黄山北麓青弋江发育原因及其与长江贯通的关系

基于前期研究工作成果和外部环境变化因素分析,探讨了青弋江发育原因及其与长江贯通的关系。研究表明：① 昆黄运动可能在长江中下游地区产生了区域构造响应,导致研究区断层被激活而发生了较大幅度的断块抬升运动,进而为青弋江发育提供了下切驱动力,驱动了青弋江发育;② 东亚夏季风在约1.3 Ma和约0.9 Ma发生的2次显著阶段性减弱事件,引起区域降水量显著增加,进而为青弋江发育提供了下切媒介和持续水流,控制了青弋江发育年代;③ 青弋江发育与长江贯通可能都是昆黄运动区域构造响应与东亚夏季风强度阶段性减弱共同作用的结果,并且长江贯通后所形成的新局部侵蚀基准面也可能促进了青弋江发育,因此青弋江发育年代在一定程度上能反映长江贯通年代。     

浅谈义务教育地理审美情趣及审美化教学

地理审美情趣是人文底蕴的重要因素,也是义务教育阶段地理课程目标的重要组成,是在观察地理现象美、探索地理理论美、感悟地理哲学美的过程中发展起来的。审美直觉感兴力、审美趣味和审美态度的形成是地理审美情趣发展成熟的标志。审美化教学是把地理德育、智育寓于地理美育之中,以美引善、以美导真、以美生情、以美育美的教学方式,具有体验性、娱乐性、自主性特征,地理教师以发现式教学、问题式教学、活动性教学为路径,引导学生探寻地理审美源泉,启思地理审美过程,涵养地理审美情趣。     

5G网络下运用虚拟仿真实验教学培养地理核心素养——以“土壤”为例

5G网络的推行为高中地理教育提供了更加多样的内容和形式。本文通过以网络为依托的“庐山人工针叶林生态系统调查与保护虚拟仿真”实验,结合常规课堂教学,实现“以虚补实”“虚实结合”的教学目标,有助于提高课堂教学效率,培养地理学科核心素养。     

Dynamic features of near-inertial oscillations in the Northwestern Pacific derived from mooring observations from 2015 to 2018

Near-inertial oscillation is an important physical process transferring surface wind energy into deep ocean.We investigated the near-inertial kinetic energy(NIKE) variability using acoustic Doppler current profiler measurements from a mooring array deployed in the tropical western Pacific Ocean along130°E at 8.5°N,11°N,12.6°N,15°N,and 17.5°N from September 2015 to January 2018.Spatial features,decay timescales,and significant seasonal variability of the observed NIKE were described.At the mooring sites of 17.5°N,15°N,and 12.6°N,the NIKE peaks occurred in boreal autumn and the NIKE troughs were observed in boreal spring.By contrast,the NIKE at 11°N and 8.5°N showed peaks in winter and troughs in summer.Tropical cyclones and strong wind events played an important role in the emergence of high-NIKE events and explained the seasonality and latitudinal characteristics of the observed NIKE.     

Local-scale patterns of genetic variation in coexisting floating-leaved Nymphoides peltata and submerged Myriophyllum spicatum in Donghu Lake

Journal of Oceanology and Limnology - Coexisting floating-leaved and submerged plants experience similar environmental changes but may evolve different patterns of genetic variation. To compare...     

A Novel Approach for Evaluating Nonstationary Response of Dynamic Systems to Stochastic Excitation

The transient state of a dynamic system, such as offshore structures, to random excitation is always nonstationary. Many studies have contributed to evaluating response covariances at the transient state of a linear multi-degree-of-freedom(MDOF) system to random excitations, but a closed-form solution was not available unless the excitation was assumed to be a physically unrealizable white noise process. This study derives explicit, closed-form solutions for the response covariances at the transient state by using a pole-residue(PR) approach operated in the Laplace domain when the excitations are assumed to be stationary random processes described by physically realizable spectral density functions. By using the PR method, we can analytically solve the triple integral in evaluating the nonstationary response covariance. As this approach uses the poles and residues of system transfer functions, rather than the conventional mode superposition technique, the method is applicable to MDOF systems with non-classical damping models. Particular application of the proposed method is demonstrated for multi-story shear buildings to stochastic ground acceleration characterized by the Kanai–Tajimi spectral density function model, and a numerical example is provided to illustrate the detailed steps. No numerical integrations are required for computing the response covariances as the exact closed-form solution has been derived. The correctness of the proposed method is numerically verified by Monte Carlo simulations.     

莱州湾早全新世高黏粒软土工程地质特征及岩相古地理

依据工程地质调查、土工试验、~(14)C测年及古生物鉴定,从莱州湾滨海地区的早全新世高黏粒软土中识别出3种古地理沉积环境。分析发现,软土黏粒含量高、呈暗色调,属埋藏型。颗粒级配、压缩模量等物理力学指标差异则指示了同期异相沉积软土的工程地质特征。采取Q型聚类分析,将莱州湾早全新世高黏粒软土划分为下三角洲相沉积软土、潮平相沉积软土、湖沼相沉积软土。通过统计分析,掌握了滨海区软土工程地质特性,为合理选取土工试验参数提供沉积学依据,为合理利用天然地基提供参考。     

A two-step ionospheric modeling algorithm considering the impact of GLONASS pseudo-range inter-channel biases

The Global Navigation Satellite System presents a plausible and cost-effective way of computing the total electron content (TEC). But TEC estimated value could be seriously affected by the differential code biases (DCB) of frequency-dependent satellites and receivers. Unlike GPS and other satellite systems, GLONASS adopts a frequency-division multiplexing access mode to distinguish different satellites. This strategy leads to different wavelengths and inter-frequency biases (IFBs) for both pseudo-range and carrier phase observations, whose impacts are rarely considered in ionospheric modeling. We obtained observations from four groups of co-stations to analyze the characteristics of the GLONASS receiver P1P2 pseudo-range IFB with a double-difference method. The results showed that the GLONASS P1P2 pseudo-range IFB remained stable for a period of time and could catch up to several meters, which cannot be absorbed by the receiver DCB during ionospheric modeling. Given the characteristics of the GLONASS P1P2 pseudo-range IFB, we proposed a two-step ionosphere modeling method with the priori IFB information. The experimental analysis showed that the new algorithm can effectively eliminate the adverse effects on ionospheric model and hardware delay parameters estimation in different space environments. During high solar activity period, compared to the traditional GPS + GLONASS modeling algorithm, the absolute average deviation of TEC decreased from 2.17 to 2.07 TECu (TEC unit); simultaneously, the average RMS of GPS satellite DCB decreased from 0.225 to 0.219 ns, and the average deviation of GLONASS satellite DCB decreased from 0.253 to 0.113 ns with a great improvement in over 55%.     

基于游客认同的文化遗产景区安全标识系统研究——以青城山-都江堰景区为例

文化遗产景区安全标识系统作为传播信息和规范观赏行为的有效方式,已成为影响游客旅游体验和衡量景区服务水准的重要因素。借助实地考察与随机抽样问卷调查,以青城山-都江堰世界文化遗产景区为例,综合利用文献分析和数理统计验证,拟定11项安全标识测量指标以调查游客对景区安全标识系统的认同感,研究结果表明:游客普遍认同遗产景区安全标识系统的重要性,但多是从利己角度的直观考虑;游客对青城山-都江堰文化遗产景区安全标识系统认同度低,安全标识系统各构成要素急需改进,尤其是安全标识的设计和功能;游客对文化遗产景区安全标识系统的认同度并不完全受人口统计特征影响;游客对文化遗产景区安全标识系统的认同度受游客出游频率和旅游形式影响。建议文化遗产景区从完善安全标识布局和基本功能、强调景观感设计、规范安全标识系统文字和色彩、改进标识的视觉尺寸和开展定期检查维护方面实施优化。