力学共振吸收谱探测耦合振动模式

提出探测复杂力学振动系统耦合振动模式的方法:通过测量力学振动系统中某一易于探测的振动模式对外力的响应行为,在该振动模式应变落后于应力的相位差-频率谱(表观机械能耗散-频率谱)中,除了能观察到与被测量振动模式本征频率所对应的相位变化外,与被测量振动模式耦合的其他振动模式也表现为共振吸收峰;从共振吸收峰的性质,如峰位、峰宽、峰高等可以得到相应耦合振动模式的本征频率、损耗以及耦合强度等信息.以倒扭摆力学系统为例,通过测量扭摆的扭转振动模式应变落后于应力的相位差-频率谱研究了扭摆系统中摆杆的进动振动模式.     

A Highly Sensitive Fluorescent Probe for HClO and Its Application in Live Cell Imaging

A new rhodamine-based probe 1 was designed and synthesized as a new fluorescent molecular probe for HClO in PBS buffer at physiological condition. The free probe 1 almost nonfluorescence, however, a drastic enhancement of fluorescence intensity was observed in the presence of HClO. The new probe 1 exhibits good sensitivity and selectivity for HClO over other reactive oxygen and/or nitrogen species in PBS buffer, and the probe was successfully applied to image endogeneous HClO in the living cells.     

Novel high-sensitivity coherent transceiver for optical DPSK/DQPSK signals based on heterodyne detection and electrical delay interferometer

We present a novel coherent transceiver for optical differential phase-shift keying/differential quadrature phase-shift keying （DPSK/DQPSK） signals based on heterodyne detection and electrical delay interferometer. A simulation framework is provided to predict a theoretical sensitivity level for the reported scheme. High sensitivity of -45.18 dBm is achieved for 2.5-Gb/s return-to-zero （RZ）-DPSK signal, and high sensitivities of -36.83 dBm （I tributary） and -35.90 dBm （Q tributary） are observed for 2.5-GBaud/s RZ-DQPSK signal in back-to-back configuration. Transmission for both signals over 100 km is also investigated. Experimental results are discussed and analyzed.     

A new method for measuring the pulse-front distortion of arbitrary shapes in high-power ultrashort laser systems

We present a new method that can be used to calculate pulse-front distortion by measuring the spectral interference of two point-diffraction fields in their overlapped district. We demonstrate, for the first time, the measurement of the pulse-front distortion of the pulse from a complex multi-pass amplification system, which exists in almost all high-power laser systems, and obtain the irregular pulse-front distribution. The method presented does not need any reference light or assumption about the pulse-front distribution, and has an accuracy of several femtoseconds.     

Room-temperature direct-bandgap photoluminescence from strain-compensated Ge/SiGe multiple quantum wells on silicon

Strain-compensated Ge/Si_0.15Ge_0.85 multiple quantum wells were grown on an Si_0.1Ge_0.9 virtual substrate using ultrahigh vacuum chemical vapor deposition technology on an n +-Si（001） substrate.Photoluminescence measurements were performed at room temperature,and the quantum confinement effect of the direct-bandgap transitions of a Ge quantum well was observed,which is in good agreement with the calculated results.The luminescence mechanism was discussed by recombination rate analysis and the temperature dependence of the luminescence spectrum.     

A new method for measuring the pulse-front distortion of arbitrary shapes in high-power ultrashort laser systems

We present a new method that can be used to calculate pulse-front distortion by measuring the spectral interference of two point-diffraction fields in their overlapped district.We demonstrate,for the first time,the measurement of the pulse-front distortion of the pulse from a complex multi-pass amplification system,which exists in almost all high-power laser systems,and obtain the irregular pulse-front distribution.The method presented does not need any reference light or assumption about the pulse-front distribution,and has an accuracy of several femtoseconds.     

Antibacterial and Synergy of Berberines with Antibacterial Agents against Clinical Multi-Drug Resistant Isolates of Methicillin-Resistant <em>Staphylococcus aureus </em>(MRSA)

Antibacterial activity of berberine (Ber) and 8-acetonyl-dihydroberberine (A-Ber) alone and combined uses with antibacterial agents ampicillin (AMP), azithromycin (AZM), cefazolin (CFZ) and levofloxacin (LEV) was studied on 10 clinical isolates of SCCmec III type methicillin-resistant Staphylococcus aureus (MRSA). Susceptibility to each agent alone was tested using a broth microdilution method and the chequerboard and time-kill tests for the combined evaluations, respectively. The alone MICs/MBCs (mg/mL) ranges were 32-128/64-256 (Ber) and 32-128/128-512 (A-Ber). Significant synergies were observed for the Ber (A-Ber)/AZM and Ber (A-Ber)/LEV combinations against 90% of the tested MRSA strains, with fractional inhibitory concentration indices (FICIs) values ranged from 0.188 to 0.500. An additivity result was also observed for the Ber/AZM combination by time-kill curves. These results demonstrated for the first time that Ber and A-Ber enhanced the in vitro inhibitory efficacy of AZM and LEV to a same extent, which had potential for further investigation in combinatory therapeutic applications of patients infected with MRSA.     

Struvite precipitation for ammonia nitrogen removal in 7-aminocephalosporanic acid wastewater

7-Aminocephalosporanic acid wastewater usually contains high concentrations of ammonium (NH??-N), which is known to inhibit nitrification during biological treatment processes. Chemical precipitation is a useful technology to remove ammonium from wastewater. In this paper, the removal of ammonium from 7-aminocephalosporanic acid wastewater was studied. The optimum pH, molar ratio, and various chemical compositions of magnesium ammonium phosphate (MAP) precipitation were investigated. The results indicated that ammonium in 7-aminocephalosporanic acid wastewater could be removed at an optimum pH of 9. The Mg2?:NH??-N:PO? 3?-P molar ratio was readily controlled at a ratio of 1:1:1.1 to both effectively remove ammonium and avoid creating a higher concentration of PO? 3?-P in the effluent. MgCl?·6H?O + 85% H?PO? was the most efficient combination for NH??-N removal. Furthermore, the lowest concentration of the residual PO? 3?-P was obtained with the same combination. Struvite precipitation could be considered an effective technology for the NH??-N removal from the 7-aminocephalosporanic acid wastewater.     

Improved properties of polymer electrolyte by ionic liquid PP1.3TFSI for secondary lithium ion battery

A new kind of polymer electrolyte is prepared from N-methyl-N-propylpiperidinium bis (trifluoromethanesulfonyl) imide (PP1.3TFSI), polyethylene oxide (PEO), and lithium bis (trifluoromethanesulfonyl) imide (LiTFSI). IR and X-ray diffraction results demonstrate that the addition of ionic liquid decreases the crystallization of PEO. Thermal and electrochemical properties have been tested for the solid polymer electrolytes, the addition of the room temperature molten salt PP1.3TFSI to the conventional P(EO)₂₀LiTFSI polymer electrolyte leads to the improvement of the thermal stability and the ionic conductivity (x = 1.27, 2.06 × 10⁻⁴ S cm⁻¹ at room temperature), and the reasonable lithium transference number is also obtained. The Li/LiFePO₄ cell using this polymer electrolyte shows promising reversible capacity, 120 mAh g⁻¹ at room temperature and 164 mAh g⁻¹ at 55 °C.     

Concerted Interaction between Pnicogen and Halogen Bonds in XCl?FH2P?NH3 (X=F,OH, CN,NC, and FCC)

We analyze the interplay between pnicogen‐bonding and halogen‐bonding interactions in the XCl? FH₂P? NH₃ (X=F, OH, CN, NC, and FCC) complex at the MP2/aug‐cc‐pVTZ level. Synergetic effects are observed when pnicogen and halogen bonds coexist in the same complex. These effects are studied in terms of geometric and energetic features of the complexes. Natural bond orbital theory and Bader’s theory of “atoms in molecules” are used to characterize the interactions and analyze their enhancement with varying electron density at critical points and orbital interactions. The physical nature of the interactions and the mechanism of the synergetic effects are studied using symmetry‐adapted perturbation theory. By taking advantage of all the aforementioned computational methods, the present study examines how both interactions mutually influence each other.