现浇隧道大体积侧墙结构混凝土裂缝控制技术

以控制太湖湖底现浇隧道主体结构大体积混凝土无贯穿收缩性裂缝为目标,基于多场耦合机制抗裂性评估提出了混凝土裂缝控制成套技术。通过掺加具有温升抑制与微膨胀功能的抗裂剂实现混凝土温升和收缩性能的双重调控,采取新型张贴式混凝土保温保湿养护材料实现温降阶段混凝土中心平均温降速率不超过2.0℃/d,内外温差不超过15℃。首件主体结构大体积侧墙自2018年11月浇筑,至今变形监测曲线未出现跳点,实体结构未发现裂缝,裂缝控制效果良好。     

Production optimization,purification, and characterization of a novel acid protease from a fusant by Aspergillus oryzae and Aspergillus niger

The production of a novel acid protease was enhanced by 44 % through statistical optimization. The cultural parameters, such as inoculum size, temperature, moisture content, and incubation time, were 8.59 × 10⁵ g^?1 dry koji, 31 °C, 57 %, and 86 h, respectively. This novel acid protease was purified by 17 folds with a recovery yield of 33.56 % and a specific activity of 4,105.49 U mg^?1. Far-UV circular dichroic spectra revealed that this purified protease contained 7.1 % α-helix, 64.1 % β-sheet, and 32 % aperiodic coil. This novel acid protease was active over the temperature range of 35–55 °C with optimum temperature of 40 °C and was stable in the pH range of 2.5–6.5 with optimum pH of 3.5. Mn²⁺ enhanced its activity while Co²⁺ showed inhibitory effect. With casein as substrate, the kinetic parameters of K _m, V _max, energy of activation (E _a), and attenuation index of inactivation velocity by heat inducing (λ) were 0.96 mg mL^?1, 135.14 μmol min^?1 mg^?1, 64.11 kJ mol^?1, and 0.59, respectively.     

智慧城市基础设施建设与评估

智慧城市基础设施建设是一项基础性、关键性、支撑性的工作,直接决定智慧城市的建设水平及最终成败.首先介绍了智慧城市基础设施所包括的信息网络设施、信息共享基础设施,以及经过智能化改造的传统基础设施的特点,然后针对智慧城市基础设施的建设策略进行了阐述,并提出了整个智慧城市基础设施的发展水平评估指标及其评估要点.     

基于小波特征的配电网线路运行工况识别

配电网线路是用电负荷与变电环节之间的传输介质,及时了解配电网线路的实时运行工况对于保证配电网供电可靠性极其重要。综合考虑现有配电线路工况识别算法的实际应用情况,设计了配电网线路运行工况识别系统,通过线路监测点实时采集了三相电流信号,提出了利用小波分析工具提取信号中的信号标准差、互相关系数以及小波奇异熵相比值3个特征量,采用电磁暂态仿真软件PSCAD/EMTDC建立了配电线路各种常见工况下的特征基因库,并将提取的特征量与特征库的规则相匹配来实现线路工况的识别。应用实例表明,提出的基于小波特征的识别方法具有较好的可靠性和准确性。     

Secondary User Selection Scheme Using Adaptive Genetic Algorithms for Cooperative Spectrum Sensing Under Correlated Shadowing

Cooperative spectrum sensing has been shown to be an effective approach to improve the detection performance by exploiting the spatial diversity among multiple secondary users (or unlicensed users). However, due to correlated shadowing and cooperation overhead in practical cognitive radio networks, it is desired to select an appropriate set of secondary users which have little correlation with each other to participate in cooperation so as to achieve the effective tradeoff between detection performance and cooperation overhead. In this paper, we first study the hypothesis testing model and detection performance of cooperative spectrum sensing under the correlated log-normal shadowing scenario. Afterwards, based on whether the false-alarm and missed-detection probabilities are constrained, three optimization problems are formulated to find the optimal set of secondary users participating in cooperation, which take into account the tradeoff between detection performance and cooperation overhead. Then the solutions using adaptive genetic algorithms are presented for the optimization problems. Finally, simulation experiments demonstrate that our proposed schemes are very effective.     

饮用水源地水污染物的健康风险评价

介绍了健康风险评价方法,并将环境污染的健康风险评价模型引入到饮用水环境评价中,对我国华东地区某城市饮用水源地受污染的饮水途径健康风险率进行了分析与评价.结果表明,化学致癌物对人体健康危害个人年风险度远超过非致癌物.汛期与非汛期的健康风险评价对比表明,汛期应加强对化学致癌物砷和非致癌物氟化物、铅的监控,非汛期应侧重治理氟化物和铁.     

洪水资源利用量研究

提出了洪水资源开发利用原则和评价指标,根据河道水量平衡方程提出计算洪水资源量的洪水资源利用评价方法并对海河流域洪水资源量、已利用洪水资源量和洪水资源利用率进行了计算.结果表明,海河流域洪水资源利用率有逐步提高的趋势.     

偶氮染料分子致癌机理探讨

对国外有关偶氮染料分子致癌的研究结果进行分析,总结出偶氮染料分子致癌的可能途径,为偶氮染料的安全使用和环境友好偶氮染料分子设计提供了理论指导。     

双王金矿床矿化类型问题研究

双王金矿是角砾岩型或是非角砾岩型 .矿化不仅涉及矿床成因问题 ,更直接关系地质找矿 .本文认为“角砾间的可拼性”是“角砾岩”成因解释正确与否的唯一判据 ,据此提出该矿床矿化类型是受含矿岩系变形性质与岩层产状控制的钠长石—含铁碳酸盐网脉状矿化类型 .其矿化类型以网脉状为主 ,次之为平行细脉芾浸染型     

裂缝对预应力混凝土结构耐久性的影响

分析了预应力混凝土结构裂缝状态下力筋腐蚀的机理 ,阐述了裂缝及其宽度与力筋腐蚀间的关系 ,并提出了一般环境条件下预应力筋腐蚀的经时模型 ,可供耐久性设计时参考