Predicting Surface Roughness and Moisture of Bare Soils Using Multiband Spectral Reflectance Under Field Conditions

Soil surface roughness, denoted by the root mean square height(RMSH), and soil moisture(SM) are critical factors that affect the accuracy of quantitative remote sensing research due to their combined influence on spectral reflectance(SR). In regards to this issue, three SM levels and four RMSH levels were artificially designed in this study; a total of 12 plots was used, each plot had a size of 3 m × 3 m. Eight spectral observations were conducted from 14 to 30 October 2017 to investigate the correlation between RMSH, SM, and SR. On this basis, 6 commonly used bands of optical satellite sensors were selected in this study, which are red(675 nm), green(555 nm), blue(485 nm), near infrared(845 nm), shortwave infrared 1(1600 nm), and shortwave infrared 2(2200 nm). A negative correlation was found between SR and RMSH, and between SR and SM. The bands with higher coefficient of determination R~2 values were selected for stepwise multiple nonlinear regression analysis. Four characterized bands(i.e., blue, green, near infrared, and shortwave infrared 2) were chosen as the independent variables to estimate SM with R~2 and root mean square error(RMSE) values equal to 0.62 and 2.6%, respectively. Similarly, the four bands(green, red, near infrared, and shortwave infrared 1) were used to estimate RMSH with R~2 and RMSE values equal to 0.48 and 0.69 cm, respectively. These results indicate that the method used is not only suitable for estimating SM but can also be extended to the prediction of RMSH. Finally, the evaluation approach presented in this paper highly restores the real situation of the natural farmland surface on the one hand, and obtains high precision values of SM and RMSH on the other. The method can be further applied to the prediction of farmland SM and RMSH based on satellite and unmanned aerial vehicle(UAV) optical imagery.     

Seismotectonics of the Taiwan Shoal region in the northeastern South China Sea: Insights from the crustal structure

A cluster of earthquakes occurred in the Taiwan Shoal region on the outer rise of the Manila Trench. Although most were of small to medium magnitudes, one strong earthquake occurred on September 16, 1994. Several previous studies have provided important information to progress our understanding of this single earthquake. However, little is currently known about the earthquake cluster, and it is necessary to investigate the deep crustal structure of the Taiwan Shoal region to understand the mechanisms involved in controlling and generating it. This study presents a two-dimensional seismic tomographic image of the crustal structure along the OBS2012 profile based on ocean-bottom seismograph (OBS) data, which exhibits a high-velocity anomaly flanked by low-velocity anomalies in the upper crust beneath the Taiwan Shoal. In this study, 765 earthquakes (Richter magnitude M_L > 1.5) occurring between 1991 and 2015 were studied and analyses of earthquake epicenters, regional faults, and the crustal structure provides an improved understanding of the nature of active tectonics in this region. Results of analyses indicate firstly that the high-velocity area represents major asperities that correspond to the location of the earthquake cluster and where stress is concentrated. It is also depicted that the earthquake cluster was influenced by fault interactions. However, the September 1994 earthquake occurred independently of these seismic activities and was associated with reactivation of a preexisting fault. It is also determined that slab pull is resisted by the exposed precollision accretionary prism, and the resistive force is causing accumulation of inplane compressive-stress. This may trigger a future damaging earthquake in the Taiwan Shoal region.     

大肠杆菌内毒素引起肉鸡腹水症的诊治

头面部肿胀、下痢、腹水、腹腔纤维素性渗出及肝脏周围炎、腹膜炎是大肠杆菌内毒素引起的肉鸡腹水症的主要特征,通过临诊症状、病理剖检及细菌分离确诊本病,采用环境消毒及抗生素治疗可有效控制本病.     

Two-dimensional numerical simulation of flow around three-stranded rope

Three-stranded rope is widely used in fishing gear and mooring system. Results of numerical simulation are presented for flow around a three-stranded rope in uniform flow. The simulation was carried out to study the hydrodynamic characteristics of pressure and velocity fields of steady incompressible laminar and turbulent wakes behind a three-stranded rope. A three-cylinder configuration and single circular cylinder configuration are used to model the three-stranded rope in the two-dimensional simulation. The governing equations, Navier-Stokes equations, are solved by using two-dimensional finite volume method. The turbulence flow is simulated using Standard κ-ε model and Shear-Stress Transport κ-ω(SST) model. The drag of the three-cylinder model and single cylinder model is calculated for different Reynolds numbers by using control volume analysis method. The pressure coefficient is also calculated for the turbulent model and laminar model based on the control surface method. From the comparison of the drag coefficient and the pressure of the single cylinder and three-cylinder models, it is found that the drag coefficients of the three-cylinder model are generally 1.3–1.5 times those of the single circular cylinder for different Reynolds numbers. Comparing the numerical results with water tank test data, the results of the three-cylinder model are closer to the experiment results than the single cylinder model results.     

Scaling relation between Sunyaev–Zel’dovich effect and X-ray luminosity and scale-free evolution of cosmic baryon field

It has been revealed recently that, in the scale free range, i.e. from the scale of the onset of nonlinear evolution to the scale of dissipation, the velocity and mass density fields of cosmic baryon fluid are extremely well described by the self-similar log-Poisson hierarchy. As a consequence of this evolution, the relations among various physical quantities of cosmic baryon fluid should be scale invariant, if the physical quantities are measured in cells on scales larger than the dissipation scale, regardless the baryon fluid is in virialized dark halo, or in pre-virialized state. We examine this property with the relation between the Compton parameter of the thermal Sunyaev–Zel’dovich effect, y(r), and X-ray luminosity, L_x(r), where r being the scale of regions in which y and L_x are measured. According to the self-similar hierarchical scenario of nonlinear evolution, one should expect that (1) in the y(r) ? L_x(r) relation, y(r) = 10^A(r)[L_x(r)]^α(r), the coefficients A(r) and α(r) are scale-invariant; (2) The relation y(r) = 10^A(r)[L_x(r)]^α(r) given by cells containing collapsed objects is also available for cells without collapsed objects, only if r is larger than the dissipation scale. These two predictions are well established with a scale decomposition analysis of observed data, and a comparison of observed y(r) ? L_x(r) relation with hydrodynamic simulation samples. The implication of this result on the characteristic scales of non-gravitational heating is also addressed.     

砂岩型铀矿地震勘探方法技术研究

本文从野外工作方法、计算机数据处理技术、解释推断方法等方面,指出了在砂岩型铀矿地震勘探方法技术所应当注意的问题。用实例说明综合多种参数拾取砂体的工作方法与技术。同时说明,用补层加权法（ＷＭＯＣＢ）求取层速度,提高了解释推断的精度。     

Study on model for remote sensing estimation of maize yield

Through analysis of perpendicular vegetation index (PVI) from combination of visible and near-infrared spectrums reflecting the feature of crop reflectance, we come to the conclusion that the index can better indicate crop instantaneous photosynthesis whereas people generally regard it as the representation of crop leaf area index (LAI). Exploration of crop photosynthesis within a day and its period of duration leads to production of photosynthetic vegetation index (PST) that can reflect the whole crop accumulated photosynthesis, which means the total biomass produced by crop, moreover the method simulating PST is put forward by employment of multi-temporal spectrum parameters. On the basis of the achievements mentioned above, a new comprehensive model for remote sensing estimation of maize yield is established, which can comprehensively show major physiological actions of maize and the course of its yield formation, organically integrate various effective ways of crop yield estimation. It lays a solid foundation for carrying out remote sensing estimation of maize yield on a large scale.     

四川盆地南北缘志留系的锶和碳、氧同位素演化及其地质意义

通过对四川盆地北缘广元地区及南缘綦江地区上奥陶统及下志留统地层的８７Ｓｒ／８６Ｓｒ、δ１３Ｃ及δ１８Ｏ的系统测定,取得了沿地层剖面变化的同位素组成规律。研究结果表明,在盆地南缘８７Ｓｒ／８６Ｓｒ值高于地质历史中海水的平均值,其原因是本区为受板块内古陆控制的缓坡环境,大量陆源锶的混入增加了８７Ｓｒ／８６Ｓｒ的值。８７Ｓｒ／８６Ｓｒ值在上奥陶统至下志留统地层交界处、Ｒｈｕｄｄａｎｉａｎ／Ａｅｒｏｎｉａｎ（鲁丹期／艾隆期）交界处具正峰波动,反映了此时海平面的短时下降。但从Ｒｈｕｄｄａｎｉａｎ至Ｔｅｌｙｃｈｉａｎ（特里奇期）,８７Ｓｒ／８６Ｓｒ逐渐降低。从Ａｅｒｏｎｉａｎ至Ｓｈｅｉｎｗｏｏｄｉａｎ（舍因伍德期）早期,盆地南北缘的δ１３Ｃ值处于逐渐上升的过程之中,而δ１８Ｏ则相反。同位素的演化特征说明本区当时为海进时期,海平面不断上升,与全球性海平面变化相吻合。由于受区域构造运动的作用,Ｓｈｅｉｎｗｏｏｄｉａｎ之后的全球持续海进对本区无影响。     

云南泸沽湖矿物学沉积记录及其环境辨识意义

通过对泸沽湖矿物学沉积记录的精细剖析发现，泸沽湖的物质沉积过程相对稳定，沉积物粒度分布、矿物组成与组合沉积记录在纵向上的变化均具明显的韵律性，矿物结构与化学沉积记录也表现出规律性的变化特点。在泸沽湖上述矿物学沉积记录的典型特征基础上，通过对这些记录的环境标志性特征、环境辨识可适性等的探索性研究，在200，100和50a短时间尺度上，比较准确地重建了泸沽湖区域气候与环境演化的历史谱系，探讨了全球性气候因子对泸沽湖区域气候与环境变迁的控制     

Self-similar fractal analysis of gold mineralization of Dayingezhuang disseminated-veinlet deposit in Jiaodong gold province,China

The mineralization degree in drifts in the Dayingezhuang disseminated-veinlet gold deposit in Jiaodong gold Province, China, can be categorized into non-mineralized, weakly mineralized, moderately mineralized and intensely mineralized ranks based on the number of the gold grades greater than cut-off. The grades sampled equidistantly and continuously along different drifts at − 140 m, − 175 m and − 210 m levels of the deposit are systematically calculated via the self-similar fractal model. The grade distributions often show bifractal characteristics, including two or three non-scale ranges. It shows that with the increase of mineralized rank, the fractal dimension of the second non-scale range decreases and the corresponding threshold becomes greater. The dimension decrease comes from the increase of proportion of the wider microfracture in the ore-controlling structure system; and the threshold increase is a result from the magnitude elevation of the microfractures from the extension-shear zone to compression-shear zone. The smaller fractal dimension means the proportion of the higher gold grades increases, suggesting the thickness of the orebody is proportional to its mean gold grade.