@article{zhou_liu_yuan_2018, title={Kinetic modeling of lactic acid and acetic acid effects on butanol fermentation by Clostridium saccharoperbutylacetonicum}, volume={226}, ISSN={["1873-7153"]}, DOI={10.1016/j.fuel.2018.04.019}, abstractNote={Abstract Kinetic models of acetone-butanol-ethanol fermentation with lactic acid or acetic acid addition were developed and implemented in COPASI for metabolic analysis of acid effects on butanol synthesis. The simulation results were compared with experimental data in batch cultures of Clostridium saccharoperbutylacetonicum under various initial lactic acid or acetic acid concentrations. High average correlation coefficients (r2) of over 0.92 between simulation and experimental results were obtained in both models. According to parameter scan in both models, reducing glucose uptake rate, increasing the conversion rate from glyceraldehyde 3-phosphate (G3P) to pyruvate or from butyryl-CoA (BCoA) to butanol would enhance butanol production. On the other hand, increasing consumption rate of supplemented lactic acid or acetic acid could also contribute to improved butanol synthesis. Overall, the developed kinetic models can accurately predict the dynamic behavior of metabolites in ABE fermentation with lactic acid or acetic acid addition and consequently identify genetic manipulation strategies for higher bio-butanol production in the future.}, journal={FUEL}, author={Zhou, Quan and Liu, Ying and Yuan, Wenqiao}, year={2018}, month={Aug}, pages={181–189} }
 @article{zhou_zheng_yuan_2018, title={Modeling Butanol Synthesis in Xylose by Clostridium saccharoperbutylacetonicum}, volume={13}, ISSN={["1930-2126"]}, DOI={10.15376/biores.13.4.7270-7280}, abstractNote={To examine the effect of xylose concentration on butanol synthesis by Clostridium saccharoperbutylacetonicum, a kinetic model of acetone-butanol-ethanol fermentation in the media with various xylose concentrations (40 g/L to 60 g/L) was developed and implemented in COPASI. Batch fermentation experiments were conducted to feed and validate the model, and the highest butanol production was achieved in 45 g/L xylose medium. Strong correlations (R2 > 0.91) between model simulation and experimental results were obtained. The modeling results suggested that the reaction rates in R6 (from acetate to acetyl-CoA), R8 (from acetyl-CoA to acetoacetyl-CoA), R9 (from acetoacetyl-CoA to butyryl-CoA), R10 (from butyryl-CoA to butanol), R14 (from butyrate to butyryl-CoA), and R20 (xylose consumption) were higher in groups with an initial xylose of 45 g/L, 50 g/L, or 55 g/L than those in groups with 40 g/L or 60 g/L xylose. In contrast, the reaction rates in R13 (from butyryl-CoA to butyrate) and R16 (from biomass to inactive cells) were lower in groups with initial xylose of 45 g/L, 50 g/L, or 55 g/L than those in groups with 40 g/L or 60 g/L xylose, which indicated that when initial xylose concentration changed, those reactions were affected, which resulted in different butanol syntheses.}, number={4}, journal={BIORESOURCES}, author={Zhou, Quan and Zheng, Huabao and Yuan, Wenqiao}, year={2018}, pages={7270–7280} }
 @article{liu_geng_zhou_yuan_2018, title={The effect of furfural and 5-hydroxymethyl furfural on butyric acid fermentation by Clostridium tyrobutyricum}, volume={93}, DOI={10.1002/jctb.5439}, abstractNote={Abstract BACKGROUND Potential inhibitory effects of byproducts from lignocellulosic hydrolysis process, including furfural and 5‐hydroxymethyl furfural (HMF), on butyric acid fermentation by Clostridium tyrobutyricum were studied by adding furfural (0, 0.3, 0.6, 0.9 and 1.2 g L ‐1 ) and HMF (0, 0.6, 1.2, 1.8 and 2.4 g L ‐1 ) separately into the xylose medium. RESULTS Increases in furfural or HMF concentration led to reduced butyric acid productivity. Delays on cell growth and xylose consumption were also noticed with increasing concentrations of furfural and HMF. Complete inhibition of C. tyrobutyricum fermentation was observed at 1.2 g L ‐1 of furfural, while HMF showed less severe effects, and that C. tyrobutyricum could tolerate up to 2.4 g L ‐1 of HMF. Both furfural and HMF could be metabolized by C. tyrobutyricum . CONCLUSION Furfural at concentrations higher than 0.3 g L ‐1 and HMF at concentrations higher than 0.6 g L ‐1 can significantly inhibit the butyric acid fermentation of C. tyrobutyricum , and furfural had more severe effects in terms of cell growth and metabolisms. © 2017 Society of Chemical Industry}, number={3}, journal={Journal of Chemical Technology and Biotechnology}, author={Liu, Y. and Geng, Y. X. and Zhou, Q. and Yuan, Wenqiao}, year={2018}, pages={849–854} }
 @article{zhou_dai_2007, title={Asymptotic analysis on the interaction between spatial diversity and multiuser diversity in wireless networks}, volume={55}, ISSN={["1941-0476"]}, DOI={10.1109/TSP.2007.896059}, abstractNote={Spatial diversity and multiuser diversity attract much research interest recently. In this paper, through asymptotic analysis of the average system capacity and scheduling gain, we investigate the cross-layer interaction between these two forms of diversity in wireless networks. Rigorous proofs and necessarily stronger results in terms of convergence are provided for some intuitions in this area. Equally important, explicit expressions of scheduling gain and average system capacity in various circumstances that reveal interconnections and fundamental tradeoffs among key system parameters are given, which afford us some insights in system design. Our results are general enough to cover many practical scenarios of interest.}, number={8}, journal={IEEE TRANSACTIONS ON SIGNAL PROCESSING}, author={Zhou, Quan and Dai, Huaiyu}, year={2007}, month={Aug}, pages={4271–4283} }
 @article{zhou_dai_2006, title={Asymptotic analysis in MIMO MRT/MRC systems}, ISSN={["1687-1499"]}, DOI={10.1155/wcn/2006/45831}, abstractNote={Through the analysis of the probability density function of the squared largest singular value of a complex Gaussian matrix at the origin and tail, we obtain two asymptotic results related to the multi-input multi-output (MIMO) maximum-ratio-transmission/maximum-ratio-combining (MRT/MRC) systems. One is the asymptotic error performance (in terms of SNR) in a single-user system, and the other is the asymptotic system capacity (in terms of the number of users) in the multiuser scenario when multiuser diversity is exploited. Similar results are also obtained for two other MIMO diversity schemes, space-time block coding and selection combining. Our results reveal a simple connection with system parameters, providing good insights for the design of MIMO diversity systems.}, journal={EURASIP JOURNAL ON WIRELESS COMMUNICATIONS AND NETWORKING}, author={Zhou, Quan and Dai, Huaiyu}, year={2006} }
 @inproceedings{zhou_dai_zhang_2006, title={Joint Tomlinson-Harashima Precoding and Scheduling for Multiuser MIMO with Imperfect Feedback}, DOI={10.1109/wcnc.2006.1696462}, abstractNote={In this paper, we propose a crosslayer approach that explores Tomlinson-Harashima precoding (THP) at the physical layer to reduce the multiuser scheduling burden at the MAC layer, and improves the sum rate of the downlink multiuser MIMO system. Our proposed scheme is further evaluated with imperfect feedback, obtained by the long range prediction (LRP) technique. Compared to some existing scheduling schemes, the proposed scheme approaches the performance upper bound in certain scenarios, while incurring much less computation complexity. Significant gains are still maintained with imperfect channel state information (CSI), fed back at a rate much lower than the data rate}, booktitle={2006 ieee wireless communications and networking conference (wcnc 2006), vols 1-4}, author={Zhou, Q. A. and Dai, H. Y. and Zhang, H. Y.}, year={2006}, pages={1233–1238} }
 @article{zhou_dai_2006, title={Joint antenna selection and link adaptation for MIMO systems}, volume={55}, ISSN={["1939-9359"]}, DOI={10.1109/TVT.2005.861211}, abstractNote={Multi-input multi-output (MIMO) systems, with multiple antennas at both the transmitter and the receiver, are anticipated to be widely employed in future wireless networks due to their predicted tremendous system capacity. To protect the transmitted data against random channel impairment, it is desirable to consider link adaptation, such as rate adaptation and power control, to improve the system performance and guarantee certain quality of service. Based on the observation that link adaptation and antenna selection problems are often coupled, we propose a joint antenna subset selection and link adaptation study for MIMO systems. After the formulation of the multidimensional joint optimization problem, the main contribution of this paper lies in the design of efficient algorithms approaching the optimal solution for both uncorrelated and correlated MIMO channels. Specifically, we propose one simplified antenna selection and link adaptation rule based on the expected optimal number of active antennas for uncorrelated MIMO with Rayleigh fading and one for correlated MIMO channels only based on the slowly varying channel correlation information. Our proposed algorithms are verified through numerical results, demonstrating significant gains over traditional MIMO signaling, while feasible for practical implementation.}, number={1}, journal={IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY}, author={Zhou, Q and Dai, HY}, year={2006}, month={Jan}, pages={243–255} }
 @article{zhang_dai_zhou_hughes_2006, title={On the diversity order of spatial multiplexing systems with transmit antenna selection: A geometrical approach}, volume={52}, ISSN={["1557-9654"]}, DOI={10.1109/TIT.2006.885531}, abstractNote={In recent years, the remarkable ability of multiple-input-multiple-output (MIMO) wireless communication systems to provide spatial diversity or multiplexing gains has been clearly demonstrated. For MIMO diversity schemes, it is well known that antenna selection methods that optimize the postprocessing signal-to-noise ratio (SNR) can preserve the diversity order of the original full-size MIMO system. On the other hand, the diversity order achieved by antenna selection in spatial multiplexing systems, especially those exploiting practical coding and decoding schemes, has not thus far been rigorously analyzed. In this paper, a geometrical framework is proposed to theoretically analyze the diversity order achieved by transmit antenna selection for separately encoded spatial multiplexing systems with linear and decision-feedback receivers. When two antennas are selected from the transmitter, the exact achievable diversity order is rigorously derived, which previously only appears as conjectures based on numerical results in the literature. If more than two antennas are selected, we give lower and upper bounds on the achievable diversity order. Furthermore, the same geometrical approach is used to evaluate the diversity-multiplexing tradeoff in spatial multiplexing systems with transmit antenna selection}, number={12}, journal={IEEE TRANSACTIONS ON INFORMATION THEORY}, author={Zhang, Hongyuan and Dai, Huaiyu and Zhou, Quan and Hughes, Brian L.}, year={2006}, month={Dec}, pages={5297–5311} }