Effect of sample temperature on femtosecond laser ablation of copper

We conduct an experimental study supported by theoretical analysis of single laser ablating copper to investigate the interactions between laser and material at different sample temperatures,and predict the changes of ablation morphology and lattice temperature.For investigating the effect of sample temperature on femtosecond laser processing,we conduct experiments on and simulate the thermal behavior of femtosecond laser irradiating copper by using a two-temperature model.The simulation results show that both electron peak temperature and the relaxation time needed to reach equilibrium increase as initial sample temperature rises.When the sample temperature rises from 300 K to 600 K,the maximum lattice temperature of the copper surface increases by about 6500 K under femtosecond laser irradiation,and the ablation depth increases by 20%.The simulated ablation depths follow the same general trend as the experimental values.This work provides some theoretical basis and technical support for developing femtosecond laser processing in the field of metal materials.

The Effect of Boreal Summer Intraseasonal Oscillation on Mixed Layer and Upper Ocean Temperature over the South China Sea

Intraseasonal oscillation of the mixed layer and upper ocean temperature has been found to occur over the South China Sea(SCS)in the summer monsoon season based on the multiple reanalysis and observational data in this study.The method of composite analysis and an upper ocean temperature equation assisted the analysis of physical mechanisms.The results show that the mixed layer depth(MLD)in the SCS has a significant oscillation with a 30-60 d period over the SCS region,which is closely related to boreal summer intraseasonal oscillation(BSISO)activities.The MLD can increase(decrease)during the positive(negative)phase of the BSISO and usually lags behind by approximately one-eighth of the lifecycle(5 days)of the BSISO-related convection.The BSISO may cause periodic anomalies at the air-sea boundary,such as wind stress and heat flux,so it can play a dominant role in modulating the variation in MLD.There also are significant intraseasonal seawater temperature anomalies in both the surface and subsurface layers of the SCS.In addition,during the initial phase of the BSISO,the temperature anomaly signals of the thermocline are obviously opposite to the sea surface temperature(SST),especially in the southern SCS.According to the results from the analysis of the temperature equation,the vertical entrainment term caused by BSISO-related wind stress is stronger than the thermal forcing during the initial stage of convection,and it is more significant in the southern SCS.

Effect of temperature,salinity and irradiance on growth and photosynthesis of Ulva prolifera

Intensive Pyropia aquaculture in the coast of southwestern Yellow Sea and its subsequent waste, including disposed Ulva prolifera, was speculated to be one of the major sources for the large-scale green tide proceeding in the Yellow Sea since 2007. It was, however, unclear how the detached U. prolifera responded and resumed growing after they detached from its original habitat. In this study, we investigated the growth and photosynthetic response of the detached U. prolifera to various temperature, salinity and irradiance in the laboratory. The photosynthetic rate of the detached U. prolifera was significantly higher at moderate temperature levels（14–27℃）and high salinity（26–32）, with optimum at 23℃ and 32. Both low（14℃） and highest temperature（40℃）, as well as low salinity（8） had adverse effects on the photosynthesis. Compared with the other Ulva species, U. prolifera showed higher saturated irradiance and no significant photoinhibition at high irradiance, indicating the great tolerance of U. prolifera to the high irradiance. The dense branch and complex structure of floating mats could help protect the thalli and reduce photoinhibition in field. Furthermore, temperature exerted a stronger influence on the growth rate of the detached U. prolifera compared to salinity. Overall, the high growth rate of this detached U. prolifera（10.6%–16.7% d^–1） at a wide range of temperature（5–32℃） and salinity（14–32） implied its blooming tendency with fluctuated salinity and temperature during floating. The environmental parameters in the southwestern Yellow Sea at the beginning of green tide were coincident with the optimal conditions for the detached U. prolifera.

Low Root Zone Temperature Exacerbates the Ion Imbalance and Photosynthesis Inhibition and Induces Antioxidant Responses in Tomato Plants Under Salinity

The combined effects of salinity with low root zone temperature （RZT） on plant growth and photosynthesis were studied in tomato （Solanum lycopersicum） plants. The plants were exposed to two different root zone temperatures （28/20℃, 12/8℃, day/night temperature） in combination with two NaC1 levels （0 and 100 mmol L-l）. After 2 wk of treatment, K＋ and Na~ concentration, leaf photosynthetic gas exchange, chlorophyll fluorescence and leaf antioxidant enzyme activities were measured. Salinity significantly decreased plant biomass, net photosynthesis rate, actual quantum yield of photosynthesis and concentration of K＋, but remarkably increased the concentration of Na＋. These effects were more pronounced when the salinity treatments were combined with the treatment of low RZT conditions. Either salinity or low RZT individually did not affect maximal efficiency of PSII photochemistry （Fv/Fm）, while a combination of these two stresses decreased Fv/Fm considerably, indicating that the photo-damage occurred under such conditions. Non-photochemical quenching was increased by salt stress in accompany with the enhancement of the de-epoxidation state of the xanthophyll cycle, in contrast, this was not the case with low RZT applied individually. Salinity stress individually increased the activities of SOD, APX, GPOD and GR, and decreased the activities of DHAR. Due to the interactive effects of salinity with low RZT, these five enzyme activities increased sharply in the combined stressed plants. These results indicate that low RZT exacerbates the ion imbalance, PSII damage and photosynthesis inhibition in tomato plants under salinity. In response to the oxidative stress under salinity in combination with low RZT, the activities of antioxidant enzymes SOD, APX, GPOD, DHAR and GR were clearly enhanced in tomato plants.

Effects of Salinity and Temperature on Growth and Survival of Juvenile Iwagaki Oyster Crassostrea nippona

Iwagaki oyster Crassostrea nippona occurs naturally along the coasts of Japan and Korea. Because of its unique flavor, delicious taste, edibility during the summer and high commercial value, it has been identified as a potential aquaculture species. To determine the optimum aquaculture conditions and provide necessary information for mass production of the juvenile, the effects of six salinities(15, 20, 25, 30, 35 and 40) and five temperatures(16, 20, 24, 28 and 32℃) on growth and survival of juvenile C. nippona were examined in this study. In the salinity experiment, the largest values of mean shell height and growth rate were observed at salinity 25(20.96 ± 0.36 mm and 172.0 μm d^(-1), respectively), which were significantly different(P < 0.05) with those of other treatments, except at salinity 30(20.56 ± 1.05 mm and 160.3 μm d^(-1), respectively)(P > 0.05). The maximum survival rate 84.44% was always observed at salinity 20, and there was no significant difference(P > 0.05) in survival rate among salinities varying between 15 and 35. In the temperature-related experiments, the highest growth and survival rates of juvenile were observed at 24℃(180.8 μm d^(-1) and 84.4%) and 28℃(190.7 μm d^(-1) and 83.3%), respectively, on day 20, and showed significantly(P < 0.05) larger size and higher survival rate than any other groups. Both juvenile survival and growth were significantly depressed at extreme salinities(15, 40) and temperatures(16℃, 32℃). Based on the results of the present study, a salinity range from 25 to 30 and a temperature range from 24℃ to 28℃ are considered optimal conditions for survival and growth of juvenile C. nippona.

Analysis on Features of Temperature and Salinity in the Northern Taiwan Straits During February-March, 1998

The distributional features of temperature and salinity in the northern Taiwan Straits have been analyzed based on the CTD data during February-March, 1998. The characteristics of temperature and salinity are summarized as follows: (1) there exists a coastal water along the western coast of the Taiwan Straits, with low temperature and low salinity at the upper layer; (2) a high temperature and high salinity water tongue extends northeastward along the eastern coast of the Taiwan Strait.

Observed features of temperature, salinity and current in central Chukchi Sea during the summer of 2012

During the summer of 2012, the fifth CHINARE Arctic Expedition was carried out, and a submersible mooring system was deployed in M5 station located at （69°30.155＇N,169°00.654＇W） and recovered 50d later. A set of temperature, salinity and current profile records was acquired. The characteristics of these observations are analyzed in this paper. Some main results are achieved as below. （1） Temperature generally decreases while salinity generally increases with increasing depth. The average values of all records are 2.98℃ and 32.21 psu. （2） Salinity and temperature are well negatively correlated, and the correlation coefficient between them is -0.84. However, they did not always vary synchronously. Their co-variation featured different characters during different significant periods. （3） The average velocity for the whole water column is 141 mm/s with directional angle of 347.1°. The statistical distribution curve of velocity record number gets narrower with increasing depth. More than 85% of the recorded velocities are northward, and the mean magnitudes of dominated northward velocities are 100-150 mm/s. （4） Rotary spectrum analysis shows that motions with low frequency take a majority of energy in all layers. The most significant energy peaks for all layers are around 0.012 cph （about 3.5 d period）, while the tidal motion in mooring area is nonsignificant. （5） Velocities in all layers feature similar and synchronous temporal variations, except for the slight decrease in magnitude and leftward twist from top to bottom. The directions of velocity correspond well to those of Surface wind. The average northward volume transport per square meter is 0.1-0.2 m3/s under southerly wind, but about -0.2 m3/s during northerly wind burst.

Effects of temperature and salinity on the asexual reproduction of Aurelia coerulea polyps

Aurelia coerulea polyp is an important stage in the outbreaks of this species.To test the combined effects of salinity and temperature on the survival and asexual reproduction of polyps,we maintained 864 polyps at various salinities(15,25,33,and 40)and temperatures(9,12,15,18,21,and 24℃).Polyps could mostly survive in all treatment combinations except in salinity 15 treatments with low temperatures(9-15℃).Budding occurred at all temperatures(9-24℃),while strobilation only occurred at the low temperatures(9-15℃).The range of 12-15℃was suitable for strobilation and ephyrae release.The optimal range of salinity for asexual reproduction was 25-33.Low(15)or high(40)salinity could significantly reduce the numbers of new buds or ephyrae,and low salinity of 15 retarded and even prevented strobilation at low temperatures.The optimal treatment for budding and strobilation was 21℃-salinity 25 and 12℃-salinity 33,respectively.Salinity had less of an impact than temperature on asexual reproduction,except for the polyps in high or low osmotic pressure conditions.

Distributional features of temperature and salinity in the southern Taiwan Strait and its adjacent sea areas in late summer, 1994

Based on the CTD data obtained in the southern Taiwan Strait and its adjacent areas in August and September of 1994, the distributional features of the temperature and salinity in the studied area have been analyzed in detail. The results are as follows: (1) There are two low temperature and high salinity regions in the nearshore area between Dongshan and Shantou and in the southeastern Taiwan Shoal, respectively, which may be caused by upwellings. (2) There exists a cold eddy in the northwestern sea area and a warm eddy with two high temperature cores in the eastern sea area of the Dongsha Islands, which are related to the anti-cyclonic turning of the seawater near the Dongsha Islands. (3) A westward high temperature and high salinity water tongue extends through the northern Luzon Strait and reaches the sea areas near the Dengsha Islands and southern Taiwan Strait.

Vertical properties of nutrients and oxygen under temperature-salinity structure of the Bering Basin in July 1999

The China R/V Xuelong went on the first Arctic scientific cruise, and we obtained 271 hydro-chemical samples from 22 deep-sea stations in the Bering Basin in late July, 1999. Here we describe vertical properties of silicate [Si] , dissolved inorganic nitrogen [DIN] or [N] (nitrate plus ammonium plus nitrite) , phosphate [P] and oxygen [ O2 ] in seawater under potential temperature-salinity structure. The seasonal stratification in the summer and the water exchanges of the North Pacific Ocean over the Bering Basin resulted in that the four layers of vertical structure with two thermoclines may be found. Vertical [Si] and [N] and [P] profiles show that the nutrients are consumed mainly in ≤50 m and the order of deficient nutrients is [Si] the first, [N] the second and [P] the third. The [N] and [P] increase with depth downward to about 500 m and then both decrease, but the [Si] increases from 150 m to 2000 m or the bottom. In ≥ 150 m the [ O2 ] decreases, which is related with both [P] and [N] increasing closely. Seawater [N] :[P] ratios are 6 - 12 in =≤50 m, 10.5 - 14.3 in 100 - 150 m and 11.7 - 15.8 from 300 m to the bottom.

Carbon nanotube enhanced water-based drilling fluid for high temperature and high salinity deep resource development

Drilling fluids face failure during drilling deep reservoir with high temperature and high salt.The experimental results show that high temperature and salinity reduce the negative charge on the surface of bentonite in the drilling fluid and cause the coalescence of bentonite particles.As a result,the particles coalesce,the grid structure is destroyed,and the rheological properties,rock-carrying capacity and filtration properties are lost.To resolve the foregoing,in this study,0.05-wt%carbon nanotubes are introduced into a 4%bentonite drilling fluid under conditions where the temperature and concentration of added Na Cl reach 180°C and 10 wt%,respectively.The carbon nanotubes adsorb on the bentonite surface and increase the space among bentonite particles.The steric hindrance prevents the coalescence of bentonite in high temperature and high salt environment.Thus bentonite maintains the small size distribution of bentonite and supports the bentonite grid structure in the drilling fluid.As a result,the rock-carrying capacity of the drilling fluid increases by 85.1%.Moreover,the mud cake formed by the accumulation of small-sized bentonite particles is dense;consequently,the filtration of bentonite drilling fluid reduced by 30.2%.

Effects of Temperature and Salinity on Oxygen Consumption and Ammonium Excretion Rate of ♀ Epinephelus fuscoguttatus × ♂ E. lanceolatus Juveniles

The impact of water temperature(24, 27, 30 and 33℃) and salinity(15, 20, 25, 30 and 33) on oxygen consumption(OCR) and ammonium excretion rate(AER) of ♀ Epinephelus fuscoguttatus ×♂ E. lanceolatus hybrid grouper juveniles(9.39 ± 0.07 g) were investigated under the fed and un-fed conditions. The results showed that the OCR and AER were significantly(P < 0.05) affected by temperature and salinity under both fed and un-fed conditions. When temperature was 24–33℃, the OCR and AER of fed hybrid grouper juveniles were 85.68%–129.52% and 125.78%–287.63%, respectively, higher than those of un-fed hybrid grouper juveniles. The O/N ratio, protein use(P_u), Q_(10)(respiration) and Q_(10)(excretion) of fed hybrid grouper juveniles were 14.43–24.01, 28.35% – 48.48%, 1.69 and 3.01, respectively. The O/N ratio, P_u, Q_(10)(respiration), Q_(10)(excretion) of un-fed hybrid grouper juveniles were 20.39 – 31.79, 22.16% – 34.34%, 1.23 and 1.17, respectively. When salinity was 15–33, the OCR and AER of fed hybrid grouper juveniles increased by 87.42% – 116.85% and 215.38% – 353.57%, respectively, over those of un-fed hybrid grouper juveniles. The O/N ratio and P_u of fed hybrid grouper juveniles were 14.48 – 17.78, 39.36% – 49.43%, respectively. The O/N ratio and Pu of un-fed hybrid grouper juveniles were 20.39 – 31.79 and 22.16% – 34.34%, respectively. The specific dynamic action(SDA) of hybrid grouper juveniles was mainly related to protein metabolism. The results had a guiding significance to the large-scale intensive aquaculture of hybrid grouper juveniles.

Variations of temperature, salinity and current in the southern tidal passage of the Hangzhou Bay, China

Field surveys covering a spring-neap tidal period were conducted to investigate the characteristics of tidal dynamics within a curved channel in the southern Hangzhou Bay, China. The channel has a maximum depth of more than 100 m with an average tidal range of 2.5 m, serving as the main tidal passage in the southern part of the Hangzhou Bay. Water salinity, temperature and velocity data were collected from the ship-based transects and mooring measurements. During flood tide, the tidal current intrudes into the Hangzhou Bay through the northern side of the channel with a maximum velocity of about 2 m/s, while retreats through the southern side during ebb tide with a maximum velocity of 1.8 m/s. Due to the pressure, density gradients, the Coriolis force and centrifugal effect, a lateral exchange flow is generated as the tidal current relaxes from flood to ebb. Salinity and temperature data show that the water in the channel is weakly stratified during both spring and neap tides in summer time.However, mixing in the middle region will be enhanced by the lateral circulation. Mooring data indicate that the temperature and salinity are varying at a frequency similar to tidal current but higher than sea level oscillation.Our results support the hypothesis that the high frequency salinity and temperature variations could be generated by combination of the tidal current and the lateral exchanging flow.

Sectional characteristics of temperature, salinity and density off the central Zhejiang coast in the spring of 2016

In this study, the sectional characteristics of temperature, salinity and density off the central Zhejiang coast were analyzed using three sections of observational data in the spring of 2016. The results are as follows:(1) a cold water patch was observed in the middle layer of sections from 10 to 25 m, and a weak upwelling was observed at the upper layer near the central Zhejiang coast;(2) several thermoclines, inverted thermoclines, and haloclines were observed in the survey area;(3) the Taiwan Warm Current Water(TWCW) climbing from the slope towards the survey area affected the thermocline, making it thinner and intensified; however, the TWCW was not strong enough to break through the thermocline to reach the sea surface.

Refined Modeling of Water Temperature and Salinity in Coastal Areas

The prediction of water temperature and salinity in coastal areas is one of the essential tasks in water quality control and management. This paper takes a refined forecasting model of water temperature and salinity in coastal areas as a basic target. Based on the Navier-Stokes equation and k-epsilon turbulence model, taking the characteristics of coastal areas into account, a refined model for water temperature and salinity in coastal areas has been developed to simulate the seasonal variations of water temperature and salinity fields in the Hakata Bay, Japan. The model takes into account the effects of a variety of hydrodynamic and meteorological factors on water temperature and salinity. It predicts daily fluctuations in water temperature and salinity at different depths throughout the year. The model has been calibrated well against the data set of historical water temperature and salinity observations in the Hakata Bay, Japan.

Effects of Temperature,Salinity and Stocking Density on Larval Survival and Growth of Reciprocal Crosses Between Two Strains of Pacific Oysters,Crassostrea gigas

The Pacific oyster Crassostrea gigas is one of the most widely cultivated aquaculture species and contributes signifi-cantly to total seafood production for human beings.However,mass mortality occurred frequently,and in some regions almost all oysters died during seed production and grow-out stage.In order to explore whether hybridization breeding can improve its growth and survival,a complete diallel cross between a selected strain‘Haida No.1’(S)and an orange shell variant(O)of C.gigas was carried out.The larval growth and survival were compared among hybrids and purebred strains at temperatures of 16,20,24,28 and 32℃;salinities of 15,20,25,30 and 35;and stocking densities of 0.5,1,2,4 and 8 larvae mL−1.Under different environments,the hybridization between two strains of C.gigas showed the heterosis of growth and survival.The mean shell height and survival rate of the two reciprocal crosses(OS,SO)were significantly higher than those of the two purebred strains(SS,OO)under all environ-mental conditions.In particular,OS showed greater heterosis than the purebred strains and SO progeny.The results showed that the productive traits of the‘Haida No.1’could be improved by crossing with the orange shell line.Meanwhile,the results from this study also indicated that hybridization between the two strains of C.gigas may be a promising way for breeding new variety with high survival rate.

A novel polymer gel with high-temperature and high-salinity resistance for conformance control in carbonate reservoirs

Plugging agents have been widely used to enhance oil recovery in fractured-vuggy carbonate reservoirs.However,the harsh conditions of fractured-vuggy carbonate reservoirs yield a significant challenge in maintaining a long-term stabilization of plugging agents.In this work,we developed an anti-hightemperature and high-salinity polymer gel(APG)with excellent resistance to high temperature(140℃)and ultra-high salinity(240000 mg/L).The rheology and microstructure of APG were characterized before and after gelation.Core plugging tests on fractured cubic cores were conducted to quantify the plugging performance of the gel system.Experimental results showed that the Sclerglucan and Cobalt(Ⅱ)Chloride Hexahydrate filled the three-dimensional(3-D)network with various morphologies,providing extra protection to the cross-linking points of the 3D network structure of APG and thus,leading to a prolongation of the dehydration time.The dehydration rate of APG was only 5%within 30days,and the strength of APG could be maintained at a rigid or near-rigid level over 150 days.Moreover,APG exhibited satisfactory shear and scour resistance.Core plugging tests showed that APG could achieve a plugging rate of 90%and demonstrate ignorable minor damage to the substrate.Our results indicate that APG can serve as a great candidate in channel plugging in fractured-vuggy carbonate reservoirs where fractures are fully developed.

Enhanced Biodegradation of High-Salinity and Low- Temperature Crude-Oil Wastewater by Immobilized Crude-Oil Biodegrading Microbiota

High salt and low temperature are the bottlenecks for the remove of oil contaminants by enriched crude-oil degrading microbiota in Liaohe Estuarine Wetland(LEW),China.To improve the performance of crude-oil removal,microbiota was further immobilized by two methods,i.e.,sodium alginate(SA),and polyvinyl alcohol and sodium alginate(PVA+SA).Results showed that the crude oil was effectively removed by the enrichment with an average degrading ratio of 19.42-31.45 mg(L d)^(−1).The optimal inoculum size for the n-alkanes removal was 10%and 99.89%.Some members of genera Acinetobacter,Actinophytocola,Aquabac-terium,Dysgonomonas,Frigidibacter,Sphingobium,Serpens,and Pseudomonas dominated in crude-oil degrading microflora.Though the removal efficiency was lower than free bacteria when the temperature was 15℃,SA and PVA+SA immobilization im-proved the resistance to salinity.The composite crude-oil degrading microbiota in this study demonstrated a perspective potential for crude oil removal from surface water under high salinity and low temperature conditions.

The combined effects of temperature and salinity on survival of postlarvae tiger prawn <i>Penaeus monodon</i>under laboratory conditions

A 3 x 4 two-factor factorial experimental design with three replications per treatment was conducted to determine the effects three temperatures viz., room temperature (29°C ± 1°C) and elevated temperatures (33°C and 35°C ± 0.5°C) and four salinities (25, 30, 33 and 35 ppt) on survival of postlarvae tiger prawn Penaeus monodon under laboratory conditions. Results showed that temperature had a greater influence on survival of postlarvae P. monodon than salinity and low water temperature (29°C) gave better larval survival than higher water temperatures (33°C and 35°C). In addition, the PL1 had better tolerance to high temperatures than PL15. At the termination of the experiment, the best survival of PL1 was found at 29°C for all salinities tested with an average of 95.8%, while the best survival of PL15 was also found at 29°C for all salinities tested with an average of 70.6%. Based on survival at temperatures and salinities tested, the best salinity and temperature combination for the culture of P. monodon PL1 and PL15 were 29°C at 25, 30, 33 and 35 ppt, and 29°C at 25 and 30 ppt, respectively.

The Coupled Effect of Temperature Changes and Damage Depth on Natural Frequencies in Beam-Like Structures

A significant amount of research is concerned with dynamic modal parameters for damage detection of structural conditions due to their simplicity in use and feasibility.However,their use for damage detection should be performed with special attention,particularly in operational and environmental conditions subjected to temperature changes.Beams in construction industries experience different loading types,such as temperature changes leading to crack initiation and propagation.Changed physical and dynamic properties such as natural frequencies and mode shapes indicate that damage has occurred within the structures.In this study,vibration analysis of cantilever and cantilever simply supported beams has been carried out on intact and damaged beams to investigate the coupled effect of temperature changes and damage depth on natural frequencies.A numerical analysis of beams is completed using ANSYS software.The results of numerical simulation are validated using two other studies from literature.Numerical results revealed that in order to perform a successful damage assessment using the frequency shift,the vibration modes should be selected properly.In addition,an increase in temperature results in a decrease in structural frequencies.The assessment of the effect of damage depth on natural frequencies also confirms that when damage depth is increased,there is a significant decrease in natural frequency responses.