典型换能元与点火药剂匹配试验研究

选用桥丝（BW）与金属薄膜（MF）两种镍铬合金换能元,以及Pb(SCN)₂/KClO₃与Zr/Pb₃O₄两种点火药剂,分别制备了4种不同的点火元件。点火元件与5.8系发射药制成药包,并在密闭爆发器中点燃,获得相应的压力=时间曲线,以此探讨不同点火药与典型换能元的匹配情况。其中,涂覆有4.8 mg Pb(SCN)₂/KClO₃的金属薄膜点火头增压速率为80.84 MPa/s,而涂有相同质量药剂的桥丝点火头增压速率仅为68.15 MPa/s。结合高速摄影图像与理论分析认为:换能元的电热转换效率可以在较大程度上影响点火药剂的发火状态;金属薄膜换能元由于具有较为集中的发火区域,因此点火能力相较于桥丝换能元更加稳定;Pb(SCN)₂/KClO₃药剂的发火状态也比Zr/Pb₃O₄药剂稳定。     

一种带约束管的爆炸箔点火器的结构设计

为降低X型爆炸箔点火器的发火电压，提高点火可靠性，设计了一种带约束管的爆炸箔点火器。它由壳体、约束管、点火药、盖片和堵盖等组成，外径为18.00 mm,高度为25.00 mm;输入点火药选用爆发点较低的热敏感型B/KNO₃点火药，装药密度为(1.45±0.05) g/cm³,装药量为(0.13±0.05) g;输出点火药选择许用B/KNO₃点火药，装药密度为(1.75±0.05) g/cm³,装药量为(0.62±0.05) g;输入装药约束管外径为5.00 mm,高度为4.50 mm,厚度为0.50 mm;输出装药约束管外径为8.00 mm,高度为7.00 mm,厚度为0.50 mm。并对爆炸箔点火器进行结构强度仿真和主要性能测试。结果表明：点火器在点火过程受到的最大应力约为54.513 MPa,最大应变约为3.699 3×10^-4;输出压力为17.90 MPa; 50%发火电压为672 V。满足了使用要求。     

抗过载长秒量延期电点火具结构设计与性能研究

为提高电点火具的抗过载能力，并满足长延期的要求，在研究提高电点火具抗过载的方法和影响延期药燃烧速度因素的基础上，设计了一种抗过载长秒量延期电点火具。采用复式结构壳体(内外双壳，内壳为铝、外壳为镍铜)来提高其抗过载能力，壳内涂虫胶漆。选用玻璃 金属封结电极塞来提高密封性。点火药为m（聚四氟乙烯）∶m（铝粉）∶m（镁粉）= 40∶30∶30的高能点火药。延期元件选用1Cr18Ni9Ti不锈钢材料管壳。延期药为钨系延期药，组分质量比为m(W)∶m(KClO₄):m(BaCrO₄)∶m(黏结剂)=33∶10∶55∶2。使用泡沫铝作为延期元件和壳体间的缓冲材料，厚度为1.5 mm。运用ANSYS软件，仿真验证了电点火具的抗过载能力，满足设计要求。采用堵、泄结合的方式进行防静电设计:在点火药和壳体之间设计环氧树脂绝缘环，厚度为1.5 mm；在电极塞中部设计0.2 mm宽的空气隙，提高使用安全性。通过对电点火具结构、药剂、材料等方面的优化，提升了电点火具的抗过载能力，满足了长秒量延期要求。     

不同点火条件下无起爆药雷管实验

使用外径6.0mm、内径3.5mm,长度分别为30,25,20,15mm的钢内管,装填结晶PETN(太安)作为起爆元件代替起爆药,分别使用桥丝电引火头、塑料导爆管、半导体桥(SCB)点火。实验表明:在桥丝电引火头作用下,30,25mm钢内管装药密度分别为0.90¹.47g/cm1.47g/cm³、1.213、1.21¹.40g/cm1.40g/cm³;高能HGL点火药作用下,20mm钢内管装药密度为0.873;高能HGL点火药作用下,20mm钢内管装药密度为0.87¹.42g/cm1.42g/cm³,钢内管中结晶PETN能够实现燃烧转爆轰(DDT)。半导体桥点火使用RDX(黑索今)和PETN作为点火端装药可以使雷管发生爆轰。     

SnO2修饰石墨毡电极的制备及其性能表征

采用H₂O₂对石墨毡（GF）进行预处理,然后在其表面电沉积Sn,最后在120℃烘箱氧化24 h制备出SnO₂修饰的石墨毡电极。通过扫描电镜（SEM）对SnO₂修饰前后的石墨毡表面形貌进行表征,采用循环伏安法研究了SnO₂修饰后石墨毡电极的电化学性能。结果表明：SnO₂能够均匀地包覆在石墨毡表面;SnO₂修饰石墨毡后V⁴⁺/V⁵⁺电对的氧化峰的峰电流由0.0538 A增加到0.0708 A,与未处理石墨毡相比增加了31.5%,反应峰出峰持续时间提高,说明SnO₂对V⁴⁺/V⁵⁺电对电极过程具有一定的催化作用。析氧电位由1.382 V增加到了1.517 V,使电极在VOSO₄溶液中的电化学窗口变宽。     

A/B位双取代钛酸铋钠基压电陶瓷性能研究

采用固相烧结方法制备了Bi、Co同时取代化学计量比钛酸铋钠基(Bi_0.5+x/2Na_0.5-x/2)_0.94Ba_0.06Ti_1-xCo_xO₃无铅压电陶瓷, 研究了材料中A/B位缺陷对其电滞回线和电致应变的影响。结果表明陶瓷具有均一的赝立方结构, 随着掺杂量的增加, 材料铁电-弛豫相转变温度降低, 应变增加。同时材料在疲劳过程中伴随着弛豫相的增多, 在较低电场下产生较大的应变(0.458%), 逆压电常数d₃₃^*达到770 pm/V。介电温谱和电滞回线上反常变化与化学计量比陶瓷中产生的A/B位缺陷偶极子密切相关, 并表明这种缺陷偶极子是以氧空位为媒介形成的。     

不同点火条件下无起爆药雷管实验

使用外径6.0mm、内径3.5mm,长度分别为30,25,20,15mm的钢内管,装填结晶PETN(太安)作为起爆元件代替起爆药,分别使用桥丝电引火头、塑料导爆管、半导体桥(SCB)点火。实验表明:在桥丝电引火头作用下,30,25mm钢内管装药密度分别为0.90~1.47g/cm~3、1.21~1.40g/cm~3;高能HGL点火药作用下,20mm钢内管装药密度为0.87~1.42g/cm~3,钢内管中结晶PETN能够实现燃烧转爆轰(DDT)。半导体桥点火使用RDX(黑索今)和PETN作为点火端装药可以使雷管发生爆轰。     

石墨和MoS2对AerMet100基复合材料摩擦学性能的影响

为了提高AerMet100钢的摩擦学性能,以AerMet100钢粉为基体,添加MoS₂和石墨为固体润滑剂,采用粉末冶金工艺制备石墨/MoS₂/AerMet100复合材料;使用扫描电镜（SEM）、X射线衍射（XRD）、能谱仪（EDS）分析试样的微观形貌、相组成和元素含量,使用HT1000高温摩擦磨损试验机测试复合材料的摩擦学性能;研究了MoS₂和石墨含量对AerMet100基复合材料力学性能和摩擦学性能的影响,探讨了其减摩耐磨机理。结果表明：随着石墨含量的增加,复合材料的力学性能和摩擦学性能下降。当添加质量分数6.0%MoS₂和2.0%石墨时,AerMet100基复合材料的摩擦学性能最优,这主要归因于硬质相碳化物和润滑相硫化物的生成。     

B2O3和Al2O3共同掺杂ZnO压敏陶瓷的性能

研究了B₂O₃(B)和Al₂O₃(Al)共掺杂对ZnO压敏陶瓷电学性能和微观结构的影响。结果表明,共掺杂B和Al的ZnO压敏陶瓷,具有低泄漏电流、高非线性和低剩余电压等优良电性能。B和Al的掺杂率为3.0%(摩尔分数)和0.015%(摩尔分数)的ZnO压敏陶瓷,其最佳样品的电参数为：击穿电压E_{1 mA}＝475 V/mm;泄漏电流J_L=0.16 μA/cm²;非线性系数α=106;剩余电压比K = 1.57。     

添加Bi2WO6对ZnO基压敏陶瓷电学性能的影响

用传统固相反应法研究了添加Bi₂WO₆(x=0%~9%,质量分数)对ZnO基压敏陶瓷的微观结构、压敏性能和介电性能的影响。结果表明：掺入适量的Bi₂WO₆能促进ZnO压敏陶瓷晶粒均匀生长、提高微观结构的均匀性、降低压敏场强和提高非线性系数;同时,Bi₂WO₆的添加可提高ZnO晶粒表面吸附氧的含量,从而提高界面态密度和势垒高度以及ZnO基压敏陶瓷的非线性特性。Bi₂WO₆的添加量为7%的ZnO基压敏陶瓷,其综合性能为：E_{1 mA}=263 V/mm,α=53,J_L=3.50 μA/cm²,φ_b=11.52 eV。     

Stress invariants in an orthotropic damage space

In the classical theory of plasticity, it is often convenient to express failure criteria and/or flow rules in terms of stress invariants (I₁,I₂,I₃) and deviatoric stress invariants (J_2D, J_3D). Within the framework of continuum damage mechanics, the microscopic degradation of materials is reflected through the damage variables that conceive the notion of net-stress (the term net-stress has been used here in place of the term effective-stress since the latter already has an established meaning in Geotechnical Engineering). Any operative yield or failure criterion in the continuum damage mechanics will then need to be expressed in terms of the net-stress. This motivates an attempt to find the equivalent stress invariants in terms of the net-stress. In this paper, the stress invariants in an orthotropic damage space have been successfully derived and presented.     

Catalytic CVD growth and properties of a-C:H and a-C:N

Hydrogenated amorphous carbon (a-C:H) and nitrided amorphous carbon (a-C:N) films have been synthesized on quartz substrates at a substrate temperature of 700 °C using a catalytic chemical vapor deposition (Cat-CVD) method. Raman spectra of a-C:H films showed two principal bands, the G-band at 1600 cm⁻¹ and the D-band at 1350 cm⁻¹. Those of a-C:N films showed similar spectra, with a G′ band at 1640 cm⁻¹, the peak energy of which is higher than that of the G-band in a-C:H. The intensity ratio /I_D, which is a measure of the degree of order in a-C:H, decreased for a-C:H with increasing CH₄/H₂ gas-flow ratio. On the contrary, the /I_D ratio increased with increasing CH₄/H₂ gas-flow ratio.     

Influence of Dissolution Medium Agitation on Release Profiles of Sustained-Release Tablets

Reaching nearly perfect sink conditions is very important in the determination of drug dissolution rates. Many times, the only factor that is taken into consideration in achieving sink conditions is the relation between the drug concentration and its solubility. The analytical conditions of the dissolution assay, as well as the dissolution apparatus, stirring speed, and nature and volume of the dissolution fluid may also influence the dissolution results. The main objective of this work was to study the influence of the stirring rate conditions and of the dissolution apparatus in the diltiazem hydrochloride release from tablets. Diltiazem hydrochloride sustained-release (SR) tablets were tested and the following dissolution parameters were evaluated: t_10%, t_25%, t_50%, dissolution time, mean dissolution time (MDT), and dissolution efficiency (DE) at t₁₂₀, and at t₃₆₀. To analyze the release mechanism, several release models were tested, such as Higuchi, zero order, first order, Baker-Lonsdale, Hixson-Crowell, Weibull, and Korsmeyer-Peppas. The similarities between two in vitro dissolution profiles were assessed by the similarity factor f₂. The in vitro release kinetics of diltiazem hydrochloride sustained-release tablets were evaluated using the USP 2 (paddle) and USP 4 (flow-through) apparatus.     

Which Fullerene Is Appropriate to Host C20? A Molecular Modeling Study

Molecular mechanics (MM) and molecular dynamics (MD) study of fullerene complexes of the short-lived “smallest fullerene” C₂₀ with icosahedral C₆₀, C₈₀, C₁₄₀, C₁₈₀, and C₂₄₀ of I_h, I_h, I, I_h, I_h symmetry, respectively, using CVFF and ESFF forcefields revealed that the most stable complexes can be formed only if the intershell distance between fullerenes is similar to that in graphite or in experimentally observed buckyonions. The fullerenes C₁₄₀ and C₁₈₀ are the smallest suitable candidates to form such complexes with C₂₀. Similarly to the stabilization of short-lived cyclobutadiene or benzyne in hemicarcerands, C₂₀ is expected to be stabilized inside the C₁₄₀ and C₁₈₀ cages which would enable a deeper understanding of the highly nonplanar system of conjugated bonds of this exotic molecule.     

Probabilistic description of fatigue crack growth in polycrystalline solids

A stochastic model describing the crack evolution and scatter associated with the crack propagation process has been built on the basis of the discontinuous Markovian process. The evolution and scatter are identified in terms of constant probability curves whose equation is derived as In P_r(i) = B(e^KI₀ − e^Ki), i ≥ I₀, where i is the number of cycles, B and K are crack-length-dependent variables, P_r(i) is the probabiliity of the crack being at position r along the fracture surface after i cycles elapse and I₀ is the minimum number of cycles required for the crack to advance from one position on the fracture surface to the next. The validity of the model is established by comparing the crack growth curves generated for Al 2024-T3 at a specific loading condition with those experimentally obtained.     

Aggregation behavior of betaine-amphiphiles in the presence of polyvinylpyrrolidone

The aggregation behavior of zwitterionic surfactant dodecylbetaine (C₁₂BE) with and without polyvinylpyrrolidone (PVP) has been investigated by means of surface tension and steady-state fluorescence techniques. It shows that addition of PVP results in a decrease in the aggregation number of C₁₂BE micelle and “hydrophobic index” (I₁/I₃) of the probe (pyrene and pyrene-1-carboxaldehyde). PVP molecules are responsible for the phenomena: they bind to the surface of the micelle and prevent the rapid exchange of amphiphiles between micelles and water phase. There are two transition points in the plot of surface tension vs. concentration of C₁₂BE in the presence of PVP. The results indicate that the association takes place between PVP and C₁₂BE when the C₁₂BE concentration is above a critical aggregation concentration (CAC).     

Spectroscopic and electrochemical properties of poly(2,5 dimethyl aniline) films

UV–visible, IR and redox characteristics of electrochemically deposited poly(2,5 dimethyl aniline) films are affected by varying the monomer concentration (0.025, 0.05 and 0.1 M) and dopant anions in the electrolyte solution (HCl, HClO₄ and H₂SO₄). The optical spectra show the presence of reduced leucoemeraldine phase 320 nm and emeraldine salt phase 740 nm in HCl and HClO₄ while in case of H₂SO₄ media the pernigraniline phase is observed 540 nm. The magnitude of absorbance is highest in H₂SO₄>HCl>HClO₄. On the other hand, the selectivity in the formation of conducting phase is greater in HCl in comparison with HClO₄ and H₂SO₄. IR spectra of the film reveal a higher ratio for the relative intensities of the quinoid to benzenoid ring modes i.e. I₁₅₁₀/I₁₄₄₀ in case of films deposited in H₂SO₄. Cyclic voltammograms show the presence of a single redox couple in each case except for H₂SO₄ where an additional anodic peak is observed. However, the increase in current is highest in HCl>HClO₄>H₂SO₄ hence, the thickness of the films calculated for the cathodic peak are in accordance with the current.     

石墨烯/纳米减反结构复合透明导电薄膜的研究

石墨烯具有较高的透过率及良好的电导率, 作为透明导电薄膜具有潜在的应用价值。首先在石英基底上引入SiO₂纳米球阵列结构作为光学减反射层, 使石英基底可见光区光学透过率从93.2%增加到99.0%。然后利用常压化学气相沉积方法, 通过基底表面铜颗粒远程催化碳源, 直接在减反层上可控制备具有石墨烯/纳米减反结构的新型复合透明导电薄膜。通过去除SiO₂纳米球阵列结构形成反相复制的石墨烯空心球阵列结构, 且生长时间10 min时, 对应半高宽约40 cm^-1, I_2D/I_G = 2.31, I_D/I_G = 0.77, 证明在SiO₂纳米球阵列减反结构上制备了低缺陷且连续的全包覆少层石墨烯薄膜。引入SiO₂纳米球阵列减反结构后, 其在可见光区光学550 nm波长处的透过率平均提高了5.5%, 方块电阻相对无减反射层基底平均降低了20.09%。本研究方法避免了复杂的转移工序, 减少了对石墨烯的损失与破坏, 同时实现了高透光性及高导电性的功能协同, 在光伏器件、平板显示等领域展示出更大的应用前景。