Preliminary discussion on the ignition mechanism of exploding foil initiators igniting boron potassium nitrate

Exploding foil initiator(EFI)is a kind of advanced device for initiating explosives,but its function is unstable when it comes to directly igniting pyrotechnics.To solve the problem,this research aims to reveal the ignition mechanism of EFIs directly igniting pyrotechnics.An oscilloscope,a photon Doppler velocimetry,and a plasma spectrum measurement system were employed to obtain information of electric characteristics,impact pressure,and plasma temperature.The results of the electric characteristics and the impact pressure were inconsistent with ignition results.The only thing that the ignition success tests had in common was that their plasma all had a relatively long period of high-temperature duration(HTD).It eventually concludes that the ignition mechanism in this research is the microconvection heat transfer rather than the shock initiation,which differs from that of exploding foil initiators detonating explosives.Furthermore,the methods for evaluating the ignition success of semiconductor bridge initiators are not entirely applicable to the tests mentioned in this paper.The HTD is the critical parameter for judging the ignition success,and it is influenced by two factors:the late time discharge and the energy of the electric explosion.The longer time of the late time discharge and the more energy of the electric explosion,the easier it is to expand the HTD,which improves the probability of the ignition success.

iSCSI Initiator的实现概要

iSCSI已成为SAN中重要的协议。文中分析了iSCSIInitiator在操作系统中的层次框架 ,并简述了一种实现方案。

Initiator——保守的核心启动子元件

真核生物中蛋白质编码基因的核心启动子元件有4类:传统的TATA盒、上游核心启动子元件BRE、下游启动子元件DPE和起始子(initiator,Inr)。Initiator元件指的是一段富含嘧啶的序列——PyPyA+1NT/ApyPy,转录起始点位于其中的+1位。研究表明它被多种转录因子识别和结合,包括TAFⅡ250、TAFⅡ150、TFⅡ-Ⅰ、YY1和RNA聚合酶Ⅱ等,反映出initiator调控的复杂性。Initiator多存在于人类的管家基因、癌基因、生长因子基因和转录因子基因中,在这些基因的转录起始过程中发挥着关键作用。

Influence of Initiator on Synthesis and Properties of Polyurethane-acrylate Hybrid Emulsion

The prepolymer polyurethanes （PUs） based on isophorone diisocyanate （IPDI）, poly（propylene glycol） （PPG）, 1,4-butanediol （BDO） and dimethylopropionic acid （DMPA） were synthesized at 75-80 ℃ for 7-8 hours, using dibutyltin dilauate （DBTDL） as catalyzer, and polyurethane-acrylate hybrid emulsion was prepared after methyl methacrylate （MMA） was polymerized, using potassium persulfate and azobisisobutyronitrile （AIBN） as initiator, respectively. The influences of these factors such as the kind of initiator, the feed method of initiator and the addition of initiator on properties of polyurethane-acrylate were studied. The FTIR and GPC of aqueous polyurethane were analyzed. The FTIR spectra show that the degree of microphase-separate between the soft segments and rigid segments is high. The analysis of molecular weights stated that molecular weights increased most significantly after amine was added. The experimental results reveal that the appearance of emulsion is excellent, the film is harder and the water absorption radio of the film is less when oil-solubility AIBN is used as initiator. The semi-continuous can increase the molecular weight of polymer and the optimum amount of the initiator was 3% for MMA.

Synthesis and characterization of miktoarm star copolymer of styrene and butadiene using multifunctional macromolecular initiator

A new kind of multifunctional macromolecular initiator with Sn-C bonds and polydiene arms was synthesized by living anionic polymerization. At first, polydiene-stannum chloride （PD-SnCl3） was prepared by the reaction of n-butyl-Li （n-BuLi）, stannic chloride （SnCl4） and diene. Then PD-SnCl3 was used to react with the dilithium initiator to prepare the multifunctional organic macromolecular initiators. The result suggested that the initiators had a remarkable yield by GPC, nearly 90%. By using these multifunctional macromolecular initiators, styrene and butadiene were effectively polymefized via anionic polymerization, which gave birth to novel miktoarm star copolymers. The relative molecular weight and polydispersity index, microstructure contents, copolymerization components, glass transition temperature （Tg） and morphology of the miktoarm star copolymers were investigated by GPC-UV, ~H NMR, DSC and TEM, respectively. 2009 Xing Ying Zhang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

Sensitivity Test and Data Analysis for Storage Reliability Assessment of Explosive Initiator

The explosive initiator is one kind of sensitivity products with long life and high reliability.In order to improve the storage reliability assessment,the method of storage reliability assessment for explosive initiator was proposed based on time series model using the sensitivity test data.In the method,the up and down test was used to estimate the distribution parameters of threshold.And an approach to design the up and down test was present to draw better estimations.Furthermore,the method of shrinkage estimation was introduced to get a better estimation of scale parameter by combining the sample information with prior information.The simulation result shows that the shrinkage estimation is better than traditional estimation under certain conditions.With the distribution parameters estimations,the time series models were used to describe the changing trends of distribution parameters along with storage time.Then for a fixed storage time,the distribution parameters were predicted based on the models.Finally,the confidence interval of storage reliability was obtained by fiducial inference.The illustrative example shows that the method is available for storage reliability assessment of the explosive initiator with high reliability.

A micro-chip exploding foil initiator based on printed circuit board technology

Conventional exploding foil initiator (EFI) in ignition or detonation applications hosts many performance advantages, but was hindered by the bulky, inaccurate, inefficient and expensive shortcomings. We highlight a novel micro-chip exploding foil initiator (McEFI) using printed circuit board (PCB) technology. The structural parameters were determined based on energy coupling relationship at the component interfaces. Next, the prototype McEFI has been batch-fabricated using PCB technology, with a monolithic structure of 7.0 mm (l) × 4.5 mm (w) × 4.0 mm (δ). As expected, this PCB-McEFI illustrated the successful firing validations for explosives pellets. This paper has addressed the cost problem in both military munitions and civil markets wherever reliable, insensitive and timing-dependent ignition or detonation are involved.

STEREOREGULARITY OF POLY (METHYL METHACRYLATE) OBTAINED WITH CHIRAL ANIONIC COMPLEX INITIATOR

The stereoregular polymerization of methyl methacrylate (MMA) have been investigatedwith chiral anionic complex initiator[FILi-(-)SP]in toluene, THF and toluene/THF [1/1(v/v)]. The tacticities of PMMAs obtained in the three solvents have been found to be mainly asyndiotactic triads(s-PMMA)with content of 72.3, 67.7 and 71.4%,respectively.

STUDIES ON THE KINETICS AND INITIATION MECHANISM OF ACRYLAMIDE POLYMERIZATION USING CERIC/ACETOACETANILIDE SYSTEM AS INITIATOR

It is found that acetoacetanilide possesses very high promoting reactivity towards ceric ion in initiating polymerization of vinyl monomer. The kinetics of acrylamide polymerization and the activation energies were studied. The initiation mechanism of ceric/acetoacetanilide is proposed on the basis of experimental results of FT-IR and ESR.

Method for high reliability evaluation of explosive initiator based on sensitivity distribution order restricted theory

Based on the hypothesis testing theory and sampling inspection, and utilizing the distribution parameters obtained by order restricted method, the matter of reliability index verification is transformed into testing the scale parameters of distribution. Thus, a lower stimulus level is selected, and small sample size specimens are tested to verify the high reliability at required stimulus level. Analysis for mean square error of verification test stimulus level is taken, and the result demonstrates that it is reasonable to confirm the test scheme using the order restricted estimation. The new method is used for reliability verification of the stab detonator comparing with run-down method. The result shows that it is available for verification of high reliability explosive initiator by small sample size.

COPOLYMERIZATION PROCESS OF TRIPHENYLMETHYL METHACRYLATE AND MMA WITH CHIRAL ANIONIC COMPLEX INITIATOR

The copolymerization process of triphenylmethyl methacrylate (TrMA) and methylmethacrylate (MMA) using chiral anionic complex initiator (-) SP-FlLi (Scheme 1) has beenstudied in toluene and THF, respectively. The copolymer obtained in toluene possessed muchhigher specific rotation than that in THF. These copolymers have shown a tendency to a random and a like alternating structure, respectively.

NON-ACETAL INITIATORS FOR GROUP TRANSFER POLYMERIZATION

It is reported that a variety of trimethylsilyl enol ethers of ketones and aldehydes can be used to initiate GTP of methacrylates and acryl- ates.The new initiators are easy to prepare from ketones or aldehydes.PMMA and PMA with controlled molecular weight and low polydispersity were obtained by using non-acetal initiators in the presence of bibenzoate,bifluo ide or Hgl_2,The living nature of polymerization is shown by the correspondence of theoretical and observed molecular weight and the preparation of A-B-A type triblock copolymer with methacrylate and acrylate segments can be prepared.

Research Progress of Catalysts and Initiators for Promoting the Cracking of Endothermic Hydrocarbon Fuels

Catalytic/initiated cracking of endothermic hydrocarbon fuels is an eff ective technology for cooling a hypersonic aircraft with a high Mach number(over 5).Catalysts and initiators can promote fuel cracking at low temperatures,increase fuel conversion and the heat sink capacity,and suppress coke deposition,thereby reducing waste heat.Catalysts mainly include metal oxide catalysts,noble metal catalysts and metal nanoparticles,zeolite catalysts,nanozeolite catalysts,and coating catalysts.Moreover,initiators roughly include nitrogenous compounds,oxygenated compounds,and hyperbranched polymer initiators.In this review,we aim to summarize the catalysts and initiators for cracking endothermic hydrocarbon fuels and their mechanisms for promoting cracking.This review will facilitate the development of the synthesis and exploration of catalysts and initiators.

Atom Transfer Radical Polymerization of Methyl Methacrylate with α,α-Dichlorotoluene or α,α,α-Trichlorotoluene as Initiator

The atom transfer radical polymerization (ATRP) of methyl methacrylate using α.α dichlorotoluene or α.α.α-trichlorotoluene as the initiator and CuCl/2.2'-bipyridine complex as the catalyst was investigated. α,α-Dichlorotoluene gave good control of molecular weight with high initiation efficiency and low polydispersity. While α.α.α-trichlorotoluene gave very slow polymerization rate. which could be improved by the addition of Cu (0) to the system.

Liu Wansu,physician and initiator of the'Cold School'

Liu Wansu (courtesy name:Liu Shouzhen,circa 1120-1200) was a native of Hejian (present Hejian City,Hebei Province) in the Jin Dynasty (1115-1234),so he was also called Li Hejian by later generations.He was a distinguished physician in the Jin and Yuan dynasties,and one of the four great medical masters in that period.

iSCSI Initiator的实现概要

2003年2月iSCSI(Internet SCSI)正式(Internet Engineering TaskForce)的批准，成为Internet标准协议。iSCSI是建立在TCP之上的传输协议，它根据SAM-2模型对SCSI-3命令进行封装，并在IP网内传输和路由转发按iSCSI标准，iSCSI Initiator模拟一个SCSIHBA，iSCSI Target模拟一个SCSI设备。iSCSI Initiator向iSCSI Target申请存储服务，在iSCSI Initiator和iSCSI Target之间通过会话(Session)连接。会话由一个或多个连接(Connection)构成，每个iSCSI连接对应一个TCP连接。iSCSI将两种应用最广泛的协议——存储领域中的SCSI协议和网络领域中的TCP／IP，结合到一起。随着GbE技术、TCP／IP卸载引擎(TCP Offioading Engine)技术和10Gb Ethernet技术的出现和普及，iSCSI很有可能成为SAN最具有前景的技术和协议。

Influence of Water-soluble Azo Initiators on Cationic Latex particles

Batch cationic emulsion polymerization was carried out with styrene(St)and butyl acrylate(BA)as non-ionic monomer,Cetyl trimethyl ammonium chloride(CTAC)as emulsifier,and Azobis isobutyl amidine hydrochloride(AIBA)or Azo diisopropyl imidazoline hydrochloride(AIBI)as initiator.The effects of amount and molecule structure of initiators on latex particle size,PDI and particle morphology were analyzed.Results showed that higher initiator amount resulted in smaller particle size and higher PDI.Besides,smaller particle size were obtained when AIBI was used as initiator.