关于旋装滤快速干检研究

目的为试验研究旋装滤生产过程中应用快速干检的效果。方法是通过干检原理取代传统的浸水测漏方法,制作密封罩式检测工装,利用电脑组态软件分析检测数据的精度。结果通过资质密封罩检测工装,把旋装滤产品装入密封罩内,充入0.5 MPa的气体,在密封罩和产品之间的微小间隙连接压力传感器,使用标准气体针筒注入额定气体量,检测出来密封罩和产品间隙之间微小空间的压力变化,与注入气体数值比较,实际精度可以有效控制在0.5cc以下,证明这种缩小检测产品容积的方法可以满足旋装滤生产过程中的快速高精度检测,也可以在类似产品和密封性要求的环境下应用。

高效换热管压差干检系统研制

本文将总体介绍高效换热管压差干检系统的设计、集成。分别从如何实现高效换热管的单支自动上下料、试压过程高效换热管的夹紧、密封及泄露判定等方面进行详细介绍。从而实现全自动化试压的过程。整个压差干检系统的运用,很好的将员工从重复、繁琐的工作中解放出来,在实现生产效率提升的同时,检测精度达到0.05 mm。有效避免了泄漏误判,解决了微泄漏孔无法检测的难题。

临床尿沉渣分析仪检测尿中红细胞假阳性的分析

尿常规检测是传统三大常规检测项目之一,近年来,由于各种尿液分析仪的广泛使用,部分检验室尿化学检查依赖于尿液分析仪的简便快捷,甚至用尿沉渣分析仪取代了传统尿沉渣镜检。本文通过尿沉渣分析仪与尿沉渣镜检结合干化学分析的对比,就我院尿沉渣分析仪的红细胞假阳性原因在工作中的应用进行了分析,探讨。

低温对干化学法测定尿白细胞的影响

干化学法易受尿液中一些物质的影响,影响检验结果的准确性。我们发现环境温度低时干化学法实验结果会出现假阴性或者阳性强度降低的现象。1 材料与方法标本来源:160份患者的当天清洁中段晨尿。

22份菜豆(Phaseolus vulgaris L.)种质健康研究

通过使用干检和吸水纸培养 2种方法 ,对种皮为无色素组和有色素组的 2 2份菜豆种质进行了健康检测研究。结果表明 ,肉眼可检测菜豆种子外观病害症状为虫蛀、皱缩、畸形和种皮变色。吸水纸培养检测发现在 2 2份材料中共携带可知真菌 11种 ,互隔交链孢霉 (Alternariaalternata) ,镰刀菌属 (Fusariumspp .) ,青霉属 (Penicilliumspp .) ,根霉属 (Rhizopusspp .)存在于绝大多数的供试材料中。种皮有色的种子真菌携带种类和感染百分率均低于白色种皮的种子。种子畸形和皱缩严重影响种子的发芽成苗能力。肉眼检测菜豆种子外观健康结果可作为有效指标来判定种质的健康状况。

GNSS spoofing detection based on uncultivated wolf pack algorithm

In order to solve the problem that the global navigation satellite system（GNSS） receivers can hardly detect the GNSS spoofing when they are deceived by a spoofer,a model-based approach for the identification of the GNSS spoofing is proposed.First,a Hammerstein model is applied to model the spoofer/GNSS transmitter and the wireless channel.Then,a novel method based on the uncultivated wolf pack algorithm（UWPA） is proposed to estimate the model parameters.Taking the estimated model parameters as a feature vector,the identification of the spoofing is realized by comparing the Euclidean distance between the feature vectors.Simulations verify the effectiveness and the robustness of the proposed method.The results show that,compared with the other identification algorithms,such as least square（LS）,the iterative method and the bat-inspired algorithm（BA）,although the UWPA has a little more time-eomplexity than the LS and the BA algorithm,it has better estimation precision of the model parameters and higher identification rate of the GNSS spoofing,even for relative low signal-to-noise ratios.

AN ALGORITHM OF DISTANCE CALCULATION BETWEEN A BOUNDING SPHERE AND A BOUNDING CSG PRIMITIVE

A simple method for calculating distance between a solid sphere and a constructive solid geometry (CSG) so lid primitive (including block, cone, cylinder, sphere, wedge and torus) is derived to support the collision detection algorithm. By decomposing the whole space into relative positions and geometric features of the sphere and the primitive considered, closed form distance formula are got. These calculations are very useful in the real time collision detection in which primitives are used as bounding volumes of complex objects.

KEY TECHNOLOGY OF SOLID SIMULATION SYSTEM OF NC MILLING MACHINING

A system architecture of solid-based NC simulation for milling machining is given, the function of which is composed of cutting simulation of different cutters, such as flat-end cutters, ball-end cutters, dome-end cutters, angle cutters and drill cutters, rapid pre-checking of interference, detection of collision, and visualization of over cut in the stock. A new method based on the design model is raised to detect the collision and pre-check the interference during NC milling machining. A special problem about the construction of a cutter′s swept volume, self-intersection is discussed. All the work on the construction, the subtraction and the display of solids is accomplished with the help of ACIS 3-D modeling.

Low complexity iterative differential decoding algorithm for multiband UWB communication systems

Due to not requiring channel state information （CSI） at both the transmitter and the receiver, noncoherent ultra-wideband （UWB） incurs a performance penalty of approximately 3 dB in the required signal to noise ratio （SNR） compared to the coherent case. To overcome the gap, an effective differential encoding and decoding scheme for multiband UWB systems is proposed. The proposed scheme employs the parallel concatenation of two recursive differential unitary space-frequency encoders at the transmitter. At the receiver, two component decoders iteratively decode information bits by interchanging soft metric values between each other. To reduce the computation complexity, a decoding algorithm which only uses transition probability to calculate the log likelihood ratios （LLRs） for the decoded bits is given. Simulation results show that the proposed scheme can dramatically outperform the conventional differential and even coherent detection at high SNR with a few iterations.

Ordered successive noise projection cancellation algorithm for dual lattice-reduction-aided MIMO detection

A novel nonlinear multi-input multi-output MIMO detection algorithm is proposed which is referred to as an ordered successive noise projection cancellation OSNPC algorithm. It is capable of improving the computation performance of the MIMO detector with the conventional ordered successive interference cancellation OSIC algorithm. In contrast to the OSIC in which the known interferences in the input signal vector are successively cancelled the OSNPC successively cancels the known noise projections from the decision statistic vector. Analysis indicates that the OSNPC is equivalent to the OSIC in error performance but it has significantly less complexity in computation.Furthermore when the OSNPC is applied to the MIMO detection with the preprocessing of dual lattice reduction DLR the computational complexity of the proposed OSNPC-based DLR-aided detector is further reduced due to the avoidance of the inverse of the reduced basis of the dual lattice in computation compared to that of the OSIC-based one. Simulation results validate the theoretical conclusions with regard to both the performance and complexity of the proposed MIMO detection scheme.

浅谈小型非标机电设备设计

非标机电设备是根据企业现场实际需要量身定做的,可以实现标准机械所不能实现的一些功能。下面就以我参与设计生产过的"桥壳捡漏机"为例谈一下非标机电设备设计。首先由企业根据用户要求接下任务立项;接下来为实现项目任务书的要求,经过原理分析及计算,提出总体方案;然后技术设计、制造;试制调试,交付使用。

Narrow-band imaging without magnification for detecting early esophageal squamous cell carcinoma

AIM：To compare narrow-band imaging（NBI）without image magnification,and chromoendoscopy with Lugol＇s solution for detecting high-grade dysplasia and intramu-cosal esophageal squamous cell carcinoma（SCC）in patients with head and neck cancer.METHODS：This was a prospective observational study of 129 patients with primary head and neck tumors consecutively referred to the Gastrointestinal Endoscopy Unit of Hospital das Clínicas,Sao Paulo University Medical School,Brazil,between August 2006 and Feb-ruary 2007.Conventional examinations with NBI and Lugol chromoendoscopy were consecutively performed,and the discovered lesions were mapped,recorded and sent for biopsy.The results of the three methods were compared regarding sensitivity,specificity,accuracy,positive predictive value,negative predictive value,positive likelihood value and negative likelihood value.RESULTS：Of the 129 patients,nine（7%）were diag-nosed with SCC,5 of which were in situ and 4 which were intramucosal.All carcinomas were detected through NBI and Lugol chromoendoscopy.Only 4 le-sions were diagnosed through conventional examination,all of which were larger than 10 mm.CONCLUSION：NBI technology with optical filters has high sensitivity and high negative predictive value for detecting superficial esophageal SCC,and produces results comparable to those obtained with 2.5%Lugol chromoendoscopy.

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS (Micro-Electro-Mechanical Systems) are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.

An improved linear dispersion codes transmission scheme based on OSIC detection

Linear dispersion codes (LDCs) were originally designed based on maximum likelihood detection. They do not have good performance when using ordered successive interference cancellation (OSIC) detection. In this paper,we propose a new improved linear dispersion codes transmission scheme to combat performance loss of original LDCs when using OSIC detection. We introduce an interleaver to each data substream transmitted over different antennas after LDCs encoder. Furthermore,a new computer search criterion for a linear transformation matrix is also proposed. New search criterion is to minimize the symbol error rate based on OSIC detection. Computer simulations show that the performance of proposed LDCs transmission scheme is better than the original LDCs.

A Linear Interference Cancellation Multi-User Detector for Synchronous CDMA Communications

This paper describes a linear interference cancellation multi user detector for synchronous DS CDMA systems under the condition that all spread spectrum code waveforms have the constant cross correlating coefficients. The basic idea is to get the estimation for total multiple access interference (MAI) of all users using a reference code waveform, then subtract the total MAI from the received signal. The structure of such a detector is nearly similar to the conventional detector. The BER expression obtained in the paper shows significant performance improvement compared to the other detectors.

The anthropogenic acceleration and intensification of flash drought over the southeastern coastal region of China will continue into the future

The frequent and rapid onset of flash drought poses a serious threat to agriculture and ecosystems.Detecting human influences on flash droughts and estimating their future risks under climate change have attracted great attention.Focusing on a record-breaking flash drought event in the southeastern coastal region of China in summer 2020,the authors found that the suppression of convective precipitation and high temperature caused by the persistent high geopotential height anomalies and land-atmosphere dry coupling were important reasons for the rapid onset and strong intensity of the flash drought.Event attribution analysis with the latest CMIP6 data showed that anthropogenic climate change has not only increased the likelihood of an onset speed and intensity like those of the 2020 flash drought event,by about 93%±20%and 18%±15%,respectively,but also increased the chance of their simultaneous occurrence,by about 86%±38%,according to their joint probability distribution.Under a business-as-usual future scenario(SSP2-4.5),the likelihood of such an onset speed,intensity,and their simultaneous occurrence will further increase,by 85%±33%,49%±8%,and 81%±48%,respectively,as compared with current climate conditions.This study highlights the importance of anthropogenic climate change for accelerating and intensifying flash drought in the southeastern coastal region of China.

Generalized Maximum Likelihood Noncoherent Block Detection for Decode-and-Forward Relay Systems

This paper considers noncoherent cooperative decode-and-forward(DF) halfduplex multi-branch relay systems.Each relay branch is modeled as a probabilistic transition system at the last hop,and thus it can be considered as a relaying chain comprising multi-hop relays.An approximation to the generalized maximum likelihood(ML) noncoherent block detection is derived for uncoded M-ary modulation in a faded noisy environment.In particular,the derived noncoherent block detection in a noiseless case is equivalent to a multichannel reception with full diversity.Furthermore,the generalized detection is extended specifically to block coded M-ary phase shift keying(MPSK) modulation.For a DF three node relay system using block coded quadrature phase shift keying(QPSK),simulation results are provided to examine the end-to-end error performance of the noncoherent detection with considering the effects of network geometry and power allocation,respectively.It is shown that under a fixed power allocation,a proper relay placement can yield near full diversity for large signal-to-noise ratio.

Iterative Noncoherent Block Detection of Coded MPSK for Cooperative Relay Systems

Maximum likelihood(ML) noncoherent block detection techniques are investigated for block-coded MPSK modulation in cooperative decode-and-forward relay systems over slow fading channels.A decision-directed iterative Viterbi algorithm(IVA) is derived for a suboptimal ML noncoherent detection.Simulation results show that the IVA can approach the error performances of the exhaustive detection method but at a lower complexity.

Endoscopic diagnosis of gastrointestinal graft-versus-host disease

AIM:To evaluate the diagnostic value of endoscopy in patients with gastrointestinal graft-versus-host disease (GI GVHD). METHODS:We identified 8 patients with GI GVHD following allogeneic hematopoietic stem cell trans-plantation (HSCT). GVHD was defined histologically as the presence of gland apoptosis, not explained by other inflammatory or infectious etiologies. RESULTS:The symptoms of GI GVHD included anorexia, nausea, vomiting, watery diarrhea, abdominal pain, GI bleeding, etc. Upper endoscopic appearance varied from subtle mucosal edema, hyperemia, erythema to obvious erosion. Colonoscopic examination showed diffuse edema, hyperemia, patchy erosion, scattered ulcer, sloughing and active bleeding. Histological changes in GI GVHD included apoptosis of crypt epithelial cells, dropout of crypts, and lymphocytic infiltration in epithelium and lamina propria. The involvement of stomach and rectocolon varied from diffuse to focal. CONCLUSION:Endoscopy may play a significant role in early diagnosis of GI GVHD patients following allogeneic HSCT, and histologic examination of gastrointestinal biopsies is needed to confirm the final diagnosis.