

2017-08-01

Elastomeric plastics belong to a wide range of polymeric materials with special properties. They are used as construction material for seals and other components in many branches of industry and, in particular, in the biomedical industry, mechatronics, electronics and chemical equipment. The micromachining of surfaces of these materials can be used to build micro-flow, insulating, dispensing systems and chemical and biological reactors. The paper presents results of research on the effects of micro-machining of selected elastomeric plastics using a UV laser emitting picosecond pulses. The authors see the prospective application of the developed technology in the sealing technique in particular to shaping the sealing pieces co-operating with the surface of the element. The result of the study is meant to show parameters of the UV laser’s performance when producing typical components such as grooves, recesses for optimum ablation in terms of quality and productivity.

Achievement report for fiscal 1996 on the research and development of micromachine technology. Development of advanced-function maintenance technology for power generation facilities; 1996 nendo micromachine gijutsu no kenkyu kaihatsu seika hokokusho. Hatsuden shisetsuyo kokino maintenance gijutsu kaihatsu

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

Technologies for integrating functions are studied for a self-propelled surroundings recognition system that travels in a small-diameter tube at power generation facilities. Parameters are analyzed, and piezoelectric locomotion devices are reduced in size. A disk shape microantenna is experimentally built and evaluated, which is for realizing energy supply and communication by means of microwaves. Studies are conducted to improve the performance of optical energy transmission devices and to realize their systematization. Basic specifications are established for the embodiment of CCD (charge coupled device) microcameras to be installed. A high-efficiency, high-reliability micromachine system is constructed, in which multiple machines coordinate with each other for the exterior inspection of groups of small-diameter tubes. Devices which are capable of driving, deceleration, and propulsion prove to be feasible. Basic specifications are established for microconnectors to connect, separate, and combine multiple machines as occasion calls. Also discussed is the development of a micromachine for tube interior check and repair which operates making use of the inspection hole enabling tube interior check and repair without the need of disassembling the equipment to be repaired.

Determination of young's modulus of PZT and CO80Ni20 thin films by means of micromachined cantilevers

NARCIS (Netherlands)

Nazeer, H.; Abelmann, Leon; Tas, Niels Roelof; van Honschoten, J.W.; Siekman, Martin Herman; Elwenspoek, Michael Curt

2009-01-01

This paper presents a technique to determine the Young’s modulus and residual stress of thin films using a simple micromachined silicon cantilever as the test structure. An analytical relation was developed based on the shift in resonance frequency caused by the addition of a thin film on the

Design and fabrication of PMMA-micromachined fluid lens based on electromagnetic actuation on PMMA–PDMS bonded membrane

International Nuclear Information System (INIS)

Lee, June Kyoo; Park, Kyung-Woo; Choi, Ju Chan; Kim, Hak-Rin; Kong, Seong Ho

2012-01-01

The fabrication of a poly(methyl methacrylate) (PMMA)-micromachined fluid lens with an optimally designed built-in electromagnetic actuator was demonstrated in this study. Through a finite element method, the number of winding turns and the distance between magnetic moments were estimated to design an effective and miniaturized electromagnetic actuator. The lens body composed of PMMA structures was simply and rapidly micromachined using computer numerical control micro-milling. The poly(dimethylsiloxane) (PDMS) membranes for electromagnetic actuation were bonded to the PMMA structures by using the proposed PMMA–PDMS bonding technique, which uses an SiO 2 intermediate layer. A physical repulsive force produced by the electromagnetic actuator applies a controllable fluidic pressure to a fluidic chamber that is sealed with the PDMS membrane, thus allowing dynamic focusing. The focus tunability of the fabricated lens was 67 diopters with a focus hysteresis of less than 1 mm and a response time of 2 ms. The solenoid of the built-in actuator showed negligible thermal crosstalk to the lens. (paper)

Sustainable Materials Management (SMM) Web Academy Webinar: Changing How We Think About Our Resources for a Better Tomorrow: How to Donate Surplus Food from K-12 Schools

Science.gov (United States)

This is a webinar page for the Sustainable Management of Materials (SMM) Web Academy webinar titled Changing How We Think About Our Resources for a Better Tomorrow: How to Donate Surplus Food from K-12 Schools

Manufacture of Radio Frequency Micromachined Switches with Annealing

Directory of Open Access Journals (Sweden)

Cheng-Yang Lin

2014-01-01

Full Text Available The fabrication and characterization of a radio frequency (RF micromachined switch with annealing were presented. The structure of the RF switch consists of a membrane, coplanar waveguide (CPW lines, and eight springs. The RF switch is manufactured using the complementary metal oxide semiconductor (CMOS process. The switch requires a post-process to release the membrane and springs. The post-process uses a wet etching to remove the sacrificial silicon dioxide layer, and to obtain the suspended structures of the switch. In order to improve the residual stress of the switch, an annealing process is applied to the switch, and the membrane obtains an excellent flatness. The finite element method (FEM software CoventorWare is utilized to simulate the stress and displacement of the RF switch. Experimental results show that the RF switch has an insertion loss of 0.9 dB at 35 GHz and an isolation of 21 dB at 39 GHz. The actuation voltage of the switch is 14 V.

Manufacture of radio frequency micromachined switches with annealing.

Science.gov (United States)

Lin, Cheng-Yang; Dai, Ching-Liang

2014-01-17

The fabrication and characterization of a radio frequency (RF) micromachined switch with annealing were presented. The structure of the RF switch consists of a membrane, coplanar waveguide (CPW) lines, and eight springs. The RF switch is manufactured using the complementary metal oxide semiconductor (CMOS) process. The switch requires a post-process to release the membrane and springs. The post-process uses a wet etching to remove the sacrificial silicon dioxide layer, and to obtain the suspended structures of the switch. In order to improve the residual stress of the switch, an annealing process is applied to the switch, and the membrane obtains an excellent flatness. The finite element method (FEM) software CoventorWare is utilized to simulate the stress and displacement of the RF switch. Experimental results show that the RF switch has an insertion loss of 0.9 dB at 35 GHz and an isolation of 21 dB at 39 GHz. The actuation voltage of the switch is 14 V.

Fabrication of Microhotplates Based on Laser Micromachining of Zirconium Oxide

Science.gov (United States)

Oblov, Konstantin; Ivanova, Anastasia; Soloviev, Sergey; Samotaev, Nikolay; Lipilin, Alexandr; Vasiliev, Alexey; Sokolov, Andrey

We present a novel approach to the fabrication of MEMS devices, which can be used for gas sensors operating in harsh environment in wireless and autonomous information systems. MEMS platforms based on ZrO2/Y2O3 (YSZ) are applied in these devices. The methods of ceramic MEMS devices fabrication with laser micromachining are considered. It is shown that the application of YSZ membranes permits a decrease in MEMS power consumption at 4500C down to ∼75 mW at continuous heating and down to ∼ 1 mW at pulse heating mode. The application of the platforms is not restricted by gas sensors: they can be used for fast thermometers, bolometric matrices, flowmeteres and other MEMS devices working under harsh environmental conditions.

Synthesis and SMM behaviour of trinuclear versus dinuclear 3d-5f uranyl(v)-cobalt(ii) cation-cation complexes.

Science.gov (United States)

Chatelain, Lucile; Tuna, Floriana; Pécaut, Jacques; Mazzanti, Marinella

2017-05-02

Trinuclear versus dinuclear heterodimetallic U V O 2 + Co 2+ complexes were selectively assembled via a cation-cation interaction by tuning the ligand. The trimeric complex 2, with a linear [Co-O[double bond, length as m-dash]U[double bond, length as m-dash]O-Co] core, exhibits magnetic exchange and slow relaxation with a reversal barrier of 30.5 ± 0.9 K providing the first example of a U-Co exchange-coupled SMM.

Analysis of ultraviolet and X-ray observations of three homologous solar flares from SMM

Science.gov (United States)

Cheng, Chung-Chieh; Pallavicini, Roberto

1987-01-01

Three homologous flares observed in the UV lines of Fe XXI and O V and in X-rays from the SMM were studied. It was found that: (1) the homology of the flares was most noticeable in Fe XXI and soft X-ray emissions; (2) the three flares shared many of the same loop footprints which were located in O V bright kernals associated with hard X-ray bursts; and (3) in spite of the strong spatial homology, the temporal evolution in UV and X-ray emissions varied from flare to flare. A comparison between the UV observations and photospheric magnetograms revealed that the basic flare configuration was a complex loop system consisting of many loops or bundles of loops.

A bulk micromachined lead zinconate titanate cantilever energy harvester with inter-digital IrO(x) electrodes.

Science.gov (United States)

Park, Jongcheol; Park, Jae Yeong

2013-10-01

A piezoelectric vibration energy harvester with inter-digital IrO(x) electrode was developed by using silicon bulk micromachining technology. Most PZT cantilever based energy harvesters have utilized platinum electrode material. However, the PZT fatigue characteristics and adhesion/delamination problems caused by the platinum electrode might be serious problem in reliability of energy harvester. To address these problems, the iridium oxide was newly applied. The proposed energy harvester was comprised of bulk micromachined silicon cantilever with 800 x 1000 x 20 microm3, which having a silicon supporting membrane, sol-gel-spin coated Pb(Zr52, Ti48)O3 thin film, and sputtered inter-digitally shaped IrO(x) electrodes, and silicon inertial mass with 1000 x 1000 x 500 microm3 to adjust its resonant frequency. The fabricated energy harvester generated 1 microW of electrical power to 470 komega of load resistance and 1.4 V(peak-to-peak) from a vibration of 0.4 g at 1.475 kHz. The corresponding power density was 6.25 mW x cm(-3) x g(-2). As expected, its electrical failure was significantly improved.

A Massive Molecular Gas Reservoir in the Z = 2.221 Type-2 Quasar Host Galaxy SMM J0939+8315 Lensed by the Radio Galaxy 3C220.3

Science.gov (United States)

Leung, T. K. Daisy; Riechers, Dominik A.

2016-02-01

We report the detection of CO(J = 3 \\to 2) line emission in the strongly lensed submillimeter galaxy (SMG) SMM J0939+8315 at z = 2.221, using the Combined Array for Research in Millimeter-wave Astronomy. SMM J0939+8315 hosts a type-2 quasar, and is gravitationally lensed by the radio galaxy 3C220.3 and its companion galaxy at z = 0.685. The 104 GHz continuum emission underlying the CO line is detected toward 3C220.3 with an integrated flux density of Scont = 7.4 ± 1.4 mJy. Using the CO(J = 3 \\to 2) line intensity of ICO(3-2) = (12.6 ± 2.0) Jy km s-1, we derive a lensing- and excitation-corrected CO line luminosity of {L}{{CO(1-0)}}\\prime = (3.4 ± 0.7) × 1010 (10.1/μL) K km s-1 pc2 for the SMG, where μL is the lensing magnification factor inferred from our lens modeling. This translates to a molecular gas mass of Mgas = (2.7 ± 0.6) × 1010 (10.1/μL) M⊙. Fitting spectral energy distribution models to the (sub)-millimeter data of this SMG yields a dust temperature of T = 63.1{}-1.3+1.1 K, a dust mass of Mdust = (5.2 ± 2.1) × 108 (10.1/μL) M⊙, and a total infrared luminosity of LIR = (9.1 ± 1.2) ×1012 (10.1/μL) L⊙. We find that the properties of the interstellar medium of SMM J0939+8315 overlap with both SMGs and type-2 quasars. Hence, SMM J0939+8315 may be transitioning from a starbursting phase to an unobscured quasar phase as described by the “evolutionary link” model, according to which this system may represent an intermediate stage in the evolution of present-day galaxies at an earlier epoch.

Infra-red laser ablative micromachining of parylene-C on SiO2 substrates for rapid prototyping, high yield, human neuronal cell patterning

International Nuclear Information System (INIS)

Raos, B J; Unsworth, C P; Costa, J L; Rohde, C A; Simpson, M C; Doyle, C S; Dickinson, M E; Bunting, A S; Murray, A F; Delivopoulos, E; Graham, E S

2013-01-01

Cell patterning commonly employs photolithographic methods for the micro fabrication of structures on silicon chips. These require expensive photo-mask development and complex photolithographic processing. Laser based patterning of cells has been studied in vitro and laser ablation of polymers is an active area of research promising high aspect ratios. This paper disseminates how 800 nm femtosecond infrared (IR) laser radiation can be successfully used to perform laser ablative micromachining of parylene-C on SiO 2 substrates for the patterning of human hNT astrocytes (derived from the human teratocarcinoma cell line (hNT)) whilst 248 nm nanosecond ultra-violet laser radiation produces photo-oxidization of the parylene-C and destroys cell patterning. In this work, we report the laser ablation methods used and the ablation characteristics of parylene-C for IR pulse fluences. Results follow that support the validity of using IR laser ablative micromachining for patterning human hNT astrocytes cells. We disseminate the variation in yield of patterned hNT astrocytes on parylene-C with laser pulse spacing, pulse number, pulse fluence and parylene-C strip width. The findings demonstrate how laser ablative micromachining of parylene-C on SiO 2 substrates can offer an accessible alternative for rapid prototyping, high yield cell patterning with broad application to multi-electrode arrays, cellular micro-arrays and microfluidics. (paper)

SMM observation of a cosmic gamma-ray burst from 20 keV to 100 MeV

Science.gov (United States)

Share, G. H.; Matz, S. M.; Messina, D. C.; Nolan, P. L.; Chupp, E. L.

1986-01-01

The Solar Maximum Mission gamma-ray spectrometer has detected an intense gamma-ray burst that occurred on August 5, 1984. The burst originated from a source in the constellation Hydra and lasted about 45 s. Its integral fluence at 20 keV was 0.003 erg/sq cm. Spectral evolution similar to other bursts detected by SMM was observed. The overall shape of the spectrum from 20 keV to 100 MeV, on timescales as short as 2 s, is relatively constant. This shape can be fitted by the sum of an exponential-type function and a power law. There is no evidence for narrow or broadened emission lines.

Heavy ion beam micromachining on LiNbO3

International Nuclear Information System (INIS)

Nesprias, F.; Venturino, M.; Debray, M.E.; Davidson, J.; Davidson, M.; Kreiner, A.J.; Minsky, D.; Fischer, M.; Lamagna, A.

2009-01-01

In this work 3D micromachining of x-cut lithium niobate crystals was performed using the high energy heavy ion microbeam (HIM) at the Tandar Laboratory, Buenos Aires. The samples were machined using 35 Cl beams at 70 MeV bombarding energy combined with wet etching with hydrofluoric acid solutions at room temperature. As the ion beam penetrates the sample, it induces lattice damage increasing dramatically the local etching rate of the material. This technique was applied to the fabrication of 3D waveguides with long control electrodes. The resulting structures indicate that well defined contours with nearly vertical sidewalls can be made. The results also show that with fluences of only 5 x 10 12 ions/cm 2 , this technique is suitable for the fabrication of different shapes of LiNbO 3 control-waveguides that can be used in different optical devices and matched with the existing optical fibers.

Advanced measurement and analysis of surface textures produced by micro-machining processes

International Nuclear Information System (INIS)

Bordatchev, Evgueni V; Hafiz, Abdullah M K

2014-01-01

Surface texture of a part or a product has significant effects on its functionality, physical-mechanical properties and visual appearance. In particular for miniature products, the implication of surface quality becomes critical owing to the presence of geometrical features with micro/nano-scale dimensions. Qualitative and quantitative assessments of surface texture are carried out predominantly by profile parameters, which are often insufficient to address the contribution of constituent spatial components with varied amplitudes and wavelengths. In this context, this article presents a novel approach for advanced measurement and analysis of profile average roughness (R a ) and its spatial distribution at different wavelength intervals. The applicability of the proposed approach was verified for three different surface topographies prepared by grinding, laser micro-polishing and micro-milling processes. From the measurement and analysis results, R a (λ) spatial distribution was found to be an effective measure of revealing the contributions of various spatial components within specific wavelength intervals towards formation of the entire surface profile. In addition, the approach was extended to the measurement and analysis of areal average roughness S a (λ) spatial distribution within different wavelength intervals. Besides, the proposed method was demonstrated to be a useful technique in developing a functional correlation between a manufacturing process and its corresponding surface profile. (paper)

Silicon Micromachining in RF and Photonic Applications

Science.gov (United States)

Lin, Tsen-Hwang; Congdon, Phil; Magel, Gregory; Pang, Lily; Goldsmith, Chuck; Randall, John; Ho, Nguyen

1995-01-01

Texas Instruments (TI) has developed membrane and micromirror devices since the late 1970s. An eggcrate space membrane was used as the spatial light modulator in the early years. Discrete micromirrors supported by cantilever beams created a new era for micromirror devices. Torsional micromirror and flexure-beam micromirror devices were promising for mass production because of their stable supports. TI's digital torsional micromirror device is an amplitude modulator (known as the digital micromirror device (DMD) and is in production development, discussed elsewhere. We also use a torsional device for a 4 x 4 fiber-optic crossbar switch in a 2 cm x 2 cm package. The flexure-beam micromirror device is an analog phase modulator and is considered more efficient than amplitude modulators for use in optical processing systems. TI also developed millimeter-sized membranes for integrated optical switches for telecommunication and network applications. Using a member in radio frequency (RF) switch applications is a rapidly growing area because of the micromechanical device performance in microsecond-switching characteristics. Our preliminary membrane RF switch test structure results indicate promising speed and RF switching performance. TI collaborated with MIT for modeling of metal-based micromachining.

Ultrasonic actuation for MEMS dormancy-related stiction reduction

Science.gov (United States)

Kaajakari, Ville; Kan, Shyi-Herng; Lin, Li-Jen; Lal, Amit; Rodgers, M. Steven

2000-08-01

The use of ultrasonic pulses incident on surface micromachines has been shown to reduce dormancy-related failure. We applied ultrasonic pulses from the backside of a silicon substrate carrying SUMMiT processed surface micromachined rotors, used earlier as ultrasonic motors. The amplitude of the pulses was less than what is required to actuate the rotor (sub-threshold actuation). By controlling the ultrasonic pulse exposure time it was found that pulsed samples had smaller actuation voltages as compared to non-pulsed samples after twelve-hour dormancy. This result indicates that the micromachine stiction to surfaces during dormant period can be effectively eliminated, resulting in long-term stability of surface micromachines in critical applications.

Sustainable Materials Management (SMM) Web Academy Webinar: State Policies to Increase Organics Diversion from Landfills: MA and VT one year in and CA the new kid on the block

Science.gov (United States)

This is a webinar page for the Sustainable Management of Materials (SMM) Web Academy webinar titled Changing How We Think About Our Resources for a Better Tomorrow: How to Donate Surplus Food from K-12 Schools

A surface-micromachining-based inertial micro-switch with compliant cantilever beam as movable electrode for enduring high shock and prolonging contact time

Energy Technology Data Exchange (ETDEWEB)

Xu, Qiu [National Key Laboratory of Science and Technology on Micro/Nano Fabrication, School of Electronics Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai, 200240 (China); Yang, Zhuoqing, E-mail: yzhuoqing@sjtu.edu.cn [National Key Laboratory of Science and Technology on Micro/Nano Fabrication, School of Electronics Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai, 200240 (China); Fu, Bo; Li, Jianhua; Wu, Hao [Huaihai Industrial Group Co., Ltd., Changzhi, Shanxi Province, 046012 (China); Zhang, Qihuan; Sun, Yunna; Ding, Guifu; Zhao, Xiaolin [National Key Laboratory of Science and Technology on Micro/Nano Fabrication, School of Electronics Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai, 200240 (China)

2016-11-30

Highlights: • The designed cantilever beam attached to the proof mass can endure a larger shock acceleration (∼1000 g order of magnitude) compared to those traditional designs (∼100 g order of magnitude). • Effect of the pulse width on the threshold acceleration, the response time and the contact time is investigated. • A constraint sleeve structure is introduced to lower the off-axis sensitivity. - Abstract: A novel laterally-driven inertial micro-switch with two L-shaped elastic cantilever beams as the movable electrode, which is attached to the proof mass, is proposed in this paper. The advantage of this design is that the contact time of the inertial micro-switch can be prolonged. Meanwhile, the micro-switch can withstand a higher shock than the traditional designs whose cantilever beams are attached to the fixed electrode. The designed inertial micro-switch was simulated and optimized with ANSYS software and fabricated on a quartz substrate by surface micromachining technology. The simulated result demonstrates that the threshold acceleration (a{sub ths}) under stable switch-on state is about 288 g and the contact time is about 198 μs when the pulse width of acceleration loads is 1 ms. At the same time, it indicates that the threshold acceleration, the response time and the contact time of designed micro-switch all increase with the pulse width of acceleration loads. The simulation of impact process in non-sensitive direction shows that the introduced constraint sleeve structure in the novel inertial micro-switch can lower the off-axis sensitivity. The fabricated micro-switch prototype has been tested by a standard dropping hammer system under shock accelerations with various amplitudes and pulse widths. The experimental measurements show that the contact time is about 150 μs when the threshold acceleration is about 288 g. It also indicates that the response time and the contact time both increase with the pulse width, which is consistent with the

Dilution-triggered SMM behavior under zero field in a luminescent Zn2Dy2 tetranuclear complex incorporating carbonato-bridging ligands derived from atmospheric CO2 fixation.

Science.gov (United States)

Titos-Padilla, Silvia; Ruiz, José; Herrera, Juan Manuel; Brechin, Euan K; Wersndorfer, Wolfgang; Lloret, Francesc; Colacio, Enrique

2013-08-19

The synthesis, structure, magnetic, and luminescence properties of the Zn2Dy2 tetranuclear complex of formula {(μ3-CO3)2[Zn(μ-L)Dy(NO3)]2}·4CH3OH (1), where H2L is the compartmental ligand N,N',N″-trimethyl-N,N″-bis(2-hydroxy-3-methoxy-5-methylbenzyl)diethylenetriamine, are reported. The carbonate anions that bridge two Zn(μ-L)Dy units come from the atmospheric CO2 fixation in a basic medium. Fast quantum tunneling relaxation of the magnetization (QTM) is very effective in this compound, so that single-molecule magnet (SMM) behavior is only observed in the presence of an applied dc field of 1000 Oe, which is able to partly suppress the QTM relaxation process. At variance, a 1:10 Dy:Y magnetic diluted sample, namely, 1', exhibits SMM behavior at zero applied direct-current (dc) field with about 3 times higher thermal energy barrier than that in 1 (U(eff) = 68 K), thus demonstrating the important role of intermolecular dipolar interactions in favoring the fast QTM relaxation process. When a dc field of 1000 Oe is applied to 1', the QTM is almost fully suppressed, the reversal of the magnetization slightly slows, and U(eff) increases to 78 K. The dilution results combined with micro-SQUID magnetization measurements clearly indicate that the SMM behavior comes from single-ion relaxation of the Dy(3+) ions. Analysis of the relaxation data points out that a Raman relaxation process could significantly affect the Orbach relaxation process, reducing the thermal energy barrier U(eff) for slow relaxation of the magnetization.

The SMM UV observations of Active Region 5395

Science.gov (United States)

Drake, Stephen A.; Gurman, Joseph B.

1989-01-01

The Ultraviolet Spectrometer and Polarimeter (UVSP) on the Solar Maximum Mission (SMM) spacecraft was used extensively to study the spatial morphology and time variability of solar active regions in the far UV (at approx. wavelength of 1370 A) since July 1985. The normal spatial resolution of UVSP observations in this 2nd-order mode is 10 sec., and the highest temporal resolution is 64 milliseconds. To make a full-field, 4 min. by 4 min. image this wavelength using 5 sec. raster steps takes about 3 minutes. UVSP can also make observations of the Sun at approx. wavelength of 2790 with 3 sec. spatial resolution when operated in its 1st-order mode; a full-field image at this wavelength (a so-called SNEW image) takes about 8 minutes. UVSP made thousands of observations (mostly in 2nd-order) of AR 5395 during its transit across the visible solar hemisphere (from 7 to 19 March, inclusive). During this period, UVSP's duty cycle for observing AR 5395 was roughly 40 percent, with the remaining 60 percent of the time being fairly evenly divided between aeronomy studies of the Earth's atmosphere and dead time due to Earth occultation of the Sun. UVSP observed many of the flares tagged to AR 5395, including 26 GOES M-level flares and 3 X-level flares, one of which produced so much UV emission that the safety software of UVSP turned off the detector to avoid damage due to saturation. Images and light curves of some of the more spectacular of the AR 5395 events are presented.

UV laser micromachining of piezoelectric ceramic using a pulsed Nd:YAG laser

International Nuclear Information System (INIS)

Zeng, D.W.; Xie, C.S.; Li, K.; Chan, H.L.W.; Choy, C.L.; Yung, K.C.

2004-01-01

UV laser (λ=355 nm) ablation of piezoelectric lead zirconate titanate (PZT) ceramics in air has been investigated under different laser parameters. It has been found that there is a critical pulse number (N=750). When the pulse number is smaller than the critical value, the ablation rate decreases with increasing pulse number. Beyond the critical value, the ablation rate becomes constant. The ablation rate and concentrations of O, Zr and Ti on the ablated surface increase with the laser fluence, while the Pb concentration decreases due to the selective evaporation of PbO. The loss of the Pb results in the formation of a metastable pyrochlore phase. ZrO 2 was detected by XPS in the ablated zone. Also, the concentrations of the pyrochlore phase and ZrO 2 increase with increasing laser fluence. These results clearly indicate that the chemical composition and phase structure in the ablated zone strongly depend on the laser fluence. The piezoelectric properties of the cut PZT ceramic samples completely disappear due to the loss of the Pb and the existence of the pyrochlore phase. After these samples were annealed at 1150 C for 1 h in a PbO-controlled atmosphere, their phase structure and piezoelectric properties were recovered again. Finally, 1-3 and concentric-ring 2-2 PZT/epoxy composites were fabricated by UV laser micromachining and their thickness modes were measured by impedance spectrum analysis and a d 33 meter. Both composites show high piezoelectric properties. (orig.)

A fully packaged micromachined single crystalline resonant force sensor

Energy Technology Data Exchange (ETDEWEB)

Cavalloni, C.; Gnielka, M.; Berg, J. von [Kistler Instrumente AG, Winterthur (Switzerland); Haueis, M.; Dual, J. [ETH Zuerich, Inst. of Mechanical Systems, Zuerich (Switzerland); Buser, R. [Interstate Univ. of Applied Science Buchs, Buchs (Switzerland)

2001-07-01

In this work a fully packaged resonant force sensor for static load measurements is presented. The working principle is based on the shift of the resonance frequency in response to the applied load. The heart of the sensor, the resonant structure, is fabricated by micromachining using single crystalline silicon. To avoid creep and hysteresis and to minimize temperature induced stress the resonant structure is encapsulated using an all-in-silicon solution. This means that the load coupling, the excitation of the microresonator and the detection of the oscillation signal are integrated in only one single crystalline silicon chip. The chip is packaged into a specially designed housing made of steel which has been designed with respect to application in harsh environments. The unloaded sensor has an initial frequency of about 22,5 kHz. The sensitivity amounts to 26 Hz/N with a linearity error significantly less than 0,5%FSO. (orig.)

Micromachined force sensors using thin film nickel–chromium piezoresistors

International Nuclear Information System (INIS)

Nadvi, Gaviraj S; Butler, Donald P; Çelik-Butler, Zeynep; Gönenli, İsmail Erkin

2012-01-01

Micromachined force/tactile sensors using nickel–chromium piezoresistors have been investigated experimentally and through finite-element analysis. The force sensors were designed with a suspended aluminum oxide (Al 2 O 3 ) membrane and optimally placed piezoresistors to measure the strain in the membrane when deflected with an applied force. Different devices, each with varying size and shape of both the membrane and the piezoresistors, were designed, fabricated and characterized. The piezoresistors were placed into a half-Wheatstone bridge configuration with two active and two passive nickel–chromium resistors to provide temperature drift compensation. The force sensors were characterized using a load cell and a nanopositioner to measure the sensor response with applied load. Piezoresistive gauge factors in the range of 1–5.2 have been calculated for the thin film nichrome (NiCr 80/20 wt%) from the measured results. The force sensors were calculated to have a noise equivalent force of 65–245 nN. (paper)

Performance Enhancement of the Patch Antennas Applying Micromachining Technology

Directory of Open Access Journals (Sweden)

Mohamed N. Azermanesh

2007-09-01

Full Text Available This paper reports on the application of micromachining technology for performance enhancement of two types of compact antennas which are becoming a common practice in microsystems. Shorted patch antennas (SPA and folded shorted patch antennas operating in the 5-6 GHz ISM band, with intended application in short-range wireless communications, are considered. The electrical length of antennas are modified by etching the substrate of the antennas, thus providing a new degree of freedom to control the antenna operating properties, which is the main novelty of our work. The gain and bandwidth of the antennas are increased by increasing the etching depth. However, etching the substrate affects the operating frequency as well. To keep the operating frequency at a pre-specified value, the dimension of the antennas must be increased by deepening the etching depth. Therefore, a trade off between the performance enhancement of the antennas and the dimensional enlargement is required.

Micro-machinable polymer-derived ceramic sensors for high-temperature applications

Science.gov (United States)

Liu, Jian; Xu, Chengying; An, Linan

2010-04-01

Micro-sensors are highly desired for on-line temperature/pressure monitoring in turbine engines to improve their efficiency and reduce pollution. The biggest challenge for developing this type of sensors is that the sensors have to sustain at extreme environments in turbine engine environments, such as high-temperatures (>800 °C), fluctuated pressure and oxidation/corrosion surroundings. In this paper, we describe a class of sensors made of polymer-derived ceramics (PDCs) for such applications. PDCs have the following advantages over conventional ceramics, making them particularly suitable for these applications: (i) micromachining capability, (ii) tunable electric properties, and (iii) hightemperature capability. Here, we will discuss the materials and their properties in terms of their applications for hightemperature micro-sensors, and microfabrication technologies. In addition, we will also discuss the design of a heat-flux sensor based on polymer-derived ceramics.

Trend of advanced technology of micromachines in the USA; Beikoku ni okeru micro machine sentan gijutsu doko chosa hokokusho

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-03-01

In this research, the data of advanced technology of micromachines in the USA have been searched, collected, and arranged from the US patent information, technical journal information, and newspaper and general journal information. According to demand, the main undertaking information was interviewed from well-informed persons. The data were compiled as advanced technology trend of micromachines in the USA. Sensors are remarkably predominant in the elemental technology. There are also important topics in the fields of actuators, motors, lenses, devices, and structures. On the other hand, materials, etchings, packages, motive powers, and softwares are also important elemental technology in spite of their less information. From the viewpoint of usage, detection systems are remarkably predominant. Then, robots, processing systems, optics, analysis systems, motive power systems, medical systems, and acoustic systems are also important. From the viewpoint of industrial sector, the environmental items are predominant. Automobiles, medical treatments, and information communications follow the above. When new relationships to the secondary usage and tertiary usage are not found, it would be rather hard to express such a technology development trend more clearly.

Synthesis, Crystal Structures, Magnetic Properties, and Theoretical Investigation of a New Series of NiII-LnIII-WV Heterotrimetallics: Understanding the SMM Behavior of Mixed Polynuclear Complexes.

Science.gov (United States)

Vieru, Veacheslav; Pasatoiu, Traian D; Ungur, Liviu; Suturina, Elizaveta; Madalan, Augustin M; Duhayon, Carine; Sutter, Jean-Pascal; Andruh, Marius; Chibotaru, Liviu F

2016-12-05

The polynuclear compounds containing anisotropic metal ions often exhibit efficient barriers for blocking of magnetization at fairly arbitrary geometries. However, at variance with mononuclear complexes, which usually become single-molecule magnets (SMM) under the sole requirement of a highly axial crystal field at the metal ion, the factors influencing the SMM behavior in polynuclear complexes, especially, with weakly axial magnetic ions, still remain largely unrevealed. As an attempt to clarify these conditions, we present here the synthesis, crystal structures, magnetic behavior, and ab initio calculations for a new series of Ni II -Ln III -W V trimetallics, [(CN) 7 W(CN)Ni(H 2 O)(valpn)Ln(H 2 O) 4 ]·H 2 O (Ln = Y 1, Eu 2, Gd 3, Tb 4, Dy 5, Lu 6). The surprising finding is the absence of the magnetic blockage even for compounds involving strongly anisotropic Dy III and Tb III metal ions. This is well explained by ab initio calculations showing relatively large transversal components of the g-tensor in the ground exchange Kramers doublets of 1 and 4 and large intrinsic tunneling gaps in the ground exchange doublets of 3 and 5. In order to get more insight into this behavior, another series of earlier reported compounds with the same trinuclear [W V Ni II Ln III ] core structure, [(CN) 7 W(CN)Ni(dmf)(valdmpn)Ln(dmf) 4 ]·H 2 O (Ln = Gd III 7, Tb III 8a, Dy III 9, Ho III 10), [(CN) 7 W(CN)Ni(H 2 O)(valdmpn)Tb(dmf) 2.5 (H 2 O) 1.5 ]·H 2 O·0.5dmf 8b, and [(CN) 7 W(CN)Ni(H 2 O)(valdmpn)Er(dmf) 3 (H 2 O) 1 ]·H 2 O·0.5dmf 11, has been also investigated theoretically. In this series, only 8b exhibits SMM behavior which is confirmed by the present ab initio calculations. An important feature for the entire series is the strong ferromagnetic coupling between Ni(II) and W(V), which is due to an almost perfect trigonal dodecahedron geometry of the octacyano wolframate fragment. The reason why only 8b is an SMM is explained by positive zero-field splitting on the nickel

Sensors and Micromachined Devices for the Automotive and New Markets: The Delphi Delco Electronics MEMS Story.

Science.gov (United States)

Logsdon, James

2002-03-01

This presentation will provide a brief history of the development of MEMS products and technology, beginning with the manifold absolute pressure sensor in the late seventies through the current variety of Delphi Delco Electronics sensors available today. The technology development of micromachining from uncompensated P plus etch stops to deep reactive ion etching and the technology development of wafer level packaging from electrostatic bonding to glass frit sealing and silicon to silicon direct bonding will be reviewed.

The study of SMM as a virus strategy in the media space

Directory of Open Access Journals (Sweden)

V L Mouzykant

2014-12-01

Full Text Available The article describes the phenomenon of social marketing in the Internet that has changed the idea of the relationships between the addresser and the addressee in the social networks. The author analyzes the typology, genesis and consequences of the virus marketing in social networks from the perspective of the sociological analysis of media. The article considers the influence of the Internet on the behavior of the Russians, the methods of measuring the impact of the emerging new media. The author identifies different strategies in the SMM-market, such as creative content, digital-projects, media planning, simple content, government, close-to-government and educational projects. ROMIR within the GemuisAudience project conducted a research among 20 thousand Russian respondents to monitor their behavior in the sphere with the help of special sensors that identify Internet preferences of the Russians. The first results of the project revealed a trend - the more interesting the content the more likely the user is to share the app with his friends.

A Novel Silicon Micromachined Integrated MCM Thermal Management System

Science.gov (United States)

Kazmierczak, M. J.; Henderson, H. T.; Gerner, F. M.

1997-01-01

"Micromachining" is a chemical means of etching three-dimensional structures, typically in single- crystalline silicon. These techniques are leading toward what is coming to be referred to as MEMS (Micro Electro Mechanical Systems), where in addition to the ordinary two-dimensional (planar) microelectronics, it is possible to build three-dimensional n-ticromotors, electrically- actuated raicrovalves, hydraulic systems and much more on the same microchip. These techniques become possible because of differential etching rates of various crystallographic planes and materials used for semiconductor n-ticrofabfication. The University of Cincinnati group in collaboration with Karl Baker at NASA Lewis were the first to form micro heat pipes in silicon by the above techniques. Current work now in progress using MEMS technology is now directed towards the development of the next generation in MCM (Multi Chip Module) packaging. Here we propose to develop a complete electronic thermal management system which will allow densifica6on in chip stacking by perhaps two orders of magnitude. Furthermore the proposed technique will allow ordinary conu-nercial integrated chips to be utilized. Basically, the new technique involves etching square holes into a silicon substrate and then inserting and bonding commercially available integrated chips into these holes. For example, over a 100 1/4 in. by 1 /4 in. integrated chips can be placed on a 4 in. by 4 in. silicon substrate to form a Multi-Chip Module (MCM). Placing these MCM's in-line within an integrated rack then allows for three-diniensional stacking. Increased miniaturization of microelectronic circuits will lead to very high local heat fluxes. A high performance thermal management system will be specifically designed to remove the generated energy. More specifically, a compact heat exchanger with milli / microchannels will be developed and tested to remove the heat through the back side of this MCM assembly for moderate and high

Planar Indium Tin Oxide Heater for Improved Thermal Distribution for Metal Oxide Micromachined Gas Sensors

Directory of Open Access Journals (Sweden)

M. Cihan Çakır

2016-09-01

Full Text Available Metal oxide gas sensors with integrated micro-hotplate structures are widely used in the industry and they are still being investigated and developed. Metal oxide gas sensors have the advantage of being sensitive to a wide range of organic and inorganic volatile compounds, although they lack selectivity. To introduce selectivity, the operating temperature of a single sensor is swept, and the measurements are fed to a discriminating algorithm. The efficiency of those data processing methods strongly depends on temperature uniformity across the active area of the sensor. To achieve this, hot plate structures with complex resistor geometries have been designed and additional heat-spreading structures have been introduced. In this work we designed and fabricated a metal oxide gas sensor integrated with a simple square planar indium tin oxide (ITO heating element, by using conventional micromachining and thin-film deposition techniques. Power consumption–dependent surface temperature measurements were performed. A 420 °C working temperature was achieved at 120 mW power consumption. Temperature distribution uniformity was measured and a 17 °C difference between the hottest and the coldest points of the sensor at an operating temperature of 290 °C was achieved. Transient heat-up and cool-down cycle durations are measured as 40 ms and 20 ms, respectively.

Planar Indium Tin Oxide Heater for Improved Thermal Distribution for Metal Oxide Micromachined Gas Sensors.

Science.gov (United States)

Çakır, M Cihan; Çalışkan, Deniz; Bütün, Bayram; Özbay, Ekmel

2016-09-29

Metal oxide gas sensors with integrated micro-hotplate structures are widely used in the industry and they are still being investigated and developed. Metal oxide gas sensors have the advantage of being sensitive to a wide range of organic and inorganic volatile compounds, although they lack selectivity. To introduce selectivity, the operating temperature of a single sensor is swept, and the measurements are fed to a discriminating algorithm. The efficiency of those data processing methods strongly depends on temperature uniformity across the active area of the sensor. To achieve this, hot plate structures with complex resistor geometries have been designed and additional heat-spreading structures have been introduced. In this work we designed and fabricated a metal oxide gas sensor integrated with a simple square planar indium tin oxide (ITO) heating element, by using conventional micromachining and thin-film deposition techniques. Power consumption-dependent surface temperature measurements were performed. A 420 °C working temperature was achieved at 120 mW power consumption. Temperature distribution uniformity was measured and a 17 °C difference between the hottest and the coldest points of the sensor at an operating temperature of 290 °C was achieved. Transient heat-up and cool-down cycle durations are measured as 40 ms and 20 ms, respectively.

Micro-machined high-frequency (80 MHz) PZT thick film linear arrays.

Science.gov (United States)

Zhou, Qifa; Wu, Dawei; Liu, Changgeng; Zhu, Benpeng; Djuth, Frank; Shung, K

2010-10-01

This paper presents the development of a micromachined high-frequency linear array using PZT piezoelectric thick films. The linear array has 32 elements with an element width of 24 μm and an element length of 4 mm. Array elements were fabricated by deep reactive ion etching of PZT thick films, which were prepared from spin-coating of PZT sol-gel composite. Detailed fabrication processes, especially PZT thick film etching conditions and a novel transferring-and-etching method, are presented and discussed. Array designs were evaluated by simulation. Experimental measurements show that the array had a center frequency of 80 MHz and a fractional bandwidth (-6 dB) of 60%. An insertion loss of -41 dB and adjacent element crosstalk of -21 dB were found at the center frequency.

A study of solar preflare activity using two-dimensional radio and SMM-XRP observations

Science.gov (United States)

Kundu, M. R.; Gopalswamy, N.; Saba, J. L. R.; Schmelz, J. T. S.; Strong, K. T.

1987-01-01

A study of type III activity at meter-decameter wavelengths in the preflare phase of the February 3, 1986 flare is presented, using data obtained with the Clark Lake Multifrequency Radioheliograph. This activity is compared with similar type III burst activity during the impulsive phase, and it is found that there is a displacement of burst sources between the onset and end times of the activity. A comparison of this displacement at three frequencies suggests that the type III emitting electrons gain access progressively to diverging and different field lines relative to the initial field lines. The energetics of the type III emitting electrons are inferred from observations and compared with those of the associated hard X-ray emitting electrons. The soft X-ray data from SMM-XRP show enhanced emission measure, density, and temperature in the region associated with the preflare type III activity.

Fiscal 1993 report on technological results. R and D on micromachine technology; 1993 nendo micro machine gijutsu no kenkyu kaihatsu seika hokokusho

Energy Technology Data Exchange (ETDEWEB)

NONE

1994-12-01

Researches on basic element technology of micromachines are conducted with the view of establishing a mechanical system constituted of minute functional elements that perform autonomous operations in a narrow small part of complicated equipment in a power station for example or in a living body. The areas of activity are 1. research on micro actuators and 2. research on basic technology of micromachine; 1 is classified into researches of (1) shape-memory actuator, (2) bending and stretching type actuator, and (3) integrated micro actuator, while 2 is classified into researches of (1) total system for medical diagnosis, (2) micro tactile sensing technology and laser applied diagnosis/treatment technology, and (3) blood pressure/blood circulation sensing technology. In 1-(1), a chemo-mechanical actuator was studied using a shape memory alloy (SMA) and a high polymer gel, and in 1-(2), an SMA and bimetal were employed as a source of the driving force. Further, examination was also made on a fluid driving type actuator. (NEDO)

Diffusion-weighted imaging (b value = 1500 s/mm(2)) is useful to decrease false-positive breast cancer cases due to fibrocystic changes.

Science.gov (United States)

Ochi, Miho; Kuroiwa, Toshiro; Sunami, Shunya; Murakami, Junji; Miyahara, Shinichiro; Nagaie, Takashi; Oya, Masafumi; Yabuuchi, Hidetake; Hatakenaka, Masamitsu

2013-04-01

We aimed to evaluate the application of apparent diffusion coefficient (ADC) values calculated from diffusion-weighted imaging (DWI) (b value = 1500 s/mm(2)) in the breast imaging reporting and data system (BI-RADS). For 104 cases of breast lesions with definitive histology diagnosis (45 benign cases, 59 malignant cases) in which breast magnetic resonance imaging was performed, ADC values were compared between benign and malignant cases, between ductal carcinoma in situ (DCIS) and fibrocystic changes, and between DCIS and ductal hyperplasia (one type of fibrocystic change). Diagnostic accuracy was compared for a total of 101 images and for 34 images including only nine DCIS and 25 fibrocystic changes between BI-RADS alone (with categories 4a, 4b, and 5 defined as malignancies) and BI-RADS plus ADC. There were significant differences in mean ADC values between malignant and benign cases (p fibrocystic changes (p fibrocystic changes (40.9% for BI-RADS alone, 64.3% for BI-RADS plus ADC), resulting in a significant improvement in diagnostic accuracy with the addition of ADC. Adding ADC values calculated from DWI (b value = 1500 s/mm(2)) to BI-RADS is a useful way to improve differential diagnostic accuracy for malignant tumors and benign lesions, especially for DCIS versus fibrocystic changes, except in cases of ductal hyperplasia.

Two Capacitive Micro-Machined Ultrasonic Transducers for Wind Speed Measurement.

Science.gov (United States)

Bui, Gia Thinh; Jiang, Yu-Tsung; Pang, Da-Chen

2016-06-02

This paper presents a new wind speed measurement method using a single capacitive micro-machined ultrasonic transducer (CMUT). The CMUT was arranged perpendicular to the direction of the wind flow, and a reflector was set up a short distance away, facing the CMUT. To reduce the size, weight, cost, and power consumption of conventional ultrasonic anemometers this study proposes two CMUT designs for the measurement of wind speed using either the amplitude of the signal or the time of flight (TOF). Each CMUT with a double array element design can transmit and receive signals in five different operation modes. Experiments showed that the two CMUT designs utilizing the TOF were better than those utilizing the amplitude of the signal for wind speed measurements ranging from 1 m/s to 10 m/s, providing a measurement error of less than 0.2 m/s. These results indicate that the sensitivity of the TOF is independent of the five operation modes.

Corporate array of micromachined dipoles on silicon wafer for 60 GHz communication systems

KAUST Repository

Sallam, M. O.

2013-03-01

In this paper, an antenna array operating at 60 GHz and realized on 0.675 mm thick silicon substrate is presented. The array is constructed using four micromachined half-wavelength dipoles fed by a corporate feeding network. Isolation between the antenna array and its feeding network is achieved via a ground plane. This arrangement leads to maximizing the broadside radiation with relatively high front-to-back ratio. Simulations have been carried out using both HFSS and CST, which showed very good agreement. Results reveal that the proposed antenna array has good radiation characteristics, where the directivity, gain, and radiation efficiency are around 10.5 dBi, 9.5 dBi, and 79%, respectively. © 2013 IEEE.

Microfabrication on a curved surface using 3D microlens array projection

International Nuclear Information System (INIS)

Li, Lei; Yi, Allen Y

2009-01-01

Accurate three-dimensional microstructures on silicon or other substrates are becoming increasingly important for optical, electronic, biomedical and medical applications. Traditional microfabrication processes based on cleanroom lithography and dry or wet etching processes are essentially two-dimensional methods. In the past, complicated procedures were designed to create some three-dimensional microstructures; however, these processes were mainly used to create features on planar silicon wafer substrates using the bulk silicon machining technique. In a major departure from previous micromachining processes, a microfabrication process based on microlens projection is presented in this paper. The proposed microfabrication system will have the capabilities of a typical conventional micromachining process plus the unique true three-dimensional replication features based on microlenses that were created on a steep curved substrate. These microlenses were precisely fabricated with a specific pattern on the curved surface that can be used to create microstructures on a pre-defined nonplanar substrate where a layer of photoresist was spin coated. After proper exposure and development, the desired micro patterns are created on the photoresist layer. These micro features can eventually be replicated on the substrate via wet or dry etching processes. The results show that the fabricated three-dimensional microlens array has very high dimensional accuracy and the profile error is less than 6 µm over the entire surface

A Reuse Evaluation for Solar-Cell Silicon Wafers via Shift Revolution and Tool Rotation Using Magnetic Assistance in Ultrasonic Electrochemical Micromachining

Directory of Open Access Journals (Sweden)

P. S. Pa

2013-01-01

Full Text Available A new reuse fabrication using a tool module with rotation and revolution through a process of magnetic assistance in ultrasonic electrochemical micromachining (UEMM for removal of the surface layers from silicon wafers of solar cells is demonstrated. The target of the proposed reuse fabrication method is to replace the current approach, which uses strong acid and grinding and may damage the physical structure of silicon wafers and pollute to the environment. A precisely engineered clean production approach to removal of surface microstructure layers from silicon wafers is to develop a mass production system for recycling defective or discarded silicon wafers of solar cells that can reduce pollution and cost. The high revolution speed of the shift with the high rotation speed of the designed tool increases the discharge mobility and improves the removal effect associated with the high feed rate of the workpiece. High frequency and high power of ultrasonic with large electrolyte flow rate and high magnetic strengths with a small distance between the two magnets provide a large discharge effect and good removal; only a short period of time is required to remove the epoxy film and Si3N4 layer easily and cleanly.

Benzocyclobutene-based electric micromachines supported on microball bearings: Design, fabrication, and characterization

Science.gov (United States)

Modafe, Alireza

This dissertation summarizes the research activities that led to the development of the first microball-bearing-supported linear electrostatic micromotor with benzocyclobutene (BCB) low-k polymer insulating layers. The primary application of this device is long-range, high-speed linear micropositioning. The future generations of this device include rotary electrostatic micromotors and microgenerators. The development of the first generation of microball-bearing-supported micromachines, including device theory, design, and modeling, material characterization, process development, device fabrication, and device test and characterization is presented. The first generation of these devices is based on a 6-phase, bottom-drive, linear, variable-capacitance micromotor (B-LVCM). The design of the electrical and mechanical components of the micromotor, lumped-circuit modeling of the device and electromechanical characteristics, including variable capacitance, force, power, and speed are presented. Electrical characterization of BCB polymers, characterization of BCB chemical mechanical planarization (CMP), development of embedded BCB in silicon (EBiS) process, and integration of device components using microfabrication techniques are also presented. The micromotor consists of a silicon stator, a silicon slider, and four stainless-steel microballs. The aligning force profile of the micromotor was extracted from simulated and measured capacitances of all phases. An average total aligning force of 0.27 mN with a maximum of 0.41 mN, assuming a 100 V peak-to-peak square-wave voltage, was measured. The operation of the micromotor was verified by applying square-wave voltages and characterizing the slider motion. An average slider speed of 7.32 mm/s when excited by a 40 Hz, 120 V square-wave voltage was reached without losing the synchronization. This research has a pivotal impact in the field of power microelectromechanical systems (MEMS). It establishes the foundation for the

Comments on the 'Stress corrosion cracking of zirconium and zircaloy-4 in halide aqueous solutions' by S.B. Farina, G.S. Duffo, J.R. Galvele

International Nuclear Information System (INIS)

Gutman, E.M.

2004-01-01

The above paper [Corros. Sci. 45 (2003) 2497] declares a general approach to describing stress corrosion cracking (SCC) mechanism and despite of the criticism of the so-called 'surface mobility mechanism' (SMM) e.g., [Corros. Sci. 36 (1994) 669, Corros. Sci. 45 (2003) 2105]. The paper [Corros. Sci. 45 (2003) 2497] demonstrates inner contradictions and mutually excluding statements of SMM when fitted calculated and measured values of crack propagation rate. As shown in these Comments, the crack propagation rate calculated using SMM is only the Nabarro-Herring creep deformation rate, which can never be numerically equal to the crack propagation rate. Thus, tests undertaken by the author of SMM cannot be accepted as experimental evidence of the SMM

Smooth transition between SMM and SCM-type slow relaxing dynamics for a 1-D assemblage of {Dy(nitronyl nitroxide)2} units.

Science.gov (United States)

Liu, Ruina; Li, Licun; Wang, Xiaoling; Yang, Peipei; Wang, Chao; Liao, Daizheng; Sutter, Jean-Pascal

2010-04-21

A model example for size effects on the dynamic susceptibility behavior is provided by the chain compound [{Dy(hfac)(3)NitPhIm(2)}Dy(hfac)(3)] (NitPhIm = 2-[4-(1-imidazole)phenyl]nitronyl nitroxide radical). The Arrhenius plot reveals two relaxation regimes attributed to SMM (Delta = 17.1 K and tau(0) = 17.5 x 10(-6) s) and SCM (Delta = 82.7 K and tau(0) = 8.8 x 10(-8) s) behaviors. The ferromagnetic exchange among the spin carriers has been established for the corresponding Gd derivative.

A 16-bit sigma-delta modulator applied in micro-machined inertial sensors

Science.gov (United States)

Honglin, Xu; Qiang, Fu; Hongna, Liu; Liang, Yin; Pengfei, Wang; Xiaowei, Liu

2014-04-01

A fourth-order low-distortion low-pass sigma-delta (ΣΔ) modulator is presented for micro-machined inertial sensors. The proposed single-loop single-bit feedback modulator is optimized with a feed-forward path to decrease the nonlinearities and power consumption. The IC is implemented in a standard 0.6 μm CMOS technology and operates at a sampling frequency of 3.846 MHz. The chip area is 2.12 mm2 with 23 pads. The experimental results indicate a signal-to-noise ratio (SNR) of 100 dB and dynamic range (DR) of 103 dB at an oversampling rate (OSR) of 128 with the input signal amplitude of -3.88 dBFS at 9.8 kHz; the power consumption is 15 mW at a 5 V supply.

A 16-bit sigma–delta modulator applied in micro-machined inertial sensors

International Nuclear Information System (INIS)

Xu Honglin; Fu Qiang; Liu Hongna; Yin Liang; Wang Pengfei; Liu Xiaowei

2014-01-01

A fourth-order low-distortion low-pass sigma–delta (ΣΔ) modulator is presented for micro-machined inertial sensors. The proposed single-loop single-bit feedback modulator is optimized with a feed-forward path to decrease the nonlinearities and power consumption. The IC is implemented in a standard 0.6 μm CMOS technology and operates at a sampling frequency of 3.846 MHz. The chip area is 2.12 mm 2 with 23 pads. The experimental results indicate a signal-to-noise ratio (SNR) of 100 dB and dynamic range (DR) of 103 dB at an oversampling rate (OSR) of 128 with the input signal amplitude of −3.88 dBFS at 9.8 kHz; the power consumption is 15 mW at a 5 V supply. (semiconductor integrated circuits)

Solar wind and coronal structure near sunspot minimum - Pioneer and SMM observations from 1985-1987

Science.gov (United States)

Mihalov, J. D.; Barnes, A.; Hundhausen, A. J.; Smith, E. J.

1990-01-01

Changes in solar wind speed and magnetic polarity observed at the Pioneer spacecraft are discussed here in terms of the changing magnetic geometry implied by SMM coronagraph observations over the period 1985-1987. The pattern of recurrent solar wind streams, the long-term average speed, and the sector polarity of the interplanetary magnetic field all changed in a manner suggesting both a temporal variation, and a changing dependence on heliographic latitude. Coronal observations during this epoch show a systematic variation in coronal structure and the magnetic structure imposed on the expanding solar wind. These observations suggest interpretation of the solar wind speed variations in terms of the familiar model where the speed increases with distance from a nearly flat interplanetary current sheet, and where this current sheet becomes aligned with the solar equatorial plane as sunspot minimum approaches, but deviates rapidly from that orientation after minimum.

Multifrequency Excitation Method for Rapid and Accurate Dynamic Test of Micromachined Gyroscope Chips

Directory of Open Access Journals (Sweden)

Yan Deng

2014-10-01

Full Text Available A novel multifrequency excitation (MFE method is proposed to realize rapid and accurate dynamic testing of micromachined gyroscope chips. Compared with the traditional sweep-frequency excitation (SFE method, the computational time for testing one chip under four modes at a 1-Hz frequency resolution and 600-Hz bandwidth was dramatically reduced from 10 min to 6 s. A multifrequency signal with an equal amplitude and initial linear-phase-difference distribution was generated to ensure test repeatability and accuracy. The current test system based on LabVIEW using the SFE method was modified to use the MFE method without any hardware changes. The experimental results verified that the MFE method can be an ideal solution for large-scale dynamic testing of gyroscope chips and gyroscopes.

Feasibility and its characteristics of CO2 laser micromachining-based PMMA anti-scattering grid estimated by MCNP code simulation.

Science.gov (United States)

Bae, Jun Woo; Kim, Hee Reyoung

2018-01-01

Anti-scattering grid has been used to improve the image quality. However, applying a commonly used linear or parallel grid would cause image distortion, and focusing grid also requires a precise fabrication technology, which is expensive. To investigate and analyze whether using CO2 laser micromachining-based PMMA anti-scattering grid can improve the performance of the grid at a lower cost. Thus, improvement of grid performance would result in improvement of image quality. The cross-sectional shape of CO2 laser machined PMMA is similar to alphabet 'V'. The performance was characterized by contrast improvement factor (CIF) and Bucky. Four types of grid were tested, which include thin parallel, thick parallel, 'V'-type and 'inverse V'-type of grid. For a Bucky factor of 2.1, the CIF of the grid with both the "V" and inverse "V" had a value of 1.53, while the thick and thick parallel types had values of 1.43 and 1.65, respectively. The 'V' shape grid manufacture by CO2 laser micromachining showed higher CIF than parallel one, which had same shielding material channel width. It was thought that the 'V' shape grid would be replacement to the conventional parallel grid if it is hard to fabricate the high-aspect-ratio grid.

Construction of Polynuclear Lanthanide (Ln = Dy(III), Tb(III), and Nd(III)) Cage Complexes Using Pyridine-Pyrazole-Based Ligands: Versatile Molecular Topologies and SMM Behavior.

Science.gov (United States)

Bala, Sukhen; Sen Bishwas, Mousumi; Pramanik, Bhaskar; Khanra, Sumit; Fromm, Katharina M; Poddar, Pankaj; Mondal, Raju

2015-09-08

Employment of two different pyridyl-pyrazolyl-based ligands afforded three octanuclear lanthanide(III) (Ln = Dy, Tb) cage compounds and one hexanuclear neodymium(III) coordination cage, exhibiting versatile molecular architectures including a butterfly core. Relatively less common semirigid pyridyl-pyrazolyl-based asymmetric ligand systems show an interesting trend of forming polynuclear lanthanide cage complexes with different coordination environments around the metal centers. It is noteworthy here that construction of lanthanide complex itself is a challenging task in a ligand system as soft N-donor rich as pyridyl-pyrazol. We report herein some lanthanide complexes using ligand containing only one or two O-donors compare to five N-coordinating sites. The resultant multinuclear lanthanide complexes show interesting magnetic and spectroscopic features originating from different spatial arrangements of the metal ions. Alternating current (ac) susceptibility measurements of the two dysprosium complexes display frequency- and temperature-dependent out-of-phase signals in zero and 0.5 T direct current field, a typical characteristic feature of single-molecule magnet (SMM) behavior, indicating different energy reversal barriers due to different molecular topologies. Another aspect of this work is the occurrence of the not-so-common SMM behavior of the terbium complex, further confirmed by ac susceptibility measurement.

Evaluation of different mathematical models and different b-value ranges of diffusion-weighted imaging in peripheral zone prostate cancer detection using b-value up to 4500 s/mm2.

Directory of Open Access Journals (Sweden)

Zhaoyan Feng

Full Text Available To evaluate the diagnostic performance of different mathematical models and different b-value ranges of diffusion-weighted imaging (DWI in peripheral zone prostate cancer (PZ PCa detection.Fifty-six patients with histologically proven PZ PCa who underwent DWI-magnetic resonance imaging (MRI using 21 b-values (0-4500 s/mm2 were included. The mean signal intensities of the regions of interest (ROIs placed in benign PZs and cancerous tissues on DWI images were fitted using mono-exponential, bi-exponential, stretched-exponential, and kurtosis models. The b-values were divided into four ranges: 0-1000, 0-2000, 0-3200, and 0-4500 s/mm2, grouped as A, B, C, and D, respectively. ADC, , D*, f, DDC, α, Dapp, and Kapp were estimated for each group. The adjusted coefficient of determination (R2 was calculated to measure goodness-of-fit. Receiver operating characteristic curve analysis was performed to evaluate the diagnostic performance of the parameters.All parameters except D* showed significant differences between cancerous tissues and benign PZs in each group. The area under the curve values (AUCs of ADC were comparable in groups C and D (p = 0.980 and were significantly higher than those in groups A and B (p< 0.05 for all. The AUCs of ADC and Kapp in groups B and C were similar (p = 0.07 and p = 0.954, and were significantly higher than the other parameters (p< 0.001 for all. The AUCs of ADC in group D was slightly higher than Kapp (p = 0.002, and both were significantly higher than the other parameters (p< 0.001 for all.ADC derived from conventional mono-exponential high b-value (3200 s/mm2 models is an optimal parameter for PZ PCa detection.

A sub-cm micromachined electron microscope

Science.gov (United States)

Feinerman, A. D.; Crewe, D. A.; Perng, D. C.; Shoaf, S. E.; Crewe, A. V.

1993-01-01

A new approach for fabricating macroscopic (approximately 10x10x10 mm(exp 3)) structures with micron accuracy has been developed. This approach combines the precision of semiconductor processing and fiber optic technologies. A (100) silicon wafer is anisotropically etched to create four orthogonal v-grooves and an aperture on each 10x12 mm die. Precision 308 micron optical fibers are sandwiched between the die to align the v-grooves. The fiber is then anodically bonded to the die above and below it. This procedure is repeated to create thick structures and a stack of 5 or 6 die will be used to create a miniature scanning electron microscope (MSEM). Two die in the structure will have a segmented electrode to deflect the beam and correct for astigmatism. The entire structure is UHV compatible. The performance of an SEM improves as its length is reduced and a sub-cm 2 keV MSEM with a field emission source should have approximately 1 nm resolution. A low voltage high resolution MSEM would be useful for the examination of biological specimens and semiconductors with a minimum of damage. The first MSEM will be tested with existing 6 micron thermionic sources. In the future a micromachined field emission source will be used. The stacking technology presented in this paper can produce an array of MSEMs 1 to 30 mm in length with a 1 mm or larger period. A key question being addressed by this research is the optimum size for a low voltage MSEM which will be determined by the required spatial resolution, field of view, and working distance.

Predictable self-assembled [2×2] Ln(III)4 square grids (Ln = Dy,Tb)-SMM behaviour in a new lanthanide cluster motif.

Science.gov (United States)

Anwar, Muhammad Usman; Thompson, Laurence Kenneth; Dawe, Louise Nicole; Habib, Fatemah; Murugesu, Muralee

2012-05-14

The ditopic carbohydrazone ligand (L1) produces the square, self-assembled [2×2] grids [Dy(4)(L1)(4)(OH)(4)]Cl(2) (1) and [Ln(4)(L1)(4)(μ(4)-O)(μ(2)-1,1-N(3))(4)] (Ln = Dy (2), Tb (3)), with 2 exhibiting SMM behaviour. Two relaxation processes occur with U(eff) = 51 K, 91 K in the absence of an external field, and one with U(eff) = 270 K in the presence of a 1600 Oe optimum field. This journal is © The Royal Society of Chemistry 2012

The GBT Discovery of a Massive CO(1-0) Filament Associated with the z=2.8 Submillimeter Galaxy SMM J02399-0136

Science.gov (United States)

Frayer, David; Maddalena, Ronald; Vanden Bout, Paul; Watts, Galen

2018-01-01

Using the Ka-band receiver on the GBT, we have uncovered a new velocity component in CO(1-0) associated the submillimeter galaxy SMM J02399-0136. Follow-up imaging with ALMA in CO(3-2) shows that this velocity component is associated with a large linear filament covering 8" on the sky (60 kpc). This component comprises 50% or more of the total molecular gas mass in the system, and may repesent tidal debris from a merger event or represents inflowing cold molecular gas that is fueling the ongoing starburst and AGN activity.

A Three-Dimensional Enormous Surface Area Aluminum Microneedle Array with Nanoporous Structure

Directory of Open Access Journals (Sweden)

Po Chun Chen

2013-01-01

Full Text Available We proposed fabricating an aluminum microneedle array with a nanochannel structure on the surface by combining micromachining, electrolyte polishing, and anodization methods. The microneedle array provides a three-dimensional (3D structure that possesses several hundred times more surface area than a traditional nanochannel template. Therefore, the microneedle array can potentially be used in many technology applications. This 3D microneedle array device can not only be used for painless injection or extraction, but also for storage, highly sensitive detection, drug delivery, and microelectrodes. From the calculation we made, the microneedle array not only increases surface area, but also enlarges the capacity of the device. Therefore, the microneedle array can further be used on many detecting, storing, or drug delivering applications.

GaAs micromachining in the 1 H2SO4:1 H2O2:8 H2O system. From anisotropy to simulation

Science.gov (United States)

Tellier, C. R.

2011-02-01

The bulk micromachining on (010), (110) and (111)A GaAs substrates in the 1 H2SO4:1 H2O2:8 H2O system is investigated. Focus is placed on anisotropy of 3D etching shapes with a special emphasis on convex and concave undercuts which are of prime importance in the wet micromachining of mechanical structures. Etched structures exhibit curved contours and more and less rounded sidewalls showing that the anisotropy is of type 2. This anisotropy can be conveniently described by a kinematic and tensorial model. Hence, a database composed of dissolution constants is further determined from experiments. A self-elaborated simulator which works with the proposed database is used to derive theoretical 3D shapes. Simulated shapes agree well with observed shapes of microstructures. The successful simulations open up two important applications for MEMS: CAD of mask patterns and meshing of simulated shapes for FEM simulation tools.

Micromachined silicon acoustic delay line with improved structural stability and acoustic directivity for real-time photoacoustic tomography

Science.gov (United States)

Cho, Young; Kumar, Akhil; Xu, Song; Zou, Jun

2017-03-01

Recent studies have shown that micromachined silicon acoustic delay lines can provide a promising solution to achieve real-time photoacoustic tomography without the need for complex transducer arrays and data acquisition electronics. However, as its length increases to provide longer delay time, the delay line becomes more vulnerable to structural instability due to reduced mechanical stiffness. In addition, the small cross-section area of the delay line results in a large acoustic acceptance angle and therefore poor directivity. To address these two issues, this paper reports the design, fabrication, and testing of a new silicon acoustic delay line enhanced with 3D printed polymer micro linker structures. First, mechanical deformation of the silicon acoustic delay line (with and without linker structures) under gravity was simulated by using finite element method. Second, the acoustic crosstalk and acoustic attenuation caused by the polymer micro linker structures were evaluated with both numerical simulation and ultrasound transmission testing. The result shows that the use of the polymer micro linker structures significantly improves the structural stability of the silicon acoustic delay lines without creating additional acoustic attenuation and crosstalk. In addition, a new tapered design for the input terminal of the delay line was also investigate to improve its acoustic directivity by reducing the acoustic acceptance angle. These two improvements are expected to provide an effective solution to eliminate current limitations on the achievable acoustic delay time and out-of-plane imaging resolution of micromachined silicon acoustic delay line arrays.

From a Dy(III) single molecule magnet (SMM) to a ferromagnetic [Mn(II)Dy(III)Mn(II)] trinuclear complex.

Science.gov (United States)

Bhunia, Asamanjoy; Gamer, Michael T; Ungur, Liviu; Chibotaru, Liviu F; Powell, Annie K; Lan, Yanhua; Roesky, Peter W; Menges, Fabian; Riehn, Christoph; Niedner-Schatteburg, Gereon

2012-09-17

The Schiff base compound 2,2'-{[(2-aminoethyl)imino]bis[2,1-ethanediyl-nitriloethylidyne]}bis-2-hydroxy-benzoic acid (H(4)L) as a proligand was prepared in situ. This proligand has three potential coordination pockets which make it possible to accommodate from one to three metal ions allowing for the possible formation of mono-, di-, and trinuclear complexes. Reaction of in situ prepared H(4)L with Dy(NO(3))(3)·5H(2)O resulted in the formation of a mononuclear complex [Dy(H(3)L)(2)](NO(3))·(EtOH)·8(H(2)O) (1), which shows SMM behavior. In contrast, reaction of in situ prepared H(4)L with Mn(ClO(4))(2)·6H(2)O and Dy(NO(3))(3)·5H(2)O in the presence of a base resulted in a trinuclear mixed 3d-4f complex (NHEt(3))(2)[Dy{Mn(L)}(2)](ClO(4))·2(H(2)O) (2). At low temperatures, compound 2 is a weak ferromagnet. Thus, the SMM behavior of compound 1 can be switched off by incorporating two Mn(II) ions in close proximity either side of the Dy(III). This quenching behavior is ascribed to the presence of the weak ferromagnetic interactions between the Mn(II) and Dy(III) ions, which at T > 2 K act as a fluctuating field causing the reversal of magnetization on the dysprosium ion. Mass spectrometric ion signals related to compounds 1 and 2 were both detected in positive and negative ion modes via electrospray ionization mass spectrometry. Hydrogen/deuterium exchange (HDX) reactions with ND(3) were performed in a FT-ICR Penning-trap mass spectrometer.

A micromachined membrane-based active probe for biomolecular mechanics measurement

Science.gov (United States)

Torun, H.; Sutanto, J.; Sarangapani, K. K.; Joseph, P.; Degertekin, F. L.; Zhu, C.

2007-04-01

A novel micromachined, membrane-based probe has been developed and fabricated as assays to enable parallel measurements. Each probe in the array can be individually actuated, and the membrane displacement can be measured with high resolution using an integrated diffraction-based optical interferometer. To illustrate its application in single-molecule mechanics experiments, this membrane probe was used to measure unbinding forces between L-selectin reconstituted in a polymer-cushioned lipid bilayer on the probe membrane and an antibody adsorbed on an atomic force microscope cantilever. Piconewton range forces between single pairs of interacting molecules were measured from the cantilever bending while using the membrane probe as an actuator. The integrated diffraction-based optical interferometer of the probe was demonstrated to have floor for frequencies as low as 3 Hz with a differential readout scheme. With soft probe membranes, this low noise level would be suitable for direct force measurements without the need for a cantilever. Furthermore, the probe membranes were shown to have 0.5 µm actuation range with a flat response up to 100 kHz, enabling measurements at fast speeds.

Activity associated with coronal mass ejections at solar minimum - SMM observations from 1984-1986

Science.gov (United States)

St. Cyr, O. C.; Webb, D. F.

1991-01-01

Seventy-three coronal mass ejections (CMEs) observed by the coronagraph aboard SMM between 1984 and 1986 were examined in order to determine the distribution of various forms of solar activity that were spatially and temporally associated with mass ejections during solar minimum phase. For each coronal mass ejection a speed was measured, and the departure time of the transient from the lower corona estimated. Other forms of solar activity that appeared within 45 deg longitude and 30 deg latitude of the mass ejection and within +/-90 min of its extrapolated departure time were explored. The statistical results of the analysis of these 73 CMEs are presented, and it is found that slightly less than half of them were infrequently associated with other forms of solar activity. It is suggested that the distribution of the various forms of activity related to CMEs does not change at different phases of the solar cycle. For those CMEs with associations, it is found that eruptive prominences and soft X-rays were the most likely forms of activity to accompany the appearance of mass ejections.

Simultaneous SMM flat crystal spectrometer and Very Large Array observations of solar active regions

Science.gov (United States)

Lang, Kenneth R.; Willson, Robert F.; Smith, Kermit L.; Strong, Keith T.

1987-01-01

High-resolution images of the quiescent emission from two solar active regions at 20 cm (VLA) and soft X-ray (SMM FCS) wavelengths are compared. There are regions where the X-ray coronal loops have been completely imaged at 20 cm wavelength. In other regions, the X-ray radiation was detected without detectable 20 cm radiation, and vice versa. The X-ray data were used to infer average electron temperatures of about 3-million K and average electron densities of about 2.5 x 10 to the 9th/cu cm for the X-ray emitting plasma in the two active regions. The thermal bremsstrahlung of the X-ray emitting plasma is optically thin at 20 cm wavelength. The 20 cm brightness temperatures were always less than T(e), which is consistent with optically thin bremsstrahlung. The low T(B) can be explained if a higher, cooler plasma covers the hotter X-ray emitting plasma. Thermal gyroresonance radiation must account for the intense 20 cm radiation near and above sunspots where no X-ray radiation is detected.

Giant flexoelectric polarization in a micromachined ferroelectric diaphragm

KAUST Repository

Wang, Zhihong

2012-08-14

The coupling between dielectric polarization and strain gradient, known as flexoelectricity, becomes significantly large on the micro- and nanoscale. Here, it is shown that giant flexoelectric polarization can reverse remnant ferroelectric polarization in a bent Pb(Zr0.52Ti0.48) O3 (PZT) diaphragm fabricated by micromachining. The polarization induced by the strain gradient and the switching behaviors of the polarization in response to an external electric field are investigated by observing the electromechanical coupling of the diaphragm. The method allows determination of the absolute zero polarization state in a PZT film, which is impossible using other existing methods. Based on the observation of the absolute zero polarization state and the assumption that bending of the diaphragm is the only source of the self-polarization, the upper bound of flexoelectric coefficient of PZT film is calculated to be as large as 2.0 × 10-4 C m -1. The strain gradient induced by bending the diaphragm is measured to be on the order of 102 m-1, three orders of magnitude larger than that obtained in the bulk material. Because of this large strain gradient, the estimated giant flexoelectric polarization in the bent diaphragm is on the same order of magnitude as the normal remnant ferroelectric polarization of PZT film. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Receive-Noise Analysis of Capacitive Micromachined Ultrasonic Transducers.

Science.gov (United States)

Bozkurt, Ayhan; Yaralioglu, G Goksenin

2016-11-01

This paper presents an analysis of thermal (Johnson) noise received from the radiation medium by otherwise noiseless capacitive micromachined ultrasonic transducer (CMUT) membranes operating in their fundamental resonance mode. Determination of thermal noise received by multiple numbers of transducers or a transducer array requires the assessment of cross-coupling through the radiation medium, as well as the self-radiation impedance of the individual transducer. We show that the total thermal noise received by the cells of a CMUT has insignificant correlation, and is independent of the radiation impedance, but is only determined by the mass of each membrane and the electromechanical transformer ratio. The proof is based on the analytical derivations for a simple transducer with two cells, and extended to transducers with numerous cells using circuit simulators. We used a first-order model, which incorporates the fundamental resonance of the CMUT. Noise power is calculated by integrating over the entire spectrum; hence, the presented figures are an upper bound for the noise. The presented analyses are valid for a transimpedance amplifier in the receive path. We use the analysis results to calculate the minimum detectable pressure of a CMUT. We also provide an analysis based on the experimental data to show that output noise power is limited by and comparable to the theoretical upper limit.

Enhancing structural integrity of adhesive bonds through pulsed laser surface micro-machining

KAUST Repository

Diaz, Edwin Hernandez

2015-01-01

of different kinds of heterogeneous surface properties that may replicate this behavior and the mechanisms at work. In order to do this, we used pulsed laser ablation on copper substrates (CuZn40) aiming to increase adhesion for bonding. A Yb-fiber laser

Monolithic integration of micromachined sensors and CMOS circuits based on SOI technologies

International Nuclear Information System (INIS)

Yu Xiaomei; Tang Yaquan; Zhang Haitao

2008-01-01

This note presents a novel way to monolithically integrate micro-cantilever sensors and signal conditioning circuits by combining SOI CMOS and SOI micromachining technologies. In order to improve the sensor performance and reduce the system volume, an integrated sensor system composed of a piezoresistive cantilever array, a temperature-compensation current reference, a digitally controlled multiplexer and an instrument amplifier is designed and finally fabricated. A post-SOI CMOS process is developed to realize the integrated sensor system which is based on a standard CMOS process with one more mask to define the cantilever structure at the end of the process. Measurements on the finished SOI CMOS devices and circuits show that the integration process has good compatibility both for the cantilever sensors and for the CMOS circuits, and the SOI CMOS integration process can decrease about 25% sequences compared with the bulk silicon CMOS process. (note)

Modeling and Design of Capacitive Micromachined Ultrasonic Transducers Based-on Database Optimization

International Nuclear Information System (INIS)

Chang, M W; Gwo, T J; Deng, T M; Chang, H C

2006-01-01

A Capacitive Micromachined Ultrasonic Transducers simulation database, based on electromechanical coupling theory, has been fully developed for versatile capacitive microtransducer design and analysis. Both arithmetic and graphic configurations are used to find optimal parameters based on serial coupling simulations. The key modeling parameters identified can improve microtransducer's character and reliability effectively. This method could be used to reduce design time and fabrication cost, eliminating trial-and-error procedures. Various microtransducers, with optimized characteristics, can be developed economically using the developed database. A simulation to design an ultrasonic microtransducer is completed as an executed example. The dependent relationship between membrane geometry, vibration displacement and output response is demonstrated. The electromechanical coupling effects, mechanical impedance and frequency response are also taken into consideration for optimal microstructures. The microdevice parameters with the best output signal response are predicted, and microfabrication processing constraints and realities are also taken into consideration

Stability and spring constant investigation for micromachined inductive suspensions: theoretical analysis vs. experimental results

International Nuclear Information System (INIS)

Poletkin, K; Lu, Z; Wallrabe, U; Badilita, V; Den Hartogh, B

2014-01-01

We present a linear analytical model coupled with experimental analysis to discuss stability of a levitated proof mass (PM) in a micromachined inductive suspension (MIS), which has been previously introduced and characterized. The model is a function of the MIS geometry, describes the dynamics of a levitated disk-shaped PM near the equilibrium point, and predicts conditions for stable levitation. The experimental setup directly measures the lateral component of the Lorentz force, which has a stabilization role in the MIS structure, as well as the vertical levitation force. The experimental setup is further used to derive mechanical parameters such as stiffness values relative to lateral, vertical and angular displacements, proven to be in excellent agreement with the values predicted by the analytical model

A Three-Dimensional Enormous Surface Area Aluminum Microneedle Array with Nanoporous Structure

International Nuclear Information System (INIS)

Chen, P.Ch.; Zou, J.; Hsieh, Sh.J.; Chen, Ch.Ch.

2013-01-01

We proposed fabricating an aluminum micro needle array with a nano channel structure on the surface by combining micromachining, electrolyte polishing, and anodization methods. The micro needle array provides a three-dimensional (3D) structure that possesses several hundred times more surface area than a traditional nano channel template. Therefore, the micro needle array can potentially be used in many technology applications. This 3D micro needle array device can not only be used for painless injection or extraction, but also for storage, highly sensitive detection, drug delivery, and microelectrodes. From the calculation we made, the micro needle array not only increases surface area, but also enlarges the capacity of the device. Therefore, the micro needle array can further be used on many detecting, storing, or drug delivering applications.

Removal behaviors of sulfamonomethoxine and its degradation intermediates in fresh aquaculture wastewater using zeolite/TiO2 composites.

Science.gov (United States)

Nomura, Youhei; Fukahori, Shuji; Fukada, Haruhisa; Fujiwara, Taku

2017-10-15

Removal efficiencies of sulfamonomethoxine (SMM) and its degradation intermediates formed by treatment with zeolite/TiO 2 composites through adsorption and photocatalysis were investigated in fresh aquaculture wastewater (FAWW). Coexistent substances in the FAWW showed no inhibitory effects against SMM adsorption. Although coexistent substances in the FAWW inhibited the photocatalytic decomposition of SMM, the composites mitigated the inhibition, possibly because of concentration of SMM on their surface by adsorption. LC/MS/MS analyses revealed that hydroxylation of amino phenyl and pyrimidinyl portions, transformation of the amino group in the amino phenyl portion into a nitroso group, and substitution of the methoxy group with a hydroxyl group occurring in the initial reaction resulted in the formation of various intermediates during the photocatalysis of SMM. All detected intermediates had a ring structure, and almost all intermediates disappeared at the same time SMM was completely decomposed. Ph-OH formed by hydroxylation of the phenyl portion was detected upon decomposition of SMM during photocatalysis. The removal of Ph-OH by the composites proceeded more rapidly than that by TiO 2 alone under ultraviolet irradiation. The SMM and Ph-OH were completely degraded by the composites within 30min, showing that the zeolite/TiO 2 composites were effective in removing SMM and its intermediates from FAWW. Copyright © 2017 Elsevier B.V. All rights reserved.

Micromachined silicon cantilevers with integrated high-frequency magnetoimpedance sensors for simultaneous strain and magnetic field detection

Science.gov (United States)

Buettel, G.; Joppich, J.; Hartmann, U.

2017-12-01

Giant magnetoimpedance (GMI) measurements in the high-frequency regime utilizing a coplanar waveguide with an integrated Permalloy multilayer and micromachined on a silicon cantilever are reported. The fabrication process is described in detail. The aspect ratio of the magnetic multilayer in the magnetoresistive and magnetostrictive device was varied. Tensile strain and compressive strain were applied. Vector network analyzer measurements in the range from the skin effect to ferromagnetic resonance confirm the technological potential of GMI-based micro-electro-mechanical devices for strain and magnetic field sensing applications. The strain-impedance gauge factor was quantified by finite element strain calculations and reaches a maximum value of almost 200.

Chronic behavior evaluation of a micro-machined neural implant with optimized design based on an experimentally derived model.

Science.gov (United States)

Andrei, Alexandru; Welkenhuysen, Marleen; Ameye, Lieveke; Nuttin, Bart; Eberle, Wolfgang

2011-01-01

Understanding the mechanical interactions between implants and the surrounding tissue is known to have an important role for improving the bio-compatibility of such devices. Using a recently developed model, a particular micro-machined neural implant design aiming the reduction of insertion forces dependence on the insertion speed was optimized. Implantations with 10 and 100 μm/s insertion speeds showed excellent agreement with the predicted behavior. Lesion size, gliosis (GFAP), inflammation (ED1) and neuronal cells density (NeuN) was evaluated after 6 week of chronic implantation showing no insertion speed dependence.

A Micromachined Infrared Senor for an Infrared Focal Plane Array

Directory of Open Access Journals (Sweden)

Seong M. Cho

2008-04-01

Full Text Available A micromachined infrared sensor for an infrared focal plane array has been designed and fabricated. Amorphous silicon was used as a sensing material, and silicon nitride was used as a membrane material. To get a good absorption in infrared range, the sensor structure was designed as a l/4 cavity structure. A Ni-Cr film was selected as an electrode material and mixed etching scheme was applied in the patterning process of the Ni-Cr electrode. All the processes were made in 0.5 μm iMEMS fabricated in the Electronics and Telecommunication Research Institute (ETRI. The processed MEMS sensor had a small membrane deflection less than 0.15 μm. This small deflection can be attributed to the rigorous balancing of the stresses of individual layers. The efficiency of infrared absorption was more than 75% in the wavelength range of 8 ~ 14 μm. The processed infrared sensor showed high responsivity of ~230 kV/W at 1.0V bias and 2 Hz operation condition. The time constant of the sensor was 8.6 msec, which means that the sensor is suitable to be operated in 30 Hz frame rate.

Bending-induced electromechanical coupling and large piezoelectric response in a micromachined diaphragm

KAUST Repository

Wang, Zhihong

2013-11-04

We investigated the dependence of electromechanical coupling and the piezoelectric response of a micromachined Pb(Zr 0.52 Ti 0.48)O 3 (PZT) diaphragm on its curvature by observing the impedance spectrum and central deflection responses to a small AC voltage. The curvature of the diaphragm was controlled by applying air pressure to its back. We found that a depolarized flat diaphragm does not initially exhibit electromechanical coupling or the piezoelectric response. However, upon the application of static air pressure to the diaphragm, both electromechanical coupling and the piezoelectric response can be induced in the originally depolarized diaphragm. The piezoelectric response increases as the curvature increases and a giant piezoelectric response can be obtained from a bent diaphragm. The obtained results clearly demonstrate that a high strain gradient in a diaphragm can polarize a PZT film through a flexoelectric effect, and that the induced piezoelectric response of the diaphragm can be controlled by adjusting its curvature.

Achievement report for fiscal 1996 on the research and development of micromachine technology. Development of microfactory technology; 1996 nendo micromachine gijutsu no kenkyu kaihatsu seika hokokusho. Microfactory gijutsu kaihatsu

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

The goal is to save energy and minimize the working space by constructing a manufacturing system comprising various micromachines with their dimensions fit for parts and products they handle. Development continues relative to microprocessing (electrolysis, and optical processing) and microscopic liquid operation (micropump, and part holding device). Under research in relation to the assembly process are a micro-arm to handle tiny parts and precision techniques for interfitting within a very small microfactory, a piezoelectric actuator for microscopic position adjusting, and ultraprecise microprocessing techniques indispensable for their manufacture. Also under research are the incorporation of optically driven microdevices developed before the preceding fiscal year into a microfactory and the study of microservo actuators capable of sophisticated positioning and velocity control. Concerning the microscopic transport system to deal with microscopic parts and products, studies are under way so as to embody systems driven by actuators of the electromagnetic type and electrostatic type. In this paper, reference is made to inspection techniques and comprehensive investigations. (NEDO)

Advances on the nanostructuration of magnetic molecules on surfaces: the case of single-molecule magnets (SMM).

Science.gov (United States)

Gómez-Segura, Jordi; Veciana, Jaume; Ruiz-Molina, Daniel

2007-09-28

SMMs exhibit slow magnetization relaxation rates characteristic of nanodomain particles whose origin is however on individual molecules. For this reason, they have attracted much interest due to their potential applications in high-density information storage devices and quantum computing applications, where for instance, each molecule can be used as a magnetic bit of information. However, for this to become a reality, several basic studies such as their deposition on surfaces are still highly required. Here we will revise all the experimental approximations that have been so far reported for their addressing, nanostructuration and study on surfaces, from the use of stamps as templates to their anchorage to gold surface through the use of thiol-based ligands. It is also important to emphasize that the results and methodologies described along this review are applicable not only to SMMs but to any molecular material.

MEMS: A new approach to micro-optics

Energy Technology Data Exchange (ETDEWEB)

Sniegowski, J.J.

1997-12-31

MicroElectroMechanical Systems (MEMS) and their fabrication technologies provide great opportunities for application to micro-optical systems (MOEMS). Implementing MOEMS technology ranges from simple, passive components to complicated, active systems. Here, an overview of polysilicon surface micromachining MEMS combined with optics is presented. Recent advancements to the technology, which may enhance its appeal for micro-optics applications are emphasized. Of all the MEMS fabrication technologies, polysilicon surface micromachining technology has the greatest basis in and leverages the most the infrastructure for silicon integrated circuit fabrication. In that respect, it provides the potential for very large volume, inexpensive production of MOEMS. This paper highlights polysilicon surface micromachining technology in regards to its capability to provide both passive and active mechanical elements with quality optical elements.

A top-crossover-to-bottom addressed segmented annular array using piezoelectric micromachined ultrasonic transducers

Science.gov (United States)

Jung, Joontaek; Lee, Wonjun; Kang, Woojin; Hong, Hyeryung; Yuen Song, Hi; Oh, Inn-yeal; Park, Chul Soon; Choi, Hongsoo

2015-11-01

We design and fabricate segmented annular arrays (SAAs) using piezoelectric micromachined ultrasonic transducers (pMUTs) to demonstrate the feasibility of acoustic focusing of ultrasound. The fabricated SAAs have 25 concentric top-electrode signal lines and eight bottom-electrodes for grounding to enable electronic steering of selectively grouped ultrasonic transducers from 2393 pMUT elements. Each element in the array is connected by top-crossover-to-bottom metal bridges, which reduce the parasitic capacitance. Circular-shaped pMUT elements, 120 μm in diameter, are fabricated using 1 μm-thick sol-gel lead zirconate titanate on a silicon wafer. To utilize the high-density pMUT array, a deep reactive ion etching process is used for anisotropic silicon etching to realize the transducer membranes. The resonant frequency and effective coupling coefficient of the elements, measured with an impedance analyzer, yields 1.517 MHz and 1.29%, respectively, in air. The SAAs using pMUTs are packaged on a printed circuit board and coated with parylene C for acoustic intensity measurements in water. The ultrasound generated by each segmented array is focused on a selected point in space. When a 5 Vpp, 1.5 MHz square wave is applied, the maximum spatial peak temporal average intensity ({{I}\\text{spta}} ) is found to be 79 mW cm-2 5 mm from the SAAs’ surface without beamforming. The beam widths (-3 dB) of ultrasonic radiation patterns in the elevation and azimuth directions are recorded as 3 and 3.4 mm, respectively. The results successfully show the feasibility of focusing ultrasound on a small area with SAAs using pMUTs.

3D Printing, Ink Casting and Micromachined Lamination (3D PICLμM): A Makerspace Approach to the Fabrication of Biological Microdevices

OpenAIRE

Avra Kundu; Tariq Ausaf; Swaminathan Rajaraman

2018-01-01

We present a novel benchtop-based microfabrication technology: 3D printing, ink casting, micromachined lamination (3D PICLμM) for rapid prototyping of lab-on-a-chip (LOC) and biological devices. The technology uses cost-effective, makerspace-type microfabrication processes, all of which are ideally suited for low resource settings, and utilizing a combination of these processes, we have demonstrated the following devices: (i) 2D microelectrode array (MEA) targeted at in vitro neural and cardi...

Review of piezoelectric micromachined ultrasonic transducers and their applications

International Nuclear Information System (INIS)

Jung, Joontaek; Lee, Wonjun; Kang, Woojin; Shin, Eunjung; Choi, Hongsoo; Ryu, Jungho

2017-01-01

In recent decades, micromachined ultrasonic transducers (MUTs) have been investigated as an alternative to conventional piezocomposite ultrasonic transducers, primarily due to the advantages that microelectromechanical systems provide. Miniaturized ultrasonic systems require ultrasonic transducers integrated with complementary metal-oxide-semiconductor circuits. Hence, piezoelectric MUTs (pMUTs) and capacitive MUTs (cMUTs) have been developed as the most favorable solutions. This paper reviews the basic equations to understand the characteristics of thin-film-based piezoelectric devices and presents recent research on pMUTs, including current approaches and limitations. Methods to improve the coupling coefficient of pMUTs are also investigated, such as device structure, materials, and fabrication techniques. The device structure improvements include multielectrode pMUTs, partially clamped boundary conditions, and 3D pMUTs (curved and domed types), where the latter can provide an electromechanical coupling coefficient of up to 45%. The piezoelectric coefficient ( e 31 ) can be increased by controlling the crystal texture (seed layer of γ -Al 2 O 3 ), using single-crystal (PMN-PT) materials, or control of residual stresses (using SiO 2 layer). Arrays of pMUTs can be implemented for various applications including intravascular ultrasound, fingerprint sensors, rangefinders in air, and wireless power supply systems. pMUTs are expected to be an ideal solution for applications such as mobile biometric security (fingerprint sensors) and rangefinders due to their superior power efficiency and compact size. (topical review)

Review of piezoelectric micromachined ultrasonic transducers and their applications

Science.gov (United States)

Jung, Joontaek; Lee, Wonjun; Kang, Woojin; Shin, Eunjung; Ryu, Jungho; Choi, Hongsoo

2017-11-01

In recent decades, micromachined ultrasonic transducers (MUTs) have been investigated as an alternative to conventional piezocomposite ultrasonic transducers, primarily due to the advantages that microelectromechanical systems provide. Miniaturized ultrasonic systems require ultrasonic transducers integrated with complementary metal-oxide-semiconductor circuits. Hence, piezoelectric MUTs (pMUTs) and capacitive MUTs (cMUTs) have been developed as the most favorable solutions. This paper reviews the basic equations to understand the characteristics of thin-film-based piezoelectric devices and presents recent research on pMUTs, including current approaches and limitations. Methods to improve the coupling coefficient of pMUTs are also investigated, such as device structure, materials, and fabrication techniques. The device structure improvements include multielectrode pMUTs, partially clamped boundary conditions, and 3D pMUTs (curved and domed types), where the latter can provide an electromechanical coupling coefficient of up to 45%. The piezoelectric coefficient (e 31) can be increased by controlling the crystal texture (seed layer of γ-Al2O3), using single-crystal (PMN-PT) materials, or control of residual stresses (using SiO2 layer). Arrays of pMUTs can be implemented for various applications including intravascular ultrasound, fingerprint sensors, rangefinders in air, and wireless power supply systems. pMUTs are expected to be an ideal solution for applications such as mobile biometric security (fingerprint sensors) and rangefinders due to their superior power efficiency and compact size.

Multi-wave band SMM-VLA observations of an M2 flare and an associated coronal mass ejection

Science.gov (United States)

Willson, Robert F.; Lang, Kenneth R.; Schmelz, Joan T.; Gonzalez, Raymond D.; Smith, Kermit L.

1991-01-01

Results are presented of observations of an M2 flare and an associated coronal mass ejection CME by instruments on the SMM as well as by the VLA and other ground-based observatories on September 30, 1988. The multiwave band data show a gradual slowly changing event which lasted several hours. The microwave burst emission was found to originate in compact moderately circularly polarized sources located near the sites of bright H-alpha and soft X-ray emission. These data are combined with estimates of an electron temperature of 1.5 x 10 to the 7th K and an emission measure of about 2.0 x 10 to the 49th/cu cm obtained from Ca XIX and Fe XXV spectra to show that the microwave emission can be attributed to thermal gyrosynchrotron radiation in regions where the magnetic field strength is 425-650 G. The CME acceleration at low altitudes is measured on the basis of ground- and space-based coronagraphs.

Development of micro capacitive accelerometer for subsurface microseismic measurement; Micromachining ni yoru chika danseiha kenshutsu no tame no silicon yoryogata kasokudo sensor no seisaku

Energy Technology Data Exchange (ETDEWEB)

Nishizawa, M; Niitsuma, H; Esashi, M [Tohoku University, Sendai (Japan). Faculty of Engineering

1997-05-27

A silicon capacitive accelerometer was fabricated to detect subsurface elastic waves by using micromachining technology. Characteristics required for it call for capability of detecting acceleration with amplitudes from 0.1 to 1 gal and flat amplitude characteristics in frequency bands of 10 Hz to several kHz. For the purpose of measuring transition phenomena, linear phase characteristics in the required bands must be guaranteed, cross sensitivity must be small, and resistance to water, pressure and heat is demanded. Sensitivity of the sensor is determined finally by noise level in a detection circuit. The sensor`s minimum detection capability was 40 mgal in the case of the distance between a weight and an electrode being 3 {mu}m. This specification value is a value realizable by the current micromachining technology. Dimensions for the weight and other members were decided with the natural frequency to make band width 2 kHz set to 4 kHz. Completion of the product has not been achieved yet, however, because of a problem that the weight gets stuck on the electrode plate in anode bonding in the assembly process. 7 refs., 5 figs., 1 tab.

Survey of practical application fields of micro-machine and micro-factory technologies in Japan; Nippon ni okeru maikuro machine oyobi maikuro factory gijutsu no jitsuyoka bun`ya chosa

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-02-01

As for micro-machine and micro-factory technologies, research and development trends promoted by private companies were surveyed except for national projects. In the field of main technology development by private companies which do not participate in national projects, developments of micro-devices, such as micro-sensor, and micro-actuator, as well as basic technologies, such as machining, assembly, and material technology, are predominant. The applied fields of these aim at electronic industries for measurement and analysis equipment, motorcar sensors, information, communication, and home electric products. While, there are a few research and developments as to micro-robots. Research and developments aiming at application to medical field are widely promoted by private companies. In this field, micro-machining technology for micro-surgery and endoscopes is prospective. There is a photo-forceps technology for handling the micro-parts. However, there are few researches considering the micro-factory. 146 refs., 73 figs., 7 tabs.

A heptadecanuclear Mn(III)9Dy(III)8 cluster derived from triethanolamine with two edge sharing supertetrahedra as the core and displaying SMM behaviour.

Science.gov (United States)

Langley, Stuart K; Moubarakia, Boujemaa; Murray, Keith S

2010-06-07

A heterometallic, heptadecanuclear cluster of formula [Mn(III)9Dy(III)8O8(OH)8(tea)2(teaH)2(teaH2)4(Ac)4(NO3)2(H2O)4](NO3)7·8H2O (1) is reported. The core of 1 displays two edge sharing Mn(III)5Dy(III)5 supertetrahedra and represents one of the largest Mn/4f cluster compound so far reported. Magnetic studies show that 1 displays probable SMM behaviour as observed via non-zero values in the χM''vs T plot.

Double-section curvature tunable functional actuator with micromachined buckle and grid wire for electricity delivery

Science.gov (United States)

Feng, Guo-Hua; Hou, Sheng-You

2015-09-01

This paper presents an ionic polymer metal composite (IPMC)-driven tentacle-like biocompatible flexible actuator with double-section curvature tunability. This actuator, possessing an embedded electrical transmission ability that mimics skeletal muscle nerves in the human body, affords versatile device functions. Novel micromachined copper buckles and grid wires are fabricated and their superiority in electricity delivery and driving the IPMC component with less flexural rigidity is demonstrated. In addition, soft conductive wires realized on a polydimethylsiloxane structure function as electrical signal transmitters. A light-emitting diode integrated with the developed actuator offers directional guiding light ability while the actuator performs a snake-like motion. The electrical conductivity and Young’s modulus of the key actuator components are investigated, and flexural rigidity and dynamic behavior analyses of the actuator under electrical manipulation are elaborated.

Double-section curvature tunable functional actuator with micromachined buckle and grid wire for electricity delivery

International Nuclear Information System (INIS)

Feng, Guo-Hua; Hou, Sheng-You

2015-01-01

This paper presents an ionic polymer metal composite (IPMC)-driven tentacle-like biocompatible flexible actuator with double-section curvature tunability. This actuator, possessing an embedded electrical transmission ability that mimics skeletal muscle nerves in the human body, affords versatile device functions. Novel micromachined copper buckles and grid wires are fabricated and their superiority in electricity delivery and driving the IPMC component with less flexural rigidity is demonstrated. In addition, soft conductive wires realized on a polydimethylsiloxane structure function as electrical signal transmitters. A light-emitting diode integrated with the developed actuator offers directional guiding light ability while the actuator performs a snake-like motion. The electrical conductivity and Young’s modulus of the key actuator components are investigated, and flexural rigidity and dynamic behavior analyses of the actuator under electrical manipulation are elaborated. (paper)

Predictive modeling, simulation, and optimization of laser processing techniques: UV nanosecond-pulsed laser micromachining of polymers and selective laser melting of powder metals

Science.gov (United States)

Criales Escobar, Luis Ernesto

One of the most frequently evolving areas of research is the utilization of lasers for micro-manufacturing and additive manufacturing purposes. The use of laser beam as a tool for manufacturing arises from the need for flexible and rapid manufacturing at a low-to-mid cost. Laser micro-machining provides an advantage over mechanical micro-machining due to the faster production times of large batch sizes and the high costs associated with specific tools. Laser based additive manufacturing enables processing of powder metals for direct and rapid fabrication of products. Therefore, laser processing can be viewed as a fast, flexible, and cost-effective approach compared to traditional manufacturing processes. Two types of laser processing techniques are studied: laser ablation of polymers for micro-channel fabrication and selective laser melting of metal powders. Initially, a feasibility study for laser-based micro-channel fabrication of poly(dimethylsiloxane) (PDMS) via experimentation is presented. In particular, the effectiveness of utilizing a nanosecond-pulsed laser as the energy source for laser ablation is studied. The results are analyzed statistically and a relationship between process parameters and micro-channel dimensions is established. Additionally, a process model is introduced for predicting channel depth. Model outputs are compared and analyzed to experimental results. The second part of this research focuses on a physics-based FEM approach for predicting the temperature profile and melt pool geometry in selective laser melting (SLM) of metal powders. Temperature profiles are calculated for a moving laser heat source to understand the temperature rise due to heating during SLM. Based on the predicted temperature distributions, melt pool geometry, i.e. the locations at which melting of the powder material occurs, is determined. Simulation results are compared against data obtained from experimental Inconel 625 test coupons fabricated at the National

Single-molecule magnet behavior in an octanuclear dysprosium(iii) aggregate inherited from helical triangular Dy3 SMM-building blocks.

Science.gov (United States)

Zhang, Li; Zhang, Peng; Zhao, Lang; Wu, Jianfeng; Guo, Mei; Tang, Jinkui

2016-06-28

An unprecedented octanuclear dysprosium(iii) cluster with the formula [Dy8L6(μ3-OH)4(μ2-CH3O)2(CH3OH)6(H2O)2]·6H2O·10CH3OH·2CH3CN () based on a nonlinearly tritopic aroylhydrazone ligand H3L has been isolated, realizing the successful linking of pairwise interesting triangular Dy3 SMMs. It is noteworthy that two enantiomers (Λ and Δ configurations) individually behaving as a coordination-induced chirality presented in the Dy3 helicate are connected in the meso Dy8 cluster. Remarkably, alternating-current magnetic susceptibility measurements revealed that the Dy8 cluster shows typical SMM behavior inherited from its Dy3 helical precursor. It is one of the rare polynuclear Lnn SMMs (n > 7) under zero dc field.

Modeling the Microstructure Curvature of Boron-Doped Silicon in Bulk Micromachined Accelerometer

Directory of Open Access Journals (Sweden)

Xiaoping He

2013-01-01

Full Text Available Microstructure curvature, or buckling, is observed in the micromachining of silicon sensors because of the doping of impurities for realizing certain electrical and mechanical processes. This behavior can be a key source of error in inertial sensors. Therefore, identifying the factors that influence the buckling value is important in designing MEMS devices. In this study, the curvature in the proof mass of an accelerometer is modeled as a multilayered solid model. Modeling is performed according to the characteristics of the solid diffusion mechanism in the bulk-dissolved wafer process (BDWP based on the self-stopped etch technique. Moreover, the proposed multilayered solid model is established as an equivalent composite structure formed by a group of thin layers that are glued together. Each layer has a different Young’s modulus value and each undergoes different volume shrinkage strain owing to boron doping in silicon. Observations of five groups of proof mass blocks of accelerometers suggest that the theoretical model is effective in determining the buckling value of a fabricated structure.

Optical temperature sensor and thermal expansion measurement using a femtosecond micromachined grating in 6H-SiC.

Science.gov (United States)

DesAutels, G Logan; Powers, Peter; Brewer, Chris; Walker, Mark; Burky, Mark; Anderson, Gregg

2008-07-20

An optical temperature sensor was created using a femtosecond micromachined diffraction grating inside transparent bulk 6H-SiC, and to the best of our knowledge, this is a novel technique of measuring temperature. Other methods of measuring temperature using fiber Bragg gratings have been devised by other groups such as Zhang and Kahrizi [in MEMS, NANO, and Smart Systems (IEEE, 2005)]. This temperature sensor was, to the best of our knowledge, also used for a novel method of measuring the linear and nonlinear coefficients of the thermal expansion of transparent and nontransparent materials by means of the grating first-order diffracted beam. Furthermore the coefficient of thermal expansion of 6H-SiC was measured using this new technique. A He-Ne laser beam was used with the SiC grating to produce a first-order diffracted beam where the change in deflection height was measured as a function of temperature. The grating was micromachined with a 20 microm spacing and has dimensions of approximately 500 microm x 500 microm (l x w) and is roughly 0.5 microm deep into the 6H-SiC bulk. A minimum temperature of 26.7 degrees C and a maximum temperature of 399 degrees C were measured, which gives a DeltaT of 372.3 degrees C. The sensitivity of the technique is DeltaT=5 degrees C. A maximum deflection angle of 1.81 degrees was measured in the first-order diffracted beam. The trend of the deflection with increasing temperature is a nonlinear polynomial of the second-order. This optical SiC thermal sensor has many high-temperature electronic applications such as aircraft turbine and gas tank monitoring for commercial and military applications.

Micromachining of commodity plastics by proton beam writing and fabrication of spatial resolution test-chart for neutron radiography

International Nuclear Information System (INIS)

Sakai, T.; Yasuda, R.; Iikura, H.; Nojima, T.; Matsubayashi, M.; Kada, W.; Kohka, M.; Satoh, T.; Ohkubo, T.; Ishii, Y.; Takano, K.

2013-01-01

Proton beam writing is a direct-write technique and a promising method for the micromachining of commodity plastics such as acrylic resins. Herein, we describe the fabrication of microscopic devices made from a relatively thick (∼75 μm) acrylic sheet using proton beam writing. In addition, a software package that converts image pixels into coordinates data was developed, and the successful fabrication of a very fine jigsaw puzzle was achieved. The size of the jigsaw puzzle pieces was 50 × 50 μm. For practical use, a prototype of a line and space test-chart was also successfully fabricated for the determination of spatial resolution in neutron radiography

Si Micro-turbine by Proton BeamWriting and Porous Silicon Micromachining

International Nuclear Information System (INIS)

Rajta, I.; Szilasi, S.Z.; Fekete, Z.

2008-01-01

Complete text of publication follows. A 3D Si micro-turbine characterized by high aspect ratio vertical walls was formed by the combination of proton beam writing (PBW) and subsequent selective porous Si (PS) etching. Crystal damages generated by the implanted protons result in increased resistivity, thereby limit or even prevent the current to flow through the implanted area during electrochemical etching. Characteristic feature of the proposed process is that the shape of the micro electromechanical (MEMS) components is defined by two implantation energies. A higher energy is applied for defining the housing of the device while the lower energy is used to write the moving components. The implantation energies were selected such as to result appropriate difference between the two projected ranges, thereby providing structures with different height after development. The thickness of the walls of the moving component and the isotropic etching profile of the electrochemical PS formation was also taken into consideration. The electrochemical etching is driven until the sacrificial PS layer completely under etches the moving components, but the etch-front does not reach the bottom of the housing. Therefore, the dissolution of PS results in a ready-to-operate device with a released moving component embedded in the cavity of the housing. The operation of the encapsulated device fabricated by the two-energy implantation is successfully demonstrated (Fig. 1). Rotation speed of the device is estimated in the range of thousands rpm, however, further analysis of the novel structure optimized for performance and MEMS compatible assembly will be done and precise characteristics will be determined by adequate optical read-out method. The feasibility of Proton Beam Writing combined with Porous Si Micromachining and conventional Si processing steps was successfully demonstrated by fabricating Si microturbine chip. The aligned, two-energy proton beam implantation can provide high

MREIT experiments with 200 µA injected currents: a feasibility study using two reconstruction algorithms, SMM and harmonic BZ

International Nuclear Information System (INIS)

Arpinar, V E; Muftuler, L T; Hamamura, M J; Degirmenci, E

2012-01-01

Magnetic resonance electrical impedance tomography (MREIT) is a technique that produces images of conductivity in tissues and phantoms. In this technique, electrical currents are applied to an object and the resulting magnetic flux density is measured using magnetic resonance imaging (MRI) and the conductivity distribution is reconstructed using these MRI data. Currently, the technique is used in research environments, primarily studying phantoms and animals. In order to translate MREIT to clinical applications, strict safety standards need to be established, especially for safe current limits. However, there are currently no standards for safe current limits specific to MREIT. Until such standards are established, human MREIT applications need to conform to existing electrical safety standards in medical instrumentation, such as IEC601. This protocol limits patient auxiliary currents to 100 µA for low frequencies. However, published MREIT studies have utilized currents 10–400 times larger than this limit, bringing into question whether the clinical applications of MREIT are attainable under current standards. In this study, we investigated the feasibility of MREIT to accurately reconstruct the relative conductivity of a simple agarose phantom using 200 µA total injected current and tested the performance of two MREIT reconstruction algorithms. These reconstruction algorithms used are the iterative sensitivity matrix method (SMM) by Ider and Birgul (1998 Elektrik 6 215–25) with Tikhonov regularization and the harmonic B Z proposed by Oh et al (2003 Magn. Reason. Med. 50 875–8). The reconstruction techniques were tested at both 200 µA and 5 mA injected currents to investigate their noise sensitivity at low and high current conditions. It should be noted that 200 µA total injected current into a cylindrical phantom generates only 14.7 µA current in imaging slice. Similarly, 5 mA total injected current results in 367 µA in imaging slice. Total acquisition

SMM J04135+10277: A CANDIDATE EARLY-STAGE ''WET-DRY'' MERGER OF TWO MASSIVE GALAXIES AT z = 2.8

Energy Technology Data Exchange (ETDEWEB)

Riechers, Dominik A., E-mail: dr@astro.cornell.edu [Astronomy Department, California Institute of Technology, MC 249-17, 1200 East California Boulevard, Pasadena, CA 91125 (United States)

2013-03-10

We report interferometric imaging of CO(J = 3{yields}2) emission toward the z = 2.846 submillimeter-selected galaxy SMM J04135+10277, using the Combined Array for Research in Millimeter-wave Astronomy (CARMA). SMM J04135+10277 was previously thought to be a gas-rich, submillimeter-selected quasar, with the highest molecular gas mass among high-z quasars reported in the literature. Our maps at {approx}6 Multiplication-Sign improved linear resolution relative to earlier observations spatially resolve the emission on {approx}1.''7 scales, corresponding to a (lensing-corrected) source radius of {approx}5.2 kpc. They also reveal that the molecular gas reservoir, and thus, likely the submillimeter emission, is not associated with the host galaxy of the quasar, but with an optically faint gas-rich galaxy at 5.''2, or 41.5 kpc projected distance from the active galactic nucleus (AGN). The obscured gas-rich galaxy has a dynamical mass of M{sub dyn} sin{sup 2} i = 5.6 Multiplication-Sign 10{sup 11} M{sub Sun }, corresponding to a gas mass fraction of {approx_equal}21%. Assuming a typical M{sub BH}/M{sub *} ratio for z {approx}> 2 quasars, the two galaxies in this system have an approximate mass ratio of {approx}1.9. Our findings suggest that this quasar-starburst galaxy pair could represent an early stage of a rare major, gas-rich/gas-poor ({sup w}et-dry{sup )} merger of two massive galaxies at z = 2.8, rather than a single, gas-rich AGN host galaxy. Such systems could play an important role in the early buildup of present-day massive galaxies through a submillimeter-luminous starburst phase, and may remain hidden in larger numbers among rest-frame far-infrared-selected quasar samples at low and high redshift.

Intracardiac ultrasound scanner using a micromachine (MEMS) actuator.

Science.gov (United States)

Zara, J M; Bobbio, S M; Goodwin-Johansson, S; Smith, S W

2000-01-01

Catheter-based intracardiac ultrasound offers the potential for improved guidance of interventional cardiac procedures. The objective of this research is the development of catheter-based mechanical sector scanners incorporating high frequency ultrasound transducers operating at frequencies up to 20 MHz. The authors' current transducer assembly consists of a single 1.75 mm by 1.75 mm, 20 MHz, PZT element mounted on a 2 mm by 2 mm square, 75 mum thick polyimide table that pivots on 3-mum thick gold plated polyimide hinges. The hinges also serve as the electrical connections to the transducer. This table-mounted transducer is tilted using a miniature linear actuator to produce a sector scan. This linear actuator is an integrated force array (IFA), which is an example of a micromachine, i.e., a microelectromechanical system (MEMS). The IFA is a thin (2.2 mum) polyimide membrane, which consists of a network of hundreds of thousands of micron scale deformable capacitors made from pairs of metallized polyimide plates. IFAs contract with an applied voltage of 30-120 V and have been shown to produce strains as large as 20% and forces of up to 8 dynes. The prototype transducer and actuator assembly was fabricated and interfaced with a GagePCI analog to digital conversion board digitizing 12 bit samples at a rate of 100 MSamples/second housed in a personal computer to create a single channel ultrasound scanner. The deflection of the table transducer in a low viscosity insulating fluid (HFE 7100, 3M) is up to +/-10 degrees at scan rates of 10-60 Hz. Software has been developed to produce real-time sector scans on the PC monitor.

Micromachined fiber optic Fabry-Perot underwater acoustic probe

Science.gov (United States)

Wang, Fuyin; Shao, Zhengzheng; Hu, Zhengliang; Luo, Hong; Xie, Jiehui; Hu, Yongming

2014-08-01

One of the most important branches in the development trend of the traditional fiber optic physical sensor is the miniaturization of sensor structure. Miniature fiber optic sensor can realize point measurement, and then to develop sensor networks to achieve quasi-distributed or distributed sensing as well as line measurement to area monitoring, which will greatly extend the application area of fiber optic sensors. The development of MEMS technology brings a light path to address the problems brought by the procedure of sensor miniaturization. Sensors manufactured by MEMS technology possess the advantages of small volume, light weight, easy fabricated and low cost. In this paper, a fiber optic extrinsic Fabry-Perot interferometric underwater acoustic probe utilizing micromachined diaphragm collaborated with fiber optic technology and MEMS technology has been designed and implemented to actualize underwater acoustic sensing. Diaphragm with central embossment, where the embossment is used to anti-hydrostatic pressure which would largely deflect the diaphragm that induce interferometric fringe fading, has been made by double-sided etching of silicon on insulator. By bonding the acoustic-sensitive diaphragm as well as a cleaved fiber end in ferrule with an outer sleeve, an extrinsic Fabry-Perot interferometer has been constructed. The sensor has been interrogated by quadrature-point control method and tested in field-stable acoustic standing wave tube. Results have been shown that the recovered signal detected by the sensor coincided well with the corresponding transmitted signal and the sensitivity response was flat in frequency range from 10 Hz to 2kHz with the value about -154.6 dB re. 1/μPa. It has been manifest that the designed sensor could be used as an underwater acoustic probe.

Micromachined silicon acoustic delay line with 3D-printed micro linkers and tapered input for improved structural stability and acoustic directivity

International Nuclear Information System (INIS)

Cho, Y; Kumar, A; Xu, S; Zou, J

2016-01-01

Recent studies have shown that micromachined silicon acoustic delay lines can provide a promising solution to achieve real-time photoacoustic tomography without the need for complex transducer arrays and data acquisition electronics. To achieve deeper imaging depth and wider field of view, a longer delay time and therefore delay length are required. However, as the length of the delay line increases, it becomes more vulnerable to structural instability due to reduced mechanical stiffness. In this paper, we report the design, fabrication, and testing of a new silicon acoustic delay line enhanced with 3D printed polymer micro linker structures. First, mechanical deformation of the silicon acoustic delay line (with and without linker structures) under gravity was simulated by using finite element method. Second, the acoustic crosstalk and acoustic attenuation caused by the polymer micro linker structures were evaluated with both numerical simulation and ultrasound transmission testing. The result shows that the use of the polymer micro linker structures significantly improves the structural stability of the silicon acoustic delay lines without creating additional acoustic attenuation and crosstalk. In addition, the improvement of the acoustic acceptance angle of the silicon acoustic delay lines was also investigated to better suppress the reception of unwanted ultrasound signals outside of the imaging plane. These two improvements are expected to provide an effective solution to eliminate current limitations on the achievable acoustic delay time and out-of-plane imaging resolution of micromachined silicon acoustic delay line arrays. (paper)

Research on the effect of coverage rate on the surface quality in laser direct writing process

Science.gov (United States)

Pan, Xuetao; Tu, Dawei

2017-07-01

Direct writing technique is usually used in femtosecond laser two-photon micromachining. The size of the scanning step is an important factor affecting the surface quality and machining efficiency of micro devices. According to the mechanism of two-photon polymerization, combining the distribution function of light intensity and the free radical concentration theory, we establish the mathematical model of coverage of solidification unit, then analyze the effect of coverage on the machining quality and efficiency. Using the principle of exposure equivalence, we also obtained the analytic expressions of the relationship among the surface quality characteristic parameters of microdevices and the scanning step, and carried out the numerical simulation and experiment. The results show that the scanning step has little influence on the surface quality of the line when it is much smaller than the size of the solidification unit. However, with increasing scanning step, the smoothness of line surface is reduced rapidly, and the surface quality becomes much worse.

Sapphire capillaries for laser-driven wakefield acceleration in plasma. Fs-laser micromachining and characterization

International Nuclear Information System (INIS)

Schwinkendorf, Jan-Patrick

2012-05-01

Plasma wakefields are a promising approach for the acceleration of electrons with ultrahigh (10 to 100 GV/m) electric fields. Nowadays, high-intensity laser pulses are routinely utilized to excite these large-amplitude plasma waves. However, several detrimental effects such as laser diffraction, electron-wake dephasing and laser depletion may terminate the acceleration process. Two of these phenomena can be mitigated or avoided by the application of capillary waveguides, e.g. fabricated out of sapphire for longevity. Capillaries may compensate for laser diffraction like a fiber and allow for the creation of tapered gas-density profiles working against the dephasing between the accelerating wave and the particles. Additionally, they offer the possibility of controlled particle injection. This thesis is reporting on the set up of a laser for fs-micromachining of capillaries of almost arbitrary shapes and a test stand for density-profile characterization. These devices will permit the creation of tailored gas-density profiles for controlled electron injection and acceleration inside plasma.

Sapphire capillaries for laser-driven wakefield acceleration in plasma. Fs-laser micromachining and characterization

Energy Technology Data Exchange (ETDEWEB)

Schwinkendorf, Jan-Patrick

2012-08-15

Plasma wakefields are a promising approach for the acceleration of electrons with ultrahigh (10 to 100 GV/m) electric fields. Nowadays, high-intensity laser pulses are routinely utilized to excite these large-amplitude plasma waves. However, several detrimental effects such as laser diffraction, electron-wake dephasing and laser depletion may terminate the acceleration process. Two of these phenomena can be mitigated or avoided by the application of capillary waveguides, e.g. fabricated out of sapphire for longevity. Capillaries may compensate for laser diffraction like a fiber and allow for the creation of tapered gas-density profiles working against the dephasing between the accelerating wave and the particles. Additionally, they offer the possibility of controlled particle injection. This thesis is reporting on the set up of a laser for fs-micromachining of capillaries of almost arbitrary shapes and a test stand for density-profile characterization. These devices will permit the creation of tailored gas-density profiles for controlled electron injection and acceleration inside plasma.

Experimental Study of the Ultrasonic Vibration-Assisted Abrasive Waterjet Micromachining the Quartz Glass

Directory of Open Access Journals (Sweden)

Rongguo Hou

2018-01-01

Full Text Available The ultrasonic vibration is used to enhance the capability of the abrasive water micromachining glass. And, the ultrasonic vibration is activated on the abrasive waterjet nozzle. The quality of the flow is improved, and the velocity of the abrasive is increased because of the addition of the ultrasonic energy. The relevant experimental results indicate that the erosion depth and the material volume removal of the glass are obviously increased when ultrasonic vibration is working. As for the influence of process parameters on the material removal of the glass such as vibration amplitude, system pressure, distance of the standoff, and abrasive size, the experimental results indicate that the system pressure and vibration contribute greatly to the glass material removal. Also, the erosion depth and the volume of material removal are increased with the increase in the vibration amplitude and system pressure. There are some uplifts found at the edge of erosion pit. Then, it can be inferred that the plastic method is an important material removal method during the machining process of ultrasonic vibration-assisted abrasive waterjet.

On-chip micromachined dipole antenna with parasitic radiator for mm-wave wireless systems

KAUST Repository

Sallam, Mai O.; Serry, Mohamed; Shamim, Atif; Sedky, Sherif; Soliman, Ezzeldin A.

2016-01-01

In this paper, we present a micromachined dipole antenna with parasitic radiator. The antenna is designed for operation at 60 GHz. It consists of two Ig/2 dipole radiators fed by coplanar strips waveguide. Two slightly shorter dipoles are placed in proximity to the main radiators. They act as parasitic dipole arms which increase the bandwidth of the antenna. Two versions of the same antenna topology are presented in this paper in which one uses a high resistivity silicon substrate while the other uses a low resistivity one. The proposed antenna was optimized using HFSS and the final design was simulated using both HFSS and CST for verifying the obtained results. Both simulators are in good agreement. They show that the antenna has very good radiation characteristics where its directivity is around 7.5 dBi. The addition of the parasitic arms increased the bandwidth of the antenna from 1.3 GHz (3.62 GHz) to 4.3 GHz (7.44 GHz) when designed on high (low) resistivity silicon substrate.

To study the effect of different electrolytes and their concentrations on electrochemical micromachining

Science.gov (United States)

Singh, Ramandeep

2018-04-01

The machining of materials on micro-meter and sub-micrometre is considered the technology of future. Due to challenging applications of biomedical and aerospace industries, the traditional manufacturing techniques lacks in dimensional accuracy. Thus for such industries, the technique that can control micron tolerances is Electrochemical Micromachining (EMM). Hard metals and alloys can also be machined by this technique. Thus to develop a novel EMM system setup and to investigate the effect of three different electrolytes i.e NaCl, NaNO3 and HCl with their different concentrations, the current study was conducted. Stainless Steel-304 and copper were chosen as the work piece material in the present study. Taguchi L18 orthogonal array was used for the best combination of experiment. According to the present investigation most prominent factor affecting the material removal (MR) comes out was electrolyte. HCl provides the better MR among other electrolytes i.e. NaNO3 and NaCl. The amount of MR increased with the increase in the concentration of electrolyte.

On-chip micromachined dipole antenna with parasitic radiator for mm-wave wireless systems

KAUST Repository

Sallam, Mai O.

2016-12-19

In this paper, we present a micromachined dipole antenna with parasitic radiator. The antenna is designed for operation at 60 GHz. It consists of two Ig/2 dipole radiators fed by coplanar strips waveguide. Two slightly shorter dipoles are placed in proximity to the main radiators. They act as parasitic dipole arms which increase the bandwidth of the antenna. Two versions of the same antenna topology are presented in this paper in which one uses a high resistivity silicon substrate while the other uses a low resistivity one. The proposed antenna was optimized using HFSS and the final design was simulated using both HFSS and CST for verifying the obtained results. Both simulators are in good agreement. They show that the antenna has very good radiation characteristics where its directivity is around 7.5 dBi. The addition of the parasitic arms increased the bandwidth of the antenna from 1.3 GHz (3.62 GHz) to 4.3 GHz (7.44 GHz) when designed on high (low) resistivity silicon substrate.

Wireless Displacement Sensing of Micromachined Spiral-Coil Actuator Using Resonant Frequency Tracking

Directory of Open Access Journals (Sweden)

Mohamed Sultan Mohamed Ali

2014-07-01

Full Text Available This paper reports a method that enables real-time displacement monitoring and control of micromachined resonant-type actuators using wireless radiofrequency (RF. The method is applied to an out-of-plane, spiral-coil microactuator based on shape-memory-alloy (SMA. The SMA spiral coil forms an inductor-capacitor resonant circuit that is excited using external RF magnetic fields to thermally actuate the coil. The actuation causes a shift in the circuit’s resonance as the coil is displaced vertically, which is wirelessly monitored through an external antenna to track the displacements. Controlled actuation and displacement monitoring using the developed method is demonstrated with the microfabricated device. The device exhibits a frequency sensitivity to displacement of 10 kHz/µm or more for a full out-of-plane travel range of 466 µm and an average actuation velocity of up to 155 µm/s. The method described permits the actuator to have a self-sensing function that is passively operated, thereby eliminating the need for separate sensors and batteries on the device, thus realizing precise control while attaining a high level of miniaturization in the device.

Chemical vapor detection using a capacitive micromachined ultrasonic transducer.

Science.gov (United States)

Lee, Hyunjoo J; Park, Kwan Kyu; Kupnik, Mario; Oralkan, O; Khuri-Yakub, Butrus T

2011-12-15

Distributed sensing of gas-phase chemicals using highly sensitive and inexpensive sensors is of great interest for many defense and consumer applications. In this paper we present ppb-level detection of dimethyl methylphosphonate (DMMP), a common simulant for sarin gas, with a ppt-level resolution using an improved capacitive micromachined ultrasonic transducer (CMUT) as a resonant chemical sensor. The improved CMUT operates at a higher resonant frequency of 47.7 MHz and offers an improved mass sensitivity of 48.8 zg/Hz/μm(2) by a factor of 2.7 compared to the previous CMUT sensors developed. A low-noise oscillator using the CMUT resonant sensor as the frequency-selective device was developed for real-time sensing, which exhibits an Allan deviation of 1.65 Hz (3σ) in the presence of a gas flow; this translates into a mass resolution of 80.5 zg/μm(2). The CMUT resonant sensor is functionalized with a 50-nm thick DKAP polymer developed at Sandia National Laboratory for dimethyl methylphosphonate (DMMP) detection. To demonstrate ppb-level detection of the improved chemical sensor system, the sensor performance was tested at a certified lab (MIT Lincoln Laboratory), which is equipped with an experimental chemical setup that reliably and accurately delivers a wide range of low concentrations down to 10 ppb. We report a high volume sensitivity of 34.5 ± 0.79 pptv/Hz to DMMP and a good selectivity of the polymer to DMMP with respect to dodecane and 1-octanol.

Fabricación de micro-componentes mediante arranque de viruta. análisis del acabado superficial en aleaciones de aluminio y titanio

Directory of Open Access Journals (Sweden)

Francisco Mata Cabrera

2011-07-01

Se proponen modelos de predicción de la rugosidad, con buen grado de aproximación, para ayudar a la caracterización de los procesos de micro-mecanizado. Micro-machining is the most adequate technology for manufacturing of micro-components in the industry. This is a manufacturing precision process with applications in certain industrial field, for example the machining construction. The objective of this research is to analyze the surface quality in micro-machining processes and to evaluate her possible application in mechanical industry (surface roughness, geometry, aspect, etc. This work presents the experimental study of surface roughness (Ra and Rt using a specific micro-turning process. The measures of surface roughness reveal how it is possible to obtain superficial very good qualities up to diameters of 0.05 mm. For low diameters, it worsens the superficial quality and the faults of form increase, due to the low inflexibility of the piece. Prediction models of surface roughness are proposed to the characterization of micro-machining processes.  

Development of micro capacitive accelerometer for subsurface microseismic measurement. Second Report; Micromachining ni yoru chika danseiha kenshutsu no tame no silicone yoryogata kasokudo sensor no seisaku. 2

Energy Technology Data Exchange (ETDEWEB)

Nishizawa, M; Lim, G; Niitsuma, H; Esashi, M [Tohoku University, Sendai (Japan)

1997-10-22

Micromachining-aided manufacture is under way of a silicon capacitive accelerator sensor, high in sensitivity and broad in bandwidth, for detecting subsurface microseismic waves. The sensor detects acceleration by use of changes in capacities of the top and bottom capacitors generated when a spring-supported weight experiences displacement upon application of acceleration to the said weight. A diode bridge circuit is employed as the circuit for detecting acceleration. As for sensitivity of the sensor, when the virtual noise inputted into the electronic circuit is presumed at 1{mu}V and the circuit driving voltage at 5V, the sensor minimum detectability will be 2.5mgal in the presence of a 3{mu}m gap between the weight and an electrode plate. The natural vibration frequency is set at 1kHz. Such specifications may be realized using the current micromachining technology, and possibilities are that the bandwidth will be further expanded when the sensor is used in a servo-type configuration. The effort is still at the stage of acceleration sensor manufacturing, with a stopper just formed for the silicon weight. 9 refs., 6 figs., 1 tab.

Yb3+ can be much better than Dy3+: SMM properties and controllable self-assembly of novel lanthanide 3,5-dinitrobenzoate-acetylacetonate complexes.

Science.gov (United States)

Gavrikov, Andrey V; Efimov, Nikolay N; Ilyukhin, Andrey B; Dobrokhotova, Zhanna V; Novotortsev, Vladimir M

2018-05-01

The first representatives of the binuclear lanthanide 3,5-dinitrobenzoate-acetylacetonate complexes, namely isostructural compounds [Ln(dnbz)(acac)2(H2O)(EtOH)]2 (Ln = Eu (1), Gd (2), Tb (3), Dy (4), Ho (5), Er (6), Tm (7), and Yb (8); dnbz - 3,5-dinitrobenzoate anion; acac - acetylacetonate (pentane-2,4-dionate) anion) were prepared and characterized. The SMM behavior of the Yb compound 8 was shown to be surprisingly less sensitive to the composition of the Yb3+ coordination environment in comparison with that of the Dy derivative. For Yb compound 8, the anisotropy barrier is Δeff/kB = 26 K under the dc field of 2000 Oe. This value is the highest one currently known for binuclear Yb complexes.

Generation of programmable temporal pulse shape and applications in micromachining

Science.gov (United States)

Peng, X.; Jordens, B.; Hooper, A.; Baird, B. W.; Ren, W.; Xu, L.; Sun, L.

2009-02-01

In this paper we presented a pulse shaping technique on regular solid-state lasers and the application in semiconductor micromachining. With a conventional Q-switched laser, all of the parameters can be adjusted over only limited ranges, especially the pulse width and pulse shape. However, some laser link processes using traditional laser pulses with pulse widths of a few nanoseconds to a few tens of nanoseconds tend to over-crater in thicker overlying passivation layers and thereby cause IC reliability problems. Use of a laser pulse with a special shape and a fast leading edge, such as tailored pulse, is one technique for controlling link processing. The pulse shaping technique is based on light-loop controlled optical modulation to shape conventional Q-switched solid-state lasers. One advantage of the pulse shaping technique is to provide a tailored pulse shape that can be programmed to have more than one amplitude value. Moreover, it has the capability of providing programmable tailored pulse shapes with discrete amplitude and time duration components. In addition, it provides fast rising and fall time of each pulse at fairly high repetition rate at 355nm with good beam quality. The regular-to-shaped efficiency is up to 50%. We conclude with a discussion of current results for laser processing of semiconductor memory link structures using programmable temporal pulse shapes. The processing experiments showed promising results with shaped pulse.

Effect of the Detector Width and Gas Pressure on the Frequency Response of a Micromachined Thermal Accelerometer

Directory of Open Access Journals (Sweden)

Johann Courteaud

2011-05-01

Full Text Available In the present work, the design and the environmental conditions of a micromachined thermal accelerometer, based on convection effect, are discussed and studied in order to understand the behavior of the frequency response evolution of the sensor. It has been theoretically and experimentally studied with different detector widths, pressure and gas nature. Although this type of sensor has already been intensively examined, little information concerning the frequency response modeling is currently available and very few experimental results about the frequency response are reported in the literature. In some particular conditions, our measurements show a cut-off frequency at −3 dB greater than 200 Hz. By using simple cylindrical and planar models of the thermal accelerometer and an equivalent electrical circuit, a good agreement with the experimental results has been demonstrated.

Design and Fabrication of Piezoresistive Based Encapsulated Poly-Si Cantilevers for Bio/chemical Sensing

Science.gov (United States)

Krishna, N. P. Vamsi; Murthy, T. R. Srinivasa; Reddy, K. Jayaprakash; Sangeeth, K.; Hegde, G. M.

Cantilever-based sensing is a growing research field not only within micro regime but also in nano technology. The technology offers a method for rapid, on-line and in-situ monitoring of specific bio/chemical substances by detecting the nanomechanical responses of a cantilever sensor. Cantilever with piezoresistive based detection scheme is more attractive because of its electronics compatibility. Majority of commercially available micromachined piezoresistive sensors are bulk micromachined devices and are fabricated using single crystal silicon wafers. As substrate properties are not important in surface micromachining, the expensive silicon wafers can be replaced by cheaper substrates, such as poly-silicon, glass or plastic. Here we have designed SU-8 based bio/chemical compatible micro electro mechanical device that includes an encapsulated polysilicon piezoresistor for bio/chemical sensing. In this paper we report the design, fabrication and analysis of the encapsulated poly-Si cantilevers. Design and theoretical analysis are carried out using Finite Element Analysis software. For fabrication of poly-silicon piezoresistive cantilevers we followed the surface micromachining process steps. Preliminary characterization of the cantilevers is presented.

Proton beam micromachining on strippable aqueous base developable negative resist

International Nuclear Information System (INIS)

Rajta, I.; Uzonyi, I.; Baradacs, E.; Chatzichristidi, M.; Raptis, I.; Valamontes, E.S.

2004-01-01

Complete text of publication follows. Proton Beam Micromachining (PBM, also known as P-beam writing), a novel direct- write process for the production of 3D microstructures, can be used to make multilevel structures in a single layer of resist by varying the ion energy. The interaction between the bombarding ions and the target material is mainly ionization, and very few ions suffer high angle nuclear collisions, therefore structures made with PBM have smooth near vertical side walls. The most commony applied resists in PBM are the positive, conventional, polymethyl methacrylate (PMMA); and the negative, chemically amplified, SU-8 (Micro Chem Corp). SU-8 is an epoxy based resist suitable also for LIGA and UV-LIGA processes, it offers good sensitivity, good process latitude, very high aspect ratio and therefore it dominates in the high aspect ratio micromachining applications. SU-8 requires 30 nC/mm 2 fluence for PBM irradiations at 2 MeV protons. Its crosslinking chemistry is based on the eight epoxy rings in the polymer chain, which provide a very dense three dimensional network in the presence of suitably activated photo acid generators (PAGs) which is very difficult to be stripped away after development. Thus, stripping has to be assisted with plasma processes or with special liquid removers. Moreover, the SU-8 developer is organic, propylene glycol methyl ether acetate (PGMEA), and thus environmentally non-friendly. To overcome the SU-8 stripping limitations, design of a negative resist system where solubility change is not based solely on cross- linking but also on the differentiation of hydrophilicity between exposed and non-exposed areas is desirable. A new resist formulation, fulfilling the above specifications has been developed recently [1]. This formulation is based on a specific grade epoxy novolac (EP) polymer, a partially hydrogenated poly-4-hydroxy styrene (PHS) polymer, and an onium salt as photoacid generator (PAG), and has been successfully

Micromachined sensor for stress measurement and micromechanical study of free-standing thin films for MEMS applications

Science.gov (United States)

Zhang, Ping

Microelectromechanical systems (MEMS) have a wide range of applications. In the field of wireless and microwave technology, considerable attention has been given to the development and integration of MEMS-based RF (radio frequency) components. An RF MEMS switch requires low insertion loss, high isolation, and low actuation voltage - electrical aspects that have been extensively studied. The mechanical requirements of the switch, such as low sensitivity to built-in stress and high reliability, greatly depend on the micromechanical properties of the switch materials, and have not been thoroughly explored. RF MEMS switches are typically in the form of a free-standing thin film structure. Large stress gradients and across-wafer stress variations developed during fabrication severely degrade their electrical performance. A micromachined stress measurement sensor has been developed that can potentially be employed for in-situ monitoring of stress evolution and stress variation. The sensors were micromachined using five masks on two wafer levels, each measuring 5x3x1 mm. They function by means of an electron tunneling mechanism, where a 2x2 mm silicon nitride membrane elastically deflects under an applied deflection voltage via an external feedback circuitry. For the current design, the sensors are capable of measuring tensile stresses up to the GPa range under deflection voltages of 50--100 V. Sensor functionality was studied by finite element modeling and a theoretical analysis of square membrane deflection. While the mechanical properties of thin films on substrates have been extensively studied, studies of free-standing thin films have been limited due to the practical difficulties in sample handling and testing. Free-standing Al and Al-Ti thin films specimens have been successfully fabricated and microtensile and stress relaxation tests have been performed using a custom-designed micromechanical testing apparatus. A dedicated TEM (transmission electron microscopy

Short-pulse-width micromachining of hard materials using DPSS Nd:YAG lasers

Science.gov (United States)

Heglin, Michael; Govorkov, Sergei V.; Scaggs, Michael J.; Theoharidis, Haris; Schoelzel, T.

2002-06-01

The material processing of an industrial, short-pulse duration DPPS YAG laser producing peak powers greater than 0.2MW is discussed in this paper. This peak power provides sufficient materials processing capability to meet the micro machining needs in the automotive, semiconductor, micro- electronic, medical and telecommunication industries. All hard and soft materials including: plastics, metals, ceramics, diamond and other crystalline materials are suitable candidates for the processing capability of this laser. Micro level features can be machined in these materials to a depth in excess of 1mm with high quality results. In most applications feature sizes can be achieved that are not possible or economical with existing technologies. The optical beam delivery system requirements, and overall micro-machining set-up are also described. The drilling and cutting versatility down to feature sizes of less than 7 micrometers , as well as, complex shapes are shown. The wavelength, pulse length, and peakpower are described and relate to their effect on recast, micro-cracking and material removal rates. Material removal effects related to progressive penetration into the material will be reviewed. The requirements of this DPSS laser technology to meet the operational requirements for high duty cycle operation in industrial environments is covered along with processing flexibility and lower operating cost.

Fiscal 1997 report on technological results. R and D on micromachine technology (Development of micro-factory technology); 1997 nendo micromachine gijutsu no kenkyu kaihatsu seika hokokusho. Microfactory gijutsu kaihatsu

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-03-01

Activities are conducted in search of a micromachine system in which devices and equipment relating to machining, assembly, transportation, inspection, etc., in use for a manufacturing process are integrated in a narrow space, for the purpose of conserving energy through the miniaturization of the process of manufacturing small industrial products. With the activities in the two fields of (1) R and D of systematization technology (experimental system for micro fabrication/assembly) and (2) comprehensive investigation and research, examination on detailed specification for the experimental system was carried out, as were the examination of element technologies, element device operating experiments, technological investigation, etc.. In (1), sophistication of the element technologies was contrived that were required for realizing each experimental system, while the detailed specification of each experimental system was decided. Further, a part of the element devices was experimentally manufactured, with the basic functions verified. In (2), research studies were compiled on radio interference for example in the case where various devices were integrated and highly densified through the formation of a micro-factory; also compiled was a joint research with Agency of Industrial Science and Technology, a research conducted for the purpose of building the conception of the micro-factory. (NEDO)

Strong and anisotropic superexchange in the single-molecule magnet (SMM) [MnIII(6)OsIII]3+: promoting SMM behavior through 3d-5d transition metal substitution.

Science.gov (United States)

Hoeke, Veronika; Stammler, Anja; Bögge, Hartmut; Schnack, Jürgen; Glaser, Thorsten

2014-01-06

The reaction of the in situ generated trinuclear triplesalen complex [(talent-Bu2)MnIII3(solv)n]3+ with (Ph4P)3[OsIII(CN)6] and NaClO4·H2O affords [MnIII6OsIII](ClO4)3 (= [{(talent-Bu2)MnIII3}2{OsIII(CN)6}](ClO4)3) in the presence of the oxidizing agent [(tacn)2NiIII](ClO4)3 (tacn =1,4,7-triazacyclononane), while the reaction of [(talent-Bu2)MnIII3(solv)n]3+ with K4[OsII(CN)6] and NaClO4·H2O yields [MnIII6OsII](ClO4)2 under an argon atmosphere. The molecular structure of [MnIII6OsIII]3+ as determined by single-crystal X-ray diffraction is closely related to the already published [MnIII6Mc]3+ complexes (Mc = CrIII, FeIII, CoIII, MnIII). The half-wave potential of the OsIII/OsII couple is E1/2 = 0.07 V vs Fc+/Fc. The FT-IR and electronic absorption spectra of [MnIII6OsII]2+ and [MnIII6OsIII]3+ exhibit distinct features of dicationic and tricationic [MnIII6Mc]n+ complexes, respectively. The dc magnetic data (μeff vs T, M vs B, and VTVH) of [MnIII6OsII]2+ are successfully simulated by a full-matrix diagonalization of a spin-Hamiltonian including isotropic exchange, zero-field splitting with full consideration of the relative orientation of the D-tensors, and Zeeman interaction, indicating antiferromagnetic MnIII–MnIII interactions within the trinuclear triplesalen subunits (JMn–Mn(1) = −(0.53 ± 0.01) cm–1, Ĥex = −2∑iSMM [MnIII6OsIII]3+ compared to the 3d analogue [MnIII6FeIII]3+ due to the stronger and anisotropic Mc–MnIII exchange interaction.

Simultaneous Solar Maximum Mission (SMM) and Very Large Array (VLA) observations of solar active regions

Science.gov (United States)

Willson, Robert F.

1991-01-01

Very Large Array observations at 20 cm wavelength can detect the hot coronal plasma previously observed at soft x ray wavelengths. Thermal cyclotron line emission was detected at the apex of coronal loops where the magnetic field strength is relatively constant. Detailed comparison of simultaneous Solar Maximum Mission (SMM) Satellite and VLA data indicate that physical parameters such as electron temperature, electron density, and magnetic field strength can be obtained, but that some coronal loops remain invisible in either spectral domain. The unprecedent spatial resolution of the VLA at 20 cm wavelength showed that the precursor, impulsive, and post-flare components of solar bursts originate in nearby, but separate loops or systems of loops.. In some cases preburst heating and magnetic changes are observed from loops tens of minutes prior to the impulsive phase. Comparisons with soft x ray images and spectra and with hard x ray data specify the magnetic field strength and emission mechanism of flaring coronal loops. At the longer 91 cm wavelength, the VLA detected extensive emission interpreted as a hot 10(exp 5) K interface between cool, dense H alpha filaments and the surrounding hotter, rarefield corona. Observations at 91 cm also provide evidence for time-correlated bursts in active regions on opposite sides of the solar equator; they are attributed to flare triggering by relativistic particles that move along large-scale, otherwise-invisible, magnetic conduits that link active regions in opposite hemispheres of the Sun.

Fabricating Bis(phthalocyaninato) Terbium SIM into Tetrakis(phthalocyaninato) Terbium SMM with Enhanced Performance through Sodium Coordination.

Science.gov (United States)

Chen, Yuxiang; Liu, Chao; Ma, Fang; Qi, Dongdong; Liu, Qingyun; Sun, Hao-Ling; Jiang, Jianzhuang

2018-04-23

The non-peripherally substituted 1,4,8,11,15,18,22,25-octa(butoxy)-phthalocyanine-involved unsymmetrical heteroleptic bis(phthalocyaninato) terbium double-decker, Tb(Pc){H[Pc(α-OC 4 H 9 ) 8 ]} (Pc=unsubstituted phthalocyanine) (1), was revealed to exhibit typical single ion magnet (SIM) behavior with effective energy barrier, 180 K (125 cm -1 ), and blocking temperature, 2 K, due to the severe deviation of the terbium coordination polyhedron from square-antiprismatic geometry. Fabrication of this double-decker compound into the novel tetrakis(phthalocyaninato) terbium pseudo-quadruple-decker Na 2 {Tb(Pc)[Pc(α-OC 4 H 9 ) 8 ]} 2 (2) single molecule magnet (SMM) not only optimizes the coordination polyhedron of terbium ion towards the square-antiprismatic geometry and intensifies the coordination field strength, but more importantly significantly enhances the molecular magnetic anisotropy in the unsymmetrical bis(phthalocyaninato) double-decker unit, along with the change of the counter cation from H + of 1 to Na + of 2, leading to an significantly enhanced magnetic behavior with spin-reversal energy barrier, 528 K (367 cm -1 ), and blocking temperature, 25 K. The present result is surely helpful towards developing novel tetrapyrrole lanthanide SMMs through rational design and self-assembly from bis(tetrapyrrole) lanthanide single ion magnet (SIM) building block. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Two Novel Measurements for the Drive-Mode Resonant Frequency of a Micromachined Vibratory Gyroscope

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Ancheng Wang

2013-11-01

Full Text Available To investigate the drive-mode resonance frequency of a micromachined vibratory gyroscope (MVG, one needs to measure it accurately and efficiently. The conventional approach to measure the resonant frequency is by performing a sweep frequency test and spectrum analysis. The method is time-consuming and inconvenient because of the requirements of many test points, a lot of data storage and off-line analyses. In this paper, we propose two novel measurement methods, the search method and track method, respectively. The former is based on the magnitude-frequency characteristics of the drive mode, utilizing a one-dimensional search technique. The latter is based on the phase-frequency characteristics, applying a feedback control loop. Their performances in precision, noise resistivity and efficiency are analyzed through detailed simulations. A test system is implemented based on a field programmable gate array (FPGA and experiments are carried out. By comparing with the common approach, feasibility and superiorities of the proposed methods are validated. In particular, significant efficiency improvements are achieved whereby the conventional frequency method consumes nearly 5,000 s to finish a measurement, while only 5 s is needed for the track method and 1 s for the search method.

MREIT experiments with 200 µA injected currents: a feasibility study using two reconstruction algorithms, SMM and harmonic B(Z).

Science.gov (United States)

Arpinar, V E; Hamamura, M J; Degirmenci, E; Muftuler, L T

2012-07-07

Magnetic resonance electrical impedance tomography (MREIT) is a technique that produces images of conductivity in tissues and phantoms. In this technique, electrical currents are applied to an object and the resulting magnetic flux density is measured using magnetic resonance imaging (MRI) and the conductivity distribution is reconstructed using these MRI data. Currently, the technique is used in research environments, primarily studying phantoms and animals. In order to translate MREIT to clinical applications, strict safety standards need to be established, especially for safe current limits. However, there are currently no standards for safe current limits specific to MREIT. Until such standards are established, human MREIT applications need to conform to existing electrical safety standards in medical instrumentation, such as IEC601. This protocol limits patient auxiliary currents to 100 µA for low frequencies. However, published MREIT studies have utilized currents 10-400 times larger than this limit, bringing into question whether the clinical applications of MREIT are attainable under current standards. In this study, we investigated the feasibility of MREIT to accurately reconstruct the relative conductivity of a simple agarose phantom using 200 µA total injected current and tested the performance of two MREIT reconstruction algorithms. These reconstruction algorithms used are the iterative sensitivity matrix method (SMM) by Ider and Birgul (1998 Elektrik 6 215-25) with Tikhonov regularization and the harmonic B(Z) proposed by Oh et al (2003 Magn. Reason. Med. 50 875-8). The reconstruction techniques were tested at both 200 µA and 5 mA injected currents to investigate their noise sensitivity at low and high current conditions. It should be noted that 200 µA total injected current into a cylindrical phantom generates only 14.7 µA current in imaging slice. Similarly, 5 mA total injected current results in 367 µA in imaging slice. Total

How to optimize ultrashort pulse laser interaction with glass surfaces in cutting regimes?

Energy Technology Data Exchange (ETDEWEB)

Bulgakova, Nadezhda M., E-mail: bulgakova@fzu.cz [HiLASE Centre, Institute of Physics ASCR, Za Radnicí 828, 25241 Dolní Břežany (Czech Republic); Institute of Thermophysics SB RAS, 1 Lavrentyev Ave., Novosibirsk 630090 (Russian Federation); Zhukov, Vladimir P. [Institute of Computational Technologies SB RAS, 6 Lavrentyev Ave., 630090 Novosibirsk (Russian Federation); Novosibirsk State Technical University, 20 Karl Marx Ave., 630073 Novosibirsk (Russian Federation); Collins, Adam R. [NCLA, NUI Galway, Galway (Ireland); Rostohar, Danijela; Derrien, Thibault J.-Y.; Mocek, Tomáš [HiLASE Centre, Institute of Physics ASCR, Za Radnicí 828, 25241 Dolní Břežany (Czech Republic)

2015-05-01

Highlights: • The factors influencing laser micromachining of transparent materials are analyzed. • Important role of ambient gas in laser processing is shown by numerical simulations. • The large potential of bi-wavelength laser processing is demonstrated. - Abstract: The interaction of short and ultrashort pulse laser radiation with glass materials is addressed. Particular attention is paid to regimes which are important in industrial applications such as laser cutting, drilling, functionalization of material surfaces, etc. Different factors influencing the ablation efficiency and quality are summarized and their importance is illustrated experimentally. The effects of ambient gas ionization in front of the irradiated target are also analyzed. A possibility to enhance laser coupling with transparent solids by bi-wavelength irradiation is discussed.

Analysis of the current density characteristics in through-mask electrochemical micromachining (TMEMM for fabrication of micro-hole arrays on invar alloy film

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Da-som JIN

2017-06-01

Full Text Available Invar alloy consisting of 64% iron and 36% nickel has been widely used for the production of shadow masks for organic light emitting diodes (OLEDs because of its low thermal expansion coefficient (1.86 × 10−6 cm/°C. To fabricate micro-hole arrays on 30 μm invar alloy film, through-mask electrochemical micromachining (TMEMM was developed and combined with a portion of the photolithography etching process. For precise hole shapes, patterned photoresist (PR film was applied as an insulating mask. To investigate the relationship between the current density and the material removal rate, the principle of the electrochemical machining was studied with a focus on the equation. The finite element method (FEM was used to verify the influence of each parameter on the current density on the invar alloy film surface. The parameters considered were the thickness of the PR mask, inter-electrode gap (IEG, and electrolyte concentration. Design of experiments (DOE was used to figure out the contribution of each parameter. A simulation was conducted with varying parameters to figure out their relationships with the current density. Optimization was conducted to select the suitable conditions. An experiment was carried out to verify the simulation results. It was possible to fabricate micro-hole arrays on invar alloy film using TMEMM, which is a promising method that can be applied to fabrications of OLEDs shadow masks.

Micromachined silicon parallel acoustic delay lines as time-delayed ultrasound detector array for real-time photoacoustic tomography

Science.gov (United States)

Cho, Y.; Chang, C.-C.; Wang, L. V.; Zou, J.

2016-02-01

This paper reports the development of a new 16-channel parallel acoustic delay line (PADL) array for real-time photoacoustic tomography (PAT). The PADLs were directly fabricated from single-crystalline silicon substrates using deep reactive ion etching. Compared with other acoustic delay lines (e.g., optical fibers), the micromachined silicon PADLs offer higher acoustic transmission efficiency, smaller form factor, easier assembly, and mass production capability. To demonstrate its real-time photoacoustic imaging capability, the silicon PADL array was interfaced with one single-element ultrasonic transducer followed by one channel of data acquisition electronics to receive 16 channels of photoacoustic signals simultaneously. A PAT image of an optically-absorbing target embedded in an optically-scattering phantom was reconstructed, which matched well with the actual size of the imaged target. Because the silicon PADL array allows a signal-to-channel reduction ratio of 16:1, it could significantly simplify the design and construction of ultrasonic receivers for real-time PAT.

Micromachined silicon parallel acoustic delay lines as time-delayed ultrasound detector array for real-time photoacoustic tomography

International Nuclear Information System (INIS)

Cho, Y; Chang, C-C; Zou, J; Wang, L V

2016-01-01

This paper reports the development of a new 16-channel parallel acoustic delay line (PADL) array for real-time photoacoustic tomography (PAT). The PADLs were directly fabricated from single-crystalline silicon substrates using deep reactive ion etching. Compared with other acoustic delay lines (e.g., optical fibers), the micromachined silicon PADLs offer higher acoustic transmission efficiency, smaller form factor, easier assembly, and mass production capability. To demonstrate its real-time photoacoustic imaging capability, the silicon PADL array was interfaced with one single-element ultrasonic transducer followed by one channel of data acquisition electronics to receive 16 channels of photoacoustic signals simultaneously. A PAT image of an optically-absorbing target embedded in an optically-scattering phantom was reconstructed, which matched well with the actual size of the imaged target. Because the silicon PADL array allows a signal-to-channel reduction ratio of 16:1, it could significantly simplify the design and construction of ultrasonic receivers for real-time PAT. (paper)

Fiscal 1997 technological survey report. R and D on micromachine technology (Development of high functional maintenance technology for power station equipment); 1997 nendo micromachine gijutsu no kenkyu kaihatsu seika hokokusho. Hatsuden shisetsuyo kokino maintenance gijutsu kaihatsu

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-03-01

Activities were conducted in search of micromachine technology for a high functional maintenance system that inspects and repairs abnormal conditions such as cracks in a heat exchanger or a piping system without disassembling it in a power generating station such as a thermal or nuclear power plant. The activities were proceeded in four areas of (1) experimental manufacturing of the system (an inline self-running environment recognizing system, an external inspection system for fine tube group, and a system capable of light internal operation such as welding), (2) R and D on sophistication technology for functional devices, (3) R and D on common basic technologies, and (4) comprehensive investigation and research. In (1), examination of detailed basic specifications was carried out, as were examination of element technologies, experimental manufacturing and operation test of element devices, and performance evaluation. Further, a part of element devices was made on an experimental basis, with the basic functions demonstrated. In the comprehensive investigation and research, a trend in the future maintenance technology in power generating equipment was obtained and pigeonholed. (NEDO)

Effect of Ligand Substitution around the Dy(III) on the SMM Properties of Dual-Luminescent Zn-Dy and Zn-Dy-Zn Complexes with Large Anisotropy Energy Barriers: A Combined Theoretical and Experimental Magnetostructural Study.

Science.gov (United States)

Costes, Jean Pierre; Titos-Padilla, Silvia; Oyarzabal, Itziar; Gupta, Tulika; Duhayon, Carine; Rajaraman, Gopalan; Colacio, Enrique

2016-05-02

The new dinuclear Zn(II)-Dy(III) and trinuclear Zn(II)-Dy(III)-Zn(II) complexes of formula [(LZnBrDy(ovan) (NO3)(H2O)](H2O)·0.5(MeOH) (1) and [(L(1)ZnBr)2Dy(MeOH)2](ClO4) (3) (L and L(1) are the dideprotonated forms of the N,N'-2,2-dimethylpropylenedi(3-methoxysalicylideneiminato and 2-{(E)-[(3-{[(2E,3E)-3-(hydroxyimino)butan-2-ylidene ]amino}-2,2-dimethylpropyl)imino]methyl}-6-methoxyphenol Schiff base compartmental ligands, respectively) have been prepared and magnetostructurally characterized. The X-ray structure of 1 indicates that the Dy(III) ion exhibits a DyO9 coordination sphere, which is made from four O atoms coming from the compartmental ligand (two methoxy terminal groups and two phenoxido bridging groups connecting Zn(II) and Dy(III) ions), other four atoms belonging to the chelating nitrato and ovanillin ligands, and the last one coming to the coordinated water molecule. The structure of 3 shows the central Dy(III) ion surrounded by two L(1)Zn units, so that the Dy(III) and Zn(II) ions are linked by phenoxido/oximato bridging groups. The Dy ion is eight-coordinated by the six O atoms afforded by two L(1) ligands and two O atoms coming from two methanol molecules. Alternating current (AC) dynamic magnetic measurements of 1, 3, and the previously reported dinuclear [LZnClDy(thd)2] (2) complex (where thd = 2,2,6,6-tetramethyl-3,5-heptanedionato ligand) indicate single molecule magnet (SMM) behavior for all these complexes with large thermal energy barriers for the reversal of the magnetization and butterfly-shaped hysteresis loops at 2 K. Ab initio calculations on 1-3 show a pure Ising ground state for all of them, which induces almost completely suppressed quantum tunnelling magnetization (QTM), and thermally assisted quantum tunnelling magnetization (TA-QTM) relaxations via the first excited Kramers doublet, leading to large energy barriers, thus supporting the observation of SMM behavior. The comparison between the experimental and theoretical

The Fantastic Voyage of the Trypanosome: A Protean Micromachine Perfected during 500 Million Years of Engineering

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Timothy Krüger

2018-02-01

Full Text Available The human body is constantly attacked by pathogens. Various lines of defence have evolved, among which the immune system is principal. In contrast to most pathogens, the African trypanosomes thrive freely in the blood circulation, where they escape immune destruction by antigenic variation and incessant motility. These unicellular parasites are flagellate microswimmers that also withstand the harsh mechanical forces prevailing in the bloodstream. They undergo complex developmental cycles in the bloodstream and organs of the mammalian host, as well as the disease-transmitting tsetse fly. Each life cycle stage has been shaped by evolution for manoeuvring in distinct microenvironments. Here, we introduce trypanosomes as blueprints for nature-inspired design of trypanobots, micromachines that, in the future, could explore the human body without affecting its physiology. We review cell biological and biophysical aspects of trypanosome motion. While this could provide a basis for the engineering of microbots, their actuation and control still appear more like fiction than science. Here, we discuss potentials and challenges of trypanosome-inspired microswimmer robots.

Micromachining of Al₂O₃-TiC ceramics by excimer laser

Directory of Open Access Journals (Sweden)

Oliveira, V.

1998-04-01

Full Text Available Micromachining of Al₂O₃-TiC ceramic using a KrF excimer laser was studied in the fluence range 2 to 8 J/cm² . The ablation rate decreases and the roughness increases with the first pulses but after about 200 pulses the process reaches a stationary stage where both roughness and ablation rate become constant. Observation of the processed areas by scanning electron microscopy showed that a globular topography is formed during the first stage and that the surface topography remains unchanged with further pulses. This globular topography is responsible for the variation of roughness and ablation rate observed during the first stage. EDS analysis showed that the globular features present an external region with higher titanium content and a core formed of unaffected material.

Se estudia el micromecanizado de cerámicas Al₂O₃-TiC mediante un láser de excímero de KrF con un rango de fluencia de 2 a 8 J/cm² . La velocidad de ablación disminuye y la rugosidad aumenta con los primeros pulsos. Sin embargo, después de 200 pulsos, el proceso alcanza el régimen estacionario, donde tanto la rugosidad como la velocidad de ablación permanecen constantes. La observación mediante SEM de determinadas áreas mostraban una topografía globular formada durante la primera etapa, mientras que con los siguientes pulsos permanece in cambios. Esta topografía globular es responsable de la variación de rugosidad y de la velocidad de ablación observada durante las primeras etapas del proceso. Los análisis de EDS sobre las zonas globulares mostraron la existencia de una región externa rica en titanio y un núcleo formado por el material sin afectar.

Thin film shape memory alloys for optical sensing applications

International Nuclear Information System (INIS)

Fu, Y Q; Luo, J K; Huang, W M; Flewitt, A J; Milne, W I

2007-01-01

Based on shape memory effect of the sputtered thin film shape memory alloys, different types of micromirror structures were designed and fabricated for optical sensing application. Using surface micromachining, TiNi membrane mirror structure has been fabricated, which can be actuated based on intrinsic two-way shape memory effect of the free-standing TiNi film. Using bulk micromachining, TiNi/Si and TiNi/Si 3 N 4 microcantilever mirror structures were fabricated

Detection of skeletal muscle metastasis: torso FDG PET-CT versus contrast-enhanced chest or abdomen CT.

Science.gov (United States)

So, Young; Yi, Jeong Geun; Song, Inyoung; Lee, Won Woo; Chung, Hyun Woo; Park, Jeong Hee; Moon, Sung Gyu

2015-07-01

Skeletal muscle metastasis (SMM) in cancer patients has not been sufficiently evaluated regarding prevalence and proper method of detection. To determine the prevalence of SMM and compare the diagnostic competencies for SMM of torso F-18 fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET-CT) and contrast-enhanced chest or abdomen CT. We investigated 18,225 PET-CT studies of 6359 cancer patients performed from 2005 to 2012. The PET-CT studies describing potential SMM were retrieved and the corresponding medical records were reviewed. The gold standard for SMM was histopathologically-proven SMM or imaging study-based disease progression. The detectability of SMM was compared between PET-CT and contrast-enhanced CT. Twenty-six patients had 84 SMM lesions, representing a SMM prevalence of 0.41%. Lung cancer was the most common SMM-associated malignancy (54%) and the gluteal/pelvic girdle muscle was the most frequently involved SMM site (37%). All 84 SMM lesions were visualized on PET-CT (100%). Of these PET-CT positive 84 SMM lesions, 51 lesions were in the CT field of view (FOV) (61%), whereas 33 lesions were out of the CT FOV (39%). Among these 51 lesions, 17 lesions showed rim-enhancing nodules/masses (33%), eight lesions showed homogeneously enhancing nodules (16%), three lesions showed heterogeneously enhancing nodules (6%), and 23 SMM lesions (45%) were non-diagnostic by CT. All 51 SMM lesions within CT FOV were detected on PET-CT (100%), whereas only 28 were visualized on CT (54.9%), resulting in a significant difference (P SMM was revealed by PET-CT. The prevalence of SMM was as low as 0.41% in the current large cohort of cancer patients. Torso PET-CT was a more competent modality than contrast-enhanced CT in the detection of SMM. © The Foundation Acta Radiologica 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Comparison of skeletal muscle mass to fat-free mass ratios among different ethnic groups.

Science.gov (United States)

Abe, T; Bemben, M G; Kondo, M; Kawakami, Y; Fukunaga, T

2012-01-01

Asians seem to have less skeletal muscle mass (SMM) than other ethnic groups, but it is not clear whether relative SMM, i.e., SMM / height square or SMM to fat-free mass (FFM) ratio, differs among different ethnic groups at the same level of body mass index (BMI). To compare the SMM to fat-free mass (FFM) ratio as well as anthropometric variables and body composition among 3 ethnic groups. Three hundred thirty-nine Japanese, 343 Brazilian, and 183 German men and women were recruited for this cross-sectional study. Muscle thickness (MTH) and subcutaneous fat thickness (FTH) were measured by ultrasound at nine sites on the anterior and posterior aspects of the body. FTH was used to estimate the body density, from which fat mass and fat-free mass (FFM) was calculated by using Brozek equation. Total SMM was estimated from ultrasound-derived prediction equations. Percentage body fat was similar among the ethnic groups in men, while Brazilians were higher than Japanese in women. In German men and women, absolute SMM and FFM were higher than in their Japanese and Brazilians counterparts. SMM index and SMM:FFM ratios were similar among the ethnic groups in women, excluding SMM:FFM ratio in Brazilian. In men, however, these relative values (SMM index and SMM:FFM ratio) were still higher in Germans. After adjusting for age and BMI, the SMM index and SMM:FFM ratios were lower in Brazilian men and women compared with the other two ethnic groups, while the SMM index and SMM:FFM ratios were similar in Japanese and German men and women, excluding SMM:FFM ratio in women. Our results suggest that relative SMM is not lower in Asian populations compared with European populations after adjusted by age and BMI.

DAMPAK PENERAPAN SMM ISO 9001:2000 TERHADAP KUALITAS LAYANAN AKADEMIK DAN LULUSAN FT UNY

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Sugiyono Sugiyono

2015-02-01

Full Text Available ABSTRACT This research aims at revealing the impact of the implimentation of ISO 9001:2000 towards the academic service quality (the service quality of lecturers, staffs, technicians, and department orginizer and the graduates’ quality (GPA and period of study. This evaluation was conducted by using descriptive research method and document analysis to reveal the fact of academic service beforeand after the implementation of ISO 9001:2000. The sample technique was using cluster sampling technique as PTM and PTTB departments were chosen. The target sample was 83 students in the seventh semestser and the dacuments in ISO secretariat from those two deperatments. Data collection techniques were using questionnaire and documentation (syallabus and lesson plan, yusisum data, learning evaluation, attandence list and assessement document. Data analysis method was using quatitive descriptive analysis. The findings showed the mean scores of acedemic sevice quality in PTBB Department had been fulfilling the expectation (3,12 while for PTM can be categorized as moderate level (2.97. The lowest score was found in the area of academic administration service, i.e. 3,02 for PTBB and 2,83 for PTM. Furthermore, it was found that The quality of PTBB graduates improved 0,02 and the period of study for (S1/ Bachelor degree fluctuated in 5,16 while the GPA of PTM was not stable yet but the students had shorter period of study. By seeing the findings, it can concluded that the implementation of ISO 9001-2000 was able to improve the administration service of academic but it did not guarantee to create qualified acadmic service to support the fulfilment of high GPA and short period of study. Keywords: graduates’ quality, SMM-ISO 9001-2000, quality of academic service

Texturing in titanium grade 2 surface irradiate with ultrashort pulse laser

International Nuclear Information System (INIS)

Nogueira, Alessandro Francelino

2015-01-01

The texturing laser micromachining is an important alternative to improve the bonding adhesion between composites and titanium, which are applied to structural components in the aerospace industry. The texturing running on titanium plates is due to the fact that the preferred joining technique for many composite materials is the adhesive bonding. In this work, titanium plates were texturized using laser ultrashort pulses temporal widths of femtoseconds. This process resulted in minimal heat transfer to the material, avoiding deformation of the titanium plate surface as well as the formation of resolidified material in the ablated region. These drawbacks have occurred with the use of nanoseconds pulses. Were performed three types of texturing using laser with femtosecond pulses, with variations in the distances between the machined lines. The analysis of the obtained surfaces found that the wettability increases when there is the increased distance between the texturing lines. Advancing in the analysis by optical profilometry of textured surfaces was observed that there is substantial increase in the volume available for penetration of structural adhesive when the distances between the textured lines are diminished. In tensile tests conducted it was observed that there is an increase in shear strength of the adhesive joint by reducing the distance between the textured lines. (author)

Achievement report on commissioned research of R and D in fiscal 2000 on micromachine technologies. Development of high function maintenance technology for power generation facilities; 2000 nendo kenkyu seika hokokusho. Hatsuden shisetsu you kokino mentenansu gijutsu kaihatsu

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-03-01

R and D has been carried out on a high function maintenance system that performs inspection and repair of anomalies such as internal cracks by using micromachines without need of disassembling heat exchangers and piping systems in power generation facilities. This paper summarizes the achievements in fiscal 2000. In the research of a prototype self-propelled system to recognize environment in tubes, the secondary prototype system integrating all of the elemental devices was fabricated, and its functions were verified. In the research of a prototype system to inspect outer surface of fine tube groups, a plurality of single machines that perform movement in narrow spaces on flat surface, interlocking, separation and flaw detection were connected to execute a vertical movement experiment. In the research of a prototype system for works internal to devices, fabrication and functional verification were conducted on the final prototype system which is equipped with functions of measuring very small nicks and performing repair works, which are mounted on the tip of a curved tube unit with multiple degrees of freedom. In the research of a functional device improving technology, a device that puts together artificial muscles, micro-joints, and a suspension device with very low friction was fabricated, and a functional verification was implemented thereon. (NEDO)

A novel prototyping method for die-level monolithic integration of MEMS above-IC

International Nuclear Information System (INIS)

Cicek, Paul-Vahe; Zhang, Qing; Saha, Tanmoy; Mahdavi, Sareh; Allidina, Karim; Gamal, Mourad El; Nabki, Frederic

2013-01-01

This work presents a convenient and versatile prototyping method for integrating surface-micromachined microelectromechanical systems (MEMS) directly above IC electronics, at the die level. Such localized implementation helps reduce development costs associated with the acquisition of full-sized semiconductor wafers. To demonstrate the validity of this method, variants of an IC-compatible surface-micromachining MEMS process are used to build different MEMS devices above a commercial transimpedance amplifier chip. Subsequent functional assessments for both the electronics and the MEMS indicate that the integration is successful, validating the prototyping methodology presented in this work, as well as the suitability of the selected MEMS technology for above-IC integration. (paper)

Recent advances in particle and droplet manipulation for lab-on-a-chip devices based on surface acoustic waves.

Science.gov (United States)

Wang, Zhuochen; Zhe, Jiang

2011-04-07

Manipulation of microscale particles and fluid liquid droplets is an important task for lab-on-a-chip devices for numerous biological researches and applications, such as cell detection and tissue engineering. Particle manipulation techniques based on surface acoustic waves (SAWs) appear effective for lab-on-a-chip devices because they are non-invasive, compatible with soft lithography micromachining, have high energy density, and work for nearly any type of microscale particles. Here we review the most recent research and development of the past two years in SAW based particle and liquid droplet manipulation for lab-on-a-chip devices including particle focusing and separation, particle alignment and patterning, particle directing, and liquid droplet delivery.

New Fabrication Method of Three-Electrode System on Cylindrical Capillary Surface as a Flexible Implantable Microneedle

Science.gov (United States)

Yang, Zhuoqing; Zhang, Yi; Itoh, Toshihiro; Maeda, Ryutaro

2013-04-01

In this present paper, a three-electrode system has been fabricated and integrated on the cylindrical polymer capillary surface by micromachining technology, which could be used as a flexible and implantable microneedle for glucose sensor application in future. A UV lithography system is successfully developed for high resolution alignment on cylindrical substrates. The multilayer alignment exposure for cylindrical polymer capillary substrate is for the first time realized utilizing the lithography system. The ±1 μm alignment precision has been realized on the 330 μm-outer diameter polymer capillary surface, on which the three-electrode structure consisting of two platinum electrodes and one Ag/AgCl reference electrode has been fabricated. The fabricated whole device as microneedle for glucose sensor application has been also characterized in 1 mol/L KCl and 0.02 mol/L K3Fe(CN)6 mix solution. The measured cyclic voltammetry curve shows that the prepared three-electrode system has a good redox property.

Surface photo reaction processes using synchrotron radiation; Hoshako reiki ni yoru hyomenko hanno process

Energy Technology Data Exchange (ETDEWEB)

Imaizumi, Y. [Tohoku University, Sendai (Japan). Institute for Materials Research; Yoshigoe, A. [Toyohashi University of Technology, Aichi (Japan); Urisu, T. [Toyohashi University of Technology, Aichi (Japan). Institute for Molecular Science

1997-08-20

This paper introduces the surface photo reaction processes using synchrotron radiation, and its application. A synchrotron radiation process using soft X-rays contained in electron synchrotron radiated light as an excited light source has a possibility of high-resolution processing because of its short wave length. The radiated light can excite efficiently the electronic state of a substance, and can induce a variety of photochemical reactions. In addition, it can excite inner shell electrons efficiently. In the aspect of its application, it has been found that, if radiated light is irradiated on surfaces of solids under fluorine-based reaction gas or Cl2, the surfaces can be etched. This technology is utilized practically. With regard to radiated light excited CVD process, it may be said that anything that can be deposited by the ordinary plasma CVD process can be deposited. Its application to epitaxial crystal growth may be said a nano processing application in thickness direction, such as forming an ultra-lattice structure, the application being subjected to expectation. In micromachine fabricating technologies, a possibility is searched on application of a photo reaction process of the radiated light. 5 refs., 6 figs.

Determination of the dissolution slowness surface by study of etched shapes I. Morphology of the dissolution slowness surface and theoretical etched shapes

Science.gov (United States)

Leblois, T.; Tellier, C. R.

1992-07-01

We propose a theoretical model for the anisotropic etching of crystals, in order to be applied in the micromachining. The originality of the model is due to the introduction of dissolution tensors to express the representative surface of the dissolution slowness. The knowledge of the equation of the slowness surface allows us to determine the trajectories of all the elements which compose the starting surface. It is then possible to construct the final etched shape by numerical simulation. Several examples are given in this paper which show that the final etched shapes are correlated to the extrema of the dissolution slowness. Since the slowness surface must be determined from experiments, emphasis is placed on difficulties encountered when we correlate theory to experiments. Nous avons modélisé le processus de dissolution anisotrope des cristaux en vue d'une application à la simulation des formes obtenues par photolithogravure chimique. La principale originalité de ce modèle tient à l'introduction de tenseurs de dissolution pour exprimer la surface représentative de la lenteur de dissolution. La connaissance de l'équation de la lenteur de dissolution permet de calculer les trajectoires des différents éléments constituant la surface de départ puis de reconstituer par simulation la forme dissoute. Les simulations démontrent que les formes limites des cristaux dissous sont corrélées aux extrema de la lenteur de dissolution. La détermination de la surface de la lenteur se faisant à partir de mesures expérimetales, nous nous sommes efforcés de montrer toutes les difficultés attachées à cette analyse.

Decanuclear Ln10 Wheels and Vertex-Shared Spirocyclic Ln5 Cores: Synthesis, Structure, SMM Behavior, and MCE Properties.

Science.gov (United States)

Das, Sourav; Dey, Atanu; Kundu, Subrata; Biswas, Sourav; Narayanan, Ramakirushnan Suriya; Titos-Padilla, Silvia; Lorusso, Giulia; Evangelisti, Marco; Colacio, Enrique; Chandrasekhar, Vadapalli

2015-11-16

The reaction of a Schiff base ligand (LH3) with lanthanide salts, pivalic acid and triethylamine in 1:1:1:3 and 4:5:8:20 stoichiometric ratios results in the formation of decanuclear Ln10 (Ln = Dy (1), Tb (2), and Gd (3)) and pentanuclear Ln5 complexes (Ln = Gd (4), Tb (5), and Dy (6)), respectively. The formation of Ln10 and Ln5 complexes are fully governed by the stoichiometry of the reagents used. Detailed magnetic studies on these complexes (1-6) have been carried out. Complex 1 shows a SMM behavior with an effective energy barrier for the reversal of the magnetization (Ueff) = 16.12(8) K and relaxation time (τo) = 3.3×10(-5) s under 4000 Oe direct current (dc) field. Complex 6 shows the frequency dependent maxima in the out-of-phase signal under zero dc field, without achieving maxima above 2 K. Complexes 3 and 4 show a large magnetocaloric effect with the following characteristic values: -ΔSm = 26.6 J kg(-1) K(-1) at T = 2.2 K for 3 and -ΔSm = 27.1 J kg(-1) K(-1) at T = 2.4 K for 4, both for an applied field change of 7 T. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fabrication of micro-prominences on PTFE surface using proton beam writing

Energy Technology Data Exchange (ETDEWEB)

Kitamura, Akane, E-mail: ogawa.akane@jaea.go.jp [Department of Advanced Radiation Technology, Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-Machi, Takasaki, Gunma 370-1292 (Japan); Satoh, Takahiro; Koka, Masashi [Department of Advanced Radiation Technology, Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-Machi, Takasaki, Gunma 370-1292 (Japan); Kobayashi, Tomohiro [Advanced Science Institute, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 350-0198 (Japan); Kamiya, Tomihiro [Department of Advanced Radiation Technology, Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-Machi, Takasaki, Gunma 370-1292 (Japan)

2013-07-01

Polytetrafluoroethylene (PTFE) is a typical fluoropolymer and it has several desirable technological properties such as electrical insulation, solid lubrication etc. However, the conventional microstructuring methods have not been well applied to PTFE due to its chemical inertness. Some effective micromachining using synchrotron radiation or ion beam irradiation has been reported. In this study, we create micro-prominences by raising the original surface using proton beam writing (PBW) without chemical etching. A conical prominence was formed by spiral drawing from the center with a 3 MeV proton beam. The body was porous, and the bulk PTFE below the prominence changed to fragmented structures. With decreasing writing speed, the prominence became taller but the height peaked. The prominence gradually reduced in size after the speed reached the optimum value. We expect that these porous projections with high aspect ratio will be versatile in medical fields and microelectromechanical systems (MEMS) technology.

Micromachining and dicing of sapphire, gallium nitride and micro LED devices with UV copper vapour laser

International Nuclear Information System (INIS)

Gu, E.; Jeon, C.W.; Choi, H.W.; Rice, G.; Dawson, M.D.; Illy, E.K.; Knowles, M.R.H.

2004-01-01

Gallium nitride (GaN) and sapphire are important materials for fabricating photonic devices such as high brightness light emitting diodes (LEDs). These materials are strongly resistant to wet chemical etching and also, low etch rates restrict the use of dry etching. Thus, to develop alternative high resolution processing and machining techniques for these materials is important in fabricating novel photonic devices. In this work, a repetitively pulsed UV copper vapour laser (255 nm) has been used to machine and dice sapphire, GaN and micro LED devices. Machining parameters were optimised so as to achieve controllable machining and high resolution. For sapphire, well-defined grooves 30 μm wide and 430 μm deep were machined. For GaN, precision features such as holes on a tens of micron length scale have been fabricated. By using this technique, compact micro LED chips with a die spacing 100 and a 430 μm thick sapphire substrate have been successfully diced. Measurements show that the performances of LED devices are not influenced by the UV laser machining. Our results demonstrate that the pulsed UV copper vapour laser is a powerful tool for micromachining and dicing of photonic materials and devices

Post-CMOS Micromachining of Surface and Bulk Structures

Science.gov (United States)

2002-05-06

Structures iii Acknowledgements I would like to thank my advisors, Professor Gary K. Fedder and Professor Dave W. Greve, for their continuing support...Donnelly, Plasma Chem. Plasma Process, vol. 1, pp. 37, 1981. [54] J. L. Mauer, J. S. Logan, L. B. Zielinski , and G. S. Schwartz, J. Vac. Sci. Technol

Heterometallic Zn3 Ln3 Ensembles Containing (μ6 -CO3 ) Ligand and Triangular Disposition of Ln3+ ions: Analysis of Single-Molecule Toroic (SMT) and Single-Molecule Magnet (SMM) Behavior.

Science.gov (United States)

Goura, Joydeb; Colacio, Enrique; Herrera, Juan Manuel; Suturina, Elizaveta A; Kuprov, Ilya; Lan, Yanhua; Wernsdorfer, Wolfgang; Chandrasekhar, Vadapalli

2017-11-21

Two new heterometallic Zn 3 Ln 3 (Ln 3+ =Dy, Tb) complexes, with a double triangular topology of the metal ions, have been assembled from the polytopic Mannich base ligand 6,6'-{[2-(dimethylamino)ethylazanediyl]bis(methylene)}bis(2-methoxy-4-methylphenol) (H 2 L) with the aid of an in situ generated carbonate ligand from atmospheric CO 2 fixation. Theoretical calculations indicate axial ground states for the Ln 3+ ions in these complexes, with their local magnetic moments being almost coplanar and tangential to the Ln 3+ atoms that define the equilateral triangle. Therefore, they can be considered as single-molecule toroics (SMTs) with almost zero total magnetic moment. Micro-SQUID measurements on the Dy 3+ counterpart show hysteresis loops below 3 K that have an S-shape, with large coercive fields opening upon cooling. This behavior is typical of a single molecule magnet (SMM) with very slow zero-field relaxation. At around ±0.35 T, the loops have a broad step, which is due to a direct relaxation process and corresponds to an acceleration of the relaxation of the magnetization, also observed at this magnetic field from ac susceptibility measurements. Simulations suggest that the broad step corresponds to two level avoidance of crossing points where the spin chiral Kramers doublet meets excited states of the coupled manifold, whose position is defined by exchange and dipole interactions. The Tb 3+ counterpart does not exhibit SMM behavior, which is due to the fact that the degeneracy of the ground state of the exchange coupled system is lifted at zero field, thus favoring quantum tunneling of magnetization (QTM). © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Complex three-dimensional structures in Si{1 0 0} using wet bulk micromachining

International Nuclear Information System (INIS)

Pal, Prem; Sato, Kazuo

2009-01-01

Complex three-dimensional structures for microelectromechanical systems (MEMS) are fabricated in Si{1 0 0} wafers using wet bulk micromachining. The structures are divided into two categories: fixed and freestanding. The fabrication processes for both types utilize single wafers with sequentially deposited nitride and oxide layers, local oxidation of silicon (LOCOS) and two steps of wet anisotropic etching. The fixed structures contain perfectly sharp edges. Thermally deposited oxide is used as the material for the freestanding structures. Wet etching is performed in tetramethyl ammonium hydroxide (TMAH) with and without Triton X-100 (C 14 H 22 O(C 2 H 4 O) n , n = 9–10). For the fixed structures, both etching steps are performed either in 25 wt% TMAH + Triton or pure TMAH or both, depending upon the type of the structures. In the case of freestanding systems, TMAH + Triton is utilized first, followed by pure TMAH. The fabrication methods enable densely arrayed structures, allowing the manufacture of corrugated diaphragms, compact size liquid (or gas) flow delivery systems, newly shaped mold for soft MEMS structures (e.g. PDMS (polydimethylsiloxane)) and other applications. The present research is an approach to fabricate advanced MEMS structures, extending the range of 3D structures fabricated by silicon anisotropic etching

Examination of returned solar-max surfaces for impacting orbital debris and meteoroids

Science.gov (United States)

Kessler, D. J.; Zook, H. A.; Potter, A. E.; Mckay, D. S.; Clanton, U. S.; Warren, J. L.; Watts, L. A.; Schultz, R. A.; Schramm, L. S.; Wentworth, S. J.

1985-01-01

Previous theoretical studies predicted that in certain regions of earth orbit, the man-made earth orbiting debris environment will soon exceed the interplanetary meteoroid environment for sizes smaller than 1 cm. The surfaces returned from the repaired Solar Max Mission (SMM) by STS 41-C on April 12, 1984, offered an excellent opportunity to examine both the debris and meteoroid environments. To date, approximately 0.7 sq. met. of the thermal insulation and 0.05 sq. met of the aluminum louvers have been mapped by optical microscope for crater diameters larger than 40 microns. Craters larger in diameter than about 100 microns found on the initial 75 micron thick Kapton first sheet on the MEB (Main Electronics Box) blanket are actually holes and constitute perforations through that blanket. The following populations have been found to date in impact sites on these blankets: (1) meteoritic material; (2) thermal paint particles; (3) aluminum droplets; and (4) waste particles.

Robust Magnetic Properties of a Sublimable Single-Molecule Magnet.

Science.gov (United States)

Kiefl, Evan; Mannini, Matteo; Bernot, Kevin; Yi, Xiaohui; Amato, Alex; Leviant, Tom; Magnani, Agnese; Prokscha, Thomas; Suter, Andreas; Sessoli, Roberta; Salman, Zaher

2016-06-28

The organization of single-molecule magnets (SMMs) on surfaces via thermal sublimation is a prerequisite for the development of future devices for spintronics exploiting the richness of properties offered by these magnetic molecules. However, a change in the SMM properties due to the interaction with specific surfaces is usually observed. Here we present a rare example of an SMM system that can be thermally sublimated on gold surfaces while maintaining its intact chemical structure and magnetic properties. Muon spin relaxation and ac susceptibility measurements are used to demonstrate that, unlike other SMMs, the magnetic properties of this system in thin films are very similar to those in the bulk, throughout the full volume of the film, including regions near the metal and vacuum interfaces. These results exhibit the robustness of chemical and magnetic properties of this complex and provide important clues for the development of nanostructures based on SMMs.

Implementing Statewide Severe Maternal Morbidity Review: The Illinois Experience.

Science.gov (United States)

Koch, Abigail R; Roesch, Pamela T; Garland, Caitlin E; Geller, Stacie E

2018-03-07

Severe maternal morbidity (SMM) rates in the United States more than doubled between 1998 and 2010. Advanced maternal age and chronic comorbidities do not completely explain the increase in SMM or how to effectively address it. The Centers for Disease Control and Prevention and American College of Obstetricians and Gynecologists have called for facility-level multidisciplinary review of SMM for potential preventability and have issued implementation guidelines. Within Illinois, SMM was identified as any intensive or critical care unit admission and/or 4 or more units of packed red blood cells transfused at any time from conception through 42 days postpartum. All cases meeting this definition were counted during statewide surveillance. Cases were selected for review on the basis of their potential to yield insights into factors contributing to preventable SMM or best practices preventing further morbidity or death. If the SMM review committee deemed a case potentially preventable, it identified specific factors associated with missed opportunities and made actionable recommendations for quality improvement. Approximately 1100 cases of SMM were identified from July 1, 2016, to June 30, 2017, yielding a rate of 76 SMM cases per 10 000 pregnancies. Reviews were conducted on 142 SMM cases. Most SMM cases occurred during delivery hospitalization and more than half were delivered by cesarean section. Hemorrhage was the primary cause of SMM (>50% of the cases). Facility-level SMM review was feasible and acceptable in statewide implementation. States that are planning SMM reviews across obstetric facilities should permit ample time for translation of recommendations to practice. Although continued maternal mortality reviews are valuable, they are not sufficient to address the increasing rates of SMM and maternal death. In-depth multidisciplinary review offers the potential to identify factors associated with SMM and interventions to prevent women from moving along the

Modeling and analysis of micro-WEDM process of titanium alloy (Ti–6Al–4V using response surface approach

Directory of Open Access Journals (Sweden)

P. Sivaprakasam

2014-12-01

Full Text Available Micro-machining technology is effectively used in modern manufacturing industries. This paper investigates the influence of three different input parameters such as voltage, capacitance and feed rate of micro-wire electrical discharge machining (micro-WEDM performances of material removal rate (MRR, Kerf width (KW and surface roughness (SR using response surface methodology with central composite design (CCD. The experiments are carried out on titanium alloy (Ti–6Al–4V. The machining characteristics are significantly influenced by the electrical and non-electrical parameters in micro-WEDM process. Analysis of variance (ANOVA was performed to find out the significant influence of each factor. The model developed can use a genetic algorithm (GA to determine the optimal machining conditions using multi-objective optimization technique. The optimal machining performance of material removal rate, Kerf width and surface roughness are 0.01802 mm3/min, 101.5 μm and 0.789 μm, respectively, using this optimal machining conditions viz. voltage 100 V, capacitance 10 nF and feed rate 15 μm/s.

Ultraflat Tip-Tilt-Piston MEMS Deformable Mirror, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — This proposal describes a Phase II SBIR project to develop high-resolution, ultraflat micromirror array devices using advanced silicon surface micromachining...

Applications of picosecond lasers and pulse-bursts in precision manufacturing

Science.gov (United States)

Knappe, Ralf

2012-03-01

Just as CW and quasi-CW lasers have revolutionized the materials processing world, picosecond lasers are poised to change the world of micromachining, where lasers outperform mechanical tools due to their flexibility, reliability, reproducibility, ease of programming, and lack of mechanical force or contamination to the part. Picosecond lasers are established as powerful tools for micromachining. Industrial processes like micro drilling, surface structuring and thin film ablation benefit from a process, which provides highest precision and minimal thermal impact for all materials. Applications such as microelectronics, semiconductor, and photovoltaic industries use picosecond lasers for maximum quality, flexibility, and cost efficiency. The range of parts, manufactured with ps lasers spans from microscopic diamond tools over large printing cylinders with square feet of structured surface. Cutting glass for display and PV is a large application, as well. With a smart distribution of energy into groups of ps-pulses at ns-scale separation (known as burst mode) ablation rates can be increased by one order of magnitude or more for some materials, also providing a better surface quality under certain conditions. The paper reports on the latest results of the laser technology, scaling of ablation rates, and various applications in ps-laser micromachining.

Experimental and theoretical analysis of defocused CO2 laser microchanneling on PMMA for enhanced surface finish

Science.gov (United States)

Prakash, Shashi; Kumar, Subrata

2017-02-01

The poor surface finish of CO2 laser-micromachined microchannel walls is a major limitation of its utilization despite several key advantages, like low fabrication cost and low time consumption. Defocused CO2 laser beam machining is an effective solution for fabricating smooth microchannel walls on polymer and glass substrates. In this research work, the CO2 laser microchanneling process on PMMA has been analyzed at different beam defocus positions. Defocused processing has been investigated both theoretically and experimentally, and the depth of focus and beam diameter have been determined experimentally. The effect of beam defocusing on the microchannel width, depth, surface roughness, heat affected zone and microchannel profile were examined. A previously developed analytical model for microchannel depth prediction has been improved by incorporating the threshold energy density factor. A semi-analytical model for predicting the microchannel width at different defocus positions has been developed. A semi-empirical model has also been developed for predicting microchannel widths at different defocusing conditions for lower depth values. The developed models were compared and verified by performing actual experiments. Multi-objective optimization was performed to select the best optimum set of input parameters for achieving the desired surface roughness.

Laser-induced novel patterns: As smart strain actuators for new-age dental implant surfaces

International Nuclear Information System (INIS)

Çelen, Serap; Özden, Hüseyin

2012-01-01

Highlights: ► It is time for that paradigm shift and for an exploration of novel surfaces. ► We developed novel 3D smart surfaces as strain actuators by nanosecond laser pulse energies. ► We analyzed these smart surface morphologies using FEM. ► We estimated their internal stiffness values which play a great role on stress shielding effect. ► We gave the optimum operation parameters. - Abstract: Surface morphologies of titanium implants are of crucial importance for long-term mechanical adaptation for following implantation. One major problem is the stress shielding effect which originates from the mismatch of the bone and the implant elasticity. It is time for a paradigm shift and for an exploration of novel smart surfaces to prevent this problem. Several surface treatment methods have traditionally been used to modify the surface morphology of titanium dental implants. The laser micro-machining can be considered as a unique and promising, non-contact, no media, contamination free, and flexible treatment method for modifying surface properties of materials in the biomedical industry. The aim of the present study is two folds; to develop novel 3D smart surfaces which can be acted as strain actuators by nanosecond laser pulse energies and irradiation strategies. And analyze these smart surface morphologies using finite element methods in order to estimate their internal stiffness values which play a great role on stress shielding effect. Novel 3D smart strain actuators were prepared using an ytterbium fiber laser (λ = 1060 nm) with 200–250 ns pulse durations on commercial pure titanium dental implant material specimen surfaces and optimum operation parameters were suggested.

Severe Maternal Morbidity and Hospital Cost among Hospitalized Deliveries in the United States.

Science.gov (United States)

Chen, Han-Yang; Chauhan, Suneet P; Blackwell, Sean C

2018-05-03

 The objective of this study was to estimate the contemporary national rate of severe maternal morbidity (SMM) and its associated hospital cost during delivery hospitalization.  We conducted a retrospective study identifying all delivery hospitalizations in the United States between 2011 and 2012. We used data from the National (Nationwide) Inpatient sample of the Healthcare Cost and Utilization Project. The delivery hospitalizations with SMM were identified by having at least one of the 25 previously established list of diagnosis and procedure codes. Aggregate and mean hospital costs were estimated. A generalized linear regression model was used to examine the association between SMM and hospital costs.  Of 7,438,946 delivery hospitalizations identified, the rate of SMM was 154 per 10,000 delivery hospitalizations. Without any SMM, the mean hospital cost was $4,300 and with any SMM, the mean hospital cost was $11,000. After adjustment, comparing to those without any SMM, the mean cost of delivery hospitalizations with any SMM was 2.1 (95% confidence interval: 2.1-2.2) times higher, and this ratio increases from 1.7-fold in those with only one SMM to 10.3-fold in those with five or more concurrent SMM.  The hospital cost with any SMM was 2.1 times higher than those without any SMM. Our findings highlight the need to identify interventions and guide research efforts to mitigate the rate of SMM and its economic burden. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

CHARACTERIZATION OF TIGHTLY-ASSOCIATED SMOOTH MUSCLE MYOSIN-MYOSIN LIGHT CHAIN KINASE-CALMODULIN COMPLEXES*

OpenAIRE

Hong, Feng; Haldeman, Brian D.; John, Olivia A.; Brewer, Paul D.; Wu, Yi-Ying; Ni, Shaowei; Wilson, David P.; Walsh, Michael P.; Baker, Jonathan E.; Cremo, Christine R.

2009-01-01

A current popular model to explain phosphorylation of smooth muscle myosin (SMM) by smooth muscle myosin light chain kinase (MLCK) proposes that MLCK is bound tightly to actin but weakly to SMM. We found that MLCK and calmodulin (CaM) co-purify with unphosphorylated SMM (up-SMM) from chicken gizzard, suggesting that they are tightly bound. Although the MLCK:SMM molar ratio in SMM preparations was well below stoichiometric (1:73 ± 9), the ratio was ~ 23–37% of that in gizzard tissue. Fifteen t...

Rhombus-shaped tetranuclear [Ln4] complexes [Ln = Dy(III) and Ho(III)]: synthesis, structure, and SMM behavior.

Science.gov (United States)

Chandrasekhar, Vadapalli; Hossain, Sakiat; Das, Sourav; Biswas, Sourav; Sutter, Jean-Pascal

2013-06-03

The reaction of a new hexadentate Schiff base hydrazide ligand (LH3) with rare earth(III) chloride salts in the presence of triethylamine as the base afforded two planar tetranuclear neutral complexes: [{(LH)2Dy4}(μ2-O)4](H2O)8·2CH3OH·8H2O (1) and [{(LH)2Ho4}(μ2-O)4](H2O)8·6CH3OH·4H2O (2). These neutral complexes possess a structure in which all of the lanthanide ions and the donor atoms of the ligand remain in a perfect plane. Each doubly deprotonated ligand holds two Ln(III) ions in its two distinct chelating coordination pockets to form [LH(Ln)2](4+) units. Two such units are connected by four [μ2-O](2-) ligands to form a planar tetranuclear assembly with an Ln(III)4 core that possesses a rhombus-shaped structure. Detailed static and dynamic magnetic analysis of 1 and 2 revealed single-molecule magnet (SMM) behavior for complex 1. A peculiar feature of the χM" versus temperature curve is that two peaks that are frequency-dependent are revealed, indicating the occurrence of two relaxation processes that lead to two energy barriers (16.8 and 54.2 K) and time constants (τ0 = 1.4 × 10(-6) s, τ0 = 7.2 × 10(-7) s). This was related to the presence of two distinct geometrical sites for Dy(III) in complex 1.

Knowledge-based inspection:modelling complex processes with the integrated Safeguards Modelling Method (iSMM)

International Nuclear Information System (INIS)

Abazi, F.

2011-01-01

Increased level of complexity in almost every discipline and operation today raises the demand for knowledge in order to successfully run an organization whether to generate profit or to attain a non-profit mission. Traditional way of transferring knowledge to information systems rich in data structures and complex algorithms continue to hinder the ability to swiftly turnover concepts into operations. Diagrammatic modelling commonly applied in engineering in order to represent concepts or reality remains to be an excellent way of converging knowledge from domain experts. The nuclear verification domain represents ever more a matter which has great importance to the World safety and security. Demand for knowledge about nuclear processes and verification activities used to offset potential misuse of nuclear technology will intensify with the growth of the subject technology. This Doctoral thesis contributes with a model-based approach for representing complex process such as nuclear inspections. The work presented contributes to other domains characterized with knowledge intensive and complex processes. Based on characteristics of a complex process a conceptual framework was established as the theoretical basis for creating a number of modelling languages to represent the domain. The integrated Safeguards Modelling Method (iSMM) is formalized through an integrated meta-model. The diagrammatic modelling languages represent the verification domain and relevant nuclear verification aspects. Such a meta-model conceptualizes the relation between practices of process management, knowledge management and domain specific verification principles. This fusion is considered as necessary in order to create quality processes. The study also extends the formalization achieved through a meta-model by contributing with a formalization language based on Pattern Theory. Through the use of graphical and mathematical constructs of the theory, process structures are formalized enhancing

Theoretical modeling and equivalent electric circuit of a bimorph piezoelectric micromachined ultrasonic transducer.

Science.gov (United States)

Sammoura, Firas; Kim, Sang-Gook

2012-05-01

An electric circuit model for a circular bimorph piezoelectric micromachined ultrasonic transducer (PMUT) was developed for the first time. The model was made up of an electric mesh, which was coupled to a mechanical mesh via a transformer element. The bimorph PMUT consisted of two piezoelectric layers of the same material, having equal thicknesses, and sandwiched between three thin electrodes. The piezoelectric layers, having the same poling axis, were biased with electric potentials of the same magnitude but opposite polarity. The strain mismatches between the two layers created by the converse piezoelectric effect caused the membrane to vibrate and, hence, transmit a pressure wave. Upon receiving the echo of the acoustic wave, the membrane deformation led to the generation of electric charges as a result of the direct piezoelectric phenomenon. The membrane angular velocity and electric current were related to the applied electric field, the impinging acoustic pressure, and the moment at the edge of the membrane using two canonical equations. The transduction coefficients from the electrical to the mechanical domain and vice-versa were shown to be bilateral and the system was shown to be reversible. The circuit parameters of the derived model were extracted, including the transformer ratio, the clamped electric impedance, the spring-softening impedance, and the open-circuit mechanical impedance. The theoretical model was fully examined by generating the electrical input impedance and average plate displacement curves versus frequency under both air and water loading conditions. A PMUT composed of piezoelectric material with a lossy dielectric was also investigated and the maximum possible electroacoustical conversion efficiency was calculated.

A novel measurement method for the thermal properties of liquids by utilizing a bridge-based micromachined sensor

International Nuclear Information System (INIS)

Beigelbeck, Roman; Nachtnebel, Herbert; Kohl, Franz; Jakoby, Bernhard

2011-01-01

In recent decades, the demands for online monitoring of liquids in various applications have increased significantly. In this context, the sensing of the thermal transport parameters of liquids (i.e. thermal conductivity and diffusivity) may be an interesting alternative to well-established monitoring parameters like permittivity, mass density or shear viscosity. We developed a micromachined thermal property sensor, applicable to non-flowing liquids, featuring three in parallel microbridges, which carry either a heater or one of in total two thermistors. Its active sensing region was designed to achieve almost negligible spurious thermal shunts between heater and thermistors. This enables the adoption of a simple two-dimensional model to describe the heat transfer from the heater to the thermistors, which is mainly governed by the thermal properties of the sample liquid. Founded on this theoretical model, a novel measurement method for the thermal parameters was devised that relies solely on the frequency response of the measured peak temperature and allows simultaneous extraction of the thermal conductivity and diffusivity of liquids. In this contribution, we describe the device prototype, the model, the deduced measurement method and the experimental verification by means of test measurements carried out on five sample liquids

Smm-стратегия: практический аспект

OpenAIRE

Степнова, О.; Еременская, Л.; ХОШГИЯФЕХ РЕЗАИ МОХХАММАД АЛИ; Громова, М.

2014-01-01

В статье анализируется механизм привлечения внимания к бренду, посредством социальных платформ. Рассматриваются особенности, достоинства, недостатки SMM-стратегии.

Surface processing by high power excimer laser

Energy Technology Data Exchange (ETDEWEB)

Stehle, M [SOPRA, 92 - Bois-Colombes (France)

1995-03-01

Surface processing with lasers is a promising field of research and applications because lasers bring substantial advantages : laser beams work at distance, laser treatments are clean in respect of environment consideration and they offer innovative capabilities for surface treatment which cannot be reached by other way. Excimer lasers are pulsed, gaseous lasers which emit in UV spectral range - the most common are XeCl (308 nm), KrF (248 nm), ArF (193 nm). From 1980 up to 1994, many of them have been used for research, medical and industrial applications such as spectroscopy, PRK (photo-refractive keratotomy) and micro-machining. In the last six years, from 1987 up to 1993, efforts have been done in order to jump from 100 W average power up to 1 kW for XeCl laser at {lambda} = 308 nm. It was the aim of AMMTRA project in Japan as EU205 and EU213 Eureka projects in Europe. In this framework, SOPRA developed VEL (Very large Excimer Laser). In 1992, 1 kW (10 J x 100 Hz) millstone has been reached for the first time, this technology is based on X-Ray preionization and large laser medium (5 liters). Surface treatments based on this laser source are the main purpose of VEL Lasers. Some of them are given for instance : (a) Turbine blades made with metallic substrate and ceramic coatings on the top, are glazed in order to increase corrosion resistance of ceramic and metal sandwich. (b) Selective ablation of organic coatings deposited on fragile composite material is investigated in Aerospace industry. (c) Chock hardening of bulk metallic materials or alloys are investigated for automotive industry in order to increase wear resistance. (d) Ablation of thin surface oxides of polluted steels are under investigation in nuclear industry for decontamination. (J.P.N.).

Surface processing by high power excimer laser

International Nuclear Information System (INIS)

Stehle, M.

1995-01-01

Surface processing with lasers is a promising field of research and applications because lasers bring substantial advantages : laser beams work at distance, laser treatments are clean in respect of environment consideration and they offer innovative capabilities for surface treatment which cannot be reached by other way. Excimer lasers are pulsed, gaseous lasers which emit in UV spectral range - the most common are XeCl (308 nm), KrF (248 nm), ArF (193 nm). From 1980 up to 1994, many of them have been used for research, medical and industrial applications such as spectroscopy, PRK (photo-refractive keratotomy) and micro-machining. In the last six years, from 1987 up to 1993, efforts have been done in order to jump from 100 W average power up to 1 kW for XeCl laser at λ = 308 nm. It was the aim of AMMTRA project in Japan as EU205 and EU213 Eureka projects in Europe. In this framework, SOPRA developed VEL (Very large Excimer Laser). In 1992, 1 kW (10 J x 100 Hz) millstone has been reached for the first time, this technology is based on X-Ray preionization and large laser medium (5 liters). Surface treatments based on this laser source are the main purpose of VEL Lasers. Some of them are given for instance : a) Turbine blades made with metallic substrate and ceramic coatings on the top, are glazed in order to increase corrosion resistance of ceramic and metal sandwich. b) Selective ablation of organic coatings deposited on fragile composite material is investigated in Aerospace industry. c) Chock hardening of bulk metallic materials or alloys are investigated for automotive industry in order to increase wear resistance. d) Ablation of thin surface oxides of polluted steels are under investigation in nuclear industry for decontamination. (J.P.N.)

Impact of low skeletal muscle mass on non-lung cancer mortality after stereotactic body radiotherapy for patients with stage I non-small cell lung cancer.

Science.gov (United States)

Matsuo, Yukinori; Mitsuyoshi, Takamasa; Shintani, Takashi; Iizuka, Yusuke; Mizowaki, Takashi

2018-05-17

The purpose of the present study was to retrospectively evaluate impact of pre-treatment skeletal muscle mass (SMM) on overall survival and non-lung cancer mortality after stereotactic body radiotherapy (SBRT) for patients with stage I non-small cell lung cancer (NSCLC). One-hundred and eighty-six patients whose abdominal CT before the treatment was available were enrolled into this study. The patients were divided into two groups of SMM according to gender-specific thresholds for unilateral psoas area. Operability was judged by the treating physician or thoracic surgeon after discussion in a multi-disciplinary tumor board. Patients with low SMM tended to be elderly and underweight in body mass index compared with the high SMM. Overall survival in patients with the low SMM tended to be worse than that in the high SMM (41.1% and 55.9% at 5 years, P = 0.115). Cumulative incidence of non-lung cancer death was significantly worse in the low SMM (31.3% at 5 years compared with 9.7% in the high SMM, P = 0.006). Multivariate analysis identified SMM and operability as significant factors for non-lung cancer mortality. Impact of SMM on lung cancer death was not significant. No difference in rate of severe treatment-related toxicity was observed between the SMM groups. Low SMM is a significant risk factor for non-lung cancer death, which might lead to worse overall survival, after SBRT for stage I NSCLC. However, the low SMM does not increase lung cancer death or severe treatment-related toxicity. Copyright © 2018 Elsevier Inc. All rights reserved.

Evaluating Iowa Severe Maternal Morbidity Trends and Maternal Risk Factors: 2009-2014.

Science.gov (United States)

Frederiksen, Brittni N; Lillehoj, Catherine J; Kane, Debra J; Goodman, Dave; Rankin, Kristin

2017-09-01

Objectives To describe statewide SMM trends in Iowa from 2009 to 2014 and identify maternal characteristics associated with SMM, overall and by age group. Methods We used 2009-2014 linked Iowa birth certificate and hospital discharge data to calculate SMM based on a 25-condition definition and 24-condition definition. The 24-condition definition parallels the 25-condition definition, but excludes blood transfusions. We calculated SMM rates for all delivery hospitalizations (N = 196,788) using ICD-9-CM diagnosis and procedure codes. We used log-binomial regression to assess the association of SMM with maternal characteristics, overall and stratified by age groupings. Results In contrast to national rates, Iowa's 25-condition SMM rate decreased from 2009 to 2014. Based on the 25-condition definition, SMM rates were significantly higher among women 34 years compared to women 25-34 years. Blood transfusion was the most prevalent indicator, with hysterectomy and disseminated intravascular coagulation (DIC) among the top five conditions. Based on the 24-condition definition, younger women had the lowest SMM rates and older women had the highest SMM rates. SMM rates were also significantly higher among racial/ethnic minorities compared to non-Hispanic white women. Payer was the only risk factor differentially associated with SMM across age groups. First trimester prenatal care initiation was protective for SMM in all models. Conclusions High rates of blood transfusion, hysterectomy, and DIC indicate a need to focus on reducing hemorrhage in Iowa. Both younger and older women and racial/ethnic minorities are identified as high risk groups for SMM that may benefit from special consideration and focus.

Digestive recovery of sulfur-methyl-L-methionine and its bioaccessibility in Kimchi cabbages using a simulated in vitro digestion model system.

Science.gov (United States)

Lee, Hae-Rim; Cho, Sun-Duk; Lee, Woon Kyu; Kim, Gun-Hee; Shim, Soon-Mi

2014-01-15

Sulfur-methyl-L-methionine (SMM) has been known to provide various biological functions such as radical scavenging effect, inhibition of adipocyte differentiation, and prevention of gastric mucosal damage. Kimchi cabbages are known to be a major food source providing SMM but its bioaccessibility has not been studied. The objective of current study was to determine both the digestive stability of SMM and the amount released from Kimchi cabbages under a simulated in vitro digestion model system. The in vitro digestion model system simulating a human gastrointestinal tract was carried out for measuring digestive recovery and bioaccessibility of SMM. SMM was quantified by using high-performance liquid chromatography with a fluorescence detector. Recovery of an SMM standard after digestion was 0.68 and 0.65% for fasted and fed conditions, respectively, indicating that the digestive stability of the SMM standard was not affected by dietary energy or co-ingested food matrix. The SMM standard was also significantly stable in acidic pH (P < 0.05). The bioaccessibility of SMM from Kimchi cabbages was measured under a fasted condition, resulted in 8.83, 14.71 and 10.88%, for salivary, gastric and small intestinal phases, respectively. Results from our study suggest that SMM from Kimchi cabbages, a component of food sources, is more bioavailable than SMM by itself. © 2013 Society of Chemical Industry.

Wafer level packaging of MEMS

International Nuclear Information System (INIS)

Esashi, Masayoshi

2008-01-01

Wafer level packaging plays many important roles for MEMS (micro electro mechanical systems), including cost, yield and reliability. MEMS structures on silicon chips are encapsulated between bonded wafers or by surface micromachining, and electrical interconnections are made from the cavity. Bonding at the interface, such as glass–Si anodic bonding and metal-to-metal bonding, requires electrical interconnection through the lid vias in many cases. On the other hand, lateral electrical interconnections on the surface of the chip are used for bonding with intermediate melting materials, such as low melting point glass and solder. The cavity formed by surface micromachining is made using sacrificial etching, and the openings needed for the sacrificial etching are plugged using deposition sealing methods. Vacuum packaging methods and the structures for electrical feedthrough for the interconnection are discussed in this review. (topical review)

Comparative study on the usefulness of 99Tcm-MIBI scintigraphy, mammography, and fine-needle aspiration cytology in diagnosis of benign and malignant breast lesions

International Nuclear Information System (INIS)

Bai Yuekui; Cao Wenlan; Zhang Baoning; Liu Lin; Chen Shengzu; Tang Jin

2001-01-01

Objective: To evaluate the potential role of scintimammography (SMM) in conjunction with mammography (MG) and fine-needle aspiration cytology (FNAC) in detecting breast cancer. Methods: A total of 57 women with breast mass underwent SMM, 54 of them had MG and FNA cytology in addition to SMM. The result diagnoses were verified with histological examination. Results: Of the 3 patients who had lumpectomy, SMM showed normal. Of the 54 patients who had SMM, MG and FNAC, the number of suspected cancer in SMM, MG and FNAC was 31, 28 and 37, respectively. The sensitivity of SMM, MG and FNA cytology was 79.5%, 71.8% and 94.9%, respectively, and the accuracy was 78.9%, 72.2% and 96.3% respectively. In 57 patients, positive result was set at least by one of these techniques. Conclusions: SMM in conjunction with MG and FNA cytology is the best combination for the early detection and diagnosis of breast cancer. In women with suspected MG or abnormal FNA cytology and further investigations were required, SMM may be helpful as an additional noninvasive procedure

Micro Elector Mechanical Systems

International Nuclear Information System (INIS)

Yun, Jun Bo; Jo, Il Ju; Choi, Yoon Seok

1996-09-01

This book consists of seven chapters, which are the flow of the age from macro world to micro world, what is MEMS, semiconductor, micro machining and MEMS, where do MEMS goes to?, How to make MEMS, MEMS in the future and knowing about MEMS more than. This book is written to explain in ease and fun. It deals with MEMS in IT, BT, NT, ST, micro robot technology, basic process for making MEMS such as Bulk micromachining, surface micromachining LGA technology, DARPA and organization in domestic and overseas and academy and journal related MEMS.

Micromachined piezoresistive inclinometer with oscillator-based integrated interface circuit and temperature readout

International Nuclear Information System (INIS)

Dalola, Simone; Ferrari, Vittorio; Marioli, Daniele

2012-01-01

In this paper a dual-chip system for inclination measurement is presented. It consists of a MEMS (microelectromechanical system) piezoresistive accelerometer manufactured in silicon bulk micromachining and a CMOS (complementary metal oxide semiconductor) ASIC (application specific integrated circuit) interface designed for resistive-bridge sensors. The sensor is composed of a seismic mass symmetrically suspended by means of four flexure beams that integrate two piezoresistors each to detect the applied static acceleration, which is related to inclination with respect to the gravity vector. The ASIC interface is based on a relaxation oscillator where the frequency and the duty cycle of a rectangular-wave output signal are related to the fractional bridge imbalance and the overall bridge resistance of the sensor, respectively. The latter is a function of temperature; therefore the sensing element itself can be advantageously used to derive information for its own thermal compensation. DC current excitation of the sensor makes the configuration unaffected by wire resistances and parasitic capacitances. Therefore, a modular system results where the sensor can be placed remotely from the electronics without suffering accuracy degradation. The inclination measurement system has been characterized as a function of the applied inclination angle at different temperatures. At room temperature, the experimental sensitivity of the system results in about 148 Hz/g, which corresponds to an angular sensitivity around zero inclination angle of about 2.58 Hz deg −1 . This is in agreement with finite element method simulations. The measured output fluctuations at constant temperature determine an equivalent resolution of about 0.1° at midrange. In the temperature range of 25–65 °C the system sensitivity decreases by about 10%, which is less than the variation due to the microsensor alone thanks to thermal compensation provided by the current excitation of the bridge and the

Modeling, Fabrication and Testing of a Customizable Micromachined Hotplate for Sensor Applications.

Science.gov (United States)

Tommasi, Alessio; Cocuzza, Matteo; Perrone, Denis; Pirri, Candido Fabrizio; Mosca, Roberto; Villani, Marco; Delmonte, Nicola; Zappettini, Andrea; Calestani, Davide; Marasso, Simone Luigi

2016-12-30

In the sensors field the active sensing material frequently needs a controlled temperature in order to work properly. In microsystems technology, micro-machined hotplates represent a platform consisting of a thin suspended membrane where the sensing material can be deposited, usually integrating electrical stimuli and temperature readout. The micro-hotplate ensures a series of advantages such as miniaturized size, fast response, high sensitivity, low power consumption and selectivity for chemical sensing. This work compares the coplanar and the buried approach for the micro-hotplate heaters design with the aim to optimize the fabrication process and to propose a guideline for the choice of the suitable design with respect to the applications. In particular, robust Finite Element Method (FEM) models are set up in order to predict the electrical and thermal behavior of the micro-hotplates. The multiphysics approach used for the simulation allows to match as close as possible the actual device to the predictive model: geometries, materials, physics have been carefully linked to the fabricated devices to obtain the best possible accuracy. The materials involved in the fabrication process are accurately selected in order to improve the yield of the process and the performance of the devices. The fabricated micro-hotplates are able to warm the active region up to 400 °C (with a corresponding power consumption equal to 250 mW @ 400 °C) with a uniform temperature distribution in the buried micro-hotplate and a controlled temperature gradient in the coplanar one. A response time of about 70 ms was obtained on the virtual model, which perfectly agrees with the one measured on the fabricated device. Besides morphological, electrical and thermal characterizations, this work includes reliability tests in static and dynamic modes.

Modeling, Fabrication and Testing of a Customizable Micromachined Hotplate for Sensor Applications

Directory of Open Access Journals (Sweden)

Alessio Tommasi

2016-12-01

Full Text Available In the sensors field the active sensing material frequently needs a controlled temperature in order to work properly. In microsystems technology, micro-machined hotplates represent a platform consisting of a thin suspended membrane where the sensing material can be deposited, usually integrating electrical stimuli and temperature readout. The micro-hotplate ensures a series of advantages such as miniaturized size, fast response, high sensitivity, low power consumption and selectivity for chemical sensing. This work compares the coplanar and the buried approach for the micro-hotplate heaters design with the aim to optimize the fabrication process and to propose a guideline for the choice of the suitable design with respect to the applications. In particular, robust Finite Element Method (FEM models are set up in order to predict the electrical and thermal behavior of the micro-hotplates. The multiphysics approach used for the simulation allows to match as close as possible the actual device to the predictive model: geometries, materials, physics have been carefully linked to the fabricated devices to obtain the best possible accuracy. The materials involved in the fabrication process are accurately selected in order to improve the yield of the process and the performance of the devices. The fabricated micro-hotplates are able to warm the active region up to 400 °C (with a corresponding power consumption equal to 250 mW @ 400 °C with a uniform temperature distribution in the buried micro-hotplate and a controlled temperature gradient in the coplanar one. A response time of about 70 ms was obtained on the virtual model, which perfectly agrees with the one measured on the fabricated device. Besides morphological, electrical and thermal characterizations, this work includes reliability tests in static and dynamic modes.

Age- and gender-dependent values of skeletal muscle mass in healthy children and adolescents.

Science.gov (United States)

Webber, Colin E; Barr, Ronald D

2012-03-01

Skeletal muscle mass (SMM) can be extracted from whole-body scans obtained by X-ray-based dual-photon absorptiometry (DXA). There is a need to establish expected age-dependent values for children and adolescents. Appendicular lean tissue mass (ALM) was extracted from whole-body DXA scans in 140 healthy children and adolescents (68 females and 72 males). Whole-body SMM was calculated from ALM using equations developed by Kim et al. (Am J Clin Nutr 84:1014-1020, 2006). Age-dependent patterns of increase in SMM were derived by fitting SMM values to equations that consisted of the sum of two logistic expressions, one accounting for SMM changes during growth and the other for SMM changes during puberty. Normal ranges were defined so that 95% of the SMM values were included. The reproducibility of SMM measurements was obtained from whole-body DXA scans repeated on three occasions in each of a separate group of 32 normal children with repositioning between scans. Normal ranges are presented as equations describing the age-dependent pattern of increase in SMM as well as population standard deviations that increased steadily with age. For 15 children below age 10, SMM reproducibility (95% CI) was 149 g (119-199 g) while for 17 children and adolescents over age 10, reproducibility was 170 g (138-223 g). DXA-based measurements of SMM in children and adolescents are reproducible and can be expressed in terms of age-dependent Z scores.

Laser-induced novel patterns: As smart strain actuators for new-age dental implant surfaces

Energy Technology Data Exchange (ETDEWEB)

Celen, Serap, E-mail: serap.celen@ege.edu.tr [Ege University, Faculty of Engineering, Mechanical Engineering Department, Izmir, 35100 (Turkey); Oezden, Hueseyin [Ege University, Faculty of Engineering, Mechanical Engineering Department, Izmir, 35100 (Turkey)

2012-12-15

Highlights: Black-Right-Pointing-Pointer It is time for that paradigm shift and for an exploration of novel surfaces. Black-Right-Pointing-Pointer We developed novel 3D smart surfaces as strain actuators by nanosecond laser pulse energies. Black-Right-Pointing-Pointer We analyzed these smart surface morphologies using FEM. Black-Right-Pointing-Pointer We estimated their internal stiffness values which play a great role on stress shielding effect. Black-Right-Pointing-Pointer We gave the optimum operation parameters. - Abstract: Surface morphologies of titanium implants are of crucial importance for long-term mechanical adaptation for following implantation. One major problem is the stress shielding effect which originates from the mismatch of the bone and the implant elasticity. It is time for a paradigm shift and for an exploration of novel smart surfaces to prevent this problem. Several surface treatment methods have traditionally been used to modify the surface morphology of titanium dental implants. The laser micro-machining can be considered as a unique and promising, non-contact, no media, contamination free, and flexible treatment method for modifying surface properties of materials in the biomedical industry. The aim of the present study is two folds; to develop novel 3D smart surfaces which can be acted as strain actuators by nanosecond laser pulse energies and irradiation strategies. And analyze these smart surface morphologies using finite element methods in order to estimate their internal stiffness values which play a great role on stress shielding effect. Novel 3D smart strain actuators were prepared using an ytterbium fiber laser ({lambda} = 1060 nm) with 200-250 ns pulse durations on commercial pure titanium dental implant material specimen surfaces and optimum operation parameters were suggested.

Effects of extreme-duration heavy load carriage on neuromuscular function and locomotion: a military-based study.

Directory of Open Access Journals (Sweden)

Jordane G Grenier

Full Text Available Trekking and military missions generally consist of carrying heavy loads for extreme durations. These factors have been separately shown to be sources of neuromuscular (NM fatigue and locomotor alterations. However, the question of their combined effects remains unresolved, and addressing this issue required a representative context.The aim was to investigate the effects of extreme-duration heavy load carriage on NM function and walking characteristics.Ten experienced infantrymen performed a 21-h simulated military mission (SMM in a middle-mountain environment with equipment weighing ∼27 kg during battles and ∼43 kg during marches. NM function was evaluated for knee extensors (KE and plantar flexors (PF pre- and immediately post-SMM using isometric maximal voluntary contraction (MVC measurement, neural electrical stimulation and surface EMG. The twitch-interpolation method was used to assess central fatigue. Peripheral changes were examined by stimulating the muscle in the relaxed state. The energy cost, mechanical work and spatio-temporal pattern of walking were also evaluated pre-/post-SMM on an instrumented treadmill in three equipment conditions: Sportswear, Battle and March.After the SMM, MVC declined by -10.2±3.6% for KE (P<0.01 and -10.7±16.1% for PF (P = 0.06. The origin of fatigue was essentially peripheral for both muscle groups. A trend toward low-frequency fatigue was detected for KE (5.5%, P = 0.08. These moderate NM alterations were concomitant with a large increase in perceived fatigue from pre- (rating of 8.3±2.2 to post-SMM (15.9±2.1, P<0.01. The SMM-related fatigue did not alter walking energetics or mechanics, and the different equipment carried on the treadmill did not interact with this fatigue either.this study reports the first data on physiological and biomechanical consequences of extreme-duration heavy load carriage. Unexpectedly, NM function alterations due to the 21-h SMM were moderate and did not

Effects of extreme-duration heavy load carriage on neuromuscular function and locomotion: a military-based study.

Science.gov (United States)

Grenier, Jordane G; Millet, Guillaume Y; Peyrot, Nicolas; Samozino, Pierre; Oullion, Roger; Messonnier, Laurent; Morin, Jean-Benoît

2012-01-01

Trekking and military missions generally consist of carrying heavy loads for extreme durations. These factors have been separately shown to be sources of neuromuscular (NM) fatigue and locomotor alterations. However, the question of their combined effects remains unresolved, and addressing this issue required a representative context. The aim was to investigate the effects of extreme-duration heavy load carriage on NM function and walking characteristics. Ten experienced infantrymen performed a 21-h simulated military mission (SMM) in a middle-mountain environment with equipment weighing ∼27 kg during battles and ∼43 kg during marches. NM function was evaluated for knee extensors (KE) and plantar flexors (PF) pre- and immediately post-SMM using isometric maximal voluntary contraction (MVC) measurement, neural electrical stimulation and surface EMG. The twitch-interpolation method was used to assess central fatigue. Peripheral changes were examined by stimulating the muscle in the relaxed state. The energy cost, mechanical work and spatio-temporal pattern of walking were also evaluated pre-/post-SMM on an instrumented treadmill in three equipment conditions: Sportswear, Battle and March. After the SMM, MVC declined by -10.2±3.6% for KE (P<0.01) and -10.7±16.1% for PF (P = 0.06). The origin of fatigue was essentially peripheral for both muscle groups. A trend toward low-frequency fatigue was detected for KE (5.5%, P = 0.08). These moderate NM alterations were concomitant with a large increase in perceived fatigue from pre- (rating of 8.3±2.2) to post-SMM (15.9±2.1, P<0.01). The SMM-related fatigue did not alter walking energetics or mechanics, and the different equipment carried on the treadmill did not interact with this fatigue either. this study reports the first data on physiological and biomechanical consequences of extreme-duration heavy load carriage. Unexpectedly, NM function alterations due to the 21-h SMM were moderate and did not alter

Bifunctional Zn(II)Ln(III) dinuclear complexes combining field induced SMM behavior and luminescence: enhanced NIR lanthanide emission by 9-anthracene carboxylate bridging ligands.

Science.gov (United States)

Palacios, María A; Titos-Padilla, Silvia; Ruiz, José; Herrera, Juan Manuel; Pope, Simon J A; Brechin, Euan K; Colacio, Enrique

2014-02-03

There were new dinuclear Zn(II)-Ln(III) complexes of general formulas [Zn(μ-L)(μ-OAc)Ln(NO3)2] (Ln(III) = Tb (1), Dy (2), Er (3), and Yb (4)), [Zn(μ-L)(μ-NO3)Er(NO3)2] (5), [Zn(H2O)(μ-L)Nd(NO3)3]·2CH3OH (6), [Zn(μ-L)(μ-9-An)Ln(NO3)2]·2CH3CN (Ln(III) = Tb (7), Dy (8), Er (9), Yb(10)), [Zn(μ-L)(μ-9-An)Yb(9-An)(NO3)3]·3CH3CN (11), [Zn(μ-L)(μ-9-An)Nd(9-An)(NO3)3]·2CH3CN·3H2O (12), and [Zn(μ-L)(μ-9-An)Nd(CH3OH)2(NO3)]ClO4·2CH3OH (13) prepared from the reaction of the compartmental ligand N,N',N″-trimethyl-N,N″-bis(2-hydroxy-3-methoxy-5-methylbenzyl)diethylenetriamine (H2L), with ZnX2·nH2O (X = NO3(-) or OAc(-)) salts, Ln(NO3)3·nH2O, and, in some instances, 9-anthracenecarboxylate anion (9-An). In all these complexes, the Zn(II) ions invariably occupy the internal N3O2 site whereas the Ln(III) ions show preference for the O4 external site, giving rise to a Zn(μ-diphenoxo)Ln bridging fragment. Depending on the Zn(II) salt and solvent used in the reaction, a third bridge can connect the Zn(II) and Ln(III) metal ions, giving rise to triple-bridged diphenoxoacetate in complexes 1-4, diphenoxonitrate in complex 5, and diphenoxo(9-anthracenecarboxylate) in complexes 8-13. Dy(III) and Er(III) complexes 2, 8 and 3, 5, respectively, exhibit field induced single molecule magnet (SMM) behavior, with Ueff values ranging from 11.7 (3) to 41(2) K. Additionally, the solid-state photophysical properties of these complexes are presented showing that ligand L(2-) is able to sensitize Tb(III)- and Dy(III)-based luminescence in the visible region through an energy transfer process (antenna effect). The efficiency of this process is much lower when NIR emitters such as Er(III), Nd(III), and Yb(III) are considered. When the luminophore 9-anthracene carboxylate is incorporated into these complexes, the NIR luminescence is enhanced which proves the efficiency of this bridging ligand to act as antenna group. Complexes 2, 3, 5, and 8 can be considered as dual materials

Low skeletal muscle mass is a predictive factor for chemotherapy dose-limiting toxicity in patients with locally advanced head and neck cancer.

Science.gov (United States)

Wendrich, Anne W; Swartz, Justin E; Bril, Sandra I; Wegner, Inge; de Graeff, Alexander; Smid, Ernst J; de Bree, Remco; Pothen, Ajit J

2017-08-01

Low skeletal muscle mass (SMM) or sarcopenia is emerging as an adverse prognostic factor for chemotherapy dose-limiting toxicity (CLDT) and survival in cancer patients. Our aim was to determine the impact of low SMM on CDLT in patients with locally advanced head and neck squamous cell carcinoma (LA-HNSCC) treated with primary radiochemotherapy (RCT). Consecutive patients diagnosed with LA-HNSCC and treated with primary RCT between 2007 and 2011 in our center were included. Clinical variables were retrospectively retrieved and SMM was measured at the level of the third cervical vertebra using pre-treatment head and neck CT-scans. After determining a cut-off value for low SMM, multivariate analysis was performed to identify prognostic factors for CDLT. Of 112 patients included, 30.4% experienced CDLT. The optimal cut-off value for low SMM as a predictor of CDLT was ≤43.2cm 2 /m 2 . Using this cut-off, 54.5% patients had low SMM. Patients with low SMM experienced CDLT more frequently than patients with normal SMM (44.3% vs. 13.7%, pSMM, p=0.044). At multivariate analysis, low SMM was independently inversely associated with CDLT (OR 0.93, 95%CI: 0.88-0.98). Patients experiencing CDLT had a lower overall survival than patients who did not (mean 36.6vs. 54.2months, p=0.038). Low SMM is an independent risk factor for CDLT in LA-HNSCC patients treated with primary RCT. Pre-therapeutic estimation of SMM using routine CT-scans of the head and neck region may identify patients at risk of CDLT. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Kinetics of Myosin Light Chain Kinase Activation of Smooth Muscle Myosin in an In Vitro Model System

OpenAIRE

Hong, Feng; Facemyer, Kevin C.; Carter, Michael S.; Jackson, Del R.; Haldeman, Brian D.; Ruana, Nick; Sutherland, Cindy; Walsh, Michael P.; Cremo, Christine R.; Baker, Josh E.

2013-01-01

During activation of smooth muscle contraction, one myosin light chain kinase (MLCK) molecule rapidly phosphorylates many smooth muscle myosin (SMM) molecules, suggesting that muscle activation rates are influenced by the kinetics of MLCK-SMM interactions. To determine the rate-limiting step underlying activation of SMM by MLCK, we measured the kinetics of calcium-calmodulin (Ca2+-CaM)-MLCK-mediated SMM phosphorylation and the corresponding initiation of SMM-based F-actin motility in an in vi...

Micromachining of inertial confinement fusion targets

International Nuclear Information System (INIS)

Gobby, P.L.; Salzer, L.J.; Day, R.D.

1996-01-01

Many experiments conducted on today's largest inertial confinement fusion drive lasers require target components with sub-millimeter dimensions, precisions of a micron or less and surface finishes measured in nanometers. For metal and plastic, techniques using direct machining with diamond tools have been developed that yield the desired parts. New techniques that will be discussed include the quick-flip locator, a magnetically held kinematic mount that has allowed the direct machining of millimeter-sized beryllium hemishells whose inside and outside surface are concentric to within 0.25 micron, and an electronic version of a tracer lathe which has produced precise azimuthal variations of less than a micron

Severe Maternal or Near Miss Morbidity: Implications for Public Health Surveillance and Clinical Audit.

Science.gov (United States)

Kuklina, Elena V; Goodman, David A

2018-06-01

This chapter reviews the historical development of indicators to identify severe maternal morbidity/maternal near miss (SMM/MNM), and their use for public health surveillance, research, and clinical audit. While there has been progress toward identifying standard definitions for SMM/MNM within countries, there remain inconsistencies in the definition of SMM/MNM indicators and their application between countries. Using these indicators to screen for events that then trigger a clinical audit may both under identify select SMM/MNM (false negative)and over identify select SMM/MNM (false positive). Thus, indicators which support the efficient identification of SMM/MNM for the purpose of facility-based clinical audits are still needed.

Measurement of flat samples with rough surfaces by Magnetic Adaptive Testing

Czech Academy of Sciences Publication Activity Database

Tomáš, Ivan; Kadlecová, Jana; Vértesy, G.

2012-01-01

Roč. 48, č. 4 (2012), s. 1441-1444 ISSN 0018-9464. [Conference on Soft Magnetic Materials (SMM20) /20./. Kos Island, 18.09.2011-22.09.2011] R&D Projects: GA ČR GA101/09/1323 Institutional research plan: CEZ:AV0Z10100520 Keywords : magnetic contact * magnetic adaptive testing * magnetically open samples * magnetic NDE Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.422, year: 2012

Picosecond laser machined designed patterns with anti-ice effect

NARCIS (Netherlands)

Del Cerro, D.A.; Römer, G.R.B.E.; Huis in 't Veld, A.J.

2010-01-01

Micromachining using ultra short laser pulses (USLP) has evolved over the past years as a versatile tool for introducing functional features in surfaces at a micrometric and even at a sub wavelength scale. Being able to control the surface topography at this level provides a method to change the

Calculation of surface acoustic waves in a multilayered piezoelectric structure

International Nuclear Information System (INIS)

Zhang Zuwei; Wen Zhiyu; Hu Jing

2013-01-01

The propagation properties of the surface acoustic waves (SAWs) in a ZnO—SiO 2 —Si multilayered piezoelectric structure are calculated by using the recursive asymptotic method. The phase velocities and the electromechanical coupling coefficients for the Rayleigh wave and the Love wave in the different ZnO—SiO 2 —Si structures are calculated and analyzed. The Love mode wave is found to be predominantly generated since the c-axis of the ZnO film is generally perpendicular to the substrate. In order to prove the calculated results, a Love mode SAW device based on the ZnO—SiO 2 —Si multilayered structure is fabricated by micromachining, and its frequency responses are detected. The experimental results are found to be mainly consistent with the calculated ones, except for the slightly larger velocities induced by the residual stresses produced in the fabrication process of the films. The deviation of the experimental results from the calculated ones is reduced by thermal annealing. (semiconductor physics)

Scintimammography with 99mTc-MIBI and magnetic resonance imaging in the evaluation of breast cancer

International Nuclear Information System (INIS)

Bagni, B.; Franceschetto, A.; Casolo, A.; De Santis, M.; Bagni, I.; Pansini, F.; Di Leo, C.

2003-01-01

This study was performed to evaluate the sensitivity and specificity of technetium-99m methoxyisobutylisonitrile ( 99m Tc-MIBI) scintimammography (SMM) and contrast-enhanced magnetic resonance imaging (MRI) in patients with breast masses, using the histological findings as the gold standard. Forty-five consecutive patients with a breast lesion, detected by self-examination, physical examination or screening mammography, underwent SMM and MRI. In 38 cases (84.5%), the histopathology was malignant; the breast cancers ranged from 3 to 100 mm in diameter (mean 22 mm). In the overall patient group, MRI showed a slightly higher sensitivity than SMM (92% vs 84%), but SMM showed a better specificity: 71% vs 42%. The accuracy was 82% and 84% for SMM and MRI respectively. To evaluate the influence of lesion size on the results, patients with lesions ≤20 mm and ≤15 mm were examined. In patients with lesions ≤20 mm, the sensitivity of SMM and MRI decreased to 64% and 82% respectively, while SMM again displayed considerably better specificity: 83% vs 50% for MRI. The accuracy of SMM and MRI was 64% and 82% respectively. In patients with lesions ≤15 mm, SMM again showed better specificity (75% vs 50%), while MRI displayed better sensitivity and accuracy (sensitivity, 81% vs 62%; accuracy, 75% vs 65%). In this study the specificity of SMM in patients with breast lesions was thus superior to that of MRI. The combination of SMM and MRI may be used in those patients with equivocal findings at mammography and ultrasound to reduce the number of unnecessary surgical biopsies. (orig.)