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The optimal investment strategy for defined-contribution occupational pension scheme
- YE Yan-Cheng, GAO Sui-Xiang
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2007, 24 (2):
149-153.
DOI: 10.7523/j.issn.2095-6134.2007.2.002
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Abstract (
1430 )
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This paper applies the theory of stochastic optimal control to deal with the optimal investment strategy problem for defined-contribution occupational pension scheme, sets up the optimal investment models under the minimum payment loss of the occupational pension fund in the deterministic and stochastic contribution cases separately, solves the HJB equations to obtain the explicit form solutions of the optimal investment decision and payment polices, and then uses Monte Carlo simulation for the optimal strategy in the deterministic contribution case.
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Solute redistribution during the Bridgman growth of compound crystal
- SHI Ke-Feng, LU Wen-Qiang
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2007, 24 (2):
161-166.
DOI: 10.7523/j.issn.2095-6134.2007.2.004
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Abstract (
1090 )
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Abstract: A numerical study is presented of the Bridgman crystal growth process of HgCdTe. Numerical results are reported for the effect of the pull rate and initial concentration on the solutal boundary layer near the interface. The results show that the solute diffusion will be restrained and the boundary layer becomes thin as the pull rate increases. Moreover, the variety of initial concentration lead to the change of segregate coefficient, which can affects the quantity of solute segregated during growth process, so that affect the solute diffusion. As a result, the solutal boundary layer is attenuated with the increase of initial concentration and this change is obvious when initial concentration is large.
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The neutron skin thickness and the equation of state for asymmetric nuclear matter
- LIU Ming, LI Zhu-Xia
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2007, 24 (2):
167-173.
DOI: 10.7523/j.issn.2095-6134.2007.2.005
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Abstract (
1224 )
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Based on the Skyrme energy density functional and the Thomas-Fermi expressions of the kinetic energy density, we use the restricted density variational method to calculate the neutron skin thickness for 208Pb, 112~124Sn, 48Ca, 96Zr, 18O with 47 Skyrme interactions available up to now. Comparing our calculated results with the experiment data, we explore the relations between the neutron skin thickness and the symmetry energy term of the equation of state(EOS) of nuclear matter. We find that the neutron skin thickness is sensitive to the nucleon-nucleon interaction and increases with the stiffness of the symmetry energy. Our study indicates that the model independent neutron skin thickness data are especially important for providing accurate information of the density dependence of the symmetry energy of nuclear matter. By calculating the neutron skin thickness of nuclei in the range of Z = 8 ~ 120, A = 5Z/3 ~ 3Z ,we find a linear relation between the neutron skin thickness and the isospin asymmetry degree δ: , which is in agreement with the result extracted from the measurements by antiproton annihilation method i.e.: . Using the data from antiproton annihilation method, we get the ranges of the slope , curvature of the symmetry energy near the saturated density (L, Ksym )and the symmetry energy coefficient as : L = 20 ~ 100MeV，Ksym =-256 ~ 70MeV, as = 30 ~ 35MeV. The Skyrme parameters SLy0-SLy10，SkM*，SkP，SLy230a，SkMP，SKT1-3，SkI3，MSk1-2，SII are in the above ranges.
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Study of thermal analysis technology of sulfonated wheat--strew soda lignin
- LIANG Wen-Xue, QIU Xue-Qing, OUYANG Xin-Ping, YANG Dong-Jie
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2007, 24 (2):
174-178.
DOI: 10.7523/j.issn.2095-6134.2007.2.006
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Abstract (
1441 )
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The thermal decomposition process of sulfonated wheat- strew soda lignin at the none-oxygen state was studied, using TG-IR and Non-isothermal Differential Scanning Calorimetry (DSC). The Kissinger and Ozawa equation kinetic parameters of the thermal decomposition were obtained. The apparent activation energy Ea, and pre-exponential factor, lnA, are 118.3 kJ•mol-1, 121.46 kJ•mol-1; 20.40min-1, 15.92min-1; respectively. The reaction order of the process is 1.8 by using Kissinger method.
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Heuristic method approach to the computational stability analysis of finite-dfference equations
- XIAO Cun-Ying, HU Xiong
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2007, 24 (2):
179-185.
DOI: 10.7523/j.issn.2095-6134.2007.2.007
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Abstract (
1322 )
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Some representative examples are adopted in this paper to discuss the differences between the stability conditions deduced from the original partial differential equations and that obtained from the expansion equations. It shows that for some difference equations, we’d better adopt the expansion equations in the process of the heuristic method being applied to these difference equations. In another part, apagoge is used in this paper to tell us that not all the stability conditions deduced by the heuristic method are the necessary computational stability conditions, which should be pay attention to in their applications.
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Analyzing scale effects of population density with Shenyang city as a case
- DU Guo-Ming, ZHANG Shu-Wen, ZHANG You-Quan
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2007, 24 (2):
186-192.
DOI: 10.7523/j.issn.2095-6134.2007.2.008
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Abstract (
1626 )
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Population density is an index of studying population distribution pattern. But scale effects of population density have not been paid attention that should be paid in the past. Studying Shenyang city as a case, after spatializing population census data, this paper analyzes similarities and differences of population in ten kind of grains from statistical characters, spatial auto-correlation and spatial pattern, and proves that there are scale effects in population density. This paper argues that when using the index of population density to research urban population distribution pattern, the researchers have to confront scale effects, choose feasible scale, and pay more attention to scale of data sources, scale of analyzing, scale of results expressing and relationship among them and scaling.
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Inspection of nutrients uptake and distribution across rhizosphere at seedling stage of soybean by rhizobox method
- JIN Jian, WANG Guang-Hua, LIU Xiao-Bing, WANG Guo-Dong, Stephen J Herbert
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2007, 24 (2):
193-200.
DOI: 10.7523/j.issn.2095-6134.2007.2.009
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Abstract (
1540 )
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Plant affects micro-ecological characteristics of rhizosphere. The nutrients (N, P, K, Ca, Mg, Fe, Mn, Zn and Cu) uptake and its distribution across rhizosphere at seedling stage in two soybean genotypes were investigated by rhizobox method. The results showed that the uptakes of N, P, K, Ca, Mg, Mn, Zn and Cu in a high yielding genotype, i.e. Beifeng 11, were higher than that in a low yielding genotype, i.e. Hai 9731, and the greater absorptions of N、P、Ca and Mg per root length and per root surface area were found in Beifeng 11, which indicated that Beifeng 11 had a relatively high root activity. The distribution characteristics of nutrients across rhizosphere were different. The soluble N and Mn concentration within 0~4 mm of rhizosphere was higher than bulk soil (>10 mm), whereas a negative trend was found for the P, K, Mg and Cu. The difference of nutrient concentration in rhizosphere between the two genotypes was obvious. The nutrients in the central compartment and the near zone for Beifeng 11 were higher than Hai 9731, except for K and Fe. Beifeng 11 had lower pH within 0~6 mm of rhizosphere.
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Effects of Chinese herbal formula on growth performance and serum biochemical parameters in weaned piglets
- YIN Fu-Gui, KONG Xiang-Feng, LIU He-Jun, YIN Yu-Long, LIAO Yi-Ping
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2007, 24 (2):
201-206.
DOI: 10.7523/j.issn.2095-6134.2007.2.010
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Abstract (
1473 )
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The experiment was conducted to determine the effects of dietary additive of Chinese herbal formula on growth performance, diarrhea index, serum biochemical parameters and peptic index in early-weaned piglets. Sixty piglets weaned at 21 days of age were randomly assigned to 3 treatment groups, representing supplementation with 0 or 2 g/kg of the herbal formula or 0.2 g/kg of colistin to maize- and soybean meal-based diets (n = 20 per group). Dietary supplementation with the formula could increase weight gain and feed efficiency (P<0.05), and effectively prevent piglets from diarrhea (P<0.05). Such functions of the formula were equal to or stronger than those of colistin’s. On d7, the concentration of TG in the formula group was significantly lower than that in supplement-free group (P<0.05); On d14, the activity of GOT in the formula group was significantly higher than that in colistin group (P<0.05), and the activity of CK was lower (P<0.05) than that in colistin group and supplement-free group; On d28, the activity of AMY in the formula group was significantly higher than that in colistin group and supplement-free group, and CK significantly lower than that in colistin group (P<0.05). Collectively, these findings indicate that the herbal formula is safe and effective in preventing the weaning-associated intestinal dysfunction and improving the growth performance in piglets.
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Model reduction and parameter sensitivity analysis of the TNFα-induced NF-κB signal transduction networks
- JIA Jian-Fang, LIU Tai-Yuan, YUE Hong, WANG Hong
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2007, 24 (2):
207-216.
DOI: 10.7523/j.issn.2095-6134.2007.2.011
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Abstract (
1509 )
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In order to study the impact of inner structure of biological systems and variations of correlative parameters on nuclear transcription fator-κappa B(NF-κB) signal transduction networks, it is vital to make sensitivity analysis of system parameters and to reduce mathematical model of NF-κB signal transduction networks, which includes 26 state variables and 64 parameters. Based on the analysis of mathematical model of the TNFα-Induced NF-κB signal transduction networks, the IκB Kinase complex（IKK）was chosen as step input signal of the system and NF-κB nuclear(NF-κBn) as measurable output signal. The direct differential method(DDM) was utilized to analyse sensitivity coefficients of oscillatory signal NF-κBn with respect to 64 parameters. Then, 9 parameters, which are less sensitive to system output signal, were removed form mathematic model of NF-κB signaling system so as to suitably reduce complexity of the system model. The simulation results show that output signal NF-κBn of the reduced model has much the same oscillatory characteristic as that of the former model. On the other hand, it also can be found that the rest output signals of both models are similar on the whole. Therefore, parameters sensitivity analysis and model reduction results can give new insights to analyse biological data, to build mathematical model and to design particular experiments.
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Effect of STZ-induced diabetes on bone mineral density and testosterone
- FEI Yu-Rong, WEI Dan, LI Ming, ZHANG Min, ZHANG Xiao-Lin, DING Wen-Jun, YANG Jian-Hong
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2007, 24 (2):
217-222.
DOI: 10.7523/j.issn.2095-6134.2007.2.012
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Abstract (
1262 )
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Objective: To investigate the effect of diabetes mellitus on bone metabolism, bone mineral density (BMD) and serum testosterone were studied in STZ-induced diabetic male rats. Materials and methods: Male Wistar rats were randomly divided into control group (n = 6), diabetic group (n = 5) and insulin-treated diabetic group (n = 5). Diabetes was intravenously induced by injection of streptozotocin (STZ, 50 mg/kg body weight), confirmed by 12 h fasting blood glucose concentration (12 mmol/L). The treatment group was subcutaneously injected with protamine zinc insulin (1.8-2.2U/animal) at the same time every day. The experiment lasted 32 days. Femoral BMD was determined by dual-energy X-ray absorptiometry (DEXA). Serum testosterone was detected by Enzyme-linked Immunosorbent Assay (ELISA) kit. Total alkaline phosphatase (ALP), calcium (Ca) and phosphorus (P) in serum were measured by bio-machine. Results: Femoral BMD in diabetic group was significantly lower than that in control (P < 0.01) but reserved by insulin treatment. Testosterone in serum was also reduced in diabetic rats (P < 0.01) and normalized by insulin treatment. Serum ALP concentration was markedly higher in diabetics (P < 0.01) compared to the controls and prevented by insulin treatment. However, no significant differences were observed in serum Ca and P among three groups. Conclusion: BMD is seriously affected by diabetes. Insulin deficiency and testosterone decrease are important causes of diabetic osteoporosis. And insulin treatment preserved bone loss and testosterone depression.
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Biological effects of chromium-rich brewer yeast in STZ-induced diabetic rats
- ZHANG Min, LI Ming，FEI Yu-Rong，YANG Jian-Hong, DING Wen-Jun
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2007, 24 (2):
223-228.
DOI: 10.7523/j.issn.2095-6134.2007.2.013
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Abstract (
1188 )
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Chromium (Cr) is an essential element for carbohydrate and lipid metabolism. However, inorganic chromium is poorly absorbed by the gastrointestinal tract of both humans and animals. The chromium-rich yeast (Cr-Y) with its better bioavailability can enhance the intestinal absorption of Cr in the body. The aim of this study is to evaluate the effects of chromium-rich yeast, normal brewer yeast (N-Y) and chromium acetate (CrAc) on STZ-induced diabetic rats. Diabetic rats were continuously gavaged with Cr-Y and chromium acetate 300 μg Cr/kg.bw.d, and N-Y 0.5 μg Cr/kg.bw.d for 32 days. The diet consumption, water drinking and body weight were recorded daily. The result showed that body weight in Cr-Y, N-Y, and chromium acetate groups were significantly increased than that in diabetic group (P < 0.01). The level of oral glucose tolerance test (OGTT) in Cr-Y group was markedly elevated as compared to N-Y, Cr-Ac and diabetes groups. Moreover, the levels of serum triglyceride (TG) and creatine in Cr-Y group were significantly decreased. But serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels did not show any changes compared to the controls. The results suggested that the supplementation of Cr-rich yeast can lower blood glucose levels and improve lipid profile in diabetic rats.
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The modification of MA-CDFRFT algorithm used in computing discrete fractional fourier transform
- CHEN Peng, HOU Chao-Huan, MA Xiao-Chuan
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2007, 24 (2):
229-234.
DOI: 10.7523/j.issn.2095-6134.2007.2.014
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Abstract (
1767 )
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The MA-CDFRFT(Multiangle Centered Discrete Fractional Fourier Transform) algorithm which is based on the eigendecomposition of the centered version DFT matrix makes full use of the FFT operation to reduce the computations in computing a group of DFRFT operations. Combining the symmetry principle of DFT(Discrete Fractional Fourier Transform) operation with even number, expands the one-dimensional symmetry principal in MA-CDFRFT algorithm to the two-dimensional plane of frequency and transform order according to the mathematical derivation. Utilizing this two-dimensional symmetry principle, the modified algorithm decreases the computations of the original algorithm to approximately one half. And the simulation test proves the correctness of the modified algorithm.
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Error analysis of ionospheric dispersion on dual-frequency altimetry
- XU Xi-Yu，LIU He-Guang
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2007, 24 (2):
235-240.
DOI: 10.7523/j.issn.2095-6134.2007.2.015
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Abstract (
1340 )
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Radar altimeters selects full-deramp technology in pulse compression, and apply two frequencies to reduce the ionospheric range errors. These will, as this paper shows, introduce an effect called “Ionospheric Dispersion”, especially in lower frequency, and this can lead to errors in height estimation. No foreign document is accessible to solve this problem, so this paper attempts to illustrate it. The authors at last draw the conclusion that these errors can be treated similarly as the quadratic phase errors, whose nature and solution are well-established, and they also discussed the magnitude of this error for a typical altimeter. Furthermore, the actual Doppler errors are deduced are it is shown that the existent Doppler algorithms are adequately accurate. Finally, by computer simulation, the sidelobes introduced to the system point target response are illustrated and the errors are estimated.
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Content-based clustered P2P search model depending on set distance
- WANG Jing, ZHANG Huan-Jie, YANG Shou-Bao, GAO Ying
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2007, 24 (2):
241-247.
DOI: 10.7523/j.issn.2095-6134.2007.2.016
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Abstract (
1212 )
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In content-based unstructured P2P search system, the main issues that affect query efficiency and searching cost are the complexity of computing document similarity brought by high dimensions and the great deal of redundant messages coming with flooding. Content-based cluster P2P search model depending on set distance is proposed in this paper to reduce the query time and redundant messages. This model defines document similarity by set distance to restrain the complexity of computing the document similarity in linear time. Also, clustering peers based on content depending on set distance reduces the query time and decreases the redundant messages. Simulations show that this model not only has higher recall, but also reduces the search cost and query time to the rate of 40% and 30% of Gnutella.
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QoS control of video transmission in MANET based on wavelet fractal interpolation
- LI Su-Xia, ZHANG Can, WU Wei-Ren
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2007, 24 (2):
248-252.
DOI: 10.7523/j.issn.2095-6134.2007.2.017
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Abstract (
1386 )
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Mobile wireless Ad Hoc networks (MANET) interconnect with Internet, satellite and the third generation mobile communication system by multi-hop, they forms the next generation Ad hoc network, which performs the merging and resources sharing in heterogeneous networks. The bandwidth and power are limited and there are all kinds of transmission errors in the environment of MANET, according to these characteristics of the next generation MANET, we propose a QoS control method for video transmission, based on directional-selective fractal interpolating. The simulated result shows that this new method has better performance than existing algorithms (such as bilinear interpolation), and can be adaptive to track the dynamic change of bandwidth.
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On the untraceability of two group signatures
- CAO Zheng-Jun
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2007, 24 (2):
253-256.
DOI: 10.7523/j.issn.2095-6134.2007.2.018
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Abstract (
1431 )
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Group signature allows individual members to make signatures on behalf of the whole group. It can be used to constitute a very useful primitive in many settings, such as E-cash, E-auction and E-election. In this paper, we show that the two group signatures proposed by Zhang et al. in 2003 and Kim et al. in 1996 are untraceable by very simple attacks. In contrast to those attacks presented by Wang et al., the techniques developed in this paper are novel and interesting.
简报
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Analysis of distributed firewall policy configuration mistakes and their detection
- WANG Wei-Ping, CHEN Wen-Hui, ZHU Wei-Wei, CHEN Hua-Ping, YANG Jie
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2007, 24 (2):
257-265.
DOI: 10.7523/j.issn.2095-6134.2007.2.019
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Abstract (
1442 )
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As a traditional information security technology (IST), distributed firewall is playing an important role while some problems exist within. Conflicts always appear in distributed firewall policy which brings out the security menace. After discussions of some relations between the rules of firewall, this paper demonstrates the probable mistakes which might exist in policy configuration, and also introduced an algorithm of mistake-detecting about policy configuration. Finally, the direction of further researching is also presented.
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