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Significantly improving enzymatic saccharification of high crystallinity index's corn stover by combining ionic liquid [Bmim]Cl-HCl-water media with dilute NaOH pretreatment

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BIORESOURCE technology 2015年 189卷 421-425页

作者： He, Yu-Cai Liu, Feng Gong, Lei Zhu, Zheng-Zhong Ding, Yun Wang, Cheng Xue, Yu-Feng Rui, Huan Tao, Zhi-Cheng Zhang, Dan-Ping Ma, Cui-Luan Changzhou Univ Coll Pharmaceut Engn & Life Sci Jiangsu Key Lab Adv Catalyt Mat & Technol Changzhou Peoples R China

In this study, a pretreatment by combining acidified aqueous ionic liquid 1-butyl-3-methylimidazolium chloride (IL [Bmim]Cl) solution with dilute NaOH extraction was employed to pretreat high crystallinity index (CrI) of corn stover before its enzymatic saccharification. After NaOH extraction, [Bmim]Cl-HCl-water (78.8:1.2:20, w/w/w) media was used for further pretreatment at 130 degrees C for 30 min. After being enzymatically hydrolyzed for 48 h, corn stover pretreated could be biotransformed into reducing sugars in the yield of 95.1%. Furthermore, SEM, XRD and FTIR analyses of untreated and pretreated corn stovers were examined. It was found that the intact structure was disrupted by combination pretreatment and resulted in a porous and amorphous regenerated cellulosic material that greatly improved enzymatic hydrolysis. Finally, the recovered hydrolyzates obtained from the enzymatic hydrolysis of pretreated corn stovers could be fermented into ethanol efficiently. In conclusion, the combination pretreatment shows high potential application in future. (C) 2015 Elsevier Ltd. All rights reserved.

关键词： Corn stover 1-Butyl-3-methylimidazolium chloride Ionic liquid NaOH Combination pretreatment

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Improved biosynthesis of ethyl (S)-4-chloro-3-hydroxybutanoate by adding L-glutamine plus glycine instead of NAD⁺ in β-cyclodextrin-water system

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BIORESOURCE technology 2015年 182卷 98-102页

作者： He, Yu-Cai Zhang, Dan-Ping Tao, Zhi-Cheng Lu, Yun Ding, Yun Liu, Feng Zhu, Zheng-Zhong Rui, Huan Zheng, Gao-Wei Zhang, Xian Changzhou Univ Coll Pharmaceut Engn & Life Sci Biochem Engn Lab Changzhou Peoples R China E China Univ Sci & Technol State Key Lab Bioreactor Engn Shanghai 200237 Peoples R China Rice Univ Dept Bioengn Houston TX USA

To reduce dependence on the expensive cofactor and effectively biotransform ethyl 4-chloro-3-oxobutanoate, L-glutamine and glycine were found to enhance the content of intracellular NADH and the reductase activity. Adding the mixture of 200 mM of L-glutamine and 500 mM of glycine to the reaction media, a 1.67-fold of reductase activity was increased over the control without the addition of the two compounds. Moreover, beta-cyclodextrin (0.4 mol beta-cyclodextrin/mol ethyl 4-chloro-3-oxobutanoate) was also added into this reaction media, and the biocatalytic activity of the whole-cell biocatalyst of Escherichia coli CCZU-K14 was increased by 1.34-fold than that without beta-cyclodextrin. In this beta-cyclodextrin-water media containing L-glutamine (200 mM) plus glycine (500 mM), ethyl (S)-4-chloro-3-hydroxybutanoate (>99% ee) could be obtained from 3000 mM ethyl 4-chloro-3-oxobutanoate in the yield of 98.0% after 8 h. All the positive features demonstrate the potential applicability of the bioprocess for the large-scale production of ethyl (S)-4-chloro-3-hydroxybutanoate. (c) 2015 Elsevier Ltd. All rights reserved.

关键词： beta-Cyclodextrin Ethyl (S)-4-chloro-3-hydroxybutanoate Ethyl 4-chloro-3-oxobutanoate L-Glutamine Glycine

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Race self-orthogonal relations of normal bases

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FINITE FIELDS AND THEIR APPLICATIONS 2015年 35卷 284-317页

作者： Zhang, Xiyong Huang, Weiwei Chu, Quanmei Han, Wenbao State Key Lab Math Engn & Adv Comp Wuxi 214215 Peoples R China Zhengzhou Informat Sci & Technol Inst Zhengzhou 450002 Peoples R China Sci & Technol Informat Assurance Lab Beijing 100072 Peoples R China

Normal bases with specific trace self-orthogonal relations over finite fields have been found to be very useful for many fast arithmetic computations, especially when the extensions of finite fields have no self-dual normal basis. Recent work in [1] has given the necessary and sufficient conditions for the existence of normal bases of GF(2(n)) with a prescribed trace vector when n is odd or n is a power of two. However, the methods in [1] cannot work in general cases. In this paper, using methods different from [1], we give a complete characterization of the trace self-orthogonal relations of arbitrary normal bases. Furthermore, we provide a combination method to construct normal elements with the prescribed trace vectors. These generalize the results in [1] to general cases. The main result of this paper is shown as follows. Let a = (a(0), a(1), ... , a(n-1)) be a prescribed n-vector over GF(q), with corresponding polynomial f(a)(x) = Sigma(n-1)(i=0) a(i)x(i). We present that there exists a normal element a of GF(q(n)) over GF(q), with trace vector a, such that a(i) = Tr-qn vertical bar q(alpha(1)+q(iota)) for all 0 <= i <= n-1, if and only if a(i) = a(n-i) for all 1 <= i <= n-1 and 1) when q is odd, f(a)(x) is prime to x(n) - 1;f(a)(1) is a quadratic residue in GF(q);for even n, if f(a)(-1) not equal 0, then f(a)(-1) is not a quadratic residue in GF(q);2) when q is even, f(a)(x) is prime to x(n) - 1;for even n, a(n/2) = 0 and if 4 vertical bar n, then Tr-q vertical bar 2(Sigma(n/4-1)(i=0) a(0-1) a(2i+1)) = 1. (C) 2015 Elsevier Inc. All rights reserved.

关键词： Normal basis Trace self-orthogonal Reciprocal polynomial Quadratic residue

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GPU parallelization of unstructured/hybrid grid ALE multigrid unsteady solver for moving body problems

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COMPUTERS & FLUIDS 2015年 110卷 122-135页

作者： Ma, Wenpeng Lu, Zhonghua Zhang, Jian Chinese Acad Sci Comp Network Informat Ctr Supercomp Ctr CAS Beijing 100190 Peoples R China State Key Lab Math Engn & Adv Comp Wuxi 214125 Peoples R China

Graphics Processing Units (GPUs) are currently being used to accelerate Computational Fluid Dynamics (CFD) codes and many GPU based CFD solvers have already showed that GPUs have great capabilities in numerical simulations. The development and validation of an unstructured/hybrid grid ALE (Arbitrary Lagrangian-Eulerian) multigrid unsteady solver on the GPU for moving body problems are present. This GPU based unsteady solver consists of two modules. A BICGSTAB based mesh deformation module which updates the mesh nodes to new positions as the interfaces of bodies move, and a geometrical multigrid (GMG) RANS (Reynolds-Averaged Navier-Stokes) solver which manages the flow computation using the dual time stepping approach. The GPU implementation and optimization for this two modules are discussed, respectively. Both 2D and 3D validation cases are carried out to analyze the accuracy and efficiency of this solver. The GPU results obtained agree well with the experimental measurements, as well as the numerical solutions presented by other researchers. A mixed MPI-CUDA implementation makes the unsteady flow solver capable of running on a multi-GPU cluster that consists of a set of GPUs and CPUs. Both the strong and weak scalability of the code are investigated on a heterogeneous computing platform. (C) 2014 Elsevier Ltd. All rights reserved.

关键词： Graphics Processing Units (GPUs) Unstructured/hybird grid Multigrid Mesh deformation

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Thread-Aware Adaptive Prefetcher on Multicore Systems: Improving the Performance for Multithreaded Workloads

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ACM TRANSACTIONS ON ARCHITECTURE AND CODE OPTIMIZATION 2016年第1期13卷 1–25页

作者： Liu, Peng Yu, Jiyang Huang, Michael C. Zhejiang Univ State Key Lab Math Engn & Adv Comp Hangzhou 310027 Peoples R China Zhejiang Univ Coll Informat Sci & Elect Engn Hangzhou 310027 Peoples R China State Key Lab Math Engn & Adv Comp Wuxi 214125 Peoples R China Huawei Technol Co Ltd Dept Shannon Lab Hangzhou 310051 Zhejiang Peoples R China Univ Rochester Dept Elect & Comp Engn 601 Elmwood Ave Rochester NY 14627 USA

Most processors employ hardware data prefetching techniques to hide memory access latencies. However, the prefetching requests from different threads on a multicore processor can cause severe interference with prefetching and/or demand requests of others. The data prefetching can lead to significant performance degradation due to shared resource contention on shared memory multicore systems. This article proposes a thread-aware data prefetching mechanism based on low-overhead runtime information to tune prefetching modes and aggressiveness, mitigating the resource contention in the memory system. Our solution has three new components: (1) a self-tuning prefetcher that uses runtime feedback to dynamically adjust data prefetching modes and arguments of each thread, (2) a filtering mechanism that informs the hardware about which prefetching request can cause shared data invalidation and should be discarded, and (3) a limiter thread acceleration mechanism to estimate and accelerate the critical thread which has the longest completion time in the parallel region of execution. On a set of multithreaded parallel benchmarks, our thread-aware data prefetching mechanism improves the overall performance of 64-core system by 13% over a multimode prefetch baseline system with two-level cache organization and conventional modified, exclusive, shared, and invalid-based directory coherence protocol. We compare our approach with the feedback directed prefetching technique and find that it provides 9% performance improvement on multicore systems, while saving the memory bandwidth consumption.

关键词： Design Algorithms Performance Data prefetcher thread-aware self-tuning multithreaded multicore

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A PAM-4 Adaptive Analog Equalizer with Decoupling Control Loops for 25-Gb/s CMOS Serial-Link Receiver 28

A PAM-4 Adaptive Analog Equalizer with Decoupling Control Lo...

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IEEE International System on Chip Conference (SOCC)

作者： Li, Shunbin Liu, Peng Wang, Weidong Fang, Xing Wu, Dong Xie, Xianghui Zhejiang Univ Coll Informat Sci & Elect Engn Hangzhou 310027 Zhejiang Peoples R China State Key Lab Math Engn & Adv Comp Wuxi 214125 Peoples R China

ISBN: (纸本)9781467390941

PAM-4 signaling is an effective solution for highspeed CMOS serial-link transceivers, but it suffers from the difficulty of signal regeneration in analog front-end owning to its multi-level characteristics. An adaptive analog equalizer with decoupling control loops is proposed to address the nonlinearity of amplifiers. A low-frequency gain invariant equalizer and a golden signal generator are designed to serve boost and swing control loops, respectively. An integrating charge pump is employed to improve the convergence performance of receiver. Transistor-level simulation results show that the proposed adaptive analog equalizer in 40-nm CMOS technology can recover 25 Gb/s random data transmitted over a 29.8 inches Megtron6 printed circuit board (PCB) copper channel.

关键词： Printed circuit boards

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Thread-aware adaptive prefetcher on multicore systems: Improving the performance for multithreaded workloads

Thread-aware adaptive prefetcher on multicore systems: Impro...

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作者： Liu, Peng Yu, Jiyang Huang, Michael C. College of Information Science and Electronic Engineering Zhejiang University Hangzhou310027 China State Key Laboratory of Mathematical Engineering and Advanced Computing Wuxi214125 China Department of Shannon Lab. Huawei Technologies Co. Ltd. Hangzhou310051 China Department of Electrical and Computer Engineering University of Rochester RochesterNY14627-0231 United States

Most processors employ hardware data prefetching techniques to hide memory access latencies. However, the prefetching requests from different threads on a multicore processor can cause severe interference with prefetching and/or demand requests of others. The data prefetching can lead to significant performance degradation due to shared resource contention on shared memory multicore systems. This article proposes a thread-aware data prefetching mechanism based on low-overhead runtime information to tune prefetching modes and aggressiveness, mitigating the resource contention in the memory system. Our solution has three new components: (1) a self-tuning prefetcher that uses runtime feedback to dynamically adjust data prefetching modes and arguments of each thread, (2) a filtering mechanism that informs the hardware about which prefetching request can cause shared data invalidation and should be discarded, and (3) a limiter thread acceleration mechanism to estimate and accelerate the critical thread which has the longest completion time in the parallel region of execution. On a set of multithreaded parallel benchmarks, our thread-aware data prefetchingmechanism improves the overall performance of 64-core system by 13% over a multimode prefetch baseline system with two-level cache organization and conventional modified, exclusive, shared, and invalid-based directory coherence *** compare our approach with the feedback directed prefetching technique and find that it provides 9% performance improvement on multicore systems, while saving the memory bandwidth consumption.

关键词： Benchmarking

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Iodine-catalyzed ammoxidation of methyl arenes

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CHEMICAL COMMUNICATIONS 2015年第24期51卷 5085-5088页

作者： Guo, Songjin Wan, Gen Sun, Song Jiang, Yan Yu, Jin-Tao Cheng, Jiang Changzhou Univ Sch Petrochem Engn Jiangsu Key Lab Adv Catalyt Mat & Technol Changzhou 213164 Peoples R China Changzhou Univ Jiangsu Prov Key Lab Fine Petrochem Engn Changzhou 213164 Peoples R China Nanjing Univ State Key Lab Coordinat Chem Nanjing 210093 Jiangsu Peoples R China

The development of organic transformation using cheap and readily available substrates under mild conditions will be pivotal for green and sustainable synthetic organic chemistry. Concerning our continued interest in the cyanation reaction, a metal-free direct ammoxidation of readily available methyl arenes leading to nitriles was established under mild conditions. A series of aryl methanes especially heteroaryl methanes (30 examples) were applicable in moderate to good yields with good functionality tolerance.

关键词： DIRECT OXIDATIVE CONVERSION COPPER-MEDIATED CYANATION H BOND-CLEAVAGE C-H METAL-FREE DIRECT TRANSFORMATION ARYL ISONITRILES NITRILES C(SP(3))-H AMINES

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Impact of Optical Hop Constraints on the IP/MPLS-over-WSON Networks CAPEX

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China Communications 2015年第11期12卷 112-118页

作者： LIU Fengqing Jaume Comellas School of Opto-Electronic Engineering Nanjing University of Posts and Telecommunications Dept.of Signal Theory and Communications Universitat Politècnica de Catalunya Barcelona

In this work,the impact of hop constraints on the CAPEX of multi-layer IP/MPLS over WSON networks is evaluated under different scenarios. By routing lightpaths with different number of transparent hops,the cost of networks varies significantly. This effect is thoroughly analyzed with a heuristic algorithm for different network topologies belonging to some European network operators. The main conclusion extracted is that limiting the transparent reach in such multi-layer networks can give a good tradeoff between CAPEX of IP/MPLS networks and WSON networks,and even lead to signifi cant savings in CAPEX when compared to longer lightpaths routing strategies.

关键词： IP/MPLS over WSON networks optical hop constraints CAPEX heuristics

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Preparation of ZIF-69 membranes for gasoline vapor recovery

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JOURNAL OF POROUS MATERIALS 2015年第5期22卷 1195-1203页

作者： Wu, Qigang Xu, Rong Li, Jing Zhang, Qi Zhong, Jing Huang, Weiqiu Gu, Xuehong Changzhou Univ Sch Petrochem Engn Jiangsu Key Lab Adv Catalyt Mat & Technol Changzhou 213164 Peoples R China Changzhou Univ Sch Petr Engn Changzhou 213016 Peoples R China Nanjing Univ Technol State Key Lab Mat Oriented Chem Engn Nanjing 210009 Jiangsu Peoples R China

The compact ZIF-69 membranes have been prepared by seeded growth method for the recovery of gasoline vapor which is a major challenge in the petrochemical industry. The membrane performances for separating N-2/n-alkane mixtures at various operating conditions (e.g. trans-membrane pressure difference, operating temperature, feed concentration, and stage cut) were systematically investigated. The highest separation factor was 2.60 with the corresponding permeance of 5.02 x 10(-8) mol/(m(2) s Pa) for the N-2/n-C6H14 model mixtures. Moreover, the effects of n-alkane components (n-C5H12, n-C6H14, and n-C7H16) on the separation performances were studied, and the separation factors followed alpha(N-2/n-C7H16) > alpha(N-2/n-C6H14) > alpha(N-2/n-C5H12), due to the different adsorption capacities of n-alkanes on ZIF-69 materials. The present work demonstrates that the ZIF-69 membrane is a highly promising candidate for the application in gasoline vapor recovery.

关键词： ZIF-69 membrane N-2/alkane (C5-C7) separation Gasoline vapor recovery Operating condition

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