[en] A new dispersion relation for the ion temperature gradient (ITG) driven instability in toroidal plasma is derived from the reduced Braginskii equations. It includes the effects of both the safety factor q and the adiabatic electron temperature gradient η_e=d(lnT_e)/d(ln n). The present model reproduces the basic properties of ITG instability obtained by previous works. On the other hand, it is found numerically that the safety factor q enhances the ITG instabilities while the quantity η_e reduces them. (authors)

[en] A hybrid method for tokamak MHD equilibrium configuration reconstruction is proposed and employed in the modified EFIT code. This method uses the free boundary tokamak equilibrium configuration reconstruction algorithm with one boundary point fixed. The results show that the position of the fixed point has explicit effects on the reconstructed divertor configurations. In particular, the separatrix of the reconstructed divertor configuration precisely passes the required position when the hybrid method is used in the reconstruction. The profiles of plasma parameters such as pressure and safety factor for reconstructed HL-2A tokamak configurations with the hybrid and the free boundary methods are compared. The possibility for applications of the method to swing the separatrix strike point on the divertor target plate is discussed. (authors)

[en] Objective: To evaluate the clinical efficacy and cost of Histoacryl tissue adhesive in adhering the pacemaker skin wounds. Methods: During the period from April 2010 to October 2010, permanent cardiac pacemaker implantation was performed in 112 patients in authors' hospital. The patients were divided into tissue adhesive group (n=64) and conventional suture group (n=48). Histoacryl tissue adhesive was employed in patients of tissue adhesive group. The extent of wound healing, the post-procedure hospitalization days and the hospitalization cost were recorded, and the results were compared between the two groups. Results: The clinical baselines of the two groups were compatible with each other. Primary closure of wounds was achieved in all patients of two groups. The mean post-procedure hospitalization time in tissue adhesive group and in conventional suture group was (4.4±1.4) days and (6.2±1.3) days respectively, the difference between the two groups was statistically significant (P<0.01). If the costs of pacemaker equipment, surgery and DSA were not included, the mean medical expenses in tissue adhesive group and in conventional suture group were (4383.39±792.40) and (4199.81±1059.93) Chinese Yuan respectively, and no significant difference in medical expenses existed between the two groups (P=0.651). Conclusion: Histoacryl tissue adhesive can effectively adhere pacemaker wounds tissue. Compared to the use of conventional suture, the use of Histoacryl tissue adhesive can reduce the post-procedure hospitalization days although the medical expenses are quite the same as that using conventional suture treatment. (authors)

[en] Objective: to determine the feasibility and safety of transcatheter aortic valve implantation with domestic self-expandable nitinol valved stent in experimental sheep. Methods: A fresh pig pericardium was cross-linked with a 0.6% glutaraldehyde solution for 36 hours and then sutured on a nitinol self-expandable stent. Ten healthy sheep of (46.00±2.60) kg body weight were chosen for the study. Under general anesthesia, the device was delivered through catheter into the native aortic valve of the sheep via the femoral artery or abdominal aorta. The animals were followed up for three months. Results: Six devices were successfully delivered at the desired position in six sheep with no occurrence of complications. Angiographic and hemodynamic studies confirmed that the stents were fixed at correct position with competent valve function immediately and 90 days after the procedure. Technical failure or fatal complications occurred in the remaining four sheep. Conclusion: Implantation of a domestic nitinol self-expandable stent at the aortic valve position through a transcatheter approach is feasible in experimental sheep. (authors)

[en] Objective: To explore the optimal project position for demonstrating tricuspid annulus angiographically in experimental goats. Methods: Eight healthy goats underwent right atrial angiography by using 6 F pig tail catheters. Under fluoroscopic monitoring the contrast media (total 110 ml, flow rate 12 ml/ s, pressure 800 psi) was injected continuously while a serious exposures were performed from RAO position to LAO position (totally 180 degree rotation). The maximum diameter of the tricuspid annulus in every picture was measured and the results were compared with that obtained from sonography. Results: The procedure was successful in all 8 experimental goats. The optimal project position to display the tricuspid annulus was at 27 degree ± 3 degree in RAO position. Conclusion: In angiography, the tricuspid annulus can be best demonstrated at the project position of 27 degree ± 3 degree in RAO. (authors)

[en] To improve the diagnostic accuracy of pancreatic carcinoma and chronic pancreatitis. The CT findings of 154 cases with pancreatic carcinoma, chronic pancreatitis and mis-diagnosed other pancreatic diseases proven clinically and pathologically were analysed. Slice thickness of 8 mm and slice interval of 8 mm were used and thin-section scan and enhancement study were performed in some cases. The main signs in degassing and differential diagnosis between pancreatic carcinoma and chronic pancreatitis included: (1) focal or diffuse enlargement and density abnormality of pancreas; (2) dilated common bile duct was suddenly obstructed, peripancreatic blood vessels were invaded and cancerous thrombus was revealed, enlargement of abdominal lymph nodes and metastasis in the liver were discovered; (3) calcium deposit in the pancreatic duct area and dilated pancreatic duct which passed through the lesion or not; (4) presence and location of pancreatic cyst and its relationship to pancreatic contour. CT is the imaging modality of choice in the diagnosis of pancreatic carcinoma and chronic pancreatitis at present. The diagnostic accuracy of CT was over 90% in this series

[en] A general dispersion relation for fishbone mode is obtained when spatial density profile and pitch angle profile are taken into account. The fishbone modes can be driven into the second stable regime by barely passing energetic particles in high β_h region. The nonresonant fishbone mode can be induced by trapped energetic particles. Similar to the resonant fishbone modes, the nonresonant fishbone modes can also be driven into the second stable regime by trapped energetic particles and the real frequency linearly increases with increasing β_h. (authors)

[en] The fishbone instability induced by the trapped energetic electrons is studied with off-axis and on-axis ECRH in HL-2A tokamak. Numerical results show that the fishbone can be triggered by energetic electrons if the poloidal beta β_h is higher than a critical value β_h_,_c_r_i_t . In addition, its real frequency increases with the increasing of poloidal beta β_h and equals the toroidal precession frequency of energetic electrons. Furthermore, the critical value β_h_,_c_r_i_t decreases with higher density peaking of energetic electrons and approaches a constant by more peaked density profiles. And besides, analysis of the effects of the pitch angle and the turbulent energy on real frequency and growth rate is carried out. It can be seen that the growth rate curve has a local minimum value if the pitch angle α_0 = 1 , which indicates that the fishbone instability can be stabilized by the barely passing energetic particles. Moreover, it can also be seen that the real frequency increases with the increasing of the turbulent energy δŴ_c , while growth rate decreases. It indicates that the background plasma tends to stabilize the fishbone instability. (authors)

[en] In general, the energy distribution of energetic particles is bump-on-tail when both the neutral beam injection and electron/ion cyclotron resonant heating are used in tokamak plasma experiment. It is easier to induce instability for energy distribution profile with positive energy gradient regions existing such as the bump-on-tail. Therefore, a new dispersion function is introduced in dispersion relation due to bump-on-tail of the energy distribution. The calculation method of the new dispersion function is studied. T results show that the real and imaginary parts of dispersion functions are odd and even functions respectively. There are 2 to 4 extremes for real parts of the dispersion function and the positions of the extremes are dependent on ⊿, the gradient of the energy distribution, whereas there are 1 to 3 extremes for imaginary parts and the positions of these extremes are independent of ⊿. Both the real and imaginary parts of the dispersion function go to zero when the arguments of Z_t go to infinity. The calculated values agree very well with those given in dispersion function table when the bump-on-tail distribution goes to Maxwellian distribution. (authors)

[en] The EFIT (Equilibrium Fitting) code is modified for the equilibrium configuration reconstruction in HL-2A. Signals from Langmuir probe (LP) at the divertor target plates are employed in the reconstruction of divertor configurations. The results show that discharge no. 2895 starts with a limiter configuration and develops gradually into a divertor configuration after t = 230 ms. This transition process is clearly demonstrated by the LP signals for the reconstruction. The profiles of plasma parameters such as safety factor q, pressure and current density as well as the evolution of major shape parameters of plasma, such as the boundary magnetic fluxes, the positions of both x-point and magnetic axis, are calculated from the reconstructed configurations. The possibility to apply the method to the swing of strike point on the target plate is discussed. (magnetically confined plasma)