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71.
DONG Bin GAO YaChen XU XueSong SUN Min LI Lei 《科学通报(英文版)》2007,52(19):2626-2629
The Er3 doped Al2O3 powders were prepared by the sol-gel method using the aluminium isopropoxide [Al(OC3H7)3]-derived Al2O3 sols with addition of the erbium nitrate [Er(NO3)3.5H2O]. The different phase structure, including three crystalline types of (Al,Er)2O3 phases, γ, θ, α, and two Er-Al-O phases, ErAlO3 and Al10Er6O24, was obtained with the 1 mol% Er3 doped Al2O3 powders at the different sintering temperatures of 600―1200℃. The green and red up-conversion emissions centered at about 523, 545 and 660 nm, corresponding respectively to the 2H11/2, 4S3/2→4I15/2 and 4F9/2→4I15/2 transitions of Er3 , were detected by a 978 nm semiconductor laser diodes excitation. The phase structure and OH content had evident influence on the up-conversion emissions intensity. The maximum intensities of both the green and red emissions were obtained respectively for the Er3 doped Al2O3 powders sintered at 1200 ℃, which was composed mainly of α-(Al,Er)2O3, less of ErAlO3 and Al10Er6O24 phases, and with the least OH content. The two-photon absorption up-conversion process was involved in the green and red up-conversion emissions of the Er3 doped Al2O3 powders. 相似文献
72.
The behavior of microwave attenuation in BaTiO3 electrorheological fluids is studied when considering microwave propagation in the directions perpendicular and parallel to the particle chains, respectively. In the former case, the microwave attenuation increases with field strength when the particle concentration is low, and the increase of the particle concentration can also increase the microwave attenuation. However, when the particle concentration exceeds a critical value, the attenuation will first increase then decrease with field strength. At the same time, the higher the field strength, the greater the change of microwave attenuation. Moreover, there is a saturation field strength. When the field strength is lower than the saturated one, the change of microwave attenuation is fast. On the other hand, in the case of microwave propagation parallel to the particle chains, the microwave attenuation increases with the field strength monotonously. In addition, the variation of microwave attenuation with the field strength shows relaxation effect. The adjustable character of microwave attenuation in BaTiO3 ER fluids can be attributed to the dielectric changes resulting from the field-induced-structural transformation and the polarization of BaTiO3. 相似文献
73.
CHENG Kai ZHAO Yijun XU Min YIN Jun XIONG Qin ZHOU Jinchen WANG Yuzhen ZHANG Wei WANG Jinwang LIU Zhaoyin WANG Furong 《自然科学进展(英文版)》2002,12(1):30-35
The results of ecological investigation of Microcystis blooms and their toxicity in a eutrophic park pond ( where the annual average of total nitrogen and total phosphorus was 6.1 mg'L-1 and 1. 79 mg'L-1. respectively) are presented. The blooms were mainly contributed by M. aeruginosa occurring in the period from May to October when water temperature ranged from 16 to 33 °C . Three remarkable growth peaks of Microcystis during the period were observed with chlorophyll a level of 0. 73 mg*L-1. 44 mg*L-1. and 1. 30 mg'L-1. respectively. The blooms were independent of phosphorus, but highly dependent on ammonium. A level of ammonium of 9. 5 mg'L-1 could trigger the outbreak of the bloom, while that below 0. 89 mg'L-1 could inhibit its formation. In other words, ammonium in higher concentrations could promote blooming, while that in lower concentrations could be inhibitory. Microcystis toxicity tended to increase with the blooming process, but the toxic peaks lagged behind their corresponding growth peaks. 相似文献
74.
Analysis of regulatory architectures in BST 总被引:2,自引:0,他引:2
Based on the data envelopment analysis (DEA) theory, the optimal pathway of metabolic reaction networks in biochemical systems is studied. After calculating the mixed-integer linear programming (MILP) model given by Bailey et al. twice, the decision making units (DMU) and the prediction model of DEA are constructed, where the inputs are levels of manipulated parameters (enzyme) and outputs are concentrations of metabolites. When the metabolic networks are reconstructed, the data are obtained by calculating MILP framework twice and the optimal levels of the manipulated parameter at different regular loops are predicted, thus simplifying the calculations of Bailey's. 相似文献
75.
Effect of different deformation and annealing procedures on non-magnetic textured Cu<Subscript>60</Subscript>Ni<Subscript>40</Subscript> alloy substrates 下载免费PDF全文
Jin Cui Hong-li Suo Jin-hua Wang Jean-Claude Grivel Lin Ma Chun-yan Li Yao-tang Ji Shaheen Kausar Min Liu Yi Wang 《矿物冶金与材料学报》2018,25(8):930-936
In this work, a series of specimens was prepared by the casting method. Sharp cube-textured substrates were processed by heavy cold rolling and recrystallization annealing (i.e., the rolling-assisted biaxially textured substrates (RABiTS) method). Both the rolling and the recrystallization texture in the alloy tapes were investigated by X-ray diffraction and electron back-scatter diffraction, respectively. The results showed that a strong copper-type deformation texture was obtained in the heavy cold-rolled substrate. In addition, the recrystallization annealing process was found to be very important for the texture transition in the Cu–Ni alloy substrates. The cube texture content in the Cu60Ni40 alloy substrates reached 99.7% (≤10°) after optimization of the cold-rolling procedure and the recrystallizing heat-treatment process, whereas the content of low-angle grain boundaries (from 2° to 10° misorientation) in the substrate reached 95.1%. 相似文献
76.
Yu Lou Zhongzheng Yao Shu Fu Sinan Liu Xindong Zhu Wen Huang Min Dong Jianrong Zeng He Lin He Zhu Si Lan 《自然科学进展(英文版)》2023,33(2):244-249
Metallic glass nanoparticles hold great promise as nonenzymatic glucose sensors due to their rich low-coordinated active sites and high biocompatibility. However,their non-periodic atomic structure and unclear structure-property relationship pose significant challenges for realizing and optimizing their sensing performance. In this work, Pd–Ni–P metallic glass nanoparticles with variable compositions were successfully prepared as nonenzymatic glucose sensors via a laser-evaporated inertgas conde... 相似文献
77.
Large-scale genome-wide association studies in East Asians identify new genetic loci influencing metabolic traits 总被引:1,自引:0,他引:1
Kim YJ Go MJ Hu C Hong CB Kim YK Lee JY Hwang JY Oh JH Kim DJ Kim NH Kim S Hong EJ Kim JH Min H Kim Y Zhang R Jia W Okada Y Takahashi A Kubo M Tanaka T Kamatani N Matsuda K;MAGIC consortium Park T Oh B Kimm K Kang D Shin C Cho NH Kim HL Han BG Lee JY Cho YS 《Nature genetics》2011,43(10):990-995
To identify the genetic bases for nine metabolic traits, we conducted a meta-analysis combining Korean genome-wide association results from the KARE project (n = 8,842) and the HEXA shared control study (n = 3,703). We verified the associations of the loci selected from the discovery meta-analysis in the replication stage (30,395 individuals from the BioBank Japan genome-wide association study and individuals comprising the Health2 and Shanghai Jiao Tong University Diabetes cohorts). We identified ten genome-wide significant signals newly associated with traits from an overall meta-analysis. The most compelling associations involved 12q24.11 (near MYL2) and 12q24.13 (in C12orf51) for high-density lipoprotein cholesterol, 2p21 (near SIX2-SIX3) for fasting plasma glucose, 19q13.33 (in RPS11) and 6q22.33 (in RSPO3) for renal traits, and 12q24.11 (near MYL2), 12q24.13 (in C12orf51 and near OAS1), 4q31.22 (in ZNF827) and 7q11.23 (near TBL2-BCL7B) for hepatic traits. These findings highlight previously unknown biological pathways for metabolic traits investigated in this study. 相似文献
78.
Lequan Min 《矿物冶金与材料学报》2000,7(2):139-146
The theorems for testing the local in one-port cellular neural/nonlinear network (CNN) cells with four local state variables are presented. Using the theorems computes the bifurcation diagrams of the cardiac Purkinje fiber (CPE) equations Which describe the long-lasting action and pace-maker potentials of the Purkinje fiber of the heart. The computer simulation shows that periodic trajectories or convergent trajectories of the CPF Equations can be foun if the cormsponing cell Parameters are located in a positive domain but nearby edge of chaos. In particular a heart with approximate normal frequency of heartbeat but non-normal electrocardiogram may suddenly stop by slightly perturbing the parameters of the corresponding CPF Equations when the Paramders are located nearby the edge of chaos in the bifurcation diagrams. This research seems to interpret reasonably the phenomena that patients with cardiac diseases might suddenly die without warning. 相似文献
79.
Analytical Criteria for Local Activity of CNN with Two-port and Application to Biochemical Model 下载免费PDF全文
The analytic criteria are presented for the local activity theory in two-port Cellular Neural Network (CNN) cells with three local state variables, and the application to a Biochemical Model CNN (BMCNN) is given for coupling in series of two enzymes whose prototype was studied by Decroly and Goldbeter. The bifurcation diagrams of the BMCNN's show that there does not exist a locally passive domain, and the computer simulation exhibited that convergent patterns, oscillatory patterns or chaotic patterns may emerge if the selected cell parameters are located in locally active unstable domains but nearby the edge of chaos domain. In particular, the coexistence of multiple oscillations was observed in the corresponding triple cell couples of the BMCNN's with the same initial conditions. 相似文献
80.
A new cellular neural network (CNN) with nonlinear templates is presented for extracting convex corners of objects in gray-scale images. Application examples showed that the new CNN can even detect convex corner characteristics of objects in im-ages with Gaussian noise. 相似文献