semiconductor

半导体
  • 文章类型: Journal Article
    在半导体工业中使用了大量的质量流量控制器(MFC)。为了稳定的供应,需要一种高效的MFC生产方法。比例积分(PI)控制的增益调节以实现设定流量对于有效的批量生产是必不可少的。调整增益以满足阶跃响应波形中的响应时间和过调量的评估指标所需的规格。特别是对于基于压力的MFC的情况,调谐是复杂的。在本文中,我们提出了一种使用高斯混合模型(GMM)和适用于基于压力的MFC生产的直接反分析进行PI增益调整的简单方法。MFC的标准单元的增益和评估指数之间的关系被建模为GMM。直接反分析计算标准和测试单元之间的差异。在假设差异可以通过简单的移位来补偿的情况下,搜索可能满足测试单元规格的增益。我们将该方法应用于七个测试单元。结果表明,所有测试单元的增益仅在几次迭代中被调整,其数量远小于传统的手动调整方法。也没有不可调的装置.
    A vast number of mass flow controllers (MFCs) are used in semiconductor industry. For the stable supply, an efficient production method of MFC is required. The gain tuning of the proportional-integral (PI) control to realize a setting flow rate is essential for efficient mass production. The gains are tuned to meet the specifications required for evaluation indices of response time and overshoot amount in a step response waveform. The tuning is complicated especially for the case of pressure-based MFCs. In this paper, we propose a simple method for the PI gain tuning using the Gaussian mixture model (GMM) and the direct inverse analysis applicable to the pressure-based MFCs\' production. The relationship between the gains and evaluation indices for a standard unit of the MFC is modeled as the GMM. The direct inverse analysis calculates the difference between the standard and a test unit. Under the assumption that the difference can be compensated by a simple shift, gains likely to meet the specifications for the test unit are searched. We applied the method to seven test units. The result showed that the gains of all the test units were tuned within only a few iterations whose numbers were much less than the conventional manual tuning method, and there was no untunable unit.
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  • 文章类型: Journal Article
    掺杂窄间隙半导体是设计高效热电材料的成熟方法。半导体半Heusler(HH)和全Heusler(FH)化合物在热电领域引起了人们的极大兴趣,然而,优秀候选人的数量仍然相对较少。最近表明,填补空缺的方法是扩大休斯勒家族的可行策略。这里,一系列接近半导体的Heuslers,TiFexCuySb,从理论上设计和实验上合成了符合Slater-Pauling电子计数规则的成分连续体。这些材料中空位位置的随机和不完全占据会不断变化的电导率,范围从终点TiFe0.67Cu0.33Sb中具有低载流子浓度的良好半导体到化学计量为TiFe1.00Cu0.20Sb的重掺杂p型半导体。在中间化合物TiFe0.80Cu0.28Sb中实验观察到最佳的热电性能,在923K达到0.87的峰值品质因数。这些发现表明,填充空位的Heusler化合物为开发先进的热电材料提供了大量机会。
    Doping narrow-gap semiconductors is a well-established approach for designing efficient thermoelectric materials. Semiconducting half-Heusler (HH) and full-Heusler (FH) compounds have garnered significant interest within the thermoelectric field, yet the number of exceptional candidates remains relatively small. It is recently shown that the vacancy-filling approach is a viable strategy for expanding the Heusler family. Here, a range of near-semiconducting Heuslers, TiFexCuySb, creating a composition continuum that adheres to the Slater-Pauling electron counting rule are theoretically designed and experimentally synthesized. The stochastic and incomplete occupation of vacancy sites within these materials imparts continuously changing electrical conductivities, ranging from a good semiconductor with low carrier concentration in the endpoint TiFe0.67Cu0.33Sb to a heavily doped p-type semiconductor with a stoichiometry of TiFe1.00Cu0.20Sb. The optimal thermoelectric performance is experimentally observed in the intermediate compound TiFe0.80Cu0.28Sb, achieving a peak figure of merit of 0.87 at 923 K. These findings demonstrate that vacancy-filling Heusler compounds offer substantial opportunities for developing advanced thermoelectric materials.
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  • 文章类型: Journal Article
    由于其环境友好和可持续的特性,光催化是解决全球能源短缺和环境问题的最重要方法。实现高效光催化的关键在于开发高效、化学稳定性好的催化剂。在各种光催化剂中,金属有机骨架(MOFs)衍生的中空结构材料基于更多的活性位点等优点,在光催化中引起了越来越多的关注,强烈的光吸收,有效转移pho诱导的电荷,出色的稳定性,高导电性,和更好的生物相容性。具体来说,MOFs衍生的中空结构材料广泛用于光催化CO2还原(CO2RR),析氢(HER),固氮(NRR),降解,和其他反应。这篇评论从MOFs的发展故事开始,MOFs衍生的中空材料的常用合成策略,并详细介绍了光催化在各种应用领域的最新研究进展。最终,并对MOFs衍生的中空结构材料在实际光催化应用中面临的挑战进行了展望。这篇综述对于开发更适用和有效的MOFs衍生的中空结构光催化剂具有巨大的潜力。
    Photocatalysis is a most important approach to addressing global energy shortages and environmental issues due to its environmentally friendly and sustainable properties. The key to realizing efficient photocatalysis relies on developing appropriate catalysts with high efficiency and chemical stability. Among various photocatalysts, Metal-organic frameworks (MOFs)-derived hollow-structured materials have drawn increased attention in photocatalysis based on advantages like more active sites, strong light absorption, efficient transfer of pho-induced charges, excellent stability, high electrical conductivity, and better biocompatibility. Specifically, MOFs-derived hollow-structured materials are widely utilized in photocatalytic CO2 reduction (CO2RR), hydrogen evolution (HER), nitrogen fixation (NRR), degradation, and other reactions. This review starts with the development story of MOFs, the commonly adopted synthesis strategies of MOFs-derived hollow materials, and the latest research progress in various photocatalytic applications are also introduced in detail. Ultimately, the challenges of MOFs-derived hollow-structured materials in practical photocatalytic applications are also prospected. This review holds great potential for developing more applicable and efficient MOFs-derived hollow-structured photocatalysts.
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  • 文章类型: Journal Article
    本研究使用原子探针断层扫描(APT)研究了表面电场对硼(B)注入硅(Si)的定量精度的影响。使用Si电荷状态比(CSR(Si)=Si2+/Si+)作为分析期间平均顶点电场的间接测量。对于一系列电场,通过APT确定的总植入剂量和深度剖面形状的准确性与美国国家标准技术研究所标准参考材料2137进行评估。还检查了检测到的B的径向(非)均匀性。在较高的表面电场(即,更大的企业社会责任(Si)),确定的B剂量收敛于认证剂量。此外,深度分布的形状倾向于通过二次离子质谱得出的形状。这种改进与更均匀的径向B分布相吻合,解吸图证明了这一点。相比之下,对于较低的表面电场(即,较低的企业社会责任(Si)),B剂量被大大低估了,深度剖面是人为拉伸的。解吸图还表明位于检测器中心周围的高度不均匀的B发射,这被认为是样品尖端上的B表面迁移的伪影。为了使用APT对半导体器件进行常规调查,这些结果说明了量化伪影的潜在来源及其在不同操作条件下的严重程度,从而为准确和可重复的测量提供最佳实践的途径。
    This study investigates the impact of the surface electric field on the quantification accuracy of boron (B) implanted silicon (Si) using atom probe tomography (APT). The Si Charge-State Ratio (CSR(Si) = Si2+/Si+) was used as an indirect measure of the average apex electric field during analysis. For a range of electric fields, the accuracy of the total implanted dose and the depth profile shape determined by APT was evaluated against the National Institute of Standards and Technology Standard Reference Material 2137. The radial (non-)uniformity of the detected B was also examined. At a higher surface electric field (i.e., a greater CSR(Si)), the determined B dose converges on the certified dose. Additionally, the depth profile shape tends towards that derived by secondary ion mass spectrometry. This improvement coincides with a more uniform radial B distribution, evidenced by desorption maps. In contrast, for lower surface electric fields (i.e., a lower CSR(Si)), the B dose is significantly underestimated, and the depth profile is artificially stretched. The desorption maps also indicate a highly inhomogeneous B emission localized around the center of the detector, which is believed to be an artifact of B surface migration on the tip of the sample. For the purposes of routine investigations of semiconductor devices using APT, these results illustrate the potential origin of quantification artifacts and their severity at different operating conditions, thus providing pathways towards best practices for accurate and repeatable measurements.
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  • 文章类型: Journal Article
    二维(2D)铁磁半导体(FMSC)为纳米器件中量子信息技术的发展提供了理想的平台。然而,许多开发的2DFM材料呈现出非常低的居里温度(TC),大大限制了它们在自旋电子器件中的应用。在这项工作中,我们预测了两种稳定的二维过渡金属硫族化物,V3Se3X2(X=S,Te)单层,通过使用第一原理计算。我们的结果表明,V3Se3Te2单层是一个强大的双极磁性SC,具有0.53eV的中等带隙,而V3Se3S2是直接带隙FMSC,带隙为0.59eV。有趣的是,由于V-S/Se/Te-V超交换相互作用,两个单层的铁磁性都是稳健的,TC约为406K和301K,分别。施加双轴应变,在双轴拉伸应变的5%和3%时,显示了FMSC到反铁磁(AFM)SC的转变。此外,他们的高机械,动态,通过声子色散计算和从头算分子动力学(AIMD)计算进一步验证了热稳定性。他们出色的属性渲染V3Se3Y2(Y=S,Te)单层有望作为2DFMSC用于广泛的应用。
    Two-dimensional (2D) ferromagnetic semiconductors (FM SCs) provide an ideal platform for the development of quantum information technology in nanoscale devices. However, many developed 2D FM materials present a very low Curie temperature (TC), greatly limiting their application in spintronic devices. In this work, we predict two stable 2D transition metal chalcogenides, V3Se3X2 (X = S, Te) monolayers, by using first-principles calculations. Our results show that the V3Se3Te2 monolayer is a robust bipolar magnetic SC with a moderate bandgap of 0.53 eV, while V3Se3S2 is a direct band-gap FM SC with a bandgap of 0.59 eV. Interestingly, the ferromagnetisms of both monolayers are robust due to the V-S/Se/Te-V superexchange interaction, and TCs are about 406 K and 301 K, respectively. Applying biaxial strains, the FM SC to antiferromagnetic (AFM) SC transition is revealed at 5% and 3% of biaxial tensile strain. In addition, their high mechanical, dynamical, and thermal stabilities are further verified by phonon dispersion calculations and ab initio molecular dynamics (AIMD) calculations. Their outstanding attributes render the V3Se3Y2 (Y = S, Te) monolayers promising candidates as 2D FM SCs for a wide range of applications.
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  • 文章类型: Journal Article
    简介:软组织中的许多外科手术都是使用二极管激光器进行的。这项研究旨在评估使用810和980nm二极管激光器进行第二阶段牙科植入手术后的温度升高和疼痛。方法:本临床试验对24个骨整合牙种植体进行,随机分为810nm和980nm二极管激光两组。每组的温度上升是在激光发现后测量的,15分钟后用热电偶测量的,与牙龈组织的基线温度相比。在术后24小时还通过使用视觉模拟量表测量疼痛水平。数据通过方差分析进行分析,Tukey\'stest,和t检验(α=0.05)。结果:通过ANOVA进行的组内比较显示,两组三个时间点之间的组织温度存在显着差异(P<0.0001)。通过Tukey检验的成对比较显示,两组的基线温度(P<0.0001)和发现后15秒的温度显着低于发现后立即的温度(P<0.0001)。980nm激光组的平均组织温度和平均疼痛评分明显高于810nm激光组(P<0.05)。结论:根据研究结果,使用980nm激光的温升高于810nm激光。使用810nm二极管激光与24小时后较低的温度升高和显着降低的疼痛评分相关。
    Introduction: Many surgical procedures in a soft tissue are performed using diodes lasers. This study aimed to assess the temperature rise and pain following the use of 810 and 980 nm diode lasers for second-stage dental implant surgery. Methods: This clinical trial was conducted on 24 osseointegrated dental implants that were randomly divided into two groups of 810 nm and 980 nm diode lasers. The temperature rise in each group was measured right after uncovering by the laser and 15 minutes later by a thermocouple, compared with the baseline temperature of gingival tissue. The level of pain was also measured at 24 hours postoperatively by using a visual analog scale. Data were analyzed by ANOVA, Tukey\'s test, and t test (alpha=0.05). Results: Within-group comparisons by ANOVA showed a significant difference in tissue temperature between the three time points in both groups (P<0.0001). Pairwise comparisons by Tukey\'s test showed that the temperature at baseline (P<0.0001) and 15 seconds after uncovering was significantly lower than that immediately after uncovering in both groups (P<0.0001). The mean tissue temperature and the mean pain score in the 980 nm laser group were significantly higher than the corresponding values in the 810 nm laser group (P<0.05). Conclusion: According to the results, temperature rise in the use of the 980 nm laser was higher than the 810 nm laser. The use of 810 nm diode laser was associated with lower temperature rise and significantly lower pain score after 24 hours.
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  • 文章类型: Journal Article
    氟氧化铋(BiOF)是一类具有显著化学稳定性的新兴材料,独特的层状结构和引人注目的能带结构。Bi基半导体材料和还原氧化石墨烯(rGO)由于其广泛的潜在应用而引起了广泛的关注。在这里,我们成功地合成了一种有效的光催化剂,包括BiOF-rGO纳米复合材料与嵌入Ag纳米颗粒使用简单的水热法。合成的纳米复合材料通过傅里叶变换红外光谱进行表征,X射线衍射(XRD)场发射扫描电子显微镜和紫外(UV)-可见光谱。XRD结果表明BiOF的晶体结构,Ag掺杂BiOF和Ag掺杂BiOF-rGO复合材料。光催化活性评估集中在紫外线和阳光照射下亚甲基蓝(MB)和甲基橙(MO)染料的降解。Ag掺杂的BiOF-rGO复合材料表现出显著增强的降解效率,实现MB和MO的61.81%和74.25%的降解,分别,在紫外光照射下300分钟后。相反,纯BiOF对MB和MO的降解率仅为17.63%和48.29%,分别,在类似的条件下。此外,在阳光照射下,Ag掺杂的BiOF-rGO复合材料在300分钟后显示出43.87%的MB去除效率,而纯BiOF在相同条件下仅显示27.47%。这些结果强调了Ag掺杂的BiOF-rGO复合材料作为用于工业废水中有机染料光降解的高效和适应性强的光催化剂的潜力。
    Bismuth oxyfluoride (BiOF) is an emerging class of material with notable chemical stability, unique layered structure and striking energy band structure. Bi-based semiconductor materials and reduced graphene oxides (rGOs) have attracted considerable attention due to their broad spectrum of potential applications. Herein, we successfully synthesised an efficient photocatalyst comprising BiOF-rGO nanocomposites with embedded Ag nanoparticles using a simple hydrothermal method. The synthesised nanocomposites were characterised through Fourier-transform infrared spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy and ultraviolet (UV)-visible spectroscopy. The XRD results indicated the crystalline structures of the BiOF, Ag-doped BiOF and Ag-doped BiOF-rGO composites. Photocatalytic activity assessments focused on the degradation of methylene blue (MB) and methyl orange (MO) dyes under UV-light and sunlight irradiation. The Ag-doped BiOF-rGO composite exhibited significantly enhanced degradation efficiency, achieving 61.81 % and 74.25 % degradation of MB and MO, respectively, after 300 min under UV-light irradiation. On the contrary, pure BiOF demonstrated only 17.63 % and 48.29 % degradation for MB and MO, respectively, under similar conditions. Furthermore, under sunlight irradiation, the Ag-doped BiOF-rGO composite exhibited an MB removal efficiency of 43.87 % after 300 min, whereas pure BiOF showed only 27.47 % under identical conditions. These results underscore the potential of Ag-doped BiOF-rGO composites as highly efficient and adaptable photocatalysts for the photodegradation of organic dyes in industrial wastewater.
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  • 文章类型: Journal Article
    在三(六氟乙酰丙酮)的存在下,四苯并喹二甲烷对四苯并(TSeT)的氧化,DyIII(hfac)3,产生{TSeT1.5}●+[DyIII(hfac)4]-(1)盐的黑色晶体,结合了导电和磁性亚晶格。它包含由部分氧化的TSeT分子组成的一维堆叠(形式平均电荷为2/3)。二聚体和单体可以在这些具有电荷和自旋密度重新分布的堆叠内勾勒出来。二聚体的自旋三重态填充在128K以上,估计的单重态三重态能隙为542K,而位于单体上的自旋显示顺磁性。观察到1的半导体行为,活化能为91meV(通过四探针技术对取向单晶进行测量)。DyIII离子配位[DyIII(hfac)4]-中的四个hact-阴离子,提供D2d对称性。在施加1000Oe的静磁场下,DyIII观察到缓慢的磁弛豫,1是单离子磁体(SIM),自旋反转势垒Ueff=40.2K,磁滞在2K。在EPR中可以看到DyIII和TSeT●顺磁性物种的贡献。DyIII离子很少显示EPR信号,但在1中观察到这样的信号。由于缩小到30K以下而出现,并且在5.4K时g4=6.1871和g5=2.1778。
    The oxidation of tetraselenatetracene (TSeT) by tetracyanoquinodimethane in the presence of dysprosium(III) tris(hexafluoroacetylacetonate), DyIII(hfac)3, produces black crystals of {TSeT1.5}●+[DyIII(hfac)4]- (1) salt, which combines conducting and magnetic sublattices. It contains one-dimensional stacks composed of partially oxidized TSeT molecules (formal averaged charge is +2/3). Dimers and monomers can be outlined within these stacks with charge and spin density redistribution. The spin triplet state of the dimers is populated above 128 K with an estimated singlet-triplet energy gap of 542 K, whereas spins localized on the monomers show paramagnetic behavior. A semiconducting behavior is observed for 1 with the activation energy of 91 meV (measured by the four-probe technique for an oriented single crystal). The DyIII ions coordinate four hfac- anions in [DyIII(hfac)4]-, providing D2d symmetry. Slow magnetic relaxation is observed for DyIII under an applied static magnetic field of 1000 Oe, and 1 is a single-ion magnet (SIM) with spin reversal barrier Ueff = 40.2 K and magnetic hysteresis at 2 K. Contributions from DyIII and TSeT●+ paramagnetic species are seen in EPR. The DyIII ion rarely manifests EPR signals, but such signal is observed in 1. It appears due to narrowing below 30 K and has g4 = 6.1871 and g5 = 2.1778 at 5.4 K.
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  • 文章类型: Journal Article
    这篇综述集中于其中至少一个膦酸酯基团直接连接到杂芳环的化合物的光学性质。此外,这些化合物的合成和其他应用在这项工作中得到了解决。讨论了膦酸酯取代基对所述化合物性能的影响,并与其他非磷取代基进行了比较,特别注意光物理性质,如紫外-可见吸收和发射,荧光量子产率和荧光寿命。考虑到杂原子的存在,收集的材料分为两部分,并对近三十年来有关芳香环中含硫和氮原子的杂芳基膦酸酯的文献进行了综述。
    This review focuses on optical properties of compounds in which at least one phosphonate group is directly attached to a heteroaromatic ring. Additionally, the synthesis and other applications of these compounds are addressed in this work. The influence of the phosphonate substituent on the properties of the described compounds is discussed and compared with other non-phosphorus substituents, with particular attention given to photophysical properties, such as UV-Vis absorption and emission, fluorescence quantum yield and fluorescence lifetime. Considering the presence of heteroatom, the collected material was divided into two parts, and a review of the literature of the last thirty years on heteroaryl phosphonates containing sulfur and nitrogen atoms in the aromatic ring was conducted.
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  • 文章类型: Journal Article
    间充质干细胞在组织修复过程中可以分化为特定的细胞系。使用激光和LED进行光生物调节用于治疗多种合并症,会干扰细胞增殖和活力,除了促进与所采用的物理参数相关的响应。评估和比较激光和LED对间充质细胞的影响,不同的能量剂量和不同的波长,除了生存能力和伤口闭合。来自人脂肪细胞的间充质干细胞用激光照射(能量为0.5J,2J和4J,波长为660nm和830nm),和LED(能量为0.5J,2J和4J,其中长度为630nm和850nm)。通过体外监测病变面积的减少来评估伤口闭合过程。通过用Hoechst和碘化丙啶标记物分析确定活力,活细胞和非活细胞的定量分别使用Shapiro-Wilk检验分析数据分布。使用Levene检验分析均匀性。使用双向ANOVA检验分析所使用的参数之间的比较。将T检验应用于与活力和病变面积相关的数据。对于LED光生物调节,只有630nm波长在24、48和72h中获得了显着结果(p=0,027;p=0,024;p=0,009)。与体外伤口闭合测试相关的结果表明,考虑到接近边缘所花费的时间,使用激光和LED的光生物调节均表现出显著的结果(p<0.05)。考虑到本研究的体外实验条件,可以得出结论,光生物调节的物理参数,比如能量和波长,在间充质干细胞中使用激光或LED,可以在细胞活力和伤口闭合中起潜在的作用。
    Mesenchymal stem cells can differentiate into specific cell lineages in the tissue repair process. Photobiomodulation with laser and LED is used to treat several comorbidities, can interfere in cell proliferation and viability, in addition to promoting responses related to the physical parameters adopted. Evaluate and compare the effects of laser and LED on mesenchymal cells, with different energy doses and different wavelengths, in addition to viability and wound closure. Mesenchymal stem cells derived from human adipocytes were irradiated with laser (energy of 0.5 J, 2 J and 4 J, wavelength of 660 nm and 830 nm), and LED (energy of 0.5 J, 2 J and 4 J, where lengths are 630 nm and 850 nm). The wound closure process was evaluated through monitoring the reduction of the lesion area in vitro. Viability was determined by analysis with Hoechst and Propidium Iodide markers, and quantification of viable and non-viable cells respectively Data distributions were analyzed using the Shapiro-Wilk test. Homogeneity was analyzed using Levene\'s test. The comparison between the parameters used was analyzed using the Two-way ANOVA test. The T test was applied to data relating to viability and lesion area. For LED photobiomodulation, only the 630 nm wavelength obtained a significant result in 24, 48 and 72 h (p = 0,027; p = 0,024; p = 0,009). The results related to the in vitro wound closure test indicate that both photobiomodulation with laser and LED demonstrated significant results considering the time it takes to approach the edges (p < 0.05). Considering the in vitro experimental conditions of the study, it is possible to conclude that the physical parameters of photobiomodulation, such as energy and wavelength, with laser or LED in mesenchymal stem cells, can play a potential role in cell viability and wound closure.
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