Thin Processes Research Articles

Evolution and influence of GaN/AlN heterointerface during the thinning process of GaN film

The structure of GaN/AlN heterointerface is commonly used in the high electron mobility transistors. To investigate the evolution and influence of GaN/AlN heterointerface during thinning, the grinding process of GaN films is simulated by molecular dynamics. The differences in the grinding process between GaN film with different thickness and pure GaN are compared. It is found that dislocation and phase transformation are the main defects at the GaN/AlN heterointerface, which will cause the stress concentration in the workpiece. The thinning process will lead to the evolution of the heterointerface and reduce the dislocation at the interface. Compared with the thinning of pure GaN, the heterointerface will promote the transformation from hexagonal wurtzite structure to cubic zinc-blende structure. In addition, there will be more chip atoms in the thinning process, because the heterointerface can hinder heat conduction and result in the higher temperature of GaN film.

Efficient Parallel Thinning of 3d Objects on the Body-centered Cubic Lattice

We consider thinning methods to extract one dimensional skeletons from discrete objects defined on the body-centered cubic (bcc) lattice. In Strand (2004), a condition has been given that guarantees the preservation of the object’s topology in such a thinning process. In this paper, we present stronger conditions that even allow the topological invariant point removal in a parallelized process. These conditions for p -simplicity can be efficiently evaluated which leads to a very fast thinning process. We show that p -simplicity is a new concept that cannot be obtained by adapting the checking plane conditions of Tsao and Fu to the bcc lattice. Furthermore, we introduce distance information and an optional pruning mechanism into the thinning process to improve the quality of the resulting skeletons. The presented results show that our method generates high quality skeletons that reproduce the symmetries of the models even under the condition of added noise and contain only very few spurious branches. The presented running times demonstrate the linear run-time behavior of our algorithm and the speedup that is achieved by the parallelization. • Curve-like skeletons of closed 3D objects are used for many different purposes in computer graphics. • Thinning is a method to extract the skeleton which requires the object to be discretized on a lattice. • Only for thinning on the cubic grid parallel algorithms are available. • We present the first parallel thinning algorithm on the bcc lattice. • Our method generates high quality skeletons that contain only very few spurious branches. • The skeletons reproduce the symmetries of the models even under the condition of added noise.

NEW VAPOR DEPOSITED DIELECTRIC POLYMER THIN FILMS FOR ELECTRONIC APPLICATIONS

Dielectric materials are of great interest in a vast amount of applications ranging from cable insulation to advanced electronic devices. The emerging trend of device miniaturization is creating an increased demand for dielectric thin films that can be produced precisely on the nanometer scale. In addition, special mechanical properties are often required, for example in the field of flexible organic electronics. Polymers are first-choice materials for this purpose. However, it is extremely difficult to produce precise nanoscale thin films, which have a low defect density and are free of e.g. residual solvent, by wet chemistry approaches. Initiated chemical vapor deposition (iCVD) is a solvent-free polymer thin film deposition process which can be used to produce high quality dielectric thin films with nanoscale control and circumvents thus these problems. This work demonstrates the versatility of the iCVD process in the field of electrical applications by some new application examples of iCVD. By adding e.g. a hydrophobic organosiloxane thin film on columnar zinc oxide (ZnO:Fe) gas sensing structures there was a change in the selectivity from ethanol to hydrogen, as well as improved performance at high humidity level. The modified sensors can thus be used in humid ambient, especially for breathing tests, which can lead to the diagnosis of some diseases by cutting edge non-invasive approaches.

Low pressure assisted thin film growth for high performance perovskite solar cells

• Simple thin film manufacturing process. • Improved the perovskite film quality. • Enhanced PCE and environment stability. Perovskite solar cells (PSCs) have been the most promising candidate for next generation commercial solar cells after silicon cells. However, the original perovskite films always present defects showing pinholes and uneven particles causing low performance and stability during operation. Here, we prepared high quality and outstanding performance perovskite films through low pressure assisted (LPA, −1 bar) thin film growth strategy to control morphology and crystallinity form precursor perovskite solution. Consequently, the PSCs (target) showed a maximum power conversion efficiency (PCE) of 20.33% based on LPA growth perovskite films, while the PCE for normal annealing devices (control) was only 19.47%. The target devices also showed superior stability at a humidity range of 20%-30% compared with control devices. After 1000 h, 66.50% initial PCE was remained for target devices (20.33% to 13.52%), only 45.45% for control devices (19.47% to 8.85%).

Pinch-off dynamics of double-emulsion droplets with/without the influence of interfacial coupling effect

Pinch-off dynamics of double-emulsion droplets is experimentally studied. Pure liquid systems with different combinations of three-phase viscosities are considered to particularly reveal the thinning mechanisms and their variation characteristics when the interfacial coupling effect exists. The whole breakup process is analyzed at first, and the pinch-off stage governed by the interfacial tension is confirmed. The scaling law of the minimum neck width is constructed to make quantitative comparisons with the conventional theories obtained from single emulsions. The influence of the coupling effect on the thinning dynamics is discussed by sequentially varying the viscosity of one single phase of the liquid system. With the coupling effect, it is found that the rapid collapsing occurs in advance due to the superposition of the Laplace pressure differences at the minimum neck width. The thinning rate of the outer droplet follows that of the inner droplet until the breakup of the inner droplet, after which the thinning process of the outer droplet quickly coincides with the uncoupled case as the disturbances damp out by relatively high viscosity. On the contrary, the subsequent thinning dynamics would be changed when the low-viscosity liquid is used.

(Invited, Digital Presentation) Ion Implantation for Amorphous-InGaZnO Sheet Resistance Control Technique

As a next-generation electronics material, amorphous-InGaZnO (a-IGZO) film devices were investigated. In order to further utilize a-IGZO films, we carried out conventional ion of boron (B+) or neon (Ne+) implantations in a-IGZO thin films on glass and analyzed the implanted a-IGZO via Hall measurement with wet etching. In addition, a-IGZO thin film transistor processes with the implantation were carried out. As a result, we find that both ions drastically decrease a-IGZO sheet resistances. However, we observed oxygen vacancy area increase in the case of Ne+ implanted a-IGZO in 300 oC post annealing, which indicates Ne diffuses in a-IGZO film. On the other hand, B diffusion was not observed by depth profile comparison between the implanted samples with and without annealing. Furthermore, we extract key device parameters, such as effective channel length and ON/OFF current ratio, which can be applied to a-IGZO device processing.

Transzonal projections: Essential structures mediating intercellular communication in the mammalian ovarian follicle.

The development of germ cells relies on contact and communication with neighboring somatic cells that provide metabolic support and regulatory signals. In females, contact is achieved through thin cytoplasmic processes that project from follicle cells surrounding the oocyte, extend through an extracellular matrix (ECM) that lies between them, and reach its surface. In mammals, the ECM is termed the zona pellucida and the follicular cell processes are termed transzonal projections (TZPs). TZPs become detectable when the zona pellucida is laid down during early folliculogenesis and subsequently increase in number as oocyte growth progresses. They then rapidly disappear at the time of ovulation, permanently breaking germ-soma contact. Here we review the life cycle and functions of the TZPs. We begin with an overview of the morphology and cytoskeletal structure of TZPs, in the context of actin- and tubulin-based cytoplasmic processes in other cell types. Next, we review the roles played by TZPs in mediating progression through successive stages of oocyte development. We then discuss two mechanisms that may generate TZPs-stretching at pre-existing points of granulosa cell-oocyte contact and elaboration of new processes that push through the zona pellucida-as well as gene products implicated in their formation or function. Finally, we describe the signaling pathways that cause TZPs to be retracted in response to signals that also trigger meiotic maturation and ovulation of the oocyte. The principles and mechanisms that govern TZP behavior may be relevant to understanding communication between physically separated cells in other physiological contexts.

W-대역 고출력 증폭기 응용을 위한 E-평면 신호 전이 구조 및 저항성 격막을 이용한 도파관 전력 결합기

In this study, a wideband, low-loss waveguide power combiner is designed and manufactured using a waveguide-to-microstrip signal transition feed and resistive septum, which can be applied to waveguides in the W-band. The waveguide power combiner has a T-junction structure and is implemented by locating the transition feed at a length of λ/4, where the E-field is maximized, and combining the resistive septum manufactured by the NiCr thin film process. The performance is verified using a passive integrated circuit IC in the form of a microstrip line matched with 50 Ω to the manufactured combiner, and the combined characteristics according to the presence or absence of a resistive septum are confirmed by mounting a power amplifier PA. The isolation of the combiner with the resistive septum is −15 dB compared with the 9 dB without a resistive septum, which improves the simulation results. The power combining module manufactured using the passive IC exhibits a low insertion loss of approximately 0.75 dB (@ 78 GHz) after the output stage with the transition structure and including the resistive septum structure. As a result of constructing a power combining module with a waveguide structure using an MMIC with an amplification gain of approximately 20 dB and an output performance of 26 dBm, in the absence of a resistive septum, a low-power-combining characteristic of approximately 8 dB gain and 14 dBm is achieved. When a resistive septum is applied, it exhibits a stable amplification gain of approximately 18 dB and output performance of 28.4 dBm (2.4 dB combined gain).

Flexible Ferroelectric Devices: Status and Applications

AbstractFlexible electronic devices have been extensively studied for their advantages of distinguished portability, conformal contact characteristics, and human‐friendly interfaces compared with conventional bulk Si technology. Flexible electronics can be attached to various surfaces like skin and internal organs for human–machine interaction, which has made significant advances in electronics, medicine, neuromorphic computing, etc. Owing to the innovation and maturation of the thin film preparation process, which have promoted the successful preparation of high‐quality flexible ferroelectric films. Herein, the preparation of flexible ferroelectric devices and the progress of their applications in recent years are reviewed. Prevailing methods for preparing flexible ferroelectric films including the van der Waals heteroepitaxy on flexible substrate, delamination of the ferroelectric films on rigid substrate by chemical etching techniques, and direct use of novel 2D ferroelectric materials etc. are summarized. The research progress of flexible ferroelectric devices applied to memories, sensors, photovoltaic devices, and energy harvesters are also be discussed in detail. Moreover, the potential applications of flexible ferroelectric devices in the field of neuromorphic computing are studied, a new trend which contributes to the further development of brain‐like chip systems. Finally, the challenges and prospects of flexible ferroelectric devices in the future advanced electronics are briefly proposed.

Thick Film Ultrasonic Micromotor Based on Chemical Mechanical Thinning and Polishing Process

In this letter, a millimeter scale thick film rotating traveling wave ultrasonic motor based on chemical mechanical thinning and polishing process was proposed. The 30 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> thick piezoelectric functional layer is fabricated to realize good compactness and high piezoelectric properties. The thickness and diameter of the stator are about 240 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> and 4 mm, respectively. The vibration mode of the motor is B02 mode under the resonant frequency of 26.2 kHz. The motor can achieve stable bidirectional rotation under the excitation of four sinusoidal voltages. Moreover, when the excitation voltage is 50 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{V}_{\text {pp}}$ </tex-math></inline-formula> , the maximum speed can reach 766 rpm under the preload force of 686 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{N}$ </tex-math></inline-formula> .

Novel Active-Matrix Micro-LED Display With External Compensation Featuring Fingerprint Recognition

This letter proposes a novel active-matrix (AM) micro light-emitting diode (micro-LED) display architecture featuring fingerprint detection. A new pixel circuit comprising four transistors and one capacitor (4T1C) is proposed to compensate for threshold voltages externally. The proposed AM micro-LED display does not need any additional light sources and sensors because an LED itself can be used for photosensors. The proposed 4T1C pixel circuit can isolate the effects of LED photocurrents caused by ambient lights and large LED capacitance from detecting the threshold voltage via external circuits. The proposed AM pixel circuit with oxide thin film transistors was fabricated using oxide thin film transistor process. The charges caused by the LED photocurrents were accumulated for 16.7 ms. The final voltages measured after 16.7 ms were −5.02 V and −1.53 V under irradiance of 0.05 W/m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and 1.54 W/m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , respectively. It is verified that the proposed micro-LED pixel circuit could distinguish incident lights reflected from ridges and valleys of a fingerprint.

Behavior and Functional Roles of CD34+ Mesenchymal Cells in Mammalian Testes.

Mammalian testes consist of seminiferous tubules within which Sertoli cells line up at the periphery and nurse germ cells, and of interstitia that harbor various cells such as peritubular myoid cells (PMCs), Leydig cells (LCs), vascular endothelial cells, immune cells such as macrophages, and mesenchymal (stromal) cells. Morphological studies have recently reported the presence of telocytes with telopodes in the interstitium of adult mouse, rat, and human testes. CD34+PDGFRα+ telocytes with long and moniliform telopodes form reticular networks with various cell types such as LCs, PMCs, and vessels, indicating their potential functions in cell–cell communications and tissue homeostasis. Functional studies have recently been performed on testicular interstitial cells and CD34+ cells, using 3D re-aggregate cultures of dissociated testicular cells, and cell cultures. Direct observation of CD34+ cells and adult LCs (ALCs) revealed that CD34+ cells extend thin cytoplasmic processes (telopodes), move toward the LC–CD34+ cell-re-aggregates, and finally enter into the re-aggregates, indicating the chemotactic behavior of CD34+ telocytes toward ALCs. In mammalian testes, important roles of mesenchymal interstitial cells as stem/progenitors in the differentiation and regeneration of LCs have been reported. Here, reports on testicular telocytes so far obtained are reviewed, and future perspectives on the studies of testicular telocytes are noted.

Coherent Forecasting for a Mixed Integer-Valued Time Series Model

In commerce, economics, engineering and the sciences, quantitative methods based on statistical models for forecasting are very useful tools for prediction and decision. There is an abundance of papers on forecasting for continuous-time series but relatively fewer papers for time series of counts which require special consideration due to the integer nature of the data. A popular method for modelling is the method of mixtures which is known for its flexibility and thus improved prediction capability. This paper studies the coherent forecasting for a flexible stationary mixture of Pegram and thinning (MPT) process, and develops the likelihood-based asymptotic distribution. Score functions and the Fisher information matrix are presented. Numerical studies are used to assess the performance of the forecasting methods. Also, a comparison is made with existing discrete-valued time series models. Finally, the practical application is illustrated with two sets of real data. It is shown that the mixture model provides good forecasting performance.

Effect of ZrO2 on sintering behavior and properties of h-BN/ZrO2 composites by spark plasma sintering

The h-BN/ZrO2 composites with different 3Y–ZrO2 content were prepared by spark plasma sintering at 1800 °C. The sintering behavior, bulk density, apparent porosity, thermal conductivity, thermal expansion coefficient, bending strength, thermal shock resistance, microstructure and phase were analyzed. The optimum specimens were used to test the resistance to corrosion of molten steel for 10, 20, 40, 80 min respectively. The results indicated that ZrO2 could facilitate the sintering process of h-BN matrix under the action of spark plasma. Especially, for the composites with 30 wt% 3Y–ZrO2, the porosity could decrease to 1.1% and the flexural strength could exceed 150 MPa. The microstructure showed the h-BN grains and 3Y–ZrO2 grains are closely combined. The XRD patterns indicated that the t-ZrO2 diffraction peak gradually enhanced with the increase of density. With the increase of erosion time, the erosion rate increased significantly. After the surface of the specimen is eroded, the erosion resistance of the matrix would decrease significantly. This h-BN/ZrO2 could be as side-dam used in the thin strip continuous casting process.

Formulation, evaluation, and in vitro drug diffusion of niosomal gel of selected drug

Aim: To minimise toxicity and alter pharmacokinetic and bioavailability, niosomes are becoming more significant in medication delivery. Rheumatoid arthritis, juvenile rheumatoid arthritis, and degenerative joint disease may benefit from this new non-steroidal anti-inflammatory, antipyretic, and analgesic drug. Materials and Methods: Non-ionic surfactants (Span 40, 60, and Tween 60) and cholesterol were used in various ratios to create tolmetin sodium niosomes in a thin film hydration process (CHO). Evaluations of the formulations were conducted in terms of size, shape, encapsulation efficiency, and in vitro drug release. Results: In vitro drug release ranged from 94.87±0.45 to 93.19±0.45 percent in 24 hours for niosomes that looked spherical in entrapment efficiency. Incorporating Tolmetin sodium niosomes with Span 60 and CHO in the ratio of 1:2.1 into Carbopol gel was shown to be promising. Tolmetin drug noisome has a drug content and pH of 99.19±1.20 and 7.0±0.06, respectively. Conclusion: An improved bioavailability gel formulation with Tolmetin sodium in niosomal form demonstrated longer effect than gel formulations containing Tolmetin in non-niosomal form.

Solvent-Induced Crystallization Method for High-Performance and Long-Term Stability Flexible Perovskite Photodetectors

Herein, we report a novel solvent-induced fabrication method to synthesize a perovskite thin film on flexible substrates. The high-quality CH3NH3PbI3 (MAPbI3) thin film is successfully fabricated, which is applied to prepare the stable flexible photodetector (PD). Compared with the reported results, this method achieved a low-temperature and low-cost perovskite thin film fabrication process on a flexible substrate. The constructed MAPbI3 layer possesses the advantages of being highly crystalline, uniform, and compact in a large area. The flexible PD based on the as-prepared perovskite thin film exhibits excellent performance and long-term stability. The EQE and R of the flexible PDs reached 8 × 102% and 3.6 A/W, respectively. At the same time, the flexible PDs still showed superior stability and high performance after 15 days of continuous working. The presented high-quality perovskite thin-film fabrication method and high-performance flexible perovskite PDs are expected for application in the development of novel optoelectronic devices.

Continuous production of cellulose microbeads by rotary jet atomization

The replacement of plastic microbeads with biodegradable alternatives is essential due to the environmental persistence of plastics and their accumulation within the human food chain. HypothesisCellulose microbeads could be such alternative, but their production is hindered by the high viscosity of cellulose solutions. It is expected that this viscosity can be harnessed to induce filament thinning of jets of cellulose solutions to create droplets with diameters within the micrometre range, which can then be converted to solid cellulose microbeads via phase inversion. ExperimentsA 3D printed rotating multi-nozzle system was used to generate jets of cellulose dissolved in solutions of [EMIm][OAc] and DMSO. The jets were subject to Rayleigh breakup to generate droplets which were captured in an ethanol anti-solvent bath, initiating phase-inversion, and resulting in regeneration of the cellulose into beads. FindingsControl of both process (e.g. nozzle dimensions) and operational (e.g. rotational speed and pressure) parameters has allowed suppression of both satellite droplets generation and secondary droplet break-up, and tuning of the filament thinning process. This resulted in the continuous fabrication of cellulose microbeads in the size range 40–500 μm with narrow size distributions. This method can produce beads in size ranges not attainable by existing technologies.

Iterative method for obtaining nonuniform grinding-induced residual stress distribution of silicon wafers based on global deformation

Grinding as the main thinning process for silicon wafers is widely used in chip manufacturing. The residual stress distribution is desired to be known to optimize the grinding process. In this paper, an iterative method for obtaining the nonuniform residual stress of ground silicon wafers was proposed. The deformation of ground silicon wafers was divided into two parts in which one part was large spherical deformation and the other was a small out-of-sphere deformation. The spherical deformation which was in the nonlinear range corresponded to an average stress which was obtained using the bisection method. The small out-of-sphere deformation corresponded to the stress variation which was obtained using the regularization method with continuity constraints. An iterative successive approximation process was conducted to address the nonlinear problem which was transformed into a local linear problem. The residual stress distribution of a ground silicon wafer was obtained successfully using the proposed method. Although the overall shape of the wafer deformation was approximately spherical, the residual stress value varied a lot with the crystal orientation of the silicon wafer. The stress values in the <110> orientations were much larger than those in the <100> orientations. The method could be used to evaluate the grinding process independently of the dimension sizes of ground silicon wafers. The proposed method in this paper is non-destructive and could be used to track the residual stress changes in the grinding process and the process parameters could be optimized accordingly.

Automatic flower cluster estimation in apple orchards using aerial and ground based point clouds

Chemical and mechanical thinning processes have long been used in stone and pome fruit production. During the thinning of apple flowers, growers use chemicals to regulate the tree load. Hand thinning is applied after the June drop to prune trees with excess crop load. The process of thinning can be unpredictable especially in biennial bearing cultivars. Thus, incentives to optimise chemical usage and to reduce expensive manual labour is ever increasing. Ground based machine vision systems have grown in popularity in orchard management due to the level of detail as well as plant coverage they can inspect with. Additionally, unmanned aerial vehicles (UAV) -based remote sensing technology is becoming a popular non-invasive quality inspection solution. This work proposes a framework for combining UAV and ground based RGB image data to detect flowering intensity in a Dutch Elstar apple orchard. The framework, based on point cloud reconstruction, presents automatic point cloud handling techniques as well as automated unsupervised flowering intensity estimation methods. Two linear regression models based on unsupervised machine learning methods were trained and validated from the framework that estimate flowering intensity in the orchard with both models having R 2 > 0.65, RRMSE < 20% and p-stat < 0.005 for the correlation between the image derived flower index and the flower cluster number counted in field. The proposed methods provide a novel strategy for guiding flower thinning using simple RGB images and location data only. Moreover, the proposed methods also reveal the flexibility of intra-tree inspection by checking its sub-volumes. • Automatic flower cluster estimation at the tree level with a R 2 = 0.7, RMSE < 20. • Ground and aerial point clouds have better performance when combined. • Novel strategy developed for guiding flower thinning in orchard management. • Dataset with aerial and ground images, and field sampling data released.

Technological measures to improve the environmental friendliness of alcohol industry enterprises

The article concerns technological measures to improve the environmental friendliness of food industry enterprises: in particular, aspects of processing waste from the alcohol industry with further use in agriculture (in animal feed). It is important to use methods to optimize the feeding of farm animals, allowing one to involve feed resources that do not have a harmful effect on health and productivity, while significantly reducing the consumption of grain components. This resource is dry distillery grains, which is a waste product of distillery production. Technologies of distillery bard processing include its evaporation with further drying. The main waste at the ethanol plant is whole stillage. It is centrifuged to separate thin stillage from wet grains. Thin stillage contains 5-10% of solids. For reducing energy consumption during the concentration process, it is possible to use a direct contact evaporator (bubbling evaporator). In this article, the bubbling evaporator design was developed. To justify the size of the evaporator, the temperature difference profile along the column length was determined. It is less than 1 and remains constant, which determines the high efficiency of heat transfer. The most effective parameters of the evaporation process according to moisture removal are a gas flow rate of 1.3–1.5 m3/h, air temperature of 400±15. Work results can be used in the design of scalable systems for thin stillage processing and applicable in medium-sized ethanol plants.