细胞固定化催化生产精细化学品的研究进展Q

摘要：细胞固定化技术具有流程简单、生物相容、操作稳定等优点，可有效保证细胞活性，实现高效的细胞催化生产精细化学品。本文介绍了表面附着、凝胶包埋、聚电解质层层自组装膜等多细胞固定化方法，及其在二元醇、生物乙醇、乳酸、酯、多糖等精细化学品生产中的研究现状和进展，并分析讨论了各种方法存在的问题。同时，总结了近年来新发展的单细胞纳米涂层固定化方法的机理、趋势及应用于精细化学品生产的可能性。最后对细胞固定化催化生产精细化学品面临的技术挑战及研究方向做出展望，以期为精细化学品生产提供一定的技术支持。     

垂直筛板塔流体力学与传质研究状况

对我国在新型垂直筛板塔的流体力学性能 ,诸如塔板干板压降与湿板压降、板孔漏液、塔板过量雾沫夹带、板上帽罩单元的液体提升能力与液体循环程度的研究及其传质性能 ,诸如塔板传质效率模型、塔板空间气相中液体大小与分布、板间空间立体传质作用的研究等进行了综合 ,并予以分析论述 ,从中看出我国对新型垂直筛板塔已进行了较全面深入的研究工作 ,并取得了新进展。     

等离子硅刻蚀及其工艺参数的多尺度优化

用CFD-ACE+和CFD-TOPO分别对容性耦合等离子体反应腔室放电和等离子硅刻蚀过程进行仿真,讨论不同射频电压和腔室条件对等离子体特性的影响.结果表明:随着射频电压的升高,离子的通量增大;在低射频电压时,离子通量随腔室压强的升高而减小,而在高射频电压时趋势则相反.用Kriging模型对影响刻蚀形貌的参数(腔室压强和射频电压)进行优化,结果表明该优化方法可以为工艺条件相近的刻蚀机设备的设计提供参考.     

模数对无机富锌涂料和涂层性能的影响

硅酸钾富锌涂料是目前广泛使用的钢铁防腐蚀涂料。作为涂料粘结剂的高模数硅酸钾溶液对涂料和涂层的性能有重要影响。本研究考察了硅酸钾粘结剂的模数变化对涂料及涂层性能产生的影响。实验结果表明：粘结剂模数的提高可以提高固化后涂层的耐水性能，当粘结剂模数在5.0左右时，所得富锌涂层具有最佳的耐磨性能，但当粘结剂模数超过5.5时会造成涂料施工性能和贮存稳定性下降，涂层柔韧性降低，从而降低涂层的耐磨性能。     

Synthesis and characterization of a new water-soluble endohedral metallofullerene for MRI contrast agents

Water-soluble amino acid derivatives of gadolinium (Gd) endohedral metallofullerenes (AAD-EMFs), Gd@C₈₂O_m(OH)_n(NHCH₂CH₂COOH)_l (m ≈ 6, n ≈ 16 and l ≈ 8) are synthesized by a direct reaction of the pure endohedral metallofullerene Gd@C₈₂ with an excess of alkaline solution of β-alanine. The structure of the AAD-EMFs is characterized by FTIR, XPS and laser-desorption time-of-flight (LD-TOF) mass spectrometries. Water proton relaxivity analysis indicates that the longitudinal relaxivity R₁ (the effect on 1/T₁, 9.1 mM⁻¹ s⁻¹) of AAD-EMFs is higher than that of the commercial MRI contrast agent, Magnevist (gadolinium-diethylenetriaminepentaacetic acid, Gd-DTPA, 5.6 mM⁻¹ s⁻¹). The MRI phantom studies are performed to confirm the high efficiency of this sample as MRI contrast agents.     

Morphologic study of electrochemically formed lead dioxide

Various electrochemical methods with different conditions were used to prepare lead dioxide (PbO₂). The observation revealed that the morphology of deposited PbO₂ could be controlled by simply changing deposition parameters. Under the condition of oxygen evolution, which dominates the electrode process, uniformly distributed high porous structured PbO₂ was formed. The results indicated that large current density or high potential polarization should be one of the most important and necessary factors for forming high surface area PbO₂ deposit. Only β-PbO₂ was identified by X-ray diffraction measurement for the deposit prepared by present methods and solution. One potential application of this method is to prepare nanoscaled PbO₂ parallel lines.     

油田废水电解杀菌研究

采用电解杀菌技术处理油田废水，研究了电解时间、电流强度、极板间距以及电极联结方式等因素对废水中硫酸盐还原菌杀灭效果的影响。结果表明，油田废水经3min电解杀菌，硫酸盐还原菌杀灭率高达99．90％。随着电解时间的增加，硫酸盐还原菌的杀菌率进一步提高；电流强度增加，硫酸盐还原菌的杀灭率升高。在电流强度保持不变的情况下，随着极板间距增加，极板之间电压升高，更有利于杀灭硫酸盐还原菌。在极板间电流强度相同的条件下，两种电极联结方式的杀菌率差别不大，杀菌率均在99．9％以上。     

微生物降解原油发酵液中低分子量有机酸的测定

本文使用气-质联用仪对微生物降解原油发酵液中低分子量有机酸进行测定。采用水蒸汽蒸发法蒸出发酵液中低分子量有机酸，从而使其与样品中大量的无机盐和表面活性剂分离，浓缩后直接进样。该方法简单直接，可以减少有机酸的损失。     

Coupling-and-decoupling: A hierarchical model for occlusion-free object detection

Handling occlusion is a very challenging problem in object detection. This paper presents a method of learning a hierarchical model for X-to-X occlusion-free object detection (e.g., car-to-car and person-to-person occlusions in our experiments). The proposed method is motivated by an intuitive coupling-and-decoupling strategy. In the learning stage, the pair of occluding X?s (e.g., car pairs or person pairs) is represented directly and jointly by a hierarchical And–Or directed acyclic graph (AOG) which accounts for the statistically significant co-occurrence (i.e., coupling). The structure and the parameters of the AOG are learned using the latent structural SVM (LSSVM) framework. In detection, a dynamic programming (DP) algorithm is utilized to find the best parse trees for all sliding windows with detection scores being greater than the learned threshold. Then, the two single X?s are decoupled from the declared detections of X-to-X occluding pairs together with some non-maximum suppression (NMS) post-processing. In experiments, our method is tested on both a roadside-car dataset collected by ourselves (which will be released with this paper) and two public person datasets, the MPII-2Person dataset and the TUD-Crossing dataset. Our method is compared with state-of-the-art deformable part-based methods, and obtains comparable or better detection performance.     

Efficient object detection based on selective attention

In this paper, we make use of biologically inspired selective attention to improve the efficiency and performance of object detection under clutter. At first, we propose a novel bottom-up attention model. We argue that heuristic feature selection based on bottom-up attention can stably select out invariant and discriminative features. With these selected features, performance of object detection can be improved apparently and stably. Then we propose a novel concept of saccade map based on bottom-up attention to simulate the saccade (eye movements) in vision. Sliding within saccade map to detect object can significantly reduce computational complexity and apparently improve performance because of the effective filtering for distracting information. With these ideas, we present a general framework for object detection through integrating bottom-up attention. Through evaluating on UIUC cars and Weizmann–Shotton horses we show state-of-the-art performance of our object detection model.