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1

Mechanical behavior of parallel pipelines under foundation pit excavation

Han C., Ma J., Zhang J.

Engineering Transactions

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2018

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Vol. 66, iss. 1

93--106

EN

In order to study the effect of foundation pit excavation on mechanics of parallel pipeline, a pipeline-soil interaction model was established based on the finite element principle. The deformation of the pipeline by the foundation pit excavation were analyzed. Effect regulations of parallel distance, pipeline parameters and foundation pit parameters on the deformation of the pipeline were studied. The results show that there are two maximum stress areas in pipeline under the action of excavation. The upper and lower surfaces of the pipeline also appear the large stress area. The pipeline has horizontal and vertical displacements. With the increasing of the parallel distance, the deformation of the nearest pipeline increases, but the deformation of the farthest pipeline decreases. With the increasing of the radius-thickness ratio and distance between the foundation pit and the nearest pipeline, the deformation of the pipeline decreases. With the decreasing of the foundation pit width, the deformation of the pipeline decreases. Effect of the foundation pit’s length on the pipeline is not obvious.

2

OGLE-2017-BLG-1434Lb: Eighth q<1×10-4 Mass-Ratio Microlens Planet Confirms Turnover in Planet Mass-Ratio Function

Udalski A., Ryu Y.-H., Sajadian S., Gould A., Mróz P., Poleski R., Szymański M. K., Skowron J., Soszyński I., Kozłowski S., Pietrukowicz P., Ulaczyk K., Pawlak M., Rybicki K., Iwanek P., Albrow M. D., Chung S. -J., Han C., Hwang K.-H., Jung Y. K., Shin I.-G., Shvartzvald Y., Yee J. C., Zang W., Zhu W., Cha S.-M., Kim D.-J., Kim H.-W., Kim S.-L., Lee C.-U., Lee D.-J, Lee Y., Park B.-G., Pogge R. W., Bozza W., Dominik M., Helling C., Hundertmark M., Jørgensen U. G., Longa-Peña P., Lowry S., Burgdorf M., Campbell-White J., Ciceri S., Evans D., Jaimes R. F., Fujii Y. I., Haikala L. K., Henning T., Hinse T. C., Mancini L., Peixinho N., Rahvar S., Rabus M., Skottfelt J., Snodgrass C., Southworth J., von Essen C.

Acta Astronomica

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2018

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Vol. 68, No. 1

1--42

EN

We report the discovery of a cold Super-Earth planet (mp=4.4±0.5 M⊕) orbiting a low-mass (M=0.23±0.03 M⊙) M dwarf at projected separation a⊥=1.18±0.10 a.u., i.e., about 1.9 times the distance the snow line. The system is quite nearby for a microlensing planet, DL=0.86±0.09 kpc. Indeed, it was the large lens-source relative parallax πrel=1.0 mas (combined with the low mass M) that gave rise to the large, and thus well-measured, "microlens parallax" πE∝(πrel/M)1/2 that enabled these precise measurements. OGLE-2017-BLG-1434Lb is the eighth microlensing planet with planet-host mass ratio q<1×10-4. We apply a new planet-detection sensitivity method, which is a variant of "V/Vmax", to seven of these eight planets to derive the mass-ratio function in this regime. We find dN/d lnq ∝ qp, with p=1.05+0.78 -0.68, which confirms the "turnover" in the mass function found by Suzuki et al. relative to the power law of opposite sign n=-0.93±0.13 at higher mass ratios q≳2×10-4. We combine our result with that of Suzuki et al. to obtain p=0.73+0.42 -0.34.

3

OGLE-2017-BLG-0373Lb: A Jovian Mass-Ratio Planet Exposes A New Accidental Microlensing Degeneracy

Skowron J., Ryu Y.-H., Hwang K.-H., Udalski A., Mróz P., Kozłowski S., Soszyński I., Pietrukowicz P., Szymański M. K., Poleski R., Ulaczyk K., Pawlak M., Rybicki K., Iwanek P., Albrow M. D., Chung S.-J., Gould A., Han C., Jung Y. K., Shin I.-G., Shvartzvald Y., Yee J. C., Zang W., Zhu W., Cha S.-M., Kim D.-J., Kim H.-W., Kim S.-L., Lee C.-U., Lee D.-J, Lee Y., Park B.-G., Pogge R. W.

Acta Astronomica

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2018

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Vol. 68, No. 1

43--61

EN

We report the discovery of microlensing planet OGLE-2017-BLG-0373Lb. We show that while the planet-host system has an unambiguous microlens topology, there are two geometries within this topology that fit the data equally well, which leads to a factor 2.5 difference in planet-host mass ratio, i.e., q=1.5×10-3 vs. q=0.6×10-3. We show that this is an "accidental degeneracy" in the sense that it is due to a gap in the data. We dub it "the caustic-chirality degeneracy". We trace the mathematical origins of this degeneracy, which should enable similar degenerate solutions to be easily located in the future. A Bayesian estimate, based on a Galactic model, yields a host mass M=0.25+0.30 -0.15 M⊙ at a distance DL=5.9+1.3 -1.95 kpc. The lens-source relative proper motion is relatively fast, μ=9 mas/yr, which implies that the host mass and distance can be determined by high-resolution imaging after about 10 years. The same observations could in principle resolve the discrete degeneracy in q, but this will be more challenging.

4

Determination of the average maintenance time of CNC machine tools based on type II failure correlation

Shen G., Zeng W., Han C., Liu P., Zhang Y.

Eksploatacja i Niezawodność

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2017

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Vol. 19, no. 4

604--614

EN

An average maintenance time calculation method based on components failure correlation analysis is proposed to revise the traditional system maintenance time. This paper focus on complex system type II fault correlation, using the Decision-making trial and evaluation laboratory / Interpretative structural model method to divide the fault level of components. And the copula connection function is introduced to calculation of failure rate function of failure correlation components. In addition, the system maintenance time model is established by synthesizing the failure rate function of each unit of the system. Moreover, the average maintenance time under the minimum number of failures is determined. This method shows that the minimum average maintenance time of the proposed system is more reasonable than the traditional one and provides the basis for system and component reliability design.

PL

W artykule zaproponowano metodę obliczania średniego czasu konserwacji, opartą na analizie korelacji uszkodzeń elementów składowych systemu. Metoda ta ma na celu rewizję tradycyjnego czasu konserwacji systemu. Głównym tematem pracy jest korelacja awarii typu II występujących w systemach złożonych. Elementy systemu podzielono ze względu na poziom uszkodzenia przy użyciu metody DEMATEL w połączeniu z interpretacyjnym modelowaniem strukturalnym. Funkcję intensywności skorelowanych uszkodzeń elementów systemu obliczono za pomocą funkcji łączącej (kopuły). Dodatkowo, opracowano model czasu konserwacji systemu poprzez syntezę funkcji intensywności uszkodzeń każdej jednostki systemu. Ponadto, określono średni czas konserwacji dla minimalnej liczby uszkodzeń. Metoda ta pokazuje, że minimalny średni czas konserwacji proponowanego systemu jest korzystniejszy niż tradycyjnie przyjęty i stanowi podstawę do projektowania niezawodności systemu i jego składowych.

5

Recovery Of Valuable Metals In Tin-Based Anodic Slimes By Carbothermic Reaction

Han C., Kim Y.-M., Son S. H., Choi H., Kim T. B., Kim Y. H.

Archives of Metallurgy and Materials

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2015

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Vol. 60, iss. 2B

1213--1216

EN

This study investigated the recovery of anodic slimes by carbothermic reaction in the temperature range of 973~1,273K and amount of carbon as a function of time. Tin anodic slime samples were collected from the bottom of the electrolytic cells during the electro-refining of tin. The anodic slimes are consisted of high concentrated tin, silver, copper and lead oxides. The kinetics of reduction were determined by means of the weight-loss measurement technique. In order to understand in detail of carbothermic reaction, thermodynamic calculation was carried out and compared with experiments. From thermodynamic calculation and experiment, it was confirmed that Sn-based anodic slime could be reduced by controlling temperature and amount of carbon. However, any tendency between the reduction temperature and carbon content for the reduction reaction was not observed.

6

Oxide Formation In Metal Injection Molding Of 316L Stainless Steel

Jang J. M., Lee W., Ko S.-H., Han C., Choi H.

Archives of Metallurgy and Materials

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2015

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Vol. 60, iss. 2B

1281--1285

EN

The effects of sintering condition and powder size on the microstructure of MIMed parts were investigated using water-atomized 316L stainless steel powder. The 316L stainless steel feedstock was injected into micro mold with micro features of various shapes and dimensions. The green parts were debound and pre-sintered at 800°C in hydrogen atmosphere and then sintered at 1300°C and 1350°C in argon atmosphere of 5torr and 760torr, respectively. The oxide particles were formed and distributed homogeneously inside the sample except for the outermost region regardless of sintering condition and powder size. The width of layer without oxide particles are increased with decrease of sintering atmosphere pressure and powder size. The fine oxides act as the obstacle on grain growth and the high sintering temperature causes severe grain growth in micro features due to larger amount of heat gain than that in macro ones.

7

High Purity Tungsten Spherical Particle Preparation From WC-Co Spent Hard Scrap

Han C., Na H., Choi H., Kim Y.

Archives of Metallurgy and Materials

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2015

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Vol. 60, iss. 2B

1507--1509

EN

Tungsten carbide-cobalt hard metal scrap was recycled to obtain high purity spherical tungsten powder by a combined hydrometallurgy and physical metallurgy pathway. Selective leaching of tungsten element from hard metal scrap occurs at solid / liquid interface and therefore enlargement of effective surface area is advantageous. Linear oxidation behavior of Tungsten carbide-cobalt and the oxidized scrap is friable to be pulverized by milling process. In this regard, isothermally oxidized Tungsten carbide-cobalt hard metal scrap was mechanically broken into particles and then tungsten trioxide particle was recovered by hydrometallurgical method. Recovered tungsten trioxide was reduced to tungsten particle in a hydrogen environment. After that, tungsten particle was melted and solidified to make a spherical one by RF (Ratio Frequency) thermal plasma process. Well spherical tungsten micro-particle was successfully obtained from spent scrap. In addition to the morphological change, thermal plasma process showed an advantage for the purification of feedstock particle.

8

Double Step Sintering Behavior Of 316L Nanoparticle Dispersed Micro-Sphere Powder

Jeon B., Sohn S. H., Lee W., Han C., Kim Y. D., Choi H.

Archives of Metallurgy and Materials

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2015

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Vol. 60, iss. 2B

1155--1158

EN

316L stainless steel is a well-established engineering material and lots of components are fabricated by either ingot metallurgy or powder metallurgy. From the viewpoints of material properties and process versatility, powder metallurgy has been widely applied in industries. Generally, stainless steel powders are prepared by atomization processes and powder characteristics, compaction ability, and sinterability are quite different according to the powder preparation process. In the present study, a nanoparticle dispersed micro-sphere powder is synthesized by pulse wire explosion of 316L stainless steel wire in order to facilitate compaction ability and sintering ability. Nanoparticles which are deposited on the surface of micro-powder are advantageous for a rigid die compaction while spherical micro-powder is not to be compacted. Additionally, double step sintering behavior is observed for the powder in the dilatometry of cylindrical compact body. Earlier shrinkage peak comes from the sintering of nanoparticle and later one results from the micro-powder sintering. Microstructure as well as phase composition of the sintered body is investigated.

9

An iterative method based on 1D subspace for projective reconstruction

Liu S., Peng Y., Zeng Z., Han C.

Opto-Electronics Review

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2011

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Vol. 19, No. 1

89-94

EN

Heyden et al. introduced an iterative factorization method for projective reconstruction from image sequences. In their formulation, the projective structure and motion are computed by using an iterative factorization based on 4D subspace. In this paper, the problem is reformulated based on fact that the x, y, and z coordinates of each feature in projective space are known from their projection. The projective reconstruction, i.e., the relative depths w and the 3D motion, is obtained by a simple iterative factorization based on 1D subspace. This allows the use of very fast algorithms even when using a large number of features and large number of frames. The experiments with both simulate and real data show that the method presented in the paper is efficient and has good convergency.

10

A velocity measurement method based on scaling parameter estimation of chaotic system

Liu L., Hu J., He Z., Han C., Li H., Li J.

Metrology and Measurement Systems

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2011

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Vol. 18, nr 2

275-281

EN

In this paper, we propose a new method of measuring the target velocity by estimating the scaling parameter of a chaos-generating system. First, we derive the relation between the target velocity and the scaling parameter of the chaos-generating system. Then a new method for scaling parameter estimation of the chaotic system is proposed by exploiting the chaotic synchronization property. Finally, numerical simulations show the effectiveness of the proposed method in target velocity measurement.