摘要：In this work,a set of novel Cu2ZnSnS4/Bi2WO6(CZTS/BWO)two-dimensional(2 D)/two-dimensional(2 D)type-Ⅱheterojunctions with different CZTS weight ratios(1%,2%,and 5%)were successfully synthesized via a brief secondary solvothermal *** successful formation of the heterojunctions was affirmed by characterization methods such as X-ray photoelectron spectroscopy and high-resolution transmission electron *** photocatalytic activity results showed that the prepared CZTS/BWO heterojunctions had excellent photocatalytic behaviors for organic degradation,especially when the mass fraction of CZTS with respect to BWO in the composite was 2%.Moreover,the addition of hydrogen peroxide(H2O2)could further improve the dye and antibiotic degradation *** reinforced photocatalytic and photo-Fenton degradation performance were primarily attributable to the introduction of BWO,which afforded increased active sites,expanded the solar spectral response range,and accelerated the cycle of Cu(Ⅱ)/Cu(Ⅰ);after four cycling times,its catalytic activity did not decrease *** addition,reasonable hypotheses of the photocatalytic and photo-Fenton catalytic mechanisms were *** study is expected to provide a visual approach for designing a novel photo-Fenton catalyst to jointly utilize the photocatalytic and Fenton activities,which can be better applied to the purification of residual organics in wastewater.

摘要：Laser additive manufacturing technology with powder feeding was employed to repair wrought Ti17titanium alloy with small surface *** microstructure,micro-hardness and room temperature tensile properties of laser additive repaired(LARed)specimen were *** results show that,cellular substructures are observed in the laser deposited zone(LDZ),rather than the typicalαlaths morphology due to lack of enough subsequent thermal *** cellular substructures lead to lower micro-hardness in the LDZ compared with the wrought substrate zone which consists of duplex *** tensile test results indicate that the tensile deformation process of the LARed specimen exhibits a characteristic of dramatic plastic strain heterogeneity and fracture in the laser repaired zone with a mixed dimple and cleavage *** tensile strength of the LARed specimen is slightly higher than that of the wrought specimen and the elongation of11.7%is lower.

摘要：【目的】研究不同修剪施肥处理对茶树产量与品质的影响,为春茶高质量生产提供技术参考。【方法】以茶树品种‘白叶1号’和‘槠叶齐’为试验材料,基于正交试验设计,研究修剪时间、修剪高度、施肥水平对次年春茶产量和生化品质的影响。【结果】提早修剪时间和增加修剪高度显著提高了茶树枝条数量和高度,对枝条茎粗无显著影响;不同修剪时间和修剪高度对春茶产量的影响存在显著差异(P<0.05),修剪时间为5月17日(A1)、修剪高度为55 cm(B3)时春茶产量较高;施肥水平为尿素225 kg·hm^(-2)+磷酸钾复合肥750 kg·hm^(-2)+有机肥3000 kg·hm^(-2)(C3)时,茶叶中茶多酚、儿茶素总量及氨基酸等物质积累较多,春茶鲜叶产量亦较高,故‘白叶1号’和‘槠叶齐’均以处理Ⅲ(A1B3C3)的春茶产量最高,分别为1170.24 kg·hm^(-2)和1261.85 kg·hm^(-2),较对照[10月15日修剪,修剪高度为离地70 cm,施肥水平为C2(尿素150 kg·hm^(-2)+磷酸钾复合肥600 kg·hm^(-2)+有机肥2250 kg·hm^(-2))]分别高36.77%和46.28%。【结论】修剪施肥影响次年春茶产量和生化品质,修剪时间为5月17日、修剪高度为55 cm、施肥水平为C3的处理Ⅲ为适宜的修剪施肥组合。

摘要：为了解高性能桥梁耐候钢典型焊缝接头的疲劳特性,设计、制作Q370qNH高性能桥梁耐候钢对接焊缝、T形焊缝和十字形焊缝接头试件进行疲劳试验。分析3类焊缝接头试件疲劳破坏模式、疲劳寿命与疲劳强度,并将试验拟合的S~N对数曲线与现行规范结果进行对比;基于收集的141个疲劳试验结果,分析高性能桥梁耐候钢典型焊缝接头和传统结构钢同类焊缝接头疲劳特性的差异。结果表明:3类耐候钢焊缝接头均发生了焊趾处的疲劳失效破坏,设计、施工时应重点关注;随着加载应力幅的增加,3类接头的疲劳寿命按幂指数形式逐渐降低;在与规范相同保证率条件下,计算的桥梁耐候钢对接焊缝疲劳强度分别是《钢结构设计标准》(GB 50017—2017)的1.30倍、《铁路桥梁钢结构设计规范》(TB 10091—2017)的1.14倍;T形焊缝接头表现出最好的抗疲劳性能,现行规范中对其疲劳强度的评估偏于保守;十字形焊缝接头95%保证率S~N对数曲线和《钢结构设计标准》设计曲线吻合较好。

摘要：At present,equivalent water depth truncated mooring system optimization design is regarded as the priority of hybrid model testing for deep sea platforms,and will replace the full depth system test in the *** with the full depth system,the working depth and span are smaller in the truncated one,and the other characteristics maintain more consistency as *** this paper,an inner turret moored floating production storage ＆ offloading system（FPSO） which works at a water depth of 320m,was selected to be a research example while the truncated water depth was ***,an improved non-dominated sorting genetic algorithm（INSGA-II） was selected to optimally calculate the equivalent water depth truncated system,considering the stress condition of the total mooring system in both the horizontal and vertical directions,as well as the static characteristic similarity of the representative single mooring *** results of numerical calculations indicate that the mathematical model is feasible,and the optimization method is fast and effective.

摘要：激光选区熔化成形技术作为一种近净成形的增材制造技术,可实现复杂结构零部件高精度成形。为此,结合激光选区熔化实际应用中发现的问题,总结了激光选区熔化成形工艺的零部件设计准则,包括变形、粉料去除、支撑去除、扫描策略、设备加工能力、加工余量等,同时,结合实际应用情况,进一步分析了应力收缩线形成机理及常规应力分布规律。该研究为设计人员进行零部件设计、模型优化提供了依据。

摘要：Cascading stages of high-gain harmonic generation(HGHG) free electron laser(FEL) is a promising way to produce fully coherent X-ray *** a test facility for modern FEL R&D,the Shanghai deep ultraviolet FEL(SDUV-FEL) is now under upgrading for the cascading two stages of HGHG *** the energy of the electron beam is as low as about 185 MeV after upgrade,the total harmonic number of this two stages HGHG is only 2×2,and the wavelength of the final radiation is 196.5 nm which is the 4th harmonic of the 786 nm seed *** help of three-dimensional simulation codes,design studies on the FEL physics for the cascaded HGHG experiment are present based on the parameters of the upgraded SDUV-FEL *** is found from the simulation results that the part of the electron beam which has been used in the first stage can still generate powerful radiation in the radiator of the second stage,and this radiation will be difficult to be separated from the radiation generated by the fresh part of the electron *** overcome this problem,a novel method based on the energy spectrum of the electron beam is proposed in this paper to demonstrate the "fresh bunch" technique.

摘要：自然界中飞行生物利用肌肉、骨骼等结构的协同作用实现灵活、敏捷的飞行,具有扑动、悬停、滑翔等多种飞行模式.仿生扑翼飞行器是模拟鸟类和昆虫等飞行模式的一类飞行器,通过机翼的周期性上下扑动产生飞行所需的升力和推力,具有隐蔽性好、能效高和飞行噪声小等优点,得到了各研究机构的广泛关注.由于扑翼飞行器自身的负载能力较小,很难携带大容量的电池,导致其续航时间有限.研究新型轻质高能量密度的电池和高仿生设计实现续航时间的提升,是扑翼飞行器重要的研究方向.但是,针对扑翼飞行器新型电池的研究还处于初级研发阶段,尚不具备机载飞行测试的能力.研究人员从仿生机理分析、机构优化设计以及控制策略研究等方面入手,针对扑翼飞行器能耗问题开展了大量研究,并取得了阶段性成果.总结了有关仿生扑翼飞行器能耗方面的研究进展,分析了静态参数、动态参数和控制策略等对仿生扑翼飞行器能耗的影响,提出了降低能耗的措施,并对未来研究方向做出了展望.

摘要：仿生扑翼飞行器的设计灵感来源于自然界中的鸟类、昆虫和蝙蝠的飞行模式,通过机翼的主动运动来产生飞行所需要的升力和推力.仿生扑翼飞行器具有隐蔽性好、机动性强等优点,成为近年来国内外飞行器研究的重点.但是仿生扑翼飞行器研究涉及到低雷诺数、非定常空气动力学等问题,与常规固定翼飞行器有很大的不同.仿生扑翼飞行器的研究方法一般分三种:气动计算、风洞实验和外场试飞.气动计算方面,非定常气动设计优化理论与方法目前仍存在不足;外场试飞的方法无法精确测量出飞行器复杂的气动力,难以对飞行器进行定量分析研究;风洞实验由于可以模拟飞行时的真实情况,获得的数据较为真实可靠,且可以定量分析研究,成为目前研究仿生扑翼飞行器非常有效的方法.国内外研究人员利用风洞进行了大量针对仿生扑翼飞行器的实验研究.在介绍了风洞组成和分类的基础上,详细阐述了仿鸟和仿昆虫扑翼飞行器风洞实验的研究现状,最后对仿生扑翼飞行器风洞实验未来可能的研究方向给出了建议.

摘要：设计开发了一种无凸轮电液可变气门机构(EHVVA),建立了该可变气门机构动态特性试验平台,通过试验探索了EHVVA在4种发动机转速(2500、2000、1500和1000 r/min)下的动态运行特性.与凸轮驱动气门机构不同,EHVVA运行特性受发动机转速影响较小,丰满系数高于传统凸轮驱动气门机构;高速工况下EHVVA加速度峰值低因而具有更小的往复惯性力.EHVVA的柱塞腔内油压在单循环内的变化可分为油压建立阶段、油压保持阶段和油压卸荷阶段.随着发动机转速的提高,需提高驱动油压以实现气门快速开启,同时随着信号脉宽变短,气门运动逐渐由充分响应转换为非充分响应状态.探索了EHVVA的循环变动特性,结果表明:柱塞腔最大油压、最大升程及时面值的循环变动率均小于4%.