• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.40 no.2
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• pp.57-64
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• 2008

In general, the entire of paper mulberry bark, which is not cut into pieces with an appropriate length, have been used in the pulping. This kind of pulping method couldn't accomplish the improvement of beating and sheet forming efficiency. For this reason, we investigated the effects of the cutting length of paper mulberry bast fiber on pulping and Hanji (Korean traditional paper) properties, in order to develop high quality Hanji manufacturing process. The cutting length variation of paper mulberry white bast did not great effects on pulp yields. The pulp yields based on pulping methods were sulfomethylated pulping av. 57.4%, alkali-hydrogen peroxide pulping av. 55.4%, and alkaline pulping av. 53.5% respectively. The optical properties such as brightness, opacity, scattering coefficient, and absorption coefficient were slightly improved by the increase of paper mulberry white bast cutting length. The increase of paper mulberry white bast cutting length resulted in poor sheet formation. Physical properties such as breaking length, TEA, tear index, burst index, and folding endurance were slightly improved by the increase of cutting length. The modified pulping processes, which used sulfomethylated method and alkali-hydrogen peroxide method, showed better pulp and sheet properties than conventional alkaline pulping.

• Journal of Conservation Science
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• v.5 no.1 s.5
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• pp.94-104
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• 1996

This study was carried on paper mulberry bast fibers, which were cut in the length of it's chip by three kinds. And they cooked by sodium hydroxide (NaOH) and ammonium oxalate (AMOX), and pulping process was studied to inquire some properties of hand made papers. The results were as follows. AMOX pulps had $10\~17\%$ higher than NaOH, but amounts of the residual lignin of it's pulps and residual ash were high, and it surely can't be superior. In the freeness of pulps, AMOX pulps were higher than that of NaOH, but they showed tendency to opposite in view of relation of chip's length kinds. For the AMOX pulps, the physical characteristics test results were higher long fiber pulps than short fiber pulps. Specially, in folding endurance long fiber pulps were a very strong. NaOH pulp's physical characteristics test had shown results that were opposite of there of the AMOX pulps, if the length of the fiber is longer, the strengthts generally decreased. To get the optimum fiber's length according to use of paper and pulping method, they must be fractionate chip's length. The long fibers in NaOH pulps affected the paper quality greatly to length of chips.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.37 no.2 s.110
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• pp.1-10
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• 2005

Removal of fines from fiber furnish by fractionation improves drainage, but decreases fiber bonding in paper. Fines can be again classified by their size such as the fines that passed 150 and 400 mesh screen, respectively. A hypothesis of different properties between these two kinds of fines was tested. Four different furnishes (SwBKP, HwBKP, KOCC, and BCTMP) were refined in two levels, and all their furnish and handsheet properties were compared in respect of their fines. KOCC fines gave the slowest drainage and least contribution to breaking length while BCTMP fines the fastest drainage and the highest contribution to breaking length. Removal of the fines that passed 400 mesh screen gave high improvement in drainage and large decrease in breaking length. Only KOCC fines removal gave more positive results where there were large improvement in drainage but only small decrease in breaking length.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.34 no.2
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• pp.13-21
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• 2002

A new method for measuring fiber length and fiber coarseness was developed using image analysis technique. Measured fibers were transferred to a glass slide on a filter paper placed on a wire of the laboratory paper machine. After staining the fibers on the slide, mean fiber lengths and coarseness were measured by a commercial image analysis software, named KS400. The resultant data obtained from the image analysis displayed a close correlation with those from FS-200 and also showed excellent reproducibility as well as those from FS-200. The length of synthetic fibers over 10 mm long could be readily measured by this new analysis technique. Finally, a substantial improvement in precision for measuring fiber length and coarseness was made with less operator's effort for a given time.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.37 no.2 s.110
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• pp.78-86
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• 2005

Hwaseonji(Korean traditional paper) used for writing and painting has been made from the mulberry bast-fiber and the short-length fiber pulps, wood pulps. However, besides wood pulps, other short-length fiber pulps also can be used instead of wood pulps. Hence, this research was carried out to make the various Hwaseonjis with the different properties, using the five kinds of short-length fiber pulps respectively. The short-length fiber pulps used in this research were softwood bleached kraft pulp(SwBKP) hardwood bleached kraft pulp(HwBKP), rice-straw bleached sulfite pulp(RsBSP), bamboo bleached kraft pulp(BbBKP) and recycled pulp from vellem paper(RP). And, the mixture ratios of the mulberry bast-fiber pulp and short-length fiber pulps were 100:0, 80:20, 60:40, 40:60 and 20:80. After various Hwaseonjis were made from different mixtures mentioned above with hand-made method, physical properties and chinese ink blot property of each paper were measured. The strengthes were the highest in the Hwaseonji made from the mixture of the mulberry bast-fiber pulp and SwBKP. However, chinese ink blot property and smoothness were better when RsBSP, BbBKP or RP were mixed into the mulberry bast-fiber pulp. As a result, the various kinds of Hwaseonjis which the users can choose based on their needs were made.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.6
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• pp.994-1002
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• 2008

In this paper a novel tracking system is described, regarding the influence of shadow between array, aimed at improving the efficiency of PV tracking system. Comparing with a building site versus capacity power, domestic solar powers have a limited siting. Therefore, each array interferes with the shadow of other arrays. The loss by influence of those shadow can be compensated for by means of control algorithm of the tracking device. The paper suggests a method controlling an altitude for length which is received the shadow influence of PV array. By using an azimuth of current solar position and the length between arrays, the controller of tracking device is able to calculate the length between actual arrays and make a comparison of the shadow length at a specific time with the length between arrays. When the shadow length is longer than the length between arrays, the controller of tracking device can adjust a position by compensating error altitude of the length between arrays at an altitude of current solar position. In the paper, we develop the control algorithm able to minimize the loss caused by the influence of shadow on the PV tracking system, and compared this with conventional output system. The controller has been tested in the laboratory with proposed algorithm and shows excellent performance.

• Honam Mathematical Journal
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• v.22 no.1
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• pp.31-36
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• 2000

In this paper, we introduce the extremal length and examine its properties and consider the applications of extremal length to conformal mappings. We obtain the theorems in the connection with "the extremal length zero" and "the fundamental sequences".

• Journal of Electrical Engineering and Technology
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• v.7 no.4
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• pp.524-529
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• 2012

This paper proposes a novel control strategy of a PV tracking system considering the shadow influence. If distance of between PV arrays is not enough, shadow can be occurred to PV module. In PV system, if shadow is occurred to PV modules then PV modules operates reverses bias, and will eventually cause hot-spot and loss. To reduce loss by shadow influence, this paper proposes shadow compensation algorithm using distance between arrays and shadow length of array. The distance between arrays is calculated by using azimuth of solar, and length of array shadow is calculated using by altitude of solar. The shadow compensation algorithm proposed in this paper compares distance between arrays and length of array shadow. When the shadow length is longer than the distance between arrays, the algorithm adjusts altitude of array to avoid the shadow effects. The control algorithm proposed in this paper proves validity through compared with conventional algorithm and proposes experiment result.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1888-1891
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• 2003

In this paper, we proposed a new method to control the length of carbon nano tube in the single CNT probe. A single CNT probe was composed of a tungsten tip made by the electrochemical etching and carbon nano tube which was grown by CVD and prepared through the sonication. The two components were attached with the carbon tape. Since the length of CNT can not be controlled during the manufacturing, the post process is needed to shorten the CNT. In this paper, we proposed the method of electrochemical process. The process was done under the optical microscope and the results were checked by SEM. The diameter of the carbon nano tube used in this paper was about 130nm because the above process had to be done with the optical microscope. Using the method proposed in this paper, we can control the length of the nano tube tip.

• Journal of the Korean Society of Tobacco Science
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• v.22 no.1
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• pp.99-106
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• 2000

In order to investigate the applicability of lyocell fiber to filter paper, papper sheets were manufactured with the addition of lyocell fibers in various length(1.5 denier: 2, 3, 4mm) and content(10, 30, 50%) and their physical characters, such as fibrilation rate, adsorption efficiency of methylene blue(MB), paper formation, and crimping ability, etc, were tested. The level of main fibrilation from lyocell fiber was higher in wet beating process than that in free beating because of the higher strength of lyocell fiber compared with wood fiber. Fibrilation could be observed at the degree of beating over 30$^{\circ}$ SR in wet beating with Valley beater. The air permeability and tear factor of the paper increased and the paper formation index decreased according to the increase of fiber length. The weak binding force of lyocell fiber in spite of its higher fiber strength, might be a limitng factor in addition of lyocell fiber to the natural wood pulp in manufacturing the paper having the needed physical properties. High contents of wood pulp decreased air permeability, the breaking length, tear factor, the bursting strength, and paper formation index in paper sheets. As the contents of lyocell increased from 10% to 100%, the adsorption efficiency of MB was elevated to 1.7-7.9 times compared with that in 100% wood pulp. But the length of lyocell fiber did not affect the MB adsorption.