A graph-based QoS prediction approach for web service recommendation

Applied Intelligence - With the development of the Internet, the recommendation based on Quality of Service(QoS) is proven to be an efficient way to deal with the ever-increasing web services in...     

负氢离子释放剂对2-甲基-2-丁烯氢转移反应的影响

负氢离子转移反应是氢转移反应的基元反应,促进负氢离子转移反应可以强化选择性氢转移反应。在反应温度510 ℃、剂/油质量比5、质量空速12 h^-1、N₂气氛条件下,分别考察了四氢萘和十氢萘作为负氢离子释放剂对2-甲基-2-丁烯氢转移反应的影响。结果表明：四氢萘和十氢萘均能有效地促进2-甲基-2-丁烯发生选择性氢转移反应,产物中C₅烯烃产率由52.95%最低分别降至37.83%和17.03%,异戊烷产率由17.80%最高分别增加至42.98%和54.58%,焦炭产率由5.28%最低分别降至3.11%和2.85%;且十氢萘比四氢萘具有更好的供氢能力,相同含量的十氢萘对于产物中烯烃产率的降低幅度、异构烷烃产率和选择性的增加幅度的影响均比四氢萘更大,对焦炭产率的抑制作用更强。在含烯烃汽油中分别加入质量分数10%四氢萘和十氢萘后,烯烃产率由11.20%分别降低至5.48%和4.01%;同时能够很好地抑制焦炭的生成,尤其加入十氢萘后焦炭产率由5.30%降到2.82%。     

Adaptive full order sliding mode control for electronic throttle valve system with fixed time convergence using extreme learning machine

Neural Computing and Applications - This paper proposes a novel extreme learning machine (ELM)-based fixed time adaptive trajectory control for electronic throttle valve system with uncertain...     

CRP－1裂解催化剂工业应用及15万t／a催化裂解装置开工运转

ＣＲＰ－１裂解催化剂首次工业应用和１５万ｔ／ａ催化裂解工业生产装置开工运转结果表明，新研制的ＣＲＰ－１裂解催化剂具有平衡活性高、机械强度好、轻烯烃选择性好、重油转化能力强的特点，是用于Ⅰ型催化裂解的新一代较理想的裂解催化剂。在５４６℃反应温度下，液化气产率可达４２．００ｗ％，丙烯产率可达１８．３２ｗ％；裂解汽油ＭＯＮ８２．３，ＲＯＮ７．６，装置运转正常，虽然反应强度较高及原料较重，但催化裂解装置设备结焦程度与蜡油催化裂化相当，装置能耗７．０６８９ＧＪ／ｔ原料。工业运转取得了较好的生产数据，为今后大型催化裂解装置的建设和生产提供了宝贵的经验。     

庚烯与H2S在酸性催化剂上反应机理研究I-硫醇等生成机理

 为了研究催化裂化汽油中硫化物的生成机理,在小型固定流化床(FFB)装置中考察了不同质量分数的庚烯与H₂S在固体酸催化剂上的反应.结果表明, 庚烯与H₂S的反应主要生成噻吩类硫化物、部分硫醇、少量硫醚和痕量四氢噻吩等硫化物；庚烯质量分数越高,生成硫化物的量越多; 噻吩类硫化物中生成量最大的甲基苯并噻吩的生成量也随着庚烯质量分数增加而线性增长.烯烃在催化剂B酸活性中心上吸附形成正碳离子, 正碳离子与H₂S结合生成硫醇,硫醇的生成遵循正碳离子机理.硫醇与烯烃反应生成硫醚.当反应温度为400～500℃,庚烯与H₂S反应中,生成硫醇、硫醚的反应均为放热反应,硫醇的平衡收率较低,硫醚的平衡收率更低一些.     

异丙苯裂化反应路径及苯生成影响因素分析

在催化裂化反应条件下，研究了异丙苯主要裂化反应路径以及反应过程中反应温度和分子筛类型对苯产率和选择性的影响规律。结果表明，异丙苯裂化中的主要反应为脱烷基反应和侧链质子化裂化反应，苯主要来自异丙苯的脱烷基反应；高温和择形分子筛有助于提高异丙苯裂化生成苯的产率和选择性；在反应温度为550℃、质量空速为8h-1、剂油质量比为6的条件下，异丙苯在择形分子筛催化剂上裂化生成苯的产率和选择性分别可达40%和55%以上。     

MIP Technology for Pruduction of Euro IV Clean Gasoline II. Correlation Model of Sulfur Content of MIP Naphtha and Its Application

On the basis of the reaction rules and its influencing factors of sulfur compounds in MIP naphtha, a correlation model for describing the correlation between mass fraction of sulfur in MIP naphtha, mass fraction of sulfur in feedstock and volume fraction of olefin in naphtha was developed and the model's parameters were estimated. The residual error distribution and statistical study showed that the developed model was reasonable and reliable and able to predict the mass fraction of sulfur compounds in naphtha. The correlation model can provide theoretical guidance and operation base for adjusting process parameters to produce EURO IV gasoline by the MIP units. The model was validated by its application on the MIP unit of Qingdao Refining & Chemical Company. On this unit, the tail oil with low sulfur content obtained via hydrotreating gas oil was used as the feedstock and the olefin content of naphtha was reduced by promoting hydrogen transfer reaction through adjustment of process parameters. Thus, EURO IV clean gasoline was manufactured by this MIP unit.     

Analysis and design considerations of a load and line independent zero voltage switching full bridge DC/DC converter topology

The analysis and design of a zero voltage switching (ZVS) full bridge DC/DC power converter topology is presented in this paper. The converter topology presented here employs an asymmetrical auxiliary circuit consisting of a few passive components. With this auxiliary circuit, the full bridge converter can achieve ZVS independent of line and load conditions. The operating principle of the circuit is demonstrated, and the steady state analysis is performed. Based on the analysis, a criterion for optimal design is given. Experiment and simulation on a 350-400 V to 55 V, 500 W prototype converter operated at 100 kHz verify the design and show an overall efficiency of greater than 97% at full load.     

单缸柴油机进气系统对充量系数的影响

充量系数直接影响发动机的动力性及经济性,作者试验研究了进气系统各参数对充量系数的影响,并把在静态下得到的结论推广应用到动态状况。并编制了带空滤器边界模型的电算程序,用这个为试验所证实了的方法对充量系数进行了预测,有效地代替了常规试验。     

ZSM-5分子筛上正碳离子发生D、F和G型β键断裂反应的探索研究

在C—C键断裂反应中,普遍认为：由于不同结构的正碳离子存在稳定性差异,导致A、B、C型β键断裂反应较容易发生,而D、E型β键断裂反应在常规条件下几乎不可能发生。针对正碳离子裂化反应机理中乙烯选择性差的问题,深入分析现有实验设计方法的局限性,重新设计实验方法并反复进行了实验研究。结果表明：在特定的催化条件下,能量上非常不利的D型和笔者自定义的F、G型正碳离子β键断裂反应可以在C—C键断裂反应中被有效促进并有助于提高乙烯选择性。这一发现,不仅丰富了正碳离子有机化学反应的内涵,也为乙烯高效生产提供崭新的开发思路。