微结构换能元的低能化设计与性能研究

随着科技的不断向前发展,当前世界范围内弹药技术取得了极大的突破。 MEMS火工品由于其在实际应用中所具有的一系列优势被世界各国所重视。在这样的情况下,为了使得MEMS火工品在应用时对于能量利用率提出的严格要求得到有效满足。文章对MEMS技术进行了详细分析,并且结合换能元技术设置了8种不同桥区中心角度的微型薄膜换能元。为了对该换能元的实际应用表现进行查看,对各类换能元样品的一些参数进行了详细测试,并且对电容在处于放电状态当中的发火性质进行了研究。最终发现微型薄膜换能元在应用时可以通过桥区面积的合理缩小使得MEMS火工品在实际应用的过程当中全面提高对能源的利用率,除此之外,经过试验发现当V型桥区的中心角度处于50度到90度这一范围之内时薄膜换能元的电压可以降到最低的程度。

避免人力资源管理中的低能化措施——评迪尔伯特原则

文章评述了迪尔伯特原则中所描述的低能式管理的企业,以及人力资源管理在这样的企业所体现出来的低能化特征,进而浅析了企业人力资源管理过程中如何避免低能化。

低能电子离化氢原子的三重微分截面

运用修正后的BBK理论计算了入射能近阈值的情况下 (E0 =30、2 5、2 0、17.6和 15 .6eV) ,共面等能、两个出射电子相对角取不同固定值时电子入射离化氢原子的三重微分截面 (TDCS) ,所得结果与实验进行比较 ,符合较好。指出 :对 3C波函数进行索末菲参量的修正是成功的 ,这一修正使得BBK模型也能对入射能近阈值的低能 (e,2e)过程给出很好的描述。

低能电子离化He原子(e,2e)反应中的动力学屏蔽

在三体索末菲参量修正的基础上，进一步对（ｅ，２ｅ）反应的末态Ｈｅ＋中核外电子的有效屏蔽给出修正．这种修正反映了末态四粒子间的动力学屏蔽．并用修正后的索末菲参量计算了入射能量为５０ｅＶ时，共面不对称几何条件下电子离化Ｈｅ原子的三重微分截面．所得结果与ｃｏｎｖｅｒｇｅｎｔｃｌｏｓｅｃｏｕｐｌｉｎｇ理论结果及最新绝对测量的实验数据进行比较，发现当敲出电子能量为１０ｅＶ时，理论曲线更接近实验数据．

基于电热特性分析的微桥膜设计

为实现MEMS技术加工的微桥膜低能化,设计不同结构和材料的桥膜,仿真研究桥膜电流密度、温度的变化过程;通过研究方形桥区对角线的电热特性曲线,以解决电流与H型微桥膜材料的匹配问题。结果表明:微桥膜两端输入电流为500A时,H型桥膜桥区温度分布最均匀;相比铜微桥膜,金桥膜达到熔点所需的时间短,但是平均升温速率低;铜微桥膜的熔化面积大、分布更均匀。在300~700A输入电流范围内,对于铜、金、铝H型微桥膜,输入电流依次为500A、450A、400A时起爆可以提高它们的能量利用率。

Paul阱中基态低能多离化Fe^(n+)(n=1—3)离子的存储及反应特性

利用垂直交叉的激光束在Paul阱中溅射固体铸铁 (FeC)靶 ,产生了低能多电荷铁离子Fen + (n =1— 3 ) ,得到了Fe3 + 离子在本底气压为 3 0× 10 - 7Pa下的衰减速率 (0 96s- 1)以及在 1 3× 10 - 5 Pa下和中性气体分子N2

Multi-effect distillation system for seawater desalination driven by tidal energy and low grade energy

A multi-effect distillation technology for seawater desalination driven by tidal energy and low grade energy is presented.In the system,tidal energy is utilized to supply power instead of coventional electric pumps during the operation,resulting in the decrease of dependence on steady electric power supply and a reduction in the running costs.According to the technological principle,a testing unit is designed and built.The effects of the feed seawater temperature and the heat source temperature on the unit performance are tested and analyzed.The experimental results show that the fresh water output is 27 kg/h when the heating water temperature is 65 ℃ and the absolute pressure is 25 kPa.The experimental and theoretical analysis results indicate that the appropriate heating water temperature is a key factor in ensuring the steady operation of the system.

Anti-cracking mechanism of diatomite asphalt and diatomite asphalt mixture at low temperature

A kind of neat asphalt and three kinds of diatomite asphalt are tested using differential scanning calorimetry（DSC）. The anti-cracking mechanism of diatomite asphalt is analyzed by DSC and the thermal stress restrained specimen test（TSRST） of the asphalt mixtures. The results show that the low temperature performance of diatomite asphalt is better than that of neat asphalt. The glass transition temperature can reflect the low temperature performance of the diatomite asphalt better and has a good relationship with breaking temperatures. Besides, the TSRST, the bending test, the compressing test and the contraction coefficient test are used to study the low temperature performance of the diatomite asphalt mixture. The results prove that the low temperature performance of the diatomite asphalt mixture is better than that of the neat asphalt mixture. The critical bending strain energy density and the compressing strain energy density of the diatomite asphalt mixture are greater than those of the neat asphalt mixture. After adding diatomite to the asphalt mixture, the contraction coefficient is reduced. Based on the above results, the anti-cracking mechanism of the diatomite asphalt mixture is analyzed from the angle of contraction performance and breaking energy.

当前高校公共艺术教育的四大问题

当前高校公共艺术教育发展面临很多问题，如对公共艺术教育教学的重要性认识不足，尚未形成科学合理的课程体系，师资队伍不均衡、结构不合理等。总结概括为四大问题：边缘化、表面化、平庸化和低能化。

Calculation of Apparent Activation Energy of Coal Oxidation at Low Temperatures by Measuring CO Yield

By analyzing previous studies on activation energy of coal oxidation at low temperatures, a theoretical calculation model of apparent activation energy is established. Yield of CO is measured by using the characteristic detector of coal oxidation at 30-90 ℃. The impact of parameters, such as airflow and particle size, on activation energies is analyzed. Finally, agreement was obtained between activation energies and the dynamic oxygen absorbed in order to test the accuracy of the model. The results show that： 1） a positive exponential relation between concentration of CO and temperature in the process of the experiment is obtained： increases are almost identical and the initial CO is low; 2） the apparent activation energies increase gradually with the sizes of particle at the same airflow, but the gradients increase at a decreasing rate; 3） the apparent activation energies increase linearly with airflow. For the five coal particles, the differences among the energies are relatively high when the airflow was low, but the differences were low when the airflow was high; 4） the optimum sizes of particle, 0.125-0.25 ram, and the optimum volume of airflow, 100 mL/min, are determined from the model; 5） the apparent activation energies decrease with an increase in oxygen absorbed. A negative exponential relation between the two is obtained,

Energies and Transition Rates of Low-Lying Excited States for Beryllium

Low lying excited states of beryllium are calculated with multiconfiguration interaction method. The relativisitic corrections and mass polarization are included. The oscillator strength and radiation rates are also calculated. Our results are in good agreement with other theoretical data.

Mn/beta and Mn/ZSM-5 for the low-temperature selective catalytic reduction of NO with ammonia: Effect of manganese precursors

Two series of Mn/beta and Mn/ZSM‐5catalysts were prepared to study the influence of how different Mn precursors,introduced to the respective parent zeolites by wet impregnation,affected the selective catalytic reduction(SCR)of NO by NH3across a low reaction temperature window of50–350°C.In this study,the catalysts were characterized using N2adsorption/desorption,X‐ray diffraction,X‐ray fluorescence,H2temperature‐programmed reduction,NH3temperature‐programmed desorption and X‐ray photoelectron spectroscopy.As the manganese chloride precursor only partially decomposed this primarily resulted in the formation of MnCl2in addition to the presence of low levels of crystalline Mn3O4,which resulted in poor catalytic performance.However,the manganese nitrate precursor formed crystalline MnO2as the major phase in addition to a minor presence of unconverted Mn‐nitrate.Furthermore,manganese acetate resulted principally in a mixture of amorphous Mn2O3and MnO2,and crystalline Mn3O4.From all the catalysts screened,the test performance data showed Mn/beta‐Ac to exhibit the highest NO conversion(97.5%)at240°C,which remained>90%across a temperature window of220–350°C.The excellent catalytic performance was ascribed to the enrichment of highly dispersed MnOx(Mn2O3and MnO2)species that act as the active phase in the NH3‐SCR process.Furthermore,together with a suitable amount of weakly acidic centers,higher concentration of surface manganese and a greater presence of surface labile oxygen groups,SCR performance was collectively enhanced at low temperature.?2018,Dalian Institute of Chemical Physics,Chinese Academy of Sciences.Published by Elsevier B.V.All rights reserved.

On Advanced Control Methods toward Power Capture and Load Mitigation in Wind Turbines

This article provides a survey of recently emerged methods for wind turbine control. Multivariate control approaches to the optimization of power capture and the reduction of loads in components under time-varying turbulent wind fields have been under extensive investigation in recent years. We divide the related research activities into three categories： modeling and dynamics of wind turbines, active control of wind turbines, and passive control of wind turbines. Regarding turbine dynamics, we discuss the physical fundamentals and present the aeroelastic analysis tools. Regarding active control, we review pitch control, torque control, and yaw control strategies encompassing mathematical formulations as well as their applications toward different objectives. Our survey mostly focuses on blade pitch control, which is considered one of the key elements in facilitating load reduction while maintaining power capture performance. Regarding passive control, we review techniques such as tuned mass dampers, smart rotors, and microtabs. Possible future directions are suggested.

Effective Approach to Elevate the Intelligence of Management Decision System

Based on the sticking point of the low intelligence of the existing management decision system,this paper puts forward the idea of enriching and refining the knowledge of the system and endowing it with the ability to learn by means of adopting three types of heterogeneous knowledge representation and knowledge management measures.At length,this paper outlines the basic framework of an intelligence system for the sake of management decision problem.

Influence of Electrolyte on ESR of Medium Voltage Wet Tantalum Capacitors

In this paper, the influence of working electrolyte on high-frequency electrical performance of wet tantalum capacitors is studied. Emphasis is especially put on the study of the contribution of depolariser in reducing Equivalent Series Resistance(ESR). According to the theory of depolarization in electrochemistry and the theory of cathode capacitance of electrolytic capacitor, different kinds of depolarisers are added separately into the foregone electrolyte. Then capacitors are assembled with tantalum cores dipped with the compounded electrolytes. The best depolariser and its concentration in the whole electrolyte could be selected according to the test results of the capacitance and ESR of the capacitors. The results of our experiment show that depolariser Fe 2(SO 4) 3 used in working electrolyte of 100 V/100 μF wet tantalum capacitors can help to obtain lower ESR and higher capacitance at frequency from 0.1 kHz to 100 kHz.

Three-Dimensional Cu-Ni Composite Superamphiphobic Surface via Electrodeposition and Fluorosilane Modification

A superamphiphobic(SAP)surface was fabricated by electrodepositing Cu-Ni micro-nano particles on aluminum substrate and modifying via 1 H,1 H,2 H,2 Hperfluorodecyltrimethoxysilane.Scanning electron microscopy,X-ray diffraction,energydispersive X-ray spectroscopy,and Fourier-transform infrared spectroscopy were employed to investigate the morphology and chemical composition.The results showed that the SAP surface had three-dimensional micro-nano structures and exhibited a maximum water contact angle of 160.0°,oil contact angle of 151.6°,a minimum water slide angle of 0°and oil slide angle of 9°.The mechanical strength and chemical stability of the SAP surface were tested further.The experimental results showed that the SAP surface presented excellent resistance to wear,prominent acid-resistance and alkali-resistance,self-cleaning and anti-fouling properties.

The Role of Hydrogen Bond in Catalytic Triad of Serine Proteases

In order to investigate the origin of catalytic power for serine proteases,the role of the hydrogen bond in the catalytic triad was studied in the proteolysis process of the peptides chymotrypsin inhibitor 2(CI2),MCTI-A,and a hexapeptide(SUB),respectively.We first calculated the free energy profile of the proton transfer between His and Asp residues of the catalytic triad in the enzyme-substrate state and transition state by employing QM/MM molecular dynamics simulations.The results show that a low-barrier hydrogen bond(LBHB)only forms in the transition state of the acylation of CI2,while it is a normal hydrogen bond in the acylation of MCTI-A or SUB.In addition,the change of the hydrogen bond strength is much larger in CI2 and SUB systems than in MCTI-A system,which decreases the acylation energy barrier significantly for CI2 and SUB.Clearly,a LBHB formed in the transition state region helps accelerate the acylation reaction.But to our surprise,a normal hydrogen bond can also help to decrease the energy barrier.The key to reducing the reaction barrier is the increment of hydrogen bond strength in the transition state state,whether it is a LBHB or not.Our studies cast new light on the role of the hydrogen bond in the catalytic triad,and help to understand the catalytic triad of serine proteases.

Effects of various fillers on sintering, microstructures and properties of Ca-Ba-Al-B-Si-O glass/ceramic composites

Low-temperature sintering and properties of LTCC （low temperature co-fired ceramics） materials based on CaO-BaO-Al2O3-B2O3-SiO2 glass and various fillers such as Al2O3, silica glass, christobalite, AlN, ZrO2, MgO-SiO2, TiO2 were investigated. The results show that densification, crystallization, microstructures and dielectric properties of the composites are found to strongly depend on the type of filler. The densification process of glass/ceramic composites with various fillers is mainly from 600 ℃ to 925 ℃, and the initial compacting temperature of samples is 600 ℃. The initial rapid densification of samples starts at its glass softening temperature. LTCC compositions containing Al2O3, silica glass, AlN and MgO-SiO2 fillers start to have the crystallization peaks at 890, 903, 869 and 844 ℃, respectively. The crystallization peaks are believed as correlated to the crystallization of CaAl2SiO8, β-SiO2, Ca2Al2SiO7 and β-SiO2. The composite ceramic with Al2O3, silica glass and TiO2 ceramic have a better dense structure and better smooth fracture surface. Sample for Al2O3 has the lowest dielectric loss tanδ value of 0.00091, whereas the sample for MgO.SiO, has the highest dielectric loss tanδ value of 0.02576. The sample for TiO2 has the highest dielectric constant value of 14.46, whereas the sample for AIN has the lowest dielectric constant value of 4.61.

Interaction Mechanism of Nano-silicon Dioxide Modified by Poly（amidoamine） Dendrimers

To gain insight into the attachment of =Si^＋ （SC） ion （regarded as guest） to the lowest generation, NH2-terminated poly（amidoamine） （PAMAM） dendrimers （regarded as host） in the liquid phase, density functional theory is used to investigate the structures and energetics of the host-guest complex. The effect of solvent on the structures and energetics is also investigated. Various initial configurations of the ion bound to PAMAM are tested, and two stable conformers are found, i.e, types A （=Si^＋ is bound to the amine site） and C （=Si^＋ is bound to the amide site）. Types A and C are the most stable due to the chemical bond formations of Si-N° （amine nitrogen atoms） and Si-O, respectively. The IR spectra for the lowest energy conformers are thoroughly analyzed and compared with the available experimental data.

Hydration and Mechanical Properties of Portland Cement Blended with Low-CaO Steel Slag

The hydration and mechanical properties of Portland cement blended with low-CaO steel slag were studied and reported. The steel slag was used to replace cement up to 30% and then blended cement powder, paste and mortar samples prepared for the experiment. The quantitative analysis of XRD shows that ettringite formation is greatly reduced by incorporation of steel slag but there was a relatively low reduction of portlandite. Thermal analysis by TG shows that slag injection reduced portlandite content in the cement by at least 50%. Generally, the slag cement pastes required less water to form a workable paste compared to the reference cement, reducing as the slag content was increased. However, the setting times were higher than the reference. The permeability of the blended cement samples were lower than the control. The incorporation of 5% slag could not have an effect on the compressive strength of the concrete. The results confirmed that whilst cements with up to 15% slag content satisfied the strength requirements of class 42.5 N and those containing 20%-30% produce Class 32.5R cement.