Microstructure and coloring mechanism of iron spots on bluish white porcelain from Jingdezhen of the Song Dynasty

Jingdezhen is famous for its bluish white (Qingbai) porcelains of the Song Dynasty, and those decorated with iron spots are distinctive among them. Herein, iron spots on a bluish white porcelain were investigated using a series of microscopic and spectroscopic characterizations. We found the decreasing iron content from more than 8 wt% to about 2 wt% during the glaze color transition from rusty to brown and finally into green, which built a connection on the coloring mechanism of iron-rich crystallized glaze and celadon glaze. We identified the rare ε-Fe₂O₃, a promising magnetic material, in both the dark brown crystals and the triangular crystals in the rusty area, which is its first discovery among bluish white porcelains. Based on these findings, we discussed the coloring mechanism of iron-spot decoration along with the physical form of the iron oxide crystals, indicating the partially reducing atmosphere during firing process.     

基于C#持久蠕变强度外推功能的实现

持久蠕变强度外推是预测材料在高温高压环境下工作寿命的有效方法。目前常用的外推方法有等温法和参数法。这两种方法都是通过在实验室中采用较短时间的试验，获取试验数据后，通过Excel或者MATLAB等数据处理软件进行数据的拟合处理和外推计算。这些数据归纳统计和数学建模的过程有时需要耗费试验人员的大量精力。介绍了持久蠕变强度外推的软件实现方法，该功能包含在持久蠕变试验设备配备的软件中，试验完成后，软件直接根据试验结果进行数据拟合和持久蠕变强度的外推计算，无需试验数据的统计和建模，大大提高了持久蠕变强度外推计算的效率。     

Environmental Enrichment Enhances Cav 2.1 Channel-Mediated Presynaptic Plasticity in Hypoxic–Ischemic Encephalopathy

Hypoxic–ischemic encephalopathy (HIE) is a devastating neonatal brain condition caused by lack of oxygen and limited blood flow. Environmental enrichment (EE) is a classic paradigm with a complex stimulation of physical, cognitive, and social components. EE can exert neuroplasticity and neuroprotective effects in immature brains. However, the exact mechanism of EE on the chronic condition of HIE remains unclear. HIE was induced by a permanent ligation of the right carotid artery, followed by an 8% O₂ hypoxic condition for 1 h. At 6 weeks of age, HIE mice were randomly assigned to either standard cages or EE cages. In the behavioral assessments, EE mice showed significantly improved motor performances in rotarod tests, ladder walking tests, and hanging wire tests, compared with HIE control mice. EE mice also significantly enhanced cognitive performances in Y-maze tests. Particularly, EE mice showed a significant increase in Ca_v 2.1 (P/Q type) and presynaptic proteins by molecular assessments, and a significant increase of Ca_v 2.1 in histological assessments of the cerebral cortex and hippocampus. These results indicate that EE can upregulate the expression of the Ca_v 2.1 channel and presynaptic proteins related to the synaptic vesicle cycle and neurotransmitter release, which may be responsible for motor and cognitive improvements in HIE.     

Co-doping effects of (Al,Ti, Mg) on the microstructure and electrical behavior of ZnO-based ceramics

Co-doped ZnO-based ceramics using Al, Ti, and Mg ions in different ratios were synthesized with the objective to investigate the doping effects on the crystalline features, microstructure and the electrical behavior. For Al and Ti doping, a coexistence of crystalline phases was shown with a major wurtzite ZnO structure and secondary spinel phases (ZnAl₂O₄, Zn₂TiO₄, or Zn_aTi_bAl_cO_d), while Mg doping did not alter significantly the structural features of the wurtzite ZnO phase. The electrical behavior induced by Al, Ti, and Mg co-doping in different ratios was investigated using Raman, electron paramagnetic resonance (EPR) and ²⁷Al and ⁶⁷Zn solid-state nuclear magnetic resonance (NMR). Al doping induces a high electrical conductivity compared to other doping elements. In particular, shallow donors from Zn_i-Al_Zn defect structures are inferred from the characteristic NMR signal at about 185 ppm; that is, quite far from the usual oxygen coordinated Al. The Knight shift effect emanating from a highly conducting Al-doped ZnO ceramics was considered as the origin of this observation. Oppositely, as Ti doping leads to the formation of secondary spinel phases, EPR analysis shows a high concentration of Ti³⁺ ions which limit the electrical conductivity. The correlation between the structural features at the local order, the involved defects and the electrical behavior as function of the doping process are discussed.     

Investigating volatile compounds’ contributions to the stale odour of green tea

This study aimed to characterise the volatiles that contribute to stale odour of green tea. Volatiles were extracted using headspace solid-phase microextraction (HS-SPME) and analysed using gas chromatography-mass spectrometry (GC-MS) and gas chromatography-olfactometry (GC-O). Results showed that a total of ninety-six volatiles were identified by GC-MS, in which forty-four volatiles were screened out based on Principal component analysis (PCA) and orthogonal projections to latent structures–discriminant analysis (OPLS-DA), and thirty-nine volatiles had a significant variation at the level of 0.05 by analysis of variance (anova ). From GC-O analysis, fifty-four aromatic volatiles with strong aroma intensity (aroma intensity above 2) were perceived. Further investigation revealed that fifteen volatiles, including 1-octen-3-ol, benzyl alcohol, benzaldehyde, safranal, β-cyclocitral, (E,E)-3,5-octadien-2-one, (Z,E)-3,5-octadien-2-one, dimethyl adipate, dihydroactinidiolide, β-ionone, α-ionone, geranyl acetone, phenylethyl alcohol, methyl decanoate and α-terpineol were responsible for stale odour, besides the former nine compounds were only found in stored tea.     

Inhibitory effect of cinnamon essential oils on selected cheese-contaminating fungi (Penicillium spp.) during the cheese-ripening process

The antifungal effects of essential oils (EOs) on cultures of the known cheese fungal contaminants Penicillium spp. were evaluated. Cinnamon leaf and bark EOs were the most effective among 8 EOs tested. The main components of both cinnamon EOs were eugenol, cinnamaldehyde, and linalool. Both inhibited growth of Penicillium spp. at a concentration of 10% v/v (2,000 ppm/mm²) on a lawn cell plate. When tested using 3 commercially available cheese starters, cinnamon EOs showed no effect against the FD-DVS ABT-5 cheese starter. However, growth of lactobacilli was inhibited in the presence of ≥10% (v/v) of leaf and bark EOs for the KAZU 1 starter, and ≥5% (v/v) for the FD-DVS FLORA-DANICA starter. A concentration of 4,000 ppm/mm² of cinnamon EOs completely inhibited growth of the Penicillium spp. that naturally contaminates the surface of Appenzeller cheese.     

Fracture Parameters for Natural Rubber Under Dynamic Loading

Abstract: An experimental study was conducted to evaluate the tear energy of unfilled and 25 phr carbon black‐filled natural rubber with varying loading rates. The variation of the tear energy with far‐field sample strain rate between 0.01 to 10 s^?1 was found to be different from tensile strip and pure shear specimens. Above a sample strain rate of 10 s^?1, the tear energy calculated from either specimen was comparable. The differences in the tear energy derived from the tensile strip and pure shear specimens were attributed to differences in the local crack tip stress state and strengthening of the material due to strain‐induced crystallisation. Both of these factors resulted in crack speeds 3–4 times higher in the pure shear specimen as compared to the tensile strip specimen. Finite element analysis (FEA) indicated that fracture would initiate at the crack tip either when the strain energy density approached the material toughness or when the maximum principal stress and strain approached the material tensile strength and fracture strain, respectively. It was concluded that these parameters would be better than the tear energy in predicting fracture of natural rubber under dynamic loading.     

柏林:城市街道的民主与活力

柏林在1990年德国统一之后重新成为民主德国的首都,东西柏林的历史隔阂和发展失衡的问题在新柏林城必须得到弥补,柏林墙倒塌后的裂痕地带在统一柏林的建设中成为联系东西柏林的纽带,政府区、中央火车站等一系列重要的城市功能区都规划建设在这一带。整个新柏林的规划建设都充满了联邦德国的反思,历史上希特勒独裁政治的伤疤、东西德的分裂促使重新统一后的德国对政治的透明性的重视,以坦诚的姿态表达对于"民主"的尊重。不仅是政治建筑本身,新柏林公共空间的设计和管理都反映出德国当局对于民主的态度——属于公众的城市空间在政治性空间中所占的地位是什么。街道是城市中最常见的开放空间,直接为市民的通行、休闲服务,在公众城市生活中占有重要分量。文章在柏林对几个较政治化的区域的街道空间进行了考察分析,探讨柏林如何保证城市街道的民主性,让街道生活充满活力。