Bulk Micro Research Articles

Exploring the Soil Structure Analysis of a Subtropical Watershed by Introducing a Blanket Physico‐Hydraulic Health Index

ABSTRACTMultiple disturbed and undisturbed soil samples were collected to assess the soil structure health in support of water use and management in a subtropical watershed, which is composed of shallow Entisols, near to Canguçu, RS state—Brazil. Various physico‐hydraulic properties related to soil structure, such as bulk density, total, micro and macroporosity, saturated hydraulic conductivity, organic carbon, soil water retention curve (SWRC), and the ranges of plant available water (PAWC) and drainable porosity (DP) were measured to be analyzed. The hydraulic‐energy indices of soil aeration and water retention were determined by integrating the areas under SWRC. Combining these properties with the contents of sand and clay, a unique blanket soil physico‐hydraulic health index (BSPHI) was formulated and applied to investigate the impact of land use and management on the soils of the Ellert Creek Watershed (ECW), thereby supporting soil physical health analysis and, consequently, the analysis of water and human health. The favorable outcomes found in the ECW soils under annual crops indicated good root aeration in the surface layer due to the balance between DP and PAWC. The BSPHI results showed that only about 19% of the areas exhibited unhealthy physical health. The soil structure in pasture areas of ECW was not significantly impacted by the extensive cattle grazing, whereas lands under native forest served as a control for the natural soil quality status. The BSPHI successfully captured small changes in soil structure, regardless of land use and management, highlighting its potential as a promising tool for evaluating soil health by assessing the soil physical quality.

Preparation of bulk micro–mesoporous silica-supported ZnO via silicic acid as a desulfurizer

Silicic acid solution, which is prepared from water glass followed by extraction with tetrahydrofuran (THF), is focused on an environmentally friendly and inexpensive source of silica. In this study, we aimed the preparation of bulk porous silica with low environmental impact and cost, and desulfurization of its supported ZnO was investigated. Bulk porous silica was prepared by the condensation of silicic acid/THF in the presence of Pluronic P123. Suitable condition was investigated for the formation of crack-free bulk body with high surface area and reproducibility under the molar ratio of H2O/Si and Si/Pluronic P123 on 121 and 100, respectively. From nitrogen adsorption–desorption measurements, this bulk porous silica was categorized into micro–mesoporous silica. Moreover, Pluronic P123 was extracted and recycled. Bulk porous silica-supported 15 wt% ZnO was prepared by the impregnation of ZnCl2 followed by calcination in air. The desulfurization ability was 8.7 mg/g.Graphical

The effect of RTP pretreatment on slip-lines of argon annealed silicon wafer

In this research, Rapid Thermal Process (RTP) pretreatment technology was used to study the slip-lines of 12-inch light boron-doped silicon wafer with Oxidation Induced Stacking Fault (OISF) ring which will be used for argon annealing. X-ray Diffraction Topography (XRT) test results were shown that Rapid Thermal Processing (RTP) pretreatment below 1250 °C would lead to the deterioration of slip-lines during argon annealing, and that RTP pretreatment no less than 1250 °C would eliminate slip-lines. Bulk Micro Defects (BMD) tests show that RTP pretreatment can deteriorate or eliminate slip-lines resulted from argon annealing. When the RTP pretreatment temperature is lower than 1250 °C, the native BMD nuclei smaller than the critical size will eliminate. During argon annealing, the growth of the residual native BMD nuclei formed during ingot pulling process is the dominant process, while formation and growth of new nuclei are less, resulting in both the reduction of BMD density and broadening distribution of BMD size. Then we see the slip-lines of silicon wafer will become worse due to the increase of thermal stress in the silicon wafer. However, when the RTP pretreatment temperature is no less than 1250 °C, the native BMD nuclei will be completely eliminated and a vacancy enriched layer will be formed in the silicon wafer. During argon annealing, vacancies promote the uniform nucleation of BMD, the density of BMD increases and the size distribution becomes narrow, and the thermal stress in the silicon wafer is relatively lower, thus the slip-lines are eliminated.

Design, Optimization and Performance Assessment of Single Port Film Bulk Acoustic Resonator through Finite Element Simulation.

In this paper, the study is supported by design, FEA simulation, and practical RF measurements on fabricated single-port-cavity-based acoustic resonator for gas sensing applications. In the FEA simulation, frequency domain analysis was performed to enhance the performance of the acoustic resonator. The structural and surface morphologies of the deposited ZnO as a piezoelectric layer have been studied using XRD and AFM. The XRD pattern of deposited bulk ZnO film indicates the perfect single crystalline nature of the film with dominant phase (002) at 2θ = 34.58°. The AFM micrograph indicates that deposited piezoelectric film has a very smooth surface and small grain size. In the fabrication process, use of bulk micro machined oxide (SiO2) for the production of a thin membrane as a support layer is adopted. A vector network analyzer (Model MS2028C, Anritsu) was used to measure the radio frequency response of the resonators from 1 GHz to 2.5 GHz. As a result, we have successfully fabricated an acoustic resonator operating at 1.84 GHz with a quality factor Q of 214 and an effective electromechanical coupling coefficient of 10.57%.

Interpenetrating Polymer Networks of Polyacrylamide with Polyacrylic and Polymethacrylic Acids and Their Application for Modified Drug Delivery - a Flash Review.

Polyacrylic and polymethacrylic acids, in combination with polymers such as polyacrylamide, provide the ability for controlled and sustained drug delivery since they represent pHand temperature responsiveness. In addition, the synthesis techniques can be used to develop a higher level of supramolecular structures as the interpenetrating polymer networks - as bulk hydrogels or micro-/nanogels. They can provide the opportunity to organize and build up state-ofthe- art carriers for different types of drugs, thus providing the ability to control their loading capacity and drug release performance. This flash review aims to summarize the efforts for synthesizing such interpenetrating polymer networks and their properties and to demonstrate the authors' contributions to this field.

Speciation of Zn and Cd in sierozem soil, northwest China: bulk EXAFS and micro synchrotron X-ray fluorescence.

Previous research studies have confirmed that Zn and Cd are the most predominant heavy metals in the Baiyin district, Gansu province, China. Furthermore, the speciation of Zn and Cd is a key factor in controlling the mobility, bioavailability, and toxicity of metals in Zn/Cd co-contaminated soil. In this study, the speciation of Zn and Cd in different types of agricultural soils including the Yellow River irrigated soil (s3) and sewage irrigated soil (s1 and s2) was investigated and compared by a combination of sequential extraction, bulk X-ray absorption fine structure (XAFS), and micro-X-ray fluorescence (μ-XRF) techniques. The results of the speciation quantified by XAFS were in general agreement with those obtained by sequential extraction, and the combination of both approaches allowed a reliable description of Zn/Cd speciation in soil. The speciation of Zn in the s1 soil exposed around the smelter was similar to speciation of Zn in the sewage irrigated s2 soil. In both soils, Zn was predominantly present as Zn-Al LDH (31-36%), Zn adsorbed on calcite (37-47%), and primary minerals (14-18% sphalerite and 9% franklinite). In contrast, the proportions of organic Zn (23%) and Zn-Al LDH (53%) were significantly higher in the Yellow River irrigated s3 soil, while that of Zn-calcite (24%) was lower. This indicated that Zn in s3 was less mobile and bioavailable than that in s1 and s2 soils. The content of bioavailable Zn in s3 was much lower than the background value and Zn did not pose a threat to the Yellow River irrigated soil. In addition, Cd was strongly correlated with Zn content and exhibited a simpler speciation. Cd adsorbed on illite and calcite was found as the major species in both soil types, posing higher migration and toxicity to the environment. Our study reported the speciation and correlation of Zn/Cd in sierozem soil for the first time and provided a significant theoretical basis for remediation actions to minimize Zn/Cd risks.

Dependência espacial da produtividade da cana-de-açúcar, altitude e atributos físicos do solo em um transecto

ABSTRACT Soil management carried out in areas with sugarcane production causes changes in the soil physical attributes, and geostatistics makes it possible to study the behavior of the spatial distribution of these variations. This study aimed to evaluate the behavior of the spatial distribution of sugarcane yield averages according to the altitude and soil physical attributes along a transect in Goiana, Pernambuco, Brazil. Sugarcane yield averages, altitudes, and soil physical attributes, such as soil bulk density, total porosity, micro and macro porosity, sand (total, coarse, and fine), silt, and clay, in the 0.00-0.20 and 0.20-0.40 m soil layers were determined at 20 m intervals along the transect characterized by a toposequence of Ultisols and Spodosols. Exploratory data analysis was performed with the aid of descriptive statistics. The analysis of spatial dependence was performed using geostatistics. Pairs of semivariances were obtained using the GS+ software. The development and adjustment of the semivariograms were performed using the GEOEAS geostatistical tool. The highest contents of the finest soil particles were found in the lowest sections of the transect, in the 0.20-0.40 m soil layers. The highest amount of macropores was observed in the subsurface soil layer. The areas with the lowest amount of micropores showed the lowest average sugarcane yield, around 32.00 t.ha-1. The geostatistical model that best fitted the data set was the spherical model.

Two-dimensional BMD, BSF, ring-OISF and COP distributions in a dislocation-free ingot grown by the NOC method

The noncontact crucible (NOC) method has a large and deep low-temperature region in Si melt to grow a uniform large Si single ingot. The theoretical simulation pointed out that the lowest vacancy or interstitial Si atom area appears in the region with the smaller ratio between temperature gradients at melt surface and growing interface. The growth condition to obtain this region is suitable for the NOC method. The quality of a NOC ingot was first evaluated by determining the distribution of bulk micro defect (BMD), bulk stacking fault (BSF), oxidation induced stacking fault (OISF) and crystal originated particle (COP) in the cross section of the dislocation-free ingot. A ring-OISF or BSF can be clearly observed on the cross section cut from the middle and tail parts of the ingot. BMD can be observed inside and outside the ring-OISF. By estimated comparison to the none-doping case, CV (=CI) at cross point clearly has a trend to increase for the high B-doing case (5 × 1019 cm−3), where CV and CI are concentration of vacancy and interstitial Si atom, respectively. Nevertheless, in comparison with the distribution of COP in Cz and NOC ingots, COP cannot be detected inside the ring-OISF in the NOC wafer under the same etching process as many COP can be observed in the Cz wafer. This may be a unique feature for NOC growth.

An Assessment of the Role of Combined Bulk Micro- and Nano-Bubbles in Quartz Flotation

Bulk micro-nano-bubbles (BMNBs) have been proven to be effective at improving the flotation recovery and kinetics of fine-grained minerals. However, there is currently no research reported on the correlation between the properties of BMNBs and flotation performance. For this purpose, aqueous dispersions with diverse properties were created by altering preparation time (0, 1, 2, 3, 5, and 7 min), aeration rate (0, 0.5, 1, 1.5, and 2 L/min) and aging time (0, 0.5, 1, and >3 min). Micro- and nano-bubbles were characterized using focused beam reflection measurements (FBRM) and nanoparticle tracking analysis (NTA), respectively. The micro-flotation of quartz particles was performed using an XFG-cell in the presence and absence of BMNBs with Cetyltrimethylammonium bromide (CTAB) as a collector. The characterization of bubble sizes showed that the bulk micro-bubble (BMB) and bulk nanobubble (BNB) diameters ranged from 1–10 μm and 50–400 nm, respectively. It was found that the preparation parameters and aging time considerably affected the number of generated bubbles. When BNBs and BMBs coexisted, the recovery of fine quartz particles significantly improved (about 7%), while in the presence of only BNBs the promotion of flotation recovery was not significant (2%). This was mainly related to the aggregate via bridging, which was an advantage for quartz flotation. In comparison, no aggregates were detected when only nano-bubbles were present in the bulk solution.

(G02 Best Paper Award Winner) Development Of High Resistivity FD-SOI Substrates for mmWave Applications

The mmWave era opens up the door to revolutionary applications in the fields of communication, radar, imager, security, etc. FD-SOI CMOS technology is entering the mmW realm providing undeniable benefits in terms of data-rates, bandwidth, latency and power consumption improvements. The high resistivity substrate option is seen as a major booster to reach ultimate mmW performances. The engineering challenges related to this new wafer generation are addressed in this paper.In the different options for highly resistive silicon, low and high interstitial oxygen (Oi) materials are the most common ones, typically used to reach resistivity performance on SOI handles. Those materials are less compatible with FD-SOI technology, as they can be very sensitive to slip-line issues or wafer deformation, in specific SOI processing and customer’s line, possibly leading to overlay error. In addition, we can encounter inspectability and co-integration issues due to Crystal Originated Particules (COPs) presence for high Oi substrates. For the targeted technologies with FD-SOI, equal or below 28 nm, the handle properties will be key, as deformation and inspectability considerations are even more critical.One of the main challenges was to develop specific materials and processes to get both good resistivity and stability towards fabrication processes (SOI line and customer processing), and good mechanical behavior towards slip-line and potential deformation leading to error, together with low COPs handle material.In this paper, we will show how substrates were engineered specifically, to reach the appropriate resistivity targets around 1000 Ω.cm, and to be stable in depth with different additional anneals, in order to control compatibility with customer processes. In addition, we managed to achieve good performances in terms of mechanical behavior, such as slip-line generation during fabrication processes. We also had no overlay issues usually linked with slip-lines or excessive Bulk Micro Defects (BMD) presence in depth, generating dislocations and plastic deformation.We will review the material and process steps requirements to reach the best performances.The initial material requirements will be the oxygen content, together with the resistivity. The process requirements will be the final oxygen precipitation status, affected by specific thermal treatments and presence of sites for BMD nucleation and growth.A specific precipitation range will lead to good robustness towards both slip-lines sensitivity and overlay risks, by creating enough BMDs but not in excess. Besides, this specific precipitation state also helps to decrease the amount of residual interstitial oxygen left inside the High Resistivity substrate, and then decreases the oxygen thermal donor generation during back-end treatments in the 375-425°C range, improving resistivity stability.We will present all the characterizations performed on final SOI wafers, and after additional treatments, to highlight both handle substrate resistivity stability and mechanical robustness.Specific measurements were carried out to ensure that going from standard to high resistivity substrates did not adversely impact the behavior of logic devices. Test structures were implemented with 28 nm design rules on FD-SOI substrates with either 10 Ω.cm or 5 kΩ.cm handle resistivity. Compared figures of merit included transistors’ VTH and minimum gate length devices Ion/Ioff tradeoff as well as several devices built in the bulk of the wafer such as bipolar devices, diodes and capacitors. Obtained results will be shown to be within the natural process dispersion.Those substrates being destined to RF and mmWave applications, their performance was measured in terms of linearity and attenuation using coplanar waveguides built directly on top of the 20 nm buried oxide. Second harmonics measurements up to 28 GHz of fundamental frequency will be shown. The small signal measurements results will be compared to simulations including a thicker dielectric mimicking the very thick back-end of line available in advanced nodes.In conclusion, we will summarize how specific material for eSoC.1-HR handle was developed, showing performances in agreement with expectations on resistivity stability and mechanical robustness. Those substrates are leading to improved RF parameters compared to standard FD-SOI substrates, without degrading logic devices parameters.

Bioinspired Hydrogels as Platforms for Life-Science Applications: Challenges and Opportunities.

Hydrogels, as interconnected networks (polymer mesh; physically, chemically, or dynamic crosslinked networks) incorporating a high amount of water, present structural characteristics similar to soft natural tissue. They enable the diffusion of different molecules (ions, drugs, and grow factors) and have the ability to take over the action of external factors. Their nature provides a wide variety of raw materials and inspiration for functional soft matter obtained by complex mechanisms and hierarchical self-assembly. Over the last decade, many studies focused on developing innovative and high-performance materials, with new or improved functions, by mimicking biological structures at different length scales. Hydrogels with natural or synthetic origin can be engineered as bulk materials, micro- or nanoparticles, patches, membranes, supramolecular pathways, bio-inks, etc. The specific features of hydrogels make them suitable for a wide variety of applications, including tissue engineering scaffolds (repair/regeneration), wound healing, drug delivery carriers, bio-inks, soft robotics, sensors, actuators, catalysis, food safety, and hygiene products. This review is focused on recent advances in the field of bioinspired hydrogels that can serve as platforms for life-science applications. A brief outlook on the actual trends and future directions is also presented.

(Invited) Impact of the Substrate Specifications on the Extended Defects Induced by the Deep Trench Isolation

STMicroelectronics invented and is a leader in BCD technology, which integrates analog, digital and power technologies to address a broad range of power management, data acquisition and actuator applications for automotive and other uses. The silicon wafers of the BCD technology are epitaxial, (100)-oriented, p-/p+ silicon wafers. The epitaxial layer has a boron doping in the order of 1015cm-3, whereas the substrate has a boron doping in the order of 1018cm-3. Starting with the technology node of 0.16μm the Deep Trench Isolation (DTI) is integrated to improve the isolation between internal blocks and to reduce interferences among them. The DTIs are trenches of several tenth of microns, filled by silicon dioxide and polycrystalline silicon. However, the DTI induces a certain crystal defectivity because of the mechanical stress generated during the thermal processes. Architectural and process changes can mitigate the mechanical stress, but it cannot be enough in case the DTI reaches the bulk silicon that is highly boron-doped and where the Bulk Micro Defects (BMDs) are present. Indeed, under stress, these defects facilitate the generation of dislocations and reduce the mechanical resistance of the silicon. This work find out that the depletion of BMDs in the silicon area around the bottom of DTI to be crucial in reducing the dislocation nucleation, expansion and propagation. In other words, the creation of a Denuded Zone in the top part of the p+ bulk beneath the p- epitaxy gets crucial.According to the literature, the thermal history of the first part of the process flow is key in shaping a Denuded Zone. So, the first high temperature treatments denude the superficial silicon layer from the oxygen, whereas some of the following thermal treatments, ones at lower temperatures, lead to the nucleation of BMDs and the last operations at high temperature in the process flow increases the BMDs size. By acting on the substrate resistivity and on the content of interstitial oxygen (Oi), it is possible to modulate the BMD generation, for a fixed process flow. Indeed, as the boron doping and the Oi decrease, the BMDs formation is hindered and the oxygen denuding is promoted. Therefore, the substrate specifications of Oi and resistivity impact the crystal defectivity generated by the interaction of the DTIs with the BMDs.All through this work the measurement of the Denuded Zone is carried out by means of the preferential chemical etching, i.e Secco d’Aragona, but also Micro-photoluminescence technique at room temperature, as implemented in the tool EnVision by Semilab. The effectiveness of the decreasing of boron and Oi content in reducing the dislocation generation is tested with a dedicated test structure. This structure is a collection of Power MOS on buried layer with a DTI layout prone to dislocation generation. The design has been developed in order to maximize the silicon area dedicated to the Power devices, characterize the performances of Power devices of different architectures (Drift MOS with Buried Layer, Drain extension), create DTI with spacing, shape and number compatible with our device requirements but critical in mechanical stress generation. The breakdown voltage and the leakage current that are sensitive to the crystal defect are measured on this power MOS structures.It will be shown that a moderate boron decrease and a small decrease of Oi increases the Denuded Zone by a huge amount and reduces the BV failure rate by decades (from 8% to the baseline of 0.2%), thus a huge gain resulting from narrower wafer specifications.

Soil quality assessment using erosion-sensitive indices and fuzzy membership under different cropping systems on a Ferralsol in Brazil

The objective of this study was to evaluate soil quality under different cropping systems through two erosion-sensitive indexing methodologies applying fuzzy membership functions to a minimum data set (MDS) of soil properties. The experiment was conducted in a Ferralsol, in annual growing cycles from 2007 to 2014. The evaluated cropping systems included individual and intercropped treatments using: sunn hemp (Crotalaria juncea L.), pearl millet (Pennisetum glaucum L.), jack bean (Canavalia ensiformis L.), pigeon pea (Cajanus cajan L. Huth), and maize (Zea mays L.). Sampling in an adjacent area under native forest was also performed as a reference ecosystem. Soil properties such as bulk density, micro-, macro- and total porosity, aggregates stability, laboratorial soil fertility properties, and soil organic matter content were selected as MDS of physical and chemical properties, being used to compute two soil quality indices: 1) Integrated Quality Index (IQI), and 2) Nemoro Quality Index (NQI). Soil quality results showed the lowest values of soil and water losses corresponded to the largest soil quality indices evidencing that the usage of water-erosion-sensitive indices can be useful for the prediction of soil quality status. The selected MDS of soil properties were adequate indicators of soil quality as reduced water erosion was associated with large soil quality indices, e.g. negative correlation between soil macroporosity and soil erosion processes. The fuzzy methodology was effective in predicting soil quality using a MDS of soil property indicators, which can benefit various stakeholders in their decision-making process to ensure continuing and sustainable crop production.

PRODUCTION AND CHARACTERIZATION OF ACTIVATED CARBONS FROM SUGARCANE BAGASSE FROM CHEMELIL SUGAR FACTORY, COMPARED WITH COMMERCIAL ACTIVATED CARBONS

In Kenya activated carbon is imported yet we have enough bagasse that can be used in its production. The activated carbon from bagasse adds economic value to the bagasse and the processing excess bagasse provides for good utilization and management of the bagasse as a waste. The objective was to produce activated carbon from bagasse from Chemelil sugar factory on laboratory scale in a fabricated retort and furnace at selected conditions of temperature and time, characterize and give a comparison with the commercial activated carbons. Using molasses as a binder, ratio 1:1, the bagasse and molasses mixture was compressed into pellets in an extruder, heated to produce a char, and then activated using carbon dioxide, before finally being ground into powdered activated carbon. Carbonization was done in a retort, while the heating was done by two gas burners. Temperature, was controlled between 300 – 700 oC. The carbonized material (char) was cooled and ground to powder. Sample activation was conducted in an atmosphere of carbon dioxide passing through a chrome-nickel pipe with a gas distributor mounted in a furnace of porcelain cylinder with a metal sheet having one end closed. Air and nitrogen were used to control burning and the temperature of the furnace was controlled to between 300 – 600 oC. The activated carbons produced were characterized for their physical properties (bulk density, surface area, and micro pore volume and pore size), chemical properties (ash, pH, conductivity) and compared with selected two commercial activated carbons. The results showed that carbon materials activated from bagasse for 5 h at a temperature of 600 oC had similar characteristics with the commercial ones and therefore an inexpensive substitute with further process development on surface area.

Critical Aspects of AGC Emerging from Optimal Control to Machine Learning Techniques

With the emphasis towards renewable energy lot more advancement has been done in the field of electric energy system and it is expected that future energy system may have wind power dominating control areas or hydro power be it bulk hydro or micro hydro based power generations in order to cater the rising energy demands of the modern society. Hence, automatic generation control (AGC) plays a crucial role in the modern electrical energy system in order to maintain the frequency standards to nominal value besides maintaining the power interchange between the interconnected controls areas in order to distribute value and cost effective power. This paper presents the literature survey related to some of the critical aspects of AGC such as diverse sources power generations, hydro dominating control areas, wind power based power generations and applications of flexible alternating current transmission system (FACTS) in AGC. This paper also discusses the novel control designs based on the concept of optimal control, output vector feedback, model predictive control, robust control and finally the machine learning based AGC designs are explored and the critical gaps among the available research work are well presented and discussed.

Critical Aspects of AGC Emerging from Optimal Control to Machine Learning Techniques

With the emphasis towards renewable energy lot more advancement has been done in the field of electric energy system and it is expected that future energy system may have wind power dominating control areas or hydro power be it bulk hydro or micro hydro based power generations in order to cater the rising energy demands of the modern society. Hence, automatic generation control (AGC) plays a crucial role in the modern electrical energy system in order to maintain the frequency standards to nominal value besides maintaining the power interchange between the interconnected controls areas in order to distribute value and cost effective power. This paper presents the literature survey related to some of the critical aspects of AGC such as diverse sources power generations, hydro dominating control areas, wind power based power generations and applications of flexible alternating current transmission system (FACTS) in AGC. This paper also discusses the novel control designs based on the concept of optimal control, output vector feedback, model predictive control, robust control and finally the machine learning based AGC designs are explored and the critical gaps among the available research work are well presented and discussed.

English

Types of land use practice significantly affect the soil physico-chemical properties. Four different land use types were selected (natural forest, bamboo plantation, degraded forest and agricultural land) to analyze the effect of land uses change on soil chemical and physical properties. Among all land use pattern, the highest water holding capacity (40.06±0.74%), porosity (0.539±0.011%), soil macro-aggregates (64.16±2.64%), soil organic carbon (0.84±0.054%) and soil total nitrogen (0.123±0.013%) were found to be under natural forest, closely followed in decreasing order by bamboo plantation, degraded forest and agricultural land. Unlikely, bamboo plantation was higher in moisture content (2.78±0.23%), whereas agricultural land was lower in moisture content (2.14±0.5%), though no significant differences were observed among land use types. Soil organic carbon was significantly affected by different land use practices. In contrast to this, agricultural land was higher in bulk density (1.37±0.0193 g/cm3) whereas natural forest was lower in bulk density (1.220±0.0288 g/cm3). Bulk density, soil organic carbon, soil total nitrogen, water holding capacity and porosity were significantly affected by land use changes. Furthermore, the correlation of analysis showed that soil organic carbon, soil total nitrogen, moisture content, porosity, water holding capacity, soil macro aggregates were positively correlated to each other and negatively correlated with bulk density, meso and micro soil aggregates at p<0.05. The results of this study will help to develop future plan about land use and soil management regarding soil carbon dynamics and climate change mitigation. Key words: Land use type, land use change, soil physico-chemical properties.

Changes in soil chemical and physical properties in pasture fertilised with liquid swine manure

ABSTRACT: Chemical and physical properties of soil can be altered with the successive application of liquid swine manure (LSM), also known as slurry. Therefore, monitoring the impact of LSM is essential to an assessment of the potential agronomic and environmental benefits and risks associated with management practices. The aim of this study was to evaluate the effects of LSM on the chemical and physical attributes of soil under pasture (Cynodon spp.), located in southern Brazil. Four areas were sampled: three areas cultivated with Cynodon spp. pasture with successive applications of 200 m3 ha–1 y–1 of LSM for three, eight and 15 years; and untreated native forest as a reference. The soil attributes evaluated were: organic carbon (OC), active (pH water) and potential acidity (H + Al+ 3), nutrient availability (i.e., P, K, Ca, Mg, Cu and Zn), soil bulk density, macro, micro and total porosity. Successive applications of LSM on pasture reduced soil active acidity, and increased the soil organic C and plant-available N, P, Ca, Mg, Cu and Zn contents. These effects were more intense with time and in the shallowest layers, i.e. 0-10 cm. Excessive increases in P, Cu and Zn in the soil should be carefully monitored to minimize the contamination risks to soil, ground and surface waters. Soil physical attribute changes were more associated with land use (pasture versus native forest) than LSM use, and LSM applications induced slight improvements in the soil structural quality over time.

The effects of pre-annealing on oxygen precipitation in silicon P/P-epitaxial wafers

Abstract Herein, the effect of pre-annealing on oxygen precipitation in a silicon P/P-epitaxial wafer was investigated using an experimental approach. Czochralski-grown silicon wafers were annealed at 800–900 °C to enhance their bulk micro defects (BMDs), before the epitaxial growth process. The effect of the pre-annealing temperature on oxygen precipitation was greater than that of the pre-annealing time, and the effect of pre-annealing temperature varied between polished and epitaxial wafers. Regarding pre-annealed epitaxial wafers that were annealed at low temperatures, the pre-annealing time also had as large an effect on BMD formation as the pre-annealing temperature. These experimental results were used to determine the optimal pre-annealing temperature for enhancing oxygen precipitation in epitaxial wafers. The experimental results regarding the optimal conditions were consistent with prior hypotheses. Crystal originated particles (COPs) and COP-free crystals exhibited their highest BMD density values at similar pre-annealing temperatures.

Near‐Surface Defect Control by Vacancy Injecting/Out‐Diffusing Rapid Thermal Annealing

Rapid thermal annealing (RTA) can be applied to dissolve small defects such as voids or small‐sized oxygen precipitates and to manipulate vacancies in a specific depth from the surface. This can be achieved at elevated temperatures around 1300 °C and via NH3 dissociation at the surface at temperatures &gt;1150 °C. In an earlier study (Araki et al., 2013), it had been demonstrated already that even under oxidizing ambient, enhanced bulk micro defects formation around 1300–1350 °C can occur. The near‐surface region is monitored via its homogeneity of precipitation and in‐depth vacancy profiling by Pt‐diffusion. Simulations of defect dissolution during RTA processes are performed up to 1290 °C under different ambient. The size‐dependent defect dissolution behavior is predicted and verified by measurement of the gate oxide integrity.