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Quantitative relationship between visibility and mass concentration of PM2.5 in Beijing

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Journal of Environmental Sciences 2006年第3期18卷 475-481页

作者： WANG Jing-li ZHANG Yuan-hang SHAO min liU Xu-lin zeng li-min CHENG Cong-lan XU Xiao-feng Institute of Urban Meteorology China Meteorological Administration Beijing 100089 China State Joint Key Laboratory of Environmental Simulation and Pollution Control College of Environmental Sciences Peking University Beijing 100871 China Beijing Meteorological Information and Network Center Beijing 100089 China

The pollution of particulate matter less than 2.5μm （PM2.5） is a serious environmental problem in Beijing. The annual average concentration of PM2.5 in 2001 from seasonal monitor results was more than 6 times that of the U,S, national ambient air quality standards proposed by U.S. EPA. The major contributors to mass of PM2.5 were organics, crustal elements and sulfate. The chemical composition of PM2.5 varied largely with season, but was similar at different monitor stations in the same season. The fine particles （PM2.5） cause atmospheric visibility deterioration through light extinction, The mass concentrations of PM2.5 were anti-correlated to the visibility, the best fits between atmospheric visibility and the mass concentrations of PM2.5 were somehow different： power in spring, exponential in summer, logarithmic in autumn, power or exponential in winter. As in each season the meteorological parameters such as air temperature and relative humidity change from day to day, probably the reason of above correlations between PM2.5 and visibility obtained at different seasons come from the differences in chemical compositions of PM2.5.

关键词： PM2.5 atmospheric urban aerosol air pollution meteorological factor visibility

Source profiles of particulate organic matters emitted from cereal straw burnings

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Journal of Environmental Sciences 2007年第2期19卷 167-175页

作者： ZHANG Yuan-xun SHAO min ZHANG Yuan-hang zeng li-min HE ling-yan ZHU Bin WEI Yong-jie ZHU Xian-lei State Key Joint Laboratory of Environmental Simulation and Pollution Control College of Environmental Sciences Peking University Beijing 100871 China Shenzhen Graduate School Peking University Shenzhen 518055 China

Cereal straw is one of the most abundant biomass burned in China but its contribution to fine particulates is not adequately understood. In this study, three main kinds of cereal straws were collected from five grain producing areas in China. Fine particulate matters （PMzs） from the cereal straws subjected to control burnings, both under smoldering and flaming status, were sampled by using a custom made dilution chamber and sampling system in the laboratory. Element carbon （EC） and organic carbon （OC） was analyzed. 141 compounds of organic matters were measured by gas chromatography-mass spectrum （GC-MS）. Source profiles of particulate organic matters emitted from cereal straw burnings were obtained. The results indicated that organic matters contribute a large fraction in fine particulate matters. Levoglucosan had the highest contributions with averagely 4.5% in mass of fine particulates and can be considered as the tracer of biomass burnings. Methyloxylated phenols from lignin degradation also had high concentrations in PM2.5, and contained approximately equal amounts of guaiacyl and syringyl compounds. 13-Sitostrol also made up relatively a large fraction of PMz5 compared with the other sterols （0.18%-0.63% of the total fine particle mass）. Normal alkanes, PAHs, fatty acids, as well as normal alkanols had relatively lower concentrations compared with the compounds mentioned above. Carbon preference index （CPI） of normal alkanes and alkanoic acids showed characteristics of biogenic fuel burnings. Burning status significantly influenced the formations of EC and PAHs. The differences between the emission profiles of straw and wood combustions were displayed by the fingerprint compounds, which may be used to identify the contributions between wood and straw burnings in source apportionment researches.

关键词： biomass burning cereal straw particulate organic matter source profile

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高原城市拉萨典型VOCs排放源成分谱特征

环境科学 2024年第4期45卷 2011-2018页

作者：郭淑政叶春翔林伟立陈熠曾立民尹晴晴刘雪莉民族地区生态环境国家民委重点实验室(中央民族大学) 北京100081 北京大学环境科学与工程学院北京100871

高海拔地区低的气压和含氧量会影响燃烧和溶剂挥发过程,进而影响挥发性有机物(VOCs)的排放特征.然而,人们对海拔3 000 m以上的燃烧源或挥发源的VOCs排放特征的认识有限.拉萨市正在经历快速的经济发展和城市化进程,VOCs排放源日趋复杂.... 详细信息

高海拔地区低的气压和含氧量会影响燃烧和溶剂挥发过程,进而影响挥发性有机物(VOCs)的排放特征.然而,人们对海拔3 000 m以上的燃烧源或挥发源的VOCs排放特征的认识有限.拉萨市正在经历快速的经济发展和城市化进程,VOCs排放源日趋复杂.采集拉萨市机动车尾气、汽油挥发、柴油挥发、液化石油气和燃香等排放源VOCs样品进行分析,研究成分谱特征,并与平原地区的相比较.发现液化石油气VOCs排放谱以丙烷和丁烷为主,与平原地区的一致;汽油挥发中1,2,4-三甲苯占比最高,而汽油车尾气中异戊烷、正丁烷和丙烷占比高,1,2,4-三甲苯占比较低,这不同于平原地区的结果;柴油挥发比汽油及汽油车排放具有更高占比的C7以上高碳化合物;柴油车排放中含氧挥发性有机物(OVOC)占比最高,而平原地区则是丙烯和C7以上烷烃占比高;燃香排放中OVOC占比最高,特征示踪物是乙腈,且有不容忽视的异戊二烯排放.从甲苯与苯的比值上看,汽油车及柴油车排放与平原地区的结果基本一致,但两地区柴油挥发和燃香排放则不同.从苯、甲苯和乙苯比例三元图上看,柴油挥发落在工业及溶剂排放区内,有别于平原地区的结果 .与其它城市一样,烯烃和芳香烃化合物也是高原城市中具有高反应活性VOCs组分,二者分别对臭氧和二次有机气溶胶的生成有重要的贡献.初步研究结果表明,高原城市地区不同VOCs源的组分特征与平原地区有所差异,需要进一步深入研究,以应对潜在的环境和健康风险.

关键词：挥发性有机物(VOCs) 源谱成分谱排放特征羟基消耗速率(L_(·OH)) 臭氧生成潜势(OFP)

Nested Saturated Control of Uncertain Complex Cascade Systems Using Mixed Saturation Levels

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IEEE/CAA Journal of Automatica Sinica 2024年第5期11卷 1163-1174页

作者： Meng li Zhigang zeng Wuhan National Laboratory for Optoelectronics Wuhan 430074 School of Artificial Intelligence and Automation Huazhong University of Science and TechnologyWuhan 430074China School of Artificial Intelligence and Automation Huazhong University of Science and TechnologyWuhan 430074 Key Laboratory of Image Processing and Intelligent Control of Education ministry of China Wuhan 430074China

This study addresses the problem of global asymptotic stability for uncertain complex cascade systems composed of multiple integrator systems and non-strict feedforward nonlinear systems. To tackle the complexity inherent in such structures, a novel nested saturated control design is proposed that incorporates both constant saturation levels and state-dependent saturation levels. Specifically, a modified differentiable saturation function is proposed to facilitate the saturation reduction analysis of the uncertain complex cascade systems under the presence of mixed saturation levels. In addition, the design of modified differentiable saturation function will help to construct a hierarchical global convergence strategy to improve the robustness of control design scheme. Through calculation of relevant inequalities, time derivative of boundary surface and simple Lyapunov function,saturation reduction analysis and convergence analysis are carried out, and then a set of explicit parameter conditions are provided to ensure global asymptotic stability in the closed-loop systems. Finally, a simplified system of the mechanical model is presented to validate the effectiveness of the proposed method.

关键词： method saturation differentiable

Gut virome:The next frontier in the treatment of necrotizing enterocolitis

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Chinese Medical Journal 2024年第5期137卷 562-564页

作者： Shuqin zeng li zeng Panyu Yang Qu Zheng Shaopu Wang Department of Pediatrics Key Laboratory of Birth Defects and Related Diseases of Women and Children(Sichuan University)Ministry of EducationWest China Second University HospitalSichuan UniversityChengduSichuan 610041China Sichuan Jinxin Xinan Women&Children Hospital ChengduSichuan 610000China

Necrotizing enterocolitis(NEC)is a devastating gastrointestinal disease over decades,which,however,remains the leading cause of morbidity and mortality in preterm infants.^([1])Although multiple factors,including gastrointestinal tract bacterial colonization,immaturity,and formula feeding,are reported to be involved in the pathogenesis of NEC,the precise mechanisms are not well understood.Owing to the advances in metagenomic sequencing,ample evidences have illustrated the presence of gut dysbacteriosis in infants with NEC,which is characterized by an elevated abundance of Proteobacteria,reduced abundance of Firmicutes phyla,and an overall decrease in bacterial diversity,providing novel insights into NEC progression.^([1,2])Additionally,the bacterial replication rates,particularly those of Enterobacteriaceae,rapidly increase two days prior to NEC diagnosis.^([2])

关键词： elevated frontier treatment

Quantum Neural Network for Quantum Neural Computing

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Research 2024年第1期2023卷 71-80页

作者： min-Gang Zhou Zhi-Ping liu Hua-Lei Yin Chen-Long li Tong-Kai Xu zeng-Bing Chen National Laboratory of Solid State Microstructures School of PhysicsCollaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China MatricTime Digital Technology Co.Ltd. Nanjing 211899China

Neural networks have achieved impressive breakthroughs in both industry and academia.How to effectively develop neural networks on quantum computing devices is a challenging open problem.Here,we propose a new quantum neural network model for quantum neural computing using(classically controlled)single-qubit operations and measurements on real-world quantum systems with naturally occurring environment-induced decoherence,which greatly reduces the difficulties of physical implementations.Our model circumvents the problem that the state-space size grows exponentially with the number of neurons,thereby greatly reducing memory requirements and allowing for fast optimization with traditional optimization algorithms.We benchmark our model for handwritten digit recognition and other nonlinear classification tasks.The results show that our model has an amazing nonlinear classification ability and robustness to noise.Furthermore,our model allows quantum computing to be applied in a wider context and inspires the earlier development of a quantum neural computer than standard quantum computers.

关键词： quantum thereby breakthrough

OsPDR20 is an ABCG metal transporter regulating cadmium accumulation in rice

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Journal of Environmental Sciences 2024年第2期136卷 21-34页

作者： He li Chao li Di Sun Zhi min Yang Department of Biochemistry and Molecular Biology College of Life SciencesNanjing Agricultural UniversityNanjing 210095China

Cadmium(Cd)is a non-essential toxic heavy metal,seriously posing high environmental risks to human health.Digging genetic resources relevant to functional genes is important for understanding the metal absorption and accumulation in crops and bioremediation of Cd-polluted environments.This study investigated a functionally uncharacterized ATP binding cassette transporter G family(ABCG)gene encoding a Pleiotropic Drug Resistance 20(PDR20)type metal transporter which is localized to the plasma membrane of rice.OsPDR20 was transcriptionally expressed in almost all tissues and organs in lifespan and was strongly induced in roots and shoots of young rice under Cd stress.Ectopic expression of OsPDR20 in a yeast mutant ycf1 sensitive to Cd conferred cellular tolerance with less Cd accumulation.Knockdown of OsPDR20 by RNA interference(RNAi)moderately attenuated root/shoot elongation and biomass,with reduced chlorophylls in rice grown under hydroponic medium with 2 and 10μmol/L Cd,but led to more Cd accumulation.A field trial of rice grown in a realistic Cd-contaminated soil(0.40 mg/kg)showed that RNAi plants growth and development were also compromised compared to wild-type(WT),with smaller panicles and lower spikelet fertility but little effect on yield of grains.However,OsPDR20 suppression resulted in unexpectedly higher levels of Cd accumulation in rice straw including lower leaves and culm and grain.These results suggest that OsPDR20 is actively involved in Cd accumulation and homeostasis in rice crops.The increased Cd accumulation in the RNAi plants has the potential application in phytoremediation of Cd-polluted wetland soils.

关键词： Rice ABCG transporter Cadmium accumulation Phytoremediation

Stable graphene oxide-based lyotropic liquid crystals for interfacial lubrication

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Friction 2024年第5期12卷 954-967页

作者： Yumei GUO Hanglin li Jiusheng li Xiangqiong zeng Laboratory for Advanced Lubricating Materials Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai201210China University of Chinese Academy of Sciences Beijing100049China

Lyotropic liquid crystals have lubricating properties due to their ordered assembly and fluidity,whose mesogens are often characterized by amphiphilic properties.Despite the attention that graphene oxide(GO)has been studied as a novel amphiphilic lyotropic mesogen this decade,and GO applied as a lubrication additive has been demonstrated in both oil and water-based systems,little research reveals the interfacial lubrication of GO liquid crystals yet.This work reports that GO aqueous dispersion can form lyotropic liquid crystals above a specific critical concentration of 5.00 mg/mL,providing a form of stable water-based lubricant,which can keep stable for several months and can reduce friction by 37.3%and wear by 25.24%.The liquid crystal phase was verified by polarizing microscope and synchrotron radiation small-angle X-ray scattering,and its rheological properties and viscoelasticity were studied by interfacial rheometer.The formation of lyotropic liquid crystals can enhance the stability of GO aqueous dispersions at high density,simultaneously ensuring friction decrease and anti-wear effect.It is attributed to the stable nematic network by the ordered GO sheets.The ordered assembly structure bears vertical shear force,therefore,reducing the wear.It is also assumed that the wide lateral size of graphene oxide promotes the nematic phase thus smoothes the graphene oxide film composed spontaneously under the coincidence of lamellar liquid crystal and 2D layered material.Through this work,the interlayer lubrication of GO was optimized,and the problem of GO dispersion sedimentation was solved by self-assembly.The range of interfacial lubrication of GO aqueous dispersion has been expanded and the synergistic effect is conducive to the environmentally friendly lubricants.

关键词： lyotropic liquid crystal graphene oxide aqueous lubrication tribological behavior

TRPC6 Knockout Alleviates Renal Fibrosis through PI3K/AKT/GSK3B Pathway

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Current Medical Science 2024年第3期44卷 589-602页

作者： An-bang SUN Fang-hua li lin ZHU Xi-xi zeng min ZHU Qing-hua LEI Yan-hong liAO Department of Anatomy School of Basic MedicineTongji Medical CollegeHuazhong University of Science and TechnologyWuhan430030China Department of Transfusion Medicine Wuhan Hospital of Traditional Chinese and Western MedicineTongji Medical CollegeHuazhong University of Science and TechnologyWuhan430030China Department of Nephrology The First Affiliated Hospital of Zhengzhou UniversityZhengzhou450052China Department of Thoracic Surgery Tongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan430030China National Basic Medical Teaching Demonstration Center Tongji Medical CollegeHuazhong University of Science and TechnologyWuhan430030China Key Laboratory of Neurological Diseases of ministry of Education Tongji Medical CollegeHuazhong University of Science and TechnologyWuhan430030China

Objective Renal fibrosis is the ultimate pathway of various forms of acute and chronic kidney damage.Notably,the knockout of transient receptor potential channel 6(TRPC6)has shown promise in alleviating renal fibrosis.However,the regulatory impact of TRPC6 on renal fibrosis remains unclear.Methods In vivo,TRPC6 knockout(TRPC6−/−)mice and age-matched 129 SvEv(WT)mice underwent unilateral renal ischemia-reperfusion(uIR)injury surgery on the left renal pedicle or sham operation.Kidneys and serum were collected on days 7,14,21,and 28 after euthanasia.In vitro,primary tubular epithelial cells(PTECs)were isolated from TRPC6−/−and WT mice,followed by treatment with transforming growth factorβ1(TGFβ1)for 72 h.The anti-fibrotic effect of TRPC6−/−and the underlying mechanisms were assessed through hematoxylin-eosin staining,Masson staining,immunostaining,qRT-PCR,and Western blotting.Results Increased TRPC6 expression was observed in uIR mice and PTECs treated with TGFβ1.TRPC6−/−alleviated renal fibrosis by reducing the expression of fibrotic markers(Col-1,α-SMA,and vimentin),as well as decreasing the apoptosis and inflammation of PTECs during fibrotic progression both in vivo and in vitro.Additionally,we found that the phosphatidylinositol 3-kinase(PI3K)/protein kinase B(AKT)/glycogen synthase kinase 3 beta(GSK3β)signaling pathway,a pivotal player in renal fibrosis,was down-regulated following TRPC6 deletion.Conclusion These results suggest that the ablation of TRPC6 may mitigate renal fibrosis by inhibiting the apoptosis and inflammation of PTECs through down-regulation of the PI3K/AKT/GSK3βpathway.Targeting TRPC6 could be a novel therapeutic strategy for preventing chronic kidney disease.

关键词： transient receptor potential channel 6 ischemia-reperfusion injury renal fibrosis renal tubular epithelial cells