Collect | Home Page 
   
Office Online  
Journal Online
· Forthcoming Articles
· Current Issue
· Archive
· Advanced Search
· View by Fields
· Archive By Subject
· Special Issues
· Download Articles
· Read Articles
· Email Alert
· Recommended
Links
·
·
·
·
·
·
·
·
·
·
·
   Science & Technology Review
2015, Vol.33, No. 18
28 September 2015

Exclusive
Articles
Reviews
Focus
Foreword
Columns
Book Reviews
Perspectives
Scientists
Science and Technology Fund
News Around
News Focus
Forum
Special Column of Science
Select | Export to EndNote
Columns

Hot!

Science & Technology Review. 2015, 33 (18): 3-3.
Full text: HTML (188 KB)  PDF  (1874 KB)  ( 103 )
Abstract ( 661 )

Science & Technology Review. 2015, 33 (18): 6-6.
Full text: HTML (185 KB)  PDF  (1836 KB)  ( 74 )
Abstract ( 650 )

Science & Technology Review. 2015, 33 (18): 8-8.
Full text: HTML (138 KB)  PDF  (1365 KB)  ( 63 )
Abstract ( 619 )

Science & Technology Review. 2015, 33 (18): 10-10.
Full text: HTML (141 KB)  PDF  (1395 KB)  ( 53 )
Abstract ( 614 )

Science & Technology Review. 2015, 33 (18): 11-11.
Full text: HTML (117 KB)  PDF  (1159 KB)  ( 124 )
Abstract ( 661 )

Science & Technology Review. 2015, 33 (18): 104-104.
Full text: HTML (148 KB)  PDF  (1467 KB)  ( 98 )
Abstract ( 670 )

Science & Technology Review. 2015, 33 (18): 105-105.
Full text: HTML (187 KB)  PDF  (1858 KB)  ( 77 )
Abstract ( 715 )

Science & Technology Review. 2015, 33 (18): 108-108.
Full text: HTML (173 KB)  PDF  (1717 KB)  ( 78 )
Abstract ( 583 )

Science & Technology Review. 2015, 33 (18): 112-112.
Full text: HTML (149 KB)  PDF  (1481 KB)  ( 189 )
Abstract ( 721 )

Science & Technology Review. 2015, 33 (18): 112-112.
Full text: HTML (149 KB)  PDF  (1481 KB)  ( 158 )
Abstract ( 784 )
Foreword

Science & Technology Review. 2015, 33 (18): 1-1.
Full text: HTML (50 KB)  PDF  (485 KB)  ( 403 )
Abstract ( 694 )
News Around

Science & Technology Review. 2015, 33 (18): 7-7.
Full text: HTML (40 KB)  PDF  (392 KB)  ( 80 )
Abstract ( 659 )
News Focus

Science & Technology Review. 2015, 33 (18): 9-9.
Full text: HTML (38 KB)  PDF  (371 KB)  ( 143 )
Abstract ( 648 )
Forum

Science & Technology Review. 2015, 33 (18): 12-12.
Full text: HTML (39 KB)  PDF  (382 KB)  ( 157 )
Abstract ( 879 )
Exclusive

Highlights of China high speed railway

LU Chunfang
Science & Technology Review. 2015, 33 (18): 13-19. ;  doi: 10.3981/j.issn.1000-7857.2015.18.001
Full text: HTML (370 KB)  PDF  (3687 KB)  ( 480 )
Abstract ( 1214 )
High speed railway (HSR) is an extremely huge and complicated system integrating many edge-cutting technologies. Via original innovation, integrated innovation and innovation by absorbing import technologies, China railway has explored a HSR development path with unique Chinese characteristics and become the world's largest and fastest growing HSR network. By reviewing the development history of HSR in China, this article presents an in-depth analysis on the distinctive characteristics of Chinese high speed railways, i.e., leading technologies, outstanding safety and reliability, and high cost-efficiency. The sophisticated technologies are embodied by the high running speed, complicated construction environment, diversified operation scenarios and compatibility with international technologies. For safety and reliability, a complete HSR technology system and safety assurance system have been established to reinforce control over engineering quality from the source and market access of products, intensify the operation management and enhance disaster prevention & control. The cost-efficiency is demonstrated in terms of construction period, cost, energy consumption, environmental performance and social benefit. Last but not the least, a vision on HSR in China is included, which also proposes that the railway should further concentrate on the national strategies of“one road and one belt”and“going global”, and make more effort to cement the leading position of Chinese HSR in the world.
Articles

PM10 and PM2.5 emission control by electrostatic precipitator (ESP) for coal-fired power plants VI: Optimization of HV power source with 75 t/h industrial boiler (Jiaxing Xiexin Environmental Power Plant)

MA Hongjin, XU Jianyuan, WANG Shilong, HAN Ping, ZHENG Qinzhen, LI Shuran, YAN Keping
Science & Technology Review. 2015, 33 (18): 20-22. ;  doi: 10.3981/j.issn.1000-7857.2015.18.002
Full text: HTML (1 KB)  PDF  (1504 KB)  ( 261 )
Abstract ( 654 )
This paper discusses the performance of a four-field electrostatic precipitator (ESP) used for a 75 t/h industrial coal-fired boiler. By using four traditional single-phase transformer-rectifiers (T/Rs), the PM10 and PM2.5 concentrations at the ESP outlet are around 120.4~219.7 and 9.6~22.3 mg·Nm-3, respectively. After retrofitting the four rectifiers with four ZH type three-phase T/Rs, the PM10 and PM2.5 concentration are about 6~17 and 1.8~3.3 mg·Nm-3, respectively. The PM2.5 to PM10 ratio ranges from 35% to 52%.

Influence of during south ion-absorbed-type rare earth deposit mining on groundwater and it's monitoring

WANG Jionghui, ZHANG Xi, CHEN Daogui, MA Chong
Science & Technology Review. 2015, 33 (18): 23-27. ;  doi: 10.3981/j.issn.1000-7857.2015.18.003
Full text: HTML (1 KB)  PDF  (4793 KB)  ( 617 )
Abstract ( 340 )
Ion-absorbed-type rare earth deposit which is the most important strategic resource is distributed extensively in the south of China, such as Jiangxi, Guangdong and Guangxi provinces. It often exist in the form of ions absorbed in clay minerals, and is characterized by middle-heavy rare earth enrichment, simple mining and leaching process and low cost. However, groundwater pollution of heavy metal, ammonia nitrogen and sulfate are very serious during mining. Therefore, it is urgent to perform groundwater monitoring in the mine. In Guangdong province, we used automatic monitoring facilities to perform groundwater dynamic monitoring experiments and made significant progress. Through this research, we obtained changing values of key indicators in the water, i.e., pH value, ammonia nitrogen, etc. In this paper, we present a new green mine environment monitoring system in ion-absorbed-type rare earth deposit. The system integrating in-situ leaching process, system of groundwater monitoring with wireless data transmission, and the control system of environment pollution is to control the influence on groundwater during the mining of ion-absorbed-type rare earth deposit. It may provide technical support for achieving the goal of green mining.

Triple-porosity and dual-permeability mathematical model for CBM vertical well

CAO Haitao, YI Xiangyi, CHE Xingxiang, LI Chengyong, WANG Xiaolei
Science & Technology Review. 2015, 33 (18): 28-33. ;  doi: 10.3981/j.issn.1000-7857.2015.18.004
Full text: HTML (1 KB)  PDF  (2131 KB)  ( 154 )
Abstract ( 344 )
Most of the coal reservoirs in China are of low-permeability and low-pressure, and the injection/fall off test is usually used to correctly evaluate formation parameters. But because water molecules can't enter the matrix porosity, the adsorption and desorption characteristics of the matrix can't be reflected. Concerning this issue, a triple-porosity and dual-permeability mathematical model has been established. Accurate solution to this model under different outer boundary conditions(Infinite, no flow and constant pressure)is obtained by use of Laplace transformation and Stehfest numerical inversion. According to the analysis in Laplace domain, the type curves of dimensionless pressure and pressure derivative are graphically illustrated. The pressure decline performance under the effects of CBM reservoir properties are discussed. A theoretical basis for CBM well test has been provided.

Characteristics analysis of well testing curve of CO2 flooding in low permeability reservoir

SU Yuliang, MENG Fankun, ZHOU Shiyu, HAO Yongmao, ZHOU Zhiwei, TONG Gang
Science & Technology Review. 2015, 33 (18): 34-39. ;  doi: 10.3981/j.issn.1000-7857.2015.18.005
Full text: HTML (1 KB)  PDF  (1629 KB)  ( 463 )
Abstract ( 697 )
On the basis of fluid distribution of carbon dioxide flooding in low permeability reservoir, the flowing areas are divided into CO2 region, CO2-oil transition region and oil unswept region. Considering the power law variation of fluid physical parameters in the transition region, we establish a varied property carbon dioxide flooding three-zone composite reservoir well testing model, and obtain the solution of bottom hole pressure by applying Laplace transform and Stehfest numerical inversion. In this way, the characteristics of variation of the well testing curve and influential factors are investigated. The results show that the slope of curves representing the transition section between the CO2 region and transition region and radial flow of the transition region is mainly affected by the power law exponent of mobility and storativity and mobility and storativity ratio in the CO2-transition region interface. The larger the storativity power law exponent and storativity ratio at the CO2-transition region interface is, the earlier the transition section between miscible region and oil unswept region begins, the lower the peak is. When the radius of the transition region is increased, the line of radius flow in the transition region becomes longer, the transition curve from the transition to oil unswept region shifts right, and CO2 injection pressure decreases.

Analysis of natural gas mercury content characteristics of Shuangtuozi gas field in Songliao Basin

HAN Zhongxi, WANG Shuying, YAN Qituan, GE Shouguo, WANG Chunyi
Science & Technology Review. 2015, 33 (18): 40-44. ;  doi: 10.3981/j.issn.1000-7857.2015.18.006
Full text: HTML (1 KB)  PDF  (1562 KB)  ( 177 )
Abstract ( 199 )
In order to sduty the natural gas mercury content characteristics and its origin in Shuangtuozi gas field, the author carried out natural gas mercury content and alkane carbon isotope analysis of 7 gas wells in the field. The result showed that natural gas mercury content is among 11-29200 ng/m3, and the average value is 17600 ng/m3, which makes it belong to medium and low mercury containing natural gas. The natural gas mercury content increases with the rise of the production depth, and the deep zone has a far greater mercury content than the shallow and middle zones obviously controlled by the basin's double layers structure. Our research showed that the natural gas mercury content is both relevant to the type of the natural gas and the maturity of the source rocks. The type of natural gas from the deep zone is coal type gas and those from the middle and shallow zones are a mixed gas of coal type gas and oil type gas. Different source rocks' thermal evolution levels are the major reason that makes the natural gas mercury content of Shuangtuozi gas field quite different from that of the neighbor Changshen gas field.

Phase analysis of iron ore tailings and preparation for autoclaved aerated concrete

WANG Changlong, YANG Jian, ZHENG Yongchao, LIU Shichang, ZHANG Yuyan
Science & Technology Review. 2015, 33 (18): 45-48. ;  doi: 10.3981/j.issn.1000-7857.2015.18.007
Full text: HTML (1 KB)  PDF  (3225 KB)  ( 218 )
Abstract ( 247 )
The SiO2 content of iron ore tailings was 55.88%, the metallogenic geological environment was unique and complex in the study area. The tailings was low-silicon magnet with rich source of iron silicate tailings, mainly composed of quartz, amphibole and plagioclase. To maximize use of iron ore tailings, autoclaved aerated concrete (AAC) samples in the optimized plan were successfully prepared with a bulk density of 588 kg/m3 and compressive strength of 3.99 MPa after the iron ore tailings was milled for 25 min and silica sand for 30 min. The results showed that by analysis of X-ray and reaction mechanism the main mineral phases in the AAC products are 0.9 nm tobermorite, 1.1 nm tobermorite, 1.4 nm tobermorite, and C-S-H hydration products, ferrotschermakite, anhydrite, calcite, dolomite and residual quartz The high strength was obtained because the C-S-H gel as a binder and the tobermorite are cemented into each other.

Deduction of probability distribution of M-C strength parameters by Legendre polynomial

LI Xibing, ZHU Huanzhen, HUANG Tianlang
Science & Technology Review. 2015, 33 (18): 49-55. ;  doi: 10.3981/j.issn.1000-7857.2015.18.008
Full text: HTML (1 KB)  PDF  (1771 KB)  ( 407 )
Abstract ( 289 )
It is a fundamental and important topic to study the probability distribution of M-C strength parameters in reliability analysis of geotechnical engineering. The Legendre polynomial is introduced to infer the probability distribution functions of geotechnical shear strength parameters. With the conventional triaxial test data as the original information, an information basis of internal friction angle, friction coefficient f and cohesion c is constructed based on combination theory and linear regression analysis method. Subsequently, hypothesis testing of the probability distribution functions of sample data is conducted. The optional classical probability distribution types of M-C strength parameters are normal distribution, as verified by limited comparison method. The probability distribution functions of internal friction angle, friction coefficient and cohesion are deduced by Legendre orthogonal polynomial numerical approximation method. The K-S test method is used to compare the results of the presented method and normal distribution. It is shown that the K-S test results of probability distribution functions of M-C shear strength parameters deduced by Legendre polynomial are smaller than those of the normal distribution and can be more close to the actual probability distribution.

Combined application of displacement-related and velocity-related energy dissipation devices in the aseismic design of an irregular building structure

ZHAO Shaowei, CUI Hongna, LI Yuxiang, GAO Hongjian
Science & Technology Review. 2015, 33 (18): 56-61. ;  doi: 10.3981/j.issn.1000-7857.2015.18.009
Full text: HTML (1 KB)  PDF  (3381 KB)  ( 194 )
Abstract ( 263 )
A wasp-waisted and irregular overrun building is in consideration. When a pure frame structure is selected, the torsional period ratio and the inter-story drift do not satisfy the requirements in the standards. In view of the external elevation appearance, the arrangement of shear walls on the front plane is not allowed. And there is no suitable position for laying all steel bracing. After a comparison of various schemes, the seismic control plan is designed by using fluid viscous dampers and buckling-restrained braces. In this paper, a three-dimensional finite element model of the structure is established by the ETABS for the calculations of the uncontrolled structure, the structure installed with fluid viscous damper and the structure installed with fluid viscous damper and buckling-restrained brace by the modal shape decomposition response spectrum method. Then, the comparison and analysis of the dynamic characteristics and the seismic response of the three structures are made. Finally, the time-history analysis is carried out. The results show that the fluid viscous damper and the buckling-restrained brace can all reduce the seismic responses effectively. Besides that, the buckling-restrained braces can control the torsion effectively.

Immunomodulatory effects of Panax ginseng oligopeptide of Jilin Province

HE Lixia, LIU Rui, REN Jinwei, CHEN Qihe, WANG Junbo, ZHANG Zhaofeng, LI Yong
Science & Technology Review. 2015, 33 (18): 62-67. ;  doi: 10.3981/j.issn.1000-7857.2015.18.010
Full text: HTML (1 KB)  PDF  (928 KB)  ( 241 )
Abstract ( 293 )
This paper investigates the immunomodulatory effects of Panax ginseng oligopeptide of Jilin providence. A total of 280 specific pathogen free (SPF) female BALB/c mice are randomly divided into 7 groups: the control group, the whey protein group (whey protein of 150 mg/kg) and five groups of Panax ginseng oligopeptide (GOP) at the doses of 37.5, 75, 150, 300 and 600 mg/kg. After 30 days, seven assays are performed to determine the cell-mediated immunity, the humoral immunity, the macrophage phagocytosis and the natural killer (NK) cell activity in the mice, including the splenic lymphocyte proliferation and the delayed-type hypersensitivity assays (for cell-mediated immunity), the IgM antibody response of spleen to SRBC and serum hemolysin level assays (for humoral immunity), the carbon clearance assay and the phagocytic capacity of peritoneal cavity phagocytes assays (for macrophage phagocytosis) and the NK cell activity assays. The results show that the GOP helps significantly to increase the proliferation response of the splenic lymphocyte to the ConA, the delayed-type hypersensitivity to the SRBC, the IgM antibody response of the spleen to the SRBC, the serum hemolysin level, the 37.5 mg/kg macrophage phagocytosis carbon clearance assay, the phagocytic rate (mg/kg) and the phagocytic index, and the NK cell activity (37.5 mg/kg), and the effects are better than those of the whey protein. In conclusion, the GOP could improve the immune functions in mice, by enhancing the functions of the cell-mediated immunity, the humoral immunity, the macrophage phagocytosis and the NK cell activity.

Effect of Resina Draconis on the efficacy of radiotherapy to Lewis lung carcinoma mice

DAI Rongji, YU Bowen, WANG Ran, DAI Shengping, CHEN Yan, LIN Fankai, MENG Weiwei, DENG Yulin
Science & Technology Review. 2015, 33 (18): 68-71. ;  doi: 10.3981/j.issn.1000-7857.2015.18.011
Full text: HTML (1 KB)  PDF  (1439 KB)  ( 410 )
Abstract ( 230 )
It is confirmed that the Resina Draconis has an anti-radiation effect. In this paper, the Lewis lung carcinoma mice model is established on the C57/BL mice by injecting the Lewis lung carcinoma cell in the right auxillary of the mice. The mice are irradiated by the 4 Gy γ-radiation and treated with the Resina Draconis. Then the tumor growth and metastasis as well as the blood index are examined to study the effect of the Resina Draconis on the efficacy of radiotherapy for the Lewis lung carcinoma mice. The results show that the Resina Draconis has no obvious effect on the tumor weight, the tumor volume and the tumor metastasis. But the Resina Draconis has a significant protective effect on the blood platelet for the radiotherapy-treated Lewis lung carcinoma mice. Therefore, it might be concluded that the Resina Draconis can be used for the radiotherapy treatment of cancer.

Water and salt dynamics of coastal saline soil after seedling transplantation

GE Genbatu, HAO Yuguang, XIN Zhiming, AI Ning, ZHAO Xingkai
Science & Technology Review. 2015, 33 (18): 78-83. ;  doi: 10.3981/j.issn.1000-7857.2015.18.013
Full text: HTML (1 KB)  PDF  (2741 KB)  ( 97 )
Abstract ( 209 )
Soil preparation with cave padded plastic film was implemented to ameliorate saline soil in Nanpu economic development area in Tangshan, Hebei province. In order to provide a theoretical basis for afforestation tree species selection in the coastal saline soil, the objective seedlings including Fraxinus chinensis (Fraxinus velutina Torr), Sophora japonica (Sophora japonica Linn), sabina chinensis (Sabina chinensis) and willow (Salix babylonica) were transplanted and the soil water and salt dynamic changes were continuously monitored for two years to study the effects of seedling transplantation with earth boring auger on the water and salt dynamics of coastal saline soil. It was shown that compared with the control group without transplantation, the soil moisture and electrical conductivity were reduced after seedling transplantation while the range of variation increased and the effect on the trend of soil moisture content and conductivity was not significant; the growing season and crown structure and water uptake by plant roots were the main reasons for changes of water and salt dynamics after seedling transportation, specifically, the effect of the growing season manifested that the differences of soil moisture contents of the seedlings were significant, the crown structure of seedling mainly influenced the soil moisture content of topsoil, and the water uptake by plant roots transformed the vertical distribution of the soil moisture and salic horizon. Among the four seedling species, there was no significant difference in terms of dynamics of soil moisture content, while the soil conductivities varied remarkably. The impact on soil electrical dynamics and salt rejection of sabina chinensis was the largest in the four species.

Investigation of mini-preparation of recombinant adeno-associated virus and its infection in vitro and in vivo

LU Jianqing, MA Hong, SUN Feiyi, DENG Yulin
Science & Technology Review. 2015, 33 (18): 72-77. ;  doi: 10.3981/j.issn.1000-7857.2015.18.012
Full text: HTML (1 KB)  PDF  (11618 KB)  ( 112 )
Abstract ( 311 )
Recombinantadeno-associated virus (rAAV) is a developed vector. The rAAV is used to establish animal models of gene over-expression or knock down and as the tool of gene therapy. We use the three plasmids assay to package the rAAV which carries the EGFP gene in HEK293 cells. Through a series of experiments, we establish the method of rAAV purification. In this method, we lyse the cells using sodium deoxycholate, then remove the hybridproteins by adding high concentration NaCl, and purify the rAAV through heparin affinity column. After concentration by ultrafiltration, the rAAV titer can reach to more than 1013 gene copys /mL. The results of different multiplicity of infection (MOI) and time using rAAV to infect HEK 293 cell show that the best condition of infection is MOI=106 and 3 days. After 3 weeks of injecting rAAV to substantia nigra pars compacta of rat midbrain, there are EGFP expressed in the dopaminergic neurons. We have established a method to prepare small amount rAAV in the lab, which can be used in vitro and in vivo.
Reviews

Immune regulatory function of T cell-inhibitory receptors

WANG Shuaiwei, LUO Xuerui, LI Yangyang, LIN Fang, LI Dan, YUAN Xiaojun, LI Bin
Science & Technology Review. 2015, 33 (18): 84-90. ;  doi: 10.3981/j.issn.1000-7857.2015.18.014
Full text: HTML (1 KB)  PDF  (1720 KB)  ( 1194 )
Abstract ( 328 )
T lymphocytes play a fundamental role in cellular immune and immune regulation in immune system. However, the overactivation of T cells may induce many diseases including asthma, systemic lupus-erythematosus. It is crucial to control the T cell over-activation in the immunotherapy field. The inhibitory receptors of T cells can regulate proliferation and function of T cells by contacting with their ligands. Latest studies have indicated that T cell inhibitory receptors targeting therapy can attenuate the symptoms of diseases and graft rejection. Intensive study on the regulation of T cells would provide effective strategies for preventing and treating immune diseases.

Poolside inspection technology for pressurized water reactor fuel assemblies

REN Liang, LI Guoyun, JIANG Linzhi, ZHANG Xianpeng, KUANG Liuwei, TANG Hongkui, ZHANG Haisheng
Science & Technology Review. 2015, 33 (18): 91-95. ;  doi: 10.3981/j.issn.1000-7857.2015.18.015
Full text: HTML (1 KB)  PDF  (7260 KB)  ( 677 )
Abstract ( 539 )
Fuel assemblies poolside inspection (PSI) is an important test in nuclear power plants. In this paper, PSI technology is introduced, including its principle, inspection contents, and various methods. The research status at home and abroad is summarized. PSI technology usually includes visual inspection, dimension measurement and oxide film measurement. It is an important method for irradiation effect research, and has been successfully used for surface inspection, irradiation growth and oxide layer thickness test of fuel assembly, providing necessary basis for evaluation of irradiation stability and integrity of pressurized water reactor fuel assembly.
Focus

A survey of airworthiness system of EASA CS-E

BAO Mengyao, FAN Fei, ZHAO Yang
Science & Technology Review. 2015, 33 (18): 96-101. ;  doi: 10.3981/j.issn.1000-7857.2015.18.016
Full text: HTML (205 KB)  PDF  (2035 KB)  ( 359 )
Abstract ( 821 )
CS-E is the airworthiness standard of aircraft engine in Europe and it is under constant changing to adapt to new safety demands of airworthiness certification. In this paper, starting from the three level division of aero-engine airworthiness system of European Aviation Safety Agency (EASA), the status and responsibility of CS-E are firstly expounded, and then the logical structure and historical amendments of CS-E are analyzed. In the analysis, the revised regulations in each amendment are particularly focused on and the revised reason of regulation can be generalized into five aspects: development of technology, hazardous accident, overly strict rules or vice versa, unclear definition or explanation, and international uniformity. Thus, this survey provides reference to the development and improvement of airworthiness system in China.
Special Column of Science

Science & Technology Review. 2015, 33 (18): 102-103.
Full text: HTML (175 KB)  PDF  (1737 KB)  ( 330 )
Abstract ( 482 )
Scientists

Science & Technology Review. 2015, 33 (18): 106-106.
Full text: HTML (99 KB)  PDF  (983 KB)  ( 422 )
Abstract ( 662 )

Science & Technology Review. 2015, 33 (18): 110-110.
Full text: HTML (91 KB)  PDF  (899 KB)  ( 82 )
Abstract ( 599 )
Book Reviews

Science & Technology Review. 2015, 33 (18): 107-107.
Full text: HTML (80 KB)  PDF  (790 KB)  ( 128 )
Abstract ( 672 )
Perspectives

Science & Technology Review. 2015, 33 (18): 109-109.
Full text: HTML (103 KB)  PDF  (1024 KB)  ( 107 )
Abstract ( 679 )
Science and Technology Fund

Science & Technology Review. 2015, 33 (18): 111-111.
Full text: HTML (64 KB)  PDF  (632 KB)  ( 250 )
Abstract ( 781 )

Copyright © Editorial office of Science & Technology Review
Tel: +86-10-62138113 Fax: +86-10-62138113 E-mail: jdbbjb@cast.org.cn
京ICP备14028469号-1