Argon Ratio Research Articles

Exploring the Stability of Azto Tfts: The Critical Role of Oxygen Partial Pressure in Performance Optimization

Amorphous oxide semiconductors, such as indium-gallium-zinc oxide (IGZO), have attracted significant attention due to their high electron mobility and low processing temperatures compared to amorphous silicon (a-Si). These characteristics make IGZO suitable for large-area applications, and its transparency holds promise for next-generation electronic devices. However, the commercialization and large-scale production of IGZO are limited by the toxicity of indium and the high cost of gallium. In this context, AZTO can emerges as a cost-effective and less toxic alternative. This study explores the fabrication and characterization of bottom-gate thin-film transistors (TFTs) using aluminum-zinc-tin oxide (AZTO) as an alternative channel material. AZTO films were deposited at room temperature via radio frequency (RF) magnetron sputtering with varying ratios of oxygen and argon. Comprehensive measurements, including temperature stress (TS), negative bias temperature stress (NBTS), activation energy, and density of states (DOS), were conducted to evaluate the electrical properties and stability of the TFTs. The results indicate that increasing the oxygen partial pressure during deposition reduces oxygen vacancies, significantly enhancing the stability of the devices. These findings highlight AZTO as a cost-effective and less toxic alternative to IGZO, particularly in display applications. Additionally, the study provides insights into the fundamental mechanisms governing the electrical behavior of AZTO-based TFTs, further confirming their suitability for advanced display technologies.

Niobium Oxide Thin Films Grown on Flexible ITO-Coated PET Substrates

Niobium oxide thin films were grown on both rigid and flexible substrates using DC magnetron sputtering for electrochromic applications. Three experimental series were conducted, varying the oxygen to argon flow rate ratio and deposition time. In the first series, the oxygen to argon ratio was adjusted from 0 to 0.32 while maintaining a constant growth time of 30 min. For the second and third series, the oxygen to argon ratios were fixed at 0.40 and 0.56, respectively, with deposition times ranging from 15 to 60 min. A structural transition from crystalline to amorphous was observed at an oxygen to argon flow rate ratio of 0.32. This transition coincided with a change in appearance, from non-transparent with metallic-like electrical conductivity to transparent with dielectric behavior. The transparent niobium oxide films exhibited thicknesses between 51 nm and 198 nm, with a compact, dense, and featureless morphology, as evidenced by both top-view and cross-sectional images. Films deposited on flexible indium tin oxide (ITO)-coated polyethylene terephthalate (PET) substrates displayed a maximum surface roughness (Sq) of 9 nm and a maximum optical transmission of 83% in the visible range. The electrochromic response of niobium oxide thin films on ITO-coated PET substrates demonstrated a maximum coloration efficiency of 30 cm2 C−1 and a reversibility of 96%. Mechanical performance was assessed through bending tests. The ITO-coated PET substrate exhibited a critical bending radius of 6.5 mm. Upon the addition of the niobium oxide layer, this decreased to 5 mm. Electrical resistance measurements indicated that the niobium oxide film mitigated rapid mechanical degradation of the underlying ITO electrode beyond the critical bending radius.

Measurements of ignition delay time of gas-to-liquid (GTL) fuel blends

The ignition delay time (IDT) is a fundamental combustion parameter of any fuel, which has a direct impact on its combustion and exhaust emissions in diesel engines. In this research, a thorough experimental study was conducted to investigate the ignition delay of Gas-to-Liquid (GTL) fuel and its 50%–50 % blends with diesel under a wide range of operating conditions using a conventional shock tube apparatus. Simultaneously, a comprehensive chemical kinetic model, based on the well-established POLIMI mechanism, was developed to simulate the complex combustion chemistry of diesel, GTL, and their blends. Several loading pressures in the driver section ranging from 6 to 14 bar that results in reflected pressure of 8–16 bar, and equivalence ratios ranging from 0.5 to 1.3 as well as different initial temperatures have been examined. Calibration of the shock tube indicated that a driver gas tailoring technique was necessary to be used, which was conducted by adding a small ratio of either argon or nitrogen to helium to get an extended test time by 32 % with a good rapture pressure. IDT measurements showed that GTL has the shorter ignition delay time than that of diesel fuel for all conditions. The findings show that IDT measurements for GTL fuel has a shorter ignition delay time than that of diesel fuel for all conditions. Under stoichiometric conditions (ɸ = 1.0), IDT of the blended fuel was about 3 ms, very close to that of GTL at 975 K. However, at a temperature above 1000 K, the IDT of the three fuels were almost identical and ranging between 1 and 2 ms. At a temperature of 1100 K, the IDT of the blended fuel was 5.5 ms, almost a middle value between those of the pure diesel, 0.522 ms, and GTL fuel, 0.495 ms. The shortest IDT of the blended fuel was about 0.4 ms with the highest value of the reflected pressure of 14 bar, while the longest IDT was around 10 ms with the rich mixture at ɸ = 1.3. The study can add to the existing literature illustrating the behavior of GTL-diesel blend can affect IDT.

Heat-Annealed Zinc Oxide on Flexible Carbon Nanotube Paper and Exposed to Gradient Light to Enhance Its Photoelectric Response.

Buckypaper (BP), a flexible and porous material, exhibits photovoltaic properties when exposed to light. In this study, we employed radio frequency (RF) sputtering of zinc oxide (ZnO) followed by rapid thermal annealing to enhance the photovoltaic response of BP. We investigated the impact of various sputtering parameters, such as the gas flow ratio of argon to oxygen and deposition time, on the morphology, composition, resistivity, and photovoltaic characteristics of ZnO-modified BP. Additionally, the photovoltaic performance of the samples under different illumination modes and wavelengths was compared. It was found that optimal sputtering conditions-argon to oxygen flow ratio of 1:2, deposition time of 20 min, and power of 100 watts-resulted in a ZnO film thickness of approximately 45 nanometers. After annealing at 400 °C for 10 min, the ZnO-modified BP demonstrated a significant increase in photocurrent and photovoltage, along with a reduction in resistivity, compared to unmodified BP. Moreover, under gradient illumination, the ZnO-modified BP exhibited a photovoltage enhancement of 14.70-fold and a photocurrent increase of 13.86-fold, compared to uniform illumination. Under blue light, it showed a higher photovoltaic response than under other colors. The enhancement in photovoltaic response is attributed to the formation of a Schottky junction between ZnO and BP, an increased carrier concentration gradient, and an expanded light absorption spectrum. Our results validate that ZnO sputtering followed by annealing is an effective method for modifying BP for photovoltaic applications such as solar cells and photodetectors.

Characteristics of the O(1S) to O(1D) 557.7 nm green emission observed in an argon plasma jet

An extensive study on the green auroral emission characterization is presented based on a single dielectric barrier discharge geometry argon plasma jet driven by a kHz sine voltage. The plasma was generated by using 99.999% pure argon and the observed 557.7 nm green line resulted from the excited O(1S) state. An optical emission spectroscopy method using line ratios of argon was used to obtain the electron density and electron temperature under different conditions in the downstream region. The characteristics of discharge and green emission with variations in interelectrode distance, applied voltage (power) and flow rate are discussed. The spatially diffuse distribution of O(1S), owing to its long lifetime, is shown by the short exposure imaging. Two discharge regimes are presented, accompanied by two distinct branches of the green emission intensity, with a clear conclusion that the 557.7 nm emission is favored in the low electron temperature environment. In this work, the intense and diffuse green plume only forms when the downstream electron density is approximately lower than 1 × 1014 cm−3 and the electron temperature is lower than 1.1 eV. By charging the two electrodes in two opposite ways, it is shown that the green emission from oxygen is favored in the case where the electric field and the electron drift are not continuous.

Efficiency and power enhancement strategies for methane direct injection argon power cycle engines

Argon Power Cycle (APC) is a novel concept for high efficiency and zero carbon emissions, which replaces the air by an argon-oxygen mixture. Previous studies have experimentally demonstrated that APC has a great efficiency enhancement potential for methane-fueled engines. However, the port methane injection tends to cause knock and limits thermal efficiency gains. In addition, few researches have focused on the power of APC methane-fueled engines. In this study, fundamental experiments are first conducted in a spark ignition methane direct injection engine with compression ratio = 9.6. Strategies such as lean combustion, dilution combustion (increasing argon mole ratio in argon-oxygen mixture), and boosting intake pressure are adopted. Results indicate that lean combustion has a more significant effect in efficiency enhancement under APC compared with air cycle due to the high specific heat ratio of argon. The combination of dilution combustion and boosting intake pressure is a feasible approach to further improve both efficiencies and powers. When argon mole ratio = 85 %, intake pressure = 0.12 MPa, and excess oxygen ratio = 1.37, the highest net indicated thermal efficiency reaches 59.0 % and the indicated mean effective pressure increases a factor of 1.61 than that at argon mole ratio = 79 % and intake pressure = 0.09 MPa. In this case, the ratio of gross indicated thermal efficiency to theoretical thermal conversion efficiency is 90.5 %. Based on thermodynamic calculation, when the ratio of gross indicated thermal efficiency to theoretical thermal conversion efficiency is assumed to be 90 %, a high net indicated thermal efficiency of 65 % is predicted to be obtained at compression ratio = 14.

Thermodynamic analysis of employing argon as the diluent and adding hydrogen in an HCCI ammonia engine: Ignition characteristics and performances of combustion and NO emissions

Ammonia is an efficient hydrogen energy carrier and a potential zero-carbon fuel for internal combustion engines. However, the poor ignition and combustion performances of ammonia limit its further application in homogeneous charge compression ignition engines. This study proposes to employ an inert gas argon as a diluent to improve ammonia's ignition and combustion performances. Furthermore, the effect of adding hydrogen is also investigated under a wide calculation range of compression ratio, excess oxygen ratio, and argon ratio through thermodynamic analysis. The calculation results indicate that replacing nitrogen with argon can significantly shorten the ignition delay time and promote the thermal conversion efficiency and power density. Under a specific condition (compression ratio = 19 and excess oxygen ratio = 3.0), when replacing air with an argon-oxygen mixture of argon/oxygen ratio = 79: 21, the ignition delay time of pure ammonia reduces from 700 ms to 0.31 ms, the thermal conversion efficiency increases from 65.1% to 78.2%, and the power density raises by approximately 20%. Nevertheless, the NO volume fraction grows by 1179 × 10−6 VOL due to the high temperature. The ignition delay time drops with the increase of hydrogen blend ratio. With an initial condition of 1250 K and 3.0 MPa, the ignition delay time decreases by 81%–95% when the hydrogen blend ratio is elevated from 5% to 20%. However, adding hydrogen also falls the thermal conversion efficiency and elevates the NO volume fraction. A hydrogen blend ratio of 5% is an excellent tradeoff value.

Knock control in hydrogen-fueled argon power cycle engine with higher compression ratio by water port injection

Hydrogen-fueled Argon Power Cycle engine is a novel concept for high efficiency and zero emissions, which chooses high specific heat ratio argon‑oxygen mixture as working fluid. However, the low specific heat of argon also increases the in-cylinder temperature, causing severe knock, which limits the efficiency of the engine. A typical knock-limited compression ratio for a hydrogen port-injected Argon Power Cycle engine is about 5.5:1 if no specific method is used. This article presents experimental research on the effect of water port injection under 1000 r/min at a compression ratio of 9.6:1 with IMEP ranging from 0.1 to 0.6 MPa and argon ratios of 79%, 85%, and 90%. The net indicated thermal efficiency peaks at 53.50% without a water injection but the knock intensity reaches 3.4 MPa. With the water injection, 16 mg/cycle water is sufficient to eliminate knock and the maximum net indicated thermal efficiency slightly reduces to 52.41%. With the water increased to 51 mg/cycle, a maximum IMEP of 0.64 MPa is achieved with an argon ratio of 85%. Argon ratio shows a marginal effect on the peak net indicated thermal efficiency, but the diagram factor is lower with higher argon ratios. At peak net indicated thermal efficiency conditions of different argon ratios, the diagram factor of Argon Power Cycle engine ranges from 76% to 80%, while a typical diagram factor of an air-breathing hydrogen engine can reach 90%. Both argon‑oxygen and air-breaching hydrogen engines can currently achieve the indicated thermal efficiency of over 52%, but the Argon Power Cycle engine shows a greater potential for further efficiency improvement. This paper suggests that the water injection is a feasible method for the knock suppression of the Argon Power Cycle engine with a marginal negative effect on efficiencies.

Future High-Efficiency and Zero-Emission Argon Power Cycle Engines: A Review

Review Future High-Efficiency and Zero-Emission Argon Power Cycle Engines: A Review Chenxu Wang , Shaoye Jin , Jun Deng , Weiqi Ding , Yongjian Tang , and Liguang Li ,* School of Automotive Studies, Tongji University, Shanghai 200092, China * Correspondence: liguang@tongji.edu.cn Received: 27 February 2023 Accepted: 23 May 2023 Published: 13 June 2023 Abstract: This paper reviews the theoretical and experimental researches on Argon Power Cycle (APC) engines. Hydrogen-fueled APC is an innovative power system for a high efficiency and zero emissions, which employs argon rather than nitrogen as a diluent. Due to the large specific heat ratio of argon, the thermodynamic efficiency of APC engines is significantly higher compared to conventional internal combustion engines. However, APC engines face the challenge of knock inhibition, especially when using hydrogen as a fuel. Therefore, this paper summarizes the strategies and technologies to suppress the knock of hydrogen-fueled APC engines, including using alternative fuels with greater anti-knock capacity, lean combustion, and water injection. Furthermore, some guidance opinions are also provided for reference about the development and industrialization of APC engines, such as ultra-lean combustion, which uses pistons with thermal insulation coatings, employing low-friction lubricants, and developing efficient multi-component membrane separation system for argon separation.

Combinatorial Synthesis of AlTiN Thin Films

Nitrides of aluminum (Al) and titanium (Ti) mixtures have long been studied and used as commercial coatings because of their high hardness and high oxidation resistance due to the formation of an alumina layer on the coating surface. To fully understand the contribution of Al and Ti to the properties of the film, a combinatorial deposition approach was employed using half-disk targets. Film growth was carried out using a magnetron sputtering system powered by a 13.56 MHz radio frequency power supply with varying argon (Ar) and nitrogen (N2) gas ratios. Depending on the location of the substrate relative to the target, atomic percent gradients of 0.60–0.70 Al and 0.30–0.40 Ti across the substrate surface were obtained from energy dispersive X-ray spectral analysis. X-ray diffraction peaks at 43.59°, 74.71° (face-centered cubic), and 50.60° (wurtzite) confirmed the presence of aluminum titanium nitride (AlTiN) mixtures, with an increasing amount of wurtzite phase at higher Al concentrations. For all samples, cauliflower-like nanograins were obtained and samples of the 80:20 Ar:N2 gas pressure ratio showed the smallest grain size among the three gas ratio combinations. The 80:20 Ar:N2 films revealed a relatively high hardness compared to the other gas ratios. All thin films exhibited good adhesion to 304 stainless steel substrates.

Controlling the flow of oxygen to explore the study of zinc tin oxide thin film transistors

本研究討論在射頻濺鍍腔體內，控制氬氣氧氣比(Ar:O2)，沉積氧化鋅錫(ZTO)薄膜，透過厚度、穿透率找到最佳條件。接著使用二氧化鉿(HfO2)作為絕緣層，製成氧化鋅錫(ZTO)電晶體，藉由測量電性進行材料分析，發現利用氮氧比為45:5的ZTO薄膜製作而成的薄膜電晶體，有很好的飽和區，臨界電壓為1.26V。<br>我們發現氧氣含量越高時，薄膜的穿透率會越來越高，在可見光的波長間穿透率有85%。再透過量測霍爾效應看出45:5的條件下有較好的載子濃度6.45x1011。原因是在氧氣濃度高的情況下，許多的氧空缺被填滿，改善了載子濃度過高的問題，進而達到飽和且截止的功能。This study discusses in the RF sputtering chamber, controlling the ratio of argon to oxygen (Ar:O2), depositing zinc tin oxide (ZTO) film, and finding the best conditions through thickness and penetration.Then use hafnium dioxide (HfO2) as an insulating layer to make zinc tin oxide (ZTO) transistors. By measuring the electrical properties for material analysis, it is found that the thin film made of ZTO film with a nitrogen-to-oxygen ratio of 45:5 is used. The crystal has a good saturation zone and the critical voltage is 1.26V.We found that the higher the oxygen content, the higher the penetration rate of the film, and the penetration rate between visible light wavelengths is 85%. Through the measurement of the Hall effect, it can be seen that the carrier concentration is 6.45x1011 under the condition of 45:5. The reason is that in the case of high oxygen concentration, many oxygen vacancies are filled, which improves the problem of excessive carrier concentration, and then achieves the function of saturation and cut-off.

In-situ synthesis of high strength and toughness TiN/Ti6Al4V sandwich composites by laser powder bed fusion under a nitrogen-containing atmosphere

Laser powder bed fusion (LPBF) additive manufacturing provides the freedom to manufacture the novel bionic structures and materials with excellent mechanical properties (e.g., combining high strength and toughness). In this work, inspired by the laminar structure of natural shells, the TiN/Ti6Al4V sandwich structural materials were fabricated in the atmosphere with different ratios of nitrogen and argon. The elemental diffusion, in-situ synthesis between N and Ti atoms, microstructure evolution, and mechanical properties of LPBF-processed TiN/Ti6Al4V sandwich composites were investigated. TiN induced by the in-situ synthesis between N and Ti atoms was observed, which exhibited an excellent metallurgical bond with the Ti6Al4V matrix. The microhardness of the TiN/Ti6Al4V layer varied from 409.62 HV0.2 and 442.55 HV0.2 with different nitrogen concentrations. The tensile strength and ductility of LPBF-processed TiN/Ti6Al4V sandwich composite parts were enhanced by the combination of bio-inspired lamellar structure and internal ceramic particle reinforcement. Interlayer hard-soft phase combination in the composite parts could be contributed to the excellent mechanical properties with an ultimate strength of 1303.12 MPa and a plastic strain of 8.9%. This study demonstrates that a flexible combination of the LPBF process and reactive atmosphere can in-situ additive manufacture the novel periodic lamellar ceramic/metal heterogeneous materials with excellent mechanical performance (e.g., rigid, wear-resistant, corrosion-resistant and toughness).

Rotating spoke frequency in E × B penning source with two-ion-species plasma

In E B sources with different degrees of magnetization between electrons and ions, collisionless Simon–Hoh instability is prone to be induced, which may result in long-wavelength and low-frequency plasma oscillations along the azimuthal direction known as the rotating spoke. Recent studies have shown that the inertial response of unmagnetized ions is a key factor that affects the rotating spoke frequency, and in-depth studies on the correlation between the ion mass and spoke frequency have been conducted for various types of E B sources (e.g. Hall thruster, magnetron and Penning sources). In the case of the E B Penning source where the generation of desired ion species is maximized through molecular gas discharge, the intrinsic characteristics of the instability dependent on the ion mass inevitably require consideration of the coexistence of various ion species. In this work, we experimentally studied the spoke in the E B Penning source with two-ion-species plasma. By adjusting the mixture ratio of argon and krypton gases, we investigated the changes in instability frequency with electrical diagnostics. Two frequency peaks were clearly observed, with the peaks of lower and higher frequencies corresponding to mode numbers 2 and 3, respectively. The frequencies of each peak shifted to higher values when the argon content in the gas mixture was increased. Finally, the theoretical scaling of the spoke suggests that the changes in the frequencies are proportional to the inverse square root of the effective ion mass.

Influence of the argon ratio on the structure and properties of thin films prepared using PECVD in TMSAc/Ar mixtures

Capacitively coupled RF glow discharge was used to form novel coatings of SiOxCyHz using varying proportions of trimethylsilyl acetate (TMSAc) monomer and the carrier gas argon. The properties of the TMSAc-based plasma polymers produced depend significantly on the proportion of argon in TMSAc/Ar gaseous mixture, which ranged from 0 % to 75 %. Reaction mixtures containing less than 50 % Ar produced hydrophobic polymers, for which the indentation hardness values were less than 1.5 GPa. Seventy-five percent argon in the reaction mixture yielded a crosslinked carbon-rich organosilicon structure with a hardness of 6 GPa. As many applications require good stability in a liquid environment, the TMSAc-based coatings were immersed in phosphate buffered saline (PBS) for 14 days. Because any material used in a medical application must be resistant to the techniques used for sterilization, the prepared coatings were subjected to a standard sterilization procedure using UVC radiation. A degree of the structural changes induced by both environments corresponded to the argon ratio used for production of thin films. Possible degradation mechanisms were examined and discussed. Using 7.7–21.4 % Ar during the deposition process led to the TMSAc-based plasma polymers exhibiting good resistance to the prolonged immersion in PBS and UVC sterilization.

Ultralow Macroscale Friction and Wear of MoS2 in High‐Vacuum Through DC Pulsing Optimization, Nitridization, and Sublayer Engineering

AbstractThe reliability and durability of devices that operate in vacuum and are subjected to wear are critical issues. The concerns rise at the macroscale wherein the contact area is large, yet the contact stress is in the GPa range. This paper reports on the design and fabrication of a coating comprising nitridized molybdenum disulfide (MoSN) supported by a novel nanolayered coating composed of carbon with subnanometer‐thick periodic albeit discrete Cr interlayers. The MoSN coatings are deposited onto mating surfaces using pulsed‐DC magnetron sputtering in an atmosphere with varying N2 to argon (Ar) ratios. Pulsed‐DC parameters, such as pulse duty and frequency, together with nitrogen content, are systematically optimized to achieve superior mechanical and tribological properties. The results reveal the importance of optimizing pulsing parameters during deposition as they significantly alter the properties of MoS2. The outcome is fabrication of a coating that despite having a low thickness, exhibits extremely low friction and record‐breaking macroscale wear rate in high vacuum compared to the values reported in the literature by date. Lastly, the analysis confirms the prediction of theoretical studies regarding the release of entrapped nitrogen in gaseous form during the wear process without disrupting the formation of a stable solid lubricant tribofilm.

Methods and benefits of measuring non-hydrocarbon gases from surface casing vents

Surface casing vents divert natural gas migration along oil and gas boreholes to bypass groundwater, with the gas venting to the atmosphere. While this strategy is designed to protect groundwater, it constitutes a source of greenhouse gases to the atmosphere. In instances where gas leakage occurs, the characterization of the molecular and isotopic composition of natural gas emitted from surface casing vent flows can be used to assist in identifying the gas source. We compare concentration measurements of non-hydrocarbon gases (within natural gas) of samples analyzed by laboratory-based gas chromatography (N2, Ar, CO2 and O2) and magnetic sector noble gas mass spectrometry (He, Ar and Kr) with field measurements conducted using a field portable quadrupole mass spectrometer (miniRUEDI). The standard deviation of miniRUEDI concentration results was within plus/minus one standard deviation of samples measured using laboratory-based GC (N2, O2, Ar and He) and magnetic sector noble gas mass spectrometry (He, Ar). Additional laboratory-based determination of isotope ratios of methane and argon (δ13CCH4, δ2HCH4, and 40Ar/36Ar) enabled a comparison between information provided by the analysis of reactive gases compared with noble gas isotopes. Gases from different sources displayed quantifiable differences in δ13CCH4 and δ2HCH4, but these changes may or may not be distinguished if only one sampling event is conducted. By comparison, 40Ar/36Ar further enabled the differentiation of various gas sources. The objective of this paper is to discuss the advantages and trade-offs of the three different analysis methods considered, and the feasibility of their application in different environmental monitoring scenarios.

The Influence of the Vietnam Offshore Current and Kuroshio Intrusion on Net Community Production in the Oligotrophic South China Sea in Summer

AbstractIn summer, the Vietnam Offshore Current (VOC) and the Kuroshio intrusion are two important processes inducing considerable environmental fluctuations in the surface water of the South China Sea (SCS). Net community production (NCP) is an important proxy of the biological pump strength and can be estimated based on the dissolved oxygen to argon ratio (O2/Ar) in the mixed layer. To quantify the influence of the VOC and Kuroshio intrusion on NCP in the oligotrophic SCS, we obtained continuous measurements of O2/Ar in the upper mixed layer using membrane inlet mass spectrometry (MIMS) in the northeastern SCS in summer 2017. Average NCP was 2.6 ± 1.5 mmol C m−2 d−1 in Phase 1 (from 13 to 20 July), 5.3 ± 1.7 mmol C m−2 d−1 in Phase 2 (from 20 to 25 July), and 13.9 ± 2.3 mmol C m−2 d−1 in Phase 3 (from 30 July to 9 August). Data from the region influenced by vertical mixing were excluded. A strong correlation between the surface dissolved inorganic nitrogen (DIN) and NCP was obtained, indicating that DIN was an essential factor controlling NCP in the SCS surface water. During our sampling, the Kuroshio intruded into the northeastern SCS in a loop pattern through the Luzon Strait, approximately halving the surface DIN concentration and reducing NCP by 36%. In addition, the VOC drove Vietnam coastal upwelled water to extend northeastward, causing an increase of 140% in the surface DIN concentration and an associated elevation of 160% in NCP in the northeastern SCS.

New constraints on biological production and mixing processes in the South China Sea from triple isotope composition of dissolved oxygen

Abstract. The South China Sea (SCS) is the world's largest marginal sea, playing an important role in the regional biogeochemical cycling of carbon and oxygen. However, its overall metabolic balance, primary production rates and links to East Asian Monsoon forcing remain poorly constrained. Here, we report seasonal variations in triple oxygen isotope composition (17Δ) of dissolved O2, a tracer for biological O2, gross primary production (GP; inferred from δ17O and δ18O values) and net community production (NP; evaluated from oxygen–argon ratios) from the SouthEast Asian Time-series Study (SEATS) in the SCS. Our results suggest rather stable mixed-layer mean GP rates of ∼ 1500 ± 350 mg C m−2 d−1 and mean NP of ∼ −13 ± 20 mg C m−2 d−1 during the summer southwest monsoon season. These values indicate, within uncertainties and variabilities observed, that the metabolism of the system was in net balance. During months influenced by the stronger northeast monsoon forcing, the system appears to be more dynamic and with variable production rates, which may shift the metabolism to net autotrophy (with NP rates up to ∼ 140 mg C m−2 d−1). Furthermore, our data from the deeper regions show that the SCS circulation is strongly affected by monsoon wind forcing, with a larger part of the water column down to at least 400 m depth fully exchanged during a winter, suggesting the 17Δ of deep O2 as a valuable novel tracer for probing mixing processes. Altogether, our findings underscore the importance of monsoon intensity on shifting the carbon balance in this warm oligotrophic sea and on driving the regional circulation pattern.

Composition control and selective infrared radiative properties of copper alloy oxides by DC reactive sputtering

In order to identify new selective infrared radiative materials, Cu80Ni15Ag5 and Cu70Ni25Ag5 oxides were prepared by DC reactive magnetron sputtering under atmosphere with different ratio of argon to oxygen. The composition of the copper alloy oxides was analyzed by XRD, XPS and Raman. When the ratio of argon to oxygen was 50:2, the alloy oxide is amorphous, whereas the alloy oxide prepared at the ratio of argon to oxygen from 50:4 to 50:10 is Cu4O3. The doping of Ni and Ag may impede CuO phase formation, deteriorate the crystallinity, and increase the defects. The emissivity measurement results show that Cu70Ni25Ag5 oxides prepared at the ratio of argon to oxygen of 50:10 have good selective infrared radiative properties, and the emissivity difference is more than 0.8 between 3μm band and 8-14μm band.

Controlled deposition of plasma‐polyaniline thin film by PECVD: Understanding the influence of aniline to argon ratio

AbstractLow pressure capacitively coupled radiofrequency plasmas operated in a mixture of aniline vapor and argon are used for the deposition of thin films on silicon substrates. The influence of the aniline vapor fraction in the gas mixture upon the plasma properties and the characteristics of the deposited thin film is analyzed. Plasmas diagnostics are carried out using mass spectrometry and optical emission spectroscopy and the thin films are characterized by means of Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, and near‐edge X‐ray absorption fine‐structure spectroscopy. Experiments highlight that the use of a low aniline/argon ratio leads to the deposition of an amorphous film whereas high‐aniline/argon ratios allow the synthesis of a plasma polymer similar to polyaniline. The properties of such plasmas and the mechanisms involved in the deposition process are discussed in detail.