Vertical structure of tidal currents in the Xuliujing Section of Changjiang River Estuary

Three long-term fixed acoustic Doppler current profilers were first used for investigating the vertical structure of tidal currents in Xuliujing Section of Changjiang River Estuary.Moreover,three different periods(spring,summer and fall)were also considered for investigating seasonal variations.The semi-diurnal tides were the most energetic,with along-channel speed of up to 80 cm/s for M_(2)constituent,which dominates at all stations with percent energy up to 65%–75%during seasons.The shape of tidal ellipses of the most energetic semi-diurnal constituent M_(2)showed obvious polarization of the flow paralleling to the riverbank,with the minor semi-axis being generally less than 20%of the major one.The maximum velocity of mean current is appeared in top layers at all the three stations,and the velocity decreased with the depth.The seasonal variations of direction are also observed,which is probably caused by complex local topography since the erosion and deposition in riverbed.Observed vertical variation of four parameters of M_(2)ellipses,agreed well with the optimally fit frictional solutions in top and middle layers.However,there was an obvious difference between frictional model and observed data in the lower water column.Discrepancies are probably on account of stratification,which strengthens in summer and fall due to the freshening influence of the Changjiang River Estuary outflow.

Micro-Pulse Lidar Measurements of Aerosol Vertical Structure over the Loess Plateau

Knowledge of the vertical distribution of aerosols in the free troposphere is important for estimating their impact on climate. In this study, direct observations of the vertical distribution of aerosols in the free troposphere are made using surface Micro-Pulse Lidar (MPL) measurements. The MPL measurements were made at the Loess Plateau (35.95°N, 104.1°E), which is near the major dust source regions of the Taklimakan and Gobi deserts. The vertical distribution of the MPL backscattering suggested that nondust aerosols floated from ground level to an altitude of approximately 9 km around the source regions. Early morning hours are characterized by a shallow aerosol layer of a few hundred meters thick. As the day progresses, strong convective eddies transport the aero- sols vertically to more than 1500 m.

Evaluation of Cloud Vertical Structure Simulated by Recent BCC_AGCM Versions through Comparison With CALIPSO-GOCCP Data

ABSTRACT The abilities of BCC-AGCM2.1 and BCC_AGCM2.2 to simulate the annual-mean cloud vertical structure （CVS） were evaluated through comparison with GCM-Oriented CALIPSO Cloud Product （CALIPSO-GOCCP） data. BCC-AGCM2.2 has a dynamical core and physical processes that are consistent with BCC-AGCM2.1, but has a higher horizontal resolution. Results showed that both BCC-AGCM versions underestimated the global-mean total cloud cover （TCC）, middle cloud cover （MCC） and low cloud cover （LCC）, and that BCC_AGCM2.2 underestimated the global-mean high cloud cover （HCC）. The global-mean cloud cover shows a systematic decrease from BCCA-GCM2.1 to BCC_AGCM2.2, especially for HCC. Geographically, HCC is significantly overestimated in the tropics, particularly by BCC_AGCM2,1, while LCC is generally overestimated over extra-tropical lands, but significantly underestimated over most of the oceans, especially for subtropical marine stratocumulus clouds. The leading EOF modes of CVS were extracted. The BCC_AGCMs perform well in reproducing EOF1, but with a larger variance explained. The two models also capture the basic features of EOF3, except an obvious deficiency in eigen- vector peaks. EOF2 has the largest simulation biases in both position and strength of eigenvector peaks. Furthermore, we investigated the effects of CVS on relative shortwave and longwave cloud radiative forcing （RSCRF and RLCRF）. Both BCC_AGCM versions successfully reproduce the sign of regression coefficients, except for RLCRF in PC1. However, the RSCRF relative contributions from PC1 and PC2 are overestimated, while the relative contribution from PC3 is underes timated in both BCC_AGCM versions. The RLCRF relative contribution is underestimated for PC2 and overestimated for PC3.

Vertical Structure of Interannual Variability in Cross-Equatorial Flows over the Maritime Continent and Indian Ocean in Boreal Summer

This study investigates the vertical structure of variability in the cross-equatorial flows(CEFs)over the Maritime Continent and Indian Ocean in boreal summer,based on three reanalysis datasets:ERA-Interim,JRA-55 and NCEP-2.The results show a high consistency in the interannual variability among the reanalysis datasets,especially between ERAInterim and JRA-55,while great uncertainty exists in the decadal or long-term changes of CEFs.Further analyses on the interannual variability in CEFs indicate that there is a significant negative relationship between the upper-and lower-level CEFs over the Maritime Continent—that is,the northerlies at the upper level and southerlies at the lower level are both enhanced or weakened.This seesaw pattern is also significantly related to the CEFs over the Indian Ocean at the upper level and lower level(i.e.,the Somali jet).This close relationship between the upper-and lower-level CEFs and between the Maritime Continent and Indian Ocean is manifested as the leading mode of equatorial meridional winds in the vertical-zonal section over the Maritime Continent and Indian Ocean.Finally,it is found that ENSO is closely related to the vertical leading mode,and to all the CEFs at the upper and lower levels over the Maritime Continent and Indian Ocean.

TWO-DIMENSIONAL ALGEBRAIC SOLITARY WAVE AND ITS VERTICAL STRUCTURE IN STRATIFIED FLUID

The algebraic solitary wave and its associated eigenvalue problem in a deep stratified fluid with a free surface and a shallow upper layer were studied. And its vertical structure was examined. An exact solution for the derived 2D Benjamin-Ono equation was obtained, and physical explanation was given with the corresponding dispersion relation. As a special case, the vertical structure of the weakly nonlinear internal wave for the Holmboe density distribution was numerically investigated, and the propagating mechanism of the internal wave was studied by using the ray theory.

APPLICATIONS OF THE CLOUDSAT TROPICAL CYCLONE PRODUCT IN ANALYZING THE VERTICAL STRUCTURE OF TROPICAL CYCLONES OVER THE WESTERN PACIFIC

Cloud profiling radar(CPR) onboard Cloud Sat allows for deep penetration into dense clouds/precipitation. In this study, tropical cyclones(TCs) are classified into three stages as developing, mature, and decaying. The circular TC area with the radius of 500 km is divided into five regions. The vertical structure characteristics of 94 Western Pacific TCs at different stages in different regions from June 2006 to February 2014 are statistically quantified using the Cloud Sat tropical cyclone overpass product(the CSTC Product). Contoured frequency by altitude diagrams(CFADs) of radar reflectivity show an arc-like feature and exhibit opposite distributions with a boundary at 5 km. Bright bands are found at this altitude, indicating melting layers. Deep convective(DC) clouds have the largest occurrence probability in the inner region, while Ci clouds occur more frequently in the outer region at 10-15 km. As clouds have the second largest vertical scale after DC clouds. Distributions of Ac, Cu, and Ns clouds at different stages have few distinctions.As the altitude increases, the ice effective radius and the distribution width parameter decrease while the particle number concentration increases. Moist static energy(MSE), cloud thickness(CT), liquid water path(LWP), ice water path(IWP), water vapor(WV), and rain rate(RR) all diminish along the radial direction and are significantly larger at the mature stage. The average value of MSE at the developing stage is larger than that at the decaying stage.

Vertical structure and dominating factors of sand body during Late Triassic Chang 9 time of Yanchang Formation in Ordos Basin, NW China

Based on a synthetic geological study of drilling, well logging and core observations, two main genetic types of Chang 9sand body in Odors Basin were recognized, which included two effects, that is, delta environment and tractive current effects that lead to the development of mouth bar, distal bar, sheet sand and other sand bodies of subaerial and subaqueous distributary channel,natural levee, flood fan and delta front, and shore-shallow lake environment and lake flow transformation effects that result in the development of sandy beach bar, sheet sand and other sand bodies. Chang 9 sand body mainly developed five basic vertical structures, namely box shape, campaniform, infundibuliform, finger and dentoid. The vertical stacking patterns of multilayer sand body was complex, and the common shapes included box shape + box shape, campaniform + campaniform, campaniform + box shape, infundibuliform + infundibuliform, campaniform + infundibuliform, box shape + campaniform, box shape + infundibuliform,and finger + finger. Based on the analysis on major dominating factors of vertical structure of sand body, sedimentary environment,sedimentary facies and rise, fall and cycle of base level are identified as the major geological factors that control the vertical structure of single sand body as well as vertical stacking patterns and distribution of multistory sand bodies.

The effect of internal tides on the vertical structure of tidal current in the North Huanghai Sea

The tidal current is generally predominant in China's offshore areas. The vertical structure of the observedtidal current is quite complicated with the presence of seasonal thermocline. The observed tidal current may be divided into two parts, an averaged barotropic tide current and a variation tide current. A method for studying the vertical structure of tidal current is developed from the constitution and distribution of energy, and the vertical structure of the observed tide current in the North Huanghai Sea is studied on the basis of the method. The result shows that the reason why the energy of the tidal current is concentrated on the neighbourhood of the thermocline mainly lies in the internal tides i under certain conditions, the fact that the direction of the internal tide current above the thermocline is opposite to the one below the thermocline will be able to cause the rotary directions of the observed tidal current above and below the thermocline to be in opposite. The interaction between the averaged barotropic and the variation tide current plays an important role in forming the vertical structure of the tidal current, and it is mainly the interaction that results in the inho-mogeneous distribution of the tide current energy in the entire water column ; the ratio between the total energies of the internal tide current above the thermocline and the variation tide current in the entire water column is greater than the ratio between the total energies of that below the thermocline and the variation's. In a strong internal tide area such as the neighbourhood of Station L4, at diurnal tide frequency, the above-mentioned corresponding ratios are about 38. 82% and 29. 88%, respectively, and the energy of the internal tide current is about 68. 70%of the energy of the variation tide current; at semidiurnal tide frequency, the above-mentioned corresponding ratios are about 26. 61 % and 19. 73% , respectively, and the total internal tide current energy is about 46. 36% of the total variation tide current energy.

Revealing the vertical structure of in-situ fabricated perovskite nanocrystals films toward efficient pure red light-emitting diodes

The development of efficient perovskite light-emitting diodes(PeLEDs)relies strongly on the fabrication of perovskite films with rationally designed structures(grain size,composition,surface,etc.).Therefore,an understanding of structure-performance relationships is of vital importance for developing high-performance perovskite devices,particularly for devices with in-situ fabricated perovskite nanocrystal films.In this study,we reveal the vertical structure of an in-situ fabricated quasi-two-dimensional perovskite film.By combining time-of-flight secondary ion mass spectrometry,energy dispersive spectroscopy,grazing incidence wide-angle X-ray scattering(GIWAXS),and low-temperature photoluminescence spectra,we illustrate that the resulting in-situ fabricated DPPA_(2)Cs_(n-1)Pb_(n)(Br_(0.3)I_(0.7))_(3n+1)(DPPA^(+):3,3-diphenylpropylammonium)film has a gradient structure with a very thin layer of ligands on the surface,predominantly small-n domains at the top,and predominantly large-n domains at the bottom owing to the solubility difference of the precursors.In addition,GIWAXS measurements show that the domain of n=2 on the top layer has an ordered in-plane alignment.Based on the understanding of the film structure,we developed an in-situ fabrication process with ligand exchange to achieve efficient pure red PeLEDs at 638 nm with an average external quantum efficiency(EQE)of 7.4%.The optimized device had a maximum luminance of 623 cd/m^(2) with a peak EQE of 9.7%.

Tree species identity and interaction determine vertical forest structure in young planted forests measured by terrestrial laser scanning

Vertical forest structure is closely linked to multiple ecosystem characteristics,such as biodiversity,habitat,and productivity.Mixing tree species in planted forests has the potential to create diverse vertical forest structures due to the different physiological and morphological traits of the composing tree species.However,the relative importance of species richness,species identity and species interactions for the variation in vertical forest structure remains unclear,mainly because traditional forest inventories do not observe vertical stand structure in detail.Terrestrial laser scanning(TLS),however,allows to study vertical forest structure in an unprecedented way.Therefore,we used TLS single scan data from 126 plots across three experimental planted forests of a largescale tree diversity experiment in Belgium to study the drivers of vertical forest structure.These plots were 9–11years old young pure and mixed forests,characterized by four levels of tree species richness ranging from monocultures to four-species mixtures,across twenty composition levels.We generated vertical plant profiles from the TLS data and derived six stand structural variables.Linear mixed models were used to test the effect of species richness on structural variables.Employing a hierarchical diversity interaction modelling framework,we further assessed species identity effect and various species interaction effects on the six stand structural variables.Our results showed that species richness did not significantly influence most of the stand structure variables,except for canopy height and foliage height diversity.Species identity on the other hand exhibited a significant impact on vertical forest structure across all sites.Species interaction effects were observed to be site-dependent due to varying site conditions and species pools,and rapidly growing tree species tend to dominate these interactions.Overall,our results highlighted the importance of considering both species identity and interaction effects in choosing suitable species combinations for forest management practices aimed at enhancing vertical forest structure.

Different Turbulent Regimes and Vertical Turbulence Structures of the Urban Nocturnal Stable Boundary Layer

Turbulence in the nocturnal boundary layer(NBL)is still not well characterized,especially over complex underlying surfaces.Herein,gradient tower data and eddy covariance data collected by the Beijing 325-m tower were used to better understand the differentiating characteristics of turbulence regimes and vertical turbulence structure of urban the NBL.As for heights above the urban canopy layer(UCL),the relationship between turbulence velocity scale(VTKE)and wind speed(V)was consistent with the“HOckey-Stick”(HOST)theory proposed for a relatively flat area.Four regimes have been identified according to urban nocturnal stable boundary layer.Regime 1 occurs where local shear plays a leading role for weak turbulence under the constraint that the wind speed V<VT(threshold wind speed).Regime 2 is determined by the existence of strong turbulence that occurs when V>VT and is mainly driven by bulk shear.Regime 3 is identified by the existence of moderate turbulence when upside-down turbulence sporadic bursts occur in the presence of otherwise weak turbulence.Regime 4 is identified as buoyancy turbulence,when V>VT,and the turbulence regime is affected by a combination of local wind shear,bulk shear and buoyancy turbulence.The turbulence activities demonstrated a weak thermal stratification dependency in regime 1,for which within the UCL,the turbulence intensity was strongly affected by local wind shear when V<VT.This study further showed typical examples of different stable boundary layers and the variations between turbulence regimes by analyzing the evolution of wind vectors.Partly because of the influence of large-scale motions,the power spectral density of vertical velocity for upsidedown structure showed an increase at low frequencies.The upside-down structures were also characterized by the highest frequency of the stable stratifications in the higher layer.

Observed Vertical Structure of Precipitation over the Southeastern Tibetan Plateau in Summer 2021

Mêdog County,with its mountains and valleys,is located in the southeastern Tibetan Plateau(TP)and at the lower reaches of the Yarlung Zangbo River.This area has the highest annual rainfall amount over the TP,and in situ measurements are very scarce due to frequent debris flows and transportation difficulties.A monitoring campaign focused on cloud and precipitation observations was established in Mêdog in 2019 as a part of the Second Tibetan Plateau Scientific Expedition and Research Program.This paper evaluates the accuracy of micro rain radar(MRR)measurements and investigates the variations in precipitation vertical structure in Mêdog using observations collected from the MRR,disdrometer,and rain gauges in summer 2021.The measurements from the three instruments show a strong consistency,with correlation coefficients exceeding 0.93.Although the profiles of integral rain parameters for different rain rate categories in Mêdog are similar to those in other regions,the vertical evolution of raindrop size distributions shows significant differences.For lightest rain,the evaporation of small raindrops and breakup of large raindrops are clear during their descent.For the rainfall rate category of 0.2–2.0 mm h−1(2.0–20.0 mm h−1),concentrations of small and medium(large)drops show almost uniform vertical structures,while the large(medium)drop number displays a positive(negative)gradient.A disturbance at height of 1.5–2.0 km above ground level(AGL)is observed in the heavy rainfall due to strong updrafts.In general,the MRR measurements in Mêdog are robust.The raindrop breakup process is more apparent in Mêdog than in other regions,resulting in high concentration of sizelimited raindrops.In addition,it is found that the interaction between steep terrain and Mêdog convective rain causes the strong updrafts between 1.5 and 2.0 km AGL.

The vertical structure and seasonal changes of atmosphere ozone and temperature at Zhongshan Station over East Antarctica

The vertical structure of the atmospheric ozone and temperature as well as the seasonal variations is presented by using ozone sounding data at Zhongshan Station over East Antarctica from February, 2008 to February, 2009. The results show that the heights of thermal tropopause and ozone tropopause are mostly the same with yearly mean 7.9 and 7.4 km separately above the station. There is obvious seasonal variation in the pressure and temperature of the tropopause, manifested by the clear one-wave pattern with an opposite phase. As the turning point of the tropopause temperature is visible in autumn and faint in spring and winter, the tropopause height can be better confirmed by utilization of the changes of ozone. Seasonal variation of the tropospheric ozone of vertical distribution is not clear, relative to stratosphere. In the spring, ozone in the low level of stratosphere lost seriously. The minimum partial ozone in 14 km was 1.57 MPa only and the maximum partial ozone occurred in the up level stratosphere. In the rest of the season the ozone increases with height rising in the low level of stratosphere. The evidence shows that ozone lost in spring is closely related with low temperature of polar night and the process of PSC photochemical destruction ozone in the stratosphere. From the vertical characteristics and seasonal variation of ozone and temperature, it is meaningful to understand formation and development of Antarctic ozone deletion.

Impacts of Atmospheric Boundary Layer Vertical Structure on Haze Pollution Observed by Tethered Balloon and Lidar

In this paper, the characteristics of the atmospheric boundary layer(ABL) vertical structure over the North China Plain(NCP) during a comprehensive observation experiment conducted during 15–21 December 2018 were investigated. Observational data were obtained with a large tethered balloon, Doppler wind lidar, and ground-level instruments. The maximum concentration of PM_(2.5) exceeded 200 μg m^(-3), and the ratio of PM_(2.5)/PM_(10) was approximately 0.4(its maxi-mum was approximately 0.8) during the whole observation period, indicating the explosive growth of dominant fine-mode aerosols in the winter heating season. Elevated concentrations of pollutants decreased the solar irradiance received by the ground, resulting in lower temperature at ground level. Our results illustrate three distinct types of vertical profiles: Type 1(convective state)—the concentration of PM_(2.5) decreased nearly linearly with increase of the height below approximately 600 m;Type 2(stable state)—the PM_(2.5) concentration sharply decreased from the ground to approximately 200 m;and Type 3(multilayer structure)—some pollutants were suspended aloft in the upper air layer. Diurnal evolution of the vertical profiles of PM_(2.5) and their relationship with the changes in meteorological factors were identified. From daytime to nighttime, the vertical profiles evolved from Type 1 to Type 2 or Type 3. All the 33 vertical PM_(2.5) profiles that we obtained showed a strong relationship with elements of the ABL structure, such as the distributions of winds, the inversion layer, and turbulence activities. A light-wind layer and weak turbulence activity, especially within the inversion layer, contributed greatly to the accumulation of pollutants.Vertical PM_(2.5) concentration patterns were also greatly affected by local ground-level emission sources and regional transport processes.

Vertical Structures of Atmospheric Properties in Southeast Tibet during the South Asian Summer Monsoon in 2013

In June 2013,a field experiment was conducted in Southeast Tibet in which the air temperature,moisture,and wind were measured by using a GPS sounding system.In the present study,based on these observations and ERA-Interim reanalysis data,the vertical structures of these atmospheric properties and the possible influence of the South Asian summer monsoon（SASM） were investigated.On average,the temperature had a lapse rate of 6.8℃ km^（-1） below the tropopause of 18.0 km.A strong moisture inversion occurred at the near-surface,with a strength of 1.7 g kg^（-1）（100 m）^（-1） for specific humidity.During the observation period,the SASM experienced a south phase and a north phase in the middle and by the end of June,respectively.The monsoon＇s evolution led to large changes in convection and circulation over Southeast Tibet,which further affected the local thermal,moisture,and circulation conditions.The strong convection resulted in an elevated tropopause height over Southeast Tibet during the north phase of the SASM,and the large-scale warm and wet air masses delivered by the monsoon caused high local temperature and moisture conditions.

Plant Biodiversity and Structure of Robusta Coffee (Coffea canephora var. robusta) Agroforests in Cameroon

Agroforests are man-made ecosystems in which crops are associated with a main perennial species like Robusta Coffee Agroforests (RCAs), which is counted among the main modes of perennial crops production in Cameroon. Despite the rich ecosystem services provided, the diversity of Associated Species (AS) found in these RCAs and the structure of the landscapes they form remain little known in Cameroon. The current study aimed to inventory AS and characterize the structure of RCAs in four sites (Ayos, Malantouen, Melong and Nkongsamba) belonging to three robusta coffee production basins in Cameroon. A systematic inventory with dendrometric measurements of the wood AS and coffee trees was carried out on 120 one-hectare plot unit, i.e. 30 plots per site. The results showed that 102 AS belonging to 83 genera and 41 families were identified in these RCAs. The RCAs of Ayos in the dense rainforest zone with bimodal rainfall pattern were the most diverse with 71 species, followed by those of Melong and Nkongsamba with respectively 39 and 33 species respectively in the dense rainforest zone with monomodal rainfall pattern, and Malantouen with 33 species in the high savannahs of the west. Structurally, average coffee tree and AS densities founded ranged from 1208 - 1456 plants/ha and 71 - 214 stems/ha and those of basal area from 7.29 - 17.40 m2/ha for coffee trees and 7.97 - 16.14 m2/ha for AS in function of site. Basis on the vertical stratification, the proportion of the 3 - 6 m stratum, which is mainly represented by introduced AS, varied from 38% - 62% depending on the site. The results of this study showed that RCAs contribute to the conservation of plant biodiversity, given the specific richness identified in these ecosystems.

Reconstruction of vertical thermal structure from several subsurface temperatures in the China Seas and adjacent waters

Empirical Orthogonal Function （EOF） analysis is used in this study to generate main eigenvector fields of historical temperature for the China Seas （here referring to Chinese marine territories） and adjacent waters from 1930 to 2002 （510 143 profiles）. A good temperature profile is reconstructed based on several subsurface in situ temperature observations and the thermocline was estimated using the model. The results show that： 1） For the study area, the former four principal components can explain 95% of the overall variance, and the vertical distribution of temperature is most stable using the in situ temperature observations near the surface. 2） The model verifications based on the observed CTD data from the East China Sea （ECS）, South China Sea （SCS） and the areas around Taiwan Island show that the reconstructed profiles have high correlation with the observed ones with the confidence level 〉95%, especially to describe the characteristics of the thermocline well. The average errors between the reconstructed and observed profiles in these three areas are 0.69℃, 0.52℃ and 1.18℃ respectively. It also shows the model RMS error is less than or close to the climatological error. The statistical model can be used to well estimate the temperature profile vertical structure. 3） Comparing the thermocline characteristics between the reconstructed and observed profiles, the results in the ECS show that the average absolute errors are 1.5m, 1.4 m and 0.17~C/m, and the average relative errors are 24.7%, 8.9% and 22.6% for the upper, lower thermocline boundaries and the gradient, respectively. Although the relative errors are obvious, the absolute error is small. In the SCS, the average absolute errors are 4.1 m, 27.7 m and 0.007℃/m, and the average relative errors are 16.1%, 16.8% and 9.5% for the upper, lower thermocline boundaries and the gradient, respectively. The average relative errors are all 〈20%. Although the average absolute error of the lower thermocline boundary is considerable, but contrast to the spatial scale of average depth of the lower thermocline boundary （165 m）, the average relative error is small （16.8%）. Therefore the model can be used to well estimate the thermocline.

Identification of the sensitive area for targeted observation to improve vertical thermal structure prediction in summer in the Yellow Sea

The sensitive area of targeted observations for short-term(7 d)prediction of vertical thermal structure(VTS)in summer in the Yellow Sea was investigated.We applied the Conditional Nonlinear Optimal Perturbation(CNOP)method and an adjoint-free algorithm with the Regional Ocean Modeling System(ROMS).We used vertical integration of CNOP-type temperature errors to locate the sensitive areas,where reduction of initial errors is expected to yield the greatest improvement in VTS prediction for the selected verification area.The identified sensitive areas were northeast−southwest orientated northeast to the verification area,which were possibly related to the southwestward background currents.Then,we performed a series of sensitivity experiments to evaluate the effectiveness of the identified sensitive areas.Results show that initial errors in the identified sensitive areas had the greatest negative effect on VTS prediction in the verification area compared to errors in other areas(e.g.,the verification area and areas to its east and northeast).Moreover,removal of initial errors through deploying simulated observations in the identified sensitive areas led to more refined prediction than correction of initial conditions in the verification area itself.Our results suggest that implementation of targeted observation in the CNOP-based sensitive areas is an effective method to improve short-term prediction of VTS in summer in the Yellow Sea.

A study on the numerical prediction method for the vertical thermal structure in the Bohai Sea and the Huanghai Sea-I.One-dimensional numerical prediction model

In this paper, on the basis of the heat conduction equation without consideration of the advection and turbulence effects, one-dimensional model for describing surface sea temperature ( T1), bottom sea temperature ( Tt ) and the thickness of the upper homogeneous layer ( h ) is developed in terms of the dimensionless temperature θT and depth η and self-simulation function θT - f(η) of vertical temperature profile by means of historical temperature data.The results of trial prediction with our one-dimensional model on T, Th, h , the thickness and gradient of thermocline are satisfactory to some extent.

3D vertically aligned microchannel structure to enhance piezoelectric energy harvesting performance of PZT/PVDF&CNTs piezoelectric composites

Piezoelectric energy harvesters(PEHs)have attracted significant attention with the ability of converting mechanical energy into electrical energy and power the self-powered microelectronic components.Generally,material's superior energy harvesting performance is closely related to its high transduction coefficient(d_(33)×g_(33)),which is dependent on higher piezoelectric coefficient d33 and lower dielectric constantεr of materials.However,the high d33 and lowεr are difficult to be simultaneously achieved in piezoelectric ceramics.Herein,lead zirconate titanate(PZT)based piezoelectric composites with vertically aligned microchannel structure are constructed by phase-inversion method.The polyvinylidene fluoride(PVDF)and carbon nanotubes(CNTs)are mixed as fillers to fabricate PZT/PVDF&CNTs composites.The unique structure and uniformly distributed CNTs network enhance the polarization and thus improve the d33.The PVDF filler effectively reduce theεr.As a consequence,the excellent piezoelectric coefficient(d_(33)=595 pC/N)and relatively low dielectric constant(ε_(r)=1,603)were obtained in PZT/PVDF&CNTs composites,which generated an ultra-high d_(33)×g_(33) of 24,942×10^(−15) m^(2)/N.Therefore,the PZT/PVDF&CNTs piezoelectric composites achieve excellent energy harvesting performance(output voltage:66 V,short current:39.22μA,and power density:1.25μW/mm^(2)).Our strategy effectively boosts the performance of piezoelectric-polymer composites,which has certain guiding significance for design of energy harvesters.