乡土书写的另一种可能——读陈启文长篇小说《河床》

《河床》之所以能够从众多乡土小说中脱颖而出,除了创造出"冰裂纹"式的叙事手法外,更主要的原因在于,作者既能站在民间立场,去体验、观察、书写谷花洲的日常生活和芸芸众生,又展示出强大的综合能力,从而既创造出一幅幅血肉丰满、生动可信的民间画卷,又呈现出崭新的融合之美。

一曲人生之河的梦幻乐章——李汉荣《河床》赏读

李汉荣的《河床》，是一曲人生之河的梦幻乐章。 “河也有床，河躺在床上做着川流不息的梦。”文章以富有诗意的妙笔开启了乐章的前奏。起笔的这句拟人化描述，似真似幻，令人称奇，决不同俗于一般意义上的奇情异想。不知不党，我们已随作者走进了一个奇妙的世界：在河床的呵护下，

Seismic reflection characteristics of fluvial sand and shale interbedded layers

A sedimentary geological model is established in order to study the seismic reflection characteristics of channel sand bodies. Synthetic seismic shot gathers are simulated using the acoustic wave equation and then are prestack time migrated. On the imaged data, the reflection characteristics and instantaneous attributes are analyzed and log-constrained impedance inversion is tested. Because of wave field interference, the experimental results show that seismic events do not definitely correspond to the channel sand bodies and that seismic modes of occurrence do not represent the actual ones. The seismic events formed by wave interference may lead to errors and pitfalls in sand body interpretation. The corresponding relations between instantaneous seismic attributes and sedimentary sands are not well established. Log-constrained impedance inversion improves the resolution of channel sands. However, if the inverted resolution is forced to be too high, artifacts related to the initial model may occur.

Equilibrium bed—concentration of nonuniform sediment

Knowledge of the equilibrium bed-concentration is vital to mathematic a l modeling of the river-bed deformation associated with suspended load but prev i ous investigations only dealt with the reference concentration of uniform sedime nt because of difficulties in observation of the bed-concentration. This work i s a first attempt to develop a theoretical formula for the equilibrium bed-conce n tration of any fraction of nonuniform sediment defined at the bed-surface. The f ormula is based on a stochastic-mechanistic model for the exchange of nonunifor m sediment near the bed, and described as a function of incipient motion probabil ity, non-ceasing probability, pick-up probability, and the ratio of the averag e single-step continuous motion time to static time. Comparison of bed-concentra ti on calculated from the proposed formula with the measured data showed satisfacto ry agreement, indicating the present formula can be used for solving the differe ntial equation governing the motion of suspended load.

Numerical simulation of bed degradation in alluvial channels

A numerical model to simulate the bed degradation process in a straight alluvial channel with respect to time and distance is introduced. The simulation takes into account the effect of non uniformity of the bed material, and variations in the dimension of bed forms. The model predicts the changes in the grain size distribution with the time and space during degradation process. The numerical model proposes that the armoring process in degrading channels does not depend only on hydraulic characteristics of the flow but also on variation in the grain size distribution of sediments on the bed. The model was applied and compared with the results obtained from experiments conducted in 24 m recirculating flume for two sizes of sand; a good agreement was found between observed and calculated values.

Effect of Downward Seepage on Turbulent Flow Characteristics and Bed Morphology around Bridge Piers

In this work, experimental investigations have been pursued to analyse the influence of downward seepage on the turbulent characteristics of flow and corresponding changes in vortex structure around circular bridge pier in alluvial channel. Experiments were conducted in sand bed channel with circular piers of different sizes for no seepage, 10% seepage and 20% seepage cases. The measurement of turbulent flow statistics such as velocity and Reynolds stresses is found to be negative within the scour hole at upstream of the pier whereas application of downward seepage retards the reversal of the flow causing a decrement in the velocity and Reynolds stresses. Higher Reynolds shear stress prevails at the downstream side because of the production of wake vortices. Contribution of all bursting events to the total Reynolds shear stress production has been observed to increase with downward seepage. The analysis of integral scale suggest that size of eddies increases with seepage, which is responsible for increase in particle mobility. Initially rate of scouring is more which abatements gradually with expanding time as well as with the increased of downward seepage. Presence of downward seepage reduces the depth and length of vortex and shifts towards downstream side of the pier.

Environmental Characterization of Periphyton Community

The present paper deals with the behavior of the Attached Microbial Community (AMC) for water self-purification at different riverbeds in a typical local river. The study quantitatively investigated the problem starting with in-situ sampling. It was found that more biomass of AMC was at riffles with wider distribution than in pools. High current velocity (HCV) plays a negative role at the initial stage of attachment on the riverbed, but HCV aids the community proliferation after stable attachment. External disturbances such as rainfalls and discharges from dams or reservoirs would detach the periphyton depending on the intensity of turbulence in water. However, it was discovered that the flock of periphyton could be restored very quickly because it was not completely removed. Thus, in order to enhance self-purification by periphyton, a suitable configuration of the riverbed must be constructed, and occasional appropriate repair along the channels would improve the decontamination of the river.

Formation and development of stream potholes in a gorge in Guangdong

The goal of this study is to provide information on the process of pothole growth on a gorge streambed.Pothole geometries were measured in a reach of the Dabu river bed at the head of a gorge more than 200 m deeply incising into a 650-750 m high planation surface formed in the middle Miocene in northern Guangdong,China.Geometric and derivative data of the potholes obtained from fieldwork were interpreted using standard statistical methodologies.Our study shows that the formation and development of a stream pothole were only related to local conditions of a stream reach where the pothole occurs;the weaknesses,which are usually intersect fractures,typically interconnected vertical joints,or triangular pits generated by hitting of rock fragments during floods,initiate the pothole development on a streambed;the geometrical dimensions of the potholes are controlled by tectonic joints developed in bedrock of the stream reach;the radius and the depth of potholes are strongly(log) positive correlated;the pothole shapes and the flow patterns are inconstant during pothole growth;a pothole can be formed within a short period,but cannot be fully developed and maintained for a long time in a strong incision streambed.The finding in our study can improve the understanding of Quaternary environment in Guangdong.

Experiments on Channel Evolution Caused by Check-dam Failure

A 10 m long,0.2 m wide flume was employed to simulate the channel bed evolution of check-dam failure.The experiment longitudinal profiles,the gradient of channel bed,head-cutting propagation distance and deposition length were compared with the theoretical solution derived from a sediment transport diffusion equation.In contrast with the theoretical solution,two different gradients were obtained upstream and downstream of the check-dam.The theoretical solution provides a good description of the changes upstream of the check-dam. The ratio of clear water depth to sediment moving layer thickness in the experiment was analyzed and showed that high concentration sediment laden flow was taken in the incipient of check-dam failure,which may be the reason why the experiment result was slightly different from the theoretical solution in the downstream of check-dam.

DYNAMIC ANALYSIS OF PIPELINES LAID THROUGH ALLUVIAL VALLEY

This paper describes the dynamic characteristics of pipelines laid through alluvial valleys. We assume that the alluvial valley has a semi-cylindrical cross-section. The ground motion of alluvial valley under harmonic seismic SH waves is carried out, and the pipeline-soil dynamic interaction is taken into account. Though simple, the model may qualitatively explain the earthquake damages of pipelines laid through an alluvial river valley.

Experimental Study on the Dam-Break Hydrographs at the Gate Location

When studying the dam-break flow phenomenon,the basic hydrodynamic features of the dam-break flow at the gate location should be verified primarily.In this study,laboratory experiments were performed in a rectangular and horizontal flume with the same initial water head setting on the dry and wet downstream bed conditions.Water surface elevation was extracted through image analysis and validated by comparing with the data measured using a wave gauge.Temporal variation of the water surface elevation at the gate location,quantified in terms of high-speed video recorded images,can be divided into three stages,the sharp decreasing stage,the relatively steady stage,and the gradually decreasing stage.Applicability of several classic analytical solutions of the dam-break problem at the gate location was validated using present experimental data.Ritter's solution is effective for the dry bed condition while Stoker's solution could be applied to the wet bed case,and both are only applicable during the steady stage.Lin' solution reproduces the gate-site hydrographs well during both the relatively steady and the gradually decreasing stages,especially for the condition under which the down-upstream water depth ratio is smaller than 0.138.

A Note on the Solution of Water Wave Scattering Problem Involving Small Deformation on a Porous Channel-Bed

The solution of water wave scattering problem involving small deformation on a porous bed in a channel, where the upper surface is bounded above by an infinitely extent rigid horizontal surface, is studied here within the framework of linearized water wave theory. In such a situation, there exists only one mode of waves propagating on the porous surface. A simplified perturbation analysis, involving a small parameter ε （≤1） , which measures the smallness of the deformation, is employed to reduce the governing Boundary Value Problem （BVP） to a simpler BVP for the first-order correction of the potential function. The first-order potential function and, hence, the first-order reflection and transmission coefficients are obtained by the method based on Fourier transform technique as well as Green＇s integral theorem with the introduction of appropriate Green＇s function. Two special examples of bottom deformation： the exponentially damped deformation and the sinusoidal ripple bed, are considered to validate the results. For the particular example of a patch of sinusoidal ripples, the resonant interaction between the bed and the upper surface of the fluid is attained in the neighborhood of a singularity, when the ripples wavenumbers of the bottom deformation become approximately twice the components of the incident field wavenumber along the positive x -direction. Also, the main advantage of the present study is that the results for the values of reflection and transmission coefficients are found to satisfy the energy-balance relation almost accurately.

Comparison of River Terraces in the Middle Reach Valleys of the Yellow River and Analysis on the Multi-Gradational Features of Tectonism in the Formation of Terrace Series

Where the Yellow River flows through the Haiyuan-Tongxin arc-form tectonic region on the northeastern side of the Qinghai-Xizang (Tibet) Plateau, as many as 10～21 basis and erosion terraces have been produced, among which the biggest altitude above river level is 401m and the formation age of the highest terrace is 1.57 Ma B.P. Based on comparative analysis of the Yellow River terraces located separately in the Mijiashan mountain, the Chemuxia gorge, the Heishanxia gorge and the other river terraces in the vast extent of the northern part of China, it has been found that the tectonic processes resulting in the formation of the terrace series is one of multi-gradational features, i.e., a terrace series can include the various terraces produced by tectonic uplifts of different scopes or scales and different ranks. The Yellow River terrace series in the study region can be divided into three grades. Among them, in the first grade there are 6 terraces which were formed separately at the same time in the vast extent of the northern part of China and represent the number and magnitude of uplift of the Qinghai-Xizang Plateau since 1.6 Ma B. P.; in the second grade there are 5 terraces which were separately and simultaneously developed within the Haiyuan-Tianjingshan tectonic region and represent the number and magnitude of uplift of this tectonic region itself since 1.6Ma B.P.; in the third grade there are 10 terraces which developed on the eastern slope of the Mijiashan mountain and represent the number and amplitude of uplift of the Haiyuan tectonic belt itself since 1.6Ma B.P. Comparison of the terrace ages with loess-paleosoil sequence has also showed that the first grade terraces reflecting the vast scope uplifts of the Qinghai-Xizang Plateau are very comparable with climatic changes and their formation ages all correspond to the interglacial epochs during which paleosoils were formed. This implies that the vast extent tectonic uplifts resulting in river down-cutting are closely related to the warm-humid climatic periods which can also result in river downward erosion after strong dry and cold climatic periods, and they have jointly formed the tectonic-climatic cycles. There exists no unanimous and specific relationship between the formation ages of the second and third grade terraces and climatic changes and it is shown that the formation of those terraces was most mainly controlled by tectonic uplifts of the Tianjingshan block and the Haiyuan belt. The river terraces in the study region, therefore, may belong to 2 kinds of formation cause. One is a tectonic-climatic cyclical terrace produced jointly by vast extent tectonic uplifts and climatic changes, and the terraces of this kind are extensively distributed and can be well compared with each other among regions. Another is a pulse-tectonic cyclical terrace produced by local tectonic uplifts as dominant elements, and their distribution is restricted within an active belt and can not be compared with among regions.

Geometry and Dynamic Forces along an Inclined Hydraulic Jump over a Rough Channel Bed

In this investigation, based on previous measurements, the geometry and dynamic forces along an inclined （angle φ, with 0^0 〈 qφ φ 8^0 ） hydraulic jump over a variation of rough and smooth channel beds, are examined and compared among them. The roughness is produced through transverse strips （of square cross section） covering the entire channel width and at various normal distributions along the channel. Froude numbers are varying up to 18.5 and conjugate depths＇ ratios up to 18.4. The water free surface profiles, the conjugate depths＇ ratios, the jumps＇ dimensionless lengths are examined and a prediction of exercised forces, in dimensionless terms, is also presented. The results and especially the latter force prediction may help the hydraulic and structural engineers when dealing with such hydraulic jumps.

Numerical Modeling of Local Scour Around Hydraulic Structure in Sandy Beds by Dynamic Mesh Method

Local scour, a non-negligible factor in hydraulic engineering, endangers the safety of hydraulic structures. In this work, a numerical model for simulating local scour was constructed, based on the open source code computational fluid dynamics model Open FOAM. We consider both the bedload and suspended load sediment transport in the scour model and adopt the dynamic mesh method to simulate the evolution of the bed elevation. We use the finite area method to project data between the three-dimensional flow model and the two-dimensional(2D) scour model. We also improved the 2D sand slide method and added it to the scour model to correct the bed bathymetry when the bed slope angle exceeds the angle of repose. Moreover, to validate our scour model, we conducted and compared the results of three experiments with those of the developed model. The validation results show that our developed model can reliably simulate local scour.

Early Cretaceous precious fossil-bearing beds in Weijialing—Yaolugou of Jianchang Basin,western Liaoning

The Jianchang Basin is one of the main localities of the precious fossils of Jehol Biota in western Liaoning.The fossil-bearing horizons are mainly in the Yixian-and Jiufotang formations.In the Weijialing--Yaolugou of southwest Jianchang Basin,many precious fossils have been found at Luojiagou Bed of the 2nd Member of the Yixian Formation and at Xidian Bed of the 1st member of the Jiufotang Formation.The geologic setting,sedimentary environment and paleogeography of the precious fossil-bearing beds were also studied.

TWENTY-THREE CASES OF ATROPHIC RHINITIS TREATED BY DEEP PUNCTURE AT THREE POINTS IN THE NASAL REGION

Atrophic rhinitis is a disease which manifests itself mainly by anosmia due to dryness and atrophy of the nasal mucosa. There is no specific therapy for the disease at present. In the past few years, 23 cases of atrophic rhinitis were treated mainly by deep puncture at three points in the nasal region with satisfactory results. In order to find out the functional changes of the nasal mucosa, the mucociliary transport rate (MTR), surface temperature of the conchal mucosa, acid-base scale of nasal secretion, and volume of nasal secretion were determined before and after the treatment.

Research on infiltration clogging effect and its application prospect in anti-seepage project

Clogging effect,as a new concept in geological engineering,is a phenomenon of permeability decreasing under seeping in reservoir dam foundation of the alluvial and diluvial deposits with deep and thick layer,coarse particle and high permeability in mountains-gully rivers of Tibetan Plateau.A clogging infiltration instrument has been designed successfully and a series of simulation tests have been done.Based on large amounts of data,it is confirmed that the existence of the clogging effect and the law of infiltration clogging is found out.Three indexes are proposed such as "optimal size of particle","optimal size range of particle" and "characteristic pore",which are closely related with effect of infiltration clogging.The concept and results can offer a new idea to solve problems on anti-seepage of dam foundation in mountains-gully rivers environment and to study artificial clogging,meanwhile supplement of the concept of seepage deformation.

河床

河也有床，河躺在床上做着川流不息的梦。河躺着，从远古一直到此刻，河不停地转弯改道，那是它在变换睡眠的姿势。

资讯

奥拉弗·埃利亚松个展“河床”2014年8月20日至2015年1月4日，丹麦冰岛裔艺术家奥拉弗·埃利亚松的个展“河床”在丹麦首都哥本哈根的路易斯安娜现代艺术馆举行。埃利亚松是当代最有影响力的艺术家之一，他以气象、环境与自然现象为创作主题，通过精湛的科技手段，让观众产生强烈共鸣。此次展览的核心作品《河床》利用了路易斯安娜现代美术馆与自然、建筑、艺术之间的特有联系，以铺满地面的石砾、泥土构成河床，使艺术馆成为一件风景式的装置艺术品，并与馆外的真实世界相连。