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Improvement in growth yield of single-walled carbon nanotubes with narrow chirality distribution by pulseplasma CVD

Bin Xu, Toshiro Kaneko, Toshiaki Kato

《化学科学与工程前沿(英文)》 2019年 第13卷 第3期   页码 485-492 doi: 10.1007/s11705-019-1831-2

摘要: A pulse plasma chemical vapor deposition (CVD) technique was developed for improving the growth yield of single-walled carbon nanotubes (SWNTs) with a narrow chirality distribution. The growth yield of the SWNTs could be improved by repetitive short duration pulse plasma CVD, while maintaining the initial narrow chirality distribution. Detailed growth dynamics is discussed based on a systematic investigation by changing the pulse parameters. The growth of SWNTs with a narrow chirality distribution could be controlled by the difference in the nucleation time required using catalysts comprising relatively small or large particles as the key factor. The nucleation can be controlled by adjusting the pulse on/off time ratio and the total processing time.

关键词: single-walled carbon nanotubes     chirality-controlled synthesis     pulse plasma chemical vapor deposition    

The role of ions in plasma catalytic carbon nanotube growth: A review

Erik C. Neyts

《化学科学与工程前沿(英文)》 2015年 第9卷 第2期   页码 154-162 doi: 10.1007/s11705-015-1515-5

摘要: While it is well-known that the plasma-enhanced catalytic chemical vapor deposition (PECVD) of carbon nanotubes (CNTs) offers a number of advantages over thermal CVD, the influence of the various individual contributing factors is not well understood. Especially the role of ions is unclear, since ions in plasmas are generally associated with sputtering rather than with growing a material. Even so, various studies have demonstrated the beneficial effects of ion bombardment during the growth of CNTs. This review looks at the role of the ions in plasma-enhanced CNT growth as deduced from both experimental and simulation studies. Specific attention is paid to the beneficial effects of ion bombardment. Based on the available literature, it can be concluded that ions can be either beneficial or detrimental for carbon nanotube growth, depending on the exact conditions and the control over the growth process.

关键词: plasma-enhanced chemical vapor deposition (PECVD)     carbon nanotube (CNT)     ion bombardment     defect healing    

Preparation of TiO

Shenghung WANG, Kuohua WANG, Jihmirn JEHNG, Lichen LIU

《环境科学与工程前沿(英文)》 2012年 第6卷 第3期   页码 304-312 doi: 10.1007/s11783-010-0297-8

摘要: Titanium dioxide is coated on the surface of MCM-41 wafer through the plasma enhanced chemical vapor deposition (PECVD) method using titanium isopropoxide (TTIP) as a precursor. Annealing temperature is a key factor affecting crystal phase of titanium dioxide. It will transform an amorphous structure to a polycrystalline structure by increasing temperature. The optimum anatase phase of TiO which can acquire the best methanol conversion under UV-light irradiation is obtained under an annealing temperature of 700°C for 2 h, substrate temperature of 500°C, 70 mL·min of oxygen flow rate, and 100 W of plasma power. In addition, the films are composed of an anatase-rutile mixed phase, and the ratio of anatase to rutile varies with substrate temperature and oxygen flow rate. The particle sizes of titanium dioxide are between 30.3 nm and 59.9 nm by the calculation of Scherrer equation. Under the reaction conditions of 116.8 mg·L methanol, 2.9 mg·L moisture, and 75°C of reaction temperature, the best conversion of methanol with UV-light is 48.2% by using the anatase-rutile (91.3/8.7) mixed phase TiO in a batch reactor for 60 min. While under fluorescent light irradiation, the best photoactivity appears by using the anatase-rutile (55.4/44.6) mixed phase TiO with a conversion of 40.0%.

关键词: photocatalyst     titanium dioxide     MCM-41     plasma enhanced chemical vapor deposition (PECVD)    

manufacturing of carbon nanotubes in a continuous inclined mobile-bed rotating reactor via the catalytic chemicalvapor deposition process

Sophie L. Pirard, Sigrid Douven, Jean-Paul Pirard

《化学科学与工程前沿(英文)》 2017年 第11卷 第2期   页码 280-289 doi: 10.1007/s11705-017-1635-1

摘要: This article reports the different steps of the design, development and validation of a process for continuous production of carbon nanotubes (CNTs) via catalytic chemical vapor deposition from the laboratory scale to the industrial production. This process is based on a continuous inclined mobile-bed rotating reactor and very active catalysts using methane or ethylene as carbon source. The importance of modeling taking into account the hydrodynamic, physicochemical and physical phenomena that occur during CNT production in the process analysis is emphasized. The impact of this invention on the environment and human health is taken into consideration too.

关键词: carbon nanotubes     catalytic chemical vapor deposition     inclined rotating reactor     industrial process     scaling-up    

Plasma enhanced chemical vapor deposition of excellent a-Si:H passivation layers for a-Si:H/c-Si heterojunction

Lei ZHAO,Wenbin ZHANG,Jingwei CHEN,Hongwei DIAO,Qi WANG,Wenjing WANG

《能源前沿(英文)》 2017年 第11卷 第1期   页码 85-91 doi: 10.1007/s11708-016-0437-3

摘要: The intrinsic a-Si:H passivation layer inserted between the doped a-Si:H layer and the c-Si substrate is very crucial for improving the performance of the a-Si:H/c-Si heterojunction (SHJ) solar cell. The passivation performance of the a-Si:H layer is strongly dependent on its microstructure. Usually, the compact a-Si:H deposited near the transition from the amorphous phase to the nanocrystalline phase by plasma enhanced chemical vapor deposition (PECVD) can provide excellent passivation. However, at the low deposition pressure and low deposition power, such an a-Si:H layer can be only prepared in a narrow region. The deposition condition must be controlled very carefully. In this paper, intrinsic a-Si:H layers were prepared on n-type Cz c-Si substrates by 27.12 MHz PECVD at a high deposition pressure and high deposition power. The corresponding passivation performance on c-Si was investigated by minority carrier lifetime measurement. It was found that an excellent a-Si:H passivation layer could be obtained in a very wide deposition pressure and power region. Such wide process window would be very beneficial for improving the uniformity and the yield for the solar cell fabrication. The a-Si:H layer microstructure was further investigated by Raman and Fourier transform infrared (FTIR) spectroscopy characterization. The correlation between the microstructure and the passivation performance was revealed. According to the above findings, the a-Si:H passivation performance was optimized more elaborately. Finally, a large-area SHJ solar cell with an efficiency of 22.25% was fabricated on the commercial 156 mm pseudo-square n-type Cz c-Si substrate with the open-circuit voltage ( ) of up to 0.732 V.

关键词: PECVD     high pressure and high power     a-Si:H microstructure     passivation     heterojunction solar cell    

无溶剂气相制备用于可持续分离过程的膜材料 Perspective

赵俊杰, Karen K. Gleason

《工程(英文)》 2020年 第6卷 第12期   页码 1432-1442 doi: 10.1016/j.eng.2020.05.002

摘要:

可用于水净化、碳捕集、生物燃料生产、燃料电池运行以及节能工业分离操作的可持续化工过程亟待发展下一代膜材料。膜的无溶剂制备不仅消除了有机溶剂的潜在环境问题,而且解决了脆弱聚合物基材的膨胀问题。此外,采用无溶剂气相沉积方法可以减少合成微孔材料[如金属有机骨架(MOF)]所需的活化步骤。本文综述了几种真空沉积工艺,包括引发式化学气相沉积(iCVD)、引发式等离子体增强化学气相沉积(iPECVD)、无溶剂气相沉积原位聚合(SLIP)、原子层沉积(ALD) 和分子层沉积(MLD)。这些无溶剂气相沉积方法在制备薄膜复合膜结构中的超薄选择层方面极具优势,而且能够保形地修饰纳米级孔道并精确调节孔径和孔内官能团。所制备的膜在气体分离、 纳滤、海水淡化和水/油分离等方面表现出颇具应用潜力的性能。因此,开发新型膜材料、放大可用于无溶剂气相沉积的高通量反应器将对化学工业产生巨大影响。

关键词: 膜分离     化学气相沉积     原子层沉积     分子层沉积     薄膜     金属有机骨架     聚合物     先进制造    

Phosphorene: Current status, challenges and opportunities

Anandarup Goswami, Manoj B. Gawande

《化学科学与工程前沿(英文)》 2019年 第13卷 第2期   页码 296-309 doi: 10.1007/s11705-018-1783-y

摘要: The field of 2-dimensional (2D) materials has witnessed a sharp growth since its inception and can majorly be attributed to the substantial technical and scientific developments, leading to significant improvements in their syntheses, characterization and applications. In the list of 2D materials, the relatively newer addition is phosphorene, which ideally consists of a single layer of black phosphorous. Keeping in mind the past, and ongoing research activities, this short account offers a brief overview of the present status and the associated challenges in the field of phosphorene-related research, with special emphasis on their syntheses, properties, applications and future opportunities.

关键词: phosphorene     black phosphorous     anisotropy     single layer     thermoelectric     chemical vapor deposition     catalysis     battery     supercapacitor    

Ultrafast solid-liquid-vapor phase change of a thin gold film irradiated by femtosecond laser pulsesand pulse trains

Jing HUANG, Yuwen ZHANG, J. K. CHEN, Mo YANG

《能源前沿(英文)》 2012年 第6卷 第1期   页码 1-11 doi: 10.1007/s11708-012-0179-9

摘要: Effects of different parameters on the melting, vaporization and resolidification processes of thin gold film irradiated by femtosecond pulses and pulse train were systematically studied. The classical two-temperature model was adopted to depict the non-equilibrium heat transfer in electrons and lattice. The melting and resolidification processes, which was characterized by the solid-liquid interfacial velocity, as well as elevated melting temperature and depressed solidification temperature, was obtained by considering the interfacial energy balance and nucleation dynamics. Vaporization process which leads to ablation was described by tracking the location of liquid-vapor interface with an iterative procedure based on energy balance and gas kinetics law. The parameters in discussion included film thickness, laser fluence, pulse duration, pulse number, repetition rate, pulse train number, etc. Their effects on the maximum lattice temperature, melting depth and ablation depth were discussed based on the simulation results.

关键词: melting     evaporation     nucleation dynamics     nanoscale heat transfer    

Direct synthesis of carbon nanotubes on fly ash particles to produce carbon nanotubes/fly ash composites

Fangxian LI, Cheng ZHOU, Pengfei YANG, Beihan WANG, Jie HU, Jiangxiong WEI, Qijun YU

《结构与土木工程前沿(英文)》 2019年 第13卷 第6期   页码 1405-1414 doi: 10.1007/s11709-019-0564-0

摘要: Fly ash was used as catalytic support for carbon nanotubes (CNTs) growth by chemical vapor deposition (CVD) due to having ideal compositions (SiO , Al O , and Fe O ). In this paper, CNTs were synthesized on Ni catalyst/fly ash substrate using CVD method. The influence of parameters (e.g., reaction temperature and gas flow rate) on the carbon yield and structure of the resulting CNTs was on the carbon yield and structure of the resulting CNTs was investigated by thermo-gravimetric analyses, Scanning electron microscopy, and Raman spectroscopy analysis. The results indicated that the growth temperature controlling had a significant effect on the diameter of CNTs. And the proper acetylene and hydrogen flow rate would decrease in defect density and increase in yield of as-grown CNTs on fly ash. Finally, the amorphous carbon on the surface of as-grown CNTs were removed by heating in air. Experimental results showed that the hydrophobic of the annealed CNTs was weak due to introducing functional groups to the surface of CNTs.

关键词: carbon nanotubes     fly ash     chemical vapor deposition     parameters     purification    

Where physics meets chemistry: Thin film deposition from reactive plasmas

Andrew Michelmore, Jason D. Whittle, James W. Bradley, Robert D. Short

《化学科学与工程前沿(英文)》 2016年 第10卷 第4期   页码 441-458 doi: 10.1007/s11705-016-1598-7

摘要: Functionalising surfaces using polymeric thin films is an industrially important field. One technique for achieving nanoscale, controlled surface functionalization is plasma deposition. Plasma deposition has advantages over other surface engineering processes, including that it is solvent free, substrate and geometry independent, and the surface properties of the film can be designed by judicious choice of precursor and plasma conditions. Despite the utility of this method, the mechanisms of plasma polymer growth are generally unknown, and are usually described by chemical (i.e., radical) pathways. In this review, we aim to show that plasma physics drives the chemistry of the plasma phase, and surface-plasma interactions. For example, we show that ionic species can react in the plasma to form larger ions, and also arrive at surfaces with energies greater than 1000 kJ?mol (>10 eV) and thus facilitate surface reactions that have not been taken into account previously. Thus, improving thin film deposition processes requires an understanding of both physical and chemical processes in plasma.

关键词: thin films     plasma physics     plasma chemistry     functionalization     polymer    

Growth and properties analysis of metal-organic chemical vapor deposited MgZnO films on -AlO substrates

SHI Zengliang, LIU Dali, YAN Xiaolong, GAO Zhongmin, BAI Shiying

《机械工程前沿(英文)》 2008年 第3卷 第3期   页码 261-264 doi: 10.1007/s11465-008-0036-z

摘要: MgZnO (0 < ? 0.12) thin films with the wurtzite structure have been successfully grown on -AlO substrates by metal-organic chemical vapor deposition (MOCVD). X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), photoluminescence (PL) spectrometry, and transmission measurements are performed to study the characteristics of MgZnO thin films. Results show that with increasing Mg content, the diffraction peak of MgZnO thin films shifts towards a higher diffraction angle (the biggest shift is 0.22°), and the full width at half maximum (FWHM) of the diffraction peak is broadened. Meanwhile, a blue-shift occurs at the near-band-edge (NBE) emission peak and the largest blue-shift of the band gap of the MgZnO films is 113 meV with Mg content = 0.12. Therefore, the energy band gap of the MgZnO films is determined by Mg content in the thin films and the energy band gap increases with an increase of Mg content.

关键词: increase     photoelectron spectroscopy     transmission     wurtzite structure     MgZnO    

Multifunctional antimicrobial chlorhexidine polymers by remote plasma assisted vacuum deposition

Ana Mora-Boza, Francisco J. Aparicio, María Alcaire, Carmen López-Santos, Juan P. Espinós, Daniel Torres-Lagares, Ana Borrás, Angel Barranco

《化学科学与工程前沿(英文)》 2019年 第13卷 第2期   页码 330-339 doi: 10.1007/s11705-019-1803-6

摘要: Novel antibacterial materials for implants and medical instruments are essential to develop practical strategies to stop the spread of healthcare associated infections. This study presents the synthesis of multifunctional antibacterial nanocoatings on polydimethylsiloxane (PDMS) by remote plasma assisted deposition of sublimated chlorhexidine powders at low pressure and room temperature. The obtained materials present effective antibacterial activity against K12, either by contact killing and antibacterial adhesion or by biocide agents release depending on the synthetic parameters. In addition, these multifunctional coatings allow the endure hydrophilization of the hydrophobic PDMS surface, thereby improving their biocompatibility. Importantly, cell-viability tests conducted on these materials also prove their non-cytotoxicity, opening a way for the integration of this type of functional plasma films in biomedical devices.

关键词: plasma polymers     conformal plasma deposition     chlorhexidine     bactericide     PDMS     biocompatibility    

Development of new transient liquid phase system Au-Sn-Au for microsystem technology

Kirsten BOBZIN, Nazlim BAGCIVAN, Lidong ZHAO, Stefania FERRARA, Jan PERNE

《机械工程前沿(英文)》 2010年 第5卷 第4期   页码 370-375 doi: 10.1007/s11465-010-0107-9

摘要: In the last decade, microsystems evolved to decisive technology in many technical applications. With increasing requirements on the performance of microsystems, more and more dissimilar materials are used in the same assembly. Correspondingly, suitable joining methods are required to fulfil the requirements on good properties of joints. In this study, a new transient liquid phase (TLP) system Au-Sn-Au was developed for potential medical applications in hybrid microsystems. The high and low melting phases Au and Sn were deposited onto diverse substrates by magnetron-sputter-ion plating. The coated substrates were soldered in a microsoldering station under different conditions. The influence of soldering conditions on the microstructure and properties of the joints was investigated. Results show that the developed solder led to high-quality joints that can be used in microsystems for medical applications.

关键词: transient liquid phase     microtechnology     soldering     diffusion     physical vapor deposition (PVD)    

Esophageal pulse oximetry is more accurate and detects hypoxemia earlier than conventional pulse oximetry

null

《医学前沿(英文)》 2012年 第6卷 第4期   页码 406-410 doi: 10.1007/s11684-012-0217-3

摘要:

The esophagus is perfused directly by prominent arteries and may provide a more consistent tissue source for pulse oximetry. The goal of this study was to evaluate the sensitivity and accuracy of an esophageal pulse oximetry probe on patients during controlled hypoxemia in comparison to measurements obtained with conventional pulse oximetry (SpulseO2). Forty-five ASA I–II adult patients were included in this prospective observational study. Nellcor digital oximetric probes were placed on finger tips for SpulseO2 before anesthesia. After tracheal intubation, an esophageal probe was placed in the lower segment of the esophagus for esophageal oximetric monitoring (SoesO2). All patients were disconnected from the breathing circuit to establish a controlled hypoxemia, and were re-connected to the breathing circuit and ventilated with 100% oxygen immediately when SoesO2 dropped to 90%. Matched SoesO2 and SpulseO2 readings were recorded when SoesO2measurements were at 100%, 95%, 90% and the lowest reading. The time for SoesO2 and SpulseO2 to drop from 100% to 95%, 90% and return to 100% was recorded. Oxygen saturation from arterial blood samples (SartO2) was also measured at each time point respectively. The linear correlation coefficient of the regression analysis between SartO2 and SoesO2 was 0.954. The mean±2SD of the difference was 0.3%±4.3% for SoesO2vs. SartO2 and 6.8%±5.6% for SpulseO2vs. SartO2 (P<0.001). The 95% confidence interval for the absolute difference between SoesO2 and SartO2 was 0.3% to 0.7% and 6.2% to 7.4% between SpulseO2 and SartO2. The time to reach 90% saturation measured with SoesO2 was approximately 94 seconds earlier than the SpulseO2 (P<0.001). In conclusion, SoesO2 is more accurate and enables earlier detection of hypoxemia when compared to conventional pulse oximetry during hypoxemia for patients undergoing general anesthesia.

关键词: esophageal pulse oximetry     conventional pulse oximetry     hypoxemia    

Heat transfer characteristics of high heat flux vapor chamber

Dongchuan MO, Shushen LU, Haoliang ZHENG, Chite CHIN,

《能源前沿(英文)》 2010年 第4卷 第2期   页码 166-170 doi: 10.1007/s11708-009-0076-z

摘要: To meet the challenge of heat spreading in electronic products, highly efficient high heat flux heat transfer vapor chambers have been manufactured and their heat transfer characteristics have been studied by a fast test system. A solid copper block with the same shape as the vapor chamber is used to compare the performance of the vapor chamber. The result shows that, it will take about 5min to achieve a steady state in the fast test system. The heat transfer characteristics of the vapor chamber are more superior to those of the copper block. In this paper, total thermal resistance of the test system is used to evaluate the heat transfer characteristics of the vapor chamber, because it has already been used to consider both the spreading thermal resistance and the flatness of the vapor chamber.

关键词: high heat flux     vapor chamber (VC)     heat transfer characteristics     fast test    

标题 作者 时间 类型 操作

Improvement in growth yield of single-walled carbon nanotubes with narrow chirality distribution by pulseplasma CVD

Bin Xu, Toshiro Kaneko, Toshiaki Kato

期刊论文

The role of ions in plasma catalytic carbon nanotube growth: A review

Erik C. Neyts

期刊论文

Preparation of TiO

Shenghung WANG, Kuohua WANG, Jihmirn JEHNG, Lichen LIU

期刊论文

manufacturing of carbon nanotubes in a continuous inclined mobile-bed rotating reactor via the catalytic chemicalvapor deposition process

Sophie L. Pirard, Sigrid Douven, Jean-Paul Pirard

期刊论文

Plasma enhanced chemical vapor deposition of excellent a-Si:H passivation layers for a-Si:H/c-Si heterojunction

Lei ZHAO,Wenbin ZHANG,Jingwei CHEN,Hongwei DIAO,Qi WANG,Wenjing WANG

期刊论文

无溶剂气相制备用于可持续分离过程的膜材料

赵俊杰, Karen K. Gleason

期刊论文

Phosphorene: Current status, challenges and opportunities

Anandarup Goswami, Manoj B. Gawande

期刊论文

Ultrafast solid-liquid-vapor phase change of a thin gold film irradiated by femtosecond laser pulsesand pulse trains

Jing HUANG, Yuwen ZHANG, J. K. CHEN, Mo YANG

期刊论文

Direct synthesis of carbon nanotubes on fly ash particles to produce carbon nanotubes/fly ash composites

Fangxian LI, Cheng ZHOU, Pengfei YANG, Beihan WANG, Jie HU, Jiangxiong WEI, Qijun YU

期刊论文

Where physics meets chemistry: Thin film deposition from reactive plasmas

Andrew Michelmore, Jason D. Whittle, James W. Bradley, Robert D. Short

期刊论文

Growth and properties analysis of metal-organic chemical vapor deposited MgZnO films on -AlO substrates

SHI Zengliang, LIU Dali, YAN Xiaolong, GAO Zhongmin, BAI Shiying

期刊论文

Multifunctional antimicrobial chlorhexidine polymers by remote plasma assisted vacuum deposition

Ana Mora-Boza, Francisco J. Aparicio, María Alcaire, Carmen López-Santos, Juan P. Espinós, Daniel Torres-Lagares, Ana Borrás, Angel Barranco

期刊论文

Development of new transient liquid phase system Au-Sn-Au for microsystem technology

Kirsten BOBZIN, Nazlim BAGCIVAN, Lidong ZHAO, Stefania FERRARA, Jan PERNE

期刊论文

Esophageal pulse oximetry is more accurate and detects hypoxemia earlier than conventional pulse oximetry

null

期刊论文

Heat transfer characteristics of high heat flux vapor chamber

Dongchuan MO, Shushen LU, Haoliang ZHENG, Chite CHIN,

期刊论文