Investigation and improvement of reversible microfluidic devices based on glass–PDMS–glass sandwich configuration

Reversibly assembled microfluidic devices are dismountable and reusable, which is useful for a number of applications such as micro- and nano-device fabrication, surface functionalization, complex cell patterning, and other biological analysis by means of spatial–temporal pattern. However, reversible microfluidic devices fabricated with current standard procedures can only be used for low-pressure applications. Assembling technology based on glass–PDMS–glass sandwich configuration provides an alternative sealing method for reversible microfluidic devices, which can drastically increase the sealing strength of reversibly adhered devices. The improvement mechanism of sealing properties of microfluidic devices based on the sandwich technique has not been fully characterized, hindering further improvement and broad use of this technique. Here, we characterize, for the first time, the effect of various parameters on the sealing strength of reversible PDMS/glass hybrid microfluidic devices, including contact area, PDMS thickness, assembling mode, and external force. To further improve the reversible sealing of glass–PDMS–glass microfluidic devices, we propose a new scheme which exploits mechanical clamping elements to reinforce the sealing strength of glass–PDMS–glass sandwich structures. Using our scheme, the glass–PDMS–glass microchips can survive a pressure up to 400 kPa, which is comparable to the irreversibly bonded PDMS microdevices. We believe that this bonding method may find use in lab-on-a-chip devices, particularly in active high-pressure-driven microfluidic devices.     

构树皮丙酮抽出物的DEAE—Sephadex分离及GC—MS分析

利用ＤＥＡＥ—Ｓｅｐｈａｄｅｘ分离柱及ＧＣ—ＭＳ对构树皮丙酮抽出物 进行了分离和分析．在丙酮抽出物中中性组分占抽出物的５９．７％，弱酸性 组分和强酸性组分分别占２５．９％和１０．３％．中性组分中不皂化物占 ８９．２％，皂化物仅占８．４％．不皂化物的成分比较复杂，所检出的主要有 甾醇和甾酮类．皂化物中亚油酸占５０％，软脂酸占２１％．弱酸性组分中 ５０％以上是脂肪酸（亚油酸和软脂酸），而没有松香酸．     

MLS4531立式辊磨的开发与研制

在研究国内外立式辊磨的基础上开发出MLS4531立式辊磨,结合工程实际优化了技术参数、研磨机构及其附属装置。在调试中对MLS4531立式辊磨的液压系统,安全装置进行了改进。     

宽带直流放大器的增益控制设计与研究

首先进行了方案论证与比较,分析各种方案的优点缺点,最后选择亚德诺半导体公司生产的低噪声增益可控集成运算放大器AD603和电流反馈型宽带运算放大器AD811等器件设计宽带直流放大器。输入级采用两级AD603级联,输出级设计通频带0~10MHz的带宽,通过单片机可以对放大器增益进行控制。该放大器具有频带宽、功率高、增益可调、带宽可选择等特点。此外,对提高直流放大器的各种性能指标提出了多种具体措施,在要求较高的系统中具有较强的实用性。     

陶瓷注射成形技术进展

陶瓷粉末注射成形是从现代粉末注射成形技术中发展起来的一项新型成形技术。本文着重论述了陶瓷注射成形发展的历史、技术特点、工艺及进展情况，并介绍了CIM的典型产品和应用领域。     

耐磨、透明有机硅涂层研究动向

本文叙述了制备透明、耐磨有机硅树脂的方法；水解催化剂、烷氧基硅烷组成、添加二氧化硅、溶剂成分、促粘和固化催化剂的研究进展     

Identification and fermentation optimization of protopectinase-overproducing strain Aspergillus niger CD-01 for pectin production

In order to solve the citrus peel resource waste problem and minimize the drawbacks of chemical extraction of pectin, a protopectinase-overproducing strain CD-01 for pectin production was isolated from a pit soil dumped with perished orange in Changde City, Hunan Province of China. The strain CD-01 had the same morphology and 28S rRNA gene sequence (FJ184995) as that of Aspergillus niger (ATCC 64028). It was thus identified and named as Aspergillus niger CD-01. The fermentation condition was optimized based on L₉(3⁴) orthogonal experimental design and the variances analyses. The results show that the optimal condition for producing pectin is as follows: time 36 h, temperature 35 °C, pH 5, and urea as the nitrogen source. Under this condition, the pectin yield can reach up to 24.5%. This shows a great potential of Aspergillus niger CD-01 in pectin extraction from citrus. Foundation item: Projects(50621063, 50674101) supported by the National Natural Science Foundation of China     

假颗粒现象及其对再生铝镁碳制品性能的影响

对用后铝镁碳砖再生颗粒料的组成和结构特点进行显微分析,并通过改变混料方式以及不同粒度再生料的加入量研究假颗粒对再生铝镁碳制品结构与性能的影响。结果表明：用后铝镁碳砖再生料中含有约40%与废砖相组成和结构相似、骨料与基质并存于同一颗粒的二次颗粒,即所谓的＂假颗粒＂,假颗粒的组成、结构及外形的均匀程度均远不如一次骨料颗粒;混碾可使用后铝镁碳砖再生料中假颗粒发生二次破碎,且粒度越大,发生二次破碎的颗粒数量越多;假颗粒二次破碎导致再生制品的粒度组成发生改变,进而影响其密度和耐压强度。     

Supervised discrete hashing through similarity learning

Multimedia Tools and Applications - Supervised hashing has achieved better accuracy than unsupervised hashing in many practical applications owing to its use of semantic label information. However,...     

Person re-identification based on multi-appearance model

Person re-identification plays important roles in many practical applications. Due to various human poses, complex backgrounds and similarity of person clothes, person re-identification is still a challenging task. In this paper, we mainly focus on the robust and discriminative appearance feature representation and proposed a novel multi-appearance method for person re-identification. First, we proposed a deep feature fusion method and get the multi-appearance feature by combining two Convolutional Neural Networks. Then, in order to further enhance the representation of the appearance feature, the multi-part model was constructed by combining the whole body and the six body parts. Additionally, we optimized the feature extraction process by adding a pooling layer. Comprehensive and comparative experiments with the state-of-the-art methods over publicly available datasets demonstrated that the proposed method can get promising results.