Variability of measured modal frequencies of a cable-stayed bridge under different wind conditions

Y.Q. Ni,J.M. Ko,X.G. Hua,H.F. Zhou 국제구조공학회 2007 Smart Structures and Systems, An International Jou Vol.3 No.3

A good understanding of normal modal variability of civil structures due to varying environmental conditions such as temperature and wind is important for reliable performance of vibration-based damage detection methods. This paper addresses the quantification of wind-induced modal variability of a cable-stayed bridge making use of one-year monitoring data. In order to discriminate the wind-induced modal variability from the temperature-induced modal variability, the one-year monitoring data are divided into two sets: the first set includes the data obtained under weak wind conditions (hourly-average wind speed less than 2 m/s) during all four seasons, and the second set includes the data obtained under both weak and strong (typhoon) wind conditions during the summer only. The measured modal frequencies and temperatures of the bridge obtained from the first set of data are used to formulate temperature-frequency correlation models by means of artificial neural network technique. Before the second set of data is utilized to quantify the wind-induced modal variability, the effect of temperature on the measured modal frequencies is first eliminated by normalizing these modal frequencies to a reference temperature with the use of the temperature-frequency correlation models. Then the wind-induced modal variability is quantitatively evaluated by correlating the normalized modal frequencies for each mode with the wind speed measurement data. It is revealed that in contrast to the dependence of modal frequencies on temperature, there is no explicit correlation between the modal frequencies and wind intensity. For most of the measured modes, the modal frequencies exhibit a slightly increasing trend with the increase of wind speed in statistical sense. The relative variation of the modal frequencies arising from wind effect (with the maximum hourly-average wind speed up to 17.6 m/s) is estimated to range from 1.61% to 7.87% for the measured 8 modes of the bridge, being notably less than the modal variability caused by temperature effect.

Variability of measured modal frequencies of a cable-stayed bridge under different wind conditions

Ni, Y.Q.,Ko, J.M.,Hua, X.G.,Zhou, H.F. Techno-Press 2007 Smart Structures and Systems, An International Jou Vol.3 No.3

A good understanding of normal modal variability of civil structures due to varying environmental conditions such as temperature and wind is important for reliable performance of vibration-based damage detection methods. This paper addresses the quantification of wind-induced modal variability of a cable-stayed bridge making use of one-year monitoring data. In order to discriminate the wind-induced modal variability from the temperature-induced modal variability, the one-year monitoring data are divided into two sets: the first set includes the data obtained under weak wind conditions (hourly-average wind speed less than 2 m/s) during all four seasons, and the second set includes the data obtained under both weak and strong (typhoon) wind conditions during the summer only. The measured modal frequencies and temperatures of the bridge obtained from the first set of data are used to formulate temperature-frequency correlation models by means of artificial neural network technique. Before the second set of data is utilized to quantify the wind-induced modal variability, the effect of temperature on the measured modal frequencies is first eliminated by normalizing these modal frequencies to a reference temperature with the use of the temperature-frequency correlation models. Then the wind-induced modal variability is quantitatively evaluated by correlating the normalized modal frequencies for each mode with the wind speed measurement data. It is revealed that in contrast to the dependence of modal frequencies on temperature, there is no explicit correlation between the modal frequencies and wind intensity. For most of the measured modes, the modal frequencies exhibit a slightly increasing trend with the increase of wind speed in statistical sense. The relative variation of the modal frequencies arising from wind effect (with the maximum hourly-average wind speed up to 17.6 m/s) is estimated to range from 1.61% to 7.87% for the measured 8 modes of the bridge, being notably less than the modal variability caused by temperature effect.

Emergence and Persistence of NS5A and NS3 Resistance-Associated Substitutions in HCV Genotype 1b Patients Treated with Daclatasvir and Asunaprevir

( F. Mcphee ),( D. Hernandez ),( N. Zhou ),( F. Yu ),( B. Kienzle ),( Y. Zhao ),( M. Linaberry ),( S. Noviello ),( M. L. Yu ),( S. H. Ahn ),( Y. Karino ),( K. Chayama ),( H. Kumada ) 대한간학회 2017 춘·추계 학술대회 (KASL) Vol.2017 No.1

Aims: A pooled analysis of emergent RAS was performed in HCV genotype (GT-)1b-infected patients receiving daclatasvir and asunaprevir (DCV+ASV) and the persistence of DCV- and ASV-resistant substitutions through ≥post-treatment Week (PTWK)192 was assessed to understand the RAS profile and help guide potential retreatment options. Methods: HCV GT-1b-infected patients without a sustained virologic response (SVR) and with HCV RNA ≥1000 IU/mL on or after DCV+ASV treatment were included from 5 Phase 2 and 3 studies. Baseline and post-baseline plasma samples were sequenced at a sensitivity cut-off ł20%. To determine the persistence of emergent RAS, samples at the end of study (up to PTWK48) and/or from a 3-year long-term follow-up rollover study were sequenced (sensitivity cut-off ≥20%, and ≥1% for select samples). Results: 152 DCV+ASV-treated patients without SVR met the resistance testing criteria: 89% (136/152) had NS5A and 95% (145/152) had NS3 sequences at both baseline and virologic failure (VF). NS5A and NS3 RAS emerged in 99% (134/136) and 89% (129/145), respectively, at VF (Table). Overall, 93% (142/152) of patients with VF had both NS5A and NS3 sequence data at failure, of which 77% (109/142) had RAS at L31, Y93 and D168. Emergent NS5A RAS persisted at PTWK96 (92%;24/26) and ≥PTWK192 (100;7/7compared with 22% (6/27) and 14% (1/7), respectively, for emergent NS3 RAS. Replacement of emergent NS5A and NS3 RAS observed at VF occurred in 8% (2/26) of NS5A and 74% (17/23) of NS3 sequences at PTWK96 and in 0% (0/7) of NS5A and 86% (6/7) of NS3 sequences at ≥PTWK192. Conclusions: NS5A and NS3 RAS emerged in most patients treated with DCV+ASV who experienced VF, and NS5A RAS persisted post-treatment. Therapy options for DCV+ASV treatment failures may depend on the timing of retreatment: an NS3 inhibitor-containing regimen may be possible if NS3 RAS are no longer observed, while regimens not impacted by the NS5A-L31+Y93 and NS3-D168 RAS combination would offer an immediate alternative.

High Sustained Virologic Response with Daclatasvir plus Asunaprevir in HCV GT-1b Chinese, Korean and Taiwanese without Baseline NS5A Polymorphisms

( F. Mcphee ),( L. Wei ),( Q. Xie ),( Y. Suzuki ),( J. Toyota ),( Y. Karino ),( K. Chayama ),( Y. Kawakami ),( M. L. Yu ),( S. H. Ahn ),( N. Zhou ),( H. Kumada ) 대한간학회 2016 춘·추계 학술대회 (KASL) Vol.2016 No.1

Aims: Daclatasvir (DCV) plus asunaprevir (ASV) has demonstrated highsustained virologic response (SVR) in HCV genotype (GT-)1b infection.NS5A-Y93H and NS5A-L31 resistance-associated polymorphisms(RAPs) to DCV are known to impact DCV+ASV response in GT-1b-infectedJapanese. The effect of RAPs on SVR at posttreatment week12 (SVR12) to DCV+ASV was explored in mainland Chinese, Korean,and Taiwanese.Methods: Pooled data from 2 studies of DCV (60 mg daily) + ASV(100 mg capsule, twice-daily) for 24 weeks in GT-1b-infected interferon/ribavirin-naive and -experienced patients from mainland China,Korea, and Taiwan. Similar Japanese data (4 studies; n=445) werepooled for comparison. SVR12 with versus without baseline Y93Hand/or L31 RAPs was compared by age (<65 vs ≥65 years), cirrhosisstatus, and baseline HCV-RNA.Results: SVR12 and baseline NS5A sequences were available for 282patients (126 mainland Chinese [45%〕, 80 Koreans [28%〕, 76Taiwanese [27%〕). NS5A-Y93H and/or -L31 RAPs were observed pretreatmentin 8% mainland Chinese, 14% Korean, and 18%Taiwanese patients, compared with 19% in Japanese. SVR12 in allnon-Japanese patients is shown (Figure); rates were broadly similarbetween countries and with Japanese data (Japanese: 96% overallwithout RAPs, 41% with RAPs). Responses were lower among patientswith baseline RAPs. By contrast, SVR12 in patients without RAPs washigh (92-100%), irrespective of cirrhosis, age, or baseline HCV-RNA.Conclusions: At least 95% of HCV GT-1b-infected patients from mainlandChina, Korea or Taiwan without baseline NS5A-Y93H or -L31polymorphisms who had HCV-RNA ≤7 log10 IU/mL achieved SVR12on DCV+ASV, regardless of cirrhosis status and age.

Effects of Brazing Temperature on Microstructure and High-Temperature Strength of Joints Using a Novel Fourth-Generation Nickel-Based Single Crystal Superalloy

Z. P. Zhang,J. D. Liu,K. Q. Qiu,Y. Y. Huang,J. G. Li,X. G. Wang,J. L. Liu,M. Wang,M. K. Zou,Y. Z. Zhou 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.2

A novel fourth-generation nickel-based single crystal superalloy was bonded by vacuum brazing at 1230 °C, 1260 °C and1290 °C for 60 min using a new type of Co-based filler alloy. The effects of the brazing temperature on the microstructureand mechanical properties of the brazed joint were investigated. The brazed joint was mainly composed of the non-isothermalsolidification zone (M3B2 type-boride, CrB boride, Ni3Bboride and MC carbide), isothermal solidification zone (γ and γ'Phase) and base metal. With the increase of brazing temperature, the volume fraction of borides and γ' phase in the centerof the joint decreased and increased, respectively. The high-temperature tensile test results show that the tensile strength ofthe joints was improved with increasing brazing temperature, and the maximum tensile strength of the joint was 766 MPaafter brazing at 1290 °C for 60 min. Fracture observation shows that the fracture modes of the joints were the same, whichbelongs to the typical quasi cleavage fracture. The element distribution in the joint was homogenized to a certain extent at1290 °C. The segregation of Si and Ru was found, but they were still dissolved in the γ solid solution. The experimentalresults help to better understand the microstructure characteristics of the novel fourth-generation nickel-based single crystalsuperalloy and provide guidance for further optimizing the process parameters of the brazed joint.

Effects of Fabric Surface Energy on Human Thermophysiological Responses during Exercise and Recovery

Zhou, L.Y.,Li, Y.,Chung, J.,Tokura, H.,Gohel, M.D.I.,Kwok, Y.L.,Feng, X.W. The Korean Fiber Society 2007 Fibers and polymers Vol.8 No.3

The present paper reports a study on influences of fabric surface energy of cotton and polyester garments on clothing microclimates and human thermophysiological responses during intermittent exercise and recovery. Eight healthy males wearing the garments prepared performed exercises and rest according to the following protocol: rest for 30 min, run on treadmill for total 60 min of three sessions with different intensity and duration, and then sit quietly for 30 min for recovery, all at $30^{\circ}C$ and relative humidity of 30 %, while the microclimate humidity ($H_{mc}$) and temperature ($T_{mc}$), the clothing outside surface humidity ($H_{co}$) and temperature ($T_{co}$), the skin temperatures and ear canal temperature ($T_{ear_canal})$ were measured. The garments are made of: (a) hydrophilic and hydrophobic cotton knitted fabrics, and (b) hydrophilic and hydrophobic polyester knitted fabrics. During and after exercise, for cotton, hydrophilic garment resulted in significant lower ${\Delta}H_{mc}$, ${\Delta}H_{co}$, ${\Delta}T_{mc}$, during recovery, higher ${\Delta}{\bar{T}}_{sk}$, lower ${\Delta}T_{ear_canal}$ and ${\Delta}T_{forehead}$. For polyester, hydrophilic garment resulted in significantly lower ${\Delta}H_{co}$, ${\Delta}T_{co}$, higher ${\Delta}T_{forehead}$, during E1, E2 and recovery session but lower during E3. In summary, surface energy of cotton garments had significant influences on human thermophysiological responses during exercise and recovery, and hydrophilic cotton garment was better than hydrophobic one to reduce heat stress. Surface energy of polyester garments had influences of lower significance, and hydrophilic garment appeared better than hydrophobic garment.

Use of negative capacitance to simulate the electrical characteristics in double-gate ferroelectric field-effect transistors

Y.G. Xiao,M.H. Tang,Y. Xiong,J. C. Lin,C.P. Cheng,B. Jiang,H.Q. Cai,Z.H. Tang,X.S. Lv,X.C. Gu,Y.C. Zhou 한국물리학회 2012 Current Applied Physics Vol.12 No.6

The surface potential and drain current of double-gate metal-ferroelectric-insulator-semiconductor (MFIS) field-effect transistor were investigated by using the ferroelectric negative capacitance. The derived results demonstrated that the up-converted semiconductor surface potential and low subthreshold swing S = 34 (<60 mV/dec) can be realized with appropriate thicknesses of ferroelectric thin film and insulator layer at room temperature. What’s more, a reduction gate voltage about 260 mV can be reached if the ON-state current is fixed to 600 mA/mm. It is expected that the derived results can offer useful guidelines for the application of low power dissipation in ongoing scaling of FETs.

Effects of Korea Red Ginseng on Substance Metabolism and Endocrinic Funciton in Animals

Zhou, Z.M.,Li, Z.L.,Nie, S.Q.,Li, L.X.,Sun, X.M.,Wang, Y.L.,Liang, E.H.,Li, G.Q.,Yang, L.X. The Korean Society of Ginseng 1990 Journal of Ginseng Research Vol.14 No.2

Dynamic Threshold Switching Behavior of Ge[sub 2]Sb[sub 2]Te[sub 5] and Sb-doped Ge[sub 2]Sb[sub 2]Te[sub 5] Thin Films Using Scanning Electrical Nanoprobe

Zhou, P.,Shin, Y. C.,Choi, B. J.,Choi, S.,Hwang, C. S.,Lin, Y. Y.,Lv, H. B.,Yan, X. J.,Tang, T. A.,Chen, L. Y.,Chen, B. M. The Electrochemical Society 2007 Electrochemical and solid-state letters Vol.10 No.9

Solidification and Evolution of β-NiAl Phase in a Re-Containing Single Crystal Superalloy

Y. M. Li,X. G. Wang,Z. H. Tan,Y. H. Yang,J. L. Liu,J. D. Liu,J. G. Li,Y. Z. Zhou,X. F. Sun 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.10

The β-NiAl phase, which may exacerbate the high-temperature mechanical properties of Ni-based superalloy, was observedin a designed Re-containing single crystal superalloy. The solidification mechanism of β-NiAl phase and its evolutionafter solution treatment as well as long-term aging at 1120 °C were systematically investigated. The β-NiAl phase wasconfirmed by the analyses of XRD and TEM in as-cast specimen. Combined the analyses of TEM, DSC, phase diagramsand chemical segregation behaviors obtained via EPMA, the solidification path in interdendritic region was determined asL → (β-NiAl + Cr) eutectic, L → β + δ, L + β → γ′, L → γ′. The β-NiAl phase could be diminished by solution treatment and/or long-term aging treatment. After the solution treatment at 1330 °C for 30 min, the β-NiAl phase split into small bulks andthe δ phase dissolved, contributing to the formation of the γ + γ′ structure and large blocky δ phase. During the long-termaging at the 1120 °C, the β-NiAl phase transformed into γ and γ′ phase. With aging time prolonging, the Cr-rich phase dissolved,which promoted the precipitation of TCP confirmed as μ phase with three morphologies.