Long-term ocean temperature trend and marine heatwaves

Marine heatwaves(MHWs)can cause irreversible damage to marine ecosystems and livelihoods.Appropriate MHW characterization remains difficult,because the choice of a sea surface temperature(SST)temporal baseline strongly influences MHW identification.Following a recent work suggesting that there should be a communicating baseline for long-term ocean temperature trends(LTT)and MHWs,we provided an effective and quantitative solution to calculate LTT and MHWs simultaneously by using the ensemble empirical mode decomposition(EEMD)method.The long-term nonlinear trend of SST obtained by EEMD shows superiority over the traditional linear trend in that the data extension does not alter prior results.The MHWs identified from the detrended SST data exhibited low sensitivity to the baseline choice,demonstrating the robustness of our method.We also derived the total heat exposure(THE)by combining LTT and MHWs.The THE was sensitive to the fixed-period baseline choice,with a response to increasing SST that depended on the onset time of a perpetual MHW state(identified MHW days equal to the year length).Subtropical areas,the Indian Ocean,and part of the Southern Ocean were most sensitive to the long-term global warming trend.

Magnetoresistance enhancement and temperature stability of magnetoresistance in La_(1-x)(Sr_(1-y)Na_y)_xMnO_3

A series of the samples La_(1-x)(Sr_(1-y)Na_y)_xMnO_3(y=0.0,0.2,0.4,0.6,0.8,1.0) were prepared by the solid-state reaction method.Magnetoresistance enhancement and temperature stability of magnetoresistance in the system La_(1-x)(Sr_(1-y)Na_y)_xMnO_3 with unchanged Mn^(3+)/Mn^(4+) ratio through the doping of both monovalent and divalent elements at A site were studied through the measurements of X-ray diffraction(XRD) patterns,resistivity-temperature(ρ-T) curves and magnetoresistance-temperature(MR-T) curves.The results indicate that with the increase of Na doping amount,the peak value of MR increases,and it increases from 12.4% for y=0.2 to 50.6% for y=1.0 in the magnetic field B=0.8 T;ρ-T curves exhibit the double-peak phenomenon,which comes from the competition between the resistivity of surface phase and that of body phase;for the sample of y=0.8,MR increases slowly from 8.3% to 9.4% in the temperature range from 259 to 179 K,and MR is so stable in such a wide temperature range,which provides reference for the research on the temperature stability of MR.

Innovation for forming aluminum alloy thin shells at ultra-low temperature by the dual enhancement effect

Integral thin shells made of high strength aluminum alloys are urgently needed in new generation transportation equipment. There are challenges to overcoming the co-existing problems of wrinkling and splitting by the cold forming and hot forming processes. An innovative technology of ultra-low temperature forming has been invented for aluminum alloy thin shells by the new phenomenon of ‘dual enhancement effect’. That means plasticity and hardening are enhanced simultaneously at ultra-low temperatures. In this perspective, the dual enhancement effect is described, and the development, current state and prospects of this new forming method are introduced. This innovative method can provide a new approach for integral aluminum alloy components with large size, ultra-thin thickness, and high strength. An integral tank dome of rocket with 2 m in diameter was formed by using a blank sheet with the same thickness as the final component, breaking through the limit value of thickness-diameter ratio.

Temperature stability of magnetoresistance (MR) and MR enhancement in La_(1-x)(Sr_(1-y)Ag_y)_x MnO_3 system

Polycrystalline samples of Lal-x（Srl-yAgy）x MnO3 （y = 0.0, 0.2, 0.4, 0.6, 1.0） were prepared by the solid-state reaction method. The temperature stability of magnetoresistance and magnetoresistance enhancement in Lal_x（Srl_yAgy）~MnO3 system with both univalent and bivalent elements doped at A site and with unchanged value of Mn~＋/Mn4＋ ratio were explored through the measurements of X-ray diffraction patterns, magnetiza- tion-temperature （M-T） curves, resistivity-temperature （p-T） curves and magnetoresistance-temperature （MR-T） curves. The results are as follows： there are two peaks in the p-T curves of the samples with Ag doping, one is caused by resistance change during the paramagnetism- ferromagnetism transition, and the other is from boundary- dependent scattering of conduction electrons on the boundaries of grains. The peak value of MR increases with increasing Ag doping content, and it increases from 8.2 % for y ---- 0.2 to 29.6 % for y ---- 1.0 under the magnetic field of B = 0.8 T; MR remains a constant of 12 % in the temperature range of 218-168 K for the sample with y = 1.0, and the temperature stability of MR is in favor of the practical application of MR.

Heat-induced temperature enhancement in the polar summer ionosphere

Observation data recorded by the European Incoherent Scatter Scientific Association in TromsФ, Norway in August 2009 were analyzed to determine the heating effects in polar summer ionospheric modification experiments. There are two types of increases in electron temperature： large relative increases in a narrow range near 150 km and greater absolute increases in a wider range at 150-400 km. The percentage increase in temperature linearly increases with heating power, but the rate of increase decreases with increasing pump frequency. A clear two-dimensional distribution was found for the measurement made on August 15, and the beating effects are greater closer to the direction of the geomagnetic field. The heating effects obviously depend on the angle between the heating beam and geomagnetic field; as the angle increases, the heating effect decreases.

Study of Temperature Enhancement of the Photorefractive Effect in Ce：Fe：LiNbO_3 Crystal

in the range of 20 to 120 ℃, the two-beam coupling exponential gain coefficient and the four-wave mixing phase conjugation reflectivity have been investigated. It is shown that the values such as the gain, the phase conjugation reflectivity and the response speed increase as the temperature increases. At about 55, 71 and 110℃, extraordinary enhancement of the gain and the phase conjugation reflectivity were observed.The mechanism is analyzed by the phase change in the crystal at these temperatures.

Analysis on Long-Term Change of Sea Surface Temperature in the China Seas

Long-term change of sea surface temperature （SST） in the China Seas from 1900 to 2006 is examined based on two different observation datasets （HadlSSTI and HadSST3）. Similar to the Atlantic, SST in the China Seas has been well observed during the past 107 years. A comparison between the reconstructed （HadISSTI） and un-interpolated （HadSST3） datasets shows that the SST wanning trends from both datasets are consistent with each other in most of the China Seas. The warming trends are stronger in winter than in summer, with a maximum rate of SST increase exceeding 2.7℃ （100year）-I in the East China Sea and the Taiwan Strait during winter based on HadISSTI. However, the SST from both datasets experienced a sudden decrease after 1999 in the China Seas. The estimated trend from HadlSSTI is stronger than that fi＇om HadSST3 in the East China Sea and the east of Taiwan Island, where the difference in the linear SST warming trends are as large as about 1℃ （100year）-I when using respectively HadISST1 and HadSST3 datasets. When compared to the linear winter warnling trend of the land surface air temperature （1.6℃ （100 year）-1）, HadSST3 shows a more reasonable trend of less than 2.1℃（ 100 year）-1 than HadISST 1 ＇s trend of larger than 2.7℃ （ 100 year）-1 at the mouth of the Yangtze River. The restllts also indicate large uncertainties in the estimate of SST warming patterns.

The long-term variability of sea surface temperature in the seas east of China in the past 40 a

The global surface temperature change since the mid-19th century has caused general concern and intensive study. However, long-term changes in the marginal seas, including the seas east of China, are not well understood because long-term observations are sparse and, even when they exist, they are over limited areas. Preliminary results on the long-term variability of sea surface temperature （SST） in summer and winter in the seas east of China during the period of 1957-2001 are reported using the Ocean Science Database of Institute of Oceanology, Chinese Academy of Sciences, the coastal hydrological station in situ and satellite data. The results show well-defined warming trends in the study area. However warming and cooling trends vary from decade to decade, with steady and rapid warming trends after the 1980s and complicated spatial patterns. The distribution of SST variation is intricate and more blurred in the areas far away from the Kuroshio system. Both historical and satellite data sets show significant warming trends after 1985. The warming trends are larger and spread to wider areas in winter than in summer, which means decrease in the seasonal cycle of SST probably linked with recently observed increase of the tropical zooplankton species in the region. Spatial structures of the SST trends are roughly consistent with the circulation pattern especially in winter when the meridional SST gradients are larger, suggesting that a horizontal advection may play an important role in the long-term SST variability in winter.

Long-Term Trends in Extreme Temperatures in Hong Kong and Southern China

The observed long-term trends in extreme temperatures in Hong Kong were studied based on the meteorological data recorded at the Hong Kong Observatory Headquarters from 1885-2008. Results show that, over the past 124 years, the extreme daily minimum and maximum temperatures, as well as the length of the warm spell in Hong Kong, exhibit statistically significant long-term rising trends, while the length of the cold spell shows a statistically significant decreasing trend. The time-dependent return period analysis also indicated that the return period for daily minimum temperature at 4°C or lower lengthened considerably from 6 years in 1900 to over 150 years in 2000, while the return periods for daily maximum temperature reaching 35°C or above shortened drastically from 32 years in 1900 to 4.5 years in 2000. Past trends in extreme temperatures from selected weather stations in southern China from 1951-2004 were also assessed. Over 70% of the stations studied yielded a statistically significant rising trend in extreme daily minimum temperature, while the trend for extreme maximum temperatures was found to vary, with no significant trend established for the majority of stations.

Temperature effect on performance of nanoparticle/surfactant flooding in enhanced heavy oil recovery

Recently,nanoparticles have been used along with surfactants for enhancing oil recovery.Although the recent studies show that oil recovery is enhanced using nanoparticle/surfactant solutions,some effective parameters and mechanisms involved in the oil recovery have not yet been investigated.Therefore,the temperature effect on the stability of nanoparticle/surfactant solutions and ultimate oil recovery has been studied in this work,and the optimal concentrations of both SiO2 nanoparticle and surfactant(sodium dodecyl sulfate)have been determined by the Central Composite Design method.In addition,the simultaneous effects of parameters and their interactions have been investigated.Study of the stability of the injected solutions indicates that the nanoparticle concentration is the most important factor affecting the solution stability.The surfactant makes the solution more stable if used in appropriate concentrations below the CMC.According to the micromodel flooding results,the most effective factor for enhancing oil recovery is temperature compared to the nanoparticle and surfactant concentrations.Therefore,in floodings with higher porous medium temperature,the oil viscosity reduction is considerable,and more oil is recovered.In addition,the surfactant concentration plays a more effective role in reservoirs with higher temperatures.In other words,at a surfactant concentration of 250 ppm,the ultimate oil recovery is improved about 20%with a temperature increase of 20°C.However,when the surfactant concentration is equal to 750 ppm,the temperature increase enhances the ultimate oil recovery by only about 7%.Finally,the nanoparticle and surfactant optimum concentrations determined by Design-Expert software were equal to 46 and 159 ppm,respectively.It is worthy to note that obtained results are validated by the confirmation test.

Enhanced Disinfection Effect of a Compound Disinfectant against Bovine Herpes Virus Type 1 at Low Temperature

A compound disinfectant, which consisted of didecyldimethylammonium chloride (DDAC), ortho-dichlorobenzene (1,2-dichlorobenzene, ODB), and chlorocresol (4-chloro-3-methylphenol, CC), and its component chemicals were individually tested for effectiveness against bovine herpes virus type 1 (BHV-1). DDAC, DDAC+ODB, DDAC+CC, and DDAC+ODB+CC showed effectiveness against BHV-1 at room temperature. However, ODB, CC, and ODB+CC showed no virucidal effects. The effects of all disinfectants tested were decreased at low temperature. DDAC showed disinfectant effects at a dilution of 1/800 and DDAC+ODB, DDAC+CC, and DDAC+ODB+CC at dilutions of 1/800 and 1/1600 at low temperature in the presence of 2% fetal bovine serum (FBS) but ODB, CC, and ODB+CC showed no virucidal effects. At low temperature and in the presence of 10% FBS, DDAC, DDAC+ODB, and DDAC+CC showed disinfectant effects at dilutions of 1/800, whereas ODB, CC, and ODB+CC showed no virucidal effects. DDAC+ ODB+CC was more effective (at 1/800 and 1/1600) than the other disinfectants under these conditions. In conclusion, a combination of three disinfectant components (DDAC+ODB+CC), enhanced the disinfectant effects at low temperature and in organic matter contamination.

Experimental investigation for temperature and emissivity by flame emission spectrum in a cavity of rocket based combined cycle combustor chamber

Flame temperature and spectral emissivity were the important parameters characterizing the sufficient degree of fuel combustion and the particle radiative characteristics in the Rocket Based Combined Cycle(RBCC)combustor.To investigate the combustion characteristics of the complex supersonic flame in the RBCC combustor,a new radiation thermometry combined with Levenberg-Marquardt(LM)algorithm and the least squares method was proposed to measure the temperature,emissivity and spectral radiative properties based on the flame emission spectrum.In-situ measurements of the flame temperature,emissivity and spectral radiative properties were carried out in the RBCC direct-connected test bench with laser-induced plasma combustion enhancement(LIPCE)and without LIPCE.The flame average temperatures at fuel global equivalence ratio(a)of 1.0b and 0.6 with LIPCE were 4.51%and 2.08%higher than those without LIPCE.The flame combustion oscillation of kerosene tended to be stable in the recirculation zone of cavity with the thermal and chemical effects of laser induced plasma.The differences of flame temperature at a=1.0b and 0.6 were 503 K and 523 K with LIPCE,which were 20.07%and42.64%lower than those without LIPCE.The flame emissivity with methane assisted ignition was 80.46%lower than that without methane assisted ignition,due to the carbon-hydrogen ratio of kerosene was higher than that of methane.The spectral emissivities at 600 nm with LIPCE were 1.25%,22.2%,and 4.22%lower than those without LIPCE at a=1.0a(with methane assisted ignition),1.0b(without methane assisted ignition)and 0.6.The effect of concentration in the emissivity was removed by normalization to analyze the flame radiative properties in the RBCC combustor chamber.The maximum differences of flame normalized emissivity were 50.91%without LIPCE and 27.53%with LIPCE.The flame radiative properties were stabilized under the thermal and chemical effects of laser induced plasma at a=0.6.

Further-Adjusted Long-Term Temperature Series in China Based on MASH

A set of homogenized monthly mean surface air temperature （SAT） series at 32 stations in China back to the 19th century had previously been developed based on the RHtest method by Cao et al., but some inhomogeneities remained in the dataset. The present study produces a further-adjusted and updated dataset based on the Multiple Analysis of Series for Homogenization （MASH） method. The MASH procedure detects 33 monthly temperature records as erroneous outliers and 152 meaningful break points in the monthly SAT series since 1924 at 28 stations. The inhomogeneous parts are then adjusted relative to the latest homogeneous part of the series. The new data show significant warming trends during 1924-2016 at all the stations, ranging from 0.48 to 3.57℃ （100 yr）^-1, with a regional mean trend of 1.65℃ （100 yr）^-1 ; whereas, the previous results ranged from a slight cooling at two stations to considerable warming, up to 4.5℃ （100 yr）^-1. It is suggested that the further-adjusted data are a better representation of the large-scale pattern of climate change in the region for the past century. The new data axe available online at http：//www.dx.doi.org/10.11922/sciencedb.516.

Estimation of enhanced low dose rate sensitivity mechanisms using temperature switching irradiation on gate-controlled lateral PNP transistor

The mechanisms occurring when the switched temperature technique is applied,as an accelerated enhanced low dose rate sensitivity(ELDRS)test technique,are investigated in terms of a specially designed gate-controlled lateral PNP transistor(GLPNP)that used to extract the interface traps(Nit)and oxide trapped charges(Not).Electrical characteristics in GLPNP transistors induced by ^(60)Co gamma irradiation are measured in situ as a function of total dose,showing that generation of Nit in the oxide is the primary cause of base current variations for the GLPNP.Based on the analysis of the variations of Nit and Not,with switching the temperature,the properties of accelerated protons release and suppressed protons loss play critical roles in determining the increased Nit formation leading to the base current degradation with dose accumulation.Simultaneously the hydrogen cracking mechanisms responsible for additional protons release are related to the neutralization of Not extending enhanced Nit buildup.In this study the switched temperature irradiation has been employed to conservatively estimate the ELDRS of GLPNP,which provides us with a new insight into the test technique for ELDRS.

Analysis of Temperature Trends and Variations in the Arabian Peninsula’s Upper Atmosphere

In this study, the trends of upper-air temperatures are analysed by utilising radiosonde observations for the barometric levels at 700, 500, 300, 200, 150, 100 and 50 hPa from five meteorological stations within the Arabian Peninsula from January 1986 to August 2015. The mean monthly variations of the temperatures at these levels are characterised and established. The magnitudes of the annual trends of the mean temperatures for each site for the selected barometric levels are studied and statistically tested using Mann-Kendall rank statistics at different significance levels. The temperature trends at different pressure levels show that the upper troposphere and lower stratosphere are warming, while the middle troposphere is cooling which is consistent with the findings of other studies. The variations in upper air temperature observed in this study can be attributed to a range of factors, including increasing greenhouse gas concentrations, changes in atmospheric circulation patterns, variations in solar activity, aerosols and volcanic eruptions, and land use and land cover change.

Metal nanoparticle-enhanced room temperature phosphorescence of diiodofluorescein on the filter paper substrate

Metal-enhanced room temperature phosphorescence of diiodofluorescein was first observed on filter paper surface.The phosphorescence intensity is 2.5-fold brighter from diiodofluorescein on silver nanoparticles-deposited filter paper as compared with an identical control sample without silver nanoparticles.Furthermore,enhanced absorption was also observed for the same system.Our findings suggest that both singlet and triplet states can couple to surface plasmons and enhance phosphorescence quantum yields at ...

UV-Enhanced Room Temperature Ozone Sensor Based on Hierarchical SnO_2-In_2O_3

SnO2-ln2O3 hierarchical microspheres were prepared by the hydrothermal and solvothermal method. The morphology, phase crystallinity of the obtained SnO2-In203 were measured by X-ray diffraetion（XRD）, scan electron microscopy（SEM）, respectively. A room temperature ozone sensor based on SnO2-In2O3 hierarchical microspheres was fabricated and investigated. The gas sensing properties of the sensor using SnO2-In2O3 strongly depended on the proportion of SnO2 and In2O3. The sensitivity and response/recovery speed were greatly enhanced by UV illumination. A gas sensing mechanism related to oxygen defect was suggested.

Temperature/salt tolerance and oil recovery of xanthan gum solution enhanced by surface-modified nanosilicas

Amide-and alkyl-modified nanosilicas(AANPs)were synthesized and introduced into Xanthan gum(XG)solution,aiming to improve the temperature/salt tolerance and oil recovery.The rheological behaviors of XG/AANP hybrid dispersions were systematically studied at different concentrations,temperatures and inorganic salts.At high temperature(75C)and high salinity(10,000 mg,L1 NaCl),AANPs increase the apparent viscosity and dynamic modulus of the XG solution,and XG/AANP hybrid dispersion exhibits elastic-dominant properties.The most effective concentrations of XG and AANP interacting with each other are 1750 mg·L^(-1) and 0.74 wt%,respectively.The temperature tolerance of XG solution is not satisfactory,and high temperature further weakens the salt tolerance of XG.However,the AANPs significantly enhance the viscoelasticity the XG solution through hydrogen bonds and hydrophobic effect.Under reservoir conditions,XG/AANP hybrid recovers approximately 18.5%more OOIP(original oil in place)than AANP and 11.3%more OOIP than XG.The enhanced oil recovery mechanism of the XG/AANP hybrid is mainly increasing the sweep coefficient,the contribution from the reduction of oil-water interfacial tension is less.

FEM Model of the Temperature Distribution in the Brain during Enhanced Infrared Neural Stimulation Using Nanoparticles

Objectives: Enhanced infrared neural stimulation (EINS) using nanoparticles is a new research hotspot. In this paper, the numerical modeling of the interaction between a light source and brain tissue during EINS is studied. Materials and Methods: This model is built with the finite element method (FEM) to mimic the propagation and absorption of light in brain tissue with EINS. Only the thermal change is considered in this model since the photothermal effect is the main mechanism of EINS. The temperature response of brain irradiation is governed by the extensively used Pennes’ bio-heat equation in a multilayer model. Results: The temperature distribution in the brain under laser irradiation is determined. And the relationships between the brain tissue temperature and the three factors (the laser pulse time, the laser energy and the enhanced absorption coefficient of the tissue caused by the nanoparticles) are analyzed. Conclusions: The results indicate that the brain tissue is easier to warm up with the enhancement of nanoparticles and parameters of the laser can alter the temperature increase of the brain tissue. These findings offer a theoretical basis for future animal experiments.

Long-Term Trends and Its Best Functional Form Estimation of Yearly Maximum and Minimum Temperatures at Cotonou City by Improved Complete Ensemble Empirical Mode Decomposition with Adaptive Noise Method

The understanding of the long-term trend in climatic variables is necessary for the climate change impacts studies and for modeling several processes in environmental engineering. However, for climatic variables, long-term trend is usually unknown whether there is a trend component and, if so, the functional form of this trend is also unknown. In this context, a conventional strategy consists to assume randomly the shape of the local trends in the time series. For example, the polynomial forms with random order are arbitrarily chosen as the shape of the trend without any previous justification. This study aims to 1) estimate the real long-term nonlinear trend and the changing rate of the yearly high temperature among the daily minimum (YHTaDMinT) and maximum temperatures (YHTaDMaxT) observed at Cotonou city, 2) find out for these real trend and trend increment, the best polynomial trend model among four trend models (linear, quadratic, third-order and fourth-order polynomial function). For both time series, the results show that YHTaDMinT and YHTaDMaxT time series are characterized by nonlinear and monotonically increasing trend. The trend increments present different phases in their nonmonotone variations. Among the four trend estimations models, the trend obtained by third-order and fourth-order polynomial functions exhibits a close pattern with the real long-term nonlinear trend given by the Improved Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (ICEEMDAN). But, the fourth-order polynomial function is optimal, therefore, it can be used as the functional form of trend. In the trend increment case, for the YHTaDMaxT time series, the fourth-order fit is systematically the best among the four proposed trend models. Whereas for the YHTaDMinT time series, the third-order and fourth-order polynomial functions present the same performance. They can both be used as the functional form of trend increments. Overall, the fourth-order polynomial function presents a good performance in terms of trend and trend increments estimation.