Initial value problem for a class of semi-linear fractional iterative differential equations

An initial value problem of a class of semi-linear fractional order iterative differential equations is studied in this paper. The existence of solution for fractional order iterative differential equations is obtained in Banach space $C(J,J)$ and $C_{K,\alpha}(J,J)$ respectively. However, uniqueness results can not be acquired since the operator only is H\"{o}lder continuous but not Lipschitz continuous. Furthermore, a small perturbation of the initial value will cause a change in the solution on $[k,b]$ for the $k\in J$. Our analysis is based on Schauder"s fixed point theorem and the properties of Mittag-Leffler function. Finally, an example is given to illustrate our results.     

生物浸出回收废弃镍-镉电池研究

在中国,只有不到1%的废弃干电池被回收,因此有必要寻找一种既经济、快速,又利于环保的处理废弃干电池方法.生物浸出是回收废弃干电池有毒金属效果最好的方法之一.本研究应用本地下水道废水经驯化培养后产生的酸性废水作浸出菌种,考察pH值、生化反应器污水停留时间(RTB)、浸取时间、生化反应液是否添加Fe粉等实验条件对废弃镍-镉电池镍、镉浸出率的影响.结果表明,在pH值1.8~2.1、RTB 5 d、浸取时间50 d、生化反应液添加Fe粉条件下,可使镍-镉电池中镍、镉浸出率分别达到87.6%和86.4%,从而为工业生产提供了科学依据.     

Energy recovery and plume reduction from an industrial spray drying unit using an absorption heat transformer

Spray drying is a widely used unit operation in the chemical industry. It is highly energy intensive, requiring hot, dry airstreams, at temperatures up to 550°C, to dry a wide range of products. Exhaust air from a dryer is usually vented to the atmosphere with little or no heat recovery. At best only the sensible heat associated with the air stream is recovered, although the majority of the stream's energy is in the form of latent heat associated with the evaporated water. Exhaust airstreams usually contain moisture to cause visible plumes upon leaving the dryer stack.A two-stage absorption heat transformer (A.H.T.) has been designed and contructed to investigate the potential for dehumidifying and reheating a simulated dryer exhaust stream to make it suitable for recycling to the dryer inlet. The amount of air vented to atmosphere and also the amount of wasted heat would be reduced by incorporating an A.H.T. into the drying operation. Performance data for the A.H.T. indicates that an airstream can be reheated to a temperature of 160°C, using a lithium bromide solution of 68% w/w, with a circulation ratio (LiBr: steam flow) of 14.8. Temperature lifts between 50 and 70°C are possible in the reheat column when using a low circulation ratio and a high LiBr concentration. Experiments show that a humid air stream can be dehumidified to a level suitable for recycling by direct contact with a concentrated lithium bromide stream.     

Kinetic normal ordering and the 1 + 1 dimensional U(1) anomaly

We consider 1 + 1 dimensional, massless fermions coupled to an external electric field. We show that, contrary to common belief, the computation of the chiral anomaly involves no divergences and no ambiguities. The computation is done in hamiltonian formalism and is based on two steps: (I) the computation of the Schwinger term in the equal time commutator of currents, (II) the physically correct normal ordering with respect to kinetic energy.     

Stereocontrolled metalloenamine alkylations: application to the asymmetric synthesis of 4-alkyl-1,2,3,4-tetrahydroisoquinolines

A procedure for the asymmetric synthesis of 4-alkyl-1,2,3,4-tetrahydroisoquinolines is described. The key step in the synthetic route is a stereocontrolled metalloenamine alkylation using (R)-(+)-phenylglycinol methyl ether as the chiral auxiliary. Subsequent N-methylation, hydrogenolysis and cyclization afforded the target heterocycles with enantiomeric excesses higher than 99%.     

6R- and 6S-6C-Methylmannose from d-mannuronolactone. Inhibition of phosphoglucomutase and phosphomannomutase: agents for the study of the primary metabolism of mannose

The syntheses of 6S-3 and 6R-6 6C-methylmannoses rely on opposite and highly stereoselective reductions of fully and partially protected ketones derived from d-mannuronolactone, respectively. Reduction of the silylated ketone 2 by sodium borohydride was accompanied by complete migration of the silyl protecting group to the new stereogenic centre; the silyl migration was suppressed when the reduction was conducted in the presence of cerium(III) chloride. Both epimers were good inhibitors of phosphoglucomutase and phosphomannomutase, and are specific inhibitors of phosphohexomutases. This work confirms that 6C-alkylhexoses provide a valuable set of compounds with good bioavailability for the study of enzymes involved in the primary metabolism of sugar phosphates. The X-ray crystallographic analysis of 7-deoxy-2,3:5,6-di-O-isopropylidene-α-l-glycero-d-manno-heptofuranose 16 is reported.     

A New Glucoside From Peucedanum ledebourilloides

Peucedanum ledebourilloides, a well-known traditional medicine belonging to Umbell ferace family, used to take the place of Saposhnikovia divaricata to treat arthrits and stop pain et al.