Pharmaceuticals, personal care products and endocrine-disrupting chemicals in U.S. surface and finished drinking waters: A proposed ranking system

This study developed a comprehensive ranking system, for the first time as per authors' knowledge, for prioritizing the monitoring of pharmaceuticals and personal care products and endocrine-disrupting chemicals (together termed as EOCs, hereafter; a total of 100 EOCs considered) in U.S. stream water/source water and finished drinking water (termed as “EOCRank,” hereafter). The EOCRank system was developed using a total of 4 criteria: (1) occurrence, (2) treatment in drinking water treatment plants, (3) ecological effects, and (4) health effects and characterized using 7 attributes: prevalence, frequency of detection, removal, bioaccumulation, ecotoxicity (for fish, daphnid, and algae aquatic indicator species), pregnancy effects, and health effects. The health effects attribute was characterized using 7 sub-attributes: carcinogenicity, mutagenicity, impairment of fertility, central nervous system acting, endocrine effects, immunotoxicity, and developmental effects. Rank scores of EOCs were calculated as summations of multiplications of importance weights and utility functions of multiple criteria and were arranged to highlight EOCs needing immediate attention. Two different ranking lists of EOCs were developed for U.S. finished drinking water and stream water/source water and observed to differ with each other, indicating the effect of water type on ranking of EOCs. A ranking list of priority EOCs, developed using a particular criterion, was observed to differ with that, developed using multiple criteria. Health effects and treatment criteria were observed to be important criteria influencing overall data gap rank scores and need further data collection. The generalized nature of the system could be customized for specific geographical locations (occurrence information and importance weights of different components). The developed database of the EOCRank system is available on: http://www.egr.msu.edu/~xagorara/research.html).     

环烯烃共聚物芯片在电泳分析检测中的应用

微芯片电泳是一种快速高效的微分析技术,有巨大的应用潜力,但由于芯片制作成本高、方法的实用性不足,目前在实际样品分析中的应用仍然相当有限。为了促进微芯片电泳的实际应用,本研究利用廉价的环烯烃共聚物（COC）塑料芯片,结合实验室自己搭建的低成本程控高压电源和激光诱导荧光检测装置（LIF）,对DNA片段、氨基酸、苏丹红类染料进行分析检测,得到了较好的分离效果。     

Copolymerization of norbornene with ethylene: A high-resolution liquid NMR, DSC and solid state NMR study

In this paper, we report the monomer reactivity on the copolymerization of norbornene and ethylene. The reactivity ratios for ethylene (M₁) and norbornene (M₂) are 18.5 and 0.035, respectively. Different copolymerization conditions can produce COC with different microstructures. A ¹³C NMR shift assignment in pentad sequences in copolymers has been obtained. More isolated polynorbornene or a micro-block length can be obtained using a low Zr/Al catalyst/co-catalyst ratio and at a lower NB/ethylene feed ratio. The T_1p ^C decay curve shows two component decays in all resonance peaks. These two component decays come from different norbornene microstructures, while the block and alternative have similar T_1p ^C values.     

Physical Aging of Cyclo Olefin Copolymer (COC)

The physical aging behaviour of the cyclo olefin copolymer (COC) has been investigated in this paper by using low temperature annealing in differential scanning calorimeter (DSC) measurements. The data of recovered enthalpies was fitted by means of Petrie–Marshall (PM), Cowie–Ferguson (CF) or Kohlrausch–Williams–Watts (KWW) form equation in describing the enthalpy relaxation. We have found that the COC sample has a stretched exponential factor near 1.0 (=0.98±0.02) at the annealing temperature range.The apparent activation energy (E _H) of COC aging obtained by using the Petrie/Marshall (PM) analysis method is about 1521.7±150 kJ/mole. That is substantially higher than 308±50 kJ/mole for bisphenol-A polycarbonate, 407.4 kJ/mole for poly (vinyl methyl ether) and 1192 kJ/mole for polystyrene, but close to 1520 kJ/mole for polyterafluoroethylene (PTFE).     

Development of an advanced human–machine interface for next generation nuclear power plants

An advanced human–machine interface (HMI) has been developed to enhance the safety and availability of a nuclear power plant (NPP) by improving operational reliability. The key elements of the proposed HMI are the large display panels which present synopsis of plant status and the compact, computer-based work stations for monitoring, control and protection functions. The work station consists of four consoles such as a dynamic alarm console (DAC), a system information console (SIC), a computerized operating-procedure console (COC), and a safety system information console (SSIC). The DAC provides clean alarm pictures, in which information overlapping is excluded and alarm impacts are discriminated, for quick situation awareness. The SIC supports a normal operation by offering all necessary system information and control functions over non-safety systems. In addition, it is closely linked to the other consoles in order to automatically display related system information according to situations of the DAC and the COC. The COC aids operators with proper operating procedures during normal plant startup and shutdown or after a plant trip, and it also reduces their physical/mental burden through soft automation. The SSIC continuously displays safety system status and enables operators to control safety systems. The proposed HMI has been evaluated using the checklists that are extracted from various human factors guidelines. From the evaluation results, it can be concluded that the HMI is so designed as to address the human factors issues reasonably. After sufficient validation, the concept and the design features of the proposed HMI will be reflected in the design of the main control room of the Korean Next Generation Reactor (KNGR).     

利用条件生成对抗网络的光场图像重聚焦

目的 传统的基于子视点叠加的重聚焦算法混叠现象严重,基于光场图像重构的重聚焦方法计算量太大,性能提升困难。为此,本文借助深度神经网络设计和实现了一种基于条件生成对抗网络的新颖高效的端到端光场图像重聚焦算法。方法 首先以光场图像为输入计算视差图,并从视差图中计算出所需的弥散圆(circle of confusion,COC)图像,然后根据COC图像对光场中心子视点图像进行散焦渲染,最终生成对焦平面和景深与COC图像相对应的重聚焦图像。结果 所提算法在提出的仿真数据集和真实数据集上与相关算法进行评价比较,证明了所提算法能够生成高质量的重聚焦图像。使用峰值信噪比(peak signal to noise ratio,PSNR)和结构相似性(structural similarity,SSIM)进行定量分析的结果显示,本文算法比传统重聚焦算法平均PSNR提升了1.82 d B,平均SSIM提升了0.02,比同样使用COC图像并借助各向异性滤波的算法平均PSNR提升了7.92 d B,平均SSIM提升了0.08。结论 本文算法能够依据图像重聚焦和景深控制要求,生成输入光场图像的视差图,进而生成对...     

Melt-reprocessable linear low-density polyethylene/cyclic olefin copolymer blends with low dielectric constant and low thermal expansion

Insulation materials with low dielectric constants, low coefficients of thermal expansion (CTE), low densities, renewability, and low cost are urgently needed in the fields of communication, control and signal cables. Here we report that combining cyclic olefin copolymer (COC) with linear low-density polyethylene (LLDPE) by melt blending achieves the above goals. The dielectric constant and CTE of LLDPE/COC blends are minimized at 20 wt% COC content, reaching a value of 2.23 at 1000 Hz and 1.21 × 10⁻⁴ K⁻¹, respectively. The density of the blend increases by only 1.6% compared with LLDPE, whereas the tensile modulus increases by 56%, which is conducive to the blends to improve mechanical strength while preserving lightweight. The rheological tests show that the zero-shear viscosity, storage modulus, and loss modulus of the LLDPE/COC blends do not change much compared with pristine LLDPE, maintaining their good melt processability at 160°C. The cyclic rigid structure of COC causes a decrease in CTE, and the increase in free volume between molecular chains is responsible for the reduced dielectric constant. The present work provides a promising route to the design and fabrication of melt-reprocessable polymer composites with low dielectric constant and low thermal expansion.     

Large-strain thermo-mechanical behavior of cyclic olefin copolymers: Application to hot embossing and thermal bonding for the fabrication of microfluidic devices

Amorphous cyclic olefin copolymers (COCs) are beginning to be used for making microfluidic devices for life science applications. Typically, both micro-scale and nano-scale channels are imprinted onto the copolymer by hot embossing. However, optimal manufacturing process conditions will only be possible if the COCs thermo-mechanical behavior is experimentally well characterized, mathematically modeled, and implemented in a numerical simulation. We have conducted large-strain compression experiments on two commercial grades of COCs: TOPAS-8007, and TOPAS-6015 in a wide temperature, and strain rate range. A constitutive theory and numerical implementation developed by Srivastava et al. [1] was applied to model the behavior of TOPAS. We have employed that numerical implementation, together with the material parameters for TOPAS determined here, to predict the response of TOPAS in the following microfluidic fabrication operations: (i) micro-scale hot embossing on TOPAS-8007 to replicate a micro-chip; and (ii) for sealing the channels in the micro-chip: (a) thermal bonding of an embossed chip of TOPAS-8007 with a cover plate of TOPAS-8007; and (b) thermal bonding of an embossed chip of TOPAS-6015 with a cover plate of TOPAS-8007. We show that the model can provide a simulation capability for estimation of the processing parameters for hot embossing and thermal bonding.     

Improvement of thermal bond strength and surface properties of Cyclic Olefin Copolymer (COC) based microfluidic device using the photo-grafting technique

This paper reports on the development and application of a permanent surface modification technique (photo-grafting) as an improved method for bonding COC (TOPAS) microfluidic substrates with a cover plate without affecting the channel integrity. This technique not only helps to increase the bond strength of the original device but also makes the surface hydrophilic which is essential for quick fluid flow while passing analytes through the device. The bond strength of the modified and unmodified chips was measured using the tensile and peel tests. It was observed that the bond strength of the modified chips has increased approximately 6 times to 1.18 (±0.08) MPa compared to 0.21 (±0.05) MPa for the unmodified chip. The modified surface was evaluated using X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and water contact angle measurement. The contact angle of the modified surface decreased to 20 ± 5° from 85 ± 3° for the untreated substrate. Scanning electron microscope and confocal microscope examinations of cross-sectional profiles of the bonded chips indicated that the integrity of the channel features was successfully preserved.     

茂金属聚烯烃的特性和应用

从90年代初以来应用茂类金属化合物催化剂体系合成聚烯烃的技术在很多公司进入工业化生产阶段,随之其加工性能研究和产品开发工作也进展很快.茂金属聚合物的特性引起人们的广泛关注,关于茂金属聚合物的信息和报道越来越多.本文选取了从1992年～1997年间的部分文献,综合介绍了茂金属聚合物(sPP、m-LLDPE、PS、和COC等)的物理性能、加工特性和产品应用的基本情况.