Improved Operating Characteristics Research Articles

Optimization of an IPMSM for Constant-Angle Square-Wave Control of a BLDC Drive

Interior permanent magnet synchronous machines (IPMSMs) driven with a square-wave control (i.e., six-step, block, or 120° control), known commonly as brushless direct current (BLDC) drives, are used widely due to their high power density and control simplicity. The advance firing (AF) angle is employed to achieve improved operation characteristics of the drive. The AF angle is, in general, applied to compensate for the commutation effects. In the case of an IPMSM, the AF angle can also be adjusted to exploit reluctance torque. In this paper, a detailed study was performed to understand its effect on the drive’s performance in regard to reluctance torque. Furthermore, a multi-objective optimization of the machine’s cross-section using neural network models was conducted to enhance performance at a constant AF angle. The reference and improved machine designs were evaluated in a system-level simulation, where the impact was considered of the commutation of currents. A significant improvement in the machine performance was achieved after optimizing the geometry and implementing a fixed AF angle of 10°.

Optimization of the Copper Microstructure to Improve Copper-to-Copper Direct Bonding

Advanced packaging solutions and heterogeneous integration are key technologies to enable devices with improved operating characteristics, including higher performance, increasing power efficiency, and decreasing form factor. Packages with high interconnect densities are required to efficiently combine, e.g., processing and memory units but impose restrictions to the pitch of the interconnects. Conventional technologies, including wire bonds and flip chip bonds are limited to larger pitches and, therefore, not suitable to meet the requirements of upcoming packaging technologies with respect to interconnect densities. Direct copper-to-copper interconnects are supposed to allow such small pitches of 10 µm or even below. However, formation of such bonds usually requires high temperatures and pressures. Temperature-sensitive devices like DRAM components restrict the maximum temperature that can be applied to the package. Thus, copper material is required, which allows bond formation at relatively low temperatures. In this context, hybrid bonding processes were discussed that involve initial bond formation via the usually oxide-based dielectric at room temperature followed by copper-to-copper bonding at elevated temperatures. The copper material is usually prepared by electrolytic deposition and the properties of the respective deposits may be modified by properly designed organic additives as well as process parameters. Strong bond formation of the copper should be obtained upon grain growth over the interface of the two deposits, which are brought into contact during the bonding step. In order to facilitate such growth at relatively low temperatures, suitable microstructures need to be prepared. Ideally, morphologies should be chosen in a way that they can be maintained throughout all process steps after the electrolytic deposition but, at the same time, allow grain growth over the interface during copper-to-copper bonding. Various strategies to enable improved seamless grain growth but maintain a metastable microstructure throughout the preceding process steps and the corresponding unique copper microstructures will be compared. In this context, different electrolytic copper deposition processes, the resulting microstructures, as well as their respective advantages and challenges with regards to copper-to-copper bond formation will be discussed.

Nanomodified Epoxy Materials with Improved Operating Characteristics

The purpose of the work is to develop new polymer composite nanomodified materials for the restoration of hull parts of agricultural machinery.As a result of research, a comparative analysis of the properties of composites based on epoxy resin ED-20 with the addition of 0.1-1.5 mass parts of carbon nanotubes “Taunit-M” obtained by free casting and direct pressing was carried out. The effectiveness of the developed compositions is proved when using them as binders in the production of fiber-reinforced composites.It was found that the introduction of 0.5 to 1 mass. parts CNT "Taunit" allows you to increase the strength characteristics of the resin ED-20 1.5-4 times with uniaxial tension, 2-2.5 times with three-point bending and reduce weight wear by 5-10 times.

Modern trends in the processing of linear alpha olefins to technologically important products. Part 1

Linear alpha olefins (LAO) form a class of chemical compounds that are used in the production of highly marketable products, such as plasticizers, synthetic lubricants, surfactants and (co)polymers with the improved operating characteristics. Since the annual world consumption of LAO derivatives is growing, specialists from research institutes, universities and industrial laboratories become involved in LAO processing. The analysis of scientific literature published in recent ten years revealed the absence of general reviews devoted to LAO processing. This review considers modern trends in the processing of LAO, which contain four and more carbon atoms, to technologically important derivatives. General information on the main products obtained by LAO processing, methods of their production and application fields is reported. The existing technological processes used to obtain LAO derivatives as well as the catalysts employed in the processes are briefly described. The review presents modern trends in LAO processing and promising ways for enhancing the available technologies, particularly the development of new types of catalysts. Authors of the review make no pretence to a comprehensive or detailed presentation of the material; the main aim was to give a general idea of the main directions in LAO processing, the catalysts used in such processes, and the advanced approaches to their improvement.

Development and Validation of a Magnetic Resonance Index for Assessing Fistulas in Patients With Crohn’s Disease

There is no validated magnetic resonance imaging (MRI) index for assessment of perianal fistulas in patients with Crohn's disease (CD). We developed and internally validated a new instrument. We used paired baseline and week-24 MRI scans from 160 participants in a randomized placebo-controlled trial of stem cell therapy for patients with perianal fistulizing CD. Four radiologists scored disease activity using index items identified during previous studies and exploratory items. Reliability was assessed using intraclass correlation coefficients. We developed an index using backward elimination linear regression analysis, in which potential independent variables were items having intraclass correlation coefficients of at least 0.4 and the dependent variable was perianal fistulizing disease activity, measured on a 100-mm visual analogue scale. The final model was internally validated using the .632 bootstrap method to correct model optimism and quantify calibration accuracy. We evaluated responsiveness of the index by assessing longitudinal validity and estimating standardized effect sizes. We developed the magnetic resonance novel index for fistula imaging in CD (MAGNIFI-CD) using 6 items. The optimism-corrected R2 of the model was 0.71, which was comparable to R2 for the original sample (0.74). The calibration slope for the model was 0.98. Compared with the original and modified versions of the Van Assche Index, the MAGNIFI-CD had improved operating characteristics. Estimates of intraclass correlation coefficients for MAGNIFI-CD, the modified Van Assche Index, and Van Assche Index were 0.85 (95% confidence interval [CI], 0.77-0.90), 0.81 (95% CI, 0.74-0.86), and 0.81 (95% CI, 0.71-0.86) for intra-rater reliability, and 0.74 (95% CI, 0.63-0.80), 0.67 (95% CI, 0.55-0.75) and 0.68 (95% CI, 0.56-0.77) for inter-rater reliability. Corresponding standardized effect size estimates were 1.02 (95% CI, 0.65-1.39), 0.84 (95% CI, 0.48-1.21), and 0.68 (95% CI, 0.33-1.03). We developed an index called the MAGNIFI-CD, which is based on 6 items. It assesses MRI data and determines perianal fistulizing CD activity with improved operating characteristics compared to previous indices. This index may be used as an outcome measure in clinical trials comparing treatment effects in patients with perianal fistulizing CD. Although the performance of the MAGNIFI-CD indicates its stability and reasonable external validity, external validation is needed.

Measuring Exposure to Incarceration Using the Electronic Health Record.

Electronic health records (EHRs) are a rich source of health information; however social determinants of health, including incarceration, and how they impact health and health care disparities can be hard to extract. The main objective of this study was to compare sensitivity and specificity of patient self-report with various methods of identifying incarceration exposure using the EHR. Validation study using multiple data sources and types. Participants of the Veterans Aging Cohort Study (VACS), a national observational cohort based on data from the Veterans Health Administration (VHA) EHR that includes all human immunodeficiency virus-infected patients in care (47,805) and uninfected patients (99,060) matched on region, age, race/ethnicity, and sex. Self-reported incarceration history compared with: (1) linked VHA EHR data to administrative data from a state Department of Correction (DOC), (2) linked VHA EHR data to administrative data on incarceration from Centers for Medicare and Medicaid Services (CMS), (3) VHA EHR-specific identifier codes indicative of receipt of VHA incarceration reentry services, and (4) natural language processing (NLP) in unstructured text in VHA EHR. Linking the EHR to DOC data: sensitivity 2.5%, specificity 100%; linking the EHR to CMS data: sensitivity 7.9%, specificity 99.3%; VHA EHR-specific identifier for receipt of reentry services: sensitivity 7.3%, specificity 98.9%; and NLP, sensitivity 63.5%, specificity 95.9%. NLP tools hold promise as a feasible and valid method to identify individuals with exposure to incarceration in EHR. Future work should expand this approach using a larger body of documents and refinement of the methods, which may further improve operating characteristics of this method.

Electron mobility enhancement in solution-processed low-voltage In2O3 transistors via channel interface planarization

The quality of the gate dielectric/semiconductor interface in thin-film transistors (TFTs) is known to determine the optimum operating characteristics attainable. As a result in recent years the development of methodologies that aim to improve the channel interface quality has become a priority. Herein, we study the impact of the surface morphology of three solution-processed high-k metal oxide dielectrics, namely AlOx, HfOx, and ZrOx, on the operating characteristics of In2O3 TFTs. Six different dielectric configurations were produced via single or double-step spin-casting of the various precursor formulations. All layers exhibited high areal capacitance in the range of 200 to 575 nF/cm2, hence proving suitable, for application in low-voltage n-channel In2O3 TFTs. Study of the surface topography of the various layers indicates that double spin-cast dielectrics exhibit consistently smoother layer surfaces and yield TFTs with improved operating characteristics manifested, primarily, as an increase in the electron mobility (µ). To this end, µ is found to increase from 1 to 2 cm2/Vs for AlOx, 1.8 to 6.4 cm2/Vs for HfOx, and 2.8 to 18.7 cm2/Vs for ZrOx-based In2O3 TFTs utilizing single and double-layer dielectric, respectively. The proposed method is simple and potentially applicable to other metal oxide dielectrics and semiconductors.

Improvement of Operation Characteristics for MONOS Charge Trapping Flash Memory with SiGe Buried Channel**Supported by the National Science and Technology Major Project of China under Grant No 2013ZX02303007, the National Key Research and Development Program of China under Grant No 2016YFA0301701, and the Youth Innovation Promotion Association of the Chinese Academy of Sciences under Grant No 2016112.

We propose and investigate a novel metal/SiO2/Si3N4/SiO2/SiGe charge trapping flash memory structure (named as MONOS), utilizing SiGe as the buried channel. The fabricated memory device demonstrates excellent program-erasable characteristics attributed to the fact that more carriers are generated by the smaller bandgap of SiGe during program/erase operations. A flat-band voltage shift 2.8 V can be obtained by programming at +11 V for 100 μs. Meanwhile, the memory device exhibits a large memory window of ∼7.17 V under ±12 V sweeping voltage, and a negligible charge loss of 18% after 104 s’ retention. In addition, the leakage current density is lower than 2.52 × 10−7 A·cm−2 below a gate breakdown voltage of 12.5 V. Investigation of leakage current-voltage indicates that the Schottky emission is the predominant conduction mechanisms for leakage current. These desirable characteristics are ascribed to the higher trap density of the Si3N4 charge trapping layer and the better quality of the interface between the SiO2 tunneling layer and the SiGe buried channel. Therefore, the application of the SiGe buried channel is very promising to construct 3D charge trapping NAND flash devices with improved operation characteristics.

Improved Operation Characteristics for Nonvolatile Charge-Trapping Memory Capacitors with High-κ Dielectrics and SiGe Epitaxial Substrates**Supported by the National Science and Technology Major Project of China under Grant No 2013ZX02303007, the National Key Research and Development Program of China under Grant No 2016YFA0301701, and the Youth Innovation Promotion Association of the Chinese Academy of Sciences under Grant No 2016112.

A novel high-κ Al2O3/HfO2/Al2O3 nanolaminate charge trapping memory capacitor structure based on SiGe substrates with low interface densities is successfully fabricated and investigated. The memory capacitor exhibits excellent program-erasable characteristics. A large memory window of ∼4 V, a small leakage current density of ∼2 × 10−6 Acm−2 at a gate voltage of 7 V, a high charge trapping density of 1.42 × 1013 cm−2 at a working voltage of ±10 V and good retention characteristics are observed. Furthermore, the programming ( at 10 V for 10 μs) and erasing speeds ( at −10 V for 10 μs) of the fabricated capacitor based on SiGe substrates are significantly improved as compared with counterparts reported earlier. It is concluded that the high-κ Al2O3/HfO2/Al2O3 nanolaminate charge trapping capacitor structure based on SiGe substrates is a promising candidate for future nano-scaled nonvolatile flash memory applications.

A gain‐switched self‐optimizer for braking controller

SummaryAn emergency braking controller is developed with improved operation characteristics near the maximum friction zone. The methodology is based on self‐seeking a‐priori unknown optimum operation point to maximize a performance function representing the optimal behavior of the considered dynamic system. Sliding mode with uncertain direction of control vector approach is utilized in the algorithm. An adaptive variable gain is utilized in the algorithm to improve its performance. Via the variable gain, both fast convergence to the a‐priori unknown optimum operation point and reduced magnitude of oscillations in the braking moment inputs resulting less aggressive control action are achieved. Copyright © 2016 John Wiley & Sons, Ltd.

CVD Deposited Titania Thin Films for Gas Sensors with Improved Operating Characteristics

This paper describes the results of experimental evaluation of titanium dioxide thin films formed by CVD as active layers in semiconductor, resistive sensors for detection of ethanol vapors. TiO2 layers with a thickness of 90 nm are formed by CVD in the TTIP‐O2‐O3‐Ar reaction system. Sensors manufactured with titania films formed under all the deposition conditions studied exhibit good electrical response to the ethanol vapors, with quick response‐recovery characteristics in the temperature range 170–300 °C. Sensor performance is determined by the relative amount of anatase phase and grain size in the films. The response value (Rair/Rethanol) of the sample with the highest degree of crystallinity reached 37 at an operating temperature of 200 °C.

Investigation of the Physico-Mechanical and Thermophysical Properties of Epoxy Composites with a Two-Component Bidisperse Filler

The effect of two-component bidisperse filler on the physico-mechanical and thermophysical properties of epoxy composites has been studied. A coating with an aluminum oxide content of 60 parts by weight and a crystalline boron content of 40 parts by weight per 100 parts by weight of ED-20 epoxy oligomer and 10 parts by weight of a hardener (polyethylenepolyamine) with improved operating characteristics has been developed. The reliability of the obtained results is verified by modern methods of investigation, i.e., by the thermogravimetric and differential thermal analysis of materials under investigation.

5상 1.5kW 농형 유도전동기의 운전특성

This paper presents an improved operating characteristics of squirrel-cage induction motor(IM) for 5-phase 1.5kW, 220V, 60Hz in order to study a polyphase AC machinery that keep hold of advantages more than traditional three-phase a IM, such as reducing a amplitude of torque pulsation, decreasing electric noises, and increasing the reliability. The developed manufacturing motor was necessary to do improvement of speed regulation, efficiency, operating characteristics, and so on at rated load. There are remake a redesigned and distributed stator winding connection without changing the frames of stator and rotor core in previous established the motor by a repeat tests. There are shown a experiments results of no-load test, locked rotor test, operating characteristics at variable load, FFT analysis of harmonics within output voltages and current waveform, decided motor parameters.

Double nut ball screw with improved operating characteristics

The performance and availability of production machines is strongly affected by the operating characteristics of the installed ball screws. In this context, the value of preloading is an important property greatly influencing the quality of the feed motion as well as the expected service life. Dynamic applications often require ball screws with high preloading values. As a result, such systems typically suffer from high friction values with the involved wear and heat generation. This paper presents a novel design principle for ball screws, allowing for a considerable reduction of the preloading and hence an overall improvement of the operating characteristics.

Improved Operation Characteristics in Charge-Trapping Flash Memory Devices With Engineered Dielectric Stack, Sige and Junctionless Poly-Si Channels

not Available.

5상 5kW 표면부착형 영구자석 동기발전기 특성개선

5상 5kW 표면부착형 영구자석 동기발전기 특성개선

(Invited) Improved Operation Characteristics in Charge-Trapping Flash Memory Devices with Engineered Dielectric Stack and SiGe Channel

Programming and retention characteristics of charge-trapping (CT) non-volatile memory (NVM) devices can be enhanced by inserting Al2O3 between Si3N4 and HfO2 as the charge-trapping layer. This is because most of the injecting charges are trapped at Si3N4/Al2O3 interface and Al2O3 also provides a high barrier for electron detrapping. In addition, Compare to those with conventional Si-channel, both programming and erasing speeds are significantly improved by employing a Si0.7Ge0.3 buried channel. Satisfactory retention and excellent endurance characteristics up to 106 P/E cycles with 4.1 V memory window show that the degradation on reliability properties, if it exists, is negligible when SiGe buried channel is introduced.

Analysis and Control of Starting Current of Three Phase Induction Motor by Fuzzy Logic Controller

Variable speed drives are growing and varying. Drives expanse depend on progress in different part of science like power system, microelectronic, control methods, and so on. electrical drive control. With the use of space vector technique to electrical drive control the, efficiency and reliability of drives increase and volume, weight and cost of them decrease. Due to the improved operating characteristics they give to the equipment control, Escalators pumps, elevators and conveyor belts all operate more effectively if they are soft started. In turn, the SVPWM method and FLC method reduces maintenance, conserves energy and plays a significant part in improving plant performance and operating costs.

KAOLIN PROCESSING USING FUZZY HYDROCYCLONE CONTROL

In many cases, the hydrocyclone control is desirable for efficient separation especially in case of changing feed conditions. Control concept based on exact mathematical models is not satisfactory due to the complexity of the physical process. In this case, fuzzy control is a suitable solution. The data are primarily derived from an optical sensor that monitors the outside view of the free underflow stream (spray angle). A throttling valve, serving as an actuator, is installed around the overflow pipe that regulates the volume split of the cyclone. This work presents a fuzzy hydrocyclone control to stabilize the separation, as a result of varying feed conditions in kaolin processing. The aim is to control the final product size (kaolin) and then to replace the multi-stages hydrocyclones which are currently used with only one stage fuzzy controlled hydrocyclone separation process to produce high quality kaolin in the overflow product even with changing the feed conditions during the separation. The results showed that sharp separations are performed with a spray angle in the range of 25° to 35°. Therefore, in that application, the control is focused on stabilization of the spray angle. A controlled spray angle of 26° was found to give optimum results concerning the kaolin quality separated in the overflow. The improved operation characteristics present new options for extensive applications of fuzzy hydrocyclone control.

블로킹커패시터를 이용한 향상된 위상천이 펄스폭변조 풀브리지 컨버터

This paper presents an improved phase-shift pulse-width modulation (PWM) full-bridge converter using a blocking capacitor. As the proposed converter reduces the circulation energy by inserting only one series blocking capacitor at the primary side of the conventional phase-shift PWM full-bridge converter structure, it improves the operation characteristics of the conventional converter. In this paper, first, the operation of conventional phase-shift PWM full-bridge converter is roughly reviewed, and then the operational principle of the proposed converter is classified and explained by each mode. After that, a prototype design example based on the operational principle is shown. Then, the improved operation characteristics of the proposed converter are actually verified through the experimental results.