排序方式: 共有12条查询结果,搜索用时 15 毫秒
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Li ZhaoBo Wang JianGuang Chen JingRong Lei WanHua Wang XueSong Zhang BaoWen 《中国科学:化学(英文版)》2010,53(9):1994-1999
pH-responsive 1O2 photosensitizing systems may serve as selective photodynamic therapy (PDT) agents by targeting the acidic interstitial fluid of many kinds of tumors. In this work, a natural and clinically used photosensitizer (Hypocrellin B, HB) and a pH indicator (Bromocresol Purple, BCP) were co-encapsulated in organically modified silica nanoparticles. BCP successfully regulated the 1O2 generation efficiency of HB through the “inner filter” effect, which shows much stronger 1O2 generation ability in an acidic than in a basic environment. In vitro experiments also demonstrated that HB-doped nanoparticles are effective in killing tumor cells by PDT.
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Based on atmospheric chemical kinetics, the rate constant of overall pseudo-first order oxidation re-moval of gaseous pollutants (Kpor,T) is proposed to characterize the atmospheric oxidation capacity in troposphere. Being a quantitative parameter, Kpor,T can be used to address the issues related to at-mospheric oxidation capacity. By applying this method, the regional oxidation capacity of the atmos-phere in Pearl River Delta (PRD) is numerically simulated based on CBM-IV chemical mechanism. Re-sults show the significant spatio-temporal variation of the atmospheric oxidation capacity in PRD. It is found that OH initiated oxidations, heterogeneous oxidation of SO2, and photolysis of aldehydes are the three most important oxidation processes influencing the atmospheric oxidation capacity in PRD. 相似文献
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Beijing,the capital of China,frequently suffers from the high levels of ozone in summer.A 3-D regional chemical transport model,the Comprehensive Air Quality Model with extensions(CAMx),has been used to simulate a heavy O3 pollution episode in Beijing during June 26―July 2,2000.Ozone Source Apportionment Technology(OSAT) and Geographic Ozone Assessment Technology(GOAT) were applied to quantify the contributions of the precursor emissions from different regions to O3 concentrations in Beijing,to identify the... 相似文献
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HaiChuan Chen JianPing Long Lijun Yang XueSong Wei KaMa Huang 《Physica B: Condensed Matter》2012,407(18):3705-3708
The lattice constants, band structure and dielectric properties of Ca1−xSrxTiO3 (0<x<1) (CSTO) have been studies by using the first-principles implemented with the GGA-PBEsol method. The calculation results shows that the lattice constants of CSTO obeys the Vegard model while the energy gap of CSTO shows a decreasing trend with the changing molar fraction x. The real and imaginary parts of the dielectric function and the static dielectric constant of the CSTO, optical permittivity and the static refractive index, are given to support the potential applications of the compounds in the future. 相似文献
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Models-3/CMAQ和CAMx对珠江三角洲臭氧污染模拟的比较分析 总被引:3,自引:0,他引:3
运用Models-3/CMAQ和CAMx两个区域空气质量模式同时对珠江三角洲2004年10月的臭氧污染进行模拟,利用监测网12个站点的观测数据对两个模式的臭氧模拟效果进行统计评估,并应用过程分析技术,量化各种大气物理、化学过程对臭氧浓度变化的影响,探讨两个模式结果偏差产生的主要原因.CMAQ与CAMx均能较好地模拟出珠江三角洲大多数站点的臭氧浓度水平和变化趋势,与监测值的相关系数分别为0.73,0.74,标准化平均偏差分别为-8.5%、8.8%、标准化平均误差分别为36.7%和37.9%;两个模式的模拟结果具有很高的相关性(相关系数R为0.92)和较为一致的空间分布,但CMAQ的臭氧模拟浓度总体上较CAMx的结果偏低约17%.两个模式对珠江三角洲不同地区、不同类型站点的模拟结果一致性不尽相同.在干沉降、化学反应参数、垂直输送等方面处理方法上的差异共同造成了两个模式对珠江口沿岸站点臭氧模拟结果上的差别;细网格边界浓度差异是造成上风向区域站点CAMx模拟浓度比CMAQ结果偏高的主要原因.CAMx有必要提供更多干沉降的算法供选择,改善光解速率等计算方法可能改善CMAQ臭氧模拟结果. 相似文献
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北京地区臭氧污染的来源分析 总被引:43,自引:1,他引:43
光化学烟雾污染是影响北京地区夏季空气质量的一个重要环境问题.利用区域空气质量模(CAMx)对2000年6月底至7月初发生在北京地区的臭氧污染过程进行模拟,运用臭氧源识别技术(OSAT)和地区臭氧评估技术(GOAT),量化了不同地区的污染源排放对北京市城近郊区臭氧污染的贡献,探讨了周边地区排放的臭氧贡献方式问题,分析了北京地区臭氧污染的化学机制特征.研究表明,北京地区臭氧污染分布存在显著差异,并且具有明显的区域性特征,定陵地区的超标臭氧主要受到城近郊区烟羽的严重影响(占55%),城近郊区则除了受到北京市的前体物排放影响外(占46%),来自天津市、河北省南部地区的贡献往往也占有重要份额;周边地区对北京市城近郊区的贡献中,直接输入的臭氧约占七层,其余部分以输入前体物的方式贡献臭氧;北京城近郊区的臭氧生成主要受挥发性有机物控制,而在远郊区县和农村地区臭氧生成对氮氧化物变得更为敏感.对北京地区臭氧污染的源排放控制,需要综合考虑各种臭氧来源和不同贡献方式的重要性,以及臭氧生成机制的变化规律. 相似文献
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Inactivation of <Emphasis Type="Italic">Shewanella putrefaciens</Emphasis> by Plasma Activated Water
Zhihua Qi Enqiang Tian Ying Song Eduard A. Sosnin Viktor S. Skakun Tingting Li Yang Xia Yao Zhao XueSong Lin Dongping Liu 《Plasma Chemistry and Plasma Processing》2018,38(5):1035-1050
Plasma activated water (PAW) generated by atmospheric-pressure air microplasma arrays is a solution containing a variety of reactive species. Here we investigate the effects of different applied voltage and water-activated time on bactericidal activities against Shewanella putrefaciens (S. putrefaciens). Our measurements showed that the sterilization efficiency of S. putrefaciens by PAW could be up to 2.0 Log Reduction. Scanning electron microscopy image and DNA concentration measurement showed that the S. putrefaciens cells were damaged and deformed due to the PAW treatment. The physicochemical properties of PAW treated by different applied voltage and water-activated time were evaluated, including pH value, initial PAW temperature, and the concentrations of plasma-activated species, such as H2O2, NO 3 ? , NO 2 ? , and O3. Analysis indicates that the sterilization efficiency of S. putrefaciens treated by PAW was mainly determined by H2O2 concentration and pH value of PAW. This study provides a basis for the PAW potential applications in the disinfection of rotten food. 相似文献
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The precise definition of polarization transform is proposed from the viewpoint of polarization domain transform for the first
time. The mathematical principle, characteristics and physical meanings of polarization transform are analyzed. Two typical
kinds of polarization transforms which are called unitary matrix polarization transform (UMPT) and diagonal matrix polarization
transform (DMPT) are put forward. The gain property and the change property of polarization state distance are presented in
detail. Thereby, the concept of serial polarization transform is proposed. A general polarization transform can be realized
by two steps: changing the location of polarization states in polarization domain by UMPT; and expanding or compressing the
density of polarization states by DMPT. The result is meaningful to many applications including polarization filtering, detection,
enhancement, anti-jamming, discrimination and so on.
Supported in part by the National Excellent PhD Dissertations Fund of China (Grant No. 08100101), the New Century Excellent
Talents Fund of China (Grant No. NCET-04-0997), the National Natural Science Foundation of China (Grant No. 60672033) and
the Excellent PhD Fund of National University of Defense Technology (Grant No. B070401) 相似文献