EFFECTS OF Pb COMPOUND ADDITIVES ON THE PROPERTIES OF YBa_2Cu_3O_(7-δ)

The melting temperature and critical transition temperature Tc of YBa2Cu3O7-δ with deferent content additives of PbO and BaPbO3 were studied. When PbO was doped in YBa2Cu3O7-δ, the melting temperature of YBa2Cu3O7-δ was reduced, however its superconductivity was weakened. From the XRD pattern of the sintered mixture of YBa2Cu3O7-δ and PbO, it was known that there was a reaction between YBa2Cu3O7-δ and PbO, and the product was BaPbO3. Hence different contents of BaPbO3 (10mass%, 20mass% and 30mass%) were added in YBa2Cu3O7-δ. It was proved that there were no reactions between YBa2Cu3O7-δ and BaPbO3. And the superconductivity of the mixtures was much better than that of the samples with PbO additive.

The Reductive Addition Reaction of Substituted 2-Chloromethyl-1,3,4-oxadiazole to Aldehydes and Ketones Promoted by Samarium Diiodide

1-（β-Hydroxyalkyl）-l,3,4-oxadiazole derivatives were synthesized via reductive addition reactions of 2-chloromethyl-l,3,4-oxadiazole with carbonyl compounds under mild conditions promoted by SmI2.

Grain selection and growth orientation of prior-β phase for Ti-6-4 during additive manufacturing:insights from a modeling perspective

The microstructure of Ti-6-4 components produced by additive manufacturing suffers from the coarse and elongated prior-β grain,which leads to a decrease of the tensile behavior and the occurrence of anisotropy.To understand and control the grain evolution,a multiscale simulation is applied to investigate the relationship between the grain selection,growth orientation,and the molten pool morphology with the different deposition layer numbers and processing parameters.The accuracy of the simulation is validated by experiments in both qualitative and quantitative ways.Results show that when the grain with unfavorable orientation loses the competitive growth with its neighbors,there will be a great chance that the blocked grain is eliminated in the following layer-and-layer deposition,which leads to the increase of the grain width.The size of the molten pool increases remarkably as the layer number increases,which lays a heavy burden on the stability of the molten pool.The analytical relationship between the molten pool morphology and the grain growth orientation is also deduced.The flat molten pool causes the grains with the <001> direction close to the building direction to have greater survival potential.Besides,decreasing the line power energy shows little effect on the stability of the molten pool and the grain growth orientation,especially when the deposited layer number is large.The revealing mechanisms will help in understanding and further controlling the grain evolution.

Effect of Pelletized Graphite Addition on Properties of Al_2O_3-SiC-C Castables

Al2O3 - SiC - C castables with pelletized graphite addition of 0. 2%, 4% or 6% （by mass, the same hereinafter ） were prepared using brown fused corundum （8 - 5, 5 - 3 and 3 - 1 mm ） , dense fused corundum （ ≤1 and 0. 045 mm） and SiC （ ≤1 and ≤0. 064 mm） its main starting materials with mass ratio of aggregate： matrix = 71： 29, 2% silicon powder and 0. 4% B4C as antioxidants, and pelletized graphite as carbon source, Effect of pelletized graphite addition on physical properties, oxidation resistance, slag resistance arid thermal shock resistance of Al2O3 -SiC- C eastables was researched. The results show that： with the in.crease of pelletized graphite addition, the required water amount of castables increases, the bulk density and strength reduce; with 4% pelletized graphite, the eastable performs the best oxidation resistance; the increase of graphite is beneficial to the improvement of slag penetration resistance and corrosion resistance; with 6% pelletized graphite, the thermal shock resistance is the best.

Effect of TiO2 Addition on Slag Resistance of Lightweight Corundum-spinel Castables

Five lightweight castables containing different TiO2 additions were prepared by using porous corundum - spinel （ MgAl2O4 ） ceramics as aggregate. Corrosion of the lightweight cstables by ladle slag was conducted using a static crucible test. The effect of the TiO2 addition on the slag resistances of the lightweight corundum -spinel castables was investigated through SEM, EDS and Fact- Sage@ software, etc. h was found that TiO2 additi,ve t,vmoted the sintering degree of the castables, deereased the average pore .size, the apparent porosity, and the contact area between the casmbles and slag, and then en- hanced the corrosion resistance. However, TiO2 additive decreased the viscosity of the penetrated .slag simultane- ously, and then deteriorated the penetration resistance.

In-situ experiment tests and particulate simulations on powder paving process of additive manufacturing

In this work,in-situ experimental tests are first performed to investigate the powder spreading process of additive manufacturing,where different kinds of scrapers and spreading speeds are employed.Detailed kinetic behaviours of individual powder particles are discussed by discrete element method simulations.It is found that the decrease of inclination angle of the scraper improves the powder pressure and compaction in the spreading process,leading to a denser powder flow and thus a denser powder bed.The increase of spreading speed also improves the powder pressure and compaction in the spreading process.However,the powder flow becomes looser due to the volume dilation,and thus the quality of the paved powder bed decreases.In industrial applications,if the higher powder spreading speed is employed to improve the processing efficiency,the scraper with a smaller inclination angle can be used to ensure the powder bed quality.

Synthesis and characterization ofα-{ 3-[2-hydroxy-3-(N-methyl-N-hydroxy-ethylamino)propoxy]propyl}-ω-butylpolydimethylsiloxanes

α-{ 3-[2-hydroxy-3-（N-methyl-N-hydroxyethylamino）propoxy]propyl }-α-butylpolydimethylsiloxanes III with various molecu- lar weights were prepared by epoxy addition of α-[3-（2,3-epoxy-propoxy）propyl]-α-butylpolydimethylsiloxanes Ⅱ and N- methylmonoethanolamine. At each step, the outcome compounds were characterized through FT-IR and NMR spectra, the results showed that each step was successfully carried out and objective products were achieved.

气象观测场在汽车试验场中的应用研究

汽车试验场作为汽车开展道路测试的重要场所,用于验证汽车产品的品质以及可靠性。除了场地道路外,气象条件作为汽车道路测试的重要一环,在《GB/T12534-1990汽车道路试验方法通则》中也有明确要求,如:试验时应是无雨无雾天气,相对湿度小于95%,气温0-40℃,风速不大于3m/s。同时气象条件也作为试验场道路管控的重要依据,实时风速、雨量、能见度等信息为场地管理者发布限速、限行、封场等通知提供必要参考依据,直接影响道路测试安全管控的及时性。因此,文章从气象观测场的建设、气象服务、异常天气道路管控等方面开展气象观测场在汽车试验场中的应用研究。

Synthesis and Structure of N-(E)-Enoyl(-)-bornane-10,2-sultams

Two potential chiral auxiliaries, N (E ) enoyl(-) bornane 10,2 sultams, were synthesized from (-) bornane 10,2 sultams. The molecular crystal structures of the title compounds were determined by diffraction analysis. The crystal of C 16 O 3SNH 25 belongs to a rhombic system, the space group is P 2 12 12 1 with cell parameters: a =0 734 6(7) nm, b =1 142 7(3) nm, c =2 009 7(3) nm, β =90 00°, V =1 686 9 nm 3, Z=4, D c=1 250 g/cm 3, μ =1 926 cm -1 and F (000)=672. The crystal of C 15 O 3SNH 23 belongs to a rhombic system, the space group is P 2 12 12 1 with cell parameters: a =0 738 2(2) nm, b =0 921 6(1) nm, c =2 280 9(8) nm, β =90 00°, V =1 551 7 nm 3, Z =4, D c=1 273 g/cm 3, μ =2 504 cm -1 and F (000)=640. The structural characteristics with respect to the potential utility for the stereoselective Michael addition reaction of the N enoyl group are discussed.

Formation of Hybrid Ring Structure of Cyanurate/Isocyanurate in the Reaction be-tween 2,4,6-Tris(4-Phenyl-Phenoxy)-1, 3,5-Triazine and Phenyl Glycidyl Ether

Reaction products of 2,4,6-tris(4-phenyl-phenoxy)-1,3,5-triazine derived from 4-phenylphenol cyanate ester and phenyl glycidyl ether were analyzed. In addition to an isocyanurate compound and an oxazolidone compound which were well known as reaction products of cyanate esters and epoxy resins, compounds with hybrid ring structure of cyanurate/isocyanurate were determined. Gibbs free energies of the compound having hybrid ring structure of cyanurate/isocyanurate with two isocyanurate moiety were found to be lower than that of the compound with cyanurate ring structure through calculations. Calculation data supported the existence of hybrid ring structure of cy-anurate/isocyanurate. It was revealed that isomerization from cyanurate to isocyanurate occurs via hybrid ring structure of cyanurate/isocyanurate in the reaction of aryl cyanurate and epoxy.

催化裂化油浆抽提油作橡胶添加剂的研究

对炼油厂催化裂化油浆抽提分离所得抽提油用作橡胶添加剂进行了研究。在抽提油中不加入任何添加剂并保证抽提油全部利用的前提下,通过调整操作条件,将其切割成馏程为80～290℃的轻馏分、291～330℃的中馏分、大于331℃的重馏分。轻馏分与中馏分以1.0:1.0的比例(质量比)混合后得到的混合油的性质符合橡胶填充油质量行业标准KA8012的要求,中馏分质量符合橡胶软化剂质量行业标准芳烃油子午胎专用Ⅱ的要求。重馏分以1.0:5.0的比例(质量比)掺人道路沥青中,提高了道路沥青的耐高温性能。经过核算,催化裂化油浆抽提油利用的经济效益显著。

温拌沥青混合料添加剂Sasobit对道路石油沥青技术指标的影响

通过实验室试验,探讨温拌沥青混合料添加剂Sasobit对道路石油沥青主要技术指标的影响。试验与分析显示,Sasobit可以增加沥青的稠度,当掺量等于大于基质沥青质量的2%时,沥青的标号将从70#降低一个等级成为50#。沥青针入度指数随添加剂掺量的增加先增大到某个最大值然后减小,常用的3%掺量可以显著改善沥青对温度的敏感性。沥青当量软化点随添加剂掺量的增加先增大然后大体维持在常量,常用的3%掺量可以使沥青当量软化点较基质沥青提高约10℃。但是,沥青延度随添加剂掺量的增加持续降低,2%的Sasobit可以使沥青10℃延度从28.5 cm降低到12.0 cm,以致不能满足规范要求。

Honeywell温拌剂在SMA沥青混合料中的添加方法及性能研究

基于SMA-13沥青混合料,对Honeywell温拌剂进行了干法、湿法工艺的路用性能评价,并与SBS改性沥青混合料进行了对比.结果表明,该温拌剂在湿法使用时,可以赋予基质沥青较高的模量和高温粘度,并在30~65℃温度区间保持稳定粘弹性结构,降低沥青的温度敏感性.在干法使用时,该温拌剂可以在玄武岩颗粒表面形成裹附膜,有效提高沥青与玄武岩集料的粘附性等级;在采用基质70号沥青相同的生产温度下,干法添加0.3%的温拌剂生产的SMA混合料较好地满足了改性沥青混合料的相关要求,其路用性能与SBS改性沥青混合料相差不大,实现了一定的温拌效果.

旧水泥混凝土路面沥青罩面层的设计与施工探讨

结合3 1 6国道十堰段旧水泥混凝土路面的改造工程,介绍旧水泥混凝土路面上加铺沥青面层的结构设计和施工方法,以及玻纤格栅和土工布的应用。

劣质稠油制备A级道路沥青的工艺研究

研究了助剂LHA-1在不同添加量下对劣质稠油直馏沥青的储存与使用性能的影响。结果表明,与同标号直馏沥青相比较,LHA-1的加入可有效地改善沥青的高温性能、感温性能及抗老化性能,同时对沥青的延度(尤其是TFOT后的延度)也有一定的改善作用,从而开发确定了利用劣质稠油与LHA-1来制备交通部A辍道路沥青的新工艺。

Synthesis of New Chiral [2-（1-Hydroxyalkyl）pyrrolidino]methylferrocenes and Application to the Catalytic Asymmetric Addition of Diethylzinc to Arylaldehydes

A series of new optically active [2-（1-hydroxyalkyl）pyrrolidino]methylferrocenes were conveniently prepared from commercially available L-proline and ferrocenecarboxylic acid. The crystal structure of key intermediate was obtained. They were then applied to catalyze enantioselective addition of diethylzinc to arylaldehydes with enantioselectivity up to 99%. The effects of the ligand structures on the enantioselectivity were also studied.

浅析旧水泥混凝土路面加铺沥青结构设计方法

本文结合某国道路面改造工程项目案例,综合分析了旧路加铺沥青结构的设计方法,以提高道路的路面使用性能。本方法依据旧水泥混凝土路面使用性能指数(PQI)、病害状况调查、旧路面接缝传荷系数调查和旧混凝土路面结构参数调查结果,先对原路面沥青加铺前进行病害处治设计和沥青结构层设计;其次通过交通量预测分析及设计轴载计算,确定了(4+6)cm沥青上下层厚度和8cm沥青稳定碎石层厚度;最后确定了对于路面损坏状况分级为中级及以上的路段设计采用直接加铺法,对于路面损坏状况分级为次级及以下的路段设计采用发裂稳固后加铺法。

水泥路面碎石化加铺沥青层的弯沉与应力研究

为了提高旧水泥路面改造后的通行能力并延长其使用寿命,对碎石化技术在车辆荷载引起的沥青层表面弯沉和沥青层底最大拉应力方面进行研究。首先介绍了计算路面结构应力应变分量的弹性地基板理论,后应用ABAQUS建立旧水泥路面的复合路面有限元模型,分析了预留裂缝路面结构与碎石化路面结构中表面沥青层弯沉值和沥青层底最大拉应力的变化情况。结果表明在旧水泥路面碎石化后,预留裂缝处沥青层表面弯沉值和沥青层底最大拉应力都减小,碎石层弹性模量增大时,沥青层表面弯沉值和沥青层底最大拉应力逐渐减小,沥青层弹性模量增大时,沥青层表面弯沉值减小,沥青层底最大拉应力增大。

旧沥青路面上直接加铺水泥混凝土面层的应用研究

在对旧沥青路面的病害进行挖补维修处理后,与以往研究采用的加铺超薄层小板块混凝土不同,而是采用直接加铺常用板块尺寸的普通水泥混凝土面层。这一研究经过试验路五年的运营考验,路面使用状况良好,可在不中断交通的道路改扩建工程中推广应用。

Wang Resin-supported Enantioselective Catalysts for the Asymmetric Michael Additions of Acetone to β-Nitroolefins

Two Wang resin-supported （1R,2R）-（＋）-1,2-DPEN（DPEN=diphenylethylenediamine） catalysts were synthesized from cyanuric chloride and trimesoyl chloride, respectively. These two catalysts were characterized by FTIR, TGA and elemental analysis. The results demonstrated that （1R,2R）-（＋）-1,2-DPEN was successfully bonded to the surface of Wang resin through the amido linkage. Subsequently, the asymmetric Michael addition of acetone to β-nitrostyrene was employed to evaluate their catalytic performance. It was found that the catalyst generated from trilnesoyl chloride exhibited much better catalytic behavior than our previously reported catalyst, likely attributed to the multiple hydrogen-bond interaction between β-nitrostyrene and amide group, which made the catalytic transition intermediates more stable. Under the optimal conditions, 76.1% β-nitrostyrene conversion and 93.8% enantioselectivity were obtained. Finally, the generality of this catalyst was examined with Michael additions of acetone to β-nitroolefms and excellent enantioselectivities（91.9% to 99.9%） were achieved.