Vol.15,

Nanomanipulation of DNA molecules or other biomolecules to form artificial patterns or structures at nanometer scale has potential applications in the construction of molecular devices in future industries. It may also lead to new insights into the interesting properties and behavior of this fantastic nature-selected molecule at the single-molecular level. Here we present a special method based on the combination of macroscopic "molecular combing" and microscopic "molecular cutting" to manipulate DNA molecules and form complex patterns at nanometer scale on solid surfaces. A possible strategy for ordered DNA sequencing based on this nanomanipulation technique has also been proposed.

516

By using a microscopic sdIBM-2+2q.p. approach which is the phenomenological core plus two-quasi-particle model and the experimental single-particle energies, the levels of the ground-band, β-band, γ-band, and partial two-quasi-particle states on ^64~68 Ge isotopes are successfully reproduced. Based on the phenomenological model and microscopic approach, it has been deduced that no s-boson in the nucleus is breaking up and aligning; and that when one d-boson does, the minimum aligned energy can be calculated. This paper explicitly indicates that, with the increase of neutron number, an evolution process of PPT objectes, i.e. from the two-quasi-proton states (on ⁶⁴ Ge nucleus) to the two-quasi-neutron states (on ⁶⁸ Ge nucleus) may take place in even Ge isotopes.

429

A new neutron-rich isotope ¹⁹⁷Os was produced in the ¹⁹⁸Pt(n, 2p) reaction by irradiating natural Pt targets with 14 MeV neutrons. The γ(X) singles spectrum and coincidence spectrum measurements were performed using two HPGe γ-ray detectors. Ten unknown γ-rays at 41.2, 50.7, 196.8, 199.6, 223.9, 233.1, 250.2, 342.1, 403.6, and 460.4 keV attributed to the decay of ¹⁹⁷Os were observed in the experiments. The half-life of ¹⁹⁷Os was found to be (2.8 ± 0.6) min. A partial decay scheme of ¹⁹⁷Os was proposed on the basis of decay and coincidence relations. The half-life was compared with the values expected by different theoretical models.

387

Natural zircon was used as precursor material to produce a zircon waste form bearing 20wt% simulated actinides (Nd₂O₃ and UO₂) through a solid state reaction by a typical synroc fabrication process. The fabricated zircon waste form has relatively good physical properties (density 5.09g/cm³, open porosity 4.0%, Vickers hardness 715kg/mm²). The XRD, SEM/EDS and TEM/EDS analyses indicate that there are zircon phases containing waste elements formed through the reaction. The chemical durability and radiation stability are determined by the MCC-1 method and heavy ion irradiation; the results show that the zircon waste form is highly leach resistance and relatively stable under irradiation (amorphous dose 0.7dpa). From this study, the method of using a natural mineral to solidify radioactive waste has proven to be feasible.

428

Skeletal derangements occur quite often in patient with primary hyperparathyroidism (PHPT). We investigated parathyroid and bone imagings in 59 cases of pathologically proven PHPT. Forty-nine cases were pathologically proven parathyroid adenomas; 8 presented hyperplasia and the other 2 were adenocarcinomas. Parathyroid imaging (early phase imaging, EPI) was conducted at 30 min after injecting 740~925MBq ^99mTc-MIBI and 2~3h later (delayed phase imaging, DPI) separately. The following thyroid imagings were performed at the same posture 10 min after intravenous injection of 74~111MBq ^99mTcO₄^-. The ^99mTc^- MIBI subtraction imaging data were obtained by subtracting thyroid imaging from that of DPI. Among 49 cases of proven hyperparathyroid adenoma 45 yielded positive imagings. Eight cases with hyperplasia gave negative results. The results were positive in 2 cases of parathyroid adenocarcinoma. Results of ^99mTc-MDP/bone imaging: 35 cases of hyperparathyroid adenocarcinoma (disease duration 1-6 months) showed normal bone images, while 14 cases showed superscan images, course being 4~12 months. Bone imaging for 2 cases of adenocarcinoma showed multiple, radioactive aggregated foci (brown tumor imaging); course lasting 10~24 months. The results of bone imaging in 8 cases of hyperplasia/ hyperparathyroidism were normal. It was concluded that diagnostic accuracy for parathyroid was 79.6% and for parathyroid adenoma was 91.8%, and the technique has no diagnostic value for hyperplasia. The ^99mTc-MDP / bone imaging results for PHPT can be classified into three categories, i.e. normal, superscan and brown tumor. The imaging results correlated well with the different categories and degrees of bone damage, the duration of clinical course and the pathological types. Therefore, it's important to use bone imaging data in association with therapy to reflect the stage and progress of PHPT.

458

To evaluate the role about prevention of shunt stenosis after transjugular intrahepatic portosystemic stent shunt (TIPSS) by ¹⁰³Pd stents, ¹⁰³Pd stents and general stents are placed respectively in 18 healthy swines after TIPSS. Angiography, pathological dissection and inspection of lumen area by light microscope are made respectively in the two groups at 4 and 8 weeks after TIPSS. Portal angiography showed that stenosis occured in 2 cases of the radiation group and 3 cases in the control group at 4 weeks. Occlusion was found in all of the radiation group and part stenosis appeared in 2 cases of the radiation group and 3 cases in control group at 4 weeks. Occlusion existed in all of the radiation group and part stenosis appeared in the control group at 8 weeks. Thickness of vascular wall of hepatic vein segment in scope of stents is (3.64±1.01) mm for the radiation group (12.95MBq) and (2.24±1.02) mm for the control group. Difference between two groups is evidenced (p<0.05). 9.25~12.95MBq ¹⁰³Pd stents can not prevent stenosis after TIPSS.

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A new kind of gas detector based on gas electron multiplier (GEM) is studied for X-ray imaging of high luminosity. A single-GEM device is designed to test the property of GEM foil .The effective gain and counting capability of a double-GEM detector are measured by an X-ray tube with Cu target. An initial X–ray imaging experiment is carried out using a triple-GEM detector and the position resolution of less than 0.1mm is achieved. The 3D distribution of electrostatic field of GEM mesh is also presented.

538

Due to the multiscale character of wavelet transform, the method of wavelet transform de-noising (WTDN) is introduced. The WTDN method neither requires extra limit of frequency range for the processed signal, nor needs a prior estimate of impulse response for an identified system, so it is especially suitable to de-noise the wide-band signal and the impulse response of a blind system. The numerical simulation results indicate that the WTDN method is reliable. The WTDN method was used to process the sampled data from a preamplifier coupled to a gas detector. The experimental results also show that the WTDN method can effectively improve the SNR of sampled data and enhance the accuracy in pole identification of the system.

385

The PF (Poloidal Field) control system is one of the most important control systems in HT-7 Tokamak. Most of parameters such as plasma current, plasma horizontal position and plasma vertical position will be monitored. For the purpose of long-pulse discharge and the more precise control to plasma, the real-time operation system VxWorks is applied, instead of the behindhand and unbefitting DOS operation system. This paper describes the development process of HT-7 PF control system based on VxWorks on Intel X86 platforms. The method of using hardware cards in VxWorks, and the network communication with other operation systems are discussed especially. Results of the comparison between VxWorks and DOS operation systems are given too.

920

Fundamental characteristics of the plastic-scintillating fiber (PSF) for wide energy range of electromagnetic radiation (X & γ) have been studied to evaluate possibility of using the PSF as an imaging detector for industrial purposes. Monte-Carlo simulation program (GEANT4.5.1, 2003) was used to generate the data. In order to evaluate image quality of the detector, fiber array was irradiated under various energy and fluxes. Signal to noise ratio (SNR) as well as detector quantum efficiency (DQE) were obtained.

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A special visible experiment facility has been designed and built, and an observable experiment is performed by pouring one or several high-temperature particles into a water pool in the facility. The experiment result has verified Yang's evaporation drag model, which holds that the non-symmetric profile of the local evaporation rate and the local density of vapor would bring about a resultant force on the hot particle so as to resist its motion. However, in Yang's evaporation drag model, radiation heat transfer is taken as the only way to transfer heat from hot particle to the vapor-liquid interface, and all of the radiation energy is deposited on the vapor-liquid interface and contributed to the vaporization rate and mass balance of the vapor film. In improved model heat conduction and heat convection are taken into account. This paper presents calculations of the improved model, putting emphasis on the effect of hot particle's temperature on the radiation absorption behavior of water.

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