ON THE FUTURE PROSPECTS OF METEOR DETECTIONS (INVITED REVIEW)

The successful application of modern observing techniques for Leonid storm observations show that meteor (shower) detections will have a bright future if the field will pursue difficult but important questions. How to forecast a satellite threatening meteor storm? What happens to the organic matter in meteors and can this be an important source of prebiotic molecules? What range of variations in composition and morphology exists among cometary grains and what does this tell us about the origin of the solar system? What long-period comets approach Earth orbit and can meteoroid streams provide early warning for giant impacts? What are the sources of interstellar and interplanetary grains? Just to mention a few. To answer these questions will need new technologies and facilities, some of which are being developed for other use. This may include NASA’s Stratospheric Observatory For Infrared and sub-millimeter Astronomy (SOFIA). In addition, big-science space missions can drive the field if meteor detections are an integral part. Special events, such as meteor outbursts and the “artificial meteor” from the reentry of sample return capsules from interplanetary space, can mobilize observing and theoretical efforts. These and other future opportunities are briefly discussed.     

MRI脊髓探测定位新方法

本文介绍了ＭＲＩ在脊髓成像中，脊椎体附件都是低信号，给病变定位带来不便，为了解决这一问题，根据脊髓圆锥在脊柱里的特定位置及使用自制脂肪囊固定在脊柱体表解剖部标志上，用于脊髓病变定位诊断。     

一种海洋柔性胶囊波能发电装置研究

海洋波浪能可再生能源的开发是未来发展的趋势,开发设计更为高效的波能转换利用装置是开发利用波浪能的关键。根据脉搏脉动机理,设计发明了一种柔性胶囊发电装置,利用柔性结构的强收缩性,让其随着波峰波谷收缩扩张,进而形成脉动来传输水体,使相连尾端竖管内水位随着脉动骤升骤降来压缩排出和快速吸入空气。进行了一系列探索性实验,着重研究柔性材料厚度、波高、周期、气室孔径对该试验装置的波能转换率的影响,数据表明,柔性硅胶管有很好的聚波作用,气室的设计和建造对波能转换效率有较大的影响。     

黑龙江林口MB6.4深震前通河地磁谐波振幅比异常特征

采用黑龙江通河地磁台分钟值数据进行谐波振幅比计算,结果显示：2016-01-02黑龙江林口MB6.4深源地震前,距离震中150 km的通河地磁台谐波振幅比出现明显异常,异常特征有：1）地磁谐波振幅比YZHx和YZHy主要表现为“下降-转折-恢复”的形态;2）谐波振幅比异常变化中的转折上升形态具有由深（较长周期）至浅（较短周期）的迁移特征;3）2014-03~2016-01YZHy在不同深度出现介质电性不同步异常;4）YZHy异常幅度大于YZHx异常幅度。异常产生的原因可能是由于西太平洋板块持续以高速度、小倾角向欧亚大陆下方俯冲,林口地震前孕震体应力变化导致地磁台站附近局部介质电性产生变化。     

方斑东风螺不同批次罗同质量的比较

2005年5月～8月在雷州市覃斗镇海威水产种苗基地的室内水池进行方斑东风螺亲螺培育．对亲螺不同批次产出的卵囊、卵、及其幼虫进行比较。结果表明：随着亲螺产卵批次的增加，亲螺产卵囊数、卵囊含卵数、产卵量逐次减少；卵囊长、宽逐次变小．厚逐次增加，形状由葵花子片状的比例大变为棒状的比例大；幼虫浮游期逐次延长；变态期幼虫壳长逐次变小；各批次之间的变态率逐次降低；卵径、孵化率、出囊幼虫大小差异不显著。     

高分辨率遥感影像建筑物提取的注意力胶囊网络算法

高分辨率遥感影像建筑物自动提取在防灾减灾、灾害估损、城市规划和地形图制作等方面具有重要意义。但是,目前常用的传统卷积神经网络模型存在异变性强而同变性弱缺陷。针对该问题,本文提出一种基于通道和空间双注意力胶囊编码—解码网络DA-CapsNet (dual-attention capsule encoder-decoder network)的建筑物提取通用模型。该模型通过胶囊卷积和空间—通道双注意力模块增强高分辨率遥感影像中建筑物高阶特征表达能力,实现建筑物遮挡部分以及对非建筑不透水层的准确提取与区分。模型首先利用胶囊编码—解码结构提取并融合多尺度建筑物胶囊特征,获得高质量建筑物特征表达。之后,设计通道和空间注意力特征模块进一步增强建筑物上下文语义信息,提高模型性能。本文选取3种高分辨率建筑物数据集进行试验,最终的平均精度、召回率和F1-score分别为92.15%、92.07%和92.18%。结果表明,本文提出的DA-CapsNet能有效克服高分辨率遥感影像中的空间异质性、同物异谱、异物同谱以及阴影遮挡等影响,实现复杂环境下的高精度建筑物自动提取。     

MARCO POLO: near earth object sample return mission

MARCO POLO is a joint European–Japanese sample return mission to a Near-Earth Object. This Euro-Asian mission will go to a primitive Near-Earth Object (NEO), which we anticipate will contain primitive materials without any known meteorite analogue, scientifically characterize it at multiple scales, and bring samples back to Earth for detailed scientific investigation. Small bodies, as primitive leftover building blocks of the Solar System formation process, offer important clues to the chemical mixture from which the planets formed some 4.6 billion years ago. Current exobiological scenarios for the origin of Life invoke an exogenous delivery of organic matter to the early Earth: it has been proposed that primitive bodies could have brought these complex organic molecules capable of triggering the pre-biotic synthesis of biochemical compounds. Moreover, collisions of NEOs with the Earth pose a finite hazard to life. For all these reasons, the exploration of such objects is particularly interesting and urgent. The scientific objectives of MARCO POLO will therefore contribute to a better understanding of the origin and evolution of the Solar System, the Earth, and possibly Life itself. Moreover, MARCO POLO provides important information on the volatile-rich (e.g. water) nature of primitive NEOs, which may be particularly important for future space resource utilization as well as providing critical information for the security of Earth. MARCO POLO is a proposal offering several options, leading to great flexibility in the actual implementation. The baseline mission scenario is based on a launch with a Soyuz-type launcher and consists of a Mother Spacecraft (MSC) carrying a possible Lander named SIFNOS, small hoppers, sampling devices, a re-entry capsule and scientific payloads. The MSC leaves Earth orbit, cruises toward the target with ion engines, rendezvous with the target, conducts a global characterization of the target to select a sampling site, and delivers small hoppers (MINERVA type, JAXA) and SIFNOS. The latter, if added, will perform a soft landing, anchor to the target surface, and make various in situ measurements of surface/subsurface materials near the sampling site. Two surface samples will be collected by the MSC using “touch and go” manoeuvres. Two complementary sample collection devices will be used in this phase: one developed by ESA and another provided by JAXA, mounted on a retractable extension arm. After the completion of the sampling and ascent of the MSC, the arm will be retracted to transfer the sample containers into the MSC. The MSC will then make its journey back to Earth and release the re-entry capsule into the Earth’s atmosphere.     

Vertebrate remains from the Cenomanian (Late Cretaceous) plant-bearing Lagerstätte of Puy-Puy (Charente-Maritime,France)

The vertebrate remains from the early Cenomanian Lagerstätte of Puy-Puy (Tonnay-Charente, Charente-Maritime, France) are described. They consist of two hybodont shark egg capsules (Palaeoxyris sp.) and a single isolated body contour feather. The hybodont shark Tribodus is regarded as the most likely producer of the egg capsules, while the feather belonged to an indeterminate (avian or non-avian) theropod. These rare specimens are the first vertebrate fossils recovered from the plant-bearing clay of Puy-Puy and add to the short faunal list of the locality, thus providing important information for the palaeoecological reconstruction of this mid-Cretaceous paralic Lagerstätte. The fossils described here represent the first Cenomanian occurrence of Palaeoxyris and one of the very few records of Cenomanian feathers.     

活塞圆筒和多面砧高压装置中常用的氧逸度控制和原位监测方法

氧逸度是定量表示一个体系氧化还原能力的指标，反映了体系中氧气的分压或者逃逸能力。在地球科学中，它反映了岩石和矿物中变价元素的氧化还原状态，指示了不同岩石矿物氧化性/还原性的相对强弱。相同岩石矿物不同氧逸度可以导致其物理化学性质发生大的改变，因此在实验地球科学中准确控制并监测高温高压实验条件下的氧逸度具有非常重要的意义。本文从实验技术角度出发，首先介绍了活塞圆筒和多面砧高压装置中利用双胶囊技术在不含水和含水体系中控制氧逸度的方法、原理、装置和注意事项；接着描述了用过渡金属合金固溶体和惰性金属合金作为氧传感器原位测量氧逸度的原理、注意事项和地质应用，然后展示了氧离子固体电解质法控制和监测氧逸度的原理、装置和局限，提出了可能的改进方法。目前由于技术限制，氧逸度在高压实验中的控制和监测方法还不成熟，导致其对矿物和岩石物理化学性质的影响极可能被低估甚至错估。因此积极研究发展并推动高压下氧逸度的控制和监测技术非常重要且必要。     

A protocol for preparing subfossil chironomid head capsules (Diptera: Chironomidae) for stable isotope analysis in paleoclimate reconstruction and considerations of contamination sources

Several techniques are available to examine the isotopic composition of historic lake waters, providing data that can subsequently be used to examine environmental changes. A recently-developed technique is the stable oxygen isotope analysis of subfossil chironomid (Diptera: Chironomidae) head capsules (mostly chitin) preserved in lake sediments. This technique involves a high Temperature Conversion Elemental Analyzer (TC/EA), which has been a relatively recent addition to the suite of online peripherals for analyzing the stable isotopic composition of organic samples. The highly precise and accurate ¹⁸O/¹⁶O and D/H measurements obtainable using the TC/EA with samples in the microgram range make this instrumentation suitable for studying geochemical and biological processes. Preparation of organic samples for isotopic analysis typically requires first weighing each sample into silver/tin capsules. These capsules can introduce oxygen and hydrogen contamination (a “blank effect”), which is especially problematic for analysis of small organic samples (e.g. less than 100 μg). Here we tested tin and silver capsules from two manufacturers and a range of sizes to assess contamination to small organic samples on the TC/EA. We also assessed how a method for cleaning silver capsules affected our analysis of commercial chitin. In general, capsules made of silver have less detectible oxygen than those made of tin, and capsules from the two manufacturers varied in their detectible oxygen. There was no detectable H contamination from silver capsules. In addition to our empirical findings, we present a model demonstrating the influence that contaminant oxygen can have on the δ¹⁸O of small organic samples. Sample mass becomes an important issue for such analyses. In light of our findings, we recommend a minimum sample mass ≥50 μg (approximately 120 whole chironomid head capsules) on a TC/EA-IRMS (Delta^plus XP system). Finally, we present a detailed protocol for preparing and transferring chironomid head capsules into silver capsules that minimizes the influence of contaminant oxygen. This protocol provides the paleo-community with another potential method for reconstructing paleoenvironments.