[en] Different models of single-mode laser were investigated in the situation of cross-correlation between the real and imaginary parts of the quantum noise. It was found that the amplitude equations of different models contain the same novel term. So the amplitude equations of all kinds of models could be written into a general form, which is called as the new amplitude equation. Further we use this new amplitude equation to research specifically the transient properties of white-gain model, the analytical results of the mean, variance, and skewness of first-passage-time (FPT) distributions for the white-gain model are presented, and compared with experimental measurements together with the other two theoretical results. We can conclude that: - because of the presence of the novel term containing the cross-correlation coefficient λ_q between the real and the imaginary parts of the quantum noise, the expression of mean, variance, and skewness of FPT will change according to different value of λ_q; - when λ_q=0.15, the agreement between the theoretical curve we obtained with experimental result is more better than the two others. So the new amplitude equation we derived can well describe the transient process of a single-mode laser

[en] We present an analytic investigation of the mean first passage time in two opposite directions (from the left well to the right well and from right to left) by studying symmetrical bistable systems driven by correlated Gaussian white noises, and prove that the mean first passage time in two opposite directions is not symmetrical any more when noises are correlated. As examples, the mean first passage time in the quartic bistable model and the sawtooth bistable model are calculated, respectively. From the analytic results of the mean first passage time, we testify further the relation T(from x_- to x₊,λ)≠T(from x₊ to x_-,λ) in the same area of the parameter plan. Moreover, it is found that the dependences of T⁺ (i.e., T(from x_- to x₊,λ)) and T^- (i.e., T(from x₊ to x_-,λ)) upon the multiplicative noise intensity Q and the additive noise intensity D exhibit entirely different properties. For same areas of the parameter plan: in the quartic bistable system, when the T⁺ vs. Q curve exhibits a maximum, while the T^- vs. Q curve is monotonous; when the T⁺ vs. D curve is monotonous, while the T^- vs. D curve experiences a phase transition from decreasing monotonously to possessing one minimum. Increasing Q, when the T⁺ vs. D curve experiences a phase transition from decreasing monotonously to possessing one maximum, while the T^- vs. D curve only increases monotonously. Similar behaviours also exist in the sawtooth bistable model

[en] The double-differential cross sections of outgoing neutrons and alpha particles of the ¹²C(n,xn) and ¹²C(n,χα) reactions are measured. A new nuclear reaction model for light nuclei is proposed to analyze the measured data. Because of a strong recoil effect in light nucleus reactions, the energy balance is strictly taken into account. Based on this new method, the LUNF code is developed to calculate all kinds of reaction cross sections and energy-angular distributions for the n + ¹²C reaction in the 4.8- to 20-MeV energy region. The reaction channel of (n,nprime3α) may proceed via a number of different reaction channels, as sequential particle emissions and two-body separation. The comparisons of the calculated results with the measured experimental data indicate that the model calculations are successful for outgoing neutrons. Also, kerma factors derived from the calculated results are compared with the measurements

[en] Substitution of rare earth atoms for Y in ultrathin films of the YBa₂Cu₃O_7-δ (YBCO) high temperature superconductor influences its superconducting properties, most notably the transition temperature T_c. One important reason for this is epitaxial strain in the films. The strain depends on the size of the RBCO unit cell and thus on the R (= Y or rare earth) ionic radius but also on the lattice constant of the chosen substrate. We report correlations between T_c and epitaxial strain for YBCO and GdBCO films on SrTiO₃(001) and NdGaO₃(001). (orig.)

[en] Full text of publication follows. The scientific mission of EAST is to explore the reactor relevant regimes with long pulse lengths and high plasma core confinement and to develop and verify solutions for power exhaust and particle control under steady state operation. One of the main research goals of EAST involves long steady-state high-performance plasma pulse. It is a fusion engineering challenge to handle steady-state high heat flux form plasma. To accomplish this aim, 3 generation divertors have been designed for EAST to withstand high heat flux whose peak values are increasing rapidly. The first generation divertors were used on the initial phase of the plasma burning as there was no any cooling for divertors. The first generation divertors are just stainless plate 5 mm in thickness bolted on supports which had been applied since 2006 to 2007. From 2008 to 2013 the longest EAST pulse has reached 400 s and the peak heat flux on divertor exceed 2 MW/m². The second generation divertors were used during this phase. The divertors consist of graphite tiles, heat sink and supports. The graphite tiles coated with SiC were mounted on heat sink. The heat sink has several cooling channels and cooling water was pumped in from pipes to remove thermal power. The third generation divertors are ITER-like W mono-block structure. They are going to be used in 2014. The newest design is expected to withstand the higher heat flux that is more than 10 MW/m². Material W is a hard melt metal with large strength. The cooling CuCrZr pipe connects with W mono-blocks directly. Simulation and test proved that such structure have higher reliability and more duty time than the past design. We are making every effort to improve thermal extraction technology of divertor by comparing and practice different designs. The process of divertor heat transfer has been studied to define key design variables and explored the relationship between design variable and heat transfer efficiency. All such efforts made in EAST can bring experiences and answers for ITER or any next divertor fusion device on nuclear phase. (author)

[en] In order to verify experimentally and compare recent ion theories for cylindrical electrostatic probes, the ion density in a radio-frequency plasma was evaluated from V-I curves by means of six different theories. At low pressures, the theories of Bernstein and Rabinowitz, of Lam and Laframboise, give values of density which differ respectively by 20, 25 and 30% compared with the values obtained using a 10GHz focussed microwave interferometer. At the continuum limit, The Schulz and Brown's, and Su and Kiel's theories give density values which disagree respectively by 55 and 20%, compared with the values obtained by microwaves. For pressures varying from 0.05 to 3mmHg, the decrease of ion current, as predicted theorically by Waymouth, was observed. The density perturbation near the probe was found to be a dominant factor affecting the precision of density measurements, for pressures up to 2mmHg at least for our experimental conditions

[en] The x-ray standing wave (XSW) technique is used to measure the isotopic mass dependence of the lattice constants of Si and Ge. Backreflection allows substrates of moderate crystallinity to be used while high order reflection yields high accuracy. The XSW, generated by the substrate, serves as a reference for the lattice planes of an epilayer of different isotopic composition. Employing XSW and photoemission, the position of the surface planes is determined from which the lattice constant difference Δa is calculated. Scaled to ΔM=1 amu we find (Δa/a) of -0.36 x 10^-5 and -0.88 x 10^-5 for Ge and -1.8 x 10^-5 and -3.0 x 10^-5 for Si at 300 and 30K, respectively

[en] We consider the α-geometric structure of the thermodynamic manifolds S which characterizes a given physical system. We obtain the α-Gaussian curvature which is the generalization of the Riemannian Gaussian curvature. We set up a submanifold M which is a 1-flat submanifold of S. By introducing the Kullback-Leibler divergence, we get the optimal estimation point on M from a point on S by means of projection, and the optimal estimation point on M from a point on S by means of projection, and the optimal estimation point is unique. At last, we give an example to illustrate our results.

[en] The authors propose to investigate the dynamics of plasmas in the warm dense matter (WDM) regime on ultra-short time scales. Accessible plasma conditions are in the density range of n = 10²⁰ - 10²³ cm^-3 and at moderate temperatures of T = 1 - 20 eV. These plasmas are of importance for laboratory astrophysics, high energy density science and inertial confinement fusion. They are characterized by a coupling parameter of Λ ∼> 1, where electromagnetic interactions are of the same order as the kinetic energy. The high density of the plasma makes it opaque to radiation in the visible range and, as a consequence, UV up to x-ray radiation can be used to probe such systems. Therefore a wide range in the temperature-density plane of WDM is presently unexplored and only the VUV-FEL opens for the first time the opportunity for its detailed investigation. In equilibrium, the macroscopic state of the plasma is completely characterized by its density and temperature. In pump-probe experiments however, the plasma is initially in a nonequilibrium state and relaxes towards equilibrium within the relaxation time τ_R. For t > τ_R, the plasma is in an equilibrium state and expands hydrodynamically on a time scale τ_H. The proposed experiment measures the time-resolved Thomson scattering signal with the VUV-FEL radiation characterizing the plasma in equilibrium and nonequilibrium states. Both regimes are extremely interesting and will provide new insight into the following phenomena: (1) details of nonequilibrium correlations, (2) relaxation phenomena, (3) hydrodynamic expansion, (4) recombination kinetics. The time-resolved Thomson scattering signal is obtained in a pump-probe experiment by varying the delay between pump and probe. The final stage of the relaxation process (t ∼ τ_R) is of special interest since the plasma components (electrons and ion species) can be assumed to be in quasi-equilibrium. This allows for accurate measurements of the electron temperature using the detailed balance relation. For times t ∼< τ_R the scattering spectrum provides also the plasmon damping in nonequilibrium from which information on the formation and decay of collective excitations at short time scales can be obtained. At large time scales (t ∼> τ_H) the hydrodynamic expansion of the plasma sets in. Detailed information on the evolution of the plasma in this regime is available from sophisticated hydrodynamic computer simulations which can be tested with the proposed measurements. With the decreasing plasma density due to the expansion, recombination processes become important and need to be considered as well

[en] A CANDU-SCWR core is designed by using a 3D neutronics/thermal-hydraulic coupling method. In the fuel channel design, a typical 43-element fuel bundle is used, the coolant is supercritical light water, and the moderator is heavy water, the thickness of which is optimized to ensure the negative coolant coefficient during operation. The core has a power of 1220 MWe with a diameter of 4.8m and length of 4.95m, and there are totally 300 fuel channels, each of which consists of 10 fuel bundles. The coolant inlet temperature is set to be 350 ℃ and the operation pressure is 25 MPa. In order to flatten the radial power distribution, the loading pattern of the equilibrium cycle is optimized, and an improved in-out fuel management scheme is used with three batches refueling, burnable poison Dy₂O₃ is used to flatten the power peaking. The numerical results show that the average power density is 42.75 W/cm³, while the maximum linear element rate(LER) is 575W/cm. The average discharged burnup of the equilibrium is 48.3GWD/tU, and a high average coolant outlet temperature of 625 ℃ is achieved with a maximum cladding surface temperature less than 850 ℃. Besides, the coolant temperature coefficient is negative throughout the cycle. (author)