RF-MEMS load sensors with enhanced Q-factor and sensitivity in a suspended architecture

In this paper, we present and demonstrate RF-MEMS load sensors designed and fabricated in a suspended architecture that increases their quality-factor (Q-factor), accompanied with an increased resonance frequency shift under load. The suspended architecture is obtained by removing silicon under the sensor. We compare two sensors that consist of 195 μm × 195 μm resonators, where all of the resonator features are of equal dimensions, but one’s substrate is partially removed (suspended architecture) and the other’s is not (planar architecture). The single suspended device has a resonance of 15.18 GHz with 102.06 Q-factor whereas the single planar device has the resonance at 15.01 GHz and an associated Q-factor of 93.81. For the single planar device, we measured a resonance frequency shift of 430 MHz with 3920 N of applied load, while we achieved a 780 MHz frequency shift in the single suspended device. In the planar triplet configuration (with three devices placed side by side on the same chip, with the two outmost ones serving as the receiver and the transmitter), we observed a 220 MHz frequency shift with 3920 N of applied load while we obtained a 340 MHz frequency shift in the suspended triplet device with 3920 N load applied. Thus, the single planar device exhibited a sensitivity level of 0.1097 MHz/N while the single suspended device led to an improved sensitivity of 0.1990 MHz/N. Similarly, with the planar triplet device having a sensitivity of 0.0561 MHz/N, the suspended triplet device yielded an enhanced sensitivity of 0.0867 MHz/N.     

The effect of wollastonite incorporation on the linear firing shrinkage and flexural strength of dental aluminous core ceramics: A preliminary study

The aim of this study is to evaluate the effect of wollastonite (CaSiO3) material on the linear firing shrinkage and flexural strength of dental aluminous core porcelain. Twenty five specimens were prepared in a manner that each five of them contained 0%, 2%, 3%, 4%, and 5% wollastonite by weight. The linear firing shrinkage values were determined according to the formula given in the standard ANSI/ADA (American National Standards Institute/American Dental Association) 69 and the flexural strength of the specimens was evaluated using 3-point bending test. The results of this study showed that addition of wollastonite reduced the linear firing shrinkage and increased the flexural strength of dental aluminous core porcelain. The highest reduction (approx. 20%) in the linear firing shrinkage was obtained by the addition of 5% wollastonite. Kruskal–Wallis test found a statistically significant difference among the mean linear firing shrinkage values of the porcelain groups at the 95% confidence level (p < 0.05). Mann Whitney U statistical test was performed to demonstrate which porcelain groups show statistically significant difference. In spite of achieving 30% increase in the flexural strength by the addition of 2% wollastonite, no statistically significant difference was found among the mean flexural strength values of the porcelain groups (p > 0.05).     

Liquid–Liquid Diffusion‐Assisted Crystallization: A Fast and Versatile Approach Toward High Quality Mixed Quantum Dot‐Salt Crystals

Here, a new, fast, and versatile method for the incorporation of colloidal quantum dots (QDs) into ionic matrices enabled by liquid–liquid diffusion is demonstrated. QDs bear a huge potential for numerous applications thanks to their unique chemical and physical properties. However, stability and processability are essential for their successful use in these applications. Incorporating QDs into a tight and chemically robust ionic matrix is one possible approach to increase both their stability and processability. With the proposed liquid–liquid diffusion‐assisted crystallization (LLDC), substantially accelerated ionic crystallization of the QDs is shown, reducing the crystallization time needed by one order of magnitude. This fast process allows to incorporate even the less stable colloids including initially oil‐based ligand‐exchanged QDs into salt matrices. Furthermore, in a modified two‐step approach, the seed‐mediated LLDC provides the ability to incorporate oil‐based QDs directly into ionic matrices without a prior phase transfer. Finally, making use of their processability, a proof‐of‐concept white light emitting diode with LLDC‐based mixed QD‐salt films as an excellent color‐conversion layer is demonstrated. These findings suggest that the LLDC offers a robust, adaptable, and rapid technique for obtaining high quality QD‐salts.     

穆格莱德盆地A区块构造特征对油气分布的影响

由于穆格莱德盆地A区块构造位置特殊、断裂特征复杂、构造样式多,现有的研究成果不能满足A区块勘探、开发需求。为此,对研究区重新划分构造分区、深入研究断裂活动期次、对比不同构造单元之间活动差异性、恢复构造演化史,并分析构造演化与油气成藏的关系。结果表明：①A区块构造演化过程经历前裂谷期、同裂谷期和后裂谷期,同裂谷期又进一步划分为三个构造阶段,即早白垩世—晚白垩世、晚白垩世—古新世、始新世—上新世,分别控制烃源岩、构造圈闭、油气分布。②A区块从东向西可以划分为继承稳定型和持续活动型两种构造分区。前者以凯康东部斜坡和凯康西部斜坡为典型,在演化阶段构造活动强度具有“强—强—弱”的特征;后者以凯康槽为典型,在演化阶段构造活动强度具有“强—强—最强”的特征。③A区块存在“断裂活动减弱型深层”和“断裂活动持续型的晚期调整多层系”两种油气成藏模式。前者多见于凯康东部斜坡和凯康西部斜坡,后者常见于凯康槽。上述认识对类似地质条件盆地的油气勘探具有参考价值。     

Conducting banding analysis with trained networks of sigmoid units

Berkeley et al. (1995, Connection Science, 7: 167–186) introduced a novel technique for analysing the hidden units of connectionist networks that had been trained using the backpropagation learning procedure. The literature concerning banding analysis is equivocal with respect to the kinds of processing units this technique can be used on. In this paper, it will be shown that, contrary to the claims in some published sources, banding analysis can be conducted on networks that use standard processing units that have a sigmoid activation function. The analytic process is then illustrated and the potential benefits of this kind of technique are discussed.     

Crystallization kinetics of basalt glass

The crystallization behaviour of basalt glass at elevated temperatures was studied using glass samples prepared by melting the natural basalt rock from the Thrace region of Türkiye. DTA and XRD analysis revealed the crystallization of augite [(Ca Fe Mg) SiO₃ at 800 °C. The kinetics of crystallization of augite were studied by applying the DTA measurements carried out at different heating rates and the activation energies of crystallization and viscous flow were measured as 238 kJ mol⁻¹ and 413 kJ mol⁻¹, respectively. The resultant basalt glass-ceramic revealed very fine and homogeneous microstructure.     

Psychiatric problems within the satellite-extended families of Turkey

The many Turkish villagers who now migrate to large Turkish cities or enter the European labor force try to create models of the extended families they leave behind. Their satellite families necessarily drift away from tradition, however, in the direction of greater independence. This process often triggers psychiatric symptom formation.     

Room-Temperature Mid-, and Far-Infrared Absorption and Electrical Properties of Intercalated GaSe and TlInS<Subscript>2</Subscript> Crystals

We report room-temperature measurements of the mid- and far-IR absorption throughout the 400 – 4000 cm^?1 and 10 – 700 cm^?1 spectral ranges and the resistivity of layered p-GaSe and p-TlInS2 intercalated with Li⁺. Intercalation was performed by immersing Bridgman grown crystals in 0.5 M solutions of LiCl in distilled water at ambient conditions. The crystal structure and the stoichiometry of the grown crystals were determined by X-ray diffraction and XRF methods. It is shown that intercalation does not change the frequency of the IR-, and Raman active low-frequency“rigid layer” mode (GaSe), the space symmetry group or the lattice parameters of the crystals. It was found that for both crystals, the resistivity versus time dependencies are nearly the same. Three ranges in the resistivity-intercalation time dependencies were explained qualitatively. The resistivity increase due to intercalation was explained by assuming that the intercalated lithium ions act as ionized donors and compensate the host p-type crystal. The highest degree of compensation for GaSe and TlInS₂ crystals was achieved after intercalation during 12 and 10 days, respectively.