一种新型增力式同步器设计

为减小换挡同步阶段需要换挡机构提供的换挡力,提出一种新型同步器结构,利用换挡同步阶段同步环受到的切向力差值,放大换挡机构输出的换挡力。建立了增力式同步器工作过程力学模型,在此基础上分析了影响增力式同步器性能的主要设计参数。仿真研究结果表明,某型号5挡变速器采用增力式同步器后,在常用换挡参数下换挡时,同步阶段需要换挡机构输出的换挡力减小近40%,能量损耗约降低66%。     

液态发酵生产水溶性红曲黄色素的条件优化

以红色红曲菌（Monascus ruber）M-7为实验菌株,以色价和色调为评价指标,对液态发酵生产水溶性红色红曲黄色素的条件进行了研究。结果表明,培养基pH值为3～4时,红色红曲菌M-7能合成大量的水溶性红曲黄色素,发酵液呈鲜艳的黄色色调;培养基最优碳源为2%蔗糖,最优氮源为0.2%硫酸铵;水溶性红色红曲黄色素的色价和色调值随着培养时间的延长先升后降,在第8天时达到最高,色价为5.56 U/mL,OD400 nm/OD510 nm为10.29,OD400 nm/OD470 nm为3.93。     

Biodiesel production from mixtures of canola oil and used cooking oil

Used cooking oil (UCO) was mixed with canola oil at various ratios in order to make use of used cooking oil for production of biodiesel and also lower the cost of biodiesel production. Methyl and ethyl esters were prepared by means of KOH-catalyzed transesterification from the mixtures of both the oils. Water content, acid value and viscosity of most esters met ASTM standard except for ethyl esters prepared from used cooking oil. Canola oil content of at least 60% in the used cooking oil/canola oil feedstock is required in order to produce ethyl ester satisfying ASTM specifications. Although ethanolysis was proved to be more challenging, ethyl esters showed reduced crystallization temperature (−45.0 to −54.4 °C) as compared to methyl esters (−35.3 to −43.0 °C). A somewhat better low-temperature property of ester was observed at higher used cooking oil to canola oil ratio in spite of similar fatty acid compositions of both oils.     

Steam and KOH activation of biochar: Experimental and modeling studies

Biochar was used as a precursor of activated carbon using physical (steam) and chemical (potassium hydroxide) activation processes. The effects of operating conditions for each activation method on the BET surface area of the product and reaction yield were investigated using central composite design (CCD). For both activation processes, quadratic models were developed, by Design-Expert software, for BET surface area and reaction yield. The optimum operating conditions were calculated by the models to produce physically and chemically activated carbons with large surface area and product yield. The optimum BET surface area and product yield of physical activation are, respectively, 643 m²/g and 56.9 wt%, and of chemically activated carbon are, respectively, 783 m²/g and 75.3 wt%, which showed good agreement with the experimental values. Average pore diameters of physically and chemically activated carbons were in the ranges of 13–26 Å and 13–15 Å, respectively.     

Hydrotreating of gas oil on SBA-15 supported NiMo catalysts

The siliceous and the metal substituted (B or Al)-SBA-15 molecular sieves were used as a support for NiMo hydrotreating catalysts (12 wt.% Mo and 2.4 wt.% Ni). The supports were characterized by X-ray diffraction (XRD), scanning electron microscopy and N₂ adsorption–desorption isotherms. The SBA-15 supported NiMo catalysts in oxide state were characterized by BET surface area analysis and XRD. The sulfided NiMo/SBA-15 catalysts were examined by DRIFT of CO adsorption and TPD of NH₃. The HDN and HDS activities with bitumen derived light gas oil at industrial conditions showed that Al substituted SBA-15 (Al-SBA-15) is the best among the supports studied for NiMo catalyst. A series of NiMo catalysts containing 7–22 wt.% Mo with Ni/Mo weight ratio of 0.2 was prepared using Al-SBA-15 support and characterized by BET surface area analysis, XRD and temperature programmed reduction and DRIFT spectroscopy of adsorbed CO. The DRIFT spectra of adsorbed CO showed the presence of both unpromoted and Ni promoted MoS₂ sites in all the catalysts, and maximum “NiMoS” sites concentration with 17 wt.% of Mo loading. The HDN and HDS activities of NiMo/Al-SBA-15 catalysts were studied using light gas oil at temperature, pressure and WHSV of 370 °C, 1300 psig and 4.5 h⁻¹, respectively. The NiMo/Al-SBA-15 catalyst with 17 wt.% Mo and 3.4 wt.% of Ni is found to be the best catalyst. The HDN and HDS activities of this catalyst are comparable with the conventional Al₂O₃ supported NiMo catalyst in real feed at industrial conditions.     

一种新型并联机器人的奇异性与工作空间研究

针对一种六棱锥式新型并联机器人的轨迹规划问题,基于具有反解选取准则的机构逆运动学方程,对奇异性和工作空间进行深入研究。由雅可比矩阵提出机构奇异判别方程,并引入可操作度性能指标进行奇异性分析。考虑运动副范围以及连杆干涉等约束条件,采用三维边界搜索法,给出机构在定姿态下工作空间的三维可视化描述。进行边界采样实验,实验结果表明了仿真的正确性。研究结果可为无奇异轨迹规划提供理论依据。     

3D Coordination Network of Ag(I) Ions with μ 3 -Bridging Melamine Ligands

Abstract  

A new 3D silver complex [Ag(mela)(H₂O)(NO₃)]_n (1) (mela = melamine or 2,4,6-triaminotriazine) is synthesized and characterized by single crystal X-ray diffraction, IR, and elemental analysis. The structural characterization shows that the compound crystallizes in space group C c, a = 8.181(2), b = 10.269(3) c = 11.347(3) ?, β = 105.88(2)°, Z = 4. Out of several structurally characterized transition metal compounds comprising melamine, the titled complex represents a rare example of μ ₃ -melamine coordination mode realized through the heterocycle nitrogen donors. The fluorescent property of complex 1 was investigated and the mechanism was validated by means of a density functional theory (DFT) calculation.     

当代微建筑设计倾向的实验性探索

该文通过探讨当代微建筑的设计倾向,深入研究其历史发展的脉络以及目前存在的问题,对微建筑这一设计倾向的定义、实验性的本质特征进行初步的探究,从而进一步剖析微建筑的实验性技术本质,探寻其背后隐藏的建造理念、技术、材料的创新应用。该文选择相关的微建筑案例进行分析,希望通过发掘这些微建筑案例中体现的“以少见大”的设计本质,以及这种本质所体现的实验性的设计特征,进而启迪和激发当代中国城市建筑、景观设计中的创新精神和思路。     

鸡西盆地致密砂岩气存在的可能性

鸡西盆地的油气勘探程度较低,尤其是对致密砂岩气的研究尚处于起步阶段。在总结国内外成功地区致密砂岩气成藏条件的基础上,从构造、烃源岩以及储层条件等方面探讨了鸡西盆地致密砂岩气的成藏条件。依据鸡D8井暗色泥岩样品的地球化学资料,使用化学动力学法计算了研究区致密砂岩气的资源量。研究表明,鸡西盆地属于小型断陷盆地,多期构造演化与储层快速沉积等特点,决定了研究区不具备类似北美阿尔伯达等成功地区的大型致密砂岩气成藏的地质条件。但鸡西盆地城子河组大规模发育的煤系地层长期生气,为致密砂岩气藏的形成提供了充足的气源,烃源岩与储集层紧密叠置接触也有利于致密气的运移和保存。在鸡西盆地的中央凹陷构造稳定区域,寻找致密储层的甜点区,将有机会获得致密砂岩气藏的勘探突破。     

酸性电解水对苹果表面毒死蜱降解效果及降解途径分析

目的:通过研究不同条件下的酸性电解水对苹果表面毒死蜱的降解效果以及分析毒死蜱的降解途径,为苹果生产加工行业提供理论支持。方法:使用毒死蜱模拟污染苹果表面,在不同有效氯浓度（10、50、100 mg/L）和pH（pH为2.80和5.80）的酸性电解水条件下,采取浸泡处理或振荡清洗苹果的清洗方法,用气相色谱和气质联用方法测定毒死蜱残留和降解产物。结果:通过强酸性电解水降解苹果表面的毒死蜱实验,发现其降解效率与反应时间、有效氯浓度有直接关系,随着反应时间的延长或有效氯浓度的增加,降解效率也增加。当有效氯浓度达到50 mg/L时,浸泡15 min会降解55%以上的毒死蜱残留,并且与对照组自来水浸泡有极显著差异（P<0.01）。当有效氯浓度为100 mg/L时对毒死蜱的降解率超过了70%。在相同条件下强酸性电解水与微酸性电解水在降解毒死蜱的效果上无显著差异（P>0.05）,并且浸泡处理和振荡处理对实验结果没有显著影响（P>0.05）。酸性电解水处理对苹果主要品质指标没有显著影响（P>0.05）。经GC-MS分析,毒死蜱被强酸性电解水降解后,在降解产物中发现毒死蜱氧化物（CPO）和3, 5, 6-三氯吡啶-2-醇（TCP）。其可能的降解途径为毒死蜱→CPO→TCP→小分子有机物→无机物。结论:该研究结果对苹果加工产业在消除农药残留方面提供一种新方法。