Search

In response to the increased mobile data traffic, there is a growing need for more low-loss RF band filters with steep frequency characteristics, and high-quality ( $Q$ )-factor and low-temperature coefficient of frequency (TCF) resonators are required to achieve this. We previously reported that for a surface acoustic wave (SAW) resonator on a three-layer structure, which is composed of a thin LiTaO3 (LT) plate whose orientation is 50° rotated YX propagation, SiO2 layer, and AlN layer on a Si substrate, a Q-factor several times higher than that of an SAW resonator on a standard 42° rotated YX propagation LiTaO3 (42YX-LT) substrate could be obtained. In this study, we investigated this layer structure and found that a two-layer structure, in which the AlN layer is removed, achieves a high $Q$ -factor. Numerical analyses using a finite element method showed that the acoustic wave energy can be confined to the surface of the two-layer substrate, and the TCF and electromechanical coupling coefficient ( $k^{2}$ ) were improved by optimizing the thickness of each layer. We fabricated and evaluated prototype one-port resonators with the two-layer structure and the standard 42YX-LT SAW substrate with resonant frequencies from 0.95 to 3.6 GHz. An improvement of the Q-factor of 3 to 4 times compared with that of the resonator with standard 42YX-LT substrate was observed for the two-layer structure, which means that a reduction of complexity of the layer structure could be obtained without performance loss. The two-layer structure was applied to a 2.4-GHz band Wi-Fi filter to achieve high performances such as low-loss, better steepness, and high attenuation.

To develop the high-performance filters and duplexers required for recent long-term evolution frequency bands in mobile handsets, a surface acoustic wave (SAW) resonator is needed that has a higher quality (Q) and a lower temperature coefficient of frequency (TCF). To achieve this, the authors focused on acoustic energy confinement in the depth direction for a rotated Y-X LiTaO3 (LT) substrate. Characteristics of multilayered substrates with low-impedance and high-impedance layers under LT layer were studied numerically in terms of acoustic energy distribution, phase velocity, coupling coefficient, and temperature characteristics employing a finite-element method simulation. After several calculations, a novel multilayered structure was developed that uses SiO2 for a low-impedance layer and AlN for a high-impedance layer under the thin LT layer. A one-port resonator using the new substrate was fabricated, and its experimental results showed that the developed resonator had a Bode-Q over 4000 and TCF of −8 ppm/°C, which are four times higher than and one-fifth as small as those of a conventional 4° YX-LT SAW resonator, respectively. By applying this technology, a band 25 duplexer with very narrow duplex gap was successfully developed, which shows extremely low insertion loss, steep cutoff characteristics, and stable temperature characteristics.

In this paper, we study a velocity reduction of incredible high performance (I.H.P.) surface acoustic wave (SAW). First, variations of I.H.P. SAW velocity and fractional bandwidth with thickness of Pt layer in Al/Pt electrode are estimated using a finite element method simulator, and specific conditions where the SAW velocity can be reduced maintaining the fractional bandwidth equivalent to that of the conventional structure are determined. Then some one-port resonators under the determined conditions are fabricated and their velocity, fractional bandwidth, quality factor, and temperature stability are evaluated. As the result, it is indicated that, by using Al/Pt electrode and by adjusting the film thicknesses of a multilayer substrate, the velocity of I.H.P. SAW is successfully reduced while keeping other important characteristics.

In response to the increased mobile data traffic, there is a growing need for more low-loss RF band filters with steep frequency characteristics, and high-quality ( Q )-factor and low-temperature coefficient of frequency (TCF) resonators are required to achieve this. We previously reported that for a surface acoustic wave (SAW) resonator on a three-layer structure, which is composed of a thin LiTaO

In this work, a technique to reduce the acoustic velocity of incredible high-performance surface acoustic wave (I.H.P. SAW) using Al/Pt electrodes keeping other important characteristics such as fractional bandwidth and quality factor is proposed. First, using a finite element method simulator, variations of the acoustic velocity and the fractional bandwidth of the I.H.P. SAW with the Pt electrode thickness, thicknesses of LiTaO3 (LT) and SiO2 layers in a substrate, and the cut angle of a LT layer are estimated. And then, to confirm the validity of the estimation results, several one-port SAW resonators with various thickness combinations of Al, Pt, LT, and SiO2 layers are fabricated and their characteristics are evaluated. The evaluation results show that the acoustic velocity of the I.H.P. SAW is successfully reduced keeping the bandwidth, the quality factor, and the temperature characteristics.

Regarding higher frequency above 3 GHz, up until now BAW filters have been believed to be better solution than SAW filters due to their increase of electrodes resistance. This paper describes a new high performance SAW filter surpassing BAW, with 3.5 GHz center frequency employing I.H.P. SAW technology which is new type SAW structure with high Q factor. Experimental studies for one-port resonators in 3.6 GHz show very high Bode-Q max of 2500 and optimum aperture lengths of IDTs. Using the results, a ladder type filter for LTE Band 42 was designed and fabricated. Very low insertion loss of 1.7 dB max has been achieved in the passband of $\mathbf{3.5+/-0.1 \ GHz}$:. Steeper skirt characteristics and adequate attenuation have been also realized.

We discuss transverse modes in a resonator on a multilayer substrate with a thin piezoelectric plate. A generation mechanism of the transverse mode response in I.H.P. SAW (Incredible High-Performance SAW)resonator with a LiTa03 plate is analyzed by using FEM simulations, and it is shown that a slowness curve of the I.H.P. SAW structure is changed significantly compared with a standard 42° Y-X LiTa03 substrate. A new tilted resonator structure is proposed to suppress the transverse mode spurious. It is found that the tilted resonator with a small tilted angle can suppress the spurious response successfully with maintaining a high-Q factor.

I.H.P. SAW (Incredible High-Performance SAW) has a novel multi-layered structure to confine SAW energy in substrate surface area, and it shows extremely high quality (Q) factor, low temperature coefficient of frequency (TCF) and improved electromechanical coupling coefficient (K2). This paper introduces its mechanism of the high acoustic Q factor, both theoretically and experimentally, and its applications to new LTE band filters and multiplexers for Carrier Aggregation service.

Various characteristics for RF filters in mobile terminals are required corresponding to expansion of mobile terminals. I.H.P. SAW (Incredible High-performance SAW) with high Q and temperature stability has been developed to resolve these challenges. In this paper, its high Q mechanism of the new multi-layered structure (LiTaO 3 / SiO 2 / AlN / Si substrate) has been studied numerically in terms of acoustic energy confinement by using wave propagation analysis in real-space and wavenumber domains. One-port resonators employing I.H.P. SAW were fabricated after optimizing the multi-layered structure. Experimental results show higher Bode-Q values over 6000 at 0.9 GHz to 1900 at 3.5GHz successfully, which are over 3 times higher than those of conventional 42YX-LT SAW resonators. Very small TCF of −8 ppm/°C is also realized, and wider bandwidth and superior heat dissipation performance have been achieved. A new Wi-Fi filter with very narrow adjacent gaps and a new Band 25 / 66 / 30 hexaplexer, one of the most difficult multiplexers, have been developed using I.H.P. SAW technology, which show low insertion loss, steep cut-off, deep attenuation and extremely high isolation characteristics.

To develop the high-performance filters and duplexers required for recent long-term evolution frequency bands in mobile handsets, a surface acoustic wave (SAW) resonator is needed that has a higher quality (Q) and a lower temperature coefficient of frequency (TCF). To achieve this, the authors focused on acoustic energy confinement in the depth direction for a rotated Y-X LiTaO

High Q and low TCF are elemental characteristics for SAW resonator, in order to realize high performance filters and duplexers for new LTE frequency bands. Authors have focused on the acoustic energy confinement in vicinity of substrate surface. A novel multi-layered structure substrate have realized incredibly high performances such as Q factor of 4000 and TCF of 8 ppm/°C compared with conventional structure.

High Q and low TCF are elemental characteristics for SAW resonator, in order to realize high performance filters and duplexers coping with new LTE frequency bands. Authors focus on the acoustic energy confinement in SAW propagation surface and electrical characteristics have been investigated theoretically and experimentally. A new multi-layered structure substrate have realized incredible high performances such as both three times Q and one fifth TCF compared with conventional structure. Band25 duplexer using the new structure has been developed successfully with low loss and good temperature stability.

イベント相関解析法には，イベント発生点間のタイムラグの分散が大きいと，物理的に関係を有するイベント間であっても，バイナリ変換時のタイムウィンドウ幅を適切に選ばなければ，イベント発生系列間の類似性を誤判定してしまう問題があった．このような問題に対して，適切なタイムウィンドウ幅を自動的に選択し，イベント発生系列間の類似性を正しく判定できる新しいイベント相関解析法が提案されている．本論文では，この新しいイベント相関解析法を，代表的な大規模化学プラントであるエチレンプラントの運転ログデータに適用し，従来のイベント相関解析法では類似度を低く推定していたタイムラグの分散が大きいイベント間の類似度を，タイムウィンドウ幅を自動調整することで正しく評価できることを確認した．また，類似度の評価結果に基づきグループ化されたイベント群を詳しく分析した結果，プラント運転ログデータから迷惑アラームや定型操作を抽出できることを示した．

Event correlation analysis is a data-mining method that detects statistical similarities among discrete occurrences of alarms or operations. By grouping correlated events based on degree of similarity, a policy for reducing alarms and operations can be designed more easily than by analyzing individual alarms and operations. In this study, event correlation analysis was applied to event log data at an Idemitsu Kosan ethylene plant in Japan to reduce the number of alarms and operations, where events are defined by both tag names and types of tag. The obtained results were helpful for identifying unnecessary alarms and operations, such as sequential alarms and routine operations, buried in a lot of noisy plant data. Copyright © 2011 Curtin University of Technology and John Wiley & Sons, Ltd.

Radioimmunoassay (RIA) was investigated for the determination of TA-0910 and its main metabolite, TA-0910 acid-type, in human plasma and urine. TA-0910 is a new metabolically stable analogue of thyrotropin releasing hormone (TRH). Antiserum was raised in the rabbit against the 1-fluoro-2,4-dinitrophenyl derivative of TA-0910 or TA-0910 acid-type conjugated to keyhole limpet hemocyanin (KLH). The radioligand was prepared by iodination with 125I of the histidine imidazole ring of TA-0910 or TA-0910 acid-type. Cross-reactivities of anti-TA-0910 or TA-0910 acid-type antiserum for TA-0910, its metabolite and related compounds were low. The calibration range was 0.02–5 ng ml−1 using 100 μl human plasma or urine. Inter-day variations of TA-0910 and TA-0910 acid-type assay in plasma were 3.5–15.5 and 1.8–9.4%, respectively. The variations of the assay in urine were the same as those in plasma. The recovery of TA-0910 and TA-0910 acid-type spiked in plasma or urine samples was approximately 100%. Furthermore, this method was applied to the determination of TA-0910 and TA-0910 acid-type in human plasma and urine samples, for the evaluation of the pharmacokinetics of TA-0910 in humans. From the results it was demonstrated that he developed RIA was useful for the determination of TA-0910 and TA-0910 acid-type in human plasma and urine, and was applicable to pharmacokinetic studies in humans.

Alarm management efforts have recently intensified in the world, and there are many tools based on a guideline EEMUA191 to evaluate alarm system performance. However, the improvement and rationalization of alarm systems have not made satisfactory progress, because these tools usually just provide with alarm system performance metrics but not useful information to improve and rationalize alarm systems. In this paper, a novel method for performance improvement of IPL2&3 including alarm system using the event correlation analysis was proposed.

Event correlation analysis was applied alarm data at an Idemitsu Kosan ethylene plant in Japan to reduce the number of plant alarms. This is a data-mining method that detects statistical similarities among discrete occurrences of alarms or operations. By grouping correlated events based on degree of similarity, a policy for reducing alarms can be designed more easily than by analyzing individual alarms and operations. By using event correlation analysis, we were able to divide event data of alarms or operations of the ethylene plant into a limited number of groups. The results of the analysis were helpful for identifying unnecessary alarms, such as sequential alarms, buried in a lot of noisy plant data. This method is useful for reducing the number of alarms.

Dissolution profiles of griseofulvin (GRF) dispersed in water-soluble polymers were investigated by the paddle method, and large differences in dissolution behavior were observed with different kinds of polymers. The quantitative relationship of dissolution behavior with several properties of the polymers was investigated by the application of multiple regression analysis. It was found that the degree of crystallinity of GRF, the wetting of samples, the solubility or insolubility of water-soluble polymers in methanol, the viscosity of polymer solution and the dissolution rate of polymers were important in the analysis of dissolution mechanisms and prediction of dissolution profiles of GRF from these systems.

A computer optimization technique was applied to obtain griseofulvin (GRF)/hydroxypropyl cellulose (HPC) solid dispersions which provide a high dissolution rate and good stability of dissolution properties. The amounts of HPC and methanol were selected as independent variables in the regression analysis (methanol was used for the preparation of the solid dispersions). Concentrations of GRF dissolved in the dissolution medium at each sampling time were selected as dependent variables for deciding the optimum formulation. These dissolution characteristics were predicted quantitatively by using the best combination of independent variables. The physical meaning of the regression equation for each dissolution characteristic was defined by the application of contour graphs. Two hundred mg of GRF, 2 g of HPC and 125 ml of methanol was predicted to be the optimum for the preparation of GRF/HPC solid dispersions. Experimental results with this optimized solid dispersion agreed well with the predictions.

This paper describes experimental work on control of solid propellant combustion with laser heating. Burning rates of HTPB/AP composite solid propellants were measured at pressures up to 200 kPa with laser power densities up to 2.1 W mm. With our (fuel-rich) non-self combustible solid propellants, the combustion control, including ignition and interruption by switching on/off the laser, was feasible, and the burning rate coincidentally obeyed Vieille’s law with pressure exponents of approximately 0.3. Hence, this combustion control with the laser irradiation seems to be applicable to space propulsion for microsatellites. The heat feedback rate from flame to burning surface, Hf, was estimated from the burning rate variation with laser power density. In case with the fuel-rich solid propellant, Hf increased from 2 to 7 W mm in keeping with back pressure from 30 to 200 kPa. This suggests that approximately 70% of the energy to the burning surface is provided by the combustion itself, and the rest 30 % is supplied by the laser as the supplementary heat flux to compensate for the heat insufficiency for combustion sustenance.