Recent studies have shown that the surfactants bearing an ultra‐long hydrophobic chain (>C18) exhibit unique self‐assembly properties. However, their synthesis and surface activities have been less documented. In this work, monounsaturated alkyl dimethyl amidopropyl betaines, UCnDAB (n = 18, 22, and 24), were prepared by the reaction of the corresponding fatty acids with N,N‐dimethyl‐1,3‐propanediamine, followed by quaternization with sodium choloroacetate of the obtained intermediates. The intermediates and final surfactants were characterized by 1H NMR and ESI‐HRMS, respectively. Krafft temperature (TK) and surface activities of the surfactants were also examined. It was found that TK of all these surfactants is lower than 0 °C, and their critical micellar concentration (CMC) is within the range of 10−3 mmol/L. In addition, the linear relationship between lg CMC and n is still in evidence.

Dam monitoring usually involves environmental variables (e.g., the water level and temperature) and effect variables (deformation, cracking, seepage, etc.).The associated monitoring data can reflect the trends in these variables over time and are important information for managers to understand the operational status of a dam. Therefore, research on monitoring data analysis methods is very important for monitoring dam safety. Dam monitoring data analysis methods can be divided into monitoring model, monitoring index, and abnormal value detection methods. A monitoring model takes environment variables as independent variables and effect variables as dependent variables. By studying the interactions among variables, the trends of effect variables can be learned for monitoring and prediction. A monitoring index is established to denote warning or extreme value considering the previous changes in effect variables to determine whether future changes are safe.Abnormal value detection is also an important method of finding abnormal changes in the dam state. This paper summarizes the principles, research progress, deficiencies, and development trends of these three types of monitoring data analysis methods. This review promotes research in the field of dam safety monitoring.

Biomarkers of paleolake deposits from Qarhan Salt Lake in Qaidam Basin, northwest China were systematically analyzed and the A-C series compounds of branched aliphatic alkanes with quaternary substituted carbon atom (BAQCs) were identified. The homologous distinguished three series, A-C, were identified as 5,5-diethylalkanes, 6,6-diethylalkanes and 5-butyl, 5-ethylalkanes series, and their relative abundance was A > B > C. Series A and C were characterized by odd carbon numbers, whereas series B was characterized by even carbon numbers. The high values of series A corresponded with the high values of series B and C. Therefore, it can be concluded that series A, B and C possess a similar biological origin. The abundance of series A was relatively low in the lower part of the section compared with that in the upper part, implying that these series originated from bacteria and/or algae more prevalent in fresh-mesohaline water, and such kinds of bacteria and/or algae are most likely to be thermophilous species. The A25/nC 25 ratio differences in the section show that such branched aliphatic alkanes can be treated as one kind of environmental change proxy for paleolake evolution and may provide important information for the climate reconstruction of the Late Pleistocene.Qaidam Basin, shell bar section, branched aliphatic alkanes, paleoenvironment

Image guided depth completion is the task of generating a dense depth map from a sparse depth map and a high quality image. In this task, how to fuse the color and depth modalities plays an important role in achieving good performance. This paper proposes a two-branch backbone that consists of a color-dominant branch and a depth-dominant branch to exploit and fuse two modalities thoroughly. More specifically, one branch inputs a color image and a sparse depth map to predict a dense depth map. The other branch takes as inputs the sparse depth map and the previously predicted depth map, and outputs a dense depth map as well. The depth maps predicted from two branches are complimentary to each other and therefore they are adaptively fused. In addition, we also propose a simple geometric convolutional layer to encode 3D geometric cues. The geometric encoded backbone conducts the fusion of different modalities at multiple stages, leading to good depth completion results. We further implement a dilated and accelerated CSPN++ to refine the fused depth map efficiently. The proposed full model ranks 1st in the KITTI depth completion online leaderboard at the time of submission. It also infers much faster than most of the top ranked methods. The code of this work is available at https://github.com/JUGGHM/PENet_ICRA2021.

Surface-assisted laser desorption/ionization (SALDI) mass spectrometry (MS) has become an attractive complementary approach to matrix-assisted laser desorption/ionization (MALDI) MS. SALDI MS has great potential for the detection of small molecules because of the absence of applied matrix. In this work, a functionalized porous TiO2 film immobilized with gold nanoparticles (AuNPs-FPTDF) was prepared to enhance SALDI MS performance. The porous TiO2 films were prepared by the facile sol–gel method and chemically functionalized for dense loading of AuNPs. The prepared AuNPs-FPTDF showed superior performance in the detection and imaging of small molecules in dual-polarity modes, with high detection sensitivity in the low pmol range, good repeatability, and low background noise compared to common organic MALDI matrixes. Its usage efficiently enhanced SALDI MS detection of various small molecules, such as amino acids and neurotransmitters, fatty acids, saccharides, alkaloids, and flavonoids, as compared with α-cyano-4-hydroxycinnamic acid, 9-aminoacridine, and the three precursor substrates of AuNPs-FPTDF. In addition, the blood glucose level in rats was successfully determined from a linearity concentration range of 0.5–9 mM, as well as other biomarkers in rat serum with SALDI MS. More importantly, the spatial distribution of metabolites from the intact flowers of the medicinal plant Catharanthus roseus was explored by using the AuNPs-FPTDF as an imprint SALDI MS substrate in dual-polarity modes. These results demonstrate wide applications and superior performances of the AuNPs-FPTDF as a multifunctional SALDI surface with enhanced detection sensitivity and imaging capabilities.

The Kepler-9 system harbors three known transiting planets. The system holds significant interest for several reasons. First, the outer two planets exhibit a period ratio that is close to a 2:1 orbital commensurability, with attendant dynamical consequences. Second, both planets lie in the planetary mass "desert" that is generally associated with the rapid gas agglomeration phase of the core accretion process. Third, there exist attractive prospects for accurately measuring both the sky-projected stellar spin-orbit angles as well as the mutual orbital inclination between the planets in the system. Following the original Kepler detection announcement in 2010, the initially reported orbital ephemerides for Kepler-9 b and c have degraded significantly, due to the limited time base-line of observations on which the discovery of the system rested. Here, we report new ground-based photometric observations and extensive dynamical modeling of the system. These efforts allow us to photometrically recover the transit of Kepler-9 b, and thereby greatly improve the predictions for upcoming transit midtimes. Accurate ephemerides of this system are important in order to confidently schedule follow-up observations of this system, for both in-transit Doppler measurements as well as for atmospheric transmission spectra taken during transit.

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