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Described herein are the first total syntheses of (±)-dracocephalone A (1) and (±)-dracocequinones A (4) and B (5). The synthesis was initially envisioned as proceeding through an intramolecular isobenzofuran Diels-Alder reaction, a strategy that eventually evolved into a Lewis acid-promoted spirocyclization. This highly diastereoselective transformation set the stage for trans-decalin formation and a late-stage Suárez oxidation that produced a [3.2.1] oxabicycle suited for conversion to 1. Brønsted acid-mediated aromatization, followed by a series of carefully choreographed oxidations, allowed for rearrangement to a [2.2.2] oxabicycle poised for conversion to 4 and 5.

Energy-resolved mass spectroscopy was used to investigate differences in ion-bombardment characteristics during conventional reactive magnetron sputtering of TiN films and their deposition using a grid-assisted magnetron system with anode at a high potential (up to 350 V relative to grounded chamber walls). Narrow ion energy distributions with a maximum corresponding to the ion energy close to 100 eV were obtained for the conventional magnetron deposition on a biased substrate ( V b =−100 V) in an 80%Ar+20%N 2 gas mixture at a pressure of 0.5 Pa. On the contrary, the energy distributions of ions bombarding a grounded substrate in the grid-assisted modified magnetron system with the grid potential V g =+100 V were broadened and extended to higher energies (up to 300 eV) under the same conditions. The change in the ion energy distributions is caused by increase in the plasma potential due to the high anode potential (approximately 320 V in this case). Simultaneously, the total ion flux to the substrate decreased 5.4 times compared with the conventional system. A combined effect of the enlarged kinetic energy of ions and their substantially reduced flux resulted in production of high-quality, densified TiN films with a smooth surface.

The Ti film deposited by grid-attached magnetron sputtering possesses mirror-like surface RMS roughness of 0.6∼1.3 nm. On the other hand, Ti film deposited by conventional magnetron sputtering possesses a steeply increased RMS surface roughness of 6 nm. The cross-sectional TEM micrographs indicated that Ti coating by conventional process was composed of large columnar structures. But Ti coating using two grid-attached magnetron type had a fine structures. By introducing a grid, the energy spectra of ions were characterized by a more extended high energy tail as compared to conventional magnetron sputtering. Therefore, more energetic ion bombardment generally enhances the depositing atom mobility in the case of the grid system as compared to the conventional system.

Transparent conductive Al doped ZnO thin films were prepared on glass and polymer substrates by unipolar pulsed d.c. co-CFUBM (Closed Field Unbalanced Magnetron) sputtering at ZnO and Al targets without introducing any oxygen at room temperature. The lowest resistivity of 1.2 mΩ cm as well as the transmittance of above 84% was obtained by controlling working pressure. But the resistivity is slightly increased up to 6.8 mΩ cm with time passing due to the unstable microstructure caused by the low temperature process.

In this study, a pulsed magnetron sputtering was employed to synthesize TiN films. We deal with pulse parameters such as pulse frequency and duty cycle in argon–nitrogen plasmas. Also, optical emission spectroscopy and energy resolved mass spectrometry as an integrated plasma diagnostics was employed during synthesis of thin films. The major emission lines and time-averaged ion energy distribution functions (IEDFs) corresponding to various titanium and gas discharge species are in situ surveyed in terms of frequency and duty cycles during deposition. The corresponding surface morphology was analyzed by atomic force microscopy (AFM).

The plasma oxidation process and the corrosion resistance mechanism of oxidized (α+β) brass (63.5Cu36.5Zn) in pulsed dc oxygen plasma and Mattson's solution are reported. The brass was exposed to pulsed dc oxygen plasma with various working pressures. As increasing oxygen pressure, the ZnO layer was formed on the surface dominantly and α-brass sublayer was formed under the ZnO since Zn in the (α+β) brass diffuse to surface. These multipassive layers contribute the corrosion resistance behavior of (α+β) brass with 92.5% corrosion protection efficiency to untreated sample.

This paper presents a modification to conventional magnetron sputtering systems. The introduction of grid in front of the target increases metal ion ratio. By using optical emission spectroscopy (OES) and observing both Ti neutrals and Ti ions, the relative fraction of ion could be qualitatively extended to grid-attached magnetron sputtering as compared with the conventional magnetron system. And, experimental results clearly demonstrated that a smooth and dense TiN film with a specular reflecting surface and could be produced by grid-attached magnetron with much increased Ti ion fractions as compared to conventional magnetron. From the potentiodynamic polarization test, it was shown that the corrosion current density of TiN deposited by two grid-attached magnetron sputtering was lower than that of TiN deposited by conventional magnetron sputtering.

The spatially resolved optical emission spectroscopy of various species of a pulse DC unbalanced magnetron sputtering is studied. Ar–N2 gas mixtures are used. Emission lines corresponding to titanium cathode and gas discharge species are considered. In this study, the two-dimensional (2-D) emission profiles of the lines are measured by an ICCD camera during TiN coatings. It turns out that the 2-D emission profiles of the various lines behave differently. As a result, we obtained the surface roughness value of RMS 2.3 nm at higher pulse frequency and 3.8 nm at lower pulse duty cycle.

The plasma oxidation process and the corrosion resistance mechanism of oxidized (α+β) brass (65Cu35Zn) in pulsed dc oxygen plasma and Mattson's solution are reported. The brass was exposed to pulsed DC oxygen plasma with various pulse frequencies. When the brass was exposed to the oxygen plasma, ZnO was identified dominantly in the passive layer and α-brass sublayer was formed because Zn in the (α+β) brass diffused to the surface. These multi-passive layers contribute to the corrosion resistance behavior of (α+β) brass with 92.5% corrosion protection efficiency for the untreated sample. But as input pulse frequency decreases, it becomes more effective in corrosion resistance and has relation with surface behavior in corrosion processing.

A novel magnetron sputtering system, which included simply designed two grids between target and substrate, was developed in our laboratory for the synthesis of high-density MgO films. In order to investigate the effect of grids assisted magnetron sputtering, MgO films were deposited by conventional magnetron, one grid assisted magnetron and two grids assisted magnetron. The saturated ion current density and Mg ion fraction in MgO discharges generated by grids assisted magnetron were increased in comparison with those obtained in conventional magnetron, which means that grids assisted magnetron led to the enhancement of plasma density. As a result of microstructure analysis, grids assisted magnetron produced a higher density MgO film with smoother surface compared to that obtained in conventional magnetron.

Amorphous hydrogen-free carbon (a-C) films were synthesized by closed-field unbalanced magnetron sputtering (CFUBM). The deposition rate, structure, and mechanical properties of these films were studied as a function of applied bias voltage on substrate during deposition. The film structures were investigated in Raman spectroscopy, and surface roughness was analyzed by atomic force microscopy (AFM). The hardness and elastic modulus were evaluated by nanoindentation test. Raman analysis showed that sp 3 /sp 2 ratio in a-C films increased with increasing substrate bias voltage. a-C films deposited at a bias of −100 V exhibited a maximum hardness of 25 GPa.

Commercial polymers in thin film form were used for modification by atmospheric RF plasma. The influence of the plasma treatments using Ar and Ar+O 2 on surface energy, morphology and chemical structure of the films was investigated. It was revealed that both modifications caused surface activation of the polymer film, but they obeyed different mechanisms enhancing polymer wettability. First, surface graphitization due to argon sputtering caused hydrogen to free the surface and then reacts with oxygen in the air. Second, surface oxidation is connected with the functional group formation. The reactions of Ti with the polymer led to the simultaneous formation of TiCl 2 , TiC, Ti-oxide and they contributed to film adhesion. In comparison with Ar, the mixed Ar+O 2 RF plasma treatment was a more timesaving process and had more influences on surface activation and film adhesion.

This paper presents a modification to conventional magnetron sputtering systems. The introduction of a grid in front of the target increases metal ion ratio in the plasma. By using optical emission spectroscopy (OES) and observing both Ti neutral and Ti ion, the relative ionization could be qualitatively extended to grid-attached magnetron sputtering as compared with conventional magnetron systems. Experiments clearly demonstrate microstructural cross-sectional TEM analysis of the titanium oxide film changes from a columnar-like (anisostropic) structure to a homogenous structure (isotropic), and resulting in a high refractive index. It is believed that more energetic ion bombardment induced the structural changes in films in the case of grid-assisted magnetron sputtering.

Commercial, purified PVC films were surface-modified by Ar and mixed Ar+O2 RF plasma at atmospheric pressure. The change of surface properties was monitored by contact angle measurements. Both modifications cause surface oxidation of PVC films, which is connected with the formation of functional groups enhancing polymer wettability. This process is very fast and efficient in mixed Ar+O2 RF plasma but relatively slower during PVC exposure to Ar. The interface reactions of sputtered Ti with PVC have been studied using high resolution X-ray diffractometer and X-ray photoelectron spectroscopy. The reactions of Ti with PVC lead to the simultaneous formation of TiCl2, TiC and Ti-oxide.

Understanding the mode of transport of water vapor through the film is important for improving the moisture barrier properties of metallized porous papers. For the synthesis of Al metallized porous papers, it was carried out by DC planar magnetron sputtering with various target power densities and film thickness. To correlate film characteristics with moisture barrier properties, film properties were determined by X-ray diffraction, scanning electron microscopy, Auger electron spectroscopy and evaluations of water vapor permeability (WVP). It changed preferred orientations from Al(1 1 1) to α-Al2O3(1 1 0) reacted with thermal activated oxygen from the paper as film thickness increase and the minimum WVP mean is 2.16×10−7 g mm/m2 h kPa at 6.3 W/cm2, 2 μm and the maximum is 2.00×10−8 g mm/m2 h kPa at 1.2 W/cm2, 0.2 μm.

This paper presents a modification to conventional magnetron sputtering systems. The introduction of a grid in front of the target increases the metal ion ratio. Using OES and observing both Ti neutrals and ions, it was confirmed that the relative ionization could be qualitatively extended with grid-attached magnetron sputtering compared with a conventional magnetron system. On the other hand, the relative ionization of Ar decreased. Our results also show that the Ti films deposited by conventional magnetron exhibit (100) preferred orientation as the bias voltage increased. On the other hand, in the case of the grid-attached magnetron, the Ti films exhibit highly preferred (002) orientation with increasing bias voltage. The experiments clearly demonstrated that a dense Ti film with a smooth, specular reflecting surface can be produced using the grid-attached magnetron with increased Ti ion flux compared to the conventional magnetron.

In this work, TiNxOy thin film was deposited by a DC magnetron sputtering method as a function of oxygen flow rate. Changes of chemical states of constituent elements in the deposited films were examined by X-ray photoelectron spectroscopy analysis with the increased oxygen content. As the oxygen content increased, the peak positions of Ti2p shift to 459 (Ti2p 1 2 ) and 464 eV (Ti2p3/2) with higher valence state, respectively. The film growth orientation and microstructural characteristics were also analyzed by transmission electron microscopy. The major part of the sample was amorphous TiNxOy and the minor part was TiN(1 1 1) crystallity as seen by HRTEM image and micro-diffraction pattern. The resistivities of TiNxOy thin films were varied up to 1010 Ω cm with increasing oxygen contents. Such results allowed us to understand the close relationships between the chemical states, microstructural characteristics and the resistivities.

For the evaluation of nucleation and growth behaviors influenced by substrate properties, such structure and electrical properties, chromium nitride (CrN) films were deposited on various substrates (glass, AISI 1040 steel and Si(1 1 0)) by unbalanced magnetron sputtering. X-ray diffraction and atomic force microscopy were used to study the microstructure and grain growth as a function of deposition time. The diffraction patterns of CrN thin films deposited on Si(1 1 0) exhibited crystalline structure with highly preferred orientation of (2 0 0) plane parallel to the substrate, whereas the films deposited on glass and AISI 1040 exhibited preferred orientations (2 0 0) and minor orientation (1 1 1), (3 1 1) or (2 2 0) plane. The orientation of films deposited both on glass and Si substrates did not depend on the bias voltage ( V s ). At the same time, the crystallites of films deposited on AISI 1040 steel with the bias voltage of V s =−100 V had the orientation of (2 2 0) plane parallel to the substrate. The grain growth and structure of film deposited on AISI 1040 steel substrate are strongly influenced by the substrate bias in comparison with that deposited onto glass and Si substrates. The differences in the structure and grain growth of CrN films deposited onto different substrates are predominantly related to the properties of the substrate (structure and electrical conductivity).

Crystalline poly-Si thin films were deposited on Corning glass substrates at a temperature of 500 °C using a pulsed d.c. magnetron sputtering source. The increased bias voltage causes an enhancement of the potential difference between the plasma and substrate. In case of the bipolar pulsed d.c. magnetron sputtering, Vp shows higher value than that in the unipolar pulsed d.c. as the bias voltage increases. Therefore, the mobility of the sputtered adatoms increases by the surface heat accumulation of energetic sputtered particles with the increased bias voltage. Consequently, more higher mobility (41 cm2 Vs−1) and crystallinity were obtained for the Si film grown with the bipolar-pulsed d.c. magnetron sputtering due to the energy incorporation by enhanced bombardment of Ar ions.

Rationale: Lymphoepithelial carcinoma (LEC) is a rare malignancy with the histopathological feature of undifferentiated carcinoma and an intermixed reactive lymphoplasmacytic infiltration. Although clinically significant because of its malignant nature, it is difficult to make a differential diagnosis by preoperative imaging. Here, we report 3 cases of primary LEC arising in the major salivary glands, which showed unusual imaging features unlike other malignant tumors. Patient concerns: Our first case is a 44-year-old man with LEC in the right parotid gland, the second case is a 71-year-old woman with LEC in the right submandibular gland, and the third case is a 35-year-old woman with LEC in the right parotid gland. All of the patients presented with a palpable mass of variable duration. Diagnoses: Computed tomography (CT) scans revealed a relatively well-defined, slightly hyperattenuated exophytic solid mass that had homogeneous well-enhanced regions. Ultrasonography (US) in the first 2 cases showed well-defined, hypoechoic solid masses with posterior enhancement. The CT findings seem to be benign tumors, but US features are compatible with highly cellular and hypervascular tumors. Interventions: The resection of the involved salivary gland with postoperative radiation therapy was performed. Outcomes: There was no evidence of recurrence or metastasis after 5 years in all 3 patients. Lessons: Understanding these unusual imaging findings may be helpful in detecting LEC, and may also help clinicians provide adequate management to patients, such as surgery with adjuvant radiotherapy, because of its malignant entity.

High rate deposition of CrNx films with control of microstructure was carried out by magnetron sputtering. For these purposes, the deposition processes parameters were varied: N2 flow rate and especially substrate bias voltage, duty cycle and frequency using a pulsed DC power supply. The microstructure was analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and mechanical properties were evaluated by a microhardness test and adhesion test. The maximum deposition rate for CrNx compound films could be reached to nearly 90% compared with that for pure Cr coating due to the increase of ionization efficiency caused by a negative-pulsed DC bias. As N2 flow rate is increased, the microstructure of CrNx films was changed from Cr+Cr2N to CrN. Also, a phase transformation occurred between Cr2N+CrN multi-phase and CrN mono-phase by control of a negative DC and/or pulsed DC bias voltage, duty cycle and frequency. Microhardness for CrNx films were measured to be up to 1600 kg/mm2 and the maximum hardness value of 2250 kg/mm2 was obtained for CrNx film deposited with a N2 flow rate of 20 sccm at a negative DC bias of −100 V.

Summary form only given, as follows. It is well known that thin film growth and surface morphology can be substantially modified by ion-bombardment during the deposition. This is particularly important in case of thin-film deposition at low temperatures where the film growth occurs under highly nonequilibrium conditions. An attractive way to promote crystalline growth and surface morphology is deposition of additional energy into the surface of the growing film by bombardment with hyperthermal particles. We deposited crystalline Ti and TiN thin films on Si substrate by magnetron sputtering method with grid. Its thin films were highly smoothed and dense as increasing grid bias. In order explore the benefits of a bombardment of the growing film with high energetic particles, Ti and TiN films were deposited on Si substrates by an imbalanced magnetron sputter source with attached grid assembly for energetic ion extraction. Also, we have studied the variation of the plasma states for the feedback control of nucleation and growth behavior by Langmuir probe and Optical Emission Spectroscopy (OES). The epitaxial orientation, microstructual, optical characteristics and surface properties of the films were analyzed by XRD, SEM, ellipsometry and AFM.

Summary form only given, as follows. Summary form only given. Polymers frequently replace traditional engineering materials such as metals, glasses and ceramics. The utilization of polymers can further be enhanced by coating them by a protective layers, optical coatings, gas permeation barriers, and others. However, the desirable bulk properties of polymers are often compromised by unfavourable surface characteristics, such as low hardness, low resistance to abrasion and scratching, and low surface energy, that generally leads to poor adhesion. In our previous work, we synthesized Ti-Cu-N and Ti-Ag-N nano-composite films with various Cu and Ag contents. The hardness of Ti-Cu-N and Ti-Ag-N films could be significantly improved by addition of Cu and Ag, indicating that an appropriate amount of doping element was selected. The maximum hardness of these films reached to about 40GPa and friction coefficient was about 0.3 In our study, to overcome the film adhesion problem, we used a pretreatment of a polymer by atmospheric RF plasma After pretreatment, we have deposited Ti-Me-N, nano-composite films on polymer by magnetron sputtering. To analysis of atmospheric plasma and metal doping effect on plasma, we measured plasma states by Optical Emission Spectroscopy (OES) and Residual Gas Analyzer (RGA). The deposition rate, microstructure, surface morphology of the films were studied using /spl alpha/-step profilometer, High Resolution X-Ray Diffraction(HRXRD), Transmission Electron Microscopy(TEM) and Atomic Force Microscope(AFM). The mechanical properties of metal doped transition metal nitride films were evaluated by nano-indentation test.

Summary form only given, as follows. Magnetron sputtering is a broadly used process for coating thin films for display applications, semiconductor applications, hard coatings, decorative coatings, optical coatings, and so on. In order to enhance the film properties and deposition rate various magnetron sputtering sources have been developed such as dual magnetron sputtering, ionized magnetron sputtering, grid assisted magnetron sputtering, and so on. We have developed high efficiency magnetron sputtering sources. In this study, we investigated of spectroscopic study for ionization enhancement in the magnetron sputtering process with a solenoid coil. The sputtering cathode used in the experiment is a unbalanced magnetron sputtering source with a Ti target which is coupled with a solenoid coil. The active species were evaluated in terms of the 1st negative system and 2 nd positive system of nitrogen, Ar I (4p'-4s') and Ar II (4p-4s) by optical emission spectroscopy.