Mo掺杂Mn4Si7的光电性质的第一性原理计算

采用基于密度泛函理论(DFT)的第一性原理计算方法,计算了Mn4Si7及Mo掺杂Mn4Si7的电子结构和光学性质.计算结果表明Mn4 Si7的禁带宽度Eg=0.804 eV,Mo掺杂Mn4Si7的禁带宽度Eg=0.636 eV.掺杂使得Mn4 Si7费米面附近的电子结构发生改变,导带底由Γ点转移为Y点向低能方向下偏移,价带顶向高能方向上偏移,带隙变窄.计算还表明Mo掺杂Mn4Si7使介电函数、折射率、吸收系数及光电导率等光学性质增加.     

An equivalent nonlinearization method for analysing response of nonlinear systems to random excitations

I.IntroductionInthelasttwodecades,theresponseofstochasticallyexcitednonlinearsystemshavebeenresearcheddeeplyandwidely.Manyexactandapproximatemethodsofpredictingtheresponseofnonlinearsystemstorandomexcitationshavebeenprop0sedl']'l21.Becauseofv4riousreasons…     

椭圆截面曲线管道内二次流动的Galerkin解

推导了任意空间曲线直角坐标系内的张量流体力学方程．采用Galerkin方法和计算机符号运算技术求解了椭圆截面螺旋管道（电括弯管、扭管）内的二次流动．计算结果表明了Galerkin方法的适用和有效性，克服了振动法的小参数局限．对所得结果的分析揭示了椭圆截面螺旋管道内流动的特性，给出了k,r和Re较大情况的研究结论．     

低温溶胶凝胶法制备TiO2薄膜减摩性能的研究

采用溶胶-凝胶法并结合水热后处理技术在金属铜表面制备了TiO_2薄膜,利用扫描电子显微镜、X射线衍射对薄膜的表面形貌、晶型进行了表征,通过极化曲线研究了TiO_2薄膜在3.5%NaCl水溶液中的耐蚀性能,并考察了TiO_2薄膜的摩擦磨损性能.结果表明:170℃下水热处理后得到的TiO_2薄膜与480℃直接焙烧处理制备的TiO_2薄膜的表面形貌和晶型存在着明显差异,前者具有较低的摩擦系数和更长的耐磨寿命,同时在3.5%Na Cl溶液中的耐蚀性能也明显优于后者.     

仿生非光滑表面铸铁材料的常温摩擦磨损性能

模仿动物体表形态,在试样表面通过激光雕刻出有规则分布的凹坑以及条纹等非光滑单元体,研究了具有非光滑表面材料的摩擦磨损性能.结果表明:非光滑表面材料的耐磨性较光滑表面提高1倍以上,摩擦系数提高66%以上;当非光滑表面的单元体硬度越高、直径越大和间距越小时,其耐磨性能越好,摩擦系数越大.这是由于激光加工的单元体相当于在母体上增加了许多强化质点,比母体具有较高的硬度和致密性,能够提高抗磨性,增加表面粗糙度,所以其耐磨性提高,摩擦系数增大.     

运动状态下液体轴对称抛撒首次破碎的实验研究

在实验室条件下利用组合式激波管设备,对运动状态下液体轴对称抛撒进行了实验研究。通过纹影装置获得其所形成雾化场的外形轮廓照片,测量获得了液核发生首次破碎的位置与对称轴之间的距离。通过对抛撒过程中R-T不稳定性与K-H不稳定性的分析认为,轴向气流作用下液体轴对称抛撒的首次破碎点与对称轴的距离主要由轴向气流的速度、轴向气流的密度、液体轴对称抛撒的出口速度、抛撒液体的表面张力系数、环形喷口的宽度等参数所决定。在此基础上,利用相似性理论和无量纲分析,获得了运动状态下液体轴对称抛撒首次破碎点与对称轴之间的距离与相关参数的无量纲关系式。     

The reactions of ground state Cu+ and Fe+ with the 20 common amino acids

A systematic investigation of the gas-phase reactions of Cu⁺ and Fe⁺ with the 20 common amino acids is reported. Metal ions are formed by laser ablation of a metal target and are trapped in the analyzer cell of a Fourier transform mass spectrometer. By using quadrupolar excitation to axialize the metal ions, tens of thousands of thermalizing collisions occur prior to their reactions with laser-desorbed amino acid neutral molecules. Amino acids with nonpolar side chains are found to be more reactive toward Cu⁺ and Fe⁺ than amino acids with polar side chain. Many of the nonpolar amino acids are found to undergo dissociative metal attachment with a neutral loss of 46 u. A ¹³C-labeling experiment shows that the carboxyl group is lost during dissociative metal attachment to amino acids. Together these results suggest that these metal ions interact primarily with the carboxyl functional group in these molecules.     

LC–MS3 Strategy for Quantification of Carbamazepine in Human Plasma and Its Application in Therapeutic Drug Monitoring

This study developed a detection method based on the strategy of HPLC/MS³ and verified its suitability by quantifying carbamazepine in human plasma. The high-performance liquid chromatography–tandem mass spectrometry (HPLC/MS³) system was performed using a Shimadzu UFLC XR liquid chromatography and a SCIEX QTRAP^® 5500 linear ion trap triple quadrupole mass spectrometer. The specific operation was as follows: the sample protein was firstly precipitated using methanol, then carbamazepine and carbamazepine-D₂N¹⁵ were separated on an ACQUITY UPLC HSS T3 column using the gradient elution with solvent A (0.1% formic acid) and solvent B (0.1% formic acid in acetonitrile) at a flow rate of 0.25 mL/min. Each sample was run for 7 min. This method was validated for various parameters including accuracy, precision, selectivity, linearity, LLOQ, etc. Only 5 μL of sample plasma could obtain the result of LLOD 0.5 µg/mL. The intra-day and inter-day precision was <8.23%, and accuracy was between −1.74% and 2.92%. This method was successfully used for monitoring the blood concentration of epilepsy patients after carbamazepine treatment.     

Cytosolic escape of mitochondrial DNA triggers cGAS-STING-NLRP3 axis-dependent nucleus pulposus cell pyroptosis

Low back pain (LBP) is a major musculoskeletal disorder and the socioeconomic problem with a high prevalence that mainly involves intervertebral disc (IVD) degeneration, characterized by progressive nucleus pulposus (NP) cell death and the development of an inflammatory microenvironment in NP tissue. Excessively accumulated cytosolic DNA acts as a damage-associated molecular pattern (DAMP) that is monitored by the cGAS-STING axis to trigger the immune response in many degenerative diseases. NLRP3 inflammasome-dependent pyroptosis is a type of inflammatory programmed death that promotes a chronic inflammatory response and tissue degeneration. However, the relationship between the cGAS-STING axis and NLRP3 inflammasome-induced pyroptosis in the pathogenesis of IVD degeneration remains unclear. Here, we used magnetic resonance imaging (MRI) and histopathology to demonstrate that cGAS, STING, and NLRP3 are associated with the degree of IVD degeneration. Oxidative stress induced cGAS-STING axis activation and NLRP3 inflammasome-mediated pyroptosis in a STING-dependent manner in human NP cells. Interestingly, the canonical morphological and functional characteristics of mitochondrial permeability transition pore (mPTP) opening with the cytosolic escape of mitochondrial DNA (mtDNA) were observed in human NP cells under oxidative stress. Furthermore, the administration of a specific pharmacological inhibitor of mPTP and self-mtDNA cytosolic leakage effectively reduced NLRP3 inflammasome-mediated pyroptotic NP cell death and microenvironmental inflammation in vitro and degenerative progression in a rat disc needle puncture model. Collectively, these data highlight the critical roles of the cGAS-STING-NLRP3 axis and pyroptosis in the progression of IVD degeneration and provide promising therapeutic approaches for discogenic LBP.Subject terms: Cell death, Diseases     

Zinc-Guided 3D Graphene for Thermally Chargeable Supercapacitors to Harvest Low-Grade Heat

Low-grade heat energy recycling is the key technology of waste-heat utilization, which needs to be improved. Here, we use a zinc-assisted solid-state pyrolysis route to prepare zinc-guided 3D graphene (ZnG), a 3D porous graphene with the interconnected structure. The obtained ZnG, with a high specific surface area of 1817 m²·g⁻¹ and abundant micropores and mesopores, gives a specific capacitance of 139 F·g⁻¹ in a neutral electrolyte when used as electrode material for supercapacitors. At a high current density of 8 A·g⁻¹, the capacitance retention is 93% after 10,000 cycles. When ZnG is used for thermally chargeable supercapacitors, the thermoelectric conversion of the low-grade heat energy is successfully realized. This work thus provides a demonstration for low-grade heat energy conversion.