采用GPS观测值进行三维形变分析的构想

在已知地表度量张量的基础上,给出了根据测站的GPS复测值计算地表形变张量、主方向、线应变、面应变、高斯曲率与平均曲率的有关公式,并着重对地表的内蕴与外蕴形变概念作了阐述,最后指出利用地表内蕴与外蕴形变量能较好地描述地表的三维形变。     

荒漠草原区风力发电场建设前后的植被变化

调查了甘肃景泰荒漠草原区一处风电场基础设施建设和运行对植被的影响。结果表明:荒漠草原区百兆瓦级风力发电场建设造成直接植被生产力损失量为6.79 g·m^-2·a^-1,间接植被生产力损失量为91.43 g·m^-2·a^-1。随着扰动程度增加,物种丰富度降低,均匀度减小。在工程运行后,经历近10 a的自然恢复,核心扰动区虽然物种单一,但植被生产力是次级扰动区的两倍以上,为间接扰动区和未扰动区的50%和33%左右;而间接扰动区植被生产力仅为未扰动区的50%。总体上,风电工程扰动对区域植被的影响,不仅在于建设期对局地群落植被生产力的完全丧失,更重要的是在运行期间对周边大面积间接影响区群落植被生产力的大幅度降低,而且这种影响是长期和持续性的。     

迁居意愿、地方依赖和社区认同——北京中关村地区居住选择调查分析

迁居行为及其意愿反映了城市居民对美好生活的向往,揭示了城市居住环境是否能够满足居民的需要。论文从迁居意愿的视角,将地方依赖和社区认同引入迁居研究中,并采用问卷调查和访谈相结合的方法来分析城市居民的居住选择。运用Williams量表,在292份调查问卷和52份深度访谈的基础上,对北京中关村地区展开了调查研究。结果表明：中关村周边社区居民对就业和子女教育具有明显的地方依赖和较高的社区认同感。在292名被调查者中,共有115名居民有迁居意愿,占被调查者总数的39.4%。其中,在就业和子女教育地方依赖程度较低的调查人群中,这一比例分别上升至47.2%和54.2%。此外,有迁居意愿的居民大多社区认同感不高,在115名有迁居意愿的居民中,仅有4人对所在社区具有强烈认同感。论文从地方感的角度丰富了居住空间的研究内容,为理解当代城市居住空间的特点、提升城市空间建设质量提供了参考依据。     

The response of spiders to less-focused non-crop habitats in the agricultural landscape along the lower reach of the Yellow River

Journal of Geographical Sciences - Non-crop habitats have been suggested to impact local biodiversity significantly in agricultural landscapes. However, there have been few studies of the effects...     

黑潮延伸体区域脱落涡旋的时空特征分析

本文利用1993-2015年AVISO卫星高度计融合数据,统计分析了从黑潮延伸体流轴脱落涡旋的空间分布特征、运动属性以及季节、年际和类年代际变化。研究结果表明,23年间共追踪到242个气旋涡,276个反气旋涡,脱落的涡旋主要分布在沙茨基海隆以西区域。从脱落涡旋的源地空间分布来看,气旋涡的形成区域有两个高值区,一个位于黑潮延伸体流轴稳定弯曲处,即144°~146°E之间的上游区域;另一个位于沙茨基海隆西侧156°E处。而反气旋涡的形成区域也有两个高值区,一个位于沙茨基海隆以西的下游区域,另一个位于148°E处。这些在上游和下游脱落的涡旋大多向西移动,其中有88%的涡旋再次被流轴吸收。脱落涡旋的数量显示出了明显的年际和类年代际变化。在流轴的上下游区域,类年代际和年际变化分别占主导地位。并且在上游区域,脱落涡旋的类年代际变化与黑潮延伸体的强度呈负相关。在季节变化上,夏季脱落形成的涡旋最多,冬季最少。     

大叶藻微粒体GST基因对温度胁迫响应的分子机制

为了分析鳗草（Zostera marina）中微粒体谷胱甘肽S-转移酶在不同温度下的基因表达规律以及响应机制,本文通过在大肠杆菌中表达ZmGST,纯化重组蛋白以及热稳定性分析,以此为进一步阐述Z. marina的种群退化机制并提供理论依据。总之,鳗草中的微粒体GST的热稳定性和其对温度变化的响应决定了其对温度的耐受范围,并进而影响其恢复力。     

An Analytical Solution for Nearshore Circulation Driven by Focused/Defocused Waves

An offshore shoal or bar refracts ocean surface waves and causes wave focusing/defocusing on the adjacent beach.Wave focal patterns characterized by alongshore variations in wave height, wave angle, and breaking location induce alongshore non-uniformities of wave setup and nearshore circulation, e.g., rip currents and alongshore currents, in the surfzone. A simplified analytic model for nearshore circulation generated by focused/defocused waves on a planar beach is developed and theoretical solutions are obtained using transport stream function and perturbations in alongshore distributions of wave height and wave angle at the breaker line. The analytic model suggests that alongshore currents are strongly affected by a pair of counter-rotating vortices generated shoreward of the wave focal zone. The vortices are persistent, and their strengths depend on the amplitudes of alongshore variations in wave height and wave angle. The alongshore gradient in wave height tends to intensify the vortices while the convergence of wave angle tends to weaken the vortices. Divergent flows associated with the vortices in the surfzone are intense,strengthening alongshore currents in the downstream of the wave focal zone and weakening alongshore currents or causing flows reversal in the upstream. Alongshore currents are modulated by rip currents associated with the wave focusing/defocusing patterns.     

丽江2.4米望远镜的圆顶侧窗自动化控制系统

丽江2.4 m望远镜的圆顶采用方位随动和滑动式天窗的超半球结构,起初为改善因圆顶和望远镜终端电子设备引起的内外大气湍流,设计了大面积的多组机械式侧窗。但由于高平台手动操作危险、缓慢、不精确且易损坏,为实现侧窗稳定的多组自动控制,开发了基于STM32板的嵌入式圆顶侧窗自动控制系统,利用WiFi模块、串口模块和手柄实现侧窗的远程和多通道控制。同时结合气象数据、圆顶位置信息等使系统能根据气象阈值进行预警、自动开合,并尽量减小风对望远镜振动的影响。侧窗控制系统的设计可满足上层系统集成的需要。该系统稳定可靠,能满足侧窗的自主运行与人为控制。     

Calibration of the DAMPE Plastic Scintillator Detector and its on-orbit performance

The DArk Matter Particle Explorer(DAMPE) is a space-borne apparatus for detecting the highenergy cosmic-ray-like electrons, γ-rays, protons and heavy ions. The Plastic Scintillator Detector(PSD)is the top-most sub-detector of the DAMPE. The PSD is designed to measure the charge of incident highenergy particles and it also serves as a veto detector for discriminating γ-rays from charged particles. In this paper, a PSD on-orbit calibration procedure is described, which includes the five steps of pedestal, dynode correlation, response to minimum-ionizing particles, light attenuation function and energy reconstruction.A method for reconstructing the charge of incident high energy cosmic-ray particles is introduced. The detection efficiency of each PSD strip is verified to be above 99.5%; the total efficiency of the PSD for charged particles is above 99.99%.     

Variation of physical properties across the green valley for local galaxies

We selected a sample of nearby galaxies from the Sloan Digital Sky Survey Data Release 7(SDSS DR7) to investigate the variation of physical properties from the blue cloud to green valley to red sequence.The sample is limited to a narrow range in the color-stellar mass diagram. After splitting green valley galaxies into two parts—a bluer green valley(green 1) and a redder one(green 2) and three stellar mass bins,we investigate the variation of physical properties across the green valley region. Our main results are as follows:(i) The percentages of pure bulge and bulge-dominated/elliptical galaxies increase gradually from blue cloud to red sequence while the percentages of pure disk and disk-dominated/spiral galaxies decrease gradually in all stellar mass bins and different environments.(ii) With the analysis of morphological and structural parameters(e.g., concentration(C) and the stellar mass surface density within the central 1 kpc(Σ1)), red galaxies show more luminous and compact cores than both green valley and blue galaxies, while blue galaxies show the opposite behavior in all stellar mass bins.(iii) A strong negative(positive) relationship between bulge-to-total light ratio(B/T) and specific star formation rate(sSFR)(D_(4000)) is found from blue to red galaxies. Our results indicate that the growth in bulge plays an important role when the galaxies change from the blue cloud, to the green valley and to the red sequence.