Ultrafine full-vulcanized polybutadiene rubber（UFBR） with particle sizes of ca.50―100 nm were used for modifying mechanical and processing performances of polypropylene（PP） with PP-g-maleic anhydride（PP-g-MA） a...Ultrafine full-vulcanized polybutadiene rubber（UFBR） with particle sizes of ca.50―100 nm were used for modifying mechanical and processing performances of polypropylene（PP） with PP-g-maleic anhydride（PP-g-MA） as a compatibilizer for enhancing the interfacial adhesion between the two components.The morphology,dynamical rheology response and mechanical properties of the blends were characterized by means of SEM,rheometer and tensile test,respectively.The results show that the ternary PP/UFBR blends compatibilized with PP-g-MA possess rheological behaviors like highly branched PP,while no obvious strain hardening is observed in its control binary PP/UFBR blends,a low level of PP-g-MA in PP/UFBR blends can even endow the material with rheological characteristics of high melt strength materials like highly branched PP.The enhancement interfacial interaction between the UFBR particles and PP matrix accounting for the rheological behavior of compatibilized blends and effectiveness of PP-g-MA were proposed and proved.展开更多
An anomalous phase containing clays and humic acid was found while extraction humic acid from samples of weathering crust of REE-bearing granites by using 0.1 mol/L NaOH solution.Studied by chemical separation experim...An anomalous phase containing clays and humic acid was found while extraction humic acid from samples of weathering crust of REE-bearing granites by using 0.1 mol/L NaOH solution.Studied by chemical separation experiments,column chromatography,ion-exchange chromatography,infrared spectrum.fluorescence spectrum,polarimicroscopic testing and elemental determination by ultraviolet-visible spectrometer and atomic absorption spectrometer.it was proved to be a compound of humic acid and clays which are connected in the form of bridge by heteronuclearpolynuclear complexing ions formed by cations of RE￣(5+),Al￣(3+).Fe￣(3+) etc.The compounding pattern was further proved by the experiment for compounding humic acid,REE and kaolinite.展开更多
To improve the quality of ultrasonic elastography, by taking the advantage of code excitation and frequency compounding, a transmitting-side multi-frequency with coded excitation for elastography （TFCCE） was propose...To improve the quality of ultrasonic elastography, by taking the advantage of code excitation and frequency compounding, a transmitting-side multi-frequency with coded excitation for elastography （TFCCE） was proposed. TFCCE adopts the chirp signal excitation scheme and strikes a balance in the selection of sub-signal bandwidth, the bandwidth overlap and the number of sub-strain image based on theoretical derivation, so as to further improve the quality of elastic image. Experiments have proved that, compared with the other optimizing methods, the elastographyic signal-to-noise ratio（Re-SN） and contrast-to-noise ratio（Re-CN） are improved significantly with different echo signal-to-noise ratios （ReSN） and attenuation coefficients. When ReSN is 50 dB, compared with short pulse, Rc-SN and Re-CN obtained by TFCCE increase by 53% and 143%, respectively. Moreover, in a deeper investigation （85-95 mm）, the image has lower strain noise and clear details. When the attenuation coefficient is in the range of 0-1 dB/（cm.MHz）, Re-SN and Re-CN obtained by TFCCE can be kept in moderate ranges of 5〈Re-SN〈6.8 and 11.4〈Re-CN〈15.2, respectively. In particular, for higher tissue attenuation, the basic image quality cannot be ensured with short pulse excitation, while mediocre quality strain figure can be obtained by TFCCE. Therefore, the TFCCE technology can effectively improve the elastography quality and can be applied to ultrasonic clinical trials.展开更多
In order to observe the effects of the ground and intact Zhi Zi (Fructus Gardeniae) and different combinations of the ingredients and refined single Chinese drug granules in Yin Chen Hao Decoction compound prescriptio...In order to observe the effects of the ground and intact Zhi Zi (Fructus Gardeniae) and different combinations of the ingredients and refined single Chinese drug granules in Yin Chen Hao Decoction compound prescription on the contents of gardenoside (an effective component of the prescription), the contents of gardenoside were determined with reversed phase high performance liquid chromatography (HPLC), with acetonitrile-water (15:85) as mobile phase, at wave length 238nm. The results indicated that the gardenoside-decocted-out rates in the decoctions prepared by different combinations of the ingredients with the ground Zhi Zi (Fructus Gardeniae) all were higher significantly than those in the decoction with intact Zhi Zi (Fructus Gardeniae), and generally, different combinations of the ingredients in the decoction had only little effect on the gardenoside-decocted-out rate.展开更多
Aiming at the problem of runner unbalance in the compounding cavity of the upper and lower cover of the correction tape box, the plastic injection analysis software Moldflow was used to optimize runner balance. First,...Aiming at the problem of runner unbalance in the compounding cavity of the upper and lower cover of the correction tape box, the plastic injection analysis software Moldflow was used to optimize runner balance. First, the 3D modeling software Proe was used to establish the geometric model of the upper and lower cover of the correction tape box, and introduced into the plastic injection analysis software Moldflow. Secondly, the upper and the lower cover of the correction tape box were meshed and the initial gating system was designed in Moldflow. Filling analysis of the initial scheme of the correction tape box combined cavity showed that the runner of the melt was not balanced in the mold cavity. Finally, the runner balance optimization analysis of the cavities was carried out. Through optimization, the time unbalance rate of the melt in the mold cavity decreased from 28.6% to 0.7%, the pressure unbalance rate decreased from 42.0% to 4.2%, and the pressure distribution in the cavity was more uniform in the whole injection process.展开更多
This study aims to find the compound registers that are used among the Farm-Centre cell-phone marketers,analyse their compounding morphological structures,and explain the meaning they convey.The Farm-Centre Cell-phone...This study aims to find the compound registers that are used among the Farm-Centre cell-phone marketers,analyse their compounding morphological structures,and explain the meaning they convey.The Farm-Centre Cell-phone Market is located in Kano metropolis,the largest city of Northern Nigeria.The study employs an ethnographic method of data collection and adopts Abubakar(2000)as a model of approach when analysing the structures of the compound registers.It is found that the registers have the following six morphological compound structures:(i)Genitive-based compounds[LG+N]N,(ii)Noun-based compounds[N+GL+N]N,(iii)Adjective-based compounds[Adj+N]N,(iv)Diminutive-based compounds[Dim+N]N,(v)Particle dà‘with’compounds[dà+N]N,(vi)Verb-based compounds[V+VN/Prep]V.Moreover,the registers are so special among the marketers because they convey meanings that are irrelevant to the conventional meanings known by the general speakers of the Hausa language.展开更多
In English language,affixation is a significant way of forming new words,This essay intends to explore the concepts of two fundamental ways of forming new words,namely,derivation and compounding.They are different in ...In English language,affixation is a significant way of forming new words,This essay intends to explore the concepts of two fundamental ways of forming new words,namely,derivation and compounding.They are different in a lot of cases,yet,it is also argued that there is a clear dividing line between compounding and derivation.展开更多
In recent decades,Southwest China(SWC)has suffered from frequent super droughts,leading to severe economic losses and ecological degradation.This study investigates the characteristics of super droughts in SWC during ...In recent decades,Southwest China(SWC)has suffered from frequent super droughts,leading to severe economic losses and ecological degradation.This study investigates the characteristics of super droughts in SWC during 1961-2022,reveals the compounding effect of multiscalar anomalies,and explores the plausible atmospheric circulation mechanisms responsible.The nature of super drought is a compound drought caused by the superposition of extreme drought events across multiple time scales.By contrasting the typical drought cases in 2006 and 2022,the decisive role of multiscalar drought compounding is confirmed.Based on the Comprehensive Multiscalar Index(CMI),multiple super drought events in SWC were identified to be temporally clustered during 2006-2014.Among them,the decadal background of enhanced evaporation and precipitation deficit at long time scales is a necessary condition for shaping the overall pattern of super droughts,while the precipitation and evaporation anomalies at short time scales trigger the outbreak of super droughts,determining the exact timing of occurrence.These events include August-September 2006,November 2009 to May 2010,July-October 2011,April-May 2012,January-April 2013,etc.Statistical results suggest that the contribution of superposed precipitation anomalies to super drought is 2.4 times that of evaporation.As regards the circulation mechanisms affecting multiscalar precipitation,the anomalous spatial patterns at short-term and long-term scales are similar,featuring the cyclonic circulation over the South China Sea and the northeasterly wind anomalies together with the subsidence center over SWC.During 2006-2014,the possible causes for the cross-seasonal persistent precipitation reduction in SWC are the extreme negative phase of the Pacific Decadal Oscillation(PDO)in the North Pacific as well as the pronounced warming of the warm pool in the western Pacific.The key dynamic processes are outlined as follows.On the one hand,the negative PDO phase generates anomalous anticyclonic circulation in the North Pacific,with the northeasterly winds on its southwest flank extending to Southeast Asia,hindering moisture transport into SWC.On the other hand,the warming of the warm pool excites anomalous cyclonic circulation to its northwest,also giving rise to northeasterly wind anomalies over SWC.Meanwhile,the ascending motion over the warm pool region diverges at upper levels with outflows converging aloft over SWC,which further induces compensating downward motion there.The combined effect of the above two remote forcings establishes a climatic background state unfavorable for precipitation over SWC at long time scales,thus constituting a crucial prerequisite for the superimposition of short-term precipitation anomalies to develop into super droughts.展开更多
This study investigates how English morphological awareness contributes to reading comprehension in beginner Chinese EFL learners.The research examines both derivational and compounding morphological awareness at mult...This study investigates how English morphological awareness contributes to reading comprehension in beginner Chinese EFL learners.The research examines both derivational and compounding morphological awareness at multiple levels(identification,discrimination,and manipulation)on English reading comprehension and explores whether their contributions are mediated by vocabulary knowledge.Data were collected from 71 Grade 9 students using various morphological awareness tasks,a vocabulary test,and a reading comprehension assessment.Mixed-effects regression and mediation analyses revealed that all components of morphological awareness,except derivational identification,significantly contributed to reading comprehension.Derivational manipulation was found to have both direct and indirect effects on reading comprehension,partially mediated by vocabulary knowledge.In contrast,compounding awareness influenced reading comprehension primarily through its effect on vocabulary.These findings provide a more nuanced understanding of how different facets of morphological awareness impact reading comprehension in EFL contexts,offering valuable insights for vocabulary and reading instruction.展开更多
This study aims to investigate the antioxidant activity of Tibetan gentian(Gentiana spp.)extract and its essence when compounded with a facial mask matrix.It also evaluates the efficacy of facial masks containing gent...This study aims to investigate the antioxidant activity of Tibetan gentian(Gentiana spp.)extract and its essence when compounded with a facial mask matrix.It also evaluates the efficacy of facial masks containing gentian extract on sensitive facial skin and analyzes the comprehensive performance of the mask.A total of 90 patients with facial sensitive skin,enrolled between October 2022 and December 2024,were randomly assigned to either a control group or an observation group,with 45 patients in each.The control group used standard facial masks,while the observation group used masks containing gentian extract.Both groups underwent a 4-week intervention.The effi cacy,lactic acid stinging test indicators,and skin physiological function parameters were compared between the two groups.Results showed that the overall eff ectiveness rate in the observation group reached 93.26%,signifi cantly higher than 71.20%in the control group(P<0.05).After the intervention,both groups showed notable improvements compared to baseline in lactic acid stinging test scores and physiological skin indicators.Specifi cally,the observation group had signifi cantly lower stinging scores and a longer latency before the onset of stinging compared to the control group.Moreover,the skin pH values were lower,while sebum levels and stratum corneum hydration were higher than those in the control group(P<0.05).No serious adverse events occurred in either group.These fi ndings suggest that facial masks containing gentian extract eff ectively alleviate symptoms of sensitive facial skin,enhance skin barrier function and tolerance,and are safe for use.展开更多
Initial success has been achieved in Hong Kong in controlling primary air pollutants,but ambient ozone levels kept increasing during the past three decades.Volatile organic compounds(VOCs)are important for mitigating ...Initial success has been achieved in Hong Kong in controlling primary air pollutants,but ambient ozone levels kept increasing during the past three decades.Volatile organic compounds(VOCs)are important for mitigating ozone pollution as its major precursors.This study analyzed VOC characteristics of roadside,suburban,and rural sites in Hong Kong to investigate their compositions,concentrations,and source contributions.Herewe showthat the TVOC concentrations were 23.05±13.24,12.68±15.36,and 5.16±5.48 ppbv for roadside,suburban,and rural sites between May 2015 to June 2019,respectively.By using Positive Matrix Factorization(PMF)model,six sources were identified at the roadside site over five years:Liquefied petroleum gas(LPG)usage(33%–46%),gasoline evaporation(8%–31%),aged air mass(11%–28%),gasoline exhaust(5%–16%),diesel exhaust(2%–16%)and fuel filling(75–9%).Similarly,six sources were distinguished at the suburban site,including LPG usage(30%–33%),solvent usage(20%–26%),diesel exhaust(14%–26%),gasoline evaporation(8%–16%),aged air mass(4%–11%),and biogenic emissions(2%–5%).At the rural site,four sources were identified,including aged airmass(33%–51%),solvent usage(25%–30%),vehicular emissions(11%–28%),and biogenic emissions(6%–12%).The analysis further revealed that fuel filling and LPG usage were the primary contributors to OFP and OH reactivity at the roadside site,while solvent usage and biogenic emissions accounted for almost half of OFP and OH reactivity at the suburban and rural sites,respectively.These findings highlight the importance of identifying and characterizing VOC sources at different sites to help policymakers develop targeted measures for pollution mitigation in specific areas.展开更多
VOCs(Volatile organic compounds)exert a vital role in ozone and secondary organic aerosol production,necessitating investigations into their concentration,chemical characteristics,and source apportionment for the effe...VOCs(Volatile organic compounds)exert a vital role in ozone and secondary organic aerosol production,necessitating investigations into their concentration,chemical characteristics,and source apportionment for the effective implementation of measures aimed at preventing and controlling atmospheric pollution.FromJuly to October 2020,onlinemonitoringwas conducted in the main urban area of Shijiazhuang to collect data on VOCs and analyze their concentrations and reactivity.Additionally,the PMF(positive matrix factorization)method was utilized to identify the VOCs sources.Results indicated that the TVOCs(total VOCs)concentration was(96.7±63.4μg/m^3),with alkanes exhibiting the highest concentration of(36.1±26.4μg/m^3),followed by OVOCs(16.4±14.4μg/m^3).The key active components were alkenes and aromatics,among which xylene,propylene,toluene,propionaldehyde,acetaldehyde,ethylene,and styrene played crucial roles as reactive species.The sources derived from PMF analysis encompassed vehicle emissions,solvent and coating sources,combustion sources,industrial emissions sources,as well as plant sources,the contribution of which were 37.80%,27.93%,16.57%,15.24%,and 2.46%,respectively.Hence,reducing vehicular exhaust emissions and encouraging neighboring industries to adopt low-volatile organic solvents and coatings should be prioritized to mitigate VOCs levels.展开更多
Furniture is identified as a vital volatile organic compound(VOC)emission source in the indoor environment.Leather has become the most common raw and auxiliary fabric material for upholstered furniture,particularly wi...Furniture is identified as a vital volatile organic compound(VOC)emission source in the indoor environment.Leather has become the most common raw and auxiliary fabric material for upholstered furniture,particularly with extensive consumption in sofas,due to its abundant resources and efficient functions.Despite being widely traded across the world,little research has been conducted on the VOCs released by leathermaterials and their health risk assessment in the indoor environment.Accordingly,this study investigated the VOC emissions of leather with different grades and the health risk of the inhalation exposure.Based on the ultra-fast gas phase electronic nose(EN)and GC-FID/Qtof,the substantial emissions of aliphatic aldehyde ketones(Aks),particularly hexanal,appear to be the cause of off-flavor in medium and low grade(MG and LG)sofa leathers.The health risk assessment indicated that leather materials barely pose non-carcinogenic and carcinogenic effects to residents.Given the abundance of VOC sources and the accumulation of health risks in the indoor environment,more stringent specifications concerning qualitative and quantitative content should be extended to provide VOC treatment basic for the manufacturing industry and obtain better indoor air quality.展开更多
Assessing the impact of anthropogenic volatile organic compounds(VOCs)on ozone(O_(3))formation is vital for themanagement of emission reduction and pollution control.Continuousmeasurement of O_(3)and the major precurs...Assessing the impact of anthropogenic volatile organic compounds(VOCs)on ozone(O_(3))formation is vital for themanagement of emission reduction and pollution control.Continuousmeasurement of O_(3)and the major precursorswas conducted in a typical light industrial city in the YRD region from 1 May to 25 July in 2021.Alkanes were the most abundant VOC group,contributing to 55.0%of TVOCs concentration(56.43±21.10 ppb).OVOCs,aromatics,halides,alkenes,and alkynes contributed 18.7%,9.6%,9.3%,5.2%and 1.9%,respectively.The observational site shifted from a typical VOC control regime to a mixed regime from May to July,which can be explained by the significant increase of RO_(x)production,resulting in the transition of environment from NOx saturation to radical saturation with respect to O_(3)production.The optimal O_(3)control strategy should be dynamically changed depending on the transition of control regime.Under NOx saturation condition,minimizing the proportion of NOx in reduction could lead to better achievement of O_(3)alleviation.Under mixed control regime,the cut percentage gets the top priority for the effectiveness of O_(3)control.Five VOCs sources were identified:temperature dependent source(28.1%),vehicular exhausts(19.9%),petrochemical industries(7.2%),solvent&gasoline usage(32.3%)and manufacturing industries(12.6%).The increase of temperature and radiation would enhance the evaporation related VOC emissions,resulting in the increase of VOC concentration and the change of RO_(x)circulation.Our results highlight determination of the optimal control strategies for O_(3)pollution in a typical YRD industrial city.展开更多
Edible oils derived from aquatic products are rich in lipids beneficial to human health.However,the volatile flavor characteristics of flesh oil and liver oil from Doederleinia berycoides remain unclear.In this study,...Edible oils derived from aquatic products are rich in lipids beneficial to human health.However,the volatile flavor characteristics of flesh oil and liver oil from Doederleinia berycoides remain unclear.In this study,flesh oil and liver oil were extracted from Doederleinia berycoides,revealing different fatty acid compositions and contents.Lipidomics analysis identified a total of 124 differential lipids between the flesh oil and liver oil,including 42 glycerophospholipids(GPs),33 glycerolipids(GLs),23 free fatty acids(FAs),13 sphingolipids(SPs),10 sterols(STs),and 3 prenol lipids(PRs).Analysis using HS-GC-IMS identified 12 key volatile compounds that significantly contributed to the distinct volatile flavors of the flesh and liver oils.The volatile flavors originated from these volatile compounds,which had different Relative Odor Activity Values(ROAVs).Further results from HSSPME-GC-MS showed that the volatile flavors of the flesh oil and liver oil were respectively attributed to 64 and 35 volatile compounds,each with unique key volatile compounds exhibiting different ROAVs.There were significant positive or negative correlations between 18 key differential lipids and 24 volatile compounds in both flesh oil and liver oil.Therefore,the complex lipid profiles are responsible for the unique volatile flavors of flesh oil and liver oil,and the differential lipids play a central role in their volatile flavor formation.These findings provide a foundation for understanding the volatile flavor differences in fish oils and hold promise for further exploration of the molecular mechanisms underlying oil volatile flavors.展开更多
The organic compound composition ofwastewater,serves as a crucial indicator for the operational performance of activated sludge processes and has a major influence on the development of filamentous bulking in activate...The organic compound composition ofwastewater,serves as a crucial indicator for the operational performance of activated sludge processes and has a major influence on the development of filamentous bulking in activated sludge.This study focused on the impact of typical soluble and slowly-biodegradable organic compounds,investigating the pathways through which these substrates affect the occurrence of filamentous bulking in systems operated under both high-and low-oxygen conditions.Results showed that slowly-biodegradable organic compounds lead to a concentrated distribution of microorganisms within flocs,with inward growth of filamentous bacteria.Both Tween-80 and granular starch treated systems exhibited a significant increase in protein content.The glucose system,utilizing soluble substrates,exhibited a markedly higher total polysaccharide content.Microbial communities in the Tween-80 and granular starch treated systems were characterized by a higher abundance of bacteria known to enhance sludge flocculation and settling,such as Competibacter,Xanthomonadaceae and Zoogloea.These findings are of high significance for controlling the operational performance and stability of activated sludge systems,deepening our understanding and providing a novel perspective for the improvement of wastewater treatment processes.展开更多
基金Supported by the National High Technology Research and Development Program of China(No.2002AA333040)the Special Funds of Science and Technology Bureau of Harbin for Hi-Tech Research,China(No.2007AA4BG140)
文摘Ultrafine full-vulcanized polybutadiene rubber（UFBR） with particle sizes of ca.50―100 nm were used for modifying mechanical and processing performances of polypropylene（PP） with PP-g-maleic anhydride（PP-g-MA） as a compatibilizer for enhancing the interfacial adhesion between the two components.The morphology,dynamical rheology response and mechanical properties of the blends were characterized by means of SEM,rheometer and tensile test,respectively.The results show that the ternary PP/UFBR blends compatibilized with PP-g-MA possess rheological behaviors like highly branched PP,while no obvious strain hardening is observed in its control binary PP/UFBR blends,a low level of PP-g-MA in PP/UFBR blends can even endow the material with rheological characteristics of high melt strength materials like highly branched PP.The enhancement interfacial interaction between the UFBR particles and PP matrix accounting for the rheological behavior of compatibilized blends and effectiveness of PP-g-MA were proposed and proved.
文摘An anomalous phase containing clays and humic acid was found while extraction humic acid from samples of weathering crust of REE-bearing granites by using 0.1 mol/L NaOH solution.Studied by chemical separation experiments,column chromatography,ion-exchange chromatography,infrared spectrum.fluorescence spectrum,polarimicroscopic testing and elemental determination by ultraviolet-visible spectrometer and atomic absorption spectrometer.it was proved to be a compound of humic acid and clays which are connected in the form of bridge by heteronuclearpolynuclear complexing ions formed by cations of RE￣(5+),Al￣(3+).Fe￣(3+) etc.The compounding pattern was further proved by the experiment for compounding humic acid,REE and kaolinite.
基金Project(2013GZX0147-3) supported by the Natural Science Foundation of Sichuan Province,China
文摘To improve the quality of ultrasonic elastography, by taking the advantage of code excitation and frequency compounding, a transmitting-side multi-frequency with coded excitation for elastography （TFCCE） was proposed. TFCCE adopts the chirp signal excitation scheme and strikes a balance in the selection of sub-signal bandwidth, the bandwidth overlap and the number of sub-strain image based on theoretical derivation, so as to further improve the quality of elastic image. Experiments have proved that, compared with the other optimizing methods, the elastographyic signal-to-noise ratio（Re-SN） and contrast-to-noise ratio（Re-CN） are improved significantly with different echo signal-to-noise ratios （ReSN） and attenuation coefficients. When ReSN is 50 dB, compared with short pulse, Rc-SN and Re-CN obtained by TFCCE increase by 53% and 143%, respectively. Moreover, in a deeper investigation （85-95 mm）, the image has lower strain noise and clear details. When the attenuation coefficient is in the range of 0-1 dB/（cm.MHz）, Re-SN and Re-CN obtained by TFCCE can be kept in moderate ranges of 5〈Re-SN〈6.8 and 11.4〈Re-CN〈15.2, respectively. In particular, for higher tissue attenuation, the basic image quality cannot be ensured with short pulse excitation, while mediocre quality strain figure can be obtained by TFCCE. Therefore, the TFCCE technology can effectively improve the elastography quality and can be applied to ultrasonic clinical trials.
文摘In order to observe the effects of the ground and intact Zhi Zi (Fructus Gardeniae) and different combinations of the ingredients and refined single Chinese drug granules in Yin Chen Hao Decoction compound prescription on the contents of gardenoside (an effective component of the prescription), the contents of gardenoside were determined with reversed phase high performance liquid chromatography (HPLC), with acetonitrile-water (15:85) as mobile phase, at wave length 238nm. The results indicated that the gardenoside-decocted-out rates in the decoctions prepared by different combinations of the ingredients with the ground Zhi Zi (Fructus Gardeniae) all were higher significantly than those in the decoction with intact Zhi Zi (Fructus Gardeniae), and generally, different combinations of the ingredients in the decoction had only little effect on the gardenoside-decocted-out rate.
文摘Aiming at the problem of runner unbalance in the compounding cavity of the upper and lower cover of the correction tape box, the plastic injection analysis software Moldflow was used to optimize runner balance. First, the 3D modeling software Proe was used to establish the geometric model of the upper and lower cover of the correction tape box, and introduced into the plastic injection analysis software Moldflow. Secondly, the upper and the lower cover of the correction tape box were meshed and the initial gating system was designed in Moldflow. Filling analysis of the initial scheme of the correction tape box combined cavity showed that the runner of the melt was not balanced in the mold cavity. Finally, the runner balance optimization analysis of the cavities was carried out. Through optimization, the time unbalance rate of the melt in the mold cavity decreased from 28.6% to 0.7%, the pressure unbalance rate decreased from 42.0% to 4.2%, and the pressure distribution in the cavity was more uniform in the whole injection process.
文摘This study aims to find the compound registers that are used among the Farm-Centre cell-phone marketers,analyse their compounding morphological structures,and explain the meaning they convey.The Farm-Centre Cell-phone Market is located in Kano metropolis,the largest city of Northern Nigeria.The study employs an ethnographic method of data collection and adopts Abubakar(2000)as a model of approach when analysing the structures of the compound registers.It is found that the registers have the following six morphological compound structures:(i)Genitive-based compounds[LG+N]N,(ii)Noun-based compounds[N+GL+N]N,(iii)Adjective-based compounds[Adj+N]N,(iv)Diminutive-based compounds[Dim+N]N,(v)Particle dà‘with’compounds[dà+N]N,(vi)Verb-based compounds[V+VN/Prep]V.Moreover,the registers are so special among the marketers because they convey meanings that are irrelevant to the conventional meanings known by the general speakers of the Hausa language.
文摘In English language,affixation is a significant way of forming new words,This essay intends to explore the concepts of two fundamental ways of forming new words,namely,derivation and compounding.They are different in a lot of cases,yet,it is also argued that there is a clear dividing line between compounding and derivation.
基金supported by the National Natural Science Foundation of China(Grant Nos.42175041&42230605)the International Partnership Program of Chinese Academy of Sciences for Future Network(Grant No.060GJHZ2022104FN)+1 种基金the Youth Program of the Institute of Atmospheric Physics,Chinese Academy of Sciences during the 14th Five-Year Plan Periodthe Open Research Fund of Heavy Rain and Drought-Flood Disasters in Plateau and Basin Key Laboratory of Sichuan Province(Grant No.SZKT202204)。
文摘In recent decades,Southwest China(SWC)has suffered from frequent super droughts,leading to severe economic losses and ecological degradation.This study investigates the characteristics of super droughts in SWC during 1961-2022,reveals the compounding effect of multiscalar anomalies,and explores the plausible atmospheric circulation mechanisms responsible.The nature of super drought is a compound drought caused by the superposition of extreme drought events across multiple time scales.By contrasting the typical drought cases in 2006 and 2022,the decisive role of multiscalar drought compounding is confirmed.Based on the Comprehensive Multiscalar Index(CMI),multiple super drought events in SWC were identified to be temporally clustered during 2006-2014.Among them,the decadal background of enhanced evaporation and precipitation deficit at long time scales is a necessary condition for shaping the overall pattern of super droughts,while the precipitation and evaporation anomalies at short time scales trigger the outbreak of super droughts,determining the exact timing of occurrence.These events include August-September 2006,November 2009 to May 2010,July-October 2011,April-May 2012,January-April 2013,etc.Statistical results suggest that the contribution of superposed precipitation anomalies to super drought is 2.4 times that of evaporation.As regards the circulation mechanisms affecting multiscalar precipitation,the anomalous spatial patterns at short-term and long-term scales are similar,featuring the cyclonic circulation over the South China Sea and the northeasterly wind anomalies together with the subsidence center over SWC.During 2006-2014,the possible causes for the cross-seasonal persistent precipitation reduction in SWC are the extreme negative phase of the Pacific Decadal Oscillation(PDO)in the North Pacific as well as the pronounced warming of the warm pool in the western Pacific.The key dynamic processes are outlined as follows.On the one hand,the negative PDO phase generates anomalous anticyclonic circulation in the North Pacific,with the northeasterly winds on its southwest flank extending to Southeast Asia,hindering moisture transport into SWC.On the other hand,the warming of the warm pool excites anomalous cyclonic circulation to its northwest,also giving rise to northeasterly wind anomalies over SWC.Meanwhile,the ascending motion over the warm pool region diverges at upper levels with outflows converging aloft over SWC,which further induces compensating downward motion there.The combined effect of the above two remote forcings establishes a climatic background state unfavorable for precipitation over SWC at long time scales,thus constituting a crucial prerequisite for the superimposition of short-term precipitation anomalies to develop into super droughts.
文摘This study investigates how English morphological awareness contributes to reading comprehension in beginner Chinese EFL learners.The research examines both derivational and compounding morphological awareness at multiple levels(identification,discrimination,and manipulation)on English reading comprehension and explores whether their contributions are mediated by vocabulary knowledge.Data were collected from 71 Grade 9 students using various morphological awareness tasks,a vocabulary test,and a reading comprehension assessment.Mixed-effects regression and mediation analyses revealed that all components of morphological awareness,except derivational identification,significantly contributed to reading comprehension.Derivational manipulation was found to have both direct and indirect effects on reading comprehension,partially mediated by vocabulary knowledge.In contrast,compounding awareness influenced reading comprehension primarily through its effect on vocabulary.These findings provide a more nuanced understanding of how different facets of morphological awareness impact reading comprehension in EFL contexts,offering valuable insights for vocabulary and reading instruction.
文摘This study aims to investigate the antioxidant activity of Tibetan gentian(Gentiana spp.)extract and its essence when compounded with a facial mask matrix.It also evaluates the efficacy of facial masks containing gentian extract on sensitive facial skin and analyzes the comprehensive performance of the mask.A total of 90 patients with facial sensitive skin,enrolled between October 2022 and December 2024,were randomly assigned to either a control group or an observation group,with 45 patients in each.The control group used standard facial masks,while the observation group used masks containing gentian extract.Both groups underwent a 4-week intervention.The effi cacy,lactic acid stinging test indicators,and skin physiological function parameters were compared between the two groups.Results showed that the overall eff ectiveness rate in the observation group reached 93.26%,signifi cantly higher than 71.20%in the control group(P<0.05).After the intervention,both groups showed notable improvements compared to baseline in lactic acid stinging test scores and physiological skin indicators.Specifi cally,the observation group had signifi cantly lower stinging scores and a longer latency before the onset of stinging compared to the control group.Moreover,the skin pH values were lower,while sebum levels and stratum corneum hydration were higher than those in the control group(P<0.05).No serious adverse events occurred in either group.These fi ndings suggest that facial masks containing gentian extract eff ectively alleviate symptoms of sensitive facial skin,enhance skin barrier function and tolerance,and are safe for use.
基金supported by Hong Kong Environment Protection Department(Quotation Ref.18-06532)Hong Kong Innovation and Technology Fund(ITS/193/20FP)Hong Kong Research Grants Council(No.26304921).
文摘Initial success has been achieved in Hong Kong in controlling primary air pollutants,but ambient ozone levels kept increasing during the past three decades.Volatile organic compounds(VOCs)are important for mitigating ozone pollution as its major precursors.This study analyzed VOC characteristics of roadside,suburban,and rural sites in Hong Kong to investigate their compositions,concentrations,and source contributions.Herewe showthat the TVOC concentrations were 23.05±13.24,12.68±15.36,and 5.16±5.48 ppbv for roadside,suburban,and rural sites between May 2015 to June 2019,respectively.By using Positive Matrix Factorization(PMF)model,six sources were identified at the roadside site over five years:Liquefied petroleum gas(LPG)usage(33%–46%),gasoline evaporation(8%–31%),aged air mass(11%–28%),gasoline exhaust(5%–16%),diesel exhaust(2%–16%)and fuel filling(75–9%).Similarly,six sources were distinguished at the suburban site,including LPG usage(30%–33%),solvent usage(20%–26%),diesel exhaust(14%–26%),gasoline evaporation(8%–16%),aged air mass(4%–11%),and biogenic emissions(2%–5%).At the rural site,four sources were identified,including aged airmass(33%–51%),solvent usage(25%–30%),vehicular emissions(11%–28%),and biogenic emissions(6%–12%).The analysis further revealed that fuel filling and LPG usage were the primary contributors to OFP and OH reactivity at the roadside site,while solvent usage and biogenic emissions accounted for almost half of OFP and OH reactivity at the suburban and rural sites,respectively.These findings highlight the importance of identifying and characterizing VOC sources at different sites to help policymakers develop targeted measures for pollution mitigation in specific areas.
基金supported by the Natural Science Foundation of Hebei Province(Nos.D2019106042,D2020304038,and D2021106002)the National Natural Science Foundation of China(No.22276099)+1 种基金the State Environmental Protection Key Laboratory of Formation and Prevention of Urban Air Pollution Complex(No.2021080544)the Environmental Monitoring Research Foundation of Jiangsu Province(No.2211).
文摘VOCs(Volatile organic compounds)exert a vital role in ozone and secondary organic aerosol production,necessitating investigations into their concentration,chemical characteristics,and source apportionment for the effective implementation of measures aimed at preventing and controlling atmospheric pollution.FromJuly to October 2020,onlinemonitoringwas conducted in the main urban area of Shijiazhuang to collect data on VOCs and analyze their concentrations and reactivity.Additionally,the PMF(positive matrix factorization)method was utilized to identify the VOCs sources.Results indicated that the TVOCs(total VOCs)concentration was(96.7±63.4μg/m^3),with alkanes exhibiting the highest concentration of(36.1±26.4μg/m^3),followed by OVOCs(16.4±14.4μg/m^3).The key active components were alkenes and aromatics,among which xylene,propylene,toluene,propionaldehyde,acetaldehyde,ethylene,and styrene played crucial roles as reactive species.The sources derived from PMF analysis encompassed vehicle emissions,solvent and coating sources,combustion sources,industrial emissions sources,as well as plant sources,the contribution of which were 37.80%,27.93%,16.57%,15.24%,and 2.46%,respectively.Hence,reducing vehicular exhaust emissions and encouraging neighboring industries to adopt low-volatile organic solvents and coatings should be prioritized to mitigate VOCs levels.
基金supported by the National Key Research and Development Program of China (No.2019YFC1904501).
文摘Furniture is identified as a vital volatile organic compound(VOC)emission source in the indoor environment.Leather has become the most common raw and auxiliary fabric material for upholstered furniture,particularly with extensive consumption in sofas,due to its abundant resources and efficient functions.Despite being widely traded across the world,little research has been conducted on the VOCs released by leathermaterials and their health risk assessment in the indoor environment.Accordingly,this study investigated the VOC emissions of leather with different grades and the health risk of the inhalation exposure.Based on the ultra-fast gas phase electronic nose(EN)and GC-FID/Qtof,the substantial emissions of aliphatic aldehyde ketones(Aks),particularly hexanal,appear to be the cause of off-flavor in medium and low grade(MG and LG)sofa leathers.The health risk assessment indicated that leather materials barely pose non-carcinogenic and carcinogenic effects to residents.Given the abundance of VOC sources and the accumulation of health risks in the indoor environment,more stringent specifications concerning qualitative and quantitative content should be extended to provide VOC treatment basic for the manufacturing industry and obtain better indoor air quality.
基金supported by the National Natural Science Foundation of China(Nos.42005086,91844301,and 41805100)the National Key Research and Development Programof China(No.2022YFC3703500)+2 种基金China Postdoctoral Science Foundation(No.2023M733028)the Key Research and Development Program of Zhejiang Province(Nos.2021C03165 and 2022C03084)the Ecological and Environmental Scientific Research and Achievement Promotion Project of Zhejiang Province(No.2020HT0048).
文摘Assessing the impact of anthropogenic volatile organic compounds(VOCs)on ozone(O_(3))formation is vital for themanagement of emission reduction and pollution control.Continuousmeasurement of O_(3)and the major precursorswas conducted in a typical light industrial city in the YRD region from 1 May to 25 July in 2021.Alkanes were the most abundant VOC group,contributing to 55.0%of TVOCs concentration(56.43±21.10 ppb).OVOCs,aromatics,halides,alkenes,and alkynes contributed 18.7%,9.6%,9.3%,5.2%and 1.9%,respectively.The observational site shifted from a typical VOC control regime to a mixed regime from May to July,which can be explained by the significant increase of RO_(x)production,resulting in the transition of environment from NOx saturation to radical saturation with respect to O_(3)production.The optimal O_(3)control strategy should be dynamically changed depending on the transition of control regime.Under NOx saturation condition,minimizing the proportion of NOx in reduction could lead to better achievement of O_(3)alleviation.Under mixed control regime,the cut percentage gets the top priority for the effectiveness of O_(3)control.Five VOCs sources were identified:temperature dependent source(28.1%),vehicular exhausts(19.9%),petrochemical industries(7.2%),solvent&gasoline usage(32.3%)and manufacturing industries(12.6%).The increase of temperature and radiation would enhance the evaporation related VOC emissions,resulting in the increase of VOC concentration and the change of RO_(x)circulation.Our results highlight determination of the optimal control strategies for O_(3)pollution in a typical YRD industrial city.
基金supported by the R&D Projects in Key Areas of Guangdong Province(2023B0202080003)the National Natural Science Foundation of China(32472272,32302135,32072291)+1 种基金“Pioneer”and“Leading Goose”R&D Program of Zhejiang(2023C02006)Youth S&T Talent Support Programme of Guangdong Provincial Association for Science and Technology(SKXRC202401)。
文摘Edible oils derived from aquatic products are rich in lipids beneficial to human health.However,the volatile flavor characteristics of flesh oil and liver oil from Doederleinia berycoides remain unclear.In this study,flesh oil and liver oil were extracted from Doederleinia berycoides,revealing different fatty acid compositions and contents.Lipidomics analysis identified a total of 124 differential lipids between the flesh oil and liver oil,including 42 glycerophospholipids(GPs),33 glycerolipids(GLs),23 free fatty acids(FAs),13 sphingolipids(SPs),10 sterols(STs),and 3 prenol lipids(PRs).Analysis using HS-GC-IMS identified 12 key volatile compounds that significantly contributed to the distinct volatile flavors of the flesh and liver oils.The volatile flavors originated from these volatile compounds,which had different Relative Odor Activity Values(ROAVs).Further results from HSSPME-GC-MS showed that the volatile flavors of the flesh oil and liver oil were respectively attributed to 64 and 35 volatile compounds,each with unique key volatile compounds exhibiting different ROAVs.There were significant positive or negative correlations between 18 key differential lipids and 24 volatile compounds in both flesh oil and liver oil.Therefore,the complex lipid profiles are responsible for the unique volatile flavors of flesh oil and liver oil,and the differential lipids play a central role in their volatile flavor formation.These findings provide a foundation for understanding the volatile flavor differences in fish oils and hold promise for further exploration of the molecular mechanisms underlying oil volatile flavors.
基金supported by the Opening Project of National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology,and the National Natural Science Foundation of China(No.52270017).
文摘The organic compound composition ofwastewater,serves as a crucial indicator for the operational performance of activated sludge processes and has a major influence on the development of filamentous bulking in activated sludge.This study focused on the impact of typical soluble and slowly-biodegradable organic compounds,investigating the pathways through which these substrates affect the occurrence of filamentous bulking in systems operated under both high-and low-oxygen conditions.Results showed that slowly-biodegradable organic compounds lead to a concentrated distribution of microorganisms within flocs,with inward growth of filamentous bacteria.Both Tween-80 and granular starch treated systems exhibited a significant increase in protein content.The glucose system,utilizing soluble substrates,exhibited a markedly higher total polysaccharide content.Microbial communities in the Tween-80 and granular starch treated systems were characterized by a higher abundance of bacteria known to enhance sludge flocculation and settling,such as Competibacter,Xanthomonadaceae and Zoogloea.These findings are of high significance for controlling the operational performance and stability of activated sludge systems,deepening our understanding and providing a novel perspective for the improvement of wastewater treatment processes.
