一种改进的滑走切片染色技术在竹秆解剖上的应用

传统的滑走切片制片过程中易发生切片卷曲,只能单个染色且染色不均匀。采用透明胶带及双面胶协助转移切片固定到载玻片上,制作后的多组切片可放入染色筐进行批量染色。该方法制作的切片不易脱落,而且提高了染色效率,简单易行,适用于本科实验教学的推广,对材质较硬的植物组织切片的研究也有极大的推动作用。利用该方法对云南箭竹竹秆制片,并对其木质素染色方法进行比较,结果表明盐酸-间苯三酚法的染色效果特异性最强,更适合竹秆的木质素染色。

采煤机组电缆线自动滑走装置在综采面的应用

介绍了采煤机组电缆线自动滑走装置的结构组成、工作原理。该装置能带动电缆自动收放,减小了电缆拖移的阻力,方便、省时、省力,提高了工作效率,减轻了劳动强度,实现了电缆合理有序布置,减少了电缆拉移工作量。采煤机组电缆线自动滑走装置满足了安全生产和技术要求,与老式单轨吊相比,获得了一定的经济效益。

滑走两用鞋的开发与实用性探讨

大家都知道,溜旱冰是一种广大民众喜爱的娱乐健身运动,它使人们由缓慢步行变为快速滑行,大大提高行进速度,省时省力。但轮滑运动只能在特定的平整场地进行,而不能作为代步工具上路使用,当遇到台阶或凹凸不平的地段时,即受到阻碍,不能行进。

上海二月房屋开价出现大面积下滑走势

专项调查显示,除浦东和南市两区之外,与一月份相比,二月份大部分区域公布的销售价格呈全线下降之势,尤以徐汇、长宁、闵行、卢湾及普陀等区最为突出。 西南各区的楼盘占据了上海楼市的半壁江山,而此次房价变化更波及环线内外。卢湾当属上海市中心黄金区域。

Semi-analytical solution for mechanical analysis of tunnels crossing strike-slip fault zone considering nonuniform fault displacement and uncertain fault plane position

The tunnel subjected to strike-slip fault dislocation exhibits severe and catastrophic damage.The existing analysis models frequently assume uniform fault displacement and fixed fault plane position.In contrast,post-earthquake observations indicate that the displacement near the fault zone is typically nonuniform,and the fault plane position is uncertain.In this study,we first established a series of improved governing equations to analyze the mechanical response of tunnels under strike-slip fault dislocation.The proposed methodology incorporated key factors such as nonuniform fault displacement and uncertain fault plane position into the governing equations,thereby significantly enhancing the applicability range and accuracy of the model.In contrast to previous analytical models,the maximum computational error has decreased from 57.1%to 1.1%.Subsequently,we conducted a rigorous validation of the proposed methodology by undertaking a comparative analysis with a 3D finite element numerical model,and the results from both approaches exhibited a high degree of qualitative and quantitative agreement with a maximum error of 9.9%.Finally,the proposed methodology was utilized to perform a parametric analysis to explore the effects of various parameters,such as fault displacement,fault zone width,fault zone strength,the ratio of maximum fault displacement of the hanging wall to the footwall,and fault plane position,on the response of tunnels subjected to strike-slip fault dislocation.The findings indicate a progressive increase in the peak internal forces of the tunnel with the rise in fault displacement and fault zone strength.Conversely,an augmentation in fault zone width is found to contribute to a decrease in the peak internal forces.For example,for a fault zone width of 10 m,the peak values of bending moment,shear force,and axial force are approximately 46.9%,102.4%,and 28.7% higher,respectively,compared to those observed for a fault zone width of 50 m.Furthermore,the position of the peak internal forces is influenced by variations in the ratio of maximum fault displacement of the hanging wall to footwall and the fault plane location,while the peak values of shear force and axial force always align with the fault plane.The maximum peak internal forces are observed when the footwall exclusively bears the entirety of the fault displacement,corresponding to a ratio of 0:1.The peak values of bending moment,shear force,and axial force for the ratio of 0:1 amount to approximately 123.8%,148.6%,and 111.1% of those for the ratio of 0.5:0.5,respectively.

The application of seismic-geological integrated interpretation in the eastern depression of the Liaohe oil field

It is very important to comprehensively interpret areal seismic data with geological data in a research area. For the structural interpretations in the middle depression of the eastern basin of Liaohe oilfield, we first analyze and study geological phenomena on outcrop pictures collected in the field and establish geological outcrop models. Second, we make fault and structural interpretations based on the structural characteristics of the outcrop pictures. Third, we analyze the migration, accumulation, and formation of oil and gas using characteristics of seismic profiles. By geologic and geophysical comprehensive interpretation, it is inferred that, in the research area, the dominant factor controlling oil and gas accumulation is strike-slip faults. Structural modes and the relationship of the oil and gas in the Huangshatuo and Oulituozi oil fields are also analyzed and investigated.

Origin of the regional stress field along the Liquine-Ofqui Fault Zone(LOFZ),Southern Chilean Andes by means of FE Simulation

The Liquine-Ofqui Fault Zone(LOFZ) of southern Chilean Andes is one of the largest active strike-slip fault zones.There is an ongoing debate regarding the origin of the stress field along the LOFZ due to its complex geometry.This paper represents a study of the origins of the LOFZ regional stress field.Stress fields are calculated by finite element(FE) analysis.The two possible stress origins, i.e., oblique plate convergence and ridge collision/indenter tectonics of Chile ridge against Peru-Chile trench, have been emphasized in the present study.Three types of boundary conditions for the three particular models have been applied to calculate stress fields.Models are assumed to be elastic and plane stress condition.Modeling results are presented in terms of four parameters, i.e., orientation of maximum horizontal stress(σ H max ), displacement vector, s train distribution, and maximum shear stress(τmax ) contour line within the model.The results of the first model with oblique plate convergence show inconsistency between the geometric shape of the LOFZ and the distribution of the four parameters.Although more realistic results are obtained from the second model with normal ridge collision, there are few coincident in the LOFZ geometry and regional stress field.The third model with normal and oblique ridge collision is reasonable in understanding the origin of stress field and geometrical condition in the lithosphere of the LOFZ.

Episodic Orogeny Deduced from Coeval Sedimentary Sequences in the Foreland Basin and Its Implication for Uplift Process of Longmen Mountain,China

Longmen Mountain located at the boundary between the Sichuan Basin and Tibetan Plateau,representing the steepest gradient of any edges of the plateau.Three endmember models of uplift process and mechanism have been proposed,including crustal thickening,crustal flow,and crustal isostatic rebound.Here we use coeval sedimentary sequences in the foreland basin to restraint uplift process and mechanism in the Longmen Mountain.The more than 10,000 m thick Late TriassicQuaternary strata filled in this foreland basin and can be divided into six megasequences that are distinguished as two distinct types.The first type is the wedge-shaped megasequences which are sedimentary response of strong active thrust loading events,characterized by a high rate of subsidence and sediment accumulation,coarsening-upward succession and a dual-sourced sediment supply.This type includes Late Triassic,Late Jurassic to Early Cretaceous and Late Cretaceous to Paleogene megasequences.The second type is the tabular megasequences,characterized by the low rate of subsidence and sediment accumulation,finingupward succession,and a single-sourced sediment supply,which is sedimentary response of isostatic rebound and erosion unloading.This type includes the Early to Middle Jurassic,Middle Cretaceous and Neogene to Quaternary megasequences.Basing on sedimentary,active tectonic,geomorphic evidence,we infer that the direction has been reversed from SSWdirected sinistral strike-slip to NNE-directed dextral strike-slip during 40-3.6 Ma,and since 3.6 Ma,the Longmen Mountain thrust belt belong to times of isostatic rebound and erosional unloading with NNEdirected dextral strike-slip.This suggests that crustal isostatic rebound is a primary driver for uplift and topography of the present Longmen Mountain.The Wenchuan(Ms8.0) earthquake,which ruptured a large thrust fault with NNE-directed dextral strikeslip along the range front,is an active manifestation of this crustal isostatic rebound process with dextral strike-slipping and shortening.This process may be the cause for the Wenchuan Earthquake and the apparent paradox of high relief,little shortening,the relative dearth of historical seismicity in the region.

Strain analysis of buried steel pipelines across strike-slip faults

Existing analytical methods of buried steel pipelines subjected to active strike-slip faults depended on a number of simplifications.To study the failure mechanism more accurately,a refined strain analytical methodology was proposed,taking the nonlinear characteristics of soil-pipeline interaction and pipe steel into account.Based on the elastic-beam and beam-on-elastic-foundation theories,the position of pipe potential destruction and the strain and deformation distributions along the pipeline were derived.Compared with existing analytical methods and three-dimensional nonlinear finite element analysis,the maximum axial total strains of pipe from the analytical methodology presented are in good agreement with the finite element results at small and intermediate fault movements and become gradually more conservative at large fault displacements.The position of pipe potential failure and the deformation distribution along the pipeline are fairly consistent with the finite element results.

Scaling of Reduced Energy or Apparent Stress and Its Seismological Significance

Comparison between the NEIC broadband radiated energy catalogue and the Harvard CMT catalogue provides information about apparent stress. In spite of its significant uncertainties and limited reliability, the clues obtained from this comparison seem interesting in the physics of earthquakes. Scaling of apparent stress provides information about the dynamic friction along an earthquake fault. Relation between reduced energy and seismic moment implies that for strike-slip earthquakes, velocity-dependent friction plays a predominant role, while for non-strike-slip earthquakes, slip-dependent friction is predominant. It is also found that strike-slip events with extremely low apparent stress tend to occur “in single”, which is applied to the prediction of the seismic tendency following the 2001 Qinghai-Xizang (Tibet) border M W7.8 earthquake.

Slip-Rate on the Middle Altyn Tagh Fault since the Holocene Period

By analyzing high-resolution SPOT images and in combination with fieldwork and chronometry, three typical fault-offset sites on the south-middle Altyn Tagh strike-slip fault were studied to obtain the sinistral horizontal slip rate of the fault. At Annanba, the left-lateral strike-slip rate on a branch of the south Altyn Tagh fault is 7.5±1.7 mm/a since 9.36±0.73ka BP. At Seven Spring, the fault has four branches and the left-lateral strike-slip rate on one of them is 2.3±0.5mm/a since 13.86±1.07ka BP, and it is deduced that the total slip-rate of all the four branches is 6.9±1.5～ 9.2±2.0 mm/a since Holocene. At Yuemakeqi, the left-lateral strike-slip rate of the fault is 10.6±3.0mm/a since 4.73±0.38 ka BP. A slip-rate of 7～11mm/a on the middle segment of the Altyn Tagh fault (between 88°30’E and 93°05’E) since Holocene can be deduced from the three sites mentioned above and the result is similar to the latest GPS observation.

Study of Paleoearthquakes by Excavation of Grouped Trenches on the Zemuhe Fault in Daqingliangzi,Xichang,Sichuan

Uncertainties are common in the dating of paleoearthquakes.To improve the credibility of the dating of paleoearthquakes,analysis was done on fault activity,sedimentary environment and seismo-geomorphology to investigate paleoearthquakes along the Zemuhe active fault zone.Grouped trenches were excavated near Daqingliangzi,which revealed three palaeoearthquake events aged 160a,3100a and 5500a～8900a,respectively,including recurrence intervals of about 3000a.Sedimentary processes related to strike-slip fault type earthquakes were discussed,and a sedimentary model was put forward for strike-slip faults at hillsides where drumlin and reverse scarp developed.

The Emergency Scientific Investigation on the Surface Rupture Zone of the M_S 7.1 Yushu Earthquake

The coseismic surface rupture zone of the seismogenic fault of the Ms7.1 Yushu earthquake includes three left-stepping main ruptures, striking 300°- 320°, in general. An approximately 2km-long en echelon tension fissure zone was found at Longbao town. The main rupture in the northern part is about 16km long, about 9kin long in the middle part, and about 7km long in the southern part, with a total length of 34km. Each of the main ruptures consists of a series of en echelon sub-ruptures represented by a series of compression bulges alternating with tension fissures or by en echelon fissures. The rupture at Changusi, the southernmost of the ruptures, is characterized by vertical displacement, with a value of 50cm. The rupture zone shows left-lateral strike-slip characteristics. The maximal horizontal slip is on the northern main rupture, with a value of 1.8m.

Tectonic Background of the Yutian M_S7.3 Earthquake in 2014 and Its Relationship with the Yutian M_S7.3 Earthquake in 2008

The regional tectonic background and characteristics of active faults of the Yutian MS7.3earthquake on February 12,2014 are discussed in this paper.After the analysis of the epicenter area of the MS7.3 earthquake in 2014 and the focal mechanisms of the former strong earthquakes around it,the authors deduced that the seismogenic fault of the MS7.3earthquake is the east branch of the Ashikule fault.The MS7.3 earthquake in 2014 and the MS7.3 earthquake in 2008 are two strong earthquake events on the different sections of the Altun Tagh fault,where the fault behavior changes from sinistral slip to normal faulting because of the extensional tail effects in the southern end of the Altun Tagh fault.It is concluded that the two MS7.3 earthquakes have the same dynamic source,and the MS7.3earthquake in 2008 promoted the occurrence of the MS7.3 earthquake in 2014.Finally,we calculate the Coulomb stress change to the seismogenic fault of the MS7.3 earthquake in2014 from the MS7.3 earthquake in 2008 using the layered crust model.The result also shows that the MS7.3 earthquake in 2008 accelerated the occurrence of the MS7.3earthquake in 2014.

Geological Structure and Quaternary Activity of the Zhangjiakou Fault, Northern China

Based on detailed field investigations, this paper describes the geometrical characteristics and tectonic activities of the Zhangjiakou fault at the northwest of Beijing. This fault strikes mainly northwest to west, short parts of which strike near east to west, dipping north, and extends over a length of 70km. It is a major geological and geomorphologicai margin, controlling the neotectonic movement in this region. On the south side of the Zhangjiakou fault are the Late Quaternary unconsolidated deposits, forming basins; while on the other side are Mesozoic volcano debris and Pre-Mesozoic metamorphic rocks, forming lower mountains and hills. The Zhangjiakou fault consists mainly of high-angle inverse strike-slip fault and partially of normal strike-slip fault. Among these, the north-dipping NW-NWW-trending secondary faults, constituting the main fracture of the fault, have inverse characteristics; those near the EW-trending secondary faults are links of the former faults, with a smaller length and normal faulting characteristics. Thus, the Zhangjiakou fault is a north-dipping inverse and partially south-dipping normal strike-slip fault. The Zhangjiakou fault has been continuously active since the Quaternary. With the exception of the western end extension, which has been active since the late Pleistocene, the main part of the fault has been active since the Holocene. The central main segment of the Zhangjiakou fault is more active. Since the mid-late period of the late Pleistocene, the average vertical slip rate of a single fault has been over 0. 07mm/a - 0. 30mm/a. The Zhangjiakou fault has multi-slip surfaces, and the total vertical slip rate reaches 1.33mm/a, estimated from the Qingshuihe river terraces and the relevant drilling data.

A Study on the Characteristics of the Yutian,Xinjiang M_S7.3 Earthquake,February 12,2014

The February 12, 2014, Ms7. 3, earthquake in Yutian, Xinjiang, China, occurred as a result of shallow strike-slip faulting in the tectonicaUy complex region of the northern Tibetan Plateau, with a depth of 17kin. This earthquake occurred several hundred kilometers north of the convergent India-Eurasia plate boundary. The epicenter location of the Yutian earthquake, 36. 1° N, 82. 5° E, is ll0km north of Yutian County, Hotan Prefecture. A large number of aftershocks from ML2. 0 to ML3. 0 occurred until 12：00 o＇clock, February 23, 2014 and the largest aftershock, Ms5. 7, occurred at 17：24 μm. , February 12, 2014. The b and h value of Yutian sequence are 0.70 and 1.29, respectively. The waiting time method reveals that the strong aftershocks above ML 4. 5 comply with a linear relationship, which is consistent with the characteristics of a mainshock-aftershock sequence. Furthermore, we calculate the source parameters and analyze the rupture process based on the empirical relationships for the Yutian earthquake, and the results indicate a frictional undershoot behavior in the dynamic source process of the Yutian earthquake, which is also in agreement with the lower and similar b values compared with the 2008 Ms 7.3 Yutian earthquake and the 2012 Ms 6. 2 Yutian earthquake.

Slip Rates of the Major Faults on the Mid-southern Section of the North-South Seismic Belt Calculated from the Block Theory

In this paper, using the 1999 ~ 2007 GPS velocity field data, and by choosing the optimal block model, we obtained the deformation models applicable to the boundary zones of major blocks and the slip rates of block boundary faults on the mid-southern segment of the North-South Seismic Belt. The results show that： on the Longmenshan fault zone, the tensional and compressive slip rate is small on the Baoxing-Wenchuan segment, about 0. 5 ~ 1.8mm·a^-1, and the rate is relatively significant on the segment of the Wenchuan--Maoxian, as 1.8 ~3.8mm·a^-1; on the Xianshuihe fault belt, there is a certain difference in spatial distribution between the tensional slip rag.e and strike-slip rate： the tensional slip rate （ 8. lmm^a-1） is bigger than the sinistral strike-slip rate （ 4.8mm·a^-1） at the north of the Luhuo region; the tension and compression slip rate is basically the same as the strike-slip rate at Luhuo-Dawu; the Dawu-Kangding section presents a trend of decreased strike-slip rate and increased tensional slip rate; the Kangding-ghimian segment shows a strike-slip nature; the strike-slip rate is significantly greater than the tension/compression rate on the Xiaojiang fault zone; the slip rate on the Red River fault zone shows obvious spatial segmentation, the slip rate is smaller in its northwest part, but with a certain amount of tensional/compression component, 4. 7mm·a^-1 on the Jingdong segment. The segment east of Jingdong （ western Gejiu） is mainly of strike-slip, with a slip rate of 4. 5mm·a^-1.