Gypsum was used as substrate,and silica gel was mixed into substrate at a certain mass ratio to prepare humidity-controlling composites;moreover,the moisture absorption and desorption properties of gypsum-based compos...Gypsum was used as substrate,and silica gel was mixed into substrate at a certain mass ratio to prepare humidity-controlling composites;moreover,the moisture absorption and desorption properties of gypsum-based composites were compared with adding different silica gel particle size and proportion.The morphological characteristics,the isothermal equilibrium moisture content curve,moisture absorption and desorption rate,moisture absorption and desorption stability,and humidity-conditioning performance were tested and analyzed.The experimental results show that,compared with pure-gypsum,the surface structure of the gypsum-based composites is relatively loose,the quantity,density and aperture of the pores in the structure increase.The absorption and desorption capacity increase along with the increase of silica gel particle size and silica gel proportion.When 3 mm silica gel particle size is added with a mass ratio of 40%,the maximum equilibrium moisture content of humidity-controlling composites is 0.161 g/g at 98% relative humidity(RH),3.22 times that of pure-gypsum.The moisture absorption and desorption rates are increased,the equilibrium moisture absorption and desorption rates are 2.68 times and 1.61 times that of pure-gypsum at 58.5% RH,respectively.The gypsum-based composites have a good stability,which has better timely response to dynamic humidity changes and can effectively regulate indoor humidity under natural conditions.展开更多
This study aims to quantify the susceptibility of granular materials used in pavements to changes in moisture content and propose a correlation model to incorporate this susceptibility into seasonal analyses.The fines...This study aims to quantify the susceptibility of granular materials used in pavements to changes in moisture content and propose a correlation model to incorporate this susceptibility into seasonal analyses.The fines content and the percentage of fractured coarse aggregates were identified as direct indicators of the resilient modulus susceptibility to changes in water content.The results showed that the percentage of fractured coarse aggregates particles(FR)has a more significant impact on the resilient modulus(Er)of crushed granular materials used in pavement construction than the combined indicator of the fines content and sample volumetrics(nf).Crushed granular materials with a higher percentage of fractured coarse aggregates are relatively insensitive to changes in the degree of saturation,but become more sensitive as the fine fraction porosity decreases.An adjusted model was proposed based on the existing formulation,but considers a complex parameter to describe and adjust the sensitivity of base granular materials to variations in moisture content with respect to fabrication charac-teristics,fines content and volumetric properties.The model shows that the variation of Er values is below10%for fully crushed granular materials.However,it reaches approximately±12%for materials with 75%of crushed coarse aggregates andþ40%and-25%for materials with FR=50%.This model could help select good ag-gregates characteristics and adjust grain-size distribution for environments where significant moisture content variations can occur in the pavement system,such as in the Province of Quebec(Canada).As it is based on pa-rameters that can be easily determined or estimated,it also represents a valuable tool for detailed design and analysis that can consider material characteristics.展开更多
Human metabolite moisture detection is important in health monitoring and non-invasive diagnosis.However,ultra-sensitive quantitative extraction of respiration information in real-time remains a great challenge.Herein...Human metabolite moisture detection is important in health monitoring and non-invasive diagnosis.However,ultra-sensitive quantitative extraction of respiration information in real-time remains a great challenge.Herein,chemiresistors based on imine-linked covalent organic framework(COF)films with dual-active sites are fabricated to address this issue,which demonstrates an amplified humidity-sensing signal performance.By regulation of monomers and functional groups,these COF films can be pre-engineered to achieve high response,wide detection range,fast response,and recovery time.Under the condition of relative humidity ranging from 13 to 98%,the COFTAPB-DHTA film-based humidity sensor exhibits outstanding humidity sensing perfor-mance with an expanded response value of 390 times.Furthermore,the response values of the COF film-based sensor are highly linear to the relative humidity in the range below 60%,reflecting a quantitative sensing mechanism at the molecular level.Based on the dual-site adsorption of the(-C=N-)and(C-N)stretching vibrations,the revers-ible tautomerism induced by hydrogen bonding with water molecules is demonstrated to be the main intrinsic mechanism for this effective humidity detection.In addition,the synthesized COF films can be further exploited to effectively detect human nasal and oral breathing as well as fabric permeability,which will inspire novel designs for effective humidity-detection devices.展开更多
Humidity can affect the attenuation of MEA(membrane electrode assembly), however, the relationship between humidity and MEA decays is complex and ambiguous in realistic application. Herein, we design a simulating auto...Humidity can affect the attenuation of MEA(membrane electrode assembly), however, the relationship between humidity and MEA decays is complex and ambiguous in realistic application. Herein, we design a simulating automotive protocol, performed on five single fuel cells under RH(relative humidity) 100%,RH 80%, RH 64%, and RH 40%, RH 10%, respectively, to study the relationship of MEA decays and humidity and suggest optimized humidity range to extend the durability. With the electrochemical impedance spectroscopy, cyclic voltammetry, X-ray fluorescence, X-ray diffraction, transmission electron microscope, X-ray photoelectron spectroscopy, the four degradation mechanisms about catalyst layer, including Pt dissolution, Pt coarsening, carbon corrosion and ionomer degradation, are observed. Pt coarsening and carbon corrosion are accelerated by higher water content at high humidity. Ionomer degradation and Pt dissolution are enhanced in low humidity. With the linear sweep voltammetry, ion chromatography,nuclear magnetic resonance, tensile test and scan electron microscope, chemical and mechanical degradation in proton exchange membrane are all observed in these five fuels. Chemical degradation, characterized by membrane thinning and more fluoride loss, occurred markedly in RH 10%. Mechanical degradation, characterized by the non-uniformity thickness and bad mechanical properties, is more pronounced in RH 100%, RH 80%, RH 64%. These two degradations are in a moderate level in RH 40%. The research suggests that the RH range from 64% to 40% is conductive to mitigate the degradation of MEAs operated in automotive applications.展开更多
Flexible and wearable humidity sensors play a vital role in daily point-of-care diagnosis and noncontact human-machine interactions.However,achieving a facile and high-speed fabrication approach to realizing flexible ...Flexible and wearable humidity sensors play a vital role in daily point-of-care diagnosis and noncontact human-machine interactions.However,achieving a facile and high-speed fabrication approach to realizing flexible humidity sensors remains a challenge.In this work,a wearable capacitive-type Ga_(2)O_(3)/liquid metal-based humidity sensor is demonstrated by a one-step laser direct writing technique.Owing to the photothermal effect of laser,the Ga_(2)O_(3)-wrapped liquid metal particles can be selectively sintered and converted from insulative to conductive traces with a resistivity of 0.19Ω·cm,while the untreated regions serve as active sensing layers in response to moisture changes.Under 95%relative humidity,the humidity sensor displays a highly stable performance along with rapid response and recover time.Utilizing these superior properties,the Ga_(2)O_(3)/liquid metal-based humidity sensor is able to monitor human respiration rate,as well as skin moisture of the palm under different physiological states for healthcare monitoring.展开更多
Breathing is an inherent human activity;however,the composition of the air we inhale and gas exhale remains unknown to us.To address this,wearable vapor sensors can help people monitor air composition in real time to ...Breathing is an inherent human activity;however,the composition of the air we inhale and gas exhale remains unknown to us.To address this,wearable vapor sensors can help people monitor air composition in real time to avoid underlying risks,and for the early detection and treatment of diseases for home healthcare.Hydrogels with three-dimensional polymer networks and large amounts of water molecules are naturally flexible and stretchable.Functionalized hydrogels are intrinsically conductive,self-healing,self-adhesive,biocompatible,and room-temperature sensitive.Compared with traditional rigid vapor sensors,hydrogel-based gas and humidity sensors can directly fit human skin or clothing,and are more suitable for real-time monitoring of personal health and safety.In this review,current studies on hydrogel-based vapor sensors are investigated.The required properties and optimization methods of wearable hydrogel-based sensors are introduced.Subsequently,existing reports on the response mechanisms of hydrogel-based gas and humidity sensors are summarized.Related works on hydrogel-based vapor sensors for their application in personal health and safety monitoring are presented.Moreover,the potential of hydrogels in the field of vapor sensing is elucidated.Finally,the current research status,challenges,and future trends of hydrogel gas/humidity sensing are discussed.展开更多
The environment significantly impacts the interaction between plants and pathogens,thus remarkably affecting crop disease occurrence.However,the detailed combined mechanisms of temperature and humidity influencing thi...The environment significantly impacts the interaction between plants and pathogens,thus remarkably affecting crop disease occurrence.However,the detailed combined mechanisms of temperature and humidity influencing this interaction remain unclear.In this study,the interaction between tomato and Botrytis cinerea in various temperature and humidity conditions was analyzed by histological observation and a dual RNA-seq approach.Results showed that low humidity was not favorable for mycelial growth,resulting in infection failure.Both high and low temperatures at high humidity successfully inhibited pathogenic infection and disease incidence in the tomato plants,thus enhancing their resistance to B.cinerea.The high temperature and high humidity(HH)treatment induced the upregulation of light reaction genes,increased the net photosynthetic rate,and expanded the chloroplast morphology of infected tomatoes.The HH treatment also inhibited the expression of cell cycle-related genes of B.cinerea,interfered with conidial germination andmycelial growth,and damagedmycelial cell structure.Lowtemperature and high humidity(LH)treatment induced the expression of cell wall modification genes and remodeled the cell wall morphology of tomatoes in response to B.cinerea.In addition,the downregulated fungal catabolic genes and the abnormal increase in electron density ofmycelial cells under LH treatment subsequently reduced the infection ability of B.cinerea.These results further explain the coupled effects of temperature and humidity on plant defenses and pathogen virulence,and provide a potential means to control gray mold.展开更多
Capacitive humidity sensors were made of nanometer barium titanate.The pellets were prepared under different pressures between 3920N to 7850N force.The capacitance changes in three orders of magnitude in the relative ...Capacitive humidity sensors were made of nanometer barium titanate.The pellets were prepared under different pressures between 3920N to 7850N force.The capacitance changes in three orders of magnitude in the relative humidity range of 10%～98%,indicating high humidity sensitivity of the sensors.At a certain measuring frequency,the capacitance of the sensors increases as increasing of the preparation pressure,while the sensitivity of the sensors basically remains the same.The frequencies corresponding to the peaks of the dielectric loss of the sensors move to the higher frequency direction as increasing of the relative humidity.At a certain humidity,the frequencies corresponding to the peaks of the dielectric loss move to the higher frequency direction as increasing of the preparation pressure.展开更多
The vertical distribution of vegetation types along an elevational gradient in mountain areas largely depends on the elevational changes in air temperature and humidity. In this study, we presented the seasonal and di...The vertical distribution of vegetation types along an elevational gradient in mountain areas largely depends on the elevational changes in air temperature and humidity. In this study, we presented the seasonal and diurnal variations in the elevational gradients of air temperature and humidity on the southern and northern slopes in the middle Tianshan Mountain Range using data collected throughout the year via HOBO data loggers. The measurements were conducted at 12 different elevations from 1548 to 3277 m from September 2004 to August 2005. The results showed that the annual mean air temperature decreased along the elevational gradients with temperature lapse rates of(0.71±0.20)°C/100 m and(0.59±0.05)°C/100 m on the northern and southern slopes, respectively. The annual mean absolute humidity significantly decreased with increasing elevation on the northern slope but showed no significant trend on the southern slope. The annual mean relative humidity did not show a significant trend on the northern slope but increased with increasing elevation on the southern slope. The mean air temperature lapse rate exhibited significant seasonal variation, which is steeper insummer and shallower in winter, and this value varied between 0.37°C/100 m and 0.75°C/100 m on the southern slope and between 0.30°C/100 m and 1.02°C/100 m on the northern slope. The mean absolute and relative humidity also exhibited significant seasonal variations on both slopes, with the maximum occurring in summer and the minimum occurring in winter or spring. The monthly diurnal range of air temperature on both slopes was higher in spring than in winter. The annual range of air temperature on the southern slope was higher than that on the northern slope. Our results suggest that significant spatiotemporal variations in humidity and temperature lapse rate are useful when analyzing the relationships between species range sizes and climate in mountain areas.展开更多
The development and character of compound temperature-humidity sensor were discussed in this study.The design of sampling,control and output unit of temperature-humidity sensor as well as their manufacture method and ...The development and character of compound temperature-humidity sensor were discussed in this study.The design of sampling,control and output unit of temperature-humidity sensor as well as their manufacture method and character were studied in detail.The relationship between components of humidity resistance materials and negative temperature coefficient ( NTC) thermistor materials in sampling unit of compound sensor and character of electrical resistance and temperature was obtained.Couples of character curves of compound temperature-humidity sensor and data of materials of sampling unit were shown in this paper too.展开更多
An impedance type humidity sensor based on the polyacrylic emulsion containing magnesium chloride (MgCl_2) without chemical modification was investigated.The impedances of the sensor were measured from various relati...An impedance type humidity sensor based on the polyacrylic emulsion containing magnesium chloride (MgCl_2) without chemical modification was investigated.The impedances of the sensor were measured from various relative humidity in the frequency range between 0.1kHz and 100 kHz.The sensor has a good sensitivity from 60%RH to 90%RH.According to the experimental results,the response time is about 240 seconds in the adsorption process and 310 seconds in the desorption process.展开更多
This paper reports on the fabrication and sensing characteristics of Polyimide-based humidity sensor,based on that,a new integrated circuit of humidity measurement has been designed.It is a novel capacitive-type syste...This paper reports on the fabrication and sensing characteristics of Polyimide-based humidity sensor,based on that,a new integrated circuit of humidity measurement has been designed.It is a novel capacitive-type systems on a chip structure using the MEMS process.The results show that the new sensor presents sensing characteristics over a humidity range from 10%～70% RH at 20℃,and the sensor is able to fabricated together with ICs technology.The result shows that integration of humidity sensor with integrated circuit of humidity measurement is considerably easier when they are built in sensing groove.The appeal of a new structure like this brings the possibility of applications that would require the flexibility of simple screen printing.展开更多
Soluble Poly(propargyl benzoate) (PPBT) with (-conjugated structure was synthesized using a novel bis(triphenylphosphine)-bisacetylide palladium complex catalyst [Pd(PPh3)2(C(CCH2OOCPh)2] (PPB). An interdigital gold e...Soluble Poly(propargyl benzoate) (PPBT) with (-conjugated structure was synthesized using a novel bis(triphenylphosphine)-bisacetylide palladium complex catalyst [Pd(PPh3)2(C(CCH2OOCPh)2] (PPB). An interdigital gold electrode was covered by screen printing films of doped PPBT (DPPBT) to prepare a resistance-type humidity sensor, which exhibits electrical response towards relative humidity (RH%) variations in the range 11%-96%. PPBT shows promise as a new humidity-sensitive material.展开更多
Poly(p-diethynylbenzene) (PDEB) with improved solubility was synthesized using anovel catalyst bis(triphenylphosphine)bis(p-diethnylbenzene) nickel complex (Ni-C). A surfaceacoustic wave (SAW) delay line oscillator wa...Poly(p-diethynylbenzene) (PDEB) with improved solubility was synthesized using anovel catalyst bis(triphenylphosphine)bis(p-diethnylbenzene) nickel complex (Ni-C). A surfaceacoustic wave (SAW) delay line oscillator was covered by Langmuir-Blodgett (LB) films of re-sulting PDEB to prepare a humidity sensor, which was found to have high sensitivity and goodrepeatability. PDEB shows promise as a good humidity-sensitive material.展开更多
The effect of external roof shading on the spatial distribution of air temperature and relative humidity in a greenhouse(Tin and RHin) was evaluated under the arid climatic conditions of Riyadh City, Saudi Arabia. Two...The effect of external roof shading on the spatial distribution of air temperature and relative humidity in a greenhouse(Tin and RHin) was evaluated under the arid climatic conditions of Riyadh City, Saudi Arabia. Two identical, evaporatively-cooled, single-span greenhouses were used in the experiment. One greenhouse was externally shaded(Gs) using a movable black plastic net(30% transmissivity), and the other greenhouse was kept without shading(Gc). Strawberry plants were cultivated in both greenhouses. The results showed that the spatial distribution of the Tin and RHin was significantly affected by the outside solar radiation and evaporative cooling operation. The regression analysis showed that when the outside solar radiation intensity increased from 200 to 800 W m–2, the Tin increased by 4.5℃ in the Gc and 2℃in the Gs, while the RHin decreased by 15% in the Gc and 5% in the Gs, respectively. Compared with those in the Gc, more uniformity in the spatial distribution of the Tin and RHin was observed in the Gs. The difference between the maximum and minimum Tin of 6.4℃ and the RHin of 10% was lower in the Gs than those in the Gc during the early morning. Around 2℃ difference in the Tin was shown between the area closed to the exhausted fans and the area closed to the cooling pad with the external shading. In an evaporatively-cooled greenhouse in arid regions, the variation of the Tin and RHin in the vertical direction and along the sidewalls was much higher than that in the horizontal direction. The average variation of the Tin and RHin in the vertical direction was 5.2℃ and 10% in the Gc and 5.5℃ and 13% in the Gs, respectively. The external shading improved the spatial distribution of the Tin and RHin and improved the cooling efficiency of the evaporative cooling system by 12%, since the transmitted solar radiation and accumulated thermal energy in the greenhouse were significantly reduced.展开更多
Surface relative humidity(RH)is a key element for weather and climate monitoring and research.However,RH is not as commonly applied in studying climate change,partly because the observation series of RH are prone to i...Surface relative humidity(RH)is a key element for weather and climate monitoring and research.However,RH is not as commonly applied in studying climate change,partly because the observation series of RH are prone to inhomogeneous biases due to non-climate changes in the observation system.A homogenized dataset of daily RH series from 746 stations in Chinese mainland for the period 1960–2017,ChinaRHv1.0,has been developed.Most(685 or 91.82%of the total)station time series were inhomogeneous with one or more break points.The major breakpoints occurred in the early 2000s for many stations,especially in the humid and semi-humid zones,due to the implementation of automated observation across the country.The inhomogeneous biases in the early manual records before this change are positive relative to the recent automatic records,for most of the biased station series.There are more break points detected by using the MASH(Multiple Analysis of Series for Homogenization)method,with biases mainly around?0.5%and 0.5%.These inhomogeneous biases are adjusted with reference to the most recent observations for each station.Based on the adjusted observations,the regional mean RH series of China shows little long-term trend during 1960–2017[0.006%(10 yr)^?1],contrasting with a false decreasing trend[?0.414%(10 yr)?1]in the raw data.It is notable that ERA5 reanalysis data match closely with the interannual variations of the raw RH series in China,including the jump in the early 2000s,raising a caveat for its application in studying climate change in the region.展开更多
Generally, the function of vocalizations made by male anurans are to attract females or defend resources. Typically, males vocalize in choruses during one or more periods in a twenty-four-hour cycle, which varies, how...Generally, the function of vocalizations made by male anurans are to attract females or defend resources. Typically, males vocalize in choruses during one or more periods in a twenty-four-hour cycle, which varies, however, among species. Nevertheless, the causal factors influencing circadian variations of calling patterns in anuran species are not clear. In this study, male chorus vocalizations were monitored in the Emei music frog(Babina daunchina) for 17 consecutive days during the breeding season, while its habitat air temperature and relative humidity in the course of experiments were measured as well. The results revealed that the circadian calling patterns were characterized by two periods of peak vocalization, which were observed from 0500 h to 0700 h and from 1300 h to 2000 h, while the lowest activity period was found from 2100 h to 2200 h. Both calls/h and notes/h were positively correlated with air temperature and negatively with relative humidity. Overall, our data indicate that the Emei music frogs(B. daunchina) could regulate their vocal activities based on the changes of physical micro-environment(e. g., temperature or humidity) to maximize reproductive success.展开更多
Cemented paste backfill(CPB),a mixture of tailings,binder,and water,is widely and extensively used for the recovery of mineral resources,the prevention of ground subsidence,and the management of mine waste.When instal...Cemented paste backfill(CPB),a mixture of tailings,binder,and water,is widely and extensively used for the recovery of mineral resources,the prevention of ground subsidence,and the management of mine waste.When installed,the CPB is subjected to complex environmental conditions such as water content,temperature,and power,which have a significant impact on its efficiency.Thus,this study conducts a series of laboratory programs,including investigation of moisture,temperature,stress–strain relation,and microstructure to show the effect of curing humidity on the CPB behaviors.The results obtained indicate that ambient humidity can have a dramatic effect on CPB in terms of its macro performance of internal relative humidity,temperature and strength,as well as the micro expression.Typical examples of these effects on CPB include an increase in curing humidity,which favors binder hydration,and then an increase in hydration materials,temperature and peak stress in the CPB.The results obtained will lead to a better understanding of CPB’s responses to various environmental conditions.展开更多
As the depth of exploitation increases,studies on constitutive models of rock affected by temperature and humidity become very important.Based on the Nishihara model,a visco-elastic-plastic rock model was established ...As the depth of exploitation increases,studies on constitutive models of rock affected by temperature and humidity become very important.Based on the Nishihara model,a visco-elastic-plastic rock model was established by using the coefficients of thermal and humidity expansion,thermal viscosity attenuation,humid viscosity attenuation and acceleration rheology components.We used the definition of a controlled heat circle to explain the model.The results show that the behavior of rock,affected by temperature and humidity,is stable as a function of time when the stress is lower than the first yield stress σS1;the creep rate will increase due to the effect of temperature and humidity when the stress is greater than or equal to σS1;the creep rate will accelerate at an increasing rate when the stress is greater than or equal to the second yield stress σS2,which results in a failure of the roadway.The model derived in this study can completely describe visco-elastic-plastic characteristics and reflects the three stages of rock creep.展开更多
The cooling and humidifying effects of urban parks are an essential component of city ecosystems in terms of regulating microclimates or mitigating urban heat islands(UHIs).Air temperature and relative humidity are tw...The cooling and humidifying effects of urban parks are an essential component of city ecosystems in terms of regulating microclimates or mitigating urban heat islands(UHIs).Air temperature and relative humidity are two main factors of thermal environmental comfort and have a critical impact on the urban environmental quality of human settlements.We measured the 2-m height air temperature and relative humidity at the Beijing Olympic Park and a nearby building roof for more than 1 year to elucidate seasonal variations in air temperature and relative humidity,as well as to investigate the outdoor thermal comfort.The results showed that the lawn of the park could,on average,reduce the air temperature by(0.80±0.19)℃,and increase the relative humidity by(5.24±2.91)% relative to the values measured at the building roof during daytime.During the nighttime,the lawn of the park reduced the air temperature by(2.64±0.64)℃ and increased the relative humidity by(10.77±5.20)%.The park was cooler and more humid than surrounding building area,especially in night period(more pronounced cooling with 1.84℃).Additionally,the lawn of the park could improve outdoor thermal comfort through its cooling and humidifying effects.The level of thermal comfort in the park was higher than that around the building roof for a total of 11 days annually in which it was above one or more thermal comfort levels(average reduced human comfort index of 0.92)except during the winter.展开更多
基金Funded by the National Natural Science Foundation of China(No.51678254)。
文摘Gypsum was used as substrate,and silica gel was mixed into substrate at a certain mass ratio to prepare humidity-controlling composites;moreover,the moisture absorption and desorption properties of gypsum-based composites were compared with adding different silica gel particle size and proportion.The morphological characteristics,the isothermal equilibrium moisture content curve,moisture absorption and desorption rate,moisture absorption and desorption stability,and humidity-conditioning performance were tested and analyzed.The experimental results show that,compared with pure-gypsum,the surface structure of the gypsum-based composites is relatively loose,the quantity,density and aperture of the pores in the structure increase.The absorption and desorption capacity increase along with the increase of silica gel particle size and silica gel proportion.When 3 mm silica gel particle size is added with a mass ratio of 40%,the maximum equilibrium moisture content of humidity-controlling composites is 0.161 g/g at 98% relative humidity(RH),3.22 times that of pure-gypsum.The moisture absorption and desorption rates are increased,the equilibrium moisture absorption and desorption rates are 2.68 times and 1.61 times that of pure-gypsum at 58.5% RH,respectively.The gypsum-based composites have a good stability,which has better timely response to dynamic humidity changes and can effectively regulate indoor humidity under natural conditions.
文摘This study aims to quantify the susceptibility of granular materials used in pavements to changes in moisture content and propose a correlation model to incorporate this susceptibility into seasonal analyses.The fines content and the percentage of fractured coarse aggregates were identified as direct indicators of the resilient modulus susceptibility to changes in water content.The results showed that the percentage of fractured coarse aggregates particles(FR)has a more significant impact on the resilient modulus(Er)of crushed granular materials used in pavement construction than the combined indicator of the fines content and sample volumetrics(nf).Crushed granular materials with a higher percentage of fractured coarse aggregates are relatively insensitive to changes in the degree of saturation,but become more sensitive as the fine fraction porosity decreases.An adjusted model was proposed based on the existing formulation,but considers a complex parameter to describe and adjust the sensitivity of base granular materials to variations in moisture content with respect to fabrication charac-teristics,fines content and volumetric properties.The model shows that the variation of Er values is below10%for fully crushed granular materials.However,it reaches approximately±12%for materials with 75%of crushed coarse aggregates andþ40%and-25%for materials with FR=50%.This model could help select good ag-gregates characteristics and adjust grain-size distribution for environments where significant moisture content variations can occur in the pavement system,such as in the Province of Quebec(Canada).As it is based on pa-rameters that can be easily determined or estimated,it also represents a valuable tool for detailed design and analysis that can consider material characteristics.
基金supported by the National Key Research and Development Program of China(2022YFB3205500,and 2022YFC3104700)the National Natural Science Foundation of China(62101329 and 61971284)+4 种基金the Shanghai Sailing Program(21YF1421400)the Natural Science Foundation of Shanghai(23ZR1430100)the Oceanic Interdisciplinary Program of Shanghai Jiao Tong University(SL2020ZD203,SL2021MS006 and SL2020MS031)Scientific Research Fund of Second Institute of Oceanography,Ministry of Natural Resources of P.R.China(SL2003)Startup Fund for Youngman Research at Shanghai Jiao Tong University.
文摘Human metabolite moisture detection is important in health monitoring and non-invasive diagnosis.However,ultra-sensitive quantitative extraction of respiration information in real-time remains a great challenge.Herein,chemiresistors based on imine-linked covalent organic framework(COF)films with dual-active sites are fabricated to address this issue,which demonstrates an amplified humidity-sensing signal performance.By regulation of monomers and functional groups,these COF films can be pre-engineered to achieve high response,wide detection range,fast response,and recovery time.Under the condition of relative humidity ranging from 13 to 98%,the COFTAPB-DHTA film-based humidity sensor exhibits outstanding humidity sensing perfor-mance with an expanded response value of 390 times.Furthermore,the response values of the COF film-based sensor are highly linear to the relative humidity in the range below 60%,reflecting a quantitative sensing mechanism at the molecular level.Based on the dual-site adsorption of the(-C=N-)and(C-N)stretching vibrations,the revers-ible tautomerism induced by hydrogen bonding with water molecules is demonstrated to be the main intrinsic mechanism for this effective humidity detection.In addition,the synthesized COF films can be further exploited to effectively detect human nasal and oral breathing as well as fabric permeability,which will inspire novel designs for effective humidity-detection devices.
基金supported by the National Key Research and Development Program of China (2018YFB1502502)the National Natural Science Foundation of China (22179127)。
文摘Humidity can affect the attenuation of MEA(membrane electrode assembly), however, the relationship between humidity and MEA decays is complex and ambiguous in realistic application. Herein, we design a simulating automotive protocol, performed on five single fuel cells under RH(relative humidity) 100%,RH 80%, RH 64%, and RH 40%, RH 10%, respectively, to study the relationship of MEA decays and humidity and suggest optimized humidity range to extend the durability. With the electrochemical impedance spectroscopy, cyclic voltammetry, X-ray fluorescence, X-ray diffraction, transmission electron microscope, X-ray photoelectron spectroscopy, the four degradation mechanisms about catalyst layer, including Pt dissolution, Pt coarsening, carbon corrosion and ionomer degradation, are observed. Pt coarsening and carbon corrosion are accelerated by higher water content at high humidity. Ionomer degradation and Pt dissolution are enhanced in low humidity. With the linear sweep voltammetry, ion chromatography,nuclear magnetic resonance, tensile test and scan electron microscope, chemical and mechanical degradation in proton exchange membrane are all observed in these five fuels. Chemical degradation, characterized by membrane thinning and more fluoride loss, occurred markedly in RH 10%. Mechanical degradation, characterized by the non-uniformity thickness and bad mechanical properties, is more pronounced in RH 100%, RH 80%, RH 64%. These two degradations are in a moderate level in RH 40%. The research suggests that the RH range from 64% to 40% is conductive to mitigate the degradation of MEAs operated in automotive applications.
基金This study was supported by the National Natural Science Foundation of China (52105593 and 62271439)STI 2030 —Major Projects(2022ZD0208601)the “Pioneer” and “Leading Goose” R&D Program of Zhejiang (2023C01051)。
文摘Flexible and wearable humidity sensors play a vital role in daily point-of-care diagnosis and noncontact human-machine interactions.However,achieving a facile and high-speed fabrication approach to realizing flexible humidity sensors remains a challenge.In this work,a wearable capacitive-type Ga_(2)O_(3)/liquid metal-based humidity sensor is demonstrated by a one-step laser direct writing technique.Owing to the photothermal effect of laser,the Ga_(2)O_(3)-wrapped liquid metal particles can be selectively sintered and converted from insulative to conductive traces with a resistivity of 0.19Ω·cm,while the untreated regions serve as active sensing layers in response to moisture changes.Under 95%relative humidity,the humidity sensor displays a highly stable performance along with rapid response and recover time.Utilizing these superior properties,the Ga_(2)O_(3)/liquid metal-based humidity sensor is able to monitor human respiration rate,as well as skin moisture of the palm under different physiological states for healthcare monitoring.
基金Jin Wu acknowledges financial support from the National Natural Science Foundation of China(No.61801525)the Guangdong Basic and Applied Basic Research Foundation(No.2020A1515010693)+1 种基金the Fundamental Research Funds for the Central Universities,Sun Yat-sen University(No.22lgqb17)the Independent Fund of the State Key Laboratory of Optoelectronic Materials and Technologies(Sun Yat-sen University)under grant No.OEMT-2022-ZRC-05.
文摘Breathing is an inherent human activity;however,the composition of the air we inhale and gas exhale remains unknown to us.To address this,wearable vapor sensors can help people monitor air composition in real time to avoid underlying risks,and for the early detection and treatment of diseases for home healthcare.Hydrogels with three-dimensional polymer networks and large amounts of water molecules are naturally flexible and stretchable.Functionalized hydrogels are intrinsically conductive,self-healing,self-adhesive,biocompatible,and room-temperature sensitive.Compared with traditional rigid vapor sensors,hydrogel-based gas and humidity sensors can directly fit human skin or clothing,and are more suitable for real-time monitoring of personal health and safety.In this review,current studies on hydrogel-based vapor sensors are investigated.The required properties and optimization methods of wearable hydrogel-based sensors are introduced.Subsequently,existing reports on the response mechanisms of hydrogel-based gas and humidity sensors are summarized.Related works on hydrogel-based vapor sensors for their application in personal health and safety monitoring are presented.Moreover,the potential of hydrogels in the field of vapor sensing is elucidated.Finally,the current research status,challenges,and future trends of hydrogel gas/humidity sensing are discussed.
基金supported by the National Key Research and Development Program of China(No.2019YFD1002004).
文摘The environment significantly impacts the interaction between plants and pathogens,thus remarkably affecting crop disease occurrence.However,the detailed combined mechanisms of temperature and humidity influencing this interaction remain unclear.In this study,the interaction between tomato and Botrytis cinerea in various temperature and humidity conditions was analyzed by histological observation and a dual RNA-seq approach.Results showed that low humidity was not favorable for mycelial growth,resulting in infection failure.Both high and low temperatures at high humidity successfully inhibited pathogenic infection and disease incidence in the tomato plants,thus enhancing their resistance to B.cinerea.The high temperature and high humidity(HH)treatment induced the upregulation of light reaction genes,increased the net photosynthetic rate,and expanded the chloroplast morphology of infected tomatoes.The HH treatment also inhibited the expression of cell cycle-related genes of B.cinerea,interfered with conidial germination andmycelial growth,and damagedmycelial cell structure.Lowtemperature and high humidity(LH)treatment induced the expression of cell wall modification genes and remodeled the cell wall morphology of tomatoes in response to B.cinerea.In addition,the downregulated fungal catabolic genes and the abnormal increase in electron density ofmycelial cells under LH treatment subsequently reduced the infection ability of B.cinerea.These results further explain the coupled effects of temperature and humidity on plant defenses and pathogen virulence,and provide a potential means to control gray mold.
基金The project is supported by the National Natural Science Foundation of China （60074031, 60474052）.
文摘Capacitive humidity sensors were made of nanometer barium titanate.The pellets were prepared under different pressures between 3920N to 7850N force.The capacitance changes in three orders of magnitude in the relative humidity range of 10%～98%,indicating high humidity sensitivity of the sensors.At a certain measuring frequency,the capacitance of the sensors increases as increasing of the preparation pressure,while the sensitivity of the sensors basically remains the same.The frequencies corresponding to the peaks of the dielectric loss of the sensors move to the higher frequency direction as increasing of the relative humidity.At a certain humidity,the frequencies corresponding to the peaks of the dielectric loss move to the higher frequency direction as increasing of the preparation pressure.
基金supported by the National Key R&D Program of China(2017YFA0605101)the National Natural Science Foundation of China(31770489,41273098 and 31621091)
文摘The vertical distribution of vegetation types along an elevational gradient in mountain areas largely depends on the elevational changes in air temperature and humidity. In this study, we presented the seasonal and diurnal variations in the elevational gradients of air temperature and humidity on the southern and northern slopes in the middle Tianshan Mountain Range using data collected throughout the year via HOBO data loggers. The measurements were conducted at 12 different elevations from 1548 to 3277 m from September 2004 to August 2005. The results showed that the annual mean air temperature decreased along the elevational gradients with temperature lapse rates of(0.71±0.20)°C/100 m and(0.59±0.05)°C/100 m on the northern and southern slopes, respectively. The annual mean absolute humidity significantly decreased with increasing elevation on the northern slope but showed no significant trend on the southern slope. The annual mean relative humidity did not show a significant trend on the northern slope but increased with increasing elevation on the southern slope. The mean air temperature lapse rate exhibited significant seasonal variation, which is steeper insummer and shallower in winter, and this value varied between 0.37°C/100 m and 0.75°C/100 m on the southern slope and between 0.30°C/100 m and 1.02°C/100 m on the northern slope. The mean absolute and relative humidity also exhibited significant seasonal variations on both slopes, with the maximum occurring in summer and the minimum occurring in winter or spring. The monthly diurnal range of air temperature on both slopes was higher in spring than in winter. The annual range of air temperature on the southern slope was higher than that on the northern slope. Our results suggest that significant spatiotemporal variations in humidity and temperature lapse rate are useful when analyzing the relationships between species range sizes and climate in mountain areas.
文摘The development and character of compound temperature-humidity sensor were discussed in this study.The design of sampling,control and output unit of temperature-humidity sensor as well as their manufacture method and character were studied in detail.The relationship between components of humidity resistance materials and negative temperature coefficient ( NTC) thermistor materials in sampling unit of compound sensor and character of electrical resistance and temperature was obtained.Couples of character curves of compound temperature-humidity sensor and data of materials of sampling unit were shown in this paper too.
文摘An impedance type humidity sensor based on the polyacrylic emulsion containing magnesium chloride (MgCl_2) without chemical modification was investigated.The impedances of the sensor were measured from various relative humidity in the frequency range between 0.1kHz and 100 kHz.The sensor has a good sensitivity from 60%RH to 90%RH.According to the experimental results,the response time is about 240 seconds in the adsorption process and 310 seconds in the desorption process.
基金This work was supported by National Natural Science Foundation of China, Under Grant No.（60676044）
文摘This paper reports on the fabrication and sensing characteristics of Polyimide-based humidity sensor,based on that,a new integrated circuit of humidity measurement has been designed.It is a novel capacitive-type systems on a chip structure using the MEMS process.The results show that the new sensor presents sensing characteristics over a humidity range from 10%～70% RH at 20℃,and the sensor is able to fabricated together with ICs technology.The result shows that integration of humidity sensor with integrated circuit of humidity measurement is considerably easier when they are built in sensing groove.The appeal of a new structure like this brings the possibility of applications that would require the flexibility of simple screen printing.
文摘Soluble Poly(propargyl benzoate) (PPBT) with (-conjugated structure was synthesized using a novel bis(triphenylphosphine)-bisacetylide palladium complex catalyst [Pd(PPh3)2(C(CCH2OOCPh)2] (PPB). An interdigital gold electrode was covered by screen printing films of doped PPBT (DPPBT) to prepare a resistance-type humidity sensor, which exhibits electrical response towards relative humidity (RH%) variations in the range 11%-96%. PPBT shows promise as a new humidity-sensitive material.
文摘Poly(p-diethynylbenzene) (PDEB) with improved solubility was synthesized using anovel catalyst bis(triphenylphosphine)bis(p-diethnylbenzene) nickel complex (Ni-C). A surfaceacoustic wave (SAW) delay line oscillator was covered by Langmuir-Blodgett (LB) films of re-sulting PDEB to prepare a humidity sensor, which was found to have high sensitivity and goodrepeatability. PDEB shows promise as a good humidity-sensitive material.
文摘The effect of external roof shading on the spatial distribution of air temperature and relative humidity in a greenhouse(Tin and RHin) was evaluated under the arid climatic conditions of Riyadh City, Saudi Arabia. Two identical, evaporatively-cooled, single-span greenhouses were used in the experiment. One greenhouse was externally shaded(Gs) using a movable black plastic net(30% transmissivity), and the other greenhouse was kept without shading(Gc). Strawberry plants were cultivated in both greenhouses. The results showed that the spatial distribution of the Tin and RHin was significantly affected by the outside solar radiation and evaporative cooling operation. The regression analysis showed that when the outside solar radiation intensity increased from 200 to 800 W m–2, the Tin increased by 4.5℃ in the Gc and 2℃in the Gs, while the RHin decreased by 15% in the Gc and 5% in the Gs, respectively. Compared with those in the Gc, more uniformity in the spatial distribution of the Tin and RHin was observed in the Gs. The difference between the maximum and minimum Tin of 6.4℃ and the RHin of 10% was lower in the Gs than those in the Gc during the early morning. Around 2℃ difference in the Tin was shown between the area closed to the exhausted fans and the area closed to the cooling pad with the external shading. In an evaporatively-cooled greenhouse in arid regions, the variation of the Tin and RHin in the vertical direction and along the sidewalls was much higher than that in the horizontal direction. The average variation of the Tin and RHin in the vertical direction was 5.2℃ and 10% in the Gc and 5.5℃ and 13% in the Gs, respectively. The external shading improved the spatial distribution of the Tin and RHin and improved the cooling efficiency of the evaporative cooling system by 12%, since the transmitted solar radiation and accumulated thermal energy in the greenhouse were significantly reduced.
基金the Chinese Academy of Sciences(Project Nos.XDA19030402 and XDA20020201)the UK–China Research&Innovation Partnership Fund through the Met Office Climate Science for Service Partnership(CSSP)China as part of the Newton Fund(SFBT&NF).
文摘Surface relative humidity(RH)is a key element for weather and climate monitoring and research.However,RH is not as commonly applied in studying climate change,partly because the observation series of RH are prone to inhomogeneous biases due to non-climate changes in the observation system.A homogenized dataset of daily RH series from 746 stations in Chinese mainland for the period 1960–2017,ChinaRHv1.0,has been developed.Most(685 or 91.82%of the total)station time series were inhomogeneous with one or more break points.The major breakpoints occurred in the early 2000s for many stations,especially in the humid and semi-humid zones,due to the implementation of automated observation across the country.The inhomogeneous biases in the early manual records before this change are positive relative to the recent automatic records,for most of the biased station series.There are more break points detected by using the MASH(Multiple Analysis of Series for Homogenization)method,with biases mainly around?0.5%and 0.5%.These inhomogeneous biases are adjusted with reference to the most recent observations for each station.Based on the adjusted observations,the regional mean RH series of China shows little long-term trend during 1960–2017[0.006%(10 yr)^?1],contrasting with a false decreasing trend[?0.414%(10 yr)?1]in the raw data.It is notable that ERA5 reanalysis data match closely with the interannual variations of the raw RH series in China,including the jump in the early 2000s,raising a caveat for its application in studying climate change in the region.
基金supported by the National Natural Science Foundation of China(30900141)the Chinese Academy of Sciences(KSCX2-EW-J-22,09C302,Y0B3011)the Chinese Academy of Sciences(KSCX2-YW-R-077)
文摘Generally, the function of vocalizations made by male anurans are to attract females or defend resources. Typically, males vocalize in choruses during one or more periods in a twenty-four-hour cycle, which varies, however, among species. Nevertheless, the causal factors influencing circadian variations of calling patterns in anuran species are not clear. In this study, male chorus vocalizations were monitored in the Emei music frog(Babina daunchina) for 17 consecutive days during the breeding season, while its habitat air temperature and relative humidity in the course of experiments were measured as well. The results revealed that the circadian calling patterns were characterized by two periods of peak vocalization, which were observed from 0500 h to 0700 h and from 1300 h to 2000 h, while the lowest activity period was found from 2100 h to 2200 h. Both calls/h and notes/h were positively correlated with air temperature and negatively with relative humidity. Overall, our data indicate that the Emei music frogs(B. daunchina) could regulate their vocal activities based on the changes of physical micro-environment(e. g., temperature or humidity) to maximize reproductive success.
基金The financial support from Yue Qi Young Scholar Project,China University of Mining and Technology-BeijingChina Scholarship CouncilBGRIMM Technology Group。
文摘Cemented paste backfill(CPB),a mixture of tailings,binder,and water,is widely and extensively used for the recovery of mineral resources,the prevention of ground subsidence,and the management of mine waste.When installed,the CPB is subjected to complex environmental conditions such as water content,temperature,and power,which have a significant impact on its efficiency.Thus,this study conducts a series of laboratory programs,including investigation of moisture,temperature,stress–strain relation,and microstructure to show the effect of curing humidity on the CPB behaviors.The results obtained indicate that ambient humidity can have a dramatic effect on CPB in terms of its macro performance of internal relative humidity,temperature and strength,as well as the micro expression.Typical examples of these effects on CPB include an increase in curing humidity,which favors binder hydration,and then an increase in hydration materials,temperature and peak stress in the CPB.The results obtained will lead to a better understanding of CPB’s responses to various environmental conditions.
基金provided by the National Basic Research Program of China (No.2010CB226804)
文摘As the depth of exploitation increases,studies on constitutive models of rock affected by temperature and humidity become very important.Based on the Nishihara model,a visco-elastic-plastic rock model was established by using the coefficients of thermal and humidity expansion,thermal viscosity attenuation,humid viscosity attenuation and acceleration rheology components.We used the definition of a controlled heat circle to explain the model.The results show that the behavior of rock,affected by temperature and humidity,is stable as a function of time when the stress is lower than the first yield stress σS1;the creep rate will increase due to the effect of temperature and humidity when the stress is greater than or equal to σS1;the creep rate will accelerate at an increasing rate when the stress is greater than or equal to the second yield stress σS2,which results in a failure of the roadway.The model derived in this study can completely describe visco-elastic-plastic characteristics and reflects the three stages of rock creep.
基金Under the auspices of National Natural Science Foundation of China(No.41871343)Major Project of National Natural Science Foundation of China(No.41590842)Strategic Priority Research Program A of the Chinese Academy of Sciences(No.XDA23100201)
文摘The cooling and humidifying effects of urban parks are an essential component of city ecosystems in terms of regulating microclimates or mitigating urban heat islands(UHIs).Air temperature and relative humidity are two main factors of thermal environmental comfort and have a critical impact on the urban environmental quality of human settlements.We measured the 2-m height air temperature and relative humidity at the Beijing Olympic Park and a nearby building roof for more than 1 year to elucidate seasonal variations in air temperature and relative humidity,as well as to investigate the outdoor thermal comfort.The results showed that the lawn of the park could,on average,reduce the air temperature by(0.80±0.19)℃,and increase the relative humidity by(5.24±2.91)% relative to the values measured at the building roof during daytime.During the nighttime,the lawn of the park reduced the air temperature by(2.64±0.64)℃ and increased the relative humidity by(10.77±5.20)%.The park was cooler and more humid than surrounding building area,especially in night period(more pronounced cooling with 1.84℃).Additionally,the lawn of the park could improve outdoor thermal comfort through its cooling and humidifying effects.The level of thermal comfort in the park was higher than that around the building roof for a total of 11 days annually in which it was above one or more thermal comfort levels(average reduced human comfort index of 0.92)except during the winter.
