Crystal Structure of Benzene II at 25 Kilobars

Crystals of a high-pressure form of benzene (benzene 11) were grown in the diamond-anvil pressure cell at elevated temperature and pressure from the transition of solid I to solid II. X-ray precession data were obtained from a single-crystal in the high-pressure cell. At 21 degrees C and about 25 kilobars, benzene II crystallizes in the monoclinic system with a = 5.417 +/- 0.005 angstroms (S.D.), b = 5.376 +/- 0.019 angstroms, c = 7.532 +/- 0.007 angstroms, beta = 110.00 degrees +/- 0.08 degrees , space group P2(1)/ c, Pc= 1.26 grams per cubic centimeter. The crystal structure was solved by generating all possible molecular packing configurations and calculating structure factors, reliability factors, and packing energies for each configuration. This procedure produced a unique solution for the molecular packing of benzene II.     

大气颗粒物中有机污染物及自由基的检测

采用毛细管气相色谱－色质联手技术,分析了济南地区大气瓢尘及降尘中有机污染物的化学组成,共检测出１７０多种有机污染物,包括烃,酸,酞酸酯,醇,醛,酮,酚,酰胺,苯,萘及其衍生物,硝基化合物,联苯及其衍生物,三苯,茚,芘,芴菲,蒽以及苯并芘等多环芳烃化合物。     

苯·萘·菲在地下水含水层介质中的迁移规律研究

[目的]采用模拟渗流槽装置研究地下水中苯、萘、菲3种物质在含水层介质中的迁移规律。[方法]根据污染场地水文地质特征及污染特征,用地下水配制的苯、萘、菲3种污染物混合溶液作为试验供水水源,采取侧向补给的方式进行地下水在渗流槽的迁移试验。[结果]苯、萘、菲3种物质在含水层介质中的迁移速率大小顺序为苯萘菲;同时,4种含水层介质对污染组分的阻滞能力大小顺序为粉砂中砂粗砂砾砂;污染物在含水层中的迁移过程主要受吸附作用和微生物降解作用影响。各含水层介质对苯、萘、菲均有一定的吸附作用;在微生物降解苯、萘、菲的过程中,反应体系由好氧条件逐渐过渡为缺氧或者厌氧条件,电子受体由原来的O2变成了NO3-N和Fe(Ⅲ)。[结论]污染物在地下水中的迁移过程包括吸附作用和微生物降解作用。     

苏南某焦化厂场地土壤和地下水特征污染物分布规律研究

以苏南某焦化厂为研究对象,在对污染区域初步识别的基础上,采集了0～4.5 m深的22个土壤样品和2个地下水样品,利用GC/MS等检测了多环芳烃类、总石油烃、苯系物、重金属,总氰化物、挥发酚、硫化物的含量,并研究了其在不同功能区土壤和地下水中的特征分布。结果表明:(1)该焦化场土壤和地下水受到了不同程度的污染,其中炼焦炉周边、焦油和洗油储罐区、焦油和粗苯加工车间是污染最严重的区域;(2)土壤中主要超标污染物是多环芳烃、总氰化物、总石油烃、单环芳香烃、二苯呋喃、苯胺、硫化物、挥发酚和一些苯酚类化合物;(3)地下水重点污染区域粗苯车间受到总氰化物、苯胺、苯酚类、萘、总石油烃、单环芳香烃的严重污染,污水处理站区域地下水主要污染物包括总氰化物、萘、总石油烃、苯。     

石油污染场地地下水污染健康风险评估

阐述了对地下水进行健康风险评估的基本思路,并以东北某石油污染场地为例,基于场地水文地质调查、水化学分析,掌握了场地地下水的污染特征,根据地下水健康风险评估理论,对地下水中目标污染物给当地居民造成的人体健康风险进行评估,得到场地地下水污染物优先修复顺序及修复限值。结果表明,场地地下水致癌污染物优先修复顺序为铬、萘、苯、砷、镉;非致癌污染物优先修复顺序为砷、苯、铬。场地地下水修复限值,铬为0.76μg/L,萘为26.70μg/L,苯为13.00μg/L,砷为2.13μg/L,镉为0.10μg/L。     

焦化厂周围农业土壤中芳烃类物质的污染状况

通过实地采样 ,分析了炼焦地区的环境空气质量,同时用气相色谱法分析了焦化厂周围农业土壤中的多环芳烃类污染物的含量。结果表明:①焦炭生产地区TSP、SO2 和BaP日均最大值超过GB3095 -1996二级标准值的10、2.5和11.1倍。②焦化厂周围农业土壤受焦化厂气质污染物排放的影响 ,土壤中苯系物含量较高 ,其中苯的含量为6.148～11.96mg/kg,甲苯含量为1.56～5.238mg/kg,二甲苯含量为7.118～9.688mg/kg。焦化厂厂区植物叶片覆盖物中苯系物含量最高 ,含苯36.8mg/kg,甲苯10.22mg/kg ,二甲苯41.43mg/kg。     

萘降解菌的分离与鉴定

[目的]研究降解菌株对萘的降解能力,以期应用于被石油污染的土壤、水源等的生物修复。[方法]以多环芳香烃中含2个苯环结构的萘为材料,从襄樊市郊被石油污染的土壤中富集、筛选和分离能降解萘的微生物,通过生理生化试验,观察菌落及菌体形态。[结果]从土壤样和废油样中分离得到31个能以萘为唯一碳源生长的菌株,其中4个在平板上菌落较大,且具有不同的菌落特征,分别命名为L1、L8、L15和L19。其中,L1菌株对萘的降解能力最好,在初始萘浓度为100 mg/L的无机盐培养基中培养40 h,萘降解率为92%,且培养液中残留萘最少,仅有8 mg/L。菌L1菌株初步鉴定为微杆菌属。[结论]驯化条件是优势菌株筛选的重要制约因素,以萘为唯一碳源可驯化筛选出对萘具有较好降解效果的降解菌。     

Rapid, sensitive bioluminescent reporter technology for naphthalene exposure and biodegradation

A bioluminescent reporter plasmid for naphthalene catabolism (pUTK21) was developed by transposon (Tn4431) insertion of the lux gene cassette from Vibrio fischeri into a naphthalene catabolic plasmid in Pseudomonas fluorescens. The insertion site of the lux transposon was the nahG gene encoding for salicylate hydroxylase. Luciferasemediated light production from P. fluorescens strains harboring this plasmid was induced on exposure to naphthalene or the regulatory inducer metabolite, salicylate. In continuous culture, light induction was rapid (15 minutes) and was highly responsive to dynamic changes in naphthalene exposure. Strains harboring pUTK21 were responsive to aromatic hydrocarbon contamination in Manufactured Gas Plant soils and produced sufficient light to serve as biosensors of naphthalene exposure and reporters of naphthalene biodegradative activity. The robust and sensitive nature of the bioluminescent reporter technology suggests that new sensing methods can be developed for on-line process monitoring and control in complex environmental matrices.     

气相色谱法测定水中苯系物气液平衡条件研究

建立气液平衡-毛细管柱气相色谱法测定水中苯、甲苯、二甲苯的检测方法。通过确立该检测方法的条件试验,如色谱条件、气/液平衡条件等,进行气液平衡-毛细管柱气相色谱法的方法学试验。结果表明,3种组分在11 min内完成测定并具有较好的分离效果,苯的保留时间为2.6228 min,甲苯为3.9623 min,二甲苯为7.1101 min。该方法在2~10 mg/L浓度范围内可获得较好的直线方程,相关系数为0.960965~0.997645,精密度(RSD)为3.37%~11.36%,回收率为86.7%~112.0%。此方法操作简便、重现性好,提高了灵敏度,适用于检测水中苯系物的含量。     

Stratospheric meteorological conditions in the arctic polar vortex, 1991 to 1992

Stratospheric meteorological conditions during the Airborne Arctic Stratospheric Expedition II (AASE II) presented excellent observational opportunities from Bangor, Maine, because the polar vortex was located over southeastern Canada for significant periods during the 1991-1992 winter. Temperature analyses showed that nitric acid trihydrates (NAT temperatures below 195 k) should have formed over small regions in early December. The temperatures in the polar vortex warmed beyond NAT temperatures by late January (earlier than normal). Perturbed chemistry was found to be associated with these cold temperatures.     

The postspinel phase boundary in Mg2SiO4 determined by in situ X-ray diffraction

The phase boundary between spinel (gamma phase) and MgSiO3 perovskite + MgO periclase in Mg2SiO4 was determined by in situ x-ray measurements by a combination of the synchrotron radiation source (SPring-8) and a large multianvil high-pressure apparatus. The boundary was determined at temperatures between 1400 degrees to 1800 degreesC, demonstrating that the postspinel phase boundary has a negative Clapeyron slope as estimated by quench experiments and thermodynamic analyses. The boundary was located at 21.1 (+/-0.2) gigapascals, at 1600 degreesC, which is approximately 2 gigapascals lower than earlier estimates based on other high-pressure studies.     

Benzene Complexes with Copper(II)montmorillonite

Benzene formed a stable coinplex through its pi electrons to the copper ion in copper(II)montmorillonite. Copper(II)was the only exchangeable metal cation in montmorillonite to form a complex with benzene. Only those clay minerals whose charge arises in the octahedral layer produced the complex.     

Effects of Combined Instantaneous High-Pressure and Medium Temperature on the Retention of Total Vitamin C in Wax Gourd Juices

Based on the instantaneous high-pressure(IHP) produced by high-pressure single pole-cylinder pump, the effects of combining this pressure with medium temperature on the retention of total vitamin C(Vc) in wax gourd juices were investigated under 20-80 MPa, 35-58℃, pH 3.0-6.0 and processing time 0-8 min. Results showed that the loss of Vc increased with elevated processing temperatures (50 MPa, 4 min). When the temperature of raw juices was 35℃, the retention of total Vc was higher under 40-60 MPa than that under the pressure ＜ 40 MPa or ＞ 60 MPa, and it was up to 94% (4 min). The retention of total Vc decreases slowly within 6 min, but rapidly after 6 min. The pH can also influence the retention of total Vc, and this retention can come to a highest point at pH 6.0.     

Mammary cancer induction by 7,12-dimethylbenz(a)anthracene: relation to age

Mammary glands were transplanted from donors treated with 7,12-dimethylbenz(a)anthracene to untreated isologous recipients. Incidence of mammary tumors in mammary grafts from 56-day-old donors was significantly higher than that in grafts from 120-day-old donors, regardless of the age of the recipient hosts. Whent mammary glands were transplanted from untreated donors to isologous recipients that subsequently received 7,12-dimethyl-benz(a)anthracene, a similar difference in tumor incidence in the grafts was observed. In contrast to mammary glands of older females, mammary glands of young adult female rats are highly vulnerable to the carcinogenic effect of 7,12-dimethylbenz(a)anthracene.     

Controlled acceleration and inhibition of bergman cyclization by metal chlorides

The Bergman cyclization has been the subject of renewed interest with the discovery of naturally occurring enediyne-based antitumor agents that cleave DNA by means of an aromatic diradical. These natural substrates have a means to trigger this cycloaromatization process. Control of this reaction by substrate modification would allow aromatic diradicals to be generated selectively. In the studies presented here it is disclosed that the Bergman cyclization of 1,2-bis(diphenyl phosphinoethynyl) benzene was accelerated by a factor of >30,000 by the addition of palladium(II) chloride or platinum(II) chloride and was inhibited by the addition of mercury(II) chloride.     

In Situ Determination of the NiAs Phase of FeO at High Pressure and Temperature

In situ synchrotron x-ray diffraction measurements of FeO at high pressures and high temperatures revealed that the high-pressure phase of FeO has the NiAs structure (B8). The lattice parameters of this NiAs phase at 96 gigapascals and 800 kelvin are a = 2.574(2) angstroms and c = 5.172(4) angstroms (the number in parentheses is the error in the last digit). Metallic behavior of the high-pressure phase is consistent with a covalently and metallically bonded NiAs structure of FeO. Transition to the NiAs structure of FeO would enhance oxygen solubility in molten iron. This transition thus provides a physiochemical basis for the incorporation of oxygen into the Earth's core.     

Synchrotron X-ray Study of Iron at High Pressure and Temperature

X-ray synchrotron experiments with in situ laser heating of iron in a diamond-anvil cell show that the high-pressure epsilon phase, a hexagonal close-packed (hcp) structure, transforms to another phase (possibly a polytype double-layer hcp) at a pressure of about 38 gigapascals and at temperatures between 1200 and 1500 kelvin. This information has implications for the phase relations of iron in Earth's core.     

北京市东南郊再生水灌区地下水多环芳烃污染风险评估

为研究污染物随再生水进入地下环境后其迁移衰减情况及对地下水的潜在危害性,以Multi-cell模型为基础,结合污染物质量守恒、在水土中吸附再分配、生物降解等机理,针对地下水污染风险评估构建了计算污染物随水在土壤剖面的垂向迁移衰减一维模型,并以北京通州大兴再生水灌区为研究区域,以再生水中持久性有机污染物多环芳烃萘和菲为研究对象,根据当地钻孔资料及灌溉水水质、地下水水质资料,应用该模型进行试算.结果表明,经过多年连续灌溉后,通州大兴大部分地区进入潜水含水层的萘、菲浓度较低,整体污染风险较低,仅在通州区潞城镇等个别地区萘、菲浓度较高,应引起重视;由于大兴区整体包气带较厚,其污染风险低于通州区.土壤粘土层是萘、菲积累的主要层位,其吸附容量远大于细砂等粗颗粒介质,在土壤表层低环多环芳烃迁移性更强.应用这一模型,能够较为宏观地掌握通州大兴再生水灌区不同区域地下水中多环芳烃萘和菲的污染风险差异.     

含萘环环氧树脂的制备及其热性能研究

为了改善环氧树脂的耐热性能、吸水性及介电性能,以2,7-二羟基萘和环氧氯丙烷为原料合成含萘环结构的环氧树脂.通过原料配比、反应温度及时间等合成工艺参数的优化,得到含萘环环氧树脂合成的最佳工艺,并使用傅立叶变换红外光谱(FT-IR)、差示量热扫描仪(DSC)、热失重仪(TG)对环氧树脂的结构、玻璃化转变温度(Tg)及耐热...     

High-temperature synthesis of aromatic hydrocarbons from methane

Arenes of 1, 2, 3, 4 and more rings have been synthesized in a flow system by passing methane through silica gel at 1000 degrees C. Yields of 4.8 to 7.2 percent have been obtained per single pass. As determined by combined gas chromatography-mass spectrometry, the major compound synthesized that are of less than S rings are benzene, naphthalene, acenaphthylene, phenanthrene, fluoranthene, and pyrene. Under certain conditions ( presence of ammonia and water), small amounts of aliphatic hydrocarbons are also synthesized. Even-carbon-numbered hydrocarbons (aromatic as well as aliphatic) predominate, to the extent that about 97 percent of the total weight of the analyzed arenes have even numbers of carbon atoms.