Influence Predictions of Contact Effects on Mesh Stiffness of Face Gear Drives with Spur Gear

Mesh stiffness is one of important base parameters of face gear dynamic studies.However,a calculation solution of mesh stiffness of face gear drives is not to be constructed due to complex geometric flakes of face gear teeth.Thus,a calculation solution of mesh stiffness of face gear drives with a spur gear,which is based on the proposed equivalent face gear teeth and Ishikawa model,is constructed,and the influence of contact effects on mesh stiffness of face gear drives is investigated.The results indicate the mesh stiffness of face gear drives is sensitive to contact effects under heavy loaded operating conditions,specially.These contributions will benefit to improve dynamic studies of face gear drives.

Analytical modeling and approaches of multihelix cables incorporating with interwire mutual contacts

This study aims to develop an analytical model based on the curve beam theory to capture the mechanical response of a multihelix cable considering the internal contact displacements.Accordingly,a double-helix cable subjected to axial tension and torsion is analyzed,and both the line and point contacts between the neighboring wires and strands are considered via an equivalent homogenized approach.Then,the proposed theoretical model is extended to a hierarchical multihelix cable with mutual contact displacements by constructing a recursive relationship between the high-and low-level multihelix structures.The global tensile stiffness and torsional stiffness of the double-helix cable are successfully evaluated.The results are validated by a finite element(FE)model,and are found to be consistent with the findings of previous studies.It is shown that the contact deformations in multihelix cables significantly affect their equivalent mechanical stiffness,and the contact displacements are remarkably enhanced as the helix angles increase.This study provides insights into the interwire/interstrand mutual contact effects on global and local responses.

Distinction between critical current effects and intrinsic anomalies in the point-contact Andreev reflection spectra of unconventional superconductors

In this work,we discuss the origin of several anomalies present in the point-contact Andreev reflection spectra of（Li1-xFex）OHFeSe,LiTi2O4,and La2-xCexCuO4.While these features are similar to those stemming from intrinsic superconducting properties,such as Andreev reflection,electron-boson coupling,multigap superconductivity,d-wave and p-wave pairing symmetry,they cannot be accounted for by the modified Blonder–Tinkham–Klapwijk（BTK） model,but require to consider critical current effects arising from the junction geometry.Our results point to the importance of tracking the evolution of the dips and peaks in the differential conductance as a function of the bias voltage,in order to correctly deduce the properties of the superconducting state.

Hunting down the ohmic contact of organic field-effect transistor

We report properties of contact resistances observed on pentacene organic field-effect transistors(OFET) with four different source/drain electrodes, namely, copper(Cu), gold(Au), silver(Ag), and germanium(Ge). The metals were selected to provide a wide range of energy barriers for charge injection, from blocking contact to smooth injection. All OFETs exhibited strong voltage dependence of the contact resistance, even for devices with smooth injection, which is in strong disagreement with the definition of ohmic contacts. A comparison with current crowding, resistive network, Fowler–Nordheim tunneling, and electric field enhanced thermionic injection(Schottky emission) pointed to importance of local electric fields and/or electrostatic field charges.

Reiterated homogenization of a laminate with imperfect contact:gain-enhancement of effective properties

A family of one-dimensional(1D) elliptic boundary-value problems with periodic and rapidly-oscillating piecewise-smooth coefficients is considered. The coefficients depend on the local or fast variables corresponding to two different structural scales. A finite number of imperfect contact conditions are analyzed at each of the scales. The reiterated homogenization method(RHM) is used to construct a formal asymptotic solution. The homogenized problem, the local problems, and the corresponding effective coefficients are obtained. A variational formulation is derived to obtain an estimate to prove the proximity between the solutions of the original problem and the homogenized problem. Numerical computations are used to illustrate both the convergence of the solutions and the gain of the effective properties of a three-scale heterogeneous 1D laminate with respect to their two-scale counterparts. The theoretical and practical ideas exposed here could be used to mathematically model multidimensional problems involving multiscale composite materials with imperfect contact at the interfaces.

Effect of Metal Contact and Rapid Thermal Annealing on Electrical Characteristics of Graphene Matrix

Development of graphene field effect transistors （GFETs） faces a serious challenge of graphene interface to the dielectric material. A single layer of intrinsic graphene has an average sheet resistance of the order of 1-5 kΩ/□. The intrinsic nature of graphene leads to higher contact resistance yielding into the outstanding properties of the material. We design a graphene matrix with minimized sheet resistance of 0.185 kΩ/□ with Ag contacts. The developed matrices on silicon substrates provide a variety of transistor design options for subsequent fabrication. The graphene layer is developed over 400 nm nickel in such a way as to analyze hypersensitive electrical properties of the interface for exfoliation. This work identifies potential of the design in the applicability of few-layer GFETs with less process steps with the help of analyzing the effect of metal contact and post-process anneMing on its electrical fabrication.

Top contact organic field effect transistors fabricated using a photolithographic process

This paper proposes an effective method of fabricating top contact organic field effect transistors by using a pho- tolithographic process. The semiconductor layer is protected by a passivation layer. Through photolithographic and etching processes, parts of the passivation layer are etched off to form source/drain electrode patterns. Combined with conventional evaporation and lift-off techniques, organic field effect transistors with a top contact are fabricated suc- cessfully, whose properties are comparable to those prepared with the shadow mask method and one order of magnitude higher than the bottom contact devices fabricated by using a photolithographic process.

Experimental I-V and C-V Analysis of Schottky-Barrier Metal-Oxide-Semiconductor Field Effect Transistors with Epitaxial NiSi2 Contacts and Dopant Segregation

We present an experimental analysis of Schottky-barrier metal-oxide-semiconductor field effect transistors （SB- MOSFETs） fabricated on ultrathin body silicon-on-insulator substrates with a steep junction by the dopant implantation into the silicide process. The subthreshold swing of such SB-MOSFETs reaches 69mV/dec. Em- phasis is placed on the capacitance-voltage analysis of p-type SB-MOSFETs. According to the measurements of gate-to-source capacitance Cgs with respect to Vgs at various Vds, we find that a maximum occurs at the accumulation regime due to the most imbalanced charge distribution along the channel. At each Cgs peak, the difference between Vgs and Vds is equal to the Schottky barrier height （SBH） for NiSi2 on highly doped silicon, which indicates that the critical condition of channel pinching off is related with SBH for source/drain on chan- nel. The SBH for NiSi2 on highly doped silicon can affect the pinch-off voltage and the saturation current of SB-MOSFETs.

Study of top and bottom contact resistance in one organic field-effect transistor

This paper reports that the organic field-effect transistors with hybrid contact geometry were fabricated, in which the top electrodes and the bottom electrodes were combined in parallel resistances within one transistor. With the facility of the novel structure, the difference of contact resistance between the top contact geometry and the bottom contact geometry was studied. The hybrid contact devices showed similar characteristics with the top contact configuration devices, which provide helpful evidence on the lower contact resistance of the top contact configuration device. The origin of the different contact resistance between the top contact device and the bottom contact device was discussed.

Preprocessing and Efficacy Analysis of Comprehensive Anti-Inflammatory Treatment for Lymphedema in Patients with Irritating Contact Dermatitis

Objective: To explore the pre-treatment and efficacy analysis of comprehensive anti-inflammatory treatment for lymphedema in patients with irritating contact dermatitis. Method: Convenience sampling method was used to observe the skin of 160 patients with upper limb lymphedema admitted to the lymphedema outpatient department of our hospital. They were divided into an observation group (80 cases) and a control group (80 cases), and both groups received a course of comprehensive anti-inflammatory treatment (20 treatments). The control group received routine skin care;On the basis of the control group, the observation group received pre-treatment of the affected limb skin: Laofuzi herbal ointment was applied externally to the prone areas of irritating contact dermatitis (such as the upper arm, inner forearm, and cubital fossa). Result: The incidence of irritating contact dermatitis in the observation group was significantly lower than that in the control group (P 0.05). Patients in the observation group felt significantly better in terms of comfort, skin moisture, and itching relief after being wrapped with low elasticity bandages than those in the control group (P Conclusion: Preventive treatment can effectively reduce the incidence of irritating contact dermatitis, prolong the time of stress treatment, thereby increasing efficacy and improving patient compliance.

Potential Power of the Pyramidal Structure III: Discovery of Pyramid Effects with and without Seasonal Variation

Since October 2007, we have been conducting rigorous scientific research on the unexplained “power” of a pyramidal structure (PS). From our research results so far, we could classify the pyramid effects by the PS into the following two types. (i) The pyramid effects in which the PS converted the test subject’s unexplained energy to affect biosensors when the test subject entered the PS and meditated. (ii) The pyramid effects in which the potential power of the PS affected biosensors if the test subject had not been inside the PS for at least 20 days and the test subject’s unexplained energy was excluded. In this paper, we report new results regarding (ii). As a result of dividing a year according to the four seasons of winter, spring, summer, and autumn and analyzing the pyramid effect of each period, the following points were found. 1) There was a pyramid effect without seasonal variation. The pyramid effect on the lower and upper layers was different throughout the year for the biosensors placed at the PS apex in two layers, regardless of the season. 2) There was a pyramid effect with seasonal variation. The value of the psi index, which indicates the magnitude of the pyramid effect, changed as the seasons changed, while different pyramid effects were maintained on the lower and upper layers. Regarding the change in the pyramid effect depending on the season, the psi index in summer was larger than that in winter in both the lower and upper layers. From these results, we found that there are two types of potential power at the PS apex: seasonal potential power and non-seasonal potential power.

Potential Power of the Pyramidal Structure IV: Discovery of Entanglement Due to Pyramid Effects

Since October 2007, we have been conducting rigorous scientific research on the unexplained “power” of a pyramidal structure (PS). From our research results so far, we could classify pyramid effects by the PS into the following two types: (i) the pyramid effects due to the potential power of the PS and (ii) the pyramid effects due to the influence of the test subject meditating inside the PS. We have been using edible cucumber sections as the biosensors. The pyramid effect existence was clarified by measuring and analyzing the concentration of volatile components released from the biosensors. The biosensors were arranged as a pair: one member of the pair was placed at the PS apex and the other was placed at the calibration control point 8.0 m away from the PS. In this paper, we report a new discovery regarding the type (i) pyramid effects. We discovered a phenomenon considered to be entanglement between the biosensor pairs detecting the pyramid effects. In other words, the biosensors at the PS apex, which were affected by the potential power of the PS, affected the biosensors at the calibration control point. We also confirmed that the effects on the biosensors placed at the calibration control point were not due to the potential power of the PS. Furthermore, we showed that the magnitude of the effect of entanglement changed with the seasons. We expect that our research results will be widely accepted in the future and will become the foundation for a new research field in science, with a wide range of applications.

我国红火蚁防治药剂应用现状、防效评价及防控对策

红火蚁(Solenopsis invicta Buren)是重大外来入侵有害生物,自2004年在广东吴川发现以来,已扩散蔓延至我国多个省市,危害人体健康和生态环境。化学防治是目前红火蚁防治中应用最普遍、最有效的方法,本文系统总结了饵剂和触杀性药剂的有效成分及市场销售情况,对比探讨了饵剂诱杀、粉剂灭杀和药液灌巢等措施的防治效果,并针对不同生境红火蚁的发生特点提出了防控建议,为我国红火蚁科学防控和合理用药提供参考依据。

Depositing aluminum as sacrificial metal to reduce metal–graphene contact resistance

Reducing the contact resistance without degrading the mobility property is crucial to achieve high-performance graphene field effect transistors. Also, the idea of modifying the graphene surface by etching away the deposited metal provides a new angle to achieve this goal. We exploit this idea by providing a new process method which reduces the contact resistance from 597Ω ·μm to sub 200 Ω ·μm while no degradation of mobility is observed in the devices. This simple process method avoids the drawbacks of uncontrollability, ineffectiveness, and trade-off with mobility which often exist in the previously proposed methods.

Profiled Cylindrical Roller Design in Consideration of Grinding Undercut Effect

In this paper, the effect of the grinding undercut of the raceways on the longitudinal pressure distribution of the profiled rollers, which are the most popular axial profile employed by the bearing manufacturers, was discussed. Based on the profiled roller geometrical equations and numerical calculation of three dimensional elastic contact problems of finite length, a new numerical method for calculating the crown drop evaluation considering the effect of grinding undercut was used. The analyses of two structure case, that roller length is greater or less than raceway width, were carried out and compared with each other. The Results show that the width of grinding undercut must be considered in determining the crown drop of rollers.

Profile Characterization and Temperature Effect on the Wettability of Microstructured Surfaces

Wetting is one of the omnipresent phenomena governed via natural laws. Moreover, surface wettability at non-ambient temperature especially at high temperature (30°C to 90°C) is of great importance in many industrial processes. In this study, Si wafers with various structures were fabricated to investigate wettability at different temperatures. Three shapes with micro-pillar structured surfaces were designed and fabricated. Pillar-structured surfaces were fabricated by photolithography and ICP etching. The temperature-dependent wettability of single-phase regime droplets was characterized using contact angle measurements. The wetting behavior of a water droplet was observed.

Current transport mechanism of Mg/Au ohmic contacts to lightly doped n-type β-Ga_2O_3

The carrier transport mechanism of Mg/Au ohmic contact for lightly doped β-Ga_2O_3 is investigated. An excellent ohmic contact has been achieved when the sample was annealed at 400 °C and the specific contact resistance is 4.3 × 10-4 Ω·cm2. For the annealed sample, the temperature dependence of specific contact resistance is studied in the range from 300 to 375 K. The specific contact resistance is decreased from 4.3 × 10-4 to 1.59 × 10-4 Ω·cm2 with an increase of test temperature. As combination with the judge of E00, the basic mechanism of current transport is dominant by thermionic emission theory. The effective barrier height between Mg/Au and β-Ga_2O_3 is evaluated to be 0.1 eV for annealed sample by fitting experimental data with thermionic emission model.

Effect of the Morphology of Leather Surface on the Hydrophobic-Hydrophilic Properties

Natural leathers (split, velour split, nubuck) ware investigated. Solution of fluorine silane in ethanol was applied as the hydrophobic agent. It is shown that the microstructure of the leather surface, provided its structural elements possess hydrophilic properties, determines the wetting regime and duration of the induction period of changeover from heterogeneous to homogeneous wetting. The heterogeneous regime of wetting is distinguished by low rates of spreading and absorbing. The homogeneous wetting is characterized by high rates of spreading and absorbing of a water drop. A necessary condition of the stable heterogeneous wetting regime and achieving hydrophobicity of leather with structurally inhomogeneous face layer is to preserve the microstructure features of their surface at hydrophobic treatment. The morphological peculiarities of split and ground leather ensure stable hydrophobic properties after application of efficient hydrophobizators.

四种助剂对防治褐飞虱的植物源农药1%印楝素水分散粒剂毒力的影响

【目的】本研究旨在探究橙皮精油(orange peel essential oil,OPEO)、γ-氨基丁酸(γ-aminobutyric acid,GABA)、卵磷脂及马来酸二乙酯(diethyl maleate,DEM)4种助剂对植物源农药1%印楝素水分散粒剂(water dispersible granule,WG)毒力的影响,筛选出有增效作用的助剂,将其作为1%印楝素WG防治褐飞虱Nilaparvata lugens的桶混助剂。【方法】利用稻苗浸渍法和连续浸液法评价印楝素及添加助剂OPEO、GABA、卵磷脂或DEM后对褐飞虱3龄若虫的毒力;测定印楝素(20 mg a.i./L)及添加助剂处理后,褐飞虱3龄若虫体内谷胱甘肽S-转移酶(glutathione S-transferase,GST)、羧酸酯酶(carboxylesterase,CarE)及乙酰胆碱酯酶(acetylcholinesterase,AChE)3种酶活性;测定添加助剂后对印楝素药液(40 mg a.i./L)与水稻叶片接触角的影响。【结果】稻苗浸渍法处理后96 h,添加DEM使印楝素对褐飞虱3龄若虫胃毒性毒力显著增强,增效比为1.512;连续浸液法处理后72 h,添加OPEO或DEM使印楝素对褐飞虱3龄若虫内吸性毒力显著增强,其增效比分别为1.486及1.560;添加OPEO或DEM分别使褐飞虱3龄若虫体内GST活性比印楝素单剂处理分别降低69.4%和65.5%;添加DEM使CarE活性比印楝素单剂处理降低88.2%;添加OPEO或DEM后,印楝素药液液滴与水稻正面叶片的初始接触角从110°分别降至64.5°或67.9°。【结论】添加OPEO或DEM能明显提高印楝素对褐飞虱的毒力,提高印楝素药液在水稻叶片上的润湿性。因此,将OPEO或DEM作为1%印楝素WG防治褐飞虱的桶混助剂有一定的应用价值。

壳聚糖抗菌成膜喷剂在鼻咽癌患者PICC所致接触性皮炎治疗中的应用效果

目的探讨壳聚糖抗菌成膜喷剂在鼻咽癌患者经外周静脉置入中心静脉导管(PICC)置管部位接触性皮炎治疗中的应用效果。方法选取2020-05至2022-04联勤保障部队第909医院因置入PICC所致接触性皮炎的94例鼻咽癌患者为研究对象,其中2020-05至2021-04的46例患者为对照组,2021-05至2022-04的48例患者为观察组。对照组采用地塞米松注射液外涂联合3M透明敷料行PICC换药,观察组采用喷涂壳聚糖抗菌成膜喷剂联合3M透明敷料行PICC换药。对比观察两组患者临床疗效、并发症的发生率、愈合时间、换药次数、患者的自付费用及满意度情况。结果观察组治疗第1周、第2周总有效率(95.83%,100%)均显著高于对照组治疗总有效率(73.91%,89.13%)(P<0.05),观察组愈合时间[(10.43±0.52)d]、换药次数[(3.30±0.69)次]显著短于或少于对照组愈合时间[(18.15±0.33)d]、换药次数[(5.67±0.96)次](P<0.05),观察组患者满意度得分(8.71±0.82)显著高于对照组患者满意度得分(5.67±0.96)(P<0.05),两组患者在导管移位率、脱管率及患者自付费用三方面无明显区别,差异无统计学意义(P>0.05)。结论壳聚糖抗菌成膜喷剂治疗鼻咽癌同步放化疗患者PICC置管部位接触性皮炎效果明显,可减少换药次数,减轻护理工作量,降低局部感染率,提高患者满意度。