Parameters Sensitivity Characteristics of Highly Integrated Valve-Controlled Cylinder Force Control System

Nowadays, a highly integrated valve?controlled cylinder(HIVC) is applied to drive the joints of legged robots. Although the adoption of HIVC has resulted in high?performance robot control, the hydraulic force system still has problems, such as strong nonlinearity, and time?varying parameters. This makes HIVC force control very diffcult and complex. How to improve the control performance of the HIVC force control system and find the influence rule of the system parameters on the control performance is very significant. Firstly, the mathematical model of HIVC force control system is established. Then the mathematical expression for parameter sensitivity matrix is obtained by applying matrix sensitivity analysis(PSM). Then, aimed at the sinusoidal response under(three factors and three levels) working conditions, the simulation and the experiment are conducted. While the error between the simulation and experiment can’t be avoided. Therefore, combined with the range analysis, the error in the two performance indexes of sinusoidal response under the whole working condition is analyzed. Besides, the sensitivity variation pattern for each system parameter under the whole working condition is figured out. Then the two sensitivity indexes for the three system parameters, which are supply pressure, proportional gain and initial displacement of piston, are proved experimentally. The proposed method significantly reveals the sensitivity characteristics of HIVC force control system, which can make the contribution to improve the control performance.

Characterization and application in XRF of HfO_(2)-coated glass monocapillary based on atomic layer deposition

Coating a glass monocapillary x-ray optics with high-density film is a promising way to improve transmission characteristics. For a long time, it has been a challenge to coat a high-density film in the inside of monocapillary with an extremely high length-to-diameter ratio. In this work, Hf O2 film is deposited on the inner wall of a tapered glass monocapillary with length 9.9 cm, entrance diameter 596.4 μm, and exit diameter 402.3 μm by atomic layer deposition. The coated and uncoated monocapillaries are studied by the transmission process of x-rays with energy from 5 ke V to 100 ke V and the x-ray fluorescence(XRF) spectra of a Mo sample are detected. Improved transmission characteristics have been obtained for the Hf O2-coated monocapillary. The energy upper limit of focused x-rays increases from 18.1 ke V to 33.0 ke V and the ‘penetration halo’ is suppressed to some extent. The XRF spectrum presents two stronger peaks at ~ 17.4 ke V and~ 19.6 ke V which are considered as the characteristic x-rays of Mo Kα and Mo Kβ. These results reveal that more higher energy x-rays from the W x-ray tube are totally reflected on the inner wall of the Hf O2-coated glass monocapillary due to the increase of total reflection critical angle. This work is significant for more applications of monocapillary in higher energy x-ray field.

Nerve Growth Factor for the Treatment of Spinocerebellar Ataxia Type 3： An Open-label Study

Background： Spinocerebellar ataxia type 3 （SCA3） is the most common subtype of SCA worldwide, and runs a slowly progressive and unremitting disease course. There is currently no curable treatment available. Growing evidence has suggested that nerve growth factor （NGF） may have therapeutic effects in neurodegenerative diseases, and possibly also in SCA3. The objective of this study was to test the efficacy of NGF in SCA3 patients. Methods： We performed an open-label prospective study in genetically confirmed adult （〉18 years old） SCA3 patients. NGF was administered by intramuscular injection （18 μg once daily） fbr 28 days consecutively. All the patients were evaluated at baseline and 2 and 4 weeks after treatment using the Chinese version of the scale for assessment and rating of ataxia （SARA）. Results： Twenty-one SCA3 patients （ 10 men and 11 women, mean age 39.14 ± 7.81 years, mean disease duration 4.14 ± 1.90 years, mean CAG repeats number 77,57 ± 2.27） were enrolled. After 28 days of NGF treatment, the mean total SARA score decreased significantly from a baseline of 8.48± 2.40 to 6.30 ± 1.87 （P 〈 0.001 ）. Subsections SARA scores also showed significant improvements in stance （P = 0.003）, speech （P = 0.023）, finger chase （P = 0.015）, fast alternating hand movements （P = 0.009）, and heel-shin slide （P = 0.001）. Conclusions： Our preliminary data suggest that NGF may be effective in treating patients with SCA3.

Effect of silk sericin on morphology and structure of calcium carbonate crystal

In this paper, silk sericin was employed to regulate the mineralization of calcium carbonate （CaC03）. CaCO3 composite particles were prepared by the precipita- tion reaction of sodium carbonate with calcium chloride solution in the presence of silk sericin. The as-prepared samples were collected at different reaction time to study the crystallization process of CaCO3 by scanning electron microscopy （SEM）, Fourier transform infrared spectroscopy （FTIR）, thermogravimetric analysis （TGA） and X-ray diffraction （XRD）. The results showed that silk sericin significantly affected the morphology and crystallographic polymorph of CaCO3. With increasing the reaction time, the crystal phase of CaCO3 transferred from calcite dominated to vaterite dominated mixtures, while the morphology of CaCO3 changed from disk-like calcite crystal to spherical vaterite crystal. These studies showed the potential of silk sericin used as a template molecule to control the growth of inorganic crystal.

Neutron diffraction studies of permanent magnetic materials

Neutron diffraction technology as an advanced material research technique has special advantages in studying magnetic materials compared to the conventional techniques such as X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),and X-ray photoelectron spectroscopy(XPS).In this review,the applications of neutron diffraction technology on permanent magnetic materials were briefly reviewed:(1)the determination of the crystal structure and magnetic structure of the typical permanent magnet material,(2)in situ neutron diffraction study of the crystal structure evolution of the permanent magnets,and(3)phase transition in permanent magnetic materials.

Tumor-suppressor effects of chemical functional groups in an in vitro co-culture system

Liver normal cells and cancer cells co-cultured on surfaces modified by different chemical functional groups, including mercapto （-SH）, hydroxyl （-OH） and methyl （-CHz） groups. The results showed that different cells exhibited changes in response to different surfaces. Normal cells on -SH surface exhibited the smallest contact area with mostly rounded morphology, which led to the death of cancer cells, while cancer cells could not grow on -CH3 groups, which also died. In the co-culture system, the -CH3 group exhibited its unique effect that could trigger the death of cancer cells and had no effects on normal cells. Our findings provide useful information on strategies for the design of efficient and safe regenerative medicine materials.

Neonatal lethality and recycling defect of transferrin receptor in mice with Syntaxin12/13 disruption

Dear Editor,Iron deficiency,documented by World Health Organization(WHO),is the most common nutritional deficiency,and accounts for-50%of anemia globally.Iron-deficiency anemia is notably and frequently associated with chronic heart failure,chronic kidney disease,cancer and inflammatory bowel disease.According to WHO Global Health Estimates 2014 Summary,iron-deficiency anemia is a major and prevalent public health problem worldwide,which contributes to 0.2% mortality,especially maternal and child mortality.

ovAFLow:Detecting Memory Corruption Bugs with Fuzzing-Based Taint Inference

Grey-box fuzzing is an effective technology to detect software vulnerabilities,such as memory corruption.Previous fuzzers in detecting memory corruption bugs either use heavy-weight analysis,or use techniques which are not customized for memory corruption detection.In this paper,we propose a novel memory bug guided fuzzer,ovAFLow.To begin with,we broaden the memory corruption targets where we frequently identify bugs.Next,ovAFLow utilizes light-weight and effective methods to build connections between the fuzzing inputs and these corruption targets.Based on the connection results,ovAFLow uses customized techniques to direct the fuzzing process closer to memory corruption.We evaluate ovAFLow against state-of-the-art fuzzers,including AFL(american fuzzy lop),AFLFast,FairPuzz,QSYM,Angora,TIFF,and TortoiseFuzz.The evaluation results show better vulnerability detection ability of ovAFLow,and the performance overhead is acceptable.Moreover,we identify 12 new memory corruption bugs and two CVEs(common vulnerability exposures)with the help of ovAFLow.