• Korean Journal of Mathematics
• /
• 제17권4호
• /
• pp.429-436
• /
• 2009

We define a projective representation $M_1{^{\rightarrow}_{\rightarrow}}M_2{\rightarrow}M_3$ of a quiver $Q={\bullet}{^{\rightarrow}_{\rightarrow}}{\bullet}{\rightarrow}{\bullet}$ and consider their properties. Then we show that any projective representation $M_1{^{\rightarrow}_{\rightarrow}}M_2{\rightarrow}M_3$ of a quiver $Q={\bullet}{^{\rightarrow}_{\rightarrow}}{\bullet}{\rightarrow}{\bullet}$ is isomorphic to the quotient of a direct sum of projective representations $0{^{\rightarrow}_{\rightarrow}}0{\rightarrow}P,\;0{^{\rightarrow}_{\rightarrow}}P{\rightarrow\limits^{id}}P$ and $P{^{\rightarrow}_{\rightarrow}}^{e1}_{e2}P{\oplus}P{\rightarrow\limits^{id_{P{\oplus}P}}}P{\oplus}P$, where $e_1(a)=(a,0)$ and $e_2(a)=(0,a)$.

• Progress in Superconductivity
• /
• 제4권2호
• /
• pp.121-126
• /
• 2003

The single layer direct-coupled YBCO SQUID magnetometers have been fabricated and characterized for the purpose of the measurement of weak magnetic signals in unshielded environment. Two types of magnetometers have been designed and fabricated using 10 mm$\times$ 10 mm substrates. We could operate the conventional 3-mm-wide solid pickup loop magnetometers more stably than the 12-parallel-line pickup loop magnetometers in laboratory environment. We developed a first-order electronic gradiometer system using the SQUID sensors with axial displacement of 80 mm without any mechanical alignment of magnetometers. The system with a software filter using calculation of discrete Fourier transform could record clearly weak pulse signal of 100 pT in a magnetically disturbed environment.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1995년도 추계학술대회 논문집
• /
• pp.628-634
• /
• 1995

In the area of assembly process of micro-chips and electronic parts on the printed circuit board, surface mounting device(SMD) is used as a fundamental tool. Generally speaking, the motion of the SMD is based on the ball screw system operated by any type of actuators. The ball screw system is a mechanical transformer which converts the mechanical rotational motion to the translational one. Also, this system could be considered as an efficient motion device against mechanical backash and friction. Therefore a dynamic modeling and stste sensitivity analysis of the ball screw system in SMD have to be done in the initial design stage. In this paper, a simple mathematical dynamic model for this system and the sensitivity snalysis are mentioned. Especially, the bond graph approach is used for graphical modeling of the dynamic system before analysis stage. And the direct differentiation method is used for the state sensitivity analysis of the system. Finally, some trends for the state variables with respect to the design variables could be suggested for the better design based on the results on the results of dynamic and state sensitivity.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2006년도 추계학술대회
• /
• pp.153-156
• /
• 2006

The domestic solar radial ion data have been measured at 16 different sites all over the country since the beginning of 1980. It is very important that the fundamental data for the estimation and assessment of local solar radiation can be secured this project. In order to estimate available energy resource from solar radiation, it is necessary to have enough data, more than 30 years In any country. However since we have collected solar radiation(global radial ion including direct normal radiation) data only for 10 years we still need to measure insolation to secure the reliability and standardization of measured local solar radial ion data. In brief, the major activities on this R&D include rout me maintenance of the national network for insolation data measurement, evaluation of the collected data, and reliability enhancement for assessing the quality of solar radiation data as well.

• Environmental Analysis Health and Toxicology
• /
• 제29권
• /
• pp.7.1-7.8
• /
• 2014

Objectives The present study was designed to systematically characterize the denaturation and the renaturation of double stranded DNA (dsDNA), which is suitable for DNA hybridization. Methods A series of physical and chemical denaturation methods were implemented on well-defined 86-bp dsDNA fragment. The degree of each denaturation was measured and the most suitable denaturation method was determined. DNA renaturation tendency was also investigated for the suggested denaturation method. Results Heating, beads mill, and sonication bath did not show any denaturation for 30 minutes. However probe sonication fully denatured DNA in 5 minutes. 1 mol/L sodium hydroxide (alkaline treatment) and 60% dimethyl sulfoxide (DMSO) treatment fully denatured DNA in 2-5 minutes. Conclusions Among all the physical methods applied, the direct probe sonication was the most effective way to denature the DNA fragments. Among chemical methods, 60% DMSO was the most adequate denaturation method since it does not cause full renaturation during DNA hybridization.

• Journal of Biosystems Engineering
• /
• 제37권3호
• /
• pp.209-213
• /
• 2012

Purpose: This study was performed to develop a simple, disposable thin-film optical nitrate sensor. Methods: The sensor was fabricated by applying a nitrate-selective polymer membrane on the surface of a thin polyester film. The membrane was composed of polyvinylchloride (PVC), plasticizer, fluorescent dye, and nitrate-selective ionophore. Fluorescence intensity of the sensor increased on contact with a nitrate solution. The fluorescence response of the optical nitrate sensor was measured with a commercial fluorospectrometer. Results: The optical sensor exhibited linear response over four concentration decades. Conclusions: Nitrate ion concentrations in plant nutrient solutions can be determined by direct optical measurements without any conditioning before measurements.

• Clinical and Experimental Pediatrics
• /
• 제50권9호
• /
• pp.835-840
• /
• 2007

Any infant noted to be jaundiced at 2 weeks of age should be evaluated for cholestasis with measurement of total and direct serum bilirubin. With the insight into the clinical phenotype and the genotype-phenotype correlations, it is now possible to evaluate more precisely the neonate who presents with conjugated hyperbilirubinemia. Testing should be performed for the specific treatable causes of neonatal cholestasis, specifically sepsis, galactosemia, tyrosinemia, citrin deficiency and endocrine disorders. Biliary atresia must be excluded. Low levels of serum gamma-glutamyl transferase in the presence of cholestasis should suggest progressive familial intrahepatic cholestasis type 1, 2, or arthrogryposis- renal dysfunction-cholestasis syndrome. If the serum bile acid level is low, a bile acid synthetic defect should be considered. Molecular genetic testing and molecular-based diagnostic strategies are in evolution.

• 대한수학회보
• /
• 제45권1호
• /
• pp.59-66
• /
• 2008

Keskin and Harmanci defined the family B(M,X) = ${A{\leq}M|{\exists}Y{\leq}X,{\exists}f{\in}Hom_R(M,X/Y),\;Ker\;f/A{\ll}M/A}$. And Orhan and Keskin generalized projective modules via the class B(M, X). In this note we introduce X-local summands and X-hollow modules via the class B(M, X). Let R be a right perfect ring and let M be an X-lifting module. We prove that if every co-closed submodule of any projective module P contains Rad(P), then M has an indecomposable decomposition. This result is a generalization of Kuratomi and Chang's result [9, Theorem 3.4]. Let X be an R-module. We also prove that for an X-hollow module H such that every non-zero direct summand K of H with $K{\in}B$(H, X), if $H{\oplus}H$ has the internal exchange property, then H has a local endomorphism ring.

• Journal of Korean Neurosurgical Society
• /
• 제51권6호
• /
• pp.383-387
• /
• 2012

Spinal epidural abscess, if especially caused by Brucellosis is a very rare disease which is usually a consequence of spondylodiscitis. The spinal column can be affected at any joint; however, the lumbar spine is the most common region, especially at the level of the L4-5 and L5-S1. The frequency of spinal involvement usually seen at the lumbar, thoracic and cervical spine respectively. As an occupational disease in farmers, veterinaries, butchers, laboratory staff and shepherds, brucellosis can also occur by direct contact to animals and infected materials or ingestion of raw cheese, milk or unpasteurized milk products. In this study, we presented two cases with cervical spinal epidural abscess caused by brucella melitensis, which was successfully treated by surgical approach. Initial treatment was combined with antibiotic therapy after the surgery for 3 months.

• The Korean Journal of Pain
• /
• 제5권1호
• /
• pp.108-112
• /
• 1992

Pain from pelvic cancer is very difficult to manage because it's vague ness and bilateral nature. Furthermore, nerve blocks in this area are dangerous because sensory afferent nerves from pelvic viscera are adjacent to nerves that regulate bowel and bladder control, and motor nerve of lower extremities'. Bilateral lumbar sympathectomy has been used for malignant pelvic pain with little risk of neurologic complication. However it is not a specific block for pelvic visceral pain, because the lumbar sympathetic chain does not innervate pelvic viscera in a direct manner. Therefore the potentials of lumbar sympathectomy for pelvic visceral pain are attributed to caudad diffusion of neurolytic agents to the smperior hypogastric plexus. I have experienced 3 cases of superior hypogastric plexus neurolysis per se without any significant complications.