维普中文期刊产品整合服务
30篇 您的检索式:作者名="CHEN Youxin"
    题名 作者 年代 出处 被引量
1Regional Tectonic Transformation in East Kunlun Orogenic Belt in Early Paleozoic: Constraints from the Geochronology and Geochemistry of Helegangnaren Alkali-feldspar Granite显示文摘The Helegangnaren feldspar granite exposed in the eastern part of East Kunlun, is characterized by high concentrations of SiO2 and alkaline, low abundances of Fe, Mg and Ca, metaluminous-weak peraluminous. Trace elements analysis shows that the granite is depleted extremely in Ba, Sr and Eu, and rich in some large-ion lithophile elements and high field strength elements. Besides, the granite has high Ga contents, the values of 104 (Ga/Al) vary from 2.50 to 2.77, which is mainly greater than the lower limit of A-type granites (2.6), and is higher than the I-and S-type granites' average (2.1 and 2.28, respectively). Rare earth element (REE) is characterized by relatively high fractionations of light REE (LREE) and heavy REE (HREE) (LREE/HREE=9.3-13.60, (La/Yb)N =10.92-18.02), pronounced negative Eu anomalies (δEu=0.08-0.13), and exhibits right-dipping gull pattern. Major elements, rare elements and trace elements features show the granite is ascribed to A-type granite and A2 subtype in tectonic genetic type. They are plotted into post-collision or within-plate area in a variety of tectonic discriminations. Geological and geochemical data comprehensively suggest that the granite is formed in a post-collision extensive tectonic setting. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) zircon U-Pb dating yields a weighted mean age of 425 Ma, belonging to Middle Silurian, which is similar to the age of the post-collision geological events in the region. The differences of magmatic rocks in formation age, rocks assemblage and rocks series systematically indicate that the regional tectonic stress regime in the East Kunlun orogenic belt experienced a major transformation from compress to extension in Middle Silurianin, and the Helegangnaren feldspar granite intruded in the early stage of tectonic transformation.LI Ruibao PEI Xianzhi LI Zhuochen SUN Yu PEI Lei CHEN Guochao CHEN Youxin LIU Chengjun WEI Fanghui 2013Acta Geologica Sinica(English Edition)2013,87,2:35
2Climate and litter C/N ratio constrain soil organic carbon accumulation显示文摘Soil organic carbon(SOC) plays critical roles in stabilizing atmospheric CO2 concentration, but the mechanistic controls on the amount and distribution of SOC on global scales are not well understood. In turn, this has hampered the ability to model global C budgets and to find measures to mitigate climate change. Here, based on the data from a large field survey campaign with 2600 plots across China’s forest ecosystems and a global collection of published data from forested land, we find that a low litter carbon-to-nitrogen ratio(C/N) and high wetness index(P/PET, precipitation-to-potentialevapotranspiration ratio) are the two factors that promote SOC accumulation, with only minor contributions of litter quantity and soil texture. The field survey data demonstrated that high plant diversity decreased litter C/N and thus indirectly promoted SOC accumulation by increasing the litter quality. We conclude that any changes in plant-community composition, plant-species richness and environmental factors that can reduce the litter C/N ratio, or climatic changes that increase wetness index, may promote SOC accumulation. The study provides a guideline for modeling the carbon cycle of various ecosystem scales and formulates the principle for land-based actions for mitigating the rising atmospheric CO2 concentration.Guoyi Zhou Shan Xu Philippe Ciais Stefano Manzoni Jingyun Fang Guirui Yu Xuli Tang Ping Zhou Wantong Wang Junhua Yan Gengxu Wang Keping Ma Shenggong Li Sheng Du Shijie Han Youxin Ma Deqiang Zhang Juxiu Liu Shizhong Liu Guowei Chu Qianmei Zhang Yuelin Li Wenjuan Huang Hai Ren Xiankai Lu Xiuzhi Chen 2019National Science Review2019,6,4:21
3Paleo-Tethyan Oceanic Crust Subduction in the Eastern Section of the East Kunlun Orogenic Belt:Geochronology and Petrogenesis of the Qushi'ang Granodiorite显示文摘The Qushi'ang granodiorite(QSG) is located at the central east of the ophiolitic melange belt in the East Kunlun Orogenic Belt(EKOB) in the northern margin of the Qinghai-Tibetan Plateau. LA-MC-ICP-MS zircon U–Pb dating suggests that the granodiorite and mafic microgranular enclaves(MMEs) crystallized 246.61±0.62 and 245.45±0.9 Ma ago, respectively. Granodiorite, porphyritic diorite, and MMEs are metaluminous and medium-K calk-alkaline series, with island-arc magma features, such as LILE enrichment and HFSE depletion. The porphyritic diorite has high Cr(13.50 ppm to 59.01 ppm), Ni(228.53 ppm to 261.29 ppm), and Mg~#(46–54). Granodiorite and porphyritic diorite have similar mineral compositions and evolved major and trace elements contents, particularly Cr and Ni, both of which are significantly higher than that in granites of the same period. The crystallization age of MMEs is close to that of granodiorite, and their major and trace elements contents are in-between porphyritic diorite and granodiorite. The results suggest that the original mafic magma, which was the product of mantle melting by subduction process, intruded into the lower crust(Kuhai Rock Group), resulting in the formation of granodiorite. Countinous intrusion of mafic magma into the unconsolidated granodiorite formed MMEs and porphyritic diorite. The granodiorite reformed by late-stage strike-slip faulting tectonic event indicates that the strike-slip fault of Middle Kunlun and the collision of the Bayanhar block with East Kunlun were later than 246 Ma. Therefore, the formation of the QSG not only indicates the critical period of evolution of East Kunlun but also represents the tectonic transition from oceanic crust subduction to slab breaking.CHEN Guochao PEI Xianzhi LI Ruibao LI Zuochen LIU Chengjun CHEN Youxin PEI Lei WANG Meng LI Xiaobing 2017Acta Geologica Sinica(English Edition)2017,91,2:14
4Geochemical Features, Age, and Tectonic Significance of the Kekekete Mafic-ultramafic Rocks, East Kunlun Orogen, China显示文摘The Kekekete mafic-ultramafic rocks are exposed in the Kekesha-Kekekete-Dawate area,which are in the eastern part of the East Kunlun Orogenic Belt.It outcrops as tectonic slices intruding tectonically in the Paleoproterozoic Baishahe Group and the Paleozoic Nachitai Group.The Kekekete mafic and ultramafic rocks is located near the central fault in East Kunlun and lithologically mainly consists of serpentinite,augite peridotite,and gabbro.The LA-ICP-MS zircon U-Pb age of the gabbro is 501±7 Ma,indicating that Kekekete mafic-ultramafic rocks formed in the Middle Cambrian.This rock assemblage is relatively poor in SiO2 and(Na2 O+K2 O) but rich in MgO and SFeO.The chondrite-normalized REE patterns of the gabbro dip slightly to the right;the primitive mantle and MORBnormalized spidergrams of trace elements show enrichment of large-ion lithophile elements(Cs,Rb,Ba,etc.) and no differentiation of high field strength elements.The general dominance of E-MORB features and the geochemical characteristics of OIB suggest that the Kekekete mafic-ultramafic rocks formed in an initial oceanic basin with slightly enriched mantle being featured by varying degrees of mixing of N-MORB depleted mantle and a similar-OIB-type source.From a comprehensive study of the previous data,the author believes that the tectonic history of the East Kunlun region was controlled by a geodynamic system of rifting and extension in the late stages of the Neoproterozoic to early stages of the Early Paleozoic and this formed the paleo-oceanic basin or rift system now represented by the ophiolites along the central fault in East Kunlun,the Kekekete mafic-ultramafic rocks and Delisitan ophiolite.LI Ruibao PEI Xianzhi LI Zuochen SUN Yu FENG Jianyong PEI Lei CHEN Guochao LIU Chengjun CHEN Youxin 2013Acta Geologica Sinica(English Edition)2013,87,5:13
5U–Pb Zircon Geochronology and Geochemistry of the Neoproterozoic Liujiaping Group Volcanics in the Northwest Margin of the Yangtze Block:Implications For the Breakup of the Rodinia Supercontinent显示文摘Investigation of the petrogenesis and the origin of zircons from the volcanic rocks of the Liujiaping Group of the back-Longmenshan tectonic belt in the northwest margin of the Yangtze Block is conducted by analysis of U–Pb geochronology and geochemistry. Results show that selected zircons are characterized by internal oscillatory zonings and high Th/U ratios(0.43–1.18), indicating an igneous origin. Geochronological results of LA–ICP–MS U–Pb dating of the Liujiaping Group zircons yield an age of 809 ± 11 Ma(MSWD = 2.2), implying that the volcanic rocks were formed in the Late Neoproterozoic. Geochemical analysis shows that the rocks are calc-alkaline, supersaturated in Al, and metaluminous to weakly peraluminous. Rare-earth elements are present at high concentrations(96.04–265.48 ppm) and show a rightward incline and a moderately negative Eu anomaly, similar to that of continental rift rhyolite. Trace element geochemistry is characterized by evident negative anomalies of Nb, Ta, P, Th, Ti, inter alia, and strong negative anomalies of K, Rb, Sr, et al. We conclude that the Liujiaping Group volcanic rocks resulted from typical continental crust source petrogenesis and were formed in a continental margin setting, which had no relation to subduction, and thus, were the products of partial melting of the lower crust due to crustal thickening caused by active continental margin subduction and arc–continent collision orogeny in the northwestern Yangtze Block and were triggered by the breakup of the Rodinia supercontinent during the Neoproterozoic.LI Zuochen PEI Xianzhi LI Ruibao PEI Lei LIU Chengjun CHEN Youxin XU Tong YANG Jie WEI Bo 2015Acta Geologica Sinica(English Edition)2015,89,4:8
6Magma Mixing and Mingling for Xiangjiananshan Granitic batholith at eastern area of the East Kunlun Orogenic Belt显示文摘The East Kunlun Orogenic Belt(EKOB)in northeast margin of the Qinghai-Tibetan Plateau is an important part of the Central Orogenic System(COS).During the long-time geological evolution,complicatedCHEN Guochao PEI Xianzhi LI Ruibao LI Zuochen LIU Chenjun CHEN Youxin PEI Lei 2017Acta Geologica Sinica(English Edition)2017,91,S1:5
7EBV-Induced Human CD8^+ NKT Cells Synergise CD4^+ NKT Cells Suppressing EBV-Associated Tumours upon Induction of Thl-Bias显示文摘Wei Xiao Li Li Rui Zhou Ruijing Xiao Yujuan Wang Xiang Ji Mengjun Wu Lan Wang Wei Huang Xiaoling Zheng Xinti Tan Lang Chen Tao Xiong Jie Xiong Youxin Jin Jinquan Tan Yuling He 2009Cellular & Molecular Immunology2009,6,5:5
8Geochronology, Geochemistry and Tectonic Setting of the Bairiqiete Granodiorite Intrusion(Rock Mass) from the Buqingshan Tectonic Mélange Belt in the Southern Margin of East Kunlun显示文摘This study focuses on the zircon U–Pb geochronology and geochemistry of the Bairiqiete granodiorite intrusion(rock mass) from the Buqingshan tectonic mélange belt in the southern margin of East Kunlun. The results show that the zircons are characterized by internal oscillatory zoning and high Th/U(0.14–0.80), indicative of an igneous origin. LA–ICP–MS U–Pb dating of zircons from the Bairiqiete granodiorite yielded an age of 439.0 ± 1.9 Ma(MSWD = 0.34), implying that the Bairiqiete granodiorite formed in the early Silurian. Geochemical analyses show that the rocks are medium-K calc-alkaline, relatively high in Al2O3(14.57–18.34 wt%) and metaluminous to weakly peraluminous. Rare-earth elements have low concentrations(45.49–168.31 ppm) and incline rightward with weak negative to weak positive Eu anomalies(δEu = 0.64–1.34). Trace-element geochemistry is characterized by negative anomalies of Nb, Ta, Zr, Hf and Ti and positive anomalies of Rb, Th and Ba. Moreover, the rocks have similar geochemical features with adakites. The Bairiqiete granodiorite appears to have a continental crust source and formed in a subduction-related island-arc setting. The Bairiqiete granodiorite was formed due to partial melting of the lower crust and suggests subduction in the Buqingshan area of the Proto-Tethys Ocean.LI Zuochen PEI Xianzhi LI Ruibao PEI Lei LIU Chengjun CHEN Youxin LIU Zhanqing CHEN Guochao XU Tong YANG Jie WEI Bo 2014Acta Geologica Sinica(English Edition)2014,88,2:5
9Primary resistance to crizotinib treatment in a non-small cell lung cancer patient with an EML4-ALK rearrangement:a case report显示文摘Crizotinib,a small molecular tyrosine kinase inhibitor,manifests dramatic responses in patients with non-small cell lung cancer with echinoderm microtubule associated protein like 4-anaplastic lymphoma kinase(EML4-ALK)rearrangements.ALK gene point mutation is the primary mechanism of acquired crizotinib resistance;however,the intrinsic mechanism is not fully understood.Here,we report a patient with a low mutant allele fraction(MAF)of EML4-ALK rearrangement,who experienced primary resistance to crizotinib treatment.The patient was a 66-year-old Chinese man,who had a history of metastatic lung cancer and was treated with first-and third-generation epidermal growth factor receptor tyrosine kinase inhibitors(EGFR TKIs).After 14 months of osimertinib treatment,his disease progressed,and next-generation sequencing was performed from a liquid biopsy of the patient’s blood.An EML4-ALK rearrangement was found and crizotinib was administered.The patient’s lung lesions continued to progress after one month of crizotinib treatment,and pemetrexed-bevacizumab was initiated.After two cycles of chemotherapy,the metastatic cancers shrunk,and the patient maintained stable disease at his last follow-up.EML4-ALK rearrangements can happen in patients with EGFR-positive NSCLC,after acquired resistance to EGFR TKI treatment.The EGFR T790M and C797G mutations occur in cis is a critical mechanism of resistance to osimertinib therapy.The MAF of EML4-ALK rearrangements in cancer cells might be a predictive factor for crizotinib treatment.Ling Zhang Yunxia Li Shaohong Zhang Chen Gao Keke Nie Youxin Ji 2018Cancer Biology & Medicine2018,15,2:5
10Mining rice new germplasm containing S_5~n gene by functional molecular marker and sequencing显示文摘Inter-subspecific hybrids between indica and japonica varieties yield strong biological heterosis, but it is difficult to utilize the hybrids directly in commercial production due to sterility of F1. A special gene S5n may overcome the hybrids sterility, which is caused by the interaction between S5 loci. Recently, S5n had been cloned, and it was revealed containing a large DNA deletion sequence that made the gene nonfunctional, compared to S5i or S5j. We designed a pair of primers flanking the deletion sequence of S5n, and then applied to distinguish the varieties with S5n or non-S5n, convincing result suggested that the primers could be served as functional molecular marker to efficiently identify the new germplasm with S5n. Using the functional marker, we surveyed 197 varieties from China National Micro-core Rice Collection, and found ten of which represented S5n including following varieties: Haobuka, Sanbangqishiluo, Mubanggu, Xiaohonggu, Mowanggu’neiza, Laozaogu, Fanhaopi, Feie’nuo2, Baoxie-7B, Teqingxuanhui. Among them, two varieties Sanbangqishiluo and Laozaogu was previously reported to contain S5n gene. Further sequence analysis on the DNA sequence covering both sides of deletion in S5n of the 10 varieties confirmed that the detected sequences in above varieties was identical with those of varieties containing S5n, such as 02428 and Linglun. These results suggested that the gene in S5 locus of the ten varieties was also nonfunctional and it proved the presence of S5n gene.YANG YouXin WU JinWen CHEN ZhiXiong WANG Lan LI JinQuan LIU XiangDong LU YongGen 2009Chinese Science Bulletin2009,54,18:5
11Late Cambrian SSZ-type Ophiolites in Acite Zone, East Kunlun Orogen of Northern Tibet Plateau: Insights from Zircon U-Pb Isotopes and Geochemistry of Oceanic Crust Rocks显示文摘1 Introduction East Kunlun orogen(EKO)stretching more than 1000km in E-W extension is located in the western segment of Central Orogen Belt(COB),China(Xu et al.,2006,Li et al.,2014).There outcropped CambrianLI Ruibao PEI Xianzhi LI Zuochen PEI Lei CHEN Guochao CHEN Youxin LIU Chengjun 2017Acta Geologica Sinica(English Edition)2017,91,S1:3
12Discovery of Early Paleozoic Garnet Amphibolite in the Wenquan Complex,Northern Margin of the Yili Block,NW China显示文摘Objective High-pressure(HP)and ultrahigh-pressure(UHP)minerals tend to be preserved in mafic and ultramafic metamorphic rocks(e.g.eclogites and garnet amphibolite)rather than felsic rocks.Generally,HP and UHP rocks are thought to be formed as a result of the tectonic burial or subduction of oceanic crust or thicked continental lithosphere to depths corresponding to the eclogite facies metamorphism,followed by fast uplift(Ernst et al.,2007).CHEN Youxin CHENG Kaikai PEI Xianzhi WANG Meng ZHAO Shaowei LI Zuochen LI Ruibao PEI Lei GAO feng 2021Acta Geologica Sinica(English Edition)2021,95,2:3
13Molecular evolution of rice S_5~n and functional comparison among different sequences显示文摘The wide compatibility gene, S 5 n , can overcome embryo sac sterility between indica and japonica subspecies of rice. Therefore, it is very important to characterize the features of the S 5 n sequence to reveal the origin and evolution of S 5 n . In this paper, 26 cultivated rice haplotypes and 22 wild rice accessions harboring S 5 n were used to sequence S 5 n . The results showed that 15 genotypes among the 48 materials were fully consistent with control cultivar 02428 (CK). The other 33 accessions had different degrees of variation in the S 5 n sequence. Variations in the coding region mainly occurred in the second exon and eight materials showed a 10-bp deletion at 1710–1719 bp, including wild (O. nivara) and cultivated rice, such as IRW501 and Yuetai B. S 5 n sequences were not biased and evolved neutrally. The 48 materials could be divided into 4 categories using a phylogenetic tree of the amino acid sequences. Most of the wild rice clustered together, and the cultivated rice clustered into another group. Eight cultivated rice and O. nivara (wild rice) clustered in another group, which were found to lack 10 consecutive bases in exon 2. Eight rice varieties with high numbers of differences in their S 5 n coding regions were crossed with testers (typically indica and japonica) to produced test cross F 1 populations. The F 1 s were examined for their ability to overcome indica-japonica hybrid sterility. The result showed that the embryo sac fertility of S 5 n -containing hybrids increased significantly compared with control hybrids, but there were no differences among the materials with divergent sequences, indirectly proving that S 5 n is a non-functional gene.TONG JingFei LI YanHong YANG YouXin SHAHID Muhammad Qasim CHEN ZhiXiong WANG Lan LI JinQuan LIU XiangDong LU YongGen 2011Chinese Science Bulletin2011,56,19:2
14Application of stem cell-derived retinal pigmented epithelium in retinal degenerative diseases: present and future显示文摘As a constituent of blood-retinal barrier and retinal outer segment(ROS) scavenger, retinal pigmented epithelium(RPE) is fundamental to normal function of retina. Malfunctioning of RPE contributes to the onset and advance of retinal degenerative diseases. Up to date, RPE replacement therapy is the only possible method to completely reverse retinal degeneration. Transplantation of human RPE stem cell-derived RPE(h RPESC-RPE) has shown some good results in animal models. With promising results in terms of safety and visual improvement, human embryonic stem cell-derived RPE(h ESC-RPE) can be expected in clinical settings in the near future. Despite twists and turns, induced pluripotent stem cell-derived RPE(i PSC-RPE) is now being intensely investigated to overcome genetic and epigenetic instability. By far, only one patient has received i PSCRPE transplant, which is a hallmark of i PSC technology development. During follow-up, no major complications such as immunogenicity or tumorigenesis have been observed. Future trials should keep focusing on the safety of stem cell-derived RPE(SC-RPE) especially in long period, and better understanding of the nature of stem cell and the molecular events in the process to generate SC-RPE is necessary to the prosperity of SC-RPE clinical application.Mingyue Luo Youxin Chen 2018International Journal of Ophthalmology(English edition)2018,11,1:2
15Non-equal-interval direct optimizing Verhulst model that x(n) be taken as initial value and its application显示文摘To overcome the deficiencies of the existing Verhulst GM(1,1) model, based on the existing grey theory, a non-equal-interval direct optimum Verhulst GM(1,1) model is built which chooses a modified n-th component x(n) of X(0) as the starting condition of the grey differential model. It optimizes a modified β value and the background value, and takes two times fitting optimization. The new model extends equal intervals to non-equal-intervals and is suitable for general data modelling and estimating parameters of the direct Verhulst GM(1,1). The new model does not need to pre-process the primitive data, nor accumulate generating operation (AGO) and inverse accumulated generating operation (IAGO). It is not only suitable for equal interval data modelling, but also for non-equal interval data modelling. As the new information is fully used and two times fitting optimization is taken, the fitting accuracy is the highest in all existing models. The example shows that the new model is simple and practical. The new model is worth expanding on and applying in data processing or on-line monitoring for tests, social sciences and other engineering sciences.Luo, Youxin Chen, Mianyun Che, Xiaoyi He, Zheming 2008Journal of Southeast University(English Edition)2008,24,S1:2
16MiR-200a is involved in rat epididymal development by targeting β-catenin mRNA显示文摘在到成年人的从出生后的开发的老鼠的 epididymis 的 350 microRNAs (miRNAs ) 的表达式(从出生后的天 770 ) 与自制 miRNA microarray 被介绍。在他们之中, 48 miRNAs 显著地变化了,在哪个 miR-200a 的表示与时间显然增加了,在与从北污点分析获得了那的一个好协议。即时量聚合酶的链反应结果显示老鼠 -catenin 的那时间的表情确切在老鼠 epididymal 开发期间是到 miR-200a 的 inversed,暗示 miR-200a 可能也指向在由 Saydam 等报导了的老鼠 epididymis 的 -catenin mRNA。在人。生物信息的分析显示老鼠 -catenin mRNA 的 3 untranslated 区域确实为 miR-200a 包含了一个通常认为的有约束力的地点。同时,这个有约束力的地点的顺序与有二邻近的核苷酸(U 和 C ) 的删除的人的 -catenin mRNA 的不同,这被发现。但是在老鼠 NRK 房间在 HEK 293T 房间和 miR-200a 的 overexpression 指向试金的酶的结果证明 miR-200a 确实指向了老鼠 -catenin mRNA 并且引起它的表示的抑制。所有这些结果证明 miR-200a 应该被指向老鼠的 -catenin mRNA 并且压制它的表达式涉及老鼠 epididymal 开发。Xiaojiang Wu Botao Zhao Wei Li Yue Chen Ruqiang Liang Lin Li Youxin Jin Kangcheng Ruan 2012Acta Biochimica et Biophysica Sinica2012,44,3:2
17Evolution of Financial Risks in Emerging Markets under the Background of an Interest Rate Hike in the US显示文摘In 2018,advanced economies saw continuous recovery and a tightening of monetary policy;however,emerging markets were in for a more challenging year.Since April 2018,financial turmoil in emerging markets has been exacerbated by a faster-than-expected increase in the USD index,a surge for 10-year U.S.treasury yields.A financial crisis broke out first in Argentina,followed by emerging economies like Turkey,Brazil,and Indonesia,substantially exacerbating their financial fragility.What is the commonality between the current round of financial turmoil in emerging markets and historically financial crisis?CHEN Weidong ZHONG Hong WANG Youxin ZHAO Xueqing 2019China Economic Transition2019,2,1:1
18Uterine artery chemoembolization plus 5 - fluorouracil local injections of application in the treatment of cervical pregnancy 显示文摘Yong Hu Youxin Wang Chunhua Chen 2009Chinese Journal of Family Planning2009,17,12:1
19Research on Kiln Body Health Monitoring of Ceramic Roller Kiln with Oxygen-Enriched and Pure Oxygen Combustion显示文摘Xiao Chun Chen Jing Yuan Youxin 2008IEEE Wu han2008,2,:1
20Use of FK506 and bone marrow mesenchymal stem cells for rat hind limb allografts显示文摘Youxin Song Zhujun Wang Zhixue Wang Hong Zhang Xiaohui Li Bin Chen 2012Neural Regeneration Research2012,7,34:1
返回顶部 每页显示:
共2页 首页 上一页 第1页 下一页 末页 /2 跳转

网站首页 | 关于我们 | 联系我们 | 产品服务 | 客服中心 | 广告服务 | 版权声明 | 网站联盟 | 友情链接 | 售卡网点

版权所有© 渝B2-20050021-1 渝公网安备 50019002500403号 违法和不良信息举报中心

互联网出版许可证 新出网证(渝)字10号 全国400电话 - 免长途话费