• Journal of the Korean Chemical Society
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• v.23 no.3
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• pp.125-131
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• 1979

A method for calculation of two center overlap integrals for a pair of Slater type orbitals was developed by Mulliken et al. In this method the spherical polar coordinates for a pair of Slater type orbitals located at two different points are required to be transformed into a spheroidal coordinate set for calculation of two center overlap integrals. A new method, the expansion method for spherical harmonics, in which Slater type orbitals, located at two different points, are expressed in a common coordinate system has been applied for computation of two center overlap integrals. The new method for computation of two center overlap integrals is required to translate Slater type orbitals centered at two different points into the reference point for computation of two center overlap integrals. This work has been expanded the expansion method for spherical harmonics for computation of two center overlap integrals to $|3s{\g}$, $|5s{\g}$ and $|5s{\g}$. Master formulas for two center overlap integrals are derived for these orbitals, using the general expansion formulas. The numerical values of the two center overlap integrals evaluated for a hypothetical NO molecule are in agreement with those of the previous works.

• Journal of the Korean Ceramic Society
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• v.37 no.6
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• pp.576-582
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• 2000

Two type of expanding cement generally referred to as CSA with Hauyne(3CaO 3Al2O3 CaSO4) and Quick lime(CaO). Hauyne is formed to ettringite when there are presented with CaO and CaSO4, and CaO reacts wtih water to form Ca(OH)2. REcently, the mechanism of compensation and expand mortar or concrete tend to same and it has been used improving on its shrink property. The volume of cement paste varies with its water content shrink with drying and re-wetting. Concrete and mortar works are required shrinking compensation and expansion properties to reduce of potential crack. The use of expansion cement may improve on its shrinking volume changes. CSA dosages for shrinking compensation limited by cement weight, but obtained difference expansion rate with varied W/C or inorganic admixture. This paper studies expansion rate according to expansion cement dosages, water and inorganic admixtures as Silica fume. Therefor, the expansion factor has to considered before the application.

• Journal of the Korean Society for Railway
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• v.20 no.4
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• pp.500-511
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• 2017

Recently, as earthquakes have occurred in Gyeongju, interest in the stability of structures against vibration from earthquakes has increased. In Korea, the capacity of load resistance is mainly considered in the design of anchors. However, the vibration resistance characteristics of anchors have not been fully elucidated. The traditional type of anchor, which is a frictional resistance anchor, is often reported to fail due to vibration in construction procedures, such as blasting. The expansion type of anchor, on the other hand, could have more resistance to vibration but its capability of demonstrating vibratory resistance has to be investigated. In order to verify the vibratory resistance characteristics of expansion anchors against blasting and earthquake vibration, field tests and numerical analyses for seismic wave were performed. Field blasting test results show that the expansion anchor has better capability against vibratory load than does the frictional type anchor. Numerical analysis to earthquake also show that the expansion type anchor provides more resistance than does the frictional type anchor.

• Korean Journal of Agricultural Science
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• v.18 no.2
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• pp.140-147
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• 1991

This paper was performed to obtain the data applied to use of synthetic lightweight aggregate concrete affected by alkali silica reaction. The results obtained were summarized as follows : 1. The expansion of each type concrete was increased with increase of curing age, respectively. Also, at the curing age 90 days, the rate of expansion of type A, B, C and D concrete was increased 0.173%, 0.575%, 0.230% and 0.680%, respectively. Specially, the rate of expansion of type D concrete was shown 3.93 times higher than the type A concrete. The cracks width were increased with increase of expansion and at the 0.680% expansion, the maximum width was shown 0.5 mm. 2. The dynamic modulus of elasticity of each type concrete was increased with increase of curing age, respectively. At the curing age 30 days, the highest dynamic modulus of elasticity was showed at each type concrete, respectively. But, it was gradually decreased with increase of curing age at those concrete, respectively. Also, at the curing age A, B, C and D concrete was increased 24.3%, 33.7%, 28.1% and 37.0%, respectively. The rate of loss in type D concrete was shown 1.52 times higher than the type A concrete. 3. The ultrasonic pulse velocity of each type concrete was increased with increase of curing age, respectively. At the curing age 30 days, the highest ultrasonic pulse velocity was showed at each type concrete, respectively. But, it was gradually decreased with increase of curing age at those concrete, respectively. Also, at the curing age 90 days, the percentage loss of ultrasonic pulse velocity of type A, B, C and D concrete was increased 6.4%, 8.7%, 8.5% and 14.2%, respectively. The rate of loss in type D concrete was shown 2.21 times higher than the type A concrete. 4. The relation between dynamic modulus of elasticity and ultrasonic pulse velocity was highly significant. The dynamic modulus of elasticity was increased with increase and decreased with decrease of ultrasonic pulse velocity. Also, the decreasing rate of the dynamic modulus of elasticity was shown 2-7 times higher than the ultrasonic pulse velocity at each age, respectively. 5. The dynamic modulus of elasticity and ultrasonic pulse velocity were decreased with increase of expansion, and the decreasing rates were increased with increase of curing age. The increasing rate of expansion was shown higher than the decreasing rate of dynamic modulus and ultrasonic pulse velocity.

• The korean journal of orthodontics
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• v.53 no.4
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• pp.241-253
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• 2023

Objective: To evaluate the following null hypothesis: the skeletal and dentoalveolar expansion patterns in the coronal and axial planes are not different with two different types of microimplant-assisted rapid palatal expansion (MARPE) systems. Methods: Pretreatment (T0) and post-MARPE (T1) cone-beam computed tomography (CBCT) images of 32 patients (14 males and 18 females; mean age, 19.37) were analyzed. We compared two different MARPE systems. One MARPE system included the maxillary first premolars, maxillary first molars, and four microimplants as anchors (U46 type, n = 16), while the other included only the maxillary first molars and microimplants as anchors (U6 type, n = 16). Results: In the molar region of the U6 and U46 groups, the transverse expansion at the midnasal, basal, alveolar, and dental levels was 2.64, 3.52, 4.46, and 6.32 mm and 2.17, 2.56, 2.73, and 5.71 mm, respectively. A significant difference was observed in the posterior alveolar-level expansion (p = 0.036) and posterior basal-bone-level expansion (p = 0.043) between the groups, with greater posterior skeletal and alveolar expansion in the U6 group. Conclusions: Compared with the U46 group, the U6 group showed greater posterior expansion at the alveolar and basal-bone levels, with an almost parallel split. Both groups showed a pyramidal expansion pattern in the coronal view.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1344-1346
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• 1995

The interrupting capability of gas circuit breakers(GCB) are critically dependent on the pressure rise of the puffer cylinder or the thermal expansion chamber at current zero. Therefore it's very useful for the designers to know the pressure rise there at the design stage. Much effort has been done to predict the pressure rise in the puffer cylinder or the thermal expansion chamber in no-load condition. Thus, we now calculate it with reasonable accuracy with the simple programs coded by ourselves or with the commercial CFD packages. However, it has been still difficult problem to calculate it under the existence of arc. In this paper, we propose a method which can be used to predict the pressure rise in the thermal expansion chamber of thermal expansion type GCB. The method has been applied to the 25.8kV 25kA thermal expansion type model GCB and the calculated results have been compared with those from experiment.

• Journal of the Korean Vacuum Society
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• v.20 no.5
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• pp.313-321
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• 2011

The Korea Research Institute of Standards and Science (KRISS) has three major vacuum systems: an ultrasonic interferometer manometer (UIM), a static volume expansion system (SVES), and an orifice-type dynamic expansion system (ODES). For each system explict measurement model equations with multiple variables are respectively given. According to ISO standards, all these system variables errors were used to calculate the expanded uncertainty (U).

• Physical Therapy Rehabilitation Science
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• v.10 no.4
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• pp.430-437
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• 2021

Objective: The purpose of this study was to investigate the effect of 3-dimensional posture correction(3DPC) exercise program incorporating PNF respiratory muscle strengthening(RMS) exercise on spinal alignment and trunk expansion in patients with idiopathic scoliosis and the difference in intervention effect by type of idiopathic scoliosis. Design: Comparative study using paired t-test and analysis of variance measures. Methods: The subjects of this study were 5 men and 24 women diagnosed with idiopathic scoliosis with a Cobb angle greater than 10 degrees and less than 45 degrees. A 3DPC exercise program incorporating PNF RMS exercise was conducted twice a week for 1 hour per session for 6 weeks, and Cobb angle, Angle of trunk rotation, and trunk expansion were measured before and after the intervention. Results: After the intervention, Cobb angle and trunk rotation angle showed a statistically significant decrease, and trunk expansion showed a statistically significant increase. In the effect difference by type, there was a statistically significant difference in the angle of trunk rotation of the thoracic in 3C and Single Lumbar. Conclusions: In conclusion, it is thought that a 3DPC exercise program incorporating PNF RMS exercise can be effectively used in clinical practice to improve spinal alignment and trunk expansion in patients with idiopathic scoliosis.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.9
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• pp.408-413
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• 2005

This paper presents the basic design technology on the hybrid type GCB(gas circuit breakers) through the test results. The three type hybrid interrupters according to the arrangement of the thermal expansion chamber and the puffer cylinder(they are called 'serial type', ' parallel/exchanged type ,' and ' parallel/separated type ' respectively in this work) were designed and manufactured and then the tests of operating characteristics and interrupting were performed using a simplified synthetic test facility. The interruption capability with the type and the opening speed and the pressure rise which is required to interrupt were examined. The change of pressure rise with the number of interruption was given quantitatively and therefore the pressure rise can be predicted. Finally, it was shown that the interruption capability tends to increase with the increasing of opening speed in the puffer type; however, the hybrid type interrupter has a different interruption characteristic.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.3
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• pp.321-327
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• 2009

This paper studied the influences of the main design parameter-the expansion angle and the material properties of the self-expansion anterior cruciate ligament fixation device on the contact condition with the bone and the initial stability of the device. Using finite element analysis, the stress distributions of the ring part of the device and the wall of the bone tunnel were calculated. And the micro-migration of the device by the pull-out force was calculated. From the analysis results, it was found that when designing the self-expansion type anterior cruciate ligament fixation device, it is desirable to use the material having higher Young's modulus and to design the fixation device that all wedges uniformly maintain contact with bone to obtain initial stability after operation.