2,6-二甲氧基-2-嘧啶氧基-N-芳基苄胺衍生物的酸催化Smiles重排反应动力学

研究了酸催化下的2,6-二甲氧基-2-嘧啶氧基-N-芳基苄胺衍生物Smiles重排反应的动力学,考察了盐酸的初始浓度、溶剂、反应温度和取代基对反应速率的影响。结果表明,盐酸的初始浓度增加,重排反应速率加快;在单一溶剂中反应速率的顺序为:甲醇>乙醇>二甲基亚砜>乙腈,而在甲醇/水(1:1,V/V)的混合溶剂中反应速率明显增加,其表观反应速率常数(k_(obs))值是甲醇溶剂中的5.27倍;在25-45℃温度范围内,各衍生物的反应速率随着温度的升高而加快,其活化能(73.99-76.92 kJ·mol^(-1))、活化焓(71.57-74.38 kJ·mol^(-1))及Gibbs自由能(81.51-85.77 kJ·mol^(-1))数值相近,仅活化熵(-24.38--47.11 J·K^(-1)·mol^(-1))有一定的差别;取代基常数和表观速率常数之间呈现一定的线性关系,环上吸电子基团的存在有利于反应速率的提高;实验验证了反应机理的合理性。

O-N型竞争smiles重排反应研究

本研究是O-N型竞争smiles重排反应的首次发现和报道。通过对多种底物和多种条件的筛选,发现以2-甲基-5,7-二氟-8-羟基喹啉为底物,在Cs2CO3\Na H\NMP\DMPU\125℃条件下,反应按照竞争smiles重排反应路径进行,产率可达到83%。本论文的研究将给芳香环并恶嗪类药物中间体和精细化学品的合成,以及芳香酚类化合物到芳香胺类化合物的转化提供实验依据和理论指导。

SMILES表达式的子结构关系检测算法

为理解SMILES表达式中包含的结构信息,判断化合物之间的结构关系,提出一种检测SMILES表达式之间子结构关系的算法。依据常见原子、化学键和原子间的支链关系,将SMILES表达式切割成一个个不可再分的片段,通过比较切片种类、切片对应的数量判断表达式之间是否具有子结构匹配关系。实验结果表明,该算法简单、准确性高,可为化合物检索及MOL文件分类作参考。

SMILES扩展算法及其在族性结构处理中的应用

目前在所建立的族性结构检索系统中一般包括两个步骤，即族性结构的拆分和还原图（Reduced Graph）的生成。本文在分析SMILES线性编码算法的基础上，通过扩展其算法快速简单地实现了上述两个过程，将SMILES线性编码的使用范围扩展到族性结构研究领域，结合具体实例说明了SMILES线性编码在处理族性结构信息中的应用。

Q&Q SmileSolar科技感潮流腕表

Q＆Q（Quest＆Quality）是创建于1976年的日本潮流腕表品牌,于近期推出了绿色光能腕表——Q＆Q Smile Solar系列。基于高品质手表机芯,Q＆Q Smile Solar在2点~11点刻度间,独创出微笑曲线造型的光能感应带,极富科技感,并融入年轻时尚的流行色彩和极简主义元素设计,在保持日系一贯的高品质态度基础上打造时尚个性。环保主义的产品宗旨,与亲民的价格,让这款手表在日本年轻潮系族群中火速风靡。

一种用SMILES码构建虚拟组合化学库的新方法

提出了一种利用SMILES码构建虚拟组合化学库的新方法。该方法用SMILES码代表骨架和侧链,通过对其进行排列组合生成虚拟组合化学库。用户可设定ADME筛选条件对生成的库进行初筛,以舍弃在理论上药代动力学行为不好的分子。该法通过构建一个抗2型糖尿病药物虚拟组合化学库(A2DDVCL)而得到了验证。A2DDVCL建立在过氧化物酶增殖体活化受体(PPAR)配体的基础上,拟从其中发现治疗慢性代谢疾病特别是2型糖尿病的药物。

基于SMARTS和SMILES编码的化学结构分类方法

中药化学结构分类在化学类数据库检索、药物设计及数据挖掘分析过程中都发挥重要作用。目的:对数据库中收集的化学结构信息进行分类标引,以提高检索效率便于数据管理与知识挖掘。方法:采用可用于互联网和在线服务的SMARTS、SMILES文本编码技术的中药化学结构分类方法。结果:实现了对《中华本草》的1万多的化学结构进行自动分类。结论:基于SMARTS、SMILES文本编码技术的化学结构分类方法可行且简便易学。

2-嘧啶氧基-N-芳基苄胺类衍生物的酸催化Smiles重排反应条件的快速筛选和产物的高效制备

在室温、甲醇水溶剂条件下,以盐酸为酸催化剂,以2-嘧啶氧基-N-芳基苄胺衍生物为反应原料,基于高效液相色谱(HPLC)监测,能快速、高效、便捷地实现Smiles重排反应.本方法的优点在于反应体系溶剂可重复利用,在无需分离的条件下即可取得良好的产率和纯度.从催化剂和溶剂的廉价以及反应的高效简便和绿色温和角度考虑,该合成方法具有较好的实用性和绿色经济性.

SMILE治疗近视患者效果及对角膜生物力学的影响

目的:探讨飞秒激光小切口角膜基质透镜取出术(SMILE)治疗近视患者的效果及对角膜生物力学的影响。方法:回顾性研究。选择2020-01/2021-12在安阳市眼科医院拟行角膜屈光手术的近视患者120例240眼。根据手术治疗方式分为SMILE组64例128眼,经上皮准分子激光角膜切削术(TransPRK)组56例112眼。比较两组患者术后1、7 d,1、3、6 mo,1 a的裸眼视力、角膜生物力学、角膜内皮细胞数目、角膜后表面高度、角膜表面规则指数、手术并发症。结果:SMILE组患者术后1、7 d,1 mo裸眼视力均优于TransPRK组(均P<0.001),但两组术后3、6 mo,1 a均无差异(均P>0.05)。与术前相比,两组患者术后的角膜补偿眼压、模拟Goldmann眼压、角膜阻力因子、角膜滞后量呈先下降后升高趋势。SMILE组术后1、7 d,1 mo角膜补偿眼压、模拟Goldmann眼压、角膜阻力因子、角膜滞后量均高于TransPRK组(均P<0.05),但术后3、6 mo,1 a均无差异(均P>0.05)。手术前后两组患者角膜内皮细胞数目、角膜后表面高度均无差异(均P>0.05)。与术前相比,两组患者术后角膜表面规则指数呈先升高后降低趋势,但组间比较无差异(P>0.05)。两组患者术后并发症发生率比较无差异(P>0.05)。结论:相比TransPRK,SMILE对角膜生物力学的影响较小,早期视力恢复效果更好,两种手术的远期视力无差异,均有良好的安全性和有效性。

SMILE,FS-LASIK治疗术对高度近视患者角膜稳定性及视觉质量的影响

评估SMILE和FS-LASIK两种手术方式对高度近视患者角膜稳定性及视觉质量的影响。方法 采用回顾性分析选取我院于2020年6月-2021年6月期间收诊的96例高度近视患者,根据治疗方式分为SMILE组与FS-LASIK组,各48例。比较这两种方法对患者角膜稳定性和视觉质量的影响。结果 术后1、3mo的跟踪观察中,与术前相比,两组患者的角膜最薄点显著降低(p<0.05);而角膜后表面高度降低幅度无显著差异(p>0.05)。在术后1mo,SMILE组的角膜最薄点高度高于FS-LASIK组(p<0.05);术后3mo,SMILE组的该高度低于FS-LASIK组,差异不显著(p>0.05)。在术后1、3mo,SMILE组的角膜后表面高度普遍低于FS-LASIK组,无统计学意义(p>0.05)。术后1mo,两组患者客观散射指数(OSI)与术前比较升高,且SMILE组低于FS-LASIK组(p<0.05);术后3mo,两组患者OSI与术前比较升高,且SMILE组低于FS-LASIK组,无统计学差异(p>0.05)。术后1mo,两组患者的调制传递函数截止频率(MTF cut-off)较术前降低,且SMILE组高于FS-LASIK组(p<0.05);术后3mo,两组患者的MTF cut-off值较术前降低,SMILE组高于FS-LASIK组,无统计学差异(p>0.05)。SMILE组的斯特列比(SR)在术后1、3mo均高于FS-LASIK组,但无统计学差异(p>0.05)。结论 SMILE手术在术后早期对高度近视患者的视觉质量改善方面显示出一定的优势,特别是在OSI和MTF cut-off值方面。但就角膜稳定性而言,SMILE和FS-LASIK手术之间无显著差异。这表明SMILE手术是高度近视患者的一个更佳选择,尤其是在考虑早期视觉质量改善方面。

Ground-based and additional science support for SMILE

The joint European Space Agency and Chinese Academy of Sciences Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)mission will explore global dynamics of the magnetosphere under varying solar wind and interplanetary magnetic field conditions,and simultaneously monitor the auroral response of the Northern Hemisphere ionosphere.Combining these large-scale responses with medium and fine-scale measurements at a variety of cadences by additional ground-based and space-based instruments will enable a much greater scientific impact beyond the original goals of the SMILE mission.Here,we describe current community efforts to prepare for SMILE,and the benefits and context various experiments that have explicitly expressed support for SMILE can offer.A dedicated group of international scientists representing many different experiment types and geographical locations,the Ground-based and Additional Science Working Group,is facilitating these efforts.Preparations include constructing an online SMILE Data Fusion Facility,the discussion of particular or special modes for experiments such as coherent and incoherent scatter radar,and the consideration of particular observing strategies and spacecraft conjunctions.We anticipate growing interest and community engagement with the SMILE mission,and we welcome novel ideas and insights from the solar-terrestrial community.

Hybrid-Vlasov simulation of soft X-ray emissions at the Earth’s dayside magnetospheric boundaries

Solar wind charge exchange produces emissions in the soft X-ray energy range which can enable the study of near-Earth space regions such as the magnetopause,the magnetosheath and the polar cusps by remote sensing techniques.The Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)and Lunar Environment heliospheric X-ray Imager(LEXI)missions aim to obtain soft Xray images of near-Earth space thanks to their Soft X-ray Imager(SXI)instruments.While earlier modeling works have already simulated soft X-ray images as might be obtained by SMILE SXI during its mission,the numerical models used so far are all based on the magnetohydrodynamics description of the space plasma.To investigate the possible signatures of ion-kinetic-scale processes in soft Xray images,we use for the first time a global hybrid-Vlasov simulation of the geospace from the Vlasiator model.The simulation is driven by fast and tenuous solar wind conditions and purely southward interplanetary magnetic field.We first produce global X-ray images of the dayside near-Earth space by placing a virtual imaging satellite at two different locations,providing meridional and equatorial views.We then analyze regional features present in the images and show that they correspond to signatures in soft X-ray emissions of mirrormode wave structures in the magnetosheath and flux transfer events(FTEs)at the magnetopause.Our results suggest that,although the time scales associated with the motion of those transient phenomena will likely be significantly smaller than the integration time of the SMILE and LEXI imagers,mirror-mode structures and FTEs can cumulatively produce detectable signatures in the soft X-ray images.For instance,a local increase by 30%in the proton density at the dayside magnetopause resulting from the transit of multiple FTEs leads to a 12%enhancement in the line-of-sight-and time-integrated soft X-ray emissivity originating from this region.Likewise,a proton density increase by 14%in the magnetosheath associated with mirror-mode structures can result in an enhancement in the soft X-ray signal by 4%.These are likely conservative estimates,given that the solar wind conditions used in the Vlasiator run can be expected to generate weaker soft X-ray emissions than the more common denser solar wind.These results will contribute to the preparatory work for the SMILE and LEXI missions by providing the community with quantitative estimates of the effects of small-scale,transient phenomena occurring on the dayside.

On the apparent line-of-sight alignment of the peak X-ray intensity of the magnetosheath and the tangent to the magnetopause,as viewed by SMILE-SXI

The Soft X-ray Imager(SXI)on board the Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)spacecraft will be able to view the Earth’s magnetosheath in soft X-rays.Simulated images of the X-ray emission visible from the position of SMILE are created for a range of solar wind densities by using 3 years of the SMILE mission orbit,together with models of the expected X-ray emissivity from the Earth’s magnetosheath.Results from global magnetohydrodynamic simulations and a simple model for exospheric neutral densities are used to compare the locations of the lines of sight along which integrated soft X-ray intensities peak with the lines of sight lying tangent to surfaces(defined here to be the magnetopause)along which local soft X-ray intensities peak or exhibit their strongest gradients,or both,for strongly southward interplanetary magnetic field conditions when no depletion or low-latitude boundary layers are expected.Where,in the parameter space of the various times and seasons,orbital phases,solar wind conditions,and magnetopause models,the alignment of the X-ray emission peak with the magnetopause tangent is good,or is not,is presented.The main results are as follows.The spacecraft needs to be positioned well outside the magnetopause;low-altitude times near perigee are not good.In addition,there are seasonal aspects:dayside-apogee orbits are generally very good because the spacecraft travels out sunward at high altitude,but nightside-apogee orbits,behind the Earth,are bad because the spacecraft only rarely leaves the magnetopause.Dusk-apogee and dawnapogee orbits are intermediate.Dayside-apogee orbits worsen slightly over the first three mission years,whereas nightside-apogee orbits improve slightly.Additionally,many more times of good agreement with the peak-to-tangent hypothesis occur when the solar wind is in a high-density state,as opposed to a low-density state.In a high-density state,the magnetopause is compressed,and the spacecraft is more often a good distance outside the magnetopause.

Estimating the subsolar magnetopause position from soft X-ray images using a low-pass image filter

The Lunar Environment heliospheric X-ray Imager(LEXI)and Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)missions will image the Earth’s dayside magneto pause and cusps in soft X-rays after their respective launches in the near future,to specify glo bal magnetic reconnection modes for varying solar wind conditions.To suppo rt the success of these scientific missions,it is critical to develop techniques that extract the magnetopause locations from the observed soft X-ray images.In this research,we introduce a new geometric equation that calculates the subsolar magnetopause position(RS)from a satellite position,the look direction of the instrument,and the angle at which the X-ray emission is maximized.Two assumptions are used in this method:(1)The look direction where soft X-ray emissions are maximized lies tangent to the magnetopause,and(2)the magnetopause surface near the subsolar point is almost spherical and thus RSis nea rly equal to the radius of the magneto pause curvature.We create synthetic soft X-ray images by using the Open Geospace General Circulation Model(OpenGGCM)global magnetohydrodynamic model,the galactic background,the instrument point spread function,and Poisson noise.We then apply the fast Fourier transform and Gaussian low-pass filte rs to the synthetic images to re move noise and obtain accurate look angles for the soft X-ray pea ks.From the filte red images,we calculate RS and its accuracy for different LEXI locations,look directions,and solar wind densities by using the OpenGGCM subsolar magnetopause location as ground truth.Our method estimates RS with an accuracy of<0.3 RE when the solar wind density exceeds>10 cm-3.The accuracy improves for greater solar wind densities and during southward interplanetary magnetic fields.The method ca ptures the magnetopause motion during southwa rd interplaneta ry magnetic field turnings.Consequently,the technique will enable quantitative analysis of the magnetopause motion and help reveal the dayside reconnection modes for dynamic solar wind conditions.This technique will suppo rt the LEXI and SMILE missions in achieving their scientific o bjectives.

SMILE soft X-ray Imager flight model CCD370 pre-flight device characterisation

Throughout the SMILE mission the satellite will be bombarded by radiation which gradually damages the focal plane devices and degrades their performance.In order to understand the changes of the CCD370s within the soft X-ray Imager,an initial characterisation of the devices has been carried out to give a baseline performance level.Three CCDs have been characterised,the two flight devices and the flight spa re.This has been carried out at the Open University in a bespo ke cleanroom measure ment facility.The results show that there is a cluster of bright pixels in the flight spa re which increases in size with tempe rature.However at the nominal ope rating tempe rature(-120℃) it is within the procure ment specifications.Overall,the devices meet the specifications when ope rating at -120℃ in 6 × 6 binned frame transfer science mode.The se rial charge transfer inefficiency degrades with temperature in full frame mode.However any charge losses are recovered when binning/frame transfer is implemented.

Global hybrid simulations of soft X-ray emissions in the Earth’s magnetosheath

Earth’s magnetopause is a thin boundary separating the shocked solar wind plasma from the magnetospheric plasmas,and it is also the boundary of the solar wind energy transport to the magnetosphere.Soft X-ray imaging allows investigation of the large-scale magnetopause by providing a two-dimensional(2-D)global view from a satellite.By performing 3-D global hybrid-particle-in-cell(hybrid-PIC)simulations,we obtain soft X-ray images of Earth’s magnetopause under different solar wind conditions,such as different plasma densities and directions of the southward interplanetary magnetic field.In all cases,magnetic reconnection occurs at low latitude magnetopause.The soft X-ray images observed by a hypothetical satellite are shown,with all of the following identified:the boundary of the magnetopause,the cusps,and the magnetosheath.Local X-ray emissivity in the magnetosheath is characterized by large amplitude fluctuations(up to 160%);however,the maximum line-of-sight-integrated X-ray intensity matches the tangent directions of the magnetopause well,indicating that these fluctuations have limited impact on identifying the magnetopause boundary in the X-ray images.Moreover,the magnetopause boundary can be identified using multiple viewing geometries.We also find that solar wind conditions have little effect on the magnetopause identification.The Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)mission will provide X-ray images of the magnetopause for the first time,and our global hybrid-PIC simulation results can help better understand the 2-D X-ray images of the magnetopause from a 3-D perspective,with particle kinetic effects considered.

Tomographic reconstruction of the Earth’s magnetosheath from multiple spacecraft:a theoretical study

Following our earlier work on tomographic reconstruction of the magnetosheath soft X-ray emissions with superposed epoch analysis of many images recorded from a single spacecraft we now explore the instantaneous reconstruction of the magnetosheath and magnetopause using a few images recorded simultaneously from a few spacecraft.This work is motivated by the prospect of possibly having two or three soft X-ray imagers in space in the coming years,and that many phenomena which occur at the magnetopause boundary,such as reconnection events and pressure pulse responses,do not lend themselves as well to superposed epoch analysis.If the reconstruction is successful-which we demonstrate in this paper that it can be-this collection of imagers can be used to reconstruct the magnetosheath and magnetopause from a single image from each spacecraft,allowing for high time resolution reconstructions.In this paper we explore the reconstruction using,two,three,and four spacecraft.We show that the location of the subsolar point of the magnetopause can be determined with just two satellites,and that volume emissions of soft X-rays,and the shape of the boundary,can be reconstructed using three or more satellites.

Deformations at Earth’s dayside magnetopause during quasi-radial IMF conditions:Global kinetic simulations and Soft X-ray Imaging

The Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)is a joint mission of the European Space Agency(ESA)and the Chinese Academy of Sciences(CAS).Primary goals are investigating the dynamic response of the Earth's magnetosphere to the solar wind(SW)impact via simultaneous in situ magnetosheath plasma and magnetic field measurements,X-Ray images of the magnetosheath and magnetic cusps,and UV images of global auroral distributions.Magnetopause deformations associated with magnetosheath high speed jets(HSJs)under a quasi-parallel interplanetary magnetic field condition are studied using a threedimensional(3-D)global hybrid simulation.Soft X-ray intensity calculated based on both physical quantities of solar wind proton and oxygen ions is compared.We obtain key findings concerning deformations at the magnetopause:(1)Magnetopause deformations are highly coherent with the magnetosheath HSJs generated at the quasi-parallel region of the bow shock,(2)X-ray intensities estimated using solar wind h+and self-consistentO7+ions are consistent with each other,(3)Visual spacecraft are employed to check the discrimination ability for capturing magnetopause deformations on Lunar and polar orbits,respectively.The SMILE spacecraft on the polar orbit could be expected to provide opportunities for capturing the global geometry of the magnetopause in the equatorial plane.A striking point is that SMILE has the potential to capture small-scale magnetopause deformations and magnetosheath transients,such as HSJs,at medium altitudes on its orbit.Simulation results also demonstrate that a lunar based imager(e.g.,Lunar Environment heliospheric X-ray Imager,LEXI)is expected to observe a localized brightening of the magnetosheath during HSJ events in the meridian plane.These preliminary results might contribute to the pre-studies for the SMILE and LEXI missions by providing qualitative and quantitative soft X-ray estimates of dayside kinetic processes.

Using restored two-dimensional X-ray images to reconstruct the three-dimensional magnetopause

Astronomical imaging technologies are basic tools for the exploration of the universe,providing basic data for the research of astronomy and space physics.The Soft X-ray Imager(SXI)carried by the Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)aims to capture two-dimensional(2-D)images of the Earth’s magnetosheath by using soft X-ray imaging.However,the observed 2-D images are affected by many noise factors,destroying the contained information,which is not conducive to the subsequent reconstruction of the three-dimensional(3-D)structure of the magnetopause.The analysis of SXI-simulated observation images shows that such damage cannot be evaluated with traditional restoration models.This makes it difficult to establish the mapping relationship between SXIsimulated observation images and target images by using mathematical models.We propose an image restoration algorithm for SXIsimulated observation images that can recover large-scale structure information on the magnetosphere.The idea is to train a patch estimator by selecting noise–clean patch pairs with the same distribution through the Classification–Expectation Maximization algorithm to achieve the restoration estimation of the SXI-simulated observation image,whose mapping relationship with the target image is established by the patch estimator.The Classification–Expectation Maximization algorithm is used to select multiple patch clusters with the same distribution and then train different patch estimators so as to improve the accuracy of the estimator.Experimental results showed that our image restoration algorithm is superior to other classical image restoration algorithms in the SXI-simulated observation image restoration task,according to the peak signal-to-noise ratio and structural similarity.The restoration results of SXI-simulated observation images are used in the tangent fitting approach and the computed tomography approach toward magnetospheric reconstruction techniques,significantly improving the reconstruction results.Hence,the proposed technology may be feasible for processing SXI-simulated observation images.