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1998

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Articles 1981 - 2010 of 2574

Full-Text Articles in Physical Sciences and Mathematics

Gradient Drift Instability Growth Rates From Global-Scale Modeling Of The Polar Ionosphere, Jan Josef Sojka, M. V. Subramanium, L. Zhu, Robert W. Schunk Jan 1998

Gradient Drift Instability Growth Rates From Global-Scale Modeling Of The Polar Ionosphere, Jan Josef Sojka, M. V. Subramanium, L. Zhu, Robert W. Schunk

All Physics Faculty Publications

The winter polar ionosphere, under southward interplanetary magnetic field (IMF) conditions, experiences irregularity development leading to consequences such as scintillation on transionospheric communication links. These irregularities are associated with antisunward convecting polar ionospheric patches. The gradient drift instability (GDI) has been considered a primary candidate for the generation of these irregularities, or at least the long-wavelength energy source of the irregularity-wave cascade process. The Utah State University time-dependent ionospheric model (TDIM) enables the polar cap ionosphere and its patches to be modeled on a large scale in a time-evolving manner. Hence, at each point in space and time, the TDIM …

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Rayleigh Lidar Measurements Of The Temporal Frequency And Vertical Wavenumber Spectra In The Mesosphere Over The Rocky Mountain Region, X Gao, J W. Meriwether, Vincent B. Wickwar, T D. Wilkerson, S C. Collins Jan 1998

Rayleigh Lidar Measurements Of The Temporal Frequency And Vertical Wavenumber Spectra In The Mesosphere Over The Rocky Mountain Region, X Gao, J W. Meriwether, Vincent B. Wickwar, T D. Wilkerson, S C. Collins

All Physics Faculty Publications

Temporal and spatial spectral analysis techniques were applied to lidar data collected over a period of 18 months above the Rocky Mountain region at an altitude range from 45 to 70 km by a Rayleigh lidar system located in Logan, Utah (41.7°N, 111.8°W). Examination of the averaged temporal frequency F(ω) and vertical wavenumber F(m) spectra showed spectral slope values of −1.49 ± 0.03 and −2.3 ± 0.1, respectively. The observed slope for the overall averaged F(m) spectrum is considerably more positive than the value of −3 predicted by the linear instability theory but close to the …

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Ionospheric Storm Simulations Driven By Magnetospheric Mhd And Empirical Models With Data Comparisons, Jan Josef Sojka, Robert W. Schunk, M. D. Bowline, J. Chen, S. Slinker, J. Fedder, P. J. Sultan Jan 1998

Ionospheric Storm Simulations Driven By Magnetospheric Mhd And Empirical Models With Data Comparisons, Jan Josef Sojka, Robert W. Schunk, M. D. Bowline, J. Chen, S. Slinker, J. Fedder, P. J. Sultan

All Physics Faculty Publications

The results of two ionospheric simulations are compared with each other and with ionospheric observations of the southern hemisphere for the magnetic cloud passage event of January 14, 1988. For most of the event one simulation agrees with observations, while the other does not. Electric fields and electron precipitation patterns generated by a magnetospheric MHD model are used as inputs to a physical model of the ionosphere in the successful simulation, while empirical electric fields and electron precipitation are used as the inputs for the second simulation. In spite of ionospheric summer conditions a large and deep polar hole is …

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Effects Of The Evolution Of Spacecraft Surfaces On Secondary Electron Emission Andspacecraft Charging, R. E. Davies, John R. Dennison Jan 1998

Effects Of The Evolution Of Spacecraft Surfaces On Secondary Electron Emission Andspacecraft Charging, R. E. Davies, John R. Dennison

All Physics Faculty Publications

Spacecraft charging due to the natural plasma environment found in all orbits is known to produce many of the observed spacecraft anomalies and failures. A primary factor in adverse spacecraft charging is the secondary electron emission of differing materials on the spacecraft. Precipitating electrons and ions from the plasma to spacecraft surfaces can result in varying amounts of charge being released, depending on the secondary electron yield of the materials; this can lead to arcing between surfaces. NASA's Space and Environments Effects (SEE) program has recognized the need to improve their current materials database for modeling spacecraft charging and have …

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New Conformal Gauging And The Electromagnetic Theory Of Weyl, James Thomas Wheeler Jan 1998

New Conformal Gauging And The Electromagnetic Theory Of Weyl, James Thomas Wheeler

All Physics Faculty Publications

A new eight-dimensional conformal gauging solves the auxiliary field problem and eliminates unphysical size change from Weyl’s electromagnetic theory. We derive the Maurer–Cartan structure equations and find the zero curvature solutions for the conformal connection. By showing that every one-particle Hamiltonian generates the structure equations we establish a correspondence between phase space and the eight-dimensional base space, and between the action and the integral of the Weyl vector. Applying the correspondence to generic flat solutions yields the Lorentz force law, the form and gauge dependence of the electromagnetic vector potential and minimal coupling. The dynamics found for these flat solutions …

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Quantum Fields At Any Time, Charles G. Torre, Madhavan Varadarajan Jan 1998

Quantum Fields At Any Time, Charles G. Torre, Madhavan Varadarajan

All Physics Faculty Publications

The canonical quantum theory of a free field using arbitrary foliations of a flat two-dimensional spacetime is investigated. It is shown that dynamical evolution along arbitrary spacelike foliations is unitarily implemented on the same Fock space as that associated with inertial foliations. It follows that the Schrodinger picture exists for arbitrary foliations as a unitary image of the Heisenberg picture for the theory. An explicit construction of the Schrodinger picture image of the Heisenberg Fock space states is provided. The results presented here can be interpreted in terms of a Dirac constraint quantization of parametrized field theory. In particular, it …

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Magnetic Control Of Convection In Nonconducting Paramagnetic Fluids, J. Huang, Boyd F. Edwards, D. D. Gray Jan 1998

Magnetic Control Of Convection In Nonconducting Paramagnetic Fluids, J. Huang, Boyd F. Edwards, D. D. Gray

All Physics Faculty Publications

An inhomogeneous magnetic field exerts a magnetic body force on magnetically permeable fluids. A recent experiment [D. Braithwaite, E. Beaugnon, and R. Tournier, Nature (London) 354, 134 (1991)] demonstrates that this force can be used to compensate for gravity and to control convection in a paramagnetic solution of gadolinium nitrate. We provide the theory of magnetically controlled convection in a horizontal paramagnetic fluid layer heated from either above or below. Our theoretical predictions agree with the experiments.

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Evolution Of Secondary Electron Emission Characteristics Of Spacecraft Surfaces: Importance To Spacecraft Charging, R. E. Davies, John R. Dennison Jan 1998

Evolution Of Secondary Electron Emission Characteristics Of Spacecraft Surfaces: Importance To Spacecraft Charging, R. E. Davies, John R. Dennison

All Physics Faculty Publications

Secondary electron emission (SEE) plays a key role in spacecraft charging [Garrett, 1981; Frooninckx and Sojka, 1992] . As a result, spacecraft charging codes require knowledge of the SEE characteristics of various materials in order to predict vehicle potentials in various orbital environments [Katz, et. al., 1986]. Because SEE is a surface phenomenon, occurring in the first few atomic layers of a material, the SEE characteristics of a given surface are extremely sensitive to changes in surface condition—e.g., the addition or removal of surface contaminants, or changes in surface morphology. That spacecraft surfaces can and generally do undergo significant evolution …

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Physisorbed Co On Ionic Crystals: An Extended Beg Spin-Lattice Model Of Adsorbed Dipolar Molecules, T. E. Burns, Jr Dennison Jan 1998

Physisorbed Co On Ionic Crystals: An Extended Beg Spin-Lattice Model Of Adsorbed Dipolar Molecules, T. E. Burns, Jr Dennison

Journal Articles

The 2D dielectric phases and phase transitions of adsorbed dipolar molecules are studied using a dilute spin-one Ising model. The spin-one formulation assigns a spin Si = ±1 to a (up/down) dipole occupying a lattice site i adsorbed perpendicular to the substrate surface and Si = 0 to unoccupied sites. We relate the mean field expression for the spin-model interaction energy to a more detailed microscopic model involving dipolar, quadrupolar and dispersive interactions beyond nearest neighbor. Analytic solutions in the mean field approximation are discussed for dipole-orientation order-disorder transitions and ferroelectric-to-antiferroelectric transitions as a function of temperature and …

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North Round Valley Timber Sale Final Environmental Impact Statement, United States Forest Service Jan 1998

North Round Valley Timber Sale Final Environmental Impact Statement, United States Forest Service

Final Environmental Impact Statements (ID)

This Final Environmental Impact Statement (FEIS) documents three management alternatives analyzed for the North Round Valley Timber Sale. This sale is to be offered in 1998 and administered by the New Meadows Ranger District of the Payette National Forest. The North Round Valley sale planning area is located on the New Meadows Ranger District, 10 to 15 miles northwest of New Meadows.

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Challis Resource Area Proposed Resource Management Plan And Final Environmental Impact Statement Volume 2 (Of 2), United States Department Of The Interior, Bureau Of Land Management Jan 1998

Challis Resource Area Proposed Resource Management Plan And Final Environmental Impact Statement Volume 2 (Of 2), United States Department Of The Interior, Bureau Of Land Management

Resource Management Plans (ID)

The climate of the Challis Resource Area is influenced primarily by maritime air carried eastward on prevailing westerly winds. General climatic characteristics are abundant sunshine, low humidity, and high evaporation. The major precipitation source, particularly for winter storms, is the Northern Pacific Ocean. In the summer, however, most of the thunderstorm activity is caused by moisture-laden air originating from the south, off the Pacific coast of Mexico.

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Challis Resource Area Proposed Resource Management Plan And Final Environmental Impact Statement, United States Department Of The Interior, Bureau Of Land Management Jan 1998

Challis Resource Area Proposed Resource Management Plan And Final Environmental Impact Statement, United States Department Of The Interior, Bureau Of Land Management

Resource Management Plans (ID)

The Challis Proposed Resource Management Plan/Final Environmental Impact Statement (PRMP/FEIS) describes the Bureau of Land Management's proposed plan for managing approximately 792,567 acres of public lands administered by the BLM within the Challis Resource Area. The PRMP/FEIS is based on the Preferred Alternative (Alternative 2) described in the Challis Draft RMP/EIS (BLM, May 1996), as modified in response to public and tribal comments and internal BLM recommendations. It describes changes from and corrections to the Challis Draft RMP/EIS, updates the discussion of the affected environment, provides an analysis of environmental consequences for the Proposed RMP, and records public comments and …

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Razorback Sucker (Xyrauchen Texanus) Recovery Plan, Harold M. Tyus Jan 1998

Razorback Sucker (Xyrauchen Texanus) Recovery Plan, Harold M. Tyus

All U.S. Government Documents (Utah Regional Depository)

The Colorado River of the American West supports a mainstream fish community that is classified as the “Big River” fishes. Four of these fishes are listed as endangered under provisions of the Endangered Species Act of 1973, as amended. Three fishes (i.e., Colorado pike minnow Ptychocheilus Lucius, humpback chub Gila cypha, and bonytail G. elegans) have been listed for over 10 years, and they have recovery plans that were prepared prior to designation of critical habitats. Recently the Colorado squawfish was renamed by the American Fisheries Society and hereafter will be refered to in this document as the Colorado pike …

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Bighorn National Forest Draft Noxious Weed Management Environmental Assessment, United States Forest Service Jan 1998

Bighorn National Forest Draft Noxious Weed Management Environmental Assessment, United States Forest Service

All U.S. Government Documents (Utah Regional Depository)

The Forest Service proposes to implement a management plan to control noxious weeds on the Bighorn National Forest. This management plan would be in accordance with general direction in the Land and Resource Management Plan (LRMP) to treat noxious farm weeds (Bighorn National Forest LRMP, III-45) to improve range conditions and manage undersirable plant species. Five additional Federal Laws also address this action: 1. The Forest and Rangeland Renewable Resources Planning Act of 1974 (RPA, P.L. 93-378). 2. The Public Rangeland Improvement Act of 1978. 3. The Federal Noxious Weed Act of 1974 Section 2(b)(2) and Section 2 of (P.L. …

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Rawlins Rmp Biological Assessment, Bureau Of Land Management Jan 1998

Rawlins Rmp Biological Assessment, Bureau Of Land Management

All U.S. Government Documents (Utah Regional Depository)

This Biological Assessment (BA) is prepared for the Draft Environmental Impact Statement (DEIS) that describes the comprehensive analysis of alternatives for the planning and management of public lands and resources administered by the Bureau of Land Management (BLM) in the Rawlins area of Wyoming. The public lands and federal mineral estate within the RFO Resource Management Planning Area (RMPPA) are the subject of the planning effort (DEIS) and this document. This document is a component of the BLM Draft Environmental Impact Statement Resource Management Plan (RMP) and is prepared in compliance with the National Environmental Policy Act (NEPA) which requires …

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Clow Point Winter Recreation Parking Area Environmental Assessment, United States Forest Service Jan 1998

Clow Point Winter Recreation Parking Area Environmental Assessment, United States Forest Service

All U.S. Government Documents (Utah Regional Depository)

Payette National Forest proposes to authorize the construction, maintenance, and operation of a two-acre winter recreation parking site just below the Goose Creek overlook (Clow Point) along the Goose Lake Road (FDR #257).

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Environmental Assessment Caribou Timber Sale, United States Forest Service Jan 1998

Environmental Assessment Caribou Timber Sale, United States Forest Service

All U.S. Government Documents (Utah Regional Depository)

One of the decisions made in the 1985 Bighorn National Forest Land and Resource Management Plan (Forest Plan) was that timber sale offerings would be made. The Caribou timber sale was proposed in order to implement that Forest Plan allocation decision. The selection of this sale area was based upon several factors, including: Past forest management decisions and silvicultural prescriptions; the existence of a road system, which will minimize impacts upon wildlife habitat and water quality; the opportunity to change the forested vegetation to improve, or at least maintain within the Forest Plan standard and guidelines and other legal requirements, …

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Ruby Canyon/Black Ridge Integrated Resource Management Plan, Record Of Decision And Finding Of No Significant Impact, United States Bureau Of Land Management Jan 1998

Ruby Canyon/Black Ridge Integrated Resource Management Plan, Record Of Decision And Finding Of No Significant Impact, United States Bureau Of Land Management

All U.S. Government Documents (Utah Regional Depository)

The decision to implement this plan is in conformance with the 1987 Grand Junction Resource Area Resource Management Plan (RMP). Many of the management actions being proposed in the plan constitute an amendment of the RMP. This integrated resource management plan employs a "benefits based management approach" which expands our management focus beyond lands and resources to also address resulting outcomes as improved conditions. Plan implementation for the RCBR ecosystem will be done through an interdisciplinary ad-hoc committee which defines issues and prioritizes management actions. In addition, the vision statement developed by the ad-hoc committee will continue to provide guidance …

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A Framework For Understanding Social Science Contributions To Ecosystem Management, Joanna Endter-Wada, Dale Blahna, Richard Krannich, Mark W. Brunson Jan 1998

A Framework For Understanding Social Science Contributions To Ecosystem Management, Joanna Endter-Wada, Dale Blahna, Richard Krannich, Mark W. Brunson

Environment and Society Faculty Publications

We propose a framework for understanding the role that the social sciences should play in ecosystem management. Most of the ecosystem management literature assumes that scientific understanding of ecosystems is solely the purview of natural scientists. While the evolving principles of ecosystem management recognize that people play an important role, social considerations are usually limited to political and decision-making processes and to development of environmental education. This view is incomplete. The social science aspect of ecosystem management has two distinct components: one that concerns greater public involvement in the ecosystem management decision-making process, and one that concerns integrating social considerations …

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Cloud Peak Wilderness Management Direction Final Environmental Assessment For The Amendment To The Bighorn National Forest Land And Resource Management Plan, United States Forest Service Jan 1998

Cloud Peak Wilderness Management Direction Final Environmental Assessment For The Amendment To The Bighorn National Forest Land And Resource Management Plan, United States Forest Service

Environmental Assessments (WY)

The purpose of this EA is to amend the Land and Resource Management Plan (LRMP) for the Wilderness Management Standards and Guidelines (S&Gs). The need for the revised S&Gs is to provide more definable and measurable standards related to the items described in the Proposed Action. Current S&Gs do not provide sufficient direction to determine the trend of the Cloud Peak Wilderness (CPW) condition or require conflicting actions. The proposed S&Gs will facilitate determination of the trend of physical, biological and social aspects of the wilderness resource.

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Record Of Decision For The Greybull Valley Dam And Reservoir Environmental Impact Statement, United States Department Of The Interior, Bureau Of Land Management Jan 1998

Record Of Decision For The Greybull Valley Dam And Reservoir Environmental Impact Statement, United States Department Of The Interior, Bureau Of Land Management

Record of Decisions (WY)

This document records the decision made by the Wyoming State Director of the Bureau of Land Management (BLM) to grant a right-of-way under the authority of Section 5 of the Federal Land Policy and Management Act of 1976 (FLPMA), across BLM-administered lands (public lands) to the Greybull Valley Irrigation District, for the construction of a dam and reservoir project, as described in the Greybull Valley Dam and Reservoir Draft and Final Environmental Impact Statements.

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Final Environmental Impact Statement For The Powder River Coal Lease Application (Wyw136142) And Thundercloud Coal Lease Application (Wyw136458), United States Department Of The Interior, Bureau Of Land Management Jan 1998

Final Environmental Impact Statement For The Powder River Coal Lease Application (Wyw136142) And Thundercloud Coal Lease Application (Wyw136458), United States Department Of The Interior, Bureau Of Land Management

Final Environmental Impact Statements (WY)

This Final Environment Impact Statement (FEIS) assesses the environmental consequences of a federal decision to offer two federal coal tracts in southeastern Campbell County, Wyoming for lease at separate, competitive, sealed bid sales, subject to standard and special lease stipulations. The Powder River Lease By Application (LBA) Tract as applied for by Powder River Coal Company includes approximately 4,020 acres containing approximately 515 million tons of federal coal. Powder River coal company operates the adjacent North Antelope and Rochelle Mines. The Thundercloud LBA Tract, which is located approximately 9 miles north of the Powder River LBA Tract, was applied for …

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Record Of Decision And Finding Of No Significant Impact For The Shirley Mountain Planning Review Travel Management, United States Department Of The Interior, Bureau Of Land Management Jan 1998

Record Of Decision And Finding Of No Significant Impact For The Shirley Mountain Planning Review Travel Management, United States Department Of The Interior, Bureau Of Land Management

Record of Decisions (WY)

The planning review was conducted to analyze and weigh the affects of retaining or changing the Off-Road Vehicle (ORV) designation for the BLM-administered public lands within the Shirley Mountain Planning Review Area. The proposed decision considers comments received during public scoping and the 45-day comment period for the Shirley Mountain Planning Review Travel Management Environmental Assessment (EA).

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Decision Record For The Environmental Assessment For Coal Planning Decisions In The Carbon Basin Area Of The Great Divide Resource Area, United States Department Of The Interior, Bureau Of Land Management Jan 1998

Decision Record For The Environmental Assessment For Coal Planning Decisions In The Carbon Basin Area Of The Great Divide Resource Area, United States Department Of The Interior, Bureau Of Land Management

Record of Decisions (WY)

The Federal Coal Leasing Amendments Act of 1976 requires that Federal coal lands to be considered for leasing must be identified in a comprehensive land use plan. At the time the Great Divide Resource Management Plan (GDRA RMP, 1990) was prepared, approximately 60% of the Federal coal lands in the Carbon Basin Coal Area were leased and exempt from the coal screening/planning process. Subsequently, development of this lease was never pursued and the lease expired. In addition, the coal screening/planning process was not conducted on the remainder of the Federal coal lands in the Carbon Basin area during the RMP …

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Record Of Decision Jonah Field Ii Natural Gas Development Project Environmental Impact Statement, United States Department Of The Interior, Bureau Of Land Management Jan 1998

Record Of Decision Jonah Field Ii Natural Gas Development Project Environmental Impact Statement, United States Department Of The Interior, Bureau Of Land Management

Record of Decisions (WY)

This document records the decision made by the Bureau of Land Management (BLM) for managing the public land surface and federal mineral estate in the Jonah II Area Natural Gas Development project (hereafter referred to as the Jonah II Project). The Jonah II Project area comprises approximately 59,600 acres of Federal, State, and private land ownership. Of this total, approximately 56,400 acres are BLM administered or 95 percent; 2,560 acres are State of Wyoming or 4 percent; and 640 acres are private surface/federal minerals, or 1 percent. See Map 1.1 for the location of the Jonah II Project.

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Relativistic Electron In The Field Of Two Coulomb Centers, V.I. Matveev, D.U. Matrasulov, Kh. Yu. Rakhimov Jan 1998

Relativistic Electron In The Field Of Two Coulomb Centers, V.I. Matveev, D.U. Matrasulov, Kh. Yu. Rakhimov

Turkish Journal of Physics

Ground state wave function and the energy term of the relativistic electron moving in the field of two Coulomb centers are calculated analytically by the method of linear combination of atomic orbitals. Obtained analytical formula is applied to the calculation of the critical distance between two heavy nuclei at which energy term reaches the boundary of the lower continuum.

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On The One-Loop Yukowa Coupling Beta Function To Order Yg^2 In A General \Alpha Gauge And Its Gauge Indepence, M. Özer Jan 1998

On The One-Loop Yukowa Coupling Beta Function To Order Yg^2 In A General \Alpha Gauge And Its Gauge Indepence, M. Özer

Turkish Journal of Physics

We present the calculation of the one-loop Yukawa coupling beta function to order $Yg^2$ in a general $\alpha$ gauge, where $Y$ and $g$ are Yukawa and gauge couplings. We show explicitly how the gauge parameter $\alpha$ cancels out from the beta - function and demonstrate how some familiar results are obtained from it.

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The Milne And The Constant Source Problems For The Fbis Kernel, M.Ç .. Güleçyüz, A. Kaşkaş Jan 1998

The Milne And The Constant Source Problems For The Fbis Kernel, M.Ç .. Güleçyüz, A. Kaşkaş

Turkish Journal of Physics

Transport solutions to the monoenergetic constant source and the Milne problems for the forward-backward-isotropic scattering (FBIS) kernel are obtained by method of singular expansion modes. The monoenergetic linear transport equation for extremely anisotropic scattering with constant source is reduced to a transport equation with isotropic scattering. The expansion coefficient is obtained in a form involving exact integral equations and determined by the accompanying new boundary conditions and the half-range orthogonality relations. In the zeroth order approximation, the analytical expressions for neutron density and the emergent angular distributions are also obtained as a function of forward scattering.

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Topics On The Physics Potential And Detector Aspects Of The Lc-Hera Ep Collider, A. De Roeck Jan 1998

Topics On The Physics Potential And Detector Aspects Of The Lc-Hera Ep Collider, A. De Roeck

Turkish Journal of Physics

We present a brief account of some physics topics which could be addressed at a collider consisting of the HERA proton ring and the future $e^+e^-$ Linear Collider. A few experimental aspects are also discussed.

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Physics At Future Ep, \Gammap (Linac-Ring) And \Mup Colliders, Ilya F. Ginzburg Jan 1998

Physics At Future Ep, \Gammap (Linac-Ring) And \Mup Colliders, Ilya F. Ginzburg

Turkish Journal of Physics

The physical problems for the enumerated colliders are discussed. It is taken into account that all these machines can work only after corresponding parental colliders.

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