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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Quantification of Anthropogenic and Natural Sources of Fine Particles in Houston, Texas Using Positive Matrix Factorization

Peña Sanchez, Carlos Alberto 08 1900 (has links)
Texas, due to its geographical area, population, and economy is home to a variety of industrialized areas that have significant air quality problems. These urban areas are affected by elevated levels of fine particulate matter (PM2.5). The primary objective of this study was to identify and quantify local and regional sources of air pollution affecting the city of Houston, Texas. Positive Matrix Factorization (PMF) techniques were applied to observational datasets from two urban air quality monitoring sites in Houston from 2003 through 2008 in order to apportion sources of pollutants affecting the study region. Data from 68 species for Aldine and 91 for Deer Park were collected, evaluated, and revised to create concentration and uncertainty input files for the PMF2 and EPA PMF (PMF3) source apportionment models. A 11-sources solution for Aldine and 10-sources for Deer Park were identified as the optimal solutions with both models. The dominant contributors of fine particulate matter in these sites were found to be biomass burnings (2%-8.9%), secondary sulfates I (21.3%-7.6%) and II (38.8%-22.2%), crustal dust (8.9%-10.9%), industrial activities (10.9%-4.2%), traffic (23.1%-15.6%), secondary nitrates (4.4%-5.5%), fresh (1%-1.6%) and aged(5.1%-4.6%) sea salt and refineries (1.3%-0.6%), representing a strong case to confirm the high influence of local activities from the industrial area and the ship channel around the Houston channel. Additionally, potential source contribution function (PSCF) and conditional probability function (CPF) analyses were performed to identify local and regional source-rich areas affecting this urban airshed during the study period. Similarly, seasonal variations and patterns of the apportioned sources were also studied in detail.
52

The Photoproduction of Strangeness in ΓP → ΛK+Π+Π− with CLAS at Jefferson Lab

Unknown Date (has links)
The available information about strange excited mesons is limited and most of the observed states have been reported but not confirmed. While the low mass region (1.0 - 1.5 GeV) has been extensively studied in the past and states such as the K1(1270), K1(1400), and K*(1410) have been confirmed by a handful of experiments, little is known about the spin-parity structure of resonances in the higher K+ π+ π- mass region (1.5-2.0 GeV). Past experiments have used hadron beams to gain access to the K+ π+ π- system, and have provided extensive information about strange states that made mapping their spectrum possible. Except for the K*(892), none of the excited strange states has been photoproduced before. We perform a partial wave analysis on a photoproduced K+ π+ π- system produced off a Λ baryon using the CLAS detector at Jefferson Lab. Using a photon beam incident of a liquid hydrogen target, we are able to reconstruct 16K events of the γ p -> Λ K+ π+ π- topology. Results from initial data selection confirmed the dominance of two decay modes for a K+ π+ π- resonance: the K*(892)π+ and the ρ(770)K+. A PWA was carried out in the helicity formalism using the reflectivity basis in the isobar model to parametrize the decay amplitudes of the resonances. Resonating structures are found in the 1+S wave primarily coupling to K*(892)π+ with a mass of 1.35 GeV/c2 and to ρ(770)K with a lower mass structure around 1.33 GeV/c2 and a higher mass resonance around 1.73 GeV/c2. The 1-P also exhibited a significant resonating behavior with a mass of 1.43 GeV/c2 coupling primarily to the K*(892)π+ decay mode. Also observed, an enhancement around 1.49 GeV/c2 in the 2+D wave strongly coupling to K*2 (1430)π+, and an enhancement in the 2-S wave around 1.76 GeV/c2 coupling primarily to K*2 (1430)π+. / A Dissertation submitted to the Department of Physics in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Spring Semester 2016. / April 11, 2016. / Data Analysis, Hadrons, KPiPi, Particle Physics, Photoproduction, PWA / Includes bibliographical references. / Paul Eugenio, Professor Directing Dissertation; James Justus, University Representative; Volker Crede, Committee Member; Simon Capstick, Committee Member; Alexander Ostrovidov, Committee Member; Horst Wahl, Committee Member.
53

粤語複合助詞的研究: A study on the compound particles in Cantonese. / Study on the compound particles in Cantonese / Yue yu fu he zhu ci de yan jiu: A study on the compound particles in Cantonese.

January 2014 (has links)
粤語的句末助詞相當豐富,能表達時間、焦點、語氣等多種意義,在過去曾引起廣泛的討論。在日常話語中,助詞往往可以多個連用,它們在句法上處於不同的層次,連用時,是一層一層的疊加。另一點值得注意的是,除了單音節助詞之外,粤語也有一些雙音節的助詞,如「罷啦」(baa2laa1)、「係啦」(hai2laa1),它們整體和前面的句子結合,學者一般認為它們跟助詞連用的情況不同。本文對粤語複合助詞進行了深入的討論,先考察它們的語義功能和語法特點,再探討它們的句法結構,並主張複合助詞是由句法產生的。 / 除了典型的複合助詞「罷啦」和「係啦」之外,本文也把「定啦」(ding2laa1)和「得㗎」(dak1gaa2)分析為複合助詞,四者都由一個謂詞性成分和一個功能性成分組成。在語義上,它們的意義跟其組成成分都有密切的關係,是兩者語義的相加。本文探討了它們的各種語義和用法,並指出它們的一詞多義現象可以透過「行」、「知」、「言」三域的跨域投射理論去解釋。 / 在語法特點方面,複合助詞與前面小句的配搭存在較多的限制;相反,單音節語氣助詞與前面小句的配搭則非常自由,這反映出複合助詞與前面的小句之間存在著一種緊密的關係,可以理解為一種選擇的關係。 / 因此,我們主張複合助詞在句法的深層結構可以分解為〔詞根(謂詞性成分)+詞綴(功能性成分)〕,謂詞性詞根是VP的中心語,選擇小句作為其補足語,通過謂詞性詞根由V到T再到C的移動,與處於T和C的後綴結合成複合助詞,另外,通過小句的移位,推導出表面的語序。 / 透過以上分析,本文對所謂「複合」作出了重新思考,指出「複合」和「連用」的本質其實是一致的。在深層句法結構中,各個成分處於不同的句法層次,一層一層的疊加,分別只在於助詞可以獨用,但複合助詞的謂詞性成分不能脫離後綴獨立使用。此外,本文的討論亦揭示了粤語句末成分由實變虛的可能性。 / Cantonese is renowned for having a rich inventory of sentence final particles which can express a large variety of meanings, such as time, focus and mood, etc. They have attracted a lot of interest in the literature. In daily conversations, particles can be used individually or successively. When they co-occur, they are located at different levels in the syntactic hierarchy. Even more intriguing is that there are some sentence final particles consisting of two or more syllables, which are known as "compound particles", such as baa2laa1 and hai2laa1. Previous studies suggest that they are different from the successive use of particles, because the two or more syllables in a compound particle attach to the preceding clause as a whole. The thesis investigates the semantic meanings and grammatical properties of compound particles. It also explores the syntactic structure of compound particles and argues that they are derived in syntax. / In addition to baa2laa1 and hai2laa1, the thesis considers also ding2laa1 and dak1gaa2 as compound particles. All of them consist of a predicative element and a functional element. Semantically, they are closely related to their components. The thesis demonstrates that different semantic meanings conveyed by a single compound particle are derived by metaphorical projections among various linguistic domains, such as the content, epistemic and speech act domains. / In terms of grammatical properties, the thesis has found that compound particles impose more constraints on the various constituents in the clauses that they are attached to, whereas the combinations of monosyllabic sentence final particles and the preceding clauses are less restricted or almost free. This phenomenon reveals the close relationship between compound particles and their preceding clauses, which can be interpreted as a kind of selectional relation. / For this reason, the thesis proposes that compound particles are decomposed into〔root(predicative element)+ suffix (functional element)〕in the underlying syntactic structure. The predictive element is the head of VP which selects a clause as its complement. The predicative element moves from V to T to C and forms a compound with the suffixes that are located at T and C. The surface word order is derived by further movement of the clause. / From the above analysis, the thesis re-examines the nature of "compound particles" and "successive use of particles". It suggests that they are consistent in their underlying structures with each of the elements occupies the head position of different phrases. The major difference between them is that every particle in a sequence can be used independently, whereas the predicative element in a compound particle cannot be separated from the suffix. Moreover, the thesis reveals the possible grammaticalization of the sentence final elements. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / 黃卓琳. / Thesis (Ph.D.) Chinese University of Hong Kong, 2014. / Includes bibliographical references (leaves 178-183). / Abstracts also in English. / Huang Zhuolin.
54

Induced kinetics of cells and its applications in an opto-electrokinetics chip. / 細胞在光電動晶片內的自發運動及其應用 / CUHK electronic theses & dissertations collection / Xi bao zai guang dian dong jing pian nei de zi fa yun dong ji qi ying yong

January 2013 (has links)
Chau, Long Ho. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 91-97). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts also in Chinese.
55

Delta I Equals Three Halfs Kaon To Two Pion Decays Using Lattice Quantum Chromodynamics with Domain Wall Fermions

Lightman, Matthew January 2011 (has links)
We calculate matrix elements for kaon to two pion decays in the Delta I = 3/2 channel using lattice gauge theory simulations. From these we can extract the decay amplitude A2, for which the real part is related to the decay rate and can be compared to the experimental result Re(A2) = 1.484 x 10^(-8) GeV, and for which the imaginary part is related to direct charge-parity violation in the neutral kaon system. We report the results of one simulation with nearly physical particle masses and kinematics, specifically mK = 509.0(9.1) MeV, mPi = 142.8(2.5) MeV, and EPiPi = 485.7(8.0) MeV. This simulation was performed on RBC/UKQCD 32^3 x 64, Ls = 32 lattices, using 2+1 dynamical flavors of domain wall fermions and a Dislocation Suppressing Determinant Ratio plus Iwasaki gauge action, and with an inverse lattice spacing a^(-1) = 1.373(24) GeV so that the spatial extent of the lattice is 4.60 fm and mPi*L = 3.3. We find that Re(A2) = 1.461(87)stat(200)sys x 10^(-8) GeV, in good agreement with the experimental value. We also find Im(A2) = -8.67(45)stat(1.95)sys x 10^(-13) GeV, and Im(A2)/Re(A2) = -5.93(27)stat(1.42)sys x 10^(-5), however the value of Im(A2) depends on a rough hypothesis for some of the renormalization constants which have not yet been calculated, and thus we quote a large systematic error. We also report the results of a simulation involving a variety of kaon and pion masses and momenta, which was conducted in order to study the dependence of the decay amplitude on particle masses and kinematics, and to study the effect of not having exactly physical masses and kinematics in the first simulation. The use of the quenched approximation and smaller spatial volume in this second simulation allowed for multiple masses to be simulated in a reasonable amount of time, but introduced an uncontrolled approximation and forced us to use pion masses a bit larger than the phys- ical mass. The study was conducted on 24^3 x 64, Ls = 16 lattices, with the quenched Doubly Blocked Wilson 2 gauge action, and an inverse lattice spacing of a^(-1) = 1.31(2) GeV. We find that an extrapolation to physical masses and kinematics yields values Re(A2) = 2.25(18)stat x 10^(-8) GeV and Im(A2) = -13.44(84)stat x 10^(-13) GeV. These results are significantly larger than those of the full dynamical simulation and of experiment. We attribute this mainly to the an inaccurate determination of the lattice spacing a using the rho mass, since it comes in as a^(-3) in the calculation of A2. Finally, a third simulation is performed with 2+1 dynamical flavors of domain wall fermions on a finer 32^3 x 64, Ls = 16 lattice, but only with pions that have nearly zero momentum. It, and the quenched simulation, are used mainly to estimate the systematic error in the first simulation, which is taken as the final result.
56

Search for Excited Randall-Sundrum Gravitons with Semi-Leptonic Diboson Final States in 4.7 fb-1 of Proton-Proton Collisions using the ATLAS Detector at the Large Hadron Collider

Williams, Eric Lloyd January 2012 (has links)
This dissertation describes a search for resonant WW and WZ production in the lvjj decay channel using 4.701 fb-1 of sqrt(s) = 7 TeV LHC collision data collected by the ATLAS detector. Events with a single charged lepton, at least two jets and missing transverse energy are analyzed and no significant deviation from the Standard Model prediction is observed. Upper limits on the production cross section are interpreted as lower limits on the mass of a resonance and are derived assuming two warped extra-dimension production modes: the original Randall-Sundrum (RS1) model and the more recent "bulk" Randal-Sundrum (Bulk RS) model. The mass range for both models is excluded at 95% CL with a lower mass limit for an RS1 graviton of 936 GeV and 714 GeV for the Bulk RS graviton.
57

Searching for Reactor Antineutrino Flavor Oscillations with the Double Chooz Far Detector

Franke, Arthur January 2012 (has links)
This dissertation presents results from a search for reactor antineutrinoₑ flavor oscillations using the Double Chooz Far Detector. The search was performed by observing the rate and energy spectrum of antineutrinoₑ interacting via Inverse Beta Decay in a Gd-doped liquid scintillator detector, and comparing the observation to an expectation based on a prediction of the emitted reactor flux. The Columbia University neutrino group was instrumental in construction of the Double Chooz Outer Veto, as well as the analysis efforts leading to two oscillation measurement results. The most recent analysis is presented herein, focusing on 251.27 days of data (or 33.71 GW-ton-years of exposure). In these data, 8249 IBD candidates were observed, compared to a signal+background prediction of 8936.8. A fit to a two-neutrino oscillation model considering event rate, spectral shape, and time yields a best-fit value of sin² (2θ₁₃) = 0.109 ± 0.030 (stat.) ± 0.025 (syst.) at Δm 2/31 = 2.32 × 10⁻³ eV², with χ²_RS/d.o.f. = 42.1/35. A frequentist method deems the null-oscillation hypothesis excluded by the data at 99.8% C.L., or 2.9σ. These results are in agreement with the measurements of other modern reactor antineutrinoₑ experiments.
58

Precision Lattice Calculation of Kaon Decays with Möbius Domain Wall Fermions

Yin, Hantao January 2013 (has links)
We report our recent development in algorithms and progress in measurements in lattice QCD. The algorithmic development includes the forecasted force gradient integrator, and further theoretical development and implementation of the Möbius domain wall fermions. These new technologies make it practical to simulate large 48^3*96 and 64^3*128 lattice ensembles with (5.5fm)^3 boxes and 140MeV pion. The calculation was performed using the Möbius domain wall fermions and the Iwasaki gauge action. Simulated directly at physical quark masses, these ensembles are of great value for our ongoing and future lattice measurement projects.With the help of measurement techniques such as the eigCG algorithm and the all mode averaging method, we perform a direct, precise lattice calculation of the semileptonic kaon decay K→πlν using these newly generated high quality lattice ensembles. Our main result is the form factor f^+_{Kπ}(q^2) evaluated directly at zero momentum transfer q^2=0. Free of various systematic errors, this new result can be used to determine the CKM matrix element Vus to a very high precision when combined with experimental input. The calculation also provides results for various low energy strong interaction constants such as the pseudoscalar decay constants f_K and f_π, and the neutral kaon mixing matrix element B_K. These calculations are naturally performed by reusing the propagators calculated for the kaon semileptonic decay mentioned above. So they come with no or very low additional cost. The results allow us to also determine these important low energy constants on the lattice to unprecedented accuracy.
59

Precision Lattice Calculation of Kaon Decays with Möbius Domain Wall Fermions

Yin, Hantao January 2013 (has links)
We report our recent development in algorithms and progress in measurements in lattice QCD. The algorithmic development includes the forecasted force gradient integrator, and further theoretical development and implementation of the Möbius domain wall fermions. These new technologies make it practical to simulate large 48^3*96 and 64^3*128 lattice ensembles with (5.5fm)^3 boxes and 140MeV pion. The calculation was performed using the Möbius domain wall fermions and the Iwasaki gauge action. Simulated directly at physical quark masses, these ensembles are of great value for our ongoing and future lattice measurement projects. With the help of measurement techniques such as the eigCG algorithm and the all mode averaging method, we perform a direct, precise lattice calculation of the semileptonic kaon decay K→πlν using these newly generated high quality lattice ensembles. Our main result is the form factor f^+_{Kπ}(q^2) evaluated directly at zero momentum transfer q^2=0. Free of various systematic errors, this new result can be used to determine the CKM matrix element Vus to a very high precision when combined with experimental input. The calculation also provides results for various low energy strong interaction constants such as the pseudoscalar decay constants f_K and f_π, and the neutral kaon mixing matrix element B_K. These calculations are naturally performed by reusing the propagators calculated for the kaon semileptonic decay mentioned above. So they come with no or very low additional cost. The results allow us to also determine these important low energy constants on the lattice to unprecedented accuracy.
60

Precision Search for Muon Antineutrino Disappearance Oscillations Using a Dual Baseline Technique

Cheng, Gary Chia Li January 2013 (has links)
A search for short baseline muon antineutrino disappearance with the SciBooNE and MiniBooNE experiments at Fermi National Accelerator Laboratory in Batavia, Illinois is presented. Short baseline muon antineutrino disappearance measurements help constrain sterile neutrino models. The two detectors observe muon antineutrinos from the same beam, therefore the combined analysis of their data sets serves to partially constrain some of the flux and cross section uncertainties. A likelihood ratio method was used to set a 90% confidence level upper limit on muon antineutrino disappearance that dramatically improves upon prior sterile neutrino oscillation limits in the Δm^2=0.1-100 eV^2 region.

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