A^2-Net: Molecular Structure Estimation from Cryo-EM Density Volumes

Constructing of molecular structural models from Cryo-Electron Microscopy (Cryo-EM) density volumes is the critical last step of structure determination by Cryo-EM technologies. Methods have evolved from manual construction by structural biologists to perform 6D translation-rotation searching, which is extremely compute-intensive. In this paper, we propose a learning-based method and formulate this problem as a vision-inspired 3D detection and pose estimation task. We develop a deep learning framework for amino acid determination in a 3D Cryo-EM density volume. We also design a sequence-guided Monte Carlo Tree Search (MCTS) to thread over the candidate amino acids to form the molecular structure. This framework achieves 91% coverage on our newly proposed dataset and takes only a few minutes for a typical structure with a thousand amino acids. Our method is hundreds of times faster and several times more accurate than existing automated solutions without any human intervention.Comment: 8 pages, 5 figures, 4 table

A Novice Method for Calibrating the Transient Model of an Automotive HVAC System

A novice method for calibrating the transient model of an automotive HVAC system is presented in this paper. Transient models can be of great importance in the development process of automotive HVAC control algorithms, especially model based ones, as it saves both time and effort. However, the calibration process is usually difficult and relies heavily on experience due to the complexity of the model. A set of customized measurement tools, which consists of several wireless temperature and humidity sensors and an OBD dongle, is used to capture time series data related to the HVAC system during normal driving. Parts of the time series data are then fed into an optimization algorithm to generate a cost function, which can be minimized when the measured data correspond to the simulation data generated by the transient model, while other parts of the data are remained for the validation step. A sensitivity analysis is then performed to find out which parameters in the HVAC transient model need to be optimized to calibrate the model. As the transient model is a physical network model which can be generally considered as a set of differential and algebraic equations, this presented method reduces the calibration process of a complex physical model into solving a common optimization problem. Therefore, various optimization algorithms and tools can be applied. The method is developed and tested during the modeling process of an automotive HVAC system. The efficiency of the modelling process is improved while the calibration results fit better with the measured data.

Research on the Operating Characteristics of Floor Heating System with Residential EVI Air Source Heat Pump in China

Air source heat pump is considered a commendatory way to help solve the environmental problems resulting from coal-fired heating, especially in the cold region of China. The heat pump uses air as low-grade heat source, so the atmospherical temperature plays a key role in the operating performance of units. And the technology of economized vapor injection (EVI) is used to improve the performance in the low temperature condition. Beijing is one of the most typical cities in China cold region. Therefore, this paper took a residence in Beijing as the test site. A long-term and high-frequency monitoring was performed to investigate the operating characteristics and heating effect of floor heating system with EVI air source heat pump, and the economy was also analyzed. Equivalent carbon dioxide emission was also calculated to evaluate the carbon dioxide emission of such a heating system from cradle to grave. The results showed that the heating seasonal performance factor (HSPF) of the heating system in Beijing was 3.28, and the running condition was stable on the premise of satisfying the heating need of uses. Attentions were also paid to the behavior of residents. The irregularity revealed the apparent need and the energy saving awareness, which directly affected the power consumption

Literature review of condensation and evaporation of R290

Nowadays, an increasing attention in environmental issues including the global warming effect and ozone layer depletion has been attracted. R22 is urged to be ruled out until 2020 and 2030 for developed and developing countries. R290 (propane) has been regarded as a promising alternative refrigerant for the air-conditionings. Comparing to other alternatives, R290 has zero ozone depletion potential and negligible GWP. However, R290 has different thermo-physical properties than conventional refrigerants and it would influence the application in tubes such as shear forces, gravity and surface tension. The condensation and evaporation behavior of R290 would has a great effect in designing suitable heat exchanger for R290. In recent years, researchers have made great efforts in studying different working fluids behaviors and multiple semi-empirical correlations have been established to predict the heat transfer and pressure drop. However, the study about R290 behavior is very limited. According to the past experiences in condensation and evaporation studies, the semi-empirical models may be not very accurate in the working conditions outside the range where they are established. This paper presents a detailed review of research work done on the condensation and evaporation of R290. It also gives a comparison between R290 and other working fluid behavior and makes a summarization on predicting correlations for R290 heat transfer and pressure drop. This paper is a starting point for future R290 studies and R290 applications in air conditioning systems.

Experimental Study of Fouling Performance of Air Conditioning System with Microchannel Heat Exchanger

Microchannel heat exchanger (MCHX) has many advantages compared with traditional heat exchanger. The research and application of it also develop fast in recent years. However, in the domestic air conditioning field, it has not been widely used yet. One of the obstacles is the dust fouling of the outside condenser. The affect of dust fouling problem on air conditioning systems with louver fin and wavy fin was researched in this article. The results show the fouling problem of the MCHX can cause drastically performance degradation of the system, the cooling capacity decreased by 23% and 17.2%, the energy consumption increased by 52.5% and 28.4%, and COP decreased by 49.5% and 35.6% for air condition systems with louver fin and wavy fin MCHX respectively after they run for 3 months in the factory environment. Based on this situation, a fan blowback control strategy was introduced into the air conditioning system. After adding the control strategy, the cooling capacity only decreased by 5.5% and 2%, the energy consumption increased by 7.8% and 2.3%, and COP decreased by 12.3% and 4.3% for the systems with louver fin and wavy fin MCHX respectively 3 months later

LCCP Analysis of Energy-Saving Effect of Defaulting to Recirculated Cabin Air in EV Mobile Air Conditioning System

The climate control load is the most significant auxiliary loads present in vehicles today. The peak climate control load of an AC system in sedan can be as large as the engine input power. As the attention on vehicle energy economy is rising worldwide, the energy-saving of mobile air conditioning is becoming more and more important. Most mobile AC systems nowadays draw air from outside the vehicle and cool it to the desired comfort level inside the vehicle. Lots of energy is wasted during this process due to continuously cooling the hotter outside air instead of cooling the “cooler†inside air. Compared to that, defaulting to recirculated cabin air will certainly be energy-saving. Though some studies have revealed the energy saving effectiveness under bench test conditions, it is still unclear how much energy can be saved when mobile AC systems are operated in different climates and driving patterns. The GREEN-MAC-LCCP tool is modelled to evaluate the life cycle climate performance of mobile AC system, and it is well-accepted. This tool is capable of analysing the full cycle of greenhouse gas emissions (GHG) of alternative refrigerant systems and different system structures. In this article, the energy-saving effect of defaulting to recirculated cabin air is evaluated using GREEN-MAC-LCCP. It is found that 7%-48% of energy saving can be achieved under the calculated climate conditions

Distributed tracking control of leader-follower multi-agent systems under noisy measurement

In this paper, a distributed tracking control scheme with distributed estimators has been developed for a leader-follower multi-agent system with measurement noises and directed interconnection topology. It is supposed that each follower can only measure relative positions of its neighbors in a noisy environment, including the relative position of the second-order active leader. A neighbor-based tracking protocol together with distributed estimators is designed based on a novel velocity decomposition technique. It is shown that the closed loop tracking control system is stochastically stable in mean square and the estimation errors converge to zero in mean square as well. A simulation example is finally given to illustrate the performance of the proposed control scheme.Comment: 8 Pages, 3 figure

Automated identification and quantification of myocardial inflammatory infiltration in digital histological images to diagnose myocarditis

This study aims to develop a new computational pathology approach that automates the identification and quantification of myocardial inflammatory infiltration in digital HE-stained images to provide a quantitative histological diagnosis of myocarditis.898 HE-stained whole slide images (WSIs) of myocardium from 154 heart transplant patients diagnosed with myocarditis or dilated cardiomyopathy (DCM) were included in this study. An automated DL-based computational pathology approach was developed to identify nuclei and detect myocardial inflammatory infiltration, enabling the quantification of the lymphocyte nuclear density (LND) on myocardial WSIs. A cutoff value based on the quantification of LND was proposed to determine if the myocardial inflammatory infiltration was present. The performance of our approach was evaluated with a five-fold cross-validation experiment, tested with an internal test set from the myocarditis group, and confirmed by an external test from a double-blind trial group. An LND of 1.02/mm2 could distinguish WSIs with myocarditis from those without. The accuracy, sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) in the five-fold cross-validation experiment were 0.899 plus or minus 0.035, 0.971 plus or minus 0.017, 0.728 plus or minus 0.073 and 0.849 plus or minus 0.044, respectively. For the internal test set, the accuracy, sensitivity, specificity, and AUC were 0.887, 0.971, 0.737, and 0.854, respectively. The accuracy, sensitivity, specificity, and AUC for the external test set reached 0.853, 0.846, 0.858, and 0.852, respectively. Our new approach provides accurate and reliable quantification of the LND of myocardial WSIs, facilitating automated quantitative diagnosis of myocarditis with HE-stained images.Comment: 21 pages,5 figures,6 Tables, 25 reference

Anomalous thermal Hall effect and anomalous Nernst effect of CsV3_{3}Sb5_{5}

Motived by time-reversal symmetry breaking and giant anomalous Hall effect in kagome superconductor \textit{A}V$_3$Sb$_5$ (\textit{A} = Cs, K, Rb), we carried out the thermal transport measurements on CsV$_3$Sb$_5$. In addition to the anomalous Hall effect, the anomalous Nernst effect and the anomalous thermal Hall effect emerge. Interestingly, the longitudinal thermal conductivity $\kappa_{xx}$ largely deviates from the electronic contribution obtained from the longitudinal conductivity $\sigma_{xx}$ by the Wiedemann-Franz law. In contrast, the thermal Hall conductivity $\kappa_{xy}$ is roughly consistent with the Wiedemann-Franz law from electronic contribution. All these results indicate the large phonon contribution in the longitudinal thermal conductivity. Moreover, the thermal Hall conductivity is also slightly greater than the theoretical electronic contribution, indicating other charge neutral contributions. More than that, the Nernst coefficient and Hall resistivity show the multi-band behavior with possible additional contribution from Berry curvature at the low fields