Shock Initiation Experiments with Modeling on a DNAN Based MeltCast Insensitive Explosive

2,4-dinitroanisole(DNAN)is a good replacement for 2,4,6-trinitrotoluene(TNT)in melt-cast explosives due to its superior insensitivity.With the increasing use of DNAN-based melt-cast explosives,the prediction of reaction violence and hazard assessment of the explosives subjected to shock is of great significance.This study investigated the shock initiation characteristics for a DNAN-based melt-cast explosive,DHFA,using the one-dimensional Lagrangian apparatus.The embedded manganin gauges in the apparatus record the pressure histories at four Lagrangian positions and show that shock-todetonation transition in DHFA needs a high input shock pressure.The experimental data are analyzed to calibrate the Ignition and Growth model.The calibration is performed using an objective function based on both pressure history and the arrival time of shock.Good agreement between experimental and calculated pressure histories indicates the high accuracy of the calibrated parameters with the optimization method.

Angular insensitive nonreciprocal ultrawide band absorption in plasma-embedded photonic crystals designed with improved particle swarm optimization algorithm

Using an improved particle swarm optimization algorithm(IPSO)to drive a transfer matrix method,a nonreciprocal absorber with an ultrawide absorption bandwidth and angular insensitivity is realized in plasma-embedded photonic crystals arranged in a structure composed of periodic and quasi-periodic sequences on a normalized scale.The effective dielectric function,which determines the absorption of the plasma,is subject to the basic parameters of the plasma,causing the absorption of the proposed absorber to be easily modulated by these parameters.Compared with other quasi-periodic sequences,the Octonacci sequence is superior both in relative bandwidth and absolute bandwidth.Under further optimization using IPSO with 14 parameters set to be optimized,the absorption characteristics of the proposed structure with different numbers of layers of the smallest structure unit N are shown and discussed.IPSO is also used to address angular insensitive nonreciprocal ultrawide bandwidth absorption,and the optimized result shows excellent unidirectional absorbability and angular insensitivity of the proposed structure.The impacts of the sequence number of quasi-periodic sequence M and collision frequency of plasma1ν1 to absorption in the angle domain and frequency domain are investigated.Additionally,the impedance match theory and the interference field theory are introduced to express the findings of the algorithm.

Insensitive energetic microspheres DAAF/RDX fabricated by facile molecular self-assembly

Insensitive energetic materials are promising in the defense weapons field.However,energetic materials still suffer from great challenges and the concern about their safety limits their utilization.In this work,insensitive energetic explosive 3,30-diamino-4,40-azoxyfurazan/hexahydro-1,3,5-trinitro-1,3,5-triazine(DAAF/RDX)microspheres were fabricated by self-assembly method.Rod-like DAAF/RDX was prepared by mechanical ball milling for comparison.DAAF/RDX composites with different mass ratios(90:10,80:20,and 70:30)were obtained.The morphologies and structures of as-obtained DAAF/RDX composites were characterized by scanning electron microscopy(SEM),powder x-ray diffraction(PXRD)and fourier transform infrared spectroscopy(FT-IR).The results showed that DAAF/RDX microspheres exhibited regular shaped microspheres with sizes from 0.5 to 1.2 mm.There was no crystal transition during the modification process.The thermal properties of as-obtained materials were then evaluated by differential scanning calorimetry(DSC)and materials studio software.DAAF/RDX microspheres showed an advanced decomposition peak temperature compared with rod-like DAAF/RDX.The binding energy and peak temperature values at zeroβ_(i)(T_(P0))of DAAF/RDX(90:10)increased by 36.77 kJ/mol,1.6℃,and 58.11 kJ/mol,12.3℃compared to DAAF/RDX(80:20)and DAAF/RDX(70:30),indicating the better thermal stability of DAAF/RDX(90:10).The characteristic drop height(H_(50))of DAAF/RDX(higher than 100 cm)composites was higher than that of raw RDX(25 cm),suggesting significant improvements in mechanical safety.The preparation of DAAF/RDX microspheres is promising for the desensitization of RDX and useful for the formation of other materials and future wide applications.

Insensitive high explosives:Ⅳ. Nitroguanidine-Initiation & detonation

This paper reviews the detonative properties of low bulk density(LBD),high bulk density(HBD)Nitroguanidine(NGu)(1),CAS-No:[556-88-7]and 82 explosive formulations based on NGu reported in the public domain.To rank the performance of those formulations they are compared with 15 reference compositions containing both standard high explosives such as octogen(HMX)(2),hexogen(RDX)(3),pentaerythritol tetranitrate(PETN)(4),2,4,6-trinitrotoluene(TNT)(5)as well as insensitive high explosives such as 3-nitro-1,2,4-triazolone(NTO)(6),1,3,5-triamino-2,4,6-trinitrobenzene(TATB)(7),1,1-diamino-2,2-dinitroethylene(FOX-7)(8)and N-Guanylurea dinitramide(FOX 12)(9).NGu based formulations are superior to those based on FOX-12 or TATB and are a close match with FOX-7 based explosives,the latter just having higher Gurney Energies(-10%)and slightly higher detonation pressure(+2%).NGu based explosives even reach up to 78% of the detonation pressure,82% Gurney energy and up to 95% of detonation velocity of HMX.LBD-NGu dissolves in many melt cast eutectics forming dense charges thereby eliminating the need for costly High Bulk Density NGu.Nitroguanidine based formulations are at the rock bottom of sensitiveness among all the above-mentioned explosives which contributes to the safety of these formulations.The review gives 132 references to the public domain.For a review on the synthesis spectroscopy and sensitiveness of Nitroguanidine see Ref.[1].

Facile Preparation of Polypeptides:Moisture Insensitive and Superfast Ring Opening Polymerization of N-Carboxyanhydrides

(a)NCA polymerization initiated by LiHMDS or other initiators in THF,initiator i)n-hexylamine,ii)HMDS,iii)bipyNi(COD);(b)LiHMDS-initiated open vessel polymerization of BLGNCA at 26 mg and 2 g scale;(c)GPC traces of poly-BLG at variable DP;(d)Reaction rates of LiHMDS and hexylamine initiated BLGNCA polymerization in THF with NCA:initiator ratio of 100∶1 and initial NCA concentration at 0.2 mol/L;(e)CD spectra of poly-BLG at variable DP prepared from LiHMDS-initiated NCA polymerization.

The Confinement Effect of Inert Materials on the Detonation of Insensitive High Explosives

The paper aims to theoretically and numerically investigate the confinement effect of inert materials on the detonation of insensitive high explosives. An improved shock polar theory based on the Zeldovich-von Neumann-Döring model of explosive detonation is established and can fully categorize the confinement interactions between insensitive high explosive and inert materials into six types for the inert materials with smaller sonic velocities than the Chapman-Jouguet velocity of explosive detonation. To confirm the theoretical categorization and obtain the flow details, a second-order, cell-centered Lagrangian hydrodynamic method based on the characteristic theory of the two-dimensional first-order hyperbolic partial differential equations with Ignition-Growth chemistry reaction law is proposed and can exactly numerically simulate the confinement interactions. The numerical result confirms the theoretical categorization and can further merge six types of interaction styles into five types for the inert materials with smaller sonic velocity, moreover, the numerical method can give a new type of interaction style existing a precursor wave in the confining inert material with a larger sonic velocity than the Chapman-Jouguet velocity of explosive detonation, in which a shock polar theory is invalid. The numerical method can also give the effect of inert materials on the edge angles of detonation wave front.

Detection of Graphene Cracks By Electromagnetic Induction,Insensitive to Doping Level

Detection of cracks is a great concern in production and operation processes of graphene based devices to ensure uniform quality.Here,we show a detection method for graphene cracks by electromagnetic induction.The time varying magnetic field leads to induced voltage signals on graphene,and the signals are detected by a voltmeter.The measured level of induced voltage is correlated with the number of cracks in graphene positively.The correlation is attributed to the increasing inductive characteristic of defective graphene,and it is verified by electromagnetic simulation and radio frequency analysis.Furthermore,we demonstrate that the induced voltage signal is insensitive to the doping level of graphene.Our work can potentially lead to the development of a high-throughput and reliable crack inspection technique for mass production of graphene applications.

Theoretical design of new bridge-ring insensitive high energy compounds by selected normal Diels-Alder reactions between NH_(2)-substituted oxazoles and NO_(2)/NF_(2)/NHNO_(2)-substituted ethylenes/acetylenes

In this work,NH_(2)-substituted oxazoles and NO_(2)/NF_(2)/NHNO_(2)-substituted ethylenes/acetylenes were designed and used as dienes and dienophiles,respectively,in order to develop new bridge-ring insensitive high energy compounds through the Diels-Alder reaction between them.The reaction type,reaction feasibility and performance of reaction products were investigated in detail theoretically.The results showed that dienes most possibly react with dienophiles through the HOMO-diene controlled normal Diels-Alder reaction at relatively low energy barrier.Tetranitroethylene could react with the designed dienes much more easily than other dienophiles,and was employed to further design 29 new bridge-ring energetic compounds.Due to high heat of formation,density and oxygen balance,all designed bridge-ring energetic compounds have outstanding detonation performance,16 of them have higher energy than HMX(1,3,5,7-tetranitro-1,3,5,7-tetrazocine)and 2 others even possess comparative energy with the representative of high energy compounds CL-20(2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane).The predicted average h50 value of these bridge-ring energetic compounds is 83 cm,showing their low impact sensitivity.The NH2 groups could obviously impel the proceeding of Diels-Alder reactions,but would slightly decrease the energy and sensitivity performance.In all,the new designed bridge-ring compounds have both high energy and low sensitivity,and may be produced through Diels-Alder reactions at relatively low energy barrier.This paper may be helpful for the theoretical design and experiment synthesis of new advanced insensitive high energy compounds.

A proposal for the generation of optical frequency comb in temperature insensitive microcavity

We numerically simulate the generation of an optical frequency comb(OFC) in a microring based on the traditional Si_3N_4 strip waveguide and a temperature compensated slot waveguide.The results show that OFCs are susceptible to temperature with strip waveguide while they can keep stable when temperature changes 10 Kin either low-Q(10~5) or highQ(10~6) microcavity with the well-designed slot waveguide,which has great superiority in practical applications where the temperature drift of the cavity due to the intense pump or surrounding change is unavoidable.

Polarization Insensitive Broadband Zero Indexed Nano-Meta Absorber for Optical Region Applications

Broadband response metamaterial absorber(MMA)remains a challenge among researchers.A nanostructured new zero-indexed metamaterial(ZIM)absorber is presented in this study,constructed with a hexagonal shape resonator for optical region applications.The design consists of a resonator and dielectric layers made with tungsten and quartz(Fused).The proposed absorbent exhibits average absorption of more than 0.8972(89.72%)within the visible wavelength of 450–600 nm and nearly perfect absorption of 0.99(99%)at 461.61 nm.Based on computational analysis,the proposed absorber can be characterized as ZIM.The developments of ZIM absorbers have demonstrated plasmonic resonance characteristics and a perfect impedance match.The incidence obliquity in typically the range of 0◦–90◦both in TE and TM mode with maximum absorbance is more than 0.8972(∼89.72%),and up to 45◦angular stability is suitable for solar cell applications,like exploiting solar energy.The proposed structure prototype is designed and simulated by studying microwave technology numerical computer simulation(CST)tools.The finite integration technique(FIT)based simulator CST and finite element method(FEM)based simulator HFSS also helps validate the numerical data of the proposed ZIM absorber.The proposed MMA design is appropriate for substantial absorption,wide-angle stability,absolute invisible layers,magnetic resonance imaging(MRI),color images,and thermal imaging applications.

Low-Cost and High-Performance Polymer Solar Cells with Efficiency Insensitive to Active-Layer Thickness

The power conversion efficiency(PCE)of polymer solar cells(PSCs)has recently increased quickly,propelling PSCs closer to large-scale commercialization.However,several critical issues,such as the cost of materials and the sensitivity of the PCE to active-layer thickness,must be addressed before industrial application can be realized on a large scale.Here,we fabricated a high-performance ternary PSC based on a low-cost polymer donor PTQ10 and an A-DA’D-A-type small molecule acceptor(SMA)2,2'-((2Z,2'Z)-((12,13-bis(2-butyloctyl)-3,9-bis(4-(2-ethylhexyl)thiophen-2-yl)-12,13-dihydro-[1,2,5]thiadiazolo[3,4-e]thieno[2'',3'':4',5']thieno[2',3':4,5]pyrrolo[3,2-g]thieno[2',3':4,5]thieno[3,2-b]indole-2,10-diyl)bis(methaneylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile(m-TEH)with a newA-DA’D-A-type SMA 2,2'-((2Z,2'Z)-((12,13-bis(2-butyloctyl)-3,9-bis(3-(2-ethylhexyl)phenyl)-12,13-dihydro-[1,2,5]thiadiazolo[3,4-e]thieno[2'',3'':4',5']thieno[2',3':4,5]pyrrolo[3,2-g]thieno[2',3':4,5]thieno[3,2-b]indole-2,10-diyl)bis(methaneylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile(m-PEH)(with phenyl outer side chains)as the third component.Benefitting from the good compatibility and the unique alignment of the energy levels between PTQ10 and the two SMAs,the ternary system showed favorable phase separation and dominant face-on orientation,exhibiting suitable film morphology and enhanced charge transport.Therefore,the optimized ternary PSCs based on PTQ10∶m-TEH∶m-PEH(1.0∶0.9∶0.3,w/w/w)demonstrated an outstanding PCE of 19.34%,which is one of the highest PCEs reported for the single junction PSCs to date.More importantly,the ternary PSCs demonstrated superior tolerance to the active-layer thickness and showed a high PCE of 18.02% with a high fill factor(FF)of 76.56% for the devices with the active-layer thickness even reaching 300 nm.These results indicate that the ternary devices based on PTQ10∶m-TEH∶m-PEH are highly promising for future large-area fabrication and commercial application of PSCs.

High color saturation and angle-insensitive ultrathin color filter based on effective medium theory

An ultrathin angle-insensitive color filter enabling high color saturation and a wide color gamut is proposed by relying on magnesium hydride-hydrogenated amorphous silicon[MgH2-a-Si:H]lossy dielectric layer.Based on effective medium theory,the MgH2-a-Si:H layer with an ultrathin thickness can be equivalent to a quasi-homogeneous dielectric layer wit an effective complex refractive index,which can be tuned by altering the thickness of MgH2to obtain the targeted value o the imaginary part,corresponding to the realization of high color saturation.It is verified that the proposed color filte offers highly enhanced color saturation in conjunction with a wide color gamut by introducing a few-nanometer thic MgH2layer.As the MgH2-a-Si:H layer retains the advantages of high refractive index and tiny thickness,the proposed colo filter exhibits large angular tolerance up to±60°.In addition,MgH2with an unstable property can interconvert with Mg unde a dehydrogenation/hydrogenation reaction,which empowers the proposed color filter with dynamically tunable outpu color.The proposed scheme shows great promise in color printing and ultracompact display devices with high color sat uration,wide gamut,large angular tolerance,and dynamic tunability.

High-energy,alignment-insensitive,injection-seeded Q-switched Ho:yttrium aluminum garnet single-frequency laser

A high-energy,alignment-insensitive,injection-seeded Q-switched Ho:yttrium aluminum garnet(YAG)singlefrequency laser is developed.Both the slave Q-switched laser and the seed laser are Ho:YAG ring lasers based on a pair of corner cubic reflectors.The seed laser has an available power of 830 mW at 2096.667 nm.At 100 Hz,the Q-switched Ho:YAG laser provides a single-frequency pulsed output using injection-seeded technology.The 7.3 mJ single-frequency pulse energy from the slave laser has a pulse width of 161.2 ns and is scaled to 33.3 mJ after passing through the Ho:YAG single-pass amplifier.According to the measurement results of the heterodyne beating technique,the single-frequency pulse has a half-width of 4.12 MHz.

Regulating the melting point by non-covalent interaction toward a promising insensitive melt-castable energetic material:1,2-Difluoro-4,5-dinitrobenzene

Searching for insensitive melt-castable energetic materials is still facing great challenges.In this work,we developed a promising strategy that is regulating the ratio of non-covalent interaction by fluorine atoms to regulate the melting point to develop new melt-castable energetic materials.Using this method,a highly sym-metric 1,2-difluoro-4,5-dinitrobenzene(DFDNB)was synthesized in one step and fully characterized.DFDNB has a desirable melting point(83.2℃),high decomposition temperature(>400℃),acceptable detonation properties(6786 m s^(-1),21.5 GPa)but superior safety performance(>40 J,>360 N),and excellent chemical compatibility with 1,3,5-trinitro-1,3,5-triazine(RDX)that make it a promising insensitive melt-castable energetic material.A detailed study based on crystal stacking,electrostatic potential,and intermolecular weak interactions in DFDNB and its isomers or analogs demonstrates that non-covalent interactions including the C-F…H,N-O…H hydrogen bonding,and C-F…O halogen-like bonding play an important role in regulating the melting point.

吉他演奏家马丁诺Solo小七和弦概念化演奏分析

马丁诺在15岁就开始职业演出,演奏技巧绝佳。同时,他也是位态度上非常开放的乐手,能够接受各种不同风格的元素,他的表现方式,直接开启了Sonny Sharrock等后来的前卫吉他手的道路。本论根据马丁诺在《Linear Expressions》中对和弦的替换思维方式,结合他于1970年01月01日在《Exit》中重新演绎的《Days Of Wine And Roses》《How insensitive》Solo线条部分,分析IIM7和弦之外连接。通过对马丁诺在《Linear Expressions》中提到的他对和弦进行下的小和弦替代思维方式,这种概念化的思维方式对吉他手、爵士乐手来说具有研究和学习的价值。本文主要分析了四种和弦进行下的替换思维,包括大大七和弦组,大小七和弦以及变化的属七和弦,半减七和弦。

The Fabrication and Characterization of Polarization Insensitive Semiconductor Optical Amplifier

An angled facet strained bulk InGaAs SOA has been designed and fabricated. A device with double-layer antireflection coatings had <2dB polarization sensitivity and <0.5dB gain ripple.

Refractive index insensitive temperature sensor based on waist-enlarged few mode fiber bitapers

A refractive index insensitive temperature sensor based on waist-enlarged few mode fiber(FMF) bitapers is presented. The first section of FMF is spliced between two single-mode fibers. In fusion process,the waist-enlarged FMF bitapers can be obtained by large current discharging repeatedly. The refractive index and temperature sensing mechanisms are analyzed. For the sensors with different sizes,the refractive index and temperature experiments have been performed. The results show that in the refractive index ranges of 1.335 0—1.346 6 and 1.348 2—1.419 3,the refractive index insensitivity is verified. In a temperature range of 31.9—90 °C,the sensor sensitivity can be up to 85.57 pm/°C. In addition,it has a compact structure. Therefore,the sensor can avoid the cross sensitivity for measuring the refractive index and temperature simultaneously.

High energy and insensitive explosives based on energetic porous aromatic frameworks

The design and synthesis of energetic materials with a compatibility of high energy and insensitivity have always been the research fronts in military and civilian fields.Considering excellent performances of porous organic frameworks and the lack of research in the field of energetic materials,in this study,a new concept named energetic porous aromatic frameworks(EPAFs)is proposed.The strategy of coating high energy explosives such as 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane(CL-20)and 1,3,5,7-tetranitro-1,3,5,7-tetrazocane(HMX)in the EPAFs by wet-infiltration method has successfully realized the assembly of target energetic composite materials.The results show that the 75 wt.%CL-20@EPAF-1 possesses the safer impact sensitivity of 31.4 J than that of CL-20(4.0 J).Notably,for 75 wt.%CL-20@EPAF-1,in addition to the superior detonation performances of the detonation velocity(8,761 m·s^(-1))and detonation pressure(31.27 GPa),the synergistic effect of the nitrogen-rich EPAFs and the nitramines high energy explosives results in a higher heat of detonation that surpasses the most of pristine high explosives and reported novel energetic materials.In prospect,energetic porous aromatic frameworks could be a promising and inspiring strategy to build high energy insensitive energetic materials.

Polarization-insensitive interferometer based on a hybrid integrated planar light-wave circuit

Interferometers are essential elements in classical and quantum optical systems.The strictly required stability when extracting the phase of photons is vulnerable to polarization variation and phase shift induced by environment disturbance.Here,we implement polarization-insensitive interferometers by combining silica planar light-wave circuit chips and Faraday rotator mirrors.Two asymmetric interferometers with temperature controllers are connected in series to evaluate the single-photon interference.Average interference visibility over 12 h is above 99%,and the variations are less than 0.5%,even with active random polarization disturbance.The experiment results verify that the hybrid chip is available for high-demand applications like quantum key distribution and entanglement measurement.

EFFECT OF METAL-COMPLEXING COMPOUNDS ON THE CYANIDE-INSENSITIVE RESPIRATION IN CORN MITOCHONDRIA

In our previous paper we showed that a cyanideoresistant respiration was associated with mitochondrial preparations from corn seedlings. It was observed that the degree of sensitivity to cyanide was dependent upon the nature of substrates. The resistance of respiration to cyanide by isolated corn mitoehondria became higher in