Theoretical Analysis and Experimental Verification on Flow Field of Piezoelectric Pump with Unsymmetrical Slopes Element

Regular valveless piezoelectric pumps have rectifying elements outside their chambers to produce net flow. These rectifying elements outside the chamber will increase the overall volume of the pump and prevent its minimization. Valveless piezoelectric pump with unsymmetrical slopes elements（USE）, proposed in this paper, differs from other valveless pumps in that it is easy to be minimized by developing the chamber bottom as such a rectifying element. In this research, the working principle of the proposed pump was analyzed first. Numerical models were thereby established and numerical simulation was conducted to the chamber flow field with the method of time-dependent velocity. The effects of the USEs on the flow field in the chamber were shown clearly in simulation. And the particular feature of flow field in the chamber was discovered. It behaves a complex flow field, in which strong turbulent occurs companying a lot of vortexes in different directions and different sizes. This feature is just opposite to what regular piezoelectric pumps expect： a moderate flow field. The turbulent flow could be used to have different liquids stirred and well mixed in the chamber to produce homogeneous solution, emulsion or turbid liquid. Meanwhile, numerical simulation also presents the effect of the angles difference of the two slopes upon the flow field, and upon the flow rate of the pump, which fits to the theoretical analysis. Experiments with the proposed pump were also conducted to verify the numerical results. In these experiments, six USEs with different slope angles were used for efficiency tests, which proved the validity and reliability of the numerical analysis. The data obtained from numerical analysis agree well with that from the experiments. The errors ranged from 4.4% to 14.8% with their weighted average error being 9.7%.

Analysis on Flow Field of the Valveless Piezoelectric Pump with Two Inlets and One Outlet and a Rotating Unsymmetrical Slopes Element

Typically,liquid pump and liquids mixer are two separate devices.The invention of piezoelectric pump makes it possible to integrate the two devices.Hower,the existing piezoelectric mixing-pumps are larger because the need the space outside the chamber,and another shortcome of them is that they cannot adjust the mixing ratio of two liquids.In this paper,a new piezoelectric pump being capable of integrating mixer and pump is presented,based on the theory of the piezoelectric pump with the unsymmetrical slopes element（USE）.Besides the features of two inlets and one outlet,the piezoelectric pump has a rotatable unsymmetrical slopes element（RUSE）.When the pump works,two fluids flow into the inlet channels respectively.Then the RUSE controls the ratio of the two flows by adjusting the flow resistances of the two inlet channels.The fluids form a net flow due to the USE principle,while they are mixed into a homogeneous solution due to strong turbulence flow field and complex vortices generated by RUSE in the chamber.And then the solution flows through the outlet.Firstly,the theoretical analysis on this pump is performed.Meanwhile,the flow field in the chamber is calculated and simulated.And then,the relationship between the flows of the two channels and the rotating angle of the RUSE is set up and analyzed.Finally,experiment with the proposed pump is carried out to verify the numerical results.A RUSE with 20° slope angle is used in the experiment.Four sets of data are tested with the RUSE at the rotating angles of 0°,6°,11°,and 16°,respectively,corresponding to the numerical models.The experimental results show that the empirical data and the theoretical data share the same trend.The maximum error between the theoretical flow and the experimental flow is 11.14%,and the maximum error between the theoretical flow ratio of the two inlets and the experimental one is 2.5%.The experiment verified the theoretical analysis.The proposed research provides a new idea for integration of micro liquids mixer and micro liquids pump.

K_2CO_3 catalyzed solvent-free synthesis of molecular tweezers containing chiral unsymmetrical urea unit under microwave irradiation

A facile,rapid and efficient method for the synthesis of molecular tweezers containing chiral unsymmetrical urea unit in solvent- free conditions using microwave was reported.

Study of An Unsymmetrical Shadow Mask PDP with High Luminous Efficacy

A new shadow mask plasma display panel （SMPDP） is presented in this article. The unsymmetrical geometry structure of the discharge cell is its main feature. A macro-cell with a ratio of 40：1 was designed and fabricated. The geometrical parameters and electrode＇s structure of the discharge cell of the unsymmetrical SMPDP were optimized. Compared with current SMPDP, its luminous efficiency was obviously improved. Then a 32-inch wide video graphics array （WVGA） unsymmetrical SMPDP with a luminous efficacy of 1.8 Lm/W was produced.

An efficient and mild protocol for the synthesis of unsymmetrical ureas in the absence of catalyst and additives

A new practical method for the synthesis of unsymmetrical ureas was achieved by reaction of phenylurea with primary and secondary amines under neutral and mild condition in very good yields. The reaction took place in refluxing dioxane and does not require any catalyst or additives.

Analytical solution to rock pressure acting on three shallow tunnels subjected to unsymmetrical loads

According to the interaction of three shallow tunnels with large section, the analytical solution to rock pressure has been derived and discussed. The load model is given when the bilateral tunnels are excavated. According to the model, the stresses of three tunnels and single tunnel are calculated and compared to analyze the distribution characteristics, where the stresses are influenced by controlling factors of clear distance, covering depth and inclination angle of ground surface. The results show that, in general, the bias distribution is more serious. Therefore, it is significant to settle down the load model of three shallow tunnels so as to determine the measure of reinforcement and design the structure of support. The model and results can be used as a theoretical basis in designation and further research of the three shallow tunnels.

Resistance Analysis of Unsymmetrical Trimaran Model with Outboard Sidehulls Configuration

The application of multi-hull ship or trimaran vessel as a mode of transports in both river and sea environments have grown rapidly in recent years.Trimaran vessels are currently of interest for many new high speed ship projects due to the high levels of hydrodynamic efficiency that can be achieved,compared to the mono-hull and catamaran hull forms.The purpose of this study is to identify the possible effects of using an unsymmetrical trimaran ship model with configuration（S/L） 0.1-0.3 and R/L=0.1-0.2.Unsymmetrical trimaran ship model with main dimensions： L=2000mm,B=200 mm and T=45 mm.Experimental methods（towing tank） were performed in the study using speed variations at Froude number 0.1-0.6.The ship model was pulled by an electric motor whose speed could be varied and adjusted.The ship model resistance was measured precisely by using a load cell transducer.The comparison of ship resistance for each configuration with mono-hull was shown on the graph as a function of the total resistance coefficient and Froude number.The test results found that the effective drag reduction could be achieved up to 17% at Fr=0.35 with configuration S/L=0.1.

Upper bound analytical solution for surrounding rock pressure of shallow unsymmetrical loading tunnels

By combining the results of laboratory model tests with relevant flow rules, the failure mode of shallow unsymmetrical loading tunnels and the corresponding velocity field were established. According to the principle of virtual power, the upper bound solution for surrounding rock pressure of shallow unsymmetrical loading tunnel was derived and verified by an example. The results indicate that the calculated results of the derived upper bound method for surrounding rock pressure of shallow unsymmetrical loading tunnels are relatively close to those of the existing "code method" and test results, which means that the proposed method is feasible. The current code method underestimates the unsymmetrical loading feature of surrounding rock pressure of shallow unsymmetrical loading tunnels, so it is unsafe; when the burial depth is less or greater than two times of the tunnel span and the unsymmetrical loading angle is less than 45°, the upper bound method or the average value of the results calculated by the upper bound method and code method respectively, is comparatively reasonable. When the burial depth is greater than two times of the tunnel span and the unsymmetrical loading angle is greater than 45°, the code method is more suitable.

Unsymmetrical load effect of geologically inclined bedding strata on tunnels of passenger dedicated lines

In order to study the unsymmetrical load effect in geological bedding strata for the Muzhailing tunnel on the Lanzhou-Chongqing passenger dedicated line in China, we investigated the deformation, mechanical response and pressure of the surrounding rock and the mechanical characteristics of bolts of the tunnel. The results suggest that open zones appear at arch and invert where joints open up, when layered stratum is horizontal, or when the dip angle of in- clined bedding is small. Open zones occur perpendicular to a joint. The failure mode is bending disjunction at the arch tain shear displacement, and lead to obvious geological bedding unsymmetrical load. The failure mode is shear damage. For the joint dip angle in the range of 75-90°, the failure mode is flexural crushing at the wall and vertical shear rup- ture above the arch. The restraining effect of two sides weakens for vertical dip. On the whole, shear failure instabilitytrend would occur and the tunnel collapses evenly. When the angle between the bolt and structure plane is greater than 23°, bolts can enhance the shearing stiffness of joint plane. Unfortunately, in the general purpose graph of tunnel for 250 km/h of passenger dedicated lines, the bolts have equal length and spacing. The rationale behind this is worthy offurther study. For inclined bedding, the surrounding rock pressure at the left wall is more than that at the right wall. In addition, lining is likely to be damaged at left shoulder and side wall. With the dip angle increasing, the unsymmetrical load gradually achieves symmetry. Asymmetry design for support is recommended to reduce the unsymmetrical load on lining disturbed by excavation.

Synthesis and Thermal Decomposition Kinetics of La(Ⅲ) Complex with Unsymmetrical Schiff Base Zwitterion Ligand

A new unsymmetrical solid Schiff base (LLi) was synthesized using L-lysine, o-vanillin and 2-hydroxy-l-naphthaldehyde. Solid La(Ⅲ) complex of this ligand [LaL(NO3)](NO3)·2H2O was prepared and characterized by elemental analyses, IR, UV and molar conductance. The thermal decomposition kinetics of the complex for the second stage were studied under non-isothermal condition by TG and DTG methods. The kinetic equation may be expressed as: dα/dt=A·e-E/RT·(1-α)2. The kinetic parameters(E, A), activation entropy S≠ and activation free-energy G≠ were also gained.

Synthesis, Characterization and Antibacterial Activity of New Ln(Ⅲ) Complex with Unsymmetrical Schiff Base Ligand

A new unsymmetrical Schiff base ligand (H_2LLi) was synthesized using L-lysine, o-vanillin and salicylaladyde. Three solid metal complexes of this ligand [Ln(H_2L)(NO_3)] NO_3·2H_2O (Ln=Sm, Ho, Tm) were prepared and characterized by elemental analyses, IR spectra, UV spectra, TG-DTG and molar conductance. The ligand synthesized are chelating agent. The nitrogen atoms of Schiff base, oxygen atoms of hydroxybenzene, methoxide and carboxyl are all coordinated to the metal ions. Carboxyl and the nitrate ion within the coordination sphere are coordinated to the metal ion in a mondentate or bidentate fashion. Water molecules are lied in crystal substances. The antibacterial activity of the ligand and its complexes was also studied. The antibacterial experiments indicate that they have antibacterial activity to E. coli, S. aureus, B. subtilis and the complexes have higher activity than the ligand.

1/2 SUBHARMONIC RESONANCE OF A SHAFT WITH UNSYMMETRICAL STIFFNESS

The 1/2 subharmonic resonance of a shaft with unsymmetrical stiffness is studied. By means of the Hamilton's principle the nonlinear differential equations of motion of the rotating shaft are derived in the rotating rectangular coordinate system. Transforming the equations of motion from rotating coordinate system into stationary coordinate system and introducing a complex variable, the equation of motion in complex variable form is obtained, in which the stiffness coefficient varies periodically with time. It presents a nonlinear oscillation system under parametric excitation. By applying the method of multiple scales (MMS) the averaged equation, the bifurcating response equations and local bifurcating set are obtained. Via the theory of singularity, the stability of constant solutions is analyzed and bifurcating response curves are obtained. This study shows that the rotating shaft has rich bifurcation phenomena.

Novel insights into conjugation of antitumor-active unsymmetrical bisacridine C-2028 with glutathione:Characteristics of non-enzymatic and glutathione S-transferase-mediated reactions

Unsymmetrical bisacridines(UAs) are a novel potent class of antitumor-active therapeutics.A significant route of phase II drug metabolism is conjugation with glutathione(GSH),which can be non-enzymatic and/or catalyzed by GSH-dependent enzymes.The aim of this work was to investigate the GSHmediated metabolic pathway of a representative UA,C-2028.GSH-supplemented incubations of C-2028 with rat,but not with human,liver cytosol led to the formation of a single GSH-related metabolite.Interestingly,it was also revealed with rat liver microsomes.Its formation was NADPH-independent and was not inhibited by co-incubation with the cytochrome P450(CYP450) inhibitor 1-aminobenzotriazole.Therefore,the direct conjugation pathway occurred without the prior CYP450-catalyzed bioactivation of the substrate.In turn,incubations of C-2028 and GSH with human recombinant glutathione S-transferase(GST) P1-1 or with heat-/ethacrynic acid-inactivated liver cytosolic enzymes resulted in the presence or lack of GSH conjugated form,respectively.These findings proved the necessary participation of GST in the initial activation of the GSH thiol group to enable a nucleophilic attack on the substrate molecule.Another C-2028-GSH S-conjugate was also formed during non-enzymatic reaction.Both GSH S-conjugates were characterized by combined liquid chromatography/tandem mass spectrometry.Mechanisms for their formation were proposed.The ability of C-2028 to GST-mediated and/or direct GSH conjugation is suspected to be clinically important.This may affect the patient’s drug clearance due to GST activity,loss of GSH,or the interactions with GSH-conjugated drugs.Moreover,GST-mediated depletion of cellular GSH may increase tumor cell exposure to reactive products of UA metabolic transformations.

Synthesis, Characterization and Antibacterial Activity of New Ln(Ⅲ) Complexes with an Unsymmetrical Schiff Base Ligand

A new unsymmetrical Schiff base ligand (H2LLi) was synthesized using L-lysine, salicylaldehyde and 2-hydroxy-1-naphthaldehyde. Three solid metal complexes of this ligand \[Ln(H2L)(NO3)\] NO3·2H2O (Ln=La, Sm, Ho) have been prepared and characterized by elemental analyses, IR spectra, UV spectra, TG-DTG and molar conductance. The antibacterial activities of the ligand and its complexes are also studied. The antibacterial experiments indicate that the ligand and its complexes possess antibacterial activity against Escherichia coli, Staphylococcus aureus and Bacillus subtilis and that the complexes have higher activity than those of the ligand.

Unsymmetrical Quantum Key Distribution Using Tripartite Entanglement

An unsymmetrical quantum key distribution protocol is proposed, in which Greenherger-Horne-Zeilinger （GHZ） triplet states are used to obtain the secret key. Except the lost qubits due to the unperfectness of the physical devices, the unsymmetrical characteristic makes all transmitted qubits useful. This leads to：an excellent efficiency, which reaches 100% in an ideal case. The ＇security is studied from the aspect of information theory. By using the correlation of the GHZ tripartite entanglement state, eavesdropping can be easily checked out, which indicates that the presented protocol is more secure.

SYNTHESIS AND CHARACTERIZATION OF FLUORINATED POLYAMIDES DERIVED FROM UNSYMMETRICAL DIAMINES CONTAINING THE PHTHALAZINONE MOIETY

A novel unsymmetrical fluorinated diamine monomer with kink non-coplanar heterocyclic structures, 1,2-dihydro- 2-（4-amino-2-trifluoromethyophenyo）-4-[4-（4-amino-2-trifluoromethyophenoxy）phenyo]（2H）phthaoazin-1-oneo was prepared through the nucleophilic substitution reaction of 1-trifluromethyl-2-chloro-5-nitrobenzene with 1,2-dihydro-4-（4- hydroxyphenyl）（2H）phthalazin-l-one in the presence of potassium carbonate, followed by catalytic reduction with hydrazine and Pd-C. A series of new fluorinated polyarnides were synthesized by the phosphorylation polyamidation of the fluorinated diamine with various dicarboxylic acids. The prepared polymers were obtained in quantitative yields with moderately and high inherent viscosities （0.47-0.87 dL/g）. They were all amorphous and readily soluble in various polar aprotic solvents such as N-methyl-2-pyrrolidone （NMP）, N,N-dimethylformamide （DMF）, N,N-dimethylacctamide （DMAc）, pyridine （Py） and m-cresol at room temperature. These fluorinated polyamides have excellent thermal properties. The glass transition temperatures were all above 300℃. The 5% and 10% weight loss temperatures were in the range of 437-466℃ and 482-525℃ in nitrogen atmosphere, respectively.

Stress dilatancy analysis of shallow tunnels subjected to unsymmetrical pressure

Numerical simulation using finite differential code was conducted for the single line railway and four-lane road shallow tunnels subjected to unsymmetrical pressure. The mechanical behavior of weak rock mass was studied considering the influences of stress dilatancy on the failure mechanisms, and the results of numerical simulation were compared with the analytical solutions in specifications. The results show that the dilatancy angle has great influences on the surrounding rock displacement and the shape of failure face for the shallow tunnels. When the dilatancy angle equals zero, the failure face of the surrounding rock forms and extends to the ground surface. With the dilatancy angle increasing, the loose region decreases gradually, and failure surface discontinues. When the dilatancy angle equals the friction angle, the loose region is only distributed in a small range around the crown and sidewalls. On the side of smaller buried depth, the difference of break angle between numerical simulation and the code is less than 10% for single line railway tunnels with the dilatancy angle of zero. However, for the four-lane road tunnels, the difference reaches 20.8%. On the side of larger buried depth, the break angles are smaller than those by the code, the difference reaches 16.8% for single line railway tunnels, and 13.8% for four-lane road tunnels. With the dilatancy angle increasing, especially the dilatancy angle approximating to internal friction angle, it is on safe side to calculate the break angle using the analytical solution method of specifications. Therefore, the influence of stress dilatancy should be considered while determining the failure mechanisms of shallow tunnels subjected to unsymmetrical pressure in weak rocks.

A Novel Method of Preparing Unsymmetrical Thioether from Disulfides

The disulfides reacted with zinc in DMF, followed by alkyl halides, giving unsymmetrical thioether in excellent yields. This reaction takes place under mild and neutral conditions.

Synthesis and characterization of a novel series of unsymmetrical porphyrins

A novel series of unsymmetrical porphyrins with aldehyde group at the terminal of the linkage which connected to meso-phenyl through acylamide bond have been synthesized and structurally characterized by IR, (1)H NMR, MS, UV–vis, fluorescence.

UNSYMMETRICAL LARGE DEFORMATION PROBLEM OF ORTHOTROPIC PLATES

Based upon the theory of ardsotropic plates, the unsymmetrical large deformation equations of orthotropic circular plates were derived. By using Fourier series, the partial differential equations of this problem can be transformed into sets of nonlinear differential equations . And the procedure to solve the problem using the iterative method is given .