Direct Synthesis of Layer-Tunable and Transfer-Free Graphene on Device-Compatible Substrates Using Ion Implantation Toward Versatile Applications

Direct synthesis of layer-tunable and transfer-free graphene on technologically important substrates is highly valued for various electronics and device applications.State of the art in the field is currently a two-step process:a high-quality graphene layer synthesis on metal substrate through chemical vapor deposition(CVD)followed by delicate layer transfer onto device-relevant substrates.Here,we report a novel synthesis approach combining ion implantation for a precise graphene layer control and dual-metal smart Janus substrate for a diffusion-limiting graphene formation to directly synthesize large area,high quality,and layer-tunable graphene films on arbitrary substrates without the post-synthesis layer transfer process.Carbon(C)ion implantation was performed on Cu-Ni film deposited on a variety of device-relevant substrates.A well-controlled number of layers of graphene,primarily monolayer and bilayer,is precisely controlled by the equivalent fluence of the implanted C-atoms(1 monolayer~4×10^(15)C-atoms/cm^(2)).Upon thermal annealing to promote Cu-Ni alloying,the pre-implanted C-atoms in the Ni layer are pushed toward the Ni/substrate interface by the top Cu layer due to the poor C-solubility in Cu.As a result,the expelled C-atoms precipitate into a graphene structure at the interface facilitated by the Cu-like alloy catalysis.After removing the alloyed Cu-like surface layer,the layer-tunable graphene on the desired substrate is directly realized.The layer-selectivity,high quality,and uniformity of the graphene films are not only confirmed with detailed characterizations using a suite of surface analysis techniques but more importantly are successfully demonstrated by the excellent properties and performance of several devices directly fabricated from these graphene films.Molecular dynamics(MD)simulations using the reactive force field(ReaxFF)were performed to elucidate the graphene formation mechanisms in this novel synthesis approach.With the wide use of ion implantation technology in the microelectronics industry,this novel graphene synthesis approach with precise layer-tunability and transfer-free processing has the promise to advance efficient graphene-device manufacturing and expedite their versatile applications in many fields.

Hydrogenation of zirconium film by implantation of hydrogen ions

In order to understand the dnve-in target in a D-D type neutron generator,it is essential to study the mechanism of the interaction between hydrogen ion beams and the hydrogenabsorbing metal film.The present research concerns the nucleation of hydride within zirconium film implanted with hydrogen ions.Doses of 30 keV hydrogen ions ranging from 4.30×10^（17） to1.43×10^（18） ions cm^（-2） were loaded into the zirconium film through the ion beam implantation technique.Features of the surface morphology and transformation of phase structures were investigated with scanning electron microscopy,atomic force microscopy and x-ray diffraction.Confirmation of the formation of 5 phase zirconium hydride in the implanted samples was first made by x-ray diffraction,and the different stages in the gradual nucleation and growth of zirconium hydride were then observed by atomic force microscope and scanning electron microscopy.

Formation of Nanoscale Intermetallic Phases in Ni Surface Layer at High Intensity Implantation of Al Ions

The results of experimental study of nanoscale intermetallic formation in surface layer of a metal target at ion implantation are presented. To increase the thickness of the ion implanted surface layer the high intensive ion implantation is used. Compared with the ordinary ion implantation, the high intensive ion implantation allows a much thicker modified surface layer. Pure polycrystalline nickel was chosen as a target. Nickel samples were irradiated with Al ions on the vacuum-arc ion beam and plasma flow source 'Raduga-5'. It was shown that at the high intensity ion implantation the fine dispersed particles of Ni3AI, NiAl intermetallic compounds and solid solution Al in Ni are formed in the nickel surface layer of 200 nm and thicker. The formation of phases takes place in complete correspondence with the Ni-AI phase diagram.

After cochlear implantation: Complications related to flap around implants

Objective: To report complications related to flap around implants after cochlear implantation, possible causes of such complications and treatments. Methods and material:We performed a retrospective analysis of children in whom complications related to flap around implants occurred after undergoing cochlear implantation in our department from 2005 to 2016. Results:Complications among 1500 cochlear implantation (CI) recipients by the same surgeon included hematoma (n ? 20) and seroma around implants (n ? 15), of which most (n ? 10) recovered in 2 weeks after effective drainage, utility of antibiotics and pressure dressing, but 5 developed flap necrosis and had to undergo contralateral re-implantation. Four patients developed abscess around implants, of whom 2 recovered after 2 weeks of drainage, gentamicin irrigation and use of antibiotics, but 2 patients ended up with flap necrosis and had to receive contralateral reimplantation. Conclusions: Immediate drainage, pressure dressing and antibiotics can be used to effectively control seroma around implants. For seroma lasting for more than two weeks without improvement, surgical drainage may be need.

Serial observations on an orthotopic gastric cancer model constructed using improved implantation technique

AIM:To establish a gastric cancer nude-mouse model with improved orthotopic implantation and investigate its biological characteristics at different time points.METHODS:Human gastric cancer SGC-7901 cell suspensions were injected subcutaneously into a nude mouse to develop solid tumors,and the tumor tissue pieces were implanted under the serous coat.The nude mice were then euthanized in group every two weeks to observe the primary tumor growth and metastases.RESULTS:Within 2-4 wk,there were no obvious chang-es about the primary tumor in stomach.At the sixth week,the primary tumor began to grow fast,resulting in incrassation of the gastric wall and stenosis of the gastric cavity,and metastases into the liver and lymph nodes were detected.The tumor,which compressed the adjacent organs,gradually became bigger and bigger followed by stenosis or vanishment of the gastric cavity from 8 to 12 wk.There were massive metastases,and the rate of metastasis was 58%in lymph nodes,78%in liver,39%in kidney,and 81%in peritoneum or septum.CONCLUSION:A gastric cancer model is established,which can simulate the clinical tumor behavior and provide experimental carrier for clinical trials of gastric cancer treatment.

Clinical and prognostic implications of atrial fibrillation in patients undergoing transcatheter aortic valve implantation

AIM: To study a cohort of consecutive patients under-going transcatheter aortic valve implantation (TAVI) and compare the outcomes of atrial fibrillation (AF) patients vs patients in sinus rhythm (SR). METHODS: All consecutive patients undergoing TAVI in our hospital were included. The AF group comprised patients in AF at the time of TAVI or with history of AF, and were compared with the SR group. Procedural, echocardiographic and follow-up variables were compared. Likewise, the CHA 2 DS 2-VASC stroke risk score and HAS-BLED bleeding risk score and antithrombotic treatment at discharge in AF patients were compared with that in SR patients. RESULTS: From a total of 34 patients undergoing TAVI, 17 (50%) were allocated to the AF group, of whom 15 (88%) were under chronic oral anticoagulation. Patients in the AF group were similar to those in the SR group except for a trend (P = 0.07) for a higher logistic EuroSCORE (28% vs 19%), and a higher prevalence of hypertension (82% vs 53%) and chronic renal failure (17% vs 0%). Risk of both stroke and bleeding was high in the AF group (mean CHA 2 DS 2-VASC 4.3, mean HAS-BLED 2.9). In the AF group, treatment at discharge included chronic oral anticoagulation in all except one case, and in association with an antiplatelet drug in 57% of patients. During a mean follow-up of 11 mo (maximum 32), there were only two strokes, none of them during the peri-procedural period: one in the AF group at 30 mo and one in the SR group at 3 mo. There were no statistical differences in procedural success, and clinical outcome (survival at 1 year 81% vs 74% in AF and SR groups, respectively, P = NS). CONCLUSION: Patients in AF undergoing TAVI show a trend to a higher surgical risk. However, in our cohort, patients in AF did not have a higher stroke rate compared to the SR group, and the prognosis was similar in both groups.

Effects of Jiantaiye (健胎液) on Estrogen Receptor and mRNA Expressions in Uterus of Mice with Embryo Implantation Dysfunction

Objective: To explore the effect of Jiantaiye (健胎液, JTY) on the expression of estrogen receptor (ER) and ER mRNA in uterus of mice with embryo implantation dysfunction. Methods: Embryo implantation dysfunction mouse models were induced with mifepristone and treated with JTY. All animals were sacrificed on day 8 of pregnancy. The endometrial ER and ER mRNA expressions were assessed by immunnohistochemical SP method and semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR). Results: Area ratio and absorbency of ER in the JTY treated group's gland and stroma were higher than those of the model group, quite similar to those of the normal control's, and ER mRNA expression in treated group's uterus was significantly higher than that in the models, but it was not significantly different from the normal control. Conclusion: JTY improves the endometrial development by increasing ER and ER mRNA expressions of uterus of mice with embryo implantation dysfunction.

Comparative study of modified and conventional secondary hydroxyapatite orbital implantations

AIMTo compare the clinical effects of the modified and conventional secondary hydroxyapatite orbital implantations.

The effects of comprehensive nursing interventions on sexual functions in young and middle-aged patients with coronary stent implantation

Objective: To study the effects of comprehensive nursing interventions on sexual functions in young and middle-aged patients with coronary stent implantation. Methods: 96 cases of coronary stent implantation were randomly divided into control group and intervention group (experimental group) with each group of 48 cases. The control group received the routine nursing measures after the coronary stent implantation and the experimental group was treated by the comprehensive nursing interventions such as psychological nursing, education of sexual knowledge, playing the full enthusiasm of spouse and appropriate exercise therapy on basis of the routine nursing measures. The two groups were given the questionnaire of brief male sexual function questionnaire (BSFI), Chinese patients with premature ejaculation sexual function score (C-ISFPE) and the international index of erectile function (IIEF-5). The scores of BSFI, C-ISFPE and IIEF-5 were compared between the two groups. Results: There were 29 cases who were satisfied with sexual life on the whole (≤1), 26 cases with different degrees of premature ejaculation symptoms and 21 cases with erectile dysfunctions, which were respectively 27.08%, 30.2% and 21.87% of the total number. The scores of BSFI, C-ISFPE and IIEF-5 inthe experimental group were significantly increased after the interventions (P P IIEF-5 scores in the two groups were significantly different

The effects of implantable collamer lens implantation on higher order aberrations

AIM: To evaluate the changes in higher order aberrations(HOAs) after implantable collamer lens(ICL;Staar Surgical, Nidau, Switzerland) implantation. METHODS: Totally 30 eyes of 18 patients with myopia were included in this study with an average age of 25.77y(min: 21, max: 40). Refraction, uncorrected distance visual acuity(UDVA), corrected distance visual acuity(CDVA), HOAs(entire, corneal and internal) were evaluated preoperatively and three months postoperatively. Ocular aberrations were measured by using iT race(Tracey Technology, Houston, Texas, USA). SPSS(IBM Corp. Released 2013. IBM SPSS Statistics for Windows, Version 22.0. Armonk, NY: IBM Corp) was used for the statistical analysis and the interpretation of the data. P values of less than 0.05 were considered statistically significant. RESULTS: The preoperative mean spherical power was -9.01 D(min:-5.00, max:-13.00) and the mean cylindrical error was -2.40 D(min:-0.50, max:-4.75). The postoperative mean residual spherical power was -0.73 D(min:-0.20, max:-1.75) and the mean cylindrical error was -0.89 D(min:-0.18, max:-2.09). Analyses were made on root mean square(RMS) values of total HOAs(tH OAs), spherical aberration, coma and trefoil as entire, corneal and internal components. The differences in entire t HOAs and in internal t HOAs were significant. There was no significant change found in spherical aberrations. The differences in entire coma and in internal coma were significant. There was no significant change found in corneal coma. With respect to trefoil, the only significant difference was in internal trefoil. CONCLUSION: The ICL implantation corrects the refractive error successfully and changes entire and internal HOAs of the eye.

Clinical observations of iridociliary cysts and their changes after implantable collamer lens implantation in myopic patients

AIM:To observe the characteristics of iridociliary cysts in myopic patients and evaluate the influences on the position and safety of implantable collamer lens(ICL)after surgery.METHODS:Totally 270 eyes of 135 patients who underwent ICL surgery for the corrections of myopia were included in this study.Preoperative and postoperative morphology of iridociliary cysts were observed in ultrasonic biomicroscopy(UBM)image.RESULTS:A total of 138 iridociliary cysts were found in 88 eyes of 50 patients among 270 eyes of 135 patients before surgery(37%).Twenty-five patients had cysts in one eye(50%)and 25 had cysts in both eyes(50%).The prevalence of iridociliary cysts was negatively correlated with age,but no gender difference(P>0.05).The incidence of iridociliary cysts was much less in eyes with myopia greater than-9.00 D(P<0.05).The diameter of the largest cyst was 1.96 mm and the smallest cyst was 0.24 mm,with a majority within the range of 0.5 to 1.0 mm.Most of the cysts were located in the inferior temporal quadrant.One year after ICL implantation,51 iridociliary cysts(37%)remained unchanged,47 cysts(34%)decreased in size,and 40 cysts(29%)disappeared.Most of cysts that changed after surgery were smaller than 1.0 mm(P<0.05)and located in the nasal and temporal sides around the haptics of implantable lens.All the ICL were in their original position.CONCLUSION:Iridociliary cysts are commonly seen in myopic eyes.The cysts have no impact on the safety of ICL surgery.Some cysts may decrease in size or disappear after ICL implantation.

Investigations on ion implantation-induced strain in rotated Y-cut LiNbO_(3) and LiTaO_(3)

The monocrystalline LiNbO_(3)(LN)and LiTaO_(3)(LT)plates have been qualified as a kind of material platform for high performance RF filter that is considerable for the 5G communication.LN and LT thin films are usually transferred on handle wafers by combining ion-slicing and wafer bonding technique to form a piezoelectric on insulator(POI)substrate.The ion implantation is a key process and the implantation-induced strain is essential for the layer transfer.Here,we reported the strain profile of ion implanted rotated Y-cut LN and LT.The ion implantation generates the out-of-plane tensile strain of the sample surface and(006)plane,while both the tensile and compressive strain are observed on the(030)plane.The implanted ions redistributed due to the anisotropy of LN and LT,and induce the main tensile normal to the(006)plane.Meanwhile,the(030)planes are contracted due to the Poisson effect with the interstitial ions disturbing and mainly show a compressive strain profile.

XPS INVESTIGATION OF NITROGEN IONS IMPLANTED INTO ALUMINUM ALLOY BY PLASMA BASED ION IMPLANTATION

Aluminum alloy 2024 has been implanted with nitrogen ions at various doses by plasma based ion implantation. The introduction of energetic ions causes structural change within the near surface region of the solid. The samples have been characterized by X-ray Photoelectron Spectroscopy at various depths. The chemical states of Al and N were identified by deconvolution of the recorded XPS spectra. After plasma based ion implanted nitrogen into aluminum, not only the AlN precipitates but also super saturated solution of nitrogen forms. The presence of aluminum in different chemical states is corresponding to Al, AlN and Al2O3. The majority of nitrogen is in the form of the supersaturated solution. With the increase of nitrogen dose, the amount of AlN precipitates increases.

NH_2 Ion Implantations Induced Superior Cell Attachment of Carbon Nanotubes

Objective： Cell and platelet attachment on the multiwalled carbon nanotubes （MWCNTs） were studied by ion implantation. Methods： NH2 ion implantation was performed at the energy of 30 keV with the fluence of 1 x 1016 ions/era2 at room temperature. Results： The cell attachment tests showed interesting results in that the number of the platclets adhering on the surface of the MWCNTs was reduced significantly after NH2 ion implantation, whereas, mouse fibroblast cells （L929） cultured on NH2 ion implanted MWCNTs displayed higher cell-viability, proliferation, and stretching compared with MWCNTs. Conclusion： No appreciable change in the tensile strength and the optical transmittance of the implanted samples was observed. X-ray photoelectron spectroscopy （XPS） analysis showed that NH2 ion implantation caused the formation of new N-containing groups.

Preliminary Studies on Base Substitutions and Repair of DNA Mismatch Damage Stimulated by Low Energy N^+ Ion Beam Implantation in Escherichia coli

Ever since the low energy N+ ion beam has been accepted that the mutation effects of ionizing radiation are attributed mainly to direct or indirect damage to DNA. Evidences based on naked DNA irradiation in support of a mutation spectrum appears to be consistent, but direct proof of such results in vivo are limited. Using mutS, dam and/or dcm defective Eschericha coli imitator strains, an preliminary experimental system on induction of in vivo mutation spectra of low energy N+ ion beam has been established in this study. It was observed that the mutation rates of rifampicin resistance induced by N+ implantation were quite high, ranging from 9.2 x 10~8 to 4.9× 10~5 at the dosage of 5.2×1014 ions/cm2. Strains all had more than 90-fold higher mutation rate than its spontaneous mutation rate determined by this method. It reveals that base substitutions involve in induction of mutation of low energy nitrogen ion beam implantation. The mutation rates of mutator strains were nearly 500-fold (GM2929), 400-fold (GM5864) and 6-fold larger than that of AB1157. The GM2929 and GM5864 both lose the ability of repair DNA mismatch damage by virtue of both dam and dcm pathways defective (GM2929) or failing to assemble the repair complex (GM5864) respectively. It may explain the both strains had a similar higher mutation rate than GM124 did. It indicated that DNA cytosine methylase might play an important role in mismatch repair of DNA damage induced by N+ implantation. The further related research were also discussed.

Influence of Aluminum Ions Implantation on Corrosion Behavior of Zircaloy-2 Alloy in 1 M H_2SO_4

The specimens were implanted with aluminum ions with fluence ranging from 1× 10^16 to 1× 10^17 ions/cm^2 to study the effect of aluminum ion implantation on the aqueous corrosion behavior of zircaloy-2 by metal vapor vacuum arc source （MEVVA） at an extraction voltage of 40 kV. The valence states and depth distributions of elements in the surface layer of the samples were analyzed by X-ray photoelectron spectroscopy （XPS） and Auger electron spectroscopy （AES）, respectively. Transmission electron microscopy （TEM） was used to examine the microstructure of the aluminum-implanted samples. Glancing angle X-ray diffraction （GAXRD） was employed to examine the phase transformation due to the aluminum ion implantation. The potentiodynamic polarization technique was employed to evaluate the aqueous corrosion resistance of implanted zircaloy-2 in a 1 M H2SO4 solution. It is found that a significant improvement was achieved in the aqueous corrosion resistance of zircaloy-2 implanted with aluminum ions. Finally, the mechanism of the corrosion behavior of aluminum- implanted zircaloy-2 was discussed.

Effect of Ar Ion Beam Implantation on Morphological and Physiological Characteristics of Liquorice(Glycyrrhiza uralensis Fisch)Under Short-Term Artificial Drought Conditions

Ar^＋ ion beam with low energy of 30 keV was implanted into liquorice （Glycyrrhiza uralensis Fisch） seeds at the doses of 0, 600, 900 and 1200 × （2.6 × 10^13） ions/cm^2, respectively. The seeds were sowed in pots and after one month the plants were subjected to different drought conditions for two months. Then the plants＇ morphological and physiological characteristics, antioxidation enzymes and levels of endogenous hormones were investigated. The results showed that ion implantation at a proper dose can greatly enhance the liquorice seedlings＇ resistance against drought stress.

MODIFICATION OF SURFACE MECHANICAL PROPERTIES OF POLYCARBONATE BY B^+ AND O^+ IONS IMPLANTATION

By implanting B+ and O+ ions respectively into polycarbonate (PC) plates, the surface mechanical properties of PC have been improved. Measurement by Nano Indenter II showed that the hardness of samples increased 7-25 times than that before implantation; and the modulus of elasticity raised 2-5 times. The wear-resistance was tested by ball crusher; the width and depth of the wear-streak decreased by 1/3-1/2 or even more. The structure, deformation and appearance were analyzed by using Micro-FTIR Spectra, ESCA method and the steps instrument. These analyses showed that the structure of PC had been modified: a series of new cross-linking yielded, it depends on the Linear Energy Transition (LET) of implanted ions in the high polymer compounds.

Effect of copper ions implantation on the corrosion behavior of ZIRLO alloy in 1 mol/L H_2SO_4

In order to study the effect of copper ion implantation on the aqueous corrosion behavior of ZIRLO alloy, specimens were implanted with copper ions with fluences ranging from 1×10^16 to 1×10^ ions/cm^2, using a metal vapor vacuum arc source （MEVVA） at an extraction voltage of 40 kV, The valence states and depth distributions of elements in the surface layer of the samples were analyzed by X-ray photoelectron spectroscopy （XPS） and Auger electron spectroscopy （AES）, respectively. Glancing angle X-ray diffraction （GAXRD） was employed to examine the phase transformation due to the copper ion implantation. The potcntiodynamic polarization technique was used to evaluate the aqueous corrosion resistance of implanted ZIRLO alloy in a 1 mol/L H2SO4 solution. It was found that a significant improvement was achieved in the aqueous corrosion resistance of ZIRLO alloy implanted with copper ions when the fluence is 5×10^16 ions/cm^2. When the fluence is 1×10^16 or 1×10^17 ions/cm^2, the corrosion resistance of implanted sanaples was bad. Finally, the mechanism of the corrosion behavior of copper-implanted ZIRLO alloy was discussed.

Nitrogen Deposition Via N^+ Implantation:Implications for Primordial Amino Acids Synthesis Revisited

In this paper amino acids synthesis in aqueous solution induced by ion implantation, which was possibly ubiquitous on primitive Earth, is investigated. As a discharge using a graphite rod as the anode under a nitrogen atmosphere was performed against ammonia water, it was found that three kinds of amino acids were produced. They were glycine, serine and alanine. By introducing ion implantation into the carboxylate solution, ammonia and amino acids were also formed via nitrogen deposition/fixation. Another isotopic experiment showed that both OH and H radicals played a crucial role in the arc-discharge-promoted reactions in aqueous solution Therefore, we believe that the impact of ions in the original atmospheric conditions might have functioned as a promoter in the chemical origin and evolution of life.