32,090 research outputs found

    Chiral geometry and rotational structure for 130^{130}Cs in the projected shell model

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    The projected shell model with configuration mixing for nuclear chirality is developed and applied to the observed rotational bands in the chiral nucleus 130^{130}Cs. For the chiral bands, the energy spectra and electromagnetic transition probabilities are well reproduced. The chiral geometry illustrated in the K plotK~plot and the azithumal plotazithumal~plot is confirmed to be stable against the configuration mixing. The other rotational bands are also described in the same framework

    Experimentally-determined external heat loss of automotive gas turbine engine

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    An external heat balance was conducted on a 150 HP two-shaft automotive gas turbine engine. The engine was enclosed in a calorimeter box and the temperature change of cooling air passing through the box was measured. Cooling airflow ranges of 1.6 to 2.1 lb-per-second and 0.8 to 1.1 lb-per-second were used. The engine housing heat loss increased as the cooling airflow through the calorimeter box was increased, as would be the case in a moving automobile. The heat balance between the total energy input and the sum of shaft power output and various losses compared within 30 percent at engine idle speeds and within 7 percent at full power

    Ground-based testing of the dynamics of flexible space structures using band mechanisms

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    A suspension system based on a band mechanism is studied to provide the free-free conditions for ground based validation testing of flexible space structures. The band mechanism consists of a noncircular disk with a convex profile, preloaded by torsional springs at its center of rotation so that static equilibrium of the test structure is maintained at any vertical location; the gravitational force will be directly counteracted during dynamic testing of the space structure. This noncircular disk within the suspension system can be configured to remain unchanged for test articles with the different weights as long as the torsional spring is replaced to maintain the originally designed frequency ratio of W/k sub s. Simulations of test articles which are modeled as lumped parameter as well as continuous parameter systems, are also presented

    Particles in classically forbidden area, neutron skin and halo, and pure neutron matter in Ca isotopes

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    The nucleon density distributions and the thickness of pure neutron matter in Ca isotopes were systematically studied using the Skyrme-Hartree-Fock model (SHF) from the β\beta-stability line to the neutron drip-line. The pure neutron matter, related with the neutron skin or halo, was shown to depend not only on the Fermi levels of the neutrons but also on the orbital angular momentum of the valence neutrons. New definitions for the thickness of pure neutron matter are proposed.Comment: 6 pages, 5 figure

    Challenge on the Astrophysical R-process Calculation with Nuclear Mass Models

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    Our understanding of the rapid neutron capture nucleosynthesis process in universe depends on the reliability of nuclear mass predictions. Initiated by the newly developed mass table in the relativistic mean field theory (RMF), in this paper the influence of mass models on the rr-process calculations is investigated assuming the same astrophysical conditions. The different model predictions on the so far unreachable nuclei lead to significant deviations in the calculated r-process abundances.Comment: 3 pages, 3 figure

    China's Overt Economic Rise and Latent Human Capital Investment: Achieving Milestones and Competing for the Top

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    We provide an overview of China's economic rise through time. Over the past decade, China has maintained 10% growth in GDP, albeit with a GDP per capita at the low level of a developing country. Its tremendous economic development has overlooked the growing social inequalities and rising resentments of the ‘cheap’ workers and those laid off. The main contributor to its ascension is international trade and investment in physical capital, often at the expense of the environment. The year 1978 was the landmark for the foundation of the Chinese modern higher education system. Since then the number of students enrolled in Chinese higher education institutions has increased dramatically; China is producing serious scholars and a tremendous amount of scholarly output; more and more Chinese students seek higher education abroad; and international students find a rising interest in receiving education in China.China, human capital, brain drain, higher education

    Finite density phase transition of QCD with Nf=4N_f=4 and Nf=2N_f=2 using canonical ensemble method

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    In a progress toward searching for the QCD critical point, we study the finite density phase transition of Nf=4N_f = 4 and 2 lattice QCD at finite temperature with the canonical ensemble approach. We develop a winding number expansion method to accurately project out the particle number from the fermion determinant which greatly extends the applicable range of baryon number sectors to make the study feasible. Our lattice simulation was carried out with the clover fermions and improved gauge action. For a given temperature, we calculate the baryon chemical potential from the canonical approach to look for the mixed phase as a signal for the first order phase transition. In the case of Nf=4N_f=4, we observe an "S-shape" structure in the chemical potential-density plane due to the surface tension of the mixed phase in a finite volume which is a signal for the first order phase transition. We use the Maxwell construction to determine the phase boundaries for three temperatures below TcT_c. The intersecting point of the two extrapolated boundaries turns out to be at the expected first order transition point at TcT_c with μ=0\mu = 0. This serves as a check for our method of identifying the critical point. We also studied the Nf=2N_f =2 case, but do not see a signal of the mixed phase for temperature as low as 0.83 TcT_c.Comment: 28 pages, 11 figures,references added, final versio
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