番茄红素中砷含量测定

以氢化物生成法为砷原子化手段,采用原子吸收分光光度法测定番茄红素中砷含量.本实验选定条件下,砷的检测限为8×10-10,精密度RSD为3.2%,准确度以回收率计为94.5%.结果表明该方法专属性好,灵敏度高,线性范围宽,测定结果准确可靠,适用于番茄红素中砷含量的测定.     

新上岗护士综合职业能力的调查分析

目的了解参加工作3年内新上岗护士综合职业能力的情况。方法采用自行设计问卷调查表,对参加工作3年内护士综合职业能力进行了调查。结果工作年限不同、学历结构不同其综合职业能力差异存在显著性(P<0.05);不同年龄组护士综合职业能力无差异(P>0.05)。结论加强新上岗护士综合职业能力的培养,对护理质量的提高将起到积极作用。     

数控机床造型的再设计

根据我国机床造型设计发展现状,提出了符合我国国情的机床产品造型再设计的观点.结合工业设计基本理论,通过色彩、形态、宜人性分析数控机床造型的优缺点,总结出数控机床造型设计原则,提出了切实可行的数控机床造型再设计方案.在此基础上,以两台数控车床为例进行了造型的再设计.     

Facile Fabrication of Povidone Iodine-Embedded Polytetrafluoroethylene Superhydrophobic Films with Improved Antiadhesive and Bactericidal Properties in Bacterial Environments

It remains a challenge to maintain the antiadhesion properties of superhydrophobic films after exposure to bacterial environments. In this work, superhydrophobic bactericidal polymer films via the simple incorporation of polyvinylpyrrolidone-iodine (PVP-I) or iodine into polytetrafluoroethylene (PTFE) are fabricated to improve their antiadhesive and antibacterial capability. Superhydrophobic iodine-embedded films, polytetrafluoroethylene/polyvinylpyrrolidone-iodine and polytetrafluoroethylene-iodine (PTFE/PVP-I and PTFE-I), show excellent antiadhesive and bactericidal performances even post exposure to bacterial solutions as compared to iodine-free counterparts by controlling the release of iodine. Especially, superhydrophobic PTFE/PVP-I films display a more sustained iodine release profile and significant antibacterial properties against gram-positive (S. aureus, methicillin-resistant S. aureus (MRSA)) and gram-negative (E. coli) bacteria. Such a facile combination of antiseptic agents and superhydrophobic surface could be widely used for antiseptic biomedical applications.     

Preparation of V doped lanthanum silicate electrolyte ceramics by combustion method and study on conductance mechanism

Vanadium doped La_9.33Si_6−xV_xO_26+0.5x (x = 0.5, 1.0, 1.5) (LSVO) electrolyte powder was prepared by combustion method at 600°C for 5-7 min. The powder was sintered at 1500°C for 3 hours to prepare LSVO ceramics. XPS, IR, XRD, and EIS analysis show that V⁵⁺ doping replaces Si⁴⁺ in [SiO₄] to form [Si(V)O₄] tetrahedron. With the increase in x, the lattice volume increase. When x = 2.0, the LaVO₄ phase was formed, indicating that the limit doping amount of V⁵⁺ replacing Si⁴⁺ is x ≤ 1.5. The conductivity of LSVO increases significantly with the increase in x (x ≤ 1.0), which attributed to the defect reaction caused by V⁵⁺ doping. The addition of the interstitial oxygen Oi* in 6₃ channels and the increase of lattice volume leads to increased conductivity. When x = 1.0, the highest conductivity is 1.46 × 10⁻² S·cm⁻¹ (800°C). The doping enhancement conductivity mechanism is the Interstitial oxygen defect-Lattice volume composite enhancement mechanism.     

Influence of forming method of blending versus casting layer-by-layer on structural properties and packing performances of casein-gelatin composite edible film under different appending proportion

In order to obtain casein edible films with great packing performance, gelatin as the reinforcing additive with different ratios were loaded via two methods including layer- by- layer and blending. A comparative study on structure properties between double layers and blending films made from casein and gelatin was obtained by scanning electron microscopy and Fourier transform infrared spectroscopy. The difference between the films' packing characters were conducted by water vapor permeability (WVP), optical property, and mechanical properties (including tensile strength (TS) and elongation (EAB)). The results showed that the degree of films roughness increased and the structural stability decreased as the increase of gelatin additive ratio in both double layers and blending films. Thickness and WVP both displayed a trend of increasing first then decreasing at the dividing of gelatin instead of casein in 50%. Importantly, WVP values in double layers film with a largest value of 6.95 gm⁻¹Pa⁻¹s⁻¹ was higher than blending films, observably (P < 0.05). Additionally, TS in blending film was increased by 23.44% than double layers film under the gelatin additive proportion of 70%, and EAB value in double layers film was larger by 207.65% than blending film under the gelatin additive proportion of 10%.     

活性炭去除氦气中CH4和N2杂质的性能研究

旨在有效去除氦气中存在的甲烷和氮气杂质组分,通过对活性炭77 K下N2吸附脱附等温线测试,比较不同活性炭的结构性能,选择性能较优的活性炭AC-1吸附材料,测试了吸附剂在不同温度下对甲烷和氮气的吸附性能.采用氢氧化钠溶液对活性炭AC-1进行了表面改性,研究了改性活性炭对甲烷和氮气的吸附性能.结果表明:不同温度时活性炭AC...     

Medium-entropy (Ti,Zr, Hf)2SC MAX phase

Medium- and high-entropy alloys or ceramics for tuning the physicochemical properties of materials by the combination of multiple principal elements have received much interest. Herein, a medium-entropy (Ti, Zr, Hf)₂SC phase was synthesized attributing to the structural and chemical diversity of MAX phases. The crystal structure of (Ti, Zr, Hf)₂SC was determined by the Rietveld refinement of XRD, SEM, and atom-resolved TEM along with EDS elemental analysis. Phase evolution of X-ray diffraction patterns and TG/DSC curves were employed to reveal the synthesis mechanism of (Ti, Zr, Hf)₂SC from 2TiC–Zr–ZrC-2HfH₂-3.2FeS reactant system. The Vicker's hardness and the electrical resistivity of (Ti, Zr, Hf)₂SC were found higher than those of Ti₂SC, but the thermal conductivity of (Ti, Zr, Hf)₂SC was lower.     

清涧河流域不同水土保持措施配置下蓄水拦沙效益分析

从分析清涧河流域不同年代水土保持措施配置人手,以蓄水拦沙效益为研究目标,探讨了水土保持措施优化配置问题。分析认为：水土保持措施配置与蓄水拦沙效益是密切相关的,淤地坝在水土保持措施配置中应占有合理比重,坡面治理措施配置中需进一步加大封禁治理比例。     

页岩气井脆性页岩井壁裂缝扩展机理

页岩钻井中井壁失稳是制约页岩气大规模开发的关键技术难题。阐述了页岩井壁稳定技术现状和存在的问题,借助固体力学、断裂力学和界面化学理论,建立了介质润湿特性控制的裂缝扩展模型,提出了基于润湿理论的页岩井壁稳定评价方法。研究结果表明,页岩地层钻井时水基钻井液应减小钻井液界面张力和增大钻井液与岩石的润湿角;油基钻井液应减小钻井液界面张力和润湿角,从而强化井壁围岩强度、防止页岩井壁发生垮塌。页岩地层井壁稳定性尺度效应明显,不同尺度条件下井壁围岩裂缝扩展机制各异。探索不同尺度条件下页岩井壁围岩失稳机制,对页岩气井钻井液设计具有重要的意义。