The Impacts of Crystalline Structure and Different Surface Functional Groups on Drug Release and the Osseointegration Process of Nanostructured TiO2

In implantable materials, surface topography and chemistry are the most important in the effective osseointegration and interaction with drug molecules. Therefore, structural and surface modifications of nanostructured titanium dioxide (TiO₂) layers are reported in the present work. In particular, the modification of annealed TiO₂ samples with —OH groups and silane derivatives, confirmed by X-ray photoelectron spectroscopy, is shown. Moreover, the ibuprofen release process was studied regarding the desorption-desorption-diffusion (DDD) kinetic model. The results proved that the most significant impact on the release profile is annealing, and further surface modifications did not change its kinetics. Additionally, the cell adhesion and proliferation were examined based on the MTS test and immunofluorescent staining. The obtained data showed that the proposed changes in the surface chemistry enhance the samples’ hydrophilicity. Moreover, improvements in the adhesion and proliferation of the MG-63 cells were observed.     

(Sm0.5Gd0.2Nd0.3)2(Hf0.3Ce0.7)2O7复合氧化物的热物理性能

为寻求新型热障涂层用陶瓷材料,本文采用高温固相烧结法制备了(Sm_0.5Gd_0.2Nd_0.3)₂(Hf_0.3Ce_0.7)₂O₇复合氧化物。利用XRD分析了其晶体结构,SEM分析其显微组织,膨胀仪测试其热膨胀性能,激光热导仪测试其热扩散系数。结果表明,成功制备了具有单一萤石晶体结构的(Sm_0.5Gd_0.2Nd_0.3)₂(Hf_0.3Ce_0.7)₂O₇复合氧化物。其显微组织结构致密,晶界清晰无其他相存在。由于复杂的元素组成和较大的原子量,其热导率明显低于7YSZ和Sm₂Ce₂O₇。其较低的热膨胀系数则归因于B位离子较小的离子半径,但其热膨胀系数依然满足热障涂层的要求。     

Y3+/Li+和Y3+/Na+双掺杂氟化钡快响应闪烁晶体

氟化钡(BaF₂)晶体是已知响应最快的闪烁晶体,在高能物理、核物理及核医学等领域有着广泛的应用前景。抑制BaF₂晶体的慢发光成分对其工程应用至关重要。本文利用坩埚下降法制备了高Y³⁺掺杂浓度5%、8%、10%(摩尔分数)的BaF₂晶体,并采用Y³⁺与碱金属离子(Li⁺、Na⁺)共掺杂的方法形成电荷补偿阻止间隙F^-的产生,制备了双掺杂型BaF₂快响应闪烁晶体,进而基于优化的5 ns和2 500 ns时间门宽测试方法,研究了Y³⁺掺杂浓度以及Y³⁺与碱金属离子(Li⁺、Na⁺)共掺杂浓度对BaF₂闪烁晶体快/慢成分比的影响规律。结果表明,生长的高浓度Y³⁺掺杂BaF₂晶体的光学质量优异,在220 nm和300 nm处透过率分别高于90%和92%;随着Y³⁺掺杂浓度由0提高至10%,BaF₂晶体的慢发光成分显著降低,快/慢成分比由0.15提高至1.21;生长的Y³⁺/Li⁺及Y³⁺/Na⁺共掺杂BaF₂晶体的慢发光成分较Y³⁺掺杂BaF₂晶体进一步降低,快/慢成分比最高分别可达1.63和1.61。研制的双掺杂BaF₂快响应闪烁晶体有望应用于高能物理、核物理前沿实验等重要领域。     

9-(4-溴丁基)-9H-咔唑的相转移催化合成、表征及室温磷光性能研究——推荐一个大学化学综合实验

推荐了一个大学化学综合实验"9-(4-溴丁基)-9H-咔唑的相转移催化合成、表征及室温磷光性能研究"。实验利用相转移催化合成9-(4-溴丁基)-9H-咔唑分子,采用核磁共振、高分辨质谱和红外光谱对其分子结构进行表征,并利用紫外-可见吸收光谱、稳态/瞬态荧光光谱和密度泛函(DFT)理论计算对其室温磷光性能进行研究。本综合实验涵盖了有机化学、分析化学、物理化学、仪器分析以及理论化学的知识点,建议纳入化学专业高年级综合实验课程。     

Experimental and numerical simulation of effects of CO2/N2 concentration and initial temperature on combustion characteristics of biomass syngas

Biomass syngas is a form of renewable energy with very broad application prospects, and it has different combustion characteristics according to the fuel composition and processing technology of biomass syngas. The influence of combustion composition, diluent and temperature variation on combustion characteristics were studied in this paper. The FFCM-1 mechanism was used to investigate the combustion characteristics of CO/CH₄/H₂ under varied diluents CO₂/N₂ and temperature by using spherical expansion flame method and ANSYS CHEMKIN-PRO. The experimental laminar burning velocity was compared with the simulation results of FFCM-1 mechanism. The results reveal that the experimental data are in good agreement with the simulation results, which are somewhat different under the condition of rich fuel. The laminar burning velocity decreases significantly with the increase of diluent CO₂/N₂, with the effect of diluent CO₂ being more significant. The laminar burning velocity increase dramatically with the increase of initial temperature, and the adiabatic flame temperature also decreases with the increase of diluent. The reduction caused by diluent CO₂ is much larger than that caused by diluent N₂. The change of initial temperature also affects the adiabatic flame temperature, but the range of variation is not as pronounced as that of diluent. Not only was the interaction between the combustion characteristics of CO/CH₄/H₂ under different diluents and temperature changes explored in this paper, but the influence mechanism was also revealed in depth.     

Site Occupancies,Electron–Vibration Interaction and Energy Transfer of CaMgSi2O6: Eu2+, Mn2+ Phosphors for Potential Temperature-Sensing and Anti-counterfeiting Applications

Eu²⁺-, Mn²⁺- and Eu²⁺−Mn²⁺-doped CaMgSi₂O₆ phosphors have been prepared by a high-temperature solid-state reaction. Systematic investigation of the concentration- and temperature-dependent luminescence of Mn²⁺ showed that Mn²⁺ ions occupy two distinct sites in CaMgSi₂O₆. Electron–vibration interaction (EVI) analyses of Mn²⁺ ions revealed Huang–Rhys factors of 4.73 and 2.82 as well as effective phonon energies of 313 and 383 cm⁻¹ for the two sites. Eu²⁺−Mn²⁺ energy transfer is also discussed, and its efficiency is estimated by lifetime and luminescence spectra. The different thermal quenching behaviours of Eu²⁺ and Mn²⁺, the distinct emission colours of Eu²⁺ (blue, band peak at ∼451 nm) and Mn²⁺ (yellow–red range, band peaks at ∼583 and 693 nm) endow the co-doped samples with potential applications in luminescence thermometry and temperature-/excitation wavelength-responsive dual anti-counterfeiting.     

Effect of pressure on the low-temperature reaction of ethylene with N2O4

Calorimetric monitoring of the autoclave reaction N₂O₄ + C₂H₄ at –85 to +10 °C under argon pressure 10–30 bar revealed that the exothermic chemical reaction started at temperatures above –52 °C at 10 bar, whereas an intensive exothermic reaction started at –85 °C and pressure of 30 bar. IR study showed that oligo/polynitroethylene was formed at 30 bar, while carbonyl and hydroxy compound as well as nitrate R–ONO₂ formation occurred upon processing at 10 bar.     

新型BT-BMT-xBNT无铅高储能密度陶瓷研究

本文采用传统固相反应法,成功制备了新型无铅弛豫铁电陶瓷(1-x)[0.9BaTiO₃-0.1Bi(Mg_0.25Ta_0.5)O₃]-xBi_0.5Na_0.5TiO₃。结果表明,较高居里温度的Bi_0.5Na_0.5TiO₃的引入,使得材料体系中建立了更多的以Bi—O耦合为主的极性纳米区域,弥补了因Bi(Mg_0.25Ta_0.5)O₃的加入导致的宏观极化强度的减少,提高了材料的饱和极化强度,实现了较高储能密度的同时具有更好的温度稳定性。在245 kV/cm电场强度下,x=0.2样品的储能密度约为4.01 J/cm³,储能效率约为84.86%,同时该组分在20~170 ℃储能密度的变化率小于5%,储能效率的变化率小于6%,表现出优异的温度稳定性。     

Influence of staff number and internal constellation on surgical site infection in an operating room

Prediction of bacteria-carrying particle （BCP） dispersion and particle distribution released from staffmem- bers in an operating room （OR） is very important for creating and sustaining a safe indoor environment. Postoperative wound infections cause significant morbidity and mortality, and contribute to increased hospitalization time. Increasing the number of personnel within the OR disrupts the ventilation airflow pattern and causes enhanced contamination risk in the area of an open wound. Whether the amount of staffwithin the OR influences the BCP distribution in the surgical zone has rarely been investigated. This study was conducted to explore the influence of the number of personnel in the OR on the airflow field and the BCP distribution. This was performed by applying a numerical calculation to map the airflow field and Lagrangian particle tracking （LPT） for the BCP phase. The results are reported both for active sampling and passive monitoring approaches. Not surprisingly, a growing trend in the BCP concentration （cfu/ms） was observed as the amount of staff in the OR increased. Passive sampling shows unpredictable results due to the sedimentation rate, especially for small particles （5-10 i~m）. Risk factors for surgical site infections （SSls） must be well understood to develop more effective prevention programs.     

Effect of weighting materials on carbonation of oil well cement-based composites under high temperature and CO2-rich environment

As an indispensable part of cement slurry for high temperature and high pressure oil and gas wells, weighting materials have a significant impact on the carbon dioxide corrosion of oil well cement-based composites.This paper studied the carbonation process of cement with three weighting agents, and evaluated the compressive strength and carbonation depth of cement at 150 ℃. XRD, SEM and MIP were used to study the carbonation mechanism of cement. When 21 days of carbonation, the carbonation depth growth rate of hausmannite cement was 0.21 mm/d, hematite cement was 0.24 mm/d, and barite cement was 0.31 mm/d. The compressive strength of cement decreased after carbonation,and the carbonation had a minor influence on the compressive strength of hausmannite cement and the most significant impact on barite cement. The carbonation product of oil well cement was mainly calcite. Unstable vaterite mainly existed in the barite cement sample, indicating that the barite cement sample was the most serious corrosion. In the carbonation zone, the number of pores smaller than 10 nm increased the most in the hausmannite cement sample. Pores with a diameter greater than 100 nm accounted for 1.9 % in the hausmannite cement, 3.0 % in hematite cement, and 4.8 % in barite cement. The result shows that hausmannite is the most conducive to the corrosion resistance of oil well cement.