关于三峡库区周边坡体岩石特性的考察

岩石强度的载荷速率相关性与岩石的时间相关性特性及粘弹性性质密切相关，而且强度的栽荷速率相关性越大，越容易发生蠕变破坏。对于坡体来说，如果构成坡体的岩石的时间相关性很显著．那么即使在比较低的应力下仅施加一点载荷，也容易发生变形。针对三峡库区周边滑坡多发，采集了组成滑坡坡体的4类主要岩石-泥岩、灰岩、泥质砂岩及砂岩。通过室内岩石力学强度试验，获得了不同岩石的强度特性曲线及表示载荷速率相关性的参数n。利用一个试件通过载荷速率交替变换获得了不同应变速率下的应力-应变曲线，从而根据强度的变化率不仅获得了峰值强度的载荷速率相关性，而且还求得了残余强度的载荷速率相关性。在单轴压缩试验中，残余强度的n值与峰值强度的n值有较大的差异，但在三轴压缩试验中两者的差异却不太明显。而且在气干状态下，不管是峰值强度还是残余强度的n值均随着围压的增加而增加。     

适用于小型岩石试件的三轴压缩试验技术与设备的开发及其应用

为了用有限的岩石试样在室内进行大量的岩石力学试验测试，对直径10mm、长度20mm的小型岩石试件进行开发、制作。同时对S．Okubo等（2002）开发的透明围压容器进行改进，其围压可达10MPa左右。用此改进的试验设备对小型岩石试件进行三轴压缩试验。通过对田下凝灰岩的试验，由小型试件得到的力学参数——黏聚力和内摩擦角，与用常规试件获得的试验结果相一致。而且在载荷速率交替变换的试验中，用一个小型试件就可获得应力一应变曲线的载荷速率相关性。通过对三峡库区周边滑坡地带采集的岩石试样的测试，成功获得不同岩石的强度特性曲线及表示载荷速率相关性的参数。     

A design and simulation tool for ground source heat pump system using energy piles with large diameter

Calculation of the underground temperature resulting from heat injection/extraction into/from ground heat exchangers (GHEXs) with hourly variation is one of the most noteworthy challenges to address when simulating and designing a ground source heat pump (GSHP). In order to overcome this challenge, the authors introduce a method to calculate the underground temperature, by considering heat injection/extraction into/from GHEXs with hourly variation. The method applies the superposition of the infinite cylindrical source (ICS) solution and the infinite line source (ILS) solution to calculate the temperature change due to heat injection/extraction into/from the considered GHEX and other neighboring GHEXs, respectively. The calculation method also considers heat injection/extraction from GHEXs with different heat injection/extraction rates and is able to accommodate GHEXs with large diameters such as energy piles. The calculation method was evaluated by applying it to calculate the temperature variation of the heat carrier fluid in a GSHP system with energy piles.     

Application of laser flash method to penetrative materials for measurement of thermal diffusivity

The theoretical equation for the laser flash method is derived where the penetration and transmission of the input energy into the test piece is taken into account. The thermal diffusivity of penetrative materials and its measurement errors are calculated instantly by fitting the experimental data to this equation by using the method of least squares with an on-line personal computer connected to the laser flash device. The usefulness of this method is shown by comparing it with the conventional method.     

Anthocyanins,but not Anthocyanidins,from Bilberry (Vaccinium myrtillus L.) Alleviate Pruritus via Inhibition of Mast Cell Degranulation

Abstract: We have previously reported that bilberry anthocyanins exhibit an anti‐pruritic effect in a mouse model of allergic contact dermatitis. It has been reported that anthocyanins are particularly sensitive to thermal treatment and are easily hydrolyzed to anthocyanidins when exposed to high temperatures. The objective of this study was to compare the anti‐pruritic effect of anthocyanin‐rich quality‐controlled bilberry extract and anthocyanidin‐rich degraded extract using a mouse model of allergic contact dermatitis. BALB/c mice with allergic contact dermatitis induced by 4 weeks of repeated application of 2,4,6‐trinitro‐1‐chlorobenzene (TNCB) were administered Bilberon‐25 orally for 4 weeks after sensitization with TNCB. The effect of Bilberon‐25 on pruritus was evaluated by measurement of scratching behavior. RBL‐2H3 mast cells were used to investigate the effect of Bilberon‐25 on degranulation in 48/80‐stimulated mast cells. Compared with nonheated Bilberon‐25, the proportion of anthocyanins in heated Bilberon‐25 decreased, and the proportion of anthocyanidins was increased in heated‐time dependent manner. Treatment with non‐heated Bilberon‐25 significantly attenuated the TNCB‐induced increase in scratching behavior, whereas treatment with 2 h‐heated Bilberon‐25 did not. Moreover, 300 μg/mL nonheated Bilberon‐25 showed significant inhibition of degranulation in RBL‐2H3 mast cells, whereas 2 h‐heated Bilberon‐25 had no effect at any concentration studied. It is assumed that the inhibitory effect of bilberry anthocyanins on pruritus might be mediated, at least in part, by its inhibitory effect on mast cell degranulation. In conclusion, the anthocyanin‐rich but not anthocyanidin‐rich bilberry extract may be a useful dietary supplement for skin diseases involving pruritic symptoms, such as chronic allergic contact dermatitis, atopic dermatitis, and rhinitis.     

开挖扰动区内岩石的压密特性和强度恢复性研究

 利用交替变换荷载速率试验研究压密后岩石试样的强度恢复和荷载速率依存性。首先,分别对田下凝灰岩、来待砂岩、河津凝灰岩和三城目安山岩4种岩石试样在空心圆筒内进行压缩破坏,然后持续轴向加载,压密破坏后的岩石试样。从空心圆筒中推出压密后的试样,进行单轴压缩下的交替变换荷载速率试验,即按一定应变或位移间隔,对同一试样交替施加高低2种不同的荷载速率,得到对应于2种荷载速率的应力–应变曲线。在整个交替变换荷载速率试验过程中,应力随荷载速率的切换而增减。从交替变换荷载速率试验得到的应力–应变曲线上的荷载速率切换点出发,利用3次样条曲线拟合得到2条对应于高低2种荷载速率的应力–应变曲线,并求解强度点处荷载速率依存性参数n。试验结果表明,田下凝灰岩、来待砂岩和河津凝灰岩的强度恢复现象明显,单轴抗压强度随着压密试验中轴向最大荷载的增加而增加,但没有观察到三城目安山岩的强度恢复现象。当压密试验中的最大轴向荷载较大时,压密后的试样的荷载速率依存性与完整试样的基本一致。当压密试验中的最大轴向荷载较小时,从极大和极小2个方面求解荷载速率依存性参数n,得出完整试样的n值介于压密试样的极大值 和极小值 之间,且差值不大。研究结果表明,在进行适当支护之后,随着时间的推移,开挖扰动区内的岩石存在强度恢复的可能性,且今后利用数值模拟考虑开挖扰动区内的岩石强度恢复特性和时间依存性时,在本构方程中可以采用与完整围岩区域一样的参数,从而简化数值模拟程序。     

Electro-mechanical coupling in ionic gels

An ionic-polymer–metal-composite film shows electro-mechanical coupling. When the film is bent, electric current is induced. Measurement of the induced current indicates that the current depends on the speed of bending, but the total amount of the charge transferred across the film is independent of the speed, and depends only on the magnitude of the bending. The result indicates that in addition to previously proposed dynamical coupling effect, there is a static electro-mechanical coupling effect. Mathematical model is proposed to describe this phenomena.     

Brain activity in the resting state: default mode network as an inside story within the brain

As a promising research field after the turn of the new century, a default mode network (DMN) in the brain shows strong potential as a new breakthrough in neuroscience. This approach emphasizes the baseline of the brain’s activities when the brain is awake but is not receiving any external input signal. The study of DMN has recently been highlighted, and is expected to provide a key to understanding mental disorders. This article consists of two sections: (1) a brief tutorial on DMN is presented, together with some necessary fundamental knowledge of neuroscience, and (2) a framework of network informatics for the DMN is proposed based on network dynamics. Models of information networks are discussed to bridge the gap between the level of regions and the level of neurons in the brain, and major issues about analyzing the DMN by brain imaging technologies are also discussed. One of the inspirations arising from the DMN approach is how spontaneous collective behavior emerges within an autonomous system. This is crucial to a systematic understanding of the brain’s function, and to exploring some new design principles of autonomous robotics in order to demonstrate complex life-like behaviors in engineering.     

Decay of material properties of degraded MEA caused by repeated cold starts under subzero conditions in polymer electrolyte fuel cells

This study investigated the characteristics of cell performance degradation, decline of component performance, and changes in the properties of membrane electrode assembly materials caused by repeated cold starts under a subzero condition of ?30 °C. It was made clear that functional decay appeared mainly at the cathode due to increased proton conductive impedance and reduction of reactivity of the electrode catalyst. Among the cathode components, an increase in proton conductive impedance in the cathode electrolyte was dominant. Furthermore, the application of ion chromatography and a newly developed proton‐induced gamma‐ray emission method to measure fluorine in the off‐gas drain revealed that decomposition of the electrolyte was dominant in the cathode catalyst layer. A decrease in fluorine in the cathode electrolyte measured by fluorine‐19 nuclear magnetic resonance confirmed this decomposition. A hypothesis is also presented concerning the cause of the performance degradation. © 2012 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library ( wileyonlinelibrary.com/journal/htj ). DOI 10.1002/htj.20394     

Application of SPRT to an image data sequence for a remote monitoring system

Recently, remote monitoring camera systems have been widely used for security. In such systems, one important function is that the system automatically detects any change in the scenes from the monitoring cameras. In wireless remote monitoring camera systems, the images of the scenes are generally transmitted as compressed data (e.g., JPEG file), because of the capacity of the wireless channel. This article shows the automated detection of the change point in time-series data of compressed JPEG file quantity (Kbytes) from the monitoring camera by applying the sequential probabilistic ratio test (SPRT) and the Chow test, which is well known as a standard method for detecting structural change in time-series data.