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Origami has various manifestations and rich production techniques, and it is regarded as one of the indispensable contemporary art forms. In order to enrich the creative expressions of fashion design, this paper summarises the creative application forms of origami art in fashion design from the external and moulding characteristics of origami, studies the fabric characteristics through experimental verification, and summarises the applicable techniques of expression. The results show that the folding application forms of origami art and clothing modelling can be realised by using the expression methods of ironing and crimping, stitching texture moulding and repeated combination moulding, that is, pattern deformation folding application, fabric transformation folding application and modular combination folding application. The application of the folding form in clothing three-dimensional modelling and surface texture can give full play to the unique modelling beauty and artistic style of origami art and provide a reference for creative ideas in clothing design.

Tetraploid cultivated cotton (Gossypium spp.) produces cottonseeds rich in protein and oil. Gossypol and related terpenoids, stored in the pigment glands of cottonseeds, are toxic to human beings and monogastric animals. However, a comprehensive understanding of the genetic basis of gossypol and gland formation is still lacking. We performed a comprehensive transcriptome analysis of four glanded versus two glandless tetraploid cultivars distributed in Gossypium hirsutum and Gossypium barbadense. A weighted gene co-expression network analysis (WGCNA) based on 431 common differentially expressed genes (DEGs) uncovered a candidate module that was strongly associated with the reduction in or disappearance of gossypol and pigment glands. Further, the co-expression network helped us to focus on 29 hub genes, which played key roles in the regulation of related genes in the candidate module. The present study contributes to our understanding of the genetic basis of gossypol and gland formation and serves as a rich potential source for breeding cotton cultivars with gossypol-rich plants and gossypol-free cottonseed, which is beneficial for improving food safety, environmental protection, and economic gains of tetraploid cultivated cotton.

The incorporation of a perfluoroalkyl group (RF) into drug candidates has become an increasingly important strategy in drug molecule design. In this study, the silver-mediated perfluoroalkylation reaction based on the addition-elimination process of terminal alkynes which was initiated by a perfluoroalkyl radical to form a C(sp)-RF bond has been developed. The reaction proceeds under mild conditions using readily available, low-cost perfluoroalkyl iodides as the sources of the RF group. This method allows access to a variety of perfluoroalkylated alkynes.

Implant-associated infections are generally difficult to cure owing to the bacterial antibiotic resistance which is attributed to the widespread usage of antibiotics. Given the global threat and increasing influence of antibiotic resistance, there is an urgent demand to explore novel antibacterial strategies other than using antibiotics. Recently, using a certain surface topography to provide a more persistent antibacterial solution attracts more and more attention. However, the clinical application of biomimetic nano-pillar array is not satisfactory, mainly because its antibacterial ability against Gram-positive strain is not good enough. Thus, the pillar array should be equipped with other antibacterial agents to fulfill the bacteriostatic and bactericidal requirements of clinical application. Here, we designed a novel model substrate which was a combination of periodic micro/nano-pillar array and TiO2 for basically understanding the topographical bacteriostatic effects of periodic micro/nano-pillar array and the photocatalytic bactericidal activity of TiO2. Such innovation may potentially exert the synergistic effects by integrating the persistent topographical antibacterial activity and the non-invasive X-ray induced photocatalytic antibacterial property of TiO2 to combat against antibiotic-resistant implant-associated infections. First, to separately verify the topographical antibacterial activity of TiO2 periodic micro/nano-pillar array, we systematically investigated its effects on bacterial adhesion, growth, proliferation, and viability in the dark without involving the photocatalysis of TiO2. The pillar array with sub-micron motif size can significantly inhibit the adhesion, growth, and proliferation of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Such antibacterial ability is mainly attributed to a spatial confinement size-effect and limited contact area availability generated by the special topography of pillar array. Moreover, the pillar array is not lethal to S. aureus and E. coli in 24 h. Then, the X-ray induced photocatalytic antibacterial property of TiO2 periodic micro/nano-pillar array in vitro and in vivo will be systematically studied in a future work. This study could shed light on the direction of surface topography design for future medical implants to combat against antibiotic-resistant implant-associated infections without using antibiotics. Keywords: Titanium dioxide, Micro/nano-structured surface, Topographical bacteriostatic activity, Photocatalytic bactericidal property, Non-invasive treatment

It is of practical significance to prolong the service life of the silk screen plate used for screen printing by a simple method. To our knowledge, no attempt has been made to coat silk screen stencil film with polybenzimidazole (PBI) to improve its abrasion resistance against squeegee in order to prolong the service life of the silk screen plate. In this study, the synthesized PBI with 2,6-disubstituted benzimidazole structure was coated on the silk screen stencil film by solution casting, and its effect on the morphology, roughness and abrasion resistance of stencil film was investigated by scanning electron microscope, atomic force microscope and Taber abrasion tester. The abrasion resistance of the silk screen stencil films with 1 and 19 μm thick PBI coating is improved by 18.6% and 87.6% compared with that of pure stencil film, respectively. The stencil film undergoes two wear stages: the first stage with a larger mass loss is characterized by the wear of photosensitive film; and the second one with a relatively smaller mass loss is characterized by the wear of both photosensitive film and silk screen. The thickness of PBI coating has an important effect on the substrate strength and surface properties of films during the wear, thus resulting in changes in the abrasion resistance of stencil films. It shows that 8 μm thick PBI coating is enough to protect the stencil film from wear.

A copper-catalyzed one-pot perfluoroalkylation of alkynyl bromides and terminal alkynes has been disclosed, and the corresponding perfluoroalkylated alkynes could be attained in good to excellent yields. The new straightforward transformation shows high efficiency (0.01-0.5 mol % catalyst loading), broad substrate scope, and remarkable functional group tolerance and provides a facile approach for useful application in life and material sciences.

In this study, a facile surface treatment method was proposed to improve the abrasion resistance of photosensitive film for screen printing. Of the three silane coupling agents used in this study, ...

Downhole micro-flux control drilling technology can effectively solve drilling accidents, such as kick and loss in narrow density window drilling scenarios. Using a downhole annular flow measurement system to obtain real-time information of downhole annular flow is the core and foundation of downhole micro-flux control drilling technology. The research work of electromagnetic flowmeters in recent years creates a challenge for downhole annular flow measurement. This paper proposes a new method for an annular flow measurement system based on the electromagnetic induction principle. First, the annular flow measuring principle, the weight function, the density of virtual current, and the magnetic field of the annular flow electromagnetic measurement system are described. Second, the basic design of the annular flow electromagnetic measurement system is described. Third, model simulation and dynamic experiments on an annular flow electromagnetic measurement system are carried out. The simulation and experimental results show a linear relationship between the system output and the annular flow rate, and also verify the correctness of annular flow electromagnetic measurement theory.

Joint clearance and the uncertainty of geometric and physical parameters significantly influence the kinematic accuracy and dynamic response of space deployable mechanisms. Such mechanisms have been widely employed in astronautic missions to improve the capabilities of launchers. This paper proposes a methodology to investigate the kinematic accuracy and dynamic performance of space deployable mechanism with joint clearance while considering parameter uncertainty. The model of space deployable mechanism with a planar revolute joint is provided. With consideration of several uncertain parameters, the solving procedure of the dynamic equations is presented based on the Monte Carlo method. A case study is conducted to reveal the effect of parameter uncertainty on its kinematic accuracy and dynamic performance. The results indicate that parameter uncertainty should be considered to accurately evaluate the performance of long-term operating space deployable mechanisms, especially for such systems with clearance joints. According to the results, brief suggestions for design and evaluation of the mechanisms are provided.

Implant-associated infections are generally difficult to cure owing to the bacterial antibiotic resistance which is attributed to the widespread usage of antibiotics. Given the global threat and increasing influence of antibiotic resistance, there is an urgent demand to explore novel antibacterial strategies other than using antibiotics. Recently, using a certain surface topography to provide a more persistent antibacterial solution attracts more and more attention. However, the clinical application of biomimetic nano-pillar array is not satisfactory, mainly because its antibacterial ability against Gram-positive strain is not good enough. Thus, the pillar array should be equipped with other antibacterial agents to fulfill the bacteriostatic and bactericidal requirements of clinical application. Here, we designed a novel model substrate which was a combination of periodic micro/nano-pillar array and TiO2 for basically understanding the topographical bacteriostatic effects of periodic micro/nano-pillar array and the photocatalytic bactericidal activity of TiO2. Such innovation may potentially exert the synergistic effects by integrating the persistent topographical antibacterial activity and the non-invasive X-ray induced photocatalytic antibacterial property of TiO2 to combat against antibiotic-resistant implant-associated infections. First, to separately verify the topographical antibacterial activity of TiO2 periodic micro/nano-pillar array, we systematically investigated its effects on bacterial adhesion, growth, proliferation, and viability in the dark without involving the photocatalysis of TiO2. The pillar array with sub-micron motif size can significantly inhibit the adhesion, growth, and proliferation of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Such antibacterial ability is mainly attributed to a spatial confinement size-effect and limited contact area availability generated by the special topography of pillar array. Moreover, the pillar array is not lethal to S. aureus and E. coli in 24 h. Then, the X-ray induced photocatalytic antibacterial property of TiO2 periodic micro/nano-pillar array in vitro and in vivo will be systematically studied in a future work. This study could shed light on the direction of surface topography design for future medical implants to combat against antibiotic-resistant implant-associated infections without using antibiotics., Graphical abstract Image 1, Highlights • TiO2 periodic micro/nano-pillar array was fabricated by “photolithography + RF magnetron sputtering + thermal oxidation”. • It is a model substrate for investigating the topographical bacteriostatic and TiO2 photocatalytic bactericidal effects. • Systematically investigated its effects on bacterial adhesion, growth, proliferation, and viability in the dark. • Such antibacterial ability mainly attributes to a spatial confinement size-effect generated by the special topography. • Different from conventional topographical antibacterial surfaces, it was prepared with a bioactive biomaterial (TiO2).

The genus Nysius Dallas (1852) from Mongolian Plateau is reviewed. Eight species are now recognized. Nysius ericae groenlandicus (Zetterstedt, 1838), known previously from Inner Mongolia, is referred to Nysius ericae ericae (Schilling, 1829). The paramere, pygophore, sperm reservoir and spermatheca of recorded species are illustrated. The distributional records of Nysius ericae ericae and Nysius thymi thymi (Wolff, 1840) are corrected. Photographs of adults, updated distribution maps and key for all species in Mongolian Plateau are provided.

Purpose The purpose of this study is to deal largely with the influence of temperature variation on the measurement accuracy of transit-time ultrasonic flowmeter. Design/methodology/approach The causes of measurement error due to temperature are qualitatively and quantitatively analyzed, and a mathematical model is established. The experimental data are processed and analyzed, and the temperature compensation coefficient of flow measurement is obtained. Findings The experimental results show that the flow measurement results by temperature compensation are helpful in improving the measurement accuracy of the ultrasonic flowmeter. Practical implications This study has certain application value, which can provide theoretical support for the design of high-precision ultrasonic flowmeters and design guidance. Originality/value It is worth emphasizing that there are few research studies on the influence factors of temperature. This paper focuses on the influence of the temperature change on the flowmeter that is modeled, and the high precision flow parameter test system is designed based on the established model.

Ejectors can be used in Joule–Thomson (JT) cooling systems to create sub-atmospheric pressures and to recover expansion work, and thus achieve lower temperatures and higher system efficiencies. As the key components of ejector-equipped JT cryocoolers, ejectors and counter flow heat exchangers (CFHXs) have significant effects on the cryocooler performance. In order to optimize the cryocooler performance, a 1-D ejector model, a 1-D finite-element model of CFHXs and a cryocooler model are developed. Results show that the variation of the ejector entrainment ratio with the primary flow inlet temperature depends on the ejector operation modes. Two tubes-in-tube CFHXs are designed to realize heat recovery with a relatively low pressure drop along the low-pressure channel of the CFHXs. The performance of CFHX I determines the operating conditions of the ejector, and there is an optimal CFHX I length corresponding to the maximum system COP. Differing from CFHX I, the COP increases with the length of CFHX II. For the designed cryocooler with nitrogen as the working fluid, a cooling capacity of 10.89 W at 71.8 K and COP of 0.042 can be obtained, and the COP increases by 13.1% compared to the basic ideal JT cooling cycle with the same cold-end temperature.

The bistable compliant mechanism has been widely used in the field of micro-electromechanical systems, industrial lines, and daily necessities. Enhancing mechanism reliability is helpful to prolong product life and to reduce the maintenance costs of bistable compliant mechanisms. This paper proposes one method to evaluate the mechanism reliability of the bistable compliant mechanism considering degradation and uncertainties of the parameters. The new method can be subdivided as follows: first, the pseudo-rigid body model is used to calculate the motion precision of the mechanism. Second, by introducing the degradation of stiffness and the randomness of the bending line into the kinematic equations, the other equilibrium position can be calculated with respect to the service duration. Third, by using the health index to judge the status of the mechanism, a large sample of failure time is generated and processed by the Kaplan–Meier estimator to characterize the mechanism reliability of the bistable compliant mechanism. A case studied in this paper reveals the mechanism reliability of a typical bistable compliant mechanism under different health indices and provides clues for the reliability evaluation and performance improvement of bistable compliant mechanisms.

The prophenoloxidase (PPO) activation pathway and Toll pathway are two critical insect immune responses against microbial infection. Activation of these pathways is mediated by an extracellular serine protease cascade, which is negatively regulated by serpins. In this study, we found that the mRNA abundance of silkworm serpin-5 (BmSpn-5) increased dramatically in the fat body after bacterial infection. The expression level of antimicrobial peptides (AMPs), gloverin-3, cecropin-D and -E decreased in the silkworm larvae injected with recombinant BmSpn-5 protein. Meanwhile, the inhibition of beads melanization, systemic melanization and PPO activation by BmSpn-5 was also observed. By means of immunoaffinity purification and analysis by mass spectrometry, we identified that the silkworm clip domain serine proteases BmHP6 and BmSP21 form a complex with BmSpn-5, which suggests that BmHP6 and SP21 are the cognate proteases of BmSpn-5 and are essential in the serine protease cascade that activates the Toll and PPO pathways. Our study provides a comprehensive characterization of BmSpn-5 and sheds light on the multiple pathways leading to PPO activation and their regulation by serpins.

A general and practical method for copper-catalyzed cross-coupling of allyl phosphates with stable perfluoroalkylzinc reagents has been developed. The reaction proceeds under mild reaction conditions with high efficiency, good functional group tolerance, and high regio- and stereoselectivities and provides general, straightforward, and useful access to allyl-perfluoroalkyl compounds. Preliminary mechanistic studies reveal that the allyl copper intermediate may be involved in the catalytic cycle.

Using the downhole annular flow measurement system to get real-time information of downhole annular flow is the core and foundation of downhole microflux control drilling technology. The research work of electromagnetic flowmeter in recent years creates a challenge to the design of downhole annular flow measurement. This paper proposes a design and optimization of annular flow electromagnetic measurement system for drilling engineering based on the finite element method. Firstly, the annular flow measuring and optimization principle are described. Secondly, a simulation model of an annular flow electromagnetic measurement system with two pairs of coil is built based on the fundamental equation of electromagnetic flowmeter by COMSOL. Thirdly, simulations of the structure of excitation system of the measurement system are carried out, and simulations of the size of the electrode’s radius are also carried out based on the optimized structure, and then all the simulation results are analyzed to evaluate the optimization effect based on the evaluation indexes. The simulation results show that optimized shapes of the excitation system and electrode size can yield a better performance in the annular flow measurement.

Dynamic characteristics of satellite separation are synthetical results of various influencing factors. However, there have been few quantitative investigations on impact evaluation of crucial parameters on dynamics of satellite separation. In this paper, an improved dynamic simulation model of the typical satellite separation system considering the flexibility of interface rings is established based on the authors׳ previous work. The dynamic-envelope radius of seventh V-segment and the shock response amplitude in horizontal section of SRS curves are, respectively, taken as evaluation index to perform the analyses of parameter sensitivity. Subsequently, an improved Response Surface Methodology (RSM) for analyzing parameter sensitivity of dynamics of satellite separation is proposed. Finally, the impact evaluations of different parameters are carried out, respectively, by performing the sensitivity analysis on dynamic-envelope of clamp band and satellite separation shock responses to determine the most important parameters that significantly influence the dynamic characteristics. It is revealed from the studies that the parameter which has the most prominent effect on the dynamic-envelope of clamp band is the stiffness of lateral-restraining spring. While for the axial and radial separation shock responses, the preload of clamp band and the density of V-segments are respectively the most influential parameters. The research results in the paper can provide a reference for the initial engineering design of the clamp band joint of satellite separation systems to guarantee a secure and reliable separation event.

Rigidly foldable origami tubes with open ends have been reported in the past. Here, using a mechanism construction process, we show that these tubes can be used as building blocks to form new tubes that are rigidly foldable with a single degree-of-freedom (SDOF). A combination process is introduced, together with a possibility of inserting new facets into an existing tube. The approach can be applied to both single and multilayered tubes with a straight or curved profile. Our work provides designers great flexibility in the design of tubular structures that require large shape change. The results can be readily utilized to build new structures for engineering applications ranging from deployable structures, meta-materials to origami robots.

At present, in domestic for the management of well control equipment continue to the traditional way of nameplates identifies and paper-based registration, there are many issues like the separation of data information of device, easy lose, difficult query, confused management and many other problems, which will make the problem device into the well field, and then resulting in well control runaway drilling accident. To solve the above problems, this paper put forward to the integrated remote centralized-monitoring management mode of the well-control equipment. Taking the advantages of IOT technology, adopting the RFID technology, and combining with the remote transmission, this paper designs the remote centralized-monitoring system of well-control equipment based on RFID, which realizes the intelligent management of well-control equipment and meets the actual demand of the well-control equipment safe use and timely scheduling, and it has the ability of field application.

Dynamic characteristics of satellite separation are synthetical results of various influencing factors. The improvement of research methods for designing and analyzing the separation system is of great importance for optimizing the dynamic performance of satellite separation. However, there is lack of an integrated approach for studying the satellite separation dynamics with full consideration of the attitude dynamics of satellites, the dynamic envelope of clamp band and the separation shock responses. This paper proposes a modeling and simulation method for comprehensively predicting the dynamic characteristics of satellite separation with the consideration of the flexibility of interface rings. A contrastive analysis of separation dynamics is carried out to determine the effects of the flexible interface rings on satellite separation dynamic characteristics. Subsequently, parametric studies on dynamics of satellite separation are performed, and research emphasis is placed on investigating the effects of position relative to the separation plane, the preload of clamp band, the friction coefficient and the pyroshock of explosive bolts on separation shock responses. The research method proposed in this paper provides a reference for the initial engineering design of the clamp band joint of satellite separation system.

Solar arrays are critical appendages that provide primary power sources for spacecrafts. This paper presents a numerical method to characterize the thermal response of a composite solar array subjected to space heat flux. Thermally induced vibration is investigated based on this method. The thermally induced vibrations of a solar array using two commonly used materials are also compared. Thermally induced vibrations in different thermal environments, incident angles of solar radiation, and material properties of honeycomb panel are discussed to reveal the causes of thermally induced vibration. Simulation results reveal the dynamic response of the solar array in low earth orbit under transient temperature, which could provide guidance for designers to optimize the structure utilized in minimizing the influence of the space thermal environment.

The improvement of methods for designing and analyzing separation systems is important for optimizing the dynamic performance of satellite separation, and for promoting the capacity of launch vehicles. This study presents the modeling and simulation methods of the clamp-band joint, which provide tools for designers to improve the clamp-band design, and therefore, the performance of the separation systems. The plate-element model is used to depict the clamp band, the nonlinear spring–damper model is used to describe the contact behavior between the V-segments of the interfaces, and a pyroshock model of the explosive bolt is developed. A multibody model is established using the Automatic Dynamic Analysis of Mechanical Systems software to simulate the satellite-separation process of a Long March 3B launch vehicle. The simulations are performed to illustrate the two-dimensional and three-dimensional envelopes of the clamp band, and the effects of critical factors on the dynamic envelope of the clamp-band join...

In order to improve the precision and efficiency of microelectronic bonding, this paper presents an improved adaptive genetic algorithm (IAGA) for the image segmentation and vision alignment of the solder joints in the microelectronic chips. The maximum between-cluster variance (OTSU) threshold segmentation method was adopted for the image segmentation of microchips, and the IAGA was introduced to the threshold segmentation considering the features of the images. The performance of the image segmentation was investigated by computational and experimental tests. The results show that the IAGA has faster convergence and better global optimality compared with standard genetic algorithm (SGA), and the quality of the segmented images becomes better by using the OTSU threshold segmentation method based on IAGA. On the basis of moment invariant approach, the microvision alignment was realized. Experiments were carried out to implement the microvision alignment of the solder joints in the microelectronic chips, and the results indicate that there are no alignment failures using the OTSU threshold segmentation method based on IAGA, which is superior to the OTSU method based on SGA in improving the precision and speed of the vision alignments.\ud

Nowadays, the harmonic drive is widely used as the reducer in the spacecraft manipulator, which may influence the dynamical properties of flexible spacecraft manipulator. The alternative thermal environment makes the spacecraft manipulator to experience periodic heating and cooling in the sunlight and shadow region of the Earth. The analysis of dynamic modeling and motion precision of flexible spacecraft manipulator with harmonic drive, considering the alternate thermal field in orbit is of significant importance for spacecraft manipulator designers in the early stage of design. The thermal load influences the motion precision, which reflects whether the mechanism is performed normally or not. In order to evaluate the loss of motion precision, this paper establishes the dynamical model of spacecraft manipulator with harmonic drive considering the alternate thermal field in orbit. A thermal analysis model of flexible spacecraft manipulator with harmonic drive is developed to characterize the thermal response of the whole spacecraft manipulator system subjected to space heat flux. Two different altitudes including low Earth orbit and geosynchronous Earth orbit are considered. Moreover, the transient temperature fields in different orbits of spacecraft manipulator and the effects of the thermal environment factors on the spacecraft manipulator are investigated. Simulation results reveal the evolution process of the transient temperature field of the spacecraft manipulator system. According to the results, the maximum temperature difference for space manipulator can lead to more severe precision loss compared with the minimum temperature difference. In addition, the vibration frequency of angular velocity error is determined by the maximum thermal heat flux. The proposed method is useful for forecasting the temperature distribution of the spacecraft manipulator system, and will provide meaningful information for performance enhancement of the aerospace facilities.

Rills are frequently observed on slope farmlands and rill erosion significantly contributes to sediment yields. This paper focuses on reviewing the various factors affecting rill erosion processes and the threshold conditions of rill initiation. Six factors, including rainfall, runoff, soil, topography, vegetation and tillage system, are discussed. Rill initiation and network are explored. Runoff erosivity and soil erodibility are recognized as two direct factors affecting rill erosion and other types of factors may have indirect influences on rill erosion through increasing or decreasing the effects of the direct factors. Certain conditions are necessary for rill initiation and the critical conditions are different with different factors. Future studies should be focused on 1) the dynamic changes of rill networks; 2) the combined effect of multiple factors; and 3) the relationships of threshold values with other related factors.

The morphing skin is the surface of a deployable frame which can change its shape to present optimal performance in all stages of a task for an aerospace vehicle. This article proposes a deployable frame with low kinematic error and high stability. Mechanical design and optimization of the deployable mechanism are developed, and specifically the analysis model of the deployable mechanism is established by the use of extendable units. The genetic algorithm is employed to find the optimal geometric parameters of the foldable structure. Furthermore, the design method of a bistable compliant mechanism is investigated to achieve the bistability. An example of a morphing leading edge (MLE) is analysed using the proposed method. The results show that the position errors converge to the optimal solution which supplies the minimum value. Numerical analysis indicates that the mechanism can provide two bistable positions for the actual use of the MLE.

Thermal analysis of the solar array is of great importance for the safe operation of spacecraft. In this paper, a thermal analysis model of composite solar array with complex structure is developed to characterize the thermal response of the whole solar array system subjected to space heat flux. Two different altitudes including low Earth orbit and geosynchronous orbit are discussed. The external heat flux of orbiting solar array in these orbits is proposed according to the flight attitudes. The thermal analysis model for the complex solar array is developed, in which all the honeycomb panel, simplified hinges, composite frames and yokes are taken into account. Moreover, the transient temperature fields in different orbits of all the components and the effects of the thermal environment factors on different components are discussed, and the thermal response of the solar array with two commonly used materials are contrastive analyzed. Simulation results reveal the evolution process of the transient temperature field of the whole solar array system. The proposed method is useful for forecasting the temperature distribution of the whole solar array system, and has important significance for the aerospace engineering.

This paper presents the mechanical design and experimental characterization of a 2-DOF serial flexurebased micropositioning table. The cascade mechanical structure is proposed to implement planar motions of the moving platform. In order to increase the stroke of the moving platform, a lever mechanism is designed to amplify the displacement of the piezoelectric actuator. The finite element method is utilized to analyze the mechanical and thermal characteristics of the proposed 2-DOF micropositioning table. The WEDM (Wire Electro-Discharge Machining) technique is used to manufacture the prototype of the micropositioning table. A number of experimental tests have been conducted to investigate the characteristics of the developed system. Design and Experimental Investigation of a 2-DOF Planar Micro-Positioning Table

Space deployable mechanisms have been widely employed in modern spacecraft, and the dynamic performance of such mechanisms has become increasingly important in the aerospace industry. This article focuses on the dynamic performance of a deployment mechanism with clearance considering damping, friction, gravity, and flexibility. The modeling methods of revolute joint with clearance, close cable loop, and lock mechanism of a typical deployable mechanism are provided in this article. Based on these proposed methods, the dynamics model of a space deployable mechanism with clearance is established using the multi-body program ADAMS. The effects of clearance, damping, friction, gravity, and flexibility on the dynamic performance of a deployable mechanism in the deploying and locking processes are studied using simulations. The results reveal that the deployable mechanism exhibits evidently nonlinear dynamic characteristics, thus validating the significance of clearance, damping, friction, gravity, and flexibility in system dynamic performance.

The paper presents numerical investigation of a novel counter-flow heat and mass exchanger used in the indirect evaporative dew point cooling systems, a potential alternative to the conventional mechanical compression air conditioning systems. Numeric simulation was carried out to optimise the geometrical sizes and operating conditions of the exchanger in order to enhance the cooling (dew point and wet bulb) effectiveness of the exchanger and maximise the energy efficiency of the dew point cooling system. The results of the simulations indicated that cooling (dew point and wet bulb) effectiveness and energy efficiency are largely dependent on the dimensions of the airflow passages, air velocity and working-to-intake-air ratio, and less dependent on the temperature of the feed water. It is recommended that exchanger intake air velocity should be controlled to a value below 0.3–0.5 m/s; height of air passage (channel) should be set to 6 mm or below and the length of the passage should be 200 time the height; the working-to-intake-air ratio should be around 0.4. Under the UK summer design condition, i.e., 28 °C of dry bulb temperature, 20 °C of wet bulb temperature and 16 °C of dew point temperature, the exchanger can achieve wet-bulb effectiveness of up to 1.3 and dew-point effectiveness of up to 0.9.

The ozophorine genus Vertomannus Distant, 1903 is reviewed in this paper. Ten species are recognized in the genus, including two new species, Vertomannus parvus sp. nov. and Vertomannus tibetanus sp. nov. The new species are described and illustrated. A key to all known members is included. Diagnosis of the genus, habitus photos, measurements, male genitalia illustrations, additional distributions are also presented.