Analytical study on pretensioned bolt-cable combined support of large cross-section tunnel

To study the mechanical responses of large cross-section tunnel reinforced by pretensioned rock bolts and anchor cables, an analytical model is proposed. Considering the interaction between rock mass and bolt-cable support, the strain softening characteristic of rock mass, the elastic-plastic characteristic of bolt-cable support, and the delay effect of installation are considered in the model. To solve the different mechanical cases of tunneling reinforced by bolt-cable support, an analytical approach has been put forward to get the solutions of stress and displacement associated with tunneling. The proposed analytical model is verified by numerical simulation. Moreover, parametric analysis is performed to study the effects of pretension force, cross-section area, length, and supporting density of bolt-cable support on tunnel reinforcement, which can provide references for determining these parameters in tunnel design. Based on the analytical model, a new Ground Response Curve (GRC) considering the reinforcement of bolt-cable support is obtained, which shows the pretension forces and the timely installation are important in bolt-cable support. In addition, the proposed model is applied to the analysis of the Great Wall Station Tunnel, a high-speed railway tunnel with a super large cross-section, which shows that the analytical model of bolt-cable support was a useful tool for preliminary design of large cross-section tunnel.

     

Embedded metal-wire nanograting for a multifunctional optical device

In this paper, an embedded metal-wire nanograting was fabricated and used to construct a multifunctional optical device. The basic function of the nanograting is as a broadband polarizing beam splitter. On the top of the nanograting surface, a homogeneity cladding layer was deposited, and metal wires were deposited in the grating trench. This multifunctional optical device based on the artificial material is designed with a very simple structure, but with the functions of a variable optical attenuator, an optical switch, and a variable optical power splitter. The experimental result as a variable optical power splitter is presented.     

新型 L-乳酸盐酶电极的研制

本文研制一种新型乳酸盐酶生物传感器，此传感器以复合酶ＮＡＤ＋与ＬＤＨ共固定在经ＣＮＢｒ活化的琼脂糖上作为敏感膜。用厚为０３ｍｍ的粒状琼脂糖制成的敏感膜电极，其响应性能最佳。此乳酸盐酶电极测试的最优条件是：在ｐＨ８５的Ｔｒｉｓ－ＨＣｌ缓冲液中进行，温度２５℃，此缓冲液中含１５ｍｍｏｌ·Ｌ－１Ｖｋ３电子介体。此电极的线性反应范围为００４～２１μｍｏｌ·Ｌ－１，每μｍｏｌ·Ｌ－１乳酸盐的敏感度为１３７ｎＡ，工作寿命为１９天。已将此电极用于检测血清中乳酸盐含量，得到满意的结果。