• The Korean Journal of Physiology
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• v.21 no.1
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• pp.1-12
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• 1987

There is evidence that the effect of extracellular $Ca^{2+}$ on heart rate is temperature-dependent: at $38^{\circ}C$ excess $Ca^{2+}$ induces positive chronotropic response, whereas at $30^{\circ}C$ there is no significant chronotropic effect of $Ca^{2+}$. The cause of this temperature-dependency, however, remains still unclear. Therefore, this study was undertaken to investigate the chronotropic effect of external $Ca^{2+}$ at different temperature in the isolated rabbit atria and in the small strips of SA node cut perpendicularly to crista terminalis. In the isolated atria, the $Ca^{2+}$ effect was temperature-dependent: at $35^{\circ}C$ excess $Ca^{2+}$ evoked positive chronotropic response, while at $30^{\circ}C$ there was no significant changes in sinus rate. On the contrary, in the small SA strips external $Ca^{2+}$ induced negative chronotropic effect. At $35^{\circ}C$ changes in $Ca^{2+}$ concentration from 2 to 4, 6, and 10 mM decreased the sinus rate by $2.7{\pm}1.6%$, $11.2{\pm}3.7%$ and $23.2{\pm}8.1%$ respectively. Lowering the temperature to $30^{\circ}C$, the negative chronotropic effect of $Ca^{2+}$ became greater. With intracellular microelectrodes transmembrane potential was recorded in the small SA strips at $30^{\circ}C$, $35^{\circ}C$ and $38^{\circ}C$. As temperature increased from 30 to $38^{\circ}C$, sinus rate was accelerated by $13/min/^{\circ}C$, $APD_{50}$(action ptential duration from peak to 50% repolarization) decreased by $5\;msec/^{\circ}C$, and amplitude of action potential was slightly decreased. With an increase in $Ca^{2+}$ concentrations from 0.5 to 6 mM, overshoot increased and MDP decreased. These $Ca^{2+}$ effects on the overshoot and MDP of action potentials were not altered by temperature. But the $Ca^{2+}$ effects on the rates of diastolic depolarization, systolic depolarization and repolarization were modified by temperature. Discrpancy of the chronotropic effects of $Ca^{2+}$ between isolated atria and small SA strips was discussed.

• Transactions of Materials Processing
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• v.14 no.8 s.80
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• pp.655-660
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• 2005

• Nuclear Engineering and Technology
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• v.50 no.8
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• pp.1266-1276
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• 2018

In this paper, three-dimensional neutronic calculations were performed in order to calculate the dependency of CRW on the temperature of fuel and moderator and the moderator void. Calculations were performed using the known MTR_PC computer codes in the core configuration 61 of TRR. The dependency of CRW on the fuel temperature in the range of $20-340^{\circ}C$ and the moderator temperature of each control rods were studied. Based on the positions of the control rods, the calculations were performed in three different cases, named case A, B and C. By the results, the worth of each control rods increases by increasing of the coolant temperature in all methods, however, the total CRW is somewhat independent of the fuel temperature. In addition, the results showed that the variation of CRW versus density depends on the positions of the control rods and the most change in CRW in the coolant temperature, $20-100^{\circ}C$ (279 pcm), belongs to SR4. Finally the effect of void on CRW was studied for different void fraction in coolant. The most worth change is about $2 for 40% void fraction related to SR1 and SR3 in case B. For 40% void fraction, the total CRW increases about $7.5, $6 and $7 in cases, A, B and C, respectively.

• Journal of Industrial Technology
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• v.20 no.A
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• pp.39-44
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• 2000

Highly viscous biopolymer from alkali-tolerant Bacillus sp. was purified and its solution properties were investigated. The intrinsic viscosities for crude biopolymer and biopolymers purified by dialysis or CPC(cetylpyridinium chloride) treatment were 58.24, 73.60 and 42.18 dL/g, respectively. The intrinsic viscosity of biopolymer showed the maximum value at the neutral pH but it was decreased remarkably at the alkaline or acidic pH. Biopolymer exhibited the property of polyelectrolyte, showing the sharp decrease of intrinsic viscosity by the addition of NaCl. Intrinsic viscosity of dilute solution at the low NaCl concentration was exponentially dependent on temperature and its temperature dependency was increased with NaCl concentrations. The chain stiffness, coil overlap parameter, and critical concentration were 0.09, 5.25 and 0.07g/dL, respectively. Temperature dependency on intrinsic viscosity of biopolymer solution was different each other at $45^{\circ}C$. Flow activation energies at temperatures above $45^{\circ}C$ were constant, while those at temperatures below $45^{\circ}C$ increased with increase of added NaCl concentration.

• Journal of the Korean earth science society
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• v.24 no.6
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• pp.558-567
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• 2003

The regional dependency of cloud-radiative forcing at the top of atmosphere is studied using ERBE (Earth Radiation Budget Experiment), ISCCP (International Satellite Cloud Climatology Project) and NCEP/NCAR (National Centers for Environmental Prediction/National Center for Atmospheric Research) reanalysis data for 60 months from January 1985 to December 1989 over tropical ocean. In the interannual time scale, the dependency of cloud-radiative forcing on the sea surface temperature over the equatorial eastern Pacific ocean is about 7.4Wm$^{-2}$K$^{-1}$ for longwave radiation and about -4.4Wm$^{-2}$K$^{-1}$ for shortwave radiation, respectively. This shows that the net cloud-radiative forcing due to the increase of sea surface temperature over the equatorial eastern Pacific ocean heats the atmosphere. But the dependency is reversed over tropical oceans with -3.4Wm$^{-2}$K$^{-1}$ for longwave and 1.9WmWm$^{-2}$K$^{-1}$ for shortwave radiation, indicating that the net cloud-radiative forcing cools the atmosphere over tropical oceans. In raw data including seasonal cycle, the dependency of cloud-radiative forcing over the equatorial eastern Pacific ocean is very similar to that in interannual time scale in both the magnitude and the sign. But the dependency of cloud-radiative forcing on the sea surface temperature over tropical oceans is about 0.2Wm$^{-2}$K$^{-1}$ for longwave and 2.7Wm$^{-2}$K$^{-1}$ for shortwave radiation, respectively. These results represent that the role of seasonal cycle on the cloud radiative forcing is gradually more important than role of interannual time scale as the ocean area is broadening from the tropical central Pacific to the tropical ocean.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.6
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• pp.533-540
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• 2012

Rubber laminated bearings with lead core are highly affected by changes in temperature because key materials which are rubber and lead have temperature dependencies. In this study, two full scale LRB(D800, S=5) are manufactured and temperature dependency tests on shear properties are accomplished. The shear properties at the 3rd cycle are used at $-10^{\circ}C$, $0^{\circ}C$, $10^{\circ}C$, $20^{\circ}C$, $30^{\circ}C$, $40^{\circ}C$ respectively. The double shear configuration, simultaneously testing two pieces, is applied for compression shear test in order to minimize the friction effects due to the test machine, described in ISO 22762-1:2010. Characteristic strength, post-yield stiffness, effective stiffness, equivalent damping ratio are estimated and presented coefficient due to the temperature changes.

• Nuclear Engineering and Technology
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• v.49 no.6
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• pp.1287-1300
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• 2017

Based on the observation that ignoring the angle dependency of multigroup resonance cross sections within a fuel pellet would result in nontrivial underestimation of the spatial self-shielding of flux, a parametrized spectral superhomogenization (SPH) factor library (PSSL) method is developed as a practical means of resolving the problem. Region-wise spectral SPH factors are calculated by the normal and transport corrected SPH iterations after ultrafine group slowing down calculations over various light water reactor pin-cell configurations. The parametrization is done with fuel temperature, U-238 number density, fuel radius, moderator source represented by ${\Sigma}_{mod}V_{mod}$, and the number density ratio of resonance nuclides to that of U-238 in a form of resonance interference correction factors. The parametrization is successful in that the root mean square errors of the interpolated SPH factors over the fuel regions of various pin-cells are within 0.1%. The improvement in reactivity error of the PSSL method is shown to be superior to that by the original SPH method in that the reactivity bias of -200 pcm to -300 pcm vanishes almost completely. It is demonstrated that the environment effect takes only about 4% in the reactivity improvement so that the pin-cell based PSSL method is effective in the assembly problems.

• Korean Journal of Health Education and Promotion
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• v.11 no.2
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• pp.125-145
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• 1994

The objectives of this study were to characterize the health status, the requirement of home nursing care, and dependency of daily life of the elderly so that the result could be used to provide basic data necessary for establishing home nursing care practices. The study subjects were 249 elders over 65 years old who resided at home in low income areas of three districts in Pusan. The field survey was conducted from December 27, 1993 through January 27, 1994, with a structured questionnaire. Statistical analysis was done by X²-test and Student's T-test using SPSS/PC/sup +/ program. The result were as follows; 1. Alcohol drinking rate was 50.0% for men and 27.7% for women, and cigarette smoking rate was 77.8% for men and 27.1% for women. 92.9% of elders aged 65-75 exercised regularly as compared to 81.9% of elders aged 75 and over(p<0.05). 2. 63.9% of male and 85.9% of female elders had chronic diseases showing singnificant differences(p<0.01), and both sexes had 1.7 kinds of chronic diseases in average; musculoskeletal diseases were the most common in 25.7%, while 6.8% of the elderly had cardiovascular diseases. 3. Partially movable elderly was 6.9% for men and 6.8% for woman, showing 47.1% of causes being cerebrovascular accidents. 4. The home nursing requirement was the highest for medication(66.3%), intramuscular injection(53.8%), and measurement of blood pressure·body·temperature·pulse rate(47.0%). 5. Among Physical Activities of Daily Life, bathing(10.4%) and movement(4.0%) showed high dependency rates, and among Instrumental Activities of Daily Life, phone calling(25.3%), shopping(24.5%), going out by bus(22.5%) showed high dependency rates. 6. For five categories of home nursing showing high requirements such as physical health examination, blood pressure·temperature·pulas rate measurements, medication, and intravascular injection, the requirements were different by age groups, education, and marital status(p<0.05).

• Bulletin of the Korean Chemical Society
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• v.30 no.2
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• pp.285-286
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• 2009

• 전기의세계
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• v.22 no.2
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• pp.45-50
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• 1973

Amorphous semiconducting diodes from As Te Ge systm of which resitivity are 10$^{6}$ -10$^{8}$ .ohm.-cm order, are made and they exhibited several conducting states. A high conductivity, low conductivity and memory state are reported. Temperature dependency of the specimens are widerange. According to the procedure and cooling method, specimens are made easily or not. Threshold voltage of switching and memory diodes is in proportional to compositonal quantity of Arsenic. Threshold voltage is changed widely according to ambient temperature. Threshold voltage of #132 is 620V at 25.deg. C, 70V at 100.deg. C.