On-chip detection of a single nucleotide polymorphism without polymerase amplification

A nanoparticle-assembled photonic crystal （PC） array was used to detect single nucleotide polymorphism （SNP）. The assay platform with PC nanostructure enhanced the fluorescent signal from nanoparticle-hybridized DNA complexes due to phase matching of excitation and emission. Nanoparticles coupled with probe DNA were trapped into nanowells in an array by using an electrophoretic particle entrapment system. The PC/DNA assay platform was able to identify a 1 base pair （bp） difference in synthesized nucleotide sequences that mimicked the mutation seen in a feline model of human autosomal dominant polycystic kidney disease （PKD） with a sensitivity of 0.9 fg/mL （50 aM）-sensitivity, which corresponds to 30 oligos/array. The reliability of the PC/DNA assay platform to detect SNP in a real sample was demonstrated by using genomic DNA （gDNA） extracted from the urine and blood of two PKD-wild type and three PKD positive cats. The standard curves for PKD positive （PKD＋） and negative （PKD-） DNA were created using two feline-urine samples. An additional three urine samples were analyzed in a similar fashion and showed satisfactory agreement with the standard curve, confirming the presence of the mutation in affected urine. The limit of detection （LOD） was 0.005 ng/mL which corresponds to 6 fg per array for gDNA in urine and blood. The PC system demonstrated the ability to detect a number of genome equivalents for the PKD SNP that was very similar to the results reported with real time polymerase chain reaction （PCR）. The favorable comparison with quantitative PCR suggests that the PC technology may find application well beyond the detection of the PKD SNP, into areas where a simple, cheap and portable nucleic acid analvsis is desirable.     

Fabrication of Bulk Targets of MgB2 with Stoichiometric and Nonstoichiometric Contents

Powder of magnesium diboride was obtained by solid phase reaction of mixture of magnesium （〉 99% pure） and amorphous boron （〉 99% pure） powders at 650-900 ℃ temperatures in inert atmosphere. During synthesis process main attention was paid. to removing oxide layer of surfaces of powder particles by organic solvents in Glovebox, where concentration of oxygen and water steam is less than 5 ppm. Homogenization and activation of powders were conducted in a planetary nano-mill by WC balls in an inert area. Pressing of the obtained powders was conducted in an argon atmosphere. MgB2 nonstoichiometric powders contained excess boron and magnesium, Magnesium hydride was used as source of excess boron, which is fragile compound and easy to grind in nano-mill. It decomposites with metallic magnesium and hydrogen up to 280 ℃ temperature. Commercial magnesium diboride powder （Aldrich, 〉 99%） was used for fabrication of MgB2 bulk targets. Powders systems of MgB2-Mg, MgB2-MgH2, MgB2-B homogenized by nano-mill in Glove box was used for fabrication of composites with nonstoichiometric contents. The targets were cylinders with diameters of 27-52 mm and height of 5-15 mm. Consolidation of pressed powdery composites was conducted in argon atmosphere. Synthesis of MgB2 from mixture of magnesium and amorphous boron powders and simultaneous consolidation were conducted by hot pressing （HP） method. Phase content of the obtained targets were established by XRD method after dry polishing. Superconducting characteristic of the obtained samples were measured by vibrational magnetometer. The superconducting transition with an onset at 39 K was observed in a good agreement with the results of the other groups obtained on samples prepared by conventional techniques. The phase exists near the nominal composition without a significant homogeneity range.     

Layer‐by‐Layer Approach to (2+1)D Photonic Crystal Superlattice with Enhanced Crystalline Integrity

Large‐area polystyrene (PS) colloidal monolayers with high mechanical strength are created by a combination of the air/water interface self‐assembly and the solvent vapor annealing technique. Layer‐by‐layer (LBL) stacking of these colloidal monolayers leads to the formation of (2+1)D photonic crystal superlattice with enhanced crystalline integrity. By manipulating the diameter of PS spheres and the repetition period of the colloidal monolayers, flexible control in structure and stop band position of the (2+1)D photonic crystal superlattice has been realized, which may afford new opportunities for engineering photonic bandgap materials. Furthermore, an enhancement of 97.3% on light output power of a GaN‐based light emitting diode is demonstrated when such a (2+1)D photonic crystal superlattice employed as a back reflector. The performance enhancement is attributed to the photonic bandgap enhancement and good angle‐independence of the (2+1)D photonic crystal superlattice.     

Studies of Ion-Transport Mechanisms in PEM Based on PVA ＋ H3PO2 ＋ H2O

The ionic conductivity for proton exchange membranes （PEM）, based on the PVA ＋ H3PO2 ＋ H2O polymer system was studied as a function of temperature. The dc-conductivity of all compositions increases rapidly with the acid concentration, between 10.3 and 101 S·cm^-1as the acid concentration was increased. Hydrated membranes showed an Arrhenius-type behavior in their conductivities, with an activation energy between 0.20 and 0.10 eV as the acid concentration was increased. When the relative humidity varies between 25% and 92% at room temperature, water uptake increases dc-ionic conductivity varying between 10-3 and 10-2 S·cm^-1 for the best performing composition （P/OH = 0.3）. The plot of the conductance of the polymer electrolyte as a function of % RH follows a sigmoidal trend. This functional variation was found to be strictly correlated with a similar trend of the film capacitance through a relationship derived from the Onsager equation for liquid electrolytes. Thus, the results support the presence of a （H3PO2/H2O） separated liquid phase in the polymer.     

Synthesis of green emitting and transparent zn2siO4:mn2+ thin film phosphors on 2D photonic crystal patterned quartz substrates

Zn2SiO4:Mn2+ thin film phosphors (TFPs) have been synthesized by RF magnetron sputtering, using a single multicomponent stoichiometric target. And 2D photonic crystal patterns were introduced on a quartz substrate to enhance the light extraction efficiency. In order to introduce 2D photonic crystal patterns on a quartz substrate, nanosphere lithography was used. Polystyrene spheres, with diameter of 330 nm, were transferred on the quartz substrate and subsequently were served as an etch mask. Quartz substrates were patterned by CF4 gas-based reactive ion etching. Zn2SiO4:Mn2+ were deposited on that 2D photonic crystal patterned quartz substrate and the effect of height of photonic crystal layers were investigated. The light extraction efficiency of Zn2SiO4:Mn2+ thin film phosphors deposited on the photonic crystal patterned quartz substrate was enhanced three times to compared with that of flat Zn2SiO4:Mn2+ thin film phosphors due to the Bragg diffraction and leaky mode caused by PCLs. Transmittance of Zn2SiO4:Mn2+ TFPs deposited on the photonic crystal patterned substrate was high enough, above 70% in the visible light region with respect to that of quartz substrate.     

Characteristics of the Oxygen Function in High Tc Copper Oxide Superconductors

Comments on the studies of the oxygen functions in high Tc copper oxide superconductors and the effects of isotope were made. And the characteristics of the oxygen functions in high Tc copper oxide superconductors were discussed on the basis of the dual-body structure model of superconductors. It is pointed out that the characteristics of the oxygen functions in high Tc copper oxide superconductors are that they influence the crystal structure and the carriers density and participate in the electron phonons coupling.     

Photonic polymer replicas from distributed Bragg reflectors structured porous silicon

Well defined 1-dimentional (1-D) photonic crystals of polymer replicas have been successfully obtained. DBR porous silicon containing nanometer-scale pores are prepared by an anodic electrochemical etch of p(++)-type silicon wafer. The resulting DBR porous silicon film removed from the substrate by applying an electropolishing current has been thermally oxidized in the furnace at 400 degrees C for 3 h. Oxidized DBR PSi/polystyrene composite films are prepared by casting of polymer solution onto a free-standing porous silicon photonic crystal layer. Flexible photonic polymer replicas have been prepared after the removal of oxidized DBR PSi matrix in HF/H2O mixture solution. Polymer replicas exhibit a sharp resonance in the reflectivity spectrum. Optical characteristics of photonic polymer replica indicate that the surface of polymer film has a negative structure of DBR PSi. This replica is stable in aqueous solutions for several days without any degradation.     

Elaboration and Properties of Starch-Based Bio-Material Films Using Different Solvent Systems

Nowadays many studies have been focusing on the development of biomaterials obtained from renewable resources to replace fossil based plastics. The famous example is starch which is produced by a wide variety of plants as energy reserve and is available in abundance at a very competitive price. It can easily be transformed into thermoplastic starch （TPS） by addition of a plasticizer. However, TPS suffers from several limitations, such as poor mechanical properties and water sensitivity which did not permit its use in large practical applications. In this study, different formulations, containing commercial corn starch and plasticizers were prepared by the film casting method, after gelatinization of starch in hot aqueous suspensions. To obtain flexible films, two plasticizers were used： glycerol and dioctyl phthalate （DOP）. The fact that the DOP displayed an exceptionally poor water affinity, three co-solvents, methanol, ethanol and acetone were added in the aim to improve its solubility. The obtained materials were tested considering the water resistance measured at 25 and at 50 ℃, mechanical properties in tension and the differential scanning thermal analysis （DSC）. From the obtained results, it seems that the solvent system as well as the plasticizers used affects considerably the properties of the resulting materials.     

New Composite Electrode Material Based on Glassy Carbone/Polythiophene/MnO2

In this paper, it presents the work which consists to develop and characterize a modified electrode with a conductive polymer film, poly [3-methyl thiophene] then incorporating manganese dioxide MnO2 into the film. The deposition of the polymer film on the surface of the glassy carbon electrode is realized by the electrochemical oxidation of the monomer [3-methyl thiophene] in an organic medium. Then the electrode obtained was immersed in a solution containing ions Mn4~ to introduce into the polymeric film. The technique of insertion of manganese ions is performed by interaction with the polymer film. The electrochemical oxidation of the modified electrode in an aqueous medium will precipitate the manganese dioxide in the form of particles in the polymer film. In this study, it was found that several parameters affect the amount of manganese dioxide introduced as the pH of the medium and the thickness of the polymer film.     

Fabrication and characterisation of CdSe photonic structures from self-assembled templates

We demonstrate here a method to fabricate CdSe photonic crystal from a very cheap fabrication route of templated self-assembly. The hexagonal close-packed photonic crystals are formed by the electrochemical growth of CdSe through the interstitial spaces between polymer nano/micro sphere templates. The confocal voids containing photonic crystals can be made either interconnected or well separated, with high uniformity. Structural and optical characterisation confirms the good quality of electrochemically grown CdSe. These cheaply fabricated 2D photonic crystals provide a wide range of opportunities for optoelectronic devices.     

A thermally tunable inverse opal photonic crystal for monitoring glass transition

An optical method was developed to monitor the glass transition of the polymer by taking advantage of reflection spectrum change of the thermally tunable inverse opal photonic crystal. The thermally tunable photonic bands of the polymer inverse opal photonic crystal were traceable to the segmental motion of macromolecules, and the segmental motion was temperature dependent. By observing the reflection spectrum change of the polystyrene inverse opal photonic crystal during thermal treatment, the glass transition temperature of polystyrene was gotten. Both changes of the position and intensity of the reflection peak were observed during the glass transition process of the polystyrene inverse opal photonic crystal. The optical change of inverse opal photonic crystal was so large that the glass transition temperature could even be estimated by naked eyes. The glass transition temperature derived from this method was consistent with the values measured by differential scanning calorimeter.     

基于分子传感材料的智能医疗产品设计研究

目的 运用光子晶体新材料作为分子传感器,针对糖尿病患者自我监测产品进行研究再设计工作.方法 以智能高分子材料——光子晶体为研究对象,从糖尿病患者自我监测需求出发,采用以智能家居产品设计思考为导向的研究方式,基于德拜衍射相关理论,对光子晶体分子传感器及其设计应用进行解析研究,将新材料技术与智能家居产品设计相结合,解决糖尿病患者的日常居家葡萄糖监测需求.结论 以化学新材料特性为出发点,将强化实用功能、提高易用程度及强调用户体验作为研究基础,依据化学材料特性与实验技术原型相结合,功能需求与艺术形式相统一的方式,设计出基于光子晶体材料的糖尿病患者自我监测产品,并最终投入生产使用.     

Dispersion of electromagnetic waves in a resonant opal photonic crystal filled with Al2O3:Cr3+

We have studied the band structure and group velocity of electromagnetic waves in an opal photonic crystal filled with Al₂O₃:Cr³⁺. The results demonstrate that, when a resonance state of the chromium ion falls within the band gap of an unfilled photonic crystal, the group velocity of electromagnetic waves decreases anomalously. We have calculated the dispersion curves and frequency dependences of the group velocity of electromagnetic waves in an opal photonic crystal filled with Al₂O₃:Cr³⁺.     

NaGd(WO4)2:Yb3+/Tm3+反蛋白石光子晶体的制备与上转换发光调制研究

三维光子晶体具有长程有序的结构特点, 在可见和近红外光谱范围内有着广泛的应用。光子晶体的一个重要性质是其对嵌入其中的发光中心自发辐射具有调制作用。本研究利用自组装和模板辅助法制备高质量的三维NaGd(WO₄)₂:Yb³⁺/Tm³⁺反蛋白石光子晶体, 探究了光子带隙对Tm³⁺离子上转换荧光发射与发光动力学的调制作用。通过对比分析发现, 由于反蛋白石光子晶体独特的周期性大孔结构和光子带隙效应, 处于光子带隙内的Tm³⁺离子¹G₄-³H₆的发光强度被抑制约45%, 自发辐射速率(SDR)被抑制约30%, 同时上转换局域热效应得到有效的调制。本实验结果对探索新型高效稀土掺杂上转换发光材料和提高上转换发光效率有指导意义。     

Modified annular photonic crystals for enhanced band gap properties and iso-frequency contour engineering

In this paper complete photonic bandgap (PBG) and iso-frequency contours (IFCs) of two-dimensional modified annular photonic crystals (MAPC) for four different configurations are numerically studied and calculated by applying plane wave expansion method. The effects of opto-geometric parameters of the designed unit-cell structures are clearly demonstrated in terms of opening frequency gaps and appearing tilted band curves. Optimal structures with large PBGs are reported. The absolute gap can be increased to a maximum value of Δω/ω=0.1766(2πc/a), where a is the lattice constant and c is the speed of light. The incorporation of additional parameters inside the unit cell of photonic crystal enables an extra degree of freedom for controlling the flow of light even in the absence of structural defects. The finite-difference time-domain method is utilized to depict the MAPC's light deflection and guiding characteristics. These proposed structures are likely to be promising candidates for applications that require polarization insensitivity due to providing large complete PBGs and possessing special IFCs.     

Micro-indentation of metallic photonic crystals: experimental and numerical investigations

Photonic crystals (PCs) are synthetic materials that are used to control light propagation. PCs have a frequency bandgap where light is forbidden to propagate. This bandgap is strongly tied to the microstructure of the photonic crystal. Three-dimensional tungsten photonic crystal in a Lincoln-log microstructure has been suggested as a strong alternative filter in photovoltaic cells with significantly high power efficiency. PCs have also been suggested as sensors for submicron damage. Therefore, mechanical characterization of three-dimensional photonic crystals becomes of interest. Here we report on mechanical characterization of tungsten PC using means of micro-indentation. We also present a three-dimensional finite element simulation of the structural response of a Tungsten photonic crystal under micro-indentation load. Stresses developed in the PC can be used to quantify the level of damage in the crystal. We compare our simulation results with the experimental observations of a Vickers and Knoop micro-indentation experiments of tungsten PC. The FE models were proven able to simulate the mechanical response of the PC with a good accuracy. The calibrated FE models can be further used to realize the mechanical behavior of PC under different thermal and mechanical stresses when used as filters in photovoltaic cells or to simulate the effect of damage in PC sensors.     

Inside Front Cover: Experimental Evidence for Superprism Effects in Three‐Dimensional Polymer Photonic Crystals (Adv. Mater. 2/2006)

The inside cover illustrates the highly dispersive propagation of light in a three‐dimensional polymer photonic crystal. White light is coupled into a woodpile structure and split into its wavelength components due to the frequency‐dependent dispersion properties of the structure. This superprism effect is orders of magnitudes higher than in a conventional glass prism and is caused by the strong anisotropy of the dispersion surface at frequencies slightly above the photonic bandgap. In work reported on p. 221, Serbin and Gu fabricated these woodpile structures operating in the near‐infrared wavelength range by means of two‐photon polymerization and give theoretical and experimental evidence for the superprism effect in these low‐index photonic‐crystal structures.     

Alignment of crystal orientations of the multi-domain photonic crystals in Parides sesostris wing scales

It is known that the wing scales of the emerald-patched cattleheart butterfly, Parides sesostris, contain gyroid-type photonic crystals, which produce a green structural colour. However, the photonic crystal is not a single crystal that spreads over the entire scale, but it is separated into many small domains with different crystal orientations. As a photonic crystal generally has band gaps at different frequencies depending on the direction of light propagation, it seems mysterious that the scale is observed to be uniformly green under an optical microscope despite the multi-domain structure. In this study, we have carefully investigated the structure of the wing scale and discovered that the crystal orientations of different domains are not perfectly random, but there is a preferred crystal orientation that is aligned along the surface normal of the scale. This finding suggests that there is an additional factor during the developmental process of the microstructure that regulates the crystal orientation.     

Photonic bandgaps of different unit cells in the basic structural unit of germanium-based two-dimensional decagonal photonic quasi-crystals

Based on the infrared optical material germanium, in the basic structural unit of a two-dimensional decagonal photonic quasi-crystal, photonic bandgaps of four square unit cells with a scattering radius in the range of [0,0.3a] have been calculated within two cases of construction (i.e., air cylinders arranged in germanium and germanium cylinders arranged in air) by using the plane wave expansion method. In considering the Bragg-like scattering effect in two-dimensional photonic quasi-crystals as the elastic collision in physics, we put forward the photonic bandgap impact function F=q(1)q(2)q(3)επr(2) for the first time, to the best of our knowledge. A certain unit cell structure shares some similar photonic bandgap properties with a periodic structure. For a certain structure of the unit cell, the center frequency change trends of the photonic bandgap and the type of photonic bandgap generated are not related with the period of the photonic crystal, but with the relative dielectric constant and the construction, respectively. Different unit cell structures own different photonic bandgap structures. This occurs because the high degree of rotational symmetry of the quasi-periodic structure and weak long-range order of the basic structural unit lead to different Bragg-like scattering effects within the unit cell structures.     

Microstructure and optical properties of Al2O3 prepared by oblique deposition using microsphere shell templates

We fabricated an orderly inclined Al2O3 column array using a hollow microsphere template. The microstructure and optical properties were investigated with scanning electron micrography and a UV/VIS spectrometer, respectively. Microsphere shell templates were formed using atomic layer deposition to prevent the melting of polystyrene microspheres during the following high-temperature deposition process. An inclined Al2O3 column array with a 30° tilt angle was grown by oblique deposition on a substrate with a 75.5° tilt angle with respect to the substrate normal. Birefringence and photonic crystalline behavior can be observed in the orderly inclined column array. The difference in the refractive indices between the p and s polarizations of the orderly inclined Al2O3 column array was about 0.1. The photonic properties of the crystal were enhanced compared to those of substrates without patterns.