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Objective To systematically summarize the evidence for the effects of martial arts on health and fitness, to show the strengths of different types of martial arts, and to get a more complete picture of the impacts of martial arts on health, and also to provide a basis for future research on martial arts as an exercise prescription in exercise therapy. Method We searched for "martial arts"health" and "random" in eight databases (n= 5432). Randomized controlled trials and controlled clinical trials on the health effects of martial arts were included in the study. Results The final analysis included 28 papers (one general martial arts, one kung fu, sixteen tai chi, six judo, three karate, and one taekwondo). Among the disciplines of martial arts, tai chi was the most well-studied, followed by judo, karate, and taekwondo. Research topics varied widely, and included health, injuries, competition, morals and psychology, and herbal medicine. Most found positive effects on health. Tai chi is no-contact, low-impact, soft body and mindfulness exercise, which has been widely adopted by elderly people and proven to be a beneficial health promotion exercise. Research on judo, karate, and taekwondo mainly focused on improvements to athletes' competitive abilities, rather than on health effects. We did not find any published randomized controlled trials or controlled clinical trials on aikido, kendo, sumo, kyudo, qi gong, or other disciplines. Discussion and Conclusion Since martial arts are widely practiced, their effects on physiology, morphology, immunology, and neurology should be further studied in order to help people to select the best discipline or style to accomplish their purposes. This necessitates categorizing and classifying the disciplines and styles according to their effects on different body systems and levels of contact, as well as standardizing evaluation criteria for martial arts. Martial arts as an exercise prescription can then move from an experience-based to an evidence-based treatment. Language: en

Stable lubrication is very important to the slider/disk interface with the increasing demand on the life of computer hard disk drive (HDD). The inert lubricant perfluoropolyether (PFPE) on the surface of magnetic hard disk is still prone to be catalyzed to decomposition by the slider material Al2O3. The properties of a partial fluorinated hexaphenoxy cyclotriphosphazene, X-1P, are investigated and its function to reduce the catalytic decomposition of PFPE is discussed. The results of contact start–stop (CSS) tester indicate that the thermal stability of the lubricant was greatly improved in the presence of X-1P, and its film thickness has a great influence on the lubrication properties of the HDD.

The transition layer model which is used to account for the viscosity variation in micro-scale gap is presented in this paper. The Reynolds equation based on the model is thus deduced accordingly and numerical simulations are afterwards conducted to analyze the 3D lubrication features. Discussion on the relationships between the pressure and the viscosity of the oil close to the solid walls, velocity of the solid walls, the outlet height, as well as the ratio of transition layer, were conducted. The numerical simulation results show that: 1.the higher the ratio of transition layer was, the greater its influence on the dynamic pressure distribution became; 2. it proved the existence of the transition layer and it could explain the characteristics of the lubricant such as size-effects in micro-scale gap. Consequently, the simulation results accord well with the actual situation, which validates the model. The transition layer model will provide guideline for the analysis of the lubrication properties and future applications such as the design of MEMS/NEMS.

The wetting process and the wetting state transition stages are studied on hydrophilic rough surfaces covered with microscale pillar arrays of different geometrical morphologies and distributions. The effects of geometrical morphology, distribution, parameters, hydrophilicity, and contact angle hysteresis of pillar arrays on wetting state transition are analyzed by energy method. The results indicate that, on the hydrophilic rough surface covered with hexagonal arrays of square pillars, the water droplet tends to stay at a stable Cassie state, or the wetting state transition is only from a Cassie state to an intermediate state. Moreover, smaller pillar interval, larger square pillar width or diameter of cylinder, higher pillar height, strong hydrophilicity are beneficial to the stability of Cassie state, therefore, the wetting state could be prevented from transforming to pseudo-Wenzel state or Wenzel state. However, smaller area fraction of solid-liquid interface under the water drop and weaker hydrophilicity are beneficial to increasing the apparent contact angle. Therefore, the stability of wetting state and the large apparent contact angle should to be considered in hydrophilic surface design. The contact angle hysteresis plays an opposite effect on wetting state stability and the hydrophobicity or superhydrophobicity of rough solid surface. The results provide a theoretical foundation for the design of substrates covered with hydrophilic rough structures, on which the water droplet will obtain a stable Cassie state.

A cryogenic and room-temperature diode pumped Tm,Ho:YVO4 microchip laser with 0.5 mm crystal length lasing around 2 μm is demonstrated for the first time to our knowledge. Under cryogenic temperature of 77K, as much as 1.2 W output and slope efficiency of 35% with respect to absorbed pump power are obtained. At temperature of 5°C the maximum output power of 48mW is obtained at an absorbed pump power of 503 mW, representing a 9.5% optical to optical conversion efficiency. In addition, as much as 8 mW single-frequency output lasing at 2052.6 nm is achieved at room temperature of 15° C.

The adhesive force between microsurfaces is very important to microelectric mechanical system (MEMS), being always a key factor that detemines the energy dissipation and even the life span. In MEMS, the meniscus force mainly depends on the meniscus shape formed between the contact surfaces. This paper analyzes the meniscus shape changes during the seperation of two microsurfaces. Different meniscus shapes were obtained as a result of different hydrophilic/hydrophobic properties, initial liquid heights and separate distances and so on. The fracture height, the meniscus force value and their change rules in different initial conditions are obtained by numerical simulation, which provides a basis of the MEMS performance analysis and life span calculation.