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排序方式: 共有903条查询结果,搜索用时 31 毫秒
51.
This paper describes a self-contained integrated microfluidic system that can separate motile sperm from small samples that are difficult to handle using conventional sperm-sorting techniques. The device isolates motile sperm from nonmotile sperm and other cellular debris, based on the ability of motile sperm to cross streamlines in a laminar fluid stream. The device is small, simple, and disposable yet is an integrated system complete with sample inlets, outlets, sorting channel, and a novel passively driven pumping system that provides a steady flow of liquid; it requires no external power source or controls. The device fulfills a need in clinical settings where small amounts of sperm need to be sorted. It also opens the way for convenient bioassays based on sperm motility including at-home motile sperm tests. 相似文献
52.
When a predatory mite, Amblyseius womersleyi is present, Tetranychus kanzawai takes refuge on its webs during a quiescent stage. To examine the factors responsible for the antipredator behavior of T. kanzawai, we exposed T. kanzawai to the odor of conspecifics, A. womersleyi, and both T. kanzawai and A. womersleyi. The proportion of T. kanzawai females that took refuge was significantly higher when they were exposed to the odor of `both T. kanzawai and A. womersleyi.' Furthermore, the proportion of T. kanzawai females that took refuge was significantly higher when they were exposed to injured conspecifics than to intact conspecifics. These results suggest that T. kanzawai assesses predation risk, at least in part, by using the odor of injured conspecifics. 相似文献
53.
Water-repellent surfaces were fabricated on blend sheets of poly(l-lactic acid)/poly(butylene succinate) with various blending ratios by the successive processing; (1) plasma etching, followed by (2) the hydrophobic plasma polymer coating. Rough morphology was formed effectively on the mosaic structured surface of blend sheets via the oxidative etching, and advanced water repellency was achieved after the thin membrane coating was synthesized with a hydrophobic plasma polymer coating by use of hexamethyldisiloxane or hexamethyldisilazane. High water repellency is expressed through the columnar hair-like structured model, where the air-water surface interaction in the voids is taken into account. 相似文献
54.
55.
The effects of a proposed combustion technique, named as annular counterflow, on the enhancement of jet diffusion flame blowout limits were investigated by a series of experiments conducted for the present study. Annular counterflow was formed in a concentric annulus, in which fuel jet was ejected from a nozzle and air was sucked into an outer cylinder encompassing the nozzle. Three fuel nozzles and outer cylinders of different sizes were utilized to perform the experiments. Schlieren technique and normal video filming were employed for the visualization of diverse flame morphologies triggered by the said flow. Gas samplings were taken and scrutinized by the use of a gas chromatograph. Results showed that the blowout limits can be enhanced dramatically by an increase in volume flow rates of air‐suction. Mixing enhancement is achieved with frequent and strong outward ejection of fluids from the cold jet when this technique is applied. The blowout limits are further extended when the diameter of outer cylinders becomes smaller and/or that of the fuel nozzle becomes larger. The base widths of lifted flames were found to be narrower in the interim of annular counterflow application. The rates of increase in flame lift‐off heights and base widths along with an increase in fuel flow velocities become sluggish when the volume flow rates of air are increased. The amount of fuel that was sucked into the outer cylinder was found to be negligible and trivial. A model based on annular and coaxial jet was developed to predict the lifted flame base width and blowout limits. The coincidence between the prediction and experimental results unambiguously validates that the momentum of air‐suction dominates the beneficial effect. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
56.
Minoru Kumakura Isao Kaetsu Kazuhiro Asami Shuichi Suzuki 《Journal of Materials Science》1989,24(5):1809-1813
Porous polymer composite columns having porous structure were prepared by radiation cast-polymerization of hydrophilic monomers at low temperature and their characteristics were studied. The porosity of the polymer increased with decreasing monomer concentration. The elution time of water in the polymer column increased with increasing monomer concentration and with decreasing irradiation temperature. The elution time was dependent on the degree of hydration of the polymer. The polymer with a degree of hydration of 0.2 to 0.4 gave the minimum elution time. The elution time decreased with the addition of porous inorganic substances. 相似文献
57.
Norimasa Nukaga Hirofumi Ono Takuya Shida Hideaki Machida Toshie Suzuki Hiroshi Funakubo 《组合铁电体》2013,141(1):215-222
SrBi 2 Ta 2 O 9 thin films were prepared by ECR plasma enhanced metalorganic chemical vapor deposition (ECR-MOCVD) with a liquid-delivery system using one cocktail source without an additional solvent. The strontium-tantalum double alkoxide, Sr{Ta[OC 2 H 4 H(CH 3 ) 2 ](OC 2 H 5 ) 5 } 2 , was dissolved in stabilized trimethyl bismuth, Bi(CH 3 ) 3 / dioxane. This source system has been used in a conventional bubbling system. Deposition rate and the composition of the films were strictly controlled by the concentration and the composition of the cocktail source. Therefore, high reproducibility was realized by using this system. The constituent phase of the stoichiometric SBT film as-deposited at 500 C on a (111)Pt/TiO 2 /SiO 2 /Si substrate was a fluorite phase and transformed to the single phase of SBT by the post annealing at 800 C. It showed almost the same ferroelectricity as the stoichiometric composition film. 相似文献
58.
Kouichi Asakura Ayuko Iida Ryoichi Kitagata Atsushi Yoshida Shuichi Osanai Akihiro Kuroda 《Journal of surfactants and detergents》2001,4(4):375-378
Adsorption properties of two types of dimethylpolysiloxane backbone derivatives, perfluoroalkyl polyoxyethylenated dimethylpolysiloxane
(FPD) and polyoxyethylenated dimethylpolysiloxane (PD), onto keratin surfaces were investigated. Both polymers are amphiphilic,
since they possess hydrophilic polyoxyethylene groups. FPD contains a perfluoroalkyl group that provides both water-and oil-repellent
properties, whereas PD lacks these groups. Adsorption properties of these polymers onto keratin surfaces are considered a
good index to evaluate these compounds as nonionics used in hair-coating agents, since keratin is a major component of hair.
FPD was more likely to be adsorbed and less likely to be eliminated from the keratin surface than PD. Once FPD had been adsorbed
onto the keratin surface, it was very slowly washed from the surface when it was immersed in stationary water, whereas PD
polymers were quickly washed from the keratin surface. Even in running water, rapid elimination of FPD was not observed. The
strong resistance to loss of FPD after washing with a large quantity of water may be due to the water-repellent nature of
the perfluoroalkyl groups. As a comparison, FPD adsorption onto a glass surface was also investigated. The affinity to the
glass surface was found to be less than to the keratin surface. 相似文献
59.
The elements added diamond-like carbon films (hydrogen, fluorine, and sulfur) fabricated from C2H2:H2, C2H2:CF4 and C2H2:SF6 mixtures were used to compare and study the effects of element contents on the deposition and tribological properties of films prepared by plasma-based ion implantation (PBII). The structure of the films was analyzed by Raman spectroscopy. Hardness and elastic modulus of films were measured by nano-indentation hardness testing. Contact angle and surface energy of films were measured by contact angle measurement. Tribological characteristics of films were performed using a ball-on-disk friction tester. The results indicate that with the increasing element contents, the hardness and elastic modulus, and surface energy of all films decreases, while the surface angle tends to increase. Additionally, H-DLC films at C:H flow rate ratio of 1:4 shows a friction coefficient of 0.08 under ambient air, which are considerable improvement in the tribological properties. This is due to the formation of a transfer films on the interface and high hydrogen contents. For F-DLC films and S-DLC films, does not show a significant decrease in the friction coefficient with the fluorine and sulfur contents under ambient air. The decrease in the friction coefficient is greater under high vacuum than under ambient air. 相似文献
60.
Naoki Uchida Yoshie Maitani Yoshiharu Machida Masayuki Nakagaki Tsuneji Nagai 《Drug development and industrial pharmacy》1991,17(12):1625-1634
The nasal drug absorption and the effect of absorption promoters have been studied in rabbits. Nasal mucosa excised from rabbits was mounted as a flat sheet in an in vitro chamber. The result indicates that the change in the porosity of the membrane by pretreatment with bile salts increased the permeability coefficient of sodium chloride in the nasal membrane. The permeabilities of dextran derivatives were enhanced by pretreatment with sodium glycocholate (GC). The permeability coefficient (P) of fluorescein isothiocyanate diethylaminoethyl dextran 相似文献