[en] This Thesis presents measurements of the decays B^- → Ξ_c⁰(bar Λ)_c^-, (bar B)⁰ → Ξ_c⁺(bar Λ)_c^-, B^- → Λ_c⁺(bar Λ)_c^- K^-, and (bar B)⁰ → Λ_c⁺(bar Λ)_c^- K_s⁰ based on 228 million Υ(4S) → B(bar B) decays collected with the BABAR detector at the SLAC PEP-II asymmetric-energy B factory.

[en] Purpose: Visualization and processing of medical images and radiation treatment plan evaluation have traditionally been constrained to local workstations with limited computation power and ability of data sharing and software update. We present a web-based image processing and planning evaluation platform (WIPPEP) for radiotherapy applications with high efficiency, ubiquitous web access, and real-time data sharing. Methods: This software platform consists of three parts: web server, image server and computation server. Each independent server communicates with each other through HTTP requests. The web server is the key component that provides visualizations and user interface through front-end web browsers and relay information to the backend to process user requests. The image server serves as a PACS system. The computation server performs the actual image processing and dose calculation. The web server backend is developed using Java Servlets and the frontend is developed using HTML5, Javascript, and jQuery. The image server is based on open source DCME4CHEE PACS system. The computation server can be written in any programming language as long as it can send/receive HTTP requests. Our computation server was implemented in Delphi, Python and PHP, which can process data directly or via a C++ program DLL. Results: This software platform is running on a 32-core CPU server virtually hosting the web server, image server, and computation servers separately. Users can visit our internal website with Chrome browser, select a specific patient, visualize image and RT structures belonging to this patient and perform image segmentation running Delphi computation server and Monte Carlo dose calculation on Python or PHP computation server. Conclusion: We have developed a webbased image processing and plan evaluation platform prototype for radiotherapy. This system has clearly demonstrated the feasibility of performing image processing and plan evaluation platform through a web browser and exhibited potential for future cloud based radiotherapy

[en] The formation of volatile organic compounds (VOCs), such as methanol, in kraft mills has been an environmental concern. Methanol is soluble in water and can increase the biochemical oxygen demand. Furthermore, it can also be released into atmosphere at the process temperatures of kraft mill-streams. The Cluster Rule of the EPA now requires the control of the release of methanol in pulp and paper mills. This research program was conducted to develop a computer simulation tool for mills to predict VOC air emissions. To achieve the objective of the research program, much effort was made in the development of analytical techniques for the analysis of VOC and determination of vapor liquid partitioning coefficient of VOCs in kraft mill-streams using headspace gas chromatography. With the developed analytical tool, methanol formation in alkaline pulping was studied in laboratory to provide benchmark data of the amount of methanol formation in pulping in kraft mills and for the validation of VOC formation and vapor-liquid equilibrium submodels. Several millwide air and liquid samplings were conducted using the analytical tools developed to validate the simulation tool. The VOC predictive simulation model was developed based on the basic chemical engineering concepts, i.e., reaction kinetics, vapor liquid equilibrium, combined with computerized mass and energy balances. Four kraft mill case studies (a continuous digester, two brownstock washing lines, and a pre-evaporator system) are presented and compared with mill measurements. These case studies provide valuable, technical information for issues related to MACT I and MACT II compliance, such as condensate collection and Clean-Condensate-Alternatives (CCA)

[en] A DFT study using B3LYP/6-311+G(3df,2p) method, has been performed to investigate the total energies, equilibrium geometries, bonding energies, and the values of spin contamination of BX and XBBX molecules, where X=CO, CS, N/sub 2/, CNCH/sub 3/, H/sub 2/O, H/sub 2/S, NH/sub 3/, PH/sub 3/, C/sub 5/H/sub 5/N, F-, CN-, NO/sub 2/-. NBO analysis calculations also obtain the natural charges and bond orders at B3LYP/6-311+G(3df,2p) level. The quadruplet is ground state for both CO and CS ligands, by dimer of which can form stable singlet of XBBX. But for the remaining ligands, the doublets are ground states, contrary to the BCO and BCS systems. (author)

[en] Radial power distribution is important for temperature distribution calculations in fuel rod performance simulation code. In order to reconstruct the radial power profiles in one model for different types of fuel, such as UO₂, MOX, UO₂-Gd₂O₃, integral fuel burnable absorber(IFBA), etc., this paper proposes a new radial power distribution construction model. Compared with traditional radial power distribution interpolation method which is based on All Parameters Separated way (APS), the new RPD reconstruction method in this paper, called Partial Parameters Separated method (PPS), only use few transient parameters to construct the RPD by interpolation. PPS method has been used in fuel thermal-mechanical analysis code FUPAC. The numerical results show that PPS model can be used to reconstruct RPD for UO₂, UO₂-Gd₂O₃, IFBA fuel rods, and has an excellent precision. The PPS method, which not only can be used in current PWR's fuel, but also used in new type fuel, such as ATF, has a good validity and practicability. (author)

[en] In this paper, we will review both past and recent progresses in the generation, detection and application of intense terahertz (THz) radiation. We will restrict the review to laser based intense few-cycle THz sources, and thus will not include sources such as synchrotron-based or narrowband sources. We will first review the various methods used for generating intense THz radiation, including photoconductive antennas (PCAs), optical rectification sources (especially the tilted-pulse-front lithium niobate source and the DAST source, but also those using other crystals), air plasma THz sources and relativistic laser–plasma sources. Next, we will give a brief introduction on the common methods for coherent THz detection techniques (namely the PCA technique and the electro-optic sampling), and point out the limitations of these techniques for measuring intense THz radiation. We will then review three techniques that are highly suited for detecting intense THz radiation, namely the air breakdown coherent detection technique, various single-shot THz detection techniques, and the spectral-domain interferometry technique. Finally, we will give an overview of the various applications that have been made possible with such intense THz sources, including nonlinear THz spectroscopy of condensed matter (optical-pump/THz-probe, THz-pump/THz-probe, THz-pump/optical-probe), nonlinear THz optics, resonant and non-resonant control of material (such as switching of superconductivity, magnetic and polarization switching) and controlling the nonlinear response of metamaterials. We will also provide a short perspective on the future of intense THz sources and their applications. (topical review)

[en] The Method of Characteristics (MOC) which can calculate arbitrary geometry neutron transport equation becomes more and more popular and is adopted in many neutron transport codes. However, the MOC codes with Flat Source Approximation (FSA) needs large storage space and long computing time when calculating large-scale three dimensional neutron transport problems. This paper proposes a new source approximation called Linear Source Approximation (LSA). By calculating several three dimensional neutron transport problems using the codes with FSA and LSA respectively, it was shown that the LSA MOC code gets more accurate results than the FSA MOC code with the same spatial meshes, and that the LSA MOC code with large meshes can get the results with the same accuracy of the FSA MOC code with fine spatial meshes. By using large spatial meshes which means there are less meshes and ray trajectories to store in memory, the LSA MOC code can calculate the three dimensional neutron transport problems with less storage and shorter computing time than FSA MOC code with fine meshes. Therefore, it is concluded that LSA MOC with large spatial meshes is able to calculate large-scale three dimensional problems with reasonable storage space and computing time. (authors)

[en] The tabular representation of few-group cross section is widely used for node wise two-step core simulations. However, it may take too much memory usage for pin-by-pin two-step simulations. A few-group cross section representation method for PWR has been developed to reduce memory usage in this paper. The few-group cross sections are represented as the sum of a base term and a collection of partial terms. Each of these terms is fitted by modified model tree. The case matrix of training data set is similar with that of the conventional methods such as the piece wise interpolation and the tabular representation. Two modifications have been made for the model tree algorithm: 1) burnup is the only variable to split data set, 2) linear regression method on nodes of the tree is replaced with polynomial fitting method according to priori knowledge of the relationship between cross sections and state variables. Through the modifications accuracy and generalization ability are achieved without the pruning procedure. Then the lattice calculations for test data set could be canceled. Tests on the typical PWR lattice are performed. Numerical results show that for the worst case the memory usage of this method is less than 30% of the tabular representation, when the maximum error of reactivity is less than 500 pcm. The memory usage for other cross sections is less than 10% with high accuracy. Optimization of the target tolerance criteria should be tested for fast group cross sections. Large errors in thermal group absorption and fission production cross sections lead to large errors in Kin f and it needs more study on regression model. The method combined with the tabular representation might be more suitable for the pin-by-pin two-step simulations. (author)

[en] Fracture functions are parton distributions of an initial hadron in the presence of an almost collinear particle observed in the final state. They are important ingredients in QCD factorization for processes where a particle is produced diffractively. There are different fracture functions for a process in different kinematic regions. We take the production of a lepton pair combined with a diffractively produced particle in hadron collisions to discuss this. Those fracture functions can be factorized further if there are large energy scales involved. We perform one-loop calculations to illustrate the factorization in the case with the diffractively produced particle as a real photon. Evolution equations of different fracture functions are derived from our explicit calculations. They agree with expectations. These equations can be used for resummations of large log terms in perturbative expansions.

[en] KYCORE is a 3-D direct reactor calculation code capable of performing reactor heterogeneous calculation without cross section homogenization and group condense. It is developed in Nuclear Power Institute of China, involving radial characteristics method (MOC) and axial discrete ordinate method (Sn) coupled 3-D neutron transport and subgroup method with fixed source problem for resonance treatment and depletion, aiming at providing mini core design and commercial reactor benchmark solution. This article briefly introduces optimized MOC/Sn coupling, adjusted coarse mesh finite difference (CMFD) and resonance treatment. The accuracy of the code is verified with 3-D VERA Problem 3 benchmark and proves to be credible. (author)