Table of Content

25 September 2017, Volume 37 Issue 5

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Convergence for a class of second-order functional differential equations with initial condition

WANG Peiguang, FU Fangfang, BAO Junyan

2017, 37(5):  449-453.  DOI: 10.3969/j.issn.1000-1565.2017.05.001

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The quasilinearization method is applied to discuss the convergence of the solutions for a class of second-order functional differential equations with initial condition in Banach space. We obtain the solutions for quadratic convergence of the approximate solutions.

Optimal convex combination bounds for the power mean

MENG Xiangju,TIAN Shuhuan,XU Huifeng

2017, 37(5):  454-456.  DOI: 10.3969/j.issn.1000-1565.2017.05.002

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The optimal value of parameters are obtained to make the following double inequality holds for all a,b>0,2M_r(a,b)≥G(a,b)+C(a,b)and A(a,b)+C(a,b)≥2M_r(a,b)where M_r(a,b),G(a,b),C(a,b),A(a,b)denote the power mean,the geometric mean,the contraharmonic mean, the arithmetic mean of two different positive numbers a and b respectively.

Periodic solutions and their bifurcation of Duffing system with strong non-linearity

WANG Xu, LI Xinye, WANG Zhenjing, HAN Shankai

2017, 37(5):  457-463.  DOI: 10.3969/j.issn.1000-1565.2017.05.003

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Based on the generalized harmonic balance method, the period-m responses of free and forced Duffing oscillators are constructed and compared with numerical solutions from which the effects of nonlinear term and excitation parameters can be observed. For free vibrations, the response periods are assumed to be integer times of the natural period of the corresponding linear system and the excitation period respectively. It is shown that the number of harmonic terms should be large enough for both strongly nonlinear systems and period-doubling bifurcation solutions with large period so that the approximate analytic solutions are comparative to numerical results.

On preparation and properties of composite nano-TiO₂ transparent photocatalyst emulsion

LI Xiaowei,ZHAO Kaifeng,HU Xiaoxue,LU Qi,SUI Huidong,LI Jianwei, LIU Shuang

2017, 37(5):  464-470.  DOI: 10.3969/j.issn.1000-1565.2017.05.004

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Boron/fluoride co-doped nano TiO₂ colorless and transparent hydrosol was synthesized by a novel complexation-controlled hydrolysis method at room temperature by using TiCl₄, oxalic acid, NH₃·H₂O, ammonium fluoride, and boric acid etc as raw materials. The sample with the acid red 3R was studied by the photocatalytic degradation under simulated sunlight irradiation. To study the effects of reflux time, pH and-concentration and reaction conditions of the synthesis process and properties of the materials, the optimum preparation conditions were found out. The results show that when the doping amount is 0.003 mol/L, the pH value is 6, the reflux time is 15 min, the photocatalytic activity of doped nanometer TiO₂ is the highest. The degradation rate of acid red 3R dye solution with the concentration of 50 mg/L was more than 98% after the sun exposure.

Threshold of nucleation barrier of spherical Si nanoparticle prepared by heat annealing

DENG Zechao, FU Nian,CHU Lizhi, DING Xuecheng, FU Guangsheng, WANG Yinglong

2017, 37(5):  471-475.  DOI: 10.3969/j.issn.1000-1565.2017.05.005

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Amorphous Si films were prepared by pulsed laser ablation in vacuum at room temperature. These samples were heated by annealing furnace in order to transform into crystalline film. Threshold of nucleation barrier and mean diameter of Si nanoparticle were determined through the results of SEM, Raman and XRD, which were 850 ℃ and 15 nm, respectively. If the shape of nanoparticle is assumed to be ideal sphere, we can obtain the magnitude of threshold nucleation barrier for the nanoparticle through calculation, which is in the order of 10^-11 mJ.

Fluorescence-detected stopped-flow kinetic investigation of thioflavin T binding onto the amyloid fibril of lysozyme

MA Gang, QIN Zhe, LIU Siyang, SHANG Yanli, JIA Baohuan

2017, 37(5):  476-482.  DOI: 10.3969/j.issn.1000-1565.2017.05.006

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Deposition of amyloid fibrils in tissues and organs is relevant to a wide range of devastating human diseases, including Alzheimer’s disease, Parkinson’s disease, and type Ⅱ diabetes. Thioflavin T(ThT)is widely used as a fluorescent probe for qualitative and quantitative detections of amyloid fibrils. Yet the exact kinetic mechanism of ThT binding onto amyloid fibril remains elusive. In this study, we used fluorescence-detected stopped-flow technique to study the binding mechanism of ThT onto the amyloid fibril of hen egg white lysozyme induced by guanidine hydrochloride. We proposed a kinetic binding mechanism to interpret our experimental observations. Our results showed that the binding of ThT onto lysozyme fibril follow a dual-site parallel binding mechanism. We believe our work is beneficial for better understanding of the interaction between fluorescent dye and amyloid fibril.

Preparation of N doped three dimensional graphene and its electrochemical performance

WANG Yansu, ZHAN Yali, YAN Xiyang

2017, 37(5):  483-488.  DOI: 10.3969/j.issn.1000-1565.2017.05.007

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To explore more environmental friendly method of preparing three dimension reduced graphene oxide, herein, using L-Asparagine as nitrogen source and vitamin C as green reductant, we proposed a simple one step hydrothermal method. After reaction at 90 ℃ for 1,2,3,5,10 h and then freeze-drying, the three dimensional N doped graphene aerogel is prepared. And the test, conducted under three electrode system indicates that the material with 3 h reaction time shows better electrochemical performance, smaller internal resistance. The specific capacitance is 173.8 F/g at current density of 1 A/g. And after 1 000 times charge and discharge cycles, the specific capacitance remain at a rate of 83%. In addition,it has lower internal resistance(0.6 Ω). In summary, the material has excellent power performance and capacitance behavior.

Determination of related substances in edoxaban tosilate hydrate by HPLC

LI Zhiwei,ZHANG Renfei,LIU Yingna,YU Yeguang,XIE Yinghua,QIU Yan

2017, 37(5):  489-496.  DOI: 10.3969/j.issn.1000-1565.2017.05.008

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A HPLC method was established to separate edoxaban tosilate hydrate and its related substances. SunFire C8(250 mm×4.6 mm, 5 μm)column was adopted in the analysis method and its temperature was kept at 30 ℃. The mobile phase A consisted of 20 mmol/L K₂HPO₄(pH 4.0)-acetonitrile(90∶10, V/V)and the mobile phase of B consisted of 20 mmol/L K₂HPO₄(pH 4.0)-acetonitrile(30∶70, V/V). A gradient elution at flow of 1.0 mL/min was used. The detection wavelength was 290 nm and the injection volume was 10 μL. The calibration curve of all substances were linear in appropriate concentration range, and the average recovery of all compounds were among 98.0%~102.0%, RSD(n=9)values were less than 2.0%. Each impurity was separated when the parameters had small changes and the assay variation of impurities was accepted. Methodology validation results proved that the method had good selectivity, high sensitivity, high accuracy and good robustness and it can be used for quality control of edoxaban tosilate hydrate.

CCA analysis of colonization of DSE in the rhizosphere of Ammopiptanthus mongolicus in relation to soil factors

WANG Shaojie, HOU Lifeng, XIE Linlin, HU Congcong, HE Xueli

2017, 37(5):  497-507.  DOI: 10.3969/j.issn.1000-1565.2017.05.009

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Ammopiptanthus mongolicus is the only evergreen broadleaf shrub grown in the northwest China that has the characteristics of cold and drought resistance, salt resistance and wind resistance. It plays an important role in windbreak and soil and water conservation. To elucidate the spatial distribution of dark septate endophytes(DSE)and the relationship of DSE with soil factors associated with the desert plant A. mongolicus based on canonical correspondence analysis(CCA), the author sampled from five different sites in northwest China in July 2015, which are Wuhai, Dengkou, Alxa, Minqin and Shapotou, respectively. Root samples were collected from four robust A. mongolicus,and soil samples were taken from the rhizosphere of A. mongolicus in five sites and divided into five depth intervals, 0-10 cm, 10-20 cm,20-30 cm, 30-40 cm and 40-50 cm, respectively. The results showed that the roots of A. mongolicus could be infected highly by DSE and formed a typical type of septate hyphae and microsclerotia. The distribution of DSE was significantly affected by ecological conditions. There were significant differences in distribution of DSE among the five sites. The colonization rates of DSE among the five sites exhibited a pattern as Alxa>Wuhai>Shapotou>Minqin>Dengkou. The average colonization rate of five sites was 52.02%, which showed that A.mongolicus and DSE could form a symbiotic relationship. There were also significant differences in soil factors among different sites. In the same site, DSE distribution and soil indicators had the maximum values in the profile of a surface layer and showed the trend of decreasing with the depth of the profile. The results of CCA showed that DSE hyphae, microsclerotia, colonization rate and colonization intensity in the axis of CCA got better differentiation. The species-environment biplots were drawn based on the result of CCA. The relationships between the colonization of DSE and the seven soil factors were clearly revealed on these biplots. Accoding to the biplots, the main soil factors of five sites were different. The acid phosphatase(ACP), alkaline phosphatase(ALP)and available phosphate were found to be main soil factors affecting the hypha colonization of DSE in Wuhai. The main soil factors of Dengkou were available nitrogen and organic carbon. The hypha colonization of DSE in Alxa were mainly affected by ALP and pH. The main soil factors affecting the hypha colonization of DSE were pH, ALP and Urease, in Minqin. And the main soil factors affecting the hypha colonization of DSE in Shapotou were ACP, Urease and available nitrogen. The research results showed that the distribution of DSE in different regions was affected by different soil factors, which could provide the basis for the evaluation and improvement of soil conditions in the desert area.

Biodiversity of the darkling beetles of the Hunshandake desert from Inner Mongolia

SUN Xiaojie, GUO Yuanchao, REN Guodong

2017, 37(5):  508-517.  DOI: 10.3969/j.issn.1000-1565.2017.05.010

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The Hunshandake desert is situated in the southeast region of Mongolian Plateau which owns unique geographical location with high diversity of darkling beetles. 1 244 darkling beetles specimens were collected by us did filed investigation in this area where contains large insect resources. After the specimens were identified, we found they belong to 35 species(subspecies), 14 genera, 8 tribes and 4 subfamilies. In this paper, a list of darkling beetles found in the desert was provided, and listed information of collection and regions distribution for each species. A classified key of species was prepared. The darkling beetles in Hunshandake desert were analyzed fauna component and characteristics of distribution, and compared richness with other 7 deserts in Inner Mongolia.

Screening and identification of xylanase-producing endophytic bacteria of Cymbidium faberi roots

MA Chunling, LI Sihan, ZHAO Dongfang, LI Guangshuo, MA Ruiyi, SUN Lei

2017, 37(5):  518-522.  DOI: 10.3969/j.issn.1000-1565.2017.05.011

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In order to obtain the xylanase-producing functional strains, 592 endophytic bacteria from Cymbidium faberi roots were screened by using the method of Kongo red dye according to the size of hydrolyzed circle. The xylanase activity of strains screened was re-screened by DNS. The xylanase-producing strain was identified based on its morphological, physiological and biochemical characteristics, mole fraction of(G+C)and 16S rRNA gene sequence analysis. The results showed that 31 xylanase-producing strains were obtained, which account for 5.23% of the total strains. Seven strains with high xylanase yields were screened through DNS method. Strain 6hRe76 with the highest enzyme activity was obtained, of which the activity of xylanase was 57.15 U/ mL. The strain 6hRe76 was identified as Paenibacillus kribbensis. The research provided the new source for xylanase production.

Biosorption of cadmium ions from solution by nonliving Saccharomyces cerevisiae

DAI Qunwei, WANG Ke, WANG Yan, LI Gang

2017, 37(5):  523-530.  DOI: 10.3969/j.issn.1000-1565.2017.05.012

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The nonliving Saccharomyces cerevisiae was utilized as biosorbent to remove Cd²⁺ from aqueous solution.The effects of initial pH, amount of adsorbent ρa, initial concentration of Cd²⁺ ρ</sub>0 on the adsorption efficiency of Cd²⁺ were studied. Meanwhile, the adsorption kinetics, isotherm biosorption and SEM/EDS were investigated. The results indicated that the optimum condition for biosorption were as follows: pH=4.5~7.0, ρ</sub>a=4.0~6.0 g/L, ρ</sub>0=112.4~224.8 mg/L. The analysis of adsorption kinetics showed that the biosorption of Cd²⁺ by Saccharomyces cerevisiae was a rapid process.The biosorption process could be fitted with the pseudo-second-order kinetic model. The isotherm adsorption curve of Cd²⁺ on baker’s yeast accorded well with Langmuir and Freunlich model. Through SEM/EDS analysis, we can see that baker’s yeast cell surface tends to absorb large amounts of Cd²⁺ after being adsorbed for 1 440 minutes.As a consequence,nonliving Saccharomyces cerevisiae have a high biosorption efficiency for Cd²⁺.</sub>

Multi-center encryption scheme for weight attributes of ciphertext policy in cloud computing environment

DU Ruizhong,ZHAO Fanghua

2017, 37(5):  531-536.  DOI: 10.3969/j.issn.1000-1565.2017.05.013

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In the attribute encryption scheme based on the ciphertext policy,the central authorization center(CA),as an important organization involved in generating the private key of the user attribute,thus, the central anthorization center is required for the high security.In the traditional scheme, if the single CA is attacked, the security of the system can not be guaranteed.In order to solve this problem, the paper adopts the multi-authorization center.In this scheme, each CA calculates the decryption key of the user at the same time.The attribute authority(AA)manages the corresponding attribute set and divides the attribute weight according to the attribute set to realize weight attributes.By the theoretical analysis, the scheme not only ensures the security of the scheme,but also makes it more practical.

A LARS scheduling algorithm based on classification improvement and its dynamic parameter performance analysis

HE Zhiqiang, LIN Yongjun

2017, 37(5):  537-544.  DOI: 10.3969/j.issn.1000-1565.2017.05.014

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Aiming at the demand of industrial ethernet and office network information integration, this paper studies the problem of improving the quality of network service in multi-service network based on LARS scheduling algorithm. The principles, advantages and disadvantages of LARS are studied,and a method for improving LARS by using data classification technology is proposed. The forwarding performance test under different parameters proves that the method can preserve LARS’s basic characteristics, can effectively improve the efficiency of the implementation of LARS, and has a good robustness.

Customer project status tampering algorithm based on time series analysis

CHEN Chaofan, LIN Shuxin

2017, 37(5):  545-554.  DOI: 10.3969/j.issn.1000-1565.2017.05.015

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The existing customer project status recognition algorithm can not adaptively identify the tampering type and can not simultaneously identify the tampering of multiple project states, the algorithm of tampering recognition based on time series analysis is given. The PCA VarSelect algorithm is used to derive the suspicious list of project status and further reduce the recognition range. The method is to determine the tampering state according to the tampering time period and the score deviation degree.On this basis,this method can further analyze the tampering period of time to determine the type of tampering and finally identify the corresponding tampered state of the project. Simulation shows that the algorithm has high recognition accuracy.It not only can identify the tampering state of a single project, but also can identify the tampering state of multiple projects at the same time.

Fair outsourcing computations scheme based on transferability

LI Haiying,ZHANG Jiangxiao,SUI Chunrong

2017, 37(5):  555-560.  DOI: 10.3969/j.issn.1000-1565.2017.05.016

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In outsourcing computations,there exist some problems such as the unfairness of outsourcing computations, the user and outsourcer is not anonymous, and the non-transferable of the outsourcing computations. This paper proposed a fair, full anonymous and transferable outsourcing computations scheme based on the transferable and conditional model. Using the Groth-Sahai's self-updating of commitment and corresponding proving, the new scheme guarantees that the user and outsourcers are fully anonymous. When the user didn't want to do the computation, he can transfer the computations to another. At last, these would improve the practicability of the outsourcing computations.