Temperature dependent subgroup formulation with number density adjustment for direct whole core power reactor calculation

2016 ◽  
Vol 96 ◽  
pp. 249-263 ◽  
Author(s):  
Yeon Sang Jung ◽  
Chang Hyun Lim ◽  
Han Gyu Joo
Keyword(s):  
Power Reactor ◽  
Number Density ◽  
Temperature Dependent ◽  
Reactor Calculation

LOWERING OF BOSON-FERMION SYSTEM ENERGY WITH A GAPPED COOPER RESONANT-PAIR DISPERSION RELATION

2007 ◽  
Vol 21 (13n14) ◽  
pp. 2335-2347 ◽  
Author(s):  
T. A. MAMEDOV ◽  
M. DE LLANO
Keyword(s):  
Pair Formation ◽  
Positive Energy ◽  
Total System ◽  
Fermion System ◽  
Number Density ◽  
Temperature Dependent ◽  
Continuous Processes ◽  
Free Fermions ◽  
Composite Bosons ◽  
System Energy

Applying two-time Green-function techniques to the Friedberg-T.D. Lee phenomenological Hamiltonian of a many-fermion system, it is shown that positive-energy resonant bosonic pairs associated with four-fermion excitations above the Fermi sea are energetically lower in a ground-state that is a mixture of two coexisting and dynamically interacting many-particle subsystems: a) unpaired fermions and b) composite bosons. It is argued that an interaction between free fermions and bosons excited above the Fermi sea in the mixture, namely, the continuous processes of pair-formation from, and disintegration into, two unpaired electrons, results in a substantially lowering the total system energy. The positive-energy composite bosons begin to appear incoherently below a depairing temperature T* as their coupling- and temperature-dependent number density gradually increases from zero. This leads quite naturally to the pseudogap phenomenon observed in high-Tc cuprates.

Mass Determination by Direct Measurement of Electron Scattering

1975 ◽  
Vol 33 ◽  
pp. 240-241
Author(s):  
M. K. Lamvik ◽  
A. V. Crewe
Keyword(s):  
Cross Section ◽  
Electron Scattering ◽  
Mass Density ◽  
Variable Mass ◽  
Scattering Cross Section ◽  
Mass Determination ◽  
Number Density ◽  
Cross Sectional ◽  
Thin Slice ◽  
Scattering Cross

If a molecule or atom of material has molecular weight A, the number density of such units is given by n=Nρ/A, where N is Avogadro's number and ρ is the mass density of the material. The amount of scattering from each unit can be written by assigning an imaginary cross-sectional area σ to each unit. If the current I0 is incident on a thin slice of material of thickness z and the current I remains unscattered, then the scattering cross-section σ is defined by I=IOnσz. For a specimen that is not thin, the definition must be applied to each imaginary thin slice and the result I/I0 =exp(-nσz) is obtained by integrating over the whole thickness. It is useful to separate the variable mass-thickness w=ρz from the other factors to yield I/I0 =exp(-sw), where s=Nσ/A is the scattering cross-section per unit mass.

(111) Monocrystalline Nickel Films

1972 ◽  
Vol 30 ◽  
pp. 512-513
Author(s):  
T.E. Pratt ◽  
R.W. Vook
Keyword(s):  
Film Thickness ◽  
Deposition Rate ◽  
Room Temperature ◽  
Narrow Range ◽  
High Vacuum ◽  
Residual Pressure ◽  
Temperature Dependent ◽  
Deposition Parameters ◽  
Transmission Electron ◽  
Substrate Temperatures

(111) oriented thin monocrystalline Ni films have been prepared by vacuum evaporation and examined by transmission electron microscopy and electron diffraction. In high vacuum, at room temperature, a layer of NaCl was first evaporated onto a freshly air-cleaved muscovite substrate clamped to a copper block with attached heater and thermocouple. Then, at various substrate temperatures, with other parameters held within a narrow range, Ni was evaporated from a tungsten filament. It had been shown previously that similar procedures would yield monocrystalline films of CU, Ag, and Au.For the films examined with respect to temperature dependent effects, typical deposition parameters were: Ni film thickness, 500-800 A; Ni deposition rate, 10 A/sec.; residual pressure, 10-6 torr; NaCl film thickness, 250 A; and NaCl deposition rate, 10 A/sec. Some additional evaporations involved higher deposition rates and lower film thicknesses.Monocrystalline films were obtained with substrate temperatures above 500° C. Below 450° C, the films were polycrystalline with a strong (111) preferred orientation.

In Vitro Effects of Urokinase — Prevention by Different Inhibitors

1990 ◽  
Vol 64 (03) ◽  
pp. 402-406 ◽  
Author(s):  
M D Oethinger ◽  
E Seifried
Keyword(s):  
In Vitro Study ◽  
Thrombin Time ◽  
Plasma Samples ◽  
Temperature Dependent ◽  
Chloromethyl Ketone ◽  
Control Value ◽  
Dose Time ◽  
In Vitro Effects ◽  
Full Protection

SummaryThe present in vitro study investigated dose-, time- and temperature-dependent effects of two-chain urokinase plasminogen activato(u-PA, urokinase) on normal citrated plasma. When 10 μg/ml u-PA wereadded to pooled normal plasma and incubated for 30 min at an ambient temperature (25° C), α2-antiplas-min decreased to 8% of the control value. Incubation on ice yielded a decrease to 45% of control,whereas α2-antiplasmin was fully consumed at 37° C. Fibrinogen and plasminogen fell to 46% and 39%, respectively, after a 30 min incubation at 25° C. Thrombin time prolonged to 190% of control.Various inhibitors were studied with respect to their suitability and efficacy to prevent these in vitro effects. Aprotinin exhibited a good protective effect on fibrinogen at concentrations exceeding 500 KlU/ml plasma. Its use, however, was limited due to interferences with some haemostatic assays. We could demonstrate that L-Glutamyl-L-Glycyl-L-Arginyl chloromethyl ketone (GGACK) and a specific polyclonal anti-u-PA-antibody (anti-u-PA-IgG) effectively inhibited urokinase-induced plasmin generation without interfering with haemostatic assays. The anti-u-PA-antibody afforded full protection ofα2-antiplasmin at therapeutic levels of u-PA.It is concluded that u-PA in plasma samples from patients during thrombolytic therapy may induce in vitro effects which should be prevented by the use of a suitable inhibitor such as GGACK or specific anti-u-PA-antibody.

Interventional Thermal Injury of the Arterial Wall: Unfolding of von Willebrand Factor and Its Increased Binding to Collagen after 55° C Heating

1996 ◽  
Vol 75 (03) ◽  
pp. 515-519 ◽  
Author(s):  
Mark J Post ◽  
Anke N de Graaf-Bos ◽  
George Posthuma ◽  
Philip G de Groot ◽  
Jan J Sixma ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Conformational Changes ◽  
Arterial Wall ◽  
Platelet Adhesion ◽  
Type I ◽  
Temperature Dependent ◽  
Collagen Types ◽  
Electron Microscopic ◽  
Von Willebrand ◽  
Willebrand Factor

Summary Purpose. Thermal angioplasty alters the thrombogenicity of the arterial wall. In previous studies, platelet adhesion was found to increase after heating human subendothelium to 55° C and decrease after heating to 90° C. In the present electron microscopic study, the mechanism of this temperature-dependent platelet adhesion to the heated arterial wall is elucidated by investigating temperature-dependent conformational changes of von Willebrand factor (vWF) and collagen types I and III and the binding of vWF to heated collagen. Methods. Purified vWF and/or collagen was applied to electron microscopic grids and heated by floating on a salt-solution of 37° C, 55° C or 90° C for 15 s. After incubation with a polyclonal antibody against vWF and incubation with protein A/gold, the grids were examined by electron microscopy. Results. At 37° C, vWF was coiled. At 55° C, vWF unfolded, whereas heating at 90° C caused a reduction in antigenicity. Collagen fibers heated to 37° C were 60.3 ± 3.1 nm wide. Heating to 55° C resulted in the unwinding of the fibers, increasing the width to 87.5 ± 8.2 nm (p < 0.01). Heating to 90° C resulted in denatured fibers with an enlarged width of 85.1 ± 6.1 nm (p < 0.05). Heating of collagen to 55° C resulted in an increased vWF binding as compared to collagen heated to 37° C or to 90° C. Incubation of collagen with vWF, prior to heating, resulted in a vWF binding after heating to 55° C that was similar to the 37° C binding and a decreased binding after 90° C. Conclusions. After 55° C heating, the von Willebrand factor molecule unfolds and collagen types I and III exhibit an increased adhesiveness for von Willebrand factor. Heating to 90° C denatures von Willebrand factor and collagen. The conformation changes of von Willebrand factor and its altered binding to collagen type I and III may explain the increased and decreased platelet adhesion to subendothelium after 55° C and 90° C heating, respectively.

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