• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.1093-1097
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• 1996

The Substitution development of 7075-T6 Al alloy to 7050-T74 Al alloy in small arms to improve anti-stress corrosion cracking was processed along with mass productivity consideration. To meet 7050 Al alloy material characteristics Indirect extrusion type was adopted and local heating above recrystalization temperature in forging process had to be avoided. The T74 aging treatment was 12$0^{\circ}C$ -6hrs and 175$^{\circ}C$ -12hrs and was appropriate for both machanical and anti-cohesion properties. In accessment of field application test 7050Al alloy made parts of small arms showed equivalent or better performance than 7075 Al alloy.

• Wind and Structures
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• v.38 no.5
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• pp.367-379
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• 2024

Compared with traditional transmission towers, T-shaped angle towers have long cross-arms and are specially used for ultrahigh-voltage direct-current (UHVDC) transmission. Nevertheless, the wind loads of T-shaped towers have not received much attention in previous studies. Consequently, a series of wind tunnel tests on the T-shaped towers featuring cross-arms of varying lengths were conducted using the high-frequency force balance (HFFB) technique. The test results reveal that the T-shaped tower's drag coefficients nearly remain constant at different testing velocities, demonstrating that Reynolds number effects are negligible in the test range of 1.26 × 10⁴-2.30 × 10⁴. The maximum values of the longitudinal base shear and torsion of the T-shaped tower are reached at 15° and 25° of wind incidence, respectively. In the yaw angle, the crosswind coefficients of the tower body are quite small, whereas those of the cross-arms are significant, and as a result, the assumption in some load codes (such as ASCE 74-2020, IEC 60826-2017 and EN 50341-1:2012) that the resultant force direction is the same as the wind direction may be inappropriate for the cross-arm situation. The fitting formulas for the wind load-distribution factors of the tower body and cross-arms are developed, respectively, which would greatly facilitate the determination of the wind loads on T-shaped angle towers.

• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.4
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• pp.456-463
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• 2018

With the development of weapon systems by mounting various sensors, it makes important to analyze the precise functioning of sensor to external environment. In the case of small arms with magnetic sensor, the malfunction of small arms might be caused by strong external magnetic fields. In this study, the effects of magnetic sensor on external magnetic fields were analyzed, and optimal magnetic shield and shield structure were designed through M&S. In addition, the magnetic-shielding effectiveness of magnetic sensor in small arms was verified with commercial shielding materials. As a result, it was demonstrated that the Fe-Cu-Si-Nd-B with the structure of multi-layer metallic shields was shown the magnetic-shielding effectiveness of 83 % for an external permanent magnet and 19 % for an alternating magnetic field of 180 dBpT at 60 Hz, respectively.

• Journal of Korean Society for Quality Management
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• v.45 no.3
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• pp.327-333
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• 2017

Purpose: The purpose of this study is to research to protect to loss of chrome-plating of small arms barrel on high temperature in order to extend its life expectency. Methods: The reason why chrome-plating dropped out is main material is weak from heat. Therfore, to make barrel of small arms have higher heat-resistant property, nitriding for barrel before chrome-plating is needed and test of that barrel was handled to improve it. Results: Nitriding before chrome-plating is useful to protect to chrome-plating loss on high temperature. Conclusion: To protect loss of chome-plating of small arms barrel during on firing, pre-nitriding on barrel is effective finally it leads to extend to barrel's life expectency.

• PNF and Movement
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• v.12 no.4
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• pp.233-241
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• 2014

Purpose: The purpose of this study is to investigate the effects of exercising on a stable and unstable surface for a period of six weeks on the arms of female university students in their twenties. Methods: The subjects consisted of 20 female university students. The experimental group consisted of ten individuals who exercised on an unstable surface, and the control group consisted of ten individuals who exercised on a stable surface. The exercise program was composed of aerobic exercises (i.e. Back and forth movements for clapping and raising cross with both arms) and muscle-strengthening exercises (i.e. Push-ups and raising arms). We measured the subjects before the experiment and after the exercise program using the following measurements tool: a ruler and T-scan plus. The same person measured changes in arm size with a ruler three times and calculated the average to minimize any errors in measurement. We controlled the subjects to measure the amount of arm muscle with a T-scan plus. Twelve hours before the measurements were taken subjects were not permitted to exercise, and four hours before the measurements were taken subjects were not permitted to eat anything. Results: The two groups had no significant difference, but each group felt the effect of the exercise program. Conclusion: There was no difference between the experimental group and the control group. However, it was determined that the exercise had a greater effect on an unstable surface than a stable surface.

• Journal of Animal Science and Technology
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• v.49 no.5
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• pp.549-558
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• 2007

C4B and BAT2, assigned to the SLA class III region, were recently reported on relation with human diseases. The primers for RT-PCR and RACE-PCR for CDS analysis of these genes of pig were designed by aligning the CDSs of humans and mice from GenBank. After we amplified and sequenced with these primers and cDNAs, the full-length CDSs of pig were determined. The CDS lengths of C4B and BAT2 were shown as 5226 bp and 6501 bp. In addition, the identities of nucleotide sequences with human and mouse were 76% to 87%, and the identities of amino acids were 72% to 90%. After we carried out the alignment with determined CDSs in this study and pig genomic sequences from GenBank, the primers for cSNP detection in genome were designed in intron regions that flanked one or more exons. Then, we amplified and directly sequenced with genomic DNAs of six pig breeds. Four cSNPs from C4B and three 3 cSNPs from BAT2 were identified. In addition, amino acid substitution occurred in six cSNP positions except for C4248T of C4B. By the Multiplex-ARMS method, we genotyped seven cSNPs with DNA samples used for direct sequencing. We verified that this result was the same as that analyzed using direct sequencing. To demonstrate recrudescence, we performed both direct sequencing and Multiplex-ARMS on two randomly selected DNA samples. The genotype of each sample showed the same result from both methods. Therefore, seven cSNPs were identified from C4B and BAT2 and could be used as the basic data for haplotype analysis of SLA class III region. Moreover, the Multiplex-ARMS method should be powerful for genotyping of genes assigned to the whole SLA region for the xenograft study.

• Bulletin of the Korean Chemical Society
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• v.23 no.5
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• pp.688-692
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• 2002

The aminomethylation of phenols with para-substituents by the Mannich reaction has successfully been accomplished to produce the Mannich bases 2-6. The compounds 7-8 have also been synthesized in order to identify the effect of the side arms and t he macrocycle in the complex formation. Protonation constants and stability constants of the double armed diaza-18-crown-6 ethers 2-7 with metal ions have been determined by potentiometric method at 25 $^{\circ}C$ in 95 % methanol solution. Under a basic condition (pH > 8.0), the double-armed crown ethers 2-6 revealed stronger interaction with divalent metal ions than the simple diazacrown ether 1. The stability constants with these metal ions were Co 2+ < Ni2+ < Cu2+ > Zn 2+ in increasing order, which are in accordance with the order of the Williams-Irving series. The stability constants with alkali earth metal ions were Ca 2+ < Sr 2+ < Ba 2+ in increasing order, which may be explained by the concept of size effect. It is noteworthy that the hosts 2-6, which have phenolic side arms and a macrocycle, bind stronger with metal ions than the hosts 1 and 7. On the other hand, the host 8, which has phenolic side arms with a pyperazine ring,provided comparable stability constants to those with the host 3. These facts demonstrate that phenolic side arms play a more important role than the azacrown ether ring in the process of making a complex with metal ions especially in a basic condition. In particular, the log KML values for complexation of divalent metal ions with the hosts 2-6 had the sequence, i.e., 2 (R=OCH3) < 3 (R=CH3) < 4 (R=H) < 5 (R=Cl) < 6 (R=CF3). The stability constants of the hosts 5 and 6 containing an electron-withdrawing group are larger than those of the hosts 2 and 3 containing an electron-donating group. This substituent effect is attributed to the solvent effect in which the aryl oxide with an electron-donating group has a tendency to be tied strongly with protic solvents.

• The Journal of Korean Obstetrics and Gynecology
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• v.25 no.4
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• pp.38-45
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• 2012

Purpose: The purpose of this study is to find the factors that can affect the assessment on severity of cold hypersensitivity on hands and feet by comparing the temperature distribution among the seasons, the scan time and the laboratory temperature. Methods: We compared the temperature distribution of the arms and legs, according to the season and scan time on the basis of the results of Digital Infrared Thermal Imaging(DITI) conducted on 178 women who visited the hospital in summer and winter. We evaluated the correlation between the laboratory temperature and temperature distribution of the arms and legs. Results: The temperature distribution of the arms and legs was significantly different between summer and winter. The temperature distribution of the arms and legs was not significantly different according to the scan time. There was no significant correlation between laboratory temperature and the temperature distribution of the arms and legs in summer and winter. Conclusions: The diagnostic criteria to assess the severity of cold hypersensitivity on hands and feet need to be changed according to the season. The scan time and the small variation($24^{\circ}C{\sim}27^{\circ}C$) of the laboratory temperature doesn't affect the assessment of severity of cold hypersensitivity.

• Biomedical Science Letters
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• v.24 no.1
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• pp.43-49
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• 2018

Electrocardiogram (ECG) is a widely used method to diagnose electrical activity of heart. Although it is a reliable and easy method, ECG could be interfered by electrical signals. One of the interfering signals is electromyogram (EMG) that is caused by muscle contraction in any parts of the body except heart. To avoid the EMG noise, an examinee is advised to be relaxed on supine position while measuring ECG. Sometimes, patients who can't put their arms and legs down on bed due to some reasons such as cast on arms or legs necessarily have the EMG noise. But detailed information about how much of the noise could be induced by positional change of arms and legs has not been reported. Here we examined the noise by analyzing ECG data from 14 candidates, 7 males and 7 females. The ECG data was obtained using the standard 12 lead ECG. EMG noise was induced by raising arms and legs at $90^{\circ}$, $60^{\circ}$ or $30^{\circ}$. Because arms are located close to the heart, noise by the raised arms was analyzed toward left or right arm separately. All of the examinees showed similar pattern of the EMG noise. EMG noise by positional change of left or right arm was clearly monitored in different limb leads. Change of leg positions induced the noise that was monitored in aVF of augmented leads and II and III of limb leads. There was a difference in degree of the noise between male and female examinees. In addition to the EMG noise, decrease of PR interval was monitored in particular positional changes, which was prominent in male examinees. These results will enlarge fundamental understanding about EMG noise in ECG.

• Journal of the Korean Home Economics Association
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• v.40 no.11
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• pp.193-205
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• 2002

To evaluate farmers' workload during harvesting grapes in summer, this study investigated farmers' physiological, psychological responses, work postures and thermal environment around in the field. This field study was conducted in the Anseong County of Kyonggi Province at the end of August. Five career farmers (1 male, 4 females) volunteered as subjects. Three of them were over their sixties. During harvesting grapes in the field, physiological responses were monitored continuously. 1. Air temperature (T/sub a/), air humidity(H/sub a/), black globe temperature(T/sub g/), air velocity and WBGT around the grape field were 26.9℃, 77.7%RH, 32.8℃, 0.08㎧ and 26.3℃, respectively. Because farmers started the harvesting task in early morning, thermal environments weren't conditions to give farmers severe heat strain. 2. The percentage of the work postures was larger in order of standing, walking, and bending one's back posture. Particularly, the percentage of standing posture with raising both arms above shoulder of two farmers was up to 29% and 61% of the total work duration. 3. Rectal temperature (T/sub re/), mean skin temperature (T/sub sk/), clothing microclimate temperature (T/sub cl/) on the chest and the back, heart rate (HR) and energy expenditure (EE) were 37.2℃, 33.1℃, 32.0℃, 32.4℃, 88bpm and 1.3 Kca1/㎡/min respectively. In the point of these physiological results, we evaluated that the harvesting task was a moderate work. 4. All farmers expressed‘hard, hot, humid and slightly uncomfortable’ at the end of works for each subjective questionnaire. The grape harvesting tasks were not evaluated as a very hard work in the point of physiological work standards. But we considered 1) inappropriate work posture (standing posture with raising both arms above shoulder) and 2) farmers' age as burden factors. These findings suggest that adding adequate protective clothing/equipments for farmers may contribute to maintain their body temperature within the normal range, stabilize HR and decrease psychological strain.