用火花塞光纤传感器对爆震燃烧的试验研究

本文应用自行研制的火花塞光纤传感测量系统对 ＢＪ４９２Ｑ汽油机爆震燃烧进行测量和研究,同时用压力传感器、振动传感器进行对比,分析了爆震燃烧时火焰光辐射的变化情况。正常燃烧时,ＣＨ（４３１．５ｎｍ）、Ｃ２（５１６．５ｎｍ）、Ｈ２Ｏ＊（５８８ｎｍ自由基的光强曲线出现双峰值,着火延迟期内为自由基光辐射。爆震较强工况,只出现一个光强峰值,主要是碳粒子热辐射,峰值处出现剧烈波动,相位提前,无自由基的光辐射。压力曲线与光强曲线有很好的一致性。试验表明,火花塞光纤传感器抗干扰好,成本低,工作可靠,信号强,完全可用于爆震测量。     

用光纤燃烧传感器测量汽油机的燃烧时间参数的研究

本文介绍了一个光纤燃烧传感器及ＯＭＡ４光多通道分析仪组成的测量系统，用以测量汽油机燃烧火焰光谱。光谱分析结果再次证实了燃烧火焰中ＣＨ（４３１．５ｎｍ），Ｃ２（５１６．５ｎｍ），Ｈ２Ｏ（５８９ｎｍ）等自由基的特征光谱同Ｃ粒子的热辐射连续光谱叠加在一起，构成了火焰光谱。根据光谱曲线中Ｈ２Ｏ光强峰值变化，可以确定汽油机燃烧过程中重要的时间参数：着火延迟期和燃烧持续期。由于汽油机燃烧循环变动大，与单色仪和ＢＯＸＣＡＲ积分平均器组成的测量系统相比，光纤燃烧传感器＋ＯＭＡ４用光多通道分析仪系统测量汽油机燃烧火焰光谱，测量精度高，工作效率高。     

内燃机爆燃现象的分析

主要论述汽油机中燃料燃烧时中间产物ＯＨ（３０６．４ｎｍ）、ＣＨ（４３１．５ｎｍ）、Ｃ２（５１６．５ｎｍ）自由基的吸光度在正常燃烧和爆燃时的不同变化,在燃烧室中心区和终燃区的差别,并分析了发生爆燃时柴油机及快速压缩机型中的压力－时间变化关系,这有助于进一步弄清爆燃的机理。     

Ｃ臂ＣＴ成像在乏血供原发性肝癌诊疗中的临床应用

【摘要】 目的 探讨Ｃ臂 ＣＴ成像技术在乏血供原发性肝癌诊疗中的应用价值。方法 回顾性分析４３例乏血供原发性肝癌患者,使用数字减影血管造影（ＤＳＡ）系统,在ＴＡＣＥ前进行常规ＤＳＡ造影和Ｃ臂ＣＴ成像,比较ＴＡＣＥ治疗前ＣＴ／ＭＲＩ、ＤＳＡ造影和Ｃ臂 ＣＴ成像对肝脏肿瘤的检出率。 结果 ＴＡＣＥ后ＣＴ扫描共发现９７个乏血供肿瘤,ＣＴ／ＭＲＩ、ＤＳＡ造影、Ｃ臂 ＣＴ成像３种检查方法的检出率分别为７１．１％（６９／９７）、 ７８．４％（７６／９７）、 ８９．７％（８７／９７）（Ｐ ＜ ０．０５）。其中,３９个肿瘤直径 ＜ １０ ｍｍ,３种检查方法的检出率分别为６１．５％（２４／３９）、 ７６．９％（３０／３９）、 ８７．２％（３４／３９）（Ｐ ＜ ０．０５）; ５８个肿瘤直径≥ １０ ｍｍ,３种检查方法的检出率分别为７７．６％（４５／５８）、 ７９．３％（４６／５８）、 ８７．９％（５１／５８）（Ｐ ＞ ０．０５）。结论 Ｃ臂 ＣＴ成像能更准确、更敏感地检测出乏血供肝脏肿瘤,尤其对于直径 ＜ １０ ｍｍ的肿瘤,对原发性肝癌的治疗也有重要的临床价值。
     

大气式沼气灶的自制方法

１大气式沼气灶的结构图１所示为自制大气式沼气灶的结构图。为方便制作 ,我们采用最简单的结构。引射器为直管 ,一次进风口开在引射器两侧 ,喷嘴由一般的圆珠笔笔杆代替。２制作方法（１）喷嘴的制作选择１支废弃的普通圆珠笔笔杆 ,将其大头端有内丝的部分 (约１０ｍｍ左右 )截去 ;测量一下小头端 (尖头 )的内径 (一般在２．１～２．５ｍｍ之间 ) ,若其内径小于２．５ｍｍ ,则将其在砂纸上打磨 ,直至其内径约为２．５ｍｍ。这样 ,喷嘴就做好了。（２）引射器的制作找１根内径约２２ｍｍ ,长约１３０ｍｍ的硬质ＰＶＣ管 ,或同样尺寸的干燥无…     

爆燃燃烧对火焰辐射光变化的影响

应用火花塞光纤传感测量系统对BJ492Q汽油机爆燃燃烧进行测量和研究,分析了爆燃燃烧时火焰光辐射的变化情况。正常燃烧时,CH（431．5nm),C2(516.5nm),H2O(588nm)自由基的光强曲线出现双峰值,着火延迟期内自由基光辐射。爆燃较强工况时,只出现一个峰值,主要是碳粒子热辐射,峰值处出现剧烈波动,相位提前,无自由基的光辐射。试验表明,火花塞光纤传感器完全可用于爆燃测量。     

长江三峡地区构造地貌研究

长江三峡地区的层状地貌现象表明峡区地壳运动具有阶段性整体抬升的特点．根据三峡期夷平面的高程分布，获得本区自晚更新世（约１０万年）以来的平均抬升速率为１．５～５．０ｍｍ／ａ；根据长江一级阶地的高程计算，全新世（约１万年）以来的抬升速率为０．７～２．１ｍｍ／ａ．     

1．5t电弧炉微机自动控制的应用

１．５ｔ电弧炉微机自动控制的应用大连耐酸泵厂隗玉美，郝杰１设备改造前情况我厂铸钢车间１＃电弧炉是盖旋转、顶装料式电炉，公称容量１．５ｔ（实装３．０ｔ），炉壳直径φ２３００ｍｍ，石墨电极直径为φ２００ｍｍ。电极升降装置采用固定立柱式齿条传动，电极升降控...     

高功率微波消融治疗近大血管肝细胞癌３３例

【摘要】 目的 评价近大血管的肝细胞癌（ＨＣＣ）进行高功率微波消融治疗的疗效和安全性。方法 对 ３３例新发单发ＨＣＣ的患者经皮肝穿刺微波消融治疗，该３３病灶均为距离直径大于３ ｍｍ的血管０．５ ｃｍ以内，其中近门静脉支１７例，近肝静脉１２例，同时靠近的４例。所有患者均在Ｂ超引导下，采用单针或双针１００ Ｗ的高功率微波热凝２ ～　４ ｍｉｎ。并作短期随访，观察肿瘤消融疗效及并发症情况。结果 所有患者均安全完成微创消融手术。２例（６．１％）出现局部肿瘤进展，７例（２１．２％）出现新病灶（７／３３），５例复查ＣＴ可见局部血供异常，５例消融灶远端出现胆管轻度扩张，另１例术后６个月出现肝门部胆管狭窄伴肝内胆管扩张。结论 高功率微波治疗近血管的肿瘤疗效肯定，但有造成胆管损伤的风险。
     

增压导向式喷动流化床流动特性的试验研究

在内径２００ｍｍ，高３．５ｍ，６０°“Ｖ”形布风板的钢制试验装置上，采用密度为２４５０ｋｇ／ｍ３，粒径分别为（１．５～２．５）ｍｍ和（０．１～１．０）ｍｍ窄筛分玻璃珠，以及密度为２２００ｋｇ／ｍ３，粒径为（０．４５～６．０）ｍｍ的宽筛分溢流渣为物料，对各种压力下的导向式喷动流化床最小喷动流化速度、导向与环形区压降、中心喷泉高度以及颗粒循环量和气体旁路特性进行了试验研究。试验结果表明：最小喷动流化速度、导向与环形区压降以及中心喷泉高度与系统几何参数和操作参数密切相关，卷吸段气体射流的性质直接决定了颗粒循环量及其趋势，气体旁路的程度取决于卷吸段两股气流的相互作用。文章中用修正的弗劳德数归纳了中心喷泉高度试验关联式。     

Influence of cetane number improver on performance and emissions of a common-rail diesel engine fueled with biodiesel-methanol blend

In this paper, the effect of cetane number (CN) improver on performance and emissions, including particulate number concentration and size distribution, of a turbocharged, common-rail diesel engine fueled with biodiesel-methanol were studied. Two volume fractions (0.3% and 0.6%) of CN improver were added to BM30 (30% of methanol in the biodiesel-methanol blend) in the experiment. The results show that, compared with those of biodiesel-methanol blend, the peak value of cylinder pressure increases, the second peak of heat release rate decreases, the start of second heat release are advanced, and the fuel economy and thermal efficiency are improved when CN improver is added to biodiesel-methanol blend. Besides, CO and HC emissions decrease, NO_x emission varies little and smoke emissions increase slightly. Moreover, exhaust particles of BM30 mainly distribute in nano-size range. Furthermore, particle number concentration decreases and peak of size distribution profile shifts toward large size direction.     

Suppression of photo-induced dilation in cyanide treated hydrogenated amorphous silicon films

Effects of cyanide (CN) treatment with hydrogenated amorphous silicon (a-Si:H) films have been investigated. The decrease of ΔV/V was observed in cyanide treated a-Si:H films and the successive thermal annealing at 200°C after CN treatment induced the further reduction of the ΔV/V. XPS spectra show the indirect evidence that the cyanide species is present within 10 nm from the hydrogenated amorphous silicon surface. The results of CN treatment with a-Si:H solar cells are demonstrated.     

Investigating the origin of nuclei particles in GDI engine exhausts

While nuclei particles are found in vehicle emissions in low mass concentration, they are being studied since their number concentration may be high and they may contribute to the surface composition of larger particles and health effects associated with pollution. In this work, we obtain information on where particles emitted by an engine were formed/grown. This is done by comparing the measured particle charge fraction distributions to those calculated with Boltzmann theory for the different temperatures relevant to the combustion chamber, exhaust and sampling systems. We have applied this method to analyze the exhaust of a gasoline direct injection engine. Solid core particles with a size of 1–5 nm may be formed at high temperature in the combustion chamber and semivolatile species condense on their surface as the exhaust cools in the tail pipe, in low dilution conditions. Off-line measurements, using Surface Enhanced Raman Spectroscopy (SERS) show that the sampled particles have SERS spectra with typical D and G bands of disordered amorphous carbon similar to those measured for flame-generated nanoparticles.     

Experimental investigation of combustion characteristics and NOx formation of coal particles using laser induced breakdown spectroscopy

To study the mechanism of coal combustion and NO_x formation, the combustion of coal particles in different atmospheres (O₂/N₂, O₂/CO₂) with different O₂ concentrations was investigated using the CO₂ laser as a heat source. The spatial distribution of atoms and groups (e.g., H at 656.2 nm, O at 777.3 nm, CN at 388.3 nm) relating to the combustion flame were measured simultaneously using laser induced breakdown spectroscopy (LIBS). The residual energy was measured during the collection of LIBS spectra in the combustion process, which could be characterized the temperature profiles of combustion flame due to the positive correlation with temperature. The combustion stage could be clearly discriminated by the emission of H and CN, along with the flame temperature. The residual energy obtained in different atmospheres indicated that the impact of combustion atmosphere on flame temperature is greater in the char combustion stage rather than volatile combustion stage. It was determined from the temporal and spatial distribution of residual energy and CN intensity that a higher flame temperature leads to a higher concentration of CN. The correlation between the generation of CN and the NO_x formation was also investigated to show that the formation approaches of NO_x are similar in the O₂/CO₂ and O₂/N₂ atmospheres, while the fuel-N conversion paths are different between volatile combustion and char combustion stages. The measurement of temporal and spatial distributions of LIBS spectra with varying flame temperatures is significant in revealing the mechanism of coal-particle combustion and NO_x formation.     

Unexpected facilitation of the pyrolysis products of potassium ferrocyanide to the electrocatalytic activity of a PdO based palladium iron composite catalyst towards ethanol oxidation reaction (EOR)

It was found, for the first time, that the pyrolysis products of potassium ferrocyanide (K₄[Fe(CN)₆]) could significantly promote the electrocatalytic activity of the PdO based palladium iron composite catalyst towards ethanol oxidation reaction (EOR). In this work, huge carbon spheres (abbreviated as HCSs) were prepared firstly via a pyrolysis method using glucose and 1-butyl-3-methylimidazolium tetrafluoroborate as the starting materials. Secondly, PdO based palladium iron composites supported on HCSs (noted as PdO–Pd–Fe/HCSs) were successfully fabricated through a pyrolysis procedure employing PdO·H₂O, HCSs and K₄[Fe(CN)₆] as the initial materials. When preparing PdO–Pd–Fe/HCSs, four different amounts of K₄[Fe(CN)₆] were respectively added in the preparation system producing four kinds of samples. The sample prepared in the absence of K₄[Fe(CN)₆] was nominated as sample b-0. And the samples prepared in the presence of 5, 10 and 20 mg K₄[Fe(CN)₆] were, respectively, labeled as sample b-5, b-10 and b-20. It was indicated by the XRD and XPS patterns that the metallic Pd particles were the main crystalline materials of above four samples. SEM images of all synthesized samples substantially demonstrated that the added amount of K₄[Fe(CN)₆] was a pivotal factor which could significantly affect the morphologies of the prepared samples. For sample b-0, besides some nanoparticles with a size close to 30 nm, a larger number of pores were created on the surface of the HCSs producing a honeycomb-shaped surface. Interestingly, aniseed shaped particles, cauliflower-like particles and irregular particles with a diameter more than 150 nm were, respectively, anchored on the HCSs surface of sample b-5, b-10 and b-20. Most of all, as indicated by CV and CA measurements, all the samples prepared in the presence of K₄[Fe(CN)₆] delivered much better electrocatalytic activities towards EOR when compared to the sample prepared with no addition of K₄[Fe(CN)₆]. For example, in the CV curves, the peak current density of the peak appearing in the positive potential scanning (peak f) for EOR on sample b-10 was nearly 6.4 times greater than that on sample b-0 (16.6 mA cm^?2 vs. 2.6 mA cm^?2). The significantly decreased charge transfer resistance and the remarkably enlarged electrochemical surface area were analyzed to be the main reasons for sample b-10 to exhibit the best electrocatalytic performance among all prepared samples. In general, a novel electrocatalyst consisting of PdO, Pd and the pyrolysis products of K₄[Fe(CN)₆] for EOR was developed in this work, which, due to its very lower preparation cost and its satisfied electrocatalytic activity towards EOR, was very helpful to the development of Pd-based EOR electrocatalyst.     

Novel ReS2/g-C3N4 heterojunction photocatalyst formed by electrostatic self-assembly with increased H2 production

Binary heterostructures (named as CN@Re) composed of ReS₂ nanospheres and g-C₃N₄ nanosheets are constructed by electrostatic self-assembly method. The ReS₂ nanospheres were prepared by hydrothermal method and the g-C₃N₄ nanosheets were treated with surface charge modification. Hydrogen production efficiency of modified CN and CN@Re nanostructures was evaluated in a simulated solar environment. To our surprise, CN5@Re5% exhibits the highest H₂ production up to 1823 μmol g^?1h^?1 of CN5@Rey, which is 3.2 times as high as CN. The improvement of the photocatalytic hydrogen production efficiency of modified CN is attributed to its interaction with the hole sacrificing agent lactic acid, while the improvement of the photocatalytic activity of CN@Re nanostructure is attributed to the efficient electron transfer efficiency between CN and ReS₂ and the enhanced light absorption capacity brought by ReS₂. In addition, the photocatalytic stability of CN5@Re5% has been studied, which can maintain a stable rate of hydrogen production over four cycles. The apparent quantum efficiency is as high as 4.10% at 365 nm and 2.82% at 420 nm.     

Surface-induced thermal decomposition of [Ru(dcbpyH)2-(CN)2] on nanocrystalline TiO2 surfaces: Temperature-dependent infrared spectroscopy and two-dimensional correlation analysis

Thermal degradation mechanism of the self-assembled thin films of [Ru(dcbpyH)₂-(CN)₂] (Ruthenium 505, R505) anchoring on TiO₂ surfaces via its carboxylate group has been examined by temperature-dependent diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy. The CN stretching bands of R505 at 2000-2100 cm⁻¹ appeared to change drastically at ≈140 °C on TiO₂ surfaces, whereas a major CN peak at ∼2090 cm⁻¹ disappeared at a much higher temperature above ≈250 °C in their solid states. Two-dimensional (2D) correlation analysis was introduced to explain the thermal desorption behaviors of the Ruthenium dye. Multiple peaks of the CN stretching vibrations are more clearly resolved in the 2D correlation analysis. More complicated features in the CN stretching vibrational spectra on TiO₂ than those of the solid states suggest a substantial interaction of the CN groups with the TiO₂ surfaces.     

Preparation of porous C doped g-C3N4 nanosheets controlled by acetamide for photocatalytic H2 evolution

Photocatalytic production H₂ of splitting water is an important branch of the application of photocatalytic materials. In this paper, porous C doped carbon nitride was successfully synthesized by calcining urea and acetamide at high temperature, and then analyzed by various characterization methods. XRD and FT-IR spectra show that the crystal structure of carbon nitride modified by acetamide are similar to bulk carbon nitride. SEM and TEM spectra show that the morphology and structure of carbon nitride and carbon nitride was modified by acetamide, which presents a porous nanosheets structure. XPS and EDS show that the content of carbon element in carbon nitride modified by acetamide increased significantly. The PL spectrum is obviously red shift, and the light absorption range is obviously enlarged, which is consistent with the absorption edge of UV–vis Spectrum. The BET of the optimized sample CN2-6 is 122.79 m²g^-1, which is 3.04 times higher than that of bulk carbon nitride CN1 (40.456 m²g^-1). In addition, the hydrogen production of CN2-6 is 13169.04 μmol/g/h under 300 W Xenon lamp, which is 14.95 times more than CN1 (880.82 μmol/g/h) hydrogen production rate. When the light source is a 10 W LED lamp, the apparent quantum efficiency (AQE) of sample CN2-6 reaches the maximum (2.91) under the wavelengths of 430 nm, which is 1.27 times more than CN1 under the same conditions. Meanwhile, prepared samples have excellent stability and durability under visible light.     

轻型柴油车尾气烟羽中颗粒数量与粒径分布

测量了轻型柴油车在高怠速和低怠速运转的条件下，其尾气烟羽中粒径范围在15nm到30μm的颗粒数量和粒径的分布。利用SMPS和APS测量装置测量尾气烟羽中心线和环境背景条件下的颗粒排放。测量结果表明，测试的柴油车在高怠速运转的条件下会排放出更多的颗粒。然而，在两种怠速条件下，总的颗粒数量浓度由于沉降的作用会随着远离排气管的距离而减少。测量结果还表明，柴油车排放的颗粒主要是粒径小于700nm的颗粒，这些细颗粒比粗颗粒更易长期悬浮于大气中，从而引发局部的颗粒物污染问题。