Investigation of lanthanum and Si/Al ratio effect on the HZSM-5 catalyst efficiency for production of Olefin from Methanol

The effect of lanthanum and Si/Al ratio on catalytic performance of HZSM-5 in methanol to olefin process is investigated in this paper. The catalyst with bases of HZSM-5 is modified using the lanthanum by a wet impregnation producer. The Box-Behnken method, experimental design is used to evaluate effects of lanthanum parameters, Si/Al ratio, temperature and the effect of the interaction between them in methanol to olefin process for production of ethylene and propylene. Finally, the obtained results show the highest yield of ethylene is achieved for high load lanthanum catalyst, low Si/Al ratio and high temperature.     

数据与模型协同驱动的智能光网络架构与关键技术

网络的规模升级和超大连接、超高带宽、超低时延应用的不断深化，对光传输网络资源利用和网络差异化服务提出了更高要求，使得传统模型驱动下的网络形态和配置方式面临挑战。基于数据与模型协同驱动思想，提出“3层3循环”架构及其“3可功能”特征的智能光网络技术方案，并对智能化实现技术展开研究，通过开发设计的智能传输网络平台对所提算法的性能进行测试，经验证，数据与模型协同驱动的智能光网络传输性能得到有效提升，为实现网络智能化提供了理论技术支撑。     

Isovalent Substitution and Heat Treatments Control of T c, Chain Oxygen Disorder and Structural Phase Transition in High T c Superconductors (Y1−x Nd x )SrBaCu3O6+z

We report here on the preparation, X-ray diffraction with Rietveld refinement, AC magnetic susceptibility measurements and effect of heat treatments in (Y_1?x Nd _x )SrBaCu₃O_6+z . Each sample was subject to two types of heat treatment: oxygen annealing [O] and argon annealing followed by oxygen annealing [AO]. For each x, the [AO] heat treatment increases the orthorhombicity ε=(b?a)/(b+a) (for 0≤x<1), T _c (for x>0.2) and the distance d[Cu(1)–(Sr/Ba)] (decrease T _c) for x<0.25 and decrease it (increase T _c) for x>0.25. When x increase from 0 to 1, ε decreases to 0 with transition from orthorhombic to tetragonal structure. ε[O] decreases with T _c[O]. However, T _c[AO] decreases with ε[AO] until x=0.2, increases for x=0.4 and after it decreases by 9.8 K to 77.2 K for x=1 [AO]. Remarkable correlations were observed between T _c(x) and the volume of the unit cell V(x); and between δT _c(x)=T _c[AO]?T _c[O] and δε(x). A combination of several factors such as decrease in d[Cu(1)–(Sr/Ba)]; increase in cationic and chain oxygen ordering; the number p _sh(x) of holes by Cu(2)–O₂ superconducting plans and in-phase purity for the [AO] samples may account for the observed data.     

Computational fluid dynamic simulation of MVG tray hydraulics

The flow pattern and hydraulics of a Mini V-Grid valve (MVG) tray is predicted by using computational fluid dynamics simulation. A 3-D CFD model in the Eulerian framework was used. The simulation results for MVG tray are compared with that of sieve tray. The sieve tray geometry and operating conditions are based on the Solari and Bell’s sieve tray [1]. The MVG tray differs from that of Solari and Bell’s sieve tray solely by the difference in design of available openings for the flow of gas. The simulation results show that the clear liquid height and the pressure drop of MVG tray are lower than that of sieve tray whereas the liquid velocity is higher and contacts of phases are good. The simulation results of sieve tray are in agreement with the experimental data of Solari and Bell [1].     

G.719: The First ITU-T Standard for High-Quality Conversational Fullband Audio Coding

This article presents an overview of the recently standardized ITU-T G.719 codec, its key technologies, and their impact on audio quality. These technologies, while leading to exceptionally low complexity and small memory footprint, result in high fullband audio quality, making the codec a great choice for any kind of communication devices, from large telepresence systems to small low-power devices for mobile communication.     

Protocols for reliable data transport in space internet

A variety of protocols have been proposed for reliable data transport in space Internet and similar network environments. It is necessary to conduct a survey on these protocols to investigate and compare among them. In this article, we present a survey on the protocols proposed for reliable data transport in space Internet, with a focus on the latest developments. The survey includes the following contents: (1) Classification of these protocols into different approaches; (2) Discussions and comments on the design and operation methods of the protocols; and (3) Comparisons and comments on the main techniques and performance of the protocols.     

Strategies to improve the geometric accuracy in asymmetric single point incremental forming

Asymmetric incremental sheet forming (AISF) is a manufacturing process for the small batch production of sheet metal parts. In AISF, a sheet metal part is formed by a forming tool that moves under CNC control. AISF currently has two dominant process limits: sheet thinning and a limited geometric accuracy. This paper focuses on the latter limit. It is shown with a pyramidal part that multi-stage forming can yield an increased accuracy compared to single-stage forming. However, due to residual stresses induced during forming, the accuracy of the as-formed part can be lost if the part is trimmed after forming. A case study with a car fender section shows that the geometric accuracy of the final part can be improved compared to single-stage forming by a combination of multi-stage forming and stress-relief annealing before trimming.     

Primary vaginal cancer in adults. Apropos of 72 cases treated at the Fondation Curie from 1956 to 1968

Primary vaginal cancer are infrequent and amount to 2 or 3 per cent of the gynecological cancers. Their diagnosis is difficult, because many other cancers metastasize in the vagina. The primary vaginal cancer arise mostly after climateric. Adjuvant causes would be a total hysterectomy in the past, prolapsus, prolonged use a pessary or a previous irradiation. The squamous-cell carcinomas, by far the most frequent (91%), are mostly situated in the upper third of the vagina on the anterior and posterior walls. Surgery, being difficult and mutilating is rarely indicated. So the treatment is mainly radiotherapic: external irradiation and intracavitary curietherapy. The radiation techniques are a little different according to the site of the lesion in the lower third or not. The upper lesion can be treated like a cervix cancer. The lower ones are more difficult to handle; for curietherapy, one must use molded apparatus, loaded with Iridium wire, adapted to each special case. The therapeutic results are rather poor:43 per cent for the 5-year cure rate and 36 per cent for the 10-year cure rate: less than for the cervix uteri. The upper lesions have a better prognosis than the lower ones. Results should be improved with an earlier diagnosis, a more accurate radiotherapy and a more precise dosimetry. The non-squamous-cell cancers (adenocarcinomas, sarcomas, mallignant melanomas) are generally rather radio-resistant. They are rare and their prognosis is very poor.