• Biotechnology and Bioprocess Engineering:BBE
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• v.7 no.1
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• pp.6-9
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• 2002

In this work we have investigated the feasibility of virus clearance by flocculation and tangential flow microfiltration. Chinese hamster ovary cell feed streams were spiked with minute virus of mice and then flocculated using cationic polyelectrolytes prior to tangential flow microfiltration. Our results indicate that flocculation prior to microfiltration leads to more than 100 fold clearance of minute virus of mice particles in the permeate. Today, validation of virus clearance is a major concern in the manufacture of biopharmaceutical products. Frequently new unit operations are added simply to validate virus clearance thus increasing the manufacturing cost. The results obtained here suggest that virus clearance can be obtained during tangential flow microfiltration. Since tangential flow microfiltration is frequently used for bioreactor harvesting this could be a low cost method to validate virus clearance.

• The Journal of Korea Robotics Society
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• v.5 no.2
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• pp.127-134
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• 2010

In this paper, a hybrid semi-3D path planning algorithm combining Virtual Tangential Vector(VTV) and fuzzy control is proposed. 3D dynamic environmental factors are reflected to the 2D path planning model, VTV. As a result, the robot can control direction from 2D path planning algorithm VTV and speed as well depending on the fuzzy inputs such as the distance between the robot and obstacle, roughness and slope. Performances and feasibilities of the suggested method are demonstrated by using Matlab simulations. Simulation results show that fuzzy rules and obstacle avoidance methods are working properly toward virtual 3D environments. The proposed hybrid semi-3D path planning is expected to be well applicable to a real life environment, considering its simplicity and realistic nature of the dynamic factors included.

• Tunnel and Underground Space
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• v.28 no.5
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• pp.426-441
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• 2018

Recently, the generalized Hoek-Brown (GHB) failure criterion has been actively employed in various rock engineering calculations, but the analytical form of the corresponding Mohr failure envelope is not available, making it difficult to extend the application of the GHB criterion. In order to overcome this disadvantage, this study proposes a new method to express the tangential friction angle as an explicit function of normal stress by invoking the polynomial best-fitting to the relationship between normal stress and tangent friction angle implied in the GHB failure function. If this normal stress - tangential friction angle relationship is best-fitted with linear or quadratic polynomial function, it is possible to find the analytical root for tangential friction angle. Subsequently, incorporating the root into the relationship between shear stress and tangential friction angle accomplishes the derivation of the approximate Mohr envelope for the GHB criterion. It is demonstrated that the derived approximate Mohr failure envelopes are very accurate in the entire range of GSI value.

• Journal of Korean Neurosurgical Society
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• v.39 no.5
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• pp.366-369
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• 2006

Objective : There are various surgical approaches to far-lateral lesions in the L5-S1 intervertebral space. Of these is the validity of a paramedian tangential approach is being investigated in this study. Methods : A retrospective study was conducted on 25 patients who had been diagnosed as having a far-lateral L5-S1 disc herniations, osteophyte, costal process hypertrophy, and had undergone a paramedian tangential approach from November 1999 through December 2003. The degree of symptoms and improvement were compared via the visual analog pain scale, before and after surgery. Results : This study included 4 males and 21 females with a mean age of $62{\pm}11.8$ years old. The average follow-up period after surgery was $8.2{\pm}2.7$ months. The visual analog pain scale taken before surgery was $6.7{\pm}1.1$ points, while the post-surgical scale was $2.4{\pm}0.9$ points showing a significant degrease [p < 005]. There were no complications that developed during surgery. Conclusion : A paramedian tangential approach is less invasive in the soft tissue than that of the median approach. This approach may effectively reduce nerve root compression and expand intervertebral foramens, and is devoid of the risk of spinal instability after surgery. The authors suppose that a paramedian tangential approach is quite an effective technique to relive compression in the far-lateral L5-S1 intervertebral space.

• Tunnel and Underground Space
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• v.24 no.5
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• pp.366-372
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• 2014

The generalized Hoek-Brown (H-B) function provides a unique failure condition for a jointed rock mass, in which the strength parameters of rock mass are deduced from the intact values by use of the GSI value. Since it is actually the only failure criterion which accounts for the rock mass conditions in a systematic manner, the generalized H-B criterion finds many applications to the various rock engineering projects. Its nonlinear character, however, limits more active usage of this criterion. Accordingly, many attempts have been made to understand the generalized H-B condition in the framework of the M-C function. This study presents the closed-form expression relating the tangential cohesion to the tangential friction angle, which is derived by the non-dimensional stress transformation of the generalized H-B criterion. By use of the derived equation, it is investigated how the relationship between the tangential cohesion and friction angle of the generalized H-B criterion varies with the quality of rock masses. When only the variation of GSI value is considered, it is found that the tangential friction angle decreases with the increase of GSI, while the tangential cohesion increases with GSI value.

• The Journal of Korean Society for Radiation Therapy
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• v.24 no.2
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• pp.183-188
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• 2012

Purpose: The concern of improving the quality of life and reducing side effects related to cancer treatment has been a subject of interest in recent years with advances in cancer treatment techniques and increasing survival time. This study is an analysis of differing scattered dose to the contralateral breast using common different treatment techniques. Materials and Methods: Eclipse 10.0 (Varian, USA) based $30^{\circ}$ EDW (Enhanced dynamic wedge) plan, $15^{\circ}$ wedge plan, $30^{\circ}$ wedge plan, Open beam plan, FiF (field in field) plan were established using CT image of breast phantom which in our hospital. Each treatment plan were designed to exposure 400 cGy using CL-6EX (VARIAN, USA) and we measured scattered dose at 1 cm, 3 cm, 5 cm, 9 cm away from medial side of the phantom at 1 cm depth using ionization chamber (FC 65G, IBA). We carried out measurement by separating effect of medial tangential field and lateral tangential field and analyze. Results: The evaluation of scattered dose to contralateral breast, $30^{\circ}$ EDW plan, $15^{\circ}$ wedge plan, $30^{\circ}$ wedge plan, Open beam plan, FIF plan showed 6.55%, 4.72%, 2.79%, 2.33%, 1.87% about prescription dose of each treatment plan. The result of scattered dose measurement by separating effect of medial tangential field and lateral tangential field results were 4.94%, 3.33%, 1.55%, 1.17%, 0.77% about prescription dose at medial tangential field and 1.61%, 1.40%, 1.24%, 1.16%, 1.10% at lateral tangential field along with measured distance. Conclusion: In our experiment, FiF treatment technique generates minimum of scattered dose to contralateral breast which come from mainly phantom scatter factor. Whereas $30^{\circ}$ wedge plan generates maximum of scattered doses to contralateral breast and 3.3% of them was scattered from gantry head. The description of treatment planning system showed a loss of precision for a relatively low scatter dose region. Scattered dose out of Treatment radiation field is relatively lower than prescription dose but, in decision of radiation therapy, it cannot be ignored that doses to contralateral breast are related with probability of secondary cancer.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.41-42
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• 2012

• Journal of the Korean Mathematical Society
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• v.54 no.4
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• pp.1163-1173
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• 2017

In this paper, we introduce the condition (I) (cf. Section 2) and prove that there is no nontrivial tangential holomorphic vector field of a certain hypersurface of infinite type in ${\mathbb{C}}^2$.

• Honam Mathematical Journal
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• v.40 no.4
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• pp.719-732
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• 2018

In this manuscript, hybrid fixed point results for four maps using (E.A) and tangential properties in the setting of metric space are studied. Application to system of functional equations is also studied.

• Bulletin of the Korean Mathematical Society
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• v.56 no.3
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• pp.675-680
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• 2019

We, in this note, decompose the invariant Laplacian of the unit complex ball of ${\mathbb{C} }^n$ by the radial part and tangential part as ${\tilde{\Delta}}={\tilde{\Delta}}_{rad}+{\tilde{\Delta}}_{tan}$. We give several properties and interpretations involved with this decomposition.