• 펄프종이기술
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• 제38권4호
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• pp.24-30
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• 2006

Formation which is an indicator of nonuniformity in fiber distribution is concerned with small scale variation in roughness, optical properties, print density, and so on. This study evaluated the formation of sheets which were made usning handsheet former and paper-machine with hydraulic headbox. Optical method and ${\beta}-ray$ method were used for formation test. The fiber type, freeness and basis weight of sheet were considered as variables. The formation of handsheet was affected by fiber type and freeness, and floe size distribution was influenced by basis weight. For machine made sheet, its formation seemed to be dependent on the hydraulic forces in headbox and former. When two formation test methods were compared, there was the highest relationship between optical formation index and normalized standard deviation from ${\beta}-ray$ method.

• 한국정밀공학회지
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• 제7권4호
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• pp.73-84
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• 1990

A burr has been defined as an undesirable projection of material formed as the result of plastic flow from a cutting or shearing operation. It is Unavoidable in all kinds of machining operation. This paper describe the burr formation mechanism which is based on the behavior of workpiece material during orthogonal machining of the clay on the milling machine. Specially in this report the rollover burr is dealt as a specific case of the chip formation in the final stage of cutting. The negative shear angle is introduced as an important features of burr formation. It is found that the burr formation process is divided into three stage-initiation, development of negative shearing, and formation of the burr with appropriate assumptions. Using above the burr formation mechanism, the size of burr can be estimated by cutting conditions.

• International Journal of Aeronautical and Space Sciences
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• 제9권1호
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• pp.31-41
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• 2008

This paper deals with the energy saving problem of the follower aircraft in the loose leader-follower formation geometry in which the lateral separation between formation members is more than a wingspan of the leader aircraft. This formation geometry offers no drag benefit, but has a strategic advantage. In the case of loose formation flight, the follower aircraft usually consumes more energy than the leader aircraft because the follower aircraft should use more thrust to maintain given formation geometry, especially during the turning phase from the outside of the leader"s flight path or join-up phase. A formation control scheme based on the energy maneuverability is proposed in this paper. To design the proposed control law, the velocity command is designed using feedback linearization for the horizontal formation geometry and then coverts it to the altitude command using the energy equation. Numerical simulation is performed to verify the effectiveness of the proposed controller.

• ETRI Journal
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• 제38권5호
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• pp.1008-1018
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• 2016

This paper presents a control scheme for the leader-following formation of multiple robots. The control scheme combines the sliding mode control (SMC) method with the nonlinear disturbance observer (NDOB) technique. The formation dynamics suffer from uncertainties because the individual robots are uncertain. Concerning such formation uncertainties, the leader-following formation dynamics are modeled. Assuming that the formation uncertainties have an unknown boundary, an NDOB-based observer was designed to estimate the formation uncertainties. A sliding surface containing the observer outputs has been defined. Regarding the sliding surface, an SMC-based controller was investigated to form uncertain robots. A sufficient condition in the sense of the Lyapunov theory was proven such that the formation system is asymptotically stable. Herein, some comparison results between the sole SMC method and the second-order SMC method are presented to demonstrate the effectiveness and feasibility of the control scheme for multiple robots in the presence of uncertainties.

• Journal of Microbiology and Biotechnology
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• 제28권1호
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• pp.77-86
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• 2018

The human pathogen and food spoiler Bacillus cereus can form biofilms that act as a persistent source of contamination, which is of public health concern. This study aimed to understand how the source of isolation might affect the behavior of biofilm formation. Biofilm formation abilities of 56 strains of B. cereus isolated from different environments, including human food poisoning, farm, and food, were determined. Crystal violet assay results revealed significant (p < 0.05) differences in biofilm formation abilities among the strains isolated from different sources only at an early stage of incubation. However, strain origin showed no impact on later stage of biofilm formation. Next, correlation of the group of isolates on the basis of their biofilm-forming abilities with the number of sessile cells, sporulation, and extracellular polymeric substance (EPS) formation was determined. The number of sessile cells and spores in biofilms was greatly influenced by the groups of isolates that formed dense, moderate, and weak biofilms. The contribution of extracellular DNA and/or proteins to EPS formation was also positively correlated with biofilm formation abilities. Our results that the source of isolation had significant impact on biofilm formation might provide important information to develop strategies to control B. cereus biofilm formation.

• 펄프종이기술
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• 제37권2호
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• pp.57-63
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• 2005

Microflute has several advantages of production cost and strength compared to board. Production technology of microflute has not been fully explored. Therefore suitability of corrugating medium for microflute shape formation was analyzed by measuring (1) lengths of corrugating medium before flute formation, (2) those after flute formation but before conditioning and (3) those after flute formation and after conditioning. The suitability of corrugating medium was better when the length change before and after conditioning after flute formation was smaller, because flute sustained its form. The suitability of corrugating medium for microflute shape formation was better when the flute height after flute formation was higher. The suitability of corrugating medium was analyzed depending on properties of corrugating medium in terms of fiber bonding strength and paper stiffness. For better microflute shape formation and its preservation it was found that fiber bonding should be increased, proper stiffness was required, and resistance to water absorption from surroundings should be increased.

• 펄프종이기술
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• 제29권2호
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• pp.76-82
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• 1997

In paper the evenness of planar distribution of mass in a small scale is called formation (orbetter:mass formation). Traditionally formation has been assessed visually, by looking the sheet of paper against transmitted light. Different kinds of optieal testers are being usd to obtain quantitative rankings htat would be independent of the observer but would well correspond to the visual assessment. However, various raw-material and process factors do influence light trans-mittance in paper and do impair the correspondence between basis weight and the optical formation measurement (or visual assessment). As the optical formation test methods do not incorporate an efficient calib ration routine, the formation of the sophisticated paper grades of today the is rather difficult to measure optically and may lead to erroneous results. It may be concluded that the optical measurement is not suitable for paper grades with high filler content. coating, heavy calendering or that are made of heavily beaten pulp, nordoes it apply for dyed or printed papers. For this reason, visual assessment and optical evaluation shoild be replaced with a measurement that gives reliable results independent on paper grode and manufacturing process. Formation measuremend based on beta radiation is suitable for all paper grades regardless to the material contents or process treatment. It is possible to measure even dyed or printed samples. Thonks to a sim ple and relioble calibration, the results are converted to real basis weight balues that remain reliable even with time. The only beta tester commercially available is the AMBERTEC Beta Formation Tester. Formation of paper does vary locally in the web. Typically there exists a formation profile, too similarly to other properties of paper. Therefore, formation should ？ ays be expressed as a mean of a sufficient amount of parallel determinations. All formation measurements should be calibrated against basis weight.

• 자원환경지질
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• 제3권1호
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• pp.17-24
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• 1970

The purpose of this report is to prepare a data for the economic evaluation on the Goobong Limestone Mine which is located at the south-eastern corner of the Yongchun Quadrangle scaled in 1:50,000. The accessibility from the mine to railroad was considered in two ways. One is to Dodam Station on Central Railway Line and the other is to reach Songjung-ni village which is near Sangyong Station on Hamback Railway Line. The distance of the former way is 26.7km and the later is 24.2km. Geologically the mine is situated near the base of the Greast Limestone Series which strikes generally $N25^{\circ}{\sim}30^{\circ}E$. The series comprises six different formations from older to younger; Pungchon Limestone Formation and Whajol Formation of Cambrian age, and Dongjum Quartzite Formation, Dumudong Formation, Maggol Limestone Formation and Goseong Formation of lower to middle Ordovician age. 82 samples; 48 from Pungchon Limestone Formation, 11 from Dumudong Formation, 15 from Maggol Limestone Formation and 8 from Goseong Formation, were taken from the series in the crossed direction to the general trend of the series as shown in geological map. They were chemically analyzed on the components of CaO, MgO, $SiO_2$, $R_2O_3(Al_2O_3+Fe_2O_3)$ and ignition loss as shown in table 2, table 3, table 4, and table 5. As seen from the tables, among the formations of the series, middle to upper parts of the Pungchon Limestone Formation and middle and upper parts of the Dumudong Formation have chemical composition as available source for the raw material of cement industry, not only that but also the part of the Pungchon Formation was highly evaluated as source for the flux of iron smelting and the raw material of carbide manufacturing because of its high purity of calcium carbonate.

• International Journal of Aeronautical and Space Sciences
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• 제10권1호
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• pp.30-36
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• 2009

Many formation guidance laws have been proposed for VAV formation flight. Since most autonomous formation flight methods require various active communication links between the vehicles to know motion information of other vehicles, damage to the receiver or the transmitter and communication delay are critical problem to achieve a given formation flight mission. Therefore, in this point of view, the method that does not need an inter-vehicle communication is preferred in the autonomous formation flight. In this paper, we first summarize the formation guidance law without an inter-vehicle communication using feedback linearization and sliding mode control proposed in previous study. We also propose the modified formation guidance law with robust disturbance observer, which can provide significantly better performance than previously mentioned guidance law in case that other vehicles maneuver with large accelerations. The robust disturbance observer can estimate uncertainties generated by acceleration of leader vehicle. By eliminating the uncertainties using the estimated uncertainties, VAVs are able to achieve the tight formation flight. The performance of the proposed approach is validated by numerical simulations.

• 한국식물병리학회지
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• 제14권5호
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• pp.413-417
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• 1998

Magnaporthe grisea, the casual agent of rice blast, requires formation of an appressorium, a dome-shaped and well melanized infection structure, to penetrate its host. Environmental cues that induce appressorium formation include hydrophobicity and hardness of contact surface and chemicals from its host. Artificial surfaces are widely used to induce appressorium formation, but frequencies of appressorium induction are not always consistent. To understand variable induction of appressorium formation in M. grisea, several factors were tested on GelBond. High levels of appressorium formation were induced over a wide range of temperature (20~3$0^{\circ}C$) and pH (4~7). spore age up to 3-week-old did not significantly affect appressorium formation, but only a few apressoria on GelBond. However, adenosine specifically inhibited appressorium formation. Adenosine inhibition of appressorium formation was restored by exogenous addition of cAMP. Germ tube tips of M. grisea maintained the ability to differentiate appressoria by chemical inducers on GelBond at least up to 16 h after conidia germination. These results suggest that environmental factors have little effect on the variable induction of appressorium formation on the artificial surface in M. grisea.