Archive of Medical Research

[Measurement of N2+ rotational temperature in air dielectric barrier discharge]

The rotational lines of the first negative band system of N2+ were observed in air dielectric barrier discharge by using liquid electrodes. The rotational temperature was estimated by the J number of the lines with the maximum intensity in rotational spectrum. The rotational temperature was kept at a constant with increasing the applied voltage when the gas pressure was in the range of 10.133-60.795 kPa. The results are of great importance to the model foundation and the application of dielectric barrier discharge in air.

Dong LF, Li YH, Chen WJ, Li XC.

College of Physics Science and Technology, Hebei University, Baoding 071002, China. Donglf@mail.hbu.edu.cn

[Measurement and analysis of discharge current in dielectric barrier glow discharge at atmospheric pressure]

Dielectric barrier discharge has become a hot issue in low temperature plasma research field because of wide prospect for its application in industry. In the present paper, an uniform glow discharge was realized in atmospheric pressure helium with a parallel planar dielectric barrier discharge device and an uniform plasma was generated in helium at atmospheric pressure. Electrical method was used to separate the discharge current from the total current signal and the waveform of discharge current could be obtained. The relations among the discharge current, applied voltage, gap voltage and wall charge during the uniform glow discharge were used to analyze the dynamical behavior of wall charges during their accumulation. The results show that the wall charges were mainly accumulated during the existence of discharge current pulse, while the quantity of wall charges continued to increase until the gap voltage changed its polarity after the disappearance of discharge current pulse, and finally the quantity of wall charges decreased until the next breakdown. These experimental results are important for the further study of wall charges\’ effect in the dielectric barrier glow discharge and its application in industry.

Li XC, Yin ZQ, Pang XX, Li YH, Gao RL.

College of Physics Science and Technology, Hebei University, Baoding 071002, China. xcli@mail.hbu.edu.cn

[Synthesis and characterization of broadband IR-to-visible upconversion material caS : Ce, Sm by low-temperature combustion synthesis method]

Broadband IR-to-visible upconversion material CaS : Ce, Sm was synthesized for the first time by the low-temperature combustion synthesis (LCS) method. The effect of the rare earth dopant concentration on the upconversion properties was studied. XRD analysis shows that the sample features the cubic CaS crystal structure. The excitation spectrum of the sample is in the range of 200-500 nm, i. e. ultraviolet light or the visible light can excite the sample effectively to complete the \”charged\” process, and the excitation effect of the visible light is dominant. The IR sensitivity spectrum of the sample is in the range of 800-1 400 nm, indicating that CaS : Ce, Sm possesses the broadband IR-to-visible upconversion effect. The IR-to-visible upconversion spectrum of the sample is a broadband spectrum in the range of 450-650 nm, with two adjacent emission peaks at 513.4 and 572 nm, resulting from the transitions of Ce3+2T2g(5d)–>2F5/2 (4f) and the transitions of Ce3+2T2g(5d)–>2F7/2 (4f), respectively.

Zhang XY, Lu LP, Bai ZH, Wang XC, Liu QS, Mi XY.

School of Materials Science and Engineering, Changchun University of Science and Technology, Changchun 130022, China. xiyzhang@126.com

[Spectrum studies of ignition characteristic in quick reaction of benzene]

A new optical spectroscopy system consisting of a monochromator, photomultiplier tubes (PMT), piezoelectric pressure sensor and digital phosphor oscilloscope was established to study spectrum and ignition delay time of benzene in quick reaction in a high temperature shock tube. A new method of determining ignition delay time of energetic materials behind incident shock wave is proposed. Several important products, such as H, C2 and CH, were determined in sequence of emergence time. The reaction mechanism of formation of carbon was introduced when benzene was driven under shock compression. The results indicate that in spite of the variety of Mach number, atom H always emerged first, indicating that the pyrolysis of benzene started with C-H bond instead of C-C bond. The results show that applying spectrum techniques can preferably study the ignition characteristic of benzene in quick reaction. Measuring ignition delay time by means of a prior emerged intermediate product (atom H) is more accurate than that with white color technique widely used home and abroad, and furthermore, can obviously reduce the times of experiment.

Wu JH, Yan ZX, Ye S, Hu D, Yang XD.

Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China.

[Mixing and quenching of Rb 5PJ states induced by collisions with He atoms and N2 molecules]

The collisional energy transfer process Rb(5PJ)+M, where M= He, N2, under gas cell conditions has been investigated. The Rb(5P3/2) state was excited by a diode laser. The direct 5P3/2–>5S1/2 fluorescence and the sensitized 5P1/2–>5S1/2 fluorescence as a function of quenching gas pressure were measured. The 5P3/2 and 5P1/2 states are separated by 238 cm(-1). The closest other states are >6500 cm(-1) or >28 KT. Neglect of these other states should be an excellent approximation. In the experiment the Rb density was 4.5 x 10(11) cm(-3). Using radiation trapping theory the effective radiative rate=Gammae5P3/2–>5S1/2 2.47 x 10(7) s(-1) was obtained. For quenching by He only electronic to translational energy transfer is possible. However, in the N2 case, electronic to vibrational or rotational transfer is important. The Rb(5P3/2) state is 13 cm(-1) lower than the N2[X\’Sigmag+ (V= 5, J= 11)]state; this energy gap is near resonant. The authors have not attempted to directly observe this possible E-R quenching channel Using a two-state rate equation model the transfer rate coefficients from Rb(5PJ) were obtained. The rate coefficient (k21He) for 5P3/2–>5P1/2 transfer in collision with He is 2.61 x 10(-12) cm3 x s(-1). By comparing the direct and sensitized fluorescence intensities for He and N2 case, and fitting the experimental results to the rate equation analysis, the authors estimate that the rate coefficient (k21N2) for 5P3/2-5P1/2 transfer in collision with N2 is 2.36 x 10(-11) cm3 x s(-1). The E-V quenching rate coefficient (kN2) of the 5PJ state is 1.44 x 10(-10) cm3 x s(-1). The authors found find that the rate coefficient kN2 is about 6 times larger than the k21N2. The assumption that the Cs-N2 energy transfer occurs primarily in collinear collision geometry is supported. The results are discussed in relation to those of other experiments.

Meng FX, Qin C, Dai K, Shen YF.

Department of Physics, Xinjiang University, Urumqi 830046, China.

[Spectral characteristics of optical storage material CaS : Eu, Sm]

As a typical optical storage material, CaS : Eu, Sm powders were prepared by wet method in a reduced atmosphere. XRD, emission spectrum, excitation spectrum, photostimulated spectrum, thermal spectrum, and decay curve were measured. The XRD indicates that the lattice of CaS : Eu, Sm was formed at 1050 degrees C. Spectra analysis results show that UV can excite the sample as an information input source. When excited by ultraviolet lamp and then stimulated by 980 nm laser, the same luminescence with peaks at 635 nm. The photostimulated emission decayed rapidly at first and then slowly. The trap level is deep and can make electrons stable in the trap. The optical storage mechanism of CaS : Eu, Sm is discussed.

Jiang WW, Xu Z, Zhang XY.

Institute of Optoelectronics Technology, Beijing Jiaotong University, Key Laboratory of Luminescence and Optical Information, Ministry of Education, Beijing 100044, China. rosejiangwei@126.com

[Spectral power distribution and quantum yield of Sm3+-doped bismuth tellurite glass under the excitation of violet LED]

A new method for measuring the spectral power distribution in Sm3+-doped bismuth tellurite glass with higher refractive index and lower phonon energy by using integrating sphere was introduced and designed for the first time. Fluorescence measurement system was constituted by integrating sphere of 10-inch diameter, which was connected to a DDC detector. A standard halogen lamp was used to calibrate the measurement system and the auxiliary standard halogen lamp was employed for collating inner change in integrating sphere. The total radiant flux, total luminous flux and total quantum yield were calculated by luminous flux distribution and photon distribution, which were derived from spectral power distribution, and the values were 55 microW, 0.02 lm and 4.07%, respectively. In the present paper, the integrating sphere-method was applied to measure the luminescence parameters of the multichannel transition emissions in Sm3+, and it was considered as an accurate way to characterize luminescence parameters for luminescence and laser material.

Wang XY, Lin H, Li CM, Yang DL, Tanabe S.

Faculty of Chemical Engineering and Materials, Dalian Institute of Light Industry, Dalian, China.

[Effect of quercetin on proliferation and apoptosis of human nasopharyngeal carcinoma HEN1 cells]

OBJECTIVE: To investigate the effect of quercetin (Que) on HEN1 cells, a kind of human nasopharyngeal carcinoma cells. METHOD: Inhibition rate of quercetin on HEN1 was assayed by MTT method, cell apoptosis by flow cytometry (FCM), Caspase-3 expression of each group were determined by colorimetry set. RESULT: The inhibition of quercetin on HEN1 cells was shown in the dose-dependent (r = 0.709, P < 0.05) and time-dependent manner (r = 0.703, P < 0.01). The ratio of apoptotic and necrosis cells increased accompanied with added quercetin concentration. Cell cycle was specificly arrested inG2/M phase. Apoptosis cusp was revealed by FCM. While the activity of caspase-3 were also significantly upregulated in five groups after quecetin compared to control (P < 0.05). CONCLUSION: Quecetin can activate the expression of Caspase-3 and induce the apoptosis of HEN1 cells through mitochondrion-depended pathway.

Zhang F, Cui Y, Cao P.

Department of Otorhinolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China. lhkzhangfeng@163.com

[Resection of nasopharyngeal angiofibroma using by midfacial degloving approach and modified maxillotomy]

OBJECTIVE: To explore the feasibility of treatment on angiofibroma patients with stage III, IV by midfacial degloving approach and modified maxillotomy. METHOD: From Feb. 2001 to Aug. 2004, midfacial degloving approach and modified maxillotomy was used for treating 7 angiofibroma patients with stage III, IV. Using Fisch stage: Five cases were in stage III, 2 cases were stage IV; 2 cases with stage III accepted midfacial degloving approach and modified maxillotomy. Five cases accepted midfacial degloving approach and Le fort I approach (stage III, 3 cases; stage IV, 2 cases). One patient accepted the combined therapy of facial approach and cranium approach. 6 cases accept the embolizion of the artery which feed the tumor (2 cases in stage IV, 4 cases in stage III). RESULT: The blood loss was (600 +/- 324) ml in operation, the blood loss in operation of patients with selective preoperative embolization was (483 +/- 165) ml. The blood loss of one case with no selective preoperative embolization was 1300 ml. The operating time was 129 +/- 22 min. The pathology of 7 cases was nasopharyngeal angiofibroma. For 30 to 72 months follow-up, No tumor recurrence were observed, one case in stage III accepted the selective preoperative embolization got the tumor recurrence 1 year after the surgery. After the second surgery, no tumor recurrence were seen till now. CONCLUSION: For the patients in stage III, IV, midfacial degloving approach and modified maxillotomy is not only good for radical excision, decurtating the operating time and blood loss, but also good for the cosmetic outlook and functional recovery. The selective preoperative embolization has a good significance on reducing the operating blood loss and tumor recurrence rate.

Sun W, Huang X, Zheng Y, Peng J, Zou H.

Department of Otorhinolaryngology-Head and Neck Surgery, 2rd Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510120, China.

[Clinico-pathological study of contralateral lymph node metastasis in pyriform sinus carcinoma]

OBJECTIVE: To study the related factors of contralateral lymph node metastasis in pyriform sinus carcinoma. METHOD: Fifty-three patients with pyriform sinus carcinoma underwent simultaneous neck dissection from Oct. 1993 to Oct. 1999 were collected. Transparent lymph node selection and continuous slicing method were used on the postoperative specimens to observe the status of cervical lymph node metastasis. The relationship between contralateral lymph node metastasis and clinico-pathological factors, ipsilateral neck metastatic status were analyzed by the follow-up data. RESULT: Cervical lymph node metastatic rate was 79.2% in 53 patients with pyriform sinus carcinoma. Contralateral cervical lymph node metastatic rate was 35.8%. Contralateral neck metastasis was closely related with clinical N stage, cell differentiation, fused metastasis and extracapusular spread of ipsilateral neck. CONCLUSION: Contralateral neck dissection should be undertaken in patients with N2,3, moderate and low cell differentiation, or fused fused metastasis and extracapusular spread of ipsilateral neck.

Guan C, Liu B, Ji W.

Department of Otolaryngology, First Affiliated Hospital of China Medical University, Shenyang, 110001, China. guanchao999@hotmail.com