A Spectroscopic Study on Singlet Oxygen Production from Different Reaction Paths Using Solid Inorganic Peroxides as Starting Materials

Li, Qingwei,Chen, Fang,Zhao, Weili,Xu, Mingxiu,Fang, Benjie,Zhang, Yuelong,Duo, Liping,Jin, Yuqi,Sang, Fengting Korean Chemical Society 2007 Bulletin of the Korean Chemical Society Vol.28 No.10

Using solid inorganic peroxides (including Li2O2, Na2O2, SrO2 and BaO2) as starting materials, three reaction paths for singlet oxygen (1O2) production were developed and studied. Their 1O2 emission spectra in the near- IR region and visible region from these reaction paths were simultaneously recorded by a near-IR sensitive Optical Multichannel Analyzer and a visible sensitive Optical Spectrum Analyzer, respectively. The comparison of their 1O2 emission spectra indicated that: (1) in term of the efficiency for 1O2 production, the gasliquid- solid reaction path (in which Cl2 or HCl and H2O reacted with the solid inorganic peroxides suspension in CCl4) was prior to the gas-solid reaction path (in which Cl2 or HCl reacted with the solid inorganic peroxides suspension in CCl4), but was inferior to the gas-liquid reaction path (in which Cl2 or HCl reacted with the solid inorganic peroxides solution in H2O or D2O); (2) the alkali metal peroxides (such as Li2O2 and Na2O2) was prior to the alkaline earth metal peroxides (such as SrO2 and BaO2) as the solid reactants, and Cl2 was favorable than HCl as the gas reactant in efficiency for 1O2 production in these reaction paths.

A Spectroscopic Study on Singlet Oxygen Production from Different Reaction Paths Using Solid Inorganic Peroxides as Starting Materials

Qingwei Li*,Fang Chen,Weili Zhao,Mingxiu Xu,Benjie Fang,Yuelong Zhang,Liping Duo,Yuqi Jin,Fengting Sang 대한화학회 2007 Bulletin of the Korean Chemical Society Vol.28 No.10

Using solid inorganic peroxides (including Li2O2, Na2O2, SrO2 and BaO2) as starting materials, three reaction paths for singlet oxygen (1O2) production were developed and studied. Their 1O2 emission spectra in the near-IR region and visible region from these reaction paths were simultaneously recorded by a near-IR sensitive Optical Multichannel Analyzer and a visible sensitive Optical Spectrum Analyzer, respectively. The comparison of their 1O2 emission spectra indicated that: (1) in term of the efficiency for 1O2 production, the gas-liquid-solid reaction path (in which Cl2 or HCl and H2O reacted with the solid inorganic peroxides suspension in CCl4) was prior to the gas-solid reaction path (in which Cl2 or HCl reacted with the solid inorganic peroxides suspension in CCl4), but was inferior to the gas-liquid reaction path (in which Cl2 or HCl reacted with the solid inorganic peroxides solution in H2O or D2O); (2) the alkali metal peroxides (such as Li2O2 and Na2O2) was prior to the alkaline earth metal peroxides (such as SrO2 and BaO2) as the solid reactants, and Cl2 was favorable than HCl as the gas reactant in efficiency for 1O2 production in these reaction paths.

Scalable joint segmentation and registration framework for infant brain images

Dong, Pei,Wang, Li,Lin, Weili,Shen, Dinggang,Wu, Guorong Elsevier 2017 Neurocomputing Vol.229 No.-

<P><B>Abstract</B></P> <P>The first year of life is the most dynamic and perhaps the most critical phase of postnatal brain development. The ability to accurately measure structure changes is critical in early brain development study, which highly relies on the performances of image segmentation and registration techniques. However, either infant image segmentation or registration, if deployed independently, encounters much more challenges than segmentation/registration of adult brains due to dynamic appearance change with rapid brain development. In fact, image segmentation and registration of infant images can assists each other to overcome the above challenges by using the growth trajectories (i.e., temporal correspondences) learned from a large set of training subjects with complete longitudinal data. Specifically, a one-year-old image with ground-truth tissue segmentation can be first set as the reference domain. Then, to register the infant image of a new subject at earlier age, we can estimate its tissue probability maps, i.e., with sparse patch-based multi-atlas label fusion technique, where only the training images at the respective age are considered as atlases since they have similar image appearance. Next, these probability maps can be fused as a good initialization to guide the level set segmentation. Thus, image registration between the new infant image and the reference image is free of difficulty of appearance changes, by establishing correspondences upon the reasonably segmented images. Importantly, the segmentation of new infant image can be further enhanced by propagating the much more reliable label fusion heuristics at the reference domain to the corresponding location of the new infant image via the learned growth trajectories, which brings image segmentation and registration to assist each other. It is worth noting that our joint segmentation and registration framework is also flexible to handle the registration of any two infant images even with significant age gap in the first year of life, by linking their joint segmentation and registration through the reference domain. Thus, our proposed joint segmentation and registration method is scalable to various registration tasks in early brain development studies. Promising segmentation and registration results have been achieved for infant brain MR images aged from 2-week-old to 1-year-old, indicating the applicability of our method in early brain development study.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We developed an efficient approach to deal with the tissue segmentation and registration for the infant brain MR images. </LI> <LI> Our proposed framework is scalable to various registration tasks in early brain development studies. </LI> <LI> Promising results have been achieved for infant brain MR images aged from 2-week-old to 1-year-old. </LI> <LI> The proposed technique can be very useful for many ongoing early brain development studies. </LI> </UL> </P>

Mapping Longitudinal Development of Local Cortical Gyrification in Infants from Birth to 2 Years of Age

Li, Gang,Wang, Li,Shi, Feng,Lyall, Amanda E.,Lin, Weili,Gilmore, John H.,Shen, Dinggang Society for Neuroscience 2014 The Journal of neuroscience Vol.34 No.12

<P>Human cortical folding is believed to correlate with cognitive functions. This likely correlation may have something to do with why abnormalities of cortical folding have been found in many neurodevelopmental disorders. However, little is known about how cortical gyrification, the cortical folding process, develops in the first 2 years of life, a period of dynamic and regionally heterogeneous cortex growth. In this article, we show how we developed a novel infant-specific method for mapping longitudinal development of local cortical gyrification in infants. By using this method, via 219 longitudinal 3T magnetic resonance imaging scans from 73 healthy infants, we systemically and quantitatively characterized for the first time the longitudinal cortical global gyrification index (GI) and local GI (LGI) development in the first 2 years of life. We found that the cortical GI had age-related and marked development, with 16.1% increase in the first year and 6.6% increase in the second year. We also found marked and regionally heterogeneous cortical LGI development in the first 2 years of life, with the high-growth regions located in the association cortex, whereas the low-growth regions located in sensorimotor, auditory, and visual cortices. Meanwhile, we also showed that LGI growth in most cortical regions was positively correlated with the brain volume growth, which is particularly significant in the prefrontal cortex in the first year. In addition, we observed gender differences in both cortical GIs and LGIs in the first 2 years, with the males having larger GIs than females at 2 years of age. This study provides valuable information on normal cortical folding development in infancy and early childhood.</P>

Spatial Patterns, Longitudinal Development, and Hemispheric Asymmetries of Cortical Thickness in Infants from Birth to 2 Years of Age

Li, Gang,Lin, Weili,Gilmore, John H.,Shen, Dinggang Society for Neuroscience 2015 The Journal of neuroscience Vol.35 No.24

<P>Cortical thickness (CT) is related to normal development and neurodevelopmental disorders. It remains largely unclear how the characteristic patterns of CT evolve in the first 2 years. In this paper, we systematically characterized for the first time the detailed vertex-wise patterns of spatial distribution, longitudinal development, and hemispheric asymmetries of CT at 0, 1, and 2 years of age, via surface-based analysis of 219 longitudinal magnetic resonance images from 73 infants. Despite the dynamic increase of CT in the first year and the little change of CT in the second year, we found that the overall spatial distribution of thin and thick cortices was largely present at birth, and evolved only modestly during the first 2 years. Specifically, the precentral gyrus, postcentral gyrus, occipital cortex, and superior parietal region had thin cortices, whereas the prefrontal, lateral temporal, insula, and inferior parietal regions had thick cortices. We revealed that in the first year thin cortices exhibited low growth rates of CT, whereas thick cortices exhibited high growth rates. We also found that gyri were thicker than sulci, and that the anterior bank of the central sulcus was thicker than the posterior bank. Moreover, we showed rightward hemispheric asymmetries of CT in the lateral temporal and posterior insula regions at birth, which shrank gradually in the first 2 years, and also leftward asymmetries in the medial prefrontal, paracentral, and anterior cingulate cortices, which expanded substantially during this period. This study provides the first comprehensive picture of early patterns and evolution of CT during infancy.</P>

Efficient quantum secure communication scheme with one-time pad

Li, Yuan,Zeng, Guihua,Yao, Weili,Lee, Moonho Springer-Verlag 2009 Optical review Vol.16 No.3

Experimental Study on Synchronous Shifting for AMT without Synchronizer Based on Three-phase Induction Motor

Yunxia LI,Zengcai WANG,Weili PENG,Zhou ZHENG 보안공학연구지원센터 2016 International Journal of Smart Home Vol.10 No.2

In order to reduce shifting jerks, synchronous shift is needed on transmission with gear ratios. How to achieve synchronous shift has been the difficulty of AMT (Automated Mechanical Transmission) without synchronizer, which is the main emphasis of shift schedule. In this paper, the experimental study on synchronous up-shifting and down-shifting is given by test-bed which consisted of three-phase induction motor and heavy-duty AMT without synchronizer. Based on shift model, the synchronous speed difference is put forward for the synchronous shift strategy. The synchronizing control strategy of up-shifting is proposed on the basis of the braking characteristics of TB (transmission brake). The synchronizing control strategy of down-shifting is given according to the characteristics of the three-phase induction motor. Under the conditions of various synchronous speed differences, the up-shifting experiments and down-shifting experiments are achieved. By comparisons, the best value of synchronous speed difference is discussed in terms of gear-position and working conditions. The results of shifting experiments show that the synchronous shifting strategies for AMT without synchronizer based on three-phase induction can decrease shifting jerks and improve shift qualities.

A Novel Video Stitching Method for Multi-Camera Surveillance Systems

( Xiaoqing Yin ),( Weili Li ),( Bin Wang ),( Yu Liu ),( Maojun Zhang ) 한국인터넷정보학회 2014 KSII Transactions on Internet and Information Syst Vol.8 No.10

This paper proposes a novel video stitching method that improves real-time performance and visual quality of a multi-camera video surveillance system. A two-stage seam searching algorithm based on enhanced dynamic programming is proposed. It can obtain satisfactory result and achieve better real-time performance than traditional seam-searching methods. The experiments show that the computing time is reduced by 66.4% using the proposed algorithm compared with enhanced dynamic programming, while the seam-searching accuracy is maintained. A real-time local update scheme reduces the deformation effect caused by moving objects passing through the seam, and a seam-based local color transfer model is constructed and applied to achieve smooth transition in the overlapped area, and overcome the traditional pixel blending methods. The effectiveness of the proposed method is proved in the experiements.

Structure of a permanent magnet motor used for electric vehicles to suppress the eddy current effect

Meiwei Zhang,Weili Li,Wanlu Xie,Liangliang Zhang 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.9

A demagnetization fault in the permanent magnet (PM) may occur when the temperature exceeds the limit temperature of the PM material due to the limited heat dissipation of the rotor in PM motors in the driving system of electric vehicles. In addition, PM thermal stress arises as a result of the unbalanced axial temperature distribution of the motor. When the thermal stress exceeds the yield strength of PM, micro-deformation of the PM structure happens and affects the performance and structural reliability of the motor. In this study, the rotor structure of an 18 kW PM motor is improved, and an eddy current ring structure of stainless steel is proposed. First, the effects of eddy current rings with axial lengths of 2, 5, and 10 mm on the eddy current losses of PM are compared. Second, a three-dimensional, steady-state temperature model of the motor is established to analyze the effects of the eddy current rings with different axial lengths on rotor temperature when the motor is running at different speeds. Results show that the eddy current ring structure with 2 mm axial length has the best effect on reducing rotor temperature. Lastly, the simulation results are verified using the test results of the 18 kW PM motor.

Research on the Calculation of Rotor’s Convective Heat Transfer Coefficient of High-Speed Drive Motor for EVs Based on Multiple Scenarios

Wu Zhigang,Li Weili,Tang Haoyue,Luo Shifan,Zhang Liangliang 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.6

In order to adapt the development demand of electric vehicle (EV) drive motor with high power density, high-speed motor is an inevitable trend. There have been numerous studies on the optimisation of cooling structures and losses in high-speed motor, but little has been said about the mechanism of heat transfer problems. Especially in the context of diverse driving scenarios and high-speed drive for EVs, it is crucial to study the differences in heat transfer mechanisms between high-speed motors and normal-speed motors. The research work is based on a principle prototype with a maximum speed of 50 kW-30,000 rpm. A dynamic calculation method is proposed for the rotor’s convective heat transfer coefficient (CHTC) over a wide speed range and multiple scenarios. This method has the advantages of simplicity and high efficiency in calculating the CHTC of rotor, and avoids the complex preprocessing and difficult convergence problems of the fluid–solid coupling calculation. Finally, the accuracy of the calculation results is verified by the temperature rise test of the high-speed motor.