Short-chain chlorinated paraffins(SCCPs) are produced in high volume and have the high potential to pose a threat to human health. However, little information is available for SCCP contamination in human blood/plasma/...Short-chain chlorinated paraffins(SCCPs) are produced in high volume and have the high potential to pose a threat to human health. However, little information is available for SCCP contamination in human blood/plasma/serum, mainly due to the difficulty of sample preparation and quantitative analysis. A method using high resolution gas chromatography coupled with electron capture negative ionization low resolution mass spectrometry(HRGC–ECNI/LRMS) was developed and validated to measure SCCPs in human plasma. The pretreatment process included protein denaturation and lipid elimination, liquid–liquid extraction with a mixture of n-hexane/dichloromethane(1:1, V/V), and cleanup on a multilayer silica column. The blank controls, including procedural blank, vacuum blood collection tube blank, and instrumental blank, were the most pivotal points for the reliable analysis of SCCPs. The average value of procedural blanks was 9.0 ng/g; and the method detection limit(MDL), calculated as the sum of the average procedural blank value and 3 times of the standard deviation of the procedural blanks, was 12.6 ng/g plasma. The validated method was applied to measure the concentrations of the total SCCPs(∑ SCCPs) in50 plasma samples from a general population. The measured plasma concentrations of ∑SCCPs ranged from <MDL to 203 ng/g wet weight(ww), with an average value of 32.0 ng/g ww.The relative abundance profiles of SCCPs in plasma samples were dominated by C10- and C11-CP congener groups centered on Cl6–7. The developed method can be used for the comprehensive and large-scale investigation of SCCP levels in human plasma.展开更多
The increasing production and usage of chlorinated paraffins(CPs) correspondently increase the amount of CPs that experience thermal processes. Our previous study revealed that a significant amount of medium-chain chl...The increasing production and usage of chlorinated paraffins(CPs) correspondently increase the amount of CPs that experience thermal processes. Our previous study revealed that a significant amount of medium-chain chlorinated paraffins(MCCPs), short-chain chlorinated paraffins(SCCPs) as well as aromatic and chlorinated polycyclic aromatic hydrocarbons(Cl-PAHs) were formed synergistically during the thermal decomposition of CP-52(a class of CP products).However, the transformation mechanisms of CP-52 to these compounds are still not very clear.This article presents a mechanistic analysis on the decomposition of CP-52 experimentally and theoretically. It was found that CP-52 initially undergoes dehydrochlorination and carbon chain cleavage and it transformed into chlorinated and unsaturated hydrocarbons. Cyclization and aromatization were the most accessible pathways at low temperatures(200–400°C), both of which produce mostly aromatic hydrocarbons. As the temperature exceeds 400°C, the hydrocarbons could decompose into small molecules, and the subsequent radical-induced reactions become the predominant pathways, leading to the formation of Cl-PAHs. The decomposition of CP-52 was investigated by using density functional theory and calculations demonstrating the feasibility and rationality of PCB and PCN formation from chlorobenzene. The results improve the understanding of the transformation processes from CP-52 to SCCPs and Cl-PAHs as well as provide data for reducing their emissions during thermal-related processes.展开更多
Chlorinated paraffins（SCCPs） are widely used worldwide, and they can be released into the environment during their production, transport, usage and disposal, which pose potential risks for human health. In this work...Chlorinated paraffins（SCCPs） are widely used worldwide, and they can be released into the environment during their production, transport, usage and disposal, which pose potential risks for human health. In this work, an efficient, reliable and rapid pretreatment method based on matrix solid-phase dispersion（MSPD） was developed for the analysis of short-chain CPs（SCCPs） in human placenta by gas chromatograph-electron capture negative ion low-resolution mass spectrometry（GC-ECNI-LRMS） and gas chromatography–quadrupole time-of-flight mass spectrometry（GC–QTOF-HRMS）. The MSPD-relevant parameters including dispersing sorbent,sample-to-sorbent mass ratio, and elution solvent were optimized using the orthogonal test.Silica gel was found to be the optimal dispersing sorbent among the selected matrices. Under the optimal conditions, 44% acidic silica gel can be used as the co-sorbent to remove lipid and eluted by the mixture of hexane and dichloromethane（7：3, V/V）. The spiked recoveries of the optimized method were 77.4% and 91.4% for analyzing SCCPs in human placenta by GC-ECNI-LRMS and GC–QTOF-HRMS, and the corresponding relative standard deviations were10.2% and 5.6%, respectively. The method detection limit for the total SCCPs was 36.8 ng/g（dry weight, dw） and 19.2 ng/g（dw） as measured by GC-ECNI-LRMS and GC–QTOF-HRMS,respectively. The concentrations of SCCPs in four human placentas were in the range of展开更多
Pristine alpine regions are ideal regions for investigating the long-range atmospheric transport and cold trapping effects of short chain chlorinated paraffins(SCCPs).The concentrations and alpine condensation of SCCP...Pristine alpine regions are ideal regions for investigating the long-range atmospheric transport and cold trapping effects of short chain chlorinated paraffins(SCCPs).The concentrations and alpine condensation of SCCPs were investigated in lichen samples collected from the southeastern Tibetan Plateau.The concentrations of SCCPs ranged from 3098 to 6999 ng/g lipid weight(lw)and appeared to have an increasing trend with altitude.For congeners,C10 dominated among all the congener groups.The different environmental behavior for different congener groups was closely related to their octanol-air partition coefficient(Koa).C10 congeners showed an increasing trend with altitude,whereas C13 congeners were negatively correlated with altitude.Volumetric bioconcentration factors(BCF)of SCCPs reached 8.71 in lichens,which were higher than other semivolatile organic compounds(SVOCs)such as organochlorine pesticides(OCPs),polybrominated diphenyl ethers(PBDEs),polychlorinated biphenyls(PCBs),and hexabromocyclododecane(HBCD).These results suggested that SCCPs were prone to accumulate in the lichen from the air and provided evidence for the role of lichens as a suitable atmospheric indicator in the Tibetan Plateau.展开更多
Short chain chlorinated paraffins （SCCPs） are not only research focus of environmental issues but also interesting model mol- ecules for organic chemistry which exhibit diverse conformation preference and intramolec...Short chain chlorinated paraffins （SCCPs） are not only research focus of environmental issues but also interesting model mol- ecules for organic chemistry which exhibit diverse conformation preference and intramolecular noncovalent interactions （NCIs）. A systematic study was conducted to reveal the conlk）rmation preference and the related intramolecular NCIs in two C^-isomers of SCCPs, 5,5,6,6-tetrachlorodecane and 4,4,6,6-1etrachlorodecane. The overall conformation profile was deter- mined on the basis of relative energies calculated at the MP2/6-311＋＋G（d,p） level with the geometries optimized by B3LYP/6-31 l＋＋G（d,p） method. Then, quantum theory of atoms in molecules （QTAIM） has been adopted to identify the NCls in the selected conformers of the model molecules at both B31~YP/6-31 l＋＋G（d,p） and M06-2X/aug-cc-pvdz level. Different chlorine substitution modes result in varied conformation preference. No obvious gauche effect can be observed tk）r the SCCPs with chlorination on adjacent carbon atoms. The most stable conformer of 5,5,6,6-tetrachlorodecane （tTt） has its three dihedral angles in the T configuration, and there is no intramolecular N（3s found in this molecule. On the contrary, the chlorination on interval carbon atoms favors the adoption of gauche configmation for the H C C CI axis. Not only inlramolecular H-..CI contacts but also H---H interactions have been identified as driving forces to compensate the instability from steric crowding ot the gauche configuration. The gggg and g＇g＇g＇g＇ conformers are the most popular ones, while the populations of tggg and tg＇g＇g＇ conformer are second to those of the gggg and g＇g＇g＇g＇ conformers. Meanwhile, the M06-2X method with large basis sets is preferred for identification of subtle intramolecular NCIs in large molecules like SCCPs.展开更多
Chlorinated paraffins(CPs)are produced in large amounts and used worldwide.Dietary intake is the primary pathway for the exposure of pets to CPs,but limited information is available concerning the potential contaminat...Chlorinated paraffins(CPs)are produced in large amounts and used worldwide.Dietary intake is the primary pathway for the exposure of pets to CPs,but limited information is available concerning the potential contamination of pet food by CPs.In the present study,the concentrations and congener group profiles of short-chain CPs(SCCPs)and medium-chain CPs(MCCPs)were assessed in 35 imported commercial dry cat and dog foods collected in China,and the estimated daily intakes of SCCPs and MCCPs for cats and dogs through the consumption of such foods was calculated.The concentrations of SCCPs and MCCPs in the cat and dog foods were determined to be in the ranges of 108e45,300 ng/g(median:1340 ng/g)and 3.8e52,700 ng/g(median:11 ng/g),respectively.The predominant congener groups were C10Cl6 for SCCPs and C14Cl7-8 for MCCPs.The high levels of CPs found in certain pet foods suggest the potential for adverse health effects.展开更多
Oil-gas two phase wax deposition is a fairly common and open-ended question in flow assurance of multiphase transportation pipelines.This paper investigated the two main aspects of oil-gas two phase wax deposition lay...Oil-gas two phase wax deposition is a fairly common and open-ended question in flow assurance of multiphase transportation pipelines.This paper investigated the two main aspects of oil-gas two phase wax deposition layer:apparent thickness and crystal structure characteristics.A typical highly paraffinic oil in Bohai Sea,China,was used as the experimental material to investigate the wax deposition thickness in oil-gas two phase under the influence of different oil temperatures,superficial gas/liquid phase velocities and gas-oil ratios by using multiphase flow loop experimental device.Just as in the classical theory of wax molecular diffusion,it showed that wax deposition thickness of oil-gas two phase increased with increasing oil temperature.Analysis of the impact of different superficial phase velocities found that the actual liquid flow heat transfer and shear stripping was the gas phase dominant mechanisms determining wax deposit thickness.In addition,the crystal structure of the wax deposition layer was characterized with the help of small-angle X-ray scattering(SAXS)for different circumferential positions,flow rates and gas-oil ratios.The bottom deposition layer had a complex crystal structure and high hardness,which were subject to change over flow rate variations.Furthermore,the SAXS results provided evidence that the indirect effect of the actual liquid velocity modified by the gas phase was the main mechanism.Our study of the effect of gas phase on the wax deposition of oil-gas two phase will help shed light onto the mechanism by which this important process occurs.Our findings address a very urgent need in the field of wax deposition of highly paraffinic oil to understand the flow security of oilgas two phase that occurs easily in multiphase field pipelines.展开更多
The novel calcium-silicate-hydrate(C-S-H)/paraffin composite phase change materials were synthesized using a discontinuous two-step nucleation method.Initially,the C-S-H precursor is separated and dried,followed by im...The novel calcium-silicate-hydrate(C-S-H)/paraffin composite phase change materials were synthesized using a discontinuous two-step nucleation method.Initially,the C-S-H precursor is separated and dried,followed by immersion in an aqueous environment to transform it into C-S-H.This two-step nucleation approach results in C-S-H with a specific surface area of 497.2 m^(2)/g,achieved by preventing C-S-H foil overlapping and refining its pore structure.When impregnated with paraffin,the novel C-S-H/paraffin composite exhibits superior thermal properties,such as a higher potential heat value of 148.3 J/g and an encapsulation efficiency of 81.6%,outperforming conventional C-S-H.Moreover,the composite material demonstrates excellent cyclic performance,indicating its potential for building thermal storage compared to other paraffin-based composites.Compared with the conventional method,this simple technology,which only adds conversion and centrifugation steps,does not negatively impact preparation costs,the environment,and resource consumption.This study provides valuable theoretical insights for designing thermal storage concrete materials and advancing building heat management.展开更多
SiC aerogel presents several advantageous features like lightweight and high temperature resistance when applied as microwave absorbing material.In this paper,SiC aerogel was prepared eventually followed by the sol-ge...SiC aerogel presents several advantageous features like lightweight and high temperature resistance when applied as microwave absorbing material.In this paper,SiC aerogel was prepared eventually followed by the sol-gel and carbonization reduction process.The results showed that the effective electromagnetic microwave absorption capacity of SiC aerogel was highly increased after being pyrolyzed at 1500℃,which presented a minimum reflection loss value of-57.80 dB at 3.10 mm and 9.86 GHz.Besides,the electromagnetic parameters of SiC aerogel with different paraffin ratios were discussed as well as the varying electromagnetic microwave absorption performances.The minimum reflection loss value first rose then fell as the SiC/paraffin ratio increased,which demonstrated the importance of SiC content.This study establishes the theoretical foundation for the subsequent functional application of SiC aerogel.展开更多
The production of deep well-shaped WC-Co cemented carbide blocks via industrial powder pressing remains a challenging technical problem,primarily due to the unsuitability of the forming agent.The forming agent paraffi...The production of deep well-shaped WC-Co cemented carbide blocks via industrial powder pressing remains a challenging technical problem,primarily due to the unsuitability of the forming agent.The forming agent paraffin wax was modified through four types of modifiers,including organic high-molecular-mass resins,plasticizers,surfactants and lubricants.The qualitative screening of resin types was explored and an orthogonal experiment involving the combination of these four paraffin wax modifiers was conducted to obtain an optimized quantitative ratio of modifiers.The results reveal that the insertion of the small molecule chain of resin into the interstitial spaces of paraffin wax crystals is likely a crucial factor for improving the compatibility between the resin and paraffin wax.Through orthogonal experiments,the optimized formulation for the forming agent is determined:100 parts of 58#paraffin wax,15 parts of EVA-2,4 parts of DPHP,4 parts of oleic acid amide and 2 parts of stearic acid.This optimized formulation is applied to industrial production at one Chinese company,and qualified deep well-shaped cemented carbide products are achieved,which contain 90wt%WC and 10wt%Co.展开更多
The challenge of high temperatures in deep mining remains harmful to the health of workers and their production efficiency The addition of phase change materials (PCMs) to filling slurry and the use of the cold storag...The challenge of high temperatures in deep mining remains harmful to the health of workers and their production efficiency The addition of phase change materials (PCMs) to filling slurry and the use of the cold storage function of these materials to reduce downhole temperatures is an effective approach to alleviate the aforementioned problem.Paraffin–CaCl_(2)·6H_(2)O composite PCM was prepared in the laboratory.The composition,phase change latent heat,thermal conductivity,and cemented tailing backfill (CTB) compressive strength of the new material were studied.The heat transfer characteristics and endothermic effect of the PCM were simulated using Fluent software.The results showed the following:(1) The new paraffin–CaCl_(2)·6H_(2)O composite PCM improved the thermal conductivity of native paraffin while avoiding the water solubility of CaCl_(2)·6H_(2)O.(2) The calculation formula of the thermal conductivity of CaCl_(2)·6H_(2)O combined with paraffin was deduced,and the reasons were explained in principle.(3) The“enthalpy–mass scale model”was applied to calculate the phase change latent heat of nonreactive composite PCMs.(4)The addition of the paraffin–CaCl_(2)·6H_(2)O composite PCM reduced the CTB strength but increased its heat absorption capacity.This research can give a theoretical foundation for the use of heat storage backfill in green mines.展开更多
BACKGROUND Small bowel bezoar obstruction(SBBO)is a rare clinical condition characterized by hard fecal masses in the small intestine,causing intestinal obstruction.It occurs more frequently in the elderly and bedridd...BACKGROUND Small bowel bezoar obstruction(SBBO)is a rare clinical condition characterized by hard fecal masses in the small intestine,causing intestinal obstruction.It occurs more frequently in the elderly and bedridden patients,but can also affect those with specific gastrointestinal dysfunctions.Diagnosing SBBO is challenging due to its clinical presentation,which mimics other intestinal obstructions.While surgical intervention is the typical treatment for SBBO,advancements in endo-scopic techniques have led to increased use of non-surgical methods,such as endoscopic lithotripsy.CASE SUMMARY We report a case of small bowel obstruction induced by a phytobezoar.A 49-year-old male with a history of type 2 diabetes and long-term persimmon consumption presented to the hospital with symptoms of vomiting,abdominal distension,and constipation.Computed tomography revealed a small bowel obstruction with foreign bodies.Double balloon enteroscopy identified a phytobezoar blocking the intestinal lumen.The bezoar was successfully fragmented using a snare,and the fragments were treated with 100 mL of paraffin oil to facilitate their passage.This case report aims to enhance the understanding of this rare condition by detailing the clinical presentation,diagnostic process,and treatment outcomes of a patient with SBBO.Special attention is given to the application and effectiveness of non-surgical treatment methods,along with strategies to optimize patient manage-ment.CONCLUSION Double balloon enteroscopy combined with sequential laxative therapy is an effective approach for the treatment of a breakable phytobezoar.展开更多
With the advancement of oilfield extraction technology,since oil-water emulsions in waxy crude oil are prone to be deposited on the pipe wall,increasing the difficulty of crude oil extraction.In this paper,the mesosco...With the advancement of oilfield extraction technology,since oil-water emulsions in waxy crude oil are prone to be deposited on the pipe wall,increasing the difficulty of crude oil extraction.In this paper,the mesoscopic dissipative particle dynamics method is used to study themechanism of the crystallization and deposition adsorbed on thewall.The results show that in the absence of water molecules,the paraffin molecules near the substrate are deposited on themetallic surface with a horizontalmorphology,while the paraffin molecules close to the fluid side are arranged in a vertical column morphology.In the emulsified system,more water molecules will be absorbed on the metallic substrate than paraffin molecules,which obstructed the direct interaction between paraffin molecules and solid surface.Therefore,the addition of watermolecules hinders the crystallization of wax near the substrate.Perversely,on the fluid side,water molecules promote the formation of paraffin crystallization.The research in this paper reveals the crystallization mechanism of paraffin wax in oil-water emulsions in the pipeline from the microscopic scale,which provides theoretical support for improving the recovery of wax-containing crude oil and enhancing the transport efficiency.展开更多
Objective:The morphology analysis of whole-mount mouse embryos was observed using an improved paraffin section technique.Methods:Mouse embryos of varying embryonic ages were collected and whole-mount embryo paraffin s...Objective:The morphology analysis of whole-mount mouse embryos was observed using an improved paraffin section technique.Methods:Mouse embryos of varying embryonic ages were collected and whole-mount embryo paraffin sections were prepared using PFA-intravenously injected fixation,prolonged dehydration,and paraffin embedding.Hematoxylin and eosin(H&E)staining and immunohistochemical staining were employed to evaluate the quality of sections,with different tissues being observed labeled by CD34.Results:Following a series of tissue processing and staining procedures,the structure of the whole-mount mouse embryo was well-preserved,and the staining was clear and easily distinguishable.Embryos of different embryonic ages were treated differently,yet the quality of tissue processing remained highly consistent.Conclusion:Tissue processing and staining have been significantly improved,allowing for the easy acquisition of whole-mount mouse embryos of different ages through simplified methods of tissue fixation and dehydration duration.The staining results are clear and stable,providing technical support for the study of mouse embryo development.展开更多
[Objective] This study aimed to establish a new method for preparing paraffin sections of cattle eyebal s. [Method] The conventional method was used to prepare paraffin sections for cattle eyebal s in the control and ...[Objective] This study aimed to establish a new method for preparing paraffin sections of cattle eyebal s. [Method] The conventional method was used to prepare paraffin sections for cattle eyebal s in the control and a new method termed＆quot;opening a window on cornea and refixation＆quot; was used to prepare paraffin sections for cattle eyebal s in the treatment group. [Result] After the prepared specimens in the treatment group were fixed, it could be macroscopical y observed that retina and choroid were closely connected, with detachment occurring at a smal portion be-tween the two. According to the paraffin sections, it was microscopical y observed that the continuity of trabecular meshwork was intact, as wel as the continuity be-tween different layers of eyebal wal , without detachment between them, no retinal detachment, no shrinkage of each layer of tissue cells. [Conclusion] This study pro-vides a foundation for the basic research and pathological study of eyebal s.展开更多
Many specifications of paving asphalts are closely related to their colloidal stability, which is, however, determined by their exact chemical compositions. The Yumen vacuum residue (YVR), the bottoms of a paraffinic...Many specifications of paving asphalts are closely related to their colloidal stability, which is, however, determined by their exact chemical compositions. The Yumen vacuum residue (YVR), the bottoms of a paraffinic crude oil is unfit for the production of highway paving asphalts directly, Neither are the de-oiled asphalts of the YVR. In this research a blending method and an optimal process of solvent de-asphalts are adopted to investigate the feasibility of formulating highway-paving asphalts from YVR. Results show that highway paving asphalts are formulated by blending solvent de-oiled asphalts with one or more of the materials including YVR, decanted oil from FCC process, and furfural extracts from lubricating base stocks. Further investigations indicate that adding oil decanted from FCC process to the solvent de-asphalting process can increase the de-asphalted oil production, improve the de-oiled asphalts quality, and thus optimize the refinery processes. The methodology of this research can be extended even to refineries processing non-paraffinic crude oils.展开更多
[Objective]Preservation and waterproof treatment are two crucial parts in wood protection, which can not only extend the service time, but also expand the application range of wood products. [Method] This work combine...[Objective]Preservation and waterproof treatment are two crucial parts in wood protection, which can not only extend the service time, but also expand the application range of wood products. [Method] This work combined CA with paraffin wax emulsion to treat wood samples, and basic properties of the compound system, such as stability （storage stability and centrifugal stability）, particle size and pH val-ue, and water repel ency （water absorption, shrinkage and swel ing） of treated sam-ples were investigated. [Result and Conclusion] 1） the compound systems of CA and paraffin latex had a favorable miscibility and stability; 2） compared with untreated wood, CA-treated samples showed poor water repel ing properties, whereas samples treated with the compound systems indicated an obvious reduction in water absorp-tion, and the shrinkage and swel ing of them were improved as wel .展开更多
Atmospheric aerosol samples（PM2.5–0.3, i.e., atmospheric particles ranging from 0.3 to2.5 μm） were collected during two periods： spring–summer 2008 and autumn–winter 2008–2009, using high volume samplers equip...Atmospheric aerosol samples（PM2.5–0.3, i.e., atmospheric particles ranging from 0.3 to2.5 μm） were collected during two periods： spring–summer 2008 and autumn–winter 2008–2009, using high volume samplers equipped with cascade impactors. Two sites located in the Northern France were compared in this study： a highly industrialised city（Dunkirk） and a rural site（Rubrouck）. Physicochemical analysis of particulate matter（PM） was undertaken to propose parameters that could be used to distinguish the various sources and to exhibit seasonal variations but also to provide knowledge of chemical element composition for the interpretation of future toxicological studies. The study showed that PM2.5–0.3concentration in the atmosphere of the rural area remains stable along the year and was significantly lower than in the urban or industrial ones, for which concentrations increase during winter.High concentrations of polycyclic aromatic hydrocarbons（PAHs）, dioxins, furans and dioxin like polychlorinated biphenyls（DL-PCBs）, generated by industrial activities, traffic and municipal wastes incineration were detected in the samples. Specific criteria like Carbon Preference Index（CPI） and Combustion PAHs/Total PAHs ratio（CPAHs/TPAHs） were used to identify the possible sources of atmospheric pollution. They revealed that paraffins are mainly emitted by biogenic sources in spring–summer whereas as in the case of PAHs, they have numerous anthropogenic emission sources in autumn-winter（mainly from traffic and domestic heating）.展开更多
Short-chain chlorinated paraffins（SCCPs） are still controversial candidates for inclusion in the Stockholm Convention.The inherent mixture nature of SCCPs makes it rather difficult to explore their environmental beh...Short-chain chlorinated paraffins（SCCPs） are still controversial candidates for inclusion in the Stockholm Convention.The inherent mixture nature of SCCPs makes it rather difficult to explore their environmental behaviors.A virtual molecule library of 42,720 C10-SCCP congeners covering the full structure spectrum was constructed.We explored the structural effects on the thermodynamic parameters and environmental degradability of C10-SCCPs through semi-empirical quantum chemical calculations.The thermodynamic properties were acquired using the AM1 method,and frontier molecular orbital analysis was carried out to obtain the EHOMO,ELUMO and ELUMO-EHOMO for degradability exploration at the same level.The influence of the chlorination degree（NCl on the relative stability and environmental degradation was elucidated.A novel structural descriptor,μ,was proposed to measure the dispersion of the chlorine atoms within a molecule.There were significant correlations between thermodynamic values and NCl,while the reported NCl-dependent pollution profile of C10-SCCPs in environmental samples was basically consistent with the predicted order of formation stability of C10-SCCP congeners.In addition,isomers with largeμ showed higher relative stability than those with small μ.This could be further verified by the relationship between μ and the reactivity of nucleophilic substitution and · OH attack respectively.The C10-SCCP congeners with less Cl substitution and lower dispersion degree are susceptible to environmental degradation via nucleophilic substitution and hydroxyl radical attack,while direct photolysis of C10-SCCP congeners cannot readily occur due to the large ELUMO-EHOMO values.The chlorination effect and the conclusions were further checked with appropriate density functional theory（DFT） calculations.展开更多
基金supported by the National Natural Science Foundation of China (No.21337002)the National Basic Research Program (973) of China (No.2015CB453100)
文摘Short-chain chlorinated paraffins(SCCPs) are produced in high volume and have the high potential to pose a threat to human health. However, little information is available for SCCP contamination in human blood/plasma/serum, mainly due to the difficulty of sample preparation and quantitative analysis. A method using high resolution gas chromatography coupled with electron capture negative ionization low resolution mass spectrometry(HRGC–ECNI/LRMS) was developed and validated to measure SCCPs in human plasma. The pretreatment process included protein denaturation and lipid elimination, liquid–liquid extraction with a mixture of n-hexane/dichloromethane(1:1, V/V), and cleanup on a multilayer silica column. The blank controls, including procedural blank, vacuum blood collection tube blank, and instrumental blank, were the most pivotal points for the reliable analysis of SCCPs. The average value of procedural blanks was 9.0 ng/g; and the method detection limit(MDL), calculated as the sum of the average procedural blank value and 3 times of the standard deviation of the procedural blanks, was 12.6 ng/g plasma. The validated method was applied to measure the concentrations of the total SCCPs(∑ SCCPs) in50 plasma samples from a general population. The measured plasma concentrations of ∑SCCPs ranged from <MDL to 203 ng/g wet weight(ww), with an average value of 32.0 ng/g ww.The relative abundance profiles of SCCPs in plasma samples were dominated by C10- and C11-CP congener groups centered on Cl6–7. The developed method can be used for the comprehensive and large-scale investigation of SCCP levels in human plasma.
基金supported by the National Natural Science Foundation of China (Nos.21625702,21337002,21621064)the National Basic Research Program of China (No.2015CB453102)the Strategic Priority Research Program of the Chinese Academy of Sciences (No.XDB14010400)
文摘The increasing production and usage of chlorinated paraffins(CPs) correspondently increase the amount of CPs that experience thermal processes. Our previous study revealed that a significant amount of medium-chain chlorinated paraffins(MCCPs), short-chain chlorinated paraffins(SCCPs) as well as aromatic and chlorinated polycyclic aromatic hydrocarbons(Cl-PAHs) were formed synergistically during the thermal decomposition of CP-52(a class of CP products).However, the transformation mechanisms of CP-52 to these compounds are still not very clear.This article presents a mechanistic analysis on the decomposition of CP-52 experimentally and theoretically. It was found that CP-52 initially undergoes dehydrochlorination and carbon chain cleavage and it transformed into chlorinated and unsaturated hydrocarbons. Cyclization and aromatization were the most accessible pathways at low temperatures(200–400°C), both of which produce mostly aromatic hydrocarbons. As the temperature exceeds 400°C, the hydrocarbons could decompose into small molecules, and the subsequent radical-induced reactions become the predominant pathways, leading to the formation of Cl-PAHs. The decomposition of CP-52 was investigated by using density functional theory and calculations demonstrating the feasibility and rationality of PCB and PCN formation from chlorobenzene. The results improve the understanding of the transformation processes from CP-52 to SCCPs and Cl-PAHs as well as provide data for reducing their emissions during thermal-related processes.
基金supported by the National Natural Science Foundation of China(Nos.21625702,21337002,21621064)the National Basic Research Program of China(No.2015CB453102)the Strategic Priority Research Program of the Chinese Academy of Science(No.XDB14010400)for the joint financial support
文摘Chlorinated paraffins（SCCPs） are widely used worldwide, and they can be released into the environment during their production, transport, usage and disposal, which pose potential risks for human health. In this work, an efficient, reliable and rapid pretreatment method based on matrix solid-phase dispersion（MSPD） was developed for the analysis of short-chain CPs（SCCPs） in human placenta by gas chromatograph-electron capture negative ion low-resolution mass spectrometry（GC-ECNI-LRMS） and gas chromatography–quadrupole time-of-flight mass spectrometry（GC–QTOF-HRMS）. The MSPD-relevant parameters including dispersing sorbent,sample-to-sorbent mass ratio, and elution solvent were optimized using the orthogonal test.Silica gel was found to be the optimal dispersing sorbent among the selected matrices. Under the optimal conditions, 44% acidic silica gel can be used as the co-sorbent to remove lipid and eluted by the mixture of hexane and dichloromethane（7：3, V/V）. The spiked recoveries of the optimized method were 77.4% and 91.4% for analyzing SCCPs in human placenta by GC-ECNI-LRMS and GC–QTOF-HRMS, and the corresponding relative standard deviations were10.2% and 5.6%, respectively. The method detection limit for the total SCCPs was 36.8 ng/g（dry weight, dw） and 19.2 ng/g（dw） as measured by GC-ECNI-LRMS and GC–QTOF-HRMS,respectively. The concentrations of SCCPs in four human placentas were in the range of
基金the Strategic Priority Research Program of the Chinese Academy of Sciencesthe Pan-Third Pole Environment Study for a Green Silk Road(Pan-TPE)(No.XDA2004050203)+3 种基金the Second Tibetan Plateau Scientific Expedition and Research Program(No.2019QZKK0605)the National Natural Science Foundation of China(No.21906096)the Youth Science Funds of Shandong Academy of Sciences(No.2019QN008)the Youth Innovation Promotion Association of CAS(No.2018052)。
文摘Pristine alpine regions are ideal regions for investigating the long-range atmospheric transport and cold trapping effects of short chain chlorinated paraffins(SCCPs).The concentrations and alpine condensation of SCCPs were investigated in lichen samples collected from the southeastern Tibetan Plateau.The concentrations of SCCPs ranged from 3098 to 6999 ng/g lipid weight(lw)and appeared to have an increasing trend with altitude.For congeners,C10 dominated among all the congener groups.The different environmental behavior for different congener groups was closely related to their octanol-air partition coefficient(Koa).C10 congeners showed an increasing trend with altitude,whereas C13 congeners were negatively correlated with altitude.Volumetric bioconcentration factors(BCF)of SCCPs reached 8.71 in lichens,which were higher than other semivolatile organic compounds(SVOCs)such as organochlorine pesticides(OCPs),polybrominated diphenyl ethers(PBDEs),polychlorinated biphenyls(PCBs),and hexabromocyclododecane(HBCD).These results suggested that SCCPs were prone to accumulate in the lichen from the air and provided evidence for the role of lichens as a suitable atmospheric indicator in the Tibetan Plateau.
基金the Chinese Academy of Sciences (KZCX2-YW-BR-25, XDB14030500, YSW2013B01)the National High Technology Research and Development Program of China (2013AA065201)
文摘Short chain chlorinated paraffins （SCCPs） are not only research focus of environmental issues but also interesting model mol- ecules for organic chemistry which exhibit diverse conformation preference and intramolecular noncovalent interactions （NCIs）. A systematic study was conducted to reveal the conlk）rmation preference and the related intramolecular NCIs in two C^-isomers of SCCPs, 5,5,6,6-tetrachlorodecane and 4,4,6,6-1etrachlorodecane. The overall conformation profile was deter- mined on the basis of relative energies calculated at the MP2/6-311＋＋G（d,p） level with the geometries optimized by B3LYP/6-31 l＋＋G（d,p） method. Then, quantum theory of atoms in molecules （QTAIM） has been adopted to identify the NCls in the selected conformers of the model molecules at both B31~YP/6-31 l＋＋G（d,p） and M06-2X/aug-cc-pvdz level. Different chlorine substitution modes result in varied conformation preference. No obvious gauche effect can be observed tk）r the SCCPs with chlorination on adjacent carbon atoms. The most stable conformer of 5,5,6,6-tetrachlorodecane （tTt） has its three dihedral angles in the T configuration, and there is no intramolecular N（3s found in this molecule. On the contrary, the chlorination on interval carbon atoms favors the adoption of gauche configmation for the H C C CI axis. Not only inlramolecular H-..CI contacts but also H---H interactions have been identified as driving forces to compensate the instability from steric crowding ot the gauche configuration. The gggg and g＇g＇g＇g＇ conformers are the most popular ones, while the populations of tggg and tg＇g＇g＇ conformer are second to those of the gggg and g＇g＇g＇g＇ conformers. Meanwhile, the M06-2X method with large basis sets is preferred for identification of subtle intramolecular NCIs in large molecules like SCCPs.
基金the National Natural Science Foundation of China(grant nos.21707164 and 3187131629)the Central Public Interest Scientific Institution Basal Research Fund of the Chinese Academy of Agricultural Sciences(grant no.Y2020PT38).
文摘Chlorinated paraffins(CPs)are produced in large amounts and used worldwide.Dietary intake is the primary pathway for the exposure of pets to CPs,but limited information is available concerning the potential contamination of pet food by CPs.In the present study,the concentrations and congener group profiles of short-chain CPs(SCCPs)and medium-chain CPs(MCCPs)were assessed in 35 imported commercial dry cat and dog foods collected in China,and the estimated daily intakes of SCCPs and MCCPs for cats and dogs through the consumption of such foods was calculated.The concentrations of SCCPs and MCCPs in the cat and dog foods were determined to be in the ranges of 108e45,300 ng/g(median:1340 ng/g)and 3.8e52,700 ng/g(median:11 ng/g),respectively.The predominant congener groups were C10Cl6 for SCCPs and C14Cl7-8 for MCCPs.The high levels of CPs found in certain pet foods suggest the potential for adverse health effects.
基金supported by the National Natural Science Foundation of China(Grant No.52274061&52004039&51974037)China Postdoctoral Science Foundation(Grant No.2023T160717&2021M693908)+2 种基金CNPC Innovation Found(Grant No.2022DQ02-0501),Changzhou Applied Basic Research Program(Grant No.CJ20230030)The major project of universities affiliated with Jiangsu Province basic science(natural science)research(Grant No.21KJA440001)Jiangsu Qinglan Project,Changzhou Longcheng Talent Plan-Youth Science and Technology Talent Recruitment Project。
文摘Oil-gas two phase wax deposition is a fairly common and open-ended question in flow assurance of multiphase transportation pipelines.This paper investigated the two main aspects of oil-gas two phase wax deposition layer:apparent thickness and crystal structure characteristics.A typical highly paraffinic oil in Bohai Sea,China,was used as the experimental material to investigate the wax deposition thickness in oil-gas two phase under the influence of different oil temperatures,superficial gas/liquid phase velocities and gas-oil ratios by using multiphase flow loop experimental device.Just as in the classical theory of wax molecular diffusion,it showed that wax deposition thickness of oil-gas two phase increased with increasing oil temperature.Analysis of the impact of different superficial phase velocities found that the actual liquid flow heat transfer and shear stripping was the gas phase dominant mechanisms determining wax deposit thickness.In addition,the crystal structure of the wax deposition layer was characterized with the help of small-angle X-ray scattering(SAXS)for different circumferential positions,flow rates and gas-oil ratios.The bottom deposition layer had a complex crystal structure and high hardness,which were subject to change over flow rate variations.Furthermore,the SAXS results provided evidence that the indirect effect of the actual liquid velocity modified by the gas phase was the main mechanism.Our study of the effect of gas phase on the wax deposition of oil-gas two phase will help shed light onto the mechanism by which this important process occurs.Our findings address a very urgent need in the field of wax deposition of highly paraffinic oil to understand the flow security of oilgas two phase that occurs easily in multiphase field pipelines.
基金The National Natural Science Foundation of China(No.52122802,52078126)Jiangsu Provincial Department of Science and Technology Innovation Support Program(No.BK20222004,BZ2022036).
文摘The novel calcium-silicate-hydrate(C-S-H)/paraffin composite phase change materials were synthesized using a discontinuous two-step nucleation method.Initially,the C-S-H precursor is separated and dried,followed by immersion in an aqueous environment to transform it into C-S-H.This two-step nucleation approach results in C-S-H with a specific surface area of 497.2 m^(2)/g,achieved by preventing C-S-H foil overlapping and refining its pore structure.When impregnated with paraffin,the novel C-S-H/paraffin composite exhibits superior thermal properties,such as a higher potential heat value of 148.3 J/g and an encapsulation efficiency of 81.6%,outperforming conventional C-S-H.Moreover,the composite material demonstrates excellent cyclic performance,indicating its potential for building thermal storage compared to other paraffin-based composites.Compared with the conventional method,this simple technology,which only adds conversion and centrifugation steps,does not negatively impact preparation costs,the environment,and resource consumption.This study provides valuable theoretical insights for designing thermal storage concrete materials and advancing building heat management.
基金supported by various grants including the Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2021A1515111155 and 2022A1515111200)Basic Research Programs of Taicang(Grant Nos.TC2023JC03 and TC2022JC08)+2 种基金Natural Science Foundation of Shaanxi Province(Grant No.2023JC-QN-0380)Nantong Natural Science Foundation(Grant No.JC2023011)Shanghai Central Guidance Fund for Local Science and Technology Development(Grant No.YDZX20233100004009)。
文摘SiC aerogel presents several advantageous features like lightweight and high temperature resistance when applied as microwave absorbing material.In this paper,SiC aerogel was prepared eventually followed by the sol-gel and carbonization reduction process.The results showed that the effective electromagnetic microwave absorption capacity of SiC aerogel was highly increased after being pyrolyzed at 1500℃,which presented a minimum reflection loss value of-57.80 dB at 3.10 mm and 9.86 GHz.Besides,the electromagnetic parameters of SiC aerogel with different paraffin ratios were discussed as well as the varying electromagnetic microwave absorption performances.The minimum reflection loss value first rose then fell as the SiC/paraffin ratio increased,which demonstrated the importance of SiC content.This study establishes the theoretical foundation for the subsequent functional application of SiC aerogel.
文摘The production of deep well-shaped WC-Co cemented carbide blocks via industrial powder pressing remains a challenging technical problem,primarily due to the unsuitability of the forming agent.The forming agent paraffin wax was modified through four types of modifiers,including organic high-molecular-mass resins,plasticizers,surfactants and lubricants.The qualitative screening of resin types was explored and an orthogonal experiment involving the combination of these four paraffin wax modifiers was conducted to obtain an optimized quantitative ratio of modifiers.The results reveal that the insertion of the small molecule chain of resin into the interstitial spaces of paraffin wax crystals is likely a crucial factor for improving the compatibility between the resin and paraffin wax.Through orthogonal experiments,the optimized formulation for the forming agent is determined:100 parts of 58#paraffin wax,15 parts of EVA-2,4 parts of DPHP,4 parts of oleic acid amide and 2 parts of stearic acid.This optimized formulation is applied to industrial production at one Chinese company,and qualified deep well-shaped cemented carbide products are achieved,which contain 90wt%WC and 10wt%Co.
基金financial support provided by the National Natural Science Foundation of China (No. 52174106)the Key Technology Research and Development Program (No. 2022YFC2905102)。
文摘The challenge of high temperatures in deep mining remains harmful to the health of workers and their production efficiency The addition of phase change materials (PCMs) to filling slurry and the use of the cold storage function of these materials to reduce downhole temperatures is an effective approach to alleviate the aforementioned problem.Paraffin–CaCl_(2)·6H_(2)O composite PCM was prepared in the laboratory.The composition,phase change latent heat,thermal conductivity,and cemented tailing backfill (CTB) compressive strength of the new material were studied.The heat transfer characteristics and endothermic effect of the PCM were simulated using Fluent software.The results showed the following:(1) The new paraffin–CaCl_(2)·6H_(2)O composite PCM improved the thermal conductivity of native paraffin while avoiding the water solubility of CaCl_(2)·6H_(2)O.(2) The calculation formula of the thermal conductivity of CaCl_(2)·6H_(2)O combined with paraffin was deduced,and the reasons were explained in principle.(3) The“enthalpy–mass scale model”was applied to calculate the phase change latent heat of nonreactive composite PCMs.(4)The addition of the paraffin–CaCl_(2)·6H_(2)O composite PCM reduced the CTB strength but increased its heat absorption capacity.This research can give a theoretical foundation for the use of heat storage backfill in green mines.
文摘BACKGROUND Small bowel bezoar obstruction(SBBO)is a rare clinical condition characterized by hard fecal masses in the small intestine,causing intestinal obstruction.It occurs more frequently in the elderly and bedridden patients,but can also affect those with specific gastrointestinal dysfunctions.Diagnosing SBBO is challenging due to its clinical presentation,which mimics other intestinal obstructions.While surgical intervention is the typical treatment for SBBO,advancements in endo-scopic techniques have led to increased use of non-surgical methods,such as endoscopic lithotripsy.CASE SUMMARY We report a case of small bowel obstruction induced by a phytobezoar.A 49-year-old male with a history of type 2 diabetes and long-term persimmon consumption presented to the hospital with symptoms of vomiting,abdominal distension,and constipation.Computed tomography revealed a small bowel obstruction with foreign bodies.Double balloon enteroscopy identified a phytobezoar blocking the intestinal lumen.The bezoar was successfully fragmented using a snare,and the fragments were treated with 100 mL of paraffin oil to facilitate their passage.This case report aims to enhance the understanding of this rare condition by detailing the clinical presentation,diagnostic process,and treatment outcomes of a patient with SBBO.Special attention is given to the application and effectiveness of non-surgical treatment methods,along with strategies to optimize patient manage-ment.CONCLUSION Double balloon enteroscopy combined with sequential laxative therapy is an effective approach for the treatment of a breakable phytobezoar.
基金sponsored by Natural Science Foundation of Xinjiang Uygur Autonomous Region,Grant No.2023D01C197Performance Incentive Guidance Project of Chongqing Scientific Research Institutions(cstc2022jxjl20016).
文摘With the advancement of oilfield extraction technology,since oil-water emulsions in waxy crude oil are prone to be deposited on the pipe wall,increasing the difficulty of crude oil extraction.In this paper,the mesoscopic dissipative particle dynamics method is used to study themechanism of the crystallization and deposition adsorbed on thewall.The results show that in the absence of water molecules,the paraffin molecules near the substrate are deposited on themetallic surface with a horizontalmorphology,while the paraffin molecules close to the fluid side are arranged in a vertical column morphology.In the emulsified system,more water molecules will be absorbed on the metallic substrate than paraffin molecules,which obstructed the direct interaction between paraffin molecules and solid surface.Therefore,the addition of watermolecules hinders the crystallization of wax near the substrate.Perversely,on the fluid side,water molecules promote the formation of paraffin crystallization.The research in this paper reveals the crystallization mechanism of paraffin wax in oil-water emulsions in the pipeline from the microscopic scale,which provides theoretical support for improving the recovery of wax-containing crude oil and enhancing the transport efficiency.
基金the funding of Department of Education of Guangdong Province,China(Grant No.2020KTSCX036Grant No.2023A1515010544)Health Commission of Guangdong Province(A2023342).
文摘Objective:The morphology analysis of whole-mount mouse embryos was observed using an improved paraffin section technique.Methods:Mouse embryos of varying embryonic ages were collected and whole-mount embryo paraffin sections were prepared using PFA-intravenously injected fixation,prolonged dehydration,and paraffin embedding.Hematoxylin and eosin(H&E)staining and immunohistochemical staining were employed to evaluate the quality of sections,with different tissues being observed labeled by CD34.Results:Following a series of tissue processing and staining procedures,the structure of the whole-mount mouse embryo was well-preserved,and the staining was clear and easily distinguishable.Embryos of different embryonic ages were treated differently,yet the quality of tissue processing remained highly consistent.Conclusion:Tissue processing and staining have been significantly improved,allowing for the easy acquisition of whole-mount mouse embryos of different ages through simplified methods of tissue fixation and dehydration duration.The staining results are clear and stable,providing technical support for the study of mouse embryo development.
基金Supported by China Agriculture Research System(CARS-38)~~
文摘[Objective] This study aimed to establish a new method for preparing paraffin sections of cattle eyebal s. [Method] The conventional method was used to prepare paraffin sections for cattle eyebal s in the control and a new method termed＆quot;opening a window on cornea and refixation＆quot; was used to prepare paraffin sections for cattle eyebal s in the treatment group. [Result] After the prepared specimens in the treatment group were fixed, it could be macroscopical y observed that retina and choroid were closely connected, with detachment occurring at a smal portion be-tween the two. According to the paraffin sections, it was microscopical y observed that the continuity of trabecular meshwork was intact, as wel as the continuity be-tween different layers of eyebal wal , without detachment between them, no retinal detachment, no shrinkage of each layer of tissue cells. [Conclusion] This study pro-vides a foundation for the basic research and pathological study of eyebal s.
文摘Many specifications of paving asphalts are closely related to their colloidal stability, which is, however, determined by their exact chemical compositions. The Yumen vacuum residue (YVR), the bottoms of a paraffinic crude oil is unfit for the production of highway paving asphalts directly, Neither are the de-oiled asphalts of the YVR. In this research a blending method and an optimal process of solvent de-asphalts are adopted to investigate the feasibility of formulating highway-paving asphalts from YVR. Results show that highway paving asphalts are formulated by blending solvent de-oiled asphalts with one or more of the materials including YVR, decanted oil from FCC process, and furfural extracts from lubricating base stocks. Further investigations indicate that adding oil decanted from FCC process to the solvent de-asphalting process can increase the de-asphalted oil production, improve the de-oiled asphalts quality, and thus optimize the refinery processes. The methodology of this research can be extended even to refineries processing non-paraffinic crude oils.
基金Supported by Beijing Municipal Student Research Training Program in Beijing ForestryUniversity(S201310022020)Fundamental Research Funds for the Central Universities(TD2011-14)~~
文摘[Objective]Preservation and waterproof treatment are two crucial parts in wood protection, which can not only extend the service time, but also expand the application range of wood products. [Method] This work combined CA with paraffin wax emulsion to treat wood samples, and basic properties of the compound system, such as stability （storage stability and centrifugal stability）, particle size and pH val-ue, and water repel ency （water absorption, shrinkage and swel ing） of treated sam-ples were investigated. [Result and Conclusion] 1） the compound systems of CA and paraffin latex had a favorable miscibility and stability; 2） compared with untreated wood, CA-treated samples showed poor water repel ing properties, whereas samples treated with the compound systems indicated an obvious reduction in water absorp-tion, and the shrinkage and swel ing of them were improved as wel .
基金supported by the French Agency AFSSET(contract EST-2007-48)and the“Institut de Recherche en ENvironnement Industriel”(IRENI)which is financially supported by the Nord-Pas-de-Calais Region Council,the Ministry of Higher Education and Researchthe European Regional Development Funds
文摘Atmospheric aerosol samples（PM2.5–0.3, i.e., atmospheric particles ranging from 0.3 to2.5 μm） were collected during two periods： spring–summer 2008 and autumn–winter 2008–2009, using high volume samplers equipped with cascade impactors. Two sites located in the Northern France were compared in this study： a highly industrialised city（Dunkirk） and a rural site（Rubrouck）. Physicochemical analysis of particulate matter（PM） was undertaken to propose parameters that could be used to distinguish the various sources and to exhibit seasonal variations but also to provide knowledge of chemical element composition for the interpretation of future toxicological studies. The study showed that PM2.5–0.3concentration in the atmosphere of the rural area remains stable along the year and was significantly lower than in the urban or industrial ones, for which concentrations increase during winter.High concentrations of polycyclic aromatic hydrocarbons（PAHs）, dioxins, furans and dioxin like polychlorinated biphenyls（DL-PCBs）, generated by industrial activities, traffic and municipal wastes incineration were detected in the samples. Specific criteria like Carbon Preference Index（CPI） and Combustion PAHs/Total PAHs ratio（CPAHs/TPAHs） were used to identify the possible sources of atmospheric pollution. They revealed that paraffins are mainly emitted by biogenic sources in spring–summer whereas as in the case of PAHs, they have numerous anthropogenic emission sources in autumn-winter（mainly from traffic and domestic heating）.
基金jointly supported by the Chinese Academy of Sciences (Nos. KZCX2-YW-BR-25, XDB14030500 and YSW2013B01)the National High Technology Research and Development Program (863) of China (No. 2013AA065201)
文摘Short-chain chlorinated paraffins（SCCPs） are still controversial candidates for inclusion in the Stockholm Convention.The inherent mixture nature of SCCPs makes it rather difficult to explore their environmental behaviors.A virtual molecule library of 42,720 C10-SCCP congeners covering the full structure spectrum was constructed.We explored the structural effects on the thermodynamic parameters and environmental degradability of C10-SCCPs through semi-empirical quantum chemical calculations.The thermodynamic properties were acquired using the AM1 method,and frontier molecular orbital analysis was carried out to obtain the EHOMO,ELUMO and ELUMO-EHOMO for degradability exploration at the same level.The influence of the chlorination degree（NCl on the relative stability and environmental degradation was elucidated.A novel structural descriptor,μ,was proposed to measure the dispersion of the chlorine atoms within a molecule.There were significant correlations between thermodynamic values and NCl,while the reported NCl-dependent pollution profile of C10-SCCPs in environmental samples was basically consistent with the predicted order of formation stability of C10-SCCP congeners.In addition,isomers with largeμ showed higher relative stability than those with small μ.This could be further verified by the relationship between μ and the reactivity of nucleophilic substitution and · OH attack respectively.The C10-SCCP congeners with less Cl substitution and lower dispersion degree are susceptible to environmental degradation via nucleophilic substitution and hydroxyl radical attack,while direct photolysis of C10-SCCP congeners cannot readily occur due to the large ELUMO-EHOMO values.The chlorination effect and the conclusions were further checked with appropriate density functional theory（DFT） calculations.
