集成U-Net方法的无人机影像胡杨树冠提取和计数

塔里木河流域的胡杨林是该荒漠区域典型的森林资源，胡杨树冠大小和株数信息对塔里木河流域森林资源监测、生态保护和恢复具有重要意义。由于该流域乔灌草植物群落分布的复杂性，传统方法很难实现胡杨树冠的精准分割和大范围的株数提取。以塔里木河中游胡杨林为研究区，选取几块典型胡杨林区域，提出集成深度学习和分水岭分割的处理方法，对密集胡杨树冠的精准分割和单株胡杨的提取进行了深入探讨。首先，将无人机影像（空间分辨率0.16 m）无缝拼接生成正射影像；采用U-Net卷积神经网络对胡杨树冠覆盖区域进行精准分割；在U-Net模型分割的基础上使用标记分水岭方法对密集胡杨树冠进行自动再分割和单株计数，计算出所选研究区的胡杨株数并精准定位。结果表明U-Net卷积神经网络对胡杨的所有树冠区域提取的平均精度可达94.1%，在胡杨树冠覆盖区域识别分割的基础上，用标记分水岭分割方法对胡杨单木计算总体精度为93.3%。研究认为，结合深度学习和标记分水岭方法为自动化大范围森林资源监测提供了新思路和借鉴经验。     

Radio Resource Allocation in Multi-User Cooperative Relaying Networks with Resource Block Pairing and Fairness Constraints

In this paper we address the problem of radio resource allocation in cooperative relaying networks. We focus on the resource block and power allocations for the downlink of OFDM-based relaying multi-user network. The resource allocation is investigated for both amplify and forward and decode and forward protocols under the constraints of power, resource block pairing and data rate fairness. To reduce complexity, the optimization problem is solved in two steps. In the first step, resource block pairing and allocation are conducted jointly with equal transmission power for both the base station and the relay. In the second step, transmission power is further optimized to maximize the system throughput. Our analysis is focused on the total achievable system throughput and the achievable individual throughput for each user.     

Single‐Crystalline p‐Type Zn3As2 Nanowires for Field‐Effect Transistors and Visible‐Light Photodetectors on Rigid and Flexible Substrates

Zn₃As₂ is an important p‐type semiconductor with the merit of high effective mobility. The synthesis of single‐crystalline Zn₃As₂ nanowires (NWs) via a simple chemical vapor deposition method is reported. High‐performance single Zn₃As₂ NW field‐effect transistors (FETs) on rigid SiO₂/Si substrates and visible‐light photodetectors on rigid and flexible substrates are fabricated and studied. As‐fabricated single‐NW FETs exhibit typical p‐type transistor characteristics with the features of high mobility (305.5 cm² V^?1 s^?1) and a high I_on/I_off ratio (10⁵). Single‐NW photodetectors on SiO₂/Si substrate show good sensitivity to visible light. Using the contact printing process, large‐scale ordered Zn₃As₂ NW arrays are successfully assembled on SiO₂/Si substrate to prepare NW thin‐film transistors and photodetectors. The NW‐array photodetectors on rigid SiO₂/Si substrate and flexible PET substrate exhibit enhanced optoelectronic performance compared with the single‐NW devices. The results reveal that the p‐type Zn₃As₂ NWs have important applications in future electronic and optoelectronic devices.     

特厚煤层综放开采地表沉陷规律实测研究

为研究近浅埋深、中厚基岩、特厚煤层综放开采地表沉陷规律,在东坡煤矿914工作面地表建立地表移动观测站进行了观测。经对测得的数据分析,得到一套完整的地表沉陷预计参数和角量参数,分析了该地质采矿条件下角量参数与动态变形特征。结果表明:东坡煤矿下沉系数、水平移动系数、主要影响角正切、开采影响传播角分别为0.74、0.25、2.95、86.5°;在特厚煤层综放开采条件下,地表移动的初始期较短,活跃期内地表下沉速度大,移动剧烈,地表下沉量占总下沉量的比例大。在近浅埋深、中厚基岩条件下,特厚煤层综放开采地表沉陷规律具有其特殊性。     

三山岛金矿床流体包裹体研究

三山岛金矿床位于胶东西北部,属于典型的"焦家式"(破碎带蚀变岩型)金矿床。对矿区内主成矿阶段石英中的流体包裹体进行了岩相学、显微测温、氢氧同位素及单个包裹体成分激光拉曼光谱研究。研究表明,矿石中流体包裹体主要有纯CO2单相包裹体、气液二相包裹体和含CO2三相包裹体3种类型;矿石石英中流体包裹体普遍富含CO2;成矿过程中,流体经历了CO2-Na Cl-H2O体系的不混溶作用;成矿流体具有低盐度(3.85%~11.60%)、低密度(0.70~0.96 g/cm3)的特点;主成矿温度集中为260~320℃,成矿压力范围为70~110 MPa,相应(成矿)深度范围为6.78~8.69 km。结合流体包裹体氢氧同位素分析认为,三山岛金矿床成矿流体以地幔流体为主,并有少量的岩浆流体。确定矿床成因类型为为幔源流体参与成矿的中温热液脉型金矿床。     

边缘检测属性应用方法

地震属性的解释可获取有关地层的断层、裂缝及岩性变化的重要特征信息。文中提出了边缘检测属性,该属性是利用图像处理中边缘检测方法对振幅属性进行处理得到的新地震属性,该属性可用于岩性识别。首先,通过实际的数学模型验证边缘检测方法识别边界的可行性及能力。利用几种经典的边缘检测方法。结合实际地震资料进行综合分析研究,发现Sobel属性能较好地突出属性图像的边界,砂岩与泥岩区得到区别,并得到了钻测井资料验证。在研究区的应用中,新属性可以较好地区分砂泥岩边界,减少了单一利用属性划分砂体造成的误差,对提高砂体识别精度以及勾绘砂体展布具有重要意义。     

颗粒基随钻堵漏钻井液流变参数测算方法

随钻堵漏材料的加入必然会对钻井液的流变性能产生影响。针对旋转黏度计标准测量间隙过窄而无法测量含粗粒堵漏材料钻井液流变性能的问题,利用实验测试与反问题数学模型相结合的方法,建立了颗粒基随钻堵漏钻井液的流变参数测算方法。利用建立的测算方法,将旋转黏度计的读数和转速数据转化为剪切应力与剪切速率形式。结果表明,建立的流变参数测算方法可靠性强,含颗粒随钻堵漏材料的KCl聚合物钻井液的流变曲线符合H-B模型,增加颗粒堵漏材料会显著影响钻井液流变参数。颗粒材料粒径和加量对钻井液的流变特性均有明显影响,测算随钻堵漏钻井液流变参数时应予以重视。     

微波合成纳米NaX分子筛的研究与表征

在常压回流微波加热条件下合成了NaX分子筛,并对其进行了XRD,FTIR,TEM,NMR表征,考察了合成配比对NaX分子筛的晶粒尺寸、形貌、硅铝比及相对结晶度的影响。表征结果显示,合成配比对NaX分子筛的晶粒尺寸、形貌、硅铝比及相对结晶度具有较为显著的影响。XRD和TEM表征结果显示,合成的NaX分子筛的晶粒尺寸为30¹00 nm。FTIR表征结果显示,当焙烧温度高于600℃时,纳米NaX分子筛的骨架开始崩塌,表明纳米NaX分子筛的热稳定性低于常规NaX分子筛。NMR表征结果显示,合成的纳米NaX分子筛具有较低的硅铝比,且硅物种配位峰的化学位移向高场偏移。微波合成的NaX分子筛的晶粒度明显小于常规合成的NaX分子筛,且晶化时间明显缩短,充分证明了微波加热快速均匀且能得到较小晶粒度的分子筛。     

甜菜果胶制备藻油乳化液及其稳定性研究

藻油富含对人体非常重要的多不饱和脂肪酸DHA（二十二碳六烯酸）,但其极易被光、热和氧等因素诱使发生氧化反应。防止氧化反应发生,制备成稳定的油／水乳化液将其包埋成为其在食品中应用的关键问题。本研究采用甜菜果胶为乳化剂对其进行乳化包埋,研究了乳化条件如乳化剂量、油水比率、pH和均质条件对乳化液稳定性的影响。结果表明,最适的乳化条件为：乳化剂添加量在2．5％以上,油水比1：10,pH〉5,35MPa压力下均质3个循环得到比较稳定的乳化液。     

Slowly digestible sweetpotato flour: Preparation by heat-moisture treatment and characterization of physicochemical properties

The preparation and physicochemical characteristics of sweetpotato flour with increased slowly digestible starch (SDS) fraction were investigated under various heat-moisture treatment (HMT) conditions. The optimum conditions for preparing slowly digestible sweetpotato flour established using response surface methodology were moisture content of 22%, temperature of 103°C, and treatment time of 5.8 h. The highest SDS content in heat-moisture treated sweetpotato flour was 57.6%. The relative crystallinity of heat-moisture treated sweetpotato flour decreased, but the X-ray diffraction pattern maintained the A-type. The DSC of the heatmoisture treated flour showed a decreased gelatinization temperature range and gelatinization enthalpy compared with native one. The viscosity profiles and values changed significantly with HMT, resulting in a higher pasting temperature, decrease of the viscosity values, and no breakdown. It indicates that heat-moisture treated sweetpotato flour is more stable at high temperatures and shear rates than native one.