Study on a Noncontact Microdroplet Separation Method under the Action of Corona Discharge.

Precision manipulation of various liquids is essential in many fields such as various thermal, optical, and medical applications. This paper proposes an effective noncontact microdroplet separation method that is based on the action of corona discharge. A blade-plate electrode is constructed to generate an ionic wind, thereby enabling the droplet to be separated according to the shape of the blade electrode. Line, curve, S-shape, and parallel separation of the droplet can be realized in the experiment setup. Furthermore, experiment parameters, including the driving voltage, cutting speed, the distance of the upper and lower electrodes, cutting depth, etc., are discussed. Experimental results show that the proposed method is feasible and effective and can be used in application scenarios that require precise manipulation of droplets.

Study on the Formation and Controllable Movement of Polymer Liquid Columns Based on Dynamic Control of Spatial Electric Field Distribution.

Liquid deformation and motion are very common natural phenomena and of great value in various practical applications. In this study, a dielectric fluid column formation and directional flow phenomenon are presented. Dielectric fluid can grow upward to form a liquid column through a spatial electric field and realize directional and controllable operation of the liquid column by regulating spatial electric field distribution. First, the adjustable electric field space is constructed by connecting the two parallel electrodes to the high-voltage DC power supply. Then, the regional electric field distribution was adjusted by the upper plate graphic and power supply regulation to drive the polymer liquid on the lower plate electrode to form a liquid column at different positions. The results show that the polymer liquid column can be driven by the spatial electric field distributed dynamic control method and that the height and the narrowest width of the liquid column are directly controlled by the voltage. With the experiment conditions that the distance between two parallel electrodes is 5-15 mm, the formation of liquid columns with a height of 5-15 mm can be controlled. In addition, the liquid column can be driven by adjusting the on-states of different conductive regions. When the voltage is 10 kV, the liquid column directional movement speed can reach 1 mm/s. The higher the voltage, the faster the directional movement. The research results can be used as producing polydimethylsiloxane stamp, localized heating and temperature control, fabricating a pulsating heat pipe, and so on.

Three-Dimensional Droplet Manipulation with Electrostatic Levitation.

An active and precise method for three-dimensional (3D) droplet manipulation is introduced. By modulating the local electrostatic force acting on droplets in carrier oil between needle plate electrodes, the vertical motion of droplets can be controlled, including the droplet levitation at the interface between the carrier oil and the air. Levitated droplets can be translated horizontally with high efficiency by the motion of the needle electrode. With controllable local deformation on the flexible plate electrode, selective manipulation can be realized for multiple droplets. Applying the manipulation method proposed, a platform is built and various droplet handling, such as transport, merging, and mixing, is performed effectively. Complex droplet transport trajectories are achieved by moving the needle electrode. The droplet transport velocity can reach up to 37 mm/s. The introduced method has fundamental advantages of avoiding cross-contamination between droplets, enhancing the flexibility, eliminating the transport track constraint, and lowering costs with straightforward and precise droplet manipulation.

Controllable Flowing of a Dielectric Fluid Droplet under the Action of Corona Discharge.

Polymer microfluidic technology is widely used in chemistry, biology, medicine, nanoparticles synthesis, and other fields. In this article, we introduce a novel method for the controllable flowing of dielectric fluid droplets. Under the action of corona discharge, the dielectric fluid droplet can be controllably driven to one or more conductive plate electrodes that are connected to the negative electrode on the substrate. Phenomena of polymerization, migration, and separation and merger are experimentally verified in detail, and the spreading speeds and steady-state time are discussed. The experimental results show that the proposed method is accurate and controllable.

Boosting Electrically Actuated Manipulation of Water Droplets on Lubricated Surfaces through a Corona Discharge.

Controllable liquid transportation is of great value in various practical applications. Here, we experimentally demonstrate a method of actuating high-speed droplet transport with large manipulation controllability on lubricated surfaces using a corona discharge generated by a simple needle-plate electrode configuration. Linear motion of droplets is realized with a maximum velocity of 30 mm/s. Factors affecting the velocity of these droplets are analyzed systematically, and the mechanism of droplet transport is explained. The lubrication film flow induced by charge deposition is shown to be the dominating factor in the droplet manipulation controllability. The new method presented here opens a new path of high-performance manipulation of liquid droplets by controlling the lubrication liquid film flow with charge deposition.

Contactless Discharge-Driven Droplet Motion on a Nonslippery Polymer Surface.

Droplet manipulation is the cornerstone of many modern technologies. It is still challenging to drive the droplet motion on nonslippery surfaces flexibly. We present a droplet manipulation method on nonslippery polymer surfaces based on the corona discharge. With the corona discharge of two-needle electrodes with opposite polarities, the droplet's charge polarity can be switched, which results in the directionally droplet transport on a charged polymer surface with the oscillation. Here, such droplet behaviors are presented in detail. Dependence of the motion on the critical distance and driving distance between the droplet and the needle electrode is revealed. The driving mechanism is verified by experiments and simulations. This work enriches the droplet manipulation techniques on nonslippery surfaces for various applications, such as combinatory chemistry, biochemical, and medical detection.

[Pharmacokinetics of eight active ingredients of Salviae Miltiorrhizae Radix et Rhizoma-Puerariae Lobatae Radix combination in rats].

To reveal the rationality of compatibility of Salviae Miltiorrhizae Radix et Rhizoma(SMRR) and Puerariae Lobatae Radix(PLR) from the perspective of pharmacokinetics, this study established a UPLC-MS/MS method for quantitative determination of PLR flavonoids(3'-hydroxy puerarin, puerarin, puerarin 6″-O-xyloside, 3'-methoxy puerarin, puerarin apioside) and salvianolic acids and tanshinones(salvianolic acid B, cryptotanshinone, and tanshinone Ⅱ_A) in plasma of rats. Rats were given SMRR extract, PLR extract, and SMRR-PLR extract by gavage and then plasma was collected at different time. UPLC separation was performed under the following conditions: Eclipse C_(18) column(2.1 mm×50 mm, 1.8 µm), 0.1% formic acid in water(A)-0.1% formic acid in acetonitrile(B) as mobile phase for gradient elution. Conditions for MS are as below: multiple reaction monitoring(MRM), ESI~(+/-). Comprehensive validation of the UPLC-MS/MS method(specifically, from the aspects of calibration curve, precision, accuracy, repeatability, stability, matrix effect, extract recovery) was performed and the result demonstrated that it complied with quantitative analysis requirements for biological samples. Compared with SMRR extract alone or PLR extract alone, SMRR-PLR extract significantly increased the AUC and C_(max) of PLR flavonoids and tanshinones in rat plasma, suggesting that the combination of SMRR and PLR promoted the absorption of the above components. The underlying mechanism needs to be further studied.

Enhancing the thermal dissipation of a light-converting composite for quantum dot-based white light-emitting diodes through electrospinning nanofibers.

Quantum dots (QDs) have been developed as one of the most promising light-converting materials for white light-emitting diodes (LEDs). In current QD-based LED packaging structures, composites of QDs and polymers are used as light-converting layers. However, the ultralow thermal conductivity of such composites seriously hinders the dissipation of QD-generating heat. In this paper, we demonstrate a method to enhance the thermal dissipation of QD-polymer composites through electrospinning polymer nanofibers. QD-polymer films embedded by electrospun nanofibers were prepared. Benefitting from aligned polymer chains in the electrospun nanofibers, the through-panel and in-panel thermal conductivities of the proposed QD-polymer film increased by 39.9% and 423.1%, respectively, compared to traditional QD-polymer film. The proposed and traditional QD-polymer films were both packaged on chip on board (CoB) LEDs for experimental comparison. Compared to traditional QD-polymer film, the luminous flux and luminous efficiency of the LEDs were increased by up to 51.8% and 42.9% by the proposed QD-polymer film under a current of 800 mA, respectively. With an increase in the driving current from 20-800 mA, the correlated color temperature (CCT) variation decreased by 72.7%. The maximum temperatures in the QD-polymer films were reduced from 419 K-411 K under a driving current of 200 mA.

Optical performance enhancement of chip-on-board light-emitting diodes through ionic wind patterning.

Due to the total internal reflection at the upper interface of the encapsulation layer, the light extraction efficiency (LEE) of chip-on-board packaging light-emitting diodes is attenuated significantly. It is well known that the LEE can be enhanced by patterning the encapsulation layer. In this study, a novel method of patterning the encapsulation layer, which is based on the interaction between the ionic wind and liquid encapsulation, is proposed and demonstrated. Two kinds of encapsulation patterns, namely dual stripe and meniscus, were fabricated successfully. Compared with the traditional flat encapsulation structure, dual stripe and meniscus patterns enhanced the LEE by 17.78% and 20.48%, respectively. Meanwhile, light intensity distributions were observed to be more uniform. The proposed encapsulation patterning method demonstrates significantly simplified fabrication process and reduced cost.

Optical performance improvement of phosphor-in-glass based white light-emitting diodes through optimized packaging structure.

To improve the optical performance of multi-component phosphor-in-glass (PiG) based white light-emitting diodes (WLEDs), we proposed an optimized packaging structure, which is a combined structure of a patterned PiG with a crater-type lens. The patterned PiG yields a red phosphor circle surrounded by a yellow phosphor concentric ring. Comparison simulations and experiments between the conventional mixed structure, patterned structure, and proposed structure were conducted. Compared with the mixed structure and patterned structure, the luminous efficacy of the proposed structure is increased by 19.3% and 10.7% at the driving current of 350 mA, respectively. Furthermore, the deviation of the correlated color temperature (CCT) of the patterned PiG is reduced from 906 to 129 K by the crater-type lens at the average CCT of 4100 K. The results demonstrate that the proposed packaging structure can improve the luminous efficacy and angular color uniformity (ACU) of a PiG-based WLED simultaneously.

[Study on the Catalytic Kinetic Spectrophotometric Determination of Trace Amounts of Iron(â ¢) and Its Reaction Mechanism].

A catalytic kinetic spectrophotometric method, which is based on the catalytic effect of Fe(Ⅲ) on the fading reaction between potassium persulfate(K2S2O8) and methyl red(MR) in the solution of 0.30 mol·L-1 hydrochloric acid, for the determination of trace amounts of Fe(Ⅲ) has been investigated. A novel detection system, Fe(Ⅲ)-HCl-K2S2O8-MR, has been developed. The optimum experimental conditions for the determination of trace amounts of Fe(Ⅲ) were found on the basis of orthogonal test. The kinetics parameters and equation of this fading reaction of MR were studied. Its reaction mechanism was discussed. The results show that there is a good linear relationship between the variation of MR absorbance at the maximum absorption wavelength of 518 nm and the concentration of Fe(Ⅲ) under the optimum experimental conditions: ln(A0/A)=1.334 1+0.001 0, the correlation coefficient is 0.999 1. The kinetic research shows that the reaction order with respect to Fe(Ⅲ) is 1 and the overall fading reaction is a pseudo-first order reaction. The apparent activation energy of the fading reaction of MR is 69.88 kJ·mol-1. Furthermore, the catalytic effects of Fe(Ⅲ) on this fading reaction is confirmed by its reaction mechanism. This novel method for the determination of trace Fe(Ⅲ) has never previously been published so far. Trace amounts of Fe(Ⅲ) can be selectively determined by this catalytic kinetic spectrophotometric method with high precision and accuracy. This method is simple and its reagents used are cheap and available. Its sensitivity is higher than that of conventional spectrophtometry with detection limit of 0.005 mg·L-1. This detection system is stable. This proposed method has been applied to the determination of trace amounts of Fe(Ⅲ) in food and water samples with satisfactory results. Relative standard deviation of the detection results is 1.18%～2.11%. Average recovery rate of the detection results is 98.0%～104.0%.

[Study on the Preparation of A New Composite Coagulant: Poly-Ferric-Titanium-Sulfate and Analysis of FTIR Spectrum and UV-Vis Spectrum].

Composite coagulants have drawn a widespread attention recently for its superior coagulation-flocculation performance. Fe and Ti based coagulants, as a kind of inorganic metal water treatment agent, h have received huge attention, but there is little study about the preparation and characterization of composite coagulate composite with Ti4+. In this paper we prepared a composite coagulant, in which the Ti (SO4)2 was introduced as coordination complexes, PO3-4 as stabilizer and complexant. Then, the FT-Infra Red spectrum (FT-IR) and ultraviolet/visible absorption spectrum (UV-Vis) were adopted to characterizse the changes of chemical group, species distribution of coagulants in case of varies Ti/Fe, P/Fe and OH/Fe molar ratio. The results shows other than simple mixture of the raw materials, the introduction of Ti4+ and ­PO4 group synthesized the chemical group bond as Ti­O, ­Fe­P­Fe­ and ­Ti­P­Ti­, which were beneficial to the degree of polymerization and increased the stability of the product. Furthermore, when the Ti/Fe molar ratio of 1∶8, P/Fe was in the range of 0.2~0.3, the optimal material is suitable for the generation of Fe­P­Ti­ chemistry bond and medium polymer as Fe6(OH)6+12，[Fex(OH)y]2H2PO(6x-2y-1)+4. Whereas, too much addition of Ti4+, PO3-4 and HCO-3 deteriorated the polymer structure, leading to the presentation of precipitate as TiO2, Ti3(PO4)4 and FePO4, which will decrease the coagulation performance.

[The Preparation and Characterization of a New Solid Coagulant: Polymeric Ferric Silicate Sulfate].

As one of the most important water treatment agents, polysilicate coagulant, has been playing an important role in coagulation- flocculation, but it is prone to lose stability due to self-polymerization and the forming of silica gel. Therefore, research on the preparation of stable polysilicate coagulant has attract great attention. A new method to prepare a stable polysilicate coagulant (PSPF), was proposed in this paper. Its structure and morphology were characterized by using Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) respectively. Fe species in PSPF was analyzed via Fe-Ferron complexation timed spectrophotometric method. The performance of PSPF was assessed by measuring micro-polluted water treatment efficiency. Primary chemicals, such as ferrous sulfate, sodium silicate, potassium dihydrogen phosphate, sodium carbonate, were used. The influence of those parameters affecting the preparation of PSPF, such as nSi/nFe, nP/nFe and nOH/nFe molar ratios were examined. The results showed that nSi/nFe of 1∶4, nP/nFe of 1∶6 and nOH/nFe of 1∶10 under 60 ℃ water bath for 30 min was the optimum condition for preparation. The FTIR spectrum indicated that PSPF was a kind of high molecular polymer, containing new groups (e.g., Si­O­Si and Fe­O­Si), which could increase the molecular weight，molecular chain and coagulation-flocculation efficiency. PSPF presented a cluster appearance similar to a network structure, which was conductive to adsorption-bridging capacity and precipitation sweeping. The increase of Fe(b) and Fe(c) as a result of Si increasing in PSPF improved the polymerization and solidification. The coagulation behaviors of PSPF that were largely affected by the coagulant dosage and pH, indicated that for pH and dosage at 6 and 8 mg·L-1, respectively, the residual turbidity and UV254 removal efficiency could achieve 0.33 NTU and 58.6%, respectively.

[Study on the Influence of Mineralizer on the Preparation of Calcium Aluminates Based on Infrared Spectroscopy].

In this study, effect of mineralizer on the structure and spectraproperties of calcium aluminates formation was extensively studied. Medium or low-grade bauxite and calcium carbonate were used as raw material and mineralizer CaF2 as additive. Calcium aluminates can be obtained after mixing fully, calcination and grinding. The prepared calcium aluminates can be directly used for the production of polyaluminiumchloride (PAC), polymeric aluminum sulfate, sodium aluminate and some other water treatment agents. The calcium aluminates preparation technology was optimized by investigating the mass ratio of raw materials (bauxiteand calcium carbonate) and mineralizer CaF2 dosage. The structure and spectra properties of bauxite and calcium aluminates were characterized by Fourier transform infrared(FTIR) spectroscopy analysis and the mineralization mechanism of the mineralizer was studied. FTIR spectra indicated that the addition of mineralizer promoted the decomposition and transformation of the diaspore, gibbsite and kaolinite, the decomposition of calcium carbonate, and more adequately reaction between bauxite and calcium carbonate. In addition, not only Ca in calcium carbonate and Si in bauxite were more readily reacted, but also Si-O, Si-O-Al and Al-Si bonds in the bauxite were more fractured which contributed to the release of Al in bauxite, and therefore, the dissolution rate of Al2O3 could be improved. The dissolution rate of Al2O3 can be promoted effectively when the mineralizer CaF2 was added in a mass ratio amount of 3%. And the mineralizer CaF2 cannot be fully functioned, when its dosage was in a mass percent of 1. 5%. Low-grade bauxite was easier to sinter for the preparation of calcium aluminates comparing with the highgrade one. The optimum material ratio for the preparation of calcium aluminates calcium at 1 250 °C was the mass ratio between bauxite and calcium carbonate of 1 : 0. 6 and mineralizer CaF2 mass ratio percent of 3%.

Cloning and respond of a cold shock domain protein (CnCSDP) gene to cold stress in noble scallop Chlamys nobilis (Bivalve: Pectinidae).

Cold shock domain proteins (CSDPs) play various roles in cellular processes, including adaptation to low temperature in mollusk. In this study, the cDNA encoding CSDP in noble scallop Chlamys nobilis was cloned (CnCSDP), and its transcript profile in cold-stressed orange and brown strains was analyzed using real-time RT-PCR. Bioinformatic analysis shows that the complete CnCSDP cDNA is 1,434 bp in length, consisting of a 5'-, and 3'-untranslated region of 86 and 466 bp, respectively, and a 882 bp open reading frame encoding 294 amino acids with an estimated molecular mass of 33.23 kDa and an isoelectric point of 9.72. Furthermore, CnCSDP has two consensus RNA binding domains, four DNA binding sites and four RGG repeats. CnCSDP transcripts amount in the blood of orange strain were significantly higher, while in the mantle were much lower than that of brown strain. In the cold-stressed orange strain, CnCSDP mRNA decreased dramatically in the blood and mantle, but was significantly up-regulated at 1 h, and progressively returned to its original levels in the gill. In the cold-stressed brown strain, CnCSDP transcripts were significantly up-regulated at 6 h in the blood, decreased dramatically in the mantle, while mostly maintained unchanged in the gill. Lastly, significantly positive correlation was found between the CnCSDP transcripts amount and total carotenoids content in the gill in both orange and brown strain. This study will be helpful for understanding the molecular mechanism underlying cold stress in noble scallop in the further.

Improvement in angular color uniformity of white light-emitting diodes using screen-printed multilayer phosphor-in-glass.

Angular color uniformity (ACU) is a key optical property of white light-emitting diodes (WLEDs) and high ACU is strongly demanded in illumination applications. In this paper, a multilayer phosphor-in-glass (PiG), which can be produced by the screen-printing method, is proposed to improve the ACU of LED packages. The screen-printing method provides a feasible scheme to produce multilayer, various-shaped PiG with a controllable pattern. Angular correlated color temperature (CCT) distributions of the LED packages with multilayer PiG are simulated numerically and measured experimentally. Optical performance of the LED package with optimized three-layer cone-shaped PiG is compared with that of packages with two-layer and one-layer PiG. The experimental measurements indicate that the deviation of angular CCT can be reduced from 761 to 171 K by cone-shaped PiG at average CCT of 6000 K. The results demonstrate that higher angular color uniformity can be achieved by LED packages with multilayer cone-shaped PiG.

[Inhibition of MCF-7/ADR cells by DOX-loaded pluronic-attached PAMAM dendrimer conjugate].

Pluronic modified polyamidoamine (PAMAM) conjugate (PF127-PAMAM) was prepared and the inhibiting effect of MDR against MCF-7/ADR was investigated with doxorubicin (DOX) as model drug. 1H NMR and FTIR spectra showed that the conjugate was synthesized successfully. Element analysis accurately measured that 27.63% amino of per PAMAM was modified by pluronic (PAMAM : PF127, 1 : 35.37 mole ratio). PF127-PAMAM showed an increased size and a reduced zeta potential compared to PAMAM. PF127-PAMAM had lower hemolytic toxicity and cytotoxicity due to the reduced zeta potential and the protection of PF127. Each PF127-PAMAM molecular could load 19.58 DOX molecules, and the complex exhibited sustained and pH-sensitive release behavior. PF127-PAMAM/DOX exhibited weaker cytotoxicity than free DOX in MCF-7 cells; while the complex showed much stronger reverse effect of drug resistance in MCF-7/ADR cells, and resistance reversion index (RRI) was as high as 33.15.

[Determination of trace amounts of nitrite and its chemical reaction kinetics].

A catalytic kinetic spectrophotometric method for the determination of nitrite, NO2(-)-S2O8(2-)-MR, was developed. It is based on the fading reaction of methyl red (MR) oxidized by potassium persulfate which can be catalyzed by NO2- in the medium of dilute HCl. The optimum experimental conditions were gained by combining single factor experiments with orthogonal experiments. Calibration curve, detection limit, precision, and anti-interference under the optimum experimental conditions were researched. Its kinetics principles and parameters were discussed. Its quantitative principle was investigated. The results show that the optimum experimental conditions of this method should be as follows: 1.0 mL 0.3 mol x L(-1) HCl, 1.0 mL 0.01 mol x L(-1) K2S2O8, 0.6 mL 0.2 g x L(-1) MR, reaction temperature 80 degrees C and reaction time 9 min. The principles for the quantitative determination of trace nitrite is that variation of MR concentration at the maximum absorption wavelength of 518 nm, ln(A0/A), shows a good linear relationship with the concentration of NO2- under the optimum experimental conditions. Its determination range is 0.01-0.80 mg x L(-1) and its detection limit is 0.007 mg x L(-1). The kinetic characteristics are that the reaction order in NO2- is 1 and the fading reaction is a pseudo first order reaction. Its apparent activation energy is 85.04 kJ x mol(-1). Its apparent rate constant is 0.021 4 min(-1), and the half-life is 32.39 min at 80 degrees C. The kinetic principle is that the variation of MR concentration is directly proportional to the concentration of NO2-, ln(A0/A) = kc(NO2-). This new method for the determination of trace nitrite has never previously been reported in the published literature so far. It is highly sensitive and selective. Most of the common ions don't interfere with the determination of nitrite. This method has the advantages of convenient operation and the regents used are cheap and nontoxic. It was applied to the determination of trace nitrite in food and water samples with satisfactory results.

[Study on infrared spectroscopy of cationic polyacrylamide initiated by ultraviolet].

Cationic Polyacrylamide P(AM-DAC-BA) was synthesized by UV initiation, with acrylamide (AM), acryloyloxyethyl trimethyl ammonium chloride (DAC), butyl acrylate (BA) as the monomers. P(AM-DAC-BA). UV spectroscopy and infrared spectroscopy were employed to study the structural characteristics. Attributions of typical infrared vibrational frequencies in AM/DAC/BA/P(AM-DAC-BA) were analysed. By comparing with infrared spectroscopy of the monomers, symmetrical characteristic of P(AM-DAC-BA) increasesd, and the infrared spectroscopy of polymerization product was simpler. The intrinsic viscosity increased with the increase in light intensity, BA content, photoinitiator concentration and illumination time. The groups of -CONH2, -COOCH2(C=O), -COOCH2--(C-O-C), -CH2--N(CH3 )3 group in AM, DAC, BA were selected as characteristic absorption peaks for studying. With the increase in light intensity and BA content, the characteristic peak areas increased. With the increase in photoinitiator concentration, the characteristic peak areas decreased. The characteristic peak areas decreased firstly and then increased with increasing the illumination time. But the corresponding characteristic IR absorption peaks of P(AM-DAC-BA) were similar, and the positions of characteristic peaks were basically the same.

Multifunctional droplet handling on surface-charge-graphic-decorated porous papers.

Developing a fluidic platform that combines high-throughput with reconfigurability is essential for a wide range of cutting-edge applications, but achieving both capabilities simultaneously remains a significant challenge. Herein, we propose a novel and unique method for droplet manipulation via drawing surface charge graphics on electrode-free papers in a contactless way. We find that opposite charge graphics can be written and retained on the surface layer of porous insulating paper by a controlled charge depositing method. The retained charge graphics result in high-resolution patterning of electrostatic potential wells (EPWs) on the hydrophobic porous surface, allowing for digital and high-throughput droplet handling. Since the charge graphics can be written/projected dynamically and simultaneously in large areas, allowing for on-demand and real-time reconfiguration of EPWs, we are able to develop a charge-graphic fluidic platform with both high reconfigurability and high throughput. The advantages and application potential of the platform have been demonstrated in chemical detection and dynamically controllable fluidic networks.