Showing papers by "Lei Wang published in 2014"

Gender Stereotypes of Personality Universal and Accurate

Abstract: Numerous studies have documented subtle but consistent sex differences in self-reports and observer-ratings of five-factor personality traits, and such effects were found to show well-defined developmental trajectories and remarkable similarity across nations. In contrast, very little is known about perceived gender differences in five-factor traits in spite of their potential implications for gender biases at the interpersonal and societal level. In particular, it is not clear how perceived gender differences in five-factor personality vary across age groups and national contexts and to what extent they accurately reflect assessed sex differences in personality. To address these questions, we analyzed responses from 3,323 individuals across 26 nations (mean age = 22.3 years, 31% male) who were asked to rate the five-factor personality traits of typical men or women in three age groups (adolescent, adult, and older adult) in their respective nations. Raters perceived women as slightly higher in openness, agreeableness, and conscientiousness as well as some aspects of extraversion and neuroticism. Perceived gender differences were fairly consistent across nations and target age groups and mapped closely onto assessed sex differences in self- and observer-rated personality. Associations between the average size of perceived gender differences and national variations in sociodemographic characteristics, value systems, or gender equality did not reach statistical significance. Findings contribute to our understanding of the underlying mechanisms of gender stereotypes of personality and suggest that perceptions of actual sex differences may play a more important role than culturally based gender roles and socialization processes.

Short-term effects of escitalopram on regional brain function in first-episode drug-naive patients with major depressive disorder assessed by resting-state functional magnetic resonance imaging.

Abstract: Background Most knowledge regarding the effects of antidepressant drugs is at the receptor level, distal from the nervous system effects that mediate their clinical efficacy. Using functional magnetic resonance imaging (fMRI), this study investigated the effects of escitalopram, a selective serotonin reuptake inhibitor (SSRI), on resting-state brain function in patients with major depressive disorder (MDD). Method Fourteen first-episode drug-naive MDD patients completed two fMRI scans before and after 8 weeks of escitalopram therapy. Scans were also acquired in 14 matched healthy subjects. Data were analyzed using the regional homogeneity (ReHo) approach. Results Compared to controls, MDD patients before treatment demonstrated decreased ReHo in the frontal (right superior frontal gyrus), temporal (left middle and right inferior temporal gyri), parietal (right precuneus) and occipital (left superior occipital gyrus and right cuneus) cortices, and increased ReHo in the left dorsal medial prefrontal gyrus and left anterior lobe of the cerebellum. Compared to the unmedicated state, ReHo in the patients after treatment was decreased in the left dorsal medial prefrontal gyrus, the right insula and the bilateral thalamus, and increased in the right superior frontal gyrus. Compared to controls, patients after treatment displayed a ReHo decrease in the right precuneus and a ReHo increase in the left anterior lobe of the cerebellum. Conclusions Successful treatment with escitalopram may be associated with modulation of resting-state brain activity in regions within the fronto-limbic circuit. This study provides new insight into the effects of antidepressants on functional brain systems in MDD.

Progress of the ITER Correction Coils in China

Abstract: The ITER Correction Coils (CC) include three sets of six coils each, distributed symmetrically around the tokamak to correct error fields. Each pair of coils, located on opposite sides of the tokamak, is series connected with polarity to produce asymmetric fields. The manufacturing of these superconducting coils is undergoing qualification of the main fabrication processes: winding into multiple pancakes, welding helium inlet/outlet on the conductor jacket, turn and ground insulation, vacuum pressure impregnation, inserting into an austenitic stainless steel case, enclosure welding, and assembling the terminal service box. It has been proceeding by an intense phase of R&D, trials tests, and final adjustment of the tooling. This paper mainly describes the progress in ASIPP for the CC manufacturing process before and on qualification phase and the status of corresponding equipment which are ordered or designed for each process. Some test results for the key component and procedure are also presented.

Epidemiological characteristics of motor neuron disease in Chinese patients

Abstract: Background The epidemiology, diagnosis, and treatment of motor neuron disease (MND) in Chinese patients are ill known. Methods A registered study of 461 MND patients was conducted across 10 facilities in 7 Chinese cities from February 2009 to March 2010. Results Patients were classified as amyotrophic lateral sclerosis (ALS) (84.4%), progressive bulbar palsy (PBP) (4.1%), progressive muscular atrophy (PMA) (10.4%), or primary lateral sclerosis (PLS) (0.9%). MND was predominant in men (men/women; 1.6:1.0). Mean onset age was 52.6 years, with the highest incidence being observed between 51 and 60 years. Notably, 26.0% of MND patients were employed in forestry, fishery, or animal husbandry industries. Ten cases (2.7%) reported family history of MND, and 54.2% exhibited cervical onset. MND was also associated with head/neck trauma. Non-invasive positive pressure ventilation was the most common supportive therapy. Conclusion As a novel comprehensive report of a Chinese population, this study reveals that epidemiological characteristics of MND patients were similar to those observed in international populations. MND is age-related, male gender predominant, and may be associated with both environmental and genetic risk factors.

KOAc-promoted alkynylation of α-C-H bonds of ethers with alkynyl bromides under transition-metal-free conditions.

Abstract: A novel KOAc-promoted α-position C–H activation and alkynylation of ethers with alkynyl bromides to 2-alkynyl ethers has been developed under transition-metal-free and simple reaction conditions. In addition, this methodology can also be extended to the vinylation of ethers with vinyl bromides in excellent regio- and stereo-selectivity. A wide range of direct C(sp)–C(sp3) and C(sp2)–C(sp3) bonds has been formed through this protocol, which offers a new and alternative route.

Dinuclear NHC–palladium complexes containing phosphine spacers: synthesis, X-ray structures and their catalytic activities towards the Hiyama coupling reaction

Abstract: Six dinuclear N-heterocyclic carbene (NHC) palladium complexes, [PdCl2(IMes)]2(μ-dppe) (1), [PdCl2(IPr)]2(μ-dppe) (2), [PdCl2(IMes)]2(μ-dppb) (3), [PdCl2(IPr)]2(μ-dppb) (4), [PdCl2(IMes)]2(μ-dpph) (5), and [PdCl2(IPr)]2(μ-dpph) (6) [IMes = N,N′-bis-(2,4,6-trimethylphenyl)imidazol-2-ylidene; IPr = N,N′-bis-(2,6-di(iso-propyl)phenyl)imidazol-2-ylidene; dppe = 1,2-bis(diphenylphosphino)ethane, dppb = 1,4-bis(diphenylphosphino)butane; and dpph = 1,6-bis(diphenylphosphino)hexane], have been synthesized through bridge-cleavage reactions of chloro-bridged dimeric compounds, [Pd(μ-Cl)(Cl)(NHC)]2, with the corresponding diphosphine ligands. The obtained compounds were fully characterized by 1H NMR, 13C NMR and 31P NMR spectroscopy, FT-IR, elemental analysis and single-crystal X-ray crystallography. Moreover, further explorations of the catalytic potential of the dinuclear carbene palladium complexes as catalysts for the Pd-catalyzed transformations have been performed under microwave irradiation conditions, and the complexes exhibited moderate to good catalytic activity in the Hiyama coupling reaction of trimethoxyphenylsilane with aryl chlorides.

Levels of neuropeptide Y in synovial fluid relate to pain in patients with knee osteoarthritis

Abstract: The precise etiology of knee osteoarthritis (KOA) pain remains highly controversial and there is no known effective treatment. Due to the known and suggested effects of neuropeptide Y (NPY) on pain, we have sought to investigate the relationship between the concentration of NPY in synovial fluid of knee, pain of KOA, and structural severity of KOA. One hundred KOA patients and twenty healthy participants (control group) were recruited. The pain and the radiographic grade of KOA were assessed separately by Hideo Watanabe’s pain score and Tomihisa Koshino’s scoring system. Synovial fluid of knee from all participants was collected with arthrocentesis. Radioimmunoassay was used to examine the concentration of NPY in synovial fluid of knee. Concentrations of NPY in synovial fluid were significantly higher in KOA patients (124.7 ± 33.4 pg/mL) compared with controls (64.8 ± 26.3 pg/mL) (p = 0.0297). According to Hideo Watanabe’s pain score, 100 KOA patients were divided into 5 subgroups: no pain (n = 12), mild pain (n = 25), moderate pain (n = 37), strong pain (n = 19) and severe pain (n = 7). Within the KOA group, significantly higher concentrations of NPY were found in each subgroup as pain intensified (no pain 81.4 ± 11.7 pg/mL, mild pain 99.1 ± 23.2 pg/mL, moderate pain 119.9 ± 31.5 pg/mL, strong pain 171.2 ± 37.3 pg/mL and severe pain 197.3 ± 41.9 pg/mL). Meanwhile, according to Tomihisa Koshino’s scoring system, 100 KOA patients were divided into 3 subgroups: early stage (n = 30), middle stage (n = 53), advanced stage (n = 17). Concentrations of NPY in middle and advanced stage groups of KOA patients were significant higher than early stage group of KOA patients (early stage 96.4 ± 27.1 pg/mL, middle stage 153.3 ± 16.9 pg/mL, advanced stage 149.5 ± 36.7 pg/mL) (p = 0.0163, p = 0.0352). Concentrations of NPY in advanced stage group of KOA patients has no significant difference compare with middle stage group of KOA patients (p = 0. 2175). This study demonstrated the presence and variation of concentrations of NPY in the KOA joint fluid, suggesting a role for NPY as a putative regulator of pain transmission and perception in KOA pain.

A four-culture study of self-enhancement and adjustment using the social relations model: do alternative conceptualizations and indices make a difference?

Abstract: In the self-enhancement literature, 2 major controversies remain--whether self-enhancement is a cultural universal and whether it is healthy or maladaptive. Use of the social relations model (SRM; Kenny, 1994) might facilitate resolution of these controversies. We applied the SRM with a round-robin design in both friend and family contexts in 4 diverse cultures: the United States (n = 399), Mexico (n = 413), Venezuela (n = 290), and China (n = 222). Results obtained with social comparison, self-insight, and SRM conceptualizations and indices of self-enhancement were compared for both agentic traits (i.e., egoistic bias) and communal traits (i.e., moralistic bias). Conclusions regarding cultural differences in the prevalence of self-enhancement vs. self-effacement tendencies, and the relationship between self-enhancement and adjustment, varied depending on the index of self-enhancement used. For example, consistent with cultural psychology perspectives, Chinese showed a greater tendency to self-efface than self-enhance using social comparison and self-insight indices, particularly on communal traits in the friend context. However, no cultural differences were observed when perceiver and target effects were controlled using the SRM indices. In all cultures, self-enhancement indices were moderately consistent across friend and family contexts, suggesting traitlike tendencies. To a similar extent in all 4 cultures, self-enhancement tendencies, as measured by the SRM indices, were moderately related to self-rated adjustment, but unrelated, or less so, to observer-rated adjustment.

A new library of arsine, stibine-stabilized N-heterocyclic carbene palladium complexes: synthesis, structures and activities in C-C and C-N coupling reactions.

Abstract: A series of new N-heterocyclic carbene palladium complexes bearing AsPh3 and SbPh3 functions PdCl2(IMes)(AsPh3) (1a), PdCl2(IMes)(SbPh3) (1b), PdCl2(IPr)(AsPh3) (1c), PdCl2(IPr)(SbPh3) (1d), PdCl2(SIMes)(AsPh3) (2a), PdCl2(SIMes)(SbPh3) (2b), PdCl2(SIPr)(AsPh3) (2c), and PdCl2(SIPr)(SbPh3) (2d) (IMes = N,N′-bis-(2,4,6-trimethylphenyl)imidazol-2-ylidene; IPr = N,N′-bis-(2,6-di(iso-propyl)phenyl)imidazol-2-ylidene; SIMes = N,N′-bis-(2,4,6-trimethylphenyl)imidazolidin-2-ylidene; SIPr = N,N′-bis-(2,6-di(iso-propyl)phenyl)imidazolidin-2-ylidene) was synthesized and fully characterized by 1H NMR, 13C NMR, and FT-IR spectroscopy, elemental analysis and single-crystal X-ray crystallography. The catalytic potential of these arsine and stibine-stabilized carbene palladium complexes for Pd-mediated transformations was investigated with various substrates in the Hiyama cross-coupling reactions and Buchwald–Hartwig aminations. The results demonstrate that these complexes show high catalytic activity and good tolerance to various chemical functions.

Effects of different gap filling methods and land surface energy balance closure on annual net ecosystem exchange in a semiarid area of China

Abstract: Based on eddy covariance measurements over two kinds of land surfaces (a degraded grassland and a maize cropland) in a semiarid area of China in 2005 and 2008, the effects of different gap filling methods, energy balance closure and friction velocity threshold (u*) on annual net ecosystem exchange (NEE) were analyzed. Six gap filling methods, including mean diurnal variation (MDV), marginal distribution sampling (MDS), and nonlinear regressions method, were investigated by generating secondary datasets with four different artificial gap lengths (ranging in length from single half-hours to 12 consecutive days). The MDS generally showed a good overall performance especially for long gaps, with an annual sum bias error less than 5 g C m−2 yr−1. There was a large positive annual sum bias error for nonlinear regressions, indicating an overestimate on net ecosystem respiration. The offset in the annual sum NEE for four nonlinear regressions was from 8.0 to 30.8 g C m−2 yr−1. As soil water content was a limiting factor in the semiarid area, the nonlinear regressions considering both soil temperature and soil water content as controlling variables had a better performance than others. The performance of MDV was better in daytime than in nighttime, with an annual sum bias error falling between −2.6 and −13.4 g C m−2 yr−1. Overall, the accuracy of the gap filling method was dependent on the type of the land surface, gap length, and the time of day when the data gap occurred. The energy balance ratio for the two ecosystems was nearly 80%. Turbulent intensity had a large impact on energy balance ratio. Low energy balance ratio was observed under low friction velocity during the night. When there was a large fetch distance in a wind direction, a low energy balance ratio was caused by mismatch of the footprints between the available energy and turbulent fluxes. The effect of energy balance correction on CO2 flux was evaluated by assuming the imbalance caused by the underestimation of sensible heat flux and latent heat flux. The results showed an average increase of 10 g C m−2 yr−1 for annual NEE in both ecosystems with an energy balance correction. On the other hand, the u* threshold also have a large impact on annual sum NEE. Net carbon emission increased 37.5 g C m−2 yr−1 as u* threshold increased from 0.1 to 0.2 m s−1, indicating a large impact of imposing u* threshold on net ecosystem carbon exchange.

An energy based regression method to evaluate critical CTOA of pipeline steels by instrumented drop weight tear tests

Abstract: An energy based regression method to estimate critical crack-tip-opening-angle (\(\hbox {CTOA}_\mathrm{C}\)) of high strength and toughness pipeline steels has been established derived from the Martinelli-Venzi ductile fracture model. Key curve method was applied onto the load-displacement curves of standard pressed-notch drop-weight-tear-test specimens to evaluate the dynamic crack extension, providing a way to verify the correlation between the load and remaining ligament width. In the meanwhile, the material based parameter (\(\hbox {A}^{*} \upsigma _\mathrm{f}\)), usually required by other \(\hbox {CTOA}_\mathrm{C}\) estimation algorithm, could also be determined experimentally. As a result, \(\hbox {CTOA}_\mathrm{C}\) of a typical high grade pipeline steel plate was acquired as a constant over steady-state stage during crack propagation, independent of specimen geometry.

Culture medium for induced pluripotent stem cells and application of culture medium

Abstract: The invention provides a culture medium for culturing induced pluripotent stem cells. The culture medium contains a ginsenoside monomer Rb1, a ginsenoside monomer Rb3 and/or a ginsenoside monomer Rd. The invention also provides a method for inducing pluripotent stem cells. The method comprises the following steps: (1) introducing pluripotent-related genes into donor cells; (2) preparing the donor cells in which the pluripotent-related genes are introduced into single-cell suspension, and culturing the donor cells (in which the pluripotent-related genes are introduced in the step (1)) by using the culture medium provided by the invention; and (3) identifying cloning of the pluripotent stem cells. In consideration of the application bottleneck of ips to clinical test at present, the ginsenoside monomer Rb1, the ginsenoside monomer Rb3 and the ginsenoside monomer Rd are discovered, the ips induction efficiency can be obviously improved, cell senescence can be obviously delayed, cell proliferation can be promoted, and far-reaching influence is generated in the entire field of stem cell research and new drug research and development.

Low sink-induced stomatal closure alters photosynthetic rates of source leaves in beans as dependent on H2O2 and ABA accumulation in guard cells

Abstract: Low sink demand provided by pod removal and stem girdling of beans (Vicia faba, cv. Daqingshan) (-Sink) induced a significantly lower net photosynthetic rate (P n), stomatal conductance (g s), internal CO2 concentration (C i), and transpiration rate (E) compared with pod and root sink retention (CK). This depression in P n was due to stomatal limitation. Low sink demand of -Sink plants resulted in a higher leaf sucrose content, but a lower sucrose content in guard cells. Moreover, the significant accumulation of H2O2 and ABA were observed in both leaves and guard cells of -Sink plants. The most intensive electron dense deposit of cerium perhydroxides, produced by H2O2 reaction with cerium chloride, was present in the cell walls, especially the dorsal walls of guard cells. Immunogold electron-microscopy localization of ABA showed that ABA was distributed in ventral walls of guard cells and the intercellular space of mesophyll cells of -Sink leaves in contrast to CK plants. Application of exogenous sucrose to isolated bean leaves increased H2O2 and ABA contents. H2O2 and ABA in leaves was likely generated by two independently regulated pathways, each affected by the high sucrose concentration induced by low sink demand. Increased sucrose in leaves in response to low sink demand may have caused the increase of H2O2 and ABA, and their accumulation in mesophyll cells and guard cells was likely the primary cause for stomatal closure under low sink demand.

Three-leg type magnetic field detection robot

Abstract: The invention discloses a three-leg type magnetic field detection robot which is composed of a supporting unit and three leg units. The supporting unit is formed by top plates and supports. The three leg units are evenly arranged on the periphery of the supporting unit, the included angle between connecting lines of any two leg units and the center of the supporting unit is 120 degrees, and the leg units are driven by stepping motors. According to the three-leg type magnetic field detection robot, three-leg vertical type walking and folding type walking can be achieved according to different working conditions.

Superconducting magnet winding stress overload protection device

Abstract: A superconducting magnet winding stress overload protection device consists of a base, two support units and one chute unit. The base is located at the bottommost end of the whole device, the support units are respectively installed at two ends of the base, and the chute unit is welded between the support units. A spring, a slide block and the like are installed in a chute and play a protective role. In the solenoid superconducting magnet winding process, certain uncontrollable mechanical disturbance causes superconducting wire stress overload, and accordingly a breakage accident of a superconducting wire occurs. The superconducting magnet winding stress overload protection device can play a superconducting wire protecting role when the superconducting wire is in a tensile stress overload state.

Levels of neuropeptide Y in synovial fluid relate to pain in patients with knee osteoarthritis

Abstract: The precise etiology of knee osteoarthritis (KOA) pain remains highly controversial and there is no known effective treatment. Due to the known and suggested effects of neuropeptide Y (NPY) on pain, we have sought to investigate the relationship between the concentration of NPY in synovial fluid of knee, pain of KOA, and structural severity of KOA. One hundred KOA patients and twenty healthy participants (control group) were recruited. The pain and the radiographic grade of KOA were assessed separately by Hideo Watanabe’s pain score and Tomihisa Koshino’s scoring system. Synovial fluid of knee from all participants was collected with arthrocentesis. Radioimmunoassay was used to examine the concentration of NPY in synovial fluid of knee. Concentrations of NPY in synovial fluid were significantly higher in KOA patients (124.7 ± 33.4 pg/mL) compared with controls (64.8 ± 26.3 pg/mL) (p = 0.0297). According to Hideo Watanabe’s pain score, 100 KOA patients were divided into 5 subgroups: no pain (n = 12), mild pain (n = 25), moderate pain (n = 37), strong pain (n = 19) and severe pain (n = 7). Within the KOA group, significantly higher concentrations of NPY were found in each subgroup as pain intensified (no pain 81.4 ± 11.7 pg/mL, mild pain 99.1 ± 23.2 pg/mL, moderate pain 119.9 ± 31.5 pg/mL, strong pain 171.2 ± 37.3 pg/mL and severe pain 197.3 ± 41.9 pg/mL). Meanwhile, according to Tomihisa Koshino’s scoring system, 100 KOA patients were divided into 3 subgroups: early stage (n = 30), middle stage (n = 53), advanced stage (n = 17). Concentrations of NPY in middle and advanced stage groups of KOA patients were significant higher than early stage group of KOA patients (early stage 96.4 ± 27.1 pg/mL, middle stage 153.3 ± 16.9 pg/mL, advanced stage 149.5 ± 36.7 pg/mL) (p = 0.0163, p = 0.0352). Concentrations of NPY in advanced stage group of KOA patients has no significant difference compare with middle stage group of KOA patients (p = 0. 2175). This study demonstrated the presence and variation of concentrations of NPY in the KOA joint fluid, suggesting a role for NPY as a putative regulator of pain transmission and perception in KOA pain.

Influence of electrostatic field treatment on microstructures and mechanical properties of GH4169 superalloy

Abstract: An external electrostatic field treatment (EFT) was applied to GH4169 alloy with standard heating treatment The internal friction and room temperature (RT) tensile test were conducted for both the electrostatic field treated and standard heating treated alloys in order to investigate the variations of microstructure and mechanical properties of the alloy with the EFT The experimental results demonstrated that the EFT remarkably enhanced the formation of interstitial atoms and vacancies During the tensile deformation at RT under the strain rate of 10−2 or 10−4 s−1, the dislocation slip could be evidently hindered by the large numbers of interstitial atoms in the matrix, contributing to a great increase in the yield and tensile strengths of the electrostatic field treated alloy By EFT, the dislocation configuration of deformed alloy was primarily the single slip instead of the cross-slip in the standard heating treated alloy, resulting in the increasing of grain deformation capacity by more vaca

Double-pump and four-jetting wefting insertion system for hydraulic loom

Abstract: The utility model relates to a double-pump and four-jetting wefting insertion system for a hydraulic loom. The double-pump and four-jetting wefting insertion system comprises a water storage tank, a weft yarn jetting mechanism, a weft yarn storage mechanism and a loom wefting insertion electronic control system. The double-pump and four-jetting wefting insertion system is characterized in that two water pumps are adopted in the weft yarn jetting mechanism so that the weft yarn jetting mechanism can jet water to two weft yarn sets (strips/sets) which are totally different in feature, two reversing valves of double pipelines are adopted, the loom electronic control system can control the reversing valves easily and conveniently, installation is simple, the number of water pipes is reduced, the cost is saved, and the shortcomings in the prior art are overcome.

Elevation type superconducting magnet conveying device

Abstract: Disclosed is an elevation type superconducting magnet conveying device. The elevation type superconducting magnet conveying device is composed of a frame unit, two lifting units and four wheel units. The frame unit is the basis of the entire conveying device, the two lifting units are arranged at the front end and the rear end inside the frame unit, and the four wheel units are arranged on the left side and the right side of a vehicle body and are mounted at the tail ends of the lifting units. Due to the fact that rotating shafts of the lifting units are rotated, the center of the gravity of the vehicle body can be lifted, the position of the vehicle body can be changed, and the wheel units are driven by a DC servo motor.

Grain size and grain boundary effects on hydrogen induced nanovoid nucleation in polycrystalline Ni

Abstract: A theoretical model was developed to study the effects of grain boundary (GB) structure and grain size on nucleation of nanovoid in the presence of hydrogen in polycrystalline Ni The nanovoid nucleation rate at low angle grain boundary (LAGB) increases with decreasing the grain size as well as increasing the hydrogen concentration The microstructure with high fraction of LAGBs shows the lower fraction of nanovoid, thus enhances the ductility and fracture toughness of materials

KOAc-Promoted Alkynylation of α-C—H Bonds of Ethers with Alkynyl Bromides under Transition-Metal-Free Conditions.

Abstract: A novel KOAc-promoted α-position C–H activation and alkynylation of ethers with alkynyl bromides to 2-alkynyl ethers has been developed under transition-metal-free and simple reaction conditions. In addition, this methodology can also be extended to the vinylation of ethers with vinyl bromides in excellent regio- and stereo-selectivity. A wide range of direct C(sp)–C(sp3) and C(sp2)–C(sp3) bonds has been formed through this protocol, which offers a new and alternative route.

Sustaining device for winding of superconducting magnet

Abstract: A sustaining device for winding of a superconducting magnet is composed of a base unit, an arm unit and a sustaining unit. The base unit is arranged at the bottommost end of the whole device and is the basis of the whole device. The arm unit is arranged above the base unit and has four degrees of freedom. The sustaining unit is mounted at the tail end of the arm unit and has one degree of freedom. The arm unit and the sustaining unit are both driven by a direct current servo motor.

Mechanical finger without exogenetic force

Abstract: Disclosed is a mechanical finger without an exogenetic force. The mechanical finger without the exogenetic force comprises a first knuckle (5), a second knuckle unit, a third knuckle (10) and a connecting rod unit (13), wherein the second knuckle unit is composed of an upper cover, a lower cover, a first shaft, a second shaft, a first gear wheel, a second gear wheel and a blocking plate, the connecting rod unit is composed of a first connecting rod, a second connecting rod and a third connecting rod, and the three knuckles are connected to form the whole mechanical finger. The motive force of the mechanical finger comes from changes of angles among the knuckles when the finger is bent, the changes of the angles drive the connecting rod unit, the first gear wheel and the second gear wheel, and then the gear wheels drive the third knuckle to move.

Study of the defect evolution of the GH4169 superalloy under electrostatic field

Abstract: An electrostatic field was applied to the GH4169 alloy during ageing, and the defect evolution process and mechanism were investigated using positron annihilation spectroscopy and vacuum inverted pendulum mechanical spectrometer. The results indicated that atomic thermal vibration and vacancy mobility can be increased by the electrostatic field treatment (EFT), resulting in the enhancement of vacancy formation. Under EFT, the relationship between atomic thermal vibration energy and the ageing temperature gives the E index, and there are more vacancies in the matrix with an increase in the ageing temperature. As the alloy was aged at 1073 K, the atomic thermal vibration energy displays the exponential growth with electric field intensity, contributing to an increase in the vacancy size and amount.

Effect of stabilisation on precipitation behaviour and mechanical properties of alloy GH4706

Abstract: Fe–Ni base superalloy GH4706 has been used for large size disc forgings of heavy duty gas turbines In this paper, based on the change law of precipitation, influential effects of stabilisation time on precipitation behaviour and mechanical properties of GH4706 alloy were investigated Results show that with prolongation of the stabilisation time, the morphologies of η phase changed from chain and rod-like to cellular, cluster and needle-shaped; meanwhile, large globular γ′ phase and rod-like γ″ phase gradually precipitated Furthermore, the content of the η phase increased with increasing stabilisation time, and the precipitation free zone tended to be wider, owing to the reaction between the γ′ phase and the η phase The room temperature and 650°C tensile strength and rupture life of the GH4706 alloy improved after stabilisation treatment at 845°C for 1–3 h

Animal model suffered from femoral head necrosis induced by hormone as well as construction method and device of animal model

Abstract: The invention provides an animal model suffered from femoral head necrosis induced by hormone as well as a construction method and a device of the animal model. The construction method of the animal model suffered from femoral head necrosis induced by hormone comprises the following steps of (1), taking a model animal, and injecting hormone in the model animal with the dosage of 2-49 mg/kg every week; (2), providing a raising cage with a raising tank having adjustable height, wherein the raising tank is used for containing feed and water; and (3), raising the animal injected with hormone in the step (1) in the raising cage provided in the step (2), adjusting the height of the raising tank in the raising cage simultaneously, so the lower limbs of the model animal are upright after feeding and drinking water, thereby obtaining the animal model suffered from femoral head necrosis induced by hormone after raising for 1-4 weeks.

Fatigue crack propagation behaviour of a nickel based superalloy at elevated temperatures

Abstract: The fatigue crack growth behaviour of a nickel based superalloy at elevated temperatures 550, 650 and 710°C was studied. The direct current potential drop (DCPD) technique was used to measure the crack length during the test. It was found that the crack growth rates slightly increased with increasing temperatures, but the temperature effect on crack growth rates was less pronounced at higher ΔK ranges. At the same temperature the crack growth rates increased with increasing load ratios. The oxidation induced crack closure is considered to be a reason of the observed crack growth behaviour in this study.