Digital Commons Network^™

Highest-Quality Modes In Disordered Photonic Crystals, Alexey Yamilov, Hui Cao

Physics Faculty Research & Creative Works

We studied the modes of the highest-quality factor Qm in disordered photonic crystals. by varying the strength of disorder, we identified five different scaling regimes of the ensemble averaged (Qm) with the system size. For sufficiently large systems, (Qm) reaches the maximum at some finite degree of disorder, where its value is comparable to the quality factor of an intentionally introduced single defect at the center of a photonic band gap. Near this optimal degree of disorder, we predict a superexponential increase of (Qm) with the system size, due to migration of the frequencies of the highest-quality modes toward the …

Kinetics Of Binary Nucleation Of Vapors In Size And Composition Space, Sergey P. Fisenko, Gerald Wilemski

Physics Faculty Research & Creative Works

We reformulate the kinetic description of binary nucleation in the gas phase using two natural independent variables: the total number of molecules g and the molar composition x of the cluster. The resulting kinetic equation can be viewed as a two-dimensional Fokker-Planck equation describing the simultaneous Brownian motion of the clusters in size and composition space. Explicit expressions for the Brownian diffusion coefficients in cluster size and composition space are obtained. For characterization of binary nucleation in gases three criteria are established. These criteria establish the relative importance of the rate processes in cluster size and composition space for different …

Order-Parameter Symmetry And Mode-Coupling Effects At Dirty Superconducting Quantum Phase Transitions, Rastko Sknepnek, Thomas Vojta, Rajesh Narayanan

Physics Faculty Research & Creative Works

We derive an order-parameter field theory for a quantum phase transition between a disordered metal and an exotic (non- s -wave) superconductor. Mode coupling effects between the order parameter and other fermionic soft modes lead to an effective long-range interaction between the anomalous density fluctuations which is reflected in singularities in the free energy functional. However, this long-range interaction is not strong enough to suppress disorder fluctuations. The asymptotic critical region is characterized by run-away flow to large disorder. For weak coupling, this asymptotic region is very narrow. It is preempted by a wide crossover regime with mean-field critical behavior …

Smeared Phase Transition In A Three-Dimensional Ising Model With Planar Defects: Monte Carlo Simulations, Rastko Sknepnek, Thomas Vojta

Physics Faculty Research & Creative Works

We present results of large-scale Monte Carlo simulations for a three-dimensional Ising model with short-range interactions and planar defects, i.e., disorder perfectly correlated in two dimensions. We show that the phase transition in this system is smeared, i.e., there is no single critical temperature, but different parts of the system order at different temperatures. This is caused by effects similar to but stronger than Griffiths phenomena. In an infinite-size sample there is an exponentially small but finite probability to find an arbitrary large region devoid of impurities. Such a rare region can develop true long-range order while the bulk system …

Study Of Structural And Magnetic Properties Of Iron-Rich Mixed Rare-Earth Nddyfe (17-Y-X)Coxsiy Compounds, Kishore Kamaraju, Jinbo Yang, William B. Yelon, Oran Allan Pringle, M. S. Kim, Qingsheng Cai, William Joseph James

Physics Faculty Research & Creative Works

A series of NdDyFe(17-y-x)CoxSiy solid solutions with = 2 and 3 and = 0.5 1.0 and 1.5 were prepared by induction melting stoichiometric amounts of high-purity elements. The postannealed samples consist of two phases belonging to the space groups R3 m and P63 mmc . The lattice parameters and the unit cell volumes were calculated from the refinements of the magnetic and structural unit cells using the FULLPROF version of the Rietveld program. For a fixed content of Co, the maximum Curie temperatures (305 C to 405 C) were observed in samples with = 1 and having two phases, a …

Traversal Times For Random Walks On Small-World Networks, V. M. Kenkre, Paul Ernest Parris

Physics Faculty Research & Creative Works

We study the mean traversal time tau for a class of random walks on Newman-Watts small-world networks, in which steps around the edge of the network occur with a transition rate F that is different from the rate f for steps across small-world connections. when f>>F, the mean time tau to traverse the network exhibits a transition associated with percolation of the random graph (i.e., small-world) part of the network, and a collapse of the data onto a universal curve. This transition was not observed in earlier studies in which equal transition rates were assumed for all allowed steps. …

Ultraviolet Photonic Crystal Laser, Alexey Yamilov, Hui Cao, Robert P. H. Chang, Xiaohua Wu, Xang Liu, Shuyou Li, Vinayak P. Dravid

Physics Faculty Research & Creative Works

We fabricated two-dimensional photonic crystal structures in zinc oxide films with focused-ion-beam etching. Lasing is realized in the near-ultraviolet frequency at room temperature under optical pumping. From the measurement of lasing frequency and spatial profile of the lasing modes, as well as the photonic band structure calculation, we conclude that lasing occurs in the strongly localized defect modes near the edges of photonic band gap. These defect modes originate from the structure disorder unintentionally introduced during the fabrication process. ©2004 American Institute of Physics

Variational Considerations In The Study Of Carrier Transport In Organic Crystals, V. M. Kenkre, Paul Ernest Parris

Physics Faculty Research & Creative Works

A variational approach is used to investigate consequences of electron-phonon interactions between a charge carrier and multiple (specifically two) phonon branches. Phase diagrams are obtained and the nature of the transition from undressed to dressed phases of the carrier is studied with their help. No sharp transition between singly dressed and doubly dressed phases occurs. The effective carrier bandwidth, reduced by strong coupling to the high-frequency branch is found to be stable with respect to small to intermediate values of additional coupling to the low-frequency branch. This finding lends support to transport calculations based on the idea that carriers in …

Forced Patriot Acts, Alan K. Chen

Denver Law Review

No abstract provided.

Optical Characterization Of Ceramic Thin Films: Applications In Low-Temperature Solid Oxide Fuel-Cell Materials Research, B. P. Gorman, V. Petrovsky, Harlan U. Anderson, T. Petrovsky

Materials Science and Engineering Faculty Research & Creative Works

Characterization of thin film solid oxide fuel-cell materials can be difficult due to the range of porosities in electrodes and electrolytes as well as the nano-sized pores and particles. in this study, optical characterization techniques such as ultraviolet-visible transmission and reflection spectrophotometry are illustrated as methods for achieving information about the film density from the film refractive index as well as the film thickness. These techniques were used to investigate the sintering process of colloidal CeO₂ on sapphire substrates and polymeric precursor-derived ZrO₂:16%Y (YSZ) thin films on silicon over the temperature range 400-1000 °C, and the results …

Asymmetry Of Above-Threshold Ionization Of Metal Clusters In Two-Color Laser Fields: A Time-Dependent Density-Functional Study, H. S. Nguyen, A. D. Bandrauk, Carsten A. Ullrich

Physics Faculty Research & Creative Works

A spherical jellium model and time-dependent density functional theory for two-color ultrashort laser pulses as a function of phase difference between two fields were used to calculate the above threshold ionization (ATI) spectra of small metal clusters. ATI spectra and the ionized electrons fluxes were obtained in the two opposite directions of the linearly polarized laser fields. It is found that ATI spectra has long energy plateaus, with cutoffs up to 30-40 times the ponderomotive energy Up. However, no extended plateaus were observed in high-harmonic generation spectra.

The Influence Of Biology And Commitment Beliefs On Jealousy Responses, Rebecca L. Ammon

All Volumes (2001-2008)

Research on biological sex differences in romantic jealousy suggests that males are more upset by sexual infidelity and females are more upset by emotional infidelity. Researchers identify two types of jealousy (i.e., sexual and emotional) and two types of commitment (i.e., sexual exclusivity and relational duration). The type of jealousy experienced may be a rational or emotional response to different commitment beliefs rather than dependent on biological sex. A sample of 230 college students completed various measures of commitment and jealousy as part of an online survey. People who valued sexually exclusive relationships were more distressed by sexual infidelity. People …

Influence Of Solar Luminosity Over Geomagnetic And Climatic Cycles As Derived From Speleothems, Y. Shopov, D. Stoykova, L. Tsankov, M. Sanabria, D. Georgieva, D. Ford, L. Georgiev

International Journal of Speleology

We observed cycles presented in a luminescent solar insolation proxy record from a speleothem from Jewel Cave, South Dakota, US. We found cycles of orbital precession with periods of 23 and 19 ka and of obliquity of 41 ka and many others from non-orbital origin in this sample. We determined the Solar origin of the cycles with durations of 11500, 4400, 3950, 2770, 2500, 2090, 1960, 1670, 1460, 1280, 1195, 1145, 1034, 935, 835, 750 and 610 years. It was done by their detection both in proxy records of speleothem luminescence, Δ¹⁴C and the intensity of the geomagnetic …

Assessing The Legality Of Invading Iraq, Sean D. Murphy

GW Law Faculty Publications & Other Works

The recent invasion of Iraq challenges a cornerstone of contemporary international law: the prohibition on the use of force by one state against another state. The conventional wisdom is that the United States embarked on the invasion with little regard for international law or for the attitudes reflected by other nations, including the other members of the UN Security Council. This article disputes that conventional wisdom.

First, the Bush administration could have ignored international law and the Security Council, but in fact deployed a fairly sophisticated legal theory as to why U.S. actions were permissible under international law, a theory …

'But I Thought He Had A Gun' - Race And Police Use Of Deadly Force, Cynthia Lee

GW Law Faculty Publications & Other Works

It is undisputed that Blacks are disproportionately represented among the victims of police shootings. In a comprehensive review of the literature on police use of deadly force, James Fyfe reports that every study that has examined this issue [has] found that blacks are represented disproportionately among those at the wrong end of police guns. Although Blacks represent approximately 13 percent of the population in the United States, in parts of the country they constitute 60 to 85 percent of the victims of police shootings. On average, Blacks are more than six times as likely as Whites to be shot by …

The Challenge Of Cooperative Regulatory Relations After Enlargement, Francesca Bignami

GW Law Faculty Publications & Other Works

This paper conceptualises European governance as a continuous series of collective action games among national regulators. European administration is theorized as a set of mutually beneficial relations among independent regulators, rather than as a hierarchy of supranational institutions, courts, and national administrators. The collective action approach highlights the importance of certain factors in fostering regulatory cooperation and enabling the common market to become an administrative reality: repeated interactions, monitoring and sanctioning by the Commission and the courts, reciprocity norms, and trust. It also suggests that one of the most significant challenges of enlargement will be to establish cooperative regulatory exchanges …

How Lawyers Compete, Michael B. Abramowicz

GW Law Faculty Publications & Other Works

Lester Brickman's article establishes that the market for contingent fee lawyers is unusual, perhaps even bizarre. By removing legal impediments to the solicitation of clients, by unleashing the capital markets to finance legal claims, and by allowing intermediaries to match client and counsel, we could produce competition. Brickman has convinced me that there is little competition in contingency fee markets, and that such markets could be much more competitive. But I am not sure there is as little competition as he thinks, or that the changes in legal regimes he proposes would be sufficient to make the markets more competitive.

Phylogeny And Biogeography Of Wajira (Leguminosae): A Monophyletic Segregate Of Vigna Centered In The Horn Of Africa Region, Mats Thulin, Matt Lavin, Remy Pasquet, Alfonso Delgado-Salinas

All Peer-Reviewed Publications

Evidence from chloroplast trnK and nuclear ribosomal ITS sequences and morphological data reveals that the monotypic legume genus Wajira is nested within a clade comprising the species of Vigna subgen. Macrorhynchus. This Wajira-containing clade is basally branching in a larger clade that contains many of the genera traditionally referred to as tribe Phaseoleae subtribe Phaseolinae. Wajira is thus recircumscribed to include Vigna subgen. Macrorhynchus. Given the heterogeneity of floral morphology of its constituent species, Wajira is apomorphically diagnosed by woody stems and a pollen brush that comprises an introrse linear array of unicellular hairs. This recircumscribed genus now comprises five …

Social Trust, Cooperation, And Human Capital, Fali Huang

Research Collection School Of Economics

The importance of social trust on economic growth has been suggested by many empirical works. This paper formalizes the concept of social trust and studies its formation process in a game theoretic setting. It provides plausible explanations for a wide range of empirical and experimental findings. The main results of the paper are as follows. For utility-maximizing players, cooperation arises in one-period prisoner’s dilemmas if and only if there is social trust. The amount of social trust in a given game is determined by the distribution of players’ cooperative tendency. Cooperative tendency is in essence a component of human capital …

Congestion Control And Vehicle Ownership Restriction: The Choice Of An Optimal Quota Policy, Winston T. H. Koh

Research Collection School Of Economics

Singapore introduced a vehicle quota system (VQS) in 1990 as part of its overall policy to control urban congestion. While the VQS has reduced the annual growth rate of the vehicle population to about 3 per cent, it has created uncertainty in the cost of vehicle ownership due to the fluctuations in licence prices. This paper discusses three issues relating to the optimal design of a VQS: licence transferability, sub-categorisation, and the choice of an auction format. The analysis shows that licence transferability is not unambiguously desirable, sub-categorisation is highly regressive, and an open auction format results in less aggressive …

Forecasting The Global Electronics Cycle With Leading Indicators: A Var Approach, Hwee Kwan Chow, Keen Meng Choy

Research Collection School Of Economics

Developments in the global electronics industry are typically monitored by tracking indicators that span a whole spectrum of activities in the sector. However, these indicators invariably give mixed signals at each point in time, thereby hampering attempts at prediction. In this paper, we propose a unified framework for forecasting the global electronics cycle by constructing a VAR model that captures the economic interactions between putative leading indicators representing expectations, orders, inventories and prices. The ability of the indicators to presage world semiconductor sales is first examined by Granger causality tests. Subsequently, an impulse response analysis confirms the leading qualities of …

A Small-Sample Overlapping Variance-Ratio Test, Yiu Kuen Tse, K. W. Ng, Xibin Zhang

Research Collection School Of Economics

The null distribution of the overlapping variance-ratio (OVR) test of the random-walk hypothesis is known to be downward biased and skewed to the right in small samples. As shown by , the test under-rejects the null on the left tail seriously when the sample size is small. This property adversely affects the applicability of the OVR test to macroeconomic time series, which usually have rather small samples. In this paper, we propose a modified overlapping variance-ratio statistic and derive its exact mean under the normality assumption. We propose to approximate the small-sample distribution of the modified statistic using a beta …

Empirical Characteristic Function Estimation And Its Applications, Jun Yu

Research Collection School Of Economics

This paper reviews the method of model-fitting via the empirical characteristic function. The advantage of using this procedure is that one can avoid difficulties inherent in calculating or maximizing the likelihood function. Thus it is a desirable estimation method when the maximum likelihood approach encounters difficulties but the characteristic function has a tractable expression. The basic idea of the empirical characteristic function method is to match the characteristic function derived from the model and the empirical characteristic function obtained from data. Ideas are illustrated by using the methodology to estimate a diffusion model that includes a self-exciting jump component. A …

Selection Correction And Sensitivity Analysis For Ordered Treatment Effect On Count Response, Myoung-Jae Lee

Research Collection School Of Economics

In estimating the effect of an ordered treatment [tau] on a count response y with an observational data where [tau] is self-selected (not randomized), observed variables x and unobserved variables [epsilon] can be unbalanced across the control group ([tau] = 0) and the treatment groups ([tau] = 1, . . . , J). While the imbalance in x causes 'overt bias' which can be removed by controlling for x, the imbalance in [epsilon] causes 'covert (hidden or selection) bias' which cannot be easily removed. This paper makes three contributions. First, a proper counter-factual causal framework for ordered treatment effect on …

Market Segmentation And Information Values Of Earnings Announcements: Some Empirical Evidence From An Event Study On The Chinese Stock Market, Y. Gao, Yiu Kuen Tse

Research Collection School Of Economics

This paper investigates the trading activities of two distinct classes of shareholders, namely, the Chinese domestic investors and the foreign investors in the segmented Chinese A- and B-share markets, respectively. We conduct an event study on the annual earnings announcements based on two different accounting standards: International accounting standards (IAS) and PRC generally accepted accounting principles (PRC GAAP). The earnings announcements based on IAS and PRC GAAP are value relevant. The investors in the B-share market react to both the IAS and PRC GAAP earnings announcements, while the investors in the A-share market pay more attention to the PRC GAAP …

Peri-Operative Management Of A Patient With Uncontrolled Polycythemia Vera For Above Knee Amputation, A Ahmed, K A. Shah

Department of Anaesthesia

No abstract provided.

The Essential Components Of An Efficacious Web Site For The Recruitment And Retention Of Stellar Graduate Students, Margaret Laracy Smolin

Seton Hall University Dissertations and Theses (ETDs)

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Marketing Potential Of Thai Food And Products In The U.S. Market, Athitaya Vudhikarmrusa

Seton Hall University Dissertations and Theses (ETDs)

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Oil Pollution Liability And Control Under International Maritime Law, Michael A. De Gennaro

Vanderbilt Journal of Transnational Law

Oil spills on the world's oceans and waterways are a significant environmental threats. This Note explores some of the myriad reasons why the law--in both the United States and the international community--has failed adequately to address many of the reasons spills occur in the first instance.

Beginning with a brief history of various pollution control schemes enacted over the past few years, this Note focuses on why the current international legal regimes remain ineffective in combating oil pollution. In essence, this Note argues that the current laws fail because of textual deficiencies, a failure to address the external economic realities …

The Thin State In Thick Globalism: Sovereignty In The Information Age, Adeno Addis

Vanderbilt Journal of Transnational Law

Looking at the astonishing technological developments in mass communication over the past several decades, Professor Addis explores whether and how the resulting communication revolution has undermined the notion of territorial sovereignty. Specifically, he argues that (1) although the territorial state has faced serious challenges from the communication revolution, the question is not whether state sovereignty will survive, but how thick or thin that sovereignty will (or should) be; (2) even if it were true that the territorial state is giving way to other institutional arrangements, those arrangements may not be a decentralized system of governance in that the communication revolution …