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1Influence of Gd_2O_3 and Yb_2O_3 Co-doping on Phase Stability,Thermo-physical Properties and Sintering of 8YSZ显示文摘The role of multicomponent rare earth oxides in phase stability, thermophysical properties and sintering for ZrO2-based thermal barrier coatings (TBCs) materials is investigated. 8YSZ codoped with 3 mol% Gd2O3 and 3 mol% Yb2O3 (GYb-YSZ) powders are synthesized by solid state reaction for 24 h at various temperatures. As temperature increases, stabilizers are dissolved into zirconia matrix gradually. Synthesized at 1 500 °C, GYb-YSZ is basically composed of cubic phase. GYb-YSZ exhibits excellent phase stability and sinters lower than 8YSZ by nearly three times. The thermal conductivity of GYb-YSZ is much lower than that of 8YSZ, and the thermal expansion coefficient of GYb-YSZ is comparable to that of 8YSZ. The influence of Gd2O3 and Yb2O3 co-doping on phase stability, thermal conductivity and sintering of 8YSZ is discussed.ZHANG Yanli GUO Lei YANG Yongping GUO Hongbo ZHANG Hongju GONG Shengkai 2012Chinese Journal of Aeronautics2012,25,6:17
2Hot Corrosion Behavior of Double-ceramic-layer LaTi_2 Al_(9)O_(19)/YSZ Thermal Barrier Coatings显示文摘LaTi 2 Al 9 O 19 (LTA) exhibits promising potential as a new kind of thermal barrier coating (TBC) material, due to its excellent high-temperature capability and low thermal conductivity. In this paper, LTA/yttria stabilized zirconia (YSZ) TBCs are produced by atmospheric plasma spraying. Hot corrosion behavior and the related failure mechanism of the coating are investigated. Decomposition of LTA does not occur even after 1 458 hot corrosion cycles at 1 373 K, revealing good chemical stability in molten salt of Na 2 SO 4 and NaCl. However, the molten salt infiltrates to the bond coat, causing dissolving of the thermally grown oxide (TGO) in the molten salt and hot corrosion of the bond coat. As a result, cracking of the TBC occurs within the oxide layer. In conclusion, the ceramic materials LTA and YSZ reveal good chemical stability in molten salts of Na 2 SO 4 and NaCl, and the bond coat plays a significant role in providing protection for the component against hot corrosion in the LTA/YSZ TBCs. LTA exhibits very promising potential as a novel TBC material.XIE Xiaoyun GUO Hongbo GONG Shengkai XU Huibin 2012Chinese Journal of Aeronautics2012,25,1:9
3Effect of Sintering on Thermal Conductivity and Thermal Barrier Effects of Thermal Barrier Coatings显示文摘Thermal barrier coatings (TBCs) are mostly applied to hot components of advanced turbine engines to insulate the components from hot gas. The effect of sintering on thermal conductivity and thermal barrier effects of conventional plasma sprayed and nanostructured yttria stabilized zirconia (YSZ) thermal barrier coatings (TBCs) are investigated. Remarkable increase in thermal conductivity occurs to both typical coatings after heat treatment. The change of porosity is just the opposite. The grain size of the nanostructured zirconia coating increases more drastically with annealing time compared to that of the conventional plasma sprayed coating, which indicates that coating sintering makes more contributions to the thermal conductivity of the nanostructured coating than that of the conventional coating. Thermal barrier effect tests using temperature difference technique are performed on both coatings. The thermal barrier effects decrease with the increase of thermal conductivity after heat treatment and the decline seems more drastic in low thermal conductivity range. The decline in thermal barrier effects is about 80 °C for nanostructured coating after 100 h heat treatment, while the conventional coating reduces by less than 60 °C compared to the as-sprayed coating.WANG Kai PENG Hui GUO Hongbo GONG Shengkai 2012Chinese Journal of Aeronautics2012,25,5:7
4High-Temperature Metamorphism, Anataxis and Tectonic Evolution of a Mafic Granulite from the Eastern Himalayan Orogen显示文摘The Himalayan Orogen, resulting from the Tertiary collision of Indian and Asian continents, is a natural laboratory for studying metamorphism, partial melting and granite formation of collisional orogens. However, metamorphic and anatectic conditions and timescales of meta-mafic rocks in the Greater Himalayan Sequences(GHS) in the east-central Himalaya remain controversial. In this paper, we conduct a study of petrology and geochronology of mafic granulite from the Eastern Himalayan Syntaxis(EHS). The mafic granulite with abundant leucosome bands occurs as layers within felsic granulites and is well deformed. The granulite consists of garnet, plagioclase, amphibole and quartz with minor clinopyroxene, orthopyroxene, biotite, rutile, titanite and ilmenite. The garnet has growth compositional zoning and contains abundant mineral inclusions in its core. Peak metamorphic mineral assemblage of the granulite is garnet, amphibole, plagioclase, quartz, clinopyroxene and rutile, recording a high-pressure(HP) and high-temperature(HT) peak-metamorphism under conditions of 14–15.5 kbar and 780–790℃ in the presence of melt. The reconstructed clockwise P-T path is characterized by an early heating and burial prograde metamorphism, and late isothermal and cooling decompression retrogression. The granulite witnessed a long lasting HT metamorphism, partial melting and melt crystallization process which began at ca. 39 Ma and lasted to ca. 11 Ma. The present study shows that various high-grade rocks of the GHS in the EHS core experienced similar metamorphic conditions and P-T-t paths, indicating that they occurred as a coherent slab during the subduction and exhumation of Indian lithosphere. The significant melts generated during the prograde metamorphism of the GHS rocks not only contributed to the formation of the Himalayan leucogranite, but also resulted in the rheological weakening and ductile flow of the thickened lower crust of the Himalayan Orogen.Zeming Zhang Huixia Ding Xin Dong Zuolin Tian Dongyan Kang Hongchen Mu Shengkai Qin Yuanyuan Jiang Mengmei Li 2018Journal of Earth Science2018,29,5:7
5Degradation of EB-PVD thermal barrier coatings caused by CMAS depositsHui Peng Lu Wang Lei Guo Wenhui Miao Hongbo Guo Shengkai Gong 2012Progress in Natural Science:Materials International2012,22,5:7
6Suppressing the formation of SRZ in a Ni-based single crystal superalloy by RuNiAl diffusion barrierZhiming Bai Dongqing Li Hui Peng Juan Wang Hongbo Guo Shengkai Gong 2012Progress in Natural Science:Materials International2012,22,2:6
7Effects of Dy on Transient Oxidation Behavior of EB-PVD β-NiAl Coatings at Elevated Temperatures显示文摘-NiAl 是在温度要操作在上面的潜在的氧化抵抗的涂层材料 1 150 ? 潦 ? 浩牰癯湩 ? 桴 ? 潰楳楴湯湩 ? 捡畣慲祣椠 ? 祤慮業?ZHAO Xiaoyu GUO Hongbo GAO Yuzhi WANG Shixing GONG Shengkai 2011Chinese Journal of Aeronautics2011,24,3:6
8Effect of Mo content on microstructure and stress-rupture properties of a Ni-base single crystal superalloy显示文摘The additional 1.5 wt% Mo was added in a Ni-base single crystal(SC) alloy with the composition of Ni–6.5Al–8.0Mo–2.4Cr–6.2Ta–4.9Co–1.5Re–(0.01–0.05)Y(wt%) to study the effect of Mo content on the microstructure and stress-rupture properties. The creep and stress-rupture tests under the conditions of 850 °C/500 MPa and 1100 °C/130 MPa were conducted, and the microstructure of as-cast, heat treated and stress ruptured specimens were analyzed. It was found that the 1.5 wt% Mo addition enhanced the stress-rupture lives at both intermediate(850 °C) and high(1100 °C)temperatures. The microstructure analysis showed that adding 1.5 wt% Mo in the basic alloy affected the microstructure dramatically, i.e., the Mo-rich phases formed in the specimens of as-cast and stress-ruptured specimens. It is considered that the improvement of the stress-rupture lives is duo to the strengthening effect of Mo to both γ and γ'phases and the decrease of stacking fault energy, diffusion constant and dislocation spacing. The Mo-rich phases precipitated under condition of 1100 °C/130 MPa did not affect the creep and stress-rupture properties obviously in the present study.Yunfei Liang Shusuo Li Cheng Ai Yafang Han Shengkai Gong 2016Progress in Natural Science:Materials International2016,26,1:5
9Implementation of encoder and decoder for LDPC codes based on FPGA显示文摘This paper proposes a parallel cyclic shift structure of address decoder to realize a high-throughput encoding and decoding method for irregular-quasi-cyclic low-density parity-check(IR-QC-LDPC)codes,with a dual-diagonal parity structure.A normalized min-sum algorithm(NMSA)is employed for decoding.The whole verification of the encoding and decoding algorithm is simulated with Matlab,and the code rates of 5/6 and 2/3 are selected respectively for the initial bit error ratio as 6%and 1.04%.Based on the results of simulation,multi-code rates are compatible with different basis matrices.Then the simulated algorithms of encoder and decoder are migrated and implemented on the field programmable gate array(FPGA).The 183.36 Mbps throughput of encoder and the average 27.85 Mbps decoding throughput with the initial bit error ratio 6%are realized based on FPGA.CHENG Kun SHEN Qi LIAO Shengkai PENG Chengzhi 2019Journal of Systems Engineering and Electronics2019,30,4:4
10Impermeability of Y_3Al_5O_(12) ceramic against molten glassy calcium-magnesium-alumina-silicate显示文摘Degradation of thermal barrier coatings(TBCs) caused by calcium-magnesium-aluminasilica(CMAS) glassy penetration is becoming an urgent issue for TBCs industrial applications. In this work, yttrium aluminum garnet(Y_3Al_5O_(12), YAG) nano-powders were synthesized through a chemical co-precipitation route. The resistance of YAG ceramic to glassy CMAS infiltration at1250 °C was evaluated. YAG ceramic bulk sintered at 1700 °C for 10 h was comprised of a single garnet-type Y_3Al_5O_(12) phase. The molten CMAS glass was suppressed on the surface of the YAG ceramic at 1250 °C. A chemical reaction between YAG and the molten CMAS glass did not occur at 1250 °C for 24 h, suggesting that YAG could act as an impermeable material against glassy CMAS deposits in the TBC field.Zhaolu XUE Yue MA Shengkai GONG Hongbo GUO 2018Chinese Journal of Aeronautics2018,31,12:4
11Effect of thermal exposure on the stress-rupture life and microstructure of a low Re-containing single crystal alloy显示文摘In this paper, the stress-rupture tests of a low Re-containing single crystal alloy IC21 before and after thermal exposure at 1100 ℃for various periods of time were conducted under the test condition of 1100 ℃/137 MPa, and the microstructure of the tested specimens was characterized by SEM and TEM. The experimental results showed that the stress rupture life of this alloy was over 150 h after the standard heat treatment of1320 ℃, 10 h/AC t 870, 32 h/AC, however the stress rupture life decreased with the increase of exposure time due to the microstructure degradation. The TEM analysis revealed that the interface mismatch dislocation networks were well established. It was observed that these mismatch networks could form at 1100 ℃ even after thermal exposure for 1 h without the external stress, which is quite different from that in the traditional single crystal superalloys.Heng Zhang Yunfei Liang Yi Ru Shusuo Li Jian Zhou Shengkai Gong 2015Progress in Natural Science:Materials International2015,25,1:4
12Introduction to game theory显示文摘The basic ideas of game theory were originated from the problems of maximum and minimum given by J.Yon Neumann in 1928. Later, wars accelerated the study of game theory, there are many developments that contributed to the advancement of game theory, many problems of optimum appeared in economic development process. Scientists applied mathematic methods to studying game theory to make the theory more profound and perfect. The axiomatic structure of game theory was nearly complete in 1944. The path of the development of game theory started from finite to infinite, from two players to many players, from expressing gains with quantity to showing the ending of game theory with abstract result, and from certainty problems to random problems. Thus development of game theory is closely related to the economic development. In recent years, the research on the non-differentiability of Shapley value posed by Belgian Mertens is one of the advanced studies in game theory.ZHANG Shengkai & ZHANG YadongDalian Institute of Light Industrial Technology, Dalian 116034, China Correspondence should be addressed to Zhang Shengkai (e-mail: ZSK@ 163.net.cn) 2003Chinese Science Bulletin2003,48,9:4
13Effects of Jiazhu decoction in combination with cyclophosphamide on breast cancer in mice显示文摘OBJECTIVE: To investigate the therapeutic effects of Jiazhu decoction (JZD) in combination with cyclophosphamide (CTX) on the growth of breast cancer in mice and to explore the possible molecular mechanisms of action. METHODS: BALB/c mice were randomly divided into four groups of 10 (untreated model group, JZD group, CTX group, and JZD + CTX group) and subcutaneously injected with 4T1 mouse breast cancer cells. Tumors were allowed to establish for ~7 d before initiation of treatment with CTX (100 mg/kg every week by intraperitoneal injection) and/or JZD (0.015 mL of 1.65 g/mL crude drug, administered daily by gavage). The model group received equivalent volumes of vehicle on the same schedules. Tumor volumes were measured every 3 d. Mice were sacrificed after 3 weeks of treatment, and tumors were excised and subjected to RT-qPCR and western blot analysis to evaluate expression of the Wnt/β-catenin signaling pathway components β-catenin, c-Myc, and cyclin D1 at the mRNA and protein levels. RESULTS: The mean tumor volume was smaller and the growth rate was slower in the CTX and JZD + CTX groups compared with the model group (P < 0.05), and in the JZD + CTX group compared with the CTX and JZD groups (P < 0.05). Tumor growth was inhibited by 35.4% and 48.1% by CTX and JZD + CTX treatment, respectively (P < 0.001). The expression of β-catenin, c-Myc, and cyclin D1 mRNA and protein in tumors was significantly lower in mice treated with JZD or JZD + CTX compared with the untreated mice (P < 0.05), and was significantly lower in mice treated with JZD + CTX compared with either JZD or CTX alone (P < 0.05). CONCLUSION: JZD inhibited the growth of mouse breast cancer cells in vivo, possibly by reducing the expression of β-catenin, c-Myc, and cyclin D1. Combination therapy with JZD plus CTX had a more potent inhibitory effect on breast cancer growth compared with either agent alone.Guan Huiting Xie Su Liu Shangyi Xie Qing Hou Shengkai Liu Huarong Zhang Yunjie Hu Yaqing Zhang Chenyu 2019Journal of Traditional Chinese Medicine2019,39,5:4
14Cyclic Oxidation Behavior of an EB-PVD CoCrAlY Coating Influenced by Substrate/coating Interdiffusion显示文摘To reveal the influence of substrate/coating interdiffusion on the cyclic oxidation property of a metallic coating, cyclic oxidation behavior of an EB-PVD CoCrAlY coating on directionally solidified Ni-based superalloy DZ125 at 1 050 oC is investigated. The 40 μm thick CoCrAlY coating has a cyclic oxidation life of around 160 h, and the oxidation constant is 1.915× 10.7 mg4·cm.8·s.1. However, severe spallation of the oxides containing Co, Cr, Ni, Ta and Ti occurs with longer cyclic oxidation. The degradation in oxidation resistance for the coating is related to the depletion of Al due to the oxide spallation and interdiffusion. Severe interdiffusion between the coating and underlying substrate occurs at 1 050 oC. The composition of the substrate has an important effect on the thermal cycling lifetime of the coating. The influencing mechanism is discussed.LIANG Tianquan GUO Hongbo PENG Hui GONG Shengkai 2012Chinese Journal of Aeronautics2012,25,5:3
15Phase stability and thermal conductivity of ytterbia and yttria co-doped zirconia显示文摘Rare earth oxides doping has been extensively investigated as one of the effective methods to lower thermal conductivity of 4.55 mol% Y2O3stabilized ZrO2(YSZ) thermal barrier coatings(TBCs).In the present work,5–6 mol% Yb2O3and Y2O3co-doped ZrO2ceramics were synthesized by solid reaction sintering at 1600 1C.The phase stability of the samples after heat treatment at 1500 1C was investigated.Yb2O3and Y2O3co-doped zirconia,especially when Yb2O3/Y2O3≥1,contained less monoclinic phase than single Yb2O3or Y2O3phase doped zirconia,indicating that co-doped zirconia was more stable at high temperature than YSZ.The thermal conductivity of the 3 mol% Yb2O3+3 mol% Y2O3co-doped ZrO2was 1.8 W m 1K 1at 1000 1C,which was more than 20% lower than that of YSZ.Leilei Sun Hongbo Guo Hui Peng Shengkai Gong Huibin Xu 2013Progress in Natural Science:Materials International2013,23,4:3
16Influence of Mo and Ta additions on solidification behavior of Ni_3Al single crystal alloys显示文摘Ni3Al(Ni75Al25) and Ni3Al–2Mo/Ta(Ni73.5Al24.5Mo/Ta2) single crystals were prepared by the Bridgman method under high temperature gradient(~170℃/cm) at the withdrawal rates of 5 and 20 μm/s. The experimental results showed that the addition of Mo decreased the liquidus and solidus temperatures, and the addition of Ta increased the liquidus and solidus temperatures. Meanwhile, both Mo and Ta additions were found to increase the solidi fi cation range of experimental alloy. It has been found that for solidi fi cation of stoichiometric Ni3Al at low withdrawal rate(5 μm/s), β/γ’eutectic first solidi fied from liquid(L→β+γ’) and then β phase completely transformed into pure γ’(β→γ’) after the completion of solidi fi cation. However, at high withdrawal rate of 20 μm/s, the remaining β phase was found in the as-cast microstructure of Alloy Ni3Al. Different from stoichiometric Ni3Al, the solidi fi cation sequence of Alloy Ni3Al–2Mo was identi fi ed as L→β+γ’+Mo-rich phase(ternary eutectic reaction). In addition, the addition of Ta led to the formation of primary γ’phase and then subsequent intercellular/interdendritic β/γ’eutectic microstructure. Based on above study, a new Ta and Mo containing Ni3Al based single crystal alloy with superior tensile strength at ultra-high temperature(>1100℃) was designed.Cheng Ai Shusuo Li Yunfei Liang Shengkai Gong 2015Progress in Natural Science:Materials International2015,25,4:2
17A ZnO thin-film driven microcantilever for nanoscale actuation and sensing显示文摘Zinc oxide(ZnO)thin film as a piezoelectric material for microelectromechanical system(MEMS)actuators and sensors was evaluated.ZnO thin films were deposited using radio frequency(RF)magnetron sputtering.Process parameters such as gas ratio,working pressure,and RF power were optimized for crystalline structure.The ZnO thin films were characterized by X-ray diffraction(XRD)and scanning electron microscopy(SEM).Good quality of ZnO thin films was further confirmed by a high transverse piezoelectric coefficient d31.A microcantilever was then designed,fabricated,and characterized.Design formulas of resonant frequency,actuation,and sensing sensitivities were derived.The resonant frequency was determined by an impedance analyzer.Tip deflection on nanometer level was demonstrated with the cantilever used as an actuator.The actuation sensitivity was found to be 12.2 nm/V.As a sensor,the cantilever was calibrated against a reference accelerometer.The sensing sensitivity was characterized to be 46 mV/g.The characterization results were compared with design specifications.The differences were caused mainly by thickness control in etching.This study showed that ZnO is a promising piezoelectric material for MEMS actuators and sensors in terms of excellent process compatibility and good piezoelectric performance.Yanhui Yuan Kun Shyong Chow Hejun Du Peihong Wang Mingsheng Zhang Shengkai Yu k Bo Liu 2013International Journal of Smart and Nano Materials2013,4,2:2
18Arctic sea ice thickness variations from CryoSat-2 satellite altimetry data显示文摘Arctic sea ice plays an important role in Earth's climate and environmental system.Sea ice thickness is one of the most important sea ice parameters.Accurately obtaining the sea ice thickness and its changes has great significance to Arctic and global change research.Satellite altimeters can be used to derive long-term and large-scale changes in sea ice thickness.The leads detection is vital in sea ice thickness estimation by using satellite altimetry.Different leads detection methods are compared with remote sensing images,and results show that the detection method that uses waveform parameters can obtain improved results.The model for the conversion of freeboard to thickness is optimized by considering the incomplete penetration of snow for radar altimeters.We derive the estimates of the Arctic sea ice thickness for November 2010 to December 2019 by using the CryoSat-2 altimetry data.The sea ice thickness from the IceBridge and draft data from the upward-looking sonar are used to validate our thickness results.Validations show that the accuracy of our thickness estimates is within 0.2 m.Variations in the Arctic sea ice thickness are analyzed using the PIOMAS model and air and sea surface temperatures.A sharp increase in sea ice thickness is found in 2014.Feng XIAO Shengkai ZHANG Jiaxing LI Tong GENG Yue XUAN Fei LI 2021Science China Earth Sciences2021,64,7:2
19Versatile metal graphitic nanocapsules for SERS bioanalysis显示文摘The novel graphitic nanomaterial of metal graphitic nanocapsules(MGNs) with superior stability, unique optical properties and biocompatibility possess great potential in biomedical and bioanalytical applications. The graphitic shell can quench the background fluorescence interference from external environments via a fluorescence resonance energy transfer(FRET) process and even avoid unnecessary reactions catalyzed by inner metal core. The graphitic shell with several characteristic Raman bands itself can act as Raman signal probe or internal standard(IS), especially the 2D-band within the cellular Raman-silent region helps to reduce the interference signals from external conditions. The present context attempts to give a comprehensive overview about the preparation and unique properties of MGNs as well as their applications in SERS biodetection and bioimaging.Shengkai Li Jiamei Xu Shen Wang Xin Xia Long Chen Zhuo Chen 2019Chinese Chemical Letters2019,30,9:2
20Versatile Graphene-Isolated AuAg-Nanocrystal for Multiphase Analysis and Multimodal Cellular Raman Imaging显示文摘Surface-enhanced Raman spectroscopy(SERS)-based bioanalytical technique involves the interaction of SERS-active substrate with complex environment,which has aroused intensive research interests.Compared to the commonly used Au SERS substrates,Ag nanocrystals have larger optical absorption cross section and acceptable price,but they possess poor oxidation resistance and potential biotoxicity,and the occurrence of unnecessary chemical reactions is inevitable due to the direct contact with probe molecules.Herein,we report a graphene-isolated AuAg nanocrystal(GIAAN)with the SERS-active AuAg core confined in a nanospace of few-layer graphene shell,which possesses unique Raman peaks,high SERS activity,excellent stability,superior fluorescence quenching performance and good biocompatibility.Based on the limited solubility of GIAAN in water and organic solvents,it is able to spontaneously generate interfacial self-assembled GIAAN(ISA-GIAAN)film at immiscible two-phase interfaces without any inducer,and multiphase Raman analysis of both water-and lipid-soluble drug model molecules is further achieved.Moreover,the GIAAN is further non-covalently functionalized with polyoxyethylenestearyl ether(C18-PEG)to acquire GIAAN@PEG with good water-solubility for SERS quantitative analysis in homogeneous system and multimodal Raman imaging of MCF-7 cells.We expect the versatile GIAAN holds great potential to monitor drug metabolism and guide intended drug delivery in clinic trials.Shengkai Li Zhaotian Zhu Xinqi Cai Minghui Song Shen Wang Qing Hao Long Chen Zhuo Chen 2021Chinese Journal of Chemistry2021,39,6:2
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