实现了以c切Nd:YVO4晶体作为激光增益介质,b切KGW和a切YVO4为拉曼晶体的半导体泵浦主动调Q双频移同步振荡的拉曼激光器的高效运转,得到YVO4晶体在890 cm−1处1178 nm和KGW晶体在901 cm−1处1180 nm的一阶斯托克斯光的双波长同步脉冲输出,...实现了以c切Nd:YVO4晶体作为激光增益介质,b切KGW和a切YVO4为拉曼晶体的半导体泵浦主动调Q双频移同步振荡的拉曼激光器的高效运转,得到YVO4晶体在890 cm−1处1178 nm和KGW晶体在901 cm−1处1180 nm的一阶斯托克斯光的双波长同步脉冲输出,当入射泵浦功率为8.37 w,脉冲重复率为15 kHz时,由1178和1180 nm光组成的拉曼激光平均输出最高为1.45 w。The efficient operation of a semiconductor-pumped actively Q-switched dual-frequency-shifted synchronous oscillation Raman laser was successfully demonstrated, employing a c-cut Nd:YVO4 crystal as the laser gain medium in conjunction with b-cut KGW and a-cut YVO4 crystals serving as Raman crystals. The synchronous dual wavelength pulse output of 1178 and 1180 nm first-order Stokes light corresponding to 890 cm−1 Raman shift in YVO4 and 901 cm−1 Raman shift in KGW is obtained. When the incident pump power is 8.37 w and the PRF is 15 kHz, the average output Raman laser composed of 1178 and 1180 nm lines is 1.45 w.展开更多
A2/O + MBR工艺为A2/O工艺与MBR工艺的串联组合,利用了MBR膜池代替A2/O工艺中的二沉池,使其具有更小的占地面积和更加优质、稳定的出水水质保障。为了探究传统A2/O工艺及A2/O + MBR工艺在城镇污水处理中的应用效能,在同季节、同时段、...A2/O + MBR工艺为A2/O工艺与MBR工艺的串联组合,利用了MBR膜池代替A2/O工艺中的二沉池,使其具有更小的占地面积和更加优质、稳定的出水水质保障。为了探究传统A2/O工艺及A2/O + MBR工艺在城镇污水处理中的应用效能,在同季节、同时段、进水均匀分配的条件下,比较分析了两种工艺在连续31 d中对污染物的降解效能。结果表明:A2/O + MBR工艺在处理城镇生活污水的效果上优于传统A2/O工艺,且抗冲击负荷能力更强,是更具优势的成熟工艺。A2/O工艺、A2/O + MBR工艺的平均处理成本分别为0.4702元/m3、0.6354元/m3,传统A2/O工艺运行成本比A2/O + MBR工艺低0.1652元/m3,相较之下更具经济性。The A2/O + MBR process is a series combination of A2/O process and MBR process. The MBR membrane tank is used to replace the secondary sedimentation tank in the A2/O process, so that it has a smaller floor area and better quality and stable effluent quality assurance. In order to explore the application efficiency of traditional A2/O process and A2/O + MBR process in urban sewage treatment, the degradation efficiency of pollutants by the two processes in 31 days was compared and analyzed under the condition of uniform distribution of water in the same season and at the same time. The results show that the A2/O + MBR process is superior to the traditional A2/O process in the treatment of urban domestic sewage, and the impact load resistance is stronger, which is a more advantageous mature process. The average treatment costs of theA2/O process and the A2/O + MBR process are 0.4702 yuan/m3 and 0.6354 yuan/m3, respectively. The operating cost of the traditional A2/O process is 0.1652 yuan/m3 lower than that of the A2/O + MBR process, which is more economical.展开更多
目的:探讨贝叶斯正则化似然(BPL)重建算法在不同呼吸状态下对18F-FDG PET/CT肺结节半定量参数的影响。方法:回顾性分析2022年6月至2022年10月间于青岛大学附属医院行18F-FDG PET/CT全身扫描的108例患者,共计139个肺结节。采用自由呼吸O...目的:探讨贝叶斯正则化似然(BPL)重建算法在不同呼吸状态下对18F-FDG PET/CT肺结节半定量参数的影响。方法:回顾性分析2022年6月至2022年10月间于青岛大学附属医院行18F-FDG PET/CT全身扫描的108例患者,共计139个肺结节。采用自由呼吸OSEM、自由呼吸BPL、屏气OSEM和屏气BPL重建算法对肺结节PET图像进行重建,比较组间最大标准摄取值(SUVmax)、平均标准摄取值(SUVmean)、峰值标准摄取值(SUVpeak)、信号/本底比值(SBR)等半定量参数。组间差异采用Wilcoxon秩和检验比较分析。结果:屏气OSEM组重建后摄取代谢参数SUVmax、SUVmean、SUVpeak和SBR高于自由呼吸OSEM组,分别是4.65 (2.38, 7.47)和3.02 (1.67, 5.61) (z = −9.53, p Objective: To investigate the impact of the Bayesian Penalized Likelihood (BPL) reconstruction algorithm on the semi-quantitative parameters of lung nodules in 18F-FDG PET/CT under different respiratory states. Methods: A retrospective analysis was conducted on 108 patients with a total of 139 lung nodules who underwent 18F-FDG PET/CT whole-body scans at the Affiliated Hospital of Qingdao University from June 2022 to October 2022. PET images of lung nodules were reconstructed using four algorithms: free-breathing OSEM, free-breathing BPL, breath-hold OSEM, and breath-hold BPL. The semi-quantitative parameters, including maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean), peak standardized uptake value (SUVpeak), and signal-to-background ratio (SBR), were compared among the groups. Intergroup differences were analyzed using the Wilcoxon rank-sum test. Results: The SUVmax, SUVmean, SUVpeak, and SBR values in the breath-hold OSEM group were higher than those in the free-breathing OSEM group, with values of 4.65 (2.38, 7.47) vs. 3.02 (1.67, 5.61) (z = −9.53, p < 0.001), 2.71 (1.85, 3.56) vs. 2.25 (1.36, 3.12) (z = −8.67, p < 0.001), 2.65 (1.38, 5.52) vs. 2.05 (1.29, 4.01) (z = −7.75, p < 0.001), and 3.02 (1.45, 5.32) vs. 1.77 (1.01, 3.50) (z = −9.74, p < 0.001), respectively. The SUVmax, SUVmean, SUVpeak, and SBR values in the breath-hold BPL group were higher than those in the free-breathing BPL group, with values of 6.8 (3.51, 11.55) vs. 4.45 (2.19, 7.31) (z = −9.99, p < 0.001), 3.42 (2.52, 4.91) vs. 2.71 (1.68, 3.55) (z = −9.30, p < 0.001), 3.70 (2.07, 6.61) vs. 2.69 (1.72, 5.27) (z = −9.30, p < 0.001), and 4.44 (2.24, 7.61) vs. 2.59 (1.28, 4.66) (z = −10.07, p < 0.001), respectively. The SUVmax, SUVmean, SUVpeak, and SBR values in the BPL groups were higher than those in the OSEM groups under both breath-hold and free-breathing conditions (all p < 0.001). The breath-hold BPL group had a significantly greater impact on the metabolic parameters (SUVmax, SUVmean, SUVpeak, and SBR) and their changes (%ΔSUVmax, %ΔSUVmean, %ΔSUVpeak, and %ΔSBR) compared to the free-breathing BPL group (p < 0.001). Conclusion: The breath-hold BPL reconstruction algorithm reduces respiratory motion artifacts, significantly enhancing the detection rate of semi-quantitative parameters in PET images of pulmonary nodules, thereby providing a more precise imaging basis for the diagnosis of their benign or malignant nature.展开更多
在全球气候背景下,气象因素对PM2.5和O3污染的影响日益突出。量化气象及排放变化对PM2.5和O3污染的影响,对明确城市大气污染成因、科学指导下一步大气污染防治工作具有重要的现实意义。本文综述了气象条件和污染减排对PM2.5和O3污染影...在全球气候背景下,气象因素对PM2.5和O3污染的影响日益突出。量化气象及排放变化对PM2.5和O3污染的影响,对明确城市大气污染成因、科学指导下一步大气污染防治工作具有重要的现实意义。本文综述了气象条件和污染减排对PM2.5和O3污染影响的常用定量研究方法以及各类方法优缺点,以期为大气环境管理决策提供科学参考。In the context of global climate change, the influence of meteorological conditions on PM2.5 and O3 pollution has become increasingly prominent. Quantifying the effects of meteorological and emission changes on PM2.5 and O3 pollution was crucial for understanding the causes of urban air pollution and for scientifically guiding future air pollution control efforts. This paper reviewed commonly used research methods for assessing the impacts of meteorological conditions and pollution reduction on PM2.5 and O3 pollution, along with the strengths and weaknesses of various methods, aiming to support for environmental management decisions.展开更多
在探索高效二氧化碳(CO2)还原光催化剂的研究中,铂(Pt)掺杂策略因其显著的催化增强效应而受到广泛关注。本研究采用光化学沉积法成功制备了Pt掺杂的ZnIn2S4纳米花结构,通过X射线衍射(XRD)表征证实了Pt的成功掺杂。实验结果表明,Pt的引...在探索高效二氧化碳(CO2)还原光催化剂的研究中,铂(Pt)掺杂策略因其显著的催化增强效应而受到广泛关注。本研究采用光化学沉积法成功制备了Pt掺杂的ZnIn2S4纳米花结构,通过X射线衍射(XRD)表征证实了Pt的成功掺杂。实验结果表明,Pt的引入显著优化了材料的界面电荷转移特性。在最优Pt掺杂量条件下,ZnIn2S4光催化剂的CO2还原性能达到20.7 µmol∙g−1∙h−1,是原始性能的3.1倍。通过多种表征手段的系统研究,发现Pt的引入不仅显著增强了ZnIn2S4的可见光吸收能力和光响应范围,还促进了光生载流子的分离和转移,并有效抑制了电子–空穴的复合。这为开发基于Pt掺杂的高效光催化剂提供了新的机遇和思路,有望推动光催化领域的创新和发展。In studies exploring efficient carbon dioxide (CO2) reduction photocatalysts, the platinum (Pt)-doping strategy has attracted much attention due to its remarkable catalytic enhancement effect. In this study, Pt-doped ZnIn2S4 nanoflower structures were successfully prepared by photochemical deposition, and the successful doping of Pt was confirmed by X-ray diffraction (XRD) characterization. Experimental results show that the introduction of Pt significantly optimizes the interfacial charge transfer properties of the material. Under the condition of optimal Pt doping, the CO2 reduction performance of ZnIn2S4 photocatalyst reached 20.7 µmol∙g−1∙h−1, which is 3.1 times of the original performance. A systematic study by multiple characterization means reveals that the introduction of Pt not only significantly enhances the visible light absorption capacity and photoresponse range of ZnIn2S4, but also promotes the separation and transfer of photogenerated carriers, and effectively inhibits the electron-hole complexation. This provides new opportunities and ideas for the development of efficient photocatalysts based on Pt doping, which is expected to promote the innovation and development of photocatalysis.展开更多
Bi₂Se₃作为一种典型的拓扑绝缘体材料,具有独特的晶体结构和优异的光电特性,与传统导体和绝缘体不同,Bi₂Se₃在强自旋轨道耦合作用下,其表面存在特殊的量子态,不同自旋的电子呈反向运动,在众多材料中脱颖而出,近年来已成为新型光电材料...Bi₂Se₃作为一种典型的拓扑绝缘体材料,具有独特的晶体结构和优异的光电特性,与传统导体和绝缘体不同,Bi₂Se₃在强自旋轨道耦合作用下,其表面存在特殊的量子态,不同自旋的电子呈反向运动,在众多材料中脱颖而出,近年来已成为新型光电材料领域的研究热点,广泛应用于光电探测、太阳能电池等众多光电子领域,因此对Bi2Se3的光电特性进行深入探究具有重要意义,基于此本文综述了Bi₂Se₃材料在光电领域的研究进展,详细阐述了其在光电探测器、太阳能电池、非线性光学和自旋光电子学四个层面所展现的独特性能,并对未来Bi₂Se₃在光电子领域的应用与研究进行了展望。As a typical topological insulator material, Bi₂Se₃ has a unique crystal structure and excellent optoelectronic properties, different from traditional conductors and insulators, Bi₂Se₃ has a special quantum state on its surface under the strong spin-orbit coupling, and the electrons of different spins are in reverse motion, which stands out among many materials, and in recent years, it has become a research hotspot in the field of new optoelectronic materials, and is widely used in many optoelectronic fields such as photoelectric detection and solar cells. Therefore, it is of great significance to conduct an in-depth exploration of the photoelectric characteristics of Bi₂Se₃. In this paper, the research progress of Bi₂Se₃ materials in the field of optoelectronics is reviewed, and its unique properties in photodetectors, solar cells, nonlinear optics and spin optoelectronics are elaborated, and the future application and research of Bi₂Se₃ in the field of optoelectronics are prospected.展开更多
为了满足钕铁硼磁体在高温下运作的需求,减少磁体产生的涡流损耗,本文以夹层的方式制备了高电阻率的SmF3/NdF3复合钕铁硼磁体,探究了SmF3/NdF3复合粉添加量和比例对于钕铁硼磁体的电阻率、磁性能及力学性能的影响。研究表明,当SmF3/NdF...为了满足钕铁硼磁体在高温下运作的需求,减少磁体产生的涡流损耗,本文以夹层的方式制备了高电阻率的SmF3/NdF3复合钕铁硼磁体,探究了SmF3/NdF3复合粉添加量和比例对于钕铁硼磁体的电阻率、磁性能及力学性能的影响。研究表明,当SmF3/NdF3比例为3:1时,随着添加量的增加,磁体夹层的厚度提高,电阻率增大,磁能积和抗弯强度呈现下降趋势。当单位面积添加量达到6.52 × 10−4 g/mm2时,磁体电阻率增大到6.12 mΩ·cm,较未夹层的钕铁硼磁体电阻率146 μΩ·cm提高了一个数量级,但是磁体的最大磁能积和抗弯强度分别下降到39.61 MGOe/164 MPa;当保持夹层添加量不变,随着复合夹层中SmF3占比减小,夹层粉体逸散现象减弱,磁体的电阻率增大,当复合夹层SmF3/NdF3比例为1:5时电阻率最高,为24.3 mΩ·cm;当复合夹层SmF3/NdF3比例为1:1时,磁体的磁能积最高为43.91 MGOe,复合SmF3/NdF3的比例对磁体的抗弯强度影响并不相同,当复合夹层SmF3/NdF3比例为3:1时抗弯强度提高到了270 MPa,较无夹层钕铁硼磁体抗弯强度254 MPa提高了6%。To meet the operational requirements of NdFeB magnets under high-temperature conditions and mitigate eddy current losses, this study fabricates high-resistivity SmF3/NdF3 composite NdFeB magnets via a laminated structure. The effects of SmF3/NdF3 composite powder contents and stoichiometric ratios on resistivity, magnetic properties, and mechanical performance were systematically investigated. Results demonstrate that at a SmF3/NdF3 ratio of 3:1, increasing additive contents enhances interlayer thickness and resistivity of the magnets, reaching 6.12 mΩ·cm when the additive content achieves 6.52 × 10−4 g/mm2. While the magnetic energy product (BH)max was reduced to 39.61 MGOe and flexural strength to 164 MPa. Notably, the achieved resistivity of 6.12 mΩ·cm represents a one-order-of-magnitude improvement compared to non-laminated NdFeB magnets, which exhibit a resistivity of 146 μΩ·cm. Under constant interlayer additive content, the reduction of SmF3 proportion in the composite interlayer mitigates powder dispersion phenomena and enhances interlayer density, leading to increased resistivity. The resistivity reaches its maximum value of 24.3 mΩ·cm at a SmF3/NdF3 ratio of 1:5. The magnetic energy product peaks at 43.91 MGOe for a 1:1 SmF3/NdF3 ratio. The influence of SmF3/NdF3 ratios on flexural strength exhibits distinct trends, with the SmF3/NdF3 ratio of 3:1 demonstrating optimal mechanical performance. Specifically, the flexural strength increases to 270 MPa at a 3:1 ratio, representing a 6% enhancement compared to non-laminated NdFeB magnets (254 MPa).展开更多
目的:检测γ-Fe2O3纳米粒表面油酸的残留量,考察油酸残留量对纳米粒磁共振T1造影效果的影响。方法:采用热分解法制备γ-Fe2O3纳米粒,使用mPEG-P取代γ-Fe2O3纳米粒表面的油酸,得到水溶性的γ-Fe2O3-PEG纳米粒,采用高效液相色谱法测定纳...目的:检测γ-Fe2O3纳米粒表面油酸的残留量,考察油酸残留量对纳米粒磁共振T1造影效果的影响。方法:采用热分解法制备γ-Fe2O3纳米粒,使用mPEG-P取代γ-Fe2O3纳米粒表面的油酸,得到水溶性的γ-Fe2O3-PEG纳米粒,采用高效液相色谱法测定纳米粒表面残留的油酸,并在7T磁共振成像仪下考察油酸残留量与纳米粒T1造影效果的关联。最后,对体外造影效果最优的样品进行了体内磁共振成像测试。结果:建立了油酸的高效液相色谱检测方法,油酸在10~400 μg/mL浓度范围内具有良好的线性关系(r2 = 1),平均回收率为99.86%。通过改变γ-Fe2O3与mPEG-P的投料比,得到γ-Fe2O3-PEG纳米粒表面油酸残留个数分别为100、83、56、33的样品。体外磁共振成像结果表明,油酸残留量较少的纳米粒拥有更好的T1加权成像性能。小鼠体内血管造影显示,本研究制备的γ-Fe2O3-PEG纳米粒与临床使用的钆类造影剂相比,拥有更好的血管成像效果。结论:本研究成果为热分解法制备的氧化铁纳米粒表面油酸的定量分析提供了一种有效的检测方法,以促进该类纳米粒在生物医学领域的应用。Objective: Detection of residual oleic acid on the surface of γ-Fe2O3 nanoparticles and investigation of its impact on magnetic resonance T1 imaging. Method: We prepared γ-Fe2O3 nanoparticles via thermal decomposition, with mPEG-P replacing the oleic acid on the surface of the nanoparticles to yield water-soluble γ-Fe2O3-PEG nanoparticles. The residual oleic acid on the surface of the nanoparticles was quantified using High-Performance Liquid Chromatography, and the relationship between the amount of residual oleic acid and the T1 contrast effect of the nanoparticles was investigated using a 7T magnetic resonance imaging system. Finally, the vivo magnetic resonance imaging of the sample exhibiting the optimal in vitro contrast effect was conducted. Results: We developed a High-Performance Liquid Chromatography method for the detection of oleic acid, demonstrating a strong linear correlation in the concentration range of 10~400 μg/mL (r² = 1) with an average recovery rate of 99.86%. By varying the ratio of γ-Fe2O3 to mPEG-P, samples with oleic acid on the surface of γ-Fe2O3-PEG nanoparticles were obtained, with respective counts of 100, 83, 56, and 33. In vitro magnetic resonance imaging demonstrated that nanoparticles with lower residual oleic acid exhibited enhanced T1-weighted imaging performance. In vivo vascular imaging in mice demonstrated that the γ-Fe2O3-PEG nanoparticles prepared in this study provided better imaging results compared to commercially available gadolinium-based contrast agents. Conclusions: This study presents an effective detection method for the quantitative analysis of oleic acid on the surface of iron oxide nanoparticles synthesized via a thermolytic approach, thereby facilitating the application of such nanoparticles in the biomedical field.展开更多
微纳米α-Al2O3是一种重要的功能材料,因其优异的硬度、耐磨性、耐腐蚀性和高热稳定性,在表面涂层领域得到了广泛应用。随着微纳米技术的发展,微纳米级α-Al2O3作为添加剂在各涂层体系中的应用得到了深入研究,显示出其能够显著改善涂层...微纳米α-Al2O3是一种重要的功能材料,因其优异的硬度、耐磨性、耐腐蚀性和高热稳定性,在表面涂层领域得到了广泛应用。随着微纳米技术的发展,微纳米级α-Al2O3作为添加剂在各涂层体系中的应用得到了深入研究,显示出其能够显著改善涂层性能的潜力。微纳米α-Al2O3颗粒具有较大的比表面积和表面活性,能够增强涂层的机械性能,如硬度和耐磨性,同时提高涂层的耐腐蚀性和耐高温性能。微纳米α-Al2O3也是一种极优良的改性材料,其与有机硅烷、树脂等材料复合改性,既能大幅提升转化膜的应用效果,对其稳定性和耐候性也有较大的促进作用。在金属表面涂层、陶瓷涂层以及复合材料涂层中,微纳米α-Al2O3添加剂被广泛用于提高涂层的使用寿命和稳定性。此外,它在电子器件、航天航空和汽车工业等高技术领域也展现了广阔的应用前景。未来,随着表面技术的发展,微纳米α-Al2O3无铬钝化领域的市场应用将大幅增长,与其他功能性材料的协同作用和复合材料开发也将成为研究的重点。Micro-nano α-Al2O3 is an important functional material, because of its excellent hardness, wear resistance, corrosion resistance and high thermal stability, has been widely used in the field of surface coating. With the development of micro-nano technology, the application of micro-nano α-Al2O3 as an additive in various coating systems has been deeply studied, showing its potential to significantly improve coating properties. Micro-nano α-Al2O3 particles have a large specific surface area and surface activity, which can enhance the mechanical properties of the coating, such as hardness and wear resistance, while improving the corrosion resistance and high temperature resistance of the coating. Micro-nano α-Al2O3 is also an excellent modified material, and its composite modification with organosilane, resin and other materials can greatly improve the application effect of conversion film, and also has a greater role in promoting its stability and weather resistance. In metal surface coatings, ceramic coatings and composite coatings, micro-nano α-Al2O3 additives are widely used to improve the service life and stability of coatings. In addition, it also shows broad application prospects in high-tech fields such as electronic devices, aerospace and automotive industries. In the future, with the development of surface technology, the market application of micro-nano α-Al2O3 chromium-free passivation will grow significantly, and the synergy with other functional materials and the development of composite materials will also become the focus of research.展开更多
酒糟是酿酒行业的主要副产物且年产量巨大,实现酒糟的资源化利用将有助于该行业可持续发展。为提高酒糟的资源化利用水平,开展了厌氧发酵酒糟产甲烷试验,并利用酒糟发酵后的残渣制备了生物炭,考察了该生物炭对CO2的吸附性能。结果表明,...酒糟是酿酒行业的主要副产物且年产量巨大,实现酒糟的资源化利用将有助于该行业可持续发展。为提高酒糟的资源化利用水平,开展了厌氧发酵酒糟产甲烷试验,并利用酒糟发酵后的残渣制备了生物炭,考察了该生物炭对CO2的吸附性能。结果表明,酒糟发酵过程中加入竹炭可提高甲烷产量,当竹炭与酒糟质量比为1:1时,甲烷产量可达462.7 mL/g,高于未掺杂竹炭的酒糟产甲烷量(388.8 mL/g)。投加竹炭后所制备的沼渣生物炭具有更佳的孔隙结构和更高的CO2吸附量,其比表面积较未投加竹炭的沼渣生物炭可提高159%,对CO2的吸附量提高了62.5%,达到34.75 mg/g。通过伪一级和伪二级动力学模型研究了生物炭对CO2的吸附,发现伪一级动力学模型能更好地描述生物炭对CO2的吸附,表明生物炭对CO2以物理吸附为主。Vinasse is the primary by-product of the liquor industry, and its annual output is substantial. The effective utilization of vinasse can significantly contribute to the sustainable development of the liquor industry. To enhance the utilization of vinasse, an experiment was conducted to perform anaerobic fermentation of vinasse for methane production, and biochar was prepared from the fermentation residue. The adsorption performance of the biochar for CO2 was investigated. The results indicated that the methane yield could be increased by incorporating bamboo biochar (BB) during the fermentation of vinasse. When the mass ratio of BB to vinasse was 1:1, the methane yield reached 462.7 mL/g, surpassing the yield obtained without the addition of BB, which was 388.8 mL/g. The vinasse residue biochar (VRB) produced with BB exhibited a superior pore structure and higher CO2 adsorption capacity compared to that produced without BB. The specific surface area of VRB prepared with BB was 159% greater than that of the biochar without BB, and the CO2 adsorption capacity increased by 62.5%, reaching 34.75 mg/g. The pseudo-first-order and pseudo-second-order kinetic models were employed to analyze the CO2 adsorption by biochar. It was found that the pseudo-first-order kinetic model more accurately described the CO2 adsorption on biochar, indicating that physical adsorption predominantly governs the CO2 uptake by biochar.展开更多
文摘实现了以c切Nd:YVO4晶体作为激光增益介质,b切KGW和a切YVO4为拉曼晶体的半导体泵浦主动调Q双频移同步振荡的拉曼激光器的高效运转,得到YVO4晶体在890 cm−1处1178 nm和KGW晶体在901 cm−1处1180 nm的一阶斯托克斯光的双波长同步脉冲输出,当入射泵浦功率为8.37 w,脉冲重复率为15 kHz时,由1178和1180 nm光组成的拉曼激光平均输出最高为1.45 w。The efficient operation of a semiconductor-pumped actively Q-switched dual-frequency-shifted synchronous oscillation Raman laser was successfully demonstrated, employing a c-cut Nd:YVO4 crystal as the laser gain medium in conjunction with b-cut KGW and a-cut YVO4 crystals serving as Raman crystals. The synchronous dual wavelength pulse output of 1178 and 1180 nm first-order Stokes light corresponding to 890 cm−1 Raman shift in YVO4 and 901 cm−1 Raman shift in KGW is obtained. When the incident pump power is 8.37 w and the PRF is 15 kHz, the average output Raman laser composed of 1178 and 1180 nm lines is 1.45 w.
文摘A2/O + MBR工艺为A2/O工艺与MBR工艺的串联组合,利用了MBR膜池代替A2/O工艺中的二沉池,使其具有更小的占地面积和更加优质、稳定的出水水质保障。为了探究传统A2/O工艺及A2/O + MBR工艺在城镇污水处理中的应用效能,在同季节、同时段、进水均匀分配的条件下,比较分析了两种工艺在连续31 d中对污染物的降解效能。结果表明:A2/O + MBR工艺在处理城镇生活污水的效果上优于传统A2/O工艺,且抗冲击负荷能力更强,是更具优势的成熟工艺。A2/O工艺、A2/O + MBR工艺的平均处理成本分别为0.4702元/m3、0.6354元/m3,传统A2/O工艺运行成本比A2/O + MBR工艺低0.1652元/m3,相较之下更具经济性。The A2/O + MBR process is a series combination of A2/O process and MBR process. The MBR membrane tank is used to replace the secondary sedimentation tank in the A2/O process, so that it has a smaller floor area and better quality and stable effluent quality assurance. In order to explore the application efficiency of traditional A2/O process and A2/O + MBR process in urban sewage treatment, the degradation efficiency of pollutants by the two processes in 31 days was compared and analyzed under the condition of uniform distribution of water in the same season and at the same time. The results show that the A2/O + MBR process is superior to the traditional A2/O process in the treatment of urban domestic sewage, and the impact load resistance is stronger, which is a more advantageous mature process. The average treatment costs of theA2/O process and the A2/O + MBR process are 0.4702 yuan/m3 and 0.6354 yuan/m3, respectively. The operating cost of the traditional A2/O process is 0.1652 yuan/m3 lower than that of the A2/O + MBR process, which is more economical.
文摘目的:探讨贝叶斯正则化似然(BPL)重建算法在不同呼吸状态下对18F-FDG PET/CT肺结节半定量参数的影响。方法:回顾性分析2022年6月至2022年10月间于青岛大学附属医院行18F-FDG PET/CT全身扫描的108例患者,共计139个肺结节。采用自由呼吸OSEM、自由呼吸BPL、屏气OSEM和屏气BPL重建算法对肺结节PET图像进行重建,比较组间最大标准摄取值(SUVmax)、平均标准摄取值(SUVmean)、峰值标准摄取值(SUVpeak)、信号/本底比值(SBR)等半定量参数。组间差异采用Wilcoxon秩和检验比较分析。结果:屏气OSEM组重建后摄取代谢参数SUVmax、SUVmean、SUVpeak和SBR高于自由呼吸OSEM组,分别是4.65 (2.38, 7.47)和3.02 (1.67, 5.61) (z = −9.53, p Objective: To investigate the impact of the Bayesian Penalized Likelihood (BPL) reconstruction algorithm on the semi-quantitative parameters of lung nodules in 18F-FDG PET/CT under different respiratory states. Methods: A retrospective analysis was conducted on 108 patients with a total of 139 lung nodules who underwent 18F-FDG PET/CT whole-body scans at the Affiliated Hospital of Qingdao University from June 2022 to October 2022. PET images of lung nodules were reconstructed using four algorithms: free-breathing OSEM, free-breathing BPL, breath-hold OSEM, and breath-hold BPL. The semi-quantitative parameters, including maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean), peak standardized uptake value (SUVpeak), and signal-to-background ratio (SBR), were compared among the groups. Intergroup differences were analyzed using the Wilcoxon rank-sum test. Results: The SUVmax, SUVmean, SUVpeak, and SBR values in the breath-hold OSEM group were higher than those in the free-breathing OSEM group, with values of 4.65 (2.38, 7.47) vs. 3.02 (1.67, 5.61) (z = −9.53, p < 0.001), 2.71 (1.85, 3.56) vs. 2.25 (1.36, 3.12) (z = −8.67, p < 0.001), 2.65 (1.38, 5.52) vs. 2.05 (1.29, 4.01) (z = −7.75, p < 0.001), and 3.02 (1.45, 5.32) vs. 1.77 (1.01, 3.50) (z = −9.74, p < 0.001), respectively. The SUVmax, SUVmean, SUVpeak, and SBR values in the breath-hold BPL group were higher than those in the free-breathing BPL group, with values of 6.8 (3.51, 11.55) vs. 4.45 (2.19, 7.31) (z = −9.99, p < 0.001), 3.42 (2.52, 4.91) vs. 2.71 (1.68, 3.55) (z = −9.30, p < 0.001), 3.70 (2.07, 6.61) vs. 2.69 (1.72, 5.27) (z = −9.30, p < 0.001), and 4.44 (2.24, 7.61) vs. 2.59 (1.28, 4.66) (z = −10.07, p < 0.001), respectively. The SUVmax, SUVmean, SUVpeak, and SBR values in the BPL groups were higher than those in the OSEM groups under both breath-hold and free-breathing conditions (all p < 0.001). The breath-hold BPL group had a significantly greater impact on the metabolic parameters (SUVmax, SUVmean, SUVpeak, and SBR) and their changes (%ΔSUVmax, %ΔSUVmean, %ΔSUVpeak, and %ΔSBR) compared to the free-breathing BPL group (p < 0.001). Conclusion: The breath-hold BPL reconstruction algorithm reduces respiratory motion artifacts, significantly enhancing the detection rate of semi-quantitative parameters in PET images of pulmonary nodules, thereby providing a more precise imaging basis for the diagnosis of their benign or malignant nature.
文摘在全球气候背景下,气象因素对PM2.5和O3污染的影响日益突出。量化气象及排放变化对PM2.5和O3污染的影响,对明确城市大气污染成因、科学指导下一步大气污染防治工作具有重要的现实意义。本文综述了气象条件和污染减排对PM2.5和O3污染影响的常用定量研究方法以及各类方法优缺点,以期为大气环境管理决策提供科学参考。In the context of global climate change, the influence of meteorological conditions on PM2.5 and O3 pollution has become increasingly prominent. Quantifying the effects of meteorological and emission changes on PM2.5 and O3 pollution was crucial for understanding the causes of urban air pollution and for scientifically guiding future air pollution control efforts. This paper reviewed commonly used research methods for assessing the impacts of meteorological conditions and pollution reduction on PM2.5 and O3 pollution, along with the strengths and weaknesses of various methods, aiming to support for environmental management decisions.
文摘在探索高效二氧化碳(CO2)还原光催化剂的研究中,铂(Pt)掺杂策略因其显著的催化增强效应而受到广泛关注。本研究采用光化学沉积法成功制备了Pt掺杂的ZnIn2S4纳米花结构,通过X射线衍射(XRD)表征证实了Pt的成功掺杂。实验结果表明,Pt的引入显著优化了材料的界面电荷转移特性。在最优Pt掺杂量条件下,ZnIn2S4光催化剂的CO2还原性能达到20.7 µmol∙g−1∙h−1,是原始性能的3.1倍。通过多种表征手段的系统研究,发现Pt的引入不仅显著增强了ZnIn2S4的可见光吸收能力和光响应范围,还促进了光生载流子的分离和转移,并有效抑制了电子–空穴的复合。这为开发基于Pt掺杂的高效光催化剂提供了新的机遇和思路,有望推动光催化领域的创新和发展。In studies exploring efficient carbon dioxide (CO2) reduction photocatalysts, the platinum (Pt)-doping strategy has attracted much attention due to its remarkable catalytic enhancement effect. In this study, Pt-doped ZnIn2S4 nanoflower structures were successfully prepared by photochemical deposition, and the successful doping of Pt was confirmed by X-ray diffraction (XRD) characterization. Experimental results show that the introduction of Pt significantly optimizes the interfacial charge transfer properties of the material. Under the condition of optimal Pt doping, the CO2 reduction performance of ZnIn2S4 photocatalyst reached 20.7 µmol∙g−1∙h−1, which is 3.1 times of the original performance. A systematic study by multiple characterization means reveals that the introduction of Pt not only significantly enhances the visible light absorption capacity and photoresponse range of ZnIn2S4, but also promotes the separation and transfer of photogenerated carriers, and effectively inhibits the electron-hole complexation. This provides new opportunities and ideas for the development of efficient photocatalysts based on Pt doping, which is expected to promote the innovation and development of photocatalysis.
文摘Bi₂Se₃作为一种典型的拓扑绝缘体材料,具有独特的晶体结构和优异的光电特性,与传统导体和绝缘体不同,Bi₂Se₃在强自旋轨道耦合作用下,其表面存在特殊的量子态,不同自旋的电子呈反向运动,在众多材料中脱颖而出,近年来已成为新型光电材料领域的研究热点,广泛应用于光电探测、太阳能电池等众多光电子领域,因此对Bi2Se3的光电特性进行深入探究具有重要意义,基于此本文综述了Bi₂Se₃材料在光电领域的研究进展,详细阐述了其在光电探测器、太阳能电池、非线性光学和自旋光电子学四个层面所展现的独特性能,并对未来Bi₂Se₃在光电子领域的应用与研究进行了展望。As a typical topological insulator material, Bi₂Se₃ has a unique crystal structure and excellent optoelectronic properties, different from traditional conductors and insulators, Bi₂Se₃ has a special quantum state on its surface under the strong spin-orbit coupling, and the electrons of different spins are in reverse motion, which stands out among many materials, and in recent years, it has become a research hotspot in the field of new optoelectronic materials, and is widely used in many optoelectronic fields such as photoelectric detection and solar cells. Therefore, it is of great significance to conduct an in-depth exploration of the photoelectric characteristics of Bi₂Se₃. In this paper, the research progress of Bi₂Se₃ materials in the field of optoelectronics is reviewed, and its unique properties in photodetectors, solar cells, nonlinear optics and spin optoelectronics are elaborated, and the future application and research of Bi₂Se₃ in the field of optoelectronics are prospected.
文摘为了满足钕铁硼磁体在高温下运作的需求,减少磁体产生的涡流损耗,本文以夹层的方式制备了高电阻率的SmF3/NdF3复合钕铁硼磁体,探究了SmF3/NdF3复合粉添加量和比例对于钕铁硼磁体的电阻率、磁性能及力学性能的影响。研究表明,当SmF3/NdF3比例为3:1时,随着添加量的增加,磁体夹层的厚度提高,电阻率增大,磁能积和抗弯强度呈现下降趋势。当单位面积添加量达到6.52 × 10−4 g/mm2时,磁体电阻率增大到6.12 mΩ·cm,较未夹层的钕铁硼磁体电阻率146 μΩ·cm提高了一个数量级,但是磁体的最大磁能积和抗弯强度分别下降到39.61 MGOe/164 MPa;当保持夹层添加量不变,随着复合夹层中SmF3占比减小,夹层粉体逸散现象减弱,磁体的电阻率增大,当复合夹层SmF3/NdF3比例为1:5时电阻率最高,为24.3 mΩ·cm;当复合夹层SmF3/NdF3比例为1:1时,磁体的磁能积最高为43.91 MGOe,复合SmF3/NdF3的比例对磁体的抗弯强度影响并不相同,当复合夹层SmF3/NdF3比例为3:1时抗弯强度提高到了270 MPa,较无夹层钕铁硼磁体抗弯强度254 MPa提高了6%。To meet the operational requirements of NdFeB magnets under high-temperature conditions and mitigate eddy current losses, this study fabricates high-resistivity SmF3/NdF3 composite NdFeB magnets via a laminated structure. The effects of SmF3/NdF3 composite powder contents and stoichiometric ratios on resistivity, magnetic properties, and mechanical performance were systematically investigated. Results demonstrate that at a SmF3/NdF3 ratio of 3:1, increasing additive contents enhances interlayer thickness and resistivity of the magnets, reaching 6.12 mΩ·cm when the additive content achieves 6.52 × 10−4 g/mm2. While the magnetic energy product (BH)max was reduced to 39.61 MGOe and flexural strength to 164 MPa. Notably, the achieved resistivity of 6.12 mΩ·cm represents a one-order-of-magnitude improvement compared to non-laminated NdFeB magnets, which exhibit a resistivity of 146 μΩ·cm. Under constant interlayer additive content, the reduction of SmF3 proportion in the composite interlayer mitigates powder dispersion phenomena and enhances interlayer density, leading to increased resistivity. The resistivity reaches its maximum value of 24.3 mΩ·cm at a SmF3/NdF3 ratio of 1:5. The magnetic energy product peaks at 43.91 MGOe for a 1:1 SmF3/NdF3 ratio. The influence of SmF3/NdF3 ratios on flexural strength exhibits distinct trends, with the SmF3/NdF3 ratio of 3:1 demonstrating optimal mechanical performance. Specifically, the flexural strength increases to 270 MPa at a 3:1 ratio, representing a 6% enhancement compared to non-laminated NdFeB magnets (254 MPa).
文摘目的:检测γ-Fe2O3纳米粒表面油酸的残留量,考察油酸残留量对纳米粒磁共振T1造影效果的影响。方法:采用热分解法制备γ-Fe2O3纳米粒,使用mPEG-P取代γ-Fe2O3纳米粒表面的油酸,得到水溶性的γ-Fe2O3-PEG纳米粒,采用高效液相色谱法测定纳米粒表面残留的油酸,并在7T磁共振成像仪下考察油酸残留量与纳米粒T1造影效果的关联。最后,对体外造影效果最优的样品进行了体内磁共振成像测试。结果:建立了油酸的高效液相色谱检测方法,油酸在10~400 μg/mL浓度范围内具有良好的线性关系(r2 = 1),平均回收率为99.86%。通过改变γ-Fe2O3与mPEG-P的投料比,得到γ-Fe2O3-PEG纳米粒表面油酸残留个数分别为100、83、56、33的样品。体外磁共振成像结果表明,油酸残留量较少的纳米粒拥有更好的T1加权成像性能。小鼠体内血管造影显示,本研究制备的γ-Fe2O3-PEG纳米粒与临床使用的钆类造影剂相比,拥有更好的血管成像效果。结论:本研究成果为热分解法制备的氧化铁纳米粒表面油酸的定量分析提供了一种有效的检测方法,以促进该类纳米粒在生物医学领域的应用。Objective: Detection of residual oleic acid on the surface of γ-Fe2O3 nanoparticles and investigation of its impact on magnetic resonance T1 imaging. Method: We prepared γ-Fe2O3 nanoparticles via thermal decomposition, with mPEG-P replacing the oleic acid on the surface of the nanoparticles to yield water-soluble γ-Fe2O3-PEG nanoparticles. The residual oleic acid on the surface of the nanoparticles was quantified using High-Performance Liquid Chromatography, and the relationship between the amount of residual oleic acid and the T1 contrast effect of the nanoparticles was investigated using a 7T magnetic resonance imaging system. Finally, the vivo magnetic resonance imaging of the sample exhibiting the optimal in vitro contrast effect was conducted. Results: We developed a High-Performance Liquid Chromatography method for the detection of oleic acid, demonstrating a strong linear correlation in the concentration range of 10~400 μg/mL (r² = 1) with an average recovery rate of 99.86%. By varying the ratio of γ-Fe2O3 to mPEG-P, samples with oleic acid on the surface of γ-Fe2O3-PEG nanoparticles were obtained, with respective counts of 100, 83, 56, and 33. In vitro magnetic resonance imaging demonstrated that nanoparticles with lower residual oleic acid exhibited enhanced T1-weighted imaging performance. In vivo vascular imaging in mice demonstrated that the γ-Fe2O3-PEG nanoparticles prepared in this study provided better imaging results compared to commercially available gadolinium-based contrast agents. Conclusions: This study presents an effective detection method for the quantitative analysis of oleic acid on the surface of iron oxide nanoparticles synthesized via a thermolytic approach, thereby facilitating the application of such nanoparticles in the biomedical field.
文摘微纳米α-Al2O3是一种重要的功能材料,因其优异的硬度、耐磨性、耐腐蚀性和高热稳定性,在表面涂层领域得到了广泛应用。随着微纳米技术的发展,微纳米级α-Al2O3作为添加剂在各涂层体系中的应用得到了深入研究,显示出其能够显著改善涂层性能的潜力。微纳米α-Al2O3颗粒具有较大的比表面积和表面活性,能够增强涂层的机械性能,如硬度和耐磨性,同时提高涂层的耐腐蚀性和耐高温性能。微纳米α-Al2O3也是一种极优良的改性材料,其与有机硅烷、树脂等材料复合改性,既能大幅提升转化膜的应用效果,对其稳定性和耐候性也有较大的促进作用。在金属表面涂层、陶瓷涂层以及复合材料涂层中,微纳米α-Al2O3添加剂被广泛用于提高涂层的使用寿命和稳定性。此外,它在电子器件、航天航空和汽车工业等高技术领域也展现了广阔的应用前景。未来,随着表面技术的发展,微纳米α-Al2O3无铬钝化领域的市场应用将大幅增长,与其他功能性材料的协同作用和复合材料开发也将成为研究的重点。Micro-nano α-Al2O3 is an important functional material, because of its excellent hardness, wear resistance, corrosion resistance and high thermal stability, has been widely used in the field of surface coating. With the development of micro-nano technology, the application of micro-nano α-Al2O3 as an additive in various coating systems has been deeply studied, showing its potential to significantly improve coating properties. Micro-nano α-Al2O3 particles have a large specific surface area and surface activity, which can enhance the mechanical properties of the coating, such as hardness and wear resistance, while improving the corrosion resistance and high temperature resistance of the coating. Micro-nano α-Al2O3 is also an excellent modified material, and its composite modification with organosilane, resin and other materials can greatly improve the application effect of conversion film, and also has a greater role in promoting its stability and weather resistance. In metal surface coatings, ceramic coatings and composite coatings, micro-nano α-Al2O3 additives are widely used to improve the service life and stability of coatings. In addition, it also shows broad application prospects in high-tech fields such as electronic devices, aerospace and automotive industries. In the future, with the development of surface technology, the market application of micro-nano α-Al2O3 chromium-free passivation will grow significantly, and the synergy with other functional materials and the development of composite materials will also become the focus of research.
文摘酒糟是酿酒行业的主要副产物且年产量巨大,实现酒糟的资源化利用将有助于该行业可持续发展。为提高酒糟的资源化利用水平,开展了厌氧发酵酒糟产甲烷试验,并利用酒糟发酵后的残渣制备了生物炭,考察了该生物炭对CO2的吸附性能。结果表明,酒糟发酵过程中加入竹炭可提高甲烷产量,当竹炭与酒糟质量比为1:1时,甲烷产量可达462.7 mL/g,高于未掺杂竹炭的酒糟产甲烷量(388.8 mL/g)。投加竹炭后所制备的沼渣生物炭具有更佳的孔隙结构和更高的CO2吸附量,其比表面积较未投加竹炭的沼渣生物炭可提高159%,对CO2的吸附量提高了62.5%,达到34.75 mg/g。通过伪一级和伪二级动力学模型研究了生物炭对CO2的吸附,发现伪一级动力学模型能更好地描述生物炭对CO2的吸附,表明生物炭对CO2以物理吸附为主。Vinasse is the primary by-product of the liquor industry, and its annual output is substantial. The effective utilization of vinasse can significantly contribute to the sustainable development of the liquor industry. To enhance the utilization of vinasse, an experiment was conducted to perform anaerobic fermentation of vinasse for methane production, and biochar was prepared from the fermentation residue. The adsorption performance of the biochar for CO2 was investigated. The results indicated that the methane yield could be increased by incorporating bamboo biochar (BB) during the fermentation of vinasse. When the mass ratio of BB to vinasse was 1:1, the methane yield reached 462.7 mL/g, surpassing the yield obtained without the addition of BB, which was 388.8 mL/g. The vinasse residue biochar (VRB) produced with BB exhibited a superior pore structure and higher CO2 adsorption capacity compared to that produced without BB. The specific surface area of VRB prepared with BB was 159% greater than that of the biochar without BB, and the CO2 adsorption capacity increased by 62.5%, reaching 34.75 mg/g. The pseudo-first-order and pseudo-second-order kinetic models were employed to analyze the CO2 adsorption by biochar. It was found that the pseudo-first-order kinetic model more accurately described the CO2 adsorption on biochar, indicating that physical adsorption predominantly governs the CO2 uptake by biochar.
