The Υ(1S)\Upsilon(1S) leptonic decay using the principle of maximum conformality

In the paper, we study the $\Upsilon(1S)$ leptonic decay width $\Gamma(\Upsilon(1S)\to \ell^+\ell^-)$ by using the principle of maximum conformality (PMC) scale-setting approach. The PMC adopts the renormalization group equation to set the correct momentum flow of the process, whose value is independent to the choice of the renormalization scale and its prediction thus avoids the conventional renormalization scale ambiguities. Using the known next-to-next-to-next-to-leading order perturbative series together with the PMC single scale-setting approach, we do obtain a renormalization scale independent decay width, $\Gamma_{\Upsilon(1S) \to e^+ e^-} = 1.262^{+0.195}_{-0.175}$ keV, where the error is squared average of those from $\alpha_s(M_{Z})=0.1181\pm0.0011$, $m_b=4.93\pm0.03$ GeV and the choices of factorization scales within $\pm 10\%$ of their central values. To compare with the result under conventional scale-setting approach, this decay width agrees with the experimental value within errors, indicating the importance of a proper scale-setting approach.Comment: 6 pages, 4 figure

An Analysis of Background Interference on Fire Debris

AbstractIn this study, the controlled burn experiments of carpets with and without gasoline in this study and commonly encountered substrates produced complex chromatograms producing peaks that were identified by mass spectrometry and comparison with reference standards and each other. The result shown that many of the compounds frequently encountered as a result of either combustion products or pyrolysis products of carpets detected in fresh gasoline as well. These compounds as background interferences that detect weather the gasoline exist in carpet combustion products or not

The Analysis of UV on No Traces Combustion-supporting in Fire Residue

AbstractIn this paper, the ethyl nitrite which ethanol and sodium nitrite's reaction product has the UV absorption peaks in 300nm∼ 400nm to qualitative identification for ethanol. The methanol has the similar absorption peaks in the same range, but these peaks have blue shift or red shift as the steric effects. Quantitative analysis of residual ethanol by the establishment of standard curves and recovery tests and other data analysis. Thus complete the qualitative and quantitative identification of ethanol

Recurrent Chunking Mechanisms for Long-Text Machine Reading Comprehension

In this paper, we study machine reading comprehension (MRC) on long texts, where a model takes as inputs a lengthy document and a question and then extracts a text span from the document as an answer. State-of-the-art models tend to use a pretrained transformer model (e.g., BERT) to encode the joint contextual information of document and question. However, these transformer-based models can only take a fixed-length (e.g., 512) text as its input. To deal with even longer text inputs, previous approaches usually chunk them into equally-spaced segments and predict answers based on each segment independently without considering the information from other segments. As a result, they may form segments that fail to cover the correct answer span or retain insufficient contexts around it, which significantly degrades the performance. Moreover, they are less capable of answering questions that need cross-segment information. We propose to let a model learn to chunk in a more flexible way via reinforcement learning: a model can decide the next segment that it wants to process in either direction. We also employ recurrent mechanisms to enable information to flow across segments. Experiments on three MRC datasets -- CoQA, QuAC, and TriviaQA -- demonstrate the effectiveness of our proposed recurrent chunking mechanisms: we can obtain segments that are more likely to contain complete answers and at the same time provide sufficient contexts around the ground truth answers for better predictions