bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synergistic effects in hybrid free radical/cationic photopolymerizations
Authors: Crivello James V. 
Published: July 2007

AbstractMultifunctional alkyl glycidyl ether and oxetane monomers are usually deemed to be poorly reactive and are consequently of limited use for high speed photocuring applications. However, these monomers can be made to undergo exceedingly rapid exothermic photopolymerization when combined with a multifunctional acrylate monomer and a corresponding free radical photoinitiator. Under optimum UV irradiation conditions, these hybrid photopolymerizations take place rapidly and substantially without an induction period. A mechanism was proposed on the basis of thermal acceleration of the cationic ring‐opening polymerizations induced by the fast exothermic free radical acrylate photopolymerization. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3759–3769, 2007
Synthesis of grafted poly(p‐phenyleneethynylene) with energy donor–acceptor architecture via atom transfer radical polymerization: Towards nonaggregating and hole‐facilitating light‐emitting material
Authors: Pu Kan‐Yi , Chen Yi , Qi Xiao‐Ying , Qin Chun‐Yang , Chen Qing‐Quan , Wang Hong‐Yu , Deng Yun , Fan Qu‐Li , Huang Yan‐Qin , Liu Shu‐Juan , Wei Wei , Peng Bo , Huang Wei 
Published: July 2007

AbstractIn this contribution, we demonstrate a new effective methodology for constructing highly efficient and durable poly(p‐phenyleneethynylene) (PPE) containing emissive material with nonaggregating and hole‐facilitating properties through the introduction of hole‐transporting blocks into the PPE system as the grafting coils as well as building the energy donor–acceptor architecture between the grafting coils and the PPE backbone. Poly(2‐(carbazol‐9‐yl)ethyl methacrylate) (PCzEMA), herein, is chosen as the hole‐transporting blocks, and incorporated into the PPE system as the grafting coils via atom transfer radical polymerization. The chemical structure of the resultant copolymer, PPE‐g‐PCzEMA, was characterized by NMR and gel permeation chromatography, showing that the desirable copolymer was obtained with the narrow polydispersity. The increased thermal stability of PPE‐g‐PCzEMA was confirmed by thermogravimetric analysis and differential scanning calorimetry along with its macroinitiator. The optoelectronic properties of this copolymer were studied in detail by ultraviolet‐visible absorption, photoluminescence emission and excitation spectra, and cyclic voltammogram (CV). The results indicate that PPE‐g‐PCzEMA exhibits the solid‐state luminescent property dominated by individual lumophores, and also the energy transfer process from the PCzEMA blocks to the PPE backbone with a relatively higher energy transfer efficiency in the solid‐state compared to that of the solution state. Additionally, the hole‐injection property is greatly facilitated due to the presence of PCzEMA, as confirmed by CV profiles. All these data indicate that PPE‐g‐PCzEMA is a good candidate for use in optoelectronic devices. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3776–3787, 2007
Interaction of ACTH synthetic fragments with rat adrenal cortex membranes
Authors: Kovalitskaya Yulia A. , Zolotarev Yury A. , Kolobov Alexander A. , Sadovnikov Vladimir B. , Yurovsky Vladimir V. , Navolotskaya Elena V. 
Published: July 2007

AbstractSynthetic peptide, corresponding to the amino acid sequence 11–24 of human adrenocorticotropic hormone (ACTH), was labeled with tritium (specific activity of 22 Ci/mmol). [3H]ACTH (11–24) was found to bind to rat adrenal cortex membranes with high affinity and specificity (Kd = 1.8 ± 0.1 nM). Twenty nine fragments of ACTH (11–24) have been synthesized and their ability to inhibit the specific binding of [3H]ACTH (11–24) to adrenocortical membranes has been investigated. Unlabeled fragment ACTH 15–18 (KKRR) was found to replace in a concentration‐dependent manner [3H]ACTH (11–24) in the receptor–ligand complex (Ki = 2.3 ± 0.2 nM). ACTH (15–18) was labeled with tritium (specific activity of 20 Ci/mmol). [3H]ACTH (15–18) was found to bind to rat adrenal cortex membranes with high affinity (Kd = 2.1 ± 0.1 nM). The specific binding of [3H]ACTH (15–18) was inhibited by unlabeled ACTH (11–24) (Ki = 2.2 ± 0.1 nM). ACTH (15–18) at the concentration range of 1–1000 nM did not affect the adenylate cyclase activity in adrenocortical membranes. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd.
Assimilating GPS radio occultation measurements with two‐dimensional bending angle observation operators
Authors: Healy S. B. , Eyre J. R. , Hamrud M. , Thépaut J.‐N. 
Published: July 2007

AbstractFour‐dimensional variational (4D‐Var) assimilation forecast impact experiments were conducted with CHAMP radio occultation measurements from 1st June to 31st July 2004. The CHAMP bending angles were assimilated with one‐dimensional (1D) and two‐dimensional (2D) bending angle observation operators, enabling the potential benefits of the latter to be investigated. Two computationally affordable 2D bending angle observation operators were considered. The first can be viewed as a straightforward generalisation of the 1D operator. The second is based on a fourth order Runge–Kutta solution of the differential equations defining the ray‐path through the refracting atmosphere.It is demonstrated that the computational cost of the 2D bending angle operators is not prohibitive and that they improve the root‐mean‐square of the observed minus background (O‐B) bending angle departures by around 5% in the lower‐troposphere of the northern and southern hemispheres. The O‐B distributions in the tropical lower‐troposphere are biased low, but the first‐guess departure quality control procedure removes ∼2–3% of the observations and this reduces the bias by around 20%. The assimilation of the CHAMP measurements with both the 1D and 2D operators improves the analysis and forecast fit to radiosonde temperature measurements in the southern hemisphere on the 300, 200, 100 and 50 hPa levels, over the day‐1 to day‐5 forecast range. The forecast scores in the lower‐troposphere for geopotential height and relative humidity are generally neutral, but there is a small improvement in the anomaly correlation of the 500 hPa geopotential height field in the southern hemisphere, over the day‐1 to day‐2 forecast range. However, there are no clear, statistically significant differences between the 1D and 2D experiments for this two‐month period. Copyright © 2007 Royal Meteorological Society
Activation energies and the arrhenius equation
Authors: Jensen Finn 
Published: July 2007

AbstractThis paper examines the current use of the Arrhenius equation and the activation energies associated with integrated circuits. A short introduction to the Arrhenius equation is given and it is shown how activation energies may be computed from experimental data.The paper next addresses the following basic question: is it reasonable to extrapolate from high‐temperature laboratory life‐tests down to use conditions using the Arrhenius equation? The paper shows that the answer to this question in general must be an emphatic no. It is not the validity of the Arrhenius equation as such that is questioned, but its indiscriminate use by reliability practitioners across the electronics industry.This is not a scientific paper, and no ‘proofs’ are given. The discussion is based on ‘typical’ integrated circuits using published data on the temperature dependence of the hazard rate of such circuits. The paper serves as a warning against thinking that ‘well established practices’ are necessarily scientifically sound.
Effectiveness of formal reliability programmes
Authors: O'Connor Patrick D. T. 
Published: July 2007

AbstractThe development of complex yet highly reliable systems is one of the greatest technical and management challenges of our time. Because such systems are often developed and manufactured for official agencies, and to their specifications, it is necessary to impose controls that will ensure achievement of a performance parameter which is neither predictable nor measurable during development. Since failure is a stochastic process, statistical and actuarial techniques have been developed, but these have been emphasized too much in official reliability programmes.
Electrostatic discharge: mechanisms, protection techniques and effects on integrated circuit reliability
Authors: Avery L. R. 
Published: July 2007

AbstractElectrostatic discharge (ESD) was once considered a problem only for unprotected, insulated‐gate field‐effect transistors, but the ever shrinking geometries of all semiconductor devices have made them vulnerable to this phenomenon. ESD models and on‐chip device protection techniques are reviewed, together with current evidence concerning latent defects and their effect on device reliability. A brief discussion on the importance of ESD controls in the assembly environment is also included, with an emphasis on realistic cost‐effective measures. Finally, the impact of continued scaling on ESD vulnerability and protection structure limitations, are examined.
Reliability in communications satellites
Authors: Mancino Vincent J. , Slusark Walter J. 
Published: July 2007

AbstractThe reliability of complex communications satellites is discussed as well as the elements necessary to ensure the specified life. Some of these elements are novel to commercial communications satellites, and generally are found only in military satellites having very exacting reliability requirements. Also treated are some of the changes that have been implemented within the last decade to enhance reliability and increase the life of space communications satellites.
Traffic signal equipment procurement based on cost of ownership and community cost
Authors: Blanks H. S. 
Published: July 2007

AbstractThe principles of cost of ownership have been applied to the development of a system of traffic signal equipment procurement in which the failure cost includes the cost to the community arising from increased accident rate and traffic disruption due to malfunctioning equipment.The paper first summarizes some of the principles and guidelines of LCC procurement. It then gives the cost‐of‐ownership equation which has been developed for the comparative tender assessment of traffic signal equipment. It explains the categorization of signal malfunction modes according to their hazard‐creation and traffic‐disruption severities, providing a matrix of 5 × 5 hazard/disruption categories, and gives the derivation of the corresponding community cost rates. It discusses the proposed method of implementation of the system, including a warranty/guarantee plan intended to overcome the problem of MTBF prediction inaccuracy and to provide incentive for MTBF improvement. The paper concludes with a discussion of the savings which can be achieved through use of the system and of its cost effectiveness.The system was developed for the Department of Main Roads, New South Wales.
Vlsi yield management and prediction
Authors: Ferris‐Prabhu A. V. 
Published: July 2007

AbstractThis paper presents a practical method for managing and predicting the yield of VLSI products, in a manner that will provide insight, with a minimum of mathematical complexity, into the sensitivity of the yield to the different quantities which limit it. The yield equation is cast into a form which makes evident the contributions of its constituent terms and the formulation is developed in a manner that permits its ready application to yield characterization, diagnostics and prediction. An illustrative example is presented that integrates the concepts and methods developed.
In defence of numerical techniquesgl
Authors: Benz Glen E. 
Published: July 2007

AbstractThe purpose of this article is to say a few kind words for numerical techniques, which have become the object of some undeserved criticism. Probability information is part of decision‐making, be it intuitive or analytical. In this age of the personal computer we do not have to go to great lengths to quantify this information, so why not do it? The failure to rescue hostages in Iran is a dramatic example that reliance on intuition can have bad results. On the side of numerical techniques, three examples of successful and practical applications are described. It is concluded that ‘the numbers game’ contributes worthwhile support to decision‐making and should continue to co‐exist with ‘shirt‐sleeve’ efforts to improve products and policies.
Stress test development on a processor system
Authors: Venn Keith 
Published: July 2007

AbstractThermal cycling and vibration tests were carried out on an intermediate processor family of machines to investigate the benefits of controlled stressing as a means of screening manufacturing defects, and to provide data for return on investment calculations. Major items to be considered were(a) low cost of test programme(b) complete unit to be stressed (complex interactions between subassemblies)(c) relatively low expected failure rate(d) limited field reporting.Stress techniques used were mild thermal cycling and pseudo‐random vibration.Analysis of field data from the stressed population showed an overall reliability improvement of 24 per cent during the first 30 days of customer operation.
A new approach to reliability prediction is needed
Authors: Florescu Radu A. 
Published: July 2007

AbstractThis paper starts from the main objections regarding MIL‐HDBK‐217 and the BELLCORE method for reliability prediction, objections asserting that these methods are approximate, complicated and unconvincing. To support these assertions, and by applying techniques specific to reliability theory, the author has developed a reliability model which is plausible for certain elements of technical systems. The existence of such a model, which in practice is useless because the failure rate expression is too complicated, proves clearly the inefficiency of classical methods.
Electrostatic pulse breakdown in nmos devices
Authors: Amerasekera E. A. , Campbell D. S. 
Published: July 2007

AbstractThe electrostatic discharge (ESD) sensitivity of small dimension n‐channel metal oxide semiconductor (NMOS) field effect transistors (FETs) has been investigated. NMOS FETs of varying dimensions and a constant gate oxide thickness of 400® were each subjected to a single ESD voltage pulse of between 50 and 250V at temperatures between 25 and 200°C. Over 4000 devices were used, all resident on a single 3 inch silicon wafer. The object of the experiment was to determine the dependence of device ESD sensitivity on temperature, voltage and device dimensions as well as to investigate the mechanisms that cause oxide breakdown as a result of ESD damage.No temperature dependence of device ESD sensitivity was observed within the range of the experiment. A significant voltage dependence was observed, with degradation accounting for over 80 per cent of devices at 250V. A cumulative ESD effect was observed, whereby the degradation of device performance was found to increase with the number of applied pulses. Analysis of the breakdown characteristics revealed that the cause of damage was oxide breakdown. Application of the ESD pulse appears to lead to oxide breakdown through impact ionization within the oxide, the very short duration of the pulse not being favourable to processes involving electron trapping unless these traps are already present in the oxide.
Use of liquid‐crystal thermography for defect location on semiconductor devices
Authors: Beck F. 
Published: July 2007

AbstractHot‐spot detection, a thermographic technique with liquid crystals, marks hot regions on a surface. The use of this highly sensitive method in failure analysis of integrated devices allows the detection of points on a chip where electrical power is converted into heat. Points such as these are often indicative of a fault, e.g. a leakage path or an increase in transfer resistance. The technique is based on the birefringence of a liquid crystal (LC) in the anisotropic state below the clearing temperature (Tc). Above this temperature, in the isotropic state, the effect disappears. The device under test, covered with the LC, is observed below the clearing point in polarized light with a crossed polarizer and analyser. Owing to the optical rotation of the anisotropic LC the image is bright. At hot spots the LC changes to the isotropic state and a dark spot is produced. A decisive factor for the thermal resolution of the technique is the precise temperature adjustment of the tested device. With lateral resolution of some tenths of a μ‐m it is still possible to detect current paths with dissipation of 50 to 500μW. The sensitivity can be increased further. Square‐wave pulses of selectable voltage, frequency and duty cycle are used to drive the test item. Four examples from failure analysis demonstrate the possibilities of using hot‐spot thermography, the main features of which are speed, uncomplicated handling and depth of information.
Cathode ray tube bleed resistor reliability—a case study
Authors: Hale Peter , Mactaggart Iain , Shaw Martin 
Published: July 2007

AbstractThis paper describes, and gives a mathematical analysis of, the performance of two makes of CRT bleed resistors which exhibit markedly different characteristics under heat soak conditions. By examining the observed resistance changes with temperature, and relating these to the Arrhenius equation, the reaction activation energies can be determined.Further analysis of the power consumption characteristics of the resistors leads to the establishment of resistance‐time curves for both makes of resistor. These indicate very different conclusions than might otherwise have been drawn from initial test data. Finally the Monte Carlo' simulation technique is used to determine the most likely survival characteristics in a field situation, and a quantitative assessment of the reliability of CRTs using these bleed resistors is given.The construction of the resistor body is common to both makes and comprises a resistor substrate enclosed within an overcoat which is in turn encapsulated in epoxy. One make (type A) is a glass thick film structure, whereas the other is a polymer thick film system.
Optimum replacement of deteriorating and inadequate equipment
Authors: Blanks H. S. , Tordon M. J. 
Published: July 2007

AbstractDetermination of the optimum equipment replacement policy and time is of great economic importance. After a brief survey of the models which have been used for decision making, the paper looks at methods for detecting and quantifying growth of failure frequency (peril rate) in repairable equipment. It examines the trend detection methods of Laplace and Mann when the peril rate varies as a power of equipment age and also applies them to some actual field failure data. An economic model is developed, based on total discounted future cost and providing for ongoing future technological growth. The cost comprises not only the conventional cost of ownership, but also the shortfall between an equipment's achieved benefit and that which would be achieved by an ideal equipment in the same demand environment. The inclusion of this shortfall, called incapacity cost', enables the replacement decision to be based not only on the deterioration of equipment but also on its performance inadequacy and on the availability of technological improvement in present and future challengers.The formulation of the cost model is such that for both a single‐replacement finite planning horizon and an infinite horizon the total discounted future cost is readily computed for a range of alternative replacement times and the optimum replacement programme thereby determined. The sensitivity of total cost to the replacement times and the sensitivity of the optimum times to the variability of assumed input data are easily examined.The application of the model to traffic signal equipment is described. In this application the total cost is shared between the nominal owner of the equipment and the community.
Economic models and process quality control
Authors: Montgomery Douglas C. , Storer Robert H. 
Published: July 2007

AbstractQuality is an important business strategy in the economic and technological environment of today. To achieve high product quality, it is important to take explicit account of the cost of quality, and to use this cost as another management control. A new direction for achieving a cost‐effective quality management system is to design statistical process controls so as to directly incorporate quality costs. This paper discusses the major approaches to the economic design of statistical process controls, and compares several different model formulations. The practical implication of these techniques is stressed. In particular, two economic models of the chart are presented: a full economic model requiring a user‐specified process and nine cost parameters, and a semi‐economic model using five user‐specified parameters. Both of these could serve as approaches to reducing the total cost of process control. Because of its simplicity in application the semi‐economic model should gain greater acceptance by practitioners for the design of process control techniques.
Simplified markov techniques for some stand‐by redundant systems
Authors: Hamilton R. , Bazovsky Sr I. , 
Published: July 2007

AbstractThe simplified techniques presented in this paper are the result of a study* of specific stand‐by system configurations comprised of combinations of two different types of non‐repairable operating parts. Failed parts of either type are replaced with stand‐by parts of just one of the two types. All parts have constant failure rates. The simplified transition probability diagram technique centres on the transition probability diagram and is here applied to one of seven system configurations of the original study. To validate the transition probability diagram technique an expanded Markov flow graph is used. Both of these simplified techniques offer advantages over other, existing techniques. A single, general mean time to failure (MTTF) equation is obtained for all the configurations analysed. The developed techniques were used in the analysis of an actual electrical system design project.
Functional screens for electronic reliability
Authors: Ganter William A. 
Published: July 2007

AbstractThis paper describes a class of reliability screens for use in the manufacturing process of electronic products which are directly related to the funcationality of the product being produced. The field reliability that was attained from using functional screening on an example product is presented. Because of the exceptionally low failure occurrence now possible in today's products, some simple alternative reliability monitoring statistics based on the binomial are suggested. Implications of this improved reliability on the effectiveness of screening methods is discussed, and the notion of field failures as screening escapes is introduced. Then some reasons to experiment with functional stress screens in place of a total reliance on the more traditional environmental stress screens are presented. Finally, the characteristics of functional screens are presented. Careful experimentation using appropriate statistical analysis in developing and comparing screening approaches is emphasized throughout this paper.