Idealizing Tauc Plot for Accurate Bandgap Determination of Semiconductor with UV-Vis: A Case Study for Cubic Boron Arsenide

The Tauc plot method is widely used to determine the bandgap of semiconductors via UV-visible optical spectroscopy due to its simplicity and perceived accuracy. However, the actual Tauc plot often exhibits significant baseline absorption below the expected bandgap, leading to discrepancies in the calculated bandgap depending on whether the linear fit is extrapolated to zero or non-zero baseline. In this study, we show that both extrapolation methods can produce significant errors by simulating Tauc plots with varying levels of baseline absorption. To address this issue, we propose a new method that involves idealizing the absorption spectrum by removing its baseline before constructing the Tauc plot. Experimental verification of this method using a gallium phosphide (GaP) wafer with intentionally introduced baseline absorptions shows promising results. Furthermore, we apply this new method to cubic boron arsenide (c-BAs) and resolve discrepancies in c-BAs bandgap values reported by different groups, obtaining a converging bandgap of 1.835 eV based on both previous and new transmission spectra. The method is applicable to both indirect and direct bandgap semiconductors, regardless of whether the absorption spectrum is measured via transmission or diffuse reflectance, will become essential to obtain accurate values of their bandgaps

Functional Properties of Glutinous Rice Flour by Dry-Heat Treatment.

Glutinous rice flour (GRF) and glutinous rice starch (GRS) were modified by dry-heat treatment and their rheological, thermal properties and freeze-thaw stability were evaluated. Compared with the native GRF and GRS, the water-holding ability of modified GRF and GRS were enhanced. Both the onset and peak temperatures of the modified samples increased while the endothermic enthalpy change decreased significantly (p < 0.05). Meanwhile, dry heating remarkably increased the apparent viscosities of both GRF and GRS. Importantly, compared with GRS samples, the storage modulus (G') and loss modulus (G") values of modified GRF increased more greatly and the tanδ values decreased more remarkably, indicating that the dry-heat treatment showed more impact on the GRF and a higher viscoelasticity compared with GRS. Our results suggest the dry-heat treatment of GRF is a more effective method than that of GRS, which omits the complex and tedious process for purifying GRS, and thereby has more practical applications in the food industry

The freeze-thaw stability images of the GRS (A) and GRF (B) before and after dry heating.

<p>GRS2 h, 4 h: the glutinous rice starch (GRS) pastes after dry-heat treatment at 130°C for 2, 4 h; GRF2 h, 4 h: the glutinous rice flour (GRF) pastes after dry-heat treatment at 130°C for 2, 4 h. Data represents results from at least three independent experiments and are expressed as mean values ± standard deviations. Different lowercase and capital letters in the same images are significantly different (<i>p</i> < 0.05).</p

Relationship between shearing stress and shearing rate of GRS (A) and GRF (B) before and after dry heating.

<p>GRS2 h, 4 h: the glutinous rice starch (GRS) pastes after dry-heat treatment at 130°C for 2, 4 h; GRF2 h, 4 h: the glutinous rice flour (GRF) pastes after dry-heat treatment at 130°C for 2, 4 h. The data points represent the mean values of three samples and error bars show the standard deviation.</p

Cirsium yezoense Makino

原著和名: サハアザミ科名: キク科 = Compositae採集地: 岩手県 下閉伊郡 岩泉町 安家 (陸中 下閉伊郡 岩泉町 安家)採集日: 1966/9/23採集者: 萩庭丈壽整理番号: JH004631国立科学博物館整理番号: TNS-VS-95463

Loss tangent (tanδ = G"/G') as a function of angular frequency for the GRS (A) and GRF (B) before and after dry heating.

<p>GRS2 h, 4 h: the glutinous rice starch (GRS) pastes after dry-heat treatment at 130°C for 2, 4 h; GRF2 h, 4 h: the glutinous rice flour (GRF) pastes after dry-heat treatment at 130°C for 2, 4 h. The data points represent the mean values of three samples and error bars show the standard deviation.</p

Storage modulus (G') and loss modulus (G") as a function of angular frequency for the GRS (A and B) and GRF (C and D) before and after dry heating.

<p>GRS2 h, 4 h: the glutinous rice starch (GRS) pastes after dry-heat treatment at 130°C for 2, 4 h; GRF2 h, 4 h: the glutinous rice flour (GRF) pastes after dry-heat treatment at 130°C for 2, 4 h. The data points represent the mean values of three samples and error bars show the standard deviation.</p

Chemical Composition of glutinous rice starch (GRS) and glutinous rice flour (GRF).

<p>Chemical Composition of glutinous rice starch (GRS) and glutinous rice flour (GRF).</p

Relationship between apparent viscosity and shearing rate of the GRS (A) and GRF (B) before and after dry heating.

<p>GRS2 h, 4 h: the glutinous rice starch (GRS) pastes after dry-heat treatment at 130°C for 2, 4 h; GRF2 h, 4 h: the glutinous rice flour (GRF) pastes after dry-heat treatment at 130°C for 2, 4 h. The data points represent the mean values of three samples and error bars show the standard deviation.</p

N 6-methyladenosine modification-mediated mRNA metabolism is essential for human pancreatic lineage specification and islet organogenesis

Ma et al. profile the dynamic landscape of m6A during pancreatic differentiation, and identify ALKBH5 as an essential m6A regulator supporting pancreatic differentiation, indicating a role for m6A-mediated mRNA metabolism in cell-fate specification