Assessment of electrostatic discharge sensitivity of nitrogen-rich heterocyclic energetic compounds and their salts as high energy-density dangerous compounds:A study of structural variables

Nitrogen-rich heterocyclic energetic compounds(NRHECs)and their salts have witnessed widespread synthesis in recent years.The substantial energy-density content within these compounds can lead to potentially dangerous explosive reactions when subjected to external stimuli such as electrical discharge.Therefore,developing a reliable model for predicting their electrostatic discharge sensitivity(ESD)becomes imperative.This study proposes a novel and straightforward model based on the presence of specific groups(-NH_(2) or-NH-,-N=N^(+)-O^(-)and-NNO_(2),-ONO_(2) or-NO_(2))under certain conditions to assess the ESD of NRHECs and their salts,employing interpretable structural parameters.Utilizing a comprehensive dataset comprising 54 ESD measurements of NRHECs and their salts,divided into 49/5 training/test sets,the model achieves promising results.The Root Mean Square Error(RMSE),Mean Absolute Error(MAE),and Maximum Error for the training set are reported as 0.16 J,0.12 J,and 0.5 J,respectively.Notably,the ratios RMSE(training)/RMSE(test),MAE(training)/MAE(test),and Max Error(training)/Max Error(test)are all greater than 1.0,indicating the robust predictive capabilities of the model.The presented model demonstrates its efficacy in providing a reliable assessment of ESD for the targeted NRHECs and their salts,without the need for intricate computer codes or expert involvement.

A Into-Plane Rotating Micromirror Actuated by a Hybrid Electrostatic Driving Structure

A novel into-plane rotating rnicromirror actuated by a hybrid electrostatic driving structure is presented. The hybrid driving structure is made up of a planar plate drive and a vertical comb drive. The device is fabricated in SOI substrate by using a bulk-and-surface mixed silicon micromachining process. As demonstrated by experiment, the novel driving structure can actuate the mirror to achieve large-range continuous rotation as well as spontaneous 90°rotation induced by the pull-in effect. The continuous rotating range of the micromirror is increased to about 46° at an increased yielding voltage. The measured yielding voltages of the mirrors with torsional springs of 1 and 0.5μm in thickness are 390 - 410V and 140 - 160V, respectively. The optical insertion loss has also been measured to be --1.98dB when the mirror serves as an optical switch.

Formation of Nonlinear Solitary Vortical Structures by Coupled Electrostatic Drift and Ion-Acoustic Waves

Propagation of coupled electrostatic drift and ion-acoustic waves（DIAWs） is presented. It is shown that nonlinear solitary vortical structures can be formed by low-frequency coupled electrostatic DIAWs. Primary waves of distinct（small, intermediate and large） scales are considered. Appropriate set of 3 D equations consisting of the generalized Hasegawa-Mima equation for the electrostatic potential（involving both vector and scalar nonlinearities） and the equation of motion of ions parallel to magnetic field are obtained. According to experiments of laboratory plasma mainly focused to large scale DIAWs, the possibility of self-organization of DIAWs into the nonlinear solitary vortical structures is shown analytically. Peculiarities of scalar nonlinearities in the formation of solitary vortical structures are widely discussed.

Integration of Multiple Heterointerfaces in a Hierarchical 0D@2D@1D Structure for Lightweight,Flexible,and Hydrophobic Multifunctional Electromagnetic Protective Fabrics

The development of wearable multifunctional electromagnetic protective fabrics with multifunctional,low cost,and high efficiency remains a challenge.Here,inspired by the unique flower branch shape of“Thunberg’s meadowsweet”in nature,a nanofibrous composite membrane with hierarchical structure was constructed.Integrating sophisticated 0D@2D@1D hierarchical structures with multiple heterointerfaces can fully unleash the multifunctional application potential of composite membrane.The targeted induction method was used to precisely regulate the formation site and morphology of the metal–organic framework precursor,and intelligently integrate multiple heterostructures to enhance dielectric polarization,which improves the impedance matching and loss mechanisms of the electromagnetic wave absorbing materials.Due to the synergistic enhancement of electrospinning-derived carbon nanofiber“stems”,MOF-derived carbon nanosheet“petals”and transition metal selenide nano-particle“stamens”,the CoxSey/NiSe@CNSs@CNFs(CNCC)composite membrane obtains a minimum reflection loss value(RL_(min))of-68.40 dB at 2.6 mm and a maximum effective absorption bandwidth(EAB)of 8.88 GHz at a thin thickness of 2.0 mm with a filling amount of only 5 wt%.In addition,the multi-component and hierarchical heterostructure endow the fibrous membrane with excellent flexibility,water resistance,thermal management,and other multifunctional properties.This work provides unique perspectives for the precise design and rational application of multifunctional fabrics.

Effects of anions on the structural regulation of Zn‑salen‑modified metal‑organic cage

By virtue of a 3∶1 complementary coordination strategy,a chiral heteroleptic metal-organic cage that con-tains divergent functional units,Pd‑R(Zn),was precisely constructed via self-assembly of monodentate variational Zn-salen ligands RZn and NADH(reduced nicotinamide adenine dinucleotide)mimic modified tridentate ligands with square-planar Pd ions.UV-Vis and luminescence spectra experiments reveal that different anions could selec-tively interact with different sites of Zn-salen modified metal-organic cages to achieve the structural regulation of cage compound,by using the differentiated host-guest electrostatic interactions of counter ions with metal-organic hosts.Compared to other anions,the presence of chloride ions caused the most significant fluorescence emission enhancement of Pd‑R(Zn),meanwhile,the UV-Vis absorption band attributed to the salen aromatic backbone showed an absorption decrease,and the metal-to-ligand induced peak displayed a blue shift effect.Circular dichro-ism and ^(1)H NMR spectra further demonstrate that the introduction of chloride anions is beneficial to keeping a more rigid scaffold.

(E)-1-[4-(2-hydroxy-5-methoxybenzylideneamino)-phenyl]ethanone and (E)-1-[4-(2-hydroxy-4-methoxybenzylideneamino) phenyl]ethanone:X-ray and DFT-calculated structures

The isomeric structures of（E）-1-[4-（2-hydroxy-5-methoxybenzylideneamino）-phenyl] ethanone（I） and（E）-1-[4-（2-hydroxy-4-methoxybenzylideneamino） phenyl]ethanone（Ⅱ） ,both C16H15NO3,have been determined using X-ray diffraction techniques and characterized by IR,and their molecular structures have also been optimized at the B3LYP/6-31G（d,p） level using density functional theory（DFT） . The energetic behaviors of the title compounds in solvent media have been examined using B3LYP method with the 6-31G（d,p） basis set by applying the polarizable continuum model（PCM） . The total energies of the title compounds decrease with the increasing polarity of the solvent. In addition,DFT calculations of the title compounds＇ molecular electrostatic potentials（MEP） were performed at the B3LYP/6-31G（d,p） level of theory. X-ray study shows that the title compounds both have strong intramolecular O-H…N hydrogen bonds. The molecules of Ⅰ are linked into a one-dimensional framework structure by C-H…π interactions,while in Ⅱ,intermolecular π···π interactions result in the formation of infinite chains running along the [010].

Quantitative Structure-chromatographic Retention Relationship for Polychlorinated Dibenzothiophenes and Their Corresponding Sulfones

Polychlorinated dibenzothiophenes（PCDTs）and their corresponding sulfone（PCDTO2）compounds are a group of important persistent organic pollutants.In the present study,geometrical optimization and subsequent calculations of electrostatic potentials（ESPs）on molecular surface have been performed for all 135 PCDTs and 135 PCDTO2 congeners at the HF/6-31G*level of theory.A number of statistically-based parameters have been extracted.Linear relationship between gas-chromatographic retention index（RI）and the structural descriptors have been established by multiple linear regression.The result shows that two descriptors derived from positive electrostatic potential on molecular surface, ■ and π,together with the molecular volume(Vmc)and the energy of the lowest unoccupied molecular orbital(ELUMO)can be well used to express the quantitative structure-retention relationship（QSRR）of PCDTs and PCDTO2.Predictive capability of the two models has been demonstrated by leave-one-out cross-validation with the cross-validated correlation coefficient(RCV)of 0.996 and 0.997,respectively.Furthermore,the predictive power of the models is further examined for the external test set.Correlation coefficients（R）between the observed and predicted RI values for the external test set are 0.997 and0.998,respectively,validating the robustness and good prediction of our model.The QSRR model established may provide again a powerful method for predicting chromatographic properties of aromatic organosulfur compounds.

旋转结构摩擦纳米发电机的材料、结构及应用研究进展

综述了近年来旋转结构摩擦纳米发电机(R-TENG)在能量收集和传感领域的研究进展,介绍了不同结构R-TENG的基本工作原理、性能调控以及应用。详细分析了导电刷式结构、接触-分离式结构、独立层式结构以及恒流式结构的R-TENG,总结了各种结构R-TENG将振动、旋转、波浪、风和热源等能量高效转化为电能的方法和规律,比较了它们各自的结构设计、外部激励和电力输出。重点介绍了独立层结构中较为关键的减磨结构、悬浮结构以及模式切换。研究表明R-TENG具有将环境中的机械能转化为电能的应用潜力。最后,指出了R-TENG未能进行产业化的主要原因,同时展望了R-TENG在自供能传感、分布式能源等领域的未来发展方向。

外加电场下电介质颗粒层结构重构与悬浮

施加电场控制荷电颗粒的运动广泛应用于工业过程。目前对电介质颗粒群在电场中行为的研究仍不充分。因此,通过数值模拟研究了电介质颗粒层在外加电场内的完整动力学行为。基于研究结果,首先构建了电场中电介质颗粒的行为模式相图,并推导出相邻区域的边界。进一步表征了颗粒层结构,探究了外场和颗粒间静电作用对结构重构的影响机制。最后,对颗粒层的悬浮运动过程进行了分析。

内嵌NPN结构的高维持电压可控硅器件

针对传统可控硅(SCR)器件触发电压高、维持电压低、闩锁风险大等问题,提出了一种内嵌NPN结构的高维持电压SCR器件。维持电压由传统器件的1.2 V增大到10.3 V。与传统结构相比,该新型SCR结构体内存在2条电流路径,通过嵌入的NPN电流路径延缓了器件中寄生PNP管的开启过程,抑制了SCR结构里NPN管与PNP管的正反馈过程,使得SCR电流路径在电流较大时才能完全开启,从而达到提高维持电压的目的。基于半导体器件仿真软件,模拟了器件在直流下的电学特性,分析其工作机理并讨论了关键器件参数对其电学特性的影响。

高压静电场解冻对凡纳滨对虾肌球蛋白结构特征的影响

该研究以去头凡纳滨对虾为材料,以羰基与总巯基含量、表面疏水性与粒径大小、内源荧光光谱与傅里叶变换红外光谱和聚丙烯酰胺凝胶电泳的特征等作为考察指标,以自然解冻(nature thawing,NT)作为对照,研究了高压静电场解冻(high voltage electrostatic field thawing,HVEFT)的场强(1.8、3.8、4.3 kV)和温度(5、15、25℃)对去头虾肌球蛋白结构的影响。结果表明,当场强为3.8 kV时,随着温度的升高,总巯基、粒径、α-螺旋的含量呈先增后减的趋势,表面疏水性呈先下降后上升的趋势,羰基和内源荧光强度逐渐增加。当温度在15℃时,随着场强的增加,总巯基、α-螺旋表现为先增后减的趋势,羰基逐渐增加,表面疏水性则呈现出先下降后上升的趋势。综上所述,当场强为3.8 kV,温度为15℃时,高压静电场解冻对去头肌球蛋白结构影响最小。在此条件下,与NT处理组相比,HVEFT处理组样品的总巯基(3.35 mol/104g)和α-螺旋的占比(30.7%)分别是NT的1.15倍和1.17倍,表面疏水性是NT(22.54μg/mL)的0.42倍。结果表明,HVEFT能较好地维持虾肌球蛋白结构稳定性,有利于去头虾解冻后品质的保持。研究结果为高压静电场技术在水产制品解冻中的应用提供科学依据。

清瘟护肺颗粒化学成分研究

目的研究清瘟护肺颗粒的化学成分。方法查阅中国知网、PubMed、Web of Science等数据库,检索该制剂组方药材化学成分的相关文献,结合文献报道和ChemicalBook数据库信息,建立化学成分数据库。采用超高效液相色谱-四极杆/静电场轨道阱高分辨质谱(UHPLC-Q Exactive Focus MS/MS)法分析制剂的图谱数据,并以Xcalibur 4.0软件拟合分子式,与自建数据库信息进行匹配,初步推测分子式信息,与ChemicalBook或ChemSpider数据库比对,推测化学成分结构。结果共鉴定出158个化学成分,包括苷类36个,黄酮类29个,苯丙素类28个,有机酸类18个,萜类17个,色原酮类8个,其他类22个。结论所建立的方法可系统、准确、快速地定性分析清瘟护肺颗粒中的化学成分。

静电除尘器本体型式综述及双层电除尘研究

静电除尘器是工业烟气粉尘治理的主流设备,小型高效化是全球节能降碳背景下静电除尘器的发展趋势。本研究对国内外典型静电除尘器型式进行了分析,对不同型式的壳体、阴阳极等关键构件布置形式进行了对比,在此基础上设计了双层静电除尘型式,配置了关通道技术以控制二次扬尘;对浙江宁波某1000MW机组配套采用上述不同类型静电除尘器进行了技术经济性对比分析,结果表明,在相同的比集尘面积下,双层静电除尘器用钢量可降低12%以上,设备产生的碳排放量降低720吨,同时降低了电除尘器的运行电耗,具有明显的技术经济性。

静电成形薄膜反射面天线的裁剪设计

该文通过裁剪和拼接平面薄膜片来对静电成形薄膜反射面天线的表面进行设计制作。由于抛物面型薄膜反射面是一个不可展开表面,通常由许多平面薄膜片制作而成,将不可避免地降低反射面表面的精度。因此,需要详细地分析裁剪和拼接过程对反射面表面精度的影响,从而获得设计需要的表面精度。该文基于旋转抛物面的无矩理论建立了工作状态的反射面模型,采用常应变三角形单元离散反射面,建立了反射面的展平和拼接有限元模型。将同口径反射面沿经线划分若干组不同数量子曲面,通过子曲面进行展平和拼接数值仿真分析,对薄膜反射面进行裁剪设计。最后,制作了0.55 m口径的薄膜反射器,并进行了摄影测量实验。验证了该方法的有效性,并讨论了制造误差的影响。

Mechanistic Insights into Structural Stability of the Selectivity Filters in Typical Cation Channels

The reliable functioning of ion channels should be closely related to their structural stability. The selectivity filter in the KcsA potassium channel possesses four stable ion binding sites that can coordinate nearly fully dehydrated ions, whereas only two of such binding sites exist in the non-selective NaK channel, and none of them is found in the NavAb sodium channel. Here we show that the stability of the selectivity filters in these tetrameric cation channels is inversely correlated with the number of stable binding sites by extensive molecular dynamics simulations. While the presence of coordinated ions is crucial for the selectivity filters of the KcsA and NaK channels to stabilize the conformations in their crystal structures, the selectivity filter of the NavAb channel shows higher stability, independent of the presence of ions. We further show that the distinct repulsive electrostatic interactions between negatively charged oxygen atoms in the selectivity filter which form the stable binding sites are responsible for the different stability of these cation channels. The hydrogen bonding networks between residues in the selectivity filter and its adjacent pore helix also play an important role in maintaining stability. Together, these results provide important mechanistic insights into the structural stability of the selectivity filters in typical cation channels.

A theoretical model of electrostatic ultrasonic transducers with micro air-gap structure

A new plate-on-air-spring model (or called short tube or DK model) for modelling the behaviour of electrostatic air-coupled ultrasonic transducers is developed and verified by accurate predictions of natural frequencies of a typical transducer with V-grooved backplate.

一体化高压触发器绝缘隔板结构优化研究

一体化高压触发器作为高功率准分子激光器系统的同步控制器件,为激光放大器的气体火花开关提供触发脉冲。提高触发器的输出电压有助于改善激光放大器的同步性能,还需解决充电过程中的自放电问题。为此,在高压腔体内部加入绝缘隔板提升腔体内的直流充电电压。基于静电场仿真和放电等离子体仿真优化设计绝缘隔板的尺寸和位置参数,通过实验对仿真结果进行验证。使用静电场仿真分析触发器腔体内放电气体区域,建立与该放电区真实模型等效的缩比模型,通过放电等离子体仿真模拟带有不同尺寸和位置隔板气体间隙的击穿电压,选出击穿电压最高时所对应的隔板尺寸和隔板位置作为隔板的优化设计方案。与无隔板的情况相比,优化后的气体间隙的平均击穿电压由58.42 kV提升到84.33 kV,实验结果和仿真计算结果较为一致。本文的优化方案提高了直流击穿电压,解决了触发器充电时的自放问题,为绝缘结构优化提供一种新方法。

静电纺聚乳酸纳米纤维的制备及其孔结构调控

为了调控聚乳酸(PLA)纳米纤维的孔结构,采用静电纺丝技术,以PLA母粒为原料,三氯甲烷(CF)和N,N-二甲基甲酰胺(DMF)按一定比例混合的溶液为溶剂,制备了平均直径在1.37μm的PLA纳米纤维,并对其结构进行表征。结果表明,PLA纳米纤维的平均直径随着纺丝液中CF含量、聚合物浓度、环境湿度的增加而增大;随纺丝电压和灌注速度的增大而呈减小的趋势。同时,环境湿度对纤维表面孔结构有显著影响。随着湿度的增加,纤维表面孔的分布密度增加,且形状由圆形转变为椭圆形。此外,与表面光滑的PLA纳米纤维(2.4 m^(2)/g)相比,所制备的PLA多孔纤维的比表面积提升了10倍(24.0 m^(2)/g)。

层级孔喷涂粉末构筑及新一代长寿命热障涂层材料的研究进展

广泛应用于航空发动机和地面燃气轮机中的热障涂层具有低热导率和良好的耐温性能,能够降低涡轮叶片表面温度,使高温结构件能在高于其熔点的环境中长时间高效率的服役。热障涂层的性能和寿命受到陶瓷层材料与其结构的直接影响,采用可控原料粉末对陶瓷涂层进行微观结构调节的方法可以减少涂层中的应变-应力失配,具有操作灵活、效果显著、调控范围广等优势。针对传统热障涂层应变容限低,抗热震性能不足等问题,本团队开发了静电喷雾技术结合相分离原理(ESP)制备新型热喷涂微球粉末的造粒理论和实现方法,实现了对粉末形貌结构的精确构筑,可用于制备核壳、均质和层级孔等全体系喷涂微球粉末。与传统的喷涂粉末相比,其中层级孔微球粉末(由特殊的纳米-微米层级跨尺度孔构成)呈现耐烧结、低热导率、高比强度及95%以上的高温波段反射率特点。使用层级孔微球粉末喷涂的热障涂层由于层级孔特征结构的保留,展现出优异的力学性能和隔热性能,热循环寿命提升2倍以上,热导率下降50%以上,且在服役过程中体现出良好的抗烧结性能。ESP造粒技术为新型热障涂层材料从材料设计到工程应用提供了一种快速的涂层性能调控方法,现已成功应用于稀土锆酸盐、稀土钽酸盐和稀土掺杂YSZ高熵体系等新型热障涂层的制备之中,随着层级孔结构对材料力学、光学、热学的深入研究及其内部拓扑结构的精确控制,未来将会在航空航天、军事国防、荧光测温等领域获得更为广泛的应用。

大型货车外壳静电粉末涂装工艺研究

粉末喷涂具有环境友好、生产效率高、涂层机械性能好等突出优势,是大型车辆涂装的发展趋势。大型货车外壳具有大表面积和异形结构的特征,其异形特征与喷涂工艺之间可以产生相互影响的耦合效应,直接影响涂层厚度的均匀性,如何保证均匀的涂层厚度是提高涂装制品质量的关键。为了更合理的指导粉末涂装工艺设置,本研究综合考察了喷涂电压、喷涂时间以及工件曲率半径对工件涂层厚度的影响。结果显示,在一定范围内提高喷涂电压和喷涂时间,可以提高涂层厚度,但是过高的喷涂电压和喷涂时间,粉末与工件之间会发生击穿,并减小涂层厚度;提高喷涂电压,到达最大涂层厚度的时间缩短;工件曲率半径越小,表面电荷密度越高。达到最大涂层厚度的喷涂电压和喷涂时间越小。在实际生产中,必须综合考虑喷涂电压、喷涂时间以及工件曲率三个因素对涂层厚度的影响。本研究成果将为精确优化粉末喷涂生产工艺提供理论依据。