构建“有深度”数学课堂,引导深度学习发生——以“正弦定理”教学为例

课堂作为数学课程实施的主要阵地,担负着发展学生数学学科核心素养的重要任务。在中学数学课堂教学中,教师可以通过情境激趣、问题驱动、体验积淀、道理感悟等方式,引领“情境—问题”教学,构建“有深度”数学课堂,引导深度学习发生。

追求“有深度”的数学教学

“有深度”的数学教学不仅指“数学深度”，而且包括“儿童深度”和“教学深度”。数学丰蕴的思想方法和儿童数学生命的生长呼唤“有深度”的数学教学。在儿童数学教学实践中，教师可以引领儿童探究数学知识核心，掌握知识本质，领悟知识背后的数学思想、方法和文化精神！

医学生“三有”外语课程思政及其教学实践路径

从思政课程到“课程思政”,是落实立德树人根本任务的要求,是时代赋予高校的新使命.高校应坚持以立德为根本,以树人为核心,充分发挥各门课程的育人功能.外语课程的特殊性以及医学生外语学习的工具性需要有高度、有深度、有温度的外语课程思政.外语课程思政要通过完善课程教学计划以强化高度,加强师资队伍建设以扩展深度,优化教学模式以提升温度.思政教育只有实现从“专人”向“人人”的创造性转化,真正做到显性教育与隐性教育有效贯通,才能真正落到实处.

EFFECTIVE DETECTION DEPTH OF NEEDLE-LIKE OPTICAL PROBE

The effective detection depth of the needle-like optical probe is studied. The light transport model in highly scattering tissue is the diffusion equation and the boundary is Neuman. The sensitivity matrix is related to the position of the light source and the detector. It can be used to evaluate the effective detection depth. The sensitivity matrix is defined as the multiplication of the source and detector hght distribution. Six different groups about ix parameters including the source diameter and detector fibers, the core-to-core distance between the source and detector fibers, the opotode depth, the absorption, and reduced scattering coefficient, are used as experimental models. The relationship between the six parameters and the effective detection depth is analyzed. Resuits can be used to study the spatial resolution and the depth of multi-fibers.

Accelerating f inite difference wavef ield-continuation depth migration by GPU

The most popular hardware used for parallel depth migration is the PC-Cluster but its application is limited due to large space occupation and high power consumption. In this paper, we introduce a new hardware architecture, based on which the finite difference （FD） wavefield-continuation depth migration can be conducted using the Graphics Processing Unit （GPU） as a CPU coprocessor. We demonstrate the program module and three key optimization steps for implementing FD depth migration： memory, thread structure, and instruction optimizations and consider evaluation methods for the amount of optimization. 2D and 3D models are used to test depth migration on the GPU. The tested results show that the depth migration computational efficiency greatly increased using the general-purpose GPU, increasing by at least 25 times compared to the AMD 2.5 GHz CPU.

Depth Classification of Underwater Targets Based on Complex Acoustic Intensity of Normal Modes

In order to solve the problem of depth classification of the underwater target in a very low frequency acoustic field, the active component of cross spectra of particle pressure and horizontal velocity （ACCSPPHV） is adopted to distinguish the surface vessel and the underwater target. According to the effective depth of a Pekeris waveguide, the placing depth forecasting equations of passive vertical double vector hydrophones are proposed. Numerical examples show that when the sum of depths of two hydro- phones is the effective depth, the sign distribution of ACCSPPHV has nothing to do with horizontal distance; in addition, the sum of the first critical surface and the second critical surface is equal to the effective depth. By setting the first critical surface less than the difference between the effective water depth and the actual water depth, that is, the second critical surface is greater than the actual depth, the three positive and negative regions of the whole ocean volume are equivalent to two positive and negative regions and therefore the depth classification of the underwater target is obtained. Besides, when the 20 m water depth is taken as the first critical surface in the simulation of underwater targets （40 Hz, 50 Hz, and 60 Hz respectively）, the effectiveness of the algorithm and the cor- reemess of relevant conclusions are verified, and the analysis of the corresponding forecasting performance is conducted.

Empirical formula for wave length of ocean wave in finite depth water

In this paper, function characteristics of dispersion of ocean wave in finite depth water were analyzed systematically. The functional form of the fitting function is reasonably proposed, in which the parame- ters are optimally determined by the least square method (LSM). For infinitely deep and extremely shallow water, the fitting function fits strictly the dispersion to be fitted. A new technique is presented in application of LSM. An empirical formula with maximum error of less than 0.5% for computing wavelength in finite depth water is presented for practical applications.

Relationship between rectification moment and angle of shield based on numerical simulation

The finite element method is used to simulate the rectification process of shield machine, to study the relationship between rectification moment and angle and to explore the influence laws of different soil parameters and buried depth on rectification moment. It is hoped that the reference value of rectification moment can be offered to operator, and theoretical foundation can be laid for future automatic rectification technology. The results show that the rectification moment and angle generally exhibit good linear behavior in clay layers with different soil parameters or buried depths, and then the concept of rectification coefficient, that is, the ratio of rectification angle to rectification moment, is proposed; different soil parameters and buried depths have different influences on rectification coefficient, in which elastic modulus has great influence but others have little influences; the simulations of rectification process are preformed in clay layers with different elastic modulus, and fitting results show that elastic modulus and rectification coefficient present the quadratic function relation.

Soil Nutrient Variance by Slope Position in a Mollisol Farmland Area of Northeast China

In order to generate scientifically-based comparative information to improve fertilization efficiency and reduce nutrient loss, 610 samples of 122 soil profiles were collected at the 0–60 cm depth to compare soil nutrient contents including soil organic matter(SOM), total nitrogen(TN), total phosphorus(TP), available phosphorus(AP), and available potassium(AK) among different slope positions in a Mollisol farmland area of Northeast China. The contents of SOM and TN typically decreased with increased soil depth at back and bottom slope. Soil loss and deposition tended to decrease SOM and TN at the 0–20 cm soil depth on both the back slope and the slope bottom. The TP firstly decreased from 0–20 cm to 30–40 cm, and then not constantly increased at the back slope and the bottom slope. Due to the characteristics of soil nutrients and crop absorption, the contents of both AP and AK were typically the highest at the summit, followed by the slope bottom and the back slope in the 0–20 cm layer. Generally, in order to sustain the high soil productivity and protect the environment, attention should be paid to soil conservation on back slope; in addition, additional N and P fertilizer is necessary on the back slope.

Numerical Investigation of Transmission of Low Frequency Sound Through a Smooth Air-water Interface

It is the traditional belief that sound transmission from water to the air is very weak due to a large contrast between air and water impedances. Recently, the enhanced sound transmission and anomalous transparency of air-water interface have been introduced. Anomalous transparency of air-water interface states that the sound generated by a submerged shallow depth monopole point source localized at depths less than 1/10 sound wavelength, can be transmitted into the air with omni-directional pattern. The generated sound has 35 times higher power compared to the classical ray theory prediction. In this paper, sound transmission through air-water interface for a localized underwater shallow depth source is examined. To accomplish this, two-phase coupled Helmholtz wave equations in two-phase media of air-water are solved by the commercial finite element based COMSOL Multiphysics software. Ratios of pressure amplitudes of different sound sources in two different underwater and air coordinates are computed and analyzed against non-dimensional ratio of the source depth （D） to the sound wavelength （λ）. The obtained results are compared with the experimental data and good agreement is displayed.

Removal of TOC and Color in Bleaching Effluents from Straw Pulp and Paper Mill by Fe^0-H_2O_2 Process

TOC and color in the bleaching effluent from straw pulp paper process could not reach draining standard after its treatment by a biochemical process. In this study, advanced treatment by integrated micro-electrolysis （Fe^0） method and Fenton-like process was investigated under various conditions, i.e. pH, Fe/C ratio, initial I-I2O2 concentration and carrier gas. Results showed that Fe/C ratio（V/V = 1.5）, larger H2O2 dosage around 50 rag/L, lower pH（pH= 3） turned out to be particularly efficient. Temperature was a key parameter, remarkably increasing reaction rates. Carrier air not only improved reaction efficiency, but also saved H2O2 dosage. Chlorinated organic compounds could be reductive dechlorinated by Fe^0 reaction and oxidated by OH produced from Fenton process. The combination of Fe^0 and H2O2 reactions had been proved to be highly effective for the advanced treatment of such a type of wastewaters, and important advantages concerning the application in the study.

Failure mechanism of large-diameter shield tunnels and its effects on ground surface settlements

A new technique for the analysis of the three-dimensional collapse failure mechanism and the ground surface settlements for the large-diameter shield tunnels were presented.The technique is based on a velocity field model using more different truncated solid conical blocks to clarify the multiblock failure mechanism.Furthermore,the shape of blocks between the failure surface and the tunnel face was considered as an entire circle,and the supporting pressure was assumed as non-uniform distribution on the tunnel face and increased with the tunnel embedded depth.The ground surface settlements and failure mechanism above large-diameter shield tunnels were also investigated under different supporting pressures by the finite difference method.

SIMULATION AND OPTIMIZATION FOR THERMAL SYSTEM IN GROUND ARTIFICIAL FREEZING

The situation of mine development in coal industry of China and the method of shaft freezing in the type of double ring freezing pipe used for shaft sinking under thick alluvium condition are briefly reviewed. The equations of heat conduction are numerically solved for two kinds of artificial shaft freezing-sin-gle and double ring freezing pipe pattern. A two-dimensional finite difference model simulating the temperature field is developed. The paper introduces a way to calculate the harmonic mean of heat conductivety used when dealing with heterogeneous material, The theoretically derived temperature distributions in frozen soil are given and the comparison is made between two types of freezing pipe arrangement. The optimization technique of a general simulation is discussed, and that is in use to improve the thermal system in shaft freezing.

Long-Term Effect of Industrial Waste Water Irrigation on Soil Chemical Properties

A laboratory experiment was conducted in Soil Science Division of BRRI during 2011 aimed to determine the vertical distribution of soil chemical properties under long-term industrial waste water irrigated rice field. Waste water irrigated rice field seemed to create some differences in soil pH profile. The pHW and pHKCl in all soil depth was higher with waste water irrigated rice field. The surface charge of both the soils was considerably negative. Waste water irrigated rice field developed more negative charges in soils. Irrigation with waste water increased Electrical Conductivity （EC） in rice soils profile. The organic carbon content （%） started to decrease sharply with the increase in soil depth. Organic carbon content was higher with waste water irrigated rice soils Total nitrogen （%） was high with underground water irrigated rice soils in surface but at deeper, total N was similar in both soils. Olsen P （mg/kg） was higher with underground water irrigated soil at 0-5 cm depth but at 5-100 cm soils profile, it was higher with waste water irrigated rice soils. Micronutrients （Zn, Fe, Cu and Mn） and heavy metals （Pb, Cd, Ni and Cr） in soils were increased significantly through irrigation with waste water in rice-rice cropping pattern.

Study on optimization of underlying coal bed exploited depth for tunnel

Combined with highway construction, the analysis on the relationship betweentunnel construction and coal resource exploitation was processed, which was based onthe research of rational exploitation depth of coal.3D FEM numerical analysis for tunnelexcavation was carried out according to engineering geological features of coal measurestrata in the project area.Based on the analysis of displacement and stress of the surroundingrock in the tunnel after excavation, the characteristics for displacement andstress of the tunnel support structure were analyzed when the underlying coal bed wasexploited with sublevel and full caving method.In addition, combined with the related codeand standard, the economic and safe prohibiting exploited depth of the underlying coalbed was proposed, so that a scientific basis for tunnel construction of coal measure strataand reasonable exploitation of the mineral resources in complex geological conditions canbe offered.

Spatiotemporal Variations of Soil Microarthropod Communities in the Negev Desert

Desert ecosystems are characterized by sparse vegetation that affects both abiotic parameters and soil biota along the soil profile. This study was conducted in 2010-2011 in a loess plain in the northern Negev Desert highlands, Israel, to test two main hypotheses： 1） the abundance and diversity of microarthropods would vary seasonally in the top 30-cm soil layer, but would be relatively stable at soil depths between 30 and 50 cm and 2） soil microarthropods would be more abundant in soils under shrubs with large litter accumulations than under shrubs with less litter or bare soil. Soil samples were collected each season from the 0-50 cm profile at 10-cm intervals under the canopies of Hammada scoparia and Zygophyllum dumosum and from the bare interspa^es between them. Soil moisture and soil organic carbon in the top 30-cm layers varied seasonally, but there was little variation in the soil layers deeper than 30 cm. Soil mites were most abundant in the top 30-cm soil layer in autumn and winter, with the highest number of families found in winter. There were no differences in soil microarthropod abundance attributable to the presence or absence of shrubs of either species. The microarthropod communities of the microhabitats studied consisted of Acari, Psocoptera, and Collembola. The Acari were mostly identified to the family level and were dominated by Oribatida （55%） and Prostigmata （41%） in all seasons and microhabitats, while the psocopterans were most abundant in summer. These results are opposite to those obtained in other studies in similar xeric environments. Moreover, our findings were not in line with our hypothesis that a better microhabitat played a major role in microarthropod community composition, diversity, and density.

High-brightness blue organic light emitting diodes with different types of guest-host systems

We demonstrate high-brightness blue organic light emitting diodes(OLEDs) using two types of guest-host systems. A series of blue OLEDs were fabricated using three organic emitters of dibenz anthracene(perylene), di(4-fluorophenyl) amino-di(styryl) biphenyl(DSB) and 4,4'-bis[2-(9-ethyl-3-carbazolyl)vinyl]biphenyl(BCzV Bi) doped into two hosting materials of 4,4'-bis(9-carbazolyl) biphenyl(CBP) and 2-(4-biphenylyl)-5(4-tert-butyl-phenyl)-1,3,4-oxadiazole(PBD) as blue emitting layers, respectively. We achieve three kinds of devices with colors of deep-blue, pure-blue and sky-blue with the Commission Internationale de L'Eclairage(CIE) coordinates of(0.16, 0.10),(0.15, 0.15) and(0.17, 0.24), respectively, by employing PBD as host material. In addition, we present a microcavity device using the PBD guest-host system and achieve high-purity blue devices with narrowed spectrum.