激光共聚焦拉曼光谱法测定防晒剂经皮渗透作用及其应用研究

基于激光共聚焦拉曼光谱技术,采用皮肤成分分析仪结合多元线性回归分析方法,建立了皮肤中防晒剂深度分布及经皮渗透量的实时、在体测试方法。以志愿者手臂为实验对象,针对常见的三种防晒剂甲氧基肉桂酸乙基己酯(OMC)、二乙氨羟苯甲酰基苯甲酸己酯(DBHB)和乙基己基三嗪酮(EHT),测试并分析了手臂不同皮肤区域经皮渗透能力的一致性,同时比较了不同配方工艺防晒乳的防晒剂经皮渗透作用。结果表明,手臂内侧的不同区域皮肤防晒剂经皮渗透量的相对标准偏差均小于15%,证明可用于不同防晒剂产品的经皮渗透对比;比较油包水防晒乳和纳米乳化工艺的防晒乳中防晒剂的经皮渗透作用,发现经过1 h的皮肤渗透,纳米乳化工艺的防晒乳相比油包水型防晒乳液,三种防晒剂在皮肤的经皮渗透量均降低约60%,而且EHT的经皮渗透深度相对更浅。该方法在防晒剂经皮渗透作用研究中得到了有效的应用,可为化妆品的经皮吸收提供方法参考。

State-selective charge exchange cross sections in collisions of highly-charged sulfur ions with helium and molecular hydrogen

The state-selective cross section data are useful for understanding and modeling the x-ray emission in celestial observations.In the present work,using the cold target recoil ion momentum spectroscopy,for the first time we investigated the state-selective single electron capture processes for S^(q+)–He and H_(2)(q=11–15)collision systems at an impact energy of q×20 keV and obtained the relative state-selective cross sections.The results indicate that only a few principal quantum states of the projectile energy level are populated in a single electron capture process.In particular,the increase of the projectile charge state leads to the population of the states with higher principal quantum numbers.It is also shown that the experimental averaged n-shell populations are reproduced well by the over-barrier model.The database is openly available in Science Data Bank at 10.57760/sciencedb.j00113.00091.

The n-resolved single-electron capture in slow O^(6+)-Ne collisions

A study of single-electron capture(SEC) in 18-240 keV O^(6+)-Ne collisions has been conducted employing a combination of experimental and theoretical methodologies.Utilizing a reaction microscope,state-selective SEC cross sections and projectile scattering angle distributions were obtained.The translational energy spectra for SEC reveal the prevailing capture into n=3 states of the projectile ion,with a minor contribution from n=4 states.Notably,as the projectile's energy increases,the relative contribution of SEC n=4 states increases while that of SEC n=3 states diminishes.Furthermore,we computed state-selective relative cross sections and angular differential cross sections employing the classical molecular Coulomb over-the-barrier model(MCBM) and the multichannel Landau-Zener(MCLZ) model.A discernible discrepancy between the state-selective cross sections from the two theoretical models is apparent for the considered impact energies.However,regarding the angular differential cross sections,an overall agreement was attained between the current experimental results and the theoretical results from the MCLZ model.

Estimating the yield stress of soft materials via laser-induced breakdown spectroscopy

Taking three typical soft samples prepared respectively by loose packings of 77-,95-,and 109-μm copper grains as examples,we perform an experiment to investigate the energy-dependent laser-induced breakdown spectroscopy(LIBS)of soft materials.We discovered a reversal phenomenon in the trend of energy dependence of plasma emission intensity:increasing initially and then decreasing separated by a well-defined critical energy.The trend reversal is attributed to the laser-induced recoil pressure at the critical energy just matching the sample's yield strength.As a result,a one-to-one correspondence can be well established between the samples'yield stress and the critical energy that is easily obtainable from LIBS measurements.This allows us to propose an innovative method for estimating the yield stress of soft materials via LIBS with attractive advantages including in-situ remote detection,real-time data collection,and minimal destructive to sample.

Estimating the grain size of microgranular material using laser-induced breakdown spectroscopy combined with machine learning algorithms

Recent work has validated a new method for estimating the grain size of microgranular materials in the range of tens to hundreds of micrometers using laser-induced breakdown spectroscopy(LIBS).In this situation,a piecewise univariate model must be constructed to estimate grain size due to the complex dependence of the plasma formation environment on grain size.In the present work,we tentatively construct a unified calibration model suitable for LIBS-based estimation of those grain sizes.Specifically,two unified multivariate calibration models are constructed based on back-propagation neural network(BPNN)algorithms using feature selection strategies with and without considering prior information.By detailed analysis of the performances of the two multivariate models,it was found that a unified calibration model can be successfully constructed based on BPNN algorithms for estimating the grain size in the range of tens to hundreds of micrometers.It was also found that the model constructed with a priorguided feature selection strategy had better prediction performance.This study has practical significance in developing the technology for material analysis using LIBS,especially when the LIBS signal exhibits a complex dependence on the material parameter to be estimated.

Laser-induced breakdown spectroscopy as a method for millimeter-scale inspection of surface flatness

A non-contact method for millimeter-scale inspection of material surface flatness via Laser-Induced Breakdown Spectroscopy(LIBS)is investigated experimentally.The experiment is performed using a planished surface of an alloy steel sample to simulate its various flatness,ranging from 0 to 4.4 mm,by adjusting the laser focal plane to the surface distance with a step length of 0.2 mm.It is found that LIBS measurements are successful in inspecting the flatness differences among these simulated cases,implying that the method investigated here is feasible.It is also found that,for achieving the inspection of surface flatness within such a wide range,when univariate analysis is applied,a piecewise calibration model must be constructed.This is due to the complex dependence of plasma formation conditions on the surface flatness,which inevitably complicates the inspection procedure.To solve the problem,a multivariate analysis with the help of Back-Propagation Neural Network(BPNN)algorithms is applied to further construct the calibration model.By detailed analysis of the model performance,we demonstrate that a unified calibration model can be well established based on BPNN algorithms for unambiguous millimeter-scale range inspection of surface flatness with a resolution of about 0.2 mm.

Absolute dielectronic recombination rate coefficients of highly charged ions at the storage ring CSRm and CSRe

Dielectronic recombination(DR)is one of the dominant electron-ion recombination mechanisms for most highly charged ions(HCIs)in cosmic plasmas,and thus,it determines the charge state distribution and ionization balance therein.To reliably interpret spectra from cosmic sources and model the astrophysical plasmas,precise DR rate coefficients are required to build up an accurate understanding of the ionization balance of the sources.The main cooler storage ring(CSRm)and the experimental cooler storage ring(CSRe)at the Heavy-Ion Research Facility in Lanzhou(HIRFL)are both equipped with electron cooling devices,which provide an excellent experimental platform for electron-ion collision studies for HCIs.Here,the status of the DR experiments at the HIRFL-CSR is outlined,and the DR measurements with Na-like Kr25^(+)ions at the CSRm and CSRe are taken as examples.In addition,the plasma recombination rate coefficients for Ar12^(+),14^(+),Ca14^(+),16^(+),17^(+),Ni19^(+),and Kr25^(+)ions obtained at the HIRFL-CSR are provided.All the data presented in this paper are openly available at https://doi.org/10.57760/sciencedb.j00113.00092.

Value of big data to finance:observations on an internet credit Service Company in China

Background:his paper presents a case study on 100Credit,an Internet credit service provider in China.100Credit began as an IT company specializing in e-commerce recommendation before getting into the credit rating business.The company makes use of Big Data on multiple aspects of individuals’online activities to infer their potential credit risk.Methods:Based on 100Credit’s business practices,this paper summarizes four aspects related to the value of Big Data in Internet credit services.Results:1)value from large data volume that provides access to more borrowers;2)value from prediction correctness in reducing lenders’operational cost;3)value from the variety of services catering to different needs of lenders;and 4)value from information protection to sustain credit service businesses.Conclusion:The paper also discusses the opportunities and challenges of Big Databased credit risk analysis,which needs to be improved in future research and practice.

Atomic structure and collision dynamics with highly charged ions

The research progresses on the investigations of atomic structure and collision dynamics with highly charged ions based on the heavy ion storage rings and electron ion beam traps in recent 20 years are reviewed.The structure part covers test of quantum electrodynamics and electron correlation in strong Coulomb field studied through dielectronic recombi-nation spectroscopy and VUV/x-ray spectroscopy.The collision dynamics part includes charge exchange dynamics in ion-atom collisions mainly in Bohr velocity region,ion-induced fragmentation mechanisms of molecules,hydrogen-bound and van de Waals bound clusters,interference,and phase information observed in ion-atom/molecule collisions.With this achievements,two aspects of theoretical studies related to low energy and relativistic energy collisions are presented.The applications of data relevant to key atomic processes like dielectronic recombination and charge exchanges involving highly charged ions are discussed.At the end of this review,some future prospects of research related to highly charged ions are proposed.

Poly(ether ether ketone ketone) based imidazolium as anion exchange membranes for alkaline fuel cells

An imidazolium functionalized poly(ether ether ketone ketone)(PEEKK-DIm OH)anion exchange membrane(AEM)readily soluble in certain low-boiling-point solvents(isopropanol)is prepared.The solubility results are consistent with the results of molecular dynamics simulations.By varying the chloromethylation reaction temperature or concentrated sulfuric acid concentration of PEEKK,the degrees of chloromethylation of PEEKK are changed from 54% to 92%,the corresponding PEEKK-DIm OH AEMs with the ion exchange capacities(IECs)of 1.14–1.65 mmol·g^(-1).The PEEKK-DIm OH 92% AEM shows high hydroxide conductivity(31 m S·cm^(-1)),suitable water uptake(94%)and acceptable swelling ratio(39%)at 60°C.In addition,the PEEKK-DIm OH AEMs possess good thermal and alkaline stability.The maximum power density(46.16 mW·cm^(-2))of fuel cell prepared with PEEKK-DIm OH 92%AEM as exchange membrane and ionomer is much higher than that with commercial AHA membranes.All the above results indicate that the PEEKK used in this study is a promising AEM matrix material for alkaline fuel cells.

Geometric structure of N_(2)O^(q+)(q=5,6)studied by Ne^(8+)ion-induced Coulomb explosion imaging

We report the study on the complete three-body Coulomb explosion(CE)of N_(2)O^(q+)(q=5,6)induced by 56-keV/u Ne8+ion collision with N2O gaseous molecule.Six CE channels for N_(2)O^(5+)and seven for N_(2)O^(6+)are identified by measuring three ionic fragments and the charge-changed projectile in quadruple coincidence.Correspondingly the kinetic energy release(KER)and momentum correlation angle(MCA)distributions of three ionic fragments for each of the CE channels are also deduced.Numerical computation is presented to reconstruct the geometric structure of N_(2)O^(q+0prior to dissociation based on the measured KER and MCA.The N–N and N–O bond lengths and the N–N–O bond angles of N_(2)O^(q+)for each of the channels are determined.

旋流筛板式气固挡板流化床内压力脉动特性

在表观气速Ug=0.04～1.14 m/s时,采用旋流筛板构型的挡板式内构件,通过对比分析旋流筛板式气固挡板流化床与自由床内流动现象、压差脉动标准偏差和压力脉动标准偏差等参数,确定了旋流筛板式气固挡板流化床能有效破碎气泡的流动与操作条件。结果表明,构件下方区域颗粒随表观气速增加而不断转移至构件上方床层,造成构件下方区域密相床层高度持续降低,该区域出现3种流动状态并直接决定构件是否能破碎气泡。当Ug<0.44 m/s时,构件下方区域密相床层料位较高,形成下部为密相床层、上部为密相与大气泡交替通过构件的鼓泡床,此时构件具有抑制气泡生长并破碎气泡的作用,全床压差脉动及压力脉动标准偏差低于相同条件下的自由床;当0.44≤Ug<0.66 m/s时,密相床层料位较低,形成下部为密相床层、上部为单一稀相的湍动床,此时构件不再直接抑制气泡生长或破碎气泡,但构件下方密相床层的存在能降低构件下方及构件上方一定高度内床层的压力脉动强度;当Ug≥0.66 m/s后,密相床层完全消失,形成气体为连续相的稀相流化状态,构件不能破碎气泡、降低床层压力和压差脉动强度。

“走出去”企业利用税收协定情况分析及建议

"一带一路"倡议对推动我国经济发展和扩大对外合作影响深远,也为我国企业"走出去"创造了难得的历史机遇。在这一过程中,税收协定越来越成为营商环境的重要体现之一,在避免双重征税、处理跨境税收问题、解决涉税争议等方面发挥了积极作用,逐渐成为企业"走出去"的重要保障。本文分析双边税收协定的主要条款,并结合实际指出"走出去"企业在利用税收协定中存在的问题,最后提出相关建议。

纳米管表面和自润湿溶液相耦合的传热性能

采用阳极氧化法在光滑钛板表面制备了高度有序的纳米管表面,利用扫描电镜、原子力显微镜和全自动接触角测量仪表征了纳米管表面和光滑表面的形貌及表面特性,配制自润湿溶液并进行热物性测定,将不同的加热面(光滑表面和纳米管表面)与不同工质(蒸馏水和自润湿溶液)组合进行池沸腾实验,从不同角度对比了不同组合工况的传热效果,从微观和宏观两方面对纳米管表面和自润湿溶液耦合强化传热的机理进行了分析。结果表明,具有超亲水性和较大粗糙度的纳米管表面与自润湿性溶液耦合时,最大传热系数和临界热流密度较高,分别为11.963 kW/(m2?℃)和623.706 kW/m2,比光滑表面与蒸馏水的常规组合传热分别提高了84.1%和143.8%。纳米管表面和自润湿溶液对系统的最大传热系数和临界热流密度强化作用稍有不同,二者协调强化沸腾传热性能。纳米管表面具有更多的有效汽化核心、更大的粗糙度和更好的润湿性,结合自润湿溶液特殊的表面张力特性形成冷热液体微循环,促进冷热液体运动,及时进行二次润湿,大幅减小气泡脱离直径,提高其脱离频率,出现微气泡,增加了对系统的扰动,有效增强了传热性能,是提高系统最大传热系数和临界热流密度的主要原因。

Preparation of SGO-modified nanofiltration membrane and its application in SO_4^(2-) and Cl^- separation in salt treatment

The lack of fresh water in the world makes the search for an effective method to decontaminate water an urgent priority.An important step is to remove different multivalent ions in salt treatment.Nanofiltration(NF)has been used for treating water containing different kinds of salts.In this work,sulfonate group-modified graphene oxide(SGO)was prepared,and added during the interfacial polymerization(IP)reaction to prepare SGO-modifiedNF membranes(PA-SGO).The chemical composition,structure and surface properties of PA and PA-SGO membranes were characterized by FT-IR,XPS,SEM,AFM,contact angle and zeta potential measurements.Their water flux,salt rejection and antifouling abilities were investigated systematically.The testing results showed that the water flux of PA-SGO(0.03%SGO)was 45.85 LMH under a pressure of 0.2 MPa,and the salt rejection varied in the order of Na_2SO_4(98.99%)>MgSO_4(91.25%)>MgCl_2(42.27%)>NaCl(21.96%).An anti-fouling experiment indicated that the PA-SGO membrane had good anti-fouling properties because of its decreased roughness and increased hydrophilicity and electronegativity.The PA-SGO membrane has good potential for use in removing salt ions from water.

Constraint strength and axial/radial particle velocity profiles for an integrated riser outlet

To study axial/radial profiles of particle velocity in the affected region of an integrated riser outlet, a cold model was developed for the integrated riser reactor combining the gas-solid distributor with the fluidized bed. Constraints, related to the gas-solid distributor and the upper fluidized bed, imposed on the particle flow in the riser outlet region, were investigated experimentally. The experimental results showed that with increasing superficial gas velocity, these constraints have strong influences on particle flow behavior, the particle circulation flux in the riser, and the height of the static bed material of the upper fluidized bed. When the constraints have greater prominence, the axial profile of the cross-sectionally averaged particle velocity in the outlet region initially increases and then decreases, the rate of decrease being proportional to the constraint strength. Along the radial direction of the outlet section, the region where the local particle velocity profile tends to decrease appears near the dimensionless radius r/R = 0.30 initially and then, with increasing constraint strength, gradually extends to the whole section from the inner wall. Based on the experimental data, an empirical model describing the constraint strength was established. The average relative error of the model is within 7.69%.

构建战略型集约化财务管控体系——中国石化打造世界一流企业财务管理体系的探索与实践

中国石油化工集团有限公司(以下简称“中国石化”)全面贯彻落实国务院国资委《关于中央企业加快建设世界一流财务管理体系的指导意见》的要求,紧扣集团公司世界领先发展方略,基于多年来持续推进财务转型的探索实践经验,提出构建战略型集约化财务管控体系作为建设世界一流财务的主攻方向,形成了具有中国石化特色的“1238”财务管控体系,有效助推企业可持续高质量发展。

创造性团队中的地位竞争动机对探索式学习的作用机制——基于组织公平的调节视角

在创造性团队中,探索式学习是提升整体绩效的重要方式,而源于员工内心需求的地位竞争动机对其会产生重要影响。本文选取江苏某大型文化企业29个创制项目团队的配对数据为样本,通过层级回归分析,探讨了地位竞争动机对探索式学习的作用机制。研究发现,基于威望的地位竞争动机与探索式学习呈正向相关关系,基于支配的地位竞争动机与探索式学习呈负向相关关系;团队知识共享在地位竞争动机和探索式学习之间的关系中起中介作用;组织公平在地位竞争动机与团队知识共享之间的关系中起调节作用。具体而言,程序公平在基于威望的地位竞争动机和团队知识共享之间的关系中起正向调节作用,在基于支配的地位竞争动机和团队知识共享之间的关系中起负向调节作用,分配公平只在基于威望的地位竞争动机和团队知识共享之间的关系中起正向调节作用。

Industrial-scale investigations on effects of tertiary-air declination angle on combustion and steam temperature characteristics in a 350-MW supercritical down-fired boiler

Industrial-scale experiments were conducted to study the effects of tertiary air declination angle(TDA)on the coal combustion and steam temperature characteristics in the first 350-MW supercritical down-fired boiler in China with the multiple-injection and multiple-staging combustion(MIMSC)technology at medium and high loads.The experimental results indicated that as the TDA increased from 0°to 15°,the overall gas temperature in the lower furnace rose and the symmetry of temperature field was enhanced.The ignition distance of the fuel-rich coal/air flow decreased.In near-burner region,the concentration of O2 decreased while the concentrations of CO and NO increased.The concentration of NO decreased in near-tertiary-air region.The carbon in fly ash decreased significantly from 8.40%to 6.45%at a load of 260 MW.At a TDA of 15°,the ignition distances were the shortest(2.07 m and 1.73 m)at a load of 210 MW and 260 MW,respectively.The main and reheat steam temperatures were the highest(557.2℃ and 559.4℃ at a load of 210 MW,558.4℃ and 560.3℃ at a load of 260 MW).The carbon in fly ash was the lowest(4.83%)at a load of 210 MW.On changing the TDA from 15°to 25°,the flame kernel was found to move downward and the main and reheat steam temperatures dropped obviously.The change of TDA has little effect on NO_(x) emissions(660–681 mg/m^(3) at 6%O_(2)).In comprehensive consideration of the pulverized coal combustion characteristics and the unit economic performance,an optimal TDA of 15°is recommended.