Reexamining charmless B\to PV decays in QCD factorization approach

Using the QCD factorization approach, we reexamine the two-body hadronic charmless $B$-meson decays to final states involving a pseudoscalar~($P$) and a vector~($V$) meson, with inclusion of the penguin contractions of spectator-scattering amplitudes induced by the $b\to D g^\ast g^\ast$~(where $D=d$ or $s$, and $g^\ast$ denotes an off-shell gluon) transitions, which are of order $\alpha_s^2$. Their impacts on the CP-averaged branching ratios and CP-violating asymmetries are examined. We find that these higher order penguin contraction contributions have significant impacts on some specific decay modes. Since $B\to \pi K^{\ast}$, $K \rho$ decays involve the same electro-weak physics as $B\to \pi K$ puzzles, we present a detailed analysis of these decays and find that the five R-ratios for $B\to \pi K^{\ast}$, $K \rho$ system are in agreement with experimental data except for $R(\pi K^*)$. Generally, these new contributions are found to be important for penguin-dominated $B\to PV$ decays.Comment: 45 pages, 12 figures. Theoretical uncertainties considered. Gauge invariance proved. Version to appear in PR

Consumer Confidence, News and Consumption Stimulation

In the Chinese urban data, there is a stronger relationship between consumer behavior (measured by consumption income ratio or cy ratio) and consumer confidence (measured by Consumer Confidence Index or CCI), which implies expectation about the future plays an important role in domestic demand. In our paper, a structural VAR method (based on Beaudry&Portier 2006 AER) is employed to identify the news shock about three markets including housing, education and medical care. We also extract the components in CCI about news shocks for those three sectors. After that, we conduct regression on cy ratio against those components extracted from CCI, and find that the expectation on housing accounts more importance in consumption, education takes a second place and medical care has little effect.News Driven Expectation; Chinese Consumption Behavior; Structural VAR

Research Summary on Subway Noise and Controlling in China

During the operation of the subway, if the noise in the carriage is large, it will cause passengers to suffer from hearing impairment, headache, brain swelling, insomnia, memory loss, and other symptoms, threatening the health of passengers. This paper summarizes the sound source, propagation path, main control methods, research status, and development trend of subway noise, and puts forward the methods and ideas of subway noise control, which has reference significance for subway noise control and optimization research

Learning Deep Generative Models with Annealed Importance Sampling

Variational inference (VI) and Markov chain Monte Carlo (MCMC) are two main approximate approaches for learning deep generative models by maximizing marginal likelihood. In this paper, we propose using annealed importance sampling for learning deep generative models. Our proposed approach bridges VI with MCMC. It generalizes VI methods such as variational auto-encoders and importance weighted auto-encoders (IWAE) and the MCMC method proposed in (Hoffman, 2017). It also provides insights into why running multiple short MCMC chains can help learning deep generative models. Through experiments, we show that our approach yields better density models than IWAE and can effectively trade computation for model accuracy without increasing memory cost

Spike‐Timing‐Dependent Plasticity in Memristors

The spike‐timing‐dependent plasticity (STDP) characteristic of the memristor plays an important role in the development of neuromorphic network computing in the future. The STDP characteristics were observed in different memristors based on different kinds of materials. The investigation regarding the influences of device hysteresis characteristic, the initial conductance of the memristors, and the waveform of the voltage pulses applied to the memristor as preneuron voltage spike and postneuron voltage spike on the STDP behavior of memristors are reviewed

Dynamic Management of Hardware Multi-threading for Network Processors

AbstractIn this paper, we presented a dynamic management mechanism of hardware multi-threading for pipelined hardware multi-threading architecture. And a set of special instructions are provided. In view of the workload and traffic of network are uncertainty, the dynamic multi-threading architecture in this paper can adaptively adjust processor performance according to the workload, and achieve the effective power savings

Reducing process cost and CO2 emissions for extractive distillation by double-effect heat integration and mechanical heat pump

Double-effect heat integration and mechanical heat pump technique are investigated for the extractive distillation process of the acetone–methanol minimum boiling azeotropic mixture with entrainer water and compared from the economical view by the total annual cost (TAC) and environmental aspect by CO2 emissions. Firstly, A novel optimal partial heat integration (OPHI) process is proposed and optimized through the minimization of a newly defined objective function called OF2 that describes the energy consumption used per product unit flow rate and allows comparison with the literature direct partial and full heat integration processes. We find that the minimum TAC is not achieved by the full heat integration process as intuition, but by the new OPHI process. Secondly, the vapour recompression (VRC) and bottom flash (BF) mechanical heat pump processes are evaluated with respect to energy and CO2 emissions. We proposed a new partial VRC and a new partial BF process in order to reduce the high initial capital cost of compressors. Overall the results show that compared to the conventional extractive distillation process the proposed OPHI process gives a 32.2% reduction in energy cost and a 24.4% saving in TAC while the full BF process has the best performance in environmental aspect (CO2 emissions reduce by 7.3 times)

Improved Design and Efficiency of the Extractive Distillation Process for Acetone–Methanol with Water

We show how thermodynamic insight can be used to improve the design of a homogeneous extractive distillation process, and we define an extractive efficiency indicator to compare the optimality of different designs. The case study is related to the separation of the acetone–methanol minimum boiling azeotrope with water. The process flow sheet includes both the extractive distillation column and the entrainer regeneration column. Insight from analysis of the ternary residue curve map and isovolatility curves shows that a lower pressure reduces the minimal amount of entrainer needed and increases the relative volatility of acetone–methanol in the extractive column. A 0.6 atm pressure is selected to enable the use of cheap cooling water in the condenser. We optimize the entrainer flow rate, adjusting both column reflux ratios and feed locations, by minimizing the total energy consumption per product unit. The total annualized cost (TAC) is calculated for all processes. Double-digit savings in energy consumption and in TAC are achieved compared to literature values. We then propose a novel efficiency indicator that describes the ability per tray of extractive section to discriminate the desired product between the top and the bottom of the extractive section. Shifting the feed trays’ locations improves the efficiency of the separation, even when less entrainer is used

Low pressure design for reducing energy cost of extractive distillation for separating Diisopropyl ether and Isopropyl alcohol

We show how reducing pressure can improve the design of a 1.0-1a mixture homogeneous extractive distillation process and we use extractive efficiency indicators to compare the optimality of different designs. The case study concerns the separation of the diisopropyl ether (DIPE)–isopropyl alcohol (IPA) minimum boiling azeotrope with heavy entrainer 2-methoxyethanol. We first explain that the unexpected energy cost OF decrease following an increase of the distillate outputs is due to the interrelation of the two distillate flow rates and purities and the entrainer recycling through mass balance when considering both the extractive distillation column and the entrainer regeneration column. Then, we find that for the studied case a lower pressure reduces the usage of entrainer and increases the relative volatility of DIPE–IPA for the same entrainer content in the extractive column. A 0.4 atm operating pressure is selected to enable the use of cheap cooling water in the condenser. We run an optimization of the entrainer flow rate, both columns reflux ratios, distillates and feed locations by minimizing the total energy consumption per product unit. Double digit savings in energy consumption are achieved while TAC is reduced significantly. An extractive efficiency indicator that describes the ability of the extractive section to discriminate the desired product between the top and the bottom of the extractive section of the extractive section is calculated for comparing and explaining the benefit of lowering pressure on the basis of thermodynamic insight