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Designing ultrastrong near-infrared (NIR) absorbing organic semiconductors is a critical prerequisite for sensitive NIR thin film organic photodetectors (OPDs), especially in the region of beyond 900 nm, where the absorption coefficient of commercial single crystalline silicon (c-Si) is below 10

This paper describes a new type of hybrid fundamental solution based finite element method (HFS-FEM) for analysis of axisymmetric potential problems in multiply connected domain. In this approach, two independent potential fields are assumed within the element domain and on its boundary respectively. The fundamental solutions are utilized as internal trial functions to construct the non-conforming intra-element potential field. And the inter-element continuity is enforced by the conforming frame potential field which is of the same form as in the conventional FEM. Then, the axisymmetric modified variational functional is employed to derive the HFS finite element formulation. Finally, three numerical examples are given to demonstrate the validity, high-efficiency and robustness of the proposed method.

Background: Arabica coffee is a sub-tropical agricultural product in China. Coffee undergoes a series of thermal reactions to form abundant volatile profiles after roasting, so it loses a lot of reducing sugars and amino acids. Adding carbonyl compounds with amino acids before roasting could ensure the nutrition and flavour of coffee. The technology is versatile for the development of coffee roasting process. This investigation evaluates the effects of combining maltose and lysine (Lys) to modify coffee aroma and the possibly related mechanisms. Arabica coffee was pretreated with a series of solvent ratios of maltose and Lys with an identical concentration (0.25 mol L-1 ) before microwave heating.; Results: It was found that the combination of maltose and Lys significantly (P ≤ 0.05) influenced quality indices of coffee (pH and browning degree). Ninety-six aromatic volatiles have been isolated and identified. Twelve volatile profiles revealed the relationship between fragrance difference and compound content in coffee. Moreover, coffee aroma was modified by a large number of volatiles with different chemical classes and character.; Conclusion: Thus, our results suggest that the combination of reagents changed overall aroma quality through a series of complex thermal reactions, especially the ratio of Lys/maltose over 2:1. © 2017 Society of Chemical Industry.; © 2017 Society of Chemical Industry.

Umami is thought to be initiated by binding tastants to G-protein-coupled receptors in taste cells, while the structure and mechanism of the receptors are not clear. In this study, we summarized umami peptides and classified them roughly into two groups: the first group contains dipeptides and tripeptides with terminal Glu or Asp, while the second peptides comprises more amino acids without significant features. The research on the structure and taste characteristics of second group peptides are less studied, so we focus on this group. In this work, nine flavor peptides were newly identified from Takifugu obscurus, and among them, the umami hexapeptides KGRYER belong to the second group. Five hexapeptides from this study, our previous work and references were chosen to build a Three Dimensional Quantitative Structure-Activity Relationship model with q2 value as 0.964 successfully. Then the relationship between the structure and intensity of umami peptides were illustrated.

A planar coil - type MEMS driver is designed in this paper. The main structure consists of a top elastic platform and the bottom micro electromagnetic driving system. The upper platform is including cantilever beam, central platform and permanent magnet. The bottom micro electromagnetic driving system is including coil, substrate and energizing contact. The planar coil on the silicon substrate generates a magnetic field when it is energized, and the size of the electromagnetic force can be controlled by changing the current in the control coil. Therefore, the attractive elastic platform can overcome the elastic restoring force of the cantilever beam, and move to the bottom until contacting with the bottom. Because of a permanent magnet, the connection state will be maintained until a reverse current is applied to offset the magnetic effect and the driver returns to disconnection. Finally, the bi-stable control of the driver can be realized.

This work presents a novel method of reducing on-resistance (R on) in vertical double diffusion metal oxide semiconductor (VDMOS) devices using external stress. By electrodepositing a layer of nickel (Ni) film onto the surface of drain pad, intrinsic film stress is applied on the VDMOS chip. The experiment results show that R on was reduced by 1.7, 2.4, 4.5, 8.3 and 10.5% when the film stresses were 39.2, 49.3, 61.7, 71.6 and 80.3 MPa, respectively. Moreover, thermal stress between Ni film and VDMOS chip can further reduce R on when the temperature increases. Compared with conventional methods for R on reduction, this method is independent of fabrication process of VDMOS devices and capable of controlling accurately the applied stress.

This paper proposed the segmented magnetic circuit method to simulate the large displacement planar micro-coil (PMC) microactuator for micro-magnetic relay applications, which adopted enclosed miniaturized magnetic yokes. The segmented magnetic circuit model has been established to describe the magnetic flux variation and the redistribution effects of the magneto motive force (MMF) induced by the large air gap and large ratio between the radical and vertical size. Based on the optimized parameters, the PMC microactuator was fabricated through UV-LIGA technology and tested to verify the model under scrutiny. The large displacement was realized by using laminated photoresist sacrificial layer process. After comparing the measurement and simulation results, it is concluded that the modified model can describe the influence of key parameters over the output electromagnetic force. The proposed methodology is demonstrated to be efficient in the analysis and optimization of the magnetic MEMS devices of PMC structures with embedded magnetic yoke.

The low voltage switch has widely application especially in the hostile environment such as large vibration and shock conditions. In order to ensure the validity of the switch in the hostile environment, it is necessary to predict its mechanical characteristic. In traditional method, the complex and expensive testing system is build up to verify its validity. This paper presented a method based on finite element analysis to predict the dynamic mechanical characteristic of the switch by using ANSYS software. This simulation could provide the basis for the design and optimization of the switch to shorten the design process to improve the product efficiency.

Arabica coffee is a sub-tropical agricultural product in China. Coffee undergoes a series of thermal reactions to form abundant volatile profiles after roasting, so it loses a lot of reducing sugars and amino acids. Adding carbonyl compounds with amino acids before roasting could ensure the nutrition and flavour of coffee. The technology is versatile for the development of coffee roasting process. This investigation evaluates the effects of combining maltose and lysine (Lys) to modify coffee aroma and the possibly related mechanisms. Arabica coffee was pretreated with a series of solvent ratios of maltose and Lys with an identical concentration (0.25 mol LIt was found that the combination of maltose and Lys significantly (P ≤ 0.05) influenced quality indices of coffee (pH and browning degree). Ninety-six aromatic volatiles have been isolated and identified. Twelve volatile profiles revealed the relationship between fragrance difference and compound content in coffee. Moreover, coffee aroma was modified by a large number of volatiles with different chemical classes and character.Thus, our results suggest that the combination of reagents changed overall aroma quality through a series of complex thermal reactions, especially the ratio of Lys/maltose over 2:1. © 2017 Society of Chemical Industry.

This paper describes a new fabrication technology for high aspect ratio magnetic microstructures. These microstructures are made of composite magnetic materials. In this new technology, a master mold was made using photolithography and the mixture of magnetic particles and polymer was used in micro-molding process. The microstructures were then thermally cured at a temperature lower than 80 °C. To demonstrate the feasibility of using the technology in making magnetic microstructures, both hard magnetic and soft magnetic particles were tried in our experiments. The magnetic particle sizes ranged from 2.3 to 44 μm, which sets the limitations in feature sizes achievable for the magnetic microstructures. Different weight ratios were tried, the maximum weight ratio between the magnetic particle and the polymer was over 2:1. For both wall and trench microstructures, the maximum aspect ratio was found to be over 10, which demonstrates its great potential for micro-fabrication applications.

This article proposes a bistable electromagnetic micro-actuator consisting of a planar suspended platform and an integrated micro-coil, which was fabricated by micro-electromechanical systems technology. Its operational principle is based on the equilibrium between the magnetic force and elastic force. The elastic force of the suspended platform is analyzed by Castigliano's theorem, and the magnetic force is analyzed by the magnetic circuit method. Both the mechanical and magnetic characteristics were simulated by the finite-element method and verified by testing. Test results showed that the bistable electromagnetic micro-actuator could be realized at a voltage pulse of 5 V with 380 μm of large displacement, and the response time is about 4.96 ms.

This paper reports the design, fabrication and characterization of a bistable electromagnetic microrelay based on non-silicon surface micromachining technology. It mainly consists of an integrated microcoil at bottom with a spacer, and a suspension spring with a permanent magnet on top. Bistable mechanism is realized by the adoption of the SmCo permanent magnet to hold the microrelay at latching position without current. Switching between two stable states is completed by the variation of current direction in the microcoil. The corresponding power consumption is 25mJ. The fabrication processes of related components are presented. The test result shows that the bistable electromagnetic microrelay can work with low operation voltage pulse of 5V. The output displacement is about 380@mm while the response time is about 4.96ms. Besides, the test insertion loss is -0.02dB and the isolation is -39.91dB at 30MHz.

This paper reports the design, simulation and experimental study of a linear magnetic microactuator for portable electronic equipment and microsatellite high resolution remote sensing technology. The linear magnetic microactuator consists of a planar microcoil, a supporter and a microspring. Its bistable mechanism can be kept without current by external permanent magnetic force, and can be switched by the bidirectional electromagnetic force. The linearization and threshold of the bistable mechanism was optimized by topology structure design of the microspring. The linear microactuator was then fabricated based on non-silicon technology and the prototype was tested. The testing results indicated that the bistable mechanism was realized with a fast response of 0.96 ms, which verified the simulation and analysis.

This paper presents a bistable microswitch fully batch-fabricated on a single glass wafer, comprising of a microactuator, a signal transformer, a microspring and a permanent magnet. The bistable mechanism of the microswitch with large displacement of 160 μm depends on the balance of the magnetic force and elastic force. Both the magnetic force and elastic force were optimized by finite-element simulation to predict the reliable of the device. The prototype was fabricated and characterized. By utilizing thick laminated photoresist sacrificial layer, the large displacement was obtained to ensure the insulation of the microswitch. The testing results show that the microswitch realized the bistable mechanism at a 3–5 V input voltage and closed in 0.96 ms, which verified the simulation.

An electro-thermal SU-8 cantilever micro actuator with large vertical motion at low voltage is presented in this paper. It is lower in voltage due to employing SU-8 as functional material because of its high coefficient of thermal expansion. A finite element simulation was utilized to determine the optimal parameter. Windows in the center of cantilever can reduce internal residual stress. And we also added a nickel matrix on surface of support base to enhance bonding force between supportive base and driving section. Then actuators were obtained through Micro Fabrication Technology. Finally the Scanning-electron microscope and WYKO NT1100 optical profiling system demonstrated that the electro-thermal actuator possesses a high quality cantilever. Its stiffness is relative large that is sufficient for application in Micro device proved by Bonding Tester. With applied voltage 0.5V the electro-thermal actuator can generate a vertical displacement of 42.9μm.

In this paper, a new electroplating mask regarding deep etching on glass was revealed. It consisted of sputtered Chromium and Copper layer with electroplated Chromium and Gold layer, in combination with hard baked thick photoresist AZ4620 mask layer. After more than 3 hours' immerging in the HF etching solution, the etching depth attained more than 500μm. By using hard baking photoresist, the smoother surface was achieved. In addition, increasing the pattern width may help to reduce the undercut etching level and to accelerate the etching process. Compared with other masks in the literature, this new electroplating mask was simple, low cost and compatible with lithography technology, it can be widely used in MEMS applications.

With the development of the measurement techniques, especially the precision and ultra-precision measurement techniques, the measurement process of the geometric error based on the old GPS (geometrical product specification and verification) technology can hardly meet the requirement of high accuracy and efficiency. A new GPS system which was introduced by ISO/TC213 and based on metrology, has unified the whole process of product's specification and verification, and also realizes the digitized and standardized measurement. It provides a new approach to the measurement of the geometrical error by using the operation and operator technologies. In this paper the application of the operation technology in roundness error measurement is described in detail, moreover, the method and the key technique of realizing the process are also put forward. Lastly, by designing the appropriate verification operator of roundness error, the measurement process is specified and the measurement uncertainty is also decreased.

A topology variation method for the tuning of nonlinear vibration of planar spring was proposed and experimentally validated, which exhibited great potential for the application of energy harvesting by broadening the response bandwidth of the device. According to the numerical simulation and experimental results of all the three typical topological configurations, the topological scheme with inclined straight shape could provide the best nonlinearity. When this method was applied to the energy harvesting, the prototype device demonstrated a bandwidth of 28 Hz @180 Hz. It is concluded that the topological variation methodology could be efficient for the performance optimization of the energy harvester.

An electromagnetic bistable microactuator fabricated on a single wafer is presented. Its overall size is 3×3×1 mm. Tested results show that the bistable state of the device is realised by 5 V voltage pulse and held by the permanent magnet without current. The response time is 0.96 ms with a large displacement of 160 µm.