Utilizing inkjet printing to fabricate electrical interconnections in a system-in-package

The printed interconnections for encapsulated electronic packages using nanoparticle metal inks and polymer dielectrics have been demonstrated. The printing has utilized a digital printing method, inkjet printing. The printing process has been adopted rather well, but process yield improvement required more attention to the control of individual manufacturing stages and error sources. The sources for possible errors can be roughly divided into separate groups: the substrate-ink interaction and treatment procedure related, ink jetting related, and moving stage related. In this paper, the individual stages were taken under consideration. The process performance was studied using statistical methods. The affecting factors were classified, and designed experiments were carried out to determine the most significant factors and to create a model to describe the behavior. According to the models, optimized process parameters were achieved, and implemented in practice.     

Record amorphous silicon single‐junction photovoltaic module with 9.1% stabilized conversion efficiency on 1.43 m2

Providing two‐thirds of the total stabilized power of thin‐film tandem MICROMORPH^TM technology, the amorphous junction remains a key element in the quest for higher efficiencies. This paper reports and summarizes a considerable work to achieve a record large‐area amorphous silicon single‐junction photovoltaic module. New hardware has been developed and known process steps have been accurately tuned and combined with new features of cell design. Effort was focused on the deposition of high‐quality and low‐defect a‐Si:H layers that has promoted an improved device stability and resistance against light induced degradation. Efficient light management has been used, and module design has been revised. The word‐record performance reported in this paper for a large‐area (1.43 m²) stabilized module conversion efficiency (total area) was measured and certified by Swiss PV Module Test Center to be 9.1%. Copyright © 2016 John Wiley & Sons, Ltd.     

A Novel Underlay Cognitive Radio Based on Direct Sequence Complementary Coded CDMA

In this study, we propose a spectrum sharing scheme where secondary-users (SUs) can co-exist at the same frequency band with the primary-users simultaneously. Both primary (PN) and secondary networks (SN) are considered as CDMA based networks with the same set of orthogonal complementary codes. An orthogonal complementary code set possesses both ideal auto-correlation function (ACF) of any code and ideal cross-correlation function for any two codes in the same set. In the proposed scheme, a delay is applied to the transmission of the SN which exploits ideal ACF properties of complementary codes and will not interfere the transmission of the primary user. Numerical results show that the proposed scheme enables SUs to efficiently utilize the PN’s licensed spectrum without any harmful interference.     

Weak imposition of boundary conditions for the Navier–Stokes equations by a penalty method

We prove convergence of the finite element method for the Navier–Stokes equations in which the no‐slip condition and no‐penetration condition on the flow boundary are imposed via a penalty method. This approach has been previously studied for the Stokes problem by Liakos (Weak imposition of boundary conditions in the Stokes problem. Ph.D. Thesis, University of Pittsburgh, 1999). Since, in most realistic applications, inertial effects dominate, it is crucial to extend the validity of the method to the nonlinear Navier–Stokes case. This report includes the analysis of this extension, as well as numerical results validating their analytical counterparts. Specifically, we show that optimal order of convergence can be achieved if the computational boundary follows the real flow boundary exactly. Copyright © 2008 John Wiley & Sons, Ltd.     

线性LED驱动器IC为何必然替代偏压电阻器

利用简单的电阻器限制LED串中的电流看似最为经济和简便，那么为何还要费尽心思地使用线性驱动器IC？     

Permutation Based Design of Orthogonal Block Transforms and Filter Banks

In this work, a new efficient design techniquefor orthogonal block transforms, lapped orthogonal transformsand 4-channel perfect reconstruction subband filter banks isdeveloped. The technique consists of permutation and sign changeoperations on a reference vector. This approach can be thoughtof as a generalization of the Hadamard transform in the sensethat the reference vector h ₀ (which will be a prototype low-pass filteralso forming one of the basis functions of the transform) willin general have components that are not identically 1's. Thedesign technique, a constructive method based on Hadamard arrays,provides a convenient means to explore new transforms. The meritof our method is that the number of unknowns and equality constraintsare both reduced significantly which render the design proceduremuch more feasible while guaranteeing at the same time linearphase.     

A microchip sensor for calcium determination

A newly designed glass-PDMS microchip-based sensor for use in the determination of Ca²⁺ ions has been developed, utilizing reflectance measurements from arsenazo III (1,8-dihydroxynaphthalene-3,6-disulfonic acid-2,7-bis[(azo-2)-phenyl arsenic acid]) immobilized on the surface of polymer beads. The beads, produced from cross-linked poly(p-chloromethylstyrene) (PCMS), were covalently modified with polyethylenimine (PEI) to which the Arsenazo III could be adsorbed. The maximum amount of Arsenazo III which could be immobilized onto the PEI-attached PCMS beads was found to be 373.71 mg g⁻¹ polymer at pH 1. Once fabricated, the beads were utilized at the detection point of the microfluidic sensor device with a fiber optic assembly for reflectance measurements. Samples were mobilized past the detection point in the sensor where they interact with the immobilized dye. The sensor could be regenerated and re-used by rinsing with HCl solution. The pH, voltage, linear range, and the effect of interfering ions were evaluated for Ca²⁺ determination using this microchip sensor. At the optimum potential, 0.8 kV, and pH 9.0, the linear range of the microchip sensor was 3.57 × 10⁻⁵ – 5.71 × 10⁻⁴ M Ca²⁺, with a limit of detection (LOD) of 2.68 × 10⁻⁵ M. The microchip biosensor was then applied for clinical analysis of calcium ions in serum with good results. Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users.     

On inverse problem for singular Sturm-Liouville operator from two spectra

We study an inverse problem with two given spectra for a second-order differential operator with singularity of the type (here, l is a positive integer or zero) at zero point. It is well known that two spectra {λ _n } and {λ _n } uniquely determine the potential function q(r) in the singular Sturm-Liouville equation defined on the interval (0, π]. One of the aims of the paper is to prove the generalized degeneracy of the kernel K(r, s). In particular, we obtain a new proof of the Hochstadt theorem concerning the structure of the difference . Published in Ukrains’kyi Matematychnyi Zhurnal, Vol. 58, No. 1, pp. 132–138, January, 2006.     

Temperature dependence of the optical band gap and electrical conductivity of sol-gel derived undoped and Li-doped ZnO films

Undoped and lithium (Li)-doped ZnO films were prepared by sol-gel method using spin coating technique. The effects of Li content on the crystallinity and morphological properties of ZnO films were assessed by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). XRD patterns of the films showed the hexagonal wurtzite type polycrystalline structure and that the incorporation of lithium leads to substantial changes in the structural characteristics of ZnO films. The SEM and AFM measurements showed that the surface morphology of the films was affected from the lithium incorporation. The wrinkle network was observed on the surface from both SEM and AFM results for undoped ZnO. The wrinkle structure disappeared with increasing Li content. The absorption spectra of the ZnO and 5% Li-doped ZnO (LZO5) films were carried out between 140 and 400 K temperatures. The optical band gap of ZnO and LZO5 films (calculated at various temperatures) showed a linear dependence on the temperature. The absolute zero value optical band gap and the rate of change of the band gap with temperature of the ZnO and LZO5 films were found to be 3.339 and 3.322 eV, and 2.95 × 10⁻⁴ and 1.60 × 10⁻⁴ eV/K, respectively. The transport mechanisms in the ZnO and LZO5 films have been investigated by analyzing of the temperature (80-300 K) dependence of the conductivity. The activation energies of the ZnO film increased with Li content.     

A density functional theory study of ethylene adsorption on Ni10(1 1 1), Ni13(1 0 0) and Ni10(1 1 0) surface cluster models and Ni13 nanocluster

Ethylene adsorption was studied by use of DFT/B3LYP with basis set 6-31G(d,p) in Gaussian’03 software. It was found that ethylene has adsorbed molecularly on all clusters with π adsorption mode. Relative energy values were calculated to be −50.86 kcal/mol, −20.48 kcal/mol, −32.44 kcal/mol and −39.27 kcal/mol for Ni₁₃ nanocluster, Ni₁₀(1 1 1), Ni₁₃(1 0 0) and Ni₁₀(1 1 0) surface cluster models, respectively. Ethylene adsorption energy is inversely proportional to Ni coordination number when Ni₁₀(1 1 1), Ni₁₃(1 0 0) and Ni₁₀(1 1 0) cluster models and Ni₁₃ nanocluster are compared with each other.