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The thermochromic properties of two donor–acceptor type fluorescent molecules DpAn-InAc and DpAn-BzAc in powder- and film-states were studied.

A novel solvatochromic fluorescent molecule, i.e., DpAn–InAc, is reported and synthesized using a palladium-catalyzed Buchwald–Hartwig cross-coupling process. DpAn–InAc exhibits thermally activated delayed fluorescence character. It has a twisting donor–acceptor configuration, which contributes to interesting solvatochromic properties when changing the excitation energy and the orientational polarizability of the solvent. Fluorescent solvatochromic experiments for DpAn–InAc solutions show a red shift of 90 nm from 540 nm in toluene to 630 nm in tetrahydrofuran. The photoluminescence spectrum of DpAn–InAc in chloroform solution of medium polarity shows dual emission peaks at 450 nm and 550 nm, originating from low-lying local excited (LE) and charge-transfer (CT) states, respectively. When decreasing the excitation energy gradually, it is found that the main excited state of DpAn–InAc changes from the CT state to the LE state. DpAn–InAc has great potential in applications including fluorescent probes and fluorescent sensors.

Using a laser to heat microfluid has the advantages of non-contact local operation, high accuracy, and good adjustability. In this study, a focused infrared laser with a 1550-nm wavelength was applied to heat an oil–water-oil double-emulsion droplet in a microchannel. The Finite Volume Method was used to numerically study the thermocapillary flow and heat transfer of this laser-heating process. In the simulation, the laser energy distribution was modeled using a volumetric Gaussian heat source. The attention was focused on the heat transfer and thermocapillary flow of the double-emulsion droplet. The influences of laser parameters (power and beam diameter) and the temperature coefficient of interfacial tension were studied. We found that the intensity of the thermocapillary flow and the temperature linearly increased with input power; they first decreased and then increased as the size of the input beam increased because of the combined effect of absorbing energy and energy concentration. Moreover, there were four and two thermocapillary vortices inside the middle water phase when the sign of the temperature coefficient of interfacial tension in the double interfaces was the same and different, respectively. In all cases, the uneven temperature coefficient of the inner droplet was lower than that of the middle water phase, but the average temperatures of both regions were extremely close. These results can prove useful in the future operation of double-emulsion droplet-based microfluidics using a laser as a precise and sensitive heating source for drug discovery and delivery, cell analyses, and micro/nanoparticle synthesis.

Localized fluid manipulation in microfluidic device is a key operation to various on-chip analytical/synthetic applications. In this work, we demonstrated the localized fluid actuation in microchannels by the infrared laser-induced evaporation–condensation-coalescence photothermal phase change process. Visualized experiments were carried out to investigate the dynamic phase change process and accompanying interfacial behaviors. Effects of laser power, spot speed, channel structure and actuation distance were investigated. Results indicate the actuation speed can be tuned by the output laser power, and the flow direction in microchannels can be selected by the control of laser spot trajectory. Long distance actuation performance suggests that the flow speed decreases due to the increase of fluid volume and flow resistance. The photothermally induced phase change process provides the means of simple and efficient localized fluid manipulation with remarkable dynamic response and the ability of agile maneuver in microfluidic channels, which could be further applied in different application scenarios.

The coalescence between the advancing liquid meniscus and multiple droplets is usually encountered in the liquid filling process and photothermal effect based microdevices. To shed light on how the coalescence between the advancing liquid meniscus and multiple droplets affects the liquid meniscus advancement, its dynamic behaviors are numerically investigated using the coupled level set and volume-of-fluid (CLSVOF) method along with the continuum surface force (CSF) model in this study. Particular attention is paid to the dynamic interfacial phenomena during the coalescence process. The effect of the droplet and its volume distributions is also investigated. The simulation results show that the coalescence between the advancing liquid meniscus and each droplet is able to instantly accelerate the original liquid flow as a result of the induced concave meniscus with large curvature. As compared to the coalescence with a single droplet, the fluctuation and deformation of the interface is stronger in the case of simultaneous coalescence with multiple droplets, which can further lower the average liquid pressure and thus show more significant advancement of the liquid flow. The velocity increment ratio is the largest when four droplets simultaneously coalesce with the advancing liquid meniscus. It is shown that the coalescence with large droplet can result in large velocity increment ratio because more surface energy is supplied. Large length of the advancing liquid segment before its coalescence with the droplets can weaken the advancing effect. It is also found that the overall variation trend of the simulation results is in agreement with that of the experimental results.

We have investigated the failure mechanism of organic functional materials and organic light-emitting diodes (OLEDs) by annealing at high temperatures. We found that N,N'-bis(naphthalen-1-yl)-N,N'-bis(phenyl)-benzidine (NPB) doped molybdenum oxide and 1,3,5-tri[(3-pyridyl)-phen-3-yl]benzene doped cesium carbonate can enhance the thermal stability significantly. The former composite film reveals the ions of NPB, as observed by X-ray photoelectron spectroscopy (XPS), the formation of which shows that NPB receives the electron that Mo loses. Meanwhile, it is stable for the binding energy of the element in the latter composite film from the XPS image. Through the research of carrier-only cells, the observation indicates that the thermal stability of the doped cell is better than that of the undoped cell at high temperatures. The current efficiency of the doped device is only reduced by 12% after annealing at 80℃; meanwhile the lifetime reaching 208 h is the longest among that of the devices. Simultaneously, the undoped device represents a larger decline even of about 30% with the lifetime reaching just 40 h. We assumed that the enhanced heat-resisting properties of organic materials by inorganic doping might be attributed to the decrease of energy barrier and the reduction of the interface charge accumulation phenomenon caused by high temperature. Inorganic doping paves an alternative way to substitute for synthesizing expensive functional materials with high glass transition temperature.

The development of highly efficient photocatalytic reactor is of importance to improve the performance of the photocatalytic reduction of CO2. In this work, an optofluidic planar microreactor is designed and fabricated for the photocatalytic reduction of CO2 with liquid water in alkaline environment. Such design offers several advantages of large surface-area-to-volume ratio, enhanced mass and photon transfer and more uniform light distribution. The performance of the developed planar microreactor is evaluated by measuring the methanol concentration to estimate the methanol yield under various operating parameters, including the liquid flow rate, light intensity, catalyst loading and NaOH concentration. It is shown that increasing the liquid flow rate firstly improves and then decreases the methanol concentration while the methanol yield continuously increases as the liquid flow rate increases. The increase of the light intensity and NaOH concentration increases both the methanol concentration and yield. Increasing the catalyst loading firstly improves the performance and then results in the reduction of the performance. A maximum methanol yield of 454.6 μmole/g-cat·h is achieved under a liquid flow rate of 50 μL/min, 0.2 M NaOH, and the light intensity of 8 mW/cm2.

Smoothed particle hydrodynamics (SPH), is a meshfree, Lagrangian, particle method, which is advantageous over conventional grid-based numerical methods in the aspect of interface treatment. Therefore, it has shown promising potential for simulating the multiphase flow problems. Over the past decades, numerous efforts have been devoted to the simulation of the multiphase flow by using the SPH method. In this review, recent advances in SPH for simulating the multiphase flow are reviewed. Firstly, the basic concept of SPH is briefly introduced. Attention is then paid to how to treat the pressure of incompressible flow, boundary condition and the surface tension in SPH. In addition, modeling free surface flow is briefly introduced. The modified interfacial models and their applications in handling high density ratio are addressed. Finally, a summary of SPH in the application of the multiphase flow is given.

Objective: To evaluate the accuracy of noninvasive glucometer based on metabolic heat conformation (MHC) method by multicenter clinical trial. Methods: This study was a multi-center, open, self-controlled trial. Venous plasma glucose measured by the hexokinase method was taken as reference level. The screening period was 1 to 7 days before the test, and a fasting blood glucose of the subjects who enrolled to this study was recorded as a calibration value. Subjects were tested at 3 time points successively on experimental day: fasting, 2-hour and 4-hour postprandial. On each time point, the noninvasive glucose measurement was performed at first, and followed by venous blood sample collection within 5 minutes. The subjects ate the 80 g standard noodle meal after the fasting test. The meal should be finished within 15 minutes. Results: 3 centers participated with 210 subjects (M/F=98/112, average age is 61.2 year-old, 200 with T2DM, 7 with T1DM, 3 with prediabetes) were enrolled. The correlation coefficient of noninvasive glucose value and the serum glucose value in fasting, 2h and 4h postprandial status was 0.79, 0.61, 0.63 respectively. Conclusion: The noninvasive glucometer based on MHC method showed a good correlation with the venous plasma glucose, especially in fasting state. Disclosure A. Li: None. Z. Geng: None. S. Li: None. X. Guo: None. J. Zhang: None. F. Tang: None.

In this study, the photothermal effect of an infrared laser induced evaporation and Marangoni convection of a liquid column in microchannels is numerically studied. The volumetric Gaussian heat source is used to model the laser beam and the shear stress at the vapor–liquid interface due to the surface tension gradient is accounted. The results show that under the same laser spot position and laser power, the evaporation mass flow rate in the hydrophilic microchannel is greater than that in the hydrophobic microchannel due to the small thermal resistance. The direction of flow patterns in liquid column are totally different since the relative magnitudes of the horizontal and vertical temperature gradients are opposite for these two surfaces. The effects of the laser power and spot position are also studied. It is found that as the laser power increases, the evaporation mass flow rate, evaporation heat ratio and strength of the Marangoni convection are all increased because more heat can be generated. Regarding the laser spot position, the evaporation mass flow rate and evaporation heat ratio both decrease with increasing the distance between the laser spot and interface because of increased thermal resistance. Moreover, the laser spot position can change the Marangoni convection roll both by the direction and magnitude. The results obtained are helpful for the design and operation of the microdevices with the photothermal effect induced phase change.

The photothermal effect induced phase change is an important phenomenon in optofluidics. In this work, therefore, the characteristics of the phase change in microchannels with different depths induced by a 1550 nm infrared laser under both low and high laser powers was visually studied. It was revealed that at low laser power, the liquid body could be always advanced as a result of the induced evaporation–condensation–coalescence process regardless of the microchannel depth, which can function as a micro pump. The μ-PIV testing results further demonstrated the coalescence was a dominant mechanism in the interface advancement. Interestingly, although large depth increased the absorption length of the laser and thus improved the temperature and enhanced the evaporation, the advancing effect became weak due to the increase of both the flow resistance and liquid water content to be driven. At high laser power, for small depth microchannel, the liquid body was advanced at the beginning. Once a liquid slug alon...

Photocatalytic reduction of CO 2 is a promising technology to capture CO 2 and convert it into solar fuels simultaneously. However, current photoreactors usually face the problems of low specific surface area, non-uniform light distribution and poor photon transfer. To address these issues, a novel optofluidic membrane microreactor with high surface-area-to-volume ratio, enhanced photon and mass transport and uniform light distribution was proposed in this work by combining optofluidics with the membrane reactor technology for the photocatalytic reduction of CO 2 with liquid water. A TiO 2 /carbon paper composite membrane was prepared as the photocatalytic membrane via coating TiO 2 onto the carbon paper followed by hydrophobic treatment by poly-tetrafluoroethylene (PTFE) for the separation of the gas/liquid phases. The performance of the proposed optofluidic membrane microreactor was evaluated by measuring the methanol yield. The effects of the liquid water flow rate, light intensity and catalyst loading on the methanol yield were also studied. It was shown that a maximum methanol yield of 111.0 μmole/g-cat·h was achieved at a flow rate of 25 μL/min and under the light intensity of 8 mW/cm 2 , which is among the top in comparison to the reported data. Results obtained fully demonstrate the feasibility and superiority of the proposed optofluidic membrane microreactor for the photocatalytic reduction of CO 2 .

The dynamic behavior of the moving liquid column coalescing with a sessile droplet in triangular microchannels is numerically investigated by using coupled volume of fluid with level set interface tracking method implemented in ANSYS Fluent 14.5 in conjunction with the continuum surface force model. It is found that for both hydrophobic and hydrophilic microchannels, the coalescence between the moving liquid column and droplet can accelerate the original liquid column movement as a result of the induced curvature that lowers the liquid pressure at the interface. As compared to the rectangular microchannel with the same hydraulic diameter, the triangular microchannel exhibits smaller velocity increment ratio because of stronger viscous effect. Simulation results also reveal that the velocity increment ratio increases with the contact angle in hydrophobic microchannels, but it is reverse in the hydrophilic microchannels. The effects of the droplet size, lengthways and transverse positions are also investigated in this work. It is shown that larger droplet and smaller distance between the droplet and inlet or the substrate center can result in larger velocity increment ratio as a result of higher surface energy and lower viscous dissipation energy, respectively. The results obtained in this study create a solid theoretical foundation for designing and optimizing microfluidic devices encountering such a typical phenomenon.

Microfluidic devices for sample crystallization separation plays crucially important role in various on-chip analytical and testing scenes. Evaporation-based microfluidic crystallization technology is one of the most important methods for on-chip sample enrichment and crystallization separation. However, the solvent evaporation process in closed chip device is severely limited by poor vapor transportation, unstable interfacial behaviors and low evaporation rate. Aiming to address these issues, here we designed a microfluidic membrane evaporator for fast continuous flow sample crystallization separation. In this design, laser induced heating effect was employed to trigger the evaporation of the solvent, gas-permeable hydrophobic polytetrafluoroethylene membrane was used to stabilize the gas-liquid interface and provide vapor pathways during the evaporation process. Effects of laser power, solution flow rate and sample concentration on the crystallization separation performance was investigated. Results indicates the designed microfluidic membrane evaporator has good crystallization separation performance under different operation conditions, which can be further applied to different types of microfluidic systems and platforms for on-chip analysis and testing.

Blood flow volume, an important parameter of microcirculation, has been measured in many studies. In this study, an easy-to-use heat transfer method is developed to measure the blood flow volume of peripheral tissues in humans. This method is based on a one-dimensional biological heat transfer and three-dimensional conductor heat transfer model, which requires temperature measurements at the skin and two ends of the conductor. A mathematical simulation is established to guide the actual signal processing method. The results demonstrate that the heat transfer method is feasible for measuring the blood flow volume in peripheral tissues such as the fingertip. Moreover, a sensor system is developed to carry out experiments using human fingers. The results correlate well with data from a laser Doppler device, with a correlation coefficient of 0.89. The proposed heat transfer method can be used to accurately measure blood flow volume.

The coalescence between liquid flow and droplets is usually encountered in liquid filling or some new microdevices; a deep understanding of its underlying mechanism is required. In this work, therefore, the dynamic behaviors of this atypical phenomenon in microchannels were visually investigated with droplets generated by photothermally induced evaporation and condensation. The effects of droplet quantity and position, inlet pressure, and microchannel size were also explored. Experimental results showed that the coalescence accelerated the liquid movement as a result of lowered pressure at the interface. Parametric studies indicated that large droplet quantity and small distance between the inlet and droplets yielded a large velocity increment ratio as a consequence of lowered liquid pressure at the interface and increased pressure gradient, respectively. A high peak velocity increment but with low velocity increment ratio was obtained at high inlet pressure because of high liquid flow velocity. Moreover,...

In this work, the condensation behaviors of distilled water actuated by photothermal effect of the infrared laser with the wavelength of 1550 nm in a microchannel were investigated through the visualization method and image processing technique. The impacts of the laser power and the laser spot position on the interface movement and slug formation were also explored. It is found that the interface tended to be advanced as a result of the photothermally induced evaporation–condensation–coalescence process at lower laser powers while the interface was firstly advanced at the beginning and then moved backward after the liquid slug formation in front of the interface at high laser powers. Experimental results also showed that higher laser power and smaller distance between the initial gas–liquid interface and fixed laser spot yielded faster advancing of the gas–liquid interface. For cases with the liquid slug formation, the growth rate of the liquid slug increased with increasing the laser power and decreasing the distance of the laser spot position away from the initial interface position as a result of a high evaporation rate.

Daily continuous glucose monitoring is very helpful in the control of glucose levels for people with diabetes and impaired glucose tolerance. In this study, a multisensor-based, noninvasive continuous glucometer was developed, which can continuously estimate glucose levels via monitoring of physiological parameter changes such as impedance spectroscopy at low and high frequency, optical properties, temperature and humidity. Thirty-three experiments were conducted for six healthy volunteers and three volunteers with diabetes. Results showed that the average correlation coefficient between the estimated glucose profiles and reference glucose profiles reached 0.8314, with a normalized root mean squared error (NRMSE) of 14.6064. The peak time of postprandial glucose was extracted from the glucose profile, and its estimated value had a correlation coefficient of 0.9449 with the reference value, wherein the root mean square error (RMSE) was 6.8958 min. Using Clarke error grid (CEG) analysis, 100% of the estimated glucose values fell in the clinically acceptable zones A and B, and 92.86% fell in zone A. The application of a multisensor-based, noninvasive continuous glucometer and time series analysis can endure the time delay between human physiological parameters and glucose level changes, so as to potentially accomplish noninvasive daily continuous glucose monitoring.

The dynamic behavior of the moving liquid column coalescing with a sessile droplet in a hydrophilic microchannel is simulated in this work using the volume of fluid (VOF) methodology along with the continuum surface force (CSF) model. Particular attention is paid to the dynamic interfacial phenomena during the coalescence and the effect on advancing the water–air interface. It is interesting to find that the coalescence between the moving liquid column and droplet can accelerate the original liquid column movement due to the formation of the lager-curvature meniscus at the interface induced by the coalescence, which increases the capillary pressure. In addition, effects of the wettability, the sizes of the microchannel and droplet as well as the droplet position on the coalescence behaviors and liquid column movement are also studied. The results show that more hydrophilic surface, smaller channel size and distance between the droplet and inlet, and larger droplet size exhibit a larger acceleration rate as a result of induced higher capillary pressure.

To facilitate the manufacturing of a ball-end mill, this paper presents an algorithm for ball-end mills gashing by using a five-axis computer numerical control (CNC) grinding machine. In this study, the normal helix models are proposed. Then, based on the cutting edge geometric model and the machining mode of the five-axis computer numerical control (CNC) grinding machine, the coordinate of the grinding point when the step of the gash out is grinded will be calculated. With the input data of ball-end mill geometry, wheels geometry, wheel setting and machine setting, the NC code for machining will be generated. Then the code will be used to simulate the ball-end mill machining in 3 Dimension. The 3D simulation system of the ball-end mill grinding is generated by VBA and AutoCAD2008. The algorithm of ball- end mill gashing can be verified by the 3D simulation system. Result shows that the algorithm presented in this paper provides a practical and efficient method for the manufacture of a ball-end mill gashing.

With the recent realization of hybrid improper ferroelectricity and room-temperature multiferroic by tilt engineering, “functional” octahedral tilting has become a novel concept in multifunctional perovskite oxides, showing great potential for property manipulation and device design. However, the control of magnetism by octahedral tilting has remained a challenging issue. Here a qualitative and quantitative tilt engineering of exchange coupling, one of the magnetic properties, is demonstrated at compensated G-type antiferromagnetic/ferromagnetic (SrMnO3/La2/3Sr1/3MnO3) interfaces. According to interfacial Hamiltonian, exchange bias (EB) in this system originates from an in-plane antiphase rotation (a−) in G-type antiferromagnetic layer. Based on first-principles calculation, tilt patterns in SrMnO3 are artificially designed in experiment with different epitaxial strain and a much stronger EB is attained in the tensile heterostructure than the compressive counterpart. By controlling the magnitude of octahedral tilting, the manipulation of exchange coupling is even performed in a quantitative manner, as expected in the theoretical estimation. This work realized the combination of tilt engineering and exchange coupling, which might be significant for the development of multifunctional materials and antiferromagnetic spintronics.

The intelligent power community as an important part of smart grid electricity sectors, to achieve real-time interaction between the grid and the user response, enhance grid integrated service capabilities to meet the needs of an important means of interactive marketing. Intelligent power cell and focuses on the smart power technology advanced, cost-effective, flexible interaction and other features. Papers discussing smart grids, intelligent power cell, based on the intelligent power residential construction were studied.

In this paper, with advanced computer technology and distribution network planning theory, studied with GIS-based distribution network planning aided design system. This paper analyzes the problems of distribution network planning, proposed the use of FME technology planning data integration and appreciation of thinking, to achieve a reasonable distribution network planning related GIS data and graphics data; secondly distribution network planning based on actual work demands, flexible data modeling methods to achieve the efficient management of data distribution network planning; Finally, according to the dynamic nature of the distribution network planning, multi-objective, non-linear, discrete, indeterminate features, the establishment of a spatial load analysis model and distribution network optimization model, and uses GIS path search algorithm auxiliary design features. The system for the power companies to achieve data integration planning and implementation of distribution network planning aided design has certain significance.

It is the direction of the global power industry that market-oriented reform of the power industry. Although the ways in which States electricity reform, basic, pattern design vary, but the goal of power industry reform are the same, is to break the monopoly and introducing competition mechanism, improve efficiency, reduce social costs (including electricity costs, resource costs, environmental costs, etc.).Combined with the actual situation of the domestic power sector reforms, the process of reform and development of China's power market rules of electricity are discussed and research.

Sunlight is constantly changing during the year, including a certain regularity random variation due to weather changes and the result. Thus, by the light on the photovoltaic power generation system is also in flux. Incorporated into the distribution network after PV, the network will change the trend, causing node voltage changes, and the impact on the voltage regulator. With the development of photovoltaic technology and grid technology, more and more incorporated into photovoltaic power distribution network, to the distribution network of operational control brings various effects. This paper analyzes the impact of PV grid distribution network voltage regulation, and summed up the resolve PV grid distribution network Voltage on approach.