Development of the Multipurpose Timing Instrument Based on BDS

With the increasingly high requirement of clock source accuracy for seismic data servers and equipment, the development of a multipurpose timing system is urgently needed in the seismic industry. We have developed low-cost timing equipment according to the actual earthquake industry situation. This set of timing equipment can provide a unified solution to the different environment and different earthquake instruments with different timing precision demands.     

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。     

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.     

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%.     

Review of Rapid Transformation of Floodplain Wetlands in Northeast China: Roles of Human Development and Global Environmental Change

Northeast China is the region with the largest area of wetlands in China. The Sanjiang Plain and the Songnen Plain are large freshwater marsh distribution regions that are affected by climate warming and by the increasing frequency and density of extreme weather and are the regions most subject to disturbances by human activities in Northeast China. The wetlands of the Sanjiang Plain and the Songnen Plain have shrunk severely in the past 60 years, and wetland functions have been reduced substantially because of climate change, unreasonable land use, fire episodes, engineering and construction works and urbanization. Large-scale agricultural development started in the 1950s has been the most important driving factor for wetland loss and degradation in the Sanjiang Plain. Water shortage has been the most important factor for degradation and fragmentation of wetlands in the Songnen Plain. To mitigate wetland degradation and better protect wetlands, special regulations, long-term mechanisms and technical support of wetland protection should be established. A wetland compensation program should be implemented, and technologies for increasing the adaptive capacity of wetlands should be developed. Moreover, it is most important to find the balanced threshold between agricultural development and wetland protection.     

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.     

条斑紫菜杂交重组品系(A-18)的筛选与特性分析

为筛选出藻体生长快且颜色与野生型色泽相近的条斑紫菜新品系,本研究从条斑紫菜绿色突变体和红色突变体种内杂交产生的后代中,分离出了优良品系A-18。日龄60 d时的叶状体平均长度、长宽比和单株湿质量,A-18品系分别为84.95 cm、49.46和0.52 g,分别是条斑紫菜野生型品系（WT）的3.12、7.01和1.36倍。日龄60 d时叶状体的叶绿素a和总藻胆蛋白含量,A-18品系分别为8.37和53.81 mg/g,均与WT品系较接近。日龄60 d时的叶状体平均厚度,A-18品系仅为20.22 μm,比WT品系降低了29%。另外,A-18品系的壳孢子放散总量为916.01万个/贝壳,是WT品系的1.55倍。综上所述,A-18品系具有生长快、长宽比值大、藻体薄、壳孢子放散量大等优良特性,且藻体颜色与野生型色泽相近,有望在生产中运用。