• Korean Journal of Veterinary Research
• /
• v.11 no.1
• /
• pp.59-63
• /
• 1971

Current interest in ${\gamma}$-aminobutyric acid (GABA) has arisen from the convergence of several independent line of investigation leading to the demonstration that this and related substances are normal products of brain metabolism and that GABA has an important physiological action upon brain function as well as upon certain peripheral nervous structures. The interest for neurophysiologists has been enhanced by the importance of the discovery for the role of humoral mediator of synaptic transmission or regulator of neuronal activity in the central nervous system, particularly if it may shed some elight upon the nature of central inhibitory processes. In accordance with such an interest and importance, this work was performed in order to standardize the normal content as a preliminary investigation of so-called night active and daytime active animals GABA content in their brains when they are exposed to light and darkness. The method, through which the estimation has made in this work, was paper chromatographic method developed by Maynert and Klingman for the estimation of GABA content in animal tissues. The results obtained are summerized as follows: 1) GABA content in the cerebral cortex of house rat ranged from 90 to $310{\mu}g/gm$ of wet weight. 2) The content of GAGA ranging from 130 to $510{\mu}g/gm$ of wet weight was occurred from midbrain of the rat. 3) GABA content was ranged from 30 to $150 {\mu}g/gm$ of wet weight of the rat cerebellum. 4) The contents of fowl cerebral cortex, midbrain, and cerebellum are estimated as ranging 230-590, 250-620, $50-280{\mu}g/gm$ of wet weight, respectively. As a result, it may be concluded that among three brain tissues of both animals the midbrain is the highest region in GABA content. Fowl brain, on the other side, contains more higher GABA content than the house rat brain does.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2012.10a
• /
• pp.945-946
• /
• 2012

• East Asian mathematical journal
• /
• v.36 no.2
• /
• pp.229-251
• /
• 2020

Problem Based learning(PBL) is a teaching and learning method to increase mathematical ability and help achieving mathematical concepts and principles through problem solving using the learner's mathematical prerequisite knowledge. In addition, the recent instructional situations or environments have focused on the learner's self construction of his learning and its process. In spite of such a quite attention, it is not easy to apply and execute PBL program actually in class. Especially, there are some difficulties in actually applying and practicing PBL in the areas of mathematics education in not only secondary school but also in college. Its reason is that in order to conduct PBL instruction constantly in real or experimental class there is no more concrete and detailed instructional content during the consistent and long period. However, to whom is related to mathematics education including instructors called scaffolders, investigation and recognition on the degree of the learner's acquisition of mathematical thinking skills and strategies is an very important work. By the reason, in this study, the instructional content was to be explored and developed to be conducted during 15 weeks in one semester, which was based on Problem Based Learning environment by the subject of the theories relevant to mathematics education in the college of education.

• Journal of Information Processing Systems
• /
• v.10 no.4
• /
• pp.543-554
• /
• 2014

It is difficult for mobile learners to maintain a high level of concentration when learning content for more than an hour while they are on the move. Despite the attention span issue, many m-learning systems still provide their mobile learners with the same content once used in e-learning systems. This has called for an investigation to identify the suitable characteristics of the m-learning environment. With this in mind, we have conducted a survey in hopes of determining the requirements for developing more suitable m-learning content. Based on the results of the survey, we have developed a content model comprised of two types: a segment type and a supplement type. In addition, we have implemented a prototype system of the content model for Apple iPhones and Android smartphones in order to investigate a feasibility study of the model application.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.10 no.1
• /
• pp.43-48
• /
• 2010

Proctor test A or D method of compaction is the most common laboratory test for investigation of subgrade soil characteristics, however, compression type using roller is used in the field. The differences between laboratory and field compaction have considerable error as application to subgrade soil properties of laboratory test. The investigation of compacted soil is carried into effect to solve the problem. The gyratory compactor which is made to reproduce the field density of asphalt mixture, coming from traffic loads, has an advance to compact it similar to arrangement of field aggregate particles. This gyratory compactor has several problems of investigation of compacted soil, because it has designed to make initial asphalt specimens. The main objectives of this research are grasping problems when compacted soil test using the gyratory compactor and showing solutions. It has made a comparative study of difference of the percentage of water content and weight, which are before and after compaction, about the pressure of compaction, frequency of compaction and speed of compaction. And it also has investigated finding maximum percentage of water content which not occur change of percentage of water content after compaction and searching how has an effect on drawing compaction curve.

• Journal of Pharmaceutical Investigation
• /
• v.6 no.2
• /
• pp.58-68
• /
• 1976

120 tablets of 25mg phenformin hydrochloride tablet and 4mg chlorpheniramine maleate tablet, respectively, were assayed and analyzed to obtain basic data on the content uniformity of domestic pharmaceuticals. All of the tablets of phenformin hydrochloride and that of chlorpheniramine maleate were met the requirements of the test for weight variation and content but no regularity was found in the content unformity specifications. In case of chlorpheniramine maleate tablets, standard deviation of active ingredient content of B maker was 4.1% and that of C maker 7.1%.

• 보존과학연구
• /
• s.21
• /
• pp.177-206
• /
• 2000

In the study of iron artifacts, microstructure investigation is an indispensable step to find out the manufacturing method and skill. The iron weapons that we have excavated and investigated at the ruins of Gohyun Castle site, Hadong-gun, Kyungnam Province are traced to the era of Choson Dynasty. By sampling specimens of some artifacts, we have made microstructure investigation and component analysis of them. For microstructure investigation we used metallographic microscopes, and for component analysis we used the methods of C/S analysis and Inductively coupled plasma emission spectrometry (ICP) analysis which is designed to verify components and contenets of a very small amount elememt. Microstructure of the artifacts is mainly divided into three parts. Inner part is Widmanstatten, a typical overheated structure, upon which we can see another part with fine grains and with extremely small quantities of carbon. And on the surface, there is a carbonized part. When the shape is formed through forging process at a high temperature the carbon content of the surface is getting down and the grains come to be finer. Next, carbonizing process is to be done for hardening the surface, which is followed by cooling process. Cooling rates seem to be different from artifacts to artifacts. All artifacts have clearly distinguishable grain boundaries in their unique structure. Since this kind of structure is rarely found, it seems to offer a clue to find out the manufacturing method. The outcome of component analysis is almost the same with that of microstructure investigation. As is demonstrated by C/S analysis, carbon content is 0.39-1.24% and sulfur is contained 0.0005-0.010%.

• Structural Engineering and Mechanics
• /
• v.90 no.5
• /
• pp.493-504
• /
• 2024

This paper presents the methodology and results for the investigation of the structural safety of 40 aged underground water tanks to support the weight of photovoltaic (PV) systems that were supposed to be placed on their roof reinforced concrete (RC) slabs. The investigation procedure included (1) review of available documents; (2) visual inspection of the roof RC slabs; (3) carrying out a series of nondestructive (ND) tests; and (4) analysis of results. Out of the 40 tanks, eleven failed the visual inspection phase and were discarded from further investigation. The roof RC slabs of the tanks that passed the visual inspection were subjected to a series of ND tests that included infrared thermography, impact echo, ultrasonic pulse velocity (UPV), Schmidt hammer, concrete core compressive strength, and water-soluble chloride content. The NDT results proved that eight more tanks were not suitable to support the PV systems. Based on the results of the visual inspection and testing, a probabilistic decision-making criterion was established to reach a decision regarding the structural integrity of the roof slabs. The study concluded that the condition of the drainage filter was essential in protecting the tanks and its intact presence can be used as a strong indication of the structural integrity of the roof RC slabs.

• Geomechanics and Engineering
• /
• v.9 no.2
• /
• pp.261-273
• /
• 2015

In the present investigation, a series of laboratory compaction and unconfined compressive strength laboratory tests has been performed. To determine the effect of compaction energy, type of sand, and fly ash content, compaction tests have been performed with varying compaction energy ($2700kJ/m^3-300kJ/m^3$), types of sand, and fly ash content (0% to 40%) respectively. From the experimental results, it has been found that the optimum value of unconfined compressive strength obtained for a sand-fly ash mixture comprised of 65% sand and 35% fly ash. Based on the data obtained in the present investigation, a linear mathematical model has been developed to predict the OMC of sand-fly ash mixture.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2005.11a
• /
• pp.367-370
• /
• 2005

In this study, air meter method and capacitance measurement method to apply economically at quality control of ready-mixed concrete among various unit water content measurement technique was selected. Then, it was evaluated estimating performance of unit water content according to the change of water-binder ratio and unit water content. Also, it was examined influence about error occurrence of unit water content by change of properties of used materials. Finally, based on this study, it was proposed fundamental data to utilize measurement technique of unit water content to quality control. of ready-mixed concrete in construction field.