A SINGLE STEP SCHEME WITH HIGH ACCURACY FOR PARABOLIC PROBLEM

A single step scheme with high accuracy for solving parabolic problem is proposed. It is shown that this scheme possesses good stability and fourth order accuracy with respect to both time and space variables, which are superconvergent.

Single-Step Combined Laparoscopic Management of Hepatocellular Carcinoma with Simultaneous Radio Frequency Ablation and Trans-Arterial Embolization in Unresactable Lesions

Hepatocellular carcinoma (HCC) is a cancer with increasing incidence in the USA and high mortality rate. HCC is often difficult to treat due to underlying comorbidities such as cirrhosis. However, the application of loco-regional thermal ablation using radio frequency (RF) and trans-arterial embolization with chemotherapy (TACE) or without (TAE) has shown promising results in the treatment of patients not amenable to surgical resection or liver transplantation. Conventionally, RF and TAE are performed in two separated sessions or two steps and often RF ablation is performed percutaneously. However, no consensus has been reached regarding the ideal interval between the two treatments. In this article, we discuss the feasibility and benefits of a single-step TAE in combination with laparoscopic RF ablation in one operative session. We also present a case where this procedure has been successfully performed demonstrating its feasibility. We suggest that the use of laparoscopic RF ablation in the same surgical session as TAE is feasible and potentially offers several advantages over the two-step process that is usually performed with embolization followed by percutaneous RF with a long time interval. In this article we discuss such advantages.

Nano-scale gap filling and mechanism of deposit-etch-deposit process for phase-change material

Ge2Sb2Te5 gap filling is one of the key processes for phase-change random access memory manufacture. Physical vapor deposition is the mainstream method of Ge2Sb2Te5 film deposition due to its advantages of film quality, purity, and accurate composition control. However,the conventional physical vapor deposition process cannot meet the gap- filling requirement with the critical device dimension scaling down to 90 nm or below. In this study, we find that the deposit-etch-deposit process shows better gap-filling capability and scalability than the single-step deposition process, especially at the nano-scale critical dimension. The gap-filling mechanism of the deposit-etch-deposit process was briefly discussed. We also find that re-deposition of phase-change material from via the sidewall to via the bottom by argon ion bombardment during the etch step was a key ingredient for the final good gap filling. We achieve void-free gap filling of phase-change material on the 45-nm via the two-cycle deposit-etch-deposit process. We gain a rather comprehensive insight into the mechanism of deposit-etch-deposit process and propose a potential gap-filling solution for over 45-nm technology nodes for phase-change random access memory.

A compact bimorph rotary piezoelectric actuator with customized small power supply

Inertial piezoelectric actuators are widely applied in precision devices with simple structure and accurate movement.However,existing inertial piezoelectric actuators still face the challenges of rollback motion and bulky power supply.In this work,an alternate excitation strategy and a customized small power supply for a bimorph rotary piezoelectric actuator(BRPA)are proposed to solve the problems.The BRPA prototype is designed with a bipedal symmetrical structure,measuring 35 mm in height and 32 mm in diameter,which has a maximum rotation velocity of 0.247 rad/s and a resolution of 0.66μrad.Thanks to the bipedal symmetrical structure,the friction directions between the driving feet and the rotor can be coordinated to suppress the rollback.The rollback ratio is almost zero when the phase difference of the exciting signal is set as 180°.The customized power supply is designed and manufactured,whose size is 58 mm×56 mm×46 mm.It can output signals for the single step mode and the continuous mode,and they are adopted to excite BRPA to achieve a small stroke with one single step and a large stroke with continuous step,respectively.Then,an experimental system for optical fiber alignment is developed based on the BRPA and the customized small power supply,the experiment has verified the practicability of this work in the precision fields,especially in the miniaturized precision systems.

Fabrication of coconut shell-derived porous carbons for CO_(2) adsorption application

Biomass-derived porous carbons have been considered as the most potential candidate for effective CO_(2) adsorbent thanks to being widely-available precursor and having highly porous structure and stable chemical/physical features.However,the biomass-derived porous carbons still suffer from the poor optimization process in terms of the synthesis conditions.Herein,we have successfully fabricated coconut shell-derived porous carbon by a simple one-step synthesis process.The as-prepared carbon exhibits advanced textual activity together with well-designed micropore morphology and possesses oxygen-containing functional groups(reached 18.81 wt%)within the carbon matrix.Depending on the different activating temperatures(from 700 to 800℃)and KOH/biomass mass ratios(from 0.3 to 1),the 750℃ and 0.5 mass ratio were found to be enabling the highest CO_(2) capture performance.The optimal adsorbent was achieved a high CO_(2) uptake capacity of 5.92 and 4.15 mmol·g^(−1) at 0 and 25℃(1 bar),respectively.More importantly,as-prepared carbon adsorbent exhibited moderate isosteric heat of adsorption and high CO_(2)/N_(2) selectivity.The results were revealed not only the textural feature but also the surface functional groups critically determine the CO_(2) capture performance,indicating coconut shell-derived porous carbon has a considerable potential as a solid-state adsorbent for the CO_(2) capture.

Long-term stability of transparent n/p ZnO homojunctions grown by rf-sputtering at room-temperature

ZnO-based n/p homojunctions were fabricated by sputtering from a single zinc nitride target at room temperature on metal or ITO-coated glass and Si substrates.A multi-target rf-sputtering system was used for the growth of all oxide films as multilayers in a single growth run without breaking the vacuum in the growth chamber.The nitrogen-containing films(less than 1.5 at.% of nitrogen)were n-type ZnO when deposited in oxygen-deficient Ar plasma(10%O_(2))and p-type ZnO when deposited in oxygen-rich Ar plasma(50%O_(2)).The all-oxide homojunction ITO/n-ZnO/p-ZnO/ITO/glass was fabricated in a single deposition run and exhibited visible transparency in the range of 75-85%.The n/p ZnO homojunctions,having metallic contacts,formed on conventionally processed substrates showed a fairly unstable behavior concerning the current-voltage characteristics.However,the same homojunctions formed on Si_(3)N_(4)-patterned substrates and stored in atmosphere for a period of five months were stable exhibiting a turn-on voltage of around 1.5 V.The realization of a room temperature sputtered transparent and stable ZnO homojunction paves the way to the realization of all-oxide transparent optoelectronic devices.