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A hybrid model for the charging process of the amorphous SiO_2 film in radio frequency microelectromechanical system capacitive switches

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Chinese Physics B 2011年第3期20卷 426-432页

作者：王立峰黄庆安唐洁影廖小平 key laboratory of MEMS of the Ministry of education Southeast University

Charging is one of the most important reliability issues in radio frequency microelectro- mechanical systems （RF MEMS） capacitive switches since it makes the actuation voltage unstable. This paper proposes a hybrid model to describe the transient dielectric charging and discharging process in the defect-rich amorphous SiO2 RF MEMS capacitive switches and verifies experimentally. The hybrid model contains two parts according to two different charging mechanisms of the amorphous SiO2, which are the polarisation and charge injection. The models for polarisation and for charge injection are established, respectively. Analysis and experimental results show that polarisation is always effective, while the charge injection has a threshold electric field to the amorphous SiO2 film. Under different control voltage conditions, the hybrid model can accurately describe the experimental data.

关键词： modeling polarisation charge injection amorphous SiO2

A Robust on-Wafer Large Signal Transistor Characterization Method at mm-Wave Frequency

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Chinese Journal of Electronics 2019年第4期28卷 871-877页

作者： SU Jiangtao CAI Jialin ZHENG Xing SUN Lingling key laboratory of RF Circuits and Systems Ministry of Education

Accurate on-wafer large signal characterization of RF transistor is crucial for the optimum design of wireless communication circuits. We report a novel and systematic measurement method for the accurate acquisition of input and output power of on-wafer transistors up to 40 GHz. This method employs external couplers to extract the travelling waves, combined with a novel large signal calibration algorithm to calculate the power at on-wafer probe tip. The accuracy of this method was bench marked versus conventional approaches in a real measurement bench, and further been verified by characterizing the large signal response of a 0.25μm GaN HEMT device. It is concluded that the measurement uncertainty has been greatly decreased with this new method, especially at mm-wave frequencies.

关键词： Calibration Nonlinear measurement RF power amplifier mm-wave band On-wafer test

Theoretical study of electromechanical property in a p-type silicon nanoplate for mechanical sensors

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Chinese Physics B 2008年第11期17卷 4292-4299页

作者：张加宏黄庆安于虹雷双瑛 key laboratory of MEMS of Ministry of education Southeast University

Electromechanical property of a p-type single-crystal silicon nanoplate is modelled by a microscopic approach where the hole quantization effect and the spin-orbit coupling effect are taken into account. The visible anisotropic subband structures are calculated by solving self-consistently the stress-dependent 6×6 k.p Schrodinger equation with the Poisson equation. The strong mixing among heavy, light, and split-off holes is quantitatively assessed. The influences of the thickness and the temperature on the piezoresistive coefficient are quantitatively investigated by using the hole concentrations and the effective masses from the complex dispersion structure of the valence band with and without stresses. Our results show that the stress determines the extent to which the band is mixed. The hole quantization effect increases as the thickness decreases, and therefore the valence band is strongly reshaped, resulting in the size-dependent piezoresistivity of the silicon nanoplate. The piezoresistive coefficient increases almost 4 times as the thickness reduces from the bulk to 3 nm, exhibiting a promising application in mechanical sensors.

关键词： silicon nanoplate piezoresistive band structure band mixing

A novel method for generating a rectangular convex corner compensation structure in an anisotropic etching process

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Journal of Semiconductors 2009年第7期30卷 33-38页

作者：张涵李伟华 key laboratory of MEMS of the Ministry of education Southeast University

Detailed characteristics of three classical rectangular convex corner compensation structures on（100） silicon substrates have been investigated, and their common design steps are *** combining the basic method of a silicon wet anisotropic etching process, a general method of generating compensation structures for a rectangular convex corner is put *** calls for the following two steps：define the topological field and fit some borderlines together into practical compensation *** rules, which must be obeyed during this process, are *** introducing this method, some novel compensation patterns for rectangular convex corner structures are created on both（100） and（110） substrates, and finally simulation results are given to prove this new method＇s validity and applicability.

关键词： rectangular convex corner compensation anisotropic etching general methodology

Organochlorine pesticide and heavy metal residues in some edible biota collected from Quanzhou Bay and Xinghua Bay,Southeast China

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Journal of Environmental Sciences 2010年第2期22卷 314-320页

作者： Mangala Yatawara Odhiambo Joshua Owago Julia E Burnet key laboratory of Biogeology and Environmental Geology of Ministry of education

In order to assess the contamination of edible marine organisms in Quanzhou and Xinghua Bays, Fujian Province, China, concentrations of organochlorine pesticides （hexachlorocyclohexane isomers or HCHs and dichlorodiphenyltrichloroethane isomers/derivatives or DDTs） and heavy metals （Cu, Pb, Zn, As, Cr, Cd, Ni and Hg） in 13 species collected from different sites in the hays were analyzed by GC-ECD and ICP-MS. The concentration of the sum of DDTs exceeded that the sum of HCHs in the samples. Most of the organisms showed higher levels of DDTs than the first level criterion （10 ng/g） for marine biological quality in China （GB 18421-2001） but conformed to the first level criterion （20 ng/g） for HCHs. The estimated mean daily uptake of pesticides was below the level for minimal risk to the consumers. The levels of Cd, As and Pb in most organisms from both bays were markedly elevated and above the recommended legal limits for human consumption. Our results showed the need for routine monitoring of marine species contamination to ensure public and environmental health.

关键词： organochlorine pesticides residue levels technical HCH heavy metals Fujian Province

Detecting magnetic field direction by a micro beam operating in different vibration modes

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Chinese Physics B 2011年第9期20卷 323-328页

作者：陈洁秦明黄庆安 key laboratory of MEMS of Ministry of education Southeast University

A new method to detect the magnetic field direction by using a silicon structure is presented in this paper. The structure includes a micro beam and an in-plane coil electrode. When the electrode under a magnetic field is applied with an alternating current, the micro beam is actuated under the effect of the Lorentz forces. Magnetic fields of different directions cause different vibration profiles. The direction of the magnetic field is obtained by measuring the vibration amplitudes of the micro beam, which is driven to work at first- and second-order resonant modes. A micro structure has been fabricated using the bulk microma^hined silicon process. A laser Doppler vibrometer system is implemented to measure the vibration amplitudes. The experimental results show that the amplitude of the structure, which depends on the different modes, is a sine or cosine function of the angle of the magnetic field. It agrees well with the simulation result. Currently a resolution of 10~ for the magnetic field direction measurement can be obtained using the detecting principle.

关键词： beam micro-electro-mechanical systems Lorentz force resonance

Experimental investigation of the factors affecting accuracy and resolution of the pore structure of cement-based materials by thermoporometry

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2013年第10期14卷 720-730页

作者： Zheng-wu JIANG Wen-ting LI Zi-long DENG Zhi-guo YAN key laboratory of Advanced Civil Engineering Materials of Ministry of education Tongji University key laboratory of Geotechnical and Underground Engineering of Ministry of education Tongji University

Thermoporometry(TPM) is a calorimetric-based technique for characterizing pore structure according to the freezing and melting point depression of liquid confined in pores which attributes to a varying phase-transition free energy by interface *** has demonstrated an emerging success in applications for determining the mesopores of cement-based materials in recent *** improve its resolution and accuracy,this paper discussed these factors which show a great influence on the baseline heat flow and the derived pore structure using two molecular sieves with discontinuous size for calibration,referring to the sample handling,the mass of sample and the varying *** pore size distributions of ordinary and high-strength concrete by TPM were favorably compared to the results taken by nitrogen adsorption/desorption(NAD) and mercury intrusion porosimetry(MIP).The results illustrated that both the accuracy and resolution improve with the decreasing cooling/heating rate until 1 °C/min;however,if the rate is too slow,it can lead to an unstable *** mass of the sample tested has much less an effect on the accuracy when it increases to more than 30 *** is demonstrated to be more accurate to characterize the mesopores with the size bigger than 4 nm as compared to NAD and MIP.

关键词： Thermoporometry(TPM) Pore structure Cement-based Accuracy Resolution

The interaction between KIF21A and KANK1 regulates dendritic morphology and synapse plasticity in neurons

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Neural Regeneration Research 2025年第1期20卷 209-223页

作者： Shi-Yan Sun Lingyun Nie Jing Zhang Xue Fang Hongmei Luo Chuanhai Fu Zhiyi Wei Ai-Hui Tang Hefei National Research Center for Physical Sciences at the Microscale CAS Key Laboratory of Brain Function and DiseaseMinistry of Education Key Laboratory for Membrane-less Organelles and Cellular DynamicsDivision of Life Sciences and MedicineUniversity of Science and Technology of ChinaHefeiAnhui ProvinceChina Institute of Artificial Intelligence Hefei Comprehensive National Science CenterHefeiAnhui ProvinceChina CAS Center for Excellence in Molecular Cell Sciences Division of Life Sciences and MedicineUniversity of Science and Technology of ChinaHefeiAnhui ProvinceChina Department of Neurobiology School of Life SciencesSouthern University of Science and TechnologyShenzhenGuangdong ProvinceChina Brain Research Center Southern University of Science and TechnologyShenzhenGuangdong ProvinceChina

Morphological alterations in dendritic spines have been linked to changes in functional communication between neurons that affect learning and ***-4 KIF21A helps organize the microtubule-actin network at the cell cortex by interacting with KANK1;however,whether KIF21A modulates dendritic structure and function in neurons remains *** this study,we found that KIF21A was distributed in a subset of dendritic spines,and that these KIF21A-positive spines were larger and more structurally plastic than KIF21A-negative ***,the interaction between KIF21A and KANK1 was found to be critical for dendritic spine morphogenesis and synaptic *** of either KIF21A or KANK1 inhibited dendritic spine morphogenesis and dendritic branching,and these deficits were fully rescued by coexpressing full-length KIF21A or KANK1,but not by proteins with mutations disrupting direct binding between KIF21A and KANK1 or binding between KANK1 and *** down KIF21A in the hippocampus of rats inhibited the amplitudes of long-term potentiation induced by high-frequency stimulation and negatively impacted the animals’cognitive *** together,our findings demonstrate the function of KIF21A in modulating spine morphology and provide insight into its role in synaptic function.

关键词： actin cytoskeleton dendrite KANK1 KIF21A microtubule spine morphology spine synaptic plasticity talin1

Enantio-divergent C–H borylation with two different ligands from a single chiral source

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Science China Chemistry 2025年第1期 226-232页

作者： Rongrong Du Senmiao Xu State key laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical Physics Chinese Academy of Sciences College of Material Chemistry and Chemical Engineering Key Laboratory of Organosilicon Chemistry and Material TechnologyMinistry of Education Hangzhou Normal University University of Chinese Academy of Sciences

Reported here is an iridium-catalyzed enantio-divergent C（sp3）–H borylation of α-gem-dimethyl groups of trifluoromethyl ketone-derived hydrazones to construct a series of acyclic all-carbon quaternary stereocenters with a high level of chiral induction. Two different chiral bidentate boryl ligands from a common chiral source not only can switch the enantioselectivity but also are complementary in terms of the substrate scope.

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