培育志趣，引导学生奔向地球科学大道

随着人类社会和科学技术的发展,尤其是中国国力的提升和教育的深化提高,教育改革,包括地学高等教育的改革,就更需进一步深化,以适应时代发展的需要。文章根据作者长期从事地学教学实践与科研的经历,针对2020年全国基础地质学教学会议关于普通地质学教学改革的精神,概括提出两点体会,一是关于普地教学目标和任务,二是涉及普地教学关键所在,供同行讨论。作者从地球科学基本特征和教学目标出发,提出普地教学的核心价值与重要性,进一步明确普地教学的关键在于教师队伍、教学定位与目标及教学内容与方法等三个方面。普通地质学的教学是地学高等教育中最基础、最关键的环节,其总体目标是提高地学教育的普适性,目的是培育学生的科学志趣,引导学生奔向地球科学大道。     

初始主应力方向对钙质砂动力特性影响的试验研究

利用大连理工大学的土工静力-动力液压三轴-扭转动多能剪切仪对相对密度为30 %的钙质砂进行了扭转和竖向循环耦合试验,探讨了初始主应力方向角 对钙质砂动强度和残余应变发展的影响。试验结果表明： 对钙质砂的动强度、残余应变发展的影响非常明显,随着 的增大,钙质砂的动强度显著减小,而残余应变的发展速度则明显加快。     

Statistical data fusion of multi-sensor AOD over the Continental United States

This article illustrates two techniques for merging daily aerosol optical depth (AOD) measurements from satellite and ground-based data sources to achieve optimal data quality and spatial coverage. The first technique is a traditional Universal Kriging (UK) approach employed to predict AOD from multi-sensor aerosol products that are aggregated on a reference grid with AERONET as ground truth. The second technique is spatial statistical data fusion (SSDF); a method designed for massive satellite data interpolation. Traditional kriging has computational complexity O(N³), making it impractical for large datasets. Our version of UK accommodates massive data inputs by performing kriging locally, while SSDF accommodates massive data inputs by modelling their covariance structure with a low-rank linear model. In this study, we use aerosol data products from two satellite instruments: the moderate resolution imaging spectrometer and the geostationary operational environmental satellite, covering the Continental United States.     

两种不同凝胶柱测定壳聚糖分子量结果的比较

凝胶渗透色谱法测定壳聚糖分子量 ,以葡聚糖为标准品 ,用 2种不同的凝胶柱 (PLaquagel- OH柱和 TSK G4 0 0 0 PWXL柱 )测定 4种样品的分子量及其分布 ,并经过普适标定。比较结果发现 :PL aquagel- OH柱效果稍好于 TSK G4 0 0 0 PWXL柱。两柱所得重均分子量平均偏差为 0 .17%～ 3.38% ,数均分子量的平均偏差为 0 .90 %～ 3.5 7% ,分子量分布宽度指数 1.34～ 1.5 4。     

A model for wave growth in fetch-limited conditions

In this paper, it is held that the universal relationships of wave growth in fetch-limited conditions , i. e.,(f|~) p=A(x|~)-Band (m|~)0= C(x|~) Dshould satisfy the Toba 3/2 power law and the wave energy balance equation. In the ideal generation situation, theoretically it can be derived that the ideal fetch-limited wave growth relationship should have D=3B and D B =1, (i.e., B = 0.25, D = 0.75 ) and A3C=2. 1×l(T4C~(1/2)_d , where Cd is the drag coefficient. The 3/2 power law, the wave energy balance equation and the decrease of wave steepness with increasing fetch have became three requirements which should be satisfied by fetch-limited wave growth algorithms. A semi-empirical and semi-theoretical model for fetch-limited wave growth is presented. In the application to the slanting wind situation an un(?)ersal relationship of dimensionless wave energy vs dimensionless peak frequency is presented and the comparisons show that the model is in good agreement with observations.     

格上泛滤敛关系的公理刻划及其与泛邻元系之间的等价性

汪培庄提出了格的相对尾的概念,并在此基础上建立了格的泛邻元结构。作者进一步讨论了格的相对尾的性质,并在此基础上给出了格上泛滤敛关系的公理刻划,证明了格上泛滤敛关系与泛邻元系之间的等价性。     

Ephemrides of visual binaries in universal variables

In this paper, universal formulations of the two‐body problem are established for ephemerides of visual binary systems, whatever the type of their orbits may be. A computational algorithm is also given and applied to the binaries ADS 9159, ADS 2959 and ADS 11632 as typical examples of elliptic, parabolic and hyperbolic binaries, respectively.     

Multidimensional social trust and regional entrepreneurial activities: Based on data from the China Family Panel Studies (CFPS)北大核心CSCD

社会信任作为非正式制度环境的核心构成要素对区域创业活动有复杂而重要的影响。由于社会距离、交往对象的不同,社会信任在表现形式和作用机制方面差异明显,但现有研究鲜有关注社会信任不同维度对区域创业的影响。论文从普遍信任、亲缘信任、制度信任3个维度构建社会信任框架,利用中国家庭跟踪调查(CFPS)2012、2014、2016、2018年4期面板数据和企业工商注册信息微观数据进行实证分析,研究发现：(1)在全国尺度,亲缘信任显著提高了区域创业活跃度,而普遍信任、制度信任对区域创业活跃度的作用不明显。(2)交互效应结果显示,普遍信任、亲缘信任与经济发展之间存在替代效应;普遍信任与政府干预互为补充,政府干预越弱,普遍信任对区域创业的激励作用越强;而制度信任与政府干预表现为相互促进的互动关系,共同促进了区域创业活跃度。(3)分样本异质性检验表明,东部地区创业活跃度对社会信任的依赖度较弱;中西部地区创业活跃度受到普遍信任、亲缘信任的积极影响;政商关系良好城市的创业活跃度受到制度信任的促进作用,创业政策红利得到有效释放;在政商关系普通城市,普遍信任能够显著促进创业,激发创业活力。研究证实了不同维度社会信任...     

基于SCS和USLE的程海总磷总氮参照状态推断

将流域入湖的氮磷负荷分为点源和非点源两部分,基于SCS模型和USLE模型,分别计算流域入湖的溶解态和颗粒态非点源负荷,根据工业、城镇生活及规模养殖废水排放,计算了流域入湖的点源负荷。通过计算的入湖负荷和现有的湖泊氮磷浓度数据,建立了湖泊氮磷质量守恒模型。根据计算的逐年入湖氮磷负荷和建立的湖泊氮磷质量守恒模型,逆推逐年的湖泊氮磷浓度,确定湖泊氮磷参照状态。应用建立的模型推断程海的TP、TN参照状态分别为0.014 mg/L和0.247 mg/L。构建的湖泊氮磷参照状态推断模型,所需资料少,概念清晰,在资料缺乏的其他湖泊流域具有推广应用价值。     

华北地层大区东南区寒武纪早期地层对比与统一划分

华北地层大区东南区的寒武纪早期地层 ,宜统一划分为6个三叶虫化石带(Shantungaspis,Yaojiayuella ,Qiaotouaspis,Redlichia(Pteroredlichia) ,Megapalaeolenus和Hsuaspis)和3个组(毛庄组、馒头组和猴家山组)。毛庄组包含Shantungaspis带 ,Yaojiayuella带和Qiaotouaspis带一部分 ,馒头组包含Qiaotouaspis带大部分、Redlichia(Pteroredlichia)带和Megapaeolenus带 ,猴家山组仅含Hsuapis带。前2带属毛庄阶 ,第3、4带属龙王庙阶 ,后2带属沧浪铺阶。中、下寒武统界线划在毛庄阶与龙王庙阶即Yaojiayuella带与Qiaotouaspis带之间。毛庄组属下—中寒武统 ,其它2组属下寒武统。按各组的岩层组合特征 ,统一划分为15个岩性段