Influence of the crosstalk on the intensity of HAADF-STEM images of quaternary semiconductor materials

The influence of the neighbouring atomic-columns in determining the composition at atomic column scale of quaternary semiconductor compounds, using simulated HAADF-STEM images is evaluated. The InAlAsSb alloy, a promising material in the photovoltaic field, is considered. We find that the so called ‘crosstalk’ effect plays an important role for the aimed compositional determination. The intensity transfer is larger from neighbouring atomic columns with higher average Z, and towards atomic columns with smaller Z. Our results show that in order to obtain precise information on the column composition, the HAADF-STEM intensities of both columns need to be taken into account simultaneously.     

A generation method of artificial fluctuation data of wind power output considering smoothing effect

To use realistic wind power fluctuation data is important in simulating frequency change of power systems. It is well known that the smoothing effect must be taken into account when generating the artificial wind power output. Therefore, this paper proposed a new method to generate fluctuation waveform considering smoothing effect based on random number to fulfill the correlation among multiple sites and autoregression model. The effectiveness of the proposed method was tested by using practical wind speed data measured in Tohoku district.     

A new modification effect of eutectic Si in selective laser melted AlSi10Mg

A distinct modification of eutectic Si was observed in the selective laser melted AlSi10Mg. The eutectic Si particles were modified substantially and demonstrated a nanoscale size, a fibrous morphology with obvious ‘necking effect’. The modification mechanism and the influence of heat treatment on eutectic Si growth were explored. It was suspected that Si experienced the necking effect under a tensile environment due to the large temperature gradient and α-Al erosion during the SLM process. Upon heat treatment, the Si particles were spheroidised and distributed homogeneously. Under the synergistic action of Si crystal fragmentation and the continuous precipitation of saturated Si from the Al matrix, the coarsened and spheroidised eutectic Si were distributed homogeneously in the Al matrix.     

初诊无远处转移的穿刺病理Gleason评分10分前列腺癌的临床特点

目的　分析初诊无远处转移的穿刺病理Gleason评分为10分前列腺癌的临床特点并探讨外放疗联合内分泌治疗的疗效。方法　2003年1月至2014年3月北京协和医院收治初诊无远处转移的Gleason评分10分前列腺癌患者9例。所有患者均接受全盆腔外放疗联合长期内分泌治疗。全盆腔外放疗的照射剂量为50.0 Gy，前列腺、双侧精囊腺及区域阳性淋巴结加量至76.2～78.0 Gy。内分泌治疗采用最大限度雄激素阻断：口服抗雄激素药物加每月注射一次黄体生成素释放激素类似物。分析患者临床特点及联合治疗效果，并运用Kaplan-Meier法绘制生存曲线。 结果　患者中位随访时间为4.8年（26~75个月）。治疗前中位血清前列腺特异性抗原（prostate specific antigen，PSA）为11.2 μg/L，其中6例低于20 μg/L，3例高于70 μg/L。中位穿刺活检针数阳性率为90.9%。TNM分期：3例T2c，4例T3a，2例T3b；6例N0，3例N1；9例M0。随访期间，6例患者出现生化复发，其中5例进一步发展为转移性前列腺癌；4例患者死亡，其中3例死于前列腺癌。5年无生化复发率、无远处转移率、肿瘤特异性生存率及总体生存率分别为28.6%、 57.1%、66.7% 和57.1%。5例出现1～2级早期放疗胃肠道不良反应，6例出现1～2级早期泌尿系统不良反应，无晚期胃肠道及泌尿系统不良反应。无骨折、心血管意外等严重内分泌治疗并发症。 结论　初诊无远处转移的穿刺病理Gleason评分10分前列腺癌常伴穿刺阳性范围大、肿瘤分期偏晚等高危因素，患者通常预后不良，放疗联合内分泌治疗等及时和积极的综合治疗方案往往是必需的。     

Review of size effects in micro electrical discharge machining

Electrical discharge machining (EDM) is one of the most promising non-traditional micro-scale machining methods. Because several operating parameters that are insignificant in macro EDM cannot be neglected during micro EDM process, models derived from the macro EDM process may be inappropriate at the micro scale. This paper contains a comprehensive review of size effects in traditional micro-machining and characteristics specific to micro EDM compared to macro EDM techniques. The very concept of size effects in micro EDM is thoroughly defined and three categories of effects are presented: material microstructure, processing parameter and thermal conduction size effects. Future potential research directions on the subject are also summarized. We assert that careful research and precise attention must be given to size effects in micro EDM. Size effect information especially benefits the machining speed and machining precision of micro EDM.     

Optimization of graphene-MoS2 barristor by 3-aminopropyltriethoxysilane (APTES)

We theoretically and experimentally investigated the influence of the Fermi level position of graphene relative to the Dirac point on the performance of a graphene/MoS₂ heterojunction barristor. A large Fermi level modulation (ΔE_F = 0.28 eV) of graphene, when the V_GS is changed between −20 V and +20 V, was theoretically predicted when the Fermi level is located at the Dirac point. For reference, ΔE_F = 0.11 eV when the Fermi level is far from the Dirac point. This prediction was experimentally proven using two kinds of barristors with pristine (strongly p-type) and 2.4% APTES-treated (intrinsic) graphene. The on/off-current ratio was improved by a factor of 32 (a 2.1-fold increase in the on-current density and a 15-fold increase in the off-current density) in the APTES-treated device, as compared to the control. Using a temperature-dependent current-voltage measurement, we quantitatively confirmed the larger modulation of the barrier height in the APTES-treated barristor (ΔE_F = 0.27 eV) compared to that of the control device (ΔE_F = 0.14 eV). This study can be used to guide the design and optimization of graphene-based heterojunction devices.     

Frequency effect and influence of testing technique on the fatigue behaviour of quenched and tempered steel and aluminium alloy

Influences of testing technique and frequency on the fatigue behaviour of 50CrMo4 and EN AW-5083 were investigated. To clarify the effect of test frequency on the fatigue behaviour, tests with 20 kHz and f < 400 Hz were performed. The frequency effect can be caused by temperature, environment and strain rate. For the aluminium alloy, the influence of environment is responsible for the dependence of fatigue lifetime on the frequency. The fatigue lifetime of the steel showed in both environments similar frequency dependency, i.e. the strain rate is assumed to be responsible for the differences in fatigue lifetime.     

Highly selective sorting of semiconducting single wall carbon nanotubes exhibiting light emission at telecom wavelengths

Single wall carbon nanotubes (SWNTs) are known for their exceptional electronic properties.However,most of the synthesis methods lead to the production of a mixture of carbon nanotubes having different chiralities associated with metallic (m-SWNTs) and semiconducting (s-SWNTs) characteristics.For application purposes,effective methods for separating these species are highly desired.Here,we report a protocol for achieving a highly selective separation of s-SWNTs that exhibit a fundamental optical transition centered at 1,550 nm.We employ a polymer assisted sorting approach,and the influence of preparation methods on the optical and transport performances of the separated nanotubes is analyzed.As even traces of m-SWNTs can critically affect performances,we aim to produce samples that do not contain any detectable fraction of residual m-SWNTs.     

An efficient and secure cipher scheme for images confidentiality preservation

In this paper, a novel image encryption scheme based on two rounds of substitution–diffusion is proposed. Two main objectives have guided the design of this scheme: (a) robustness against the most known type of attacks (statistical, chosen/known plaintext, ciphertext-only and brute force attacks) and (b) efficiency in terms of computational complexity (i.e., execution time reduction) in order to meet recent mobiles’ applications’ requirements. First, a dynamic key, changed for every input image is generated and used as the basis to construct the substitution and diffusion processes. Then, the encryption process is performed by the transmitter based on a non-linear S-box (substitution) and a matrix multiplication (diffusion), applied on each sub-matrix of the image. At the destination side, decryption is applied in the reverse order. We have conducted several series of experiments to evaluate the effectiveness of the proposed scheme. The obtained results validated the robustness of our scheme against all considered types of attacks and showed an improvement in terms of execution time reduction compared to the recent existed image-encryption schemes.