检索结果-南通市图书馆

Road to Great Power in Telecom

在线全文

学校读者我要写书评

暂无评论

ZTE Communications 2004年第1期2卷 2-5页

作者： Chen Jinqiao (china academy of telecommunications research of mii,Beijing 100083,china)

Chinese telecom industry is experiencing the transition from a large-scale market to a giant with powerful telecom services and *** from the successful experiences of Japan,South Korea and Germany,china may find a proper solution to problems existing in the development of its telecom *** solution can be defined as predetermined strategies,governmental guidance and coordination between enterprises.

关键词： Road to Great Power in Telecom

Development Barriers and Cut-in Points of Next Generation Services

在线全文

学校读者我要写书评

暂无评论

ZTE Communications 2004年第1期2卷 45-47页

作者： Lei Zhenzhou (china academy of telecommunications research of mii,Beijing 100083,china)

The paper discusses the characteristics of next generation services, and analyzes its development barriers and cut-in *** services that NGN offers have to transit from an unknown state to an popular state to become a ... 详细信息

关键词： will In Development Barriers and Cut-in Points of Next Generation Services

IPTV——Beginning of Triple Play

在线全文

学校读者我要写书评

暂无评论

ZTE Communications 2006年第3期4卷 1-5页

作者： Jiang Lintao (china academy of telecommunications research of mii, Beijing 100083, china)

IPTV is directly related to the current 3 operational networks (the cable TV network, Internet and telecom network) and the services they offer. However, different network operators have different expectations of IPTV. For telecom operators, IPTV organizes and transports TV programs over IP networks; while for cable TV operators, IPTV provides digital TV programs and other information services through cable TV networks. IPTV is broadly categorized into broadcast services and interactive services, which are carried respectively by the unidirectional broadcast network and the bidirectional interactive network. Therefore, convergence of the bearer networks is hard to implement. Instead, the convergence will occur on the service layer, so as to make full use of the two existing bearer networks to develop services cost-effectively. IPTV is capable of delivering broadcast, multicast as well as interactive services. It is expected to be the beginning of triple play.

关键词： IPTV NVOD

Updated Development of MS Standardization

在线全文

学校读者我要写书评

暂无评论

ZTE Communications 2007年第1期5卷 13-16页

作者： Li Haihua(china academy of telecommunications research, mii, Beijing 100045, china)

As the integrated core network for fixed and mobile access, the IP Multimedia Subsystem (IMS) adopts the mechanism that separates bear control from session control, as well as separates service control from session control, which greatly enhances the network capabilities. It’s publicly regarded that IMS is the orientation of network evolvement and development nowadays. The international series of IMS standardizations are accomplished by the Third Generation Partnership Project (3GPP) and telecommunications and Internet Converged Services and Protocols for Advanced Networking (TISPAN) standard organizations. This article covers the general standards of IMS by 3GPP and TISPAN, the research on the key technologies and hot issues of IMS. This includes the improvement and enhancement of core control part of IMS network, the existing problems in the interconnection and coexistence between IMS and Circuit Switching (CS) domain that are related to IMS. In addition, it includes the related research upon IMS in the Next Generation Network (NGN) R2 phase.

关键词： IMS IP GPP CSCF

Surface Nanocrystallization of Commercial Pure Titanium Induced by SMAT and Its Properties

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2004年第6期20卷 716-718页

作者： Shulan zhang, Huaining CHEN and Quanhong LINInstitute of Metai research, Chinese academy of Sciences, Shenyang 110016, china Inst. of Metal Res. Chinese Acad. of Sci. Shenyang 110016 China

In this paper the preparation technique of surface nanocrystallization in commercial pure titanium was carried out by surface mechanical attrition treatment (SMAT). The mean grain size was calculated by using X-ray diffraction (XRD) and transmission electron microscope (TEM), and the results showed that the mean grain size of the surface was refined to nm Ievel after SMAT treatment. Nanocrystallized surface layers were formed after treated for 5, 15, 30 and 60 min. Microhardness experimental results implied the microhardness obviously increased on the surface layer and it also showed the variation of microhardness at the cross section. Corrosion test results showed the corrosion resistance of the surfaces in the original commercial pure titanium treated by SMAT was not improved in HCI solution. The corrosion micrographs were observed by scanning electron microscope (SEM).

关键词： Surface nanocrystallization Pure Ti Corrosion

Selenate oxyanion-intercalated NiFeOOH for stable water oxidation via lattice oxygen oxidation mechanism

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2025年第2期101卷 676-684页

作者： Yijie zhang Weiyi zhang Xiaowen zhang Jinping Li Guang Liu Shanxi Key Laboratory of Gas Energy Efficient and Clean Utilization College of Chemical Engineering and Technology Taiyuan University of Technology Shanxi research Institute of Huai Rou Laboratory

Transition metal-based compounds can serve as pre-catalysts to obtain genuine oxygen evolution reaction（OER） electrocatalysts in the form of oxyhydroxides through electrochemical ***,the role and existence form of leached oxygen anions are still ***,we selected iron selenite-wrapped hydrated nickel molybdate（denoted as NiMoO/FeSeO） as a pre-catalyst to study the oxyanion *** is surprising to find that SeO2-exists in the catalyst in the form of intercalation,which is different from previous studies that suggest that anions are doped with residual elements after electrochemical activation,or adsorbed on the catalyst *** experiment and theoretical calculations show that the existence of SeO42-intercalation effectively adjusts the electronic structure of NiFeOOH,promotes intramolecular electron transfer and O-O release,and thus lowers the reaction energy *** expected,the synthesized NiFeOOH-SeO only needs 202 and 285 mV to attain 100 and 1000 mA cm-2in 1 M ***,the anion exchange membrane water electrolyzer（AEMWE） consisting of NiFeOOHSeO anode and Pt/C cathode can reach 1 A cm-2at 1.70 V and no significant attenuation within 300 *** findings provide insights into the mechanism,by which the intercalated oxyanions enhance the OER performance of NiFeOOH,thereby facilitating large-scale hydrogen production through AEMWE.

关键词： Anion exchange membrane electrolyzer Industrial current densities Lattice oxygen oxidation Oxyanion intercalation Water splitting

The Evolution Trend of Optical Core Network

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

china Communications 2008年第1期5卷 4-8页

作者： Mao Qian Wuhan research Institute of Posts and telecommunications,Hubei, Wuhan, 430074 china Wuhan research Institute of Posts and telecommunications Hubei Wuhan 430074 China

Optical network is the infrastructure of telecommunicationnetwork. More than 95% of information istransported over optical network in china, wherecore network is the main trunk. How to increase thebit rate of the single wavelength channel, raise thetotal capacity of the DWDM system, extend theoptical transportation distance of electrical repeaterfree of the DWDM system and optical network intelligenceare key problems demanding high *** evolution trend of the optical core network isdescribed with some examples in this paper.

关键词： optical core network DWDM UHS ULC ULH ASON

How sediment dredging alters phosphorus dynamics in a lowland rural river?

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2025年第1期147卷 189-199页

作者： Qimou zhang Jiacong Huang Yulai Ji Jing zhang Shuai zhang Junfeng Gao Key Laboratory of Watershed Geographic Sciences Nanjing Institute of Geography and LimnologyChinese Academy of SciencesNanjing 210008China University of Chinese academy of Sciences Beijing 10094China

china’s lowland rural rivers are facing severe eutrophication problems due to excessive phosphorus(P)from anthropogenic ***,quantifying P dynamics in a lowland rural river is challenging due to its complex interaction with surrounding areas.A P dynamic model(River-P)was specifically designed for lowland rural rivers to address this *** modelwas coupled with the Environmental Fluid Dynamics Code(EFDC)and the Phosphorus Dynamic Model for lowland Polder systems(PDP)to characterize P dynamics under the impact of dredging in a lowland rural *** on a two-year(2020-2021)dataset from a representative lowland rural river in the Lake Taihu Basin,china,the coupled model was calibrated and achieved a model performance(R^(2)>0.59,RMSEresearch in the study river revealed that(1)the time scale for the effectiveness of sediment dredging for P control was~300 days,with an increase in P retention capacity by 74.8 kg/year and a decrease in TP concentrations of 23%after dredging.(2)Dredging significantly reduced P release from sediment by 98%,while increased P resuspension and settling capacities by 16%and 46%,respectively.(3)The sediment-water interface(SWI)plays a critical role in P transfer within the river,as resuspension accounts for 16%of TP imports,and settling accounts for 47%of TP *** the large P retention capacity of lowland rural rivers,drainage ditches and ponds with macrophytes are promising approaches to enhance P retention *** study provides valuable insights for local environmental departments,allowing a comprehensive understanding of P dynamics in lowland rural *** enable the evaluation of the efficacy of sediment dredging in P control and the implementation of corresponding P control measures.

关键词： Lowland rural river Phosphorus Sediment dredging Model ensemble Retention capacity

Analyzing carbon emissions and influencing factors in Chengdu-Chongqing urban agglomeration counties

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2025年第5期151卷 640-651页

作者： zhang Heng Lu Wenfu Peng Lindan zhang Key Laboratory of the Evaluation and Monitoring of Southwest Land Resources(Ministry of Education) Sichuan Normal UniversityChengdu 610068China The Institute of Geography and Resources Science Sichuan Normal UniversityChengdu 610068China

Majority of carbon emissions originate from fossil energy consumption,thus necessitating calculation and monitoring of carbon emissions from energy *** this study,we utilized energy consumption data from Sichuan Province and Chongqing Municipality for the years 2000 to 2019 to estimate their statistical carbon *** then employed nighttime light data to downscale and infer the spatial distribution of carbon emissions at the county level within the Chengdu-Chongqing urban ***,we analyzed the spatial pattern of carbon emissions at the county level using the coefficient of variation and spatial autocorrelation,and we used the Geographically and Temporally Weighted Regression(GTWR)model to analyze the influencing factors of carbon emissions at this *** results of this study are as follows:(1)from 2000 to 2019,the overall carbon emissions in the Chengdu-Chongqing urban agglomeration showed an increasing trend followed by a decrease,with an average annual growth rate of 4.24%.However,in recent years,it has stabilized,and 2012 was the peak year for carbon emissions in the Chengdu-Chongqing urban agglomeration;(2)carbon emissions exhibited significant spatial clustering,with high-high clustering observed in the core urban areas of Chengdu and Chongqing and low-low clustering in the southern counties of the Chengdu-Chongqing urban agglomeration;(3)factors such as GDP,population(Pop),urbanization rate(Ur),and industrialization structure(Ic)all showed a significant influence on carbon emissions;(4)the spatial heterogeneity of each influencing factor was evident.

关键词： Carbon emissions Chengdu-Chongqing urban agglomeration Spatial autocorrelation Geographically and temporally weighted regression