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1.
助燃法在燃烧热测定实验中的实践与应用 总被引：1，自引：0，他引：1
用计算机自动控制或手控操作测定燃烧热实验时,在点火丝和药片之间滴一滴非挥发性机油予以助燃,确保了实验点火的100%成功,实验时间由4.0~5.0 h减少至2.0~2.5 h,充氧压力由20 atm可降至10 atm,实验相对误差在2%以下,远远小于5%的实验要求,且完美解决了该实验因点火失败而带来的费时费力操作烦恼.通过在实验教学中反复应用,效果很好,值得同行借鉴和推广. 相似文献
2.
This work investigates the effects of exhaust gas recirculation (EGR) and operation parameters including engine speed, equivalence ratio, coolant-out temperature, and intake charge temperature on the basic characteristics of a single-cylinder homogeneous charge compression ignition (HCCI) engine powered with reformulated iso-octane fuels. The running range of iso-octane HCCI engine can be expanded to lower temperature and more load by adding di-tertiary butyl peroxide (DTBP) in the fuel. The combustion timing advances with the increase of DTBP concentrations, coolant temperature and equivalence ratio. The effects of EGR on the combustion and emissions are remarkable when the EGR rate is higher than 25%, and the combustion phase is sharply postponed and the UHC and CO emissions deteriorate. The intake charge temperature has a moderate effect on combustion and emissions when it is lower than 35°C; but the combustion timing advances, the combustion duration shortens, and sometimes it leads to knock combustion when the intake charge temperature increases to above 35°C. 相似文献
3.
In 1972 ,KimandTakahashi[1] observedagiantsaturatedmagneticfluxdensity (Bs=2 .5 8T)whichwas 17%strongerthanthatofpureiron .BelievingthattheFe NfilmwasapolycrystallinemixtureofFeandα″ Fe16 N2 ,theydeducedthattheBsofα″ Fe16 N2 wouldbe2 .83Tfromthevolumeratioofα″ Fe16 N2 inthefilm .Sincethelargesaturatedfluxdensityisofimportance ,boththeoreticallyandfromthepointofviewofpracticalapplications,manyresearchershavemadegreateffortsandusedavarietyofmethodstosynthesizeα″ Fe16 N2 intobulkmat… 相似文献
4.
Jun-chun ZHANG Le-ming CHENG Cheng-hang ZHENG Zhong-yang LUO Ming-jiang NI 《浙江大学学报(A卷英文版)》2013,14(9):671-678
In this study, a porous inserted regenerative thermal oxidizer （PRTO） system was developed for a 125 kW industrial copper-melting furnace, due to its advantages of low NOr emissions and high radiant efficiency. Zirconium dioxide （ZrOz） ce- ramic foams were placed into the combustion zone of a regenerative thermal oxidizer （RTO）. Different performance characteris- tics of the RTO and PRTO systems, including pressure drop, temperature distribution, emissions, and energy efficiency, were evaluated to study the effects of the porous inserts on non-premixed CH4 combustion. It was found that the PRTO system achieved a significant reduction in the NOx emission level and a fuel saving of approximately 30% compared to the RTO system. It is most suitable for a lean combustion process at an equivalence ratio 〈0.4 with NOx and CO emission levels within 0.002%~）.003% and 0.001%q3.002%, respectively. 相似文献
5.
本文的目的是研究半多孔内皮细胞的包膜(SPEUs)的效应 以PTMEG1000为基础的SPEU的多孔性为51.58%(±5.86%) 与天然脉管相比较,例如与一头6个月小牛胸部的上部下来的主动脉大血管相比较,SPEU的拉伸强度是足够强的 脉管的典型脉动压力服从静脉管压力(1.5～2%Δd/d),此压力小于动脉管压力(9～15%Δd/d) 在种植EC之前,观察了在SPEUs上培育的人皮的成纤维细胞(HDF) SPEU的DNA数量与HDF在一天之内种植;有71.9%(±11.01%)细胞被种植在SPEUs上 LDH试验表明:在有控制的和实验群数据之间没有显著的差别,说明没有细胞毒素 因此,EC在SPRUs上具有良好的粘附性,这是所期望的,而应用胶原实现了将EC种植在半微孔的SPEUs上的表面改善 相似文献
6.
山苍子油多段连续减压精馏提取柠檬醛工艺 总被引：1，自引：0，他引：1
研究多段连续减压精馏山苍子油提取柠檬醛的生产工艺,通过正交实验分析不同操作条件（回流比、塔顶温度和塔釜温度）下所得柠檬醛产品的浓度与得率,得出了该实验流程精馏塔系统的塔顶温度和回流比的控制对产品纯度有显著影响.维持较高的系统绝压为666.612～2 666.447Pa时,阻聚剂和抗氧化剂的添加量最少应达0.3%,可获得该实验系统提取柠檬醛的较佳工艺条件.基于该文原料油生产的柠檬醛纯度最高达95%,得率65%. 相似文献
7.
1 Ｉｎｔｒｏｄｕｃｔｉｏｎ ＩｒｏｎａｌｕｍｉｎｉｄｅｓｂａｓｅｄｏｎＦｅ3 Ａｌｈａｖｅｍａｎｙａｄｖａｎｔａｇｅｓｆｏｒｓｔｒｕｃｔｕｒａｌｕｓｅｓａｔｅｌｅｖａｔｅｄｔｅｍｐｅｒａｔｕｒｅｂｅｃａｕｓｅｏｆｔｈｅｉｒｅｘｃｅｌｌｅｎｔｃｏｒｒｏｓｉｏｎｒｅｓｉｓｔａｎｃｅａｎｄｒｅｌａｔｉｖｅｌｙｌｏｗｍａｔｅｒｉａｌｃｏｓｔ.Ｈｏｗｅｖｅｒ,ｔｈｅｓｅａｌｌｏｙｓｈａｖｅｎｏｔｙｅｔｆｏｕｎｄｗｉｄｅｓｐｒｅａｄｕｓｅｂｅｃａｕｓｅｔｈｅｙｅｘｈｉｂｉｔｐｏｏｒｄｕｃｔｉｌｉｔｙａｎｄｂｒ… 相似文献
8.
用于水基磁流体制备的环境友好分散剂的选择 总被引：1，自引：0，他引：1
用共沉淀法在室温条件下制备纳米Fe3O4磁性粒子,选用聚乙二醇、明胶、琼脂等环境友好分散剂制备水基磁流体。最佳工艺条件为：（1）Fe^3＋／Fe^2＋（物质的量）之比在1．70～1．75;（2）沉淀剂25％NH3·H2O过量（20-30）％,在温度35℃,pH值10-11,搅拌速度3000r／main,反应时间为1h;（3）琼脂、明胶的最佳用量为（0．050～0．060）g／150mL;包覆的最佳温度为（55～60）℃,pH值为9～11;聚乙二醇作为第二次包裹时,最佳温度为55℃,搅拌速度3000r／min,反应时间是1h;并用透射电镜、分光光度计、古埃磁天平等进行了初步表征。在Fe3O4粒子中加入镝（n（Fe）：n（Dy^3＋）=14：1）,明显提高了磁性。 相似文献
9.
The western Iratsu mass, the largest tectonic body in the Sambagawa metamorphic belt, central Shikoku, is mainly composed of epidote amphibolite with minor amounts of eclogite. Systematically, a majority of garnets show bell-shaped chemical zoning of pyrope contents and Mg/(Mg Fe2 ) monotonously increasing outward. The grossular component in zonal garnet increases outwards, maximizes at an intermediate part, and then decreases towards the outermost rim, reflecting a process from increasing to decreasing pressure conditions during the prograde metamorphism. Jadeite contents of omphacite range from 25～20mole% within the cores to 15～10 mole% at the rims, implying a pressure-decreasing process (from 11 × 105 Pa to 8 × 105 Pa). The peak pressure-temperature (P-T) condition of 630～680 ℃ and ca. 15× 105 Pa in the western Iratsu mass is much higher than that of (610±25) ℃ and (10± 1)× 105 Pa of the Sambagawa oligoclase-biotite zone schists. The authors suggest a clockwise P-T-t path for the western Iratsu mass. 相似文献
10.
Zhu ZZ Liu B Wang AZ Jia HR Jin XX He XL Hou LF Zhu GS 《Journal of Zhejiang University. Science. B》2008,9(11):847-852
Objective: To evaluate the association between p53 codon 72 polymorphism (R72P) and the risk of colorectal liver metastases. Methods: The p53 R72P genotype was identified by polymerase chain reaction-restriction fi'agment length poly-morphism (PCR-RFLP) method in 78 consecutive colorectal cancer patients with liver metastases and 214 age- and sex-matched cases with nonmetastatic colorectai cancer. Results: The R allele of the p53 R72P polymorphism was more frequently found in metastatic cases than in nonmetastatic cases (P=0.075). Carriers of the 72R allele had a 2.25-fold (95% CI (confidence inter-val)=1.05～4.83) increased risk of liver metastases. On the stratification analysis, 72R-carrying genotype conferred a 3.46-fold (95% CI=1.02～11.72) and a 1.05-fold (95% CI=0.36～3.08) increased risk of liver metastases for p53 overexpression-positive and negative colorectal cancers, respectively. Conclusion: These results demonstrate for the first time that the 72R allele of the p53 polymorphism has an increased risk for liver metastases in colorectal cancers positive for p53 overexpression. 相似文献
11.
赵升升 《深圳职业技术学院学报》2012,(3):51-54
采用电弧离子镀工艺,调节N2分压制备了系列（Ti,A1）N硬质涂层,研究了不同N2分压对涂层表面形貌、相结构、成分及力争性能的影响．结果表明,当氮气分压较低时,涂层金属相含量较高,涂层硬度和残余应力较低,膜／基结合力较高,涂层耐磨性较差;当氮气分压较高时,涂层氮化物相含量较高,涂层硬度和残余应力较高,膜／基结合力偏低,涂层耐磨性很强． 相似文献
12.
The flame structure of gasoline engine is complicated and has the characteristic of fractal geometry. A fractal combustion model was used to simulate the engine working cycle. Based on this model, the fractal dimension and laminar flame surface area of turbulent premixed flames were studied under different working conditions. The experimental system mainly includes an optical engine and a set of photography equipment used to shoot the images of turbulent flame of spark-ignition engine. The difference box-counting method was used to process 2D combustion images. In contrast to the experimental results, the computational results show that the fractal combustion model is an effective method of simulating the engine combustion process. The study provides a better understanding for flame structure and its propagation. 相似文献
13.
利用公式△H=-0．1196n／A计算了乙醚和丙酮分别在氧气和空气中燃烧反应的温度,并推测了乙醚和丙酮燃烧反应的机理．乙醚在氧气中燃烧反应的火焰温度理论值为3272K,与测定温度3134K接近,误差为4．40％．丙酮在空气中燃烧反应的火焰温度理论值为1292K,与测定温度173K接近,误差为1．49％．根据乙醚和丙酮燃烧反应的火焰温度,推测乙醚和丙酮燃烧反应机理为：（1）O2＋hv→2O·;（2）（C2H5）2O→4C＋4H2＋H2O（乙醚）,CH3COCH3→3C＋2H2＋H2O（丙酮）;（3）H2＋O·→H2O＋hv;（4）C＋O·→CO＋hv;（5）2CO＋O2→2CO2． 相似文献
14.
Fred Punzo 《Learning & behavior》1974,2(1):31-33
Thirty aquatic diving beetles,Rhantus atncolor, of the family Dytiscidae, were subjected to 1-, 5-, 10-, 15-, 20-, and 25-min levels of oxygen deprivation. The level of deprivation was procured by submerging the Ss under water for the allotted period of time. A control group receiving no oxygen deprivation was also tested. The results clearly established oxygen deprivation as a drive state capable of increasing the general level of activity in aquatic Coleoptera as measured by swimming speed in the runway. Significant differences were also found between these deprivation levels. 相似文献
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16.
燃烧热测定过程中氧弹内极限温度和极限压力的预测 总被引：2，自引：0，他引：2
利用平均热容法和理想气体状态方程,预测了苯甲酸燃烧热测定过程中氧弹内的极限温度和极限压力。这些结果对安全地测定燃烧热具有指导意义。 相似文献
17.
张俊斌 《福建工程学院学报》2003,1(3):49-51
通过某小区三幢住宅楼9根小截面静压预制桩静载试验成果分析，表明以侧阻力为主的摩擦型预制桩Q—s曲线呈双曲线的特征。采用斜率-倒数法对该小区静压预制桩单桩极限承载力进行预测，并将预测结果与理论计算结果进行对比，分析结果表明《建筑桩基技术规范》JGJ94—94中有关预制桩承载力指标的取值偏低，其指标不适合小截面静压预制桩。结合桩基施工终压力和每延米压桩耗能的对比分析，表明桩的竖向极限承载力与终压力存在一定的比例关系，但与压桩耗能不存在比例关系。 相似文献
18.
研究了在TritonX 100存在下Hg(SCN)42- 与亮绿的显色反应条件,建立了一种吸光光度法测定微量汞的新方法,汞量在(0 5)μg/25 mL范围内符合比尔定律,方法已用于环境水中微量汞的测定,RSD为0.26%~1.39%,回收率为96.6%~100.2%. 相似文献
19.
McNeil NM Fyfe ER Petersen LA Dunwiddie AE Brletic-Shipley H 《Child development》2011,82(5):1620-1633
This study examined whether practice with arithmetic problems presented in a nontraditional problem format improves understanding of mathematical equivalence. Children (M age = 8;0; N = 90) were randomly assigned to practice addition in one of three conditions: (a) traditional, in which problems were presented in the traditional "operations on left side" format (e.g., 9 + 8 = 17); (b) nontraditional, in which problems were presented in a nontraditional format (e.g., 17 = 9 + 8); or (c) no extra practice. Children developed a better understanding of mathematical equivalence after receiving nontraditional practice than after receiving traditional practice or no extra practice. Results suggest that minor differences in early input can yield substantial differences in children's understanding of fundamental concepts. 相似文献
20.
张瑞 《安阳师范学院学报》2003,(2):84-86
在轧机加热炉上使用纯氧作助燃燃料，比矿物燃料效串高并且减少了氧化氮N0x及二氧化碳CO2的排放量，同时提高了工厂的生产率和灵活性。从Lamines Marchands Europeeens(LME)的短期研究表明了这项技术的实践应用性。 相似文献