• Journal of the Korean Wood Science and Technology
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• v.43 no.1
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• pp.122-134
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• 2015

This study was conducted to investigate the potential of torrefied larch wood as a raw material of pellets. First of all, larch chip was torrefied at the temperatures of 230, 250 and $270^{\circ}C$ for 30, 50 and 70 min. Secondly, moisture content, moisture absorption, higher heating value and ash content of the torrefied chip were measured to examine the effects of torrefaction conditions on the fuel characteristics of larch. Thirdly, surfaces of the torrefied chip were observed by light microscope (LM), field emission scanning microscope (FE-SEM) and SEM-energy dispersive spectroscopy (EDXS). With the increases of torrefied temperature and time, contents of lignin increased and those of hemicellulose reduced. Moisture content of torrefied larch chip was greatly lower than that of non-torrefied chip. Moisture absorption of the torrefied chip decreased as torrefaction temperature increased. As torrefaction temperature increased, higher heating value and ash content of larch chip increased. However, durability of torrefied-larch pellets was remarkably lower comparing to non-torrefied-larch pellets. When surface of larch chip was observed by LM and FE-SEM, surface color and cell wall of the chip was getting darker and more collapsed with the increases of torrefaction conditions. Through the analysis of SEM-EDXS, distribution and quantity of lignin existing on the surface of larch chip increased with the increases of torrefied conditions. In conclusion, $270^{\circ}C$/50 min might be an optimal condition for the torrefaction of larch with the aspect of fuel characteristics, but torrefaction condition of $230^{\circ}C$/30 min should be considered according to the durability of torrefied-larch pellets.

• Korean Journal of Heritage: History & Science
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• v.46 no.1
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• pp.208-227
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• 2013

Twenty-seven bronze bowls excavated from the Goryo burial complex at Deobu-gol were examined for their microstructure and chemical composition to characterize the bronze technology practiced by commoners at the time. Results showed that the objects examined can be classified into four groups: 1) objects forged out of Cu-near 22%Sn alloys and then quenched; 2) objects cast from Cu-below 10% Sn alloys containing lead; 3) objects cast from Cu-10%~20% Sn alloys containing lead and then quenched; 4) objects forged out of Cu-10~20% Sn alloys containing lead and then quenched. This study revealed that the fabrication technique as determined by alloy compositions plays an important role in bronze technology. The use of lead was clearly associated with the selection of quenching temperatures, the character of inclusions and the color characteristics of bronze surfaces. It was found that the objects containing lead were quenched at temperatures of $520^{\circ}{\sim}586^{\circ}C$ while those without lead were quenched at the range of $586^{\circ}{\sim}799^{\circ}C$. The presence of selenium in impurity inclusions was detected only in alloys containing lead, suggesting that the raw materials, Cu and Sn, used in making the lead-free alloys for the first group were carefully selected from those smelted using ores without lead contamination. Furthermore, the addition of lead was found to have significant effects on the color characteristics of the surface of bronze alloys when they are subjected to corrosion during interment. In leaded alloys, corrosion turns the surface light green or dark green while in unleaded alloys, corrosion turns the surface dark brown or black. It was found that in fabrication, the wall thickness of the bronze bowls varies depending on the application of quenching; most of the quenched objects have walls 1mm thick or below while those without quenching have walls 1mm thick or above. Fabrication techniques in bronze making usually reflect social environments of a community. It is likely that in the late Goryo period, experiencing lack of skilled bronze workers, the increased demand for bronze was met in two ways; by the use of chief lead instead of expensive tin and by the use of casting suitable for mass production. The above results show that the Goryo bronze workers tried to overcome such a resource-limited environment through technological innovations as apparent in the use of varying fabrication techniques for different alloys. Recently, numerous bronze objects are excavated and available for investigation. This study shows that with the use of proper analytical techniques they can serve as a valuable source of information required for the characterization of the associated technology as well as the social environment leading to the establishment of such technology.

• Journal of Yeungnam Medical Science
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• v.15 no.1
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• pp.75-96
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• 1998

The local arrangement of sensory nerve cell bodies and nerve fibers in the brain stem, spinal ganglia and nodose ganglia were observed following injection of cholera toxin B subunit(CTB) and wheat germ agglutinin-horseradish peroxidase(WGA-HRP) into the rat intestine. The tracers were injected in the stomach(anterior and posterior portion), duodenum, jejunum, ileum, cecum, ascending colon or descending colon. After survival times of 48-96 hours, the rats were perfused and their brain, spinal and nodose ganglia were frozen sectioned ($40{\mu}m$). These sectiones were stained by CTB immunohistochemical and HRP histochemical staining methods and observed by dark and light microscopy. The results were as follows: 1. WGA-HRP labeled afferent terminal fields in the brain stem were seen in the stomach and cecum, and CTB labeled afferent terminal fields in the brain stem were seen in all parts of the intestine. 2. Afferent terminal fields innervating the intestine were heavily labeled bilaterally gelalinous part of nucleus of tractus solitarius(gelNTS), dorsomedial part of gelNTS, commissural part of NTS(comNTS), medial part of NTS(medNTS), wall of the fourth ventricle, ventral border of area postrema and comNTS in midline dorsal to the central canal. 3. WGA-HRP labeled sensory neurons were observed bilaterally within the spinal ganglia, and labeled sensory neurons innervating the stomach were observed in spinal ganglia $T_2-L_1$ and the most numerous in spinal ganglia $T_{8-9}$. 4. Labeled sensory neurons innervating the duodenum were observed in spinal ganglia $T_6-L_2$ and labeled cell number were fewer than the other parts of the intestines. 5. Labeled sensory neurons innervating the jejunum were observed in spinal ganglia $T_6-L_2$ and the most numerous area in the spinal ganglia were $T_{12}$ in left and $T_{13}$ in right. 6. Labeled sensory neurons innervating the ileum were observed in spinal ganglia $T_6-L_2$ and the most numerous area in the spinal ganglia were $T_{11}$ in left and $L_1$ in right. 7. Labeled sensory neurons innervating the cecum were observed in spinal ganglia $T_7-L_2$ and the most numerous area in the spinal ganglia were $T_{11}$ in left and $T_{11-12}$ in right. 8. Labeled sensory neurons innervating the ascending colon were observed in spinal ganglia $T_7-L_2$ in left, and $T_9-L_4$ in right. The most numerous area in the spinal ganglia were $T_9$ in left and $T_{11}$ in right. 9. Labeled sensory neurons innervating the descending colon were observed in spinal ganglia $T_9-L_2$ in left, and $T_6-L_2$ in right. The most numerous area in the spinal ganglia were $T_{13}$ in left and $L_1$ in right. 10. WGA-HRP labeled sensory neurons were observed bilaterally within the nodose ganglia, and the most numerous labeled sensory neurons innervating the abdominal organs were observed in the stomach. 11. The number of labeled sensory neurons within the nodose ganglia innervating small and large intestines were fewer than that of labeled sensory neurons innervating stomach These results indicated that area of sensory neurons innervated all parts of intestines were bilaterally gelatinous part of nucleus tractus solitarius(gelNTS), dorsomedial part of gelNTS, commissural part of NTS (comNTS), medial part of NTS, wall of the fourth ventricle, ventral border of area postrema and com NTS in midline dorsal to the central canal within brain stem, spinal ganglia $T_2-L_4$ and nodose ganglia. Labeled sensory neurons innervating the intestines except the stomach were observed in spinal ganglia $T_6-L_4$. The most labeled sensory neurons from the small intestine to large intestine came from middle thoracic spinal ganglia to upper lumbar spinal ganglia.

• Childhood Kidney Diseases
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• v.8 no.2
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• pp.186-194
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• 2004

Purpose: Membranoproliferative glomeulonephritis(MPGN) has been diagnosed in an increasing number of asymptomatic cases. These cases have been detected by school urinary screening test even though the total cases of MPGN show a decreasing trend. We have analyzed the clinical and pathological characteristics of children with MPGN according to the clinical manifestations at the time of disease presentation. Methods: A total of 18 patients who had been diagnosed with idiopathic MPGN by percutaneous renal biopsy from January 1990 to February 2004 were involved in our study. The patients were divided into 2 groups as the school urinary screening(A) group and the symptomatic(S) group according to the clinical manifestations at the time of disease presentation. Results: Out of the total 18 patients, 8(44.4%) were in the S group and 10(55.6%) were in the A group. The mean serum total protein, albumin and $C_3$ levels in the S group were significantly lower than those levels of the A group, respectively($4.9{\pm}1.2\;g/dL,\;vs\;7.0{\pm}0.5\;g/dL\;P=0.002,\;2.8{\pm}0.9\;g/dL\;vs.\;4.1{\pm}0.3\;g/dL\;P=0.002,\;63.9{\pm}36.4\;mg/dL\;vs.\;100.8{\pm}39.5\;g/dL\;P=0.041$). The mean total protein amount of 24 hour collected urine in the S group were significantly higher than that of the A group($3684.0{\pm}2601.3\;mg/m^2\;vs.\;559.4{\pm}4.6.9\;mg/m^2$, respectively, P=0.001). Hypocomplementemia was observed in 11(61.1%) out of 18 patients at the time of disease onset, 7(87.5%) in the S group and 4(40%) in the A group. However the hypocomplementemia was decreased in 6(33.3%) out of 18 patients at the time of final follow-up, 3(37.5%) in the S group and 3(30%) in the A group. According to the pathologic type, hypocomplementemia was observed 8 patients(61.5%) with type I disease, 1 patients (100%) with type II disease, 2 patients(50%) in type III disease at the disease onset, but 4 patients(30.8%) in type I disease, 1 patient(100%) in type II disease, 1 patient(33.3%) with type III disease at the time of last follow-up. The incidence of cellular crescent formation and tubular atropy. as observed on light microscopy, were higher in the S group compared to the A group. Mean grade of capillary wall thickening and, mesangial proliferation were significantly higher in the S group. Conclusion: MPGN, as diagnosed in patients with only asymptomatic urinary abnormalities, has been increasing, it is more frequent in asymptomatic patients than in patients with presenting symptoms. Our result suggests that MPGN should be considered in the renal biopsy diagnosis regardless of serum $C_3$ level when urinary abnormalities are found by school urinary screening test.