A study on the biological detection chip through the use of PDMS lens for the reinforcement of fluorescence receiving signal

In this study, MEMS process technology is adopted to produce microfluidic chip and PDMS lens. SU-8 thick film photo resist is coated onto silicon wafer surface in two times of spin coating, then through lithography and mold transfer technology, PDMS chip of minimal line width 100 μm and thickness 200 μm is printed. In fluorescence detection aspect, we use objective lens to couple laser optical source to optical fiber, and then have it incident to excite fluorescence sample, the excited fluorescence then passes through filter and detected by optical detector of experiment group and spectrophotometer of reference group. From the experiment result, the Hex fluorescence detection limit of the system is verified to be 1 pmol/5 μl. In addition, we have integrated PDMS lens into microfluidic chip to make generalized detection experiment, it was found that the signal measured by optical embedded type is higher than that of non-embedded type. Meanwhile, the microfluidic chip with double concave lens (135°) and10 mm PDMS focusing lens can be utilized to obtain optimal fluorescence receiving effect. The fluorescence intensity is raised by 2–3 times, and the measurement limit is lowered to 100 fmol/5 μl.     

Thermoelastic damping in torsion microresonators with coupling effect between torsion and bending

Predicting thermoelastic damping (TED) is crucial in the design of high Q MEMS resonators. In the past, there have been few works on analytical modeling of thermoelastic damping in torsion microresonators. This could be related to the assumption of pure torsional mode for the supporting beams in the torsion devices. The pure torsional modes of rectangular supporting beams involve no local volume change, and therefore, they do not suffer any thermoelastic loss. However, the coupled motion of torsion and bending usually exists in the torsion microresonator when it is not excited by pure torque. The bending component of the coupled motion causes flexural vibrations of supporting beams which may result in significant thermoelastic damping for the microresonator. This paper presents an analytical model for thermoelastic damping in torsion microresonators with the coupling effect between torsion and bending. The theory derives a dynamic model for torsion microresonators considering the coupling effect, and approximates the thermoelastic damping by assuming the energy loss to occur only in supporting beams of flexural vibrations. The thermoelastic damping obtained by the present model is compared to the measured internal friction of single paddle oscillators. It is found that thermoelastic damping contributes significantly to internal friction for the case of the higher modes at room temperature. The present model is validated by comparing its results with the finite-element method (FEM) solutions. The effects of structural dimensions and other parameters on thermoelastic damping are investigated for the representative case of torsion microresonators.     

Low‐loss aluminium nitride thin film for mid‐infrared microphotonics

Mid‐infrared (mid‐IR) microphotonic devices including (i) straight/bent waveguides and (ii) Y‐junction beam splitters are developed on thin films of CMOS‐compatible sputter deposited aluminum nitride (AlN)‐on‐silicon. An optical loss of 0.83 dB/cm at λ = 2.5 µm is achieved. In addition, an efficient mid‐IR 50:50 beam splitter is demonstrated over 200 nm spectral bandwidth along with a <2% power difference between adjacent channels. With the inherent advantage of an ultra‐wide transparent window (ultraviolent to mid‐IR), our AlN mid‐IR platform can enable broadband optical networks on a chip.     

ChemInform Abstract: A Three‐Dimensional Aromatic B6Li8 Complex as a High Capacity Hydrogen Storage Material.

On the basis of theoretical calculations (B3LYP/6‐311+G), the title complex is predicted to be aromatic and a promising hydrogen storage material with a gravimetric density of up to 24%.     

Thermal and Mechanical Properties of Epoxy/Carbon Fiber Composites Reinforced with Multi-walled Carbon Nanotubes

Multi-scale hybrid composite laminates of epoxy/carbon fiber (CF) reinforced with multi-walled carbon nanotubes (MWCNTs) were fabricated in an autoclave. For laminate fabrication, 0.5 wt% of pristine MWCNTs or silane-functionalized MWNCTs (f-MWCNTs) were dispersed into a diglycidyl ether of bisphenol-A epoxy system and applied on the woven carbon fabric. The neat epoxy/CF composite and the MWCNTs-reinforced epoxy/CF hybrid composites were characterized by thermogravimetric analysis (TGA), thermomechanical analysis (TMA), tensile testing, and field emission scanning electron microscopy (FE-SEM). A significant improvement in initial decomposition temperature and glass transition temperature of epoxy/CF composite was observed when reinforced with 0.5 wt% of f-MWCNTs. The coefficient of thermal expansion (CTE), measured by TMA, diminished by 22% compared to the epoxy/CF composite, indicating an improvement in dimensional stability of the hybrid composite. No significant improvement in tensile properties of either MWCNTs/epoxy/CF composites was observed compared to those of the neat epoxy/CF composite.     

Reflexive Property of Rings

Mason introduced the reflexive property for ideals, and then this concept was generalized by Kim and Baik, defining idempotent reflexive right ideals and rings. In this article, we characterize aspects of the reflexive and one-sided idempotent reflexive properties, showing that the concept of idempotent reflexive ring is not left-right symmetric. It is proved that a (right idempotent) reflexive ring which is not semiprime (resp., reflexive), can always be constructed from any semiprime (resp., reflexive) ring. It is also proved that the reflexive condition is Morita invariant and that the right quotient ring of a reflexive ring is reflexive. It is shown that both the polynomial ring and the power series ring over a reflexive ring are idempotent reflexive. We obtain additionally that the semiprimeness, reflexive property and one-sided idempotent reflexive property of a ring coincide for right principally quasi-Baer rings.     

On Sums of Coefficients of Products of Polynomials

We study the nilpotency of the sums of all coefficients of some sorts of products of polynomials over reversible, IFP, and NI rings, and introduce an SCN ring as a generalization. We characterize SCN rings in relation with related ring properties, and also provide several useful properties and ring extensions of SCN rings.     

On minimal strongly prime ideals

In this paper we give some characterizations of a ring Rwhose unique maximal nil ideal N _r (R) coincides with the set of all its nilpotent elements N(R) by using its minimal strongly prime ideals.     

Syntheses,Photophysics, and Application of Iridium(III) Phosphorescent Emitters for Highly Efficient,Long‐Life Organic Light‐Emitting Diodes

Long live the OLED! Rational design and synthesis of Ir^III complexes bearing two cyclometalated ligands (C N) and one 2‐(diphenylphosphino)phenolate chelate (P O) as well as the corresponding Ir^III derivatives with only one (C N) ligand and two P O chelates are reported. According to the observed photophysical data, a P O ligand is found to be able to fine‐tune the light‐emitting electronic transition of these complexes.