基于QCS014A实验台的液压马达选型设计

根据QCS014A液压教学实验台已有的条件进行的液压马达选型设计,不同于通常的从负载分析入手的选型设计。已知动力元件和控制元件,该方法通过确定液压系统原理图、计算所需液压马达的主要设计参数、分析液压马达的类型等步骤反推确定液压马达的型号。该方法既简便易行,又能满足设计要求。     

Regional input-output analysis,data and uncertainty

This paper addresses two major issues. The first is the introduction of uncertainty into the framework of classical deterministic regional input-output (I-O) analysis. Secondly, the role of the use of measurable flow data on the fundamental structure of the models is explored. The opening section uncovers an anomaly in the classical approach when flows between regions of final demand products, external exports and imports are neglected in comparison to the flows of internal intermediate inputs. Next, we introduce uncertainty into the analysis by extending an entropy formulation developed by Wilson, which itself evolved from the formalism established by Leontief-Strout (L-S). The main enhancements include (i) the introduction of regional output capacities to capture spillovers from regions operating close to capacity, (ii) the inclusion of flows of external imports and exports and (iii) the use of total measurable flows as input which are readily available from surveys, yielding as output not only the total flows of each sector between each pair of regions, but (optionally) the further disaggregation of these flows to include their final destination sector or their use as final demand. In fact, a key objective is to structurally account for the joint influence of technology, output capacities and transportation costs on the pattern of intermediate and final demand flows between regions. Further extensions of the approach lead to the generation of probabilistic supply functions as tools within a potential CGE analysis. This option requires the introduction of prices, permitting a profit constraint to replace the simple transport cost constraint of the earlier models.Received: August 2000 / Accepted: April 2003     

乙醇催化脱水制乙烯催化剂的制备与性能评价

采用混捏法制备乙醇脱水制乙烯EDE-104催化剂,并引入活性金属氧化物E对催化剂进行改性,通过正交实验得到较优的工艺条件:反应温度360℃,液体空速0.5 h-1,原料乙醇质量分数60%,并在此条件下进行了1 000 h的寿命实验。结果表明,乙醇催化脱水制乙烯催化剂中引入活性金属氧化物E,提高了乙烯选择性,增强了催化剂的稳定性,乙烯选择性97.5%,乙醇单程转化率97.5%,乙烯收率96%。     

The creep behaviour of the ILZRO14 zinc alloy

Microstructural characterization of the ILZR014 alloy shows that it is made up of η phase dendrites, containing ε precipitates, bordered by a multiphased interdendritic zone, consisting of the η/TiZn₁₅ lamellae eutectic and the B phase. The microstructure of this alloy was correlated with the (Zn—Cu—Ti) phase diagram. The TiZn₁₅ lamellae eutectic and the fine semi-coherent ε precipitates play a major role on creep behaviour. It is found that the modification of this alloy by the suppression of the ε phase or by the spheroidisation of the TiZn₁₅ lamellae leads to a deterioration of the creep behaviour. The creep behaviour of the ILZR014 alloy was compared with that of another zinc alloy, ZAMAK5, in which the destabilisation of the interdendritic zone occurs during creep testing.     

Cloning and identification of HEM14, the yeast gene for mitochondrial protoporphyrinogen oxidase

A respiratory-defective mutant (C54) of Saccharomyces cerevisiae was found to have a phenotype consistent with a mutation in either mitochondrial protoporphyrinogen oxidase or ferrochelatase. The mutant is grossly deficient in hemes, accumulates protoporphyrin and is rescued by exogenous heme. The increased levels of protoporphyrin at the expense of heme is indicative of a block in one of the two last steps of the heme biosynthetic pathway. Complementation of C54 by a known ferrochelatase mutant suggested that the defect was most likely in HEM14 encoding protoporphyrinogen oxidase. A plasmid capable of complementing C54 was obtained by transformation with a yeast genomic plasmid library. A partial sequence of the insert identified the gene as reading frame YER014 of yeast chromosome V (GenBank Accession Number U18778). This reading frame codes for a protein homologous to human protoporphyrinogen oxidase. Disruption of this gene elicits a respiratory defect and accumulation of protoporphyrin. The phenotype of the null mutant together with the homology of YER014p to human protoporphyrinogen oxidase provide compelling evidence that YER014 is HEM14.     

Antimetastatic and Antitumor Activities of Orally Administered NAX014 Compound in a Murine Model of HER2-Positive Breast Cancer

The natural isoquinoline alkaloid Berberine (BBR) has been shown to possess several therapeutic effects, including anticancer activity. Different BBR derivatives have been designed and synthesized in order to obtain new compounds with enhanced anticancer efficacy. We previously showed that intraperitoneal (IP) administration of the BBR-derived NAX014 compound was able to counteract HER-2 overexpressing mammary tumors onset and progression in transgenic mice. However, the IP administration was found to induce organ toxicity at doses higher than 2.5 mg/Kg. In this study, we evaluated the effect of intragastric (IG) administration of 20 mg/kg of NAX014 on both safety and anticancer efficacy in HER-2/neu transgenic mice. Furthermore, cancer cell dissemination and migration, tumor cell senescence and immunological changes were examined. Our results demonstrated that IG NAX014 administration delayed the onset of mammary tumors with no negative effects on health and survival. NAX014 reduced HER-2 overexpressing BC cells migration in vitro and the frequency of lung metastasis in HER-2/neu transgenic mice. A statistically significant increase of senescence-associated p16 expression was observed in tumors from NAX014-treated mice, and the induction of cell senescence was observed in HER-2 overexpressing BC cells after in vitro treatment with NAX014. Although NAX014 did not modulate the presence of tumor-infiltrating lymphocytes, the level of circulating TNF-α and VEGF was found to be reduced in NAX014-treated mice. The overall results address the NAX014 compound as potential tool for therapeutic strategies against HER-2 overexpressing breast cancer.