• Geomechanics and Engineering
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• v.22 no.6
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• pp.519-528
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• 2020

A mathematical wetting model is usually used to predict the deformation of core wall rockfill dams induced by the wetting effect. In this paper, a series of wetting triaxial tests on a rockfill was conducted using a large-sized triaxial apparatus, and the wetting deformation behavior of the rockfill was studied. The wetting strains were found to be related to the confining pressure and shear stress levels, and two empirical equations, which are regarded as the proposed mathematical wetting model, were proposed to express these properties. The stress and deformation of a core wall rockfill dam was studied by using finite element analysis and the proposed wetting model. On the one hand, the simulations of the wetting model can estimate well the observed wetting strains of the upstream rockfill of the dam, which demonstrated that the proposed wetting model is applicable to express the wetting deformation behavior of the rockfill specimen. On the other hand, the simulated additional deformation of the dam induced by the wetting effect is thought to be reasonable according to practical engineering experience, which indicates the potential of the model in dam engineering.

• Journal of the Microelectronics and Packaging Society
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• v.26 no.3
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• pp.1-6
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• 2019

Wettability is an important factor to decide solderability of solder, flux, other soldering-related materials and soldering conditions. The wettability also affects the reliability of solder joint. Wetting balance test is a good method for quantitatively measuring wettability between solder and substrate. The wetting balance test is easy to reproduce the wetting experiment and to measure the wetting time and force. And this test provides wetting curve to calculate the surface tension of the molten solder. Development of new solder has been continued in accordance with various and harsh environment in the electronics industry. In this paper, the principle of wetting balance test and recent research issues including nano-composite solder are explained.

• Journal of Welding and Joining
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• v.16 no.6
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• pp.77-85
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• 1998

Effects of non-cleaning and cleaning fluxes on the wetting properties and defects at flow soldered joints were investigated. Non-cleaning flux (R-type of 3.3% solid content) and cleaning flux (RMA-type of 15% solid content) were used. Wetting test was accomplished by wetting balance method with changing surface state of wetting specimen, CU. Sn-37%Pb solder was used for wetting test and flow soldering. As experimental results, the wetting time for vertical force from the surface tension being zero was mainly affected by surface state of the wetting specimen. Non-cleaning flux had a good wettability compared with cleaning flux. In case of non-cleaning flux, conveyor speed had a great affection to defects of bridge, icicle, and poor solder.

• Journal of the Microelectronics and Packaging Society
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• v.7 no.2
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• pp.47-53
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• 2000

The fluxless wetting properties of TSM-coated glass substrate were evaluated by the wetting balance method. We could estimate the wettability of the TSM with new parameters obtained from the wetting balance test for one side-coated specimen. It was more effective in wetting to use Cu as a wetting layer and Au as a protection layer than to use Au itself as a wetting layer. The SnSb solder showed better wettability than SnAg, SnBi, and SnIn solders. The contact angle of the one side-coated glass substrate to the Pb-free solders could be calculated from the farce balance equation by measuring the static force and the tilt angle.

• Weed & Turfgrass Science
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• v.3 no.4
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• pp.336-341
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• 2014

Wetting agent is a substance that reduces the soil water repellency and causes a liquid to spread more easily into the soil. Wetting agents are well known as to improve irrigation efficiency. Phosphorus is one of the 17 essential nutrient elements and promote faster seed germination. The objective of this study was to evaluate wetting agent and P rates for fast germination and establishment of Kentucky bluegrass. Three levels of wetting agent which were 0.23, 0.46, and $0.92ml\;m^{-2}$ were applied and the P treatments were 5, 10, and $15g\;m^{-2}$. The medium and high rate of wetting agent at the high P rate had the greatest turfgrass coverage and took 28 days to reach 50% turfgrass coverage regardless of P application. Based on this study, wetting agent is effective for fast germination and establishment of Kentucky bluegrass if sufficient phosphorus is applied.

• Weed & Turfgrass Science
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• v.6 no.4
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• pp.313-321
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• 2017

Wetting agent is designed to reduce the surface tension of the liquid and spread more easily across or penetrate into the soil against water repellency. The effect of wetting agent to seed germination is not clear. Using germination enhancer is one of the methods to increase the germination speed of turfgrass seeds and to shorten establishment period. The objective of the study was to evaluate germination enhancer and wetting agent for quick establishment of various Kentucky bluegrass cultivars. The germination enhancer was used at two levels of 0.3 and $0.6ml\;kg^{-1}$ as low and high, respectively. Two levels of wetting agent were of 0.46, and $0.92ml\;m^{-2}$ as low and high, respectively. Germination enhancer has no synergistic effect with wetting agent. When quick establishment is required, selection of cultivar would be more effective instead of using germination enhancer and wetting agent. Among Kentucky bluegrass cultivars, 'Award' had the greatest turfgrass coverage for establishment and the greatest turfgrass color and quality based on the result of the study. When quick establishment is required, selection of cultivar would be more effective instead of using germination enhancer and wetting agent.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2000.04a
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• pp.74-79
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• 2000

In an attempt to estimate the wetting properties of wettable metal layers by wetting balance method, an analysis of wetting curves of the coating layer was performed. Based on the analysis, wetting properties of UBM-coated Si-plate were estimated by the new wettability indices. The wetting curves of the one and both sides-coated UBM layers have the similar shape and show the similar tendency to the temperature. So the wetting property estimation of one side coating is possible with wetting balance method. For UBM of Si-chip, Cr/Cu/Au UBM is better than Ti/Ni/Au in the point of wetting time. At general reflow temperature, the wettability of high melting point solders(Sn-Sb, Sn-Ag) is better than that of few melting point ones(Sn-Bi, Sn-In).The contact angle of the one side coated plate to the solder can be calculated from the farce balance equation by measuring the static state force and the tilt angle.

• Journal of Welding and Joining
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• v.18 no.6
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• pp.74-82
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• 2000

The fluxless wetting properties of UBM-coated Si-wafer to the binary lead-free solders(Sn-Ag, Sn-Sb, Sjn-In, Sn0Bi) were estimated by wetting balance method. With the new wettability indices from the wetting curves of one side coated specimen, the wetting property estimation of UBM-coated Si-wafer was possible. For UBM of Si-chip, Au/Cu/Cr UBm was better than au/Ni/TI in the point of wetting time/ At general reflow process temperature, the wettability of high melting point solders(Sn-Sb, Sn-Ag) was better than that of low melting point one(Sn-Bi, Sn-In). The contact angle of the one side coated Si-plate to the solder could be calculated from the force balance equation by measuring the static state force and the tilt angle.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.35 no.1
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• pp.1-7
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• 1986

The GaAs bulk single crystals are grown by the Horizontal Bridgman method. During the growth, one of the problems in Bridgman method is the boat wetting between GaAs molten and silica boat. This boat wetting may result in another nucleation to form twin crystals. In this study, We find that the optimal size for sand blasting is 320 mesh. Backfilling the ampoule with argon gas during the vaccum bake-out decreaes the boat wetting. The reaction mechanism of Ga with quartz to produce suboxide, Ga2O, and sillion is discussed.

• Journal of the Microelectronics and Packaging Society
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• v.24 no.2
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• pp.1-9
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• 2017

Recently, there has been a continuous researches on solders having sophisticated and improved performance due to demand for high-density and miniaturization of electronics, and development of solder for automotive electronics which can be used in harsh environment. When developing a new solder alloy, there is a wettability of solder on substrate for things to consider, and the wetting balance test is one of the methods for measuring that one. In this paper, the wetting balance test is introduced, and the calculus of the surface tension of solder and the contact angle between solder and substrate using wetting curve obtained is introduced too. In detail, the principle and test method of the wetting balance test, the introduction of the parameters with important meaning in the wetting curve, the method of calculating the contact angle as well as the surface tension of the solder using the shape of the solder meniscus.