bluuebunny/crossref_metadata_2025 huggingface dataset:
Developing entrepreneurial graduates: an action‐learning approach
Authors: Jones‐Evans Dylan , Williams William , Deacon Jonathan
Published: July 2002

Earlier this year, the University of Glamorgan Business School launched a conceptually new postgraduate programme, the Diploma in Entrepreneurial practice (DEP). This is a nine‐month long, full‐time course with selected business graduates undertaking a programme of study based around simulated and real projects to enhance their entrepreneurial skills, knowledge and attitudes. Aims to evaluate the inclusion of “taught” learning within what is fundamentally an action‐learning programme, and to discuss the issues around effective marketing of the DEP to industry and educationalists in Wales. Fundamental to the philosophy underpinning the DEP programme is that elements of entrepreneurship can be learned, and this paper explores the modes of learning entrepreneurship applied in the DEP programme and makes some initial assessment as to the different modes’ applicability on a course of this kind.
The learning aims of higher education: a personal reflection
Authors: Bourner Tom
Published: July 2002

Considers the role of higher education with reference to the development of students as people rather than simply receptacles for knowledge. Charts the author’s development as an educationist and suggests a current total of six learning aims which he sees to be of central importance in higher education, including such factors as disseminating up‐to‐date knowledge and facilitating personal development of students.
Supervisor and manager styles in handling discipline and grievance
Authors: Rollinson Derek , Hook Caroline , Foot Margaret , Handley Janet
Published: July 2002

Examines the relative influence of a number of factors that can affect the approach (handling style) of a supervisor or manager when dealing with a disciplinary or grievance incident. Uses the same data set as the earlier paper in the same series. Finds that, for discipline, the most influential factors are the inconvenience for the manager of particular employee transgression and the length of employee service, with additional but comparatively minor effects for employee gender and the manager’s prior training and experience in handling issues. Identifies the most influential factors with grievance as the extent to which an issue challenges the authority of the manager, the length of employee service, the employee’s gender and, to a lesser extent, the gender of the manager handling the issue. Outlines the implications of these results for future research and for the training of supervisors and managers.
Downsizing: is it always lean and mean?
Authors: Kinnie Nicholas , Hutchinson Sue , Purcell John
Published: July 2002

Discusses how downsizing has been associated with the move towards lean working in organisations and with having negative consequences for employees. Considers the extent to which downsizing is lean and mean drawing on an extensive review of the available literature. Concludes that downsizing is rarely lean since it usually takes the form of quantitative changes in employment rather than qualitative changes in the process of managing. Evidence also suggests that downsizing usually has an adverse effect on both employees who leave and those who remain with the organisation. Yet this meanness is not inevitable since it depends partly on the extent to which human resources issues are considered.
New generation servomotors
Authors: Kusuda Yoshihiro
Published: July 2002

During the past couple of years advances in technology have dramatically improved servomotor torque performance, and reduced their size and weight to one third compared to previous servomotors. This article describes the background, explores new opportunities in machine design and highlights new applications using advanced motion control to make the most of this technology.
Business ethics and social responsibility in transition economies
Authors: Fülöp Gyula , Hisrich Robert D. , Szegedi Krisztina
Published: July 2002

The newly developed market‐oriented system in Hungary requires new values, different abilities, and more sensitivity to a wide variety of issues on the part of corporate leadership. The nature of these values and abilities will more than likely vary depending on the industry. The purpose of this study was to examine the view of business ethics and social responsibility among Hungarian managers in both the business and non‐business sectors. The results indicate differences between the examined groups and diverse opinions among participants within each group.
Organizational change and job redesign in integrated manufacturing: a macro‐organizational to micro‐ organizational perspective
Authors: Appelbaum Steven H. , Grigore Marius L.
Published: July 2002

Based on the latest research on the topic of integrated manufacturing (IM), attempts to integrate macro‐organizational and micro‐organizational factors which have been found to relate to the new manufacturing paradigm. Commences with a definition of IM and its three prominent components: advanced manufacturing technologies (AMT) just‐in‐time inventory and total quality management. Follows with an evaluation of the moderating role of the organizational context in the relationship between IM and job design characteristics. Critically examines organizational performance, size, dependency as well as structure and culture and their effects on such implementation outcomes as: productivity, job satisfaction and job‐related strain. Investigates the impact of IM on human resource practices: staffing, training, performance appraisal and rewards. Concludes with a suggested implementation sequence which identifies critical elements and develops strategies and priorities for a successful transition to IM.
School climate in elementary and secondary schools: views of Cypriot principals and teachers
Authors: Pashiardis Georgia
Published: July 2002

Aims to examine and present the beliefs of elementary and secondary school principals and teachers concerning their school’s climate. Investigates four parameters related to school climate, namely: communication, collaboration, organizational structure, and students. Both elementary and secondary principals and teachers indicated that the climate in their particular schools is satisfactory with an overall mean of 2.33 on a three‐point Likert‐type scale. The lowest mean was given to the parameter organizational structure (2.26), the second to the parameter students (2.29) and the third to the parameter collaboration (2.31). Therefore, one could conclude that the above areas are in most need of improvement. Based on gender, one general comment would be that men seemed to feel worse about their particular school’s climate than women. Further, more experienced teachers had slightly different views when compared with less experienced teachers in two parameters of the questionnaire (organizational structure and students).
Estimating thermal resistance of the bedding assembly from thickness of materials
Authors: Wilson C.A. , Niven B.E. , Laing R.M.
Published: July 2002

The purposes of this work were to determine: whether thickness of single layers can be used to accurately predict thickness and thermal resistance of multiple layer assemblies; and to identify variables affecting the total thickness (i.e. textile plus air layers) of bedding during simulated use. Thickness was determined when: materials were flat; and arranged over an infant manikin simulating use. Thermal resistance was measured using a guarded‐hotplate similar to that specified in ISO 11092:1993(E). During simulated use, the site of measurement, body position, tucking, and product type significantly affected thickness of bedding. Equations for predicting thickness and thermal resistance (dry) of multiple‐layer materials are described. While it was possible to predict thickness and thermal resistance of flat bedding from estimated values, extrapolation to bedding during simulated use was considered inappropriate, with significant differences of over 1,000 per cent.
Issues in developing a school leadership preparation programme in a post‐communist republic of the former Soviet Union
Authors: Reilly David H. , Brown John
Published: July 2002

Examines the complex issues involved in developing a school leadership programme in the Republic of Georgia. Intends to serve as an inventory for other newly independent states seeking to transform their educational systems. By discussing eight conditions that result in differences in the practice of education among countries, frames a perspective for additional research. Chronicles the historical context of Georgian life and culture and includes a discussion of education reform efforts, philosophy and the current education system. Interwoven in the historical developments and traditions and their interaction with current economic, social and political realities, presents ten major issues that must be resolved prior to the development of an effective school leadership programme.
Strategies of educational decentralization: key questions and core issues
Authors: Hanson E. Mark
Published: July 2002

Educational decentralization is a popular reform theme of governments around the world, but with motives, strategies and outcomes as different as the countries themselves. For researchers and policy makers alike, there is a growing need to synthesize the positive and negative aspects of these national strategies and experiences. The objective of this paper is to identify and explain the key issues and forces that play major roles in shaping organization and management strategies of educational decentralization. Examples from five Hispanic nations that have initiated decentralization reforms will be utilized to illustrate the major points: Colombia, Venezuela, Argentina, Nicaragua and Spain. The paper is organized around a series of questions that tap core decentralization issues, such as national and regional goals, planning, political stress, resource distribution, infrastructure development, and job stability. The paper concludes with a conceptual model of the decentralization process and a series of “lessons learned” from the five nations.
A business approach to effective information technology risk analysis and management
Authors: Halliday Sharon , Badenhorst Karin , von Solms Rossouw
Published: July 2002

Suggests that a number of difficulties are experienced by organizations using conventional risk analysis and management. “Conventional” refers to those methodologies which are based on the traditional asset/threat/vulnerability model. Identifies a need for an approach that is more suitable for smaller organizations, as well as organizations requiring a quicker, more simplified and less resource‐intensive approach. In light of this requirement, proposes an alternative approach to effective information technology (IT) risk analysis and management. This approach has a business‐oriented focus from an IT perspective.
Evaluating domestic and international Web‐site strategies
Authors: Simeon Roblyn
Published: July 2002

This paper presents the AIPD approach to the evaluation of commercial Web sites within or across borders. The author explains how benchmarking techniques can be used to compare attracting, informing, positioning, and delivering (AIPD) strategies of Web sites in order to clarify strategic opportunities or advantages. The AIPD model is then used to compare the Internet strategies of some Japanese and American banks. Results show that Japanese banks have created more dynamic and content rich Internet environments than their American counterparts. Cultural and institutional differences are given for the contrasting approaches to Web design, information and service delivery.
Virtual team interaction: assessment, consequences, and management
Authors: Potter Richard E. , Cooke Robert A. , Balthazard Pierre A.
Published: July 2002

Virtual teams are typically made up of geographically dispersed experts, supported by computer‐based communication technologies. Though increasingly popular this is still a relatively unstudied organizational form. Virtual team membership is typically based solely on needed expertise; the teams rarely have any history of interaction and their performance potential is unknown. Research shows that teams exhibit constructive, passive, and aggressive interaction styles, which have significant effects on the decisions the teams produce as well as the teams’ satisfaction with those decisions. We present managerial tools for the assessment of conventional and virtual team interaction styles. We detail how the tools are used, and we also discuss how the styles manifest in each medium, and their effects. We give suggestions to team managers on how to use the insights the tools provide to manage their virtual teams for optimal performance.
Empowerment and team development
Authors: Hut Jacqueline , Molleman Eric
Published: July 2002

Based on the four principles of self‐organization formulated by Morgan (1986), a four‐stage implementation model for empowering teams was developed. From the first to the last stage, the attention shifts from routine tasks to non‐routine tasks, from the individual to the group, and from inwards oriented to outwards directed activities. This model was used to develop five teams in an industrial glass producing firm. After two years, team progress was measured by means of a questionnaire and the results were discussed with each team. These data were used to evaluate the viability and applicability of the empowerment plan and to find relevant factors which facilitate or hinder the empowerment process. The results indicate that the step‐by‐step plan facilitates the development of empowered teams but that it should not be seen necessarily as the best or the only way of empowering working groups. Moreover, the attitude and style of management, the team cohesion and the nature of the work involved seem to interfere with team empowerment.
Random circular permutation leading to chain disruption within and near α helices in the catalytic chains of aspartate transcarbamoylase: Effects on assembly, stability, and function
Authors: Beernink Peter T. , Yang Ying R. , Graf Roney , King David S. , Shah Shaival S. , Schachman Howard K.
Published: July 2002

A collection of circularly permuted catalytic chains of aspartate transcarbamoylase (ATCase) has been generated by random circular permutation of the pyrB gene. From the library of ATCases containing permuted polypeptide chains, we have chosen for further investigation nine ATCase variants whose catalytic chains have termini located within or close to an α helix. All of the variants fold and assemble into dodecameric holoenzymes with similar sedimentation coefficients and slightly reduced thermal stabilities. Those variants disrupted within three different helical regions in the wild‐type structure show no detectable enzyme activity and no apparent binding of the bisubstrate analog N‐phosphonacetyl‐l‐aspartate. In contrast, two variants whose termini are just within or adjacent to other α helices are catalytically active and allosteric. As expected, helical disruptions are more destabilizing than loop disruptions. Nonetheless, some catalytic chains lacking continuity within helical regions can assemble into stable holoenzymes comprising six catalytic and six regulatory chains. For seven of the variants, continuity within the helices in the catalytic chains is important for enzyme activity but not necessary for proper folding, assembly, and stability of the holoenzyme.
Modulatory role of focal adhesion kinase in regulating human pulmonary arterial endothelial barrier function
Authors: Mehta Dolly , Tiruppathi Chinnaswamy , Sandoval Raudal , Minshall Richard D. , Holinstat Michael , Malik Asrar B.
Published: July 2002

The adhesive force generated by the interaction of integrin receptors with extracellular matrix (ECM) at the focal adhesion complex may regulate endothelial cell shape, and thereby the endothelial barrier function. We studied the role of focal adhesion kinase (FAK) activated by integrin signalling in regulating cell shape using cultured human pulmonary artery endothelial cells. We used FAK antisense oligonucleotide (targeted to the 3′‐untranslated region of FAK mRNA (5′‐CTCTGGTTGATGGGATTG‐3′) to determine the role of FAK in the mechanism of thrombin‐induced increase in endothelial permeability. Reduction in FAK expression by the antisense augmented the thrombin‐induced decrease in transendothelial electrical resistance (decrease in mock transfected cells of −43 ± 1 % and in sense‐transfected cells of −40 ± 4 %, compared to the decrease in antisense‐transfected cells of −60 ± 3 %). Reduction in FAK expression also prolonged the drop in electrical resistance and prevented the recovery seen in control endothelial cells. Thus, the thrombin‐induced increase in permeability is both greater and attenuated in the absence of FAK expression. Inhibition of actin polymerization with latrunculin‐A prevented the translocation of FAK to focal adhesion sites and tyrosine phosphorylation of FAK and paxillin, and concomitantly reduced the thrombin‐induced decrease in electrical resistance by ∼50 %. Thus, the modulatory role of FAK on endothelial barrier function is dependent on actin polymerization. FAK translocation to focal adhesion complex in endothelial cells guided by actin cables and the consequent activation of FAK‐associated proteins serve to reverse the decrease in endothelial barrier function caused by inflammatory mediators such as thrombin.
Principles of Solar Engineering
Authors: Vliet, Gary C.
Published: July 2002

[S0199-6231(00)01102-3]
Evaluation of Critical Interfacial Friction in Cross Wedge Rolling
Authors: Lovell Michael R.
Published: July 2002

For the purpose of characterizing excess initial slip, the critical value of interfacial friction in the cross wedge rolling (CWR) process is investigated. After describing CWR and its failure mechanisms, an analytical method is presented for determining the critical friction condition in a cross wedge rolling process. Using specialized pin-on-disk experiments, a technique is then introduced for determining the actual friction coefficient in a CWR operation. By comparing the critical and experimental friction coefficient values, a procedure for predicting the likelihood of excess interfacial slip failure in cross wedge rolling is established. The validity of such a procedure is subsequently ascertained for a specific set of operating conditions using the finite element method and CWR prototype experiments.
The Contradicting Assumptions of Zero Transverse Normal Stress and Strain in the Thin Plate Theory: A Justification
Authors: Bhaskar and K. , Varadan T. K.
Published: July 2002

The need and validity of the contradicting assumptions of zero transverse normal stress and the corresponding strain in the classical plate theory are critically examined here. This is done by studying the relative magnitudes of these quantities with respect to other stresses and strains for a test problem amenable to an exact elasticity solution.
Modeling of Micro-Pit Evolution in Rolling or Strip-Drawing
Authors: Sutcliffe M. P. F. , Le H. R. , Ahmed R.
Published: July 2002

The micro-plasto-hydrodynamic lubrication (MPHL) model of pit evolution is extended to account for the variation of sliding speed and strain rate in rolling and drawing processes. Results show that all of the following factors are important: pit angle, lubricant viscosity and pressure viscosity coefficient, material yield stress and sliding speed. Theoretical predictions for the change in pit area during the deformation process are well correlated by a non-dimensional group of these parameters. The model agrees reasonably with the measured change in pit volume and area from drawing experiments on cold rolled stainless steel strip containing both artificial and stochastic roughness.
Modeling Studies to Predict Stresses in Composite Floor Tubes of Black Liquor Recovery Boilers
Authors: Sarma Gorti B. , Keiser James R. , Wang Xun-Li , Swindeman Robert W.
Published: July 2002

The results of finite element modeling studies to analyze the composite floor tubes of recovery boilers used by the pulp and paper industry are presented. Thermal and mechanical analyses have been carried out to examine the changes in the stresses during a normal operating cycle. Three different materials for the clad layer have been studied—304L stainless steel and alloys 625 and 825. The results show that the coefficient of thermal expansion and the strength of the clad layer play a significant role in the stress variation due to the heating and cooling associated with an operating cycle, with implications for the development of cracks in the tubes due to stress corrosion cracking. The analyses also show that axial stress in the carbon steel layer is compressive at the fireside tube crown and tensile in the membrane, which provides a possible explanation for the commonly observed differences in crack propagation in tubes and membranes.
Natural Gas Decarbonization to Reduce CO2 Emission From Combined Cycles—Part II: Steam-Methane Reforming
Authors: Lozza G. , Chiesa P.
Published: July 2002

This paper discusses novel schemes of combined cycle, where natural gas is chemically treated to remove carbon, rather than being directly used as fuel. Carbon conversion to CO2 is achieved before gas turbine combustion. The first part of the paper discussed plant configurations based on natural gas partial oxidation to produce carbon monoxide, converted to carbon dioxide by shift reaction and therefore separated from the fuel gas. The second part will address methane reforming as a starting reaction to achieve the same goal. Plant configuration and performance differs from the previous case because reforming is endothermic and requires high temperature heat and low operating pressure to obtain an elevated carbon conversion. The performance estimation shows that the reformer configuration has a lower efficiency and power output than the systems addressed in Part I. To improve the results, a reheat gas turbine can be used, with different characteristics from commercial machines. The thermodynamic efficiency of the systems of the two papers is compared by an exergetic analysis. The economic performance of natural gas fired power plants including CO2 sequestration is therefore addressed, finding a superiority of the partial oxidation system with chemical absorption. The additional cost of the kWh, due to the ability of CO2 capturing, can be estimated at about 13–14 mill$/kWh.
Characterization of the Effect of Corrugation Angles on Hydrodynamic and Heat Transfer Performance of Four-Start Spiral Tubes
Authors: Chen X. D. , Xu X. Y. , Nguang S. K. , Bergles Arthur E.
Published: July 2002

A series of four-start spirally corrugated tubes has been subjected to heat transfer and hydrodynamic testing in a double-pipe heat exchanger. The study has been focused on the non-symmetric nature of the corrugation angles along the longitudinal direction. Both friction factors and heat transfer coefficients inside the tubes have been correlated against various process parameters. It can be shown that by altering the internal non-symmetric wavy shapes of the tubes, one is able to manipulate heat transfer and friction characteristics. The experimental results have been compared with some popular correlation models developed previously for both friction and heat transfer for corrugated tubes. Considerable differences between the experimental results and the predictions made using the existing correlations have been found and the probable causes have been discussed. Performance evaluation criteria are presented using the standard constant power criterion. A neural network modeling approach has been taken so that, based on the limited data, one can generate the contour showing the effect of corrugation angle on heat transfer coefficient for geometry optimization purposes.
Modeling of Heat Transfer and Kinetics of Physical Vapor Transport Growth of Silicon Carbide Crystals
Authors: Chen Q.-S. , Zhang H. , Prasad V. , Balkas C. M. , Yushin N. K.
Published: July 2002

Wide-bandgap silicon carbide (SiC) substrates are needed for fabrication of electronic and optoelectronic devices and circuits that can function under high-temperature, high-power, high-frequency conditions. The bulk growth of SiC single crystal by physical vapor transport (PVT), modified Lely method involves sublimation of a SiC powder charge, mass transfer through an inert gas environment, and condensation on a seed. Temperature distribution in the growth system and growth rate profile on the crystal surface are critical to the quality and size of the grown SiC single crystal. Modeling of SiC growth is considered important for the design of efficient systems and reduction of defect density and micropipes in as-grown crystals. A comprehensive process model for SiC bulk growth has been developed that incorporates the calculations of radio frequency (RF) heating, heat and mass transfer and growth kinetics. The effects of current in the induction coil as well as that of coil position on thermal field and growth rate have been studied in detail. The growth rate has an Arrhenius-type dependence on deposition surface temperature and a linear dependence on the temperature gradient in the growth chamber.
A Biomechanical Model of the Foot: The Role of Muscles, Tendons, and Ligaments
Authors: Salathe Eric P. , Arangio G. A.
Published: July 2002

A biomechanical model of the foot is developed and analyzed to determine the distribution of support under the metatarsal heads, the tension in the plantar aponeurosis, and the bending moment at each of the joints of the foot. This model is an extension of our earlier work to include the role of muscles, tendons, and ligaments. Two cases are presented: in the first the center of gravity of the body is over the mid foot, and in the second, the center of gravity is anterior, over the metatarsals, and no support is provided by the heel. The model shows the extent to which the muscles reduce the force in the supporting ligaments at each of the joints and decrease the tension in the plantar aponeurosis, and that this effect is more pronounced when the center of gravity of the body is moved forward.
Scaffolds for Engineering Smooth Muscle Under Cyclic Mechanical Strain Conditions
Authors: Kim Byung-Soo , Mooney David J.
Published: July 2002

Cyclic mechanical strain has been demonstrated to enhance the development and function of engineered smooth muscle (SM) tissues, but appropriate scaffolds for engineering tissues under conditions of cyclic strain are currently lacking. These scaffolds must display elastic behavior, and be capable of inducing an appropriate smooth muscle cell (SMC) phenotype in response to mechanical signals. In this study, we have characterized several scaffold types commonly utilized in tissue engineering applications in order to select scaffolds that exhibit elastic properties under appropriate cyclic strain conditions. The ability of the scaffolds to promote an appropriate SMC phenotype in engineered SM tissues under cyclic strain conditions was subsequently analyzed. Poly(L-lactic acid)-bonded polyglycolide fiber-based scaffolds and type I collagen sponges exhibited partially elastic mechanical properties under cyclic strain conditions, although the synthetic polymer scaffolds demonstrated significant permanent deformation after extended times of cyclic strain application. SM tissues engineered with type I collagen sponges subjected to cyclic strain were found to contain more elastin than control tissues, and the SMCs in these tissues exhibited a contractile phenotype. In contrast, SMCs in control tissues exhibited a structure more consistent with the nondifferentiated, synthetic phenotype. These studies indicate the appropriate choice of a scaffold for engineering tissues in a mechanically dynamic environment is dependent on the time frame of the mechanical stimulation, and elastic scaffolds allow for mechanically directed control of cell phenotype in engineered tissues. [S0148-0731(00)00103-5]
A Study of Burr Formation Processes Using the Finite Element Method: Part II—The Influences of Exit Angle, Rake Angle, and Backup Material on Burr Formation Processes
Authors: Park I. W. , Dornfeld D. A.
Published: July 2002

Finite element models in orthogonal cutting are presented in order to examine the influences of exit angles of the workpiece, tool rake angles, and backup materials on burr formation processes in 304 L stainless steel in particular. Based on the metal-cutting simulation procedure proposed by the authors, a series of stress and strain contours and final burr/breakout configurations are obtained. The burr formation mechanisms with respect to five different exit angles are found, and duration of the burr formation process increases with an increase of exit angle, resulting in different burr/breakout configurations. Based on the development of negative shear stress in front of the tool tip, the tool tip damage, what is called “chipping,” is investigated. Also, with fixed cutting conditions and workpiece exit geometry, the influence of the rake angle is found to be closely related to the rate of plastic work in steady-state cutting because the larger the rate of plastic work in steady-state cutting, the earlier the burr initiation commences. Furthermore, in order to effectively minimize the burr size, three cases of backup material influences on burr formation processes are examined. It is found that the burr size can be effectively minimized when the backup material supports the workpiece only up to the predefined machined surface. [S0094-4289(00)01402-X]
Oscillating Stress on Viscoelastic Behavior of Thermoplastic Polymers
Authors: Scavuzzo Rudolph J.
Published: July 2002

Polymers are used in many applications where they are subjected to cyclic stresses. PVC and HDPE piping are often used in systems that include rotating machinery that cause mechanical vibration. Recent testing of thermoplastics indicates that there may be a large effect on the viscoelastic strains of thermoplastics from oscillating stresses. Cyclic loading on the permanent set of cross-linked elastomers has been studied. Perhaps, as expected, the effect of the oscillating behavior is measurable. Two types of tests have been conducted. First, tensile tests on HDPE standard specimens were conducted where oscillating stresses were superimposed onto an initial static or mean stress. These measurements showed a rapid decrease in the oscillating stresses when compared to measurements when steady nonoscillating stresses are applied to the same type of specimen. In the second test series, pressurized HDPE piping was subject to oscillating bending stresses. Ratcheting of the hoop strains in the pipe occurs. Results show that these strains follow the constitutive relationships of linear viscoelasticity and experimental results imply that viscoelastic changes are accelerated by stress oscillations. These preliminary results seem to indicate that the effects of oscillating stresses on the viscoelastic behavior of thermoplastics may be significant. A systematic study is required to further understand this behavior. [S0094-9930(00)02403-3]
Parametric Sensitivity Analysis of Coupled Acoustic-Structural Systems
Authors: Scarpa F.
Published: July 2002

In this paper a method for the parametric sensitivity of acoustic-structural coupled systems is presented. The symmetrical Eulerian formulation is applied in order to calculate the coupled frequencies and modes. From a state space formulation of the problem a sensitivity algorithm is developed to obtain the derivatives of the coupled frequencies and modes of the system versus a design parameter vector. The algorithm is based on the properties of the complex conjugate eigenvalues obtained from the solution of the state space equation. Numerical examples from an acoustic rectangular cavity backed by a simply supported plate are presented. The comparison reveals a good agreement between numerical and analytical results. [S0739-3717(00)00802-3]
Analysis of a Poly(oxymethylene) Polymer by XPS
Authors: Lannon John M. , Meng Qingru
Published: July 2002

We report x-ray photoemission spectra for a poly(oxymethylene) (POM) polymer (also known as acetal). XPS spectra were acquired with a SSI model SSX-100 instrument using monochromated Al Kα x-rays. We present the survey spectrum (binding energy 0–1000 eV) and a narrow spectrum of the C 1s and O 1s photoelectron peaks.
At-wavelength extreme ultraviolet lithography mask inspection using a Mirau interferometric microscope
Authors: Haga Tsuneyuki , Takenaka Hisataka , Fukuda Makoto
Published: July 2002

We have developed a novel at-wavelength inspection system for extreme ultraviolet lithography (EUVL) masks that employs an EUV interferometric microscope. The main advantage of this system is the ability to observe a mask directly and detect defects as they are, thus allowing phase defects to be detected even in a finished mask with the absorber. Moreover, this system provides the high spatial resolution of an EUV microscope, the high phase resolution of interferometric measurements, and a high throughput. We investigated the defect detection capability using several types of EUVL masks with programmed defects, and found that programmed phase defects with steps as low as 5 nm can be detected. These results demonstrate the capabilities of a Mirau interferometric microscope for at-wavelength EUVL mask inspection. Considering the diffraction-limited resolution of Schwarzschild optics (∼50 nm), this system should be applicable to the subhundred nanometer technology node.
Analysis of Langmuir probe data: Analytical parametrization, and the importance of the end effect
Authors: Narasimhan G. , Steinbrüchel Ch.
Published: July 2002

The ion current to a cylindrical or spherical Langmuir probe can be represented as Ii=I0a(−X)b, where I0 is the ion flux to the edge of the probe sheath, X is the dimensionless probe potential, and a and b are parameters depending on the ratio of the probe radius rp to the Debye length λD and the probe geometry. We present analytical expressions for a and b which are valid over a wide range of rp/λD. We also discuss under which conditions the end of a cylindrical probe contributes appreciably to the probe current. Neglecting the end effect may lead to a significant overestimate of the ion density.
Thin film growth of reactive sputter deposited tungsten–carbon thin films
Authors: Rack Philip D. , Peterson Jeffrey J. , Li Jie , Geiculescu A. C. , Rack H. J.
Published: July 2002

Tungsten–carbon thin films have been reactively sputter deposited in various Ar–CH4 gas mixtures and the growth kinetics of the reactive deposition process have been elucidated. The films are amorphous as-deposited with partial crystallization of W2C and WC occurring following a 1100 °C–1 min rapid thermal anneal. Carbon incorporation within the W–C films is attributed to the flux of CH3 radicals impinging on the growth surface. Although they have a significantly lower concentration (∼0.1%) than the CH4 molecules contained within the plasma, their sticking coefficient is significantly larger than that of CH4. In addition, the change in the incorporation rate of carbon in the W–C films at higher CH4 (and subsequently CH3) concentrations has been shown to be due to the changes in the growth surface; as the CH3 flux increases, the growth surface becomes carbon terminated and decreases the incorporation of carbon because of the low CH3–C sticking coefficient.
Visible emission from amorphous AlN thin-film phosphors with Cu, Mn, or Cr
Authors: Martin A. L. , Spalding C. M. , Dimitrova V. I. , Van Patten P. G. , Caldwell M. L. , Kordesch M. E. , Richardson H. H.
Published: July 2002

Luminescence studies of amorphous AlN incorporated with pure Cu, Mn, or Cr and codeposited with (Cu, Tb, Mn) were performed at 300 K. Thin films of Cu, Mn, and Cr amorphous AlN, ∼200 nm thick, were grown on p-Si(111) substrates using rf magnetron sputtering in a nitrogen atmosphere. Cathodoluminescence showed that pure Cu incorporated amorphous AlN films have strong emission in the blue (∼420 nm) and Mn and Cr incorporated films luminescence in the red (∼690 nm). Cr3+ emission is likely more intense than Mn4+ because chromium does not suffer from incomplete charge compensation in the III–V semiconductor. Luminescence studies of layered structures where pure Cu incorporated films are grown on top of pure Cr incorporated films reveal emission from both Cr and Cu ions. The migration of Cr ions during the 1000 °C luminescence activation step is confirmed with secondary ion mass spectrometry depth profiling. Co-deposited films of Cu, Tb, and Mn show Cu emission around 530 nm instead of 420 nm due to coactivation by Mn.
Physical and electrical properties of noncrystalline Al2O3 prepared by remote plasma enhanced chemical vapor deposition
Authors: Johnson Robert S. , Lucovsky Gerald , Baumvol Isreal
Published: July 2002

Noncrystalline Al2O3 dielectric films have been synthesized by remote plasma enhanced chemical vapor deposition (RPECVD) and deposited on (i) H-terminated Si(100) and (ii) on SiO2 prepared by remote plasma assisted oxidation and RPECVD on Si(100) substrates using organometallic source gases injected downstream from a He/O2 plasma. Chemical composition and morphology of the Al2O3 films and their interfaces have been studied by Auger electron spectroscopy (AES), Fourier transform infrared spectroscopy, nuclear resonance profiling (NRP), and x-ray diffraction (XRD). Previous studies in which Al2O3 was deposited by thermal CVD, rapid thermal CVD, (RTCVD), direct PECVD, and physical vapor deposition generally resulted in relatively thick SiO2 or Al-silicate interfacial layers which impact adversely on the highest attainable capacitance. In line AES and NRP indicate the as-deposited RPECVD films are fully oxidized on deposition, and their interfaces can be chemically abrupt with Si oxide or Al silicate interfacial layers that are no more than 0.6 to 0.8 nm thick. However, these relatively abrupt interfaces do not ensure good device performance. Electrical measurements indicate negative fixed charge on the order of 1012 charges/cm2. The fixed charge resides at the Al2O3 interface, and can be moved away from the silicon substrate by deposition of a thin, ∼1–2 nm, intermediate layer of RPECVD SiO2.
Cyclic plasma deposition of SiO2 films at low temperature (80 °C) with intermediate plasma treatment
Authors: Yi Chung , Rhee Shi Woo
Published: July 2002

Cyclic plasma enhanced chemical vapor deposition (CPECVD) with intermediate O2 plasma treatment was studied to obtain high quality gate oxide at near room temperature (80 °C) using tetraethylorthosilicate (TEOS) and oxygen. SiO2 films were characterized by Fourier transform infrared spectroscopy, x-ray photoelectron spectroscopy, and secondary ion mass spectroscopy. Periodic O2 plasma intermediate treatment during oxide deposition was effective in removing the impurities in the oxide film and making the film denser. The Si–OH and carbon impurities in the oxide film decreased with decreasing TEOS/O2. Current–voltage and capacitance–voltage characteristics were measured for oxide films deposited on silicon wafers. The leakage current density, the interface trap density, and flatband voltage shift were decreased and it was confirmed that high quality silicon dioxide films were obtained at near room temperature with CPECVD along with intermediate O2 plasma treatment.
Combinatorial methodologies offer potential for rapid research of photoresist materials and formulations
Authors: Lenhart Joseph L. , Jones Ronald L. , Lin Eric K. , Soles Christopher L. , Wu Wen-li , Goldfarb Dario L. , Angelopoulos Marie
Published: July 2002

A combinatorial research methodology is outlined with the potential to investigate material factors in photoresist formulations more rapidly than with traditional experimental design. The approach involves generating a gradient of processing variables in the photoresist film and using a set of analysis tools to “map” the photoresist properties as a function of the gradient variables. While high-throughput strategies have proven useful for empirical optimization of photoresist processing conditions, they have not been fully exploited to probe the complex array of material issues in projection lithography. Of primary importance in combinatorial methodologies is the generation of variable gradients. The focus of this article is to illustrate techniques to generate a gradient in bake temperature and bake time in the polymer films, and to illustrate that these gradient techniques can be used to probe fundamental properties of lithographic materials, such as deprotection kinetics. These gradient techniques were applied to rapidly probe the deprotection behavior of a poly(tertbutyloxy-carbonyloxy-styrene). The deprotection data, obtained by applying the combinatorial gradients, agrees well with previous literature, validating the accuracy of these high throughput methods. The advantage of the combinatorial research strategies lies in the potential to investigate fundamental lithographic phenomena more rapidly than with traditional experimentation.
Angular distribution of molecular beams from modified Knudsen cells for molecular-beam epitaxy
Authors: Shen L. Y. L.
Published: July 2002

The molecular-beam epitaxy (MBE) method is an important tool which can provide new and different types of semiconductor films. The effusion ovens used in MBE studies were not an ideal Knudsen-type design that had employed small orifices. We have measured the beam intensity distribution of an effusion oven that had 240 small channels. Applying the theory of Clausing, who derived the angular distribution from a small hole of radius r and length L, and using the superposition principle, we have compared the calculation with experimental data and found good agreement. Intensity distributions from an oven with a single large opening are also measured. This geometry cannot be calculated but actually provides a useful method of collimating molecular beams.
X-ray lithography source using a stationary solid Pd target
Authors: Maldonado J. R. , Poulsen M. E. , Saunders T. E. , Vratny F. , Zacharias A.
Published: July 2002

This paper describes a relatively high power density (10–15 kW/cm2) x-ray source for x-ray lithography applications. The source utilizes a stationary solid Pd target cooled by a high velocity water flow. This source has been operated for several months in a shop environment. No degradation in performance has been observed.
Changes induced on the surfaces of small Pd clusters by the thermal desorption of CO
Authors: Doering D. L. , Poppa H. , Dickinson J. T.
Published: July 2002

The stability and adsorption/desorption properties of supported Pd crystallites less than 5 nm in size were studied by Auger electron spectroscopy and repeated flash thermal desorption of CO. The Pd particles were grown epitaxially on heat-treated, UHV-cleaved mica at a substrate temperature of 300°C and a Pd impingement flux of 4×1013 atoms/cm2 s. Auger analysis allowed in situ measurement of relative particle disperion and contamination, while FTD monitored the CO desorption properties. The results show that significant changes in the adsorption properties can easily be detected. Changes in the Pd Auger signal and the desorption spectrum during the first few thermal cycles are believed to be due to particle coalescence and facetting. The rate of this change is dependent on the temperature and duration of the desorption. Significant reductions in the amplitude of the desorptions peak occur during successive CO desorptions are attributed to increases of surface carbon, induced by the desorption of CO (an effect not observed on large single crystals). The contamination process could be reversed by heat treatment in oxygen or hydrogen.
Measurement of H2, D2 solubilities in Zr–Al
Authors: Knize R. J. , Cecchi J. L. , Dylla H. F.
Published: July 2002

We have measured solubility constants for hydrogen and deuterium in the Zr–Al alloy to be: KH = exp [11.1(5)−16900(600)/T] [Torr/(Torr⋅1/g)2] and KD = exp [12.2(8)−16800(600)/T] [Torr/(Torr⋅1/g)2], respectively, where K is defined implicitly by P = Kq2 with P the equilibrium pressure (in Torr) and q the bulk concentration (in Torr⋅l/g). These values, in conjunction with a model for the solubility, predict that the constant for tritium, KT ∠4KH. Consequently, the regeneration of tritium will be faster by a factor of 4 over that for hydrogen at the same temperature, or the tritium regeneration temperature can be reduced∠50 K compared to hydrogen for the same regeneration time.
Patterning of poly-para-xylylenes by reactive ion etching
Authors: Yeh J. T. C. , Grebe K. R.
Published: July 2002

Poly-para-xylylene family thin films deposited by vapor phase polymerization are pin hole free and are chemically inert to most acids, alkalies, and organic solvents. These properties make this material very attractive as a passivation agent on top of devices. This paper discusses the patterning of such films on planar structures by various masking techniques and the reactive ion etching (RIE) of the poly(monochloro-p-xylylene) in an oxygen-containing plasma, including details like etch rates, control of edge profiles (vertical or tapered), and the process parameters to achieve patterns of 1.5 μm wide and below.
A simple, controllable source for dosing molecular halogens in UHV
Authors: Spencer N. D. , Goddard P. J. , Davies P. W. , Kitson M. , Lambert R. M.
Published: July 2002

An electrochemical source for the reproducible generation and dosing of halogens in UHV systems is described. This approach minimizes corrosion damage to vacuum hardware and lends itself to the study of both submonolayer and multilayer halogen adsorption. The corrosive action of halogens on ultrahigh vacuum components has necessitated the development of molecular halogen beam sources, which allow in situ generation and dosing of fluorine, chlorine, bromine, and iodine, with a negligible increase in vacuum chamber background pressure. This communication describes the chlorine and bromine sources developed and routinely used in our laboratory. Iodine dosing may be accomplished using a source of similar design. Fluorine, however, because of its highly reactive nature, requires a somewhat different design of source, such as that recently described in detail by Bechtold.1
Raman spectroscopy of silicide formation at the Pt/crystalline Si interface
Authors: Tsang J. C. , Matz R. , Yokota Y. , Rubloff G. W.
Published: July 2002

Raman spectroscopy has been used to characterize the formation of Pt-silicide on the Si(100) and (111) surfaces. 5–200 Å Pt overlayers were deposited on atomically clean Si surfaces, reacted and studied by photoemission, Auger spectroscopy and transmission electron microscopy (TEM). The Raman spectra were obtained with a multichannel Raman system; this allowed direct measurements of very thin overlayers on crystalline surfaces. For interfaces reacted at T>300 °C, the Raman spectra showed new lines; the strongest at 82 and 140 cm−1. These are assigned to PtSi by correlation with the TEM phase identification. The relative intensities of the PtSi Raman lines depend on the Pt thickness and the Si substrate orientation. For T<200 °C, these features are broadened and weaker, suggesting a limited (incomplete) reaction. This is consistent with the electron spectroscopy and TEM measurements on these samples. Our measurements show Raman spectroscopy can be used for silicide interface studies to identify and characterize (without extra sample preparation) thin reacted layers, even at the buried interface between unreacted metal and crystalline Si.