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| 1 | Active tectonic blocks and strong earthquakes in the continent of China显示文摘The primary pattern of the late Cenozoic to the present tectonic deformation of China is characterized by relative movements and interactions of tectonic blocks. Active tectonic blocks are geological units that have been separated from each other by active tectonic zones. Boundaries between blocks are the highest gradient of differential movement. Most of tectonic activity occurs on boundaries of the blocks. Earthquakes are results of abrupt releases of accumulated strain energy that reaches the threshold of strength of the earth's crust. Boundaries of tectonic blocks are the locations of most discontinuous deformation and highest gradient of stress accumulation, thus are the most likely places for strain energy accumulation and releases, and in turn, devastating earthquakes. Almost all earthquakes of magnitude greater than 8 and 80%-90% of earthquakes of magnitude over 7 occur along boundaries of active tectonic blocks. This fact indicates that differential movements and interactions of active tectonic blocks are the primary mechanism for the occurrences of devastating earthquakes. | ZHANG Peizhen (张培震) DENG Qidong (邓起东) ZHANG Guomin (张国民) MA Jin (马 瑾) GAN Weijun (甘卫军) MIN Wei (闵 伟) MAO Fengying (毛凤英) WANG Qi (王 琪) | 2003 | Science China Earth Sciences2003，46，z2： | 239 |
| 2 | Paleoearthquake rupture behavior and recurrence of great earthquakes along the Haiyuan fault, northwestern China显示文摘The Haiyuan fault is a major seismogenic fault in north-central China where the 1920 Haiyuan earthquake of magnitude 8.5 occurred, resulting in more than 220000 deaths. The fault zone can be divided into three segments based on their geometric patterns and associated geomorphology. To study paleoseismology and recurrent history of devastating earthquakes along the fault, we dug 17 trenches along different segments of the fault zone. Although only 10 of them allow the paleoearthquake event to be dated, together with the 8 trenches dug previously they still provide adequate information that enables us to capture major paleoearthquakes oc- curring along the fault during the past geological time. We discovered 3 events along the eastern segment during the past 14000 a, 7 events along the middle segment during the past 9000 a, and 6 events along the western segment during the past 10000 a. These events clearly depict two temporal clusters. The first cluster occurs from 4600 to 6400 a, and the second occurs from 1000 to 2800 a, approximately. Each cluster lasts about 2000 a. Time period between these two clus- ters is also about 2000 a. Based on fault geometry, segmentation pattern, and paleoearthquake events along the Haiyuan fault we can identify three scales of earthquake rupture: rupture of one segment, cascade rupture of two segments, and cascade rupture of entire fault (three segments). Interactions of slip patches on the surface of the fault may cause rupture on one patch or ruptures of more than two to three patchs to form the complex patterns of cascade rupture events. | ZHANG Peizhen MIN Wei DENG Qidong MAO Fengying | 2005 | Science China Earth Sciences2005，48，3： | 31 |
| 3 | Far-field coseismic displacements associated with the 2011 Tohoku-oki earthquake in Japan observed by Global Positioning System显示文摘Analysis of GEONET observations covering the entire territory of Japan shows that the great Tohoku-oki earthquake that occurred on March 11, 2011 off the east coast of Honshu in Japan caused an eastward movement of the northern part of the island by as much as 5.3 m. The GPS data from TEONET in China were used to derive far-field coseismic displacements and to assess the impact of the Tohoku-oki earthquake on crustal deformation in eastern China. The results reveal that the coseismic horizontal displacements induced by the earthquake are the level of millimeters to centimeters in North and Northeast China, with a maximum of 35 mm. Strain analysis also indicates that the earthquake resulted in an increase in the tensile strain on the north-northeast trending faults in North and Northeast China. The tensile strain imposed on the Yilan-Yitong and Dunhua-Mishan faults is more significant than that imposed on the faults in North China; the maximum normal strain reaches about 40 nano-strain. Considering that the static Coulomb stress loaded on the faults is limited, its effect on the regional seismic activity may not be significant. | WANG Min LI Qiang WANG Fan ZHANG Rui WANG YanZhao SHI HongBo ZHANG PeiZhen SHEN ZhengKang | 2011 | Chinese Science Bulletin2011，56，23： | 34 |
| 4 | Late Cenozoic deformation subsequence in northeastern margin of Tibet --Detrital AFT records from Linxia Basin显示文摘Two events of Tibet uplifting are revealed by detrital apatite fission track (AFT) age data from Linxia Basin. They occurred at about 14 and 5.4-8.0 MaBP respectively. We interpret the first one to be related to the uplifting of the northern Tibet, which might have resulted from convectively removing the thickened lower lithosphere. The second one is a result of Laji Mountain uplifting. Numerous studies of the Tibetan Plateau suggest that the onset time of the deformation in the northeastern margin of Tibetan Plateau and the time of Tibet attaining to its present elevation is about 8 MaBP. They are approximately coincident with the uplift of Lajishan Mountain. It suggests that the northeastern margin of Tibet propagated northeastwardly to its present site in about 8 MaBP for accommodating the sustained convergence between India-Eurasia plate and for keeping its high elevation. The active block pattern dominating the strong earthquake distribution of Chinese continent probably formed at about 8.0-5.4 MaBP. | ZHENG Dewen (郑德文) ZHANG Peizhen (张培震) WAN Jinglin (万景林) LI Chuanyou (李传友) CAO Jixiu (曹继秀) | 2003 | Science China Earth Sciences2003，46，z2： | 25 |
| 5 | Pattern and timing of late Cenozoic rapid exhumation and uplift of the Helan Mountain,China显示文摘The Helan Mountain, an intraplate deformation belt in the North China Craton, is located in the northern portion of the China North-South seismic belt, and at the northwestern margin of the Ordos Block. The Cenozoic deformation history of the Helan Mountain is characterized by extension along the eastern Helan Mountain fault (EHSF), resulting in the exhumation and uplift of the Helan Mountain, relative to the rifting of the adjacent Yinchuan Basin. Here we present new apatite fission track (AFT) data from several transects adjacent to the EHSF in the central and northern Helan Mountain. AFT ages from the northern Helan Mountain (Dawukou and Zhengyiguan transects) range from 10 Ma to 89 Ma, whereas AFT ages from the southern Helan Mountain (Suyukou transect) are greater than 71 Ma. The AFT data analysis reveals initiation of rapid uplift and exhumation of the Helan Mountain at 10–12 Ma. Additionally, a plot of the AFT ages versus their mean track length shows a distinctive 'boomerang' pattern indicating that the Helan Mountain experienced a discrete phase of accelerated exhumation beginning at 10-12 Ma. Spatially, AFT samples systematically increase in age away from the EHSF and are consistent with late Cenozoic exhumation that was slow in the southwestern Helan Mountain and rapid in the northeastern Helan Mountain, as well more rapid adjacent to the EHSF and slower away from the EHSF. Obviously, the spatial distribution of late Cenozoic exhumation indicates that normal faulting of the EHSF is related to southwestward tilting and rapid exhumation of the Helan Mountain beginning at 10–12 Ma. The uplift and exhumation of the Helan Mountain was a response to the intensive extension of the northwestern margin of the Ordos Block in the late Cenozoic; this occurred under a regional extensional stress field oriented NW-SE along the Yinchuan-Jilantai-Hetao and the Weihe-Shanxi graben systems adjacent to the Ordos Block. | LIU JianHui ZHANG PeiZhen ZHENG DeWen WAN JinLin WANG WeiTao DU Peng LEI QiYun | 2010 | Science China Earth Sciences2010，53，3： | 23 |
| 6 | Dextral strike-slip of Sanguankou-Niushoushan fault zone and extension of arc tectonic belt in the northeastern margin of the Tibet Plateau显示文摘Sanguankou-Niushoushan 差错(SGK-NSSF ) 的运动学的特征具有到弧的延期的理解的大意义在西藏高原的东北边缘的构造的带。用地调查和各种各样的数据收集方法,包括大规模地质的印射,典型地形学的测量,并且沉积阶层标明日期, SGK-NSSF 展出明显的右罢工滑倒特征并且因此不是一个左首的罢工滑倒差错,由以前的研究人员相信了,这被决定。这研究的结果证明地质的边界为古生代,中生代,和新生代时代都被差错右地打乱,与是类似的指责的排水量。在地志的效果的消除以后,差错的最大的罢工滑倒排水量被发现是 | LEI QiYun ZHANG PeiZhen ZHENG WenJun CHAI ChiZhang WANG WeiTao DU Peng YU JingXing | 2016 | Science China Earth Sciences2016，59，5： | 17 |
| 7 | Near-field surface movement during the Wenchuan M_s8.0 earthquake measured by high-rate GPS显示文摘Based on high-rate (1 Hz) GPS data from the Sichuan GPS Continuous Observation Network on the footwall of the Longmenshan Fault, we have characterized the near-field surface movement process during the 5.12 Wenchuan Earthquake. Results show that the maximum deformation near the fault is larger than the deformation set. Stations on the northern segment of the fault moved towards the epicenter first, and then turned toward the vertical orientation of the fault. Deformation of stations on the southern segment is smaller and recovered. The initial motion at all of the stations was downward followed by periodic up and down movements. Comparing the displacement from high-rate GPS and accelerograph data, we can see that they are consistent prior to the arrival of the principal shock, but afterwards a 10 cm difference is found, even though they are synchronized and in phase. More work is yet to be done to explain this. This is the first time that actual the real near-field surface movements of an earth- quake of M >7.0 have been determined in china. These measurements are therefore of high value for studies of surface rupture processes and the analysis of seismic wave travels paths in this region. | YIN HaiTao ZHANG PeiZhen GAN WeiJun WANG Min LIAO Hua LI XiaoJun LI Jie XIAO GenRu | 2010 | Chinese Science Bulletin2010，55，23： | 11 |
| 8 | Initiation and recession of the fluvial knickpoints:A case study from the Yalu River-Wangtian'e volcanic region,northeastern China显示文摘Initiation and recession of the knickpoints are significant boundary condition for processes of fluvial system.The distribution and recession rates of knickpoints contain information that provides a fundamental understanding of geomorphic processes.In the Yalu River-Wangtian'e volcanic region of northeastern China,broadly distributed flat lava terrain provides an ideal site to study the recession of fluvial knickpoints because knickpoints and waterfalls are well preserved here.Here we describe the distribution of knickpoints in the Yalu River-Wangtian'e volcanic region by combining DEM analysis and numerical modeling.Furthermore,we present a knickpoint celerity model,derived from stream-power incision model,to relate knickpoint recession rate to drainage area.We calibrate important empirical coefficients with our knickpoint celerity model;the best fit erosion coefficient (K) is 1.32×10 8,and the best fit drainage area exponent (m) is 0.69.Error analysis indicates a close correspondence between synthetic and real knickpoints.Finally,we show that knickpoint recession rates in the Yalu River-Wangtian'e volcanic region are ~1-10 mm/a during the early stages of transient incision,and that the present rates are ~1-6 mm/a.Our recession rate results are in good agreement with previous findings from the Aso Volcano and volcanoes near Boso Peninsula (Japan),which have a similar geologic history to the Yalu River-Wangtian'e volcanic region.Our present effort provides new insight into landscape evolution in the Yalu River-Wangtian'e volcanic region in northeastern China. | ZHANG HuiPing ZHANG PeiZhen FAN QiCheng | 2011 | Science China Earth Sciences2011，54，11： | 11 |
| 9 | Development of steel dampers for bridges to allow large displacement through a vertical free mechanism显示文摘Isolation bearings and dampers are often installed between piers and superstructures to reduce the seismic responses of bridges under large earthquakes. This paper presents a novel steel damper for bridges. The damper employs steel plates as energy dissipation components, and adopts a vertical free mechanism to achieve a large deformation capacity. Quasi-static tests using displacement-controlled cyclic loading and numerical analyses using a finite element program called ABAQUS are conducted to investigate the behavior of the damper, and a design methodology is proposed based on the tests and numerical analyses. Major conclusions obtained from this study are as follows:(1) the new dampers have stable hysteresis behavior under large displacements;(2) finite element analyses are able to simulate the behavior of the damper with satisfactory accuracy; and(3) simplified design methodology of the damper is effective. | Pan Peng Yan Hong Wang Tao Xu Peizhen Xie Qiang | 2014 | Earthquake Engineering and Engineering Vibration2014，13，3： | 8 |
| 10 | Drainage Responses to the Activity of the Langshan Range-Front Fault and Tectonic Implications显示文摘Langshan, a monoclinic mountain, which started to uplift since Oligocene, bounds the northwest margin of the Hetao Basin. The continuous activity of the active normal Langshan rangefront fault forms the typical basin-and-range landform in Langshan area and controls the landform evolution of Langshan. Langshan is an ideal place to study relationship between quantitative geomorphological index and active deformation. According to study on knickpoints, fitting on longitudinal channel profiles and steepness index, we demonstrate that the main controlling factors on distribution of normalized steepness index of channels are not climate(precipitation), lithology, sediment flux, but tectonic factor, or the activity of Langshan range-front fault. The short channels in southeast flank, whose lengths are shorter than 16 km, may be still in the non-steady status. If not considering these short channels, the distribution of normalized steepness index along the Langshan range-front fault appears like M-shape pattern, while the normalized steepness index in the middle section is higher than those at both ends. This pattern is well consistent with geometrical segmentation model of the Langshan range-front fault. Combining previous active tectonic research on Langshan range-front fault, which demonstrates the Langshan range-front fault has been in the stage of linkup, we reasonably infer the Langshan range-front fault now is the result of linkup of both fault which continuously bilaterally extended independently. Our tectonic geomorphological study also supports the conclusion that the Langshan range-front fault has been in the stage of linkup. The formation of several knickpoints due to tectonic factor may have been caused by slip-rate variation because of linkup of both independent faults. Based on cognition above, we also proposed the geological and geomorphological evolutionary model of the Langshan range-front fault since Oligocene. | Shaopeng Dong Peizhen Zhang Huiping Zhang Wenjun Zheng Huixian Chen | 2018 | Journal of Earth Science2018，29，1： | 6 |
| 11 | Colluvial wedges associated with pre-historical reverse faulting paleoearthquakes显示文摘Colluvial wedges collapsed from fault scarp can also be used to study reverse faulting paleoearthquakes. Generating processes of reverse faulting colluvial wedges are much more complex than those associated with normal faulting earthquakes. Reverse faulting colluvial wedge is also in triangle shape, and dies away from the fault. Contact between the fault and the colluvial wedge may be a simple straight reverse fault or a combination of an erosive surface in the upper part and a reverse fault in the lower part. Contents and grain sizes increase near the fault and along the base of a colluvial wedge. Based on examples from the piedmont reverse fault and fold along the northern Tainshan, we studied characteristics of reverse faulting colluvial wedges, and discussed the generating processes of reverse faulting colluvial wedges. Reverse faulting generates an unstable scarp hanging in the air immediately after an earthquake. Fallen material deposits along the base of newly formed fault scarp. Erosive | Qidong Deng Peizhen Zhang | 2000 | Chinese Science Bulletin2000，45，17： | 6 |
| 12 | Formation of Bulk Intermetallic Compound AgaSn in Slowly-Cooled Lead-Free Sn-4.0 wt pct Ag Solders显示文摘Sn-Ag alloy system has been regarded as one of the most promising lead-free solder to substitute conventional Sn-Pb eutectic solder. But the formation of bulk Ag3Sn intermetallic compounds (IMCs) during reflow and post heattreatment significantly influences the performance of the solder joints. With an effort to clarify its microstructuralevolution as a function of slow cooling rates, the fraction of bulk IMCs within the slowly solidified Sn-4.0 wt pctAg solder was investigated by standard metallographic and compared with that detected by thermal analysis. It wasfound that the bulk IMCs fraction determined by thermal analysis corresponds quite well with the microstructureobservation results. In accordance with the conventional solidification theory, the lower the applied cooling rate, thefewer the amount of bulk Ag3Sn IMCs formed in Sn-4.0 wt pct Ag alloy. In addition, Vickers hardness measurementresults indicated that the relative coarse eutectic Ag3Sn IMCs distributing in the lamellar eutectic structure favoredthe improvement of the mechanical performance. | Jun SHEN+, Yongchang LIU, Yajing HAN, Peizhen ZHANG and Houxiu GAO College of Materials Science & Engineering, Tianjin University, Tianjin 300072, China | 2005 | Journal of Materials Science & Technology2005，21，6： | 4 |
| 13 | Different earthquake patterns for two neighboring fault segments within the Haiyuan Fault zone显示文摘Characteristic slip and characteristic earthquake models have been proposed for several decades. Such models have been supported recently by high-resolution offset measurements. These models suggest that slip along a fault recurs via similarly sized, large earthquakes. The inter-event strain accumulation rate(ratio of earthquake slip and preceding interseismic time period) is used here to test the characteristic earthquake model by linking the slip and timing of past earthquakes on the Haiyuan Fault. We address how the inter-event strain accumulation rate varies over multiple seismic cycles by combining paleoearthquake studies with high-resolution airborne light detection and ranging(Li DAR) data to document the timing and size of paleoearthquake displacements along the western and middle segments of the Haiyuan Fault. Our observations encompass 5 earthquake cycles. We find significant variations over time and space along the Haiyuan Fault. We observe that on the middle segment of the Haiyuan Fault the rates slow down or increase as an anticorrelated function of the rates of preceding earthquakes. Here, we propose that the inter-event strain accumulation rates on the middle segment of the Haiyuan Fault are oscillating both spatially and temporally. However, along the western segment, the inter-event strain accumulation rate is both spatially and temporally steady, which is in agreement with quasi-periodic and slip-predictable models. Finally,we propose that different fault segments within a single fault zone may behave according to different earthquake models. | ZhiKun Ren ZhuQi Zhang PeiZhen Zhang | 2018 | Earth and Planetary Physics2018，2，1： | 4 |
| 14 | Numerical Simulation on Intergranular Microcracks in Interconnect Lines Due to Surface Diffusion Induced by Stress-,Electro-and Thermo-migration显示文摘Based on the weak formulation for combined surface diffusion and evaporation-condensation,a governing equation of the finite element is derived for simulating the evolution of intergranular microcracks in copper interconnects induced simultaneously by stressmigration,electromigration and thermomigration.Unlike previously published works,the effect of thermomigration is considered.The results show that thermomigration can contribute to the microcrack splitting and accelerate the drifting process along the direction of the electric field.The evolution of the intergranular microcracks depends on the mechanical stress field,the temperature gradient field,the electric field,the initial aspect ratio and the linewidth.And there exists a critical electric fieldχ_c,a critical stress field■,a critical aspect ratioβ_c and a critical linewidth■.When■or■,the intergranular microcrack will split into two or three small intergranular microcracks.Otherwise,the microcrack will evolve into a stable shape as it migrates along the interconnect line.The critical stress field,the critical electric field and the critical aspect ratio decrease with a decrease in the linewidth,and the critical linewidth increases with an increase in the electric field and the aspect ratio.The increase of the stress field,the electric field or the aspect ratio and the decrease of the linewidth are not only beneficial for the intergranular microcrack to split but also accelerate the microcrack splitting process. | ZHOU Linyong HUANG Peizhen | 2019 | Transactions of Nanjing University of Aeronautics and Astronautics2019，36，6： | 3 |
| 15 | Effect of Interconnect Linewidth on Evolution of Intragranular Microcracks Due to Electromigration Analyzed by Finite Element Method显示文摘The effect of interconnect linewidth on the evolution of intragranular microcracks due to surface diffusion induced by electromigration is analyzed by finite element method.The numerical results indicate that there exists critical values of the linewidth hc,the electric fieldχc and the aspect ratioβc.When h>hc,χ<χc orβ<βc,the microcrack will evolve into a stable shape as it migrates along the interconnect line.When h≤hc,χ≥χc orβ≥βc,the microcrack will split into two smaller microcracks.The critical electric field,the critical aspect ratio and the splitting time have a stronger dependence on the linewidth when h≤6.In addition,the decrease of the linewidth,the increase of the electric field or the aspect ratio is beneficial to accelerate microcrack splitting,which may delay the open failure of the interconnect line. | HE Dingni HUANG Peizhen | 2019 | Transactions of Nanjing University of Aeronautics and Astronautics2019，36，2： | 3 |
| 16 | Lushan M_S7.0 earthquake:A special earthquake occurs on curved fault显示文摘Relocation result shows that the aftershocks of the Lushan MS7.0 earthquake spatially distribute in a shape like'half bowl',indicating that the rupture structure of the mainshock is a highly curved surface.Kinematic analysis reveals that a laterally varied dislocation pattern occurs on this curved fault even though a single relative horizontal movement controls slip on this fault.Reverse slip prevails on curved fault.However,significant normal slip is predicted near the edge of north flank.Moreover,the north flank features left-lateral slip while the south flank contrarily features right-lateral slip.The relative scope of aftershock distribution implies inadequate breaking of the curved fault during the mainshock,calling for the attention to potential earthquake risk on the neighboring portions of the coseismic rupture due to significant increase of the coseismic Coulomb stress.Coseismic stress modeling also reveals that it is unnecessary for the stress on ruptured part to be unloaded following the earthquakes on the curved fault.The coseismic stress loading on ruptured elements unveils the specialty of faulting for the Lushan earthquake and we conclude that this specialty is due to the highly curved fault geometry. | ZHANG ZhuQi WANG WeiTao REN ZhiKun ZHANG PeiZhen FANG LiHua WU JianPing | 2013 | Chinese Science Bulletin2013，58，28： | 3 |
| 17 | Far-field coseismic displacements associated with the great Sumatra earthquakes of December 26,2004 and March 29,2005 constrained by Global Positioning System显示文摘Based on continuous GPS observations within China as well as global GPS tracking network, a calculation has been made of far-field coseismic displacements associated with the December, 2004 (Mw = 9.3) and March, 2005 (Mw = 8.7) earthquakes. The far-field coseismic displacements are associated with the 2004 shock range more than 6000―7000 km in both north-south and east-west dimensions, and depict an undulated wave pattern of contraction and extension. The coseismic displacements associ-ated with the 2005 event, however, are distributed near the epicentral region, and the event itself may be an aftershock of the 2004 earthquake. | WANG Min ZHANG Peizhen SHEN Zhengkang LIU Jie SUN Hanrong GAN Weijun LI Peng | 2006 | Chinese Science Bulletin2006，51，14： | 3 |
| 18 | A Preliminary Study on the New Activity Features of the Lajishan Mountain Fault Zone in Qinghai Province显示文摘The Lajishan Mountain fault zone consists of two NE_protruding arcuate faults, i.e. the northern and southern margin fault of Lajishan Mountain with the fault length of 230km and 220km respectively. The fault zone is located in the large_scale compressional structure zone and tectonic gradient zone in_between the NNW_trending right_lateral strike_slip Reshui_Riyueshan fault zone and the NWW_trending left_lateral strike_slip northern margin of west Qinling Ranges fault zone is also an important boundary fault zone, separating the Xining_Minhe basin and the Xunhua_Hualong basin at the southern and northern sides of the Lajishan Mountain respectively. Geologic geomorphic evidences of new activity revealed by field investigations indicate that the latest movement of the Lajishan fault zone was in late Epipleistocene (only a few segments were active in early Holocene) and is mainly of compressive thrusting with slightly left_lateral strike_slip component. The above movement has possibly resulted in the occurrence of about 20 moderate earthquakes of magnitude around 5.0. The Lajishan region can therefore be regarded as a seismotectonic window to reflect tectonic movement and earthquake activity. | Yuan Daoyang Zhang Peizhen Lei Zhongsheng Liu Baichi Liu Xiaolong | 2005 | Earthquake Research in China2005，19，4： | 2 |
| 19 | Insufficient thermalization effects on determining fission-track ages显示文摘Fission-Track Dating (FTD) has been developed as a useful technique for geological studies. Parent elements are measured by counting 235 U tracks induced by thermal neutrons. If insufficient thermalization occurs, fission of 238 U and 232 Th will be induced, and further measurement error will be introduced. Therefore, whether the neutrons are well thermalized or not will affect the FTD results. Due to requirement of safe operation, the 101 reactor was terminated in 2007. By using the 492 reactor as the new thermal neutron reactor, our present paper will attempt to study the feasibility and the potential influence on FTD. By irradiating monitor glass SRM612 and CN5 in pairs, we will study the thermalization situation of the 492 reactor. Irradiated data show that thermal neutrons are not evenly distributed either in horizontal or in vertical dimension. Especially, horizontal heterogeneity is obvious. But we discovered that proper irradiation position in the reactor can meet the requirement of FTD. Under the current irradiation condition, we calculated and assessed the insufficient thermalization effects on determining fission-track ages. We found that the difference between the 232 Th/ 238 U ratios of samples and standards is the main factor to the experiment results. The results will not be affected if the 232 Th/ 238 U value of samples is equal to the standard samples. However, if the 232 Th/ 238 U ratio is larger than that of the standards, the results will be smaller than actual ages. Comparatively, the ages will be more than expected if the 232 Th/ 238 U ratio is less. Therefore, to reduce the irradiation error, we suggest either locating the position of irradiation strictly, or minimizing the influence of lateral heterogeneity by reducing the amount of each sample package. Additionally, accuracy of the experimental results can be improved by increasing standard samples to adjust ζ value and using the monitor of standard glass SRM612 and CN5 together. | PANG JianZhang ZHENG DeWen WAN JingLin LI DaMing ZHANG PeiZhen YANG Jing | 2013 | Science China Earth Sciences2013，56，7： | 2 |
| 20 | Modification to first-order Born approximation for improved prediction of scattered sound from weakly scattering objects显示文摘When deriving the Fourier diffraction theorem based on the first-order Born approximation,the difference between wave number of the scattering object and that of the surrounding medium is ignored,causing substantial errors in sound scattering prediction.This paper modifies the Born approximation by taking into account the amplitude and phase changes between the scattering object and the water due to the wave number difference.By changing the radius and center position of the sampling circle in the Fourier domain,accuracy of the predicted sound scattering is improved.With the modified Born approximation,the computed far-field directional pattern of the scattered sound from a circular cylinder is in good agreement with the rigorous solution.Numerical calculations for several objects with different shapes are used to show applicability and effectiveness of the proposed method. | ZHANG Peizhen WANG Shuozhong WANG Runtian CHEN Yunfei WANG Luxian | 2014 | Chinese Journal of Acoustics2014，33，3： | 2 |
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