• Korean Journal of Crystallography
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• v.8 no.2
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• pp.127-131
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• 1997

The crystal structure of a bromine sorption complex of vacuum-dehydrated Ag+ and Ca2+ exchanged zeolite A(a=12,234(1) Å) has been determined by single-crystal X-ray diffraction methods in the cubic space group Pm3m. The crystal was prepared by flow method using exchange solution in which mole ratio of AgNo3 and Ca(NO3)2 was 1:150 with a total concentration of 0.05M. The crystal was dehydrated at 360℃ and 2 ×10-6 Torr for 2days, followed by exposure to 180 Torr of Br2 vapor for 20min. full-matrix least-squares refinements converged to the final error indices of R1=0.111 and R2=0.101 using 90 reflections for which I>3o(I). About 3.1 Ag+ ions and 4.45 Ca2+ ions lie on the two crystallographically nonequivalent three-fold axes associated with 6-ring oxygens. A total of six bromine molecules are sorbed per unit cell. Each bromine molecule approaches a framework oxide ions axially (Br-Br-O=171(2)', O-Br=3.25(6) Å; and Br-Br=2,61(8) Å by a charge-transfer interaction.

• Korean journal of applied entomology
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• v.35 no.2
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• pp.119-125
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• 1996

Temperature-dependent development study for overwintered eggs of Pseudococcus comstocki (Kuwana) wasconducted to develop a forecasting model for egg hatch date. Hatch times of overwintered eggs were comparedat five constant temperatures (10, 15, 20, 25, 27$^{\circ}$C) and different collection dates. A nonlinear, four-parameterdevelopmental model with high temperature inhibition accurately described (R2=0.9948) mean developmentalrates of all temperatures. Variation in developmental times was modeled(~~=0.972w9)it h a cumulative Weibullfunction. Least-squares linear regression (rate=O.O06358[Temp.]-0.07566)d escribed development in the linearregion (15-25$^{\circ}$C) of the development curve. The low development threshold temperature was estimated 11.9"Cand 154.14 degree-days were required for complete development. The linear degree-day model (thermal summation)and rate summation model (Wagner et al. 1985) were validated using field phenology data. In degreedaymodels, mean-minus-base method, sine wave method, and rectangle method were used in estimation of dailythermal units. Mean-minus-base method was 18 to 28d late, sine wave method was 11 to 14d late, rectanglemethod was 3 to 5d late, and rate summation model was 2 to 3d late in predicting 50% hatch of overwinteredeggs. hatch of overwintered eggs.

• Wind and Structures
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• v.30 no.4
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• pp.433-450
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• 2020

The strong turbulence characteristic of typhoon not only will significantly change flow field characteristics surrounding the large-scale wind turbine and aerodynamic force distribution on surface, but also may cause morphological evolution of coast dune and thereby form sand storms. A 5MW horizontal-axis wind turbine in a wind power plant of southeastern coastal areas in China was chosen to investigate the distribution law of additional loads caused by wind-sand coupling movement of coast dune at landing of strong typhoons. Firstly, a mesoscale Weather Research and Forecasting (WRF) mode was introduced in for high spatial resolution simulation of typhoon "Megi". Wind speed profile on the boundary layer of typhoon was gained through fitting based on nonlinear least squares and then it was integrated into the user-defined function (UDF) as an entry condition of small-scaled CFD numerical simulation. On this basis, a synchronous iterative modeling of wind field and sand particle combination was carried out by using a continuous phase and discrete phase. Influencing laws of typhoon and normal wind on moving characteristics of sand particles, equivalent pressure distribution mode of structural surface and characteristics of lift resistance coefficient were compared. Results demonstrated that: Compared with normal wind, mesoscale typhoon intensifies the 3D aerodynamic distribution mode on structural surface of wind turbine significantly. Different from wind loads, sand loads mainly impact on 30° ranges at two sides of the lower windward region on the tower. The ratio between sand loads and wind load reaches 3.937% and the maximum sand pressure coefficient is 0.09. The coupling impact effect of strong typhoon and large sand particles is more significant, in which the resistance coefficient of tower is increased by 9.80% to the maximum extent. The maximum resistance coefficient in typhoon field is 13.79% higher than that in the normal wind field.

• Journal of the Korean Chemical Society
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• v.37 no.6
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• pp.599-603
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• 1993

Crystal structure of bis(1,2-diaminopropane)palladium(II) bis(oxalato)palladate(II) has been determined by X-ray crystallography. Crystal data: $Pd_2C_{10}H_{10}N_{4}O_{8}$, $M_W$ = 573.09, orthorhombic, space group $P_{ccn}$ (No = 56), a = 16.178(5), b = 16.381(6), c = 6.685(2)$\{AA}$, V = 1771.6 $\{AA}^3$, $M_W$W = 573.09, $D_c$ = 2.014 g${\cdot}c\;m^{-3}$, Z = 4, T = 294K, F(000) = 1056.0 and $\mu$ = 20.466 c$m^{-1}$. The intensity data were collected with $Mo-K\alpha$ radiation (${\lambda}$ = 0.7107 $\AA)$ on an automatic four-circle diffractometer with a graphite monochromater. The structure was solved by Patterson method and refined by full matrix least-squares methods using Pivot weights. The final R and S values were R = 0.065, $R_W = 0.059, R_{all}$ = 0.065 and S = 4.315 for 605 observed reflections. Both cation and anion complexes are essentially planar and have dihedral angle of $18(l)^{\circ}$ between thier planes. In the crystal structure, they do not have the Magnus's salt type mixed stacks; instead, the complex anions form regular stacks along the c-axis with the M-M bond length of $3.343(5)\AA$ and their stacks are surrounded by the complex cations through hydrogen bonds with the nitrogen-oxygen distances of 2.94(3) and $3.31(4)\AA.$

• Korean Journal of Crystallography
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• v.6 no.2
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• pp.118-124
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• 1995

The crystal structure of an iodine sorption complex of vacumm-dehydrated Ag+ and Ca2+ exchanged zeolite A(a=12.174(3)Å) has been determined at 21℃ by single-crystal X-ray diffraction techniques in the cubic space group Pm3m. The crystal was prepared by flow method for three days using exchange solution in solution in which mole ratio of AgNO3 and Ca(NO3)2 was 1:150 with total concentration of 0.05 M. The complex was prepared by dehydration at 360℃ and 2×10-6 Torr for 2 days, followed by exposure to about 14.3 Torr of iodine vaporat 80℃ for 24 hours. Full-matrix least-squares refinement converged to the final error indices of R1=0.082, R2=0.068 using 122 reflections for which I > 3σ(I). Two Ag+ ions, 1.1 Ag+ ions, and 4.45 Ca2+ ions per unit cell are located on three different three-fold axes associated with 6-ring oxygens. Two Ag+ ions per unit cell are in the large cavity, 1.399(4)Å from the (111) plane of three oxygens. Another 1.1 Ag+ ions are found at opposite sites. Six iodine molecules are sorbed per unit cell. Each I2 molecule approaches a framework oxide ion axially (O-I=3.43(2)Å, I-I=2.92Å, I-I-O;166.1(3)°), by a charge transfer complex interaction. Two Ag+ ions make a close approach to the iodine molecules (Ag-I ; 2.73(2)Å).

• Journal of the Korean Chemical Society
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• v.18 no.2
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• pp.97-109
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• 1974

The crystal and molecular structure of sulfaguanidine monohydrate, $C_7H_{10}N_4O_2S{\cdot}H_2O$, was determined from visually estimated intensity data from Weissenberg photographs. The crystal data are monoclinic, space group $P2_1$/c with four molecules in a unit cell of dimensions, ${\alpha}=7.57{\pm}0.03,\;b=5.44{\pm}0.02,\;c=24.76{\pm}0.06{\AA},\;{\beta}=91.0{\pm}0.2^{\circ}$. The structure has been solved by an interpretation of a Patterson map and with a help of a direct procedure on a projection. The parameters were refined isotropically by block-diagonal least-squares methods using 1542 observed independent reflections to give R = 0.14. By hydrogen bonding a guanidyl nitrogen of a sulfaguanidine molecule is linked to the sulfonyl oxygens of the other molecules indirectly through two different water molecules. The role of water molecule is both a donor and an acceptor in hydrogen-bonding formation and these hydrogen bonds are tetrahedrally oriented. The hydrogen-bonding networks form infinite molecular layers parallel to (001) plane.

• Geophysics and Geophysical Exploration
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• v.5 no.4
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• pp.236-249
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• 2002

We have extended the three-dimensional (3-D) resistivity imaging algorithm to cover the 3-D resistivity tomography problem, where resistivity data are acquired using electrodes installed in several boreholes as well as at the earth surface. The imaging algorithm consists of the 3-D finite element forward modeling and least-squares inversion scheme, where the ACB (Active Constraint Balancing) is adopted to enhance the resolving power of the inversion. Sensitivity analysis with numerical verifications shows that 3-D resistivity tomography is a very appealing method and can be used to get 3-D attitude of subsurface structures with very high-resolution. Moreover, we could accurately handle the topography effect, which could cause artifacts in the resistivity tomography. In the application of 3-D resistivity tomography to the real field data set acquired at the quarry mine, we could derive a very reasonable and accurate image of the subsurface.

• Journal of Korea Water Resources Association
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• v.48 no.6
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• pp.491-500
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• 2015

In order to improve the runoff estimation accuracy of the Natural Resources Conservation Service (NRCS) curve number (CN) model, this study incorporated rainfall and maximum potential retention as contributors for initial abstraction. The modification was proposed based on 658 rank-order data of rainfall and subsequent runoff from 15 watersheds. The NRCS-CN model (M1), one of its inspired modified model (M2), and the proposed model (M3) were analyzed employing different CN approaches. Using tabulated, calculated and least squares fitted CNs ($CN_T$, $CN_C$, $CN_{LSF}$, respectively), the models' performances were evaluated based on Root Mean Square Error (RMSE), Nash-Sutcliffe Efficiency (NSE), and Percent Bias (PBIAS). Applications of model M1, M2, and M3, respectively exhibited watershed cumulative mean [RMSE (23.60, 18.12, 16.04), NSE (0.54, 0.73, 0.79), and PBIAS (36.54, 20.25, 12.00)]. Similarly, using CNC (for M1 and M2 model) and $CN_{LSF}$ (for M3 model), the performance of three models respectively were assessed based on watershed cumulative mean [RMSE (17.17, 15.88, 13.82), NSE (0.76, 0.80, 0.85), and PBIAS (3.06, 4.47, 0.11)]. The proposed model (M3) that linked all of the NRCS-CN variants showed more statistically significant agreement between the observed and estimated data.

• Journal of The Korean Society of Grassland and Forage Science
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• v.31 no.4
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• pp.415-422
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• 2011

This study evaluated the feasibility of using a portable near infrared reflectance spectrometer working in the 900~1,600 nm range for the measurement of quality-related parameters (moisture, pH, Acid detergent fiber (ADF), Neutral detergent fiber (NDF), Crude protein (CP), lactic acid) in intact silage. The calibration result for the Phazir (handheld, Polychromix) was compared with the result for the Spectrastar (Lab. based, Unity). A total of 67 Italian ryegrass silages were used to build calibration models using different spectral signal pre-treatments and the partial least squares regression (PLS) method. The good calibration statistics in two instruments was obtained for moisture content of Italian ryegrass silages with over $R^2$ = 0.95. The Phazir spectrometer was less accurate in measuring of ADF, NDF and CP contents. The Spectrastar instrument yielded greater precision for pH and lactic acid content; statistic values were over $R^2$ = 0.82 and the standard error of calibration (SEC) = 0.21% and 0.24%. Thus, the NIR measurement of forage quality in the field by portable NIR analyzers was shown not to be feasible, but additional investigations are required to discern the key instrumental and operational parameters that may influence the portable NIR measurement.

• Journal of the Korean GEO-environmental Society
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• v.11 no.2
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• pp.33-42
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• 2010

The main objective of this study was to offer informations about the current conditions of stream sediments and to evaluate biochemical methane potentials of stream sediments from the urban streams in Busan city using conventional BMP tests. First we select total 5 urban streams and collect sediment samples. Then, COD, proximate analysis, volatile solid, organic carbon content and elemental analysis were conducted to determine characteristics of the sediments. Results show that COD, volatile solid and organic carbon content are determined in the range of $15.20{\sim}75.07mg\;g^{-1}$, 2.34~11.54% and 1.28~34.21%, respectively. Also, several biochemical methane potential tests were performed in a laboratory. As a result, pH values of the reactors generally increased and then stabilized at 7.11~7.35. In addition, C/N ratio, ultimate methane and carbon dioxide yield (mL/g VS) and biodegradability (%) were determined to 1.05~10.27, 10.1~179.4, 10.3~34.4 and 4.0~30.1, respectively. For the determination of the correlations between ultimate methane yield and ultimate carbon dioxide yield, C/N ratio, COD, volatile solid and organic carbon content, a linear model was fitted to the data using a least-squares algorithm. As a result, except for COD ($r^2=0.7586$) and volatile solid ($r^2=0.7876$), Linear model was well fitted to each data with good values of the correlation coefficient ($r^2=0.9795{\sim}0.9858$). Finally, we propose empirical equations, which contain C/N ratio or TOC, for the prediction of ultimate methane yield for the urban streams in Busan city.