空间雷电探测实时采集定位系统

星载雷电探测定位系统是利用光学探测器探测闪电事件的地理位置和光脉冲波形,系统采用CPLD+DSP的数字图像处理方案,利用了CPLD复杂逻辑可编程特性将系统的部分或全部功能集成在一片CPLD上,减小了系统硬件复杂程度,节省了印制版空间.利用DSP高速数字信号处理特性完成实时处理图像数据的功能.系统用CPLD完成图像信号的采集、编码和存储控制,缩小了星载设备体积,简化了电路结构;用DSP完成大量图像数据处理工作,提高了系统工作的实时性.     

Deep Hierarchical Ensemble Model for Suicide Detection on Imbalanced Social Media Data

As a serious worldwide problem, suicide often causes huge and irreversible losses to families and society. Therefore, it is necessary to detect and help individuals with suicidal ideation in time. In recent years, the prosperous development of social media has provided new perspectives on suicide detection, but related research still faces some difficulties, such as data imbalance and expression implicitness. In this paper, we propose a Deep Hierarchical Ensemble model for Suicide Detection (DHE-SD) based on a hierarchical ensemble strategy, and construct a dataset based on Sina Weibo, which contains more than 550 thousand posts from 4521 users. To verify the effectiveness of the model, we also conduct experiments on a public Weibo dataset containing 7329 users’ posts. The proposed model achieves the best performance on both the constructed dataset and the public dataset. In addition, in order to make the model applicable to a wider population, we use the proposed sentence-level mask mechanism to delete user posts with strong suicidal ideation. Experiments show that the proposed model can still effectively identify social media users with suicidal ideation even when the performance of the baseline models decrease significantly.     

Automatic Search Dense Connection Module for Super-Resolution

The development of display technology has continuously increased the requirements for image resolution. However, the imaging systems of many cameras are limited by their physical conditions, and the image resolution is often restrictive. Recently, several models based on deep convolutional neural network (CNN) have gained significant performance for image super-resolution (SR), while extensive memory consumption and computation overhead hinder practical applications. For this purpose, we present a lightweight network that automatically searches dense connection (ASDCN) for image super-resolution (SR), which effectively reduces redundancy in dense connection and focuses on more valuable features. We employ neural architecture search (NAS) to model the searching of dense connections. Qualitative and quantitative experiments on five public datasets show that our derived model achieves superior performance over the state-of-the-art models.     

Catalytic asymmetric synthesis of enantioenriched α-deuterated pyrrolidine derivatives

The recent promising applications of deuterium-labeled pharmaceutical compounds have led to an urgent need for the efficient synthetic methodologies that site-specifically incorporate a deuterium atom into bioactive molecules. Nevertheless, precisely building a deuterium-containing stereogenic center, which meets the requirement for optimizing the absorption, distribution, metabolism, excretion and toxicity (ADMET) properties of chiral drug candidates, remains a significant challenge in organic synthesis. Herein, a catalytic asymmetric strategy combining H/D exchange (H/D-Ex) and azomethine ylide-involved 1,3-dipolar cycloaddition (1,3-DC) was developed for the construction of biologically important enantioenriched α-deuterated pyrrolidine derivatives in good yields with excellent stereoselectivities and uniformly high levels of deuterium incorporation. Directly converting glycine-derived aldimine esters into the deuterated counterparts with D₂O via Cu(i)-catalyzed H/D-Ex, and the subsequent thermodynamically/kinetically favored cleavage of the α-C–H bond rather than the α-C–D bond to generate the key N-metallated α-deuterated azomethine ylide species for the ensuing 1,3-DC are crucial to the success of α-deuterated chiral pyrrolidine synthesis. The current protocol exhibits remarkable features, such as readily available substrates, inexpensive and safe deuterium source, mild reaction conditions, and easy manipulation. Notably, the synthetic utility of a reversed 1,3-DC/[H/D-Ex] protocol has been demonstrated by catalytic asymmetric synthesis of deuterium-labelled MDM2 antagonist idasanutlin (RG7388) with high deuterium incorporation.

A strategy of combining H/D-Ex and azomethine ylide-involved 1,3-DC was developed for the construction of α-deuterated pyrrolidine derivatives in good yields with excellent stereoselectivities and uniformly high levels of deuterium incorporation.     

多检测GPC/SEC技术在高分子表征中的应用Ⅳ.氘化高分子的溶液性质

采用体积排斥色谱法／ 示差折光指数／ 直角激光光散射／ 示差粘度三检测联用技术表征了氘化聚苯乙烯、聚苯乙烯和氘化聚苯乙烯－ 聚异戊二烯。结果表明,在θ条件下,虽然氘化聚苯乙烯的化学依赖性常数υＴ,ＤＰＳ比聚苯乙烯的化学依赖性常数υＴ,ＰＳ大,但２５ ℃时在四氢呋喃中,氘化聚苯乙烯的分子尺寸仍小于聚苯乙烯的分子尺寸。由于嵌段共聚物的淋洗体积随组成变化,所以用传统的ＳＥＣ／ＲＩ得不到准确的分子量。经比较膜渗透、小角激光光散射和基质辅助激光脱吸与离子化时间飞行质谱等的实验结果,证明体积排斥色谱法／ 示差折光指数／ 直角激光光散射／ 示差粘度三检测技术能准确地得到氘化二嵌段共聚物的分子量以及其它重要信息。     

白酒中游离有机酸的定量测定

本文介绍了一种简单、准确测定白酒中游离有机酸的方法。酒样经中和、浓缩后,未经衍生直接注入毛细管色谱柱,经气相色谱-质谱鉴定并采用三种内标物定量,可准确测定白酒中C2～C18的二十种游离脂肪酸及三种苯羧酸,结果重现性良好。     

Trace determination of hexabromocyclododecane diastereomers in water samples with temperature controlled ionic liquid dispersive liquid phase microextraction

A novel temperature controlled ionic liquid dispersive liquid phase microextraction(TCIL-DLPME) coupled with rapid resolution liquid chromatography-electrospray tandem mass spectrometry(RRLC-ESI-MS-MS) has been developed for the enrichment and determination of three hexabromocyclododecane diastereomers(HBCDs) in water samples.Green solvent ionic liquid(IL) was used as extraction solvent instead of toxic organic solvents.This technique also avoided the usage of dispersive solvent.Some important parameters that might affect the extraction efficiency were optimized.Under the optimum conditions,good linear relationship,sensitivity and reproducibility were obtained.All the limits of detection for the three diastereomers were 0.1 ng/ mL.The linear range was obtained in the range of 1-100 ng/mL for the total amount of three HBCD diastereomers.It was satisfactory to analyze real environmental water samples with the recoveries ranging from 77.2%to 99.3%.The main advantage of the method is toxic organic solvent-free.     

Thermoresponsive hybrid hydrogel of oxidized nanocellulose using a polypeptide crosslinker

Thermoresponsive hybrid nanocellulose hydrogels were prepared from a mixture of oxidized nanocellulose and elastin-like polypeptide (ELP). Positively charged ELP was used as a polymeric crosslinker for conjugation with negatively charged nanocellulose. Hydrogel formation was triggered by a simple increase in temperature, and the hydrogel was reversibly returned to the liquid phase by decreasing temperature. Surface potential measurement confirmed the electrostatic properties of oxidized nanocellulose and ELP molecules. The surface morphology of hydrogels was observed by atomic force microscopy and field emission-scanning electron microscopy. Conformational changes in the ELP/nanocellulose hybrid were characterized by circular dichroism. The ELP/nanocellulose hybrid hydrogel was noncytotoxic and suitable for encapsulating cells, indicating its potential for biomedical applications.     

促红细胞生成素B螺旋表面肽的代谢稳定性结构修饰：设计、合成及其提高的肾保护作用

肾脏缺血缺氧以及再灌注过程都将导致肾小管上皮细胞凋亡,使肾功能严重受损.肾脏的缺血再灌注损伤是移植肾功能延迟恢复的主要原因并能诱导急慢性排斥,影响肾存活率.近年来发现,衍生于促红细胞生成素（EPO）的B螺旋亚基亲水表面序列的肽链（HBSP）,对肾脏缺血再灌注损伤具有显著的保护作用,但其在体内极短的半衰期（约2min）极大地限制了它的临床应用.因此,本研究采用构象约束、全D-构型氨基酸替换和N-端封闭策略,设计了3种类型的EPOB螺旋表面肽衍生物,旨在提高其代谢稳定性环肽的设计采用了对氧化还原稳定的硫醚键和相对刚性的亚砜键两种环合方式.在多肽的合成上,采用微波辅助多肽自动合成和手工合成两种模式有机结合;优化了硫醚环合工艺,应用微波加热进行硫醚环肽的合成,大大提高了产率和效率;利用圆二色（CD）谱确定了亚砜环肽的相对构型.活性实验表明,相对于线性母肽HBSP,本文设计合成的代谢稳定衍生肽对大/小鼠肾脏缺血再灌注损伤均有显著提高的保护作用,且硫醚和R-构型亚砜环肽的肾脏保护活性强于S-构型亚砜环肽.而且,环化确实提高了功能肽的血浆稳定性.因此,本文合成的硫醚环肽一周一次注射剂量等效于线性肽HBSP一日三次剂量对小鼠肾损伤的保护作用.     

三硝基苯-对位取代苯酚负离子荷移复合物从头算研究

运用G94W量子化学程序,在HF/3-21G基组水平上对三硝基苯-对位取代苯酚(取代基:CH~3O-,CH~3-,Cl-)负离子的电荷转移复合物进行从头计算。把电荷转移复合物看成一个超分子,研究该系列复合物的稳定性、电荷转移及几何构型等规律。计算结果表明,苯酚负离子供电中心O沿一倾角指向三硝基苯中的任意相邻两个硝基之间的C位置上,复合物的稳定性按对位取代苯酚取代基CH~3O-,CH~3-,Cl-的次序减小,与实验规律相一致。计算结果还表明,形成该系列复合物具有明显的电荷转移,其稳定性与电荷转移量有关等。