传输核心汇聚机房工艺布局规划研究

本文通过理论分析与实地测试,探究了当前传输核心汇聚机房普遍存在的局部温度过高问题,分析了造成该问题的主要原因,并提出了降低机房局部温度过高的工艺布局规划方法.     

All-Solid-State Rechargeable Air Batteries Using Dihydroxybenzoquinone and Its Polymer as the Negative Electrode

A proof-of-concept study was conducted on an all-solid-state rechargeable air battery (SSAB) using redox-active 2,5-dihydroxy-1,4-benzoquinone (DHBQ) and its polymer (PDBM) and a proton-conductive polymer (Nafion). DHBQ functioned well in the redox reaction with the solid Nafion ionomer at 0.47 and 0.57 V vs. RHE, similar to that in acid aqueous solution. The resulting air battery exhibited an open circuit voltage of 0.80 V and a discharge capacity of 29.7 mAh g_DHBQ⁻¹ at a constant current density (1 mA cm⁻²). With PDBM, the discharge capacity was much higher, 176.1 mAh g_PDBM⁻¹, because of the improved utilization of the redox-active moieties. In the rate characteristics of the SSAB-PDBM, the coulombic efficiency was 84 % at 4 C, which decreased to 66 % at 101 C. In a charge/discharge cycle test, the capacity remaining after 30 cycles was 44 %, which was able to be significantly improved, to 78 %, by tuning the Nafion composition in the negative electrode.     

空气在二甲基硅油和液压油中的溶解度

对于诸多工程运用场合, 获得空气在硅油以及液压油中溶解度可靠的数据至关重要. 针对已有测量装置及方法的不足, 建立了一种基于理想气体状态方程来确定气体溶解量的新型精密活塞式装置. 获得了温度为293.2及353.2 K, 压力在0-350 kPa范围内, 空气在500cSt 二甲基硅油中的本生溶解度表达式. 测量了298.2 K时20cSt二甲基硅油及国产32#抗磨液压油在多种气相压力下的本生溶解度. 精度及可靠性分析表明实验数据的误差范围为6%. 本生溶解度与气相压力呈较好的线性关系, 以摩尔分数表示的溶解度与压力呈非线性关系, 但可用Krichevsky-Ilinskaya方程拟合. 发现空气在相对分子质量差异很大的两种二甲基硅油中的本生溶解度很接近, 由此提出, 对于小分子的非极性溶质在聚合物溶剂中的溶解度, 用聚合物单体的摩尔数而不是聚合物分子摩尔数来表示摩尔浓度更有利于实验数据的外推和工程应用. 对于相对分子质量差别较大或无法确定相对分子质量的溶剂, 工程应用中适宜采用本生溶解度.     

基于单片机的电动空气伞控制系统的设计

针对传统雨伞体积大、质量大、收起时滴水弄湿地板的问题,一种靠电动机驱动转子带动风叶旋转形成空气屏障来避雨"空气伞"便应运而生了.本文在实物的设计下提出一种基于单片机来设计电动空气伞的控制系统,通过此控制系统实现空气雨伞的无极调速以及能反馈给用户实时的电量情况.这种经典控制系统具有很强的稳定性以及快速性,通过其硬件和软件的设计能实现空气伞预期的功能,为空气伞的后续设计打下了坚实的基础.     

Influence of turbulence on train noise

The subject of this paper is the long distance propagation of train noise. The sound exposure level of train noise L_AE was measured. To describe the results of measurements, a semi-analytical model was used. It takes into account the wave-front divergence, air absorption, ground effect, and the turbulence destroying the coherent nature of the ground effect. The model contains three adjustable parameters that must be estimated at the site. To verify the model, we performed measurements of L_AE at the distance D = 450 m from the train track center. The difference between the calculated and measured mean values of L_AE equals 1.3 dB.     

某型压缩空气站自动监控报警器系统设计

针对某型压缩空气站日常维护保障需求,设计开发了一款压缩空气站自动监控报警器。该自动监控报警器系统通过信号隔离变送器,实时采集滑油压力信号、水温油温信号、转速信号、压缩空气压力等信号,由系统微型控制器模块进行ADC采集、转换并处理。系统微型控制器采用STC12单片机,运行嵌入式控制程序,对采集到的各类信号进行显示、阈值判断和报警等处理。该自动监控报警器能实时监控压缩空气站的多个关键运行参数并自动报警,有利于压缩空气站的安全运行与操作。     

Detection of cocaine in the airborne particles of the Italian cities Rome and Taranto

Cocaine was first detected in the air of two Italian cities, Rome and Taranto, where it reached concentrations sometimes exceeding 100 pg/m(3), by HRGC-MS analysis of carbonaceous aerosol samples. By contrast, the drug was virtually absent in Algiers (Algeria). In Italy, atmospheric concentrations of cocaine were, on average, similar to those of other toxic pollutants like polychlorobiphenyls or nitrated polynuclear aromatic hydrocarbons, and higher than those of polychlorodibenzo-p-dioxins/polychlorodibenzofurans. The cocaine concentrations seemed to correlate with regional consumption of the drug in Rome and Taranto. By contrast, it correlated neither with nicotine or caffeine, nor with benzo[a]pyrene, the sole organic compound associated with aerosols that is quoted according to Italian legislation.     

The certification of a nominal 20 μmol/mol H<Subscript>2</Subscript>S/N<Subscript>2</Subscript> standard reference material using two independent methods

To support federal, state and local regulations on the amount of hydrogen sulfide (H(2)S) released into the atmosphere, the National Institute of Standards and Technology (NIST) has certified standard reference material (SRM) 2731 Hydrogen Sulfide in Nitrogen (nominal amount-of-substance fraction 20 micromol/mol H(2)S). Since it was first produced and certified in 1989, NIST has certified four separate lots of this SRM. In each case, the value assignment of the lot concentration was accomplished by comparison to a permeation tube-generated calibration curve. For the certification of the new lot, two independent methods were used to value-assign the concentration. In addition to the permeation tube method, a second method involving the dynamic dilution of a high-concentration gravimetrically prepared primary standard mixture containing H(2)S/N(2) was also used. Agreement between the two methods was 0.10% and the total uncertainty assigned to the lot concentration was 1.35% (relative).     

Laboratory simulation of Hg<Superscript>0</Superscript> emissions from a snowpack

Snow surfaces play an important role in the biogeochemical cycle of mercury in high-latitude regions. Snowpacks act both as sources and sinks for gaseous compounds. Surprisingly, the roles of each environmental parameter that can govern the air–surface exchange over snow are not well understood owing to the lack of systematic studies. A laboratory system called the laboratory flux measurement system was used to study the emission of gaseous elemental mercury from a natural snowpack under controlled conditions. The first results from three snowpacks originating from alpine, urban and polar areas are presented. Consistent with observations in the field, we were able to reproduce gaseous mercury emissions and showed that they are mainly driven by solar radiation and especially UV-B radiation. From these laboratory experiments, we derived kinetic constants which show that divalent mercury can have a short natural lifetime of about 4–6 h in snow.     

Synthesis, characterization, thermal stability and electrochemical properties of poly-4-[(2-methylphenyl)iminomethyl]phenol

In this study, the reaction conditions of poly-4-[(2-methylphenyl)iminomethyl]phenol (P-2-MPIMP) were studied by using oxidants such as air O₂, H₂O₂ and NaOCl in an aqueous alkaline medium between 50 and 90 °C. The structures of the synthesized monomer and polymer were confirmed by FT-IR, UV-vis, NMR and elemental analysis. The characterization was made by TG-DTA, size exclusion chromatography (SEC) and solubility tests. At the optimum reaction conditions, the yield of poly-4-[(2-methylphenyl)iminomethyl]phenol (P-2-MPIMP) was found to be 20% (for air O₂ oxidant), 33% (for H₂O₂ oxidant), and 74% (for NaOCl oxidant). According to the SEC analysis, the number-average molecular weight (M_n), weight-average molecular weight (M_w) and polydispersity index (PDI) values of P-2-MPIMP were found to be 3300, 4100 g mol⁻¹ and 1.242, using H₂O₂, and 4550, 5150 g mol⁻¹and 1.132, using air O₂ and 5300, 5850 g mol⁻¹ and 1.104, using NaOCl, respectively. According to TG analysis, the weight losses of 4-[(2-methylphenyl)iminomethyl]phenol (2-MPIMP) and P-2-MPIMP were found to be between 75.29% and 48.17% at 1000 °C, respectively. P-2-MPIMP was shown to have a higher stability against thermal decomposition. Also, electrical conductivity of the P-2-MPIMP was measured, showing that the polymer is a typical semiconductor. Electrochemically, the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO) and electrochemical energy gaps ( of 2-MPIMP and P-2-MPIMP were found to be −6.01, −6.03; −2.63, −2.82; 3.38 and 3.21 eV, respectively. According to UV-vis measurements, the optical band gap (E_g) of 2-MPIMP and P-2-MPIMP was found to be 3.40 and 2.97 eV, respectively.