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Driven by manufacturing supply reform and regional industrial transformation and upgrading, village industrial parks are key areas for deepening urban renewal. The complex relationship between various property rights actors is a key factor limiting the sustainable development of village industrial parks, and thus attracts considerable research. However, existing research is limited to individual cases and lacks systematic approaches to provide effective guidance for the renovation of village industrial parks. In addition, the paper summarises the participation pathways and characteristics of 12 typical cases of village industrial parks in the PRD. This is particularly true for rural industrial parks. The study identifies five scenarios based on the renewal of village collective ownership (government warehousing, land lease to developers, land lease to operating companies, land lease to enterprises, independent management); five situations based on the renewal of market enterprises’ rights of use (regular leasing, government support, abolition on expiry, introduction of enterprises, autonomous management); and four situations based on the renewal of government management rights (land expropriation, unified lease management, policy stimulation, supervision and management). The results are valuable for the research of urban regeneration and sustainable development in the context of government ownership.

In order to explore the segmented relationship between the segmented rating results of Baijiu and the segmented characteristics of alcohol content and cumulative flow in the distillation process and to verify whether different liquor categories can achieve rating through the segmented characteristics of alcohol content and cumulative flow, in view of this, combined with the Industrial Internet of Things (IIoT) technology and online detection and analysis of alcohol and cumulative traffic, its accuracy can reach ±0.5%, ±1%, with the integration of Baijiu categories, sources, liquor characteristic conditions, and other multisource data, to achieve Baijiu segmented rating data reconstruction, the use of standard error and standard deviation as evaluation indicators, quantification of distilled liquor alcohol, and cumulative flow segmented characteristics to form a liquor rating strategy, so as to use the Arduino platform control motor to achieve automatic grading of Baijiu. Experiments show that the relative error between automatic rating and manual rating is less than 10%, which shows that automatic rating can be better applied to the actual brewing process. It provides a solution for the digitization and standardization of Baijiu grading.

Background Previous research has identified a significant, positive relation between childhood maltreatment and depressive symptoms. However, the findings required replication at the within-person level. Moreover, the mediating mechanism of locus of control accounting for their relations has yet to be fully evaluated. Thus, this study examined the dynamic longitudinal relations between childhood maltreatment and depressive symptoms including whether locus of control functioned as a mediator between them after separating between-person effects from within-person effects. Methods A sample of 4110 Chinese children (50.60% boys; Mage = 9.89 at Wave 1) covering the transitional period from middle childhood to early adolescence completed a package of self-report measures on 5 occasions across 2.5 years, using 6-month intervals. Random Intercept Cross-Lagged Panel Models were applied to disaggregate between- and within-person effects. Also, alternative Cross-Lagged Panel Models were applied. Results Locus of control played a mediating role in the reciprocal relations between childhood maltreatment and depressive symptoms at the within-person level. Limitations Some limitations existed in the measures. Moreover, sexual abuse was not investigated in this study. Conclusions The findings highlighted the mediating role of locus of control in the reciprocal relations between childhood maltreatment and depressive symptoms at the within-person level, suggesting that interventions targeted at promoting internal locus of control may help prevent the developmental pathway from childhood maltreatment to depressive symptoms and vice versa from middle childhood to early adolescence.

Prescribed burning is a useful tool in a suburban forest of subtropical Australia for bushfire risk management. Toohey Forest has been managed by controlled burns and was used in this study. This study examined the long-term impacts of prescribed burning on biological nitrogen fixation (BNF) of understory acacia species estimated by 15 N natural abundance method, water use efficiency (WUE) as reflected in foliar carbon isotope composition (δ13C), and plant growth 6–14 years after prescribed burning in a suburban Toohey forest ecosystem of subtropical Australia. Four sites (S1, S2, S3, and S4) were established in Toohey Forest, Queensland, Australia. Foliar samples were collected from two understory species of acacia (A. leiocalyx and A. disparimma) and reference plants (E. psammitica) at each study site for three seasons (growing seasons of Spring October 2018 and Autumn May 2019, and non-growing season of Winter August 2019). Foliar total nitrogen (N) concentrations of A. leiocalyx were higher at sites of S1, S3, and S4 than those of A. disparimma after 6–14 years of prescribed burning. Both species still depended upon BNF for their N supply, with a higher dependence maybe in winter than in summer at S3. The highest BNF rates for A. leiocalyx at all sites were also found in the winter of August 2019, while the lowest BNF rates were detected during the autumn of May 2019. The BNF was estimated as 56.5% for A. leiocalyx and 52.8% for A. disparimma at S1, with the corresponding values of 74.6% at S2, 63.4% at S3, and 85.0% at S4, respectively. This study demonstrates that A. disparimma for S1, S2, S3, and S4 had relative higher WUE than A. leiocalyx in the winter of August 2019 after 6–14 years of prescribed burning. There was a significant higher plant growth rate (tree height) of A. leiocalyx at sites of S1, S2, and S4, compared with that of A. disparimma. Both young acacia plants were more active in BNF than older plants, with the BNF peaked between 6 and 8 years after prescribed burning. Conversely, BNF was lower after 9–14 years of prescribed burning. There were significant and positive relationship between foliar δ13C and δ15N, highlighting the role of BNF in improving plant WUE and subsequently tree growth in the suburban native forest.

The organic components in fresh litters are important chemical traits for evaluating the initial quality that controls decomposition of plant litter. This study aimed to assess the seasonal dynamics and drivers of organic components in four dominant fresh litters and their variations at different gap positions in an alpine forest on the eastern Tibetan Plateau. We measured the water- (WSE), organic- (OSE), acid-soluble extractables (ASE) and acid-unhydrolyzable residues (AUR) in fresh litters of fir (Abies faxoniana), cypress (Sabina saltuaria), azalea (Rhododendron lapponicum), and cherry (Cerasus duclouxii) at the gap center, gap edge, and under the closed canopy over 1 year in an alpine forest. The contents of organic components significantly varied among litter species and collecting time, and the ASE content also showed significant variations among gap positions. Manganese (Mn) was negatively related to the OSE content, and dissolved organic carbon (DOC) was the most significant factor affecting WSE and AUR contents. Magnesium (Mg) was the factor of great magnitude that significantly influenced the ASE content, and the correlation coefficient between Mg and ASE in the gap center was higher than that in other gap positions. The contents of organic components were markedly controlled by litter species over time, and ASE content varied significantly after gap formation. The seasonal dynamics of these organic components were strongly mediated by litter nutrients, such as Mg, Mn, calcium (Ca), and nitrogen (N), while DOC was a significant factor controlling WSE and AUR contents in fresh litters in this alpine forest.

Humification of plant detritus is an important pathway for soil organic matter formation. The long-standing studies considered that humification proceeds at very late stages of litter decomposition, while the degree of humification in newly shed litters before decomposition remains unclear. In this study, we aimed to explore the degree of humification and conjugate structures of humic substances in newly shed litters, and their variations between litter types with different chemical components and between seasons with different environmental conditions. In this study, we collected fresh foliar (evergreen vs. deciduous and tree vs. shrub), twig, flower, and fruit litters by litter traps in a subalpine forest on the eastern Tibetan Plateau monthly from April to November 2016. The humification degrees of these newly shed litters were evaluated by the optical properties (i.e., ΔlogK, E4/E6, and A600/C) of the alkaline-extracted humic acid-like solutions. E4/E6 and ΔlogK are often used to evaluate the degree of humification, and these values were also used to classify the maturity levels of humic substances. We found that the ΔlogK, E4/E6, and A600/C values varied greatly among seasons with a higher degree of humification observed in August than in the other months for foliar litter. Compared with other litter components, foliar litter exhibited higher ΔlogK, E4/E6, and A600/C values, indicating that fresh foliar litter had a lower degree of humification than the other litters. Twig litter had more stable and abundant precursors of soil organic matter with a higher degree of humification. Moreover, higher degrees of humification with lower ΔlogK and E4/E6 values were observed in evergreen and tree litter species than in deciduous and shrub species, indicating that deciduous and shrub species retained strong abilities to sequester carbon (C). The degree of humification in newly shed litters was strongly affected by chemical components. Twig litter had more stable and abundant precursors of soil organic matter with high degree of humification. Deciduous species and shrub species retained strong abilities to sequester C in cold biomes. Additionally, the humic substances in newly shed litters were very young (type Rp), as assessed by the ΔlogK and A600/C values according to the Kumada’s classification, implying that these humic substances might have faster turnover times but strongly contribute to soil organic matter formation in this subalpine forest.

Previous cross-sectional and unidirectional longitudinal studies have investigated the associations among perceived parental warmth, positivity, and depressive symptoms among children and adolescents without distinguishing between-person effects from within-person effects.The current study aimed to examine the dynamic longitudinal associations among perceived parental warmth, positivity, and depressive symptoms, including whether positivity functioned as a mediator of the reciprocal relations between perceived maternal/paternal warmth and depressive symptoms at the within-person level encompassing middle childhood to early adolescence.A sample of 3765 Chinese students (45.8% girls; M age = 9.92 years, SD = 0.72; range = 9-12 years at Time 1) completed self-report measures on 4 occasions across 2 years, using 6-month intervals. Random-Intercept Cross-Lagged Panel Models were employed to disentangle between- and within-person effects.(a) Perceived maternal/paternal warmth and depressive symptoms reciprocally and negatively predicted each other; (b) positivity and depressive symptoms reciprocally and negatively predicted each other; (c) perceived maternal/paternal warmth and positivity reciprocally and positively predicted each other; (d) depressive symptoms indirectly predicted perceived maternal/paternal warmth via positivity; (e) perceived maternal warmth displayed earlier and more stable effects on positivity and depressive symptoms than perceived paternal warmth; and (f), no childhood sex differences existed in the observed associations.These findings highlight the longitudinal within-person transactions among perceived parental warmth, positivity, and depressive symptoms, and the differential roles of perceived maternal/paternal warmth. These findings may help provide a potential theoretical framework through which to precisely identify objectives for early intervention.

Previous research has investigated the associations among childhood maltreatment, self-control, and aggression among adolescents without distinguishing between-person effects from within-person effects. Thus, we evaluated the dynamic longitudinal associations among childhood maltreatment, self-control, and aggression, including whether self-control functioned as a mediator of the reciprocal relations between childhood maltreatment and aggression at the within-person level after disentangling between- and within-person associations. A sample of 2050 Chinese early adolescents (43.69% girls, Mage = 10.39 years, SD = 0.55, range = 9 to 12 years at T1) completed measures on 5 occasions across 2.5 years, using 6-month intervals. Random Intercept Cross-Lagged Panel Models were applied to disaggregate between- and within-person effects. RI-CLPMs analysis revealed that at the within-person level: (a) Childhood maltreatment and aggression bidirectionally predicted each other; (b) Childhood maltreatment and self-control bidirectionally predicted each other; (c) Aggression predicted subsequent self-control but not vice versa; (d) Childhood maltreatment did not indirectly predict aggression via self-control and vice versa; (e) Additionally, there were no gender differences observed in the longitudinal associations among childhood maltreatment, self-control and aggression. These findings advanced the literature by elucidating longitudinal associations among childhood maltreatment, self-control, and aggression at the within-person level, highlighting the significance of distinguishing between- and within-person effects in research informing the development of prevention and intervention programs aimed at reducing adolescent aggression.

Optical laser head is a key component used to shape the laser beam and to deliver higher power laser irradiation onto workpieces for material processing. A focused laser beam size and optical intensity need to be controlled to avoid decreasing beam quality and loss of intensity in laser material processing. This paper reports the multiphysics modeling of an in-house developed laser head for laser-aided additive manufacturing (LAAM) applications. The design of computer experiments (DoCE) combined with the response surface model was used as an efficient design approach to optimize the optical performance of a high power LAAM head. A coupled structural-thermal-optical-performance (STOP) model was developed to evaluate the influence of thermal effects on the optical performance. A number of experiments with different laser powers, laser beam focal plane positions, and environmental settings were designed and simulated using the STOP model for sensitivity analysis. The response models of the optical performance were constructed using DoCE and regression analysis. Based on the response models, optimal design settings were predicted and validated with the simulations. The results show that the proposed design approach is effective in obtaining optimal solutions for optical performance of the laser head in LAAM. Published version

The vital functions of long non‑coding (lnc)RNAs have been verified in gastric carcinoma (GC). However, as a novel cancer‑related lncRNA, the influence of leukemia inhibitory factor receptor antisense RNA 1 (LIFR‑AS1) in GC cell biological behaviors remains unreported. The present study explored the biological effects of lncRNA LIFR‑AS1 on GC progression. Reverse transcription‑quantitative PCR was performed to examine lncRNA LIFR‑AS1 expression in GC tissues and cells. Cell Counting Kit‑8, 5‑ethynyl‑2'‑deoxyuridine incorporation, cell wound healing and Transwell invasion assays were used to assess the functions of lncRNA LIFR‑AS1 in GC cell proliferation, migration and invasion. Additionally, associations among lncRNA LIFR‑AS1, microRNA (miR)‑4698 and microtubule‑associated tumor suppressor 1 (MTUS1) were investigated via bioinformatics software and a luciferase reporter system. In addition, western blotting was used to examine the expression of MEK and ERK. Decreased lncRNA LIFR‑AS1 expression was observed in GC tissues and cells. Upregulated lncRNA LIFR‑AS1 inhibited GC cell proliferation, migration and invasion. Upregulated miR‑4698 and downregulated MTUS1 were identified in GC tissues and cells. The inhibitory interaction between lncRNA LIFR‑AS1 and miR‑4698 was confirmed. Additionally, MTUS1 was predicted as a target gene of miR‑4698 positively regulated by lncRNA LIFR‑AS1. The MEK/ERK pathway was inhibited by lncRNA LIFR‑AS1 via regulating MTUS1. These findings revealed the inhibitory functions of lncRNA LIFR‑AS1 in GC cell proliferation, migration and invasion. The process was mediated via miR‑4698, MTUS1 and the MEK/ERK pathway.

In modern data storage systems, multiple disk drives arrays are densely located within a chassis or rack. Meanwhile, the chassis houses power suppliers, cooling fans, PCBs and switch boards too. During operation, mechanical disturbances from disk drive arm rotary motions, cross-talks between disk drives and cooling fans can generate adversely influence on a data storage system performance. In particular, the voice coil motor (VCM) torque induced by disk drive seeking operation affects not only its own but also neighbouring drives in terms of hard disk drive (HDD) throughput performance. Vibration analysis plays an important role in chassis system design for robustness which can mitigate the mechanical vibrations impact on disk drive throughput performances. In this paper, we report a finite element simulation based approach to predict vibration responses of the storage system chassis excited by operating disk drives and cooling fans. The purpose is to provide an effective vibration prediction analysis method that could aid in evaluating system-level vibration characteristics for chassis designers. An analytical model is described to formulate disk drive vibration behaviours in terms of design parameters. A full finite element model including the whole chassis structure, HDDs and its mounting mechanism components, storage controller boards and backplane board is constructed for simulation study. The mechanical disturbances are characterised by measuring VCM torque spectrums and fan operational vibration behaviours. HDD vibration responses at system-level are computed and well compared with the measurement results.

The measurement of power line spike interference sensitivity is an important item of EMC test. In this paper, the focus of the item and the principle of measurement are described. Combined with the engineering practice of cs06 project, a new way to solve the peak pulse interference of power line is given.

International audience; AbstractKey messageFresh litter contains a higher concentration of dissolved phosphorus (DP) than dissolved nitrogen (DN), which implies a more efficient DN transformation or reabsorption in the subalpine forest on the eastern Tibetan Plateau. Both DN and DP concentrations increased with the increase of mean monthly temperature, although the concentrations were also regulated by plant organs and species.ContextThe dissolved nitrogen (DN) and dissolved phosphorus (DP) released from fresh litter are important pathways by which total nitrogen and phosphorus are transferred from the vegetation to soil in forest ecosystems. However, few studies have paid attention to the DN and DP in fresh litter, which affects our understanding of the nitrogen and phosphorus cycles.AimsThe objectives of this study were to elucidate the dynamic characteristics of the concentrations and storage of DN and DP, and to analyze how DN and DP are affected by different plant species and organs, and climate factors.MethodsFresh litter was collected in three plots in a spruce-fir forest and classified by different plant species and organs. Concentration and storage of DN and DP in fresh litter were determined and related to the climatic variables that were monthly recorded.ResultsThe concentration of DP was higher than that of DN in fresh litter, and the concentrations of both elements were determined by plant organs and species. Moreover, The DN and DP concentration was positively related to mean monthly temperature, while DN and DP storage was negatively correlated with mean monthly temperature and monthly precipitation. The storage of DN and DP was determined by litter biomass, which the order in litter from different plant organs was leaves>twigs>miscellaneous>flowers and fruits. The storage of DN and DP in leaves showed two peaks in April and October, but that in twigs and the miscellaneous showed only one peak in October.ConclusionOur results indicated that dissolved nitrogen (DN) is transferred and reabsorbed more than dissolved phosphorus (DP) before plant leaf senescence and other organs fall. Furthermore, DN and DP were associated with climate, plant organs and species in a subalpine forest on the eastern Tibetan Plateau.

Sulfide and hydroxide ions, acting as negative and positive feedback species of the oscillatory electro-oxidation of sulfide on a platinum disk, respectively, strongly affected the spatiotemporal dynamics of the process. Oscillations with both hidden N-shaped and N-shaped negative differential resistances were enhanced in both amplitude and potential range with increasing sulfide ion concentration, but weakened with increasing hydroxide ion concentration. The patterns in the N-shaped negative differential resistance oscillatory region changed from local pulses to global synchronous oscillations of sulfur deposition and dissolution with increasing sulfide ion concentration. However, as the hydroxide ion concentration increased, both the patterns and oscillations were suppressed and the pulse width also decreased. External resistance was another factor that caused complex oscillations and a novel pattern formation that was observed to be alternating between local pulses and synchronous oscillations of sulfur deposition and dissolution. A detailed analysis of the reaction mechanism and a model simulation provided a reasonable explanation of these phenomena and the dynamic features. This investigation further promoted analysis of the complex spatiotemporal dynamics of the sulfide electro-oxidation system and enriched the experimental results available in electrochemical systems. This research was helpful in the prediction and control of pattern formation processing through adjustment of the positive and negative feedbacks as well as spatial couplings.

A three-stage actuation control system is proposed to enable high servo bandwidth track-following and possibly for small skew angle actuation system of hard disk drives. It involves a voice coil motor actuator as a primary actuator and a PZT actuated milliactuator as a secondary actuator. Both of them have the first dominant resonance mode at 5 kHz and the milliactuator has 200 nm stroke. A thermal microactuator having 50 nm stroke is used as a third actuator for a high servo bandwidth. A control strategy with controller design method is proposed to meet the performance requirement of each actuator's control loop and the overall control system. More than 6 kHz servo bandwidth is achieved and 430 nm external vibration can be covered by the three-stage actuation system. Simulation and experimental results demonstrate the control performance of the three-stage closed-loop system.

As more and more companies become aware of the benefits of collecting and analyzing data, hiring employee with data analytics expertise is a key issue faced by HR practitioners. Although previous research empirically highlighted the differences of knowledge and skill requirements between big data (BD) and business intelligence (BI) in English-speaking countries, limited similar study is conducted in China. By analyzing and interpreting the topic modeling results with dataset extracted from online job recruitment website Zhaopin.com, this exploratory study reveals that (1) the demand for BD competencies is far bigger (nearly six times) than the demand for BI competencies in China job market; (2) for Chinese employer, hard skills, especially those advanced analytic and programming skills, are much emphasized when HR searching for qualified BD applicants; (3) given the large volume and unstructured nature of big data, BD investments are currently much more human-capital-intensive than BI projects are. Our findings not only enhance the understanding of similarities and differences in BI and BD areas of competency but also provide guidance for organizations to choose suitable HR decisions.

In the transpassive region of sulfide electro-oxidation on platinum, the system displayed different complex oscillations under potentiostatic control experiments: changing from quasiperiodic small oscillations to alternate modes between small and large amplitude oscillations for increasing applied voltages. In each period of the alternating-mode oscillations, the current density evolves from slightly decreasing steady state to small and large amplitude oscillations. Spatiotemporal patterns developed on the platinum disk were recorded with a CCD camera and range from breathing spots to alternating patterns between breathing spots and synchronous deposition/dissolution. Karhunen-Loeve decomposition (KLD) analysis of the experimental patterns showed that the twinkling patterns had multiple modes each with low percentage of energy, while the alternate patterns were mainly characterized by one dominant mode.

The dual-stage actuation system based on a newly developed slider-level thermal microactuator has been demonstrated to be able to achieve 6 kHz control bandwidth with 60 kHz sampling rate. This paper reports the saturation control for the thermal microactuator. The aim is to release the thermal microactuator from saturation as soon as possible once the saturation occurs, and to maintain the system to be stable when the microactuator saturates. Typically, the antiwindup compensation scheme is used, due to its benefits of easy design and implementation as well as effectiveness for the thermal microactuator. Simulation and experimental testing shows the performance of this saturation control, when the dual-stage system undertakes a seeking task, especially a long distance seeking such as 40 and 80 nm seekings.

This paper is devoted to the control design and implementation of the dual-stage actuation system with a newly developed microthermal actuator (MTA) as the secondary actuator. The characterization and modeling of this new MTA is presented for controller design. Its performances such as stroke, time constant, and a good linearity are exhibited. The controller design of the MTA-based dual-stage actuation system is then proposed, and aims to push the bandwidth with the MTA. The simulation and the experimental testing have demonstrated the achievable 6-kHz bandwidth with 60-kHz sampling rate, the MTA displacement of 15 nm at 4 kHz, and 0.1-ms seeking time for 40-nm seeking length.

Spatiotemporal pattern formation in the electrocatalytic oxidation of sulfide on a platinum disk is investigated using electrochemical methods and a charge-coupled device (CCD) camera simultaneously. The system is characterized by different oscillatory regions spread over a wide potential range. An additional series resistor and a large electrode area facilitate observation of multiple regions of kinetic instabilities along the current/potential curve. Spatiotemporal patterns on the working electrode, such as fronts, pulses, spirals, twinkling eyes, labyrinthine stripes, and alternating synchronized deposition and dissolution, are observed at different operating conditions of series resistance and sweep rate.

Enterprise hard disk drives (HDDs) are widely used in high-end storage systems for data center. One of key performance requirements for enterprise HDDs is data access rate, which demands very high rotational speed (e.g. 15 k rpm or more) to permit fast access time. To reach such high speed, the disk spindle motor draws more power to spin and hence the temperature of HDD enclosure increases due to large windage loss. It has been known, temperature rise is one of the most fundamental factors that affect the reliability of the disk drive. In order to develop high reliable enterprise HDDs, thermal management of enterprise HDDs needs to be optimized to improve heat dissipation. One possible approach is to fill disk drive with helium because of its lower density and higher thermal conductivity. This paper investigates thermal performances of helium-filled enterprise disk drives through FEM simulations with experimental validations. Windage loss and heat convection of the HDD filled with helium and air are analysed. The simulated and measured temperature distributions of one commercial enterprise HDD with helium-filled and helium-air mixture are compared with those of an air-filled one. The results show 41% reduction of temperature rise of HDD enclosure can be achieved by filling with helium in comparison with that of air-filled HDD. It is also projected that in terms of equivalent cooling capability like air-filled HDD at 15 k rpm, helium-filled HDD spindle can spin up to 19 k rpm, which will greatly increase data access rate by 25% for future enterprise applications.

Due to the renowned superparamagnetic effect encountered in conventional magnetic data storage, many alternative futuristic data storage platforms have been proposed, e.g. Probe-Based Storage Systems (PBSS) successfully demonstrated in the ‘‘Millipede” project [Eletheriou E, Antonakopoulos T, Binning GK, Cherubini G, Despont M, Dholakia A, et al. Millipede—a MEMS-based scanning-probe data-storage system. IEEE Trans Magn 2003;39(2):938–45]. In this paper, a micro X–Y stage with 6 mm � 6 mm recording media platform actuated by capacitive comb drives is designed and fabricated in a so-called ‘‘Nanodrive” PBSS. The developed prototype is fabricated by micromachining techniques with the integration of a 40 nm thick PolyMethyl-MethAcrylate (PMMA) recording media. Using Finite Element Analysis (FEA) on the developed platform, the first two dominant in-plane resonant modes of the micro X–Y stage at 440 Hz are captured. A displacement range of up to 20lm can be achieved at an input driving voltage of 55 V. A Capacitive Self-Sensing Actuation (CSSA) circuit and robust decoupling control scheme are also designed for the micro X–Y stage for improved servo control. 2009 Published by Elsevier Ltd.

It is a big challenge to achieve recording density of 10 Tb/in2 for magnetic recording. Two promising technologies have been proposed for achieving density beyond 1 Tb/in2: heat assisted magnetic recording and bit patterned media. Owing to limitation of minimum media grain size or requirement of higher writing magnetic field, the densities of both technologies are still limited at below 5 Tb/in2. There is a need for new technology to push the density towards 5 Tb/in2 and beyond. Heat assisted bit patterned media recording is a good candidate to achieve this target. In this paper, thermal effects on bit patterned media at densities from 5 to 10 Tb/in2 are studied by numerical simulations. The results show that the media with soft under layer has bit mark vertical expansion of around 0.15 nm at 5 Tb/in2, which may cause recording performance change in the case of less than 3 nm space between magnetic write pole and recording layer. In order to obtain less than 1 ns cooling speed, a pulse heating method is proposed. With this method, the cooling speed gets tremendous improvement at BAR = 1 . Media with large BAR has worse thermal performances.

This paper reviews the recent developments in the area of MEMS-based probe recording technology. Various state-of-the-art scanning probe microscope (SPM) based techniques are briefly introduced, followed by the description of system approaches of MEMS-based probe recording technology and the basic MEMS-based actuation mechanism. Subsequently, current research status in developing MEMS-based probe recording technology with emphasis on storage architecture, MEMS access systems, probe recording mechanisms, and media for terabit per square inch recording density, is reviewed. Lastly, potential research topics and prospects for MEMS-based probe recording technology development are discussed.

In this paper, a single crystal silicon electrostatic microactuator for hard disk drives' (HDD) dual stage servo systems is presented. The microactuator is mounted between the slider and suspension and drives the slider on which a magnetic head element is attached. The microactuator has electrically isolated microstructures with an aspect ratio of 20:1 directly processed from a single crystal silicon substrate. It consists of a stator attached to the silicon substrate by a bus bar and a movable rotor connected to an anchored central column via spring beams. Both the stator and the rotor are suspended from the silicon substrate. Parallel plate capacitor pairs are used for the electrostatic actuation. When a voltage is applied to the microactuator, the head element will be driven to move in the tracking direction because of the rotational motion of the rotor. The microactuator prototype with overall dimensions 1.4 mm × 1.4 mm × 0.18 mm has been successfully fabricated. The techniques for integration of the microactuator with a head gimbal assembly (HGA) have been investigated. Experiments show that ±0.6 µm equivalent displacement of the head element in the tracking direction is achieved at the driving voltage 28.5 V. Dynamic frequency response testing of the microactuator bonded with the slider has been carried out. The test results demonstrate that the first in-plane resonance frequency of the electrostatic microactuator bonded with the slider is 1.9 kHz and the damping ratio is 2.8%, and the device is equivalent to a single spring mass system up to 50 kHz. The single crystal silicon electrostatic microactuator has a small mass, good thermal stability and dynamic performance, and is feasible to operate as a fine actuator in dual stage servo systems for high density HDD.

Electro-thermal actuations are very attractive since they can generate larger deflections and forces with low actuating voltages and their fabrication process is compatible with general IC fabrication process. In this paper, a novel micromirror actuated by four thermal bi-layer cantilevers is proposed as a fine-tracking device for high-density optical data storage. Each bi-layer cantilever comprises two material layers with different coefficients of thermal expansion. Due to bimorph effect, the cantilevers bend upwards and downwards an integrated micromirror in the out-of-plane direction. In the modeling of the thermal bi-layer cantilevers, mathematical models are built for both electro-thermal and thermal-mechanical analyses. Furthermore, finite element analysis is performed to evaluate the transient responses and thermal deformations under the actuating voltage and current. The simulation results show that the micromirror can be easily actuated more than 1.5 μm under 1 kHz 4v AC and the first mode resonance frequency is above 18 kHz. Finally, a fabrication process flow of the thermally actuated micromirror (TAM) is proposed. The proposed MEMS device also offers the potential for applications in adaptive optics systems and other optical systems.

Litterfall is the primary source of carbon and nutrients that determine soil fertility in forest ecosystems. Most current studies have focused on foliar litter, but the seasonal dynamics and allometric scaling relationships among different litter components (e.g., foliar litter, woody litter, reproductive litter, and epiphytic litter) are poorly understood. Here, we investigated the litter production of various litter components in a sub-alpine spruce-fir forest on the eastern Tibetan Plateau based on one year of observations (from August 2015 to July 2016). Our results showed that total litter production (LT) was 2380 kg·ha−1·year−1 (3% of the aboveground forest biomass), of which 73.6% was foliar litter (LF), 15.6% was woody litter (LW), 3.0% was reproductive litter (LR), 1.3% was epiphytic litter (LE), and 6.5% was miscellaneous material (LM). The total litterfall was bimodal (with peaks occurring in April and October) and was dominated by tree species (85.4% of LT, whereas shrubs accounted for 6.8% of LT). The litter production of evergreen species (68.4% of LT) was higher than that of deciduous species (23.8% of LT). Isometric relationships were observed between litter components and the total litter (i.e., LF∝LT0.99≈1 and LR∝LT0.98≈1), and allometric relationships were also found (i.e., LW∝LT1.40>1 and LM∝LT0.82

We report experimental results on the oscillatory electro-oxidation of thiosulfate on polycrystalline gold electrode in buffered media of pH 6.0. Importantly, we observed oscillations in the current density (potential) when the system was studied under linear sweep of potential (current density). The system displayed supercritical Hopf, period-doubling, homoclinic and bursting bifurcations at different applied currents and potentials. After presenting the dynamics under both potentiostatic and galvanostatic regimes, we characterized the system in terms of its electrical (ohmic drop compensation and electrochemical impedance spectroscopy) and chemical (Capillary Electrophoresis analysis) aspects. Ohmic resistance compensation and electrochemical impedance spectroscopy confirmed the hidden N-shaped negative differential resistance oscillatory character. Capillary electrophoresis analysis revealed the predominance of different oxidation products as a function of the applied potential. Finally, we suggest a tentative mechanism underlying the kinetic instabilities.

In this paper we present an approach to the layout and shape-optimization problem of bridge truss structures using genetic algorithms. The objective is to find an optimal layout design that will have minimum weight or material volume, subject to performance constraints related to member stresses, joint displacements, and member buckling. An automated two-stage optimization search process, which integrates structural analysis by finite-element method, genetic algorithms, and cognitive topology patterns (domain knowledge), is developed to solve the optimal problem. Two examples concerning bridge truss structure are investigated to demonstrate the effectiveness of the proposed method in solving these layout-optimization problems.

A new approach to optimization design concerning the configurations of structures using genetic algorithm (GA) with a tournament selection strategy has been proposed. The tournament selection strategy is used as a replacement for the commonly used fitness-proportional selection strategy to drive the GA so as to improve the fitness of each succeeding generation more efficiently. Numerical results for three examples reveal that a significant reduction of computation cost has been achieved in the newly proposed GA with tournament selection, as compared to the widely used GA with fitness-proportional selection and other hybrid GA approaches. Also, it has verified that the tournament selection performs well over the fitness-proportional selection and other hybrid techniques in enhancing GA search efficiency.

A photosensitive self-oscillating gel that incorporates the Belousov–Zhabotinsky reaction can undergo rhythmic mechanical oscillations. We exploit the dependence of the oscillation frequency on light intensity to generate both photophobic and phototropic movement of the gel under differential illumination. Our findings may be used in designing intelligent sensors that can execute biomimetic behaviours.

This paper reports a new rotary thermal micro-actuator. This new thermal actuator uses a pair of powerful silicon-polymeric composite benders to actuate a magnetic head slider into a rotation when the expandable polymer elements are resistively heated. The advantage is the rotary micro-actuator design can move the read/write head slider with a larger lateral displacement by using a new T-shape central hinge joint as compared to the previous translational design. The experimental results demonstrate that the prototyped device can reach up 314nm displacement by a 4V step voltage. The 1st mechanical resonance frequency has been pushed up to 35 kHz. Simulation shows that the micro-actuator can be subjected to 1000G shock loading under non-operation mode. The large displacement, high resonance frequency and robust shock resistance make the rotary thermal micro-actuator be very suitable for a wide range of precise positioning systems applications including dual-stage positioning systems in disk drives and resonance switches in microsystems.Copyright © 2013 by ASME

The adsorption of poisonous species on the catalyst surface impacts electrocatalytic reactions to different extents and by distinct means. The impact of adsorbing anionic species on electrocatalytic reactions has generally been investigated in the non-oscillatory regime or, at most, with temporal oscillations. Here, we report on spatiotemporal pattern formation in the electro-oxidation of sulfide on a platinum disk perturbed with dissolved chloride. The spatiotemporal dynamics was followed simultaneously with an electrochemical workstation and a charge-coupled device (CCD) camera. Perturbing the system with chloride results in (a) enhancement of dynamic instabilities throughout the current–potential curve, including regions of both positive and negative slope; (b) emergence of several spatial patterns; and (c) decreasing the width of pulses with increasing [Cl−]. The results are interpreted in terms of surface poisoning by chloride adsorption.

Recently, we have developed a polymeric composite electrothermal micro-actuator for dual-stage applications in hard disk drives (HDDs). The polymer composite was demonstrated with a larger thermal expansion as compared to silicon. Yet, the previous design of polymeric composite thermal actuator was stiff, having a high mechanical resonant frequency at 33 kHz and a moderate static displacement stroke of 50 nm at 4 V. An even larger stroke above 100 nm is generally required to meet the need of HDD dual-stage systems. To meet the requirement for a large stroke, we presented an improved design of polymeric composite electrothermal micro-actuator by increasing flexibility of the composite thermal benders. As compared to the previous design, the new design doubled the displacement stroke up to 106 nm at 4 V while it maintained a high mechanical resonant frequency of 31 kHz, slightly below that of the previous design. In addition, a finite element analysis showed that electrothermal activation of the micro-actuator is rather localized and it causes only a small temperature rise of the neighbouring parts of head gimbal assembly. These good performances suggested that this improved design of thermal micro-actuator is promising for high bandwidth dual-stage positioning systems in future high track density HDDs. ASTAR (Agency for Sci., Tech. and Research, S’pore) Accepted version

Shape design of a structure plays a significant part in deciding its least weight. In this paper, a fuzzy controlled genetic-based search technique for structural shape optimization is investigated. An automated optimal procedure based on the proposed approach is developed and used in the least-weight design of truss structures, which include their geometry as a design variable to be optimized. To increase the performance of the genetic-based approach for shape optimization problems, the design constraints related to member stress, joint displacement, and member buckling are described by using fuzzy set theory. A fuzzy rule-based system representing expert knowledge and experience is incorporated in the approach to control its optimal search process. Four examples for shape designs are presented to demonstrate the effectiveness and efficiency of the proposed hybrid approach in comparison with the use of pure genetic algorithms and other numerical methods. The examples show that the approach is flexible enough to deal with rigidly jointed structures.

Dynamic characteristics of a microactuator have been simulated using finite-element numerical analysis. Based on numerical simulations, the response surface method (RSM) is used to optimize the spring parameters for the determination of suitable in-plane and out-of-plane natural frequencies of vibrations. Optimization of designs resulted in reduced voltage supply requirement to drive the recording head, and the reliability of the microactuator has also been enhanced.

To predict the thrust force accurately in the design of linear micromotor, the Coulomb virtual work (CVW) method was applied to calculate the electromagnetic thrust force based on the finite-element solution of the electromagnetic field. Since only the magnetic field intensity H in the air layer surrounding the moving part is used to calculate the thrust force in the CVW method, the local errors of H in the sheath air layer severely affect the calculation accuracy. To reduce the considerable local errors of H in finite-element field solution, an estimation method of H error with an adaptive mesh algorithm was proposed. The proposed method can adaptively refine the mesh according to the evaluation of H error and thus increase the accuracy of force calculation effectively while require less computation time.