Numerical and analytical investigations for the SOI LDMOS with alternated high-k dielectric and step doped silicon pillars

This paper presents a new silicon-on-insulator(SOI) lateral-double-diffused metal-oxide-semiconductor transistor(LDMOST) device with alternated high-k dielectric and step doped silicon pillars(HKSD device). Due to the modulation of step doping technology and high-k dielectric on the electric field and doped profile of each zone, the HKSD device shows a greater performance. The analytical models of the potential, electric field, optimal breakdown voltage, and optimal doped profile are derived. The analytical results and the simulated results are basically consistent, which confirms the proposed model suitable for the HKSD device. The potential and electric field modulation mechanism are investigated based on the simulation and analytical models. Furthermore, the influence of the parameters on the breakdown voltage(BV) and specific on-resistance(R_(on,sp)) are obtained. The results indicate that the HKSD device has a higher BV and lower R_(on,sp) compared to the SD device and HK device.

Influence of copper element distribution and speciation on the color of Chinese underglaze copper-red porcelain in the Yuan dynasty

A shard of Chinese underglaze copper-red porcelain from the Yuan dynasty (AD 1271–1368) made in the Jingdezhen kiln was measured by synchrotron radiation- induced X-ray fluorescence mapping and X-ray absorption near-edge spectroscopy to investigate the influence of copper element distribution and speciation on the color of porcelain. In black-colored region, copper accumulates at the interface between the body and glaze layers with metallic copper particles as the main speciation. In contrast, Cu is irregularly distributed in the red-colored region with multi-valence speciation. The differences in Cu distribution and speciation in black- and red-colored regions indicate that they are the main factors influencing the different colors of copper-red underglaze porcelain.

NF-κB: A novel therapeutic pathway for gastroesophageal reflux disease?

Although gastroesophageal reflux disease(GERD),a common chronic disease in clinical practice,has been widely studied,its potential adverse impact on patients is still a significant clinical concern.It is necessary to understand the pathogenesis of the disease and choose appropriate treatment according to its mechanism.The pathogenesis of GERD is diverse and complex.As the traditional treatment methods are expensive and ineffective in alleviating symptoms in some patients,new treatment options need to be explored.Our previous study suggested that the activation of nuclear factor-kappa beta(NF-κB)in esophageal mucosa may be related to the injury of epithelial barrier function caused by reflux.Based on the literature and our previous study results,it is speculated that inhibition of NF-κB activation may block the insult of GERD on the esophageal mucosal barrier.NF-κB may play an important role in the development of GERD.This article reviews the pathogenesis of GERD and the relationship between NF-κB and GERD,in order to provide new strategies for the treatment of GERD.

A 4×4 metal-semiconductor-metal rectangular deep-ultraviolet detector array of Ga_(2)O_(3)photoconductor with high photo response

A 4×4 beta-phase gallium oxide(β-Ga_(2)O_(3))deep-ultraviolet(DUV)rectangular 10-fingers interdigital metalsemiconductor-metal(MSM)photodetector array of high photo responsivity is introduced.The Ga2O_(3)thin film is prepared through the metalorganic chemical vapor deposition technique,then used to construct the photodetector array via photolithography,lift-off,and ion beam sputtering methods.The one photodetector cell shows dark current of 1.94 p A,phototo-dark current ratio of 6×10_(7),photo responsivity of 634.15 A·W^(-1),specific detectivity of 5.93×1011cm·Hz1/2·W^(-1)(Jones),external quantum efficiency of 310000%,and linear dynamic region of 108.94 d B,indicating high performances for DUV photo detection.Furthermore,the 16-cell photodetector array displays uniform performances with decent deviation of 19.6%for photo responsivity.

A self-powered ultraviolet photodetector based on a Ga_(2)O_(3)/Bi_(2)WO_(6)heterojunction with low noise and stable photoresponse

A self-powered solar-blind ultraviolet(UV)photodetector(PD)was successfully constructed on a Ga_(2)O_(3)/Bi_(2)WO_(6)heterojunction,which was fabricated by spin-coating the hydrothermally grown Bi_(2)WO_(6)onto MOCVD-grown Ga_(2)O_(3)film.The results show that a typical type-I heterojunction is formed at the interface of the Ga_(2)O_(3)film and clustered Bi_(2)WO_(6),which demonstrates a distinct photovoltaic effect with an open-circuit voltage of 0.18 V under the irradiation of 254 nm UV light.Moreover,the Ga_(2)O_(3)/Bi_(2)WO_(6)PD displays excellent photodetection performance with an ultra-low dark current of~6 fA,and a high light-to-dark current ratio(PDCR)of 3.5 x 10^(4)in self-powered mode(0 V),as well as a best responsivity result of 2.21 mA/W in power supply mode(5 V).Furthermore,the PD possesses a stable and fast response speed under different light intensities and voltages.At zero voltage,the PD exhibits a fast rise time of 132 ms and 162 ms,as well as a quick decay time of 69 ms and 522 ms,respectively.In general,the newly attempted Ga_(2)O_(3)/Bi_(2)WO_(6)heterojunction may become a potential candidate for the realization of self-powered and high-performance UV photodetectors.

A broadband self-powered UV photodetector of aβ-Ga2O3/γ-CuI p–n junction

The symmetric Ti/Au bi-layer point electrodes have been successfully patterned on theβ-Ga;O;films which are prepared by metal–organic chemical vapor deposition(MOCVD)and theγ-Cu I films which are prepared by spin-coating.The fabricated heterojunction has a large open circuit voltage(Voc)of 0.69 V,desired for achieving self-powered operation of a photodetector.Irradiated by 254-nm ultraviolet(UV)light,when the bias voltage is-5 V,the dark current(Idark)of the device is 0.47 p A,the photocurrent(Iphoto)is-50.93 n A,and the photo-to-dark current ratio(Iphoto/Idark)reaches about 1.08×10;.The device has a stable and fast response speed in different wavelengths,the rise time(τr)and decay time(τd)are 0.762 s and 1.741 s under 254-nm UV light illumination,respectively.While theτr andτd are 10.709 s and7.241 s under 365-nm UV light illumination,respectively.The time-dependent(I–t)response(photocurrent in the order of10-10 A)can be clearly distinguished at a small light intensity of 1μW·cm;.The internal physical mechanism affecting the device performances is discussed by the band diagram and charge carrier transfer theory.

Lactation mastitis: Promising alternative indicators for early diagnosis

Although lactation mastitis(LM)has been extensively researched,the incidence rate of LM remains a salient clinical problem.To reduce this incidence rate and achieve a better prognosis,early and specific quantitative indicators are particularly important.It has been found that milk electrolyte concentrations(chloride,potassium,and sodium)and electrical conductivity(EC)significantly change in the early stages of LM in an animal model.Several studies have evaluated EC for the detection of subclinical mastitis in cows.EC,chloride,and sodium content of milk were more accurate for predicting infection status than were other variables.In the early stages of LM,lactic sodium,chloride,and EC increase,but potassium decreases.However,these indicators have not been reported in the diagnosis of LM in humans.This review summarizes the pathogenesis and the mechanism of LM in terms of milk electrolyte concentration and EC,and aim to provide new ideas for the detection of sub-clinical mastitis in humans.

The growth and expansive applications of amorphous Ga_(2)O_(3)

As a promising ultra-wide bandgap semiconductor material,gallium oxide(Ga_(2)O_(3))is attracting extensive attention of researchers due to its feasible growth process,appropriate bandgap of 4.4 e V-5.3 e V allowing for deep-ultraviolet(deepUV)detection,good physical and chemical stability,high breakdown field strength and electron mobility,etc.Different from the strict processes for controllable crystalline Ga_(2)O_(3)(usually refer to as stable monoclinicβ-Ga_(2)O_(3)),amorphous Ga_(2)O_(3)(a-Ga_(2)O_(3))film can be prepared uniformly at low temperature on a large-area deposition substrate,suggesting great advantages such as low manufacturing cost and excellent flexibility,dispensing with high-temperature and high vacuum techniques.Thus,a-Ga_(2)O_(3)extremely facilitates important applications in various applied fields.Therefore,in this concise review,we summarize several major deposition methods for a-Ga_(2)O_(3)films,of which the characteristics are discussed.Additionally,potential methods to optimize the film properties are proposed by right of the inspiration from some recent studies.Subsequently,the applications of a-Ga_(2)O_(3)thin films,e.g.,in photodetectors,resistive random access memories(RRAMs)and gas sensors,are represented with a fruitful discussion of their structures and operating mechanisms.

聚降冰片烯/微晶蜡复合材料形状记忆性能的研究

以聚降冰片烯树脂(PNB)为基体,通过改变微晶蜡(MW)的填充含量制备PNB/MW复合材料,利用偏光显微镜、示差扫描量热仪(DSC)、动态力学分析(DMA)与万能电子拉伸试验机等测试手段,研究PNB/MW两相结构与基本性能,同时采用DMA-Q800测试复合材料的二重形状记忆及可逆塑性形状记忆性能,并与填充同等含量的环保芳烃油(TDAE)的PNB进行对比.结果表明,微晶蜡可以调节PNB材料的玻璃化转变温度接近于室温,有利于室温下的可逆塑性形状记忆,且其无污染,可以代替TDAE增塑油改善PNB的加工;PNB/MW复合材料物理机械性能良好,200%以上的断裂伸长率提供了较大的形变范围,有利于材料的变形与恢复;微晶蜡较宽的固-液转变可以作为可逆相,使恢复过程温和可控;固态微晶蜡阻碍PNB链段运动,提高可逆塑性的形状固定率,微晶蜡含量越多,固定效果越明显,PNB/MW50展现出优异的二重及可逆塑性形状记忆性能.

聚降冰片烯可逆塑性形状记忆关键影响因素的研究

以聚降冰片烯(PNB)为基体,添加不同份数的环保芳烃油制备低充油PNB材料,通过示差扫描量热法(DSC)、万能电子拉伸试验机、动态力学分析(DMA)等研究了不同增塑油含量、变形温度、松弛时间等因素对PNB材料可逆塑性形状记忆性能的影响.结果表明,增塑油可连续调节PNB的Tg并使其维持在室温附近,有利于室温下可逆塑性形变;当变形温度低于材料玻璃化转变起始温度2℃时,这时材料变形耗能最低、分子链运动活化能较高,撤除外力后分子链运动受限制,因此固定率较高;而变形温度对材料恢复率影响较小,由于PNB具有超高分子量,当驱动温度远高于其玻璃化转变温度时,分子链熵值增大,产生较大的熵弹恢复力,因此恢复率均高于95.0%,材料具有优异的可逆塑性形状记忆性能;另外,延长松弛时间也可在一定程度上提高材料的形状固定率.