bluuebunny/crossref_metadata_2025 huggingface dataset:
CUSTODY DISPUTES INVOLVING ALLEGATIONS OF DOMESTIC VIOLENCE: TOWARD A DIFFERENTIATED APPROACH TO PARENTING PLANS
Authors: Jaffe Peter G. , Johnston Janet R. , Crooks Claire V. , Bala Nicholas
Published: May 2008

Premised on the understanding that domestic violence is a broad concept that encompasses a wide range of behaviors from isolated events to a pattern of emotional, physical, and sexual abuse that controls the victim, this article addresses the need for a differentiated approach to developing parenting plans after separation when domestic violence is alleged. A method of assessing risk by screening for thepotency,pattern, andprimary perpetratorof the violence is proposed as a foundation for generating hypotheses about the type of and potential for future violence as well as parental functioning. This kind of differential screening for risk in cases where domestic violence is alleged provides preliminary guidance in identifying parenting arrangements that are appropriate for the specific child and family and, if confirmed by a more in‐depth assessment, may be the basis for a long‐term plan. A series of parenting plans are proposed, with criteria and guidelines for usage depending upon this differential screening, ranging from highly restricted access arrangements (no contact with perpetrators of family violence and supervised access or monitored exchange) to relatively unrestricted ones (parallel parenting) and even co‐parenting. Implications for practice are considered within the context of available resources.
QUESTIONS ABOUT FAMILY COURT DOMESTIC VIOLENCE SCREENING AND ASSESSMENT
Authors: Frederick Loretta
Published: May 2008

Increasingly, family courts are seeking ways to focus limited resources on cases that require the most intervention, tailor court responses and dispute methods to each case, and account for the real differences among domestic violence cases. One of the means to that end may be the triaging or screening of cases. This article raises a number of questions about screening and urges that they be addressed by courts and communities that are considering whether and how to design a screening protocol. Issues include: How should we define domestic violence for the purposes of screening? Who should carry out the screening? How can we maximize the likelihood that we will fully assess the context of the violence in each case? How should we assess the risks or dangers inherent in the parties’ situation? How should a screening effort account for changing circumstances as a case proceeds through the courts? How can information gathered in a screening effort improperly impact subsequent decisions of the court?
DIVORCE AND THE FAMILY COURT: WHAT CAN BE DONE ABOUT DOMESTIC VIOLENCE?
Authors: Ellis Desmond
Published: May 2008

Approximately 50% of couples who have separated report being victims of violence and/or emotional abuse by their former intimate partners. Family courts can make an important contribution toward reducing the number of intimate partners who report being victims of domestic violence and abuse during and following their participation in divorce proceedings in three ways. First, increase opportunities for participation in nonadversarial procedures. Second, implement mandatory assessment/screening for domestic violence using field‐tested instruments that link subscores on sets of items (e.g., control motivated violence, conflict instigated violence/abuse, substance abuse associated violence/abuse) with appropriate community‐based treatments and/or resources. Third, educate family court judges, lawyers, mediators, and other court personnel in the dynamics of domestic violence generally, as well as the dynamics associated with separation/divorce.
Solid phase testing in the HLA laboratory: implications for organ allocation
Authors: Eckels D. D.
Published: May 2008

Preface

This piece was originally requested as a white paper from the Scientific and Clinical Affairs Committee of the American Society for Histocompatibility and Immunogenetics (ASHI), of which the author was then Chairman. Upon review by the ASHI Board of Directors and the Editors of their journal, it was considered too controversial for publication. It is intended to be provocative and controversial; it is not intended as a review of the literature. Though written with a decided ‘American point of view’, it is of importance that the issues facing US transplantation and laboratory testing efforts are shared to varying degrees by the international community, and who, unlike some of their American cousins, may be able to tolerate a spirited discussion. Sadly, we sometimes forget that dissent from dogma can be fun!
Older immigrants’ experiences of their life situation in the context of receiving public care in Sweden
Authors: Hovde Boel , Hallberg Ingalill R. , Edberg Anna‐Karin
Published: May 2008

Objectives.  The aim of this study was to illuminate older immigrants’ experience of their life situation in the context of receiving public care in Sweden.

Background.  To meet the varying needs from the growing number of older immigrants, more knowledge about the experience of their life situation, health, illness and family ties is needed, especially in the context of receiving public health care and service.

Methods.  Data were collected through interviews with sixteen immigrants aged 65 years and older, originally from nine different countries, living in Southern Sweden and receiving continuous care and service. The texts were analysed using qualitative content analysis.

Results.  The overall impression from the texts was that the informants expressed a debt of gratitude to Swedish society. Their experience could be understood as – being burdened with health complaints; experiencing painful losses; wanting to manage by oneself and feeling exposed and deserted.

Conclusions.  The results show that older immigrants are vulnerable when receiving public care. This was related to previous life events, cultural differences as well as communication difficulties. When planning for and providing care for older immigrants, it is important to be aware of their exposed situation and to acknowledge their life history and family context.
Multiprofessional collaboration promoting home care clients' personal resources: perspectives of older clients
Authors: Eloranta Sini , Arve Seija , Routasalo Pirkko
Published: May 2008

Home care can be decisive in supporting older people in the home environment. However, one professional in home care cannot take the whole responsibility for promotion alone; on the contrary multiprofessional collaboration is needed. The aim of the study is to describe the experiences of multiprofessional collaboration in promoting personal resources among older home care clients (75+ years) in Finland. The data were collected by unstructured interviews with 21 older home care clients. Their mean age was 83.5 years, ranging from 75 to 91, with 17 female and four male participants. Inductive content analysis was used to analyze the data. The interviewees described the work of professionals from four perspectives: expertise, communication, decision‐making and responsibility. Multiprofessional collaboration promoted the personal resources of interviewees with physical, psychological and social support. This study showed that the professionals worked as being expert‐oriented: in the multiprofessional collaboration, each expert took care of his/her own part of the client’s situation. This included the risk,, that the client’s overall situations remained uncharted. However, the client’s overall situation is a very important aspect when professionals suppport older people living in their own homes as long as possible. This study revealed the need for developing collaboration skills between social and health care professionals so that the staffs serve the needs of aged clients better together.
Practice development in aged care nursing of older people: the perspective of ageing and spiritual care
Authors: MacKinlay Elizabeth
Published: May 2008

This third paper on older people nursing and spirituality moves beyond the literature reviewed in the two previous papers, exploring directions for the practice and continuing research in this field. Issues of chronic illness challenge nurses working with older people to focus on continuing health promotion and opportunities for spiritual promotion of resilience and transcendence. The changes from monocultural to multicultural societies challenge nurses to know how to provide culturally and faith appropriate care. The extension of palliative care to the needs of those growing older and dying is noted as an important area for developing spiritual care. It is asserted that spiritual assessment forms a basis for the provision of spiritual care for all of these themes. Ethical perspectives of older people nursing must be carefully addressed as frail and vulnerable older people struggle with issues of compromised autonomy. Further research should focus on spirituality as seen through the eyes of older people and examine the interface between nurses and patients, where the relationship becomes the guiding basis for practice. Education in nursing courses and through continuing programmes of education is needed to ensure adequate understanding of spirituality in the nursing role.
Sociosexual Orientation and Sexual Behavior in Mexican Adults
Authors: Díaz‐Loving Rolando , Rodríguez Georgina García
Published: May 2008

Sociosexual orientation includes individual differences in sexual attitudes and behaviors, in relation to the extent in which an individual could be sexually active without affective bonds and commitment. Sociosexuality is related to sexual behavior and can speak to the differences between men and women in how they express their sexuality (Simpson & Gangestad, 1991; Hebl & Casi, 1995; Ostovich & Sabini, 2004). This study explores sociosexual orientation and sexual behavior in Mexican adults, in order to identify differences in sociosexual orientation related to biological sex and relationship status. It also assesses the relationship between sociosexual orientation and sexual behavior and to predict sexual behavior from sociosexual orientation. The sample was composed of 209 Mexican adults between 19 and 61 years of age. Thirty‐seven percent were male, and 63% were female. Participants answered a standardized Spanish version of the Sociosexual Orientation Inventory (Simpson & Gangestad, 1991) and a Sexual Behavior Inventory developed for the present project (García Rodríguez, 2007). In general, there is great variability in the frequency of each of the sexual behaviors assessed and in the total number of sexual partners. Moreover, participants perceive themselves restricted in their sexual attitudes and behaviors. Men are more permissive and less restricted in attitudes and behaviors than women, and individuals who are dating informally have a higher behavioral sociosexual orientation than those who are living with their partner. Additionally, the higher sociosexuality, the more frequent sexual practices are and the higher the number of sexual partners. Finally, sociosexuality predicts the frequency of sexual practices and the number of lifetime sexual partners.
Self‐Handicapping: On the Self‐Perpetuating Nature of Defensive Behavior
Authors: Rhodewalt Frederick
Published: May 2008

The term self‐handicapping was introduced by Jones and Berglas (1978) to refer to the creation of barriers to successful performance for the purpose of controlling attributions about the self. In the event of failure, attributions to lack of ability are diminished or discounted because of the handicap and, in the event of success, attributions to ability are enhanced or augmented because of the handicap. This article reviews over 25 years of research on self‐handicapping. A process model is presented in which individual differences in goals and concerns dynamically interact with situational threats to elicit self‐handicapping behavior which produces consequences that perpetuate the use of the behavior in future situations.
Effect of Laser Preheating the Workpiece on Micro end Milling of Metals
Authors: Jeon Yongho , Pfefferkorn Frank
Published: May 2008

Micro end milling is a fast and direct method of creating net-shaped functional microparts, micromolds, and prototypes. However, the small flexural stiffness, strength, and hardness of the tool limit the efficiency of machining. It is not expected that a new material with increased hardness and yield strength will be developed in the near future that significantly improves the durability for tools manufactured with diameters in the tens to hundreds of microns. To enable a significant increase in performance and productivity requires higher spindle speeds and increased chiploads. However, an increase in chipload is inhibited by the small flexural stiffness and strength of the tools: a direct result of the tool diameter. Laser-assisted micro end milling has the potential to increase the chipload and productivity by locally reducing the workpiece material’s yield strength at the cutting location. This study examines the effect of laser preheating on micro end milling of 6061-T6 aluminum and 1018 steel. Two-flute, 300μmdia, carbide end mills are used to cut 100μm deep slots at a spindle speed of 40,000rpm. The laser power and chipload are varied to show their effect on cutting forces, specific cutting energy, burr formation, surface finish, and temperature. The results are compared to the average material removal temperature given by predictions made from a heat transfer model of the workpiece undergoing laser preheating. Results indicate that chipload and productivity can be significantly increased during dry machining of 6061-T6 aluminum and 1018 steel by localized preheating of the workpiece.
Analysis of the Sawing Process With Abrasive Circular Saw Blades
Authors: Mizuno Masahiro , Iyama Toshirou , Zhang Bi
Published: May 2008

This study simulates the sawing process with an abrasive circular saw blade and analyzes the generation of cutoff surfaces in the sawing process with the consideration of the blade deflection caused by the asymmetric wear of the blade outer edge. The analysis is built on the previous work of Matsui (1956, J. Jpn. Soc. Precis. Eng., 22, pp. 477–481) who presented an analytical formula for cutting force acting on a conical cutting edge. In this paper, the Matsui formula is modified to take into account the “size effect” of grinding and used to calculate the grinding force acting on the blade surface. A differential equation is constructed, and the related numerical solutions are provided to describe the blade deflection behavior in the sawing process. The study then discusses the influences of the “size effect,” workpiece length, workpiece speed and feed rate, as well as cutting edge density on sawing accuracies. Also discussed are workpiece speed and cutting edge density on the maximum deviation of the cutoff surface.
Multiple Fault Diagnosis Method in Multistation Assembly Processes Using Orthogonal Diagonalization Analysis
Authors: Kong Zhenyu , Ceglarek Dariusz , Huang Wenzhen
Published: May 2008

Dimensional control has a significant impact on overall product quality and performance of large and complex multistation assembly systems. To date, the identification of process-related faults that cause large variations of key product characteristics (KPCs) remains one of the most critical research topics in dimensional control. This paper proposes a new approach for multiple fault diagnosis in a multistation assembly process by integrating multivariate statistical analysis with engineering models. The proposed method is based on the following steps: (i) modeling of fault patterns obtained using state space representation of process and product information that explicitly represents the relationship between process-related error sources denoted by key control characteristics (KCCs) and KPCs, and (ii) orthogonal diagonalization of measurement data using principal component analysis (PCA) to project measurement data onto the axes of an affine space formed by the predetermined fault patterns. Orthogonal diagonalization allows estimating the statistical significance of the root cause of the identified fault. A case study of fault diagnosis for a multistation assembly process illustrates and validates the proposed methodology.
Modeling and Verification of an Innovative Active Pneumatic Vibration Isolation System
Authors: Porumamilla H. , Kelkar A. G. , Vogel J. M.
Published: May 2008

This paper presents a novel concept in active pneumatic vibration isolation. The novelty in the concept is in utilizing an air-spring-orifice-accumulator combination to vary the natural frequency as well as inject damping into the system per requirement, thereby eliminating the need for a hydraulic cylinder or a magnetorheological damper. This continuously variable natural frequency and damping (CVNFD) technology is aimed at achieving active vibration isolation. For analysis purposes, a particular application in the form of pneumatic seat suspension for off-road vehicles is chosen. A mathematical model representing the system is derived rigorously from inertial dynamics and first principles in thermodynamics. Empirical corelations are also used to include nonlinearities such as friction that cannot be accounted for in the thermodynamic equations. An exhaustive computational study is undertaken to help understand the physics of the system. The computational study clearly depicts the CVNFD capability of the vibration isolation system. An experimental test rig is built to experimentally validate analytical and simulation modeling of the system. Experimental verification corroborated the variable natural frequency and damping characteristic of the system observed through computational simulations.
Virtual Five-Axis Flank Milling of Jet Engine Impellers—Part II: Feed Rate Optimization of Five-Axis Flank Milling
Authors: Ferry W. B. , Altintas Y.
Published: May 2008

This paper presents process optimization for the five-axis flank milling of jet engine impellers based on the mechanics model explained in Part I. The process is optimized by varying the feed automatically as the tool-workpiece engagements, i.e., the process, vary along the tool path. The feed is adjusted by limiting feed-dependent peak outputs to a set of user-defined constraints. The constraints are the tool shank bending stress, tool deflection, maximum chip load (to avoid edge chipping), and the torque limit of the machine. The linear and angular feeds of the tool are optimized by two different methods—a multiconstraint based virtual adaptive control of the process and a nonlinear root-finding algorithm. The five-axis milling process is simulated in a virtual environment, and the resulting process outputs are stored at each position along the tool path. The process is recursively fitted to a first-order process with a time-varying gain and a fixed time constant, and a simple proportional-integral controller is adaptively tuned to operate the machine at threshold levels by manipulating the feed rate. As an alternative to the virtual adaptive process control, the feed rate is optimized by a nonlinear root-finding algorithm. The virtual cutting process is modeled as a black box function of feed and the optimum feed is solved for iteratively, respecting tool stress, tool deflection, torque, and chip load constraints. Both methods are shown to produce almost identical optimized feed rate profiles for the roughing tool path discussed in Paper I. The new feed rate profiles are shown to considerably reduce the cycle time of the impeller while avoiding process faults that may damage the part or the machine.
A Combined Finite Element and Finite Difference Analysis of Cold Flat Rolling
Authors: Gudur P. P. , Dixit U. S.
Published: May 2008

The finite element analysis of cold flat rolling has been carried out by a number of researchers using updated Lagrangian and flow formulations. The major difficulty in the flow formulation is the estimation of hydrostatic stress accurately. In this work, a mixed pressure-velocity finite element flow formulation is used in obtaining the velocity field during the rolling process. The hydrostatic stress is obtained by solving the momentum equations using a finite difference method. The values of Levy–Mises coefficient and strain-rate components required in the finite difference equations are obtained as a function of spatial coordinates using a radial basis function neural network modeling. The proposed method is compared with a mixed pressure-velocity finite element method and experimental results available in the literature. It is observed that the proposed method provides a better agreement with the experimental results.
A Mathematical Model of Driver Steering Control Including Neuromuscular Dynamics
Authors: Pick Andrew J. , Cole David J.
Published: May 2008

A mathematical driver model is introduced in order to explain the driver steering behavior observed during successive double lane-change maneuvers. The model consists of a linear quadratic regulator path-following controller coupled to a neuromuscular system (NMS). The NMS generates the steering wheel angle demanded by the path-following controller. The model demonstrates that reflex action and muscle cocontraction improve the steer angle control and thus increase the path-following accuracy. Muscle cocontraction does not have the destabilizing effect of reflex action, but there is an energy cost. A cost function is used to calculate optimum values of cocontraction that are similar to those observed in the experiments. The observed reduction in cocontraction with experience of the vehicle is explained by the driver learning to predict the steering torque feedback. The observed robustness of the path-following control to unexpected changes in steering torque feedback arises from the reflex action and cocontraction stiffness of the NMS. The findings contribute to the understanding of driver-vehicle dynamic interaction. Further work is planned to improve the model; the aim is to enable the optimum design of steering feedback early in the vehicle development process.
On the Practical Stability of Incorporating Integral Compensation Into the Low-and-High Gain Control for a Class of Systems With Norm-Type Input Saturation
Authors: Peng Shou-Tao
Published: May 2008

This paper studies the practical stability of incorporating integral compensation into the original low-and-high gain feedback law. The motivation for the incorporation is for achieving output regulation in the presence of constant disturbances without the use of a very large high-gain parameter required in the original approach. Due to numerical accuracy, the employment of very large high-gain parameters to eliminate steady-state error has the potential for inducing undesirable chattering effect on the control signal. A set of linear matrix inequalities is formulated in this study to obtain the related design parameters, by which the incorporation can achieve both the practical stabilization and asymptotic output regulation in the presence of input saturation and constant disturbances. Furthermore, the saturation of the control input can be shown to vanish in finite time during the process of regulation. Numerical examples are given to demonstrate the effectiveness of the proposed approach.
Whirling-Beam Self-Tuning Vibration Absorber
Authors: Ivers Douglas , Wilson Robert , Margolis Donald
Published: May 2008

A classic tuned vibration absorber (TVA) is a device that, when attached to a structure, will greatly reduce the motion of the attachment at a specific excitation frequency. When a fixed frequency input is present, a TVA can be manufactured for the specific frequency input. When the input frequency changes during the course of operation, then an active adaptive TVA can be used where sensors, signal conditioning, and power are provided so that the tuned frequency can be varied over some range. A self-tuning vibration absorber (STVA) is a device that uses energy from the vibrating structure to produce some physical motion that changes the tuned frequency of the device. Through proper design, the tuned frequency will change in the appropriate direction and then stop changing when the tuned frequency matches the input frequency. This paper addresses the physics of one realization of a STVA and shows both analytical and experimental results.
Model Following Sliding Mode Control Based on Uncertainty and Disturbance Estimator
Authors: Talole S. E. , Phadke S. B.
Published: May 2008

A new design of sliding mode control based on an uncertainty and disturbance estimator (UDE) is given. The control proposed does not require the knowledge of bounds of uncertainties and disturbances and is continuous. Thus, two main difficulties in the design of sliding mode control are overcome. Furthermore, the method of UDE is extended to plants having significant uncertainty in the control input matrix and subjected to disturbances that nonlinearly depend on states.
Influence of the microstructure on steel hardening in pulsed plasma nitriding
Authors: Ochoa E. A. , Figueroa C. A.
Published: May 2008

The plasma technologies are widely used in metal surface engineering processes. Basically, these treatments improve the mechanical, tribological, and chemical properties of the material such as wear resistance, hardness, fatigue resistance, friction, and corrosion resistance. In this work, a comprehensive study of the influence of the microstructure on hardness of AISI P20 steel treated at different temperatures and times by pulsed plasma nitriding is reported. The processes were done by using a pulsed plasma industrial system. The samples were characterized by nano-indentation (hardness), x-ray diffraction (XRD), scanning electron microscopy (SEM), and x-ray dispersion spectroscopy (EDS). At lower treatment temperatures (360 °C), a high density of small lamellar precipitates, constituted by more ε-Fe2–3N phase than γ′-Fe4N phase, is formed. At intermediate treatment temperatures (480 °C), big lamellar precipitates, constituted by more γ′-Fe4N phase than ε-Fe2−3N phase, are formed at grain boundary. At higher treatment temperatures (520 °C), the nitrided layer does not contain lamellar precipitates and it is only constituted by α-Fe phase saturated in nitrogen. Hardness depends on size, shape, and distribution of precipitates and crystalline phases (microstructure). The higher hardness values are obtained when more and smaller lamellar precipitates are presented and constituted by more ε-Fe2−3N phase.
Effect of gas mixing ratio on etch behavior of ZrO2 thin films in BCl3∕He inductively coupled plasma
Authors: Kim Mansu , Min Nam-Ki , Yun Sun Jin , Lee Hyun Woo , Efremov Alexander , Kwon Kwang-Ho
Published: May 2008

This article reports a study carried out on a model-based analysis of the etch mechanism for ZrO2 thin films in a BCl3∕He inductively coupled plasma. It was found that an increase in the He mixing ratio at a fixed gas pressure and input power results in an increase in the ZrO2 etch rate, which changes from 36to57nm∕min for 0–83% He. Langmuir probe diagnostics and zero-dimensional plasma modeling indicated that both plasma parameters and active species kinetics were noticeably influenced by the initial composition of the BCl3∕He mixture, resulting in the nonmonotonic or nonlinear behaviors of species densities. Using the model-based analysis of etch kinetics, it was demonstrated that the behavior of the ZrO2 etch rate corresponds to the ion-flux-limited etch regime of the ion-assisted chemical reaction.
Multilayer transparent electrode consisting of silver alloy layer and metal oxide layers for organic luminescent electronic display device
Authors: Koike Katsuhiko , Fukuda Shin
Published: May 2008

A transparent electrode for an organic luminescent electronic display (OLED) requires higher transmittance and higher electric conductivity to reduce the power consumption, in order that more of the current injected into the display results in luminescence. The authors made transparent conductive multilayer coatings including layers of silver alloy with 1wt% of palladium (Pd) and 1wt% of copper (Cu) (APC) and transparent metal oxide thin film layers for the transparent electrode of an OLED. Indium tin oxide (ITO) and zinc aluminum oxide (AZO) were used as the transparent metal oxides. A multilayer transparent electrode consisting of ITO/APC/ITO and one of AZO/APC/AZO prepared by dc magnetron sputtering achieved transmittance of more than 80% in the wavelength of 450–700nm with sheet resistance of less than 10Ω∕◻. An OLED device employing a multilayer transparent electrode consisting of ITO/APC/ITO emitted light with a higher efficacy than that employing a single layer ITO. On the other hand, the multilayer transparent electrode consisting of AZO/APC/AZO did not emit light even though higher corrosion resistance than ITO/APC/ITO was expected.
Tin removal from extreme ultraviolet collector optics by inductively coupled plasma reactive ion etching
Authors: Shin H. , Srivastava S. N. , Ruzic D. N.
Published: May 2008

Tin (Sn) has the advantage of delivering higher conversion efficiency compared to other fuel materials (e.g., Xe or Li) in an extreme ultraviolet (EUV) source, a necessary component for the leading next generation lithography. However, the use of a condensable fuel in a lithography system leads to some additional challenges for maintaining a satisfactory lifetime of the collector optics. A critical issue leading to decreased mirror lifetime is the buildup of debris on the surface of the primary mirror that comes from the use of Sn in either gas discharge produced plasma (GDPP) or laser produced plasma (LPP). This leads to a decreased reflectivity from the added material thickness and increased surface roughness that contributes to scattering. Inductively coupled plasma reactive ion etching with halide ions is one potential solution to this problem. This article presents results for etch rate and selectivity of Sn over SiO2 and Ru. The Sn etch rate in a chlorine plasma is found to be much higher (of the order of hundreds of nm/min) than the etch rate of other materials. A thermally evaporated Sn on Ru sample was prepared and cleaned using an inductively coupled plasma etching method. Cleaning was confirmed using several material characterization techniques. Furthermore, a collector mock-up shell was then constructed and etching was performed on Sn samples prepared in a Sn EUV source using an optimized etching recipe. The sample surface before and after cleaning was analyzed by atomic force microscopy, x-ray photoelectron spectroscopy, and Auger electron spectroscopy. The results show the dependence of etch rate on the location of Sn samples placed on the collector mock-up shell.
Oxidation of silicon nanowires for top-gated field effect transistors
Authors: Liu Bangzhi , Wang Yanfeng , Ho Tsung-ta , Lew Kok-Keong , Eichfeld Sarah M. , Redwing Joan M. , Mayer Theresa S. , Mohney Suzanne E.
Published: May 2008

The oxidation of unintentionally doped p-type silicon nanowires grown by the vapor-liquid-solid (VLS) method and their integration into top-gated field effect transistors is reported. Dry thermal oxidation of as-grown silicon nanowires with diameters ranging from 20to400nm was carried out at 700 and 900°C with or without the addition of a chlorinated gas source. The oxidation rate was strongly dependent on the as-grown nanowire diameter, with the large-diameter nanowires oxidizing up to five times faster than the smallest nanowires at 900°C. At each diameter, the addition of trichloroethane (TCA) enhanced the rate compared to oxidation in pure O2. Top-gated field effect transistors fabricated from nanowires oxidized at 700°C had significantly less hysteresis in their subthreshold properties when TCA was added, but oxidation at 900°C with or without TCA provided hysteresis-free devices with improved subthreshold slope. Such enhancements in the electrical properties are expected based on advances in planar silicon process technology and emphasizes the importance of incorporating these techniques for VLS-grown nanowire devices.
Thermal conductivity of semi-insulating, p-type, and n-type GaN films on sapphire
Authors: Jagannadham K. , Berkman E. A. , Elmasry N.
Published: May 2008

The thermal conductivity of undoped, n-type, and p-type GaN films deposited on (0001) substrates of sapphire was measured by the 3-ω method in the temperature range between 215 and 300K. The thickness, thermal conductivity, and heat capacity of the individual layers were used to simulate the experimental value of the increment in temperature of the heater using a multilayer model. The thermal conductivity of undoped GaN film was found to be much higher than that of p-type film. Also, the thermal conductivity of n-type GaN film was slightly smaller than that of p-type film. Modeling of the temperature dependence of the thermal conductivity in the films showed that phonon-dopant and three-phonon umklapp scattering are important. Smaller thickness and hence smaller volume fraction of the film with lower dislocation density was also found to be responsible for lower thermal conductivity in n- and p-type GaN films.
Preparation and microstructural characterization of TiC and Ti0.6W0.4∕TiC0.6 composite thin films obtained by activated reactive evaporation
Authors: Montes de Oca J. A. , LePetitcorps Y. , Manaud J.-P. , Vargas García J. R.
Published: May 2008

Titanium carbide-based coatings were deposited on W substrates at a high coating growth rate by activated reactive evaporation at 500 and 600°C in a L560 Leybold system using propene as reactive atmosphere. The crystal structure, lattice parameter, preferred orientation, and grain size of the coatings were determined by x-ray diffraction technique using CuKα. The analysis of the coating morphology was performed by scanning electron microscopy (SEM), and the composition of the films was analyzed by Auger electron spectroscopy and electron-probe microanalysis. Experimental results suggested that temperature was one of the most important parameters in the fabrication of stoichiometric TiC coatings. Thus, TiC coatings were obtained at 600°C, whereas TiC0.6 nonstoichiometric coatings codeposited with a free Ti phase were obtained at 500°C, giving rise to the formation of a composite thin film. After annealing at 1000°C, the stoichiometric films remained stable, but a crack pattern was formed over the entire coating surface. In addition, Ti0.6W0.4∕TiC0.6 composite thin coatings were obtained for the films synthesized at 500°C. The formation of a Ti0.6W0.4 ductile phase in the presence of a TiC0.6 phase was responsible to avoid the coating cracking.
Preparation of α-Al2O3 thin films by electron cyclotron resonance plasma-assisted pulsed laser deposition and heat annealing
Authors: Yu D. , Lu Y. F. , Xu N. , Sun J. , Ying Z. F. , Wu J. D.
Published: May 2008

Optically transparent α-Al2O3 thin films were prepared on Si(100) substrates by electron cyclotron resonance (ECR) plasma-assisted pulsed laser deposition followed by heat annealing. Oxygen plasma produced through ECR microwave discharge was used to assist reactive deposition of amorphous aluminum oxide thin films from metallic aluminum and the deposited films were then annealed in air at temperatures ranging from 500to1100°C. The as-deposited and heat-annealed films were characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, and X-ray diffraction analysis. The as-deposited films exhibit an amorphous structure, undergo a phase transition upon heat annealing, and convert to α form of Al2O3 with rhombohedral crystalline structure after annealing at 1100°C. A SiO2 layer is also found to form between the aluminum oxide film and the Si substrate after the samples were annealed above 700°C. Optical characterization reveals that aluminum oxide films deposited on sapphire substrates under the same deposition conditions are transparent from ultraviolet to near-infrared regions, and the transparency increases over 10% for the α-Al2O3 films crystallized through annealing at 1100°C as compared with that of the as-deposited films.
Recombination probability of oxygen atoms on dynamic stainless steel surfaces in inductively coupled O2 plasmas
Authors: Stafford Luc , Guha Joydeep , Donnelly Vincent M.
Published: May 2008

The authors have investigated the influence of plasma exposure time (t) on the Langmuir-Hinshelwood (i.e., delayed) recombination of O atoms on electropolished stainless steel surfaces using the spinning-wall method. They found a recombination probability (γO) of 0.13±0.01 after about 60min of plasma exposure. γO decreased to 0.09±0.01 for t⩾12h and was independent of the O flux impinging onto the surface. These recombination probabilities are much lower than those obtained in plasma chambers exclusively made of stainless steel, but similar to values recorded in stainless steel reactors with large silica surfaces exposed to the plasma. Near real-time elemental analysis by in situ Auger electron spectroscopy showed that the stainless steel surface became rapidly coated with a Si-oxide-based layer (Fe:[Si+Al]:O≈2:1:9 for t=60min and 1:2:9 for t=12h), due to the slow erosion of the silica discharge tube and anodized Al chamber walls. Thus, the recombination probability of oxygen atoms on stainless steel in plasma reactors with large amounts of exposed silica is largely determined by the amount of sputtered silica coating the chamber walls.
Methods of producing plasma enhanced chemical vapor deposition silicon nitride thin films with high compressive and tensile stress
Authors: Belyansky M. , Chace M. , Gluschenkov O. , Kempisty J. , Klymko N. , Madan A. , Mallikarjunan A. , Molis S. , Ronsheim P. , Wang Y. , Yang D. , Li Y.
Published: May 2008

Various methods of generating high stress in thin plasma enhanced chemical vapor deposition (PECVD) silicon nitride (SiN) films are reported. Besides the mainstream variation of plasma power and other process parameters, novel techniques such as creation of high density layers in multilayer PECVD structures or exposure of SiN films to ultraviolet radiation are shown to increase intrinsic film stress. Thin PECVD SiN films have been analyzed by a variety of analytical techniques including Fourier transform infrared spectroscopy, x-ray reflectivity (XRR), time of flight secondary ion mass spectrometry, and transmission electron microscopy to collect data on bonding, density, chemical composition, and film thickness. The level of bonded hydrogen as well as film density has been found to correlate with film stress. Creation of multilayer structures and high density layers help to build up more stress compared to a standard single layer film deposition. Both the density and number of layers in a film, characterized by XRR, affect the stress. Higher density layers affect diffusion profiles and show impurity oscillations corresponding to a multilayer film structure. Ultraviolet cure allows the film to achieve higher level of tensile stress at relatively low temperatures (400–500°C), comparable to the result of film high temperature annealing.
Role of chamber dimension in fluorocarbon based deposition and etching of SiO2 and its effects on gas and surface-phase chemistry
Authors: Joseph E. A. , Zhou B.-S. , Sant S. P. , Overzet L. J. , Goeckner M. J.
Published: May 2008

It is well understood that chamber geometry is an influential factor governing plasma processing of materials. Simple models suggest that a large fraction of this influence is due to changes in basic plasma properties, namely, density, temperature, and potential. However, while such factors do play an important role, they only partly describe the observed differences in process results. Therefore, to better elucidate the role of chamber geometry in this work, the authors explore the influence of plasma chemistry and its symbiotic effect on plasma processing by decoupling the plasma density, temperature, and potential from the plasma-surface (wall) interactions. Specifically, a plasma system is used with which the authors can vary the chamber dimension so as to vary the plasma-surface interaction directly. By varying chamber wall diameter, 20–66cm, and source-platen distance, 4–6cm, the etch behavior of SiO2 (or the deposition behavior of fluorocarbon polymer) and the resulting gas-phase chemistry change significantly. Results from in situ spectroscopic ellipsometry show significant differences in etch characteristics, with etch rates as high as 350nm∕min and as low as 75nm∕min for the same self-bias voltage. Fluorocarbon deposition rates are also highly dependent on chamber dimension and vary from no net deposition to deposition rates as high as 225nm∕min. Etch yields, however, remain unaffected by the chamber size variations. From Langmuir probe measurements, it is clear that chamber geometry results in significant shifts in plasma properties such as electron and ion densities. Indeed, such measurements show that on-wafer processes are limited at least in part by ion flux for high energy reactive ion etch. However, in situ multipass Fourier transform infrared spectroscopy reveals that the line-averaged COF2, SiF4, CF2, and CF3 gas-phase densities are also dependent on chamber dimension at high self-bias voltage and also correlate well to the CFx overlayer stoichiometry under deposition conditions.
Compositional analysis of lead telluride films deposited via pulsed electron-beam ablation
Authors: Steigerwald A. , Aga R. , Collins W. E. , Mu R. , Hmelo A. B.
Published: May 2008

Pulsed electron deposition (PED) is a novel thin film growth technique with unique advantages for industrial-scale manufacturing. Previously, no investigations into local deviations in stoichiometry have been carried out. The authors report the first analysis of large-scale compositional variations in thin films deposited via PED. Ablated lead telluride (PbTe) was deposited at various target-substrate distances on 5cm2 substrates. Rutherford backscattering was employed to systematically analyze compositional variation at different positions within the deposition. Stoichiometry is reported as a function of both distance and angular displacement. Deposition rates for the center of the ablated plume are reported. The authors show PED to be capable of uniform deposition over areas of moderate (0.5–1cm2) size, with an enrichment of heavier elements in the center of the film. The results are explained within the context of expanding plasma behavior.
INVARIANT DIFFERENTIAL OPERATORS FOR NON-COMPACT LIE GROUPS: PARABOLIC SUBALGEBRAS
Authors: DOBREV V. K.
Published: May 2008

In the present paper, we start the systematic explicit construction of invariant differential operators by giving explicit description of one of the main ingredients — the cuspidal parabolic subalgebras. We explicate also the maximal parabolic subalgebras, since these are also important even when they are not cuspidal. Our approach is easily generalized to the supersymmetric and quantum group settings and is necessary for applications to string theory and integrable models.
AN EXACT COSMOLOGICAL SOLUTION WITH ENERGY EXCHANGE BETWEEN VACUUM AND MATTER, AND VACUUM AND RADIATION
Authors: MA GUANG-WEN , MA JING-YUAN
Published: May 2008

We extend the cosmological version with energy exchange proposed by Barrow and Clifton from the case of two fluids to the case of three fluids, and find an exact cosmological solution for spatially flat Robertson–Walker metric. In this solution the integrating constants and the parameters introduced by the model are determined from cosmic observations.
A MODEL OF QUANTUM OSCILLATOR WITH DISCRETE SPACE
Authors: KACHURYK I. I. , KLIMYK A. U.
Published: May 2008

We construct a new model of the quantum oscillator, which is related to the discrete q-Hermite polynomials of the second type. The position and momentum operators in the model are appropriate operators of the Fock representation of a deformation of the Heisenberg algebra. These operators have a discrete non-degenerate spectra. These spectra are spread over the whole real line. Coordinate and momentum realizations of the model are constructed. Coherent states are explicitly given.
PLETHORA OF q-OSCILLATORS POSSESSING PAIRWISE ENERGY LEVEL DEGENERACY
Authors: GAVRILIK A. M. , REBESH A. P.
Published: May 2008

Using the q, p-deformed oscillators as basic generating system, we obtain diverse classes (which form distinct sectors of functional continua) of novel versions of q-deformed oscillators, all of which share the property of "accidental" degeneracy within a fixed pair of energy levels Em = Em+1, m ≥ 1, occurring at the real deformation parameter fixed by an appropriate value q(m) that depends on m and on particular model. Likewise, the degeneracy E0 = Ek (where k ≥ 2) takes place, for properly fixed q = q(k), in most of those models. The formerly studied model of q-oscillator known as the Tamm–Dancoff cutoff deformed oscillator is contained in the continua as isolated special case.
ON THE EQUATIONS GOVERNING THE FLOW OF MECHANICALLY INCOMPRESSIBLE, BUT THERMALLY EXPANSIBLE, VISCOUS FLUIDS
Authors: FARINA ANGIOLO , FASANO ANTONIO , MIKELIĆ ANDRO
Published: May 2008

In this paper, the stationary flow of a heat conducting viscous fluid, which is mechanically incompressible but thermally expansible is studied. The flow takes place in a bounded domain and the discharge is prescribed. The thermodynamical modeling of this situation is discussed first. Then the stationary model with zero Eckert number and prove existence of a solution is studied. Using these results, the Oberbeck–Boussinesq system obtained in the zero expansivity limit is proved. Next, uniqueness for small data and the regularity of the weak solutions is proved. For the unique regular solution the higher order corrections for Boussinesq' approximation and we constructed the error estimate with respect to the thermal expansivity coefficient is proved. The next order correction in this limit is an Oseen type momentum equation coupled with a linear advection/diffusion equation for the temperature. Such higher order correction seems to be new in the literature.
ALGEBRAIC TIME DECAY FOR THE BIPOLAR QUANTUM HYDRODYNAMIC MODEL
Authors: LI HAI-LIANG , ZHANG GUOJING , ZHANG KAIJUN
Published: May 2008

The initial value problem is considered in the present paper for the bipolar quantum hydrodynamic (QHD) model for semiconductors in ℝ3. The unique strong solution exists globally in time and tends to the asymptotical state with an algebraic decay rate as time goes to infinity is proved. And, the global solution of linearized bipolar QHD system decays in time at an algebraic decay rate from both above and below is shown. This means that in general we cannot get an exponential time-decay rate for bipolar QHD system, which is different from the case of unipolar QHD model (where global solutions tend to the equilibrium state at an exponential time-decay rate) and is mainly caused by the nonlinear coupling and cancelation between two carriers. Moreover, it is also shown that the nonlinear dispersion does not affect the long time asymptotic behavior, which by product gives rise to the algebraic time-decay rate of the solution of the bipolar hydrodynamical model in the semiclassical limit.
TRAVELLING CALCIUM WAVES IN SYSTEMS WITH NON-DIFFUSING BUFFERS
Authors: KAZMIERCZAK BOGDAN , VOLPERT VITALY
Published: May 2008

The existence and structural stability of travelling waves of systems of the free cytosolic calcium concentration in the presence of immobile buffers are studied. The proof is carried out by passing to zero with the diffusion coefficients of buffers. Thus, its method is different from Ref. 13 where the existence is proved straightforwardly.