水性闪光底漆的制备与性能研究

采用水性聚丙烯酸或水性聚氨酯作为成膜基料,与水性闪光颜料、各种涂料添加剂等配制底漆。讨论了树脂和助剂的种类及其配比对颜料颗粒取向的影响。对涂膜的机械性能、闪光效果以及视觉丰满度、流平性、稳定性等的检测结果表明,漆膜具有良好的性能。     

Thermal aggregation of whey proteins in the presence of buttermilk concentrate

The objective of this study was to assess the impact of adding buttermilk concentrate to the denaturation and microparticulation process of cheese whey protein concentrate. For this purpose, the two concentrates were mixed and co-denatured (pH 4.6, 90 °C,) and homogenized. The presence of buttermilk significantly increased aggregation yield and decreased water-holding capacity of aggregates up to a buttermilk:whey protein ratio of 75:25. Modification of rheological properties suggests that denatured whey protein interacted with casein. A thiol blocker, N-ethylmaleimide, was added before heating to measure the role of disulphide bond formation in the aggregation process. Results showed that both covalent and non-covalent interactions were involved in aggregate formation. Ultrasound treatment was applied during denaturation process and was shown to influence aggregate formation. It appeared that under increased turbulence and cavitation conditions, aggregation yield was increased and water-holding capacity decreased.     

Tribological properties of fluid phase phospholipid bilayers

Our recent studies showed that solid phase phospholipid bilayers play an important role in joint lubrication mechanism. We investigate the tribological properties of fluid phase bilayers depending on various experimental parameters. Bilayers containing a fluorescent lipid with a large head-group and surfaces covered with only one bilayer poorly lubricate meaning that the slip plane during shear is located in the thin aqueous layer between the bilayers. Lubrication and resistance to normal and tangential stresses are greatly improved in buffered saline solution. Bilayers prepared by vesicle fusion method improve the tribological properties of even very rough substrates by smoothing their topographical defects.     

Ionic liquid droplet as e-microreactor

A powerful approach combining a droplet-based, open digital microfluidic lab-on-a-chip using task-specific ionic liquids as soluble supports to perform solution-phase synthesis is reported as a new tool for chemical applications. The negligible volatility of ionic liquids enables their use as stable droplet reactors on a chip surface under air. The concept was validated with different ionic liquids and with a multicomponent reaction. Indeed, we showed that different ionic liquids can be moved by electrowetting on dielectric (EWOD), and their displacement was compared with aqueous solutions. Furthermore, we showed that mixing ionic liquids droplets, each containing a different reagent, in "open" systems is an efficient way of carrying supported organic synthesis. This was applied to Grieco's tetrahydroquinolines synthesis with different reagents. Analysis of the final product was performed off-line and on-line, and the results were compared with those obtained in a conventional reaction flask. This technology opens the way to easy synthesis of minute amounts of compounds ad libitum without the use of complex, expensive, and bulky robots and allows complete automation of the process for embedded chemistry in a portable device. It offers several advantages, including simplicity of use, flexibility, and scalability, and appears to be complementary to conventional microfluidic lab-on-a-chip devices usually based on continuous-flow in microchannels.     

Characterization of microlenses by digital holographic microscopy

We demonstrate the use of digital holographic microscopy (DHM) as a metrological tool in micro-optics testing. Measurement principles are compared with those performed with Twyman-Green, Mach-Zehnder, and white-light interferometers. Measurements performed on refractive microlenses with reflection DHM are compared with measurements performed with standard interferometers. Key features of DHM such as digital focusing, measurement of shape differences with respect to a perfect model, surface roughness measurements, and optical performance evaluation are discussed. The capability of imaging nonspherical lenses without any modification of the optomechanical setup is a key advantage of DHM compared with conventional measurement tools and is demonstrated on a cylindrical microlens and a square lens array.     

Ultra-high-density phase-change storage and memory

Phase-change storage is widely used in optical information technologies (DVD, CD-ROM and so on), and recently it has also been considered for non-volatile memory applications. This work reports advances in thermal data recording of phase-change materials. Specifically, we show erasable thermal phase-change recording at a storage density of 3.3 Tb inch(-2), which is three orders of magnitude denser than that currently achievable with commercial optical storage technologies. We demonstrate the concept of a thin-film nanoheater to realize ultra-small heat spots with dimensions of less than 50 nm. Finally, we show in a proof-of-concept demonstration that an individual thin-film heater can write, erase and read the phase of these storage materials at competitive speeds. This work provides important stepping stones for a very-high-density storage or memory technology based on phase-change materials.     

Adhesion of Thermal Oxide Scales on Hot-Rolled Conventional and Recycled Steels

The mechanical adhesion of thermally-formed oxide scales formed on industrial hot-rolled low carbon steel strips produced through the blast-furnace route (conventional steel) or the electric-arc-furnace route (recycled steel) was studied. A new macro-tensile test was compared to a micro-tensile test previously used. It was observed that spallation of scales during straining increased with increasing the tensile strain rate. A higher strain rate resulted in a lower strain inducing the first spallation. As a result, the mechanical adhesion energy of scales actually formed on the recycled steel was in the range 300–700 J m^?2. Comparison at the same strain rate of the conventional and recycled steels showed higher scale adhesion for the recycled steel due to the presence of high amounts of interfacial silica.     

Approximate analysis of production systems operated by a CONWIP/finite buffer hybrid control policy

We present a decomposition method for approximate performance analysis of tandem production systems that are controlled by a hybrid control policy, in which the finite buffers of a flow line are augmented by a CONWIP cell enforcing release control to the line. The method decomposes the system into a set of three different types of building blocks. One is the continuous material two-machine line described in the literature; the second is a special case of the first in which the buffer is infinite. The third type of building block is a synchronization stage that is described and analyzed in this paper. Using these building blocks, we represent both the flow of material and the flow of information in the system. We derive new decomposition equations to relate the parameters of the building blocks. An iterative algorithm is constructed to determine the values of the parameters and to estimate the performance measures of the system. It has been observed to be fast and accurate for a large class of systems.     

Control of upper limb prostheses: terminology and proportional myoelectric control-a review

The recent introduction of novel multifunction hands as well as new control paradigms increase the demand for advanced prosthetic control systems. In this context, an unambiguous terminology and a good understanding of the nature of the control problem is important for efficient research and communication concerning the subject.     

Possible influence of surfactants and proteins on the efficiency of contact agar microbiological surface sampling

Agar contact microbiological sampling techniques, based on a transfer of the microorganisms present on a surface to a culture medium, are widely used to assess and control surface cleanliness and to evaluate microbial contamination levels. The effectiveness of these techniques depends on many environmental parameters that influence the strength of attachment of the bacteria to the surface. In the present study, stainless steel and high density polyethylene surfaces were inoculated with known concentrations of Staphylococcus epidermidis. Following an experimental design, the surfaces were sampled with different types of replicate organism direct agar contact plates and Petrifilm; results indicated that recovery rates were influenced by the presence of egg white albumin or Tween 80 in the inoculum solutions or by the introduction of surfactants into the contact agar of the microbiological sampling techniques. The techniques yielded significantly different results, depending on sampling conditions, underlining the need for a standardization of laboratory experiments to allow relevant comparisons of such techniques.