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1The application of large volume airgun sources to the onshore-offshore seismic surveys: implication of the experimental results in northern South China Sea显示文摘Onshore-offshore seismic experiments were carried out for the first time in northern South China Sea using large volume airgun sources at sea and seismic stations on land. The experimental results indicate that seismic signals from the new airgun array of R/V Shiyan 2 can be detected as far as 255 km. The signal effective area reaches nearly 50000 km2, which covers Hong Kong and Pearl River Delta. Compared with the old airgun array, the signal amplitude, propagation distance and effective area of the new airgun array have been increased notably, which demonstrates that the upgrade of the airgun source was successful. Comparisons with previous experimental results in other regions show that the shooting effect of the new airgun array is similar to those best airgun sources in the world. Especially, it is a new breakthrough in using the permanent seismic stations onshore to record long distance airgun signals offshore, which has great significance to the realization of the 'seismic radar' concept and the 3D seismic surveys of crustal structure in coastal areas.QIU XueLin CHEN Yong ZHU RiXiang XU HuiLong SHI XiaoBin YE ChunMing ZHAO MingHui XIA ShaoHong 2007Chinese Science Bulletin2007,52,4:27
2Chemical characteristics of PM_(2.5) during haze episodes in the urban of Fuzhou,China显示文摘Atmospheric fine particles(PM_(2.5)) were collected in this study with middle volume samplers in Fuzhou,China,during both normal days and haze days in summer(September 2007) and winter(January 2008).The concentrations,distributions,and sources of polycyclic aromatic hydrocarbons(PAHs),organic carbon(OC),elemental carbon(EC),and water soluble inorganic ions(WSIIs) were determinated.The results showed that the concentrations of PM2.5,PAHs,OC,EC,and WSIIs were in the orders of haze > normal and winter > summer.The dominant PAHs of PM2.5 in Fuzhou were Fluo,Pyr,Chr,BbF,BkF,BaP,BghiP,and IcdP,which represented about 80.0%of the total PAHs during different sampling periods.The BaPeq concentrations of ∑PAHs were 0.78,0.99,1.22,and 2.43 ng/m3 in summer normal,summer haze,winter normal,and winter haze,respectively.Secondary pollutants(SO_4^(2-),NO_3^-,NH_4^+.and OC) were the major chemical compositions of PM2.5,accounting for 69.0%,55.1%,63.4%,and 64.9%of PM2.5 mass in summer normal,summer haze,winter normal,and winter haze,respectively.Correspondingly,secondary organic carbon(SOC) in Fuzhou accounted for 20.1%,48.6%,24.5%,and 50.5%of OC.The average values of nitrogen oxidation ratio(NOR) and sulfur oxidation ratio(SOR) were higher in haze days(0.08 and 0.27) than in normal days(0.05 and 0.22).Higher OC/EC ratios were also found in haze days(5.0) than in normal days(3.3).Correlation analysis demonstrated that visibility had positive correlations with wind speed,and negative correlations with relative humidity and major air pollutants.Overall,the enrichments of PM_(2.5),OC,EC,SO_4^(2-),and NO_3^- promoted haze formation.Furthermore,the diagnostic ratios of IcdP/(IcdP + BghiP),IcdP/BghiP,OC/EC,and NO_3^-/SO_4^(2-) indicated that vehicle exhaust and coal consumption were the main sources of pollutants in Fuzhou.Fuwang Zhang Lingling Xu Jinsheng Chen Xiaoqiu Chen Zhenchuan Niu Tong Lei Chunming Li Jinping Zhao 2013Particuology2013,11,3:19
3Influences of milling and grinding on machined surface roughness and fatigue behavior of GH4169 superalloy workpieces显示文摘Surface topography of superalloy GH4169 workpieces machined by milling and grinding is different significantly. Meanwhile, surface roughness, as one of the main indicators of machined surface integrity, has a great influence on the fatigue behavior of workpieces. Based on analyzing the formation mechanism and characteristics of surface roughness utilizing different machining processes and parameters, the machined surface roughness curve can be decoupled into two parts utilizing frequency spectrum analysis, which are kinematic surface roughness curve and stochastic surface roughness curve. The kinematic surface roughness curve is influenced by machining process,parameters, geometry of the cutting tool or wheel, the maximum height of which is expressed as R'_z.By subtracting the kinematic part from the measurement curve, the stochastic surface roughness curve and its maximum height R''_zcan be obtained, which is influenced by the defects of cutting tool edge or abrasive grains, built-up edges(BUE), cracks, high frequency vibration and so on. On the other hand, the results of decoupling analysis of surface roughness curves indicate that Raand Rz values of milling GH4169 are 2–5 times and 1–3 times as high as those of grinding, while R''_zvalue of milling is 13.85%–37.7% as high as that of grinding. According to the results of fatigue life tests of specimens machined by milling and grinding, it can be concluded that fatigue behavior of GH4169 decreases with the increase of R''_zmonotonically, even utilizing different machining processes.Xun LI Chunming GUAN Peng ZHAO 2018Chinese Journal of Aeronautics2018,31,6:16
4The catalytic behavior of La-Mn-O nanoparticle perovskite-type oxide catalysts for the combustion of the soot particle from the diesel engine显示文摘The La1?xMx MnO3(M=Li, Na, K, Rb, x=0, 0.10, 0.25) perovskite-type oxides whose sizes are nanoparticle have been prepared by the citric acid-ligated method. The characters of the catalysts were characterized by means of XRD, IR, SEM and BET surface area measurement. The catalytic activity for the combustion of soot particulate was evaluated by a technique of the temperature-programmed reaction. In the LaMnO3 catalyst, the partial substitution of alkali metal (Li, Na, K, Rb) into A-site enhanced the catalytic activity for the combustion of soot particle. The La0.75K0.25MnO3 oxides are good candidate catalysts for the soot particle removal reaction, and the combustion tem- peratures of soot particle are between 285℃ and 430℃ when the contact of catalysts and soot is loose, and their catalytic activities for the combustion of soot particle are as good as supported Pt catalysts, which is the best catalyst system so far reported for soot combustion under loose con- tact conditions.WANG Hong ZHAO Zhen XU Chunming LIU Jian LU Zhixiao 2005Chinese Science Bulletin2005,50,14:10
5Rapid genomic changes in polyploid wheat and related species:implications for genome evolution and genetic improvement显示文摘A polyploid organism by possessing more than two sets of chromosomes from one species (autopolyploidy) or two or more species (allopolyploidy) is known to have evolutionary advantages. However, by what means a polyploid accommodates increased genetic dosage or divergent genomes (allopolyploidy) in one cell nucleus and cytoplasm constitutes an enormous challenge. Recent years have witnessed efforts and progress in exploring the possible mechanisms by which these seemingly intangible hurdles of polyploidy may be ameliorated or eventually overcome. In particular, the documentation of rapid and extensive non-Mendelian genetic and epigenetic changes that often accompany nascent polyploidy is revealing: the resulting non-additive and novel gene expression at global, regional and local levels, and timely restoration of meiotic chromosomal behavior towards bivalent pairing and disomic inheritance may ensure rapid establishment and stabilization as well as its long-term evolutionary success. Further elucidation on these novel mechanisms underpinning polyploidy will promote our understanding on fundamental issues in evolutionary biology and in our manipulation capacities in future genetic improvement of important crops that are currently polyploids in genomic constitution. This review is intended to provide an updated discussion on these interesting and important issues within the scope of a specific yet one of the most important plant groups-polyploid wheat and its related species.Bao Liu Chunming Xu Na Zhao Bao Qi Josphert N. Kimatu Jinsong Pang Fangpu Han 2009Journal of Genetics and Genomics2009,36,9:10
6Identification and fine mapping of two blast resistance genes in rice cultivar 93-11显示文摘Rice blast, caused by Magnaporthe oryzae, is a major disease of rice almost worldwide. The Chinese indica cultivar 93-11 is resistant to numerous isolates of the blast fungus in China, and can be used as broad-spectrum resistance resource, particularly in japonica rice breeding programs. In this study, we identified and mapped two blast resistance genes, Pi60(t) and Pi61(t), in cv. 93-11 using F2 and F3 populations derived from a cross between the susceptible cv. Lijiangxintuanheigu(LTH) and resistant cv. 93-11 and inoculated with M. oryzae isolates from different geographic origins. Pi60(t) was delimited to a 274 kb region on the short arm of chromosome 11, flanked by InDel markers K1-4 and E12 and cosegregated with InDel markers B1 and Y10. Pi61(t) was mapped to a 200 kb region on the short arm(near the centromere) of chromosome 12, flanked by InDel markers M2 and S29 and cosegregating with InDel marker M9. In the 274 kb region of Pi60(t), 93-11 contains six NBS-LRR genes including the two Pia/ PiCO39 alleles(BGIOSGA034263 and BGIOSGA035032) which are quite close to the two Pia/ PiCO39 alleles(SasRGA4 and SasRGA5) in Sasanishiki and CO39, with only nine amino acids differing in the protein sequences of BGIOSGA035032 and SasRGA5. In the 200 kb region of Pi61(t), 93-11 contains four NBS-LRR genes, all of which show high identities in protein sequence with their corresponding NBS-LRR alleles in susceptible cv. Nipponbare. Comparison of the response spectra and physical positions between the target genes and other R genes in the same chromosome regions indicated that Pi60(t) could be Pia/PiCO39 or its allele, whereas Pi61(t) appears to be different from Pita, Pita-2, Pi19(t), Pi39(t) and Pi42(t) in the same R gene cluster. DNA markers tightly linked to Pi60(t) and Pi61(t) will enable marker-assisted breeding and map-based cloning.Cailin Lei Kun Hao Yilong Yang Jian Ma Shuai Wang Jiulin Wang Zhijun Cheng Shasha Zhao Xin Zhang Xiuping Guo Chunming Wang Jianmin Wan 2013The Crop Journal2013,1,1:8
7OCEAN BOTTOM SEISMOMETER AND ONSHOREOFFSHORE SEISMIC EXPERIMENT IN NORTHEASTERN SOUTH CHINA SEA显示文摘Three-component Ocean Bottom Seismometers, portable land stations and marine air gun seismic sources were used to carry out an onshore-offshore deep seismic profile in northeastern South China Sea. This profile, orientated in NNW-SSE, was as long as 500 km and perpendicular to the strike of regional tectonics. The offshore data were processed in Taiwan Ocean University using a number of available software and the onshore data were analyzed in South China Sea Institute of Oceanology by new-written programs and public software. Preliminary results show that the seismic data are in good quality and contain rich information of deep structure. Seismic phases, e.g. Pg, PmP and Pn, are identified in the offset range 5~220 kin, which will provide an important dataset for the deep crustal structure and oil-gas basin evolution studies of this region.QIU Xuelin ZHAO Minghui YE Chunming WANG Tankai WANG Ping ZHANG Yixiang XIA Kanyuan LEE Chaoshing 2004Geotectonica et Metallogenia2004,28,1:8
8Separation and characterization of petroleum asphaltene fractions by ESI FT-ICR MS and UV-vis spectrometer显示文摘Using heptane, toluene, and tetrahydrofuran (THF) as eluant, asphaltenes were fractionated into five fractions based on their polarity and solubility. The molecular composition of polar heteroatom species in both asphaltene and its fractions were analyzed by negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS). The application of UV-vis spectrometer in characterizing asphaltene composition and measuring asphaltene concentration was discussed. About 11.9 wt% asphaltene components adsorbed permanently on silica gel in the extrography column after excessive elution with various solvents. In negative FT-ICR MS, the mass spectra show that acidic and neutral nitrogen-containing compounds such as N1 and N1S1 mainly existe in the first three less polar fractions, while oxygen-containing compounds such as O2 , O2S, O2S2 , O3 , and O4 show high relative abundance in more polar fractions. These results suggest oxygen-containing compounds have stronger adsorption ability with silica gel. It was observed that the double bond equivalence (DBE) distribution of N1 class species in the fractions shifted to higher values while the carbon number shifted to smaller numbers as polarity of fractions increased. This indicates that acidic and neutral N1 compounds with longer carbon chain and less aromaticity have less polarity compared with those with shorter carbon chain and stronger aromaticity. UV-vis absorbance indicats that fractions containing the most aromatic and most polar asphaltene have better absorbance at long wavelength, while the fractions that consist of least aromatic and least polar asphatlenes show high absorbance at short wavelength.WANG ShanShan YANG Chuang XU ChunMing ZHAO SuoQi SHI Quan 2013Science China Chemistry2013,56,7:6
9Superior in vitro anticancer effect of biomimetic paclitaxel and triptolide co-delivery system in gastric cancer显示文摘As a well-known anticancer drug,paclitaxel(PTX),a first-line chemotherapeutic agent,remains unsatisfactory for gastric cancer therapy.It is reported that triptolide(TPL)could enhance the anti-gastric cancer effect of PTX.Considering the poor solubility of both drugs,we developed a red blood cell membrane-biomimetic nanosystem,an emerging tool in drug delivery,to co-load paclitaxel and triptolide(red blood cell membrane coated PTX and TPL co-loaded poly(lactic-co-glycolic acid)[PLGA]nanoparticles,RP(P/T)).The successful preparation was confirmed in terms of particle size,morphology,and surface markers assays.This biomimetic system could prolong circulation and escape immune surveillance.And these properties were verified by stability,in vitro drug release,and cellular uptake assays.Moreover,the MTT and colony formation assays demonstrated the superior anti-proliferation effect of the RP(P/T)to free drugs.The enhanced antitumor effects of RP(P/T)on migration and invasion were also evaluated by wound-healing and transwell assays.Overall,the bionic co-delivery nanoplatform with improved efficacy in vitro is a promising therapy for gastric cancer.Siwan Wang Hui Jiang Jia Wang Haisi Wu Ting Wu Mengnan Ni Qianqian Zhao You Ji Ziting Zhang Chunming Tang Huae Xu 2021The Journal of Biomedical Research2021,35,4:5
10The effect of slight to minor biodegradation on C_6 to C_7 light hydrocarbons in crude oils: a case study from Dawanqi Oilfield in the Tarim Basin,NW China显示文摘Light hydrocarbons(LHs) are one of the main petroleum fractions in crude oils, and carry much information regarding the genetic origin and alteration of crude oils. But secondary alterations—especially biodegradation—have a significant effect on the composition of LHs in crude oils. Because most of the LHs affected in oils underwent only slight biodegradation(rank 1 on the biodegradation scale), the variation of LHs can be used to describe more the refined features of biodegradation. Here,23 crude oils from the Dawanqi Oilfield in the Tarim Basin, NW China, eleven of which have been biodegraded to different extents, were analyzed in order to investigate the effect of slight to minor biodegradation on C_6–C_7 LHs.The study results showed that biodegradation resulted in the prior depletion of straight-chained alkanes, followed by branched alkanes. In slight and minor biodegraded oils,such biodegradation scale could not sufficiently affect C_6–C_7cycloalkanes. For branched C_6–C_7 alkanes, generally,monomethylalkanes are biodegraded earlier than dimethylalkanes and trimethylalkanes, which indicates that branched alkanes are more resistant to biodegradation, with the increase of substituted methyl groups on parent rings.The degree of alkylation is one of the primary controlling factors on the biodegradation of C_6–C_7 LHs. There is a particular case: although 2,2,3-trimethylbutane has a relative higher alkylation degree, 2,2-dimethylpentane is more resistant to biodegradation than 2,2,3-trimethylbutane. 2,2-Dimethylpentane is the most resistant to biodegradation in branched C_6–C_7 alkanes. Furthermore, the 2-methylpentane/3-methylpentane and 2-methylhexane/3-methylhexane ratios decreased steadily with increasing biodegradation,which implies that isomers of bilateral methyl groups are more prone to bacterial attack relative to mid-chain isomers. The position of the alkyls on the carbon skeleton is also one of the critical factors controlling the rate of biodegradation. With increasing biodegradation, Mango's LH parameters K1 values decrease and K2 values increase,the values of n-heptane and isoheptane decrease, and the indices of methylcyclohexane and cyclohexane increase.LH parameters should be applied cautiously for the biodegraded oils. Because biodegraded samples belong to slight or minor biodegraded oils, the values of n-heptane and isoheptane from Dawanqi Oilfield can better reflect and determine the ‘‘Biodegraded'' zone. When the heptane value is 0–21 and the isoheptane value is 0–2.6, the crude oil in Dawanqi Oilfield is defined as the ‘‘Biodegraded'' zone.Lu Yang Chunming Zhang Meijun Li Jing Zhao Xuening Qi Jinxiu Du 2016Acta Geochimica2016,35,2:5
11Dual-turbo receiver architecture for turbo coded MIMO-OFDM systems显示文摘This paper presents a novel architecture of iterative receivers with two layers of iterations for turbo coded multiple-input and multiple-output orthogonal frequency-division multiplexing(MIMO-OFDM)systems,where soft messages are passed not only between the MIMO detector and the turbo decoder,but also between the two component decoders within the turbo decoder.We first derive the factor graph representation of a turbo coded system as a basic building block for developing the iterative receivers.Then,a new soft message passing schedule over the factor graph is proposed,resulting in the proposed dual-turbo receiver architecture(DTRA).In DTRA,the MIMO detector and the turbo decoder work concurrently,and the soft messages for both layers of iterations are updated instantaneously,instead of the block-based exchange of soft messages in the conventional iterative receivers.In so doing,the processing latency can be greatly reduced while low computational complexity can be achieved.WANG WenJin GAO XiQi WU XiaoFu YOU XiaoHu ZHAO ChunMing WONG Kai-Kit 2012Science China(Information Sciences)2012,55,2:5
12Characterization of heavy petroleum fraction by positive-ion electrospray ionization FT-ICR mass spectrometry and collision induced dissociation: Bond dissociation behavior and aromatic ring architecture of basic nitrogen compounds显示文摘This paper examined the bond dissociation behavior and aromatic ring architecture of basic nitrogen compounds in Sudan heavy petroleum fraction. Both broadband and quadrupole isolation modes positive-ion electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) coupled with collision induced dissociation (CID) techniques were used to characterize a low sulfur crude oil derived vacuum residuum (VR). The appropriate CID operating condition was selected by comparing the molecular weight distributions of the basic nitrogen compounds under various CID operating conditions. Both oddand even-electron fragment ions were observed from the mass spectrum, indicating that the heterolytic and homolytic bond cleavages occurred simultaneously during the CID process. The odd-electron fragment ions were predominant in each class species, indicating preferential heterolytic bond cleavages. At the optimal CID condition, the alkyl groups decomposed deeply and just left the aromatic cores of the nitrogen compounds. No significant variation in double bond equivalent (DBE) value was observed between the fragment and parent ions, revealing that the domination of single core structure.ZHANG LinZhou ZHANG YaHe ZHAO SuoQi XU ChunMing CHUNG Keng H. SHI Quan 2013Science China Chemistry2013,56,7:5
13Trade Barriers and Participation in the Global Value Chain:An Empirical Study Based on Anti-dumping toward China显示文摘This paper investigates the effects of trade barriers on China s participation in the global value chain(GVC)using a thorough decomposition approach for trade volume,total exports,final exports and intermediate exports.Our econometric results indicate that anti-dumping(AD)measures initiated by trade partners have restrained the process of China s participation in the GVC.From 2000 to 2014,AD measures reduced the foreign value-added rate of total,final and intermediate exports by 4.5 to 28.7 percent,3.4 to 17 percent and 1.2 to 8.5 percent,respectively.In addition,suffering the effects of AD measures,China s GVC position index declined by 8.2 percent to 28.6 percent during this period.Moreover,AD measures have increased industries'upstream index by 3.2 to 13.7 percent over the same period.These results imply that both the petition and approval of AD cases has had a negative influence on the extent and position of China s GVC participation.Xiaosong Wang Zhexi Liu Yue Lv Chunming Zhao 2019China & World Economy2019,27,2:5
14Transmission capacity maximization for LED array-assisted multiuser VLC systems显示文摘In this paper, we present a light-emitting diode(LED) array-assisted visible light communication(VLC) system. Considering the requirements of illumination, the human eye safety, and the energy saving,we optimize the optical power allocation(PA) to maximize the transmission capacity of the overall system.Specifically, we discuss two typical scenarios where the LED array in each room serves multiple users either simultaneously or in a round-robin manner. The problem corresponding to the first case turns out to be nonconvex whose globally optimal solution is hard to obtain. To address this difficult problem, we first adopt the famous gradient projection algorithm to obtain a locally optimal solution, then we employ powerful convex relaxation techniques, and achieve a high-quality solution. While for the round-robin case, we are able to derive an optimal solution in closed form by virtue of Karush-Kuhn-Tucker conditions. Interestingly, the derived closedform solution follows a water-filling pattern with both square root and two-side clipping operations, which differs from the conventional water-filling-like PA in radiofrequency channels. Numerical results depict the performance advantage provided by the proposed PA strategies under various settings.KONG Lei SHEN Hong XU Wei ZHANG Hua ZHAO ChunMing YOU XiaoHu 2015Science China(Information Sciences)2015,58,8:4
15Global perspectives and future research directions for the phytoremediation of heavy metal-contaminated soil:A knowledge mapping analysis from 2001 to 2020显示文摘In total,9,552 documents were extracted from the Web of Science Core Collection and subjected to knowledge mapping and visualization analysis for the field of phytoremediation of HM-contaminated soil(PHMCS)with CiteSpace 5.7 R3 software.The results showed that(1)the number of publications increased linearly over the studied period.The top 10 countries/regions,institutions and authors contributing to this field were exhibited.(2)Keyword co-occurrence cluster analysis revealed a total of 8 clusters,including“Bioremediation,”“Arsenic,”“Biochar,”“Oxidative stress,”“Hyperaccumulation,”“EDTA,”“Arbuscular mycorrhizal fungi,”and“Environmental pollution”clusters(3)In total,334 keyword bursts were obtained,and the 25 strongest,longest duration,and newest keyboard bursts were analyzed in depth.The strongest keyword burst test showed that the hottest keywords could be divided into 7 groups,i.e.,“Plant bioremediation materials,”“HM types,”“Chelating amendments,”“Other improved strategies,”“Bioremediation characteristics,”“Risk assessment,”and“Other.”Almost half of the newest topics had emerged in the past 3 years,including“biochar,”“drought,”“health risk assessment,”“electrokinetic remediation,”“nanoparticle,”and“intercropping.”(4)In total,9 knowledge base clusters were obtained in this study.The studies of Ali et al.(2013),Blaylock et al.(1997),Huang et al.(1997),van der Ent et al.(2013),Salt et al.(1995),and Salt(1998),which had both high frequencies and the strongest burst scores,have had the most profound effects on PHMCS research.Finally,future research directions were proposed.Kehui Liu Xiaojin Guan Chunming Li Keyi Zhao Xiaohua Yang Rongxin Fu Yi Li Fangming Yu 2022Frontiers of Environmental Science & Engineering2022,16,6:4
16Effects of Calcination Temperature on the Acidity and Catalytic Performances of HZSM-5 Zeolite Catalysts for the Catalytic Cracking of n-Butane显示文摘The acidic modulations of a series of HZSM-5 catalysts were successfully made by calcination at different treatment temperatures, i.e. 500, 600, 650, 700 and 800 °C, respectively. The results indicated that the total acid amounts, their density and the amount of B-type acid of HZSM-5 catalysts rapidly decreased, while the amounts of L-type acid had almost no change and thus the ratio of L/B was obviously enhanced with the increase of calcination temperature (excluding 800 °C). The catalytic performances of modified HZSM-5 catalysts for the cracking of n-butane were also investigated. The main properties of these catalysts were characterized by means of XRD. N2 adsorption at low temperature, NH3-TPD, FT- IR of pyridine adsorption and BET surface area measurements. The results showed that HZSM-5 zeolite pretreated at 800 °C had very low catalytic activity for n-butane cracking. In the calcination temperature range of 500-700 °C, the total selectivity to olefins, propylene and butene were increased with the increase of calcination temperature, while, the selectivity for arene decreased with the calcination temperature. The HZSM-5 zeolite calcined at 700 °C produced light olefins with high yield, at the reaction temperature of 650 °C the yields of total olefins and ethylene were 52.8% and 29.4%, respectively. Besides, the more important role is that high calcination temperature treatment improved the duration stability of HZSM-5 zeolites. The effect of calcination temperature on the physico-chemical properties and catalytic performance of HZSM-5 for cracking of n-butane was explored. It was found that the calcination temperature had large effects on the surface area, crystallinity and acid properties of HZSM-5 catalyst, which further affected the catalytic performance for n-butane cracking.Jiangyin Lu Zhen Zhao Chunming Xu Aijun Duan Pu Zhang 2005Journal of Natural Gas Chemistry2005,14,4:3
17Distribution and identification of the low-velocity layer in the northern South China Sea显示文摘低速度的层(LVL ) ,与构造活动和动态背景密切相关,总是是在深外壳的结构研究的一个热话题。深地震(OBS/OBH ) 并且自从 1990 年代,向陆近海的实验广泛地在北华南海(SCS ) 被实现了。六地震侧面被国内、国际的合作在 SCS 的北边缘上完成。外壳的结构的特征被揭示,五速度倒置层被发现。在他们之中,有 3.0-3.5 km · s -1 速度的三 LVL 位于 Yinggehai 盆和珀尔河嘴盆的沉积结构(深入地的 2.0-6.0km 和在厚度的 2.0-4.6 km ) 。他们被反射、折射的阶段为他们的浅深度识别。有 5.5-6.0 km · s -1 速度的另外的二 LVL 通常在东北、西北的 SCS 的过渡外壳的结构与大约 2.5-6.0 km 厚度在中间的外壳(深入地的 7.0-18.0 km ) 中存在。他们被折射阶段检测从他们的覆盖并且内在的层。我们探索了与以前报导的结果结合的可能的构造形成机制,它为 SCS 的形成和进化提供了证据。Zhao Minghui Qiu Xuelin Xu Huilong Shi Xiaobin Wu Shimin Ye Chunming Xia Shaohong 2007Progress in Natural Science:Materials International2007,17,5:3
18Performance evaluation for PCC-OFDM systems impaired by carrier frequency offset over AWGN channels显示文摘Orthogonal frequency division multiplexing (OFDM) is sensitive to carrier frequency offset (CFO), which destroys the orthogonality and causes inter-carrier interference (ICI). ICI self-cancellation schemes based on polynomial cancellation coding (PCC-OFDM) can evidently reduce the sensitivity to CFO. In this paper, we analyze the performance of PCC-OFDM systems impaired by CFO over additive white gaussian noise (AWGN) channels. Two criteria are used to evaluate the effect of CFO on performance degradations. Firstly, the closed-form expressions of the average carrier-to-interference power ratio (CIR) and the statistical average ICI power, both of which reflect the desired power loss, are presented. Simulation and analytical results show that the theoretical expressions depend crucially on the normalized frequency offset and are hardly relevant to the number of subcarriers. Secondly, by exploiting the properties of the Beaulieu series, the effect of CFO on symbol error rate (SER) and bit error rate (BER) performance for PCC-OFDM systems are exactly expressed as the sum of an infinite series in terms of the characteristic function (CHF) of ICI. We consider the systems modulated with binary phase shift keying (BPSK), quadrature PSK (QPSK), 8-ary PSK (8-PSK), and 16-ary quadrature amplitude modulation (16-QAM), and all above modulation schemes are mapped with Gray codes for the evaluations of BER.ZHOU Peng ZHAO ChunMing SHI ZhiHua GONG XiaoQun 2008Science in China(Series F)2008,51,3:3
19Thermal transformation of acid compounds in high TAN crude oil显示文摘The Liaohe crude oil with high total acid number (TAN) was subjected to thermal reaction at 300℃to 500℃. Reaction products were collected and analyzed by negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) to determine acid compounds in the crude oil. The double-bond equivalence (DBE) versus carbon number was used to characterize the oxygenated components in the feed and reaction products. The O2 class which mainly corresponds to naphthenic acids decarboxylated at 350-400℃, resulting in a sharply decrease in TAN. Phenols (O1 class) are more thermally stable than carboxylic acids. Carboxylic acids were also thermally cracked into smaller molecular size acids, evidenced by the presence of acetic acid, propanoic acid, and butyric acid in the liquid product. These small acid species are strong acids likely responsible for corrosion problems in refineries.YANG BaiBing XU ChunMing ZHAO SuoQi HSU Chang Samuel CHUNG Keng H. SHI Quan 2013Science China Chemistry2013,56,7:3
20PVA/PEG Hybrid Hydrogels Prepared by Freeze-thawing and High Energy Electron Beam Irradiation显示文摘ZHAO Chunming LU Xueting HU Qianqian LIU Shuai GUAN Shuang 2017Chemical Research in Chinese Universities2017,33,6:2
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