Universality class of the restricted solid-on-solid model with hopping

We study the restricted solid-on-solid (RSOS) model with finite hopping distance $l_{0}$, using both analytical and numerical methods. Analytically, we use the hard-core bosonic field theory developed by the authors [Phys. Rev. E {\bf 62}, 7642 (2000)] and derive the Villain-Lai-Das Sarma (VLD) equation for the $l_{0}=\infty$ case which corresponds to the conserved RSOS (CRSOS) model and the Kardar-Parisi-Zhang (KPZ) equation for all finite values of $l_{0}$. Consequently, we find that the CRSOS model belongs to the VLD universality class and the RSOS models with any finite hopping distance belong to the KPZ universality class. There is no phase transition at a certain finite hopping distance contrary to the previous result. We confirm the analytic results using the Monte Carlo simulations for several values of the finite hopping distance.Comment: 13 pages, 3 figure

Low-dimensional dynamics embedded in a plane Poiseuille flow turbulence : Traveling-wave solution is a saddle point ?

The instability of a streak and its nonlinear evolution are investigated by direct numerical simulation (DNS) for plane Poiseuille flow at Re=3000. It is suggested that there exists a traveling-wave solution (TWS). The TWS is localized around one of the two walls and notably resemble to the coherent structures observed in experiments and DNS so far. The phase space structure around this TWS is similar to a saddle point. Since the stable manifold of this TWS is extended close to the quasi two dimensional (Q2D) energy axis, the approaching process toward the TWS along the stable manifold is approximately described as the instability of the streak (Q2D flow) and the succeeding nonlinear evolution. Bursting corresponds to the escape from the TWS along the unstable manifold. These manifolds constitute part of basin boundary of the turbulent state.Comment: 5 pages, 6 figure

Heisenberg-picture approach to the exact quantum motion of a time-dependent forced harmonic oscillator

In the Heisenberg picture, the generalized invariant and exact quantum motions are found for a time-dependent forced harmonic oscillator. We find the eigenstate and the coherent state of the invariant and show that the dispersions of these quantum states do not depend on the external force. Our formalism is applied to several interesting cases.Comment: 15 pages, two eps files, to appear in Phys. Rev. A 53 (6) (1996

Giant Magnetoelectric Effect in a Multiferroic Material with a High Ferroelectric Transition Temperature

We present a unique example of giant magnetoelectric effect in a conventional multiferroic HoMnO3, where polarization is very large (~56 mC/m2) and the ferroelectric transition temperature is higher than the magnetic ordering temperature by an order. We attribute the uniqueness of the giant magnetoelectric effect to the ferroelectricity induced entirely by the off-center displacement of rare earth ions with large magnetic moments. This finding suggests a new avenue to design multiferroics with large polarization and higher ferroelectric transition temperature as well as large magnetoelectric effects

Monovacancy-induced magnetism in graphene bilayers

Vacancy-induced magnetism in graphene bilayers is investigated using spin-polarized density functional theory calculations. One of two graphene layers has a monovacancy. Two atomic configurations for bilayers are considered with respect to the position of the monovacancy. We find that spin magnetic moments localized at the vacancy site decreases by ~10 % for our two configurations, compared with the graphene monolayer with a monovacancy. The reduction of the spin magnetic moment in the graphene bilayers is attributed to the interlayer charge transfer from the adjacent layer to the layer with the monovacancy, compensating for spin magnetic moments originating from quasilocalized defect state.Comment: 14 pages, 1 table and 4 figure

Derivation of continuum stochastic equations for discrete growth models

We present a formalism to derive the stochastic differential equations (SDEs) for several solid-on-solid growth models. Our formalism begins with a mapping of the microscopic dynamics of growth models onto the particle systems with reactions and diffusion. We then write the master equations for these corresponding particle systems and find the SDEs for the particle densities. Finally, by connecting the particle densities with the growth heights, we derive the SDEs for the height variables. Applying this formalism to discrete growth models, we find the Edwards-Wilkinson equation for the symmetric body-centered solid-on-solid (BCSOS) model, the Kardar-Parisi-Zhang equation for the asymmetric BCSOS model and the generalized restricted solid-on-solid (RSOS) model, and the Villain--Lai--Das Sarma equation for the conserved RSOS model. In addition to the consistent forms of equations for growth models, we also obtain the coefficients associated with the SDEs.Comment: 5 pages, no figur

Effect of Cutting Height on Productivity and Quality of Alfalfa in Northern Area of Korea

Alfalfa is a very important forage for livestock feeding. In particular, due to the high crude protein content, it is widely used as a dairy cattle feeds. However, the cultivation of alfalfa is quite limited and main source is imported hay in Korea. There are many reasons, but most importantly, low productivity due to lack of boron in the soil. This experiment was conducted to expand domestic production and use of alfalfa. Alfalfa was sown in the fall of 2018 at 30 kg/ha seeding rate. Alfalfa was harvested four times (3 May, 2 July, 11 September and 13 October) in 2019 with three different cutting height (5, 15 and 25 cm of stubble height) and investigate productivity, quality and regrowth. The plant height was the highest at the 3rd harvest (108 cm) and the dry matter content was the highest at the 1st harvest (28.78 %). The yield of fresh and dry matter was the highest at the first. Annual fresh and DM productivity was significantly higher in 5cm cutting height. CP was highest at the 4th harvest and lowest at the 3rd. The higher the cutting height, the higher CP content. ADF and NDF contents decreased significantly with increasing cutting height (p\u3c 0.05). TDN content was highest at the 4th harvest and lowest at the 3rd harvest. It was also found that the higher the cutting height, the higher the TDN content. The relative feed value (RFV) of alfalfa was highest at the 4th fourth harvest (mean 164) and lowest at the 3rd harvest (mean 85). The RFV value increased with increasing cutting height and 25 cm cutting height plot was 152. Regrowth after cutting was good at 15cm and 25cm height and 5cm treatment was slightly lower. In conclusion, the possibility of alfalfa production in Korea is sufficient and a cutting height of 5 cm or more is recommended and requires constant observation

Effect of Seeding Rates on Productivity and Quality of Alfalfa in Northern Area of Korea

Alfalfa cultivation in South Korea is not common. There are many reasons, but low productivity has been extremely limited. Although alfalfa growth was poor due to boron deficiency in the soil, the problem has recently been solved. Nevertheless, the cultivation of alfalfa is not expanding. About 200,000 tonnes of alfalfa hay are imported every year. Therefore, this study was conducted to find a way to replace imported hay by expanding alfalfa cultivation in Korea. Alfalfa (P5444) was sown in northern part of South Korea (Pyeongchang). Alfalfa was sown in September 2018 with different seeding rates (20, 30 and 40 kg/ha) and harvested four times in 2019 (3 May, 2 July, 11 September and 13 October). The plant height was the highest at the 3rd harvest (113 cm) and the dry matter content was the highest at the 1st harvest (27.89 %). The yield of fresh and dry matter was the highest at the first harvest (mean 6,856 kg/ha). Annual fresh and DM productivity was significantly higher in 40 kg/ha seeding rates (89,833 and 20,265 kg/ha). Crude protein (CP) content in forage quality was higher than 27% at the 4th harvest and the lowest by 13% at the 3rd harvest. Crude protein, ADF and NDF contents did not show significant difference (P\u3e 0.05) according to the increase of seeding rate. TDN content of alfalfa was not significantly different among treatments (P \u3e 0.05), but was highest at the 4th harvest (66.98 %) and lowest at the 3rd harvest (44.44 %). The relative feed value (RFV) of alfalfa was highest at the 4th fourth harvest (mean 146) and lowest at the 3rd harvest (mean 83). However, there was no significant difference among the seeding rates (average 120). In conclusion, the possibility of alfalfa production in Korea is sufficient and 40 kg/ha seeding rate is recommended

Infrared Excess and Molecular Gas in the Galactic Worm GW46.4+5.5

We have carried out high-resolution (~3') HI and CO line observations along one-dimensional cuts through the Galactic worm GW46.4+5.5. By comparing the HI data with IRAS data, we have derived the distributions of I_100 excess and tau_100 excess, which are respectively the 100 mum intensity and 100 mum optical depth in excess of what would be expected from HI emission. In two observed regions, we were able to make a detailed comparison of the infrared excess and the CO emission. We have found that tau_100 excess has a very good correlation with the integrated intensity of CO emission, W_CO, but I_100 excess does not. There are two reasons for the poor correlation between I_100 excess and W_CO: firstly, there are regions with enhanced infrared emissivity without CO, and secondly, dust grains associated with molecular gas have a low infrared emissivity. In one region, these two factors completely hide the presence of molecular gas in the infrared. In the second region, we could identify the area with molecular gas, but I_100 excess significantly underestimates the column density of molecular hydrogen because of the second factor mentioned above. We therefore conclude that tau_100 excess, rather than I_100 excess, is an accurate indicator of molecular content along the line of sight. We derive tau_100/N(H)=(1.00+-0.02)*10^-5~(10^20 cm^-2)^-1, and X=N(H_2)/W_CO=~0.7*10^20 cm^-2 (K km s^-1)^-1. Our results suggest that I_100 excess could still be used to estimate the molecular content if the result is multiplied by a correction factor xi_c=_HI/_H_2 (~2 in the second region), which accounts for the different infrared emissivities of atomic and molecular gas. We also discuss some limitations of this work.Comment: 10 pages, 9 postscript figures, uses aas2pp4.sty to be published in Astrophyslcal Journa