• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.18 no.2
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• pp.95-102
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• 2012

Background: The purpose of this study was to find out influence of using portable mobile devices in human body. Method: The subjects were consisted of the normal persons (19 males and 20 females). These subjects were consisted of three groups according to test time. The A group (12 persons - 6 males, 6 females) tests 5 minutes, the B group (14 persons - 7 males, 7 females) tests 10 minutes, and the C group (13 persons - 6 males, 7 females) tests 15 minutes. Before test, sight, quickness and balance were measured, after test revision, quickness, balance were measured and checked pain scale. Results: The results were as follows. 1. Sight, quickness and balance were decreased and pains were increased after using portable mobile devices than before using these. 2. According to duration of using the portable mobile devices, sight, quickness and balance was not a statistically significant difference, the entire upper body pain was a statistically significant difference. When viewed as part of the pain, shoulder, lower back, and wrist pain were a statistically significant difference, but the neck and elbow were not a statistically significant difference. 3. The influence of vision according to distance of using Portable mobile devices was no statistically significant difference. In addition, less than 20cm distance using equipment group ("Ga") and the group ("Na") which exceeded 20cm in between the sight were not statistically significant difference, Influence of pain according to distance of using Portable mobile devices we-re no statistically significant differences. Conclusion: Using portable mobile devices affect human body on the elements of the biomechanics.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.5
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• pp.369-375
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• 2000

To find a quick test procedure for soil nitrate concentration, two methods, i.e. "Nitracheck 404" reflectometer (Eijkelkamp, Netherlands) with nitrate test strip and a portable colorimeter "Hanna Ion Specific meter(USA) with a color development reagent, were tested for twenty soils with different nitrate contents ranged between from $10mg\;kg^{-1}$ to $340mg\;kg^{-1}$. The standard deviation, coefficient of variability, and recovery from these quick test procedures were compared with those measured by conventional Kjeldahl distillation method and nitrate ion electrode method. The nitrate concentration measured by portable colorimeter method was higher in soils with low concentration and lower in soils with high concentration than those measured by conventional methods. However, concentrations measured by test strip reflectometer method was showed the similar coefficient of variability and recovery as those by conventional methods for all soil samples. From the experimental results in this study, the test strip reflectometer method was thought to be recommendable one revealed the satisfied results for accuracy, quickness, and simplicity for field test of soil nitrate concentration.