多产轻烯烃的催化裂化技术

生产轻烯烃是９０年代ＦＣＣ技术发展的趋势。提高反应温度并加入１０％或２０％ＺＳＭ－５，异丁烯产率可分别达到４．５％和５．４％；使用ＲＦＧ催化剂时异丁烯产率可达４．０％，使用ＩｓｏＰｌｕｓ催化剂时异丁烯产率可达４．２％，异戊烯产率可达４．５％。使用ＭＧＧ，ＤＣＣ和ＭＩＩ工艺时，轻烯烃产率高，投资少，见效快，是我国增产轻烯烃的最佳途径。     

ZA—5型氨合成催化剂的研究：基本物化特性与表征

我国Ｆｅ１－ｘＯ基催化剂体系的创立为熔铁催化剂的发展开辟了一条新途径。经多年努力,在Ｆｅ１－ｘＯ催化剂体系和Ａ３０１型催化剂基础上又开发成功低温高活性的ＺＡ－５型催化剂,运用ＸＲＤ、ＸＰＳ、ＳＥＭ、Ｍｏｓｓｂａｕｅｒ、Ｎ２ＴＰＤ、ＴＧ－ＤＴＧ和ＢＥＴ及化学吸附等方法研究了ＺＡ－５型催化剂的化学组成、晶体结构、表面组成和表面结构等基本物化特性。     

导电硅橡胶的研究

研究了导电炭黑的品种、用量、并用和硅烷偶联剂对炭黑表面预处理等因素对硅橡胶硫化胶导电性能、力学性能等方面的影响。研究结果表明,华光特ＨＧ４型导电炭黑的导电性能优于乙炔炭黑,采用华光特ＨＧ４型导电炭黑和乙炔炭黑并用,并对其表面进行预处理,可制得综合性能良好的导电硅橡胶。     

ZBBXE（SG）型固定式包装机自动称量系统改进

ＺＢＢＸＥ（ＳＧ）型固定式包装机自动称量系统改进胡金江，李拓元天津化工厂计控处（３００４８０）裴祥震，李继萱天津化工厂水泥分厂（３００４８０）我厂使用的是ＺＢＢＸＥ（ＳＧ）型机械秤固定式双嘴包装机。使用中的主要问题是包装重量波动较大。通过对该机自动称...     

Z409／Z405G轻油蒸汽转化制氢催化剂首次工业应用

详细介绍了国产Ｚ４０９／Ｚ４０５Ｇ轻油蒸汽转化催化剂在以轻油为原料的３０万吨／年合成氨装置一段转化炉工业应用情况。在同样的工艺条件下。与国外进口的名牌催化剂相比，国产Ｚ４０９／Ｚ４０５Ｇ催化剂表现出良好的应用性能，催化剂在使用过程中活性良好，出口芳烃低于同条件应用的进口催化剂，虽经９次开停车，催化剂经历了多次氧化还原，转化活性一直比较稳定，床层阻力没有增加。卸出催化剂分段取样，进行了分析评价，数据表明，Ｚ４０９／Ｚ４０５Ｇ催化剂表现出良好的抗积炭性、低温还原性、稳定的活性和机械强度。     

用芒硝制取硫酸钾的新工艺研究

根据Ｋ＾＋、Ｎａ＾＋／／Ｃｌ＾－，ＳＯ４＾２－－Ｈ２Ｏ四元水盐体系相图，确定了由芒硝和氯化钾制取硫酸钾的工艺路线。研究了不同加水量对复盐钾芒硝产量、产品硫酸钾产量及质量的影响。制得了符合ＺＢＧ２１００６－８９标准的一等品硫酸钾。研究了不同蒸发水量对副产品氯化钠产量及质量的影响，制得了符合ＧＢ５４６２－８５标准的一级品氯化钠。     

民用型煤复合粘结剂与成型工艺参数的研究

介绍了新研制的ＨＧ１ＨＹ１型复合粘结剂，确定了型煤成型的主要工艺参数。研究结果表明，使用ＨＧ１ＨＹ１型复合粘结剂替代粘土，改革了传统民用型煤粘结剂配方，提高了型煤热值，减少了灰渣量。     

筒体与接管的斜开孔结构设计

从制造工艺和应力集中现象综合分析，讨论了斜开孔接管轴线与容器表面法线的夹角取值范围，并对标准ＨＧＪ１７－８９中这类接头形式作了补充。／     

唐钢FTSC薄板坯连铸中间包包盖用浇注料剥落的原因

薄板坯连铸中间包包盖(以下简称中包盖)在使用中受冷热交替作用和温度波动影响,使用条件苛刻。因此,中包盖用浇注料应具有良好的抗热震性能和较高的高温抗折强度以满足生产需要。但在实际使用中,耐火材料经常会出现分层剥落现象,从而降低了中包盖的使用寿命。浇钢或烘包时,剥落     

φ4.5m×110m窑滚圈开裂分析及焊接工艺

我厂窑轮带ＺＧ３１０－３７０铸钢滚圈在交变应力的作用下发生开裂,通过对１号窑Ⅲ、Ⅳ档滚圈的多次修复,采用手工电弧焊的方法,成功地解决了ＺＧ３１０－３７０铸钢特大厚壁件的焊接工艺,自１９９７年运行至今,使用效果良好。     

Method of determining wear of the working profile of spinning and twisting rings

Conclusions The suggested method for determining wear in spinning or twisting rings makes it possible to establish with adequate accuracy the magnitude of wear in any previously selected point of the ring working surface, and also the change in profile of the frictional surface of the ring in one or several sections, marked off by basis marks.The use of the examined method is advisable in tests of new rings under various conditions, for technological control of the geometric parameters of rings during fabrication, and for determining the profile form of the working surface of rings after operations of repair restoration.Translated from Khimickeskie Volokna, No. 2, pp. 39–40, March–April, 1987.     

Two Distinct Modes of DNA Binding by an MCM Helicase Enable DNA Translocation

A six-subunit ATPase ring forms the central hub of the replication forks in all domains of life. This ring performs a helicase function to separate the two complementary DNA strands to be replicated and drives the replication machinery along the DNA. Disruption of this helicase/ATPase ring is associated with genetic instability and diseases such as cancer. The helicase/ATPase rings of eukaryotes and archaea consist of six minichromosome maintenance (MCM) proteins. Prior structural studies have shown that MCM rings bind one encircled strand of DNA in a spiral staircase, suggesting that the ring pulls this strand of DNA through its central pore in a hand-over-hand mechanism where the subunit at the bottom of the staircase dissociates from DNA and re-binds DNA one step above the staircase. With high-resolution cryo-EM, we show that the MCM ring of the archaeal organism Saccharolobus solfataricus binds an encircled DNA strand in two different modes with different numbers of subunits engaged to DNA, illustrating a plausible mechanism for the alternating steps of DNA dissociation and re-association that occur during DNA translocation.     

纳米SiO2改性PE-Xa记忆环的制备及性能研究

主要针对普通过氧化物交联聚乙烯(PE-Xa)记忆环回缩慢、回缩力小、安全可靠性差等问题,制备出一种新型纳米二氧化硅(SiO₂)改性PE-Xa记忆环。首先研究了交联度对记忆环性能的影响,结果表明,记忆环回缩速度和回缩力均随交联度的提高而提高。其次研究了纳米SiO₂的表面处理及添加量对记忆环性能的影响,结果表明,采用硅烷偶联剂KH-570对纳米SiO₂进行表面处理,并且在线速度1 km/min以上的超高速搅拌下混合,纳米SiO₂的分散性较好。添加1.5%表面处理的纳米SiO₂能大幅提高记忆环回缩速度、回缩力和抗蠕变性能。对制备的记忆环进行性能测试,其回缩速度,回缩力均优于市售记忆环,且通过了交联聚乙烯(PE-X)管标准中规定的静液压状态下的热稳定性试验和系统适用性中规定的静液压试验。     

Computational Fluid Dynamics Study of Flow Induced by a Grooved High‐Shear Impeller in an Unbaffled Tank

A detailed hydrodynamic characterization in the transitional flow regime of two variants of the Norstone Polyblade® high‐shear impeller (HSI), of industrial relevance, is presented. The study was carried out on a simulated Newtonian fluid using computational fluid dynamics (CFD). Measurements of power number were carried out to validate the simulation results. Hydrodynamic parameters considered of key importance in powder dispersion processes (i.e., viscous dissipation and effective circulation) were used to assess the impellers' performance. Furthermore, their performances were compared with reported data for two ring‐style HSIs of two and four rings, and power number measurements of a sawtooth (Cowles‐type) impeller.     

大菱形孔端面密封力变形及密封性能分析

针对等深大菱形孔端面液体润滑机械密封,采用有限差分法求解等温及层流不可压缩二维Reynolds方程,获得液膜压力场。利用商用有限元软件计算密封环三维固体变形,对不同操作工况条件下和不同结构的密封环的力变形、摩擦扭矩、液膜刚度及泄漏率等性能参数进行了计算。结果表明：大菱形孔流体动压型机械密封端面产生周向波度和径向锥度变形;改变工况条件可使密封面形成收敛和发散两种不同的变形,密封性能参数因此产生显著变化;当面积比B=0.65～0.75时,大菱形孔端面密封可获得较好的密封性能;辅助密封圈O形圈位置l对径向锥度变形具有很大影响,l优选值范围为2.4～4.0 mm。     

新型均流填料塔的传质性能研究

提出了一种新型均流填料塔设备,在Φ600 mm的圆形冷模实验塔中,以空气-水-CO2为工质进行了CO2解吸试验,利用滴定法测定了多种气液负荷下新型均流填料塔的传质性能,并在相同工况下与鲍尔环填料塔进行了对比研究。试验结果表明:在试验喷淋密度下,新型均流填料塔与鲍尔环填料塔相比,液相传质单元高度降低了19%以上;随着喷淋密度的降低,液相传质单元高度降低更加显著。在正常操作范围内,新型均流填料塔的传质效率远高于鲍尔环填料塔,是一种传质性能优良的新型填料塔设备。     

铸型尼龙活塞环的研制

采用铸型(MC)尼龙活塞环代替玻纤增强聚四氟乙烯(PTFE/GF)活塞环用于空气分离器,活塞环的使用寿命为PTFE/GF活塞环的1.5倍。分析了MC尼龙活塞环优于PTFE/GF活塞环的原因。     

Structural Fluctuations of the Human Proteasome α7 Homo-Tetradecamer Double Ring Imply the Proteasomal α-Ring Assembly Mechanism

The 20S proteasome, which is composed of layered α and β heptameric rings, is the core complex of the eukaryotic proteasome involved in proteolysis. The α7 subunit is a component of the α ring, and it self-assembles into a homo-tetradecamer consisting of two layers of α7 heptameric rings. However, the structure of the α7 double ring in solution has not been fully elucidated. We applied cryo-electron microscopy to delineate the structure of the α7 double ring in solution, revealing a structure different from the previously reported crystallographic model. The D7-symmetrical double ring was stacked with a 15° clockwise twist and a separation of 3 Å between the two rings. Two more conformations, dislocated and fully open, were also identified. Our observations suggest that the α7 double-ring structure fluctuates considerably in solution, allowing for the insertion of homologous α subunits, finally converting to the hetero-heptameric α rings in the 20S proteasome.     

环路热管中Ti64ELI毛细芯传热能力的实验研究

在环路热管（LHP）中,蒸发段的结构最为复杂,而其中的毛细芯是直接影响热管工作性能的部分,因此有很大的研究价值。为模拟LHP中毛细芯的真实运行情况,设计了一台在常温下测定毛细芯工作时表面温度的实验装置,对环路热管蒸发段毛细芯的传热能力进行独立的实验研究,分别采用乙醇和水为工质,在不同的加热功率下,计算毛细芯的有效热导率。研究发现,在低加热功率下,含乙醇的毛细芯的有效热导率要高于含水的毛细芯的有效热导率;而在高加热功率下,实验结果正好相反。本次实验的结论对于毛细芯传热性能的评估具有一定参考价值,也可以为LHP蒸发器的模拟仿真提供一定的实验数据。     

叶轮前后口环直径对轴向力的影响

通过对端吸单级、节段式多级泵的轴向力平衡结构产生轴向力的计算,对不同结构的计算比较,表明前后密封环加平衡孔结构,并非前后密封环直径相等是最合理的平衡轴向力结构,而是后密封环比前密封环直径小,更有利于轴向力的平衡.