Research on Relationship between Possession of Private Vehicles and Air Quality in China

This paper deals with the relationship between possession of private vehicles and air quality, applying panel data model and based on the data in 31 provinces of China from 2003 to 2009. The research shows that there is hardly positive correlation between them in the provinces in China. On the contrary, the correlation between them is negative in most of the provinces. As a result, we conclude that private vehicles don’t cause serious air pollution and there must be other more essential factors that cause air pollution. Key words: Possession of private vehicles; Air quality; Panel data model Résumé: Cet article traite de la relation entre la possession de véhicules privés et la qualité de l'air, en utilisant le modèle de groupe de données et basé sur les données dans 31 provinces chinoises de 2003 à 2009. La recherche montre qu'il n'y a guère de corrélation positive entre eux dans les provinces en Chine. Au contraire, la corrélation entre eux est négative dans la plupart des provinces. En conséquence, nous concluons que les véhicules privés ne causent pas de pollution de l'air grave et il doit y avoir d'autres facteurs plus essentiels qui causent la pollution de l'air. Mots-clés: Possession de véhicules privés; Qualité de l'air; Modèle de groupe de donnée

Evaluation of the consolidation status of heavy oil sands through rock physics analysis: A case study from Fengcheng oilfield

Heavy oil is an important unconventional oil resource with huge availability worldwide, which also forms the primary oil source in Fengcheng oilfield, XinJiang, China. The elastic properties and consolidation status of heavy oil sands are of significant values as they can provide guidance for reservoir exploration and production. However, due to the lack of detailed rock physics investigation of the heavy oil sands in Fengcheng oilfield, the knowledge about their micro-scale elastic properties and consolidation status is still limited. Based on the well log data and laboratory measurements, we performed rock physics analysis of the heavy oil sands’ elastic properties. We first analyzed the well logs to determine the oil sands formations and then quantitatively delineated the relations between density, porosity, and velocity. Combining with laboratory measured data, we applied theoretical rock physics models to characterize the consolidation status of the heavy oil sands. Our results show that the oil sands in this area are poorly consolidated with a loose rock frame. Overall, this study highlights the micro-scale elastic properties of the heavy oil sands in Fengcheng oilfield and also reveals the consolidation status. It presents a method of integrating well log, laboratory data, and rock physics analysis to evaluate the consolidation status of heavy oil sands, which can facilitate the future detailed petrophysical analysis and provide important information for seismic characterization and drilling risk evaluation

Diffusion Conditional Expectation Model for Efficient and Robust Target Speech Extraction

Target Speech Extraction (TSE) is a crucial task in speech processing that focuses on isolating the clean speech of a specific speaker from complex mixtures. While discriminative methods are commonly used for TSE, they can introduce distortion in terms of speech perception quality. On the other hand, generative approaches, particularly diffusion-based methods, can enhance speech quality perceptually but suffer from slower inference speed. We propose an efficient generative approach named Diffusion Conditional Expectation Model (DCEM) for TSE. It can handle multi- and single-speaker scenarios in both noisy and clean conditions. Additionally, we introduce Regenerate-DCEM (R-DCEM) that can regenerate and optimize speech quality based on pre-processed speech from a discriminative model. Our method outperforms conventional methods in terms of both intrusive and non-intrusive metrics and demonstrates notable strengths in inference efficiency and robustness to unseen tasks. Audio examples are available online (https://vivian556123.github.io/dcem).Comment: Submitted to ICASSP 202

Drought losses in China might double between the 1.5 °C and 2.0 °C warming

We project drought losses in China under global temperature increase of 1.5 °C and 2.0 °C, based on the Standardized Precipitation Evapotranspiration Index (SPEI) and the Palmer Drought Severity Index (PDSI), a cluster analysis method, and “intensity-loss rate” function. In contrast to earlier studies, to project the drought losses, we predict the regional gross domestic product under shared socioeconomic pathways instead of using a static socioeconomic scenario. We identify increasing precipitation and evapotranspiration pattern for the 1.5 °C and 2.0 °C global warming above the preindustrial at 2020–2039 and 2040–2059, respectively. With increasing drought intensity and areal coverage across China, drought losses will soar. The estimated loss in a sustainable development pathway at the 1.5 °C warming level increases 10-fold in comparison with the reference period 1986–2005 and nearly threefold relative to the interval 2006–2015. However, limiting the temperature increase to 1.5 °C can reduce the annual drought losses in China by several tens of billions of US dollars, compared with the 2.0 °C warming

Design of a large-range rotary microgripper with freeform geometries using a genetic algorithm.

peer reviewedThis paper describes a novel electrostatically actuated microgripper with freeform geometries designed by a genetic algorithm. This new semiautomated design methodology is capable of designing near-optimal MEMS devices that are robust to fabrication tolerances. The use of freeform geometries designed by a genetic algorithm significantly improves the performance of the microgripper. An experiment shows that the designed microgripper has a large displacement (91.5 μm) with a low actuation voltage (47.5 V), which agrees well with the theory. The microgripper has a large actuation displacement and can handle micro-objects with a size from 10 to 100 μm. A grasping experiment on human hair with a diameter of 77 μm was performed to prove the functionality of the gripper. The result confirmed the superior performance of the new design methodology enabling freeform geometries. This design method can also be extended to the design of many other MEMS devices

Study on Man-machine Design of Armoured Vehicles Operation Space

This paper proposes an improved armoured vehicle control room based on ergonomic theory and computer-aided design technology to create efficiency by improving panel layout and seat design. Current design of existing control rooms that do not maximize ergonomics can create operator fatigue and user error. Optimal control room design was created by considering console size, console layout, and user seat dimensions and were entered into JACK software for simulation tests

Spatial Variability Analysis of Farmland Soil Infiltration Based on Model Parameters

Research on the variation of soil infiltration is helpful to analyze the mechanism of soil water movement in farmland. At the same time, soil infiltration characteristics affect the surface irrigation. Based on the field test data, this study simulated and analyzed the soil infiltration with three soil infiltration models (Kostiakov-Lewis model, Philip model and Horton model). The infiltration uncertainty of farmland soil are investigated, and proposed by using two random simulation methods (direct method and parameter mean method) of infiltration. The evaluated indicators are the interval size and its stability of cumulative infiltration amount changed with 95% confidence. The effects of different random simulations methods and three models on the infiltration process are compared and analyzed. Finally, the model and stochastic simulation method suitable for the infiltration characteristics of the farmland are determined. The results show that the correlation coefficients of the three models are all above 0.98, and there is no significant difference in fitting accuracy. In terms of the degree of spatial uncertainty (determined by standard deviation): direct method > parameter mean method, in which the combination of the Kostiakov-Lewis model and the parameter mean method have less uncertainty, and the combined simulation effect is better, it is more suitable for the simulation of soil infiltration at farmland scale

Alternative coulometric signal readout based on a solid-contact ion-selective electrode for detection of nitrate

Traditional potentiometric NO3--selective electrodes suffer from a fundamental limitation of the Nernst slope (59.1 mV/dec at 25 degrees C) due to the relationship between the potential and the logarithmic of ionic activity. Herein, a coulometric signal readout is proposed instead of the potentiometric response for detection of NCii based on an ordered mesoporous carbon (OMC)-based solid-contact ion-selective electrode (ISE). The mechanism for obtaining the coulometric signal is based on the electrical double layer capacitance of OMC compensating the potential change at the ion-selective membrane/solution interface during the measurements under the control of a constant applied potential. Under the optimized conditions, the coulometric signal for the OMC-based solid-contact NO3--ISE shows two linear responses in the activity range of 1.0 x 10(-6)-8.0 x 10(-6) M and 8.0 x 10(-6)-8.0 x 10(-4) M, and the detection limit is 4.0 x 10(-7) M (3 sigma/s). The proposed coulometric response also shows excellent reproducibility and stability in the presence of O-2 and CO2 and light on/off. Additionally, the coulometric response shows acceptable and reliable results for detection of NO3- in mineral water as compared to the traditional potentiometric response and the ion chromatography. This work provides a promising alternative signal readout for detection of ions by using solid-contact ion-selective electrodes. (C) 2020 Elsevier B.V. All rights reserved

Translating potentiometric detection into non-enzymatic amperometric measurement of H2O2

The developments of alternative signal readout strategies for the ion-selective electrodes (ISEs) are necessary in order to break through the limitation of the Nernst equation. In this work, a simple, convenient and easily operated strategy based on the non-enzymatic amperometric measurement of H2O2 is proposed to read out the potentiometric responses for the ISEs. The proposed amperometric signal readout based on H2O2 is carried out in a two compartment electrochemical cell configuration containing a detection cell and a sample cell, physically connected by a salt bridge. A glassy carbon (GC) electrode is placed in the detection cell to monitor the oxidation current of H2O2, and an ISE is placed in the sample cell to act as both the reference electrode and the potentiometric sensor for obtaining the ion activities. The oxidation of H2O2 is induced by a constant potential applied between the GC electrode and the ISE, and subsequently modulated by the potential change of the ISE in the presence of the primary ion. The proposed amperometric signal readout based on H2O2 shows the satisfied slope sensitivity and detection limit, which are better than or compared to those for the potentiometric responses for the ISEs. This work provides a general strategy for transforming the potential response of the ISEs into the amperometric readout, and is promising for detection of cations (eg., Ca2+) and anions (eg., NO3-) with high sensitivity and excellent selectivity

Matching Characteristics of Refrigerant and Operating Parameters in Large Temperature Variation Heat Pump

Characterizing the optimal operating parameters for a heat pump with a specific refrigerant is paramount, as it provides valuable guidance for refrigerant selection. The temperature mismatch between cold and hot fluids in the evaporator and condenser can lead to degraded thermal performance in heat pumps with large temperature variations. To address these two key issues, we selected several pure refrigerants with varying critical temperature levels for use in a large temperature variation heat pump configuration. The corresponding thermal performance was then investigated using the Ebsilon code under fixed temperature lift conditions as the operating temperature varied. It indicates that the maximum coefficient of performance (COP) is typically achieved when the deviation factors of temperature and pressure from their critical parameters fall within the ranges of 0.62~0.71 and 0.36~0.5, respectively. Our research recommends the binary refrigerant mixture of R152a/R1336mzz(z) (COP = 3.54) for the current operating conditions, as it significantly improves thermal performance compared to pure R1336mzz (z) (COP = 2.87) and R152a (COP = 3.01). Through research on the impact of the compositional ratio of R152a/R1336mzz(z) on the thermal performance of the heat pump, we found that that the optimal ratio of R1336mzz(z) component to R152a component is 0.5/0.5. This study offers valuable guidance for selecting the most suitable refrigerants for heat pumps in practical engineering design scenarios