Adaptive feature selection method for action recognition of human body in RGBD data

目前在RGBD视频的行为识别中,为了提高识别准确率,许多方法采用多特征融合的方式。通过实验分析发现,行为在特定特征上的分类效果好,但是多特征融合; 并不能体现个别特征的分类优势,同时融合后的特征维度很高,时空开销大。为了解决这个问题,提出了; RGBD人体行为识别中的自适应特征选择方法,通过随机森林和信息熵分析人体关节点判别力,以高判别力的人体关节点的数量作为特征选择的标准。通过该数量; 阈值的筛选,选择关节点特征或者关节点相对位置作为行为识别特征。实验结果表明,该方法相比于特征融合的算法,行为识别的准确率有了较大提高,超过了大部; 分算法的识别结果。Many methods adopt the technique of multi-feature fusion to improve the; recognition accuracy of RGBD ideo. Experimental analyses revealed that; the classification effect of certain behavior in some features is good;; however, multi-feature fusion cannot reflect the classification; superiority of certain features. Moreover, multi-feature fusion is; highly dimensional and considerably expensive in terms of time and; space. This research proposes an adaptive feature selection method for; RGBD human-action recognition to solve this problem. First, random; forest and information entropy were used to analyze the judgment ability; of the human joints, whereas the number of human joints with high; judgment ability were chosen as the feature selection criterion. By; screening the threshold number, either the joint feature or the relative; positions of the joints was used as the recognition feature of action.; Experimental results show that compared with multi-feature fusion, the; method significantly improved the accuracy of action recognition and; outperformed most other algorithms.国家自然科学基金项目; 福建省自然科学基金项目; 中医健康管理福建省2011协同创新中心项

高藻饮用水系统中羟基自由基降解诺氟沙星

在厦门翔安水厂12000t/d常规饮用水处理工艺的基础上建立了\"混凝沉淀-砂滤-·OH/NaClO氧化降解抗生素及消毒-清水池\"的处理系统,在九龙江流域高藻爆发期完成了工程化试验.结果表明,当砂滤出水总藻密度为2.04×103cells/mL时,注入相同氧化剂剂量0.5mg/L处理20s后,·OH将56ng/L的诺氟沙星降解至未检出,而NaClO仅降解至54ng/L.·OH在氧化降解抗生素的同时能杀灭全部藻细胞.根据HPLC-MS/MS检测到的降解中间产物分析,·OH氧化降解诺氟沙星通过进攻哌嗪环、萘啶环和氟原子破坏药效团,直至矿化为CO2和H2O.·OH消毒后不产生消毒副产物,检测的106项指标均达到国家《生活饮用水卫生标准》（GB 5749-2006）,为我国高藻饮用水中抗生素的安全处理提供技术支撑.国家重大科研仪器研制项目(NSFC:61427804);;科技部创新人才推进计划重点领域创新团队(2015RA4008);;国家自然科学基金资助重大研究计划(91441132

Research on the rapid inactivation of typical algae blooms by hydroxyl radical

以典型水华藻铜绿微囊藻、针杆藻和四尾栅藻为研究对象,利用大气压强电离放电高效生成的羟基自由基(·OH)对3种藻进行杀灭.采用荧光染色、流式细胞仪; 和光合活性等生物学方法,确定·OH杀灭的阈值浓度和时间,并观察细胞形态变化.结果表明,当混合藻中铜绿微囊藻、针杆藻和四尾栅藻的初始藻密度分别为1; 9.5*10~4、21.8*10~4和4.90*10~4cells/mL时,; ·OH杀灭的阈值浓度为1.07mg/L,致死时间为4.5s;形态观察结果表明,处理后各种藻的形态是完整的,无内溶质溢出.因此,采用·OH可实现高; 效快速杀灭水华藻,有效保障饮用水安全.Algae blooming in water sources breaks out increasingly and seriously; threatened the water supply safety. Bench scale tests were conducted to; study the effects of ·OH generated from strong ionization discharge and; high pressure water jet cavitation on cell density, cell integrity and; photosynthetic capacity of 3kinds of typical freshwater algae. Algae; species including Microcystis aeruginosa, Synedra sp., and Scenedesmus; quadricuauda were respectively prepared at concentrations of 19.5*10~4,; 21.8*10~4 and 4.90*10~4 cells/mL, and the cell integrity was assessed by; flow cytometry. Results suggested that the ·OH lethal threshold of the; algae was 1.07mg/L within the exposure time of 4.5s. The cell; morphological observation results showed that all the cells were; integral and no cytoplasm composition spilled. Hence, large-scale; production of ·OH is a novel method to inactive typical algae species; efficiently and to protect drinking water safety simultaneously.国家科技支撑计划资助项目; 国家重大科研仪器研制项

Treatment of algae bloom water using ·OH based on conventional drinking water process

我国水体的富营养化日益严重,水源地出现季节性藻类爆发现象,严重威胁饮用水安全。以厦门市莲坂水厂各工艺段出水为研究对象,采用大气压强电离放电产生羟; 基自由基(·OH),分别对水源水、混凝沉淀出水、砂滤出水进行处理,处理时间为4.5 s。当注入总氧化剂浓度为1.8 mg·; L~(-1)时,高藻浓度从25.3*10~4 cells · mL~(-1)降到800 cells ·; mL~(-1);对混凝沉淀出水注入总氧化剂0.6 mg· L~(-1)、砂滤出水注入0.2 mg·; L~(-1)时,藻细胞都未检出;·OH处理后CODMn、TOC及UV254均有明显降低,砂滤出水三卤甲烷小于8; mug·L~(-1);检测的各项指标均达到国家《生活饮用水卫生标准》(GB; 5479-2006)。因此,·OH可快速有效安全地杀灭高藻,为我国高藻水源地饮用水卫生安全保障提供技术支撑。Due to the increasing eutrophication in China, harmful algae blooms; often occur in water body periodically, which poses serious threats to; drinking water safety. Using a strong ionization discharge technology at; atmosphere pressure, ·OH was used to remove algae bloom. Other; conventional process such as coagulation, sedimentation and sand; filtration were applied respectively in the Lianban Water Plant in; Xiamen (China). The total reaction time required in the three water; processes was only 4.5 s. When the total reactive oxidant (TRO); concentration injected to algae bloom water was 1.8 mg·L~(-1), the algae; content was decreased by ·OH from 25.3*10~4 cells·mL~(-1) to 800; cells·mL~(-1). When the TRO that was injected into coagulation,; sedimentation and sand filtration water achieved 0.6 mg·L~(-1) and 0.2; mg·L~(-1), respectively, the algae contents were not detected (ND) in; treated effluents. At the same time, water quality in CODMn, TOC and; UV254 were decreased and the disinfection by-products(DBPs) such as,; trihalomethanes (THMs) concentration was lower than 8 mug·L~(-1) in; treated effluents. The treated effluent, resulting from this technology,; met the requirement of the National Drinking Water Standards (GB; 5479-2006). Therefore, ·OH was effective and safe to remove freshwater; algae without further treatment being required.国家科技支撑计划项目; 国家重大科研仪器研制项目; 科技部创新人才推进计划重点领域创新团

Generating High-concentration Solution of Reactive Oxygen Species by Strong-field Ionization Discharge

为优化氧活性粒子(rOS)在水中的生成条件,并为rOS溶液生成装置提供优化系统参数的依据,研究了rOS质量浓度在水温、PH值、O2给气体积流量、rOS投加体积质量,以及系统气压(混溶压力)等因素作用下的变化规律。实验中,气态rOS在强电离条件下通过介质阻挡放电生成,以O3计,通过O3检测仪测定其浓度;水中rOS质量浓度采用dPd分光光度法测定,用CrS来表示。实验结果表明:水温、PH值与CrS呈极显著负相关(相关系数P0.05);CrS在水温分别为16℃与24.5℃之间、PH=6.5与PH=7.0之间、O2给气体积流量为2 l/MIn与3 l/MIn之间均为差异不显著(P>0.05),其余各水温、PH值、O2给气体积流量之间均为差异显著(PO2给气体积流量>系统气压与O2给气体积流量交互作用。To optimize the generating condition of reactive oxygen species(ROS) in solution, and to provide a reference for improving ROS preparation system, we investigated the effects of several parameters, including solution temperature, solution pH, O2 input, ROS dosages, and system pressure, on the concentration of obtained ROS solution.Gaseous ROS was generated in a strong-field ionization condition induced by under dielectric barrier discharge(DBD), and its dosage represented by O3 was measured by ozone monitor.ROS in solution was caught by DPD(N, N-diethyl-p-pHenylenediamine), which was measured by DPD spectrophotometry, and the concentration of ROS solution was denoted by CRS.According to the experiments, both water temperature and pH have significant negative correlation with CRS(relativefactor P0.05).The differences between CRS are insignificant(P>0.05) under conditions of solution temperature of 16 ℃, 20 ℃, 24.5 ℃, solution pH of 6.5 and 7.0, as well as O2 input of 2 L/min and 3 L/min(P>0.05), but they are highly significant(P<0.01) or significant(P<0.05) under other tested conditions.Moreover, CRS significantly increases with the decrease of miscibility pressure(P<0.01), and it is significantly affected by the interaction between miscibility pressure and O2 input under higher ROS dosages(P<0.01).Lower water temperature, lower pH, higher ROS dosages, and lower miscibility pressure are all beneficial to increasing the concentration of ROS(CRS), which is significantly affected by the change of several parameters including solution temperature in the lower range, pH around 7, O2 input in the range of larger amount, etc.On the condition of high ROS dosage input, CRS is influenced by miscibility pressure, O2 input, and the interaction between miscibility pressure and O2 input in a descending order.国家高技术研究发展计划(863计划)(2012AA062609); 国家科技支撑计划(2013BAC06B02); 国家杰出青年科学基金(61025001)~

Electric-field-induced selective catalysis of single-molecule reaction

随着单分子电学检测技术的迅速发展，分子电子学的研究不再局限于分子电子学器件的构筑及其电学性质的测量，而且扩展到单分子尺度化学反应过程的探索。然而目前相关的研究仍然局限于理论计算方面，在单分子尺度上实时监测和调控化学反应的活性和选择性是化学领域的长期目标和挑战。针对这一挑战，洪文晶教授课题组与程俊教授课题组合作，自主研发了精密科学仪器，将单个有机分子定向连接在两个末端尺寸为原子级的电极之间，解决了化学反应中分子取向控制的问题.理论计算结果证实了定向电场可以有效地稳定化学反应的过渡态，从而降低反应能垒。该研究工作在化学化工学院洪文晶教授、程俊教授、能源材料化学协同创新中心（iChEM）刘俊扬副研究员的共同指导下完成，由硕士研究生黄晓艳、iChEM博士研究生唐淳、博士研究生李洁琼以及兰州大学的陈力川博士作为共同第一作者，化学化工学院师佳副教授、陈招斌高级工程师、夏海平教授和田中群教授，萨本栋微纳研究院杨扬副教授、环境与生态学院白敏冬教授以及兰州大学张浩力教授参与了研究工作的讨论并给予指导，博士后乐家波、博士研究生郑珏婷、张佩（已毕业）、李瑞豪、李晓慧也参与了研究工作。Oriented external electric fields (OEEFs) offer a unique chance to tune catalytic selectivity by orienting the alignment of the electric field along the axis of the activated bond for a specific chemical reaction; however, they remain a key experimental challenge. Here, we experimentally and theoretically investigated the OEEF-induced selective catalysis in a two-step cascade reaction of the Diels-Alder addition followed by an aromatization process. Characterized by the mechanically controllable break junction (MCBJ) technique in the nanogap and confirmed by nuclear magnetic resonance (NMR) in bottles, OEEFs are found to selectively catalyze the aromatization reaction by one order of magnitude owing to the alignment of the electric field on the reaction axis. Meanwhile, the Diels-Alder reaction remained unchanged since its reaction axis is orthogonal to the electric fields. This orientation-selective catalytic effect of OEEFs reveals that chemical reactions can be selectively manipulated through the elegant alignment between the electric fields and the reaction axis.This work was supported by the National Key R&D Program of China (2017YFA0204902), the National Natural Science Foundation of China (21722305, 21703188, 21673195, 21621091, 51733004, 51525303, and 91745103), the China Postdoctoral Science Foundation (2017M622060), and the Young Thousand Talents Project of China. 该工作得到国家自然科学基金委（21722305、21703188、21673195、51733004、51525303、91745103），国家重点研发计划课题（2017YFA0204902），中国博士后面上基金（2017M622060）的资助，以及固体表面物理化学国家重点实验室、醇醚酯化工清洁生产国家工程实验室、能源材料化学协同创新中心的支持

Production of hydrogen and acetone-butanol from steam-exploded straw by Clostridium fermentation

氢气和丁醇是清洁高效的新能源，发酵法制取氢气和丁醇是近年来的研究热点。现有的研究主要是利用有机废弃物或玉米淀粉的液态发酵，存在成本高，污染严重等问题。本文以可再生的农作物秸秆为原料，研究新型发酵方式，为实现高效的氢气和丁醇发酵探索新途径。多数梭菌都能利用葡萄糖、木糖和纤维二糖等糖类，因而可以利用秸秆中的纤维素和半纤维素为碳源进行发酵。其中，丁酸梭菌（Clostridium butyricum）和丙酮丁醇梭菌（Clostridium acetobutylicum）是两种典型的具有相似代谢途径的厌氧梭菌，都能够发酵生产氢气，后者还可生产丙酮和丁醇。本文首先对秸秆进行汽爆预处理，探索了C. butyricum AS1.209和 C. acetobutylicum AS1.132利用汽爆秸秆生产氢气和丙酮丁醇的新型发酵方式，并对汽爆预处理及不同发酵方式引起的微生物代谢的变化进行了探索。汽爆预处理是提高木质纤维素原料发酵效率的有效途径。研究了汽爆预处理条件对汽爆秸秆发酵效果的影响，结果表明，在饱和水蒸气压力1.5MPa，维压时间8min条件下处理的汽爆秸秆最适于梭菌发酵。与未处理秸秆相比，C. butyricum AS1.209利用汽爆秸秆发酵的最大产氢量为65ml/g-SES，是未处理秸秆的13倍。在相同条件下，C. butyricum AS1.209的产氢量C. acetobutylicum AS1.132的1.5倍。同步糖化发酵是常用的木质纤维素有效利用方式之一，本研究将其用以汽爆秸秆产氢过程，并加以改进。以C. butyricum AS1.209为产氢菌，考察了恒温同步糖化发酵，周期变温同步糖化发酵和两相法同步糖化发酵三种发酵方式。结果表明，虽然恒温同步糖化发酵方式可以达到较好的发酵效果，但存在着纤维素酶解的最适温度和微生物发酵的最适温度不一致的问题。提出了周期变温同步糖化发酵和两相法同步糖化发酵两种方式以解决这一矛盾，产氢量分别比恒温同步糖化发酵提高了12%和10%。纤维素酶成本高是木质纤维素原料发酵的关键限制性因素之一。本文设计了纤维素酶和氢气顺次发酵的工艺，以降低纤维素酶成本。与直接加酶制剂的发酵相比，顺次发酵产氢的延迟期缩短了90%以上，发酵周期缩短30%以上。经补料后，产氢量和最大比产氢率分别提高10%和25%，纤维素和半纤维素的利用率分别提高10%和12%。通过对同步糖化发酵和顺次发酵的可溶性代谢产物进行分析，发现了汽爆预处理和纤维素酶发酵对丁酸梭菌代谢的影响。采用同步糖化发酵方式，利用未处理秸秆发酵的丁酸产量占总可溶性代谢产物41%，是乙酸产量的1.3倍。而利用汽爆秸秆发酵时，乙酸的产量占44%，是丁酸产量的1.4倍。说明汽爆预处理不但使秸秆的结构和组成发生显著变化，而且对微生物代谢途径也产生了显著影响。但是，在利用汽爆秸秆进行顺次发酵的可溶性代谢产物中，丁酸产量占48%，是乙酸产量的2.3倍。说明在经过纤维素酶发酵后，底物组成和结构的变化进一步影响了丁酸梭菌的代谢途径。丙酮丁醇梭菌是发酵生产丁醇的优良菌株，同时也能产生丙酮、乙醇和氢气。本文探索了汽爆秸秆分步水解发酵和膜循环酶解耦合发酵两种方式对丙酮丁醇发酵的影响。结果表明，利用pH4.8的稀硫酸酶解汽爆秸秆，并使用Ca(OH)2中和酶解液后，分步水解发酵的效果最佳。膜循环酶解耦合发酵使新鲜酶解液不断进入发酵罐，不但避免了溶剂浓度过高对菌体造成的毒性，还解除了纤维素酶解产糖对酶的反馈抑制。纤维素酶能够循环利用，节约了酶用量，消耗单位滤纸酶活所产生的丁醇量为0.0039 g/IU，是分步水解发酵的1.5倍

生物质转化的共性问题研究——生物质科学与工程学的建立与发展

生物质资源的高值转化是研究热点。由于现有的生物质利用技术存在的技术单一,缺乏系统性理论指导等问题,导致原料利用率低,经济效益差,难以实现工业化生产,迫切需要建立新的理论体系。通过深入分析生物质转化过程中的共性问题,在综合多学科知识的基础上,提出了生物质科学与工程学这一理念,从生物质原料工程学,生物质转化过程工程学和生物质产品工程学三方面对生物质利用技术进行了全面、系统的研究,为生物质类可再生资源的高值化利用提供了新的研究思路

变温调控对汽爆秸秆发酵产氢的影响

在以汽爆秸秆为原料,利用丁酸梭菌(Clostridium butyricum)同步糖化发酵产氢的过程中,存在着纤维素酶解和微生物发酵的最适温度不一致的矛盾,影响底物的转化和微生物利用。在发酵开始10 h和30 h的时候,分别进行两次变温调控,首先迅速升温至45℃,保持2 h后又迅速将温度降低回到丁酸梭菌的最适发酵温度35℃。这一变温调控能够促进纤维素酶解,并有利于微生物保持高活性。与恒温发酵相比,两次变温的最终产氢量提高1.2倍,纤维素和半纤维素的转化率分别为75%和88%

汽爆秸秆膜循环酶解耦合丙酮丁醇发酵

利用新型的汽爆玉米秸秆膜循环酶解耦合发酵系统进行了丙酮丁醇发酵的研究,并对使用该系统所导致的丙酮丁醇梭菌(Clostridium acetobutylicum AS1.132)代谢的变化进行了讨论.在稀释率为0.075h-1的条件下,丁醇的产量为0.14g/g(纤维素+半纤维素),最大丁醇产率达到0.31g/(L-h),溶剂组成为丁醇:丙酮:乙醇65.3:24.3:10.4(体积比),纤维素和半纤维素的转化率分别为72%和80%,使用单位纤维素酶所产生的丁醇量为3.9mg/IU,是分步水解批次发酵的1.5倍.利用该系统使酶解和发酵分别在各自最适的条件下同时连续进行,减少了纤维素酶的用量,有效地解除了酶解产物对纤维素酶的抑制作用,并减轻了溶剂产物尤其是丁醇对微生物活性的影响,延长了发酵周期