Unique CNTs-chained Li4Ti5O12 nanoparticles as excellent high rate anode materials for Li-ion capacitors

Composite anode materials with a unique architecture of carbon nanotubes (CNTs)-chained spinel lithium titanate (Li₄Ti₅O₁₂, LTO) nanoparticles are prepared for lithium ion capacitors (LICs). The CNTs networks derived from commercial conductive slurry not only bring out a steric hindrance effect to restrict the growth of Li₄Ti₅O₁₂ particles but greatly enhance the electronic conductivity of the CNTs/LTO composites, both have contributed to the excellent rate capability and cycle stability. The capacity retention at 30 C (1 C = 175 mA g^?1) is as high as 89.7% of that at 0.2 C with a CNTs content of 11 wt%. Meanwhile, there is not any capacity degradation after 500 cycles at 5 C. The LIC assembled with activated carbon (AC) cathode and such a CNTs/LTO composite anode displays excellent energy storage properties, including a high energy density of 35 Wh kg^?1 at 7434 W kg^?1, and a high capacity retention of 87.8% after 2200 cycles at 1 A g^?1. These electrochemical performances outperform the reported data achieved on other LTO anode-based LICs. Considering the facile and scalable preparation process proposed herein, the CNTs/LTO composites can be very potential anode materials for hybrid capacitors towards high power-energy outputs.     

放顶煤液压支架在土耳其IMABT煤矿现场的应用

通过对土耳其IMBAT煤矿地质条件的分析研究，结合多种选型计算方法的验证，最终选择了合适的设备，使该矿的开采效率得到较大提升。同时也扩大了我国的煤炭开采装备应用范围。根据在土耳其IMBAT煤矿现场多年的服务经验，将理论与实践相结合，就综采放顶煤液压支架在土耳其IMABT煤矿现场的应用进行了论述。     

高预应力高强度锚索支护在深井高应力巷道的应用

以红四煤矿深井高应力巷道支护为例,在研究地应力状态、围岩强度、岩石成分的前提下,通过数值模拟方式确定了高预应力高强度高刚度锚杆锚索联合支护方案。通过对试验巷道变形移近量监测发现,两帮移近变形呈稳定状态的时间提前,巷道顶底板变形状况有所改善。     

孤岛工作面撤出支架时的顶板加固及撤出工艺

11210高水充填工作面作为孤岛工作面,末采阶段顶板压力大。采用锚网支护控制工作面顶板,撤架时利用掩护架保证撤架空间安全,利用移架平台撤出剩余支架,实现了安全生产。     

Practices,projects and portfolios: Current research trends and new directions

Project portfolio management (PPM) bridges strategy and project management. Traditional research in PPM has primarily investigated the rational, top-down and structural aspects of strategizing. By doing so, it has failed to focus on the underlying practices that are triggered by the strategy and how these practices frame strategy implementation. Practice-based research provides a methodological lens to explore the reality of strategic enactment through the project portfolio. Practice-based perspectives are under-represented in PPM research; therefore the aim of this paper is to provide an agenda for further practice-based research in PPM. Central to this agenda is a concern with various aspects of practice, including its discursivity, representation, dynamic capabilities, leadership and materiality.     

Test sample allocation method for testability verification test

An extended failure mode effect and criticality analysis (FMECA)-based sample allocation method for testability verification is presented in this study to deal with the poor representativeness of test sample sets and the randomness of the testability evaluation results caused by unreasonable selection of failure samples. First, the fault propagation intensity is introduced as part of the extended information of FMECA, and the sample allocation impact factors of component units and failure modes are determined under this framework. Then, the failure mode similarity and impact factor support are defined, and the game decision method for weighing the relationship between similarity and support is proposed to obtain the weight of failure mode impact factor. Finally, a two-step allocation framework of test samples is formulated to realize the sample allocation of component units and failure modes. This method is applied to the testability verification test of a launch control system. Results show that this method can obtain more representative test samples compared with the traditional sample allocation method while effectively reducing randomness of single testability evaluation result.     

火成岩侵入区煤层巷道支护方案数值模拟分析

本文以永定庄矿3-5^#层盘区皮带巷为研究对象,针对火成岩侵入区掘进顶板易冒落、锚索锚固效果差等工程问题,对破碎全煤巷进行了支护设计。根据火成岩侵入区巷道优化设计试验段的实际工程情况,建立了合理的数值模型,对掘进期间巷道的支护效果进行模拟分析,确定了最优的巷道支护方案。     

8809工作面过空巷覆岩失稳规律及围岩控制技术研究

为保障8809工作面推进过空巷区域的安全生产,通过对过空巷区域时覆岩变形规律的分析,得出工作面与未支护的空巷间煤柱宽度为14m时,空巷围岩出现失稳。基于分析结果,确定J09-01和J09-02空巷采取锚网索+工字钢梁的支护技术,J09-03和J09-04空巷采用预充填技术,工作面顺利通过补强支护和充填空巷区域。     

半纤维素基阿维菌素载药微囊的制备及性能

目前阿维菌素以高效性、无污染和低抗药性等特点而得到广泛应用，但是其稳定性较差，易降解导致使用量较大从而造成浪费。为解决上述问题，本文以半纤维素为基体，利用原位聚合法制备阿维菌素载药微囊（HDCM），通过制备条件、热降解性、储存稳定性和释放动力学研究，确定了HDCM的载药量、热稳定性及释放性能。结果表明，在芯壁比为1∶34（质量比），温度为65℃，pH为3.5的制备条件下，HDCM的载药量可达66.5%，粒径较小且分散均匀。HDCM的热降解性能和恒温热稳定性能较阿维菌素原药有所提高，最高热分解温度从261℃增加到272℃，阿维菌素原药10h后降解率达到12.1%，而载药量为66.5%的HDCM降解率仅为5.2%。HDCM的释放机理满足Fick扩散，阿维菌素原药在水中的累积释放率在12h之内达到83.8%，而HDCM的累积释放率在24h之后才有所增大，12h内其释放率仅为33.7%，表明HDCM具有极好的缓释性能。