Detection Delay Time Research Articles

90 nm급 텅스텐 폴리사이드 게이트 식각공정에서 식각종말점의 안정화에 관한 연구

The device makers want to make higher density chips on the wafer through scale-down. The change of WSix/poly-Si gate film thickness is one of the key issues under 100 nm device structure. As a new device etching process is applied, end point detection(EPD) time delay was occurred in DPS+ poly chamber of Applied Materials. This is a barrier of device shrink because EPD time delay made physical damage on the surface of gate oxide. To investigate the EPD time delay, the experimental test combined with OES(Optical Emission Spectroscopy) and SEM(Scanning Electron Microscopy) was performed using patterned wafers. As a result, a EPD delay time is reduced by a new chamber seasoning and a new wavelength line through plasma scan. Applying a new wavelength of 252 nm makes it successful to call corrected EPD in WSix/poly-Si stack-down gate etching in the DPS+ poly chamber for the current and next generation devices.

Using cost based FMEA to enhance reliability and serviceability

Failure Modes and Effects Analysis (FMEA) is a design tool that mitigates risks during the design phase before they occur. Although many industries use the current FMEA technique, it has many limitations and problems. Risk is measured in terms of Risk Priority Number (RPN) that is a product of occurrence, severity, and detection difficulty. Measuring severity and detection difficulty is very subjective and with no universal scale. RPN is also a product of ordinal variables, which is not meaningful as a proper measure. This paper addresses these shortcomings and introduces a new methodology, Life Cost-Based FMEA, which measures risk in terms of cost. Life Cost-Based FMEA is useful for comparing and selecting design alternatives that can reduce the overall life cycle cost of a particular system. Next, a Monte Carlo simulation is applied to the Cost-Based FMEA to account for the uncertainties in: detection time, fixing time, occurrence, delay time, down time, and model complex scenarios. A case study of a large scale particle accelerator shows the advantages of the proposed approach in predicting life cycle failure cost, measuring risk and planning preventive, scheduled maintenance and ultimately improving up-time.

Fluorescence Intensity and Lifetime Distribution Analysis: Toward Higher Accuracy in Fluorescence Fluctuation Spectroscopy

Fluorescence fluctuation methods such as fluorescence correlation spectroscopy and fluorescence intensity distribution analysis (FIDA) have proven to be versatile tools for studying molecular interactions with single molecule sensitivity. Another well-known fluorescence technique is the measurement of the fluorescence lifetime. Here, we introduce a method that combines the benefits of both FIDA and fluorescence lifetime analysis. It is based on fitting the two-dimensional histogram of the number of photons detected in counting time intervals of given width and the sum of excitation to detection delay times of these photons. Referred to as fluorescence intensity and lifetime distribution analysis (FILDA), the technique distinguishes fluorescence species on the basis of both their specific molecular brightness and the lifetime of the excited state and is also able to determine absolute fluorophore concentrations. The combined information yielded by FILDA results in significantly increased accuracy compared to that of FIDA or fluorescence lifetime analysis alone. In this paper, the theory of FILDA is elaborated and applied to both simulated and experimental data. The outstanding power of this technique in resolving different species is shown by quantifying the binding of calmodulin to a peptide ligand, thus indicating the potential for application of FILDA to similar problems in the life sciences.

Evaluation of Power History during Power Burst Experiments in TRACY by Combination of Gamma-Ray and Thermal Neutron Detectors

A combination method using γ-ray and thermal neutron detectors was newly applied to the accurate evaluation of power histories during reactivity-initiated power burst experiments in the Transient Experiment Critical Facility (TRACY). During an initial power burst, the power history was determined using a fast response γ-ray ionization chamber, which was used because of its ability to exactly trace the power history within a short duration of the initial burst. After the initial burst, a micro fission chamber containing highly enriched uranium was used for the determination of the power history because the γ-ray ionization chamber could not be applied due to the contribution of delayed γrays from fission products. By the present method, the power histories were evaluated for the experiments in the range of 1.50 to 2.93$ of the reactivity insertion. It was found that the peak power and integrated power as determined by the previous method using only the micro fission chamber were underestimated to be 40% and 30% in maximum, respectively, in comparison with the results from the present evaluation. The numerical simulation performed by using the Monte Carlo method indicated that the underestimation could be comprehended by considering the time delay of thermal neutron detection of the fission chamber, which arose from the flight-time of neutrons from the TRACY core to the fission chamber.

Simulation by Monte Carlo Method of Power Varying with Time Detected by Fission Chamber in TRACY Water-Reflected System

Numerical simulation of power varying with time detected by fission chamber was performed using the continuous-energy Monte Carlo code MCNP4B to comprehend time delay of neutron detection in power burst experiments arranged for systems incorporating water reflector as well as devoid of reflector in the Transient Experiment Critical Facility (TRACY). The simulation indicated that power generation in core during an initial power burst was detected by fission chamber earlier in a water-reflected than in a non-reflected system. The difference is ascribed to the water reflector surrounding the core tank functioning as shield against neutrons traveling toward the concrete walls and floor of the building structure, to lower the probability of detection by fission chamber of the neutrons proceeding from walls and floor, to result in earlier termination of neutron detection, and hence shorter lapse of time between neutron emission from core and detection. The difference between water-reflected and non-reflected systems in the delay time, however, is quite small—within about 1 ms. The difference is even smaller when expressed in terms of inverse period, and can be considered to affect little the evaluation of feedback reactivity based on the inverse period.

Pressure and gas composition effects on the operation of the pulsed flame photometric detector

AbstractThe effect of pressure and hydrogen/oxygen ratio of a burning gas mixture on pulsed flame emission time‐dependence was investigated in the range of 0.1–5 atm using a specially designed pulsed flame photometric detector (PFPD). We studied the pressure and gas composition effect on the pulsed flame delayed light emission of sulfur, phosphorus, and nitrogen‐containing organic compounds. The optimal pressure conditions for nitrogen detection, intensity, and emission time delay was found to be 0.4 bar, at which the detection sensitivity could be improved by a factor of 2. For phosphorus, the optimal pressure obtained was 1.3 bar with 40% sensitivity improvement (compared with 1 bar). In the case of sulfur detection, two emission maxima were obtained, at 1.1 and 0.6 bar, at H/O ratio of 5. Increasing the H/O ratio resulted in the appearance of only one peak at 1 bar, and enhancement of the sensitivity by a factor of 2.4 at H/O ratio of 10.3. From the analytical point of view, we found that emission intensity is practically unchanged by the pressure and the H/O ratio for all three elements investigated in the range of 0.8–1.1 bar and H/O of 5–6. Thus, in addition to excellent sensitivity and improved selectivity, the PFPD can be applied under a variety of atmospheric pressure conditions in field environmental applications.

Analytical studies on the hotspot temperature of cable-in-conduit conductors

This paper describes an analytical study to review the hotspot temperature design criterion of the cable-in-conduit conductors for the ITER magnet system. The ITER magnet system uses three kinds of cable-in-conduit conductors for the Toroidal Field (TF) coils, the Central Solenoid (CS) and the Poloidal Field (PF) coils. The amount of copper in the superconducting cable has been defined by using the classical hotspot temperature design criterion that is based on the adiabatic condition. In the current design, ITER superconducting cables include a large number of pure copper strands to satisfy the classical criterion. However, the temperature and stress in the conduit and insulations after quench can be simulated with the quench simulation program and stress analysis program using the latest analysis tools. This analysis shows that the strand temperature is dominated by the conduction along strands and the heat capacity of other conductor materials and coolant. The hotspot temperature depends strongly on the delay time for quench detection. This analysis provides an estimation of the delay times for quench detection. The thermal and stress analysis can provide the maximum allowable temperature after quench by determination of a failure or a functional disorder condition of the jacket material and turn insulation. In conclusion, it is found that the current density of the cable space can be increased, by reducing the extra copper strand, thereby, allowing a reduction of the coil radial build.

Time Delay of Thermal Neutron Detection during Power Burst in TRACY

Time delay of thermal neutron detection at a micro fission chamber has been experimentally confirmed during an initial power burst caused by reactivity addition in the Transient Experiment Critical Facility (TRACY). In the experiment, the power was measured by using a fast response γ-ray ionization chamber, which was newly designed exclusively for the TRACY experiment, in addition to the fission chamber. As results of the experiment, the transient power measured by the fission chamber was observed about 4 ms later than that by the γ-ray chamber during the power increasing, and then the delay time expanded after the power peak. The time delay must be taken into account to evaluate accurately the transient power. To comprehend the observed time delay in detail, time-dependent analyses were performed using the MCNP4B code. In the analyses, time response of neutron detection at the fission chamber was calculated and used for the simulation of the transient power measured by the fission chamber. From results of the analyses, it was confirmed that the simulated power well agreed with the measured power and the observed time delay was caused from the thermalization of neutrons emitted at the TRACY core and the following flight to the fission chamber.

Analytical Studies on Hotspot Temperature of Cable-in-conduit Conductors

This paper describes an analytical study to review the hotspot temperature design criteria of the cable-in-conduit conductors for the ITER magnet system. The ITER magnet system uses three kinds of cable-in-conduit conductors for the Toroidal Filed (TF) coils, the Central Solenoid (CS) and the Poloidal Filed (PF) coils. The amount of copper in the superconducting cable has been defined by using the classical hotspot temperature design criteria that is based on the adiabatic condition. In the current design, ITER superconducting cables include a large amount of pure copper strands to satisfy the classical criteria. However, temperature and stress in the conduit and insulations after quench can be simulated with the quench simulation program and stress analysis program using the latest analysis tools. This analysis shows that the strand temperature is dominated by the conduction along strands and the heat capacity of other conductor materials and coolant. The hotspot temperature depends strongly on the delay time for quench detection. This analysis provides an estimation of delay times for quench detection. The thermal and stress analysis can provide the maximum allowable temperature after quench by determination of a failure or a functional disorder condition of the jacket material and turn insulation. In conclusion, it is found that the current density of the cable space can be increased, by reducing the extra copper strand, thereby, allowing a reduction of the coil radial build.

Time Delay of Thermal Neutron Detection during Power Burst in TRACY.

Time delay of thermal neutron detection at a micro fission chamber has been experimentally confirmed during an initial power burst caused by reactivity addition in the Transient Experiment Critical Facility (TRACY). In the experiment, the power was measured by using a fast response γ-ray ionization chamber, which was newly designed exclusively for the TRACY experiment, in addition to the fission chamber. As results of the experiment, the transient power measured by the fission chamber was observed about 4 ms later than that by the γ-ray chamber during the power increasing, and then the delay time expanded after the power peak. The time delay must be taken into account to evaluate accurately the transient power. To comprehend the observed time delay in detail, time-dependent analyses were performed using the MCNP4B code. In the analyses, time response of neutron detection at the fission chamber was calculated and used for the simulation of the transient power measured by the fission chamber. From results of the analyses, it was confirmed that the simulated power well agreed with the measured power and the observed time delay was caused from the thermalization of neutrons emitted at the TRACY core and the following flight to the fission chamber.

Sensitized and Quenched Phosphorescence as a Detection Mode in Capillary Electrophoresis

The potential of sensitized and quenched phosphorescence of biacetyl as an optical detection mode in capillary electrophoresis (CE), complementary to absorption and fluorescence detection, was explored. From 24 naphthalenesulfonates (NS) that were studied in batch experiments, 5 NS were used as test compounds in CE. The technique is based on the intense phosphorescence emission of biacetyl (present as a constituent of the CE buffer) at room temperature in deoxygenated liquid solutions. A simple device, based on purging with nitrogen gas, was developed to meet this deoxygenation requirement in CE. A standard liquid chromatography luminescence detector, provided with a pulsed xenon light source, was used for detection. In view of the phosphoresence lifetime of biacetyl (70 μs under present solution conditions), the background caused by scattered excitation light could be readily suppressed by using a delay time for detection. Both phosphorescence modes can be applied at a 0.02 M biacetyl concentration, though in the quenched mode a biacetyl concentration of 0.05 M yields better results. From the five test analytes considered, three show sensitized phosphorescence and two dynamically quenched phosphorescence. Though various experimental parameters still have to be optimized further, the results are quite encouraging: under stacking conditions (pt = 768 mbar·s), detection limits ranged from 5 × 10(-)(8) to 4 × 10(-)(7) M.

Use of fiber interface direct mass spectrometry for the determination of volatile flavor release from model food systems.

Described in this paper is a fiber interface direct headspace mass spectrometric system for the real-time measurement of flavor release. The system was optimized for the detection of the garlic aroma volatile, diallyl disulfide, from water. Parameters investigated included interface temperature, flow rate through the fiber, flow rate through the sample vessel, and sample stir rate. The delay time for detection of sample after introduction into the sample vessel was determined as 43 s. The system proved to be reliable and robust with no loss in sensitivity or contamination of the mass spectrometer over a 6 month period. The technique was applied to a homologous series of aliphatic alcohols from C(2) to C(7). Results showed that as polarity decreased with increasing chain length the release of volatile into the headspace was faster and gave a higher maximum intensity. Release of the garlic aroma volatile from different commercial mayonnaise products clearly showed a decrease in the release of diallyl disulfide as fat content increased. These results demonstrate the potential of using this technique as a tool for understanding the complex interactions that occur between flavor compounds and the bulk food matrix.

Robust Gauge Control for Hot Finishing Mills

A new gauge control system for hot finishing mills has been developed to distribute the mill motor power of each stand. The new system has the following features : (a) Interstand exit gauge is calculated based on the law of mass flow constancy using the exit thickness gauge. (b) The design strategy of the new system are to cope with a detection time delay, and to simplify the controller to easily tune during actual implementation. (c) The H∞, controller with two degrees of freedom is designed to obtain high responses of the reference and disturbance. The performance of the controller is evaluated by numerical simulation. The effectiveness of the new system has been shown by application in an actual plant.

Comparative Investigations of Algorithms for the Detection of Breaths in Newborns with Disturbed Respiratory Signals

The correct detection of the beginning of inspiration and expiration in the respiratory signals is an essential prerequisite for accurate lung function testing in newborns. Five algorithms for breath detection using pneumotachographically measured flow and volume signals were investigated with regard to the error rate. To compare and to evaluate the reliability of these algorithms 12 minimally and 12 severely disturbed flow and volume signals from spontaneously breathing newborns were used. With the exception of an algorithm based on Walsh-transformed signals, all algorithms work reliably (error rate <1.1%) if disturbances are minimal. In severely disturbed signals there is a great difference between the algorithms. The most robust algorithm tested (trigger of the flow signal with an additional plausibility check of the recognized breath) resulted in an error rate of <3.4%. Not all algorithms tested are suitable for real-time applications because they differ considerably in delay time for breath detection.

Cathodoluminescence of ZnSe(Bi):Al crystals

The cathodoluminescence (CL) in ZnSe crystals annealed at T=1200 K in a Bi melt containing an aluminum impurity is investigated. The spectra are recorded for different excitation levels, temperatures, and detection delay times t0. As t0 is increased, the intensity of the orange band at λmax=630 nm (1.968 eV) in the CL spectrum decreases in comparison to the intensity of the dominant yellow-green band at λmax=550 nm (2.254 eV), whose half-width increases in the temperature range 6–120 K and then decreases as the temperature increases further. It is shown that such behavior of the yellow-green band is caused by the competition between two processes: recombination of donor-acceptor pairs and of free electrons with holes trapped on acceptors. The former mechanism is dominant at low temperatures, and the latter mechanism is dominant at high temperatures. At T∼120 mK the contributions of the two mechanisms to the luminescence are comparable. The resultant structureless band then achieves its greatest half-width, which is dictated by the interaction of the recombining charge carriers with longitudinal-optical and longitudinal-acoustic phonons and with the free-electron plasma. The mean number of longitudinal-optical phonons emitted per photon is determined mainly by their interaction with holes trapped on deep acceptors in the form of Al atoms replacing Se. The donor in the pair under consideration is an interstitial Al atom.

Enhanced Detection Criteria in Implantable Cardioverter-Defibrillators to Avoid Inappropriate Therapy

The aim of this prospective study was to evaluate the efficacy and safety of enhanced detection criteria, stability and sudden onset, for ventricular tachycardia (VT) in the therapy of implantable cardioverter-defibrillators (ICDs). These detection enhancements ensure a high specificity in detecting VT, thereby avoiding inappropriate therapy delivery due to supraventricular tachycardia. However, delayed sensing or even undersensing of VT may lead to a problematic, even fatal, outcome. In our study, the stability detection enhancement was programmed to discriminate atrial fibrillation (AF) in 84 of 124 patients with implanted ICDs and the sudden-onset detection enhancement in 47 of the 124 patients to discriminate sinus tachycardia. Using these enhancements in 124 patients with third-generation ICDs, 13 patients (11%) had inappropriate therapy during 20 months of follow-up. AF caused shock delivery in 6 patients (5%) and antitachycardia pacing in 4 patients, atrial flutter triggered shock therapy in 1 patient, and sinus tachycardia caused shock delivery in 2 patients. In 3 of the 13 patients inappropriate therapy recurred despite reprogramming the detection enhancements. The stability parameter of 241 spontaneous VT episodes as measured by the devices was 8 ± 7 msec. Only 10 (4%) VTs had a stability parameter >25 msec. In 46 patients a combination of both detection enhancements, stability and/or sudden onset, were programmed. The use of detection enhancements proved safe and no patient had suffered negative side effects due to prolonged detection time or therapy delay. Inappropriate shock delivery due to AF, a major complication in ICD therapy, was reduced to 5% of patients. The use of the stability enhancement is recommended for patients with intermittent or chronic AF. Selected patients profit from programming both the stability and sudden onset criteria. (Am J Cardiol 1996;78(suppl 5A):42–50)

Resonantly excited photoluminescence spectra of porous silicon.

Resonantly excited low-temperature photoluminescence spectra of porous silicon (por-Si) samples show a steplike structure with at least four phonon-related steps. For different n- and p-doped por-Si, we examine this phonon structure in spectra taken both during laser excitation and after different detection delay times following laser shutoff, ranging from 10 \ensuremath{\mu}s to 1.2 ms. The luminescence efficiency decreases and the phonon structure becomes more pronounced when lowering the excitation energy or when increasing the delay time between the detection window and the excitation. This observation suggests two separate luminescence mechanisms in por-Si: a very efficient one that is usually observed (even at room temperature) when exciting at higher energies (\ensuremath{\approxeq}3 eV), and one that shows a phonon structure and can be seen only at low temperatures and when the efficient mechanism is suppressed by excitation at energies lower than 2 eV.

Observer-based multivariable flatness control of a cold rolling mill

The synthesis methodology developed by Kimura (1985) based on the design theory of output regulators essentially due to Wonham (1974) has been applied successfully to the flatness control system for a 6-high cold rolling mill. The system has the following remarkable features. 1. (1) The structure of the controller is simple. This makes it easy to tune the control system. 2. (2) The controller copes well with the detection time delay, and thus high performance is obtained even at a low rolling speed. 3. (3) The flatness error caused by the rolling force variation in mill acceleration and deceleration time would be kept to a minimum by the function to adjust roll bending force using the signal of rolling force.

Observer-Based Multivariable Flatness Control of the Cold Rolling Mill

The synthesis methodology developed by Kimura(Kimura, 1985) based on the design theory of output regulators essentially due to Wonham(Wonham, 1974) has been applied successfully to the flatness control system for the 6-high cold rolling mill. Our system has the following remarkable features.(1) The structure of the controller is simple. This makes it easy to tune the control system.(2) The controller copes well with the detection time delay, and thus high performance is obtained even at a low rolling speed.(3) The flatness error caused by the rolling force variation in mill acceleration and decceleration time would be kept to a minimum by the function to adjust roll bending force using the signal of rolling force.

On Construction of Sequential Procedures for Detection of a Change-Point of Parameters in Stochastic Dynamic Systems

The problem of detection of stepwise change of parameters in liner stochastic systems specified by stochastic differential and stochastic difference equations is considered. The parameters of the system before the disruption time and after it are assumed to be known. New sequential procedures of disruption detection based on the cumulative sums method are proposed. The main difference of these procedures from known ones consists in the fact that statistics which are used in the algorithm are calculated not by separate observations but by a set of observations of random volume. The other difference is connected with quantization of statistics in cumulative sums algorithm which enables to obtain analytically the chief characteristics: the mean time between false alarms and the mean delay time of disruption detection. It is established that the mean delay time increases logarithmically with the growth of mean time between false alarms.