Using Synoptic Classification and Trajectory Analysis to Assess Air Quality during the Winter Heating Period in rümqi, China

Synoptic patterns identified by an automated procedure employing principal- component analysis and a two-stage cluster analysis, and backward trajectory analysis clustered by the HYSPLIT4.9 model were used to examine air quality patterns over¨ Uru¨mqi, China, one of the most heavily polluted cities in the world. Six synoptic patterns representing different atmospheric circulation patterns and air-mass characteristics were classified during the winter heating periods from 2001 to 2008, and seven trajectory clusters representing different paths of air masses arriving at ürümqi were calculated during the winter heating periods from 2005 to 2008. Then air quality was evaluated using these two approaches, and significant variations were found across both synoptic patterns and trajectory clusters. The heaviest air-pollution episodes occurred when ürümqi was either in an extremely cold, strong anticyclone or at the front of a migrating cyclone. Both conditions were characterized by with light winds, cold, wet surface air, and relatively dry upper air. ürümqi was predominately influenced by air masses from the southwest and from local areas. Air pollution index （API） levels were highest for air masses originating from the southwest with a longer path or for the local area, because of transport from semi-desert/desert regions by strong winds and because of local heavy pollution emissions, respectively. The interactions between these two analytical approaches showed that poor diffusion conditions, together with local circulation, enhanced air pollution, besides, regional air-mass transport caused by strong winds contributed to serious air quality under relatively good diffusion conditions.

On the relationship between convection intensity of South China Sea summer monsoon and air-sea temperature difference in the tropical oceans

The annual, interannual and inter-decadal variability of convection intensity of South China Sea (SCS) summer monsoon and air-sea temperature difference in the tropical ocean is analyzed, and their relationship is discussed using two data sets of 48-a SODA (simple ocean data assimilation) and NCEP/NCAR. Analyses show that in wintertime Indian Ocean (WIO), springtime central tropical Pacific (SCTP) and summertime South China Sea-West Pacific (SSCSWP), air-sea temperature difference is significantly associated with the convection intensity of South China Sea summer monsoon. Correlation of the inter-decadal time scale (above 10 a) is higher and more stable. There is inter-decadal variability of correlation in scales less than 10 a and it is related with the air-sea temperature difference itself for corresponding waters. The inter-decadal variability of the convection intensity during the South China Sea summer monsoon is closely related to the inter-decadal variability of the general circulation of the atmosphere. Since the late period of the 1970s, in the lower troposphere, the cross-equatorial flow from the Southern Hemisphere has intensified. At the upper troposphere layer, the South Asian high and cross-equatorial flow from the Northern Hemisphere has intensified at the same time. Then the monsoon cell has also strengthened and resulted in the reinforcing of the convection of South China Sea summer monsoon.

Interannual variations of the air-sea carbon dioxide exchange in the different regions of the Pacific Ocean

Interannual variations of the air-sea CO2 exchange from 1965 to 2000 in the Pacific Ocean are studied with a Pacific Ocean model. Two numerical experiments are performed, including the control run that is forced by climatological monthly mean physical data and the climate-change run that is forced by interannually varying monthly mean physical data. Climatological monthly winds are used in both runs to calculate the coefficient of air-sea CO2 exchange. The analysis through the differences between the two runs shows that in the tropical Pacific the variation of export production induced by interannual variations of the physical fields is negatively correlated with that of the air-sea CO2 flux, while there is no correlation or a weak positive correlation in the subtropical North and South Pacific. It indicates that the variation of the physical fields can modulate the variation of the air-sea CO2 flux in converse ways in the tropical Pacific by changing the direct transport and biochemical process. Under the interannually varying monthly mean forcing, the simulated EOF 1 of the air-sea CO2 flux is basically consistent with that of sea surface temperature （SST） in the tropical Pacific, but contrary in the two subtropical Pacific Ocean. The correlation coefficient between the regionally integrated air-sea CO2 flux and area-mean SST shows that when the air-sea CO2 flux lags SST by about 5 months, the positive coefficient in the three regions is largest, indicating that in the tropical Pacific or on the longer time scale in the three regions, physical processes control the fiux-SST relationship.

Improved Ethanol Production from Xylose by Candida shehatae Induced by Dielectric Barrier Discharge Air Plasma

Xylose fermentation is essential for ethanol production from lignocellulosic biomass. Exposure of the xylose-fermenting yeast Candida shehatae （C. shehatae） CICC1766 to atmospheric pressure dielectric barrier discharge （DBD） air plasma yields a clone （designated as C81015） with stability, which exhibits a higher ethanol fermentation rate from xylose, giving a maximal enhancement in ethanol production of 36.2% compared to the control （untreated）. However, the biomass production of C81015 is lower than that of the control. Analysis of the NADH （nicotinamide adenine dinucleotide）- and NADPH （nicotinamide adenine dinucleotide phosphate）- linked xylose reductases and NAD＋-linked xylitol dehydrogenase indicates that their activities are enhanced by 34.1%, 61.5% and 66.3%, respectively, suggesting that the activities of these three enzymes are responsible for improving ethanol fermentation in C81015 with xylose as a substrate. The results of this study show that DBD air plasma could serve as a novel and effective means of generating microbial strains that can better use xylose for ethanol fermentation.

CO/Air称量法制备的不确定度评估

介绍了称量法制备CO/Air不确定度的评定过程;对称量数学模型的建立、称量过程、原料气体纯度分析及不确定度的评估方法进行了阐述;给出了CCQM-K84 CO/Air大气背景浓度的国际关键比对实验结果。

Studies of Several Systems with Air Electrode Electro-Synthesizing H_2O_2 on the Spot for Degr ading Aniline in Aqueous

A gas diffusion electrode (air electrode) with a high current efficiency of electro\|synthesizing H 2 O 2 using O 2 in air was prepared. The several systems with air electrode as cathode of ele ctro\|synthesizing H 2 O 2 on the reaction spot for degrading aniline in aqueous--electro\|Fenton system, photo\|excitation electro\|H 2 O 2 system and photo\|electro\|Fenton system, were developed. Th e rates of decomposition of H 2 O 2 and mineralization of anil ine were experimentally measured respectively under different conditions, and th e results indicated there has an excellent parallel relation between decompositi on rate of H 2 O 2 and mineralization rate of aniline. Especia lly, photo\|electro\|Fenton system, where H 2 O 2 is decompose d the fastest, is the best system of oxidizing and degrading organic toxicants. Compared photo\|electro\|Fenton system with photo\|Fenton system, important role is revealed in the interface of air electrode. In this paper, the mineralizatio n mechanism of aniline in the photo\|electro\|Fenton system was also discussed.

兆瓦级高速永磁同步电机偏心状态下电机性能及转子振动特性分析

在电机运行过程中,气隙偏心是一种常见的故障状态,会危害到电机的安全可靠运行,而该问题在大容量高速永磁同步电机中更为严重。因此,本文以一台兆瓦级高速永磁同步电动机为例,研究了气隙偏心对电机电磁性能以及其引发的不平衡磁拉力对转子振动特性的影响。首先,推导了静、动以及混合偏心状态下的不平衡磁拉力表达式。然后,建立了各偏心状态下的电机有限元模型,定量分析了不同偏心程度所引发的不平衡磁拉力变化情况。在此基础上,计算了电机转子系统的动力响应,详细讨论了各种偏心对转子系统轴心轨迹和电磁性能的影响。结果表明,不同偏心状态下不平衡磁拉力存在明显差异,在混合偏心时动偏心会削弱静偏心对转子振动的影响,偏心将增加气隙磁密的偶次谐波且增大转矩脉动。

汽车空调涡旋压缩机排气孔优化研究

针对汽车空调涡旋压缩机排气孔处气体流动变化产生的流动损失问题,对排气孔结构进行优化,以期降低流动损失并提高排气压力。通过三维动网格模型对不同排气孔结构的涡旋压缩机排气过程进行瞬态仿真,发现腰果形排气孔更大的截面积使其拥有更好的开启特性,可有效降低排气损失,提高排气稳定性。在对腰果形排气孔采取进一步扩压式优化后,发现其可以更加有效地降低排气速度并提高排气压力。

梳夹式红花采收装置集花机构优化与整机性能试验

针对研制的梳夹式红花采收装置存在采摘后的花丝掉落严重,导致花丝采集效率低的问题,提出一种新型的气吹-气吸组合式集花机构。该机构利用正压气流吹动粘附花丝脱离采摘头,同时结合梳夹装置前端安装的采摘头护罩,利用负压气流收集采摘后的花丝并防止花丝掉落。通过分析花丝在正压气流中受力情况,优化了集花机构的关键结构及工作参数。为验证整机性能,以含水率≥44.5%的新疆裕民红花为对象,对集花机构优化后的梳夹式红花采收装置进行了田间试验。试验结果表明:优化后的红花采收装置花丝采净率提升至81.74%,花丝掉落率降低至2.31%,相较于优化前采净率提高了4.47%,掉落率降低了0.31%,减少了花丝损失,整机性能得到提升,可为红花机械化高效低损采收提供参考。

脱盐海参气体射流冲击干燥特性及复水品质

为探索干燥条件对脱盐海参气体射流冲击干燥(air impingement drying,AID)特性的影响,提高海参干制品品质、缩短干燥时间,该文探讨AID温度(50、60、70℃)和气流速度(4、6、8 m/s)对脱盐海参干燥特性、有效水分扩散系数(Deff)、活化能(Ea)、干制品复水比和氨基酸含量的影响,用6种常见的干燥模型对干燥曲线进行拟合,并以热风干燥(hot air drying,HAD)为对比。结果表明,风速为6 m/s时,AID不同干燥温度下脱盐海参的干燥时间比HAD 60℃的干燥时间缩短6.67%~33.33%。温度为60℃时,风速对脱盐海参干燥时间影响不显著。不同干燥条件下,复水比无显著性差异。AID海参的氨基酸含量(45.91~47.54 g/100 g)随着温度的升高而升高。相同条件下,AID海参的氨基酸含量比HAD海参增加4.46%。AID脱盐海参的Deff最高为2.134×10⁃9,所需的活化能为16.38 kJ/mol。比较模型预测指标发现,Page模型具有较高的拟合度(R2>0.99),模型预测值和试验值误差仅为2.01%,可较准确地预测AID过程中脱盐海参的水分变化规律。

空压系统节能优化改造运行总结

针对空压系统的能耗高、压缩空气品质低等问题,经过数据分析和技术对比,采用离心式空压机、零气耗干燥机等新设备对空压系统进行优化节能改造,实现了卓越运营。

6G物理层原生AI技术

针对6G系统的空口AI化演进,需要对研究的路线、所受的限制条件、基础问题、技术趋势,以及期待的突破与改变做出客观和明确的判断,以便在不同层面和维度上获得理论与工程上的增益与突破,具体包括:引入AI的6G一体化、系统化构建,形成基于AI的新传输方案与新空口设计,考虑面向AI的生命周期管理与解决方案。在物理层原生AI技术方面,具体分析了零开销叠加导频设计、信道与无线环境语义通信,以及两项重点6G AI潜在技术方向。本研究可对未来6G系统AI化的技术推进和标准化提供有益参考。

综合性体育馆暖通空调设计的要点分析

通过对综合性体育馆空调负荷分析,赛时及赛后负荷组成,空调负荷分布特点指导冷热源选型及多种能源形式配置。分析比赛区空间气流组织形式及围绕二次回风的设计方法。比较了多种能源方案及气流组织,对冷热源的设计选型原则及BIM(Building Information Modeling,建筑信息模型)技术的应用进行总结。

利用旋转阀式蓄热氧化工艺实现减排温室气体技术探讨

煤矿瓦斯综合利用是煤矿甲烷减排的主要途径。由煤矿抽采泵站抽采出的瓦斯经过瓦斯掺混装置与空气(或乏风)进行均匀混配,混配后的浓度小于1.2%,经旋转阀式蓄热氧化装置进行无焰氧化,氧化后产生的热通过余热锅炉系统、发电系统,进行煤矿瓦斯综合利用。通过旋转阀式蓄热氧化工艺对煤矿瓦斯甲烷浓度不超过8%加以利用,助力煤矿实现温室气体减排。

某商用空调冷凝器隔声罩热环境模拟分析

上海市某餐饮店铺楼顶的空调室外机冷凝器在运行过程中会产生较高分贝噪声,超出噪声标准值18.54 dB。设计了一种能够满足该冷凝器降噪需求的复合隔声罩,考虑到加装此隔声罩之后,可能会导致冷凝器的散热不良,从而使得空调的使用效果变差。通过计算流体力学(CFD)仿真对冷凝器加装隔声罩前后的热环境进行模拟分析,得出添加隔声罩后冷凝器进风口、出风口温度分别升高了2.90、2.99℃,其热环境变化对设备影响在安全可控范围内的结论,从热环境的角度验证了该隔声罩的安全性与可行性。

江门文化中心空调通风系统设计

以江门文化中心为例,结合剧场环境要求及运行特点,对剧场空调冷热负荷、冷热源形式、观众厅和舞台的末端形式、气流组织、降噪隔振设计等进行了简要介绍。

某综合研发楼暖通空调系统的节能设计研究

随着建筑行业的蓬勃发展,暖通空调系统已成为建筑的重要组成部分。然而,高能耗一直是暖通空调系统亟须解决的重点问题,如何以节能的方式保证系统的稳定运行成为设计师的首要任务。为此,文章以某综合研发楼暖通空调系统设计为例,基于节能设计原则,从负荷的确定和优化变风量系统两个方面对暖通空调自动系统节能设计进行详细阐述,旨在提高暖通空调系统节能设计水平。

大型气候环境实验室空气处理系统方案探讨

目的探讨适用于大型气候环境实验室的空气处理系统方案。方法从大型气候环境实验室空气处理系统的功能出发,探讨循环风系统、新风系统和空气补偿系统方案,并对各系统的工作流程和优劣进行分析,在此基础上提出优化的集成空气处理系统方案。结果循环风系统采用串联风道比并联风道能更好地保证极限温湿度指标和均匀性指标,循环风系统与空气补偿系统集成方案优于两个个独立系统方案、具备可行性。结论该空气处理系统方案适用于大型气候环境实验室。

掺气减蚀研究的新方向

利用针式掺气流速仪测量掺气浓度场、流速场,气泡尺寸及其概率分布的研究成果表明,原型水流韦伯数高,形成微小气泡的能力比模型强,气泡上浮慢,接近底部的小尺寸气泡概率及掺气浓度比模型大.0.2mm或0.5mm以下的微小气泡可能在掺气减蚀中起着主要作用.完善掺气检测仪器,加强掺气水流中气泡尺寸及其概率分布的观测,比较不同气泡尺寸的掺气减蚀作用,建立多级气泡尺寸的掺气水流数学模型,是今后掺气减蚀研究的新方向.

U型和Y型通风采空区瓦斯分布数值模拟

运用Y型通风方式可解决传统U型通风难以解决的上隅角和回风巷瓦斯浓度超限问题。为了对比分析U型和Y型通风采空区瓦斯运移及分布规律,建立了U型通风和Y型通风采空区物理模型,运用Fluent软件对U型通风和Y型通风方式采空区漏风流场、漏风量(沿采空区边界风速分布)和瓦斯体积分数分布进行数值模拟。结果表明,Y型通风回采工作面采空区漏风流场与U型通风分布有较大差别。Y型通风时工作面端头0～30 m时漏风约占工作面漏风量的50%,且总漏风量较U型通风时多,可避免采空区高浓度瓦斯积聚。采用两进一回Y型通风可从根本上解决上隅角瓦斯积聚和回风巷瓦斯超限问题。