归一化全矢能量在随机工况下齿轮微弱故障识别中的应用（英文）

随机工况下,转速和负载的不同会改变振动信号的幅频调制特性,使得风电机组齿轮箱局部微弱故障的诊断难度急剧增大,针对于此,提出采用不同的恒定工况替代随机工况,以归一化全矢频带能量实现随机工况下齿轮箱微弱故障的诊断。方法首先将随机工况分解成不同的恒定工况的组合,降低工况的维数,针对各恒定工况,采用全矢理论将同源信号进行融合,以保证微弱信号源信息的完整性,再利用FIR滤波对全矢信号进行分解,消除因工况的不同所造成的模态混叠的影响。考虑到转频处的频带能量能定量区分不同的工况,频带能量的变化率能实现齿轮工作状态的区分,而信息熵能准确反映信号激励源和激励方式的区别,提取各频带能量熵之和、转频处的频带能量及频带能量的变化率作为区分齿轮工作状态的特征向量,消除工况变化所造成的诊断干扰的同时有利于实现各种工况下的故障模式识别,达到随机工况下齿轮微弱故障诊断的目的。最后采用高斯混合模型对风电机组齿轮箱随机工况下的150组振动信号进行特征描述,运用最大贝叶斯分类器实现故障识别,故障识别率表明该方法可有效的识别随机工况下的齿轮早期局部微弱故障。

Selective flotation of smithsonite from dolomite by using novel mixed collector system

A novel mixed collector (BHOA) was prepared by mixing benzohydroxamic acid (BHA) and sodium oleate (NaOL) and applied to the flotation separation of smithsonite from dolomite. Flotation results showed that NaOL alone had good collecting performance on smithsonite and common gangue mineral dolomite but had poor selectivity. By using a BHA/NaOL mixed system with a molar ratio of 2:1, the recoveries of smithsonite and dolomite reached approximately 90% and 5%, respectively. Surface tension analysis showed that the surface activity of BHOA was a little higher than that of a single NaOL because of synergistic effects. Zeta potential and X-ray photoelectron spectroscopy measurements indicated that surfactants BHA and NaOL co-absorbed on the smithsonite surface and only NaOL was present on the dolomite surface in the presence of BHOA.

Current and future uses of skeletal stem cells for bone regeneration

The postnatal skeleton undergoes growth,modeling,and remodeling.The human skeleton is a composite of diverse tissue types,including bone,cartilage,fat,fibroblasts,nerves,blood vessels,and hematopoietic cells.Fracture nonunion and bone defects are among the most challenging clinical problems in orthopedic trauma.The incidence of nonunion or bone defects following fractures is increasing.Stem and progenitor cells mediate homeostasis and regeneration in postnatal tissue,including bone tissue.As multipotent stem cells,skeletal stem cells(SSCs)have a strong effect on the growth,differentiation,and repair of bone regeneration.In recent years,a number of important studies have characterized the hierarchy,differential potential,and bone formation of SSCs.Here,we describe studies on and applications of SSCs and/or mesenchymal stem cells for bone regeneration.

Preparation and performance of fluorescent polyacrylamide microspheres as a profile control and tracer agent

Polyacrylamide microspheres have been suc- cessfully used to reduce water production in reservoirs, but it is impossible to distinguish polyacrylamide microspheres from polyacrylamide that is used to enhance oil recovery and is already present in production fluids. In order to detect polyacrylamide microspheres in the reservoir pro- duced fluid, fluorescent polyacrylamide microspheres P（AM-BA-AMCO）, which fluoresce under ultraviolet irradiation, were synthesized via an inverse suspension polymerization. In order to keep the particle size distribu- tion in a narrow range, the synthesis conditions of the polymerization were studied, including the stirring speed and the concentrations of initiator, NaaCO3, and dispersant. The bonding characteristics of microspheres were deter- mined by Fourier transform infrared spectroscopy. The surface morphology of these microspheres was observed under ultraviolet irradiation with an inverse fluorescence microscope. A laboratory evaluation test showed that the fluorescent polymer microspheres had good water swelling capability, thus they had the ability to plug and migrate in a sand pack. The plugging rate was 99.8 % and the residual resistance coefficient was 800 after microsphere treatment in the sand pack. Furthermore, the fluorescent microspheres and their fragments were accurately detected under ultra- violet irradiation in the produced fluid, even though theyhad experienced extrusion and deformation in the sand pack.

The use of phalangeal plate as“hook plate”and external fixation to treat complex distal radius fracture fragments

Distal radius fracture is the most common fracture site of the human skeleton[1]and often occurs in young people resulting from high energy injury caused by severe trauma.However,complex distal radial intra-articular fractures(AO type C3)are relatively rare and account for about 5%of all distal radius fractures.[2]Fracture comminution at the joint surface is the primary manifestation of these fractures,followed by avulsion of the bone fragments with displacement seen at both the metacarpal and ulnar bone.Treatment of these displaced and unstable fractures remains a challenge.The nature of the articular surface fracture indicates the use of either the open or close reduction technique.Treatment protocols focus on extra-articular reduction and restoration of radial length,maintaining the volar tilt.[3,4]It has been noted that incongruity of the intra-articular distal radius fracture is relevant to the development of arthritis.[5,6]

Obstructive Sleep Apnea Hypopnea Syndrome as a Reason for Active Management of Pulmonary Embolism

Background：Obstructive sleep apnea hypopnea syndrome （OSAHS） constitutes an independent factor for high warfarin dose for patients with pulmonary embolism （PE）.The aim of this study was to investigate whether the 6-month anticoagulation treatment by warfarin is enough for patients with PE complicated by OSAHS.Methods：We investigated 97 PE patients,32 of them had OSAHS and 65 non-OSAHS.Warfarin was administered for 6-month if no abnormal circumstances occurred.All patients were followed up for 18 months.Adverse events （AE） included death,major bleeding,hospitalization due to heart failure or pulmonary hypertension,and recurrence or aggravation of PE （including deep vein thrombosis）.Recurrence rate of PE after warfarin cessation was compared between the two groups.Results：OSAHS patients required a significantly higher dose of warfarin than their non-OSAHS counterparts （4.73 mg vs.3.61 mg,P 〈 0.001）.During warfarin treatment,no major bleeding and aggravation of PE occurred among OSAHS patients,and the rates of various AE were not significantly different between the OSAHS and non-OSAHS groups.PE recurrence was higher in OSAHS than non-OSAHS groups after withdrawal of warfarin （21.43% vs.6.78%,P =0.047）.Compared with non-OSAHS patients,OSAHS group had lower international normalized ratio （INR） value but higher plasminogen on baseline and INR resumed to a relatively low level after warfarin discontinuation.Conclusions：OSAHS patients may present with hypercoagulation and relatively high-risk of recurrence of PE after cessation of 6-month warfarin treatment.

Analgesic and anti-inflammatory activities and mechanisms of 70% ethanol extract of Zygophyllum macropodum in animals

Objective： To screen the preliminary phytochemical components, to investigate the acute oral toxicity, the analgesic and anti-inflammatory effects, and to analyze inflammatory factors on mice or rats of 70% ethanol extract of Zygopgyllurn macropodum aerial parts （ZME）. Methods： Preliminary phytochemical screening was carried out by color reaction. Acute oral toxicity was investigated by body weight, relative organ weight and other toxic signs. Acetic acid induced writhing and hot plate test were used to determine analgesic effect. Acetic acid induced vascular permeability and carrageenan induced paw edema were used to confirm anti-inflammation. Protein in pleural effu- sion, prostaglandin E2 （PGE2） and tumor necrosis factor alpha （TNF-a） in serum of pleuritic rats induced by carrageenan were analyzed to explore the action mechanisms. The test groups received ZME with 100, 300, 600 mg/kg, the positive control with aspirin （ASP） 200 mg/kg for mice, and ZME with 70, 210, 420 mg/kg and ASP 150 mg/kg for rats orally. The control （C） or negative control （NC） groups received 2% Tween 80 of 10 mL/kg orally. Results： ZME contain flavonoids, saponins, phenols and tannins, steroids, terpenoids, fats and oils, glycosides, carbohydrates, and reducing sugar, but no alkaloids. The lethal dose 50% （LD50） of ZME was greater than 2000 mg/kg and no toxic or deleterious effects and death during 14 d. Oral administration 300 and 600 mgJkg of ZME produced analgesic and anti-inflammatory effects significantly （P 〈 0.05 or P 〈 0.001） vs NC. It can reduce the writhing number, prolong the heat resisting time, suppress the permeability of the capillary wall increasing, mitigate the paw edema, reduce the content of protein in pleural effusion, and reduce PGE2 and TNF-α in blood. Conclusions： ZME possessed analgesic and anti-inflammatory activities which related to inhibit the production of protein, PGE2 and TNF-α. The LD50 of ZME treated orally to mice was greater than 2000 mg/kg.