西部高校化学(师范)专业建设虚拟教研室——基本情况和建设思考

“西部高校化学(师范)专业建设虚拟教研室”由西部地区6所师范大学共同申报,2022年2月15日获得教育部批准。本文简要介绍该虚拟教研室基本情况、建设内容和建设的背后思考。

Simulations of Coarsening Behavior for M_(23)C_6 Carbides in AISI H13 Steel

Based on the local equilibrium assumption, coarsening behavior of M23C6 carbide at 700℃ in H13 steel was simulated by DICTRA software. The results from the calculations were compared with transmission electron microscopy （TEM） observations. The results show the interracial energy for M23C6 in H13 steel at 700℃ is thus probably 0.7J·m^-2, which fits the experiments well. The influence of composition and temperature on the coarsening rate was also investigated by simulations. Simulations show a decrease in the coarsening rate when V/Mo ratio is increased, while the coarsening rate increases with increasing temperature.

有表面机械磨损处理辅助的合金钢强化渗硼动力学

用表面机械磨损处理(SMAT)在AISI H13钢上制备一层纳米结构的表面层。研究了这种SMAT试样的渗硼性能和粗晶粒对应物的比较。SMAT试样的硼扩散深度在600℃,2 h渗硼后的峰值是8μm,比粗晶粒试样深得多。在SMAT试样上用600℃接着更高温度的双重渗硼处理能合成厚得多的渗硼层。而且SMAT试样的活化能是1403 kJ/mol,比粗晶粒的209.4 kJ/mol低得多。结果表明,用双重渗硼处理的SMAT试样能明显增强渗硼动力学。而且热疲劳试验表明,具有优良抗氧化性和高温机械强度的渗硼层能有效延迟热疲劳裂纹的萌生,阻碍它们的传播。所以经双重渗硼处理的H13钢的热疲劳性能可以大大提升。

Influence of Cryogenic Treatment on Microstructure and Properties Improvement of Die Steel

Cryogenic treatment has been increasingly applied to enhance the hardness, antiwear ability and fatigue performance of die steel. On the basis of reading a large number of research papers and references across the world, the author makes a detailed analysis and brief summary of the influence of cryogenic treatment on microstructure after quenching process or quenching plus tempering process, on first and second carbides, on content of retained austenite, on surface hardness, on mechanical properties and antiwear ability of die steels. It’s proved that cryogenic treatment on die steel significantly improves its hardness, antiwear capacity and service life. It’s the cryogenic process to make die steel have higher hardness, better antiwear ability, better ductility and longer service life because cryogenic process actually has a good influence on die steel of its microstructure, retained austenite volume and amount and size of the second carbide.

Plasmonic nanostructures acting as a light-driven O_(2)-sensitive nitroreductase mimic for enhanced photochemical oxidation of para-aminothiophenol

Nanozymes,as a novel form of enzyme mimics,have garnered considerable interest.Despite overcoming the main disadvantages of their natural analogs,they still face challenges such as restricted mimic types and low substrate specificity.Herein,we introduce a reactive ligand modification strategy to diversify enzyme mimic types.Specifically,we have utilized helical plasmonic nanorods(HPNRs)modified with para-nitrothiophenol(4-NTP)to create an oxygen-sensitive nitroreductase(NTR)with light-controllability.HPNRs act as a light-adjustable source of nicotinamide adenine dinucleotide/nicotinamide adenine dinucleotide phosphate(NAD(P)H),providing photon-generated energetic electrons to adsorbed 4-NTP molecules.In the presence of O_(2),the activated 4-NTP transfers the captured electron to the adsorbed O_(2),mimicking the electron transfer process in its natural counterpart.This enhanced O_(2)activation notably boosts the oxidative coupling of para-aminothiophenol(4-ATP).Density functional theory(DFT)calculations reveal that hot electrons injected into the lowest unoccupied molecular orbital(LUMO)energy level of 4-NTP can be transferred to that of molecular oxygen.In conclusion,our findings underline the potential of the reactive ligand modification strategy in developing new types of enzyme reactions,which opens up promising avenues for the enhancement and diversification of nanozyme functionalities.

Temperature-modulated inversion and switching of chiroptical responses in dynamic side-by-side oligomers of gold nanorods

Herein,a new strategy is proposed for achieving dynamic chiral controls in self-assembly systems of plasmonic nanorods based on temperature-modulation.Via enlarging Au{100}side facets of Au nanorod(AuNR)building block and changing surface ligand from often-used cetyltrimethylammonium bromide(CTAB)to cetylpyridinium chloride(CPC),inversion of chiroptical signal in side-by-side(SS)oligomers is realized.Under the guide of chiral cysteine(Cys),Au{100}side facet-linked SS rods twist in the opposite direction compared with Au{110}side facet-linked counterparts.At high CPC concentration,by controlling the incubation temperature of chiral Cys,the dominant twist mode can be regulated.Finite-difference time-domain(FDTD)simulations indicate the key role of the twisting dihedral angle of the oligomers in driving chiral signal inversion.At low CPC concentration,a temperature-sensitive chiral switching is observed owing to the conformation change of the CPC ligand layer.The temperature-modulated chiral responses are based on the interactions of chiral molecules,achiral surface ligands,and exposed facets of the building block.The rich dynamic tunability of chiroptical responses of plasmonic assemblies may find applications in stimulus-responsive nanodevices.

Study on risk assessment and factors ranking of the LTE-M communication system

To assess the operational safety risk of long-term evolution for the metro(LTE-M)communication system more accurately,the guide maintenance strategy,the improved evidence theory and the multi-attribute ideal reality comparative analysis(MAIRCA)approaches are proposed.According to the features of LTE-M system,the risk evaluation system is established.The enhanced structural entropy weight method is used to obtain the weight.Furthermore,it is combined with nine-element fuzzy mathematics to transform the degree of membership,modifying the conflict and fusion rules to solve the confidence degree clashed problem of evidence theory.Then,the system risk grade assessment result is obtained.For the purpose of forming the ranking of indicator importance,the MAIRCA is introduced and the ranking is three-dimensional.The operational state of the metro line is used as the data source in various ways the obtained risk grade increased by 7.12%.It is verified that MAIRCA can be applied to the field of urban rail transit because it has based on the test and calculation.The results show that the method is effective;compared with others,the confidence degree of excellent stability and the ranking result of risk factors is reasonable.The influencing indicator with the highest importance is the'equipment failure rate".

Research on text fault recognition for on-board equipment of a C3 train control system based on an integrated XGBoost algorithm

The robust guarantee of train control on-board equipment is inextricably linked to the safe functioning of a high-speed train.A fault diagnostic model of on-board equipment is built utilizing the integrated learning XGBoost(eXtreme Gradient Boosting)algorithm to help technicians assess the malfunction category of high-speed train control on-board equipment accurately and rapidly.The XGBoost algorithm iterates multiple decision tree models to improve the accuracy of fault diagnosis by lifting the predicted residual and adding regular terms.To begin,the text features were extracted using the improved TF-IDF(Term Frequency-Inverse Document Frequency)approach,and 24 fault feature words were chosen and converted into weight word vectors.Secondly,considering the imbalanced fault categories in the data set,the ADASYN(Adaptive Synthetic sampling)adaptive synthetically oversampling technique was used to synthesize a few category fault samples.Finally,the data samples were split into training and test sets based on the fault text data of CTCS-3train control on-board equipment recorded by Guangzhou Railway Group maintenance personnel.The XGBoost model was utilized to realize the automatic fault location of the test set after optimized parameter tuning through grid search.Compared with other methods,the evaluation index of the XGBoost model was significantly improved.The diagnostic accuracy reached 95.43%,which verifies the effectiveness of the method in text fault diagnosis.

Fault diagnosis of railway point machines based on wavelet transform and artificial immune algorithm

Aiming at the current problems of high failure rate and low diagnostic efficiency of railway point machines(RPMs)in the railway industry,a short-time method of fault diagnosis is proposed.Considering the effect of noise on power signals in the data acquisition process of the railway centralized signaling monitoring(CSM)system,this study utilizes wavelet threshold denoising to eliminate interference.The results show that the accuracy of fault diagnosis can be improved by 4.4% after denoising the power signals.Then in order to attain a lighter weight and shorten the running time of the diagnosis model,Mallat wavelet decomposition and artificial immune algorithm are applied to RPM fault diagnosis.Finally,voluminous experiments using veritable power signals collected from CSM are introduced,which show that combining these methods can procure higher precision of RPMs and curtail fault diagnosis time.This substantiates the validity and feasibility of the presented approach.

Gold nanorods core/AgPt alloy nanodots shell： A novel potent antibacterial nanostructure

根据银 nanoparticles (Ag NP ) 的当前的问题以抗菌剂性能，我们与取向附生地作为一个潜在的抗菌剂代理人在金 nanorods (Au@PtAg NR ) 上种的 AgPt 合金 nanodots 设计了新奇 trimetallic 核心 / 壳 nanostructure。两 Escherichia coli (E。coli ) 并且葡萄球菌 aureus (S。aureus ) 被学习。抗菌剂活动展出明显的作文依赖。在在合金壳增加 Ag 部分直到 80% 以后，抗菌剂活动逐渐地增加，表明一个灵活方法调节这项活动。在 80% Ag，抗菌剂活动比纯 Ag 壳的好。改进抗菌剂能力主要由于点形态学在壳表面上源于银的高暴露。当为基于 Ag 的 nanomaterials 保留高化学的稳定性时，我们因此证明形成合金是改进抗菌剂活动的一个有效方法。而且，由于悦耳的局部性的表面 plasmonic 反应在在红外线附近(NIR ) 光谱区域，对把 lightsuch 用作杀死的 photothermal 和 phototriggered 银离子 releaseis 的抗菌剂活动的另外的控制期望。作为示范，高度提高了抗菌剂活动被利用 nanostructures 的 NIR photothermal 效果显示出。我们的结果显示如此的定制的 nanostructures 将在对细菌的未来战斗发现一个角色，包括 multidrug 抵抗的增加的严厉的挑战。

Temperature dependent Raman and photoluminescence of vertical WS2/MoS2 monolayer heterostructures

Heterostructures from two-dimensional transition-metal dichalcogenides MX_2 have emerged as a hot topic in recent years due to their various fascinating properties. Here, we investigated the temperature dependent Raman and photoluminescence(PL) spectra in vertical stacked WS_2/MoS_2 monolayer heterostructures. Our result shows that both E_(2g)~1 and A_(1g) modes of WS_2 and MoS_2 vary linearly with temperature increasing from 300 to 642 K. The PL measurement also reveals strong temperature dependencies of the PL intensity and peak position. The activation energy of the thermal quenching of the PL emission has been found to be equal to 69.6 meV. The temperature dependence of the peak energy well follows the bandgap shrinkage of bulk semiconductor.

An in vivo study of the biodistribution of gold nanoparticles after intervaginal space injection in the tarsal tunnel

The biodistribution of gold nanoparticles （AuNPs） is closely related to toxicological effects and is of great concern because of their potential application in diverse biomedical areas. However, with the discovery of novel anatomic and histological structures for fluid transport, the underlying mechanisms involved in the in vivo transport and biodistribution of AuNPs require further in-depth investigations. In the current study, we investigated the biodistribution of 10-nm AuNPs in rats after intervaginal space injection （ISI） in the tarsal tunnel, where a focal point of tendons, vessels, and nerve fibers may optimally connect to other remote connective tissues. The intravenous injection （IVI） of AuNPs served as a control. The blood and organs were collected at 5, 15, and 30 min and at 1, 4, 12, and 24 h after injection for quantitative analysis of Au distribution with inductively coupled plasma mass spectrometry （ICP-MS）. IVI and ISI yielded significantly different results： The AuNP content in the blood after ISI was much lower than that after IVI; was similar in the lungs, heart, and intestines; and was higher in the skin and muscle. These findings were supported by the ratios of AuNP content and relative organ AuNP distribution proportions. Our results demonstrated a fast, direct, and the circulation-independent AuNP-organ transport pathway, which may improve our understanding of physiological and pathological biodistribution processes in biological systems. Furthermore, these results provide novel insights into the in vivo transport and biodistribution of AuNPs, which may lead to novel and efficient therapeutic and administration strategies.

Fabrication of chiral plasmonic oligomers using cysteine-modified gold nanorods as monomers

在紫外区域以外的圆形的二色性(CD ) 的产生具有对开发 chiral 传感器和 chiroptical 设备的大兴趣。此处，我们在可见、近的红外与强壮的 CD 反应为 plasmonic oligomers 的制造表明一个简单、万用的方法光谱范围。oligomers 被被触发制作一起修改半胱氨酸的金 nanorods 的汇编。修改 nanorods 自己没展出明显的 plasmonic CD 信号；然而， oligomers 表演在电浆子回声波长附近的强壮的 CD 乐队。CD 乐队的符号被吸收半胱氨酸分子的 chirality 支配。由调整 oligomers， chiral 分子的集中，或 nanorods 的方面比率的尺寸， CD 紧张并且光谱范围是容易地悦耳的。理论计算建议 oligomers 的那 CD 在 oligomer 以内从邻近的 nanorods 的细微扭曲发源。因此，我们建议吸附的 chiral 分子能操作在 nanorods 之间的扭曲角度并且因此调制 oligomers 的 CD 反应。

Probing hydroxyl radical generation from H2O2 upon plasmon excitation of gold nanorods using electron spin resonance： Molecular oxygen-mediated activation

Gold nanostructures are among the noble metal nanomaterials being intensely studied due to their good biocompatibility, tunable localized surface plasmon resonance （SPR）, and ease of modification. These properties give gold nano- structures many potential chemical and biomedical applications. Herein, we demonstrate the critical role of oxygen activation during the decomposition of hydrogen peroxide （H202） in the presence of photoexcited gold nanorods （AuNRs） by using electron spin resonance （ESR） techniques. Upon SPR excitation, 02 is activated first, and the resulting reactive intermediates further activate H202 to produce ,OH. The reactive intermediates exhibit singlet oxygen-like （102-1ike） reactivity, indicated by 102-specific oxidation reaction, quenching behaviors, and the lack of the typical 102 ESR signal. In addition, by using the antioxidant sodium ascorbate （NaA） as an example, we show that hydroxyl radicals from H202 activation can induce much stronger NaA oxidation than that in the absence of H202. These results may have significant biomedical implications. For example, as oxidative stress levels are known to influence tumorigenesis and cancer progression, the ability to control redox status inside tumor microenvironments using noble metal nanostructures may provide new strategies for regulating the metabolism of reactive oxygen species and new approaches for cancer treatment.

Minimizing the effect of near-distance dielectric sensitivity on retrieving average aspect ratio of gold nanorod by optical extinction spectroscopy:in the case of CTAB adsorption

The aspect ratio(AR)is one of the most intriguing parameters of gold nanorods(GNRs),which plays an important role in determining localized surface plasmon(LSPR)properties.Instead of conventional imaging techniques,the optical extinction spectroscopy(OES)method has been developed for allowing fast statistically measuring the average AR under static approximation.In this work,combining with the previous achievements in spectroscopic technique,we further analyze the effects of gold dielectric function and near distance dielectric sensitivity.The former may reflect possible dielectric loss of real Au samples from ideal single crystalline.The latter reflects the cetyltrimethylammonium bromide(CTAB)adsorption on the surface of GNR induces different LSPR shifts below and above critical micelle concentration(CMC).However,their effect on the determination of AR has not been evaluated in OES method.The average AR measurements as a function of absorbance of CTAB-GNRs and LSPR maximum below the CMC were studied.Our results indicate that after considering these factors,the mean ARs obtained from spectroscopic techniques are closer to those obtained from imaging techniques.

Ferroxidase-like activity of Au nanorod/Pt nanodot structures and implications for cellular oxidative stress

铂 nanoparticles (NP ) 被报导模仿各种各样的抗氧化剂酶并且可以因此由减少反应的氧生产积极生物效果种类(ROS ) 层次。在这张手稿，我们报导磅 NP 由在金 nanorods (Au@Pt NDR ) 上扔铂 nanodots ferroxidase 作为酶模仿。Au@Pt NDR 显示出 pH 依赖的象 ferroxidase 一样活动并且在中立 pH 价值举办更高的活动。有人的房间线(肺腺癌 A549 和正常支气管的上皮的房间线 HBE ) 的 Cytotoxicity 结果证明 Au@Pt NDR 经由 endocytosis 和 translocate 被收起进房间进 endosome/lysosome。Au@Pt NDR 在比 0.15 n 低的 NDR 粒子集中有好 biocompatibility。然而，面对 H 2 O 2, lysosomelocated NDR 展出象 peroxidase 一样活动因此增加 cytotoxicity。面对 Fe 2+, ， NDR 的象 ferroxidase 一样活动由消费 H 2 O 2 。当在生物系统采用 Au@Pt NDR 时，彻底的考虑应该被给这行为。

Special interstitial route can transport nanoparticles to the brain bypassing the blood-brain barrier

Nowadays,nanoparticles(NPs)are considered to be ideal tools for bioimaging and drug delivery.Although increasing research has focused on NP biodistribution,transportation in the interstitial architecture has been neglected.The entire body is connected by the interstitial architecture,which can provide a long-range and direct pathway for NP biodistribution in a nonvascular system.In this study,we report that 10-nm gold NPs injected directly into the interstitial architecture of the tarsal tunnel of rats(intervaginal space injection(ISI))were delivered to the brain without crossing the blood-brain barrier.Furthermore,NaGdF4 nanoparticles were used to explore the transportation route by magnetic resonance imaging.The results demonstrated that,after ISI,the NaGdF4 nanoparticles were transported through the perivascular interstitial space of the carotid arteries and brain vessels to the brain.This is a special nonvascular transportation route like a stream based on the interstitial architecture that provides an alternative pathway for NP biodistribution.

Rod-shaped Au@PtCu nanostructures with enhanced peroxidase-like activity and their ELISA application

Pt and its based alloy nanoparticles(NPs)have been reported to demonstrate novel enzyme-like activities.Varying composition is very important to realize the optimization of their functions through the tuning of electronic structure.In this paper,our effort is focused in this direction by tailoring the electronic structure of Pt NPs via alloying with copper.Using gold nanorod(Au NR)as core,a simple method to prepare PtCu alloy shell is developed(termed as Au@PtCu NR).The introduction of copper could result in endcap-preferred growth mode owing to the lattice mismatch between alloy shell and the Au core.The variation in the electronic structure changes the substrate affinity,and enhanced affinity was found for H2O2.Besides,the designed Au@PtCu nanostructures have realized spatial separation of catalytic and recognition sites.Binding of recognition antibodies had negligible effect on their catalytic activity.Based on their peroxidaselike activity,a highly sensitive detection of human immunoglobulin G(IgG)was demonstrated in a direct enzyme-linked immunosorbent assay(ELISA)mode.The detection limit can be as low as 90 pg/mL.

Formation of plasmon quenching dips greatly enhances ^1O2 generation in a chlorin e6-gold nanorod coupled system

Photodynamic therapy （PDT）, as a noninvasive therapeutic method, has been actively explored recently for cancer treatment. However, owing to the weak absorption in the optically transparent windows of biological tissues, most com- mercial photosensitizers （PSs） exhibit low singlet oxygen （^1O2） quantum yields when excited by light within this window. Finding the best way to boost ^1O2 production for clinical applications using light sources within this window is, thus, a great challenge. Herein, we tackle this problem using plasmon resonance energy transfer （PRET） from plasmonic nanoparticles （NPs） to PSs and demonstrate that the formation of plasmon quenching dips is an effective way to enhance ^1O2 generation. The combination of the photosensitizer chlorin e6 （Ce6） and gold nanorods （AuNR） was employed as a model system. We observed a clear quenching dip in the longitudinal surface plasmon resonance （LSPR） band of the AuNRs when the LSPR band overlaps with the Q band of Ce6 and the spacing between Ce6 and the rods is within the acting distance of PRET. Upon irradiation with 660 nm continuous-wave laser light, we obtained a seven-fold enhancement in the ^1O2 signal intensity compared with that of a non-PRET sample, as determined using the ^1O2 electron spin resonance probe 2,2,6,6-tetramethyl-4-piperidine （TEMP）. Furthermore, we demonstrated that the PRET effect is more efficient in enhancing ^1O2 yield than the often-employed local field enhancement effect. The effectiveness of PRET is further extended to the in vitro level. Considering the flexibility in manipulating the localized SPR properties of plasmonic nanoparticles/nanostructures, our findings suggest that PRET-based strategies may be a general way to overcome the deficiency of most commercial organic PSs in biological optically transparent windows and promote their applications in clinical tumor treatments.