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3,4,8,9-Fluoranthenetetracarboxylic diimides (FDI) are first synthesized as stable yellow compounds by the Diels-Alder (DA) reaction of maleic anhydride and acecyclone derivative bearing an acenaphthylene imide unit and subsequent imidations. An X-ray crystallographic analysis of di(N-octyl)FDI derivative reveals the planar fluoranthene diimide π -system. The cyclic voltammograms of FDIs shows considerably high electron affinity. Moreover, its π -extended analogue involving an anthracene unit (DAAI) was also prepared by the DA reaction of acenaphthylene-3,4-dicarboxylic imide with o-xylylene derivative. The compound exhibits long wavelength absorption and intense fluorescence with moderate solvatofluorochromism (ΔλEM = 41 nm). Theoretical calculations based on density function theory (DFT) were performed to characterize the electronic feature of these diimides.

Although azomethine ylides have been fully exploited as versatile reactive intermediates in dipolar cycloaddition reactions to construct a variety of heterocyclic compounds involving a nitrogen atom, little is known about their structural and electronic properties. Here a method is developed for the preparation, isolation and characterization of a stable 2-azaphenalenyl based azomethine ylide. N-Phenyl-5,8-di-t-butyl-2-azaphenalenyl cannot be isolated because it undergoes rapid dimerization by C–C bond formation at the 1 and 3 positions. In contrast, sterically bulkier N-2,6-di(isopropyl)phenyl-5,8-di-t-butyl-2-azaphenalenyl can be generated and isolated as deep green crystals under deoxygenated conditions. X-ray crystal analysis of this stable azomethine ylide reveals that its azaphenalenyl skeleton has very small bond alternation and structural deformation. The results of spectroscopic and electrochemical theoretical studies indicate that N-2,6-di(isopropyl)phenyl-5,8-di-t-butyl-2-azaphenalenyl has electronic features that are similar to those of phenalenyl anion and it possesses an extremely high HOMO energy. Azomethine ylides have long been identified as reactive intermediates in organic synthesis, but very little concrete structural data has been obtained. Here the authors report on the preparation, isolation and characterization of a stable 2-azaphenalenyl-based azomethine ylide.

We have developed neuromorphic computing based on Analog ReRAM, Resistive Analog Neuromorphic Device (RAND), as low power solution for edge application. We have proposed perceptron circuit which has resistive elements to store weights as analog resistance and binarizes output from each layer in order to realize large scale integration and keep high accuracy. We have fabricated 180nm test chip by using mass production process and we have demonstrated MNIST recognition and sensor application in flexible network architecture in which several neural networks can be configured at the same time. We present potential of low power solution by scaling down to 40nm node under development and reliability issues to be considered in neural network processors based on analog nonvolatile memories.

We present reliability issues to be considered in neural network (NN) processors based on analog nonvolatile memories. We developed a reliability model of resistive random access memory (ReRAM). In this model, the properties of conductive filament control the reliability characteristics. A ReRAM based neural-network processor is also demonstrated. Using well-controlled analog currents, we realized MNIST handwritten digits dataset recognition with low power. Furthermore, the difference in handling reliability for digital memory and analog NN processor is discussed. We propose an NN simulation based on ReRAM reliability model in order to consider the reliability of analog NN processor.

We have fabricated a novel hydrogen sensor using optimized 0.18-μm ReRAM process. Our ReHsensor (Resistive Hydrogen Sensor) conforms with the ISO26142 standard in that it exhibits exceptional sensing capabilities, including high sensitivity, wide hydrogen concentration range (up to 4 vol.%) in air and N 2 ambient, high gas selectivity (no reaction with CH 4 , CO, CO 2 , CH 3 OH, and CH 3 COCH 3 ) and is immune to poisoning by SO 2 and hexamethyl disiloxane (HMDS). As it does not require a heater, the power consumption of the ReHsensor is very low, at 0.35 mW. We used this hydrogen sensor device to develop a battery-powered all-in-one wireless hydrogen sensor unit for IoT applications.

This paper presents low-power neural-network (NN) processor using ReRAM to store weights as analog resistance for future AI computing. We propose ReRAM perceptron circuit for realizing large scale integration, highly accurate cell current controlled writing scheme, and flexible network architecture (FNA) in which any NNs can be configured. Fabricated 180nm test chip shows well-controlled analog cell current with linear 30μA dynamic range and 0.59μA variation of 1 sigma, results in 90.8% MNIST numerical recognition rate. Furthermore, 4M synapses integrated 40nm test chip achieves lower analog cell current and 66.5 TOPS/W power efficiency.

SUMMARY InGaN green laser diodes (LDs) on semipolar GaN substrates with output powers of over 100 mW in the spectral region beyond 530 nm are demonstrated. Wall plug efficiencies as high as 7.0–8.9% are realized in the wavelength range of 525–532 nm, exceeding those reported for c-plane LDs. The lifetime at a case temperature of 55 °C was estimated to be over 5000 hours for an optical output power of 50 mW. These results suggest that InGaN green LDs on the plane are better suited as light sources for applications requiring wavelengths above 525 nm.

We revisit class number formulas, “ s = 0 ”-version of Kroneckerʼs limit formulas and Chowla–Selberg formulas for number fields, based on the theory at s = 0 of zeta functions. The main tool in our investigation is Heckeʼs formula (Corollary to Theorem 1), which represents the zeta function of an algebraic number field K by the integral of Epsteinʼs zeta series summed over Z r . The formulas are derived without residue computations of zeta functions. Theorem 2 for class numbers is quite useful. For Chowla–Selberg formulas, the second gamma function with a character is utilized.

The retention model of a bipolar ReRAM considering the percolative paths in a conductive filament is proposed. We demonstrate, for the first time, that the control of oxygen vacancy concentration in a conductive filament is the key for ensuring data retention including tail bits. To improve the retention property under low-current operation, the size of the conductive filament must be scaled down while keeping the density of oxygen vacancy high enough. Based on this concept, we demonstrate both low-current operation and sufficient retention results exceeding 500 h at 150°C, which correspond to more than 10 years at 85°C.

An analytic formula based on stochastic differential equation is successfully developed to describe intrinsic ReRAM variation. The formula is useful to predict scaled ReRAM memory window after retention, verified by testing 40 nm 2Mb memory array.

The apicoplast housekeeping machinery, specifically apicoplast DNA replication, transcription, and translation, was targeted by ciprofloxacin, thiostrepton, and rifampin, respectively, in the in vitro cultures of four Babesia species. Furthermore, the in vivo effect of thiostrepton on the growth cycle of Babesia microti in BALB/c mice was evaluated. The drugs caused significant inhibition of growth from an initial parasitemia of 1% for Babesia bovis , with 50% inhibitory concentrations (IC 50 s) of 8.3, 11.5, 12, and 126.6 μM for ciprofloxacin, thiostrepton, rifampin, and clindamycin, respectively. The IC 50 s for the inhibition of Babesia bigemina growth were 15.8 μM for ciprofloxacin, 8.2 μM for thiostrepton, 8.3 μM for rifampin, and 206 μM for clindamycin. The IC 50 s for Babesia caballi were 2.7 μM for ciprofloxacin, 2.7 μM for thiostrepton, 4.7 μM for rifampin, and 4.7 μM for clindamycin. The IC 50 s for the inhibition of Babesia equi growth were 2.5 μM for ciprofloxacin, 6.4 μM for thiostrepton, 4.1 μM for rifampin, and 27.2 μM for clindamycin. Furthermore, an inhibitory effect was revealed for cultures with an initial parasitemia of either 10 or 7% for Babesia bovis or Babesia bigemina , respectively. The three inhibitors caused immediate death of Babesia bovis and Babesia equi . The inhibitory effects of ciprofloxacin, thiostrepton, and rifampin were confirmed by reverse transcription-PCR. Thiostrepton at a dose of 500 mg/kg of body weight resulted in 77.5% inhibition of Babesia microti growth in BALB/c mice. These results implicate the apicoplast as a potential chemotherapeutic target for babesiosis.

The crystal quality and emission characteristics of InGaN-based laser diodes (LDs) with lattice-matched quaternary InAlGaN cladding layers on novel semi-polar {2 0 2 1} plane GaN substrates were investigated. Highly homogeneous InGaN quantum wells (QWs) with a suppressed piezoelectric field can be realized on the {2 0 2 1} plane even in the green spectral region. Optical polarization measurements revealed that [1 0 1 4] oriented stripes are advantageous for LDs on {2 0 2 1} planes. Gain-guided LDs on the novel (2 0 2 1) plane exhibited the longest lasing wavelength at 533.6 nm under pulsed operation. Continuous-wave (cw) operation at the lasing wavelength of 523.3 nm at 115 mA was also demonstrated. The I th , J th , V th , and the slope efficiency were 110 mA, 9.2 kA/cm 2 , 7.4 V, and 0.04 W/A, respectively. These results indicate that the green LDs on semi-polar {2 0 2 1} plane GaN substrates are promising candidates for laser display applications.

The main objective of this paper is to define Γ-functions Γ[χ](v) with characters χ and study their properties. To this end, we ought to introduce L-functions [Formula: see text] of Hurwitz type. We prove that [Formula: see text] holds, which combines the theory at "s = 0" and the theory at "s = 1".

We obtain a “Kronecker limit formula” for the Epstein zeta function. This is done by introducing a generalized gamma function attached to the Epstein zeta function. The methods involve generalizing ideas of Shintani and Stark. We first show that a generalized gamma function appears as the value at s = 0 of the first derivative of the associated Epstein zeta function. Then this is used to yield Kronecker's limit formula and its “ s = 0 ”-version.

InGaN light-emitting diodes (LEDs) on GaN substrates with low threading dislocation densities (TDDs) were fabricated, and the characteristics of the LEDs were compared with those on sapphire substrates. LEDs with 3 nm-thick-quantum-wells (QWs) grown on GaN as well as on sapphire substrates showed a decrease of the external quantum efficiency (EQE) with increasing forward current, indicating that carrier localization is in play in both cases. The decrease in the EQE was, however, suppressed in LEDs grown on GaN substrates by adopting thicker QWs. The LED with 5 nm-thick-QWs on GaN substrate mounted p-side down and molded with epoxy showed EQE as high as 26% at 125 A/cm 2 . Cathodo luminescence (CL) observations revealed the formation of dark areas related to TDDs, and the dark areas deteriorated the EQE of the LED on the sapphire substrate.

A physical analytic formula based on Stochastic Differential Equation was successfully developed to describe intrinsic ReRAM variation. The formula was proved useful for projecting scaled ReRAM memory window and resistance distribution after long-term retention, verified by testing 40 nm 2-Mbit ReRAM. The formula also centered on practical and quantitative filament characterization.

We investigate, for the first time, the expansion of resistive random access memory (ReRAM) conductive filaments during pulse cycles, which may cause retention failure after cycling endurance. We find that filament size becomes larger gradually because of oxygen diffusion from the region surrounding a filament during reset operations. To achieve long-term use of ReRAM while avoiding filament expansion, it is the key to control both an electric power and a pulsewidth input at a switching operation. We successfully demonstrate good data retention even after endurance of 100-k cycles with an optimized reset pulse.

The role of N-related point defects in the degradation process of ZnSe-based white light-emitting diodes under operation was investigated. The generation rate of microscopic dark spots, which do not correspond to the original stacking faults or threading dislocations in the epilayer, was found to correspond to the initial concentration of the N-related deep-level H0 (ET−Ev=0.8±0.2eV) in the p-ZnMgSSe layer. Devices with high initial H0 concentrations resulting from thermal treatments, at the same time, showed a drastic reduction in their net acceptor concentrations. The origin of this effect is believed to be due to the deactivation of the N acceptor, rather than the hole-trapping effect of the H0 center.

We have demonstrated ZnSe-based white LEDs with longer lifetime over 10,000 h at 14.5 A/cm 2 by introducing an i-ZnMgBeSe/p-ZnMgSe double cladding structure, which combined a very thin i-ZnMgBeSe layer for suppressing electron overflow and p-ZnMgSSe for efficient p-type carrier concentration. By adopting the double cladding layer instead of the conventional p-ZnMgSSe cladding layer, rapid degradation is suppressed. The device simulation and the temperature dependence of optical power showed that the i-ZnMgBeSe layer played the main role in increasing electron confinement. Our reliability test results indicate that the suppression of the electron overflow is essential to obtain long lifetime acceptable for truly practical use.

The degradation mechanism responsible for limiting the lifetime of ZnSe-based white light-emitting diodes was studied. A systematic investigation on the effects of pre-existing stacking faults and threading dislocations, along with point defects in the epitaxial layers was conducted by monitoring their behavior during an aging experiment. Our experimental results, in conjunction with numerical calculations performed on degraded device structures, suggest that the deterioration of the internal quantum efficiency owing to the reduction of the net acceptor concentration in the p-ZnMgSSe cladding layer is responsible for the decline of the optical output power. The reduction in the free hole concentration has an effect of increasing the electron leakage current, leading to a decrease in the carrier injection efficiency. It is also proposed that the carrier depletion effect in the p-cladding layer is due to self-compensation resulting from the increase in the concentration of N-related deep donors.

This paper presents slow mode degradation mechanism of ZnSe-based white LEDs, which is induced by point defect. The white LEDs are very high quality devices, of which the optical power at a forward current of 20 mA is 8.3 mW and the luminous efficiency is 28 lm/W, which is comparable to GaN-based white LEDs in the market. It is proven that microscopic point defects in the devices, detected as deep hole traps of the H1 center (E v + 0.6 eV) and H0 center (E v + 0.8 eV) in p-type ZnMgSSe cladding layer, are responsible for the slow-mode degradation. These point defects, related to nitrogen complex centers, are very electrically active under device operation. An important insight of the H0 center are found that the mobility of the defect is extremely high, and then it induces marked interaction with macroscopic defects.

Development of a reliable platform and workflow to detect and capture a small number of mutation-bearing circulating tumor cells (CTCs) from a blood sample is necessary for the development of noninvasive cancer diagnosis. In this preclinical study, we aimed to develop a capture system for molecular characterization of single CTCs based on high-density dielectrophoretic microwell array technology. Spike-in experiments using lung cancer cell lines were conducted. The microwell array was used to capture spiked cancer cells, and captured single cells were subjected to whole genome amplification followed by sequencing. A high detection rate (70.2%–90.0%) and excellent linear performance (R2 = 0.8189–0.9999) were noted between the observed and expected numbers of tumor cells. The detection rate was markedly higher than that obtained using the CellSearch system in a blinded manner, suggesting the superior sensitivity of our system in detecting EpCAM− tumor cells. Isolation of single captured tumor cells, followed by detection of EGFR mutations, was achieved using Sanger sequencing. Using a microwell array, we established an efficient and convenient platform for the capture and characterization of single CTCs. The results of a proof-of-principle preclinical study indicated that this platform has potential for the molecular characterization of captured CTCs from patients.

Gasless laparoscopic hepatic resection with a 5-cm minilaparotomy was performed in 10 cirrhotic patients with small liver tumors. To maintain good visualization and working space during hepatic resections, we developed a simple retraction system. Mean operative time and blood loss were 291 minutes and 249 mL, respectively. No blood transfusion was required during the operations. No serious complications occurred such as gas embolism. Our laparoscopic procedures had various advantages. Blood, smoke, and water vapor could be aspirated by suction without disturbance of the visual field. There was no risk of gas embolism. It was possible to use conventional instruments through the ports or the wound made by a minilaparotomy. Hemostasis therefore could be performed easily. The procedure could be applicable to cirrhotic patients with some complications. This laparoscopic procedure is recommended for patients with small HCCs associated with liver cirrhosis who are not candidates for major hepatectomy.

A quantitative 3D conductive filament model for ReRAM is developed based on a hopping percolation theory without any fitting parameter. According to the theory, the dimensions and oxygen vacancy concentration of the conductive filament are functions of the resistance distribution. We perform Monte Carlo simulations for calculating the resistance distribution and derive the physical parameters for quantitative simulation based on the relation between resistivity and the oxygen concentration of TaO x . The dimensions and oxygen vacancy concentration are estimated by simulating the resistance distribution. The estimated conductive filament diameters are corroborated by EBAC and TEM observations.

Taking advantage of electron hopping between oxygen vacancies in filaments, ReRAM switching is caused by oxygen vacancy migration. We have developed an oxygen diffusion retention model, based on this switching mechanism, for both typical bits and outlier bits. Degradation of resistance of typical bits is due to the oxygen vacancy profile in the filament changing during oxygen diffusion, and the retention failure of outlier bits is caused by the critical percolation path being broken within the filament during oxygen diffusion.

Nine cirrhotic patients with liver tumors underwent a gasless laparoscopic hepatic resection with a 5 cm minilaparotomy. To maintain the good visualization and working space during hepatic resections, we developed a simple retraction system. Tumors located in segment II through VI of the liver could be treated by the laparoscopic procedure. In three of the nine patients, laparoscopic microwave coagulation therapy was added for each HCC tumors that were detected by intraoperative sonography. No blood transfusion was necessary during the operations. No serious complications such as air embolism occurred. The procedure was also applicable to cirrhotic patients with some complications. The good indication of the laparoscopic procedure is for the patients with small HCCs associated with liver cirrhosis, who are not candidates for radical hepatic resection.

Vertical heterojunction field-effect transistors (VHFETs) utilizing re-grown AlGaN/GaN two-dimensional electron gas (2DEG) channels on free-standing GaN substrates have been developed. The VHFETs exhibited a specific on-resistance (RonA) of 7.6 mΩcm2 at a threshold voltage (Vth) of -1.1 V and a breakdown voltage (VB) of 672 V. The breakdown voltage and the figure of merit (VB2/RonA) are the highest among those of the GaN-based vertical transistors ever reported. It was demonstrated that the threshold voltage can be controlled by the thickness of AlGaN layers and Al concentration. A normally-off operation was achieved with a 10-nm-thick Al0.2Ga0.8N layer. The possibility that VHFET with smaller current collapse phenomena than planar HEMT was revealed (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The first phosphor-free white LED based on II–IV compound materials is demonstrated. Our device utilizes a phenomenon unique to ZnSe homoepitaxy, where a portion of the main greenish-blue emission from the active layer of a pn junction diode is absorbed by the conductive substrate which in turn gives off an intense broad-band yellow emission centered around 585 nm by photoluminescence. These two emission bands combine to give a spectrum which appears white to the naked eye. A typical ZnSe-based white LED lamp exhibits a color temperature of approximately 3400 K with a CRI (color rendering index) of 68. The optical output power and operating voltage of such a device at a forward current of 20 mA is 2.0 mW and 2.7 V, respectively. The luminous efficiency estimated from these results is 10.4l m/W, which is comparable to the incandescent lamp as well as the commercial InGaN-based white LED. Device lifetimes (half-life) have exceeded 800 h at 20°C.

Radical polymerizations of N-(tricyclo[3.3.1.13,7]decane-1-yl)4-vinylbenzylamine (Ad0) and N-(tricyclo[3.3.1.13,7]decane-1-yl-methyl)4-vinylbenzylamine (Ad1) were conducted in bulk under nitrogen. The polymerizations of Ad0 and Ad1 proceeded at the vinyl groups to give polymers with adamantane amino derivatives as pendant groups. The polymerization of Ad0 gave the polymers without any crosslinked product, although a partially or completely crosslinked polymer was obtained from the polymerization of Ad1 at high temperature. Thermal stability of poly(Ad0) and poly(Ad1) was excellent, and the stability of poly(Ad1) was much higher than that of poly(Ad0). The copolymerizations of Ad0 and Ad1 with styrene and methyl methacrylate (MMA) were also performed by 2,2′-azobis(isobutyronitrile) (AIBN) at 80°C. The copolymers had similar feed ratios of monomers to styrene or MMA.

Our uncommon experience with a case of accessory breast cancer is described. A 67-year-old woman was seen at the hospital because of a left axillary tumor. An excisional biopsy of the tumor revealed medullary carcinoma with mammary gland, without connection to the proper mammary gland. There was no other primary lesion in general exploration and clinical findings also offered a suspicion of accessory breast cancer. A wide local resection with lymph nodes dissection level III was carried out. She is doing well without any evidence of recurrence, as of 10 months after the operation.

Characteristics and their origin of a conductive filament in TaOx ReRAM are investigated. The results of systematic experimentation demonstrate that the formation of a small conductive filament with high density of oxygen vacancies, achieved by controlling the oxygen content of the resistance-switching material and forming/set current, is the key to achieving low-current switching combined with long retention.

Resistive RAM (ReRAM) has been recently developed for applications that require higher speed and lower voltage than Flash memory is able to provide. One of the applications is micro-controller units (MCUs) or SoCs with several megabits of embedded ReRAM. Another is solid-state drives (SSDs) where a combination of higher-density ReRAM and NAND flash memory would achieve high-performance and high-reliability storage [1], suitable for server applications for future cloud computing. ReRAM is attractive for several reasons. First, it operates at high speed and low voltage. Second, it enables high density due to the simple structure of the resistive element (RE) [2]. Third, it is immune to external environment such as magnetic fields or radiation, since the resistive switching is based on the redox reaction [3].

double Y型マイクロリアクタによる水と有機溶媒の分離について検討した. 粘性率がほぼ等しい水とシクロヘキサンを汎用のリアクタに等しい流速で供給すると, 目視的には層流が観察されたが, 排出液は両者の混合物となった. これは, ガラスチャンネル内壁が親水性であるためと考えられる. そこで,チャンネル中央に等間隔で不連続な仕切壁を設けた破線状ガイドライン構造としたところ, 分離能は飛躍的に向上した.

We demonstrate for the first time that the density of oxygen vacancy in a conductive filament plays a key role in ensuring data retention. We achieve very good retention results up to 100 hours at 150°C even under the low current operation due to the scaling of conductive filament size while retaining sufficiently high density of oxygen vacancy.

A retention model for both the high resistance state and low resistance state of the bipolar ReRAM is developed. Degradation of resistance is caused by the oxygen vacancy profile in filament changing due to oxygen diffusion.

A new oxygen diffusion reliability model for a high-density bipolar ReRAM is developed based on hopping conduction in filaments, which allows statistical predication of activation energy. The filament in the active cells is confirmed by EBAC and TEM directly for the first time. With optimized filament size, a 256-kbit ReRAM with long-term retention exceeding 10 years at 85°C is successfully demonstrated.

531 nm InGaN-based true green LDs on semi-polar {2021} GaN substrates were demonstrated under pulsed operation. 520 nm cw lasing was also achieved by adopting a ridge-waveguide structure. The advantages of this particular semi-polar plane for green LDs will be discussed in the talk.

The nucleophilic addition of organotitanium reagents to α-keto amides derived from (2R,5R)-trans-2,5-bis(t-butyldimethylsiloxymethylsiloxymethyl)pyrrolidine [(R,R)-BTBSP] afforded the corresponding α-hydroxy amides with very high diastereofacial selectivity.

Two hundred and eighty-seven patients with bleeding gastroduodenal ulcer who were admitted with the chief complaints of hematemesis and/or melena were clinicopathologically studied. The operation was performed in 155 (54.0%) patients. Bleeding rates were 78.0% in UL-II, 44.0% in UL-III, and 47.0 in UL-IV. The rates needed emergency operation were 76.5% in UL-II, 42.9% in UL-III and 46.6% in UL-IV. Both bleeding and emergency operation rates were higher in UL-II cases. From an examination of the diameter of exposed vessels in vascular stump-positive cases, the inner-to-outer diameter ratio of the vessels was significantly smaller in UL-II (0.074) compared to UL-IV (0.125) cases. This fact indicates that UL-II cases less frequently associate with intimal hypertrophy, and once the vessels are broken, thrombosis is hard to be formed, accordingly more efforts being demonded for its hemostasis.