Guiding of 150 keV O^(6+) ions through nanocapillaries in an uncoated Al_2O_3 membrane:special time dependence of the transmission profile width

This paper reports that the transmission of O6＋ ions with energy of 150keV through capillaries in an uncoated Al2O3 membrane was measured, and agreements with previously reported results in general angular distribution of the transmitted ions and the transmission fractions as a function of the tilt angle well fitted to Gaussian-like functions were observed. Due tousing an uncoated capillary membrane, our φc is larger than that using a gold-coated one with a smaller value of Ep/q, which suggests a larger equilibrium charge Q∞ in our experiment. The observed special width variation with time and a larger width than that using a smaller Ep/q were qualitatively explained by using mean-field classical transport theory based on a classical-trajectory Monte Carlo simulation.

Comparative investigation towards machinability improvement in hard turning using coated and uncoated carbide inserts： part Iexperimental investigation

The investigation of low cost uncoated andcoated carbide insert in the hard turning of hardened AISID2 steel （≥55 HRC） will definitely open up a new arena asan economical alternative suitable to industrial machiningsectors. Thus, this paper reports the comparative machin-ability assessment for the hard turning of AISI D2 steel（（55 ± 1） HRC） by coated and uncoated carbide insert in adry environment. Micro hardness and abrasion tests werecarried out to assess resistance capability against wear. Theabove test results confirmed the greater wear resistanceability of AIaO3 coated carbide insert over uncoated car-bide. Based on the extensive investigation of comparativemachinability, the coated carbide insert （TiN-TiCN-A12O3）outperformed the uncoated carbide insert with regard tosurface roughness, flank wear, chip-tool interface temper-ature, and chip morphology. Abrasion and diffusion wereobserved as the principal tool wear mechanisms in theinvestigated range. The uncoated carbide failed completelydue to the severe chipping and quick dulling of the cuttingedge, which led to its unsuitability for machining hardenedsteel.

Influence of Machining Parameter on Surface Roughness and Tool Life While Machining EN24 Grade Alloy Steel

The requirements of high quality machined surface as well as demand of enhanced contact time of cutting tools drive towards adopting multilayer coated carbide inserts. The industry requires higher productivity, hence higher machining parameters need to be used in order to meet the industry requirements. The alloy steel material used to fabricate machine parts consists of alloying elements like nickel, chromium and molybdenum difficult to machine, since the cutting tool fails by high tool wear, if we use uncoated carbide inserts to machine alloy steels. Hence in the present research work it is intended to use tungsten carbide inserts coated with different coatings for the experiments. The turning experiments were carried out using different grades of uncoated and coated carbide inserts of identical tool signature. The cutting speed selected for the experiments was 100 to 500 m/min in steps of 100 m/min, and the feed per revolution was 0.1 mm to 0.4 mm in step of 0.1 mm. The experimentation was carried out following ISO3685 standards. The results of the experiments revealed that the surface roughness measured was the least at cutting speed 500 m/min and feed per revolution of 0.1 mm, however the chip breaking found better when the feed used was greater than 0.2 mm/revolution.

Molecular mechanism of SCARB2-mediatec attachment and uncoating of EV71

Unlike the well-established picture for the entry of enveloped viruses, the mechanism of cellular entry of non-enveloped eukaryotic viruses remains largely mysterious. Picornaviruses are representative models for such viruses, and initiate this entry process by their functional receptors. Here we present the structural and functional studies of SCARB2, a functional receptor of the important human enterovirus 71 （EV71）. SCARB2 is responsible for attachment as well as uncoating of EV71. Differences in the structures of SCARB2 under neutral and acidic conditions reveal that SCARB2 undergoes a pivotal pH-dependent conformational change which opens a lipid-transfer tunnel to mediate the expulsion of a hydrophobic pocket factor from the virion, a pre-requisite for uncoating. We have also identified the key residues essential for attachment to SCARB2, identifying the canyon region of EV71 as mediating the receptor interaction. Together these results provide a clear understanding of cellular attachment and initiation of uncoating for enteroviruses.

Multiple Roles of HIV-1 Capsid during the Virus Replication Cycle

Human immunodeficiency virus-1 capsid(HIV-1 CA) is involved in different stages of the viral replication cycle. During virion assembly, CA drives the formation of the hexameric lattice in immature viral particles, while in mature virions CA monomers assemble in cone-shaped cores surrounding the viral RNA genome and associated proteins. In addition to its functions in late stages of the viral replication cycle, CA plays key roles in a number of processes during early phases of HIV-1 infection including trafficking, uncoating, recognition by host cellular proteins and nuclear import of the viral preintegration complex. As a result of efficient cooperation of CA with other viral and cellular proteins, integration of the viral genetic material into the host genome, which is an essential step for productive viral infection, successfully occurs. In this review, we will summarize available data on CA functions in HIV-1 replication, describing in detail its roles in late and early phases of the viral replication cycle.