对翼龙的几点新解释

在概述翼龙研究状况基础上根据所掌握资料提出：①翼龙发达的胸骨和肩带说明不但能滑翔而且能进行相当强度的动力飞行。②翼龙身覆皮毛显示其具有温血生理特征，其习性在某种程度上可能与鸟类相似，如筑巢、产卵、孵卵及哺雏等。③一些类似水禽的翼龙在足趾间可能长有划水用的蹼。     

三元氧化体系中协同效应与羟基自由基产率关系的研究

本研究构建了VUV-US-O_3三元氧化体系,以水杨酸(SA)为分子探针,采用高效液相色谱和荧光检测器联用测定分析三元氧化体系的·OH产率.结果表明,各氧化体系的氧化能力排序为VUV/US/O_3VUV/O_3US/O_3VUV/USO_3VUVUS,120 min内对应的SA去除率分别为96.27%、83.57%、74.80%、68.88%、50.67%、36.06%、8.60%,组合体系显示出了明显的协同效应;VUV/O_3、VUV/US和US/O_3中检测出羟基化产物的最高浓度分别为12.32、7.51、4.47μmol·L~(-1),较VUV、US、O_3单独氧化产生的羟基化产物浓度(分别为5.22、0.34、3.61μmol·L~(-1))更高,推测各二元氧化体系中的协同效应主要是由·OH产率增加而引起;将US加入VUV/O_3体系中构成VUV/US/O_3三元氧化体系后,可加速O_3溶解并提高·OH最高产率至22.24μmol·L~(-1),使VUV/US/O_3氧化能力进一步提高.     

Catalytic determination of ultratrace chromium based on gallocyanine‐hydrogen peroxide indicator reaction

A highly sensitive catalytic procedure for the determination of ultratrace chromium(VI) was developed based on its catalytic effect on the oxidation of gallocyanine by hydrogen peroxide in hexamine‐hydrochloric acid buffer solution. The reaction was followed spectrophotometrically by measuring the rate of change in the absorbance at 620 nm. The apparent active energy of the catalytic reaction is 6.84 kJ . mol^‐1. The calibration graph is linear for 0–150 ng.ml^‐1, and the detection limit is 0.8 ng.ml^‐1. Most foreign ions have no interfering effect on the determination of chromium(VI) except for Al³⁺, Cu²⁺, Fe³⁺and Fe²⁺. The interference of Al³⁺ is eliminated by masking with F^‐, and those of Cu²⁺, Fe³⁺ and Fe²⁺ are eliminated by adding appropriate amount of EDTA. The present procedure had been used for the determination of trace chromium(VI) in lake water, mine water and electroplating wastewater, and the results were satisfactory.     

选择性去除香烟烟气中亚硝胺的研究

沸石具有选择性吸附和催化去除亚硝胺的功能.使用沸石添加剂和/或微波辐射预处理,可将香烟侧流烟气中致癌性物质亚硝胺的含量降低约50%,主流烟气中降低60-90%,能有效地减轻吸烟对于环境的污染.     

Concentrations, transport, fate, and releases of polybrominated diphenyl ethers in sewage treatment plants in the Pearl River Delta, South China

Wastewater has proved to be a significant source of polybrominated diphenyl ethers (PBDEs) in the environment. Seventeen congeners from tri- to deca-BDEs were determined to characterize the occurrence, fate, and transport of PBDEs in two sewage treatment plants in the Pearl River Delta, South China. The PBDE concentrations varied substantially from 13.3 to 2496.4 ng L(-1) in the raw wastewater, depending on the wastewater types and contents of the suspended particulate matter (SPM). The concentrations declined to 0.9 to 4.4 ng L(-1) in the treated effluent and were closely associated with SPM contents. BDE-209 was the predominant congener in the wastewater and sewage sludge. Most of PBDEs might have ended up in the sewage sludge, with <4.7% being discharged with the treated effluent. The results revealed that PBDEs were not significantly degraded by biological treatment and chlorination in the STPs. An annual release of PBDEs was estimated at 2280 kg/year through wastewater from the Pearl River Delta.     

Historical and projected emissions of major halocarbons in China

The halocarbons studied here are chemicals controlled in the 1987 Montreal Protocol on Substances that Deplete the Ozone Layer and its Amendments, which have both high ozone depleting potentials (ODPs) and high global warming potentials (GWPs). These halocarbons are mainly used for refrigeration, air-conditioning, foam blowing, tobacco expansion, aerosol propulsion, solvent cleaning, and fire fighting. China ratified the Montreal Protocol in 1991 and has been implementing the phase-out of halocarbons since then. In this paper, the emissions of halocarbons from China were estimated for 1995–2024 based on the historical consumption, the country program for complying with the Montreal Protocol, and the sector plans for phasing out halocarbons. The results show that China's compliance with the Montreal Protocol contributes greatly to both ozone protection and climate protection.     

Sensitivity analysis of TOPSIS method in water quality assessment II: sensitivity to the index input data

This is the second part of the study on sensitivity analysis of the technique for order preference by similarity to ideal solution (TOPSIS) method in water quality assessment. In the present study, the sensitivity of the TOPSIS method to the index input data was investigated. The sensitivity was first theoretically analyzed under two major assumptions. One assumption was that one index or more of the samples were perturbed with the same ratio while other indices kept unchanged. The other one was that all indices of a given sample were changed simultaneously with the same ratio, while the indices of other samples were unchanged. Furthermore, a case study under assumption 2 was also carried out in this paper. When the same indices of different water samples are changed simultaneously with the same variation ratio, the final water quality assessment results will not be influenced at all. When the input data of all indices of a given sample are perturbed with the same variation ratio, the assessment values of all samples will be influenced theoretically. However, the case study shows that only the perturbed sample is sensitive to the variation, and a simple linear equation representing the relation between the closeness coefficient (CC) values of the perturbed sample and variation ratios can be derived under the assumption 2. This linear equation can be used for determining the sample orders under various variation ratios.     

TG-DSC and FTIR study on pyrolysis of irradiation cross-linked polyethylene

Irradiation cross-linked polyethylene (PEX) and irradiation cross-linked polyethylene with carbon black filler (CB-PEX) are two types of scraps, generated in electric cable production. Their pyrolysis is studied in this work using instrumental TG\DSC\FTIR techniques and kinetic analysis. The experiments are performed at a constant heating rate of 10 °C/min in nitrogen flow at atmospheric pressure. It is found that the main pyrolysis stage is in the temperature range of 395–503 °C for PEX, and in range of 408–515 °C for CB-PEX. In the main pyrolysis stage, CB-PEX requires more external heat than PEX does. Olefins are the major products of pyrolysis for both materials, but they are quite different in their composition and molecular weight distribution. PEX can be converted almost quantitatively into volatile compounds. CB-PEX has a stronger coking tendency, as well as a larger residue composed of carbon black.     

Emissions behavior and distribution of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) from cement kilns in China

The production of cement in China is accompanied by various emissions, such as fine particulate matter, heavy metals, nitrogen oxides, sulfur oxides, carbon dioxide…. Moreover, cement kiln presents a potential health risk to its surroundings, linking to emissions of persistent organic pollutants (POPs), such as polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), in brief dioxins. Flue gas samples were collected from five typical cement kilns during twelve runs and were used to evaluate the levels and distribution of PCDD/Fs in the emissions from cement kilns. The PCDD/Fs concentrations (136 congeners) and I-TEQ values ranged from 2.3 to >40 ng/m³ and 9.3?～?90.8?×?10^?3 ng I-TEQ/m³, respectively, which were lower than the emission standard in China (0.1 ng I-TEQ/m³). In weight units, the dominant congeners were OCDD, 1,2,3,4,6,7,8-HpCDF, and OCDF; 2,3,4,7,8-PeCDF is the largest contributor (36–66 %) to the total I-TEQ value of twelve runs. HxCDF and TCDF were the first two most abundant homologue groups (12–85 and 4–52 %), and the homologue concentration decreased with rising chlorine number for PCDDs. In addition, there was no marked difference in homologue profiles when solid wastes (refuse-derived fuel and municipal solid waste) and hazardous wastes (DDT and POPs) were combusted as supplemental fuels. The use of various supplemental fuels had no obvious effect on the fingerprint of PCDD/F homologues. Moreover, there was no significant difference in levels of PCDD/Fs emission due to the diversity of production capacity, which were consistent with reported previously. Air pollution control device had effect on the homologue profiles, and cement system with electrostatic precipitators (ESP) had more fractions of octachloro congeners to the total.