ISSN 0253-2778

CN 34-1054/N

2015 Vol. 45, No. 11

Display Method:
Random weighting method for smoothed binary response model
YUAN Min, WU Xiaoyan
2015, 45(11): 881-892. doi: 10.3969/j.issn.0253-2778.2015.11.001
The smoothed score estimating method has the nice properties of n-consistency and asymptotic normality under some regular assumptions. However, the asymptotic variance involves quantities related to the unknown error distribution which is hard to be accurately estimated. A random weighting method for estimating the asymptotic variance of the maximum smoothed score estimators was proposed. The random weighting estimator is shown to be consistent and asymptotically normal. Statistical inference is thus possible with the variance estimates.
The asymptotic solution to singularly perturbed boundary value problems for nonlinear nonlocal elliptic equations of higher order with two parameters
OUYANG Cheng, SHI Lanfang, MO Jiaqi
2015, 45(11): 893-898. doi: 10.3969/j.issn.0253-2778.2015.11.002
The singularly perturbed boundary value problem for a class of nonlinear nonlocal elliptic equation of higher order was considered. Under suitable conditions, the outer solution of the original problem was obtained. Then, applying the multiple scales variable and the method of component expansion, the first and second boundary layer corrective terms were constructed and the formal asymptotic expansion was obtained. Finally, applying the theory of differential inequalities the asymptotic expansion of a solution for the boundary value problem with two parameters was studied. Some relational inequalities were educed. And the existence of the solution for the original problem and the uniformly valid asymptotic estimation were discussed.
Impulsive stochastic differential equations of Sobolev-type
YUE Chaohui, WANG Hongxi
2015, 45(11): 899-905. doi: 10.3969/j.issn.0253-2778.2015.11.003
A class of impulsive stochastic differential equations of Sobolev-type was studied. The existence and uniqueness of the mild solution with the coefficients satisfying some generalized Lipschitz conditions was proved by means of the successive approximation. Moreover, the continuous dependence of the solutions on the initial values was given.
The continuity condition for harmonic Bézier surfaces
NI Qian, WANG Xuhui
2015, 45(11): 906-910. doi: 10.3969/j.issn.0253-2778.2015.11.004
The relationships between control points for two bi-degree (n,n) harmonic Bézier surface patches were studied, when these two surface patches are C continuous at the common boundary. The result shows that when the two harmonic Bézier surfaces are Cr continuous, the two harmonic Bézier surface patches are from the same piece of surface.
Conceptual design and analysis of the shim-rod assembly for lead-bismuth eutectic (LBE) cooled reactor
ZHANG Kanglong, SONG Yong, GUO Haomin, WANG Jianye
2015, 45(11): 911-916. doi: 10.3969/j.issn.0253-2778.2015.11.005
A structure scheme of shim-rod assembly including absorber bundle, gripper, ballast, inner wrapper, wrapper etc. was proposed to solve the problem caused by the high density and high buoyancy coolant in the lead-bismuth cooled reactor. The mechanical analysis of the inner wrapper and the upper gripper was carried out based on the computation performed by finite element method. The stress changing tendency of the inner wrapper was analyzed and the structure of the upper gripper was verified, which indicates the feasibility of the shim-rod assembly design, providing a reference for other internals facing similar environments in LBE cooled reactors.
Large eddy simulation for the turbulent heat transfer of liquid metal in an annulus
LYU Yijun, PENG Yongsheng, GE Zhihao, ZHAO Pinghui
2015, 45(11): 917-922. doi: 10.3969/j.issn.0253-2778.2015.11.006
Large eddy simulations (LES) for turbulent heat transfer at different molecular Prandtl numbers (Pr=001, 0026, 02, 04, 071) at Re=8 900 in an annulus were performed. Several statistics quantities such as time-mean temperature, temperature fluctuation, turbulent heat flux and turbulent Prandtl number were presented and analyzed. The characteristics of turbulent heat transfer of liquid metal (Pr=001,0026) were compared with those of the traditional fluids (Pr=04,071). The results show that the molecular conduction is the dominant heat transfer mechanism for the liquid metal. The linear law region extends larger while the logarithmic law region becomes shorter and even disappears compared to traditional fluids. With the decrease of Pr, the temperature fluctuation and turbulent heat flux become smaller. Beside, the turbulent Prandtl number of liquid metal is bigger than that of traditional fluids and is very sensitive to its molecular Prandtl number Pr.
One-step synthesized Pd concave nanostructures for HCOOH electrooxidation
RAO Zhoulv, LONG Ran, XIONG Yujie
2015, 45(11): 923-927. doi: 10.3969/j.issn.0253-2778.2015.11.007
Based on our previous work, Pd concave nanostructures with well-controlled sizes and shapes were obtained by the addition of Ru3+ during a synthetic process. The electrocatalytic oxidation of HCOOH by the four samples obtained from this synthesis was further examined. The experimental results show that by increasing the concentration of added Ru3+, the resulting Pd nanocrystals exhibit gradually improved activities in the electrocatalytic oxidation of HCOOH, which reaches the current density as high as 3507 A/g. Given the convenient synthetic method and excellent electrocatalytic performance, this series of Pd concave nanostructures could be promising candidates for commercial use.
Polarization-agile antenna based on the power-divider-phase-shifter
XU Hong, ZHU Qi
2015, 45(11): 928-933. doi: 10.3969/j.issn.0253-2778.2015.11.008
A new structure for the polarization-agile antenna was presented based on the power-divider-phase-shifter. By using the power-divider-phase-shifter, two equal-amplitude signals with +90°/-90°switched phase shift at two output ports can be achieved, which can be used to realize a dual-circular polarized polarization-agile antenna. Compared with traditional polarization-agile antenna which use an independent power divider and phase shifter, the new polarization-agile antenna has the advantage of high polarization purity and simple control circuits, etc.
Particle filter tracking based on visual saliency feature
WU Shidong, BAO Hua, ZHANG Chenbin, CHEN Zonghai
2015, 45(11): 934-942. doi: 10.3969/j.issn.0253-2778.2015.11.009
To address the problem of moving object tracking in complicated scenes, a particle filter tracking algorithm based on visual saliency feature was presented. The algorithm detects the object in the image with the saliency detection algorithm to get saliency maps. Target states are predicted using the second-order autoregressve model, and the final saliency map is obtained with the center-strengthening and edge-weakening mechanism. The saliency feature is extracted according to the phenomenon that in the saliency map pixel value is greater when the pixel is in the target area, and is then fused with the color feature adaptively to complete tracking. Experimental results show that the algorithm can effectively deal with the situation when illumination and appearance change.
Improved interference cancellation method over Y channel
TIAN Xinji, LI Xiaojing
2015, 45(11): 943-948. doi: 10.3969/j.issn.0253-2778.2015.11.010
An interference cancellation method based on space-time code and codeword space alignment was proposed for MIMO Y interference channel, which consists of three users and a relay. An alamouti-based space-time coded is designed for each user. Codewords after space alignment pre-coding are sent to the relay in two steps during the multi access stage. The symbols estimated at the relay are encoded and are sent to three users in two steps during the broadcast stage. Both the multi access stage and the broadcast stage occupy four time slots, in which 24 independent modulated symbols are transmitted. Compared with the existing scheme for the same scene, the proposed scheme greatly reduces the amount of feedback, while keeping the same transmission rate. Simulation results demonstrate that the reliability of the proposed scheme is very close to that of the existing scheme for the same scene.
Study on the heights of the highest mountains of Mars and the Earth and their difference
CHEN Chuxin, CHANG Zhen
2015, 45(11): 949-952. doi: 10.3969/j.issn.0253-2778.2015.11.011
The radius of Mars is only half of that of Earth, while the height of Mount Olympus, the highest mountain on Mars, is more than twice of that of Everest on Earth. There are still some peaks on Mars which are much higher than Everest. To explain the appearance of mountains or protrusions disproportional to the scale of the planet, a stress model of a mountain was set up. It was found that the main factor that affects the highest mountains height is gravitational acceleration. The smaller the planet, the smaller its surface gravitational acceleration, and the more prominent the protrusions on its surface. The depth of the deepest trench on Earth was also estimated using the same method; the result is close to reality.
Effect evaluation of Zn bio-fortification on garlic
PAN Fei, WANG Zhangmin, LIU Qi, YUAN Linxi, YIN Xuebin
2015, 45(11): 953-959. doi: 10.3969/j.issn.0253-2778.2015.11.012
A field experiment was conducted to evaluate the effect of zinc (Zn) fertilization on Zn accumulation in garlic plants. The experiment was designed as five zinc treatment groups and one control, and Zn was added as base fertilizer. The results showed that the Zn mass fractions in garlic leaves, young garlic shoots and the bulbs were significantly increased up to 935, 718 and 964 mg/kg (dry weight) respectively. The Zn forms in different edible garlic organs all changed after the addition of Zn fertilizers. Furthermore, the proportions of free Zn ions were improved in garlic leaves, young garlic shoots and bulbs with the increase of Zn levels, while the proportions of water-extractable Zn and residual Zn decreased. However, the proportion of salt- and alkali-extractable Zn increased in garlic leaves and young garlic shoots, but decreased in the bulbs. The in vitro simulation of gastrointestinal digestion showed that the Zn dissolution rate in Zn-fortified bulbs increased by 68% compared to the control. When mixing together with rice, the Zn dissolution rate of garlic bulbs increased by 2.6 times, which indicates that the nutritional quality of Zn improved significantly via bio-fortification.
Vertical distribution characteristics of organochlorine pesticides in the sediment core from the Yellow River Estuary
DA Chunnian, LIU guijian, LlU Houqi, WU Yang, YUAN Zijiao
2015, 45(11): 960-966. doi: 10.3969/j.issn.0253-2778.2015.11.013
GC-MS internal standard and 210Pb isotopic dating methods were used to discuss the content and vertical distribution characteristics of organochlorine pesticides in the sediment core from the Yellow River Estuary.The historical records of the pollution of organicchlorine pesticides were established to provide basic data for the protection of the ecological system of the Yellow River Estuary. The results show that the mass froutions of ΣDDTs and ΣHCHs in the sediment core are 0.001~14.85 ng·g-1 and 0.04~1.07 ng·g-1, respectively. Contents had been increasing since 1925, peaking in 1961, and then decreased gradually.The first peak of the content of HCHs in the sediment core came in the early 1960s. This peak is associated with the history of HCHs in 1960s in China. The second peak of the content of HCHs in the sediment core occurred in 1988, and is associated with the history of lindane in 1988 in China. The content of DDTs increased slightly from 1925 to 1950s, and sharply in the early 1960s, and the content of DDTs in the surface of the sedimentary column decreased significantly after several fluctuations. The first peak of the DDTs content in the sediment core occurred in 1964, and the second peak of DDTs in the sediment core is in 1990. The amount of DDTs used over time affected the residue in the sediment core. Compared with the other estuarine and coastal regions in Chinese rivers, the vertical average content of HCHs in the sediments of the Yellow River Estuary is close to that of Taihu, which is slightly lower than that of the Pearl River Estuary, but higher than that of the Quanzhou Bay and the Gulf of Sanya. The vertical average content of DDTs is lower than that of the Pearl River Estuary, Quanzhou, Dayawan Bay and Sanya Bay.