Effect of heating time on structural,morphology,optical,and photocatalytic properties of g-C3N4 nanosheets

Effect of heating time on the structural,morphology,optical,and photocatalytic properties of graphitic carbon nitride(g-C3N4)nanosheets prepared at 550℃in Ar atmosphere is studied.The investigations are carried out by using x-ray diffraction(XRD),scanning electron microscopy(SEM),Fourier-transform infrared spectroscopy(FTIR),UV-vis absorption,and photoluminescence(PL).At a heating temperature of 550℃,g-C3N4 nanocrystals are formed after 0.5 h and become more orderly as the heating time increases.The surface area of the g-C3N4 nanosheets significantly increases as the preparation time increases.The g-C3N4 prepared in 2.5 h shows the highest photocatalytic performance,decomposing completely 10 ppm RhB solution under xenon lamp irradiation for 2.0 h.

Influence of synthetic temperature and heating time on the luminescence behavior of M_5(PO_4)_3Cl:Eu^(2+),Mn^(2+)(M=Ca, Sr) phosphors

To further understand the energy loss mechanism of the ＂charge transfer process＂ that was proposed in our previous work on Eu^2＋-Mn^2＋ co-doped phosphors, the influence of synthetic temperature and heating time on the photoluminescence（PL） behavior of M5（PO4）3Cl：Eu^2＋,Mn^2＋（M=Ca, Sr） phosphors was investigated by analyzing their PL spectra and decay curves. For the Ca phase, an increase in the synthetic temperature resulted in an increase in the loss from the ＂charge transfer process＂ since more Eu^2＋ ions were involved in the Eu^2＋-Mn^2＋ clusters. This was contrary to the thermodynamic expectation. To solve this contradiction, we proposed that the formation of Eu^2＋-Mn^2＋ clusters was kinetically blocked at lower synthetic temperatures. With an increase in heating time for the phosphors synthesized at lower temperature（such as 1100 ℃） the PL intensity decreased, which supported the above assertion.

Effect of Glycerol Concentration and Heating Treatment on Delignification and Bioethanol Production of Sago Dregs

The purpose of this paper was to find the suitable condition between glycerol concentration and heating time treatment in the process of delignification and bioethanol production. The production of bioethanol consisted of 3 main stages： hydrolysis, fermentation, and distillation. The best result was obtained by a glycerol concentration of 90% and 15 minutes of heating time. It was used to delignify the lignocellulose biomass waste of the sago dregs originally containing 36.56% of lignin, 37.6% of or-cellulose and 39.51% of holocellulose. Then after being delignificated by 90% of glycerol concentration with 15 minutes heating time, the lignin content decreased to 19.3%, while a-cellulose increased to 39.64% and holocellulose also increased to 62.18%. After the delignification was successful, it was followed by the bioethanol production to produce 25% of bioethanol. This research is expected to overcome the problem of the energy crisis, food crisis, and environmental pollution by the sago dregs.

Effects of Heating Rate on the Process Parameters of Superplastic Forming for Zr_(55)Cu_(30)Al_(10)Ni_5

We investigated the effects of heating rate on the process parameters of superplastic forming for Zr55Cu30Al10Ni5 by differential scanning calorimetry. The continuous heating and isothermal annealing analyses suggested that the temperatures of glass transition and onset crystallization are heating rate-dependent in the supercooled liquid region. Then, the time-temperature-transformation diagram under different heating rates indicates that increasing the heating rate can lead to an increase of the incubation time at the same anneal temperature in the supercooled liquid region. Based on the Arrhenius relationship, we discovered that the incubation time increases by 1.08-1.11 times with double increase of the heating rate at the same anneal temperature, and then verified it by the data of literatures and the experimental results. The obtained curve of the max available incubation time reveals that the incubation time at a certain anneal temperature in the supercooled liquid region is not infinite, and will increase with increasing heating rate until this temperature shifts out of the supercooled liquid region because of exceeding critical heating rate. It is concluded that heating rate must be an important processing parameter of superplastic forming for Zr55Cu30Al10Ni5.

Heat Saturation Time of Solid Spherical Regenerator of HTAC

In order to control the heat saturation time, the temperature field of the regenerators of high temperature air combustion （HTAC） technology after reheating furnace was studied. A one-dimensional unsteady mathematical model was established and discretized through finite difference method. The relationship between the heat saturation time and some factors was determined through the calculation of a program developed by language C. The heat saturation time decreases with the increase of heat convection coefficient, however, the increase of heat capacity, density and radius of regenerator all increase the heat saturation time approximately linearly.

Development of inclusions in 3104 alloy melt during heating and holding treatments

Developments in the contents of different typical inclusions in 3104 alloy melt were described during heating and holding processing. The settling process of inclusion particles was investigated by measuring the contents of inclusions in the surface, center, and bottom layers of the molten metal. In the results, main inclusions observed and determined by Prefil and PoD FA methods are MgO, Al2O3, spinel（MgAl2O4）, and TiB2 particles or thin films. It is found that some small particles of Al2O3 and MgO are transformed into spinel particles, and the formation rate increases as the temperature and the holding period of melt increase. The content of inclusions increases from 3.37 mm^2×kg^-1 to 7.54 mm^2×kg^-1 and then decreases to 3.08 mm^2×kg^-1 after holding for 90 min. This is attributed to a settling phenomenon and a significant increase in settling velocity after holding for 60 min. The content of inclusion particles decreases by means of settlement and flotation in liquid aluminum with an increase in holding time. The theoretical analysis and experiment results are in essential agreement with those from industrial production.

Investigation on influencing factors of 5-HMF content in Schisandra

In order to investigate the influencing factors of 5-hydroxymethyl-2-furaldehyde （5-HMF） content in Schisandra, confirm the theory of 5-HMF deriving mainly from Schisandra processing course, and give some suggestions about the Schisandra processing method, the 5-HMF contents in decoctions of Schisandra under different heating temperature, decocting time, soaking time, processing methods and treatment with different solvents before decocting the Schisandra were measured by RP-HPLC method. The results showed that there is great difference of 5-HMF level in decoctions from differently processed Schisandra and unprocessed Schisandra; decocting time of 60 rain has some effects on 5-HMF level in decoctions and there is certain quantity 5-HMF in processed Schisandra itself and very little 5-HMF in unprocessed Schisandra. Heating time, heating temperature and treating solvents all have effect on 5-HMF level in decoction of Schisandra. 5-HMF in Schisandra was mainly from processing course. Both long heating time and high heating temperature can increase 5-HMF level in Schisandra. The production of 5-HMF in Schisandra may have some relationships with some polar components, which can dissolve in water, ethanol and acetone, especially in ethanol. To control processing temperature, processing time and treatment with some solvent is very important for controlling 5-HMF level in Schisandra.

Study of Frequency Effects on Hardness Profile of Spline Shaft Heat-Treated by Induction

This paper is devoted to the study of frequency effects on hardness profile of AISI 4340 spline shaft heat-treated by induction through an extensive 3D finite element method simulation and structured experimental investigation. Based on coupled electromagnetic and thermal fields analysis, the 3D model is used to estimate the temperature distribution and the hardness profile. The proposed study examines the hardening process parameters, such as frequency, induced current density and heating time, known to have an influence on hardened surface and builds the simulation model step by step. The established model can provide not only an accurate prediction of temperature distribution and hardness profile but also a comprehensive analysis of machine parameters effects, especially the frequency. The numerical results achieved by this model are good and present a great agreement to the experimental data.

Numerical prediction of the long- term soil temperature variations around shallowsections of cross-river road tunnels

Considering the coupled heat transfer effect induced by parallel cross-river road tunnels, the long-term soil temperature variations of shallow sections of cross-river tunnels under the river beach are predicted using the finite difference method for numerical simulation. The boundary conditions and the initial values are determined by in situ observations and numerical iterations.The simulation results indicate that the ultimate calculated steady heat transfer time is 68 years, and most of the heat transfer is completed in 20 years.The initial constant temperature soil surrounding the tunnels is transformed to an annually variable one.An obvious temperature-varying region of the surrounding soil is discovered within 5 m from the tunnel exterior, as well as within the entire range of soil between the two tunnels.The maximum temperature increase value reaches 7.14 ℃ and the maximum peak-to-valley value of annual temperature increase reaches 10 ℃.The temperature variation of soils surrounding tunnels below 10 m is completely controlled by the heat transfer from the tunnels.The coupled heat transfer effect is confirmed because the ultimate steady temperature of soil between the two tunnels is higher than the ones along other positions.Moreover, the regression model comprising a series of univariate functions is proposed for the annual soil temperature fluctuation estimation for the locations varied distances around the tunnel.This investigation is beneficial to gain an insight into the long-term variation tendencies of local engineering geological conditions of the river beach above shallow sections of the cross-river road tunnels.

Discussion on design for alkaline cleaning system of continual annealing line

Conventional process flow and main work mechanism of alkaline cleaning process of Continual Annealing Line are generally reviewed in the paper,and the work flow of design is analysed including the lye,rinse water circuit,conductivity detection circuit,utility media supply circuit and other main working circuits.Meanwhile,the heat demand of the alkaline cleaning system,rinse water system and dryer device are also analysed.Lumped parameter method in the heat-transfer theory is adopted to calculate the heating time of unsteady heat transfer for strips in the on-line tank.And the reasons why brush roller is of inverse brush and rinsing nozzles are equipped at the inlet side are found.Types and working principles of iron removal and degreasing devices for alkaline cleaning system,which adopt new magnetic filtration and ultra filtration processes,are described.Besides,the bypass filtering method is used to calculate the processing capacity of magnetic filtration and ultra filtration devices.Finally,the related features of 3-Dimension software "PlantSpace" for designing a CAL in Baosteel are totally introduced,such as specification for piping,co-designing,pipe code and 3-Dimension design process.

Shock tube study of n-decane ignition at low pressures

Ignition delay times for n-decane/O2/Ar mixtures were measured behind reflected shock waves using endwall pressure and CH＊ emission measurements in a heated shock tube. The initial postshock conditions cover pressures of 0.09-0.26 MPa, temperatures of 1 227-1 536 K, and oxygen mole fractions of 3.9%-20.7% with an equivalence ratio of 1.0. The correlation formula of ignition delay dependence on pressure, temperature, and oxygen mole fraction was obtained. The current data are in good agreement with available low-pressure experimental data, and they are then compared with the prediction of a kinetic mechanism. The current measurements extend the kinetic modeling targets for the n-decane combustion at low pressures.

Preparation and characterization of Sr0.5Ba0.5Nb2O6 glass-ceramic on piezoelectric properties

We studied the influence of heat treatment time on the optical, thermal, electrical, and mechanical properties of stron- tium barium niobate （Srl-xBaxNb206; hereafter SBN） piezoelectric glass-ceramics with tungsten bronze-type structure, which have good piezoelectric properties and are important lead-free piezoelectric materials. We found that the best heat treatment time is 4 h. The properties of the prepared materials are better than that of SBN ceramics and the glass-ceramic growth is faster than the SBN crystal when the heat treatment time of the SBN piezoelectric glass-ceramic is controlled, reducing the preparation costs greatly.

Temperature Distribution and Heat Saturating Time of Regenerative Heat Transfer

In this paper, heat transfer of the ceramic honeycomb regenerator was numerically simulated based on the computational fluid dynamics numerical analysis software CFX5. The longitudinal temperature distribution of regenerator and gas were obtained. The variation of temperature with time was discussed. In addition, the effects of some parameters such as switching time, gas temperature at the inlet of regenerator, height of regenerator and specific heat of the regenerative materials on heat saturating time were discussed. It provided primarily theoretic basis for further study of regenerative heat transfer mechanism.

Effect of Heat Treatment Time on Dy–Cu Alloy Diffusion Process in Dy-Containing Commercial Nd–Fe–B Sintered Magnets

In this paper, the grain boundary diffusion process（GBDP） using a Dy70Cu30（at.%） alloy as the diffusion source was performed in a commercial sintered Nd–Fe–B magnet, and the effect of heat treatment time on the microstructure and magnetic properties of the magnet was investigated in detail. For the processed magnets heat-treated at 860℃, as heat treatment time increased, the coercivity and the depth of（Nd,Dy）2Fe14B core–shell structure increased first and then decreased. However, when the heat treatment time was more than 2 h, the diffusion path of Dy from the Dy-rich shell phase into the Nd2Fe14B grains was revealed, and a nearly homogeneous（Nd,Dy）2Fe14B phase was formed, which brought on the decrease in both the depth of visible core–shell structure and the coercivity of Nd–Fe–B magnet.

Comparative assessment of the thermal tolerance of spotted stemborer, Chilo partellus （Lepidoptera： Crambidae） and its larval parasitoid, Cotesia sesamiae （Hymenoptera： Braconidae）

Under stressful thermal environments, insects adjust their behavior and physi- ology to maintain key life-history activities and improve survival. For interacting species, mutual or antagonistic, thermal stress may affect the participants in differing ways, which may then affect the outcome of the ecological relationship. In agroecosystems, this may be the fate of relationships between insect pests and their antagonistic parasitoids un- der acute and chronic thermal variability. Against this background, we investigated the thermal tolerance of different developmental stages of Chilo partellus Swinhoe （Lepi- doptera： Crambidae） and its larval parasitoid, Cotesia sesamiae Cameron （Hymenoptera： Braconidae） using both dynamic and static protocols. When exposed for 2 h to a static temperature, lower lethal temperatures ranged from -9 to 6 ℃, -14 to -2 ℃, and -1 to 4 ℃ while upper lethal temperatures ranged from 37 to 48 ℃, 41 to 49 ℃, and 36 to 39 ℃ for C partellus eggs, larvae, and C. sesamiae adults, respectively. Faster heating rates improved critical thermal maxima （CTmax） in C partellus larvae and adult C partel- lus and C sesamiae. Lower cooling rates improved critical thermal minima （CTmin） in C partellus and C. sesamiae adults while compromising CTmin in C. partellus larvae. The mean supercooling points （SCPs） for C. partellus larvae, pupae, and adults were -11.82 ± 1.78, -10.43 ±1.73 and -15.75 ±2.47, respectively. Heat knock-down time （HKDT） and chill-coma recovery time （CCRT） varied significantly between C partellus larvae and adults. Larvae had higher HKDT than adults, while the latter recovered significantly faster following chill-coma. Current results suggest developmental stage differences in C partellus thermal tolerance （with respect to lethal temperatures and critical thermal limits） and a compromised temperature tolerance of parasitoid C. sesamiae relative to its host, suggesting potential asynchrony between host-parasitoid population phenology and con- sequently biocontrol efficacy under global change. These results have broad implications to biological pest management insect-natural enemy interactions under rapidly changing thermal environments.