Electrical properties of ITO/benzylated cyclodextrins (β-CDs (Bz))/Al diode structures

Abstract

Investigations of the electrical characteristics of benzylated cyclodextrins (β-CDs (Bz)) diodes are reported. We present current–voltage characteristics and impedance spectroscopy measurements performed on partially benzylated cyclodextrins β-CDs (Bz) thin films in sandwich structures ITO/b-CDs (Bz)/Al. The static electrical characterizations show a space charge limited conduction (SCLC) and a conductivity with power low frequency behavior characteristic of a hopping transport in disordered materials. The impedance spectra can be discussed in terms of an equivalent circuit model designed as a parallel resistor R_p and capacitor C_p network in series with resistor R_s. We extract numerical values of these parameters by fitting experimental data. Their evolution with bias voltages has shown that the SCLC mechanism is characterized by an exponential trap distribution. We estimated from the capacitance voltage characteristic an acceptor concentration of about 10¹¹ cm^?3 due to trap states.     

What Are the Biomarkers for Immunotherapy in SCLC?

Small-cell lung cancer (SCLC) is an aggressive malignancy that exhibits a rapid doubling time, a high growth fraction, and the early development of widespread metastases. The addition of immune checkpoint inhibitors to first-line chemotherapy represents the first significant improvement of systemic therapy in several decades. However, in contrast to its effects on non-SCLC, the advantageous effects of immunotherapy addition are modest in SCLC. In particular, only a small number of SCLC patients benefit from immune checkpoint inhibitors. Additionally, biomarkers selection is lacking for SCLC, with clinical trials largely focusing on unselected populations. Here, we review the data concerning the major biomarkers for immunotherapy, namely, programmed death ligand 1 expression and tumour mutational burden. Furthermore, we explore other potential biomarkers, including the role of the immune microenvironment in SCLC, the role of genetic alterations, and the potential links between neurological paraneoplastic syndromes, serum anti-neuronal nuclear antibodies, and outcomes in SCLC patients treated with immunotherapy.     

自密实轻骨料混凝土配合比设计及基本力学性能试验

采用全计算法中水量计算公式和固定砂石体积法中粗骨料、砂子的固定体积分数相结合的方法,根据流动扩展度和L槽试验参数优选出强度等级为SCLC40和SCLC50的自密实轻骨料混凝土的配合比。分析了自密实轻骨料混凝土的抗压强度、劈裂抗拉强度、抗折强度、弹性模量等主要力学性能参数,并与普通混凝土的基本力学性能进行了对比。结果表明:自密实轻骨料混凝土具有强度高、韧性好、弹性模量小等特点,所得结论为自密实轻骨料混凝土的工程应用提供了参考。     

自密实轻骨料混凝土配合比设计及基本力学性能试验

采用全计算法中水量计算公式和固定砂石体积法中粗骨料、砂子的固定体积分数相结合的方法,根据流动扩展度和I。槽试验参数优选出强度等级为SCLC40和SCLC50的自密实轻骨料混凝土的配合比。分析了自密实轻骨料混凝土的抗压强度、劈裂抗拉强度、抗折强度、弹性模量等主要力学性能参数,并与普通混凝土的基本力学性能进行了对比。结果表明：自密实轻骨料混凝土具有强度高、韧性好、弹性模量小等特点,所得结论为自密实轻骨料混凝土的工程应用提供了参考。     

氧化镍溶胶-凝胶薄膜阻变特性研究

用溶胶-凝胶法在1TO基片上旋涂制备了NiO薄膜,通过对ITO/NiO薄膜/GaIn器件进行伏安特性测试,研究了溶胶浓度、退火、层数以及Cu掺杂等对其电学特性的影响.结果表明:所制备NiO薄膜具有良好可重复双极电阻开关特性.其中,2％Cu掺杂0.2 mol/L溶胶、双层、400℃退火1h制备的薄膜,阈值电压较低,约0.8 V;而开关比受以上因素影响不明显,约3× 102.分析发现薄膜高阻态的荷电输运符合空间电荷限制导电机制,而低阻态为欧姆特性,阻变开关机理为阈值电场及焦耳热导致的氧空位细丝的形成与断裂.     

Evaluation of the gap state distribution in a-Si:H by SCLC measurements

In this work, the analysis of the current density–voltage (J–V) characteristics of a good-quality a-Si:H n⁺–i–n⁺ structures has been studied as a function of temperature. The defect density within the intrinsic layer of the a-Si:H n⁺–i–n⁺ structure was determined using the den Boer approach to the analysis of the space charge limited current (SCLC). The den Boer analysis yields the density of states (DOS) in only a limited part of the band gap of the sample. We emphasize that in a good-quality sample, even if it is a thin one, the den Boer approach to SCLC gives correct information about the DOS. This information comes from the states near the conduction band tail, which reside in the upper part of the gap, because of the smaller activation energy of thin samples.     

Effect of some metallic impurities on the density of localized states in a-Se80Te20 thin films

The present paper reports the d.c. conductivity measurements at high electric fields in vacuum-evaporated thin films of amorphous Se₈₀Te₂₀, Se₇₅Te₂₀Ge₅ and Se₇₅Te₂₀Sb₅ systems. Current-voltage (I-V) characteristics have been measured at various fixed temperatures. In all the samples, at low electric fields ohmic behavior is observed. However, at high electric fields (E∼10⁴ V/cm), non-ohmic behavior is observed. An analysis of the experimental data confirms the presence of space charge limited conduction (SCLC) in all the glassy materials studied in the present case. From the fitting of the data to the theory of SCLC, the density of defect states (DOS) near Fermi level is calculated. The role of the aforesaid impurities in a-Se₈₀Te₂₀ is found to be entirely different. In case of Sb, an increase in DOS is observed. However, a decrease is observed in case of Ge. The change in DOS on impurity incorporation is explained in terms of the change in structure of these glasses.     

Dependence of charge carrier mobility of 4,4′,4″-tris(N-3-methylphenyl-N-phenylamino)triphenylamine on doping concentration of tetrafluoro-tetracyano-quinodimethane

Electrical transport of pure and tetrafluoro-tetracyano-quinodimethane doped 4,4′,4″-tris(N-3-methylphenyl-N-phenylamino)triphenylamine (m-MTDATA) films have been studied at various temperatures and doping concentrations. Pure films show space charge limited conduction with field and temperature dependent mobility. The J-V characteristics of doped m-MTDATA were ohmic at low voltages due to thermally released carriers from dopant states. At higher voltages the current density increases nonlinearly due to field dependent mobility and carrier concentration thereby filling of tail states of HOMO of the host. The conductivity of doped films were analysed using the Unified Gaussian Disorder Model (UGDM). The carrier concentration obtained from the fitting show a non-linear dependence on doping concentration which may be due to a combined effect of thermally activated carrier generation and increased carrier mobility.     

PLT铁电薄膜的漏电流与I—V特性的研究

室温下在ＭＯＤ法制备的ＰＬＴ铁电薄膜的样品上，观察不同电场强度下电流随时间的变化，根据电流的变化情况，把电场划分为弱、中、强三个区间。在弱场下，电流随时间的变化可用幂指数的衰减来模拟，而且衰减系数随场强的增加有减小的趋势。在中强场时，电流随时间在水平方向上上下波动。在强场下，电流随时间在波动的同时不断增大。因此在对不同区间电流随时间变化Ｉ（ｔ）曲线分析的基础上，确定某一电场强度下的漏导电流，作出了Ｉ－Ｖ曲线。同时发现不同配方，在相同工艺条件下的样品，其弱、中、强场的数值区间是不一样的，因此作出的Ｉ－Ｖ曲线也有所区别。对非欧姆区的导电机理用空间电荷限制电流（ＳＣＬＣ）模型和晶界限制电流（ＧＢＬＣ）模型来解释，同时对样品正向与反向的导电机理进行了对比研究。而且对热释电电流测量中有指导意义的薄膜充电后缓慢的放电过程进行了观察和分析     

钢聚丙烯混杂纤维自密实轻骨料混凝土性能

采用钢纤维和聚丙烯纤维对自密实轻骨料混凝土进行改性,完成了 1组无纤维自密实轻骨料混凝土及4组钢-聚丙烯混杂纤维自密实轻骨料混凝土的工作性能、力学性能及微观结构的试验研究,从宏观与微观2个尺度系统分析了钢-聚丙烯混杂纤维的增强增韧机理.结果表明:5组自密实轻骨料混凝土均具有良好的流动性、黏聚性和间隙通过性,可满足自密实混凝土工作性要求;钢纤维与聚丙烯纤维可在不同结构层次和受荷阶段发挥阻裂作用,产生正协同效应,显著提高自密实轻骨料混凝土的劈裂抗拉强度和抗折强度;骨料-基体界面区的密实度随养护龄期延长而明显提高,而纤维与基体间存在微细孔隙,界面区结构较为松散.