二硫化硒的制备及其在洗护领域的应用研究进展

二硫化硒是硫化硒(SemSn)混合物的统称,具有多元环结构,不同环结构之间可相互转化。二硫化硒常用熔融法、化学法合成,而纳米二硫化硒常用电化学法和绿色合成法制备,其常用的表征方法有X射线衍射分析(XRD)、扫描电镜(SEM)、透射电镜(TEM)、X射线能量光谱仪(EDS)、动态光散射(DLS)和傅里叶红外光谱(FT-IR)。二硫化硒属于细胞生长抑制剂和角质溶解剂,具有抗皮脂溢出、抗真菌及细菌的作用,能抑制核分裂,造成表皮细胞更替减少,起到止痒、消炎、减少脱屑的作用,常用于治疗脂溢性皮炎和花斑藓。硫和硒都是具有多种原子价位的元素,既可表现还原性,又可表现氧化性,其潜能让二硫化硒的分子结构、性能特点及应用开发成为研究热点。本文综述了二硫化硒性质、结构特点、制备方法、表征及其在洗护领域的应用,并对其未来发展趋势进行了展望。

Anomalous{1012}tensile twinning and subsequent detwinning in a friction stir processed carbon fiber-reinforced Mg composite

1.Main text Owing to their low density and high specific strength,magnesium alloys and magnesium-based composites have great potential as structure metal materials in applications where lightweight matters[1–4].Deformation twins[5],especially the{1012}tension twins(also called tensile or extension twins)with a low critical resolved shear stress(CRSS)[6],are commonly observed in Mg alloys.They can provide the much-needed deformation along the c-axis in their hcp structure resulting from the very few easily activated slip systems in this crystal structure[7].The tensile twinning activation usually follows the macroscopic Schmid factor law[2],i.e.,the twin variant with the highest Schmid factor occurs,and it only appears when its Schmid factor is positive.

水溶性聚合物对液晶乳液性能的影响

探究了海藻酸钠、黄原胶、卡波姆940、聚丙烯酸钠等四种水溶性聚合物对液晶乳液性能的影响,通过稳定性、热失重、流变学等实验进行考察。结果表明:添加卡波姆940对液晶结构与粒径无明显影响,离心稳定性表现较佳;黄原胶和卡波姆940对液晶乳液的室温储存有一定帮助且结合水含量占比最大,液晶含量多;流变学结果表明,添加卡波姆940会增加乳液的表观黏度、触变环面积与黏弹性,使液晶胶网抵抗外力应变的能力变强且不易发生形变。

Retrospective Analysis of External Quality Assessment Data of Humoral (Except Feces) Morphology in Guangxi from 2010 to 2022

[Objectives] The study aims to improve the ability of inspectors to recognize humoral morphology and provide data reference for the improvement of EQA work of humoral morphology by Guangxi Clinical Laboratory Center. [Methods] A retrospective analysis was made on the EQA of humoral morphology by Guangxi Clinical Laboratory Center from 2010 to 2022, and the number of participating laboratories, the rate of return, sample types and maps of EQA of humoral morphology such as urine sediment, vaginal secretions and so on(except feces), and the reasons for the high error rate of the results of the participating laboratories were analyzed. [Results] The number of laboratories participating in the assessment of humoral morphology increased from 98 in 2010 to 371 in 2022. Except for 2011(90.98%), the rate of return was more than 94%, and the highest rate of return was up to 100%. A total of 119 pictures of EQA of humoral morphology were studied, including 101 urine sediment smears, 13 vaginal secretions smears and 5 other smears. The types of specimens were relatively comprehensive. The distribution of the maps was basically reasonable. The urinary sediment was mainly composed of crystalline salts, followed by tubes, and cells and fungi ranked third. The coverage was relatively complete. The error rate of return results from high to low were bacteria(error rate was equal to 40%), tubes and crystalline salts(error rate was close to 29%), and cells and fungi(error rate was about 14%). The main cases with high error rate of return results are as follows: the difference between different tubes was not clear, and the diversity of crystal morphology was not understood enough;the phase division of cells in the same system was wrong. [Conclusions] The analysis and summary of the reasons for the high error rate of the data and results of Guangxi's EQA of humoral morphology is helpful for laboratory physicians to improve their awareness of morphological examination and identify clearly the error type and blurred concept, and lays a foundation for Guangxi Clinical Laboratory Center to carry out EQA of humoral morphology more specifically.

耐酸纳米微球的研发及CO_(2)驱封窜性能研究

针对长庆低渗透油藏CO_(2)驱出现的窜流难题,以丙烯酰胺(AM)、4-苯乙烯磺酸钠(SSS)和二甲基二烯丙基氯化铵(DMDAAC)为共聚单体,N,N’-亚甲基双丙烯酰胺(MBA)为交联剂,亚硫酸氢钠(SHS)和过硫酸铵(APS)为引发剂,通过反相微乳液聚合法研发了一种耐酸纳米微球(AR-NS)。采用红外光谱(FTIR)、扫描电镜(SEM)、热重(TG)及流变仪对产物的结构、形貌和性能进行了分析。结果表明,合成产物在乳液中为高分散度的纳米微球,其平均初始粒径为255 nm。在酸性地层水条件下,耐酸纳米微球的膨胀倍数为13.8倍而普通微球膨胀倍数仅为3.7倍;油藏温度85℃条件下、质量浓度为5 000 mg/L时耐酸纳米微球悬浮液黏度仅为0.56 mPa·s,具有优异的注入性;低渗裂缝岩心超临界CO_(2)驱封窜实验表明,耐酸纳米微球注入后裂缝性岩心的封堵率达95.41%,采收率提高了21.03%,耐酸纳米微球在低渗CO_(2)驱油藏中具有优异的封窜效果。

Flexible broadband polarization converter based on metasurface at microwave band

A flexible broadband linear polarization converter is proposed based on the metasurface operating at microwave band.To achieve bandwidth extension property, long and short metallic arc wires, as well as the metallic disks placed over a ground plane, are combined into the polarizer, which can generate three neighboring resonances.Due to the combination of the first two resonances and the optimized size and thickness of the unit cell, the polarization converter can have a weak incident angle dependence.Both simulated and measured results confirm that the average polarization conversion ratio is over 85% from 11.3 GHz to 20.2 GHz within a broad range of incident angle from 0°to 45°.Moreover, the proposed polarization converter based on flexible substrates can be applied for conformal design.The simulation and experiment results demonstrate that our designed polarizer still keeps high polarization conversion efficiency, even when it adheres to convex cylindrical surfaces.The periodic metallic structure of the designed polarizer has great potential application values in the microwave, terahertz, and optic regimes.

Exploring the effect of aggregation-induced emission on the excited state intramolecular proton transfer for a bis-imine derivative by quantum mechanics and our own n-layered integrated molecular orbital and molecular mechanics calculations

We theoretically investigate the excited state intramolecular proton transfer(ESIPT) behavior of the novel fluorophore bis-imine derivative molecule HNP which was designed based on the intersection of 1-(hydrazonomethyl)-naphthalene-2-ol and 1-pyrenecarboxaldehyde. Especially, the density functional theory(DFT) and time-dependent density functional theory(TDDFT) methods for HNP monomer are introduced. Moreover, the "our own n-layered integrated molecular orbital and molecular mechanics"(ONIOM) method(TDDFT:universal force field(UFF)) is used to reveal the aggregation-induced emission(AIE) effect on the ESIPT process for HNP in crystal. Our results confirm that the ESIPT process happens upon the photoexcitation for the HNP monomer and HNP in crystal, which is distinctly monitored by the optimized geometric structures and the potential energy curves. In addition, the results of potential energy curves reveal that the ESIPT process in HNP will be promoted by the AIE effect. Furthermore, the highest occupied molecular orbital(HOMO) and lowest unoccupied molecular orbital(LUMO) for the HNP monomer and HNP in crystal have been calculated. The calculation demonstrates that the electron density decrease of proton donor caused by excitation promotes the ESIPT process. In addition, we find that the variation of atomic dipole moment corrected Hirshfeld population(ADCH) charge for proton acceptor induced by the AIE effect facilitates the ESIPT process. The results will be expected to deepen the understanding of ESIPT dynamics for luminophore under the AIE effect and provide insight into future design of high-efficient AIE compounds.

Electron-irradiation-facilitated production of chemically homogenized nanotwins in nanolaminated carbides

Twin boundaries have been exploited to stabilize ultrafine grains and improve mechanical properties of nanomaterials.The production of the twin boundaries and nanotwins is however prohibitively challenging in carbide ceramics.Using a scanning transmission electron microscope as a unique platform for atomic-scale structure engineering,we demonstrate that twin platelets could be produced in carbides by engineering antisite defects.The antisite defects at metal sites in various layered ternary carbides are collectively and controllably generated,and the metal elements are homogenized by electron irradiation,which transforms a twin-like lamellae into nanotwin platelets.Accompanying chemical homogenization,α-Ti_(3)AlC_(2) transforms to unconventionalβ-Ti_(3)AiC_(2).The chemical homogeneity and the width of the twin platelets can be tuned by dose and energy of bombarding electrons.Chemically homogenized nanotwins can boost hardness by~45%.Our results provide a new way to produce ultrathin(<5 nm)nanotwin platelets in scientifically and technologically important carbide materials and showcase feasibility of defect engineering by an angstrom-sized electron probe.

Single-atom cobalt catalysts for chemoselective hydrogenation of nitroarenes to anilines

Single-atomic catalysts(SACs)caught considerable attention due to their unique structural properties,complete exposed active site,and 100%atom utilization efficiency with remarkable catalytic activity.Mesoporous single-atomic cobalt catalyst with Co-N_(4) active sites was synthesized by using nitrogen-doped graphene derived from acrylonitrile.Single-atomic cobalt was observed by aberration-corrected high-angle annular dark-field scanning transmission electron microscopy(HAADF-STEM)in Co@Nx-C-800.Notably,the density functional theory(DFT)calculation and the extended X-ray absorption fine structures(EXAFS)fitting results indicate that the coordination structure of Co-N is four-coordinated.In this work,the practical hydrogenation of nitroarenes to anilines enabled by Co@Nx-C-800 was established with excellent yields and selectivity,which proved its advantages and potential applications.

Effects of trace elements on mechanical properties of the TiZrHfNb high-entropy alloy

Refractory high-entropy alloys have great potential to be utilized as high-temperature materials,and the repeatability and reproducibility of their mechanical properties are critical for practical applications.In this work,nevertheless,we found that the mechanical properties of the TiZrHfNb HEA greatly varied with the content of impurities in the samples even using high-purity raw materials.Specifically,the oxygen impurity is mainly responsible for the increment of the yield stress due to the strong interstitial hardening effect,whilst the ductility deterioration closely associates with the content of metalloid elements B,C,and Si.Our analysis reveals that the metalloid elements not only tend to segregate at grain boundaries but also enhance the aggregation of Zr and Ti.Such co-segregation induced the formation of strong(Zr,Ti)-metalloid bonds,resulting in grain boundary embrittlement and brittle fracture.Our current work demonstrates that the impurity contents in refractory HEAs need to be strictly controlled during production in order to improve their stability of mechanical performance.

近红外二区发射AIE材料光动力-光热双模式协同治疗

聚集诱导发光材料因其出色的光学特性、良好的生物相容性、高活性氧产率以及优异的光热转换能力等特点,在光动力、光热治疗领域表现出巨大的应用潜力。然而,传统的荧光材料由于发射波长较短存在组织穿透性差等问题,限制了临床应用。近红外二区发射的聚集诱导发光材料可以极大的解决组织穿透深度等问题,促进了其在临床应用的可行性。本文从分子的构建出发总结了D-π-A和D-A-D结构的近红外二区聚集诱导发光分子在光动力-光热双模式协同治疗方面的应用。

Discovery of eclogite inclusions and its geological significance in early Jurassic intrusive complex in Xuzhou-northern Anhui, eastern China

The early Jurassic intrusive complex is chiefly made of monzodioritic porphyry in northern Anhui and northern Jiangsu, which emplaced in 191 Ma. The intrusive complexes contain a lot of eclogite inclusions which belong to eclogite and garnet-pyroxenite. The inclusions had undergone eclogite facies high-pressure metamorphism and am-phibolite facies retrogressive metamorphism. The garnets in eclogite inclusions are mainly almandine varieties and clino-pyroxenes are omphacite and augite. The mineral assemblage and P-T estimation results show that P-T conditions of eclogite facies metamorphism and amphibolite facies retrogressive metamorphism are over 1.2-1.5 GPa, 709-861°C and 0.7-1.03 GPa, 666-738°C, respectively. The discovery of the high-pressure xenoliths not only is of important significance to understand the composition and structure of deep crust in southern edge of North China Platform, but also can be of important influence on realizing the subduc-tion-collision-exhumation evolutional process

急诊和择期股疝临床特点及其修补后早期临床效果的回顾性队列研究

目的比较急诊和择期股疝的临床特点及修补术后早期临床效果。方法回顾性分析2013年1月至2018年12月,赣州市人民医院手术治疗的股疝患者的临床资料,其中择期股疝组53例,急诊股疝组85例。结果2组病例均以女性偏多,急诊组较择期组的病程偏长,年龄偏高;急诊组中有并存病的患者较多,以慢性阻塞性肺疾病、肝硬化多见。急诊组和择期组中肠梗阻患者分别为64例和4例,2组术中需肠切除、肠吻合的患者分别为14例和0例,但2组的修补方式差异无统计学意义。术后血清肿和浅表感染急诊组较择期组明显偏多,差异有统计学意义(P<0.05)。术后1个月内急诊组死亡7例,而择期组无死亡病例,K-M曲线分析Log-rank检验,差异有统计学意义(P<0.05)。结论急诊股疝合并症较择期股疝多,病程长,术后并发症多,且术后1个月内死亡率高。所以股疝一旦确诊,应及时纠正患者的并存病,尽早手术,或许可以改善股疝患者的预后。

Creep deformation and strength evolution mechanisms of a Ti-6Al-4V alloy during stress relaxation at elevated temperatures from elastic to plastic loading

In this study, the stress relaxation(SR) behaviors of a Ti-6Al-4V alloy pre-loaded from elastic to plastic regions and corresponding strength evolution mechanisms at different temperatures were systematically studied. In order to quantitatively analyze the detailed deformation and strength evolution mechanisms during the whole SR tests, which is composed of the loading stage and subsequent SR stage, the evolutions of α/β structures and dislocations have been identified by a series of microstructural observations,i.e., scanning electron microscopy(SEM), electron backscatter diffraction(EBSD), high resolution transmission electron microscopy(HRTEM), energy dispersive spectroscopy(EDS). A great quantity of entangled dislocations in α phase introduced by the plastic loading at temperatures below 800 °C promotes the emergence of SR behavior with a higher creep rate, leading to the much higher SR level with larger pre-load levels. Diffusion is significantly enhanced by dislocations accumulated at interfaces with higher temperatures(> 800 ℃), contributing to a similar SR phenomenon under different initial strain levels.Apparent strength loss has been observed after SR with high temperatures or pre-loaded to the plastic region, e.g., 94 MPa loss for 800 °C, pre-loaded with a stain of 10% and SR for 2400 s. The strength loss mainly comes from the loading stage where distorted and fragmented β layers occur. The subsequent SR stage facilitates interfacial diffusion and results in a higher fraction of granular β phases, leading to a further decrease in yield strength(YS). This study enhances the understanding on the deformation and strength evolution mechanisms of titanium alloys with lamellar structures in the whole SR process, providing a physical foundation for optimizing the processing parameters for manufacturing titanium alloy components with high accuracy and performance.

On the p-Laplacian Lichnerowicz equation on compact Riemannian manifolds

In this paper,we deal with a singular quasilinear critical elliptic equation of Lichnerowicz type involving the p-Laplacian operator.With the help of the subcritical approach from the variational method,we obtain the non-existence,existence,and multiplicity results under some given assumptions.

Abnormal chemical composition fluctuations in multi-principal-element alloys induced by simple cyclic deformation

High entropy alloys exhibit excellent combination of mechanical properties because of the unique com-position fluctuations,termed as‘concentration wave’.The concentration wave was closely related to mul-tiple aspects,including the fluctuation of local strain energy,local atomic environment,electronegativity,etc.Here we report for the first time that the amplitude of the concentration wave can be mechani-cally tailored under cyclic deformation in a well-known Cantor alloy.Atomic-scale energy-dispersive X-ray spectroscopy(EDS)mapping reveals that cyclic deformation may dynamically induce the clustering of solute atoms with a size of 1-3 nm,thus resulting in a higher concentration wave amplitude.The con-centration wave promotes strong interactions between dislocations and local solute clusters.Aside from the typical Taylor strengthening contribution due to the presence of isolated dislocations,the strength enhancement from the mechanically induced composition fluctuations was quantified to be as high as∼70 MPa,about one-third of the yield strength of the alloy without pre-deformation.This opens up a novel strategy of designing high strength alloys by tailoring solute configurations.