圆电流中导体的磁悬浮效应研究

本文基于椭圆积分法计算了圆电流产生的磁场,进而得到了导体在圆电流产生的高频电磁场中受力的解析表达式.结果表明:高频电磁场作用下,趋肤深度内的导体受到强烈的磁悬浮作用.频率越低,磁悬浮力的穿入深度越大,但其数值降低得越快.     

A lithium salt additive Li<Subscript>2</Subscript>ZrF<Subscript>6</Subscript> for enhancing the electrochemical performance of high-voltage LiNi<Subscript>0.5</Subscript>Mn<Subscript>1.5</Subscript>O<Subscript>4</Subscript> cathode

In this work, Li₂ZrF₆, a lithium salt additive, is reported to improve the interface stability of LiNi_0.5Mn_1.5O₄ (LNMO)/electrolyte interface under high voltage (4.9 V vs Li/Li⁺). Li₂ZrF₆ is an effective additive to serve as an in situ surface coating material for high-voltage LNMO half cells. A protective SEI layer is formed on the electrode surface due to the involvement of Li₂ZrF₆ during the formation of SEI layer. Charge/discharge tests show that 0.15 mol L^?1 Li₂ZrF₆ is the optimal concentration for the LiNi_0.5Mn_1.5O₄ electrode and it can improve the cycling performance and rate property of LNMO/Li half cells. The results obtained by electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) demonstrate that Li₂ZrF₆ can facilitate the formation of a thin, uniform, and stable solid electrolyte interface (SEI) layer. This layer inhibits the oxidation decomposition of the electrolyte and suppresses the dissolution of the cathode materials, resulting in improved electrochemical performances.     

应变率对Gr/Al金属基复合材料力学性能的影响

利用自行研制的冲击拉伸实验装置对单向石墨纤维增强铝基复合材料实施了不同应变率下的拉伸实验。获得了材料在００００５～１３００ｓ－１应变率范围内完整的应力应变曲线。结果表明Ｇｒ／Ａｌ的应力应变曲线可分为两个部分:非线性弹脆性变形以及材料失稳后的残余变形。实验结果还表明Ｇｒ／Ａｌ是一种应变率敏感材料,随着应变率的提高,材料的拉伸强度、失稳应变以及剩余应力均相应提高。根据不同应变率下的实验结果,提出了计及应变率强化效应的复合丝束统计本构模型,模型拟合的结果与实验结果吻合得很好。拟合结果还表明,特征纤维统计分布的Ｗｅｉｂｕｌ参数（尺度参数与形状参数）均是与应变率无关的,复合材料的应变率效应主要是由基体的应变率强化效应引起的。     

The double mode model of the chaotic motion for a large deflection plate

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因子分析-氢化物发生原子吸收法分析砷的形态

报道了用流动注射氢化物发生原子吸收法（ＦＩ－ＨＧＡＡＳ）对砷４种形态,Ａｓ,ＤＭＡ,ＭＭＡ）的混合体系进行测量后,根据吸光度加和性原则,用因子分析法（ＴＦＡ）对测定值进行解析,从而测定了混合体系中砷存在形态的数目、种类和含量。实验结果表明,不同酸度介质中不同形态砷校正曲线的斜率可作为相应的目标检测向量,应用于μｇ／Ｌ级低浓度砷的形态分析,平均回收率为９３．９％,结果令人满意。     

微流控芯片系统在单细胞研究中的应用

微流控芯片具有网络式通道结构,扩展了在细胞和亚细胞水平进行生命科学研究的能力,为单细胞研究提供了一个新的平台.在微流控芯片通道中,人们利用气压、液压和电压,或利用介电电泳、光学陷阱、行波介电电泳以及磁场等技术,可以操纵细胞通过或驻留在通道内的任意位置,从而使单细胞计数、筛选以及胞内组分分析等操作大大简化.本文对微流控芯片系统在血液流变学、单细胞操纵与计数以及单细胞胞内组分分析中的应用进行了综述,介绍了用于单细胞研究的多种微芯片系统,讨论了芯片上进行单细胞操纵的各种方法     

一类KKT系统的结构敏度分析

本文讨论一类KKT系统的敏度分析，这类KKT系统产生于用有限元方法离散Stokes方程，有结构特性．首先给出了最佳向后扰动界，接下来定义了偏条件数并导出了表达式．最后给出了新的扰动界．     

粉末压片-X-射线荧光光谱法分析砂岩型铀矿制样中粘结剂用量的探讨

由于砂岩型铀矿的成矿特性,样品粉末的内聚力小,采用直接压片法有时难以成型,样片表面常见裂纹,上机测量易碎裂。混合压片法适应性强,制样成功率高,但常见的问题是样品经粘结剂稀释会影响元素的检出限及结果的准确性。本文对粉末压片-X射线荧光光谱法测定砂岩型铀矿地质样品时,前期制样中添加粘结剂的比例进行了研究。试验按照不同比例在铀矿石标准物质GBW04101、GBW04102中添加粘结剂,在扫描电镜下观察到随着粘结剂用量的增加样片表面的光滑度及致密度都呈上升趋势,在X-射线荧光光谱仪上对主量元素进行测定后发现X射线强度在粘结剂添加量大于0.2 g时明显下降,经与GBW04101、GBW04102标准值进行对比后优选出粘结剂与样品的最佳比例为1：20,在此比例下制成的样片光滑平整,不易碎裂,用粉末压片-X射线荧光光谱法进行测定,标准物质测定结果的相对误差为0.56%～6.76 %,相对标准偏差(RSD,n=12)为0.013 %～7.68 %,均达到了《地质矿产实验室测试质量管理规范》DZ/T 0130-2006的要求。本文为粉末压片-X射线荧光光谱法分析砂岩型铀矿地质样品提供了可靠的实验参考依据。     

No Evidence of Induced Skin Cancer or Other Skin Abnormalities after Long-Term (66 week) Chronic Exposure to 222-nm Far-UVC Radiation

Far-UVC radiation, typically defined as 200–235 nm, has similar or greater anti-microbial efficacy compared with conventional 254-nm germicidal radiation. In addition, biophysical considerations of the interaction of far-UVC with tissue, as well as multiple short-term safety studies in animal models and humans, suggest that far-UVC exposure may be safe for skin and eye tissue. Nevertheless, the potential for skin cancer after chronic long-term exposure to far-UVC has not been studied. Here, we assessed far-UVC induced carcinogenic skin changes and other pathological dermal abnormalities in 96 SKH-1 hairless mice of both sexes that were exposed to average daily dorsal skin doses of 400, 130 or 55 mJ cm⁻² of 222 nm far-UVC radiation for 66 weeks, 5 days per week, 8 h per day, as well as similarly-treated unexposed controls. No evidence for increased skin cancer, abnormal skin growths or incidental skin pathology findings was observed in the far-UVC-exposed mice. In addition, there were no significant changes in morbidity or mortality. The findings from this study support the long-term safety of long-term chronic exposure to far-UVC radiation, and therefore its potential suitability as a practical anti-microbial approach to reduce airborne viral and bacterial loads in occupied indoor settings.     

Interphasial Pre-lithiation and Reinforcement of Micro-Si Anode through Fluorine-free Electrolytes

Micro-sized silicon (mSi) anodes offer advantages in cost and tap density over nanosized counterparts. However, its practical application still suffers from poor cyclability and low initial and later-cycle coulombic efficiency (CE), caused by the unstable solid electrolyte interphase (SEI) and irreversible lithiation of the surface oxide layer. Herein, a bifunctional fluorine (F)-free electrolyte was designed for the mSi anode to stabilize the interphase and improve the CE. A combined analysis revealed that this electrolyte can chemically pre-lithiate the native oxide layer by the reductive LiBH₄, and relieve SEI formation and accumulation to preserve the internal conductive network. The significance of this F-free electrolyte brings unprecedented F-free interphase that also enables the high-performance mSi electrode (80 wt % mSi), including high specific capacity of 2900 mAh/g, high initial CE of 94.7 % and excellent cyclability capacity retention of 94.3 % after 100 cycles at 0.2 C. This work confirms the feasibility of F-free interphase, thus opening up a new avenue toward cost-advantaged and environmentally friendly electrolytes for more emerging battery systems.