ISSN 0253-2778

CN 34-1054/N

2015 Vol. 45, No. 8

Display Method:
Ramification in relative quadratic extensions and fundamental units of real quadratic fields
2015, 45(8): 623-626. doi: 10.3969/j.issn.0253-2778.2015.08.001
Let F=Q(d) be a real quadratic field and ε=x+yd the fundamental unit of F satisfying NF/Q(ε)=1. Some connections between the ramification properties for dyadic prime ideals in quadratic extension F(ε)/F and congruence properties of x, y were established. As a corollary, some congruence properties about x, y were given when d=p1…pr or 2p1…pr with p1≡…≡pr≡1 mod 4 being distinct prime numbers.
Ruin probability of the Sarmanov structure among finance and insurance risks with regularly varying tails
CHEN Yu, GAO Wenxue
2015, 45(8): 627-632. doi: 10.3969/j.issn.0253-2778.2015.08.002
A discrete-time insurance risk model was considered, in which the insurance risks and financial risks follow jointly multivariate Sarmanov distributions, and the asymptotic formula for ruin probability was obtained.
Representation of general solutions to hybrid fractional-order differential equations with multiple time delays
2015, 45(8): 633-637. doi: 10.3969/j.issn.0253-2778.2015.08.003
The representation problem of general solutions of hybrid linear fractional-order differential systems with multiple time delays was discussed. Based on Gronwall-Bellman integral inequality, the exponential estimates of the solutions of this equation were derived. The general solution to hybrid linear homogeneous fractional-order differential equations with multiple time delays was derived by means of the fundamental solution of the homogeneous systems and the Laplace transform method, then the general solution of the nonhomogeneous systems was obtained by means of Laplace inverse transform and convolution theorem.
A generalized interior shock layer solution to nonlinear singularly perturbed equations
CHEN Huaijun, SHI Lanfang, MO Jiaqi
2015, 45(8): 638-642. doi: 10.3969/j.issn.0253-2778.2015.08.004
A class of singular perturbation problem of the reaction diffusion initial value equation was studied. Under suitable conditions, the generalized outer solution to reduced problems was considered. Then the interior shock and boundary layer correction solutions to the original problem were constructed by using the theory of generalized functions. Finally, using the fixed point theorem, the uniform validity of the generalized asymptotic solution with interior shock and initial layers was proved.
Detection of caspase-3 by fluorescence quenching effect of a self-assembly nanoparticle
HAN Xiaosan, LIANG Gaolin
2015, 45(8): 643-648. doi: 10.3969/j.issn.0253-2778.2015.08.005
Caspase-3 is a very important protease in cell apoptosis and plays a crucial role in many diseases. A new probe Ac-Asp-Glu-Val-Asp-Cys(StBu)-Lys(FITC)-CBT (1) was reported, which can be reduced by TCEP and cleaved by caspase-3 to yield the amphiphilic dimer (1-D).1-D can quickly self-assemble into nanoparticles to induce a clear fluorescence quenching effect because of the aggregation-caused quench. The nanoparticles were characterized by means of dynamic light scattering (DLS), transmission electron microscope (TEM), and high performance liquid chromatography (HPLC). As a result, the fluorescence intensity has a linear correlation with the concentration of caspase-3, which could be applied to sensing caspase-3 activity in vivo in the future.
Calcium phosphate nanoparticles for the delivery of the prodrug of cisplatin
ZENG Bingru, SHI Hongdong, LIU Yangzhong
2015, 45(8): 649-654. doi: 10.3969/j.issn.0253-2778.2015.08.006
Drug delivery systems can facilitate the delivery of platinum-based drugs, enhance drug efficiency and protect Pt(Ⅳ) from being reduced before cellular uptake. A highly biocompatible Pt(Ⅳ) prodrugs delivery system using calcium phosphate (CaP) nanoparticles with simple preparation procedures were reported. The diameter and morphology of Pt(Ⅳ)/CaP nanoparticles were characterized by dynamic light scattering, scanning electron microscope and X-ray diffraction. Then cellular uptake efficiency and cytotoxicity were studied. The results indicate that nanoparticles are well-dispersive with narrow size distribution; they have high cellular uptake efficiency and redox response so as to release cisplatin after being reduced by cellular reductants. Moreover, the delivery system demonstrates a significantly higher inhibitory effect than the free Pt(Ⅳ) prodrug.
Relationship between wetland change and local climate in the semi-arid zone of the Songnen Plain
LIU Yan, LIU Jiping, SHENG Lianxi
2015, 45(8): 655-664. doi: 10.3969/j.issn.0253-2778.2015.08.007
Wetlands are most sensitive to climate change, and their growth and decline can influence climate change. In order to express more intuitively the relationship between wetland change and a local climate in its semi-arid zone, the spatio-temporal characteristics of wetland change in the semi-arid zone of the Songnen Plain from 1985 to 2010 was studied, and the impact of large areas of wetland change on the local climate was analized by means of the empirical analysis and statistical method. Results showed that because of the increase of paddy fields, the total area of wetland in the studied area was on the rise. The wetland change produced an impact on the local climate, mainly on maximum temperature and precipitation during the period of May to September. The growth of the wetland area could reduce the increment of maximum temperature and the decrement of precipitation, and the decrease in wetland area could increase the increment of maximum temperature and decrement of precipitation. The changes in maximum temperature and precipitation corresponded respectively with wetland change in spatial distribution. Wetland change played a more important role in moderating local climate compared to the contribution of woodland and grassland change in the studied area. Therefore, the cold-humid effect of wetlands is the key factor in regulating local climates and mitigating climate warming.
Large eddy simulation of mixing characteristic of jet in supersonic crossflow
CAO Changmin, ZHAO Majie, ZHOU Taotao, YE Taohong
2015, 45(8): 665-673. doi: 10.3969/j.issn.0253-2778.2015.08.008
Large eddy simulation was performed to study the large scale vertical structures and the mixing characteristic of supersonic transverse injection flow in the Gamba combustor. The supersonic flow is obstructed by the sonic jet,resulting in very complex three dimensional shock waves and vertical structures. All of the shock waves, including bow shock, λ shock, expansion shock, barrel shock and Mach disk, can be seen in the mean Mach number contour. The three-dimensional vertical structures, such as steady counter-rotating vortex pairs (CVP), trailing counter-rotating vortex pairs (TCVP), horseshoe vortices and unsteady jet shear layer vortices, can be visualized by the iso-surface of Q-criterion. The TCVP structure rotates in the opposite direction of the CVP, which can be characterized by the average streamline. Moreover, the asymmetric CVP structure leads to non-uniform distribution of fuel mass fraction in span-wise direction. The probability density functions (PDFs) were introduced to study the mixing characteristic in the near field, far field and the recirculation regions in the upstream of the jet. The results show that significant mixing occurs in the recirculation regions, the bottom of the barrel shock and the wake below the jet shear layer. The PDFs of mixture fraction obey β distribution in the near jet flow-field and develop into Gauss distribution in the downstream. The study of the concentration decay shows that the H2 mass fraction obeys exponential decay along the maximum centerline with the index being about -07.
Simulation of thermal-radiating wall with hot water coils partly paved and the influence of installed area size on thermal comfort
ZHAO Yuqian, XU Bin
2015, 45(8): 674-682. doi: 10.3969/j.issn.0253-2778.2015.08.009
The wall radiating heating system was studied, and a conception of hot water coils partly paved in the wall is presented. A heat transfer model was established to simulate the thermal performance of the wall by Fluent. The average heat flux, temperature and temperature distribution of the thermal-radiating wall under unsteady conditions were analyzed. The influence of installed area size on indoor thermal comfort was also analyzed. The results show that when the temperature difference between inlet and outlet water is 5 ℃,rate of flow is 03 m3·h-1, tube spacing is 250 mm, and the area of partly paved coils is 2/3 of the fully paved area, PMV(predicted mean vote) is -028, PPD(predicted percentage of dissatisfied) is 7%, the values are in the range of thermal comfort; when the proportion reaches to 5/6, PMV is +014 and PPD is 5%, the indoor thermal environment is the most comfortable; while when the wall is fully paved, PMV is +05 and PPD is 10%, indoor thermal comfort is reduced. The wall with hot water coil partly paved can economize on materials in comparison with a fully paved wall, and it can save energy effectively while delivering themal comfort.
The MFCCA algorithm and its application in financial market: A new view of multifractal extension of DCCA
DA Tingting, ZHANG Shuguang, DA Cheng
2015, 45(8): 683-691. doi: 10.3969/j.issn.0253-2778.2015.08.010
Multifractal extension of detrended cross-correlation analysis (DCCA) usually involves the trouble that the computation of arbitrary powers of the negative cross-covariances leads to complex values. However, a commonly adopted modulus processing method MFDXA often indicates significant multifractal cross-correlation signal when actually no fractality exists. Mulitfractal cross-correlation analysis (MFCCA) proposed by Os′wiecimka preserves the sign of the cross-covariances and settles the trouble above. MFCCA is a natural general extension of MFDFA and DCCA. Here it was demonstrated that MFCCA performs more effectively and powerfully than MFDXA from the view of the general two-component ARFIMA processes model. MFCCA can correctly identify the signal of multifractality behavior and show sensitivity to the varying of the weight parameter W.
Sellers optimal ordering quantity and pricing when considering consumer valuation bias
2015, 45(8): 692-701. doi: 10.3969/j.issn.0253-2778.2015.08.011
Valuation bias, i.e., sonsumers initial valuation before purchasing that is different from the true valuation after purchasing, often occurs in online shopping and will lead to consumers returns and further affect sellers selling strategies. Two relationships between consumers initial valuation and the true valuation are considered: the mutual independence between the initial valuation and the true valuation, or their mutual dependence. First, based on these relationships, two corresponding models were built and optimal ordering quantity were given; then, the optimal decisions and expected profits are analyzed in the two models, and it was found that each model can only be conditionally optimal and the benchmark of the two models was given; finally, through numerical study, the effect of the characteristics of consumers valuation distribution on sellers optimal pricing, ordering quantity and profit was analyzed.
Innovation efficiency and influence factors of innovative enterprises in a region: A comparison between different sizes of enterprises in Anhui Province
LI Xingmin, WEI Jiuchang
2015, 45(8): 702-708. doi: 10.3969/j.issn.0253-2778.2015.08.012
In order to further understand the innovation activities in innovative enterprises within a region in China, from the perspective of large sized and small-medium sized enterprises (SMEs), the innovation efficiency of these enterprises and its influence factors were analyzed employing the data from 340 innovative enterprises in Anhui Province as a sample and the stochastic frontier approach (SFA). The results show that the innovation efficiency of these enterprises is at the medium level; the innovation efficiency of the large sized enterprises is at the same level as the SMEs and some of the SMEs have strong ability of innovation. As to the influencing factors, it is found that firm size has a positive impact on the innovation efficiency of the SMEs, but no influence on that of large sized enterprises. The R&D subsidies from the government have a negative impact on the innovative enterprises innovation efficiency, while tax breaks have a positive impact on it. Different approaches are to be adopted for large sized enterprises to improve innovation efficiency from those for small-medium sized enterprises.