覆盖和耕作对黄土高原冬小麦土壤入渗特性的影响

用人工模拟降雨器对黄土高原冬小麦收获后6个耕作措施:不翻耕(NT),不翻耕 覆盖(NTC),浅翻耕(LT),浅翻耕 覆盖(LTC),深翻耕(DT),深翻耕 覆盖(DTC)处理下土壤的入渗进行了研究,测定了土壤表面结皮、粗糙度等指标因子。结果表明,在模拟降雨强度为66 mm/h的条件下,覆盖处理的稳定入渗率>60 mm/h,降雨开始的40 m in内,平均入渗量>93%;深翻耕(DT)的稳定入渗率(26.4 mm/h)是浅翻耕(LT)(13.0 mm/h)的2倍,是不翻耕(NT)(6.4 mm/h)的4.1倍,降雨历时20m in时,深翻耕(DT)和浅翻耕(LT)分别比不翻耕处理(NT)减少径流28%和7%,40 m in时,浅翻耕(LT)和不翻耕(NT)处理径流量相当,深翻耕(DT)比这两个处理减少径流30%左右,土壤翻耕后在前期能提高土壤的入渗率,表现出经长年耕作后土壤退化的强烈特征,是“耕地越深,入渗越快”观念的根源;地表结皮是影响降雨入渗的主要因素,覆盖等保护性耕作更有利于土壤入渗。     

基于震源机制解反演应力场的一种改进方法

本文发展了基于震源机制解反演二维或三维背景应力场方位和主应力差比值R的一种可靠的、高精度的方法。所使用的震源机制解剔除了可能受到局部应力场的强烈影响、不能反映大尺度背景构造应力场信息的事件。去丛集后的数据利用k均值算法分为若干包含最少地震个数N_min到2N_min的组。人工实验测试表明,当R≈0.5时,N_min≈30才能保证不同应力体系包含不同噪声水平的情况下得到稳定的结果;当R接近于0或1时,则需要N_min≈45。另外的一个实验比较了两种从震源机制解中选择断层面方法的表现:(a)选择震源机制的滑动矢量和应力张量给出的剪应力矢量之间角度最小的那个节面;(b)给定应力场和摩擦系数,选择失稳系数最大的节面,它更接近最优断层。结果发现,失稳准则在所有试验的不同应力体系、主应力差比值、噪声水平的情况下得到的结果更准确。本文改进的方法将失稳准则迭代选择断层面和加入阻尼迭代反演各震源机制分组的应力场相结合。加入阻尼反演得到的各分区应力场结果中融合了相邻区域的应力场信息,能够得到不受分区影响的高精度结果。本文方法的...     

Estrogen equivalent concentration of individual isomer-specific 4-nonylphenol in Ariake sea water, Japan

Concentrations of 4-nonylphenol (NP) were determined by isomer-specific quantification of individual NP isomers based on relative response factor (RRF) quantification with GC–MS in combination with steam distillation extraction. Concentrations of NP in the Ariake Sea decreased with distance from the river mouth (St.A; 49 ng NP/l) to offshore areas (St.C; 11 ng NP/l). Even the least concentration in water from St.C in Ariake Sea was sufficient to have adverse effects on barnacles. The isomers, NP1–NP14 were separated by GC–PFC and identified structurally with NMR. The isomers varied in estrogenic activity with NP7 exhibiting the greatest estrogenic activity with a potency that was approximately 1.9 × 10⁻³ that of 17β-estradiol (E2) in recombinant yeast screen system. The coefficient of variation (CV) of NP isomer’s concentrations among three samples at St.A, B and C were 4–75%. This suggests that NP isomers might be independently degraded in aquatic environmental samples. The predicted estrogenic activity of measured concentrations of NP in Ariake Sea was 2.7–3.0-fold greater than the measured estrogen agonist activity.     

OHP地震台网

在海洋半球计划(OHP)实施的5年中，我们在西北太平洋区域改建了一个以POSEIDON项目启动的地震台网。我们在以下方面对该台网进行了改善：(1)用新设备替换原有设备；(2)改建地震计摆房；(3)建立一些新台站。我们也在西北太平洋区域进行了地震仪安装后的临时地震观测。我们在该台网内使用了宽频带OBS和陆地上的宽频带地震仪。本文将介绍我们在这段时间里的工作。     

Diamonds and Highly Reduced Minerals from Chromitite of the Ray-Iz Ophiolite of the Polar Urals: Deep Origin of Podiform Chromitites and Ophiolitic Diamonds

<正>The Uralide orogenic belt is a major early Paleozoic suture zone extending more than 3000 km in a N-S direction,and geographically divides Europe from Asia(Chemenda et al.,1997).Ophiolites,podiform chromitites and high pressure metamorphic rocks are well developed in the orogenic belt(Leech and Ernst,2000).The Ray-Iz     

推断勒夫波相速度的圆形台阵微震新技术

介绍了简单而又新颖的公式,使用微震的二分量,即圆形台阵记录的水平运动直接推断勒夫波相速度(cL)时,这些公式具有帮助作用。我们的公式与一般用于推断瑞雷波相速度(cR)的微震探测技术的空间自相关(SPAC)方法的公式类似。虽然SPAC方法现有的理论确实提供了估计cL的可能性,但这只能通过求解非线性的方程组才能实现,而其中待求解的未知数也包括cR以及瑞雷波?勒夫波的幂分配比。相反,在我们公式中cL是出现的唯一未知数。基于我们推荐公式——我们称为SPAC+L、SPAC-L和CCA-L(其中CCA表示无中心圆形台阵)法——的cL估算法的现场适用范围通过2个测试点的分析结果说明。在所提出的3种技术中,SPAC+L法由于表现最佳而出名。3种方法的有效波长范围下限是台阵半径r的2～5倍区域,上限是10～25r的区域。近年来,提出了类似的仅涉及cL的圆形台阵微震技术,但与它们相比,我们在此给出的方法,不是在数理计算上繁冗更少,就是在数学上更为简单。     

利用高频和低频GPS观测资料研究2018年MW7.9阿拉斯加科迪亚克地震的同震和震后形变

本文利用低频(15s)和高频(1s)全球定位系统(GPS)观测来研究2018年1月23号阿拉斯加科迪亚克岛M_W7.9地震的同震位移。动态(高频GPS观测值)和准动态(震后2小时的低频GPS观测值)同震位移与静态GPS同震位移三者之间相互一致,符合走滑型地震的形变特征。静态与准动态位移的比较结果表明该地震发生后4天内的震后形变可忽略不计。我们通过静态位移场反演了五段断层模型中的断层滑移,并且推测最大的滑移发生在右旋南—南东走向(2.27m)和左旋北东走向(2.42m)的两个子断层上。反演得到地震矩M₀为9.66×10²⁰N·m(M_W7.92)。在震后9个月时间内,12个附近GPS站点的水平形变均小于1cm,且最大震后形变值为7.4mm(AC26站点)。衰减时间为6.4天的对数模型比衰减时间为75.0天的指数模型能更好地拟合震后观测数据。观测到的震后形变可以通过余滑和/或黏弹性松弛模型来解释。     

A correlation between pulse diagnosis of human body and health monitoring of structures

The concept of health monitoring is a key aspect of the field of medicine that has been practiced for a long time. A commonly used diagnostic and health monitoring practice is pulse diagnosis, which can be traced back approximately five thousand years in the recorded history of China. With advances in the development of modem technology, the concept of health monitoring of a variety of engineering structures in several applications has begun to attract widespread attention. Of particular interest in this study is the health monitoring of civil structures. It seems natural, and even beneficial, that these two health-monitoring methods, one as applies to the human body and the other to civil structures, should be analyzed and compared. In this paper, the basic concepts and theories of the two monitoring methods are first discussed. Similarities are then summarized and commented upon. It is hoped that this correlation analysis may help provide structural engineers with some insights into the intrinsic concept of using pulse diagnosis in human health monitoring, which may be of some benefit in the development of modem structural health monitoring methods.     

Wintertime stratospheric anomalies— Part II: Sudden warmings

The process of stratospheric sudden warmings from development of planetary waves to the sudden cooling after reversal of mean zonal circulation will be studied with the primitive equations of heat and momentum balances. It will be explained that the sudden warmings may occur only in the polar regions of winter stratosphere where zonal mean temperature decreases poleward. The heating rate in the order of major warmings is produced by developed planetary waves in the stratospheric breaking layers. The particular perturbation structure characterized by large amplitude of wave 1 together with minimum of wave 2 discovered by Labitzke (1977) is crucial for initiation of major warmings. The cooling by the same mechanism can be produced in the regions with reversed mean temperature gradient.